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
 &
 Safety