MUR5_Accumulator_Design_for_an_FSAE_Elec

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MUR5: Accumulator Design for an FSAE Electric Car
Accumulator
Christian Ratnapalasari (605914)
Williem Kartasasmita (617649)
FoadMunir (735054)
October 27, 2017
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Accumulator
Abstract
This year, Melbourne University Racing is developing its first ever electric car for the FSAE competition in
addition to the combustion engine car. This report discusses the design of an accumulator pack and the trac-
tive system for an FSAE electric race car. The accumulator is a custom-built lithium ion battery pack that
includes everything required for safe operation and to supply power to the motor controllers. FSAE con-
straints for the competition are met by conducting a thorough research on cells, container design and safety
switches. Cell selection is done based on their chemistries, packaging, performance and safety. A Literature
review to understand cell behaviour and characteristics at different temperature, charge/discharge rate and
series/parallel configuration. This information is vital for the other MUR sub-team to be able to design an
effective BMS system that manages the entire pack and to be able to finish the endurance competition.
Furthermore, to package the entire pack safely a container is designed in line with the FSAE require-
ments. To minimize risk, safety procedures were developed to as this is the first time MUR is building an
electric car. These included Risk Analysis, Standard Operating Procedures and Hazardous Voltage Train-
ing. The results show that the designed accumulator can supply the power required by the motors during
car operation and stores enough energy to complete endurance.
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Accumulator
Acknowledgements
We would like to thank Associate Professor Tansu Alpcan for being a helpful presence throughout the year
and for his guidance. We would also like to thank Professor Jamie Evans for his invaluable feedback.
We are also indebted to theAccumulator team of 2016which included Shiddij Shrestha, SamBarrett and
Muyao Li for doing preliminary research for the accumulator and all their help throughout the year. Shiddij
Shrestha alongwithMaximilianUeda and Brennan Lamwere part of the Integration sub-team of 2017, they
helped us a lot this year and we really appreciate their support.
We are also very grateful to our Hazardous Voltage Instructor Bryce Gaton for his help with the safety
and implementation of our project. The team is also very grateful to Tashdid Tahmid for his insights about
the mechanical aspects of the project.
Furthermore, we would also like to thank Kevin Smeaton, Justin Fox and Oktay Balkis from Univer-
sity of Melbourne Engineering Workshop and Randy De Rosario from Holmesglen Institute of TAFE for
providing facilities and guidance for component manufacturing.
Last but not the least the charge cart team which included Kusal Kithul-Godage, Jocelyn Choy, Karina
Lee, Juan Carlo Ala and Xinran Zhang. Ryan Carter was a helpful guidance throughout the year and we
appreciate all his help.
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Accumulator
Symbols and Acronyms
3D = Three Dimensional
ABS = Acrylonitrile Butadiene Styrene
AC = Alternating Current
AIL = Accumulator Indicator Light
AIR = Accumulator Isolation Relay
BJT = Bipolar Junction Transistor
BMS = Battery Management System
BOL = Beginning of Life
BSCS = Battery Safety Charging System
CAD = Computer-Aided Drawing
CAM= Computer-aided manufacturing
CAN = Controller Area Network
CNC = Computer numerical control
CCV = Closed Circuit Voltage
DC =Direct Current
DCR =Direct Current Resistance
DOD =Depth of Discharge
EPT = Electric Powertrain
EV = Electric Vehicle
FSAE = Formula SAE
HVD =High Voltage Disconnect
HVIL =High-Voltage Interlock Loop
IC = Internal Combustion
kW = kiloWatt
kWh = kilowatt-hour
LED = Light Emitting Diode
LiCoO2 = Lithium cobalt oxide
LiFePO4 = Nano-phosphate/lithium iron phos-
phate
Li2MnO4 = Lithiummanganate
LiMnNiCo = Lithiummanganese nickel cobalt
Li4Ti5O12 = Lithium-titanate
LiPo = Lithium polymer
LiNiO2 = Lithium-nickel-oxide
LCD = Liquid Crystal Display
LV = Low Voltage
MOSFET =Metal Oxide Semiconductor Field Ef-
fect Transistor
MSD =Manual Service Disconnect
MUR =Melbourne University Racing
MUR-E=Melbourne University Racing - Electric
NiMH =Nickel Metal Hydride
OH&S =Occupational Health and Safety
PLA = Polylactic Acid
PCB = Printed Circuit Board
SAE = Society of Automotive Engineers
SOC = State of Charge
SOH = State of Health
TAFE = Technical and Further Education
TSAL = Tractive System Active Light
TSMP = Tractive SystemMeasuring Points
TSMS = Tractive SystemMaster Switch
UART=Universal AsynchronousReceiverTrans-
mitter
VDC = Voltage DC
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Contents
1 Introduction 7
1.1 FSAE Competition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2 Melbourne University Racing - Electric . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3 Tractive SystemOverview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.4 Project Aims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.5 Team Accomplishments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2 Literature Review 10
2.1 Battery Pack Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2 Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3 Cell Selection 11
3.1 Lithium Ion Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2 Cell Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.3 Cell Enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.4 Lithium Ion Chemistries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.5 Lithium Iron Phosphate (LiFePO4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.6 A123’s AMP20M1HD-A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4 Safety 18
4.1 Lithium Ion Battery Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.2 Safety Incidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.3 Emergency Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.3.1 Hot Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.3.2 Vented Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.3.3 Cell/Battery Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.3.4 First Aid Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.3.5 Fire Fighting Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.3.6 Personal Protective Equipment: . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.4 Risk Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.4.1 Single Cell Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.4.2 High(Hazardous) Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.5 Standard Operating Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.5.1 Cell Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.5.2 Cell Charging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4.5.3 Module/Accumulator Assembly & Testing . . . . . . . . . . . . . . . . . . . . . 36
4.5.4 Swapping Damaged Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.5.5 Accumulator Removal and Charging . . . . . . . . . . . . . . . . . . . . . . . . 41
4.5.6 Low Voltage Wire Crimping . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5 Design Development 45
5.1 Design Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.2 Cell Segmentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 45
5.2.1 Initial Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.2.2 Cooling Plate/Fins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
5.2.3 Cell Interconnection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
5.2.4 Prototyping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.2.5 Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.2.6 Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
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5.3 Low Voltage Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
5.4 Accumulator Isolation Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
5.4.1 Contactor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
5.4.2 Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5.5 Tractive System Active Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5.6 Container/Housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5.6.1 Container Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
5.6.2 Thermal Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.6.3 Extra Safety Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.7 Tractive SystemWiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.8 High Voltage Disconnect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
5.9 Tractive SystemMeasuring Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
5.10 Tractive SystemMaster Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.11 Charge Cart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.11.1 FSAE Rule Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.11.2 Cart Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.11.3 Material Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.11.4 Wheel Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5.12 Accumulator Indicator Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5.12.1 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
5.12.2 Schematics andWiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
5.12.3 HV Section Schematic Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
5.12.4 LV Section Schematic Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
5.12.5 Safety Extension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
5.12.6 Component Placement in the Car . . . . . . . . . . . . . . . . . . . . . . . . . 62
5.13 Precharge Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
5.13.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
5.13.2 Design Consideration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
5.13.3 Component Placement in the Car . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.14 Discharge Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.14.1 Design Consideration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.14.2 Component Placement in the Car . . . . . . . . . . . . . . . . . . . . . . . . . 65
6 Design Implementation and Testing 66
6.1 Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
6.1.1 Transforming Design for Manufacture Process . . . . . . . . . . . . . . . . . . . 66
6.1.2 Laser Cut Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
6.1.3 Water Jet Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
6.1.4 CNCMachined Components . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
6.1.5 3D Printed Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.1.6 Components using hand tools . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.2 Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.2.1 Segment Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.2.2 Low Voltage Battery Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6.2.3 Container Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
6.3 BMS Implementation to the segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
6.4 Further implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
6.5 Cell Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
6.5.1 Individual Cell Acceptance Testing . . . . . . . . . . . . . . . . . . . . . . . . . 73
6.6 Load Bank 2016 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
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6.6.1 Prototype andModel Development . . . . . . . . . . . . . . . . . . . . . . . . 73
6.6.2 Procedure and Technicality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6.6.3 Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.6.4 Safety Consideration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
6.7 Load Bank 2017 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
6.7.1 Design andModel Development . . . . . . . . . . . . . . . . . . . . . . . . . . 77
6.7.2 Internal Circuitry and Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.8 Testing Data and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
6.9 Battery Safety Charging System (BSCS) . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.9.2 Risks and Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.9.3 Charging Characteristic and Safety . . . . . . . . . . . . . . . . . . . . . . . . . 84
6.9.4 Design and Final Product . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
7 Conclusion 86
Bibliography 87
A Appendix 91
A.1 Datasheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
A.1.1 High Voltage Disconnect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
A.1.2 Tractive SystemMeasuring Points . . . . . . . . . . . . . . . . . . . . . . . . . 92
A.1.3 A123 Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
A.1.4 EmraxMotor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
A.2 Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
A.2.1 Microcontroller Code: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
A.2.2 Raspberry Pi Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
A.3 Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
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1 Introduction
Accumulator is a British term for a large rechargeable battery[1]. The accumulator is a custom-built lithium
ion battery pack that includes everything required for safe operation and to supply power to the motor
controllers. This will be built for an electric race car which will compete in the FSAE competition. The
competition details and Melbourne University’s Racing teams’ details along with an introduction to some
of the systems found in the car and the project aims are discussed below.
1.1 FSAE Competition
Formula SAE Australia is a competition run by the Society of AutomotiveEngineers (SAE) since 1978 with
combustion engine vehicles and then expanded to include electric vehicles. The competition is held every
year at various locations around the world with the aim of challenging the students to design and construct
a racing electric car. This allows the students to get hands on experience and work on real problems. There
are two types of events at the competition: static and dynamic. Static events include details of the design and
manufacturing processes and dynamic events test the vehicle based on its performance.[2]
Table 1: FSAE Competition - Dynamic Events [2]
Event Name Points
Endurance 300
Autocross 150
Efficiency 100
Acceleration 75
Skid-Pad 50
Table 2: FSAE Competition - Static Events [2]
Event Name Points
Engineering Design 150
Cost Analysis 100
Business Preparation 75
1.2 Melbourne University Racing - Electric
Melbourne University Racing (MUR) began with the inception of the FSAE competition in 2000. MUR
decided to participate in the electric competition (FSAEAustralia Electric); this change has introduced a host
of new engineering challenges in the design of a safe and reliable electric tractive system. The team is made
of mechanical and electrical engineering students who build a combustion and an electric race vehicle over a
12-month design cycle. Approximately 25 final year engineering students work on the electric car in different
sub-teams. These include the following electrical sub-teams:
• Integration
• Accumulator
• Battery Management System
• Electric Power Train
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• Low Voltage Systems
Accumulator sub-team is responsible for designing the battery pack and it’s charging, isolation of high
voltages/currents and ensuring the safety of all electrical systems.
1.3 Tractive SystemOverview
The tractive system or the energy storage system of the car along with the electric powertrain can be seen
in Figure 1. Tractive system includes the accumulator, battery management system, Accumulator Isolation
Relays(AIRs) and the Shutdown Circuit. Accumulator provides power to the twomotor controllers which
take input from the Vehicle control unit to run motors each connected to one of the rear wheels of the car
respectively.
Vehicle Control Unit
Battery
Management
System
Accumulator
AIRs
Shutdown Circuit
Sensors
Motor Controller
Motor Controller
Motor
Motor
Figure 1: Overview of Tractive System and Electric Powertrain [3]
Accumulator and battery management system (BMS) are usually in the same container. There are two
containers that hold the accumulator segments. These are made from Aluminium with their thickness de-
termined by the FSAE rules. BMSmanages the individual cells within the accumulator to deliver maximum
performance out of the cells. Shutdown circuit consists of a series of safety switches as recommended by
the FSAE rulebook; these can open the Accumulator Isolation Relay (AIR) to disconnect the accumulator
from the rest of the tractive system. This allows for the maintenance and troubleshooting of all the other
components in the tractive system if there is a need.
Both the endurance race and the acceleration event test the accumulator, as during endurance, the accu-
mulatormust contain enough energy andduring the acceleration event, and itmust also be able to supply the
maximum power allowed by the rules. So, the considerations for cell selection is cell current output, energy
density, cell weight, costs of battery cells and cell monitoring on top ofmeeting the FSAE rule requirements.
The ideal battery pack is made from reliable, powerful cells with a high energy density to complete the
endurance event and ahigh specific power tomeet thepowerneeded to create themaximumtorque. Lithium
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Ion batteries were selected because they are cheap per Watt-hour and can be optimised for both Specific
Power and Specific Energy.
Figure 2: Specific Energy and Specific Power by Type of Battery [4]
1.4 Project Aims
The Accumulator team is responsible for the design of the tractive system of the electric car. This includes:
• Accumulator pack and its container
• Accumulator Insulation Relay (AIR)
• High Voltage Disconnect (HVD)
• Tractive System Active Light (TSAL)
• Tractive SystemMeasuring Points (TSMP)
• Tractive SystemMaster Switch (TSMS)
• Tractive System Connections andWiring
• Charge Cart
The aim of the project was to deliver a safe, high performance accumulator that could deliver the maxi-
mumpower (80 kW) to the tractive systemduring the acceleration event and to allow the electric car to finish
endurance race by being able to store sufficient energy. Moreover, all the FSAE competition rules must be
satisfied.
Thedetails of all the tractive systemcomponentswill be discussed later in the designdevelopment section
where the design objectives and the constraints related to each of these components.
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1.5 Team Accomplishments
The teammetmost of the objectives set out at the start of the project. As the electric team is in the process of
developing the first ever electric car, the teamperformed the vital task of conducting risk analysis, developing
standard operating procedures and raising awareness about how crucial it is to prioritise safety over all other
things. In the past, almost all the teammembers of the MUR team were mechanical engineers and they did
not appreciate the safety challenges that would be present in the development of an electric car. So, getting
this message across is perhaps the most important contribution that the accumulator sub-team made to
MUR Electric.
Moreover, after conducting literature review and analysing the different designs implemented by various
FSAE teams and by commercial car manufacturers, the team selected the cell chemistry and designed the
segment for this cell. The segment would be part of the battery pack and allows for a way to keep the design
and assembly process safer. A charge cart to safely transport cells and segments was also designed. As there
was no safe way to test cells and to characterise them, a testing jig and an improved load bankwere developed
whichwere then used for cell testing and helped the accumulator teamprovide important data to the battery
management system sub-team. Accumulator sub-team also collaborated with other Electrical sub-teams
within the MUR-Electric team to ensure that all the sub-systems being developed were safe, met the design
requirements and would be integrated properly.
2 Literature Review
The following section summaries the background materials read to gain understanding of the accumulator
system. Such information is crucial to assist in design and decision making.
2.1 Battery Pack Configuration
Batterypack configuration is onemaindesign elements of the accumulator system. MITusedA123’sAMP20M1HD-
A pouch cells which use LiFePO4 chemistry, which is relatively safer than other chemistries. They used 28
of these cells inside one segment[3], having a total of three segments. This is significantly small amount
compared to the amount of energy used by the commercial/passenger vehicles.
They used these cells because each individual cell does not have an enclosure, which results in reduced
weight of the overall pack. These cells also require a constant and even pressure applied across their face to
work well, otherwise they result in reduced performance. Therefore, they designed it with plates in between
cells that when compressed together in a pack, apply even pressure. They also clamped their cell tabs so that
they form a series connection rather than drilling holes in the tabs, this is an excellent approach and allows
them to replace any of their cells easily in case they are damaged.
As a comparison,TeslaMotors uses 6,831 small cylindrical Li-ion (LiMn2O4) batteries for theirRoadster.
A smaller vehicle, NissanLeaf, uses 192 prismatic Li-ion (LiMn2O4)[5]. The latter beingmore closely related
and comparable as the battery type used is widely implemented in FSAE teams.
Thereare a lot of other FSAE teams around the world who have developed electric cars and a few of
those designs are compared here to see what goes into making a safe battery pack. Purdue Electric Racing in
Indiana, USAusedMelasta/LiPo cell 3.7V 7050mAH, 20C for their 2014 carwhich also had a pack voltage of
300V.[6] Due to its high energy and small package size, these cells result in a small accumulator pack. This
has a few benefits such as the pack being easy to install in the car and adding less weight to the car, hence
becoming more suitable for a race car where performance must be maximized, and space is at a premium.
But on the flipside, this also makes it a potential unsafe battery pack because high energy packed in a small
space means more danger to personnel in the case that something goes wrong.
University of Kansas used Haiyin Lithium Polymer cell in a 72s4p (72 cells in series and 4 in parallel)
configuration for their 2013 car which results in a voltage of 302.4V for the battery pack.[7] This battery was
made up of twopacks eachwith 36s4p configuration.[7]Theywere connected in series to form a full battery.
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This is a relatively low voltage as compared to some of the newer packs being developed by teams around the
world which is because back then the maximum voltage allowed by the rules was lower than it is now.
The 2016 University ofWisconsin-Madison car used a cylindrical, 2.5 Ah lithium polymer cells in a stan-
dard 18650 form factor fromSamsung. These Samsung INR18650-25R cells have amaximumvoltage of 4.2V
and these were then assembled in to the 1s8p configuration sub-module from Energus Power Solutions who
sponsored their team and supplied them with Li8P25RT sub-modules.[8] This allowed them to not have
to worry too much about designing their own modules. Their accumulator is separated into 5 isolated bat-
tery sections, each containing 6 series connections of the Li8P25RT sub-modules. Each battery section has
a peak voltage and energy capacity of 25.2 V and 5.8 MJ, respectively. [8] The sections of the accumulator
were physically separated by the steel internal walls, and the batteries themselves were physically separated
by the non-conductive, UL 94 V-0 rated plastic enclosures. Internal cell fusing was included in the Energus
Power Solutions package, with 32 fuses included in each 1s8p package (2 fuses on each cell end).[9] The fuses
were made of nickel wire and are welded straight to the cells and copper conductor. This was an interesting
solution because having a fuse for each cell adds an extra layer of safety to the pack. This was also almost
impossible to do in a pack made from pouch cells as it requires drilling holes in the tabs because the manu-
facturers usually don’t drill these holes themselves. The holes essentially reduced the surface area of the tabs
and with some specific patterns impressed into the tabs, they can act like fuses for some value of current.
2.2 Cabling
There are a few different standards available in terms of electrical cabling. One size standard is called the
American Wire Gauge, which as its name indicates, used widely in the United States. Another standard
and the one used in Australia is simply called the standard international size, differentiated based on the
cross-sectional area in mm2. The wider the cross-section area, the more current the cable can deliver. Al-
though, the length of the cable also plays a role in the current carrying capability, shorter being the better
choice[10]. While the purpose of use will be on an electric race car, welding cable is suitable as it provides
double insulation and high current flow capability.
3 Cell Selection
Cell selection is one of the most important tasks for an electric FSAE car as the battery pack essentially fu-
els the car. This decision, made very early in the design stage affects not only the tractive system but also
the performance of the whole car. This process is not an easy one to make as cells come in many different
chemistries and various packaging styles; each with their own advantages and disadvantages. On top of that,
there is a wide range of manufacturers such as A123, Kokam, EIG, K2 Energy, Thundersky, Melasta etc. Ide-
ally, one would want to build a tractive system with excellent safety, high specific energy and specific power,
good temperature characteristics, long cycle life, low cost and zero maintenance[11]. Cells when connected
in parallel form blocks and when cells/blocks are connected in series, they form a battery.
3.1 Lithium Ion Cells
A lithium ion cell is an electrochemical device that can store and release energy. Lithium is the lightest metal
available in theworld and it has become the replacement for lead in cell chemistries because of its lightweight
properties. [12] These days lithium ion cells find application in almost all electronic devices and even hybrid
and electric cars. The reason for this is very simple; they offer high energy density which means the devices
can be powered for longer. Lithium ion cells have some special characteristics that are not found in other
types of cells.
• They have nomemory effect [13] which allows users to charge and discharge themmuchmore flexibly
than other batteries.
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• No metallic lithium is normally found inside a lithium-ion battery cell. This not only improves the
safety of the cell but also improves the ability of the battery to cycle many times. [14]
• Lithium ions are intercalated into the electrodematerials in both the electrodes. Intercalation is highly
reversible, compared to many other electrochemical processes, leading to electrode stability and high
cycle life of lithium ion batteries. [14]
• Lithium-ion batteries have very low self-discharge rates compared to other types of batteries. [14]
• Lithium-ion batteries generally offer a very high coulombic efficiency throughout the state of charge
range. [14]
• Other types of batteries are capable of being trickle-charged continuously at a low rate, even after 100%
SOC has been reached but Lithium-ion batteries cannot be trickle charged as even very low rates will
lead to overcharging, battery damage, and possible unsafe conditions. [14]
• High voltages present in lithium ion cells means that non-aqueous electrolyte (electrolysis begins to
occur around 2V) must be used. It is composed of organic solvents that are flammable and have high
vapour pressures. The flammability andhigh reactivity of these electrolytes posesmore severe flamma-
bility hazards than other types of batteries. [14]
Lithium ion batteries are often selected for an application based on their high energy content and power
capability, but this high performance can lead to a higher severity event if things gowrong. Short-circuit cur-
rents can be much higher and an uncontrolled release of energy can be larger. In addition, many additional
internal reactions that take place during the breakdown of lithium-ion cells can release additional energy.
[14]
Specifically, LithiumCobalt batteries have beenmuchmore commonly used for these applications, but a
newer technologyhas emergedwhich is lithium ironphosphate (LiFePO4) and is very stable to charge/discharge.[15]
3.2 Cell Components
A lithium ion cell consists of the following components:[14]
• Positive electrode
• Negative electrode
• Electrolyte
• Separator
• Enclosure
The cathode is the “positive” half of the cell while the anode is the “negative” half of the cell and is usu-
ally made up of a thin copper substrate that is coated with the active anode material. [16] The positive
electrode is made from lithium iron phosphate and negative electrode is usually carbon (graphite).[12] Be-
tween these two is a separator that prevents the two halves from touching and creating a short circuit. These
three components are assembled together to form the electrodes and are either wound or stacked to form
what is referred to as a jellyroll. [16] Electrodes consist of electrode material that is coated ontoa metal foil
that acts as a substrate and current collector. Electrode material contains active material that stores lithium,
substances to increase conductivity of both lithium ions and electrons and binders and other materials to
provide structural integrity and good adhesion to the metal foil, provide electronic conductivity between
the active material particles and the current collector and ionic conductivity between the electrolyte and the
active material.[14]
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Figure 3: Cell components [17]
Most of the electrolyte is absorbed into the active material and separator in lithium ion batteries which
is different from the wet batteries. The entire cell must be enclosed in a container which must be sealed to
prevent electrolyte loss and contamination. It must also be durable enough to protect the contents of the
cell and offer some resistance to abuse. [14] There are many other components such as a current interrupt
device (CID) or a positive thermal coefficient (PTC) which is a re-settable thermal fuse. But these are not
included in all cell types or chemistries.[16]
3.3 Cell Enclosure
Lithium ion cells are available in these formats:[18]
• Cylindrical
• Prismatic
• Pouch
Cylindrical cells inherently retain their shape against expansion due to chemical processes when fully
charged, while the user must provide an overall battery enclosure with other formats to retain their expan-
sion. [18] The highest volume lithium-ion cell format in production today by far is the 18650 cylindrical cell
with nearly 660 million cells produced annually [19]. The nomenclature 18650 means that the cell is 18 mm
diameter by 65 mm in length. However, there are many other small cylindrical cells being produced such as
32330 (32 mm diameter × 330 mm length) produced by A123 and the 18 mm by 36 mm by 65 mm (same size
as two 18650 cells side by side) cells produced by Boston-Power. [16]
Figure 4: Li-Ion cell formats: small and large cylindrical, pouch, and prismatic. [18]
The benefit of the cylindrical cell is that it uses a tubular can which offers a high-strength packaging
requiring a lot of energy to damage it[20]. One disadvantage is that the cylindrical cells have much higher
initial impedance than a comparative prismatic or polymer type cell. Thismeans thatmore heat is generated,
and the pack must be air cooled[16] .
Prismatic-type cells use a steel, plastic or aluminium can in a rectangular shape. They require less "pack
hardware" and offer high capacity ratings. There are fewer cell-to-cell connections that need to be made so
the reliability is expected to be higher. They are primarily used for electric powertrains in hybrid and electric
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vehicles. However, these cells can be more expensive to manufacture, less efficient in thermal management
and have a shorter cycle life than the cylindrical design[20].
Pouch cells use a soft polymer laminate casing. It is easy to createmany size variations of this cell, making
it relatively easier to design into unique pack solutions. They achieve 90–95 percent packaging efficiency, the
highest among battery packs. As there is no metal enclosure around each cell, it reduces the weight of the
battery pack, but the cell needs support and allowance to expand in the battery container[20]. It is necessary
to design the cells into modules that can manage the “stack pressure” of the cells. These cells perform better
over their lifetime if a consistent uniform pressure is applied over the face of the cell. If the pressure is not
applied uniformly, it can affect the cell’s ability to pass the lithium-ions back and forth within the cell and
eventually cause them to begin getting stuck. This is known as lithium plating and when the lithium-ions
become fixed; this increases the impedance of the cell and reduces the cell life[16].
Most of the auto manufacturers use either large rectangular or cylindrical prismatic cells or flat pouch
cells. Small quantity of cells is required to achieve the voltage and energy needed when using a larger cell and
therefore less potential areas of failures in assemblies of small cells[16].
3.4 Lithium Ion Chemistries
There are many lithium ion chemistries that are available today and are named based on the composition of
the cathode. They include:[18]
• LiCoO2: Lithium cobalt oxide
• LiMnNiCo: Lithiummanganese nickel cobalt
• LiFePO4: Nano-phosphate/lithium iron phosphate
• Li2MnO4: Lithiummanganate
• Li4Ti5O12: Lithium-titanate
• LiPo: Lithium polymer
• LiNiO2: Lithium-nickel-oxide
Figure 5: A comparison of different lithium ion cell chemistries [11]
Let’s now delve into how the cell chemistry was selected. Considering that this will be MUR’s first ever
electric car, safety is extremely important as inexperience andunsafe practices are a recipe for disaster. Indeed,
safety takes precedence over the performance of the car because whatever you do, you do not want a fire or
an explosion that could damage and hurt personnel or property.
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Lithium cobalt oxide is most commonly used in hand-held electronics and offers generally higher energy
density and long cycle life although it is expensive, suffers from being less stable at higher temperatures and
more reactive than other chemistries. Thismeans that at about 130 °C the cell will enter the thermal runaway
stage which is much lower than other lithium-ion chemistries.[16]
Lithiummanganese nickel cobalt (LiMnNiCo) shows a relatively high nominal voltage of about 3.6–3.8
V per cell and has one of the highest energy densities in a production cell today[16]. These cells can have
either a high specific energy or high specific power but not both [21] and since we require a combination of
both for our race car. This is not a suitable choice.
Lithiummanganate offers high energy andhigh power, however, it suffers froma shorter cycle life. Thus,
making it an appropriate chemistry to beused inportable power applicationswhere a long run time is needed
but not necessarily in automotive applications where a long life is also a consideration[16].
Lithium iron phosphate offers high usable energy and is very abuse tolerant. These cells have a nominal
voltage of 3.3V and an operating voltage range between 2.0V and 3.6V. This is lower than other chemistries
such as lithiummanganate (4.2V) or lithium polymer (3.7V, 4.2V). The lower voltage of Lithium iron phos-
phatemeans that more cells are needed in series to achieve a given system voltage, and the watt-hour content
is correspondingly lower for a given amp-hour capacity[14].
Figure 6: Gases released during a thermal runaway: A comparison [22]
Lithium iron phosphate is significantly more stable than other cathode materials and offers the highest
safety of the common cathode materials. The temperature at which thermal runaway occurs with LiFePO4
material is higher than transition metal oxide-based cathodes, and the amount of energy evolved during
cathode decomposition is lower. The amount of produced gas and the percentage of toxic CO (4%) in the
gas is also the lowest for any cell chemistry. [22] The reduced energy density of LiFePO4 also has another
implication; that an LiFePO4-based system will be larger and heavier than if other cathode materials were
used[14].
Thus, Lithium iron phosphate had the desired properties that were needed for this project and it was
not as expensive as lithium titanate or suffered from performance issues in high temperature like lithium
manganate. If a lithium polymer or a lithiummanganate cell had been selected, the battery pack would have
been smaller in size and hence be easier to fit in the car from a mechanical point of view, but it was decided
that safety took top priority.
3.5 Lithium Iron Phosphate (LiFePO4)
Lithium ironphosphate is oneof themost commonchemistries in automotive applicationsbecause it cande-
liver high specific power. It can accept a regenerative braking charge and canprovide an accelerationdischarge
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veryquickly. The other reason thatLiFePO4 is frequently used is due to its relatively low cost. LiFePO4 has
lower energy density than the other chemistries on the market and that means that there is less energy to
discharge in the event of a failure. This results in it being more tolerant of abusive conditions such as over-
charging the cell and high temperatures[16].
Lithium iron phosphate has an extremely flat voltage discharge profile over much of the useful SOC
range. The flatness of the curve is due to the formation of a two-phase mixture during discharge rather than
a continuous reduction in lithium concentration[14].
Figure 7: Schematic of a lithium iron phosphate cell. Each lithium-ion cell consists of an anode and a cath-
ode separated by an electrolyte containing dissociated lithium salts, which enables transfer of lithium ions
between the two electrodes. [23]
When the cell is being charged, an external electrical power source injects electrons into the anode while
the cathode gives up someof its lithium ions at the same time,which thenmove through the electrolyte to the
anode and remain there. During this process, electricity is stored in thebattery in the formof chemical energy.
When the cell is discharging, the lithium ions move back across the electrolyte to the cathode, enabling the
release of electrons to the outer circuit to do the electrical work. [23]
LiFePO4 + 6C −→ LiC6 + FePO4 (1)
The phosphates used in lithium iron phosphate are not prone to thermal runaway and will not burn
even though abuse occurs. Cells made from LiFePO4 have a good shelf life and long cycle life. They are also
maintenance free and are environmentally friendly compared to other cell chemistries as they do not contain
heavy metals[12].
3.6 A123’s AMP20M1HD-A
We selected A123’s AMP20M1HD-A rectangular pouch cell. This cell can provide 19.6Ah, has a nominal
voltage of 3.3V and weighs 496g. It has been abuse tested to satisfy EUCAR’s standards level 3 and 4.
Figure 8: AMP20M1HD-A’s test results [24]
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Figure 9: Hazard levels defined by EUCAR for the use of a battery in an Electric Vehicle. [25]
Level 4 is often considered safe behaviour of the battery as the tests that determine this standard are
considered ‘abusive tests’[25].
As they are pouch cells, they require more design time as the cells need support and must have room to
expand in the battery enclosure. Both cell faces must also be subjected to evenly distributed pressure, while
allowing for cell expansion when fully charged; this will allow the cells to operate at their peak performance
and achieve optimum cycle life[26].
Selecting AMP20M1HD-A also allowed the configuration of the cells in series only (i.e. No cells in par-
allel) because these cells can supply the required current for our car while on track. This greatly simplifies the
design of the accumulator pack and reduces fire risk from electrical shorts. It also enabled the BMS sub-team
to balance the cellsmuchmore effectively and greatly simplifies its complexity. However, there are challenges
in using a series configuration too such as cell matching can be an issue especially when replacing cells in an
old battery pack. This is an issue because old cells generally have less capacity than the new ones and the
overall capacity of a pack made by cells in series is determined by the cell with the lowest capacity. Cell bal-
ancing1while charging and discharging can also be an issue; hencewhy a BatteryManagement System (BMS)
is needed to maximize the capacity of the pack and to ensure the cells are not over-charged/over-discharged.
A123 Systems use Nanophosphate which is a nanoscale lithium ion technology. This material has been
patented and is not offered by any other battery manufacturer. It is designed to maximise the performance
of the cell. This technology has excellent abuse properties. All the lithium ions are transferred during a com-
plete charge/discharge whereas in other metal oxide chemistries only half of the available lithium is trans-
ferred.
Figure 10: Schematic illustration of the “radial model” and structures of LiFePO4 with carbon nan-
otubes/nanorods/nanowires inside illustrated from the cross section. [27]
When such cells are overcharged, it leads to lithium plating on the surface of the anode creating a hazard
1Individual cells can have different capacities due to different internal resistance and some other factors such asmanufacturing
variances or cells from different production runs being mixed together, which results in different levels of State of Charge (SOC).
This means that some cells might reach 100% SOC before the others resulting in charging being stopped and therefore some cells
are still below their maximum capacity; reducing the capacity of the whole pack. So, to be able to use all the pack capacity, these
cells must be brought to the same level of SOC as the other cells in the pack. This is done using various techniques and is referred
to as Cell balancing.
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as metallic lithium is more reactive. Nanophosphate chemistry makes this situation highly unlikely[28].
Moreover, when subjected to abusive conditions, it releases only a small amount of heat and oxygen under
abusive conditions and cells do not exhibit an energetic thermal runaway like other metal oxide lithium
chemistries[28].
Table 3: AMP20M1HD-A’s cell specifications [24]
Specification Value Notes/Comments
Nominal Capacity 20Ah
Minimum Capacity 19.5Ah 25
◦ C, 6A Discharge,
3.6V to 2.0V at BOL
Nominal Voltage 3.3V @50% SOC
Voltage Range 2.0 to 3.6V Fully Discharged to Fully Charged
Absolute Maximum Terminal Voltage 4.0V Above which will causeimmediate damage to the cell
Recommended maximum charge voltage 3.6V
Recommended float charge voltage 3.5V
Recommended end of discharge cutoff 2.0V
Recommended standard charge current 20A to 3.6V
Recommended maximum charge current 100A to 3.6V, Cell temperature < + 85◦ C
Pulse 10s charge current 200A 23◦ C ≤ Tcell< +85◦ C, Vcell < 3.8V
Maximum discharge continuous current 200A 23◦ C ≤ Tcell< + 85◦ C, SOC = 50 %
Pulse 10s discharge current 600A 23◦ C ≤ Tcell < + 85◦ C, SOC = 50 %
Peak 10s Discharge Power 820W SOC=100%, Tcell = 23
◦ C,
Assumed DCR = 2mΩ (nominal)
DCR impedance 1.5 - 3 mΩ 10s, 240A, @ 50% SOC
ACR impedance 0.78 mΩ 1kHz, @ 50% SOC
Operating Temperature Range −30◦ C to +60◦ Ambient around cell
Storage Temperature Range −40◦ C to +65◦
Weight 495 grams ± 10g
Cycle Life to 80% Beginning
of Life (BOL) Capacity 3000 cycles
100% Full DOD cycles,
1C/-2C @ 23◦ C,
8 -14 psi face clamp pressure
4 Safety
Despite being safe relative to other chemistries, LiFePO4 still poses hazards and can be dangerous if proper
care is not taken. The hazards present and their mitigation as well as emergency procedures can be found
in detail in this section. These guidelines were used to prepare official standard operating procedures and
risk analysis forms which were submitted to the university. This not only helped the Accumulator sub-team
but also enabled other sub-teamswithin theMUR-E team to prepare their safety documents and emergency
procedures. Accumulator sub-team also helped the integration sub-team to arrange an Electrical Hazardous
Voltage Safety Course. For this, the accumulator sub-team provided the integration team with a course
outlinewhichwas thenused to arrange anofficial 20-hour hazardous voltage training course at the university.
4.1 Lithium Ion Battery Hazards
Despite the stable chemistry, there are chemical and electrical hazards associated with handling lithium ion
batteries. Although they are designed to withstand considerable amount of abuse, accidents can happen.
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Some of the hazards produced as a result are [29], [26], [25] [24]:
1. This can cause sparks and allow dangerous levels of current as the internal resistance of the battery is
very little. It may also cause arc flashes that can damage property and personnel.
2. This occurs when a cell is charged to a stateof charge greater than 100%. The cell voltage rises and
exceeds the allowable limits of the load device or themonitoring circuit. This causes many irreversible
degradationmechanisms inside the cell which can lead to an energetic failure. This can be a result of a
single severe overcharge event or repeated minor overcharging. Lithium-ion cells can be overcharged
by even very low rates of charge current. Overcharge can lead to thermal runaway, cell swelling, vent-
ing, and other serious events. [14]
3. It is the discharge of a cell beyond 100%depth of discharge (DOD) (0%SOC). Cell voltage falls rapidly
and can even be reversed if the over-discharge current is high enough. This reverse cell potential can
cause failure of management electronics andmalfunctions. Over-discharge can also lead to significant
internal cell damage including dissolution of the anode foil. Any attempts to later recharge a cell that
has been deeply and repeatedly over-discharged can lead to safety risks. [14]
4. Exposure to high temperature increases the rate of cell degradation and can also lead to thermal run-
away, in which the activation temperature of various exothermic chemical reactions inside the cells is
reached and the cell degrades rapidly with a large release of energy, leading to venting of cell contents,
temperature increase, fire, or explosion. Most cells begin to experience higher rates of degradation
above 45°C–55°C and approach safety limitations between 60°C and 100°C. [14]
5. Low temperatures lead to low performance and charging at low temperatures can cause plating of
metallic lithium on the anode leading to irreversible capacity loss and the possibility of metallic “den-
drite” growth, which can penetrate the separator, causing an internal short circuit. Discharge capabil-
ity is also limited under low temperature due to increased cell impedance. [14]
6. Mechanical damage to cells or systems can cause venting or leaking of electrolyte and cell contents,
thermal runaway, or fire and shock hazards due to electric arcing. [14]
7. The probability of most of the failure modes associated with lithium-ion batteries increases with age.
[14]
8. A battery pack with high voltage poses a danger to personnel working on the battery pack.
4.2 Safety Incidents
One of the reason that safety was prioritised over all other design requirements was that there are many
famous stories of Lithium-ion battery packs used in commercial products catching fire. These stories high-
lighted the need for great care in the development of the battery pack. From 2006 to 2008, a series of note-
book computer fires brought to light the danger of a malfunction of even a small group of cells[14]. It led
to a recall of an unprecedented 4.1 million Dell laptops with Sony batteries [30]. The possibility of electric
car fires has been a concern ever since. The introduction of electric vehicles powered by lithium-ion batteries
was accompanied by the thermal events that occurred during crash testing and on-road accidents[14].
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Figure 11: APU Battery from Boeing 787, damaged by thermal event. [31]
On January 7, 2013, a Japan Airlines Boeing 787-8, JA8297 was parked at a gate at Logan International
Airport, Boston, Massachusetts, when maintenance personnel observed smoke coming from the lid of the
auxiliary power unit battery case. No one was injured in the incident, but safety issues related to internal
short circuiting, thermal runaway of cells and manufacturing defects were responsible for the issue[31].
Just last year, a 2014 Tesla Model S caught fire while charging at a supercharger station in Norway[32].
All these incidents were a timely reminder that safety of the battery pack is something that should not be
taken lightly.
Figure 12: Tesla Model S catches fire at a supercharger station in Norway [32]
There were also a couple of incidents relating to the accumulator of FSAE race cars, which are much
more relatable to this project. Both incidents occurred in Europe. In 2016, there was a fire in a hotel during
Formula Student competition inHockenheim,Germanywhere a battery pack belonging to one of the teams
registered in the competition caught fire and left four students injured. [33] The second incident occurred
more recently in 2017where an accumulator pack destroyed two FSAE race cars, an autonomous race car and
part of the workshop where the cars were stored. The damaged done by the fire was estimated to be worth
approximately 250,000 Euros.[34] The team was using a Lithium Polymer type battery instead of Lithium
Ion. Fortunately, no one was hurt during this incident.
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Figure 13: Remaining parts of the FSAE race car after accumulator incident[35]
These fires are mostly a result of not taking safety precautions and not prioritising safety. Lithium-ion
battery chemistries aremuch less tolerant to abusive conditions such as overcharging, over-discharging, over-
temperature, and excessive current than other types of batteries. High-voltage systems always carry a risk of
electric shock as well as the thermal risks associated with battery systems. For this reason, the accumulator
sub-team repeatedly reminded the management team ofMUR-Electric that safety of the battery pack must
be prioritized, and the car should be built around the battery pack rather than the other way round. These
calls were repeatedly ignored but with the help of Prof. Tansu Alpcan, they finally got the message but only
after repeatedly changing the location of the battery pack in the car. Research was also conducted on the
emergency procedures that should be followed if a severe emergency incident occurs. These guidelines are
presented next.
4.3 Emergency Procedures
4.3.1 Hot Cell
A hot cell is a condition that arises because of short circuit of the cell or the battery and it could be internal
or external. The cell or battery temperature rises as this event goes on. (insert another reference here) Some
guidelines for handling a hot cell are: [29]
• Evacuate, and secure the area as soon as a hot cell is detected.
• Monitor the temperature from a safe distance using a non-contact thermometer or thermal imager.
• If temperature monitoring equipment is not available, keep the area evacuated and secure and do not
handle the cell/battery for at least 24-hours.
• If the cell cools, continue to monitor until it reaches ambient temperature.
• Remove the cell from the area once it is cool.
• Dispose of the cell in accordance with waste or recycling protocols.
4.3.2 Vented Cell
Under normal conditions, a cell will not leak or vent however if the cell is overheated or put under excessive
abuse, a cell will vent. Some guidelines for handling this situation are: [26], [29]
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• If the vents are blocked because of an ill designedmechanism, a lithium cell can explode. These events
are rare and are usually because of elevated cell temperatures past it’s critical point.
• In the event of cell emitting smoke or fire, precaution must be taken to limit exposure to these fumes
as they can cause sever irritation to the respiratory tract, eyes and skin. The affected area must be
ventilated immediately and a non-contact means of monitoring and removing the cell must be avail-
able. The cell can then be disposed of according to the hazardous waste disposal procedures of the
university.
• Should a cell explode, all personnel are evacuated and accounted for from the affected area. Ventilation
should be initiated and remain in place until all the smoke is cleared. The area should be cleaned up
by sweeping away the debris and a commercially available solution.
4.3.3 Cell/Battery Disposal
Cells should be recycled where possible. General practises to follow are: [29]
• Secure terminals to prevent short circuiting.
• It must be packaged to prevent shorting with another cell/battery.
• Leaking cells must be packaged in a way that contains the leak.
4.3.4 First Aid Procedures
As the leaking of electrolyte is ahealth hazard. Some first aid measures must be taken. These are: [36]
• If the contents of an open cell are inhaled, source of contaminationmust be removed, or victim should
be moved to open air. Medical advice should be obtained immediately.
• Contact with the contents of an opened cell can cause burns. If eye contact with contents of an open
cell occurs, immediately flush the contaminated eye(s) with lukewarm, gently flowing water for at
least 30 minutes while holding the eyelids open. Neutral saline solution may be used as soon as it is
available. If necessary, continue flushing during transport to emergency care facility. Take care not
to rinse contaminated water into the unaffected eye or onto face. Quickly transport victim to an
emergency care facility.
• Contact with the contents of an opened cell can cause burns. If skin contact with contents of an open
cell occurs, as quickly as possible remove contaminated clothing, shoes and leather goods. Immedi-
ately flush with lukewarm, gently flowing water for at least 30 minutes. If irritation or pain persists,
seek medical attention. Completely decontaminate clothing, shoes and leather goods before reuse or
discard them.
• Contact with the contents of an opened cell can cause burns. If ingestion of contents of an open cell
occurs, never give anything by mouth if victim is rapidly losing consciousness, or is unconscious or
convulsing. Have victim rinse mouth thoroughly with water. Do not induce vomiting. If vomiting
occurs naturally, have victim lean forward to reduce risk of aspiration. Have victim rinse mouth with
water again. Quickly transport victim to an emergency care facility.
4.3.5 Fire Fighting Measures
Lithium ionbatteries contain flammable liquid electrolytewhichmay spark, ignite or cause fire. Electrostatic
discharges imposed directly on the spilled electrolyte may start combustion.
• In case of small fires, Dry chemical, CO2, water spray or regular foam extinguisher can be used. [36]
Page 22
Accumulator
• In case of large fires, clear personnel from the area immediately and move containers from fire area if
possible to do so without risk. Fire must be fought from a distance and done by professionals.[36]
4.3.6 Personal Protective Equipment:
Appropriate personal protective equipmentmust bewornwhileworking/handling cells and batteries. They
are as follows: [37], [2]
• Face shield/Hard hat
• Insulated tools
• Multimeter with protected probe tips
• HV insulating gloves
• Rubber foot mats
• Safety glasses with side shields
• Insulation blankets
• Toe capped boots
• Buddy system
Keeping these guidelines inmind, the accumulator sub-team spent a lot of time conducting risk analysis
and developing standard operating procedures so that not only now but for the future Accumulator team
as well, safe practises and safety is always prioritised. These documents were first prepared and reviewed
internally within the accumulator sub-team and then the integration sub-team reviewed them before being
discussed in detail by a committee of OH&S staff members of the university. Then, finally these documents
were revised one final time before being approved by the university. Some of the standards followed in
preparation of these documents are:
• AS 4836 - Safe working on or near low-voltage electrical installations and equipment
• SA TR ISO 8713:2014 - Electrically propelled road vehicles - Vocabulary
• NCOP 14 - National Guidelines for The Installation Of Electric Drives InMotor Vehicles
• IEC 62133 - Battery Safety Testing
• UL 1642 - Standard for Lithium Batteries (Cells)
• SAE J 1797 - Recommended Practice for Packaging of Electric Vehicle Battery Modules
• SAE J 2344 - Guidelines for Electric Vehicle Safety
These documents will be presented next.
Page 23
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ty.u
n
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.e
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u
.au
 
H
EA
LTH
 A
 SA
FETY: TA
SK
 R
ISK
 A
N
A
LYSIS (TR
A
) FO
R
M
 1
 
D
ate: Ju
n
e 2
0
1
5
 V
ersio
n
: 1.0
 A
u
th
o
rize
d
 b
y: A
sso
ciate D
irecto
r, H
ea
lth
 &
 Safety N
ext R
eview
: Ju
n
e 2
0
1
8
 
©
 Th
e U
n
iversity o
f M
elb
o
u
rn
e –
 U
n
co
n
tro
lled
 w
h
e
n
 p
rin
te
d
. 
 
H
EA
LTH
 &
 SA
FETY 
TA
SK
 R
ISK
 A
N
A
LYSIS (TR
A
) FO
R
M
 
 
R
a N
o
.: 1
.1
 
D
ate
: 2
2
 A
u
g
u
st 2
0
1
7
 
V
e
rsio
n
 N
o
.: 1
.0
 
R
e
vie
w
 D
ate
: A
p
r
il 2
0
1
8
 
A
u
th
o
rise
d
 b
y: D
r
a
g
a
n
 N
e
sic 
 
STEP
 1
 – EN
TER
 IN
FO
R
M
A
TIO
N
 A
B
O
U
T TH
E A
C
T
IV
ITY
/TA
SK
, IT
S LO
C
A
TIO
N
 A
N
D
 T
H
E P
EO
P
LE C
O
M
P
LETIN
G
 TH
E R
ISK
 A
SSESSM
EN
T
 
 
Lo
catio
n
 n
am
e
: 
D
n
B
 
B
u
ild
in
g N
o
.: 
1
7
3
 
R
o
o
m
 N
o
.: 
G
3
0
 
A
sse
sse
d
 b
y: 
M
U
R
 A
C
C
 T
eam
 
H
SR
/Em
p
lo
ye
e
 re
p
re
se
n
tative
: 
D
ean
n
a S
tran
g
is 
D
e
scrip
tio
n
 o
f activity/task: 
W
o
rkin
g w
ith
 an
d
 testin
g a sin
gle
 cell w
h
ich
 w
ill b
e u
sed
 fo
r th
e accu
m
u
lato
r an
d
 its sto
rage. C
h
arge an
d
 d
isch
arge test in
clu
d
in
g vo
ltage, cu
rren
t an
d
 tem
p
e
ratu
re m
easu
rem
en
t at u
p
 to
 2
0
0
A
 an
d
 vo
ltage u
p
 to
 
3
.6
V
. 
W
o
rkp
lace
 co
n
d
itio
n
s (D
e
scrib
e
 layo
u
t an
d
 p
h
ysica
l co
n
d
itio
n
s - in
clu
d
in
g acce
ss an
d
 e
gre
ss) 
A
 safe, se
p
arate w
o
rksp
ace w
h
e
re o
n
ly th
e ap
p
ro
ved
 M
U
R
 team
 m
em
b
ers are allo
w
ed
 access. A
n
 area w
ith
 restricted
 access w
ill b
e req
u
ire
d
 fo
r safe sto
rage
 o
f th
e
 cell after w
o
rk h
as b
e
en
 fin
ish
ed
 b
y th
e 
accu
m
u
lato
r team
. W
o
rksp
ace m
u
st b
e d
ry, in
su
lated
 an
d
 free o
f sh
arp
 o
b
jects. First aid
 kits an
d
 fire extin
gu
ish
ers m
u
st b
e availab
le
 o
n
 site. 
 List syste
m
s o
f w
o
rk fo
r th
e
 activity/task: 
●
 Train
in
g 
●
 In
sp
ectio
n
s 
●
 SO
P
s 
●
 Existin
g co
n
tro
ls 
●
 Em
ergen
cy situ
atio
n
s 
Safety P
ro
to
co
ls an
d
 Em
ergen
cy M
an
agem
e
n
t P
lan
 m
u
st b
e availab
le in
 a visib
le/easily accessib
le p
lace. 
In
sp
ectio
n
 o
f th
e w
o
rkp
lace fo
r h
azard
s an
d
 d
an
ge
rs b
efo
re startin
g th
e cell test. 
A
p
p
ro
p
riate P
P
E to
 p
ro
tect th
e M
U
R
 m
em
b
ers fro
m
 in
ju
ry. 
W
o
rkin
g alo
n
e is p
ro
h
ib
ite
d
. A
t le
ast 2
 M
U
R
 m
em
b
ers w
h
o
 h
ave h
ad
 H
igh
 vo
ltage safety train
in
g m
u
st b
e p
re
sen
t b
efo
re w
o
rk 
w
ith
 th
e cell can
 b
e
gin
. 
R
egu
lar safe
ty d
rills w
ill b
e co
n
d
u
cted
 to
 en
su
re every team
 m
em
b
er kn
o
w
s h
is ro
le in
 case o
f an
 e
m
ergen
cy. 
In
su
lated
 to
o
ls m
u
st b
e u
se
d
. 
C
o
n
d
u
ctive m
aterials (jew
elry etc.) m
u
st n
o
t b
e w
o
rn
 b
y p
erso
n
n
el h
an
d
lin
g cells an
d
 b
atterie
s. 
 
Is th
e
re
 p
ast e
xp
e
rie
n
ce
 w
ith
 th
e
 activity/task th
at m
ay assist in
 th
e
 
asse
ssm
e
n
t? 
●
 Existin
g co
n
tro
ls 
 
●
 SO
P
s 
 
 
●
 Stan
d
ard
s 
●
 In
d
u
stry stan
d
ard
s 
●
 In
cid
e
n
ts &
 n
ear-h
its 
●
 Legislatio
n
 &
 
C
o
d
es 
●
 Train
in
g 
 
●
 In
cid
e
n
t In
ve
stigatio
n
 
●
 G
u
id
an
ce m
aterial 
Train
in
g: A
ll m
em
b
ers h
ave co
m
p
leted
 th
e O
H
S in
d
u
ctio
n
 req
u
ire
d
 b
y th
e EEE d
ep
artm
e
n
t to
 d
o
 th
e
 EEE w
o
rksh
o
p
s an
d
 h
ave 
also
 co
m
p
leted
 2
0
 h
o
u
rs o
f H
azard
o
u
s V
o
ltage Train
in
g o
rgan
ize
d
 b
y M
U
R
. 
SO
P
s: C
ell Testin
g, A
ccu
m
u
lato
r assem
b
ly an
d
 testin
g, Sw
ap
p
in
g o
u
t d
am
age
d
 cells, H
o
t C
ell H
an
d
lin
g. 
Legislatio
n
: O
ccu
p
atio
n
al H
ealth
 an
d
 Safety A
ct 2
0
0
4
 (V
ic), O
ccu
p
atio
n
al H
ealth
 an
d
 Safety R
e
gu
latio
n
s 2
0
0
7
 (V
ic) 
Stan
d
ard
s: SA
 TR
 ISO
 8
7
1
3
:2
0
1
4
, N
C
O
P
 1
4
, IEC
 6
2
1
3
3
 B
attery Safety Testin
g, U
L 1
6
4
2
 Stan
d
ard
 fo
r Lith
iu
m
 B
atteries (C
e
lls), SA
E 
J 1
7
9
7
 R
eco
m
m
en
d
ed
 P
ractice fo
r P
ackagin
g o
f Electric V
eh
icle B
attery M
o
d
u
les, SA
E J 2
3
4
4
 G
u
id
elin
es fo
r Electric V
eh
icle 
Safety 
 
 
 
Accumulator
4.4 Risk Analysis
4.4.1 Single Cell Testing
This document covers all the steps involved in single cell testing and charging. Each step has associated risks
which are then assigned a risk rating, before setting up proper controls for the task and finally calculating a
newrisk rating.
Page 24
safe
ty.u
n
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.e
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H
EA
LTH
 A
 SA
FETY: TA
SK
 R
ISK
 A
N
A
LYSIS (TR
A
) FO
R
M
 3
 
D
ate: Ju
n
e 2
0
1
5
 V
ersio
n
: 1.0
 A
u
th
o
rize
d
 b
y: A
sso
ciate D
irecto
r, H
ea
lth
 &
 Safety N
ext R
eview
: Ju
n
e 2
0
1
8
 
©
 Th
e U
n
iversity o
f M
elb
o
u
rn
e –
 U
n
co
n
tro
lled
 w
h
e
n
 p
rin
te
d
. 
 
STEP
 3
 – ID
EN
TIFY
 H
A
ZA
R
D
S A
N
D
 A
SSO
C
IA
TED
 R
ISK
 R
A
TIN
G
S A
N
D
 C
O
N
TR
O
LS 
Fo
r each
 ste
p
 in
 th
e task: 
• 
B
reak d
o
w
n
 th
e task in
to
 m
an
age
ab
le ste
p
s. List th
e ste
p
s in
 th
e o
rd
er th
at th
ey o
ccu
r; 
• 
Id
en
tify th
e h
azard
(s) asso
ciated
 w
ith
 each
 ste
p
; 
• 
D
eterm
in
e an
d
 reco
rd
 a raw
 risk sco
re
 b
y refere
n
cin
g th
e tw
o
-variab
le risk m
atrix o
r th
e th
ree-variab
le calcu
lato
r; 
• 
P
ro
vid
e a co
n
tro
l d
e
scrip
tio
n
 fo
r each
 cu
rren
t o
r p
ro
p
o
sed
 risk co
n
tro
l; 
• 
Sp
ecify th
e risk co
n
tro
l typ
e
, fo
r each
 cu
rren
t o
r p
ro
p
o
sed
 risk co
n
tro
l; 
• 
W
h
ere p
ro
p
o
se
d
 risk co
n
tro
l(s) h
ave b
ee
n
 id
e
n
tified
 co
m
p
lete an
 H
e
alth
 &
 Safe
ty A
ctio
n
 P
lan
; 
• 
D
eterm
in
e an
d
 reco
rd
 th
e re
sid
u
al risk sco
re
 b
y refe
ren
cin
g th
e tw
o
-variab
le risk m
atrix o
r th
e th
ree-variab
le risk calcu
lato
r. 
H
ie
rarch
y o
f C
o
n
tro
l (C
o
n
tro
l Typ
e
) 
El – Elim
in
atio
n
 
S – Su
b
stitu
tio
n
 
En
 – En
gin
eerin
g 
Is – Iso
latio
n
 
G
 – G
u
ard
in
g 
Sh
 – Sh
ield
in
g 
A
 – A
d
m
in
istrative
 
T – Train
in
g 
In
 – In
sp
ectio
n
 
M
 – M
o
n
ito
rin
g 
H
 – H
ealth
 M
o
n
ito
rin
g 
P
 – P
P
E 
 
C
A
TEG
O
R
Y
 –
 S
T
EP
S IN
 TH
E T
A
SK 
H
A
ZA
R
D
S 
R
A
W
 
R
ISK
 S
C
O
R
E 
C
O
N
TR
O
L D
ESC
R
IP
T
IO
N
 
(C
U
R
R
EN
T
 A
N
D
 P
R
O
P
O
SED) 
C
O
N
TR
O
L T
Y
P
E 
R
ESID
U
A
L 
R
ISK
 S
C
O
R
E 
C
ell Testin
g
 
Tran
sp
o
rt o
f th
e cell fro
m
 sto
rage to
 th
e w
o
rkp
lace 
an
d
 vice versa; 
 
Freq
u
en
t h
an
d
lin
g m
igh
t cau
se electric 
sp
arks o
r a fire b
ecau
se o
f accid
en
tal sh
o
rt 
circu
its; 
R
o
u
gh
 h
an
d
lin
g o
r excessive sh
o
ck an
d
 
vib
ratio
n
; 
C
ell is p
h
ysically cru
sh
ed
 o
r p
u
n
ctu
red
; 
 
1
0
 x 3
 x 
2
5
 = 7
5
0
 
V
ery H
igh
 
 
D
ro
p
p
ed
 ce
ll sh
o
u
ld
 b
e treated
 as a p
o
ten
tial h
o
t cell. See 'H
o
t C
ell 
H
an
d
lin
g' SO
P
. 
C
ell sh
o
u
ld
 b
e in
sp
ected
 fo
r p
h
ysical d
am
age. A
ll in
sp
ectio
n
 to
o
ls 
m
u
st b
e n
o
n
-co
n
d
u
ctive o
r co
vered
 w
ith
 a n
o
n
-co
n
d
u
ctive 
m
aterial. 
C
ell sh
o
u
ld
 b
e m
o
ved
 in
 a tray/p
u
sh
 cart to
 red
u
ce th
e p
ro
b
ab
ility 
o
f d
ro
p
p
in
g. 
C
ell sh
o
u
ld
 b
e fu
sed
 at th
e term
in
als. 
Is, M
 
 In
 
 A
, El 
En
 
1
0
 x 0
.5
 x 
1
5
 = 7
5
 
Lo
w
 
D
isch
argin
g th
e cell 
A
ccid
en
tal sh
o
rtin
g o
f term
in
als w
h
ile 
co
n
n
ectin
g th
e cell term
in
als to
 lo
ad
 
co
n
n
ecto
r; 
Sen
so
rs 
o
n
 
th
e 
term
in
als 
if 
n
o
t 
clam
p
ed
 
p
ro
p
erly can
 lo
o
se
n
 an
d
 cau
se sp
arks; 
1
0
 x 3
 x 
2
5
 = 7
5
0
 
V
ery H
igh
 
C
ell vo
ltage sh
o
u
ld
 b
e m
o
n
ito
re
d
 an
d
 it sh
o
u
ld
 n
o
t b
e allo
w
ed
 to
 
b
e d
isch
arge
d
 b
elo
w
 m
an
u
factu
rer reco
m
m
en
d
e
d
 lim
it. 
C
are m
u
st b
e take
n
 w
h
en
 co
n
n
ectin
g th
e lo
ad
 to
 th
e ce
ll term
in
als. 
Th
is p
ro
cess m
u
st b
e d
o
n
e p
ru
d
e
n
tly. 
Sen
so
rs m
u
st b
e clam
p
e
d
 p
ro
p
erly an
d
 in
sp
ecte
d
 b
efo
re b
egin
n
in
g 
th
e d
isch
arge test. 
B
u
d
d
y system
 m
u
st b
e u
se
d
. 
M
 
 In
 
 En
 
T, In
 
1
0
 x 0
.5
 x 
1
5
 = 7
5
 
Lo
w
 
C
h
argin
g th
e cell 
O
verch
argin
g m
ay lead
 to
 th
e
rm
al ru
n
aw
ay; 
A
ccid
en
tal sh
o
rtin
g o
f term
in
als; 
1
0
 x 3
 x 
2
5
 = V
ery 
H
igh
 
C
ell vo
ltage m
u
st b
e m
o
n
ito
red
 an
d
 ch
argin
g m
u
st b
e sto
p
p
ed
 as 
so
o
n
 as th
e cell reach
es m
an
u
factu
rer reco
m
m
en
d
e
d
 ch
arge 
vo
ltage. 
C
o
rrect p
o
larity sh
o
u
ld
 b
e ap
p
lie
d
 acro
ss th
e ce
ll term
in
als. 
B
u
d
d
y system
 m
u
st b
e u
se
d
. 
M
 
 In
, El 
T, In
 
1
0
 x 0
.5
 x 
1
5
 = 7
5
 
Lo
w
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Accumulator
Page 25
safe
ty.u
n
im
elb
.e
d
u
.au
 
H
EA
LTH
 A
 SA
FETY: TA
SK
 R
ISK
 A
N
A
LYSIS (TR
A
) FO
R
M
 1
 
D
ate: Ju
n
e 2
0
1
5
 V
ersio
n
: 1.0
 A
u
th
o
rize
d
 b
y: A
sso
ciate D
irecto
r, H
ea
lth
 &
 Safety N
ext R
eview
: Ju
n
e 2
0
1
8
 
©
 Th
e U
n
iversity o
f M
elb
o
u
rn
e –
 U
n
co
n
tro
lled
 w
h
e
n
 p
rin
te
d
. 
 
H
EA
LTH
 &
 SA
FETY 
TA
SK
 R
ISK
 A
N
A
LYSIS (TR
A
) FO
R
M
 
 
R
a N
o
.: 2
.1
 
D
ate
: 2
2
 A
u
gu
st 20
1
7 
V
e
rsio
n
 N
o
.: 1
.0
 
R
e
vie
w
 D
ate
: A
p
ril 2
0
1
8
 
A
u
th
o
rise
d
 b
y: D
ragan
 N
e
sic 
 
STEP
 1
 – EN
TER
 IN
FO
R
M
A
TIO
N
 A
B
O
U
T TH
E A
C
T
IV
ITY
/TA
SK
, IT
S LO
C
A
TIO
N
 A
N
D
 T
H
E P
EO
P
LE C
O
M
P
LETIN
G
 TH
E R
ISK
 A
SSESSM
EN
T
 
 
Lo
catio
n
 n
am
e
: 
D
n
B
 
B
u
ild
in
g N
o
.: 
1
7
3 
R
o
o
m
 N
o
.: 
G
3
0
 
A
sse
sse
d
 b
y: 
M
U
R
 A
C
C
 team
 
H
SR
/Em
p
lo
ye
e
 re
p
re
se
n
tative
: 
D
ean
n
a Stran
gis 
D
e
scrip
tio
n
 o
f activity/task: 
H
an
d
lin
g, Testin
g, A
ssem
b
lin
g an
d
 D
isassem
b
lin
g a H
azard
o
u
s V
o
ltage B
attery P
ack (4
0
0
V
, 2
0
0
A
) an
d
 its in
tegratio
n
 in
 th
e car. 
W
o
rkp
lace
 co
n
d
itio
n
s (D
e
scrib
e
 layo
u
t an
d
 p
h
ysica
l co
n
d
itio
n
s - in
clu
d
in
g acce
ss an
d
 e
gre
ss) 
A
 safe, se
p
arate w
o
rksp
ace w
h
e
re o
n
ly th
e ap
p
ro
ved
 M
U
R
 team
 m
em
b
ers are allo
w
ed
 access. A
n
 area w
ith
 restricted
 access w
ill b
e req
u
ire
d
 fo
r safe sto
rage o
f th
e
 b
attery segm
e
n
ts after w
o
rk h
as b
een
 fin
ish
e
d
 
b
y th
e accu
m
u
lato
r team
. W
o
rksp
ace m
u
st b
e d
ry, in
su
lated
 an
d
 free o
f sh
arp
 o
b
jects. First aid
 kits an
d
 fire extin
gu
ish
ers m
u
st b
e availab
le o
n
 site. 
 List syste
m
s o
f w
o
rk fo
r th
e
 activity/task: 
●
 Train
in
g 
●
 In
sp
ectio
n
s 
●
 SO
P
s 
●
 Existin
g co
n
tro
ls 
●
 Em
ergen
cy situ
atio
n
s 
Safety P
ro
to
co
ls an
d
 Em
ergen
cy M
an
agem
e
n
t P
lan
 m
u
st b
e availab
le in
 a visib
le/easily accessib
le p
lace. 
In
sp
ectio
n
 o
f th
e w
o
rkp
lace fo
r h
azard
s an
d
 d
an
ge
rs b
efo
re w
o
rkin
g o
n
 th
e b
attery. 
A
p
p
ro
p
riate P
P
E to
 p
ro
tect th
e M
U
R
 m
em
b
ers fro
m
 in
ju
ry. 
W
o
rkin
g alo
n
e is p
ro
h
ib
ite
d
. A
t le
ast 2
 M
U
R
 m
em
b
ers w
h
o
 h
ave h
ad
 M
U
R
 H
azard
o
u
s V
o
ltage an
d
 Safe W
o
rk Train
in
g m
u
st b
e 
p
resen
t b
efo
re w
o
rk o
n
 th
e b
atte
ry can
 b
egin
. 
In
su
lated
 to
o
ls m
u
st b
e u
se
d
. 
C
o
n
d
u
ctive m
aterials (jew
ellery e
tc.)m
u
st n
o
t b
e w
o
rn
 b
y p
erso
n
n
el h
an
d
lin
g cells an
d
 b
atteries. 
R
efer to
 SO
P
 an
d
 in
d
u
ctio
n
 d
o
cu
m
en
t fo
r em
ergen
cy p
rep
are
d
n
e
ss. 
 
Is th
e
re
 p
ast e
xp
e
rie
n
ce
 w
ith
 th
e
 activity/task th
at m
ay assist in
 th
e
 
asse
ssm
e
n
t? 
●
 Existin
g co
n
tro
ls 
 
●
 SO
P
s 
 
 
●
 Stan
d
ard
s 
●
 In
d
u
stry stan
d
ard
s 
●
 In
cid
e
n
ts &
 n
ear-h
its 
●
 Legislatio
n
 &
 
C
o
d
es 
●
 Train
in
g 
 
●
 In
cid
e
n
t In
ve
stigatio
n
 
●
 G
u
id
an
ce m
aterial 
Train
in
g: A
ll m
em
b
ers h
ave co
m
p
leted
 th
e O
H
S in
d
u
ctio
n
 req
u
ire
d
 b
y th
e EEE d
ep
artm
e
n
t to
 d
o
 th
e
 EEE w
o
rksh
o
p
s an
d
 h
ave 
also
 co
m
p
leted
 2
0
 h
o
u
rs o
f H
azard
o
u
s V
o
ltage Train
in
g o
rgan
ize
d
 b
y M
U
R
. 
SO
P
s: C
ell Testin
g, A
ccu
m
u
lato
r assem
b
ly an
d
 testin
g, Sw
ap
p
in
g o
u
t d
am
age
d
 cells. 
Legislatio
n
: O
ccu
p
atio
n
al H
ealth
 an
d
 Safety A
ct 2
0
0
4
 (V
ic), O
ccu
p
atio
n
al H
ealth
 an
d
 Safety R
e
gu
latio
n
s 2
0
1
7
 (V
ic) 
Stan
d
ard
s: SA
 TR
 ISO
 8
7
1
3
:2
0
1
4
, N
C
O
P
 1
4
, IEC
 6
2
1
3
3
 B
attery Safety Testin
g, U
L 1
6
4
2
 Stan
d
ard
 fo
r Lith
iu
m
 B
atteries (C
e
lls), SA
E 
J 1
7
9
7
 R
eco
m
m
en
d
ed
 P
ractice fo
r P
ackagin
g o
f Electric V
eh
icle B
attery M
o
d
u
les, SA
E J 2
3
4
4
 G
u
id
elin
es fo
r Electric V
eh
icle 
Safety 
 
 
 
Accumulator
4.4.2 High(Hazardous) Voltage
This document details all the steps in assembling a segment or accumulator container that expose personnel
to hazardous voltages. This is themost important safety document and it was critical to get this right. Conse-
quently, theMelbourneUniversity’sOH&S team spent a lot of time reviewing this document alongwith the
Accumulator and Integration sub-teams.
Page 26
safe
ty.u
n
im
elb
.e
d
u
.au
 
H
EA
LTH
 A
 SA
FETY: TA
SK
 R
ISK
 A
N
A
LYSIS (TR
A
) FO
R
M
 3
 
D
ate: Ju
n
e 2
0
1
5
 V
ersio
n
: 1.0
 A
u
th
o
rize
d
 b
y: A
sso
ciate D
irecto
r, H
ea
lth
 &
 Safety N
ext R
eview
: Ju
n
e 2
0
1
8
 
©
 Th
e U
n
iversity o
f M
elb
o
u
rn
e –
 U
n
co
n
tro
lled
 w
h
e
n
 p
rin
te
d
. 
 
STEP
 3
 – ID
EN
TIFY
 H
A
ZA
R
D
S A
N
D
 A
SSO
C
IA
TED
 R
ISK
 R
A
TIN
G
S A
N
D
 C
O
N
TR
O
LS 
Fo
r each
 ste
p
 in
 th
e task: 
• 
B
reak d
o
w
n
 th
e task in
to
 m
an
age
ab
le ste
p
s. List th
e ste
p
s in
 th
e o
rd
er th
at th
ey o
ccu
r; 
• 
Id
en
tify th
e h
azard
(s) asso
ciated
 w
ith
 each
 ste
p
; 
• 
D
eterm
in
e an
d
 reco
rd
 a raw
 risk sco
re
 b
y refere
n
cin
g th
e tw
o
-variab
le risk m
atrix o
r th
e th
ree-variab
le calcu
lato
r; 
• 
P
ro
vid
e a co
n
tro
l d
e
scrip
tio
n
 fo
r each
 cu
rren
t o
r p
ro
p
o
sed
 risk co
n
tro
l; 
• 
Sp
ecify th
e risk co
n
tro
l typ
e
, fo
r each
 cu
rren
t o
r p
ro
p
o
sed
 risk co
n
tro
l; 
• 
W
h
ere p
ro
p
o
se
d
 risk co
n
tro
l(s) h
ave b
ee
n
 id
e
n
tified
 co
m
p
lete an
 H
e
alth
 &
 Safe
ty A
ctio
n
 P
lan
; 
• 
D
eterm
in
e an
d
 reco
rd
 th
e re
sid
u
al risk sco
re
 b
y refe
ren
cin
g th
e tw
o
-variab
le risk m
atrix o
r th
e th
ree-variab
le risk calcu
lato
r. 
H
ie
rarch
y o
f C
o
n
tro
l (C
o
n
tro
l Typ
e
) 
El – Elim
in
atio
n
 
S – Su
b
stitu
tio
n
 
En
 – En
gin
eerin
g 
Is – Iso
latio
n
 
G
 – G
u
ard
in
g 
Sh
 – Sh
ield
in
g 
A
 – A
d
m
in
istrative
 
T – Train
in
g 
In
 – In
sp
ectio
n
 
M
 – M
o
n
ito
rin
g 
H
 – H
ealth
 M
o
n
ito
rin
g 
P
 – P
P
E 
 
C
A
TEG
O
R
Y
 –
 S
T
EP
S IN
 TH
E T
A
SK 
H
A
ZA
R
D
S 
R
A
W
 
R
ISK
 S
C
O
R
E 
C
O
N
TR
O
L D
ESC
R
IP
T
IO
N
 
(C
U
R
R
EN
T
 A
N
D
 P
R
O
P
O
SED) 
C
O
N
TR
O
L T
Y
P
E 
R
ESID
U
A
L 
R
ISK
 S
C
O
R
E 
B
attery P
ack Sto
rage, A
ssem
b
ly &
 In
tegratio
n
 
Tractive system
 co
n
n
ectio
n
s in
 th
e car 
Fatal 
electric 
sh
o
ck 
h
azard
 
d
u
e 
to
 
d
irect 
co
n
tact 
w
ith
 
th
e 
H
igh
 
V
o
ltage 
Tractive 
System
; 
If 
n
o
t 
rated
 
fo
r 
th
e 
h
igh
e
st 
p
o
ssib
le 
co
n
tin
u
o
u
s 
cu
rren
t, 
th
e 
tractive 
system
 
w
irin
g m
ay get to
o
 h
o
t, lo
ss o
f in
su
latio
n
, risk 
to
 
p
erso
n
n
el 
an
d
 
p
o
ten
tial 
d
am
age 
to
 
p
ro
p
erty; 
 
6
 x 3
 x 
1
0
0
 
= 1
8
0
0
 
V
ery H
igh
 
A
ll co
n
n
ectio
n
s sh
o
u
ld
 b
e m
ad
e first; A
ccu
m
u
lato
r co
n
n
ectio
n
 to
 b
e 
m
ad
e last. 
Tractive system
 m
u
st o
n
ly b
e h
an
d
led
 afte
r an
 Electric Safety O
fficer 
gives th
e go
 ah
ead
 an
d
 d
eem
s it safe fo
r h
an
d
lin
g. 
Tractive system
 m
u
st h
ave safety sw
itch
es, A
ccu
m
u
lato
r Iso
latio
n
 
R
elays, H
igh
 V
o
ltage D
isco
n
n
ect an
d
 C
o
n
tacto
rs th
at can
 iso
late th
e 
tractive system
 fro
m
 th
e A
ccu
m
u
lato
r. 
Safety LED
's m
u
st b
e
 in
stalle
d
 o
n
 th
e co
n
tain
er an
d
 aro
u
n
d
 th
e
 w
o
rk 
area th
at tu
rn
 o
n
 if H
igh
 V
o
ltage is p
re
sen
t in
 th
e system
. 
 
El 
 M
, T, In
 
 En
, Is 
 A
, M
 
 
6
 x 0
.1
 x 2
5
 
= 1
5
 
Lo
w
 
D
esign
/M
an
u
factu
rin
g o
f th
e A
ccu
m
u
lato
r 
C
o
n
tain
er 
A
 p
o
o
rly d
esign
e
d
 A
ccu
m
u
lato
r co
n
tain
er: 
• 
m
ay n
o
t cater fo
r cell ven
t leakage 
o
r 
th
e 
co
o
lin
g 
system
 
can
 
fail 
w
h
ich
 
can
 
create 
a 
d
an
gero
u
s 
th
erm
al even
t. 
• 
P
o
o
r 
m
an
u
factu
rin
g 
m
ay 
n
o
t 
p
ro
tect th
e cells an
d
 lead
 to
 an
 
exp
lo
sio
n
. 
• 
In
crease ch
an
ces o
f an
 arc flash
. 
2
 x 3
 x 
1
0
0
 = 6
0
0
 
V
ery H
igh
 
A
ccu
m
u
lato
r segm
en
ts m
u
st b
e d
esign
e
d
 so
 th
at th
ey d
o
 n
o
t co
ver 
th
e cell ve
n
ts. 
In
sp
ectio
n
 
is 
re
q
u
ired
 
b
efo
re
 
th
e 
m
an
u
factu
red
 
sep
arato
r 
is 
co
n
n
ected
 to
 th
e m
o
d
u
le. 
A
ccu
m
u
lato
r co
n
tain
er m
u
st b
e d
esign
ed
 to
 ke
ep
 th
e cell ven
ts fro
m
 
b
ein
g b
lo
cked
. 
A
ccu
m
u
lato
r co
n
tain
er m
u
st b
e su
b
jecte
d
 to
 an
 FEA
 an
alysis b
efo
re 
fin
alisin
g th
e d
esign
. 
A
ccu
m
u
lato
r 
co
n
tain
er 
m
u
st 
m
eet 
th
e 
m
in
im
u
m
 
FSA
E 
req
u
irem
e
n
ts. 
In
 case o
f cell ven
tin
g, if p
o
ssib
le th
e m
o
d
u
le m
u
st b
e
 iso
lated
. If n
o
t, 
th
e p
rio
rity m
u
st b
e to
 evacu
ate th
e p
e
rso
n
n
el an
d
 ve
n
tilate th
e 
w
o
rksp
ace b
y o
p
en
in
g th
e ro
ller d
o
o
rs. 
En
 
 In
 
 En
 
 En
 
En
 
Is 
 
2
 x 0
.1
 x 
1
0
0
 = 2
0
 
Lo
w
 
In
stallin
g co
n
n
ecto
rs to
 th
e accu
m
u
lato
r co
n
tain
er 
C
o
n
n
ecto
rs 
if 
n
o
t 
rate
d
 
fo
r 
th
e 
h
igh
est 
p
o
ssib
le co
n
tin
u
o
u
s cu
rre
n
t can
 cau
se th
e
 
in
su
latio
n
 to
 b
e d
am
aged
 an
d
 m
ake h
an
d
lin
g 
o
f 
th
e 
tractive 
system
 
d
an
gero
u
s 
to
 
p
erso
n
n
el; 
1
 x 3
 x 5
0
 
= 1
5
0
 
M
ed
iu
m
 
C
o
n
n
ectio
n
s m
u
st b
e m
ad
e b
efo
re th
e accu
m
u
lato
r is assem
b
le
d
. 
 Safety LED
's m
u
st b
e in
stalle
d
 o
n
 th
e co
n
tain
er an
d
 aro
u
n
d
 th
e w
o
rk 
area th
at tu
rn
 o
n
 if H
igh
 V
o
ltage is p
re
sen
t in
 th
e system
. 
W
ires m
u
st b
e crim
p
ed
 an
d
 in
sp
e
cted
 acco
rd
in
g to
 th
e crim
p
in
g SO
P
 
2
.2
. 
El 
A
, M
 
 En
, T 
1
 x 0
.5
 x 1
5
 
= 7
.5
 
Lo
w
 
Accumulator
Page 27
safe
ty.u
n
im
elb
.e
d
u
.au
 
H
EA
LTH
 A
 SA
FETY: TA
SK
 R
ISK
 A
N
A
LYSIS (TR
A
) FO
R
M
 4
 
D
ate: Ju
n
e 2
0
1
5
 V
ersio
n
: 1.0
 A
u
th
o
rize
d
 b
y: A
sso
ciate D
irecto
r, H
ea
lth
 &
 SafetyN
ext R
eview
: Ju
n
e 2
0
1
8
 
©
 Th
e U
n
iversity o
f M
elb
o
u
rn
e –
 U
n
co
n
tro
lled
 w
h
e
n
 p
rin
te
d
. 
C
A
TEG
O
R
Y
 –
 S
T
EP
S IN
 TH
E T
A
SK 
H
A
ZA
R
D
S 
R
A
W
 
R
ISK
 S
C
O
R
E 
C
O
N
TR
O
L D
ESC
R
IP
T
IO
N
 
(C
U
R
R
EN
T
 A
N
D
 P
R
O
P
O
SED) 
C
O
N
TR
O
L T
Y
P
E 
R
ESID
U
A
L 
R
ISK
 S
C
O
R
E 
Lo
o
se co
n
n
ectio
n
s w
ill cau
se sp
arks o
r an
 arc 
flash
; 
 
 
A
ssem
b
lin
g th
e m
o
d
u
le
s w
ith
in
 th
e accu
m
u
lato
r 
co
n
tain
er 
A
ccid
en
tal 
in
ter-m
o
d
u
le 
sh
o
rtin
g 
m
igh
t 
cau
se sp
arks; 
M
o
d
u
le is p
h
ysically cru
sh
e
d
; 
 
3
 x 1
 x 5
0
 
= 1
5
0
 
M
ed
iu
m
 
D
ro
p
p
ed
 m
o
d
u
le
s m
u
st b
e iso
lated
 an
d
 m
o
n
ito
red
. 
M
o
d
u
les m
u
st b
e in
sp
ected
 fo
r p
h
ysical d
am
age. A
ll in
sp
ectio
n
 
to
o
ls m
u
st b
e n
o
n
-co
n
d
u
ctive o
r co
vered
 w
ith
 a n
o
n
-co
n
d
u
ctive 
m
aterial. 
M
o
d
u
les m
u
st b
e m
o
ved
 in
 a tray/p
u
sh
 cart to
 red
u
ce th
e 
p
o
ssib
ility o
f d
ro
p
p
in
g. 
M
o
d
u
le te
rm
in
als m
u
st h
ave
 in
su
lated
 co
ver to
 avo
id
 accid
en
tal 
co
n
tact. 
 
Is, M
 
In
 
 El, A
 
En
 
3
 x 0
.1
 x 5
0
 
= 1
5
 
Lo
w
 
 
C
o
n
n
ectin
g th
e m
o
d
u
les in
 th
e accu
m
u
lato
r to
 fo
rm
 
a b
ig b
attery p
ack
 
If 
o
n
e 
o
f 
th
e 
m
o
d
u
les 
w
e
re
 
in
co
rrectly 
o
rien
tate
d
 
d
u
rin
g 
assem
b
ly, 
jo
in
in
g 
th
e
 
m
o
d
u
les can
 cau
se th
erm
al ru
n
aw
ay o
r an
 
arc flash
; 
Freq
u
en
t 
h
an
d
lin
g 
m
igh
t 
cau
se 
electric 
sp
arks o
r a fire b
ecau
se o
f accid
en
tal sh
o
rt 
circu
its. A
n
 arc flash
 cau
se
d
 b
y a sh
o
rt circu
it 
in
vo
lvin
g b
o
th
 h
igh
 vo
ltage an
d
 h
igh
 cu
rren
t, 
em
its 
extrem
ely 
h
igh
 
in
ten
sity 
visib
le 
an
d
 
u
ltra vio
let ligh
t w
ith
 th
e p
o
ten
tial to
 d
am
age 
p
ro
p
erty an
d
 cau
se b
lin
d
n
e
ss an
d
 b
u
rn
s to
 
p
erso
n
n
el. 
 
3
 x 3
 x 
1
0
0
 = 6
0
0
 
V
ery H
igh
 
M
o
d
u
le p
o
sitive an
d
 n
e
gative term
in
als m
u
st b
e clearly m
arke
d
 
b
efo
re assem
b
ly. 
Th
e co
n
n
ectin
g m
o
d
u
le
s m
u
st b
e
 en
gin
eered
 in
 su
ch
 a w
ay th
at th
e 
m
o
d
u
les can
 o
n
ly b
e co
n
n
ecte
d
 in
 th
e co
rrect w
ay. 
V
o
ltage sh
o
u
ld
 b
e te
ste
d
 u
sin
g a m
u
lti-m
eter fro
m
 en
d
 to
 e
n
d
 to
 
en
su
re th
at all se
gm
en
ts are align
ed
 co
rrectly. 
En
, El 
 En
 
 In
 
3
 x 0
.5
 x 1
5
 
= 2
2
.5
 
Lo
w
 
C
arryin
g/M
o
vin
g th
e fu
lly assem
b
led
 A
ccu
m
u
lato
r 
Ergo
n
o
m
ic h
azard
s d
u
e to
 h
eavy w
eigh
t o
f 
th
e accu
m
u
lato
r; 
 
3
 x 3
 x 2
5
 
= 2
2
5
 
M
ed
iu
m
 
A
ccu
m
u
lato
r m
u
st b
e tran
sp
o
rte
d
 o
n
 a ch
arge cart to
 red
u
ce 
ch
an
ce o
f in
ju
ry. 
M
an
u
al h
an
d
lin
g p
ro
ced
u
res to
 b
e fo
llo
w
ed
. M
an
u
al h
an
d
lin
g 
train
in
g m
u
st b
e co
m
p
leted
. 
 
M
 
 A
, El 
 
1
0
 x 0
.5
 x 
1
5
 = 7
5
 
Lo
w
 
C
h
argin
g th
e A
ccu
m
u
lato
r 
O
verch
argin
g m
ay lead
 to
 th
e
rm
al ru
n
aw
ay; 
C
ell ven
tin
g; 
 
6
 x 1
 x 
1
0
0
 = 6
0
0
 
V
ery H
igh
 
A
ccu
m
u
lato
r vo
ltage m
u
st b
e m
o
n
ito
red
 an
d
 ch
argin
g m
u
st b
e 
sto
p
p
e
d
 as so
o
n
 as th
e cell reach
es m
axim
u
m
 m
an
u
factu
rer 
reco
m
m
en
d
ed
 vo
ltage. 
A
ccu
m
u
lato
r m
u
st n
o
t b
e ch
arge
d
 at a rate ab
o
ve m
an
u
factu
rer 
reco
m
m
en
d
ed
 cu
rre
n
t. 
A
ccu
m
u
lato
r co
n
n
ecto
rs m
u
st o
n
ly allo
w
 co
rrect p
o
larity 
co
n
n
ectio
n
. 
In
 case o
f cell ven
tin
g, refer to
 H
o
t cell SO
P
 # 1
.3
. 
M
 
 M
 
 EN
 
M
, En
 
 
6
 x 0
.1
 x 2
5
 
= 1
5
 
Lo
w
 
Accumulator
Page 28
safe
ty.u
n
im
elb
.e
d
u
.au
 
H
EA
LTH
 A
 SA
FETY: TA
SK
 R
ISK
 A
N
A
LYSIS (TR
A
) FO
R
M
 5
 
D
ate: Ju
n
e 2
0
1
5
 V
ersio
n
: 1.0
 A
u
th
o
rize
d
 b
y: A
sso
ciate D
irecto
r, H
ea
lth
 &
 Safety N
ext R
eview
: Ju
n
e 2
0
1
8
 
©
 Th
e U
n
iversity o
f M
elb
o
u
rn
e –
 U
n
co
n
tro
lled
 w
h
e
n
 p
rin
te
d
. 
C
A
TEG
O
R
Y
 –
 S
T
EP
S IN
 TH
E T
A
SK 
H
A
ZA
R
D
S 
R
A
W
 
R
ISK
 S
C
O
R
E 
C
O
N
TR
O
L D
ESC
R
IP
T
IO
N
 
(C
U
R
R
EN
T
 A
N
D
 P
R
O
P
O
SED) 
C
O
N
TR
O
L T
Y
P
E 
R
ESID
U
A
L 
R
ISK
 S
C
O
R
E 
M
o
d
u
le/segm
e
n
t Sto
rage, A
ssem
b
ly &
 In
te
gratio
n
 
C
ell Sto
rage
 
A
ccid
en
tal sh
o
rtin
g o
f term
in
als; 
Excessive h
eatin
g o
r in
cin
eratio
n
; 
C
ell 
is 
p
h
ysically 
cru
sh
ed
 
o
r 
p
u
n
ctu
re
d
 
(p
o
ssib
le ch
em
ical leak); 
1
0
 x 1
 x 
5
0
 = 5
0
0
 
H
igh
 
C
ells m
u
st b
e sto
red
 in
 th
eir o
rigin
al co
n
tain
ers o
r eq
u
ivalen
t; 
C
ells m
u
st b
e sto
red
 acco
rd
in
g to
 m
an
u
factu
rer reco
m
m
en
d
atio
n
s. 
C
ells m
u
st b
e segre
gate
d
 fro
m
 o
th
er co
m
b
u
stib
le
 o
r flam
m
ab
le 
m
aterials. 
 
Is 
Is, M
 
 
1
0
 x 0
.1
 x 
2
5
 = 2
5
 
Lo
w
 
G
en
e
ral H
azard
s w
h
en
 w
o
rkin
g w
ith
 B
attery C
e
lls/ 
segm
e
n
ts 
Electro
cu
tio
n
 
w
h
ere 
vo
ltages 
excee
d
 
LV
 
(FSA
E, >6
0
V
 D
C
 o
r 2
5
V
 R
M
S A
C
); 
Sh
o
rt C
ircu
it; 
 
1
0
 x 1
0
 x 
1
0
0
 = 
1
0
0
0
0
 
V
ery H
igh
 
A
p
p
ro
p
riate P
P
E m
u
st b
e u
sed
 b
e
fo
re h
an
d
lin
g a cell as sp
ecified
 
b
y SO
P
 1
.1
 
Fib
reglass em
ergen
cy h
o
o
k sh
o
u
ld
 b
e easily accessib
le. 
En
su
re th
at th
ere is a first aid
 kit n
earb
y. 
A
ll b
attery/cell w
o
rk m
u
st b
e d
o
n
e w
ith
 at least 2
 p
eo
p
le. 
A
 
Fire 
e
xtin
gu
ish
er 
m
u
st 
b
e
 
availab
le 
as 
reco
m
m
en
d
e
d
 
b
y 
m
an
u
factu
rer. 
A
ccess 
m
u
st 
b
e 
re
stricte
d
 
o
n
ly 
to
 
H
igh
 
V
o
ltage 
safety 
train
e
d
 
p
erso
n
n
el to
 b
o
th
 th
e sto
rage an
d
 th
e w
o
rkp
lace w
h
ere cells are 
b
ein
g assem
b
le
d
. 
W
h
ere 
vo
ltage
s 
e
xcee
d
 
LV
 
(FSA
E) 
H
V
 
safety 
p
ro
ced
u
res 
to
 
b
e 
fo
llo
w
ed
 SO
P
 2
.1
. 
 
P
 
 A
,M
 
 A
, M
 
A
, M
 
A
 
 A
, El 
 
1
0
 x 0
.5
 x 
1
5
 = 7
5
 
Lo
w
 
 
C
o
n
n
ectin
g th
e cells p
h
ysically o
r in
 a h
o
u
sin
g to
 
m
ake a cell m
o
d
u
le/segm
en
t 
A
ccid
en
tal 
in
tercell 
sh
o
rtin
g 
m
igh
t 
cau
se 
sp
arks; 
Electric 
sh
o
ck 
h
azard
s 
b
ecau
se 
o
f 
w
et 
w
o
rksp
ace; 
Freq
u
en
t 
h
an
d
lin
g 
m
igh
t 
cau
se 
electric 
sp
arks o
r a fire b
ecau
se o
f accid
en
tal sh
o
rt 
circu
it o
n
 th
e sam
e cell; 
C
ell is p
h
ysically cru
sh
ed
 o
r p
u
n
ctu
red
; 
O
n
e/ So
m
e cells are o
ld
e
r th
an
 th
e o
th
ers 
an
d
 co
u
ld
 cau
se cell failu
re; 
3
 x 6
 x 5
0
 
= 9
0
0
 
V
ery H
igh
 
Flo
o
rin
g m
u
st h
ave ru
b
b
er m
ats w
h
ere flo
o
rin
g is co
n
d
u
ctive su
ch
 
as co
n
crete flo
o
rs. 
C
ell term
in
als m
u
st b
e in
su
lated
 excep
t ce
ll b
e
in
g w
o
rke
d
 o
n
. 
M
o
d
u
le te
rm
in
als m
u
st b
e in
su
lated
 to
 avo
id
 accid
en
tal co
n
tact. 
D
ro
p
p
ed
 ce
lls m
u
st b
e treate
d
 as p
o
ten
tial h
o
t cells. R
efer SO
P
 1
.3
. 
C
ells m
u
st b
e in
sp
ected
/teste
d
 fo
r p
h
ysical d
am
age. A
ll to
o
ls m
u
st 
b
e n
o
n
-co
n
d
u
ctive o
r co
vered
 w
ith
 a n
o
n
-co
n
d
u
ctive m
aterial. 
C
ells m
u
st n
o
t b
e fo
rced
 in
to
 m
o
d
u
le h
o
u
sin
gs. 
 
A
 
En
 
En
 
Is 
 En
 
G
 
Is, M
 
 A
 
3
 x 1
 x 1
5
 
= 4
5
 
Lo
w
 
C
o
n
n
ectin
g th
e cell tab
s to
 fo
rm
 a serie
s b
attery 
co
n
n
ectio
n
 
P
o
o
r 
d
esign
 
can
 
cau
se 
th
e
 
fo
llo
w
in
g 
electrical/m
ech
an
ical fau
lts an
d
 sh
o
rts: 
If o
n
e o
f th
e cells w
ere in
co
rrectly o
rien
tated
 
d
u
rin
g assem
b
ly, jo
in
in
g th
e tab
s can
 cau
se 
th
e cell to
 o
verh
eat an
d
 lead
 to
 d
an
ge
ro
u
s 
co
n
d
itio
n
s; 
Sh
o
rt circu
itin
g can
 cau
se sp
arks; 
C
ell tab
s can
 b
e d
am
aged
 d
u
e to
 excessive 
b
en
d
in
g; 
3
 x 6
 x 5
0
 
= 9
0
0
 
V
ery H
igh
 
G
o
o
d
 d
esign
 o
f th
e system
 w
ill in
clu
d
e: 
C
ells 
p
o
sitive 
an
d
 
n
e
gative 
term
in
als 
m
u
st 
b
e 
m
arked
 
b
efo
re 
assem
b
ly. 
Extrem
e care m
u
st b
e taken
 w
h
e
n
 co
n
n
ectin
g th
e cell tab
s to
 m
ake 
su
re co
rrect term
in
als are co
n
n
e
cted
. B
u
d
d
y to
 d
o
u
b
le ch
eck. 
C
ell tab
s m
u
st b
e b
en
t carefu
lly an
d
 n
o
t to
o
 acu
tely to
 avo
id
 d
am
age 
to
 th
e cell. 
To
o
ls u
sed
 o
n
 th
e tab
s m
u
st b
e
 in
su
late
d
 to
 m
ake su
re th
at th
e 
term
in
als are n
o
t sh
o
rted
. 
En
 
 A
 
 En
 
 T, In
 
En
 
3
 x 0
.5
 x 1
5
 
= 2
2
.5
 
Lo
w
 
Accumulator
Page 29
safe
ty.u
n
im
elb
.e
d
u
.au
 
H
EA
LTH
 A
 SA
FETY: TA
SK
 R
ISK
 A
N
A
LYSIS (TR
A
) FO
R
M
 6
 
D
ate: Ju
n
e 2
0
1
5
 V
ersio
n
: 1.0
 A
u
th
o
rize
d
 b
y: A
sso
ciate D
irecto
r, H
ea
lth
 &
 Safety N
ext R
eview
: Ju
n
e 2
0
1
8
 
©
 Th
e U
n
iversity o
f M
elb
o
u
rn
e –
 U
n
co
n
tro
lled
 w
h
e
n
 p
rin
te
d
. 
C
A
TEG
O
R
Y
 –
 S
T
EP
S IN
 TH
E T
A
SK 
H
A
ZA
R
D
S 
R
A
W
 
R
ISK
 S
C
O
R
E 
C
O
N
TR
O
L D
ESC
R
IP
T
IO
N
 
(C
U
R
R
EN
T
 A
N
D
 P
R
O
P
O
SED) 
C
O
N
TR
O
L T
Y
P
E 
R
ESID
U
A
L 
R
ISK
 S
C
O
R
E 
Im
p
ro
p
er 
h
an
d
lin
g 
m
igh
t 
cau
se 
electric 
sp
arks o
r a fire b
ecau
se o
f accid
en
tal sh
o
rt 
circu
its; 
Electric sh
o
ck h
azard
s d
u
e to
 w
et w
o
rksp
ace; 
C
lam
p
in
g p
late an
d
 w
ed
ges m
ay h
ave d
efects 
o
r m
ayb
e in
co
rrectly d
esign
e
d
 w
h
ich
 m
ay 
lead
 to
 lo
se co
n
n
ectio
n
s b
etw
e
en
 th
e cell 
tab
s th
at can
 cau
se sp
arks; 
A
ccid
en
tal sh
o
rt circu
its m
igh
t b
e
 cau
sed
 d
u
e 
to
 u
n
in
su
late
d
 to
o
ls o
r o
b
jects fallin
g o
n
 th
e 
co
n
n
ected
 cells; 
Freq
u
en
t h
an
d
lin
g m
igh
t cau
se
 an
 electric 
sh
o
ck 
o
r 
start 
a 
fire 
b
ecau
se 
o
f 
sh
o
rt 
circu
itin
g; 
Electric 
sh
o
ck 
h
azard
s 
b
ecau
se 
o
f 
w
et 
w
o
rksp
ace; 
C
ell sw
e
llin
g an
d
 ru
p
tu
re
 d
u
e to
 exce
ss ce
ll 
p
ressu
re cau
sed
 b
y b
lo
cked
 ven
t h
o
le in
 cell; 
 
C
ells co
n
n
ected
 in
 series m
u
st n
o
t h
ave a cen
tre vo
ltage tap
. 
U
se R
u
b
b
er m
ats w
h
ere req
u
ire
d
 b
y SO
P
s. 
C
lam
p
in
g p
lates an
d
 w
e
d
ges m
u
st b
e
 su
b
jecte
d
 to
 an
 FEA
 an
alysis 
b
efo
re m
an
u
factu
rin
g. 
Th
ey m
u
st b
e m
an
u
factu
red
 carefu
lly an
d
 w
h
ile co
n
stru
ctin
g th
e 
m
o
d
u
le, th
ey m
u
st b
e su
b
jecte
d
 to
 a p
ed
an
tic in
sp
ectio
n
 to
 m
ake 
su
re everyth
in
g fits p
e
rfectly. 
C
ell sep
arato
rs m
u
st b
e d
esign
e
d
 so
 th
at th
ey d
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 n
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t co
ver th
e cell 
ven
ts. 
 
A
 
 En
 
 En
 
 A
, El 
 
M
akin
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n
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s to
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r C
ell B
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cer (e.g. 
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ellp
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 P
o
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erlab
) fro
m
 each
 o
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r 
m
o
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rin
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 cu
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 w
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tact w
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 d
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to
 
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so
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o
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 b
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esign
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/In
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rrectly m
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 B
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ill n
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r th
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 m
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ay lead
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g to
 d
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gero
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r th
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el; 
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 x 1
 x 5
0
 
= 1
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M
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iu
m
 
O
n
ly o
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ire m
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e co
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 ce
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e. 
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ires m
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 m
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 n
ecessary an
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 te
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 m
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rrectly. 
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 secu
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 th
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secu
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erly 
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Sh
 
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, En
 
3
 x 0
.5
 x 1
5
 
= 2
2
.5
 
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w
 
C
h
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n
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ell O
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g lead
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 th
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ay; 
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 x 3
 x 
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V
ery H
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M
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ltage m
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 ch
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g m
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as so
o
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 as th
e cell reach
es m
an
u
factu
rer reco
m
m
en
d
ed
 cell vo
ltage 
x n
u
m
b
er o
f cells (fo
r series co
n
n
ectio
n
). 
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o
d
u
le 
m
u
st 
n
o
t 
b
e 
ch
arge
d
 
at 
to
o
 
h
igh
 
a 
cu
rre
n
t 
an
d
 
reco
m
m
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d
ed
 valu
e b
y th
e m
an
u
factu
rer m
u
st b
e fo
llo
w
ed
. 
C
o
rrect p
o
larity m
u
st b
e
 ap
p
lied
 acro
ss th
e m
o
d
u
le term
in
als. Fo
r 
th
is p
u
rp
o
se, m
o
d
u
le term
in
als m
u
st b
e m
arked
 an
d
 it m
u
st o
n
ly b
e 
p
o
ssib
le to
 co
n
n
ect th
e m
o
d
u
le
s in
 th
e co
rrect w
ay. 
Sen
so
rs w
/feed
b
ack to
 B
M
S &
 co
n
tacto
r; A
d
d
 vo
ltage se
n
so
rs to
 
d
etect im
b
alan
ce, vo
ltage cro
ss-o
ver fro
m
 H
V
 to
 LV
. 
A
 co
n
tacto
r th
at can
 b
reak th
e h
igh
-p
o
w
er circu
it d
u
rin
g an
 eve
n
t, 
su
ch
 as a sh
o
rt-circu
it, h
en
ce p
re-em
p
tin
g a p
o
ten
tial e
xo
th
erm
ic 
even
t. 
M
 
M
 
In
 
In
 
A
 
In
, T, En
 
A
 
Is 
M
, En
 
Is 
P
 
1
0
 x 0
.5
 x 
1
5
 = 7
5
 
Lo
w
 
 
Accumulator
Page 30
safe
ty.u
n
im
elb
.e
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u
.au
 
H
EA
LTH
 A
 SA
FETY: TA
SK
 R
ISK
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 7
 
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ate: Ju
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e U
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iversity o
f M
elb
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e –
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n
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 w
h
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.g. 
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C
ircu
it 
B
reaker) 
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e 
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clu
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 in
 all ch
argin
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its. 
A
 
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isch
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g th
e m
o
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A
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o
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rm
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als 
w
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co
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th
e 
m
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rm
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als 
to
 
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ires n
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 fo
r th
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h
eat u
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 e
xtrem
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B
ecau
se Lith
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m
 cells h
ave a very lo
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tern
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p
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 m
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at can
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se d
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r 
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ry to
 p
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sp
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p
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Accumulator
Page 31
safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 1 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
 
Figure 1: A123’s AMP20M1HD-A LiFePO4 Cell 
 
1. INTRODUCTION 
This Standard Operating Procedure documents 
Melbourne University Racing Accumulator team’s 
approach to the safe management of individual cell 
testing. 
A123’s AMP20M1HD-A uses one of the safest Lithium 
cell chemistries, namely LiFePO4. When lithium iron 
phosphate is used as cathode material, it results in a 
very safe cell. The reason for this is that phosphates can 
withstand high temperatures which results in them 
being very stable as compared to other lithium metal or 
lithium polymer cells during overcharge or short circuit 
conditions. As a single cell can only have a maximum of 
3.6V at the terminals, working with these possesses 
little danger to personnel as compared to Class B (or 
FSAE HV) voltages. 
 
 
 
2. REQUIREMENTS 
2.1 Training/Licensing 
Personnel shall have the following certifications: 
• MUR Hazardous Voltage and Safe Work Training 
2.2 Personal Protective Equipment 
N/A 
2.3 Other 
● Insulated cable shears, screwdrivers and other 
tools 
● Multi-meter with protected probe tips 
 
3. WARNINGS/SPECIAL REQUIREMENTS 
 
There are several risks associated with cell testing. 
These risks can include: 
• burns associated with direct contact; 
• inhalation of toxic gases (due to cell venting). 
 
4. OPERATION 
4.1 Start Up 
• Workspace must be inspected daily before 
starting the testing process to make sure that 
there are no electrical safety hazards. 
Equipment must also be inspected and any 
damaged equipment must be isolated. 
• Written work and training instructions must be 
available for each manufacturing procedure. 
• Work surfaces must be non-conductive. 
• All jewellery must be removed to prevent short 
circuiting the cell. 
• Appropriate personal protective equipment 
must be worn. 
• Cell(s) must be transported in trays or on 
pushcarts to reduce the possibility of dropping. 
• When loading cells during electrical tests, use 
caution not to exceed the current rating of the 
fusing. 
• Ensure that there is a direct egress path to the 
emergency exit. 
 
 
[Melbourne University Racing] 
STANDARD OPERATING PROCEDURE 
[Cell Testing] 
SOP No. 1.1 
 
Date: August 2017 
Review Date: April 2018 
Version No. 1.0 
Authorised by: Dragan Nesic 
 
Accumulator
4.5 Standard Operating Procedures
4.5.1 Cell Testing
This document details the cell testing procedure and should prove invaluable to the next year’s team as when
accumulator sub-team of 2017 started the project, there were no guidelines available on how to go about cell
testing andwhat are thehazards that are involved in this process.
Page 32
safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 2 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
4.2 During Operation 
• Both the surrounding environment and the 
cell’s temperature must be monitored during 
operation to evaluate if a safe operating 
temperature is being maintained. 
• Use a battery management system to monitor 
against over-charge and over-discharge, 
monitor the operating temperature to ensure 
proper cell usage. This prevents abuse of the 
battery pack and extends battery life. 
• Temperature sensor must be connected to the 
negative terminal of the cell. 
• Wires must be connected to one terminal at a 
time. 
• The cell tabs must be clamped after the wires 
are connected. 
• Make sure that the connection between cell tab 
and the wires are not loose after clamping. 
• Make sure the cell tabs and the wires do not 
short, so connect them in a way that keeps a 
gap between the two tabs and keep the cell on 
a clean, steady work desk. 
Discharge: 
• Use the Andersen connector to connect the 
load bank to the cell. 
• Turn on the power to the load bank. 
• Start the discharge procedure using Arduino. 
Charging: 
• Before charging the cell, connect the power 
supply to cell tabs one wire at a time. 
• Connect positive wire to positive terminal of 
the cell and negative wire to negative terminal 
of the cell. 
• Set the power supply parameters to the 
manufacturer provided full charged value. 
• Turn on the power supply. 
Warnings 
• Do not touch the cell terminals while a 
discharge/charge procedure is under way. 
• Never try to disassemble a cell. 
4.3 Shut Down 
Turn off the power from the Power Supply/Load bank 
and verify using the Arduino that the system has no 
current running through it, disconnect the connector 
and then unclamp and disconnect the wires from the 
cell tabs one at a time. All cell testing equipment must 
be disassembled and locked into storage. 
 
5. MAINTENANCE 
5.1 Operator 
During testing, cell(s) must be monitored using a BMS 
system or individual sensors. Usage must be stopped if 
the environmental conditions are too extreme (See 
manufacturer’s specifications). 
5.2 Maintenance/Manufacturer 
 
N/A 
 
6. TROUBLESHOOTING 
• A ‘hot cell’ or a ‘vented cell’ must be isolated & 
tagged out immediately if safe to do so, 
otherwise personnel must be evacuated from 
the area until the cell has cooled down again. 
Refer to Hot Cell SOP # 1.3. 
 
7. EMERGENCY 
• Shut down the equipment with the emergency 
stop. 
• PPE required after emergency stop until fault 
has been found. 
 
In case of significant injury or damage: 
• Contact emergency services on 000 then notify 
University security on 8344 6666. 
 
8. REFERENCES 
 
8.1 Legislation 
• Occupational Health and Safety Act 2004 (Vic) 
• Occupational Health and Safety Regulations 
2017 (Vic) 
 
8.2 Standards 
• IEC 62133 Battery Safety Testing 
• UL 1642 – Standard for Lithium Batteries (Cells) 
 
8.3 Codes and Guidance 
• Code of practice for risk assessment 2011 
• Code of practice for OHS consultation 2011 
• Risk management at work 2011. 
• Electrochem Solutions - Primary Lithium Battery 
Safety and Handling Guidelines 
 
8.4 University Procedures/Guidance 
• Standard Operating Procedures for Electrical 
Appliances 
• Electrical Inspection and Testing Procedure 
• Hot cell SOP # 1.3 
Accumulator
Page 33
safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 1 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
 
Figure 1: Power Supply to charge the cell 
 
1. INTRODUCTION 
 
This Standard Operating Procedure documents 
Melbourne University Racing Accumulator team’s 
approach to the safe operation of charging a single cell. 
Each of the fully charged cells will later be used for cell 
testing. 
 
2. REQUIREMENTS 
2.1 Training/Licensing 
Personnel shall have the following certifications: 
• MUR Hazardous Voltage and Safe Work Training 
2.2 Personal Protective Equipment 
N/A 
2.3 Other 
● Insulated cable shears, screwdrivers and other 
tools 
● Multimeter with protected probe tips 
 
 
 
3. WARNINGS/SPECIAL REQUIREMENTS 
There are several risks associated with improper 
operation while charging a single cell. These risks can 
include: 
• fire 
• fumes from damaged cell 
• Creation of hot cell (See Hot Cell SOP # 1.3) 
 
4. OPERATION 
 
4.1 Start Up 
• Workspace must be inspected before starting 
single cell charging. Ensure there are no metal 
objects lying nearby on the bench. 
• Remove any jewellery, such as rings, to prevent 
short-circuiting the cell. 
• Work surfaces must be non-conductive and 
clean from debris. 
• Cells must remainin their original packaging 
until they are put into the charging jig. 
• A battery management system (BMS) must be 
installed to ensure a safe and proper 
monitoring of the cell charge level and BMS 
must be tested prior to commencing work. 
• When setting up power supply output, do not 
exceed the manufacturer specified current and 
voltage ratings. 
• When placing sensors, ensure you avoid short 
circuiting the cell with the sensor. 
• Double-check the setup procedure before 
powering up the power supply. 
• If cell charging is to take place unattended, then 
a “cell charging in progress” sign should be 
shown with the contact details of the person 
charging. The person MUST be on call. 
4.2 During Operation 
• Connect the cables from the cell jig to the BMS 
device on one port. 
• Connect the power supply to the positive and 
negative terminal of the BMS device at another 
port. 
• Power up the BMS device. 
• Check charge indicator LED status. 
• Power up the charging power supply. 
 
 
[Division/Department] 
STANDARD OPERATING PROCEDURE 
[Charging a single cell] 
SOP No. 1.2 
 
Date: August 2017 
Review Date: April 2018 
Version No. 1.0 
Authorised by: Dragan Nesic 
 
Accumulator
4.5.2 Cell Charging
After a discharge/testing event, a cell must be charged again, and it is important to know what the as-
sociated risks are, what the best practise would be and how to be safe when making connections to the
cell. Accumulator sub-team felt that it was important to have a detailed procedure available so that no one
trying to engage in the process of cell charging falls short of safety standards of the MUR-Electric team.
Page 34
safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 2 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
4.2 Shut Down 
• When the cell is fully charged, the relay will 
open, thus the power supply will be 
disconnected from the cell and the full charge 
LED indicator will turn on. 
• Turn off the 12V cell charging power supply. 
• Turn off the BMS power supply and disconnect 
the cable. 
• Disconnect the cable from BMS to the Cell Jig. 
• Remove the cell from the jig. 
• Place the cell in a safe container. 
 
 
5. MAINTENANCE 
5.1 Operator 
During charging, the cell must be monitored using a 
BMS system. Connections must not be loose and 
everything must be connected properly before 
charging/discharging the cell. Cell charging must be 
stopped if the BMS signals a fault or if the 
environmental conditions are extreme to prevent 
damaging the cells. 
5.2 Maintenance/Manufacturer 
 
N/A 
 
6. TROUBLE SHOOTING 
 
• In case of a ‘hot cell’ or a ‘vented cell’ refer to 
the Hot Cell SOP (SOP #1.3). 
 
7. EMERGENCY 
 
• Shut down the equipment with the emergency 
stop. 
• PPE required after emergency stop until fault 
has been found. 
 
In case of significant injury or damage: 
• Contact emergency services on 000 then notify 
University security on 8344 6666. 
 
8. REFERENCES 
 
8.1 Legislation 
 
• Occupational Health and Safety Act 2004 (Vic) 
• Occupational Health and Safety Regulations 
2017 (Vic) 
 
8.2 Standards 
 
• UL 1642 – Standard for Lithium Batteries (Cells) 
 
8.3 Codes and Guidance 
 
• Code of practice for risk assessment 2011 
• Code of practice for OHS consultation 2011 
• Risk management at work 2011. 
 
8.4 University Procedures/Guidance 
 
• Standard Operating Procedures for Electrical 
Appliances 
• Electrical Inspection and Testing Procedure 
• Isolation lock out and tag out requirements 
 
 
 
 
 
 
 
 
Accumulator
Page 35
safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 1 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
 
Figure 1: Module/Segment used in an Accumulator 
 
Figure 2: Top of the Module with Cu, Al and HDPE blocks 
1. INTRODUCTION 
 
This Standard Operating Procedure documents 
Melbourne University Racing Accumulator team’s 
approach to the safe management of Accumulator 
during construction, maintenance and testing. 
MUR is building an electric car for the FSAE 
competition. Accumulator is a high voltage battery that 
is basically fuel for the electric car. Making an 
Accumulator involves packaging individual cells into 
modules or segments and then connecting these 
modules in an accumulator container to make a high 
voltage battery. 
 
2. REQUIREMENTS 
2.1 Training/Licensing 
 
Personnel shall have the following certifications: 
● MUR Hazardous Voltage and Safe Work 
Training 
2.2 Personal Protective Equipment 
 
These are the PPE items that are required to work 
safely with High Voltages: 
• Face shield/Hard hat 
• HV insulating gloves 
• Safety glasses with side shields 
• Toe capped boots (steel caps not required) 
2.3 Other 
• Insulated cable shears, screw drivers and other 
tools 
• Multimeter with protected probe tips 
• Rubber foot mats 
• Insulation blankets 
• Buddy system 
 
 
3. WARNINGS/SPECIAL REQUIREMENTS 
 
There are several risks associated with High Voltage. 
These risks can include: 
• electric shock from direct or indirect contact; 
• arcing or explosion; and 
• fire. 
 
The outcome of these risks can include: 
• burns associated with direct contact; 
• burns associated with equipment/infrastructure fire; 
• permanent muscular damage; 
• death; 
• nausea and vomiting; 
• palpitations and heart arrhythmias; 
• unconsciousness; and 
• inhalation of toxic gases. 
 
 
 
 
 
[Melbourne University Racing] 
STANDARD OPERATING PROCEDURE 
[Segment/Accumulator Assembly and Testing] 
SOP No. 2.1 
 
Date: 22 August 2017 
Review Date: April 2018 
Version No. 1.0 
Authorised by: Dragan Nesic 
 
Accumulator
4.5.3 Module/Accumulator Assembly & Testing
The design of the module/segment is quite specific and requires special instructions as it is not something
that is found everywhere. The design changes for a particular type of cell selected and a procedure must be
put in place to ensure that current/future accumulator sub-teammembers follow the correct procedures as
now it ismore thanone cell and that despite being considered lowvoltage, poses a significant risk to thehealth
and safety ofpersonnel.
Page 36
safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 2 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
4. OPERATION 
4.1 Start Up 
1. Workspace must be inspected daily before 
starting work on High Voltage Equipment to 
make sure that there are no electrical safety 
hazards. Equipment must also be inspected and 
any damaged equipment must be isolated. 
2. Written work and training instructions must be 
available for each manufacturing procedure. 
3. Work surfaces must be non-conductive. 
4. All jewellery must be removed to prevent short 
circuiting the battery. 
5. Appropriate personal protective equipment 
must be worn (See PPE section above). 
6. Cells must remain in their original packaging 
until they are placed into the battery pack. 
7. Modules must be transported in trays or on 
pushcarts to reduce the probability of dropping 
and to reduce manual handing hazards. 
8. When loading cells and packs during electrical 
tests, use caution not to exceed the current 
rating of the fusing. 
9. Series fuses must be fitted external to the 
battery to allow for replacement. 
10. Each individual cell must be fused at the 
terminals for the appropriate current rating. 
4.2.1 During Operation 
1. The heat output of a pack during operation 
must be evaluated to ensure a safe operating 
temperature is maintained. 
2. All cells and batteries must be protected against 
excessive shock and vibration. 
3. Use of a battery management systemto 
monitor against charge and discharge, 
operating temperature to ensure cell is 
operated within manufacturers specifications. 
This prevents abuse of the battery pack and 
extends battery life. 
4. Wires must be trimmed one at a time and off 
cuts collected to prevent them falling into the 
module and creating short circuits. 
5. All packs must be labelled with High Voltage 
warning 
4.2.2 Assembling a Segment 
1. Always use 1000V rated insulated tools when 
working on segments. 
2. Drill two holes through the cell tabs for all the 
cells. 
3. Get a plate with slots for cell tabs. 
4. Push the first cell through the plate so the tabs 
are sticking out on the other side. 
5. Cover the tabs of the cell to avoid short circuits. 
6. Use a segment plate on the outer side with two 
holes on each side. 
7. Insert the neoprene sheet. 
8. Insert another cell in an equivalent manner to 
steps 3 and 4. 
9. Use a segment plate on the inner side with two 
holes on each side. 
10. Repeat process until the required number of 
cells in a segment are reached. 
11. Add two endplates to the segment with 
mounting holes for the accumulator container 
and holes on the side to apply constant 
pressure across the surface area of the cells. 
12. Push screws through the side holes of the 
endplates and the segment plates and tighten 
everything. 
13. Next, take polyethylene and Aluminium blocks 
alternately and align them with the holes on the 
tabs. Use copper blocks for the positive and 
negative terminal of the segment. 
14. Arrange them so that the whole segment has 
cells connected in series, now push through 
long bars through the holes and tighten 
properly. 
15. Attach the upper plate to the segment along 
with the connectors. 
4.2.3 Assembling the Accumulator 
1. Connect the segments together in such a way 
that all the segments connect in series. 
2. Pay attention to the polarities when connecting 
the segments together. 
3. Bolt the segments to the Accumulator 
containers. 
4. Connect the three containers together using 
connectors and wires. 
4.3 Shut Down 
All High Voltage Equipment must be disassembled and 
locked into storage. 
 
5. MAINTENANCE 
5.1 Operator 
Accumulator must be charged/discharged within 
manufacturer specified current and voltage maximums. 
Battery Management System must be used to monitor 
the individual cells as well as the whole battery pack. 
Usage must be stopped if the environmental conditions 
are outside manufacturer stated operating range or 
BMS signals that cell(s) are not operating in their safe 
range. 
 
5.2 Maintenance/Manufacturer 
N/A 
 
6. TROUBLESHOOTING 
 
Accumulator
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safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 3 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
• A ‘hot cell’ or a ‘vented cell’ must be dealt with 
according to ‘Hot cell handling SOP’ (SOP 1.3). 
• A Electric Safety Officer must always be present 
while students are working on High Voltage. 
 
7. EMERGENCY 
 
● Shut down the equipment with the Emergency 
stop 
● PPE required after emergency stop until fault 
has been found 
 
In case of significant injury or damage: 
● Contact emergency services on 000 then notify 
University security on 8344 6666 
 
8. REFERENCES 
 
8.1 Legislation 
• Occupational Health and Safety Act 2004 (Vic) 
• Occupational Health and Safety Regulations 
2017 (Vic) 
 
8.2 Standards 
• IEC 62133 Battery Safety Testing 
• UL 2054 – Standard for Household and 
Commercial Batteries 
• UL 1642 – Standard for Lithium Batteries (Cells) 
• SAE J 1797 Recommended Practice for 
Packaging of Electric Vehicle Battery Modules 
• SAE J 2344 Guidelines for Electric Vehicle Safety 
 
8.3 Codes and Guidance 
• Code of practice for risk assessment 2011 
• Code of practice for OHS consultation 2011 
• Risk management at work 2011. 
• Gloves – AS/NZS 2161.2: Occupational 
protective gloves: general requirements 
• Respiratory protection – AS/NZS 1715: 
Selection, use and maintenance of respiratory 
protective equipment 
• Electrochem Solutions - Primary Lithium Battery 
Safety and Handling Guidelines 
 
8.4 University Procedures/Guidance 
• Electrical Equipments in Hostile Environments 
• Standard Operating Procedures for Electrical 
Appliances 
• Electrical Inspection and Testing Procedure 
• Isolation, Lock out and Tag out Requirements 
Accumulator
Page 38
safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 1 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
 
Figure 1: Module/Segment used in an Accumulator 
 
Figure 2: Top of the Module with Cu, Al and HDPE blocks 
1. INTRODUCTION 
 
This Standard Operating Procedure documents 
Melbourne University Racing Accumulator team’s 
approach to the safely swapping out a damaged cell. 
Accumulator is a high voltage battery that acts like a 
fuel tank for the electric car. Making an Accumulator 
involves cell testing, packaging individual cells into 
modules or segments and then connecting these 
modules in an accumulator container to make a high 
voltage battery. 
 
2. REQUIREMENTS 
2.1 Training/Licensing 
 
Personnel shall have the following certifications: 
● MUR Hazardous Voltage and Safe Work 
Training 
2.2 Personal Protective Equipment 
 
These are the PPE items that are required to work 
safely with High Voltages: 
• Face shield/Hard hat 
• HV insulating gloves 
• Safety glasses with side shields 
• Toe capped boots (steel caps not required) 
2.3 Other 
• Insulated cable shears, screw drivers and other 
tools 
• Multimeter with protected probe tips 
• Rubber foot mats 
• Insulation blankets 
• Buddy system 
 
3. WARNINGS/SPECIAL REQUIREMENTS 
 
There are several risks associated with High Voltage. 
These risks can include: 
• electric shock from direct or indirect contact; 
• arcing or explosion; 
• fire and 
• Chemical hazards 
 
The outcome of these risks can include: 
• burns associated with direct contact; 
• burns associated with equipment/infrastructure 
fire; 
• permanent muscular damage and/or death; 
• death; 
• nausea and vomiting; 
• palpitations and heart arrhythmias; 
• unconsciousness; and 
• inhalation of toxic gases. 
 
4. OPERATION 
4.1 Start Up 
 
[Melbourne University Racing] 
STANDARD OPERATING PROCEDURE 
[Swapping out a damaged cell from the 
Segment/Accumulator] 
SOP No. 2.2 
 
Date: 22 August 2017 
Review Date: April 2018 
Version No. 1.0 
Authorised by: Dragan Nesic 
 
Accumulator
4.5.4 Swapping Damaged Cells
This is not something that would often have to be done. This is because each cell that goes in a segment is
already tested tohavebeenworkingwell andonly in the rare case that something goeswrong andone cellmal-
functions, would this be required. Because of the extremely low chance of this happening, a proceduremust
be put in place to ensure safety of personnel as remembering the exact steps of a procedure that only has to be
doneonce in abluemoon is an impossible task.
Page 39
safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 2 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
1. Workspace must be inspected daily before 
starting work on High Voltage Equipment to 
make sure that there are no electrical safety 
hazards. Equipment must also be inspected and 
any damaged equipment must be isolated. 
2. Written work and training instructions must be 
available for each manufacturing procedure. 
3. Work surfaces must be non-conductive. 
4. All jewellery must be removed to prevent short 
circuiting the battery. 
5. Appropriate personal protective equipment 
must be worn. 
6. Cells must remain in theiroriginal packaging 
until they are placed into the battery pack. 
7. Series fuses must be fitted external to the 
battery to allow for replacement. 
8. Each individual cell may be fused at the 
terminals for the appropriate current rating. 
4.2 During Operation 
1. Identify the segment with the damaged cell 
using the data available. 
2. Remove the segment from the Accumulator 
container. 
3. Remove the terminal connectors and separate 
the top plate of the segment. 
4. Remove the bars going through the Al, HDPE 
and Cu tabs. 
5. Remove all the tabs. 
6. Remove the side screws from both the end 
plates and the segment plates. 
7. Identify the cell to be removed. 
8. Isolate the cell carefully by removing the 
surrounding cells on one side. 
9. Drill two holes through the cell tabs for the new 
cell. 
10. Swap out the cell and follow Hot Cell SOP 
(SOP 1.3). 
11. Repack all the cells again by following the 
accumulator assembly SOP (SOP 2.1). 
4.3 Shut Down 
All High Voltage Equipment must be disassembled and 
locked into storage. 
 
5. MAINTENANCE 
5.1 Operator 
Accumulator must be charged/discharged at the 
manufacturer specified current and voltage. Battery 
Management System must be used to monitor the 
individual cells as well as the whole battery pack. Usage 
must be stopped if the environmental conditions are 
too extreme or BMS signals that cell(s) are not 
operating in their safe range. 
 
5.2 Maintenance/Manufacturer 
N/A 
 
6. TROUBLESHOOTING 
 
• For ‘Hot’ or vented cells refer to ‘Hot Cell SOP‘ 
(SOP 1.3). 
• Electric Systems Officer must always be present 
while students are working on High Voltage. 
 
7. EMERGENCY 
 
● Shut down the equipment with the emergency 
stop 
● PPE required after emergency stop until fault 
has been found 
 
In case of significant injury or damage: 
● Contact emergency services on 000 then notify 
University security on 8344 6666 
 
8. REFERENCES 
 
8.1 Legislation 
• Occupational Health and Safety Act 2004 (Vic) 
• Occupational Health and Safety Regulations 
2017 (Vic) 
 
8.2 Standards 
• UL 2054 – Standard for Household and 
Commercial Batteries 
• UL 1642 – Standard for Lithium Batteries (Cells) 
• SAE J 1797 Recommended Practice for 
Packaging of Electric Vehicle Battery Modules 
• SAE J 2344 Guidelines for Electric Vehicle Safety 
 
8.3 Codes and Guidance 
• Code of practice for risk assessment 2011 
• Code of practice for OHS consultation 2011 
• Risk management at work 2011. 
• Gloves – AS/NZS 2161.2: Occupational 
protective gloves: general requirements 
• Respiratory protection – AS/NZS 1715: 
Selection, use and maintenance of respiratory 
protective equipment 
• Electrochem Solutions - Primary Lithium Battery 
Safety and Handling Guidelines 
 
8.4 University Procedures/Guidance 
• Electrical Equipments in Hostile Environments 
• Standard Operating Procedures for Electrical 
Appliances 
• Electrical Inspection and Testing Procedure 
• Isolation, Lock out and Tag out Requirements 
Accumulator
Page 40
safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 1 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
 
Figure 1: Accumulator Container 
 
1. INTRODUCTION 
 
This Standard Operating Procedure documents 
Melbourne University Racing Accumulator team’s 
approach to the safe management of removing an 
accumulator pack from the FSAE car. 
We are using two/three accumulator packs with weight 
of approx. 45kg each. This involves charging the whole 
battery pack at up to 350V which falls within the FSAE 
defined High Voltage range. 
 
2. REQUIREMENTS 
2.1 Training/Licensing 
 
Personnel shall have the following certifications: 
● MUR Hazardous Voltage and Safe Work 
Training 
2.2 Personal Protective Equipment 
 
These are the PPE items that are required to work 
safely with High Voltages: 
• Face shield/Hard hat 
• HV insulating gloves 
• Safety glasses with side shields 
• Toe capped boots (steel caps not required) 
2.3 Other 
• Insulated cable shears, screw drivers and other 
tools 
• Multimeter with protected probe tips 
• Rubber foot mats 
• Insulation blankets 
• Buddy system 
 
3. WARNINGS/SPECIAL REQUIREMENTS 
 
There are several risks associated with removing an 
accumulator pack. These risks can include: 
• Injury to personnel because of incorrect lifting 
methods. 
• Electric Shock Hazards because the tractive 
system is not switched off. 
 
4. OPERATION 
4.1 Start Up 
• All jewellery MUST be removed to prevent 
short circuiting the battery. 
• Appropriate personal protective equipment 
must be worn (See PPE section above). 
• A charge cart MUST be present where one can 
place the accumulator containers after 
removing them from the car. 
• Make sure the car is not moving and the driver 
is safely out of the vehicle. 
• The Tractive system and low voltage system 
switches must be off and locked. 
• Disconnect one Accumulator container at a 
time and one wire at a time. 
• Remove all the screws to release the 
accumulator container from the chassis 
ensuring that the lose container does not 
damage the chassis (causing a potential weak 
point in the structure of the car) or cause injury 
to the personnel handling the container 
because of the unscrewed container’s 
unexpected movement. 
• Two personnel should move each container 
forward and slowly lift it up using the correct 
posture. Refer to Manual Handling training 
module for details. 
• Place the container on the charge cart ensuring 
that the container is fully on the charge cart and 
not unbalanced or hanging off the edge. 
• Repeat for each container. 
4.2 During Operation 
 
[Melbourne University Racing] 
STANDARD OPERATING PROCEDURE 
[Charging the Accumulator Pack] 
SOP No. 2.3 
 
Date: 22 August 2017 
Review Date: April 2017 
Version No. 1.0 
Authorised by: Dragan Nesic 
 
Accumulator
4.5.5 Accumulator Removal and Charging
There is a significant risk of untrained personnel damaging their back while removing the accumulator pack
from the car. So, a correct proceduremust be inplace so that allmembers are aware of the risk. A lot of people
take simple things for granted but if not done with the correct posture, lifting a heavy battery container can
cause a long-term injury. On topof this, there are electrical risks involvedwith thebattery container thatmust
beminimized.
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safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 2 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
• Connect the accumulator containers to form 
one pack. 
• Connect the charger to the positive and 
negative terminal of the accumulator pack. 
• Turn on the charger. 
4.3 Shut Down 
• Turn off the charger 
• Disconnect the charger from the pack. 
• Disconnect the accumulator packs. 
• Lift one container at a time and place back into 
the car. 
• Secure it on to the chassis and make sure that 
all points have been screwed on. 
• Repeat for all containers. 
• Connect all the containers together to complete 
the battery. 
 
MAINTENANCE 
5.1 Operator 
During charging, cell(s) must be monitored using a BMS 
system or individual sensors. Connections must not be 
loose and must be connected properly before 
charging/discharging the cell. Usage must be stopped if 
the BMS signals a fault or if the environmental 
conditions are outside manufacturer’s recommended 
range. 
 
5.2 Maintenance/Manufacturer 
N/A 
 
5. TROUBLESHOOTING 
 
• In case of damaged or ‘vented cell’ refer to Hot 
Cell SOP (SOP # 1.3). 
• Damaged cells must be isolated, marked and 
recycled according to the university policy (SOP 
# 1.3). 
 
6. EMERGENCY 
 
• Shut down the equipment with the emergency 
stop. 
• PPE required after emergency stop until fault 
has been found.In case of significant injury or damage: 
• Contact emergency services on 000 then notify 
University security on 8344 6666. 
 
7. REFERENCES 
7.1 Legislation 
• Occupational Health and Safety Act 2004 (Vic) 
• Occupational Health and Safety Regulations 
2017 (Vic) 
 
7.2 Standards 
• UL 1642 – Standard for Lithium Batteries (Cells) 
 
7.3 Codes and Guidance 
• Code of practice for risk assessment 2011 
• Code of practice for OHS consultation 2011 
• Risk management at work 2011. 
• Gloves – AS/NZS 2161.2: Occupational 
protective gloves: general requirements 
 
7.4 University Procedures/Guidance 
• Standard Operating Procedures for Electrical 
Appliances 
• Electrical Inspection and Testing Procedure 
• Office Ergonomics and Manual Handling 
Accumulator
Page 42
safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 1 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
 
 
[Melbourne University Racing] 
STANDARD OPERATING PROCEDURE 
 [Low Voltage (LV) Crimping] 
 
SOP No. 4.3 
 
Date: Aug 2017 
Review Date: April 2018 
Version No. 1.0 
Authorised by: Dragan Nesic 
 
 
 
Figure 1: Ratchet Crimping Tool 
 
 
Figure 2: Different wire sizes have different slots for crimping 
 
Figure 3: Weidmüller Cable Stripping Tool 
 
1. INTRODUCTION 
This SOP will outline how to correctly attach lugs and 
connectors to FSAE low voltage wiring (LV). 
 
2. REQUIREMENTS 
2.1 Training/Licensing 
Personnel shall have the following certifications: 
● MUR Hazardous Voltage and Safe Work 
Training (if using for voltages above 60VDC) 
2.2 Personal Protective Equipment 
No PPE is required to perform this task. 
2.3 Other 
- Clear workspace (never in vehicle) 
- Wire 
- Heat shrink tubing + heat gun 
- Wire cutting tools & file 
 
3. WARNINGS/SPECIAL REQUIREMENTS 
 
• Operators should always familiarise themselves 
of where the emergency release is located for 
each specific tool. 
• Caution must be taken to avoid injury from 
pinching fingers/hands within the crimping tool. 
• Ensure off cuts do not fall anywhere that can 
cause short circuits. 
 
4. OPERATION 
4.1 Start Up 
• Cut a length of cable for the desired wiring run, 
ensure that the end of the cable is flat. 
• Preparing the cable for crimping by first 
removing the outer layer of insulation by using 
a cable stripping tool (eg Weidmüller as shown 
in Figure 3). 
4.2 During Operation 
• Push the lug onto the cable, ensure all the 
strands in the wire are pushed into the lug. 
Accumulator
4.5.6 Low Voltage Wire Crimping
To make connections that are long lasting and secure, crimping must be done. This is because during oper-
ation an electric race car experiences high forces and strong connections are essential. Not many people are
experiencedwith this procedure, whichwas the case for the accumulator sub-teamof 2017. Hencewhy, itwas
important todevelop this document.
Page 43
safety.unimelb.edu.au STANDARD OPERATING PROCEDURE 2 
Date: September 2015 Version: 1.1 Authorised by: Associate Director, Health & Safety Review Date: September 2018 
© The University of Melbourne – Uncontrolled when printed. 
Stray strands MUST not be trimmed off if they 
don’t end up in the lug. Remove lug, give 
strands a light twist to bring them together 
then replace the lug onto the cable so that 
there are no stray strands. 
• Select the cable or lug size on the crimping tool, 
if relevant adjust the angle of the lug before 
crimping. 
• Align the crimping tool on the lug, cable should 
be on the left of the crimping tool and apply 
some force to the crimper’s arms. 
• Ensure your fingers are not in the tool before 
applying full pressure to the crimper’s arms. 
 
4.3 Shut Down 
Sweep up and dispose of all metal scraps and insulation 
material. 
 
5. MAINTENANCE 
5.1 Operator 
Check tools are operating correctly before use. 
5.2 Maintenance/Manufacturer 
Check tools for damage. 
 
6. TROUBLE SHOOTING 
If all the strands don’t fit in the lug, double check the 
lug size against the cable. 
 
7. EMERGENCY 
In case of significant injury or damage: 
• Contact emergency services on 000 then notify 
University security on 8344 6666. 
 
8. REFERENCES 
8.1 Legislation 
• Occupational Health and Safety Act 2004 (Vic) 
• Occupational Health and Safety Regulations 
2017 (Vic) 
 
8.2 Standards 
• Solderless crimped connections AS/NZS 
4437:1996 
 
8.3 Codes and Guidance 
• Code of practice for risk assessment 2011 
• Code of practice for OHS consultation 2011 
• Risk management at work 2011. 
 
8.4 University Procedures/Guidance 
• Office Ergonomics and Manual Handling 
 
Accumulator
Page 44
Accumulator
5 Design Development
This section of the report discusses the design decisions for different components that are part of the tractive
system and are the responsibility of the accumulator team. It also discusses how the design of some compo-
nents such as the accumulator container and the segment had to be changed as some other sub-teams made
changes to the car design. The basic design constraints are given below.
5.1 Design Constraints
A lot of the design decisions were affected and made because of the FSAE rules requirements. As the rules
that apply to the accumulator team are too long to be listed only some will be mentioned in the relevant
sections of the report. The rest can be found on the FSAE website [2]. The design requirements in order of
importance are:
• Make the safest possible system and at the very least comply with the safety regulations laid out in the
FSAE rules.
• Supply the maximum allowable power (80kW) at the desired voltage to the motors.
• Store enough energy to power the car for the entire endurance event.
• Keep the accumulator pack light weight.
• Quick dis-assembly of the pack if there is a need for replacing any of the cells.
The first design discussion is about cell segmentation. This is the most vital component in the battery pack
as the battery is made up of these segments connected in series.
5.2 Cell Segmentation
Toprovide a large amountof energy tobeused as a racing car’s powerhouse, battery cells need tobe assembled
together. A single battery cell can provide a current as high as 200A continuous and 600A pulse. However,
a single cell is only capable of providing a nominal voltage level of 3.3V. Therefore, to solve this problem,
the cells are combined in series arrangement as such arrangement will increase the overall voltage without
altering the current taken from the battery cells.
Power delivery can be increased by increasing the overall current as well. However, an extremely high
current design is unfavourable for many reasons. First reason being that the system tends to become more
dangerous withmore current being present and drawn from the battery. In fact, 200A is already a great level
of current. Higher current will increase the heat dissipated from the battery and potentially damage the cell.
Even though the cell is capable of discharging 600A current in pulse, it is best to be avoided. In addition, the
motor used can only take up amaximumcurrent of 200A for 2minuteswhenproperly cooled.[38] Secondly,
components sourcing becomemore problematic and cost inefficient sincemost Electric Vehicle components
are rated at 600-1000Vwhile the current rating varies from 50A to 350Awith each higher current level being
significantly more expensive.
5.2.1 Initial Design
There were numerous iterations of the segments with improvement on every updated version of the design.
Initially, themain objective was to provide the required power regardless of the shape and design as a starting
point. However, during the primary design phase, there was no proper information that could be referenced
on to decide howmuch voltage should be set for the whole accumulator system.
It was firstly decided to follow the maximum voltage that the motor can take in.It turns out however,
that the price of the battery would be too expensive, and the size of the entire systemwould be too large to fit
Page 45
Accumulator
inside the car chassis. This is because the motor used is a high voltage motor with maximum battery voltage
of 470V DC[38]. (Refer to Appendix A.1.4)
Therefore, a more thorough research was made and visits to other teams were made to get suggestion
and recommendation based on their experience. As a result, using resources from the integration team,
simulation of the race was conducted with worst case power scenario of endurance event. Endurance event
in FSAE is one part of the race in which the car must run for distance if approximately 20km nonstop[2].
This is where most energy will be required and therefore should be set as the main constraint. Hence, it
was found that 88 cells were the minimum amount of battery cells required to provide enough power with
the current configuration at the time. However, to divide the segments equally, 96 cells were set as the final
number as it can be divided into 8 segments with 12 cells installed per segment. 2017 FSAE rules require
the segment to be separated inside one or few containers. Each segment placement cannot exceed a weight
of 12kg, voltage of 120V DC and total energy of 6MJ[2]. Installing 12 cells per segment matched the rule
requirement while makes it still easy to assemble and test individually.
5.2.2 Cooling Plate/Fins
As per experience and result from other FSAE teams and as recommended from the data sheet [24], the cells
require cooling plates to be placed on the surface of the battery to dissipate heat produced effectively when
power is drawn away from the battery. As a result, new segment was designed with cooling plates in mind.
The cooling plates were designed thick enough to be able to dissipate heat easily and the bottom part of
the plates were designed as a block to provide structure to the battery cell segment. Thus, the main purpose
of the segment fins was to provide both structure and passive cooling system to the cells.
Figure 14: Full Segment with 30 Cells (left) and First Cooling Plate Design (right)
The picture shown in Figure 14 is the first full segment configuration (left)with thick segment separation
installed. The individual cooling plates/separationon canbe seen the right. The thick sides andbottomparts
of the fins was designed based on the principal that the thicker the aluminium plate is, the more heat that it
can absorb from the battery cell. The end plate on the edge of the segment was designed in certain way so
that someweight could be reducedwhile still providing a rigid structural integrity for thewhole accumulator
segment.
At this stage, manufacturability was not considered much in the design aspect as the overall purpose on
the initial design is to provide an estimate size and placement of the segment.
Page 46
Accumulator
Figure 15: Trimmed down segment plate
Theoretically, the designwouldwork just fine with sturdy structure and sufficient cooling of the battery.
However, it was deemed to be too heavy and unnecessary to have thick block at the bottom of each plate.
Therefore, to reduce weight significantly without losing the cooling properties, the segment fins bottom
thickness was reduced to 5mm thick compared to 20mm previously. This can be seen in Figure (14) and (15).
Moreover, manufacturability started to be taken into consideration in the design. After consulting with
Randy fromHolmesglen Institute of TAFE, lots ofmaterials would be wasted if the fins weremade this way
and done through CNCmachining. Therefore, after several discussions from different departments, it was
deemed that laser cuttingwould bemore compatible with the design. Small thin aluminiumplates would be
stacked together to make one segment fin. However, this was still not the optimal solution in approaching
the fin design.
Figure 16: Newly designed aluminium fins/structure with bent aluminiummaterial
Due to difficulty in manufacturing, the previous fin design was improved once again. It was also found
that the laser cutting outsource can provide accurate bends with heavy machinery. Therefore, new design
as shown in Figure 16 was made. The holes were made to help aligning the accumulator segment structure
during assembly. By having a metal bar through each hole, it will get both the cells and the structure always
at the same level. Therefore, the pressure applied will also be equal on every cell within the segment. The
bars will then be bolted at the end of the segment to a steel plate, referred as end plate.
In terms of thermal cooling, it was found based on the property of aluminium and the potential heat
generation from the battery cells, aluminium with a thickness of 1mm is sufficient to cool down the cells
Page 47
Accumulator
adequately. This was approached positively as it could reduce the mass of the whole accumulator system by
several kilograms.
Figure 17: Segment assembled with 3d Printed Top plate
The end plates are responsible in applying the pressure and securing the whole segment structure to the
accumulator container. The container will be able to withstand a force of 40g as required by the FSAE rule.
In terms of material, all the design was configured to be made with aluminium (Thermal conductivity
= 205 W/m K) [39]. Theoretically, copper provides a better thermal conductivity (385 W/m K), however,
the material does not seem to fit well with the purpose of the race car accumulator for many reasons. Firstly,
copper tends to corrode overtime compared to aluminium. Although the system will be enclosed in a con-
tainer, environmental damage might still occur which can potentially damage the battery cells or the entire
system. Secondly, copper has a density of 8.96 g/cm3 while aluminium has a density of only 2.70 g/cm3.
This means that for an identical sized object, copper will be 3.3 times heavier than aluminium whilst only
providing less than 2 times better thermal conductivity. A more thorough thermal analysis can be found
later in the document.
A suggested idea to use small pieces of copper was also considered on the design. However, it was re-
quired for the pressure to be spread evenly throughout the battery for it to perform and last well. Addition-
ally, copper will still corrode overtime regardless of the size, thus, such method could not be implemented.
5.2.3 Cell Interconnection
Figure 18: 3D Printed top plate (left) and wedges (right) Note: Image not on proper scale
Page 48
Accumulator
Figure 18 shows the 3D printed component of the segment. The main idea of the interconnection was to
put the battery cell tabs in between the holes and then wedged by the aluminium. The wedges will then be
held tightly by a bar on top of the plate.
Thewedges were planned to bemade by usingAluminium grade 6061 and copper for the terminal ends.
This is to ensure effective electrical connection to the BMS through the aluminium and terminal connec-
tion through the copper that can withstand the rate of 200A. The reason for choosing aluminium is due
to its lighter and cost-effective properties. The tabs connection inside the segment will be touching directly.
Therefore, in theory, an insulator will suffice as the wedges. However, connection from each battery cell
to the BMS is required and conductive material is needed. Therefore, aluminium was chosen as it provides
sufficient current flow required by the BMS.
As per copper component, the material copper was chosen as they will act directly as the terminal of
each segment and high current (200A) will flow through the two ends. Copper has much higher electrical
conductivity (58.5× 106Siemens/m)[39], nonetheless, the material is heavier and more expensive compared
to aluminium (thermal conductivity of 36.9 × 106Siemens/m). Although mentioned in previous section
that copper will corrode overtime, the amount of copper used for the terminal has minimum surface area
compared to the segment fins. In addition,the terminal can be replaced easier without disassembling the
whole segment altogether. Regarding the top plate, the material used to print the prototype was PLA as it
was the only available material by the Melbourne School of Engineering.
Based on the chemical properties, ABSwere deemed to bemuchmore reliable and canwithstand amuch
higher temperature. However, for initial fitting and design and because PLAwas the onlymaterial available,
it was used to print the structure. The final printed material seemed sturdy from the outside and it was
printed in a honeycomb structure. However, when the screw was tested on the material, the material ap-
peared to be extremely brittle and shattered immediately. In addition, it could not withstand the amount
of heat that will be dissipated from the battery cell. When poured with constant running water of approxi-
mately 60◦ Celsius, the structure started to deform which is a negative indication for the material.
Figure 19: Broken 3D Printed Plate after Testing
Due tomajor flawof thedesign and structure, thewhole interconnectionwas redesigned. A fewmaterials
were considered on the new design of the interconnection, they include Kevlar, carbon fiber and acrylic.
Kevlar was one of the best material to be used as it provides rigid structure while being insulative at the same
time. However, the price of Kevlar is extremely expensive and it has bad manufacturability. Mould had to
be created and it is not very workable once it is formed, reducing the margin of error. As for carbon fiber,
manufacturability is similar with Kevlar and although it has good thermal capability, the material tend to be
electrically conductive, which is unsuitable for the interconnection as short circuit can potentially happen.
Lastly, acrylic seemed to be the best candidate as it is an electrically insulative material that can withstand
heat much higher than the PLA material. Manufacturability is also easy for acrylic as it can be sourced and
laser cut in house in Melbourne University Workshop.
Thus, acrylic was used as the new material due to its electrically insulative property, thermal capability and
easy manufacturability through laser cutting.
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Accumulator
Figure 20: Fully redesigned interconnection design
Figure 20 shows the new interconnection segment design. In comparison to the previous design, this
new design is sturdier and saves a bit of weight. In addition, disconnecting the segment becamemuch easier
due to the implementation of surlok connector from Amphenol. The system can now be easily plugged by
the male and female connector as opposed to screwing and bolting the terminals with previous design.
The whole top part will also be enclosed by acrylic, a good electrical insulator, to prevent user or peo-
ple from accidentally touching the terminals. Some airflow will be able to pass through for cooling, but
they will not be big enough for fingers to penetrate through. Therefore, the new system is much more fool
proof compared to the previous 3D printed system. The only downside of this design is that puncturing
the tabs is required to assemble the cells together. After consulting with the High Voltage Safety Instructor
(Bryce), teammembers and other FSAE team, it was concluded that puncturing the tabs will not reduce the
performance nor damage the cell in any way. Therefore, the design went ahead to manufacturing.
Figure 21: Segment assembled with new segment interconnect and end plates
As it can be seen on the new segment, each individual fin is also shorter compared to the end walls.
This is to ensure that no accident short will occur as the fins are made from aluminium. The end walls,
however, still have the normal height to provide structure to the top plate of the segment. Regardless, all the
components in close approximation to the tabs will be covered by Kapton tape which is an industry grade
electrical insulation.
In addition, the whole segment now appears to be much larger than the previous design. This is due
to a major change in design of the whole car. The accumulator containers which were initially designed to
sit behind the driver seat are now located on each side of the car, covered by sidepods. Due to dimension
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restriction, the segmentwill nowbe rotated 90degrees as compared to standingup. As a result, the endplates
needed to be stronger and provide support on the side as it will be mounted differently while still required
to be able to withstand 40g of force. Thus, there are more bolting points to the accumulator container to
hold on the weight and force.
Figure 22: Final 2017 Accumulator Segment Components Assembly
5.2.4 Prototyping
Initially, prototypingwas going tobedone as a 6 cells segment as theproper segmentwas going tobedesigned
with up to 30 segments. However, since the actual segment eventually designed to be 12 cells, prototyping
will be done as one complete segment. This decision was chosen as it saved time in designing and testing
since the final prototype will become the real segment once the testing is completed. Refer more regarding
the prototype result on the implementation section of the report.
5.2.5 Cabling
The cables used to connect the accumulator segments are double insulated orange welding cable with a cross
section area of 50 mm2. Such cable can handle a current flow of up to 250A. The orange colour is consistent
with the FSAE requirement which stated that all high voltage system needs to be separated and use connec-
tion with the colour orange. The connectors that will be used alongside the cables are the surlok connectors
which can be easily crimped into the cable, providing a secure and insulated connection.
Figure 23: Connectors to be used on the accumulator segment
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5.2.6 Handling
Installing and testing the segment were done with full care and with proper equipment. The equipment
included insulating mat, rubber gloves and face shield etc. Full list can be found in the OH&S report. Any
handling was only done after the High Voltage training and with the help from a professional electrician.
5.3 Low Voltage Battery
Aspart of side project for the accumulator team, the lowvoltage sub-team requires aDCbattery packwith an
approximate voltage of 12V (±2V ) to be implemented into their system. As the accumulator battery pack is
made from high energy density 3.3V cells, a low voltage battery can bemade by connecting 4 cells together in
series. As the cell used is the samewith the accumulator pack, equivalent safetymeasures were implemented.
The battery pack will have safety circuitry such as the BMS and relay connected to the system.
Figure 24: Low Voltage Battery Segment
Although itwas designed to have the same structure and componentswith the segment, the LowVoltage
Battery had tobe redesigneddue to componentmanufacture delay and cancellation. Thenewdesign consists
of a full acrylic body and tabs separation. The body structure both separates the cells and align the series tab
connection. Refer to section (6.2.2) for the complete assembly and implementation of the Low Voltage
Battery.
5.4 Accumulator Isolation Relay
Accumulator Isolation Relays (AIRs) are installed to shut down the whole accumulator system in case of an
emergency event.
5.4.1 Contactor
The component chosen to be used to serve the purpose of andAccumulator IsolationRelay is theKILOVAC
EV200 Series Contactor as it can withstand a continuous current of 500A and DC Voltage of up to 900V.
These ratings exceed the requirement of the battery as it operates at maximum current of 200A and DC
Voltage of 316.8V. A minimum of two contactors will be placed inside each accumulator container to open
both positive and negative terminals of the circuitry inside the container. The contactors are powered by the
Low-Voltage battery andwill be placedwithin each accumulator container so that theywill still be functional
during charging.
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Within the container, the AIRs, will be enclosed in afireproof compartment to ensure functionality
even when the segments catch on fire. AIRs will shut down the circuit when the temperature of the cells
rises above 55 degrees Celsius and if the master shutdown button is pressed.
5.4.2 Cabling
The cables used to connect to AIRs will be identical to those used to connect the segments and containers.
This is to ensure the current rating is consistent and for the fact that AIRs will be the last point before
input/output of each container.
5.5 Tractive System Active Light
The system can get a reading of voltage point greater than60Vand then send the signal to lowvoltage system.
The high voltage and low voltage systems are separated by using an optocoupler to ensure that the high
voltage sidedoes not distort the lowvoltage system. This system is the samewith theone implemented for the
Accumulator Indicator Light (Refer to section 5.12). The main difference is that the Tractive System Active
Light will be shown on top of the car while the Accumulator Indicator Light is shown on the accumulator
container itself.
5.6 Container/Housing
As mentioned briefly previously, the initial design of the container was to be placed behind the driver seat.
Like the segment design, the container faced numerous iterations in order to improve the overall design
and to fit with the requirement from other sub-teams. These are the base requirements by FSAE regarding
accumulator container [2]:
AF4.8 Accumulator Container (EV cars)
AF4.8.1
Load on the Accumulator container structure is applied by loads located at the centre of
gravity of each section of cells/segments. The magnitude of the loads is the mass times
acceleration.
AF4.8.2
Apply the following accelerations for a chassis that separates the Accumulator from the driver
by structure equivalent to “side impact structure”.
a. 20g in the longitudinal direction (forward/aft)
b. 20g in the lateral (left/right)
c. 20g vertical (up/down) direction.
AF4.8.3
Chassis that separates the driver from the Accumulator with side impact structure must use
an “impactor circle” with a diameter equal to the minimumwidth or height dimension of the
accumulator.
NOTE: the impactor circle is used to define the maximum gap allowed for side impact struc-
ture and to distribute side impact loads. AF4.8.3 only applies to side impact structure between
the driver and the accumulator.
AF4.8.4
Apply the following accelerations for a chassis that does not separate the Accumulator from
the driver by structure equivalent to “side impact structure”.
a. 40g in the longitudinal direction (forward/aft)
b. 40g in the lateral (left/right)
c. 20g vertical (up/down) direction.
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5.6.1 Container Design
Initial design of the container was to place all the segments together in one place. This design has advantage
of having less components and centralised system. Therefore, the twomain power cables from the container
can be directly connected to the inverter to drive the tractive system. Additionally, one container design saves
up a fair amount of space as the whole container can be densely packed and mounted on chassis at one part
of the flooring (12 bolts to be used in the design).
However, there are drawbacks to this design which lead to an eventual change in design. First major
drawback is the maintenance safety. The whole pack of assembled accumulator can weigh up to approx-
imately 90kg and thus carrying such heavy and large object can be hazardous to the team members. This
problem exists especially for the fact that FSAE rule requires the whole accumulator container to be lifted
out of the car and placed on the charging cart every time the battery requires charging.
Second issue would be fitting the whole accumulator system into the car chassis. Technically, the whole
container can be taken out from the chassis by lifting the car and releasing the container from the bottom
of the car. However, as a team, it was decided that such method was not the safest option and with the
addition of the fact that the container weighs approximately 90kg, another method was implemented. To
overcome the problem, the container was separated into 3 different containers. One container consisting
of two segments and other components such as pre-charge circuit which will be directly connected to the
inverter and two identical containers with three segments and necessary components such as relay and LED
indicators.
The new container design (3 containers) could then be removed by detaching the driver seat and remov-
ing the container one by one. It still was not particularly easy to remove but with the placement of the
accumulator behind the driver seat, it was deemed to be the most viable option.
Another problem with the configuration was the cabling of the containers. Since the car needs to be
balanced in terms of weight to keep a good centre of gravity. The left and right side of the car must be as
symmetrical as possible. Therefore, the central container which contained the essential circuitry for connec-
tion to the invertermust be placed in themiddle since it is the irregular ones out of the three containers. The
containers, however, must be connected in series with the middle one being both the input and output of
the system. As a result, cabling became disordered and can also be unsafe due to high current properties and
the potential of electromagnetic distortion caused by the flowing current to other systems such as the Low
Voltage components.
Just before freezing the chassis, another major design change was implemented to the car. It was also
decided that the 2017 MUR-E team would no longer be competing in FSAE 2017 but instead it would be a
development to the 2018 car. This decision brought some advantage in terms of design perfection as more
time was available. Therefore, design was reiterated more times to improve both overall safety and perfor-
mance of the car.
Figure 25: Top view of the final accumulator container design[40]
The integration team and other members deemed that the car was unnecessarily long. The biggest con-
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Accumulator
straint to the length of the car was the accumulator container. Because of this issue, the container was once
again redesigned. The containers were then moved to each side of the car and the design became separated
into two containers instead of three. While it did make the car shorter, it made the car wider. This design,
however, made it easier and safer to the electrical assembly of the accumulator. Instead of having once cen-
tral container in the middle, each container acted as one connection to the inverter (one container acting as
input and one container acting as output).
5.6.2 Thermal Analysis
Thermal analysis was done in conjunction with the Brakes, Drivetrain and Thermal sub-team. It was de-
signed that the accumulator systemwill have twomethods of cooling, passive and active. The passive cooling
is done by heat dissipation to the segment fins which act as both structure and heat sink. As for the active
cooling, fresh air will enter the segment through the sidepods and container inlet. The sidepods were de-
signed by the aero team such that continuous airflow will enter the container as the car is moving forward.
As it can be seen on Figure 25, the container is fitted with 4 fans, giving each segment its dedicated forced
convection cooling. The fans act as exhaust to draw out hot air and let fresh cooler air inside the system,
keeping the container and segment cool at all times. Please refer to section 6.8 for cooling testing result.
5.6.3 Extra Safety Measures
Additional safety measures were also added on top of the FSAE rule to provide a much safer system. Those
measures includeVoltmeter, LED light indicator, higher rated cable and current limitation from the inverter.
5.7 Tractive SystemWiring
Figure 26: Tractive SystemWiring Diagram
There are many safety components in the electric race car that interrupt the continuity of the circuit, result-
ing in a fault and openingthe contactors. One shutdown button is on the dashboard, the inertia switch
is under the dashboard, the brake over travel switch and brake system plausibility device are at the pedals.
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Both master switches are located on the right side of the motor bay, and a shutdown button is located on
both the left and right sides of the motor bay. During a fault in the shutdown circuit, both the positive and
negative poles of the battery high voltage are opened, eliminating the high voltage system from conducting.
The high voltage connectors have safety interlocks that open the shutdown circuit when the high voltage
connectors are removed from the battery boxes, eliminating contact with the high voltage system. The two
master switches will remove the low voltage supply, and open the accumulator isolation relays (AIRs) when
switched off. If the circuit is opened by the BMSor IMD, the circuits latch, and the tractive system is disabled
until manually reset by a person other than the driver. The driver cannot reactivate the tractive system with
cockpit controls and cannot physically reach the reset buttons in the rear of the car. [2]
5.8 High Voltage Disconnect
Figure 27: TE Connectivity’s AMP+Manual Service Disconnect[41]
Many high-voltage energy storage systems include a safety feature that is called the high-voltage interlock
loop (HVIL). The HVIL creates a closed circuit when the battery pack is sealed; if one part of the pack is
opened, the circuit is broken, and the contactors are opened to prevent current from flowing. The HVIL is
a series of components, software, and controls along with an integrated pack design that will not allow for
the pack to be opened until the HVIL is disengaged. This ensures that the system is safe to work on when
it is opened for service or maintenance. One way of doing this is to use a high voltage disconnect (HVD)
device that has a fuse integrated into it. Once the HVD is removed, the circuit is opened, and voltage will
cease to flow.[16]
FSAE rules require the use of a high voltage disconnect that can quickly disconnect at least one pole of
the tractive system.[2] This is also known as a Manual Service Disconnect (MSD), which when open can
remove any voltage between positive and negative accumulator terminals. An untrained person must be
able to remove the HVDwithin 10 seconds, it should be clearly visible and require no tools to open.[2]
TycoElectronics’AMP+Manual ServiceDisconnect is selectedwhich is tool free and is finger actuatedby
a two-stage lever to open the circuit and prevents current from flowing.[42] This way it protects the battery
pack high voltage cables from short circuiting. The device has conductive pins that complete a circuit when
fully seated and allows current to flow. Its fuse is rated for 350A [41] and as our maximum current will be
200A, this ensures that the HVD can safely do its job.
5.9 Tractive SystemMeasuring Points
These must be installed next to the master switches as per the FSAE rules. Pomona Electronics 72930 4mm
banana jacks rated to 1kV have been used for the HV+ (red) and HV- (black). These are connected to the
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Accumulator
positive and negative motor inverter lines respectively. Johnson / Cinch Connectivity Solutions 108-0903-
001 4mm banana jack is used for GLV (Low Voltage Ground) measuring point.
(a) 4mm Banana Jacks [2]
(b) IP65 rated Protective Cap [43]
Figure 28: Comparison of the signals in the frequency domain
Thesemeasuring pointsmust be protected from the rain, dust and accidental touching. For this purpose,
they are all fitted with a protective cap that is IP65 rated.
5.10 Tractive SystemMaster Switch
When the Tractive System Master Switch (TSMS) has power the three emergency shutdown buttons will
be functional and accessible to either the driver or on the left/right sides of the vehicle. When this switch is
shutdown no power remains in the tractive system as the accumulator isolation relays are open. After this,
the key can be taken out for safety purposes by the electric safety officer on the team.
Figure 29: TSMP and TSMS
This switch will also have a lock on it to prevent unauthorised personnel from turning the car on. This
lock is needed because the key used is commonly used formany different switches and there is a good chance
that on competition day, a malicious person could try and turn the car on. Having a lock with a key on it
prevents that. This lock is fitted onto the switch by taking the key out and drilling a hole through the switch
so that when the lock is put on, a key cannot be physically inserted into the switch.
5.11 Charge Cart
This was a junior project led by the Accumulator sub-team. Five junior members were part of the charge
cart team. The goal was to build a charge cart that can be used to transport the battery pack and cells, both
on the competition day as well as during the development of the battery pack.
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5.11.1 FSAE Rule Requirements
As per the FSAE rules section EV 8.4, a charge cart must be provided by a team that registers for the FSAE
competition. This cart must have a brake that can only be released by using a Deadman’s switch[2]. A
Deadman braking system is commonly used in Airport trolleys, where a handle must be pushed down to
release the brakes. This brake must also be able to stop the fully loaded cart[2]. The primary use of the cart
is that it will be used to charge the accumulator containers as it is a requirement that the containers must be
taken out of the car before charging[2]. This is a safety requirement which ensures that if things go wrong
and the battery pack catches fire, there is less damage.
5.11.2 Cart Dimensions
To help design the cart, the Accumulator sub-team held weekly meetings with the charge cart team to del-
egate tasks and help select the correct parts that meet the requirements. The cart has space for a laptop and
two chargers that will be used to charge each accumulator container. The accumulator containers have a
space on the bottom of the cart. This helps place the accumulator containers onto the cart with ease as each
container weighs about 45kg. If these were placed on top, it would have been unsafe and very difficult for
personnel to place the containers on top. The cart has an overall dimension of 1100mmx 1000mmx600mm.
Figure 30: Charge Cart
5.11.3 Material Selection
The team initially considered steel, iron, and aluminium. Ultimately however, aluminium was chosen for
the following reasons.
• Firstly, aluminium is a lightweightmetal. In other words, it is not very dense and has a “high strength-
to-weight” ratio[44]. Thismeans that a cartmade using aluminiumwill enable it to be light inweight
while still maintaining a good load-bearing capacity, which is ideal since the fully-loaded cart will have
to be pushed uphill on a gravel path on competition day.
• Aluminium is also corrosion-resistant. One of the team’s aimwas to design a charge cart that the club
will be able to use for at least a few years. Since the cart might be stored in an area with potentially
damp conditions, it is important to have the cart that can withstand these conditions. Steel does not
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fulfil this criterion, as it is not corrosion-resistant unless painted or treated and these measures cost
extra. Therefore, choosing a corrosion-resistant metal like aluminium will save cost and time.
• Third is the ductility. Aluminium is a ductile metal with a low melting point. This means that it can
be formed quickly, hence reducing processing time and allowingmore time to perfect the cart’s design.
In addition to this, having a metal that is flexible will give one the freedom to make different shapes,
whereas using steel will put it at risk of cracking during the process[45].
• The final factor taken into consideration was the cost of all the metals. Although the cost per pound
of steel is less than that of aluminium [45], using steel would need extra processes and treatments to
make thecart. This will not only be time-consuming, but will end up costingmore than if aluminium
was used.
5.11.4 Wheel Selection
The first aim was to find wheels that were big enough to push the cart uphill with ease. To ensure the
durability of the wheels, it was also important to choose casters of a suitable material. Between rubber,
plastic, polyurethane and steel, polyurethane was initially chosen to be the best material, due to it being
stronger than plastic and rubber, yet cheaper than steel.
(a) Initial Selection[46] (b) Final Selection[47]
Figure 31: Caster Selection
The team found a company, Tente, that manufactures and supplies casters and had a supplier in Aus-
tralia. Thiswas important as a lot of casters originally selected proved impossible to buy inAustralia. Initially
the team selected LINEA safety 592DUAP100L51-11 RAL9002 polyurethane caster but it was only 100mm
in height[46]. Since, it was necessary to have casters that were big, the team switched to the next best caster,
Tente’s 349DUFP160P67 rubber caster, which was 160mm in height[47].
Unfortunately, because of delays byMUR’s supplier, the team could not build the charge cart in time.
5.12 Accumulator Indicator Light
Accumulator Indicator Light (AIL) is used to detect the closed voltage level of the accumulator system in-
side a container if it is higher than the threshold voltage of 60VDC. This is made to comply with FSAE rule
guideline below:
EV3.3.9[2]
Each accumulator container must have a prominent indicator, such as an LED that will
illuminate whenever a voltage greater than 60VDC is present at the vehicle side of the AIRs.
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In terms of design situation, 2017 EV cars will have two accumulator containers each located on the side
pod of the car. Each of the containers will consist of 48 cells connected in series, with the maximum voltage
of 173V. As this voltage is considered as a class B voltage (refer to Appendix), it is considerably dangerous as
an accident short can lead to a disaster. The accumulator indicator light act as a first barrier indicator towarn
the users if the voltage greater than 60V DC exist at the end of accumulator contactor terminals. The final
design of AIL is implemented in the printed circuit board as shown in Figure 32 below:
Figure 32: Accumulator Indicator Light PCB
5.12.1 Design Considerations
When the AIRs inside the accumulator were closed, the tractive system voltage will be equal to the accu-
mulator batteries voltage. At this stage, all high voltage power line system in the car will be active and the
car is ready to be driven. To let the users know that the accumulator and tractive system is active from the
outside, the AIL will turn on at the container. AIL also active during accumulator charging when the AIRs
are closed, that is when the accumulator charger are connecting to the batteries. A schematic diagram to
illustrate the operation process is shown in Figure 33 below:
5.12.2 Schematics andWiring
Figure 33: AIL Schematic
The circuit consists of two separated sections or grounding area that are electrically isolated through an op-
tocoupler to protect the LVparts from shorting theHVparts. Optocouplers are used since it allows the high
voltage to remain electrically isolated while transferring the electrical signal between two-isolated circuits by
light [48]. This choice helps the low voltage system made by the other team to remain confined from any
high voltages damages affecting the system.
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5.12.3 HV Section Schematic Analysis
From the schematic, the HV+ and HV- on the tractive system is connected to the Vin terminal of AIL
circuit after the main contactors / AIRs closes. The capacitors on the circuit act as a decoupling capacitor
between positive and negative power terminals. The next bit is the Zener diode at the HV+ terminal that
acts as a voltage shifter to prevent voltage smaller than 60V from activating the circuit. This operation can
be illustrated from the Figure 34 below:
Figure 34: Voltage Shifter[49]
When the input voltage is equal and greater than Vzener, then Vout will increase as Vin increases. The
Vzener in this case is chosen to be equal to 51V. In the next part, the linear regulator (LR8) is used to power
the optocoupler. From the datasheet, the linear regulator only starts operating from minimum voltage of
12V to give output voltage of 5V. However, during the experiment, it is found out that an input voltage of
8V is enough to give an output voltage of 4V to indicate digital logic HIGH. So, combining the Vzener and
Vmin of linear regulator, we get Vin to be 59V, which is close to 60V.
Next, the 4V signal is checked at theVout andused to trigger the optocoupler. It is given that the forward
voltage of the diode inside the optocoupler is limited to 1.5V. So, resistor divider was created to down convert
the signal from 4V to be around 1V. The transistor side of the optocoupler will close as it detects this signal.
5.12.4 LV Section Schematic Analysis
The LV section is divided into two parts. One is the LED as an accumulator indicator side and another one
is Vout signal for the LV team to control the Tractive System Accumulator Light (TSAL). It is powered by
5V low voltage battery that is connected from outside the accumulator container. The MOSFET act as a
switch to control the LED. Whenever the optocoupler received voltage greater than 60V, it will close the
transistor side of optocoupler, which eventually power the MOSFET and turn the LED on. At the same
time, 5V signal will be sent to Vout pin to notify the Low Voltage board made by another sub-team.
5.12.5 Safety Extension
In addition to AIL, the 2017 Accumulator team initiate an extra safety feature to caution the users of poten-
tial hazard in the accumulator container. As the battery cell container is likely to be openedduring inspection
ormaintenance, i.e. when there is a problemwith the cell, the users need to bewarned about the voltage level
of the battery that time. To accommodate this, a voltmeter as shown in Figure 35 below is installed at the
contactor’s terminal. This ease the users to monitor the battery voltage and prevent them from accidentally
touch the terminals.
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Figure 35: Voltmeter
5.12.6 Component Placement in the Car
Figure 36: Accumulator Indicator Light Placement
The AIL is located inside each of the accumulator container as shown in container diagram 36 above. The
positive Vin will be connected to one of the AIR and the negative Vin will be connected to the other one.
Once the AIR is closed to power the tractive system of the car, the AIL will work and turn on the indicator
light if the voltage of the container is above 60V.
5.13 Precharge Circuit
5.13.1 Overview
The pre-charge circuit is used to protect the motor inverters and some other components from a very large
inrush currentwhen connected to the battery at the beginning of starting the car. This is because the inverter
has an internal capacitor, which can be damaged from this inrush current when connected directly to the
battery. To implement this, the pre-charge circuit is required to charge the tractive system to at least 90% of
345.6VDCmaximumvoltage before the secondAIR is closed (FSAERule 2017 - EV4.11.1) [2]. The contactor
in the pre-charge circuit (second AIR) is controlled by the LV system through TSMS. The diagram of the
connection between battery and motor inverter is shown in Figure 37 below:
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Figure 37: Battery and motor inverter connection (Taken from Bamocar datasheet [50])
From the diagram, K2 switch will close for few seconds until the voltage (+UB) on the inverter (BAMO-
CAR) reaches 90% of maximum battery voltage. The battery will be connected to the inverter through the
pre-charge resistor. Afterwards, the switch K1 will close and the stabilized current from the battery will now
go through F1 fuse to the inverter instead of K2. As a result, the inrush current will be prevented, and the
invertercan operates properly.
5.13.2 Design Consideration
When choosing the pre-charge resistor, some considerations are considered. The battery voltage was given
to be 345.6VDC and the capacitance of the inverter was given to be 320µF . The calculations below is then
derived to find the resistor value and time needed for the inverter / tractive system voltage to reach battery
voltage. Most of the panel mount resistors in the market have the maximum power limit of 50W. So the
closest value of resistor is 2700Ω since (V 2/R = 45W < 50W ).
Vbatt = 345.6V, C = 320µF, R = 2700Ω, VC = 90% × Vbatt = 311.04V, τ = R × C = 0.864
VC = Vbatt(1 − e−
t
τ )
311.04 = 345.6(1 − e− tτ )
0.1 = Vbatt(1 − e−
t
τ )
t = 2sec
So, the resistor value is 2700Ω and the time needed for inverter voltage to reach 90% of battery voltage is
2 seconds. Plotting the pre-charge circuit into MATLAB, the graph 38 shown below is obtained for both
voltage and current of the pre-charge circuit.
Figure 38: Precharge Voltage vs Time Plot (Left) and Pre-charge Current vs Time Plot (Right)
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It can be observed from the Figure 38 that after 5 seconds the inverter voltage reaches 344V and the initial
current decreases to 0A. So instead of having inrush current of hundreds of Amps that might damage the
inverter, the circuit only receives initial current of 0.128A at time = 0 second, which is far safer.
5.13.3 Component Placement in the Car
Figure 39: Precharge Circuit Placement Inside the Accumulator Container
The pre-charge circuit is located inside the container, parallel with one of the main AIR. The resistor and
the contactor is mounted in a position as shown in Figure 39 above.
5.14 Discharge Circuit
When the tractive system is shut down, the motor essentially turns acting as a power supply that produces a
reverse charging current back to the battery. However, since the AIRs (K1 and K2) are open from the shut-
down, the motor will be in an open circuit state. There is not pathway for the current to flow from outside
the motor, except to the motor internal resistance (R-ZW). The problem is that this internal resistance is
very high that it needs a very long time for the inverter too discharge all its energy to get back to 0V. The
FSAE rule 2017 requires that the voltage in the tractive system (inverter) drops to below 60VDC under 5
seconds after the AIRs are open. It also requires that all accumulator current flow must be stopped imme-
diately during this stage. To handle this problem, the discharge circuit was used to let the energy stored in
the motor be safely discharged after the tractive system is being shut down.
5.14.1 Design Consideration
During the implementation, a slight change was made to the original pre-charge circuit. Extra AIRs K3 and
K4 were added and a discharge resistor was also placed in parallel between the battery and the inverter. The
diagram of the circuitry is as shown in the Figure 40 below:
Figure 40: Precharge and Discharge Circuit
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When the shutdown circuit is opened, the AIR switches K1, K2 andK3will be opened. As a result, there
is no current from the accumulator battery to the inverter (BAMOCAR). K4 will be closed and the inverter
will be close circuited to the discharge resistors and the current will start to dissipate. The voltage of the in-
verterwill start decreasing from initially around 345.6VDCto0VDC.Thedischarge resistorwas chosen tobe
like the pre-charge resistor to simplify the purchasing. However, initial calculation was performed to ensure
the panelmount resistor capable to discharge the battery under 5 seconds and safe under certain power limit.
Calculation:
Vbatt = 345.6V, C = 320µF, R = 2700Ω, VC = 90% × Vbatt = 311.04V, τ = R × C = 0.864
VC = Vbatt(e−
t
τ )
60 = 345.6(e− tτ )
0.16 = e−
t
τ
t = 1.59sec
Plotting this calculation intoMATLAB, we obtain:
Figure 41: Discharge Voltage vs Time Plot (Left) and Discharge Current vs Time Plot (Right)
From the plot in Figure 41, it can be observed that the inverter voltage dropped to 60V in about 1.5
seconds. The voltage also dropped to 0V within 5 seconds. In addition, the current also showed the same
characteristic with pre-charge circuit where it dropped from 0.128A to 0A under 5 seconds. With this, the
inverter can safely discharge all its energy when the shutdown circuit (AIR) is opened under 5 seconds.
5.14.2 Component Placement in the Car
Figure 42: Discharge Circuit Box
The discharge circuit is located outside the accumulator container and located near the inverter. A box was
created to put this circuitry inside. Inside this box, theHVD is also located and attached the wall of the box.
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6 Design Implementation and Testing
Tomake the design functional, components were manufactured and integrated to the accumulator system.
This section thoroughly explains how the components were manufactured, assembled and placed into their
respective location. However, the 2017 Accumulator sub-team focused more on the development of each
individual tractive system component and its testing, and implementation on the car itself was not done
because of delays in the development of mechanical systems of the car. This will be done by the 2018 Accu-
mulator sub-team.
6.1 Manufacturing
Manufacturing plays a key role in the FSAE race car development. Since the parts are custom designed and
cannot be bought off the shelf, manufacturing is a crucial andmandatory process. Some of the manufactur-
ing were done in-house in university/TAFE and outsourced to sponsoring manufacturing companies.
In terms of manufacturing, the mechanical parts form most of the components submitted. This is be-
cause the structure of the accumulator differs fromone car to another based on the type of cells used. In 2017
accumulator project, the cells used were of the pouch type. The size restriction and alignment will differ if
prismatic or cylindrical cells were used instead. As a result, parts to be designed and made would differ as
well. Thus, manufacturability is a big constraint on the design as well since irregular componentsmight help
with theoretical values but might not be able to be implemented in real life situation.
As per electrical components,most of themcouldbe easily bought as they require certain standardisation
and their size are considerably small to be fitted into the car without violating the size restriction. Some of
the electrical components that were bought off the shelf include relay, plugs and fuse. However, some of the
electrical components need to bemanufactured and customdesigned aswell. An example of amanufactured
component is the AIL (Accumulator Indicator Light) as the circuitry needs to be self-designed and hard
wired to indicate the presence of voltage higher than 60V.
Unfortunately, the manufacturing process did not go as quickly as expected. This issue occurred due to
various reasons.
Firstly, the design process delayed the manufacturing process significantly. Due to delay and problem of
design from other mechanical subteam, the timeline was shifted back significantly. The design could not be
finalised until every subteam can prove that their design is deemed to be adequate and has good Factor of
Safety value. As a result, some manufacturer deadlines could not be fulfilled in a timely manner.
Secondly, there were not enough resources to produce two cars at the same time. Since this year MUR
is developing both electric and internal combustion car at the same time, the resources were limited as the
sponsorship andmanufacturing quota was exactly the samewith the previous year where only internal com-
bustion car was produced.
Thirdly, due to issue with the sponsor, one main sponsor decided to stop manufacturing components
for MUR and the third batch of manufacturing were not done at all. It was unfortunate because the third
batch contain most of the components both for electrical and combustion car. As a result, the components
could not be made, assembled and testedat the time this report was written.
6.1.1 Transforming Design for Manufacture Process
In order to manufacture the design accurately, several engineering drawings were developed for different
components to bemanufactured. These documents assist the person handling themanufacturing especially
when the components are outsourced to another place where the designed could not monitor the process
personally. Additionally, these documents can be used for reference and to check the accuracy of the result
of manufacture.
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• The following documents were developed to provide dimension and procedure that should be done
when making the CAM file for CNC machines. These three documents in particular are the specifi-
cations of the cell interconnection of Aluminium, HDPE and Copper in order as it is written.
Figure 43: Engineering Drawing for Aluminium - Cell Interconnection to BMS
Figure 44: Engineering Drawing for HDPE - Cell Interconnection Insulation
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Figure 45: Engineering Drawing for Copper - Cell Interconnection Terminal
• The following document was developed to provide dimension and procedure that should be done
when laser cutting the aluminium sheet. The document also provides the bending parameters such
as direction, angle and tools that should be used when bending the material. Lastly, the document
provides the overall final product of the manufacture so that the outsourcing company can refer to
the design and check whether the job was done correctly.
Figure 46: Engineering Drawing for Aluminium segment fins
Each different methods of manufacture used will be discussed on the next section.
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6.1.2 Laser Cut Components
Several components weremade by laser cutting as it provides high precision and capability to cut shapes that
are irregular. The components that were laser cut include segment fins, acrylic plates and spacers and acrylic
component of the drilling jig.
Due to its accuracy, laser cut components were designed as if they were the actual dimension as opposed
to 3D printed components where a tolerance of about 2mm is required to ensure the parts fits perfectly.
However, laser cut has its drawbacks such as the limited cutting mechanism to flat surfaces only and the
limited material choices (both thickness and types).
Figure 47: Acrylic laser cut component for the Low Voltage Battery
6.1.3 Water Jet Components
Like laser cutting, water jet components cut in two-dimensional movement. It can only therefore be used
on a flat surface. Although less precise, water jet cutting can cut a much thicker material compared to a laser
cut. As an example, the tabs used for segment assemblywere allmanufactured bywater jet. The components
have thickness that varies from 6mm to 19mmduring this phase ofmanufacture. Suchmethodwas required
to manufacture the tabs as laser cutting tools available do not have the power capability to cut beyond 4mm
metal.
Figure 48: Aluminium tabs after being water jet cut and CNCmachined
6.1.4 CNCMachined Components
Other than laser and water jet cut, some components need to be made in three-dimensional motion. When
such requirement is present, CNCmachine is used.
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CAM training were done before manufacturing any components using CNCmachines. Both the train-
ing and manufacturing were done in Holmesglen Moorabbin TAFE. The components were made from
scratch based on the design and raw material block. In terms of accumulator use of CNC, there were not
many. Some of the examples where CNCmachines were used are the tapping of tabs to provide connection
to the BMS and the old tabs components where the shape was of a four-sided angled prism.
6.1.5 3D Printed Components
3D printing was usedmainly for prototyping as the tolerance of 3D printed component is not very accurate.
Also, PLAwas the onlymaterial available to be used for 3D printing. The component, however, can be used
as a model for the actual design before further implementation. Components that were 3D printed include
the top assembly and bottom assembly of the cell interconnection.
6.1.6 Components using hand tools
In addition to all the other methods used, some components were altered and made by using hand tools.
The components done by hand tools were mainly the jigs which is a supplementary component for testing
and assembly. The jigs will not be placed into the car itself but mainly used tomake repetitive process faster.
6.2 Assembly
6.2.1 Segment Assembly
Once the components were made and ready to be used, segment assembly was conducted under the super-
vision of a professional electrician. The assembly was done by following the SOP which was reviewed by
Melbourne University OH&S. Thus, the processes were clearly indicated and done with care.
Figure 49: Accumulator segment prototype being assembled
The cell tabs were drilled at a precise location to align and connect them with the manufactured alu-
minium, HDPE and copper tabs. The drilling was done with the help of the jig that was produced before
the assembly process started.
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Figure 50: Jig made to create precise hole on the cell tabs
After the segment was assembled, however, it turned out that the cell interconnections do not have a
strong enough pressure from the threaded nylon rod. Nylon itself was chosen due to its insulative material
to prevent accidental short between the terminals.
As a result, a clamping mechanism was developed by using a heat-shrunk steel rod with 4mm insulated
steel plate at each end. The design was discussed through with the professional electrician and integration
team. The following picture shows the prototype of clamping mechanism by using 3mm aluminium and
3mm steel:
Figure 51: Prototyping the mechanism of cell tabs clamping
As it can be seen, the metal could not withstand the force generated by the nut and therefore a thicker
and stronger material (4mm steel) was used.
6.2.2 Low Voltage Battery Assembly
As mentioned previously on the design section, the low voltage battery was made slightly different than the
full 12 cells segment. The low voltage battery has full structure made up from acrylic which are clamped
together with 6 M6 bolts. Unlike the tractive system battery pack, the Low Voltage Battery will only draw
a maximum current of approximately 5A. Thus, cooling system is not necessary as the battery will not heat
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up when used in the system. The battery was run nonstop for a couple of hours when testing the BMS and
Low Voltage System and no notable increase in temperature was observed.
Figure 52: Low Voltage Battery integrated with BMS and LV System
The BMS system is also implemented on the Low Voltage Battery. The relay will shut down the system
if a single cell goes out of the voltage range of 2-3.6V and if the total voltage of the LowVoltage Battery goes
out of voltage range of 10-14.4V. In addition, the LV Battery is also fitted with temperature sensor with the
same specification of the main segment, which will shut down the system if the temperature goes above 55
degrees Celsius.
6.2.3 Container Assembly
The container was still under development and was not ready to be assembled at the time this report is writ-
ten. However, when implemented, the container will be firstly coated with Nomex 410 to ensure electrical
insulation that complies with the FSAE requirement and maximum rating of the accumulator system. Ad-
ditionally, Nomex 410 will also protect the container in case of fire which complies with the rating of UL94
V-0.
6.3 BMS Implementation to the segment
As the segment was completely assembled, the BMS system was then installed to the system. As mentioned
previously, the cell tabsweremadewith tapped holes to accommodate the connection to the BMS.TheBMS
consists of a temperature sensor and a voltagemonitor. As the FSAE rule requires the temperature sensor to
be at amaximumdistance of 1cm from the negative terminal of the battery cell, the sensor isdirectly attached
to the aluminium tabs alongside the voltage monitor.
Figure 53: BMS connection on the segment tabs
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6.4 Further implementation
Further implementation is currently undergoing and will be done during the start of 2018 during and after
the handover takes place. To assist the 2018 team with implementation, materials were purchased and made
available.
6.5 Cell Testing
Cell testing was conducted as part of an experiment to investigate the health-state and performance charac-
teristic of the battery cell. It was also performed to determine whether the cells are compliant to the data
sheet and to hunt for poorly performing cells before putting them together inside the EV car. Four battery
issues that often become an agent of battery failure are declining capacity, high internal resistance, inflated
self-discharge and voltage premature cut-off [51]. By analysing these 4 major aspects through cell testing,
the risk of having defective cells inside the accumulator can be minimised, thus eliminating the hazards and
performance degradation prior to the battery pack assembling.
The experiment begins from designing andmodelling the load bank, which is used to imitate the power
drawn from the batteries to the inverters (motor controllers). This is later completed through the process of
individual cell acceptance testing to determine the outcome on how good the cell is.
6.5.1 Individual Cell Acceptance Testing
One of the methods that NASA used for cell acceptance testing for Li-ion battery is soft short test, which is
to deep discharge the batteries to end of discharge voltage (EODV) and leave it for 14 days to observe the open
circuit voltage (OCV) to bounce back [52]. In this experiment, the discharge-cell testing will be conducted
through a single load bank that can draw the current up to 200A.
To perform this testing, the process of the current discharge is configured into two different meth-
ods, which are continuous discharge and pulse discharge testing. In continuous discharge testing, the fully
charged battery cell will be pushed to discharge its maximum current until its nominal voltage drops to its
minimum voltage threshold. When the battery cell reaches this voltage (EODV), the discharge process is
terminated, and the battery will be left inside a container for 14 days. After 14 days, the battery voltage will
be measured, and the data is obtained. For pulse discharge testing however, the battery cell will be config-
ured to discharge at certain amount of time (5 to 10 minutes) and pause for a brief period (1 minute). These
repeating processes will take place over and over until the battery cell is depleted (reaching its EODV). The
motivation for testing is:
• Toobtain the characteristic of cell voltage versus time under different discharge current (to test voltage
stability and premature cut-off voltage).
• To observe the capability of battery cell voltage to bounce back to its nominal voltage
• Tomeasure the cell’s internal resistance
• To obtain data on temperature versus power that Thermal Team will use to design and analyse the
cooling system.
• To gain graphical information for cell modelling and SOC estimation that will be used by BMS (Bat-
tery Management System) team
6.6 Load Bank 2016
6.6.1 Prototype andModel Development
To do the single cell testing, the load bank to discharge the battery cell was designed and built in-house to
increase the degree of measurement flexibility (increasing options to draw howmuch current) and to reduce
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the incurring cost from having multiple load banks for different discharge rate. The junior 2016 team has
started with the casing design of aluminium tube enclosing the load bank with a small fan attached at the
end of the tube.
In early January 2017, The Accumulator 2017 team took the design to its completion process by adding
small circuitry and sensors to the load bank and use it as an initial prototype to test the current discharge
for only up to 132A theoretical value. Arduino Ethernet was used as the microcontroller, since it can be used
for data logging through SD card. Connected to the microcontroller, there are 3 sensors that are used in
this testing, such as voltage sensor, current sensor and temperature sensor. The process of operation can be
explained from the schematic of the circuitry as shown in Figure 54.
Figure 54: Load Bank 2016 Schematic
6.6.2 Procedure and Technicality
From the circuit, there are 12 resistors that are used as the load for discharge current. Each of the resistors is
rated at 0.3Ω (50W). From the configurations, four resistors are separated individually and its connection to
the battery cell is controlled by a single MOSFET that are connected to microcontroller through pin P1, P2,
P3, and P4. The rest 8 resistors are connected in parallel and connected to a contactor that is powered by 12V
supply and controlled by a small 5V relay. The NPN transistor that is controlled by the microcontroller pin
Q1 (Arduino I/O) controls this relay.
The table summarising thepin configurations that themicrocontroller controls togetherwith the amount
of resistance and discharge current that can be obtained from the battery is shown in Figure 55.
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Figure 55: Pin Configuration controlled byMicrocontroller
In obtaining the required data, the analog input pin of Arduino measures the voltage of the battery cell
through Analog to Digital sampling. The current drawn from the battery is measured by the Hall Effect
sensor (current sensor) and later read through the Arduino. Themaximum current discharge of 132A can be
obtainedwhen the status of all pins isHIGH,which iswhen the battery cell is close circuitwith all the parallel
resistors. Lastly, the temperature sensor is attached at the negative terminal of the cell and communicates
using 1-Wire protocol to send the data to the Arduino.
6.6.3 Interfaces
The image of 2016 load bank is as shown in Figure 56 below:
Figure 56: Load Bank 2016
The electronic circuitry was mounted on the load bank together with the isolation relay. The 12V power
supply was obtained through power adaptor, which is soldered through cable to the Veroboard. The resis-
tors are installed inside the covering aluminium and the connection to the battery is using standard single
insulated 125A cable.
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6.6.4 Safety Consideration
Safety is the biggest concern when discharging a battery cell with current can rise to 132A. A small short
circuit contact between the positive and negative terminals of the battery cell can cause an arc flash and severe
injury to the users. This is a similar radiation to welding; whose heat produced may cause several burns on
the exposed skin [53]. A short-circuited terminal on the cell can also cause the cell tab to be destroyed, thus
harming the condition of the battery cell. This safety concern rose after inspecting and analysing the safety
level of the 2016 load bank. Although there have been no accidents occurring, the 2017 Accumulator Team
with support from Integration Team initiated to scrap the old load bank and redesign the new one. This is
to improve the safety factor and to add some features to the load bank for future use. Before redesigning the
new load bank, some analysis and justification on why the 2016 load bank poorly meet the safety criteria of
performing high current cell discharge is elaborated below. The problems with the 2016 version of the load
bank can be divided into two parts, mechanical and electrical.
• Electrical Inspection and Concerns
One of the main problems with the electrical side of 2016 load bank is the connection. Most of the
cables are loosely connected and attached poorly. This is shown in the Figure 57 (red circle) where 4
small cables are relying on a bolt to keep attaching to its connection. A loose connection could cause
the cables to be short circuited, thus giving unexpected outcome, such as destroying another circuitry
inside theload bank.
Figure 57: Load Bank 2016 Loose Connection
• Mechanical Inspection and Concerns
The 2016 load bank also has an issue with the mounting point. Most of the electrical components
are not properly attached. One of the examples is the floating current sensor, which can be seen in
Figure 57 inside the orange circle. Drilling the wall to mount the sensor could cause an issue as all the
components, such as the resistors inside the load bank have been fixedly attached to the wall. Thin
wall casing also causes a safety issue as it causes the load bank to be not rigid and structurally weak.
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6.7 Load Bank 2017
6.7.1 Design andModel Development
One of the purposes to create a new load bank was to provide a safe environment to discharge the current
of the battery cell up to minimum 200A. One of the main designs considerations in this new load bank was
to install the safety devices that can minimise the risks of hazards, such as arc flash and electric shock from
occurring. These safety devices include fuse, emergency button and indicator light. The block diagram of
the 2017 load bank can be seen in Figure 58:
Figure 58: Load Bank 2017 Overall System
Fully manufactured and assembled 2017 load bank can be seen in Figure 59.
Figure 59: Load Bank 2017
The design principle of the 2017 load bank was built based on the success of 2016 load bank in drawing
currents from the battery without overheating or damaging the load bank. The same approach was imple-
mented to the load bank 2017, howeverwithmore careful consideration on safety aspects andmanufacturing
process. From the Figure 59, it can be seen that the battery cell is connected to the load bank, which is then
controlled and read through the microcontroller. However, this time the microcontroller forwards the data
to the raspberry pi for processing and display them to the LCD. These extra features were added and some
explanations on why they were implemented are given below:
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• Real time monitoring using Raspberry pi and LCD
Visual monitoring was implemented to provide graphical image on how much current or tempera-
ture that the battery is currently outputting during the testing. The problemwith previous load bank
is that the user must interpret each raw data that the microcontroller outputting one by one to de-
termine whether the cell performed the testing correctly or as required. With real time monitoring
however, the user can directly monitor the behaviour of the battery cell and perform the emergency
shut down when the cell is overheated or fails to discharge current.
• Parallel resistors
The loadbank also has additional power resistors up to 24pieces that are connected inparallel (12more
than the original loadbank). This allows the same cell to dischargemore than 200Acontinuously, thus
achieving the aim to push the battery to discharge its maximum continuous current (deep discharge)
• Smaller microcontroller size
The microcontroller also has been changed to Arduino Nano for its size and space efficiency. In addi-
tion to that, the data was no longer recorded in the microcontroller, but instead send to the raspberry
pi using UART communication protocol.
• Automatic file generation
The raspberry pi is also coded to be able to generate a real-time data and converted them to the .csv
file at the same time of the testing. This provides an efficient method in extracting and compiling the
data without the need to transfer the data externally using SD card.
The implementation of the overall system is shown in Figure 60 :
Figure 60: Load Bank 2017 Implementation
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6.7.2 Internal Circuitry and Safety
Figure 61: Load Bank 2017 Internal Circuitry
The internal circuitry of load bank 2017 is shown in Figure 61. Some of the main differences with load bank
2016 are the installation of the emergency button, fuse and indicator LED (not shown in Figure 61). In addi-
tion, the load bank 2017 eliminates the use of NPN transistors that control the number of parallel resistors
connecting to the cell.
• Emergency Button
The emergencybutton is connected in serieswith the isolation relay and 12Vpower supply. It is config-
ured to be in a normally closed state, so that once the button is pressed, it will open the circuit between
12V supply and the relay. This causes the current to stop flowing from the cell to the resistors.
• Fuse
The fuse is installed to limit themaximum current of the cell up to 200A. Ferraz ShawmutA50QS200
was chosen since it is rated up to 500Vdc and current up to 200Adc. It is also the same fuse that will
be used inside the accumulator container.
• Indicator LED
The indicator LED is installed to tell the user if the cell is currently discharging or not. A light in green
LED indicates the cell is currently discharging and a light in redLED indicates the cell is not connected
to the resistors.
• Label and Stickers
Lots of the connections in the load bankwere labelled to prevent reverse polarity thatmay damage up
the whole circuitry. Cells and resistors wiring were also labelled to indicate which cell is fully charged
and which resistors are being drawn to.
• Discharge Operation
The discharge operation of load bank 2017 is like 2016, however the process of selecting the number
of parallel resistors connected to the cell is done manually.
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Figure 62: Load Bank 2017 Manual Connection
When selecting how many resistors that are being used, the wires that are connected to those resis-
tors are attached and bolted to the wire connected to the battery cell. Changing the resistors means
disconnecting the red wires in Figure 62 and changes them to another red wire. One of the reasons
to do this mechanically is to eliminate the use of transistors as a switch. Using transistor as a switch
involves soldering the connections to the Veroboard and connecting 3 wires from 3 parallel resistors
to 1 pin of transistor in the Veroboard could increase the risks of short-circuiting. Besides that, a con-
nection using solder is easy to come off whenever a potent force is applied to it. This is problematic
and repeating the same mistakes in 2016 load bank.
• Battery Jig
As an act of safety measurement to prevent incidents from occurring, isolation from high voltage line
is required to contain the hazards. The two terminals of the battery cell must be securely fit before the
testing is conducted. The 2017 team initiated the safety battery jig to accommodate this need. This
equipment will help to locate the battery in a tight position and secure it from moving. At the same
time the non-conductivematerial (in this case a wood) on top of them secure the tabs so that nometal
objects or bare hands can touch it. The tabswere fit into the copper contactors, whichwere bolted and
attached to the red and black cables through metal ring connectors. Then they are clamped together
with a wood block on top of it. This way, the battery is safe to be used and isolated properly.
Figure 63: Battery Jig
• Fan
When designing the battery load, thermal heat excess from the load was taken into considerations.
Excess heat could cause component destruction and is dangerous for the users. In this case, a fan was
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chosen as a suitablemethod to cool down the system. It is one of themost effective ways to cool down
the system and less costly.
Figure 64: Fan placed for Load Bank Cooling
6.8 Testing Data and Analysis
Figure 65 and 66 show the plot graph of Voltage and Temperature versus time for continuous discharge
under different currents.
Figure 65: Plot of Voltage and Temperature versus Time for discharge current 22A and 88A
Figure 66: Plot of Voltage and Temperature versus Time for discharge current 132A and 200A
• Voltage
From the graph it can be analysed that the higher the discharge current, the higher the voltage drop on
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the closed-circuit voltage (CCV) of the battery cell. At 22A, the voltage drop stabilizes at around 3.3Vfor an extended period before sharp decline at the end of discharge capacity. However, when pushed
at 200A, the voltage drops quickly to around 2.5V and keep declining for quite a long time until the
end of discharge voltage. At 132A, the voltage seems to stabilise at 3V before drops down sharply at
the end of discharge voltage. This gives an assumption that the battery cell does not behave well at
high discharge current 200A.
Assuming all cells in a pack exhibit the same characteristics, at 22A, the continuous closed-circuit volt-
age that the accumulator can provide is 316.8V. So, the continuous power output is 6,969.6W. At
132A, the continuous closed-circuit voltage that the accumulator can provides is 288V. The continu-
ous power output is 38,016W.At 200A, the continuous closed-circuit voltage that the accumulator can
provides is 240V. The continuous power output is 48,000W. This information was later forwarded
to EPT team for future design consideration.
• Temperature
From the plot graph, it can also be observed the temperature that a single battery cell can experience
during discharging process. According to the datasheet, themaximum safest temperature that the cell
can reach before cut-off is 60 degrees Celsius.
At 22A, by the end of discharging process, the maximum temperature that it reaches is only around
28 degrees Celsius. It is believed that this discharge current, the ambient temperature played a bigger
role in determining the temperature at the cell’s tab. It can be seen from the graph that the peak tem-
perature at 88A discharge current is around 55 degrees Celsius. This is achieved for a moment during
before the voltage of the battery cell drops significantly by the end of discharge process. At 132A, the
temperature rise is similar with the one at 88A, giving a peak temperature at 55 degrees Celsius. How-
ever, at 200A the discharging process had to stop before the cell reached the end of discharge process
because the cell’s temperature has reached above 60 degrees Celsius. During this time, the emergency
push button was used to end the testing process.
Figure 67: Simulated thermal data on different types of cooling[54]
Figure 67 shows the characteristic of temperature rise analysedby the thermal team[54]whendifferent
types of cooling is used. The red plot shows the increase in temperature when no cooling was used at
all. The three simulation cases assumed that the battery never run out of energywhen fully discharged
continuously. The initial set of data was used based on the actual experiment on discharge at maxi-
mum battery capability which then extrapolated linearly. The blue plot indicate the cooling based
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only on aluminium fins heat dissipation and the yellow plot shows the temperature based on forced
convection by active cooling method. This extrapolated data was used only for showing how active
cooling can decrease the temperature even at an extreme case. The actual battery characteristic would
not heat up to more than 65 degrees Celsius due to surrounding ambient temperature alone and for
the fact that the battery will deplete over time. Additionally, notice that the starting temperature is at
40 degrees Celsius instead of the usual ambient temperature of 28 degrees Celsius.
When implemented to the car, the current drawnwill be limited to 132A.As the testing has shown (re-
fer to figure 66, the temperature reached a peak value of 55 degrees Celsius on this particular discharge
rate. This temperature will be lower due to several factors. Firstly, during race events, the battery will
only be discharged at maximum current rate only for several seconds as compared to a continuous
discharge (until battery finished) during the testing. Secondly, both passive cooling and active cooling
will be implemented, dissipating the heat much faster as opposed to no cooling at all during the dis-
charge test. Thirdly, the actual battery characteristic will not increase as extreme as the extrapolated
data on figure 67 as it was exaggerated for simulation purposes.
This information obtained was forwarded to thermal team for future consideration and analysis to
cool down the accumulator pack during the car racing competition.
6.9 Battery Safety Charging System (BSCS)
6.9.1 Introduction
One of the main concerns during the cell testing is to find a safe method to charge the cell once its capacity
has been depleted. One way to charge the battery cell is to use the power supply, connect it to the battery
cell and specify the recommended charging voltage. However, this process requires the user to continuously
monitor the charging process and checkmanually if the cell has been fully charged. Some of the risks that can
happen when the battery cell is left charging for a lengthy period are reverse polarity and overcharging. To
prevent this, BSCS is made to continuouslymonitor the battery voltage and automatically stop the charging
once the cell is detected to be full.
6.9.2 Risks and Safety
• Reverse Polarity
When charging the battery cell, there have been frequent events where the connections from the
power supply were connected to the wrong terminal of the battery cell. This accident often happens
due to a very small label of positive and negative terminals on the battery cell that can be easily over-
looked when small attention was given. Fortunately, there has not been major accident happening in
the last few months due to the safe lab equipment, in which the power supply bought specifically for
the battery cell charging has an in-built reverse polarity protection. This cut-off the connections to
the battery cell whenever the reverse polarity is detected.
However, reverse polarity is still an undesirable situation since an accident connection of lithium bat-
tery to another power source in the same circuit may cause a risk of fire or explosion [55]. For the
chosen battery of A123 System, the accompanying datasheet confirmed this warning by specifying
that the cells should not be exposed to a reverse polarity or short-circuited [26].
The BSCS prevent this risk by similarly implementing a reverse polarity protection circuit that cut off
the connection whenever reverse polarity is detected.
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Accumulator
Figure 68: 20A Power Supply
• Overcharge
Charging the cell may take many hours until the battery cell is full. With a normal power supply
supplied by the University, the maximum current that it can generate is only limited up to 2A. In
other words, it may take around 10 hours for the battery cell to be fully charged. In addition, with
the new power supply that can generate up to 20A, it still takes up to 1 hour for the battery cell to be
full. Waiting for this prolonged period can often lead the battery to be overcharged. Overcharging
the battery cell could cause the battery cell to undergo the process of plating (deposition of metallic
lithium), where the transport rate of Li ion to the graphite negative electrode (anode) exceeds the rate
Li can be inserted [51]. As a result, this process can lead to short circuit, degradation of battery’s life
and durability [56].
6.9.3 Charging Characteristic and Safety
When designing the BSCS, the general Li+ battery-charging characteristic as shown in Figure 69 is used as
a basis for design operation. The main problem when charging the battery is that the information about
battery state of charge (SOC) or the current capacity is unknown. Battery voltage alone could not be used as
an accurate point of measurement for the battery’s capacity. As a result, this charging characteristic is used as
a simple algorithm to estimate the battery’s capacity and later implemented into the microcontroller inside
BSCS.
Figure 69: Lithium Cell Charging Characteristic
[]
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Accumulator
It can be seen from the stage 1 that the battery cell is initially charged at a constant current until the
battery voltage reaches its maximum voltage. In this case, the battery cell is assumed to start from a nearly
empty state. All theparameters, such as maximum voltage and current shown in the Figure 69 were only
used as a sample. For A123 cell, the maximum voltage is 3.6V and original starting current is dependent on
maximum current that the power supply can provide. Later, once the cell reaches it maximum voltage, the
charging process is then switched to constant voltage source and the current from the power supplywill start
to decrease. This is shown in stage 2 of the Figure 69. Although the voltage of the battery cell has reached
its maximum, it does not mean that the battery cell is full. So, at this stage, the battery cell will still be left
charging. From the Figure 69, the charging process should terminate when the current going to the battery
decrease to less than 3% from the original current in stage 1. At this point, the battery cell is close to full as
the current going to the battery cell has decreased to negligible.
6.9.4 Design and Final Product
Figure 70: BSCS Schematic
The schematic diagramof BSCS is as shown in Figure 70. The recommended charging voltage for the battery
cell is 3.6V and the relay is powered by a 12V voltage supply and controlled by a MOSFET andMCU.
Figure 71: Battery Safety Charging System
In this design, the touch screen LCD is implemented to provide a user interface to control when the user
wants to start or stop charging the battery cell. The LCD also displays the voltage and the current going
to the battery cell. Besides that, the BSCS also has an LED to give an indicator when the BSCS is active or
currently charging. The image of the final product of BSCS can be seen in Figure 71.
Page 85
Accumulator
7 Conclusion
The Accumulator sub-team started this project with the aim of having a complete battery pack by the end
of the year. As this was the first year that MUR-Electric team, the organisation was not ready to develop
a car and go to the competition this year. A lot of delays because of a lack of High (Hazardous) Voltage
Training, a lack of appreciation of the high standards of safety required to build an electric car which led to
the university’s OH&S team requiring the development of better and safe procedures, and some delays from
mechanical sub-teams led to the Accumulator sub-team under-performing as well. While most goals set out
at the start of the year, a complete battery pack was still not completed, and this would have to be done by
next year’s team.
Despite this, the team did well to develop safety procedures and get through to the MURmanagement
that safety must be the top priority. Cell selection was done keeping the high standards of safety in mind.
Safe cell testing procedures and equipment such as cell testing jig and load bankwere developed. This would
make it easier for the next year’s team to characterise the cells in case there is a need.
From the testing and modelling results, the AMP20M1HD-A cell is found to be safe under a high load
current. However, a very high voltage drop, and a temperature rise when discharged at this high current
might hinder the car’s performance in the long run. Regardless, it can be concluded that theA123AMP20M1
HD-A cell has been proven to work well with the required power and energy for various FSAE events. This
project was focused on making the safest possible battery pack but because of this, it resulted in a heavy
pack. In the coming years, the possibility of using cylindrical cells or high energy LiPo or Li-ion cells should
be considered for designing the battery pack.
Themodule/segment satisfies all the FSAE rule requirements andwhile it presented a lot of challenges in
terms of its design because the location of the battery packwas changed by the Integration sub-team, the new
segment/module design is not only much safer compared to the old design, it is also better at thermal man-
agement. Accumulator container has also been improved extensively. Extra features that were not required
by the FSAE rules were added to the container. These include a voltmeter and a LED light indicator.
This year the teammanaged to complete the design of the major components that were required in the
electric tractive system. In future and especially next year’s teamwouldhave tobuild the other seven segments
that the Accumulator sub-team was unable to build this year because of MUR sponsor’s delay in supplying
the parts to the team. These parts had to be laser cut and bent and could not have been done at the university.
Furthermore, next year’s team can improve the segment design by improving the way the two top plates are
connected. Next year’s teamwould also have to integrate the accumulator packs into the car and further test
them while they are in the car to ensure that everything works as it has been designed. The designed charge
cart would also have to be built before the competition.
Page 86
Accumulator
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information contained herein at any time without notice. TE expressly disclaims all implied warranties regarding the information contained herein, including, but 
not limited to, any implied warranties of merchantability or fitness for a particular purpose. The dimensions in this catalog are for reference purposes only and are 
subject to change without notice. Specifications are subject to change without notice. Consult TE for the latest dimensions and design specifications.
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AMP+ Manual 
Service Disconnect APPLICATIONS
• HV battery pack-to-pack
MECHANICAL
• Latching style: Finger actuated - 2 stage lever assist
• Mating cycles: Tested to 50
• Stud: M6
• IP rating: Mated: IPx7, IP6k9k 
 Unmated: IP2xb 
• HVIL: 2x integrated, internal
ELECTrICAL
• Fuse rating: Up to 630A
• Voltage rating: 450 VDC
• Operating Temperature: -40°C to 65°C
• Storage Temperature: -40°C to 85°C
• Current rating: Based on fuse selection
STANDArDS AND SPECIFICATIONS
• USCAR-2
• USCAR-37
• IEC 60529
• RoHS
PrODUCT OFFErING
• Receptacle Assembly Part Number: x-1587987-x*
• Plug Assembly Part Number: x-2103172-x* 
(*Different fuse sizes available)
PrODUCT DIMENSIONS
KEY FEATUrES
• Finger actuated - 2 stage 
lever assist latching
• No tool required to unmate
• 2x integrated internal HVIL
• Scalable design
• Current rating determined 
by fuse selection
• Fuse rating up to 630A
• USCAR-2, USCAR-37, IEC 60529, 
RoHS compliant
• Tested to 50 mating cycles
• Sealed
Accumulator
A Appendix
For more appendices please refer to the submitted digital file separated from this document.
A.1 Datasheets
A.1.1 High Voltage Disconnect
Page 91
 
 
Models 72930 
Panel Mt IEC1010 4mm (0.16in) jack for Sheathed Plugs 
USA: Sales: 800-490-2361 Technical Support: 800-241-
2060 Fax: 888-403-3360 
Europe: 31-(0) 40 2675 150 International: 425-446-5500 
e-mail: technicalsupport@pomonatest.com 
Where to Buy: www.pomonaelectronics.com 
All dimensions are in inches. Tolerances (except noted): .xx = ±.02” (,51 mm), 
.xxx = ± .005” (,127 mm). All specifications are to the latest revisions. 
Specifications are subject to change without notice. Registered trademarks 
are the property of their respective companies. 
 
Copyright © 2004 2/2006 72930 Rev A Page 1 of 1 
 
 
 
 
 
Features 
• Panel Mt IEC1010 4mm (0.16in) jack for 
sheathed banana plugs, threaded stud. 
• Hexagonal nut 
Materials 
• Body: Polyamide. 
• Nut: Nickel plated 
• Stud: Nickel brass. 
• Hex nuts: Nickel Plated brass 
 
Ordering Information 
Model: 72930- Color sold in packages of 10 pieces. 
Available colors: Black (-0), Brown (-1), Red (-2) 
Yellow (-4), Green (-5), Blue (-6), Violet (-7), Grey (-8), 
White (-9) 
 
 
 
 
 
 
 
 
 
 
 
 
Specifications 
Max Current 36A 
Max Voltage 1000 V CAT III 
 
M4 x 0.7 nut: Screwing torque nuts 30Ncm Max. 
 
Accumulator
A.1.2 Tractive SystemMeasuring Points
Page 92
1.0
1.0
.88
.53
.91
1.59
2.13
1.58
1.13
.63
.94
.75
1.03
.937
.438
.579
.438
1.07
.94
This product is RoHS compliant.
Audio/Video Connectors
Johnson C
om
ponents
1359
JOHNSON Banana Plugs and Jacks, Binding PostsBANANA PLUGS
For quantities greater than listed, call for quote.
MOUSER
STOCK NO.
Johnson
Components 
Part No.
Fig. Color Amps Max.Wire
Price Each
1 10 25 100 500 1000
Insulated Side Set Screw Solderless
530-108-1702-101 108-1702-101 A Red 15 16AWG 
530-108-1703-101 108-1703-101 A Black 15 16AWG 
Insulated Solderless Tapered Handle
530-108-0302-1 108-0302-001 B Red 15 16AWG 
530-108-0303-1 108-0303-001 B Black 15 16AWG 
530-108-0301-1 108-0301-001 B White 15 16AWG 
530-10803041 108-0304-001 B Green 15 16AWG 
530-108-0306-1 108-0306-001 B Orange 15 16AWG 
530-108-0307-1 108-0307-001 B Yellow 15 16AWG 
530-108-0308-1 108-0308-001 B Brown 15 16AWG 
530-108-0310-1 108-0310-001 B Blue 15 16AWG 
530-108-0312-1 108-0312-001 B Violet 15 16AWG 
530-108-0313-1 108-0313-001 B Gray 15 16AWG 
Insulated Hex Body Solder Long Handle
530-108-0752-2 108-0752-002 C Red 15 16AWG 
530-108-0752-1 108-0752-001 C Black 15 16AWG 
Insulated Round Body Solder Stud
530-108-1723-101 108-1723-101 D Black 15 16AWG 
530-108-1722-101 108-1722-101 D Red 15 16AWG 
530-108-1722-103 108-1722-103 D Red 15 16AWG 
Insulated Stacking Single
530-108-1082-1 108-1082-001 E Red 15 16AWG 
530-108-1083-1 108-1083-001 E Black 15 16AWG 
530-108-1081-1 108-1081-001 E White 15 16AWG 
Dual-Insulated Stacking Set Screw
530-108-0252-1 108-0252-001 F Red 15 14AWG 
530-108-0253-1 108-0253-001 F Black 15 14AWG 
Uninsulated Panel .375" Threaded Stud
530-108-0750-1 108-0750-001 G Nickel 15 14AWG 
Uninsulated Panel Screw Type
530-108-0753-1 108-0753-001 H Silver 15 14AWG 
Miniature-Insulated Solder Type
530-108-1002-1 108-1002-001 I Red 10 18AWG 
530-108-1003-1 108-1003-001 I Black 10 18AWG 
BANANA JACKS
For quantities greater than listed, call for quote.
MOUSER
STOCK NO.
Johnson
Components 
Part No.
Fig. Color Amps Max.Wire
Price Each
1 10 25 100 500 1000
Insulated Solder Terminal
530-108-0902-1 108-0902-001 J Red 15 16AWG 
530-108-0903-1 108-0903-001 J Black 15 16AWG 
530-108-0901-1 108-0901-001 J White 15 16AWG 
530-1080904-1 108-0904-001 J Green 15 16AWG 
530-108-0906-1 108-0906-001 J Orange 15 16AWG 
530-108-0907-1 108-0907-001 J Yellow 15 16AWG 
530-108-0908-1 108-0908-001 J Brown 15 16AWG 
530-108-0910-1 108-0910-001 J Blue 15 16AWG 
530-108-0912-1 108-0912-001 J Violet 15 16AWG 
530-108-0913-1 108-0913-001 J Grey 15 16AWG 
Uninsulated Solder Terminal
530-108-0740-1 108-0740-001 K Nickel 15 12AWG 
Miniature-Insulated Rib-Loc® Turret Terminal
530-108-1102-1 108-1102-001 L Red 10 - - - 
Insulated Rib-Loc® Solder Terminal
530-108-2301-1 108-2301-801 M White 15 16AWG 
530-108-2302-1 108-2302-801 M Red 15 16AWG 
BINDING POSTS
For quantities greater than listed, call for quote.
MOUSER
STOCK NO.
Johnson
Components 
Part No.
Fig. Color Amps PanelThickness
Price Each
1 10 25 100 500 1000
Insulated Standard
530-111-0102-1 111-0102-001 N Red 15 up to .281 
530-111-0103-1 111-0103-001 N Black 15 up to .281 
530-111-0101-1 111-0101-001 N White 15 up to .281 
530-111-0104-1 111-0104-001 N Green 15 up to .281 
530-111-0107-1 111-0107-001 N Yellow 15 up to .281 
530-111-0110-1 111-0110-001 N Blue 15 up to .281 
Uninsulated Grounded Type
530-111-2223-001 111-2223-001 O Nickel 15 up to .281 
Insulated Grounded Type
530-111-0702-001 111-0702-001 P Red 15 up to .313 
530-111-0703-001 111-0703-001 P Black 15 up to .313 
DIMENSIONS: in.
A B
C D
E F
G H
I J
K L
M N
O P
mouser.com/johnson
© Copyright 2015 Mouser Electronics© Copyright 2015 Mouser Electronics
asia.pacific@mouser.comFor current pricing,visit mouser.com 
Accumulator
Page 93
www.multi-contact.com 191
®
Weiteres Buchsenzubehör
Schutzdeckel
Further Socket Accessories
Protective Caps
Accessoires divers pour douilles
Couvercles de protection
SCHUDE-LB SCHUDE-SLB
SCHUDE-SLB
SEB4...
SLB4...
XE..-1R(R)
Schutzdeckel zum Verschluss von Buchsen
im unbeschalteten Zustand.
Protective cap to cover-up unplugged,
unused sockets.
Couvercle de protection pour obturer
des douilles à l’état non connecté.
Typ
Type
Type
Best.-Nr.
Order No.
N° de Cde
Geeignet für Buchsentypen
Suitable for socket types
Douilles correspondantes
Farbe
Colour
Couleur
SCHUDE-SLB 23.5140-33 SEB4..., SLB4..., XE..-1R(R)
MB
SCHUKA-SLB
SEB4...
SLB4...
XE..-1R(R)
Schutzkappe als Schutz vor Berührung des
rückseitigen Buchsenanschlusses.
Safety hood, designed for a touch-protected
cover-up of connecting parts of sockets.
Capuchon de protection pour la protection au
toucher de la partie raccordement des douilles.
Typ
Type
Type
Best.-Nr.
Order No.
N° de Cde
Geeignet für Buchsentypen
Suitable for socket types
Douilles correspondantes
Farbe
Colour
Couleur
SCHUKA-SLB 23.5142-33 SEB4..., SLB4..., XE..-1R(R)
MB
XAS-1R ID-SAB4-G H-ESD-ID/S4-S
ID-SAB4-GXAS-1RH-ESD-ID/S4-S
Distanzhülsen zum erhöhten Aufbau von Buch-
sen und Dosen.
Spacer sleeves to increase the height of the
mounting position of sockets and receptacles.
Entretoises pour le montage en saillie des
douilles et embases.
Typ
Type
Type
Best.-Nr.
Order No.
N° de Cde
Geeignet für Buchsentypen
Suitable for socket types
Douilles correspondantes
*Farben
*Colours
*Couleurs
XAS-1R 66.9151-* SEB4..., SLB4..., XE..-1R(R)
Q1Q2Q3Q4Q5
Q6
ID-SAB4-G 23.5039-* SAB4-G...
Q1Q2Q3Q4Q5
Q6Q7Q8L9
H-ESD-ID/S4-S 24.5184-24 ESD-ID/S4-S, SLB4-T/N-S
Q4
Schutzkappen Safety Hoods Capuchons de protection
Distanzhülsen Spacer Sleeves Entretoises
Accumulator
Page 94
AMP20M1HD-A
 High usable energy over a wide state of charge (SOC) range
 and very low cost per Watt-hour
 Excellent abuse tolerance and superior calendar and cycle life from
 A123’s patented Nanophosphate® lithium ion chemistry 
 High power with over 2,400 W/kg and 4,500 W/L
AMP20 Cell Speci�cations
Cell Dimensions (mm) 7.25 x 160 x 227
Cell Weight (g) 496
Cell Capacity (minimum, Ah) 19.6
Energy Content (nominal, Wh) 65
Discharge Power (nominal, W) 1200
Voltage (nominal, V) 3.3
2400
131
Energy Density (nominal, Wh/L) 247
Operating Temperature -30°C to 55°C
Storage Temperature -40°C to 60°C
Test Result
Nail Penetration Pass – EUCAR 3
Overcharge Pass – EUCAR 3
Over-discharge Pass – EUCAR 3
Thermal Stability Pass – EUCAR 4
External Short Pass – EUCAR 3
Crush Pass – EUCAR 3
APPLICATIONS
Utility-scale Storage
©2011 A123 Systems, Inc. All rights reserved.
Nanophosphate® Lithium Ion Prismatic Pouch Cell 
www.a123systems.com
PHEV and EV Passenger Vehicles PHEV and EV Commercial Vehicles
Speci�c Power (nominal, W/kg)
Speci�c Energy (nominal, Wh/kg)
MD100105-01
KEY FEATURES AND BENEFITS
Abuse Test
Accumulator
A.1.3 A123 Cells
Page 95
©2011 A123 Systems, Inc. All rights reserved.
CORPORATE HEADQUARTERS
A123 Systems Inc.
321 Arsenal St.
Watertown, MA 02472
(617) 778-5700
 
 
 
A123 Systems makes no warranty explicit or implied with this datasheet. Contents subject to change without notice.
POWER
CYCLE LIFE
 
10s Pulse Power Capability vs State of Charge at 23°C, Using FreedomCAR HPPC
Vmax = 3.8 V, Vmin = 1.6 V
Capacity vs Cycles
100% Depth of Discharge (DOD), +1C/-2C, 23°C
% 
In
iti
al
 C
ap
ac
ity
MD100105-01
Cycles
100%
90%
80%
70% 
60%
50%
0 500 1000 1500 2000 2500
% State of Charge (SOC)
www.a123systems.com
3000 3500
Nanophosphate® Lithium Ion Prismatic Pouch Cell
AMP20M1HD-ADischarge Power (W)
Di
sc
ha
rg
e P
ow
er
 (W
)
10s Discharge Pulse Capability
10s Regen Pulse Power Capability
Re
ge
n 
Po
we
r (
W
)
1600
1400
1200
1000
600
800
200
400
0
1440
1280
1120
960
480
640
160
320
0
800
0% 10% 50% 70% 80% 90% 20% 30% 60% 100% 40%
10s Discharge Pulse Capability
10s Regen Pulse Power Capability
Accumulator
Page 96
User’s Manual for Advanced Axial Flux SynchronousMotors and Generators 
1 
 
EMRAX 208 Technical Data Table (dynamometer test data) 
Technical data 
Type 
EMRAX 208 
High Voltage 
EMRAX 208 
Medium Voltage 
EMRAX 208 
 Low Voltage 
Air cooled = AC 
Liquid cooled = LC 
Combined cooled = Air + Liquid cooled = CC 
AC LC CC AC LC CC AC LC CC 
Ingress protection IP21 IP65 IP21 IP21 IP65 IP21 IP21 IP65 IP21 
Cooling medium specification 
(Air Flow = AF; Inlet Water/glycol Flow = 
WF; Ambient Air = AA) 
If inlet WF temperature and/or AA 
temperature are lower, then continuous 
power is higher. 
AF=20m/s; 
AA=25°C 
WF=8l/min 
at 50°C; 
AA=25°C 
WF=8l/min 
at 50°C; 
AA=25°C 
AF=20m/s; 
AA=25°C 
WF=8l/min 
at 50°C; 
AA=25°C 
WF=8l/min 
at 50°C; 
AA=25°C 
AF=20m/s; 
AA=25°C 
WF=8l/min 
at 50°C; 
AA=25°C 
WF=8l/min 
at 50°C; 
AA=25°C 
Weight [kg] 9,1 9,4 9,3 9,1 9,4 9,3 9,1 9,4 9,3 
Diameter ø / width [mm] 208 / 85 
Maximal battery voltage [Vdc] and full 
load/no load RPM 
470 Vdc (5170/7050 RPM) 320 Vdc (5760/7040 RPM) 125 Vdc (6250/7250 RPM) 
Peak motor power at max RPM (few min 
at cold start / few seconds at hot start) 
[kW] 
80 
Continuous motor power (at 3000-5000 
RPM) depends on the motor RPM [kW] 
20 - 32 20 - 32 25 - 40 20 - 32 20 - 32 25 - 40 20 - 32 20 - 32 25 - 40 
Maximal rotation speed [RPM] 6000 (7000 peak for a few seconds) 
Maximal motor current (for 2 min if cooled 
as described in Manual) [Arms] 
200 320 800 
Continuous motor current [Arms] 100 160 400 
Maximal peak motor torque [Nm] 150 
Continuous motor torque [Nm] 80 
Torque / motor current [Nm/1Aph rms] 0,83 0,54 0,20 
Maximal temperature of the copper 
windings in the stator and max. 
temperature of the magnets [°C] 
120 
Motor efficiency [%] 92-98% 
Internal phase resistance at 25 °C [mΩ] 12,0 5,7 0,8 
Input phase wire cross-section [mm2] 10,2 15,2 38 
Wire connection star 
Induction Ld/Lq [µH] 125/130 52/56 7,2/7,5 
Controller / motor signal sine wave 
AC voltage between two phases 
[Vrms/1RPM] 
0,0487 0,0319 0,0117 
Specific idle speed (no load RPM) 
[RPM/1Vdc] 
15 22 58 
Specific load speed (depends on the 
controller settings) [RPM/1Vdc] 
11 – 15 18 – 22 50 – 58 
Magnetic field weakening (for higher RPM 
at the same power and lower torque) [%] 
up to 100 
Magnetic flux – axial [Vs] 0,0393 0,0257 0,095 
Temperature sensor in the motor kty 81/210 
Number of pole pairs 10 
Rotor Inertia (mass dia=160mm, m=4,0kg) 
[kg*cm²] 
256 
Bearings (front:back) - SKF/FAG 
6206:6206 (for radial forces) or 6206:7206 (for axial-radial forces; for pull mode; e.g. for air propeller) or 6206:3206 (for 
axial-radial forces; for pull-push mode; »O« orientation, α=25°); other bearings are possible (exceptionally) 
 
 
Accumulator
A.1.4 EmraxMotor
Page 97
User’s Manual for Advanced Axial Flux Synchronous Motors and Generators 
2 
 
Graphs valid for EMRAX High Voltage Combined Cooled (CC) motor type: 
 
 
 
 
 
 
Accumulator
Page 98
User’s Manual for Advanced Axial Flux Synchronous Motors and Generators 
3 
 
 
 
 
 
 
 
 
Graphs of the EMRAX 208 Medium and Low voltage motor type: 
Graphs of EMRAX 208 Low Voltage and EMRAX 208 Medium Voltage are similar to graphs of EMRAX 208 High 
Voltage. The only differences are the DC voltage and motor current. These two parameters can be read from 
the Technical data table for the EMRAX 208 Low and Medium Voltage motor. 
Low Voltage motor needs 4 x higher motor current and 4 x lower DC voltage for the same power/torque and 
RPM, compared to EMRAX 208 High Voltage motor. 
Medium Voltage motor needs 1.52 x higher motor current and 1/3 lower DC voltage for the same 
power/torque and RPM, compared to EMRAX 208 High Voltage motor. 
 
Graphs of the EMRAX 208 Liquid cooled (LC) and EMRAX 208 Air Cooled (CC): 
Continuous power of the liquid cooled or air cooled motor is 20% lower than continuous power of the 
combined cooled motor. The peak power is the same. Data is presented in the Technical Data Table. 
Accumulator
Page 99
Accumulator
A.2 Code
A.2.1 Microcontroller Code:
#include <SPI.h>
#include <SD.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#define ONE_WIRE_BUS 5
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);
const int chipSelect = 4;
long durationTest;
const int relay = 2;
const int GLED = 6;
const int RLED = 7;
const int ampSensePin = A6;
const int battVoltPin = A4;
int ampSensePinADCVAL;
int battVoltPinADCVAL;
long startTime;
long currentTime;
long finishTime;
long pulseHighTime;
long pulseTotalTime;
String testType;
String dataString;
float criticalVoltage = 2.0; //3.0 for WS;2.0 for AMP
int emergency = 1;
int state = 1;
void setup()
{
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only
}
sensors.begin();
pinMode(GLED, OUTPUT);
pinMode(RLED, OUTPUT);
pinMode(relay, OUTPUT);
digitalWrite(relay, LOW);
delay(1000);
for (int i=0;i<5;i++){
digitalWrite(7, HIGH);
delay(1000);
Page 100
Accumulator
digitalWrite(7, LOW);
delay(1000);
}
digitalWrite(GLED, LOW);
digitalWrite(RLED, LOW);
}
void loop() {
if (Serial.available() > 0){
emergency = Serial.parseInt();
//Serial.println(emergency);
}
if (emergency == 1){
digitalWrite(relay, LOW);
digitalWrite(RLED, HIGH);
digitalWrite(GLED, LOW);
delay(10000);
state = 0;
}
else if (emergency == 0){
// File dataFile = SD.open("AMP2Drain.txt", FILE_WRITE);
state = 1;
digitalWrite(relay, HIGH);
digitalWrite(GLED, HIGH);
digitalWrite(RLED, LOW);
float battVolt = float(analogRead(battVoltPin)) / 1023.0 * 5.0;
float ampSense = (analogRead(ampSensePin)/1023.0*5) / 0.025;
sensors.requestTemperatures();
float temp = sensors.getTempCByIndex(0);
while (battVolt < criticalVoltage || state == 0){
digitalWrite(relay, LOW);
digitalWrite(RLED, HIGH);
digitalWrite(GLED, LOW);
Serial.println("ERROR - BATT VOLTAGE TOO LOW -10 SEC DELAY");
Serial.println(battVolt);
delay(10000);
battVolt = float(analogRead(battVoltPin)) / 1023.0 * 5.0;
state = 0;
}
dataString = String((millis())) + "; " + String(ampSense) + "; "
+ String(battVolt) + "; " + String(temp) + ";";
Serial.println(dataString);
delay(3000);
}
Page 101
Accumulator
A.2.2 Raspberry Pi Code
import matplotlib.pyplot as plt
import time
import random
import serial
import csv
import warnings
import matplotlib.cbook
warnings.filterwarnings("ignore",category=matplotlib.cbook.mplDeprecation)
ser = serial.Serial(’/dev/ttyUSB3’,9600)
ser.baudrate = 9600
y1 = []
y2 = []
my_time = []
voltage = []
temp = []
voltage_read = 0;
INITIAL_X_AXIS_LEN = 50
plt.show()
ax1 = plt.gca()
ax1.set_xlim(0, INITIAL_X_AXIS_LEN)
ax1.set_ylim(0, 10)
ax1.set_ylabel(’voltage’, color="b")
line1, = ax1.plot(my_time, voltage, ’b-’)
ax2 = ax1.twinx()
ax2.set_xlim(0, INITIAL_X_AXIS_LEN)
ax2.set_ylim(0, 500)
ax2.set_ylabel(’temp’, color="g")
line2, = ax2.plot(my_time, temp, ’g-’)
#sample
t = 0
while True:
read_serial = ser.readline()
data = read_serial.split()
time = float(data[0])
amp = float(data[1])
volt = float(data[2])
#measuring voltage from ADC
voltage_read = volt/1023.0 * 5.0
voltage_read = round(voltage_read, 3)
#measuring amp from ADC
Page 102
Accumulator
amp_read = (amp/1023.0 * 5.0) /0.025
amp_read = round(amp_read, 3)
#converting time to seconds
time_sec = time / 1000.0
time_sec = round(time_sec, 1)
y1.append(voltage_read)
y2.append(amp_read)
if (y1[t] > 2.00):
# get next data
my_time.append(t)
voltage.append(y1[t])
temp.append(y2[t])
with open(’test_result.csv’, ’a’, newline = ’’) as csvfile:
filewriter = csv.writer(csvfile, delimiter=’ ’, quotechar = ’|’, quoting=csv.QUOTE_MINIMAL)
filewriter.writerow([time_sec, t, y1[t], y2[t]])
t += 1
line1.set_xdata(my_time)
line1.set_ydata(voltage)
line2.set_xdata(my_time)
line2.set_ydata(temp)
if (len(my_time) > INITIAL_X_AXIS_LEN):
ax1.set_xlim(0, len(my_time))
plt.gcf().canvas.flush_events()
plt.show(block=False)
#plt.pause(1e-17)
#plt.show()
#time.sleep(0.25)
else:
plt.show()
# add thisif you don’t want the window to disappear at the end
plt.show()
Page 103
Accumulator
A.3 Bill of Materials
Figure 72: 2017 Bill of Materials - Part 1
Figure 73: 2017 Bill of Materials - Part 2
Page 104
	Introduction
	FSAE Competition
	Melbourne University Racing - Electric
	Tractive System Overview
	Project Aims
	Team Accomplishments
	Literature Review
	Battery Pack Configuration
	Cabling
	Cell Selection
	Lithium Ion Cells
	Cell Components
	Cell Enclosure
	Lithium Ion Chemistries
	Lithium Iron Phosphate (LiFePO4)
	A123’s AMP20M1HD-A
	Safety
	Lithium Ion Battery Hazards
	Safety Incidents
	Emergency Procedures
	Hot Cell
	Vented Cell
	Cell/Battery Disposal
	First Aid Procedures
	Fire Fighting Measures
	Personal Protective Equipment:
	Risk Analysis
	Single Cell Testing
	High(Hazardous) Voltage
	Standard Operating Procedures
	Cell Testing
	Cell Charging
	Module/Accumulator Assembly & Testing
	Swapping Damaged Cells
	Accumulator Removal and Charging
	Low Voltage Wire Crimping
	Design Development
	Design Constraints
	Cell Segmentation
	Initial Design
	Cooling Plate/Fins
	Cell Interconnection
	Prototyping
	Cabling
	Handling
	Low Voltage Battery
	Accumulator Isolation Relay
	Contactor
	Cabling
	Tractive System Active Light
	Container/Housing
	Container Design
	Thermal Analysis
	Extra Safety Measures
	Tractive System Wiring
	High Voltage Disconnect
	Tractive System Measuring Points
	Tractive System Master Switch
	Charge Cart
	FSAE Rule Requirements
	Cart Dimensions
	Material Selection
	Wheel Selection
	Accumulator Indicator Light
	Design Considerations
	Schematics and Wiring
	HV Section Schematic Analysis
	LV Section Schematic Analysis
	Safety Extension
	Component Placement in the Car
	Precharge Circuit
	Overview
	Design Consideration
	Component Placement in the Car
	Discharge Circuit
	Design Consideration
	Component Placement in the Car
	Design Implementation and Testing
	Manufacturing
	Transforming Design for Manufacture Process
	Laser Cut Components
	Water Jet Components
	CNC Machined Components
	3D Printed Components
	Components using hand tools
	Assembly
	Segment Assembly
	Low Voltage Battery Assembly
	Container Assembly
	BMS Implementation to the segment
	Further implementation
	Cell Testing
	Individual Cell Acceptance Testing
	Load Bank 2016
	Prototype and Model Development
	Procedure and Technicality
	Interfaces
	Safety Consideration
	Load Bank 2017
	Design and Model Development
	Internal Circuitry and Safety
	Testing Data and Analysis
	Battery Safety Charging System (BSCS)
	Introduction
	Risks and Safety 
	Charging Characteristic and Safety
	Design and Final Product
	Conclusion
	Bibliography
	Appendix
	Datasheets
	High Voltage Disconnect
	Tractive System Measuring Points
	A123 Cells
	Emrax Motor
	Code
	Microcontroller Code:
	Raspberry Pi Code
	Bill of Materials