Lithium-Ion Battery Standards 9781630818869

Table of contents :
Cover
Half Title
Lithium-Ion Battery Standards
Copyright
Contents
Preface
1. Lithium-Ion Battery Introduction
1.1 Introduction
1.2 Terminology in Battery Systems
1.3 Lithium-Ion Battery System
1.3.1 Form Factor and Battery Cell Identification
1.3.2 Output Voltage
1.3.3 Implementation
1.4 Lithium-Ion Battery Cell Construction
1.4.1 Battery Cell Packaging Materials
1.4.2 Battery Cell Form Factors
1.4.2.1 Cylindrical Battery Pack Cells
1.4.2.2 Pouch and Prismatic Battery Pack Cells
1.4.2.3 Button or Coin Lithium-Ion Battery Pack Cells
1.4.3 The Components Used in a Lithium-Ion Battery Pack Cell Electrode Assembly
1.4.3.1 Positive Electrode
1.4.3.2 Negative Electrode
1.4.3.3 Separator
1.4.3.4 Electrolyte
1.4.4 The Electrode Assembly
1.4.5 Graphite-Based System Operation
1.5 Lithium-Ion Battery Cell Performance Characteristics by Definition
References
2. Battery Systems Architectures
2.1 The Battery Pack System
2.1.1 The Lithium-Ion Cell
2.1.1.1 The Lithium-Ion Battery Pack
2.1.2 The Charger
2.1.3 The Discharger
2.1.4 The Power Source
2.2 Lithium-Ion Battery System Subsystems
2.2.1 Battery System Power Sources
2.2.1.1 AC Power Converters
2.2.1.2 DC Power Converters
2.2.1.3 AC and DC Power Converter
2.2.2 Battery Pack Charger Architectures
2.2.2.1 The Battery Pack Charger Integrated into the Power Converter
2.2.2.2 Battery Pack Charger Integrated into the Product
2.2.2.3 Battery Pack Charger Integrated into the Battery Pack Enclosure
2.2.3 Battery Pack Battery Management Unit Circuit Architectures
2.2.3.1 Single-Cell Battery Pack BMU
2.2.3.2 Multiseries Cell Battery Pack BMU
2.2.4 Battery Pack Architectures
2.2.4.1 Series Cell Battery Pack Architectures
2.2.4.2 Series Cell Battery Pack Architecture
2.2.4.3 Battery Module Architecture
2.2.5 The Battery Pack Cell
2.2.5.1 Battery Pack System Architectures
2.2.6 The Exchangeable Battery Pack Architecture
2.2.7 User-Replaceable Battery Pack and Internal Device Battery Pack Charger
2.2.8 Nonuser-Replaceable Battery Pack and Internal Device Battery Pack Charger
2.2.9 Portable Power Source
2.2.10 The Modular Battery
2.2.11 Nonmodular Universal Serial Bus Storage System Architecture
2.2.12 Modular and Nonmodular Electrical Storage System Architecture
2.3 The Battery Pack Cell Datasheet and the Battery Pack Cell Specification
References
3. Lithium-Ion Battery Safety Considerations
3.1 Introduction
3.2 Product or System Reliability Versus Safety
3.3 Lithium-Ion Battery Cell Failure Causes and Modes
3.3.1 Thermal Runaway
3.3.2 Internal Short Circuit
3.3.3 Lithium Plating
3.3.4 Cell Failure Mechanisms
3.3.4.1 Cell Design
3.3.4.2 Manufacturing
3.3.4.3 Mechanical Stress
3.3.4.4 Electrical Over Stress
3.3.4.4.1 Charge Voltage Over Stress
3.3.4.4.2 Charge Current Over Stress
3.3.4.5 Thermal Stress
3.3.4.6 Charge Algorithm
3.3.4.7 Discharge Algorithm
3.3.5 Battery Pack Failure Modes
3.3.5.1 Organic Carbonization Resistive Fault
3.3.5.2 Protection Devices
3.3.6 Electrical and Electronic Component Failures
3.3.6.1 Surface Mount Chip (MLC) Ceramic Capacitors
3.3.6.2 Metal Oxide Varistors
3.3.6.3 Electrolytic Capacitors
3.3.6.4 Electromechanical Relays
3.3.6.5 Field Effect Transistors
3.3.6.6 Solid State Relays
3.3.7 High-Voltage Isolation
3.3.8 Environment and Environmental Conditions to Consider
3.3.9 Environmental Compatibility
3.3.10 Critical and Unique Requirement Considerations
3.3.11 Recyclability
3.3.12 Storage
References
4. The Law and Battery Product Safety
4.1 Introduction
4.2 The Evolution of Product Safety
4.2.1 Product Safety and Product Battery System Regulations
4.2.2 Product and Product Battery System Safety Control Management
4.2.3 Product and Product Battery System Safety Certifications
4.3 The Law and Product and Product Battery System Safety Compliance
4.3.1 Product and Product Battery System Liability
4.3.2 Historical Background
4.3.3 Types of Battery Product and Product Battery System Defects
4.4 Product and Product Battery System Compliance
4.4.1 Why is Product and Product Battery System Compliance Necessary?
4.4.1.1 Engineering and New Product and Product Battery System Management
4.4.1.2 Legal
4.4.1.3 Sales and Marketing
4.4.1.4 Customer Support
4.4.1.5 Quality
4.4.1.6 Operations and Logistics
4.4.1.7 Distribution
4.4.2 Risks of Nonconformance of the Product and Product Battery System
References
5. Regulatory Requirements and Safety Standards
5.1 Introduction
5.2 International and Foreign Regulatory Organizations
5.3 International Battery Standards
5.4 Regulatory Organizations in the United States
5.5 Battery Standards Organizations Located in the United States
5.5.1 Lithium-Ion Battery Standards in the United States
5.5.2 Description of Selected Standards Used in the United States
5.5.2.1 UN/DOT 38.3 Transportation and Testing of Lithium-Ion Batteries and Cells
5.5.2.2 International Electrotechnical Commission
5.5.2.2.1 IEC 62281
5.5.2.2.2 IEC 62619
5.5.2.2.3 IEC 62660
5.5.2.2.4 IEC 61960
5.5.2.2.5 IEC 62133-2:2017
5.5.2.2.6 IEC 61959:2004
5.5.2.3 International Organization for Standards
5.5.2.3.1 ISO 12405
5.5.2.4 Underwriters Laboratory Standards
5.5.2.4.1 UL 1642
5.5.2.4.2 UL 2054
5.5.2.4.3 UL 62133-2
5.5.2.4.4 UL1973
5.5.2.4.5 UL 2271
5.5.2.4.6 UL 2272
5.5.2.4.7 UL 2580
5.5.2.4.8 UL 1974, 1st Edition
5.5.2.4.9 UL 1998
5.5.2.4.10 UL 9540A, 4th Edition
5.5.2.5 Society for Automotive Engineers
5.5.2.5.1 SAE J1772
5.5.2.5.2 SAE J2464
5.5.2.6 Institute for Electrical and Electronic Engineers
5.5.2.6.1 IEEE 1625 – 2008
5.5.2.6.2 IEEE 1725–2021
5.5.2.6.3 IEEE P2686 Recommended Practice for Battery Management Systems in Energy Storage Applications
5.5.3 Procedural Test Standards
5.5.3.1 ISO 26262
5.5.3.2 SAE J3220_202301
5.5.3.3 SAE J3235_202303
5.5.3.4 LV 123
5.5.3.5 FreedomCAR
5.5.3.6 USABC
5.5.4 Codes and Authority Having Jurisdictions
References
6. Portable Consumer Product Battery System Standards
6.1 Introduction
6.2 Power Source
6.2.1 AC Power Converters
6.2.2 Variations
6.2.3 Relevant Standards
6.2.4 Safety Compliance
6.2.4.1 AC Mains Power Source
6.2.4.2 DC-DC Converters
6.3 Charger
6.4 Relevant Standards
6.5 Safety Compliance
6.6 The Battery Pack
6.7 Single-Series Cell Battery Pack Architecture
6.8 Series Cell and Series-Parallel Cell Lithium-Ion Battery Pack Architectures
6.9 Relevant Standards
6.10 Battery Cell
6.11 Relevant Standards
6.12 The Product Lithium-Ion Battery System
6.13 Lithium-Ion Battery System Architectures
6.13.1 Relevant Standards
6.13.2 Other Relevant Standards
7. Medical Product Battery System Standards
7.1 Introduction
7.1.1 Relevant Standards
7.2 Power Source
7.2.1 AC Power Converters
7.2.2 Relevant Standards
7.2.2.1 AC Mains Connection
7.3 Battery System Battery Charger Architectures
7.3.1 Relevant Standards
7.4 The Battery Pack
7.4.1 Typical Battery Architectures
7.4.1.1 Series Cell Battery Architecture
7.4.1.2 Series Cell Battery Architecture
7.4.2 Relevant Standards
7.5 Battery Cell
7.5.1 Relevant Standards
7.6 The Integrated Battery System
7.6.1 Relevant Standards
7.6.2 Implementation of the Standards
7.7 Other Relevant Standards
7.7.1.1 ANSI C18 Series
7.7.1.2 UL 1642 Lithium Batteries
7.7.1.3 UL 2054 Household and Commercial Batteries
7.7.1.4 United Nations Manual of Tests and Criteria, Section 38.3
8. E-Mobility Battery System Standards
8.1 Introduction
8.2 Battery System Power Sources
8.2.1 Relevant Standards
8.2.1.1 Implementation of the Standards
8.3 The Battery Charger Architectures
8.3.1 Relevant Standards
8.3.2 Implementation of the Standards
8.4 The Battery Pack
8.4.1 The Battery Module
8.4.2 Relevant Standards
8.5 The Battery Cell
8.6 The Battery System
8.6.1 Relevant Standards
8.7 Summary of E-Mobility Standards and Product Categories
8.7.1.1 ANSI C18 Series
8.7.1.2 UL 1642 Lithium Batteries
8.7.1.3 UL 2054 Household and Commercial Batteries
8.7.1.4 United Nations Manual of Tests and Criteria, Section 38.3
9. Automotive Battery System Standards
9.1 Introduction
9.2 Chargers
9.2.1 Level 1 Charging
9.2.2 Level 2 Charging
9.2.3 Level 3 Charging
9.2.4 Relevant Standards
9.3 The Vehicle Battery
9.3.1 Relevant Standards
9.4 Battery Cell Standards
9.4.1 Relevant Standards
9.5 Other Relevant Standards
9.5.1 ANSI C18 Series
9.5.2 UL 1642 Lithium Batteries
9.5.3 UN/DOT 38.3 Transportation Testing 
9.5.4 UL 2054 Household and Commercial Batteries
9.6 Additional Product Categories
9.6.1 E-Motorcycles
9.6.2 E-Bike (Recreational Use)
9.6.3 Heavy-Duty Electric Vehicles
9.6.4 Electric Forklifts
9.6.5 Electric Autonomous Cleaners
9.6.6 Electric Mining Vehicles
9.6.7 Electric All-Terrain Vehicles and Utility Terrain Vehicles
10. Toy Battery System Standards
10.1 Introduction
10.2 Battery System Power Sources
10.2.1 Power Converters
10.2.2 Relevant Standards
10.3 Battery System Charger
10.3.1 Relevant Standards
10.4 The Battery Pack
10.4.1 Single-Series Cell Battery Architecture
10.4.2 Multiseries Cell Battery Architecture
10.4.3 Relevant Standards
10.4.4 Battery Standards
10.5 Battery Cell Standards
10.6 The Battery-Powered Product
10.6.1 Relevant Standards
10.6.1.1 ANSI C18 Series
10.6.1.2 UL 1642 Lithium Batteries
10.6.1.3 UL 2054 Household and Commercial Batteries
10.6.1.4 United Nations Manual of Tests and Criteria, Section 38.3
11. Cellular Device Battery System Standards
11.1 Introduction
11.2 Battery System Power Sources
11.2.1 Relevant Standards
11.3 Battery System Battery Charger Architectures
11.3.1 Relevant Standards
11.3.2 The Battery Pack
11.3.3 Battery Architectures
11.3.3.1 Single Series Cell Battery Architecture
11.3.3.2 Multiseries Cell Battery Architecture
11.3.4 Relevant Standards
11.4 Battery Cell Standards
11.5 The Integrated Battery System
11.5.1 Relevant Standards
11.5.1.1 ANSI C18 Series
11.5.1.2 UL 1642 Lithium Batteries
11.5.1.3 UL 2054 Household and Commercial Batteries
11.5.1.4 United Nations Manual of Tests and Criteria, Section 38.3
11.5.2 Relevant Product Categories and Safety Standards
11.5.2.1 Tablets
11.5.2.2 Remote Monitoring Devices
12. Clothing Battery System Standards
12.1 Introduction
12.2 Battery System Power Sources
12.2.1 AC Power Converters
12.2.2 Relevant Standards
12.3 Battery System Battery Charger Architectures
12.3.1 Relevant Standards
12.4 The Battery Pack
12.4.1 Battery Pack Architectures
12.4.1.1 Single-Series Cell Battery Pack Architecture
12.4.1.2 Multiseries Cell Battery Pack Architecture
12.4.2 Relevant Standards
12.5 The Battery Cell
12.5.1 Relevant Standards
12.6 The Product-Integrated Battery System
12.6.1 Relevant Standards
12.6.1.1 Bracelets (Fitness Trackers)
12.6.1.2 Glasses (Video Capture and Monitor)
12.6.1.3 Rings (Heart Monitor)
12.6.1.4 Smart Watch (May Include Mobile Phone Features)
12.6.1.5 Gloves
12.6.1.6 Jackets
12.6.1.7 Socks
12.6.1.8 Footwear
12.6.2 Other Relevant Standards
12.6.2.1 ANSI C18 Series
12.6.2.2 UL 1642 Lithium Batteries
12.6.2.3 UL 2054 Household and Commercial Batteries
12.6.2.4 United Nations Manual of Tests and Criteria, Section 38.3
13. Electrical Storage Battery Standards
13.1 Introduction
13.2 Portable Power Pack
13.2.1 The Battery Pack System Power Source
13.2.2 The Battery Pack Charger Architectures
13.2.3 The Lithium-Ion Battery Pack
13.2.3.1 Single-Series Cell Battery Pack Architecture
13.2.3.2 Multiseries Cell Battery Pack Architecture
13.2.4 The Battery Pack Cell
13.2.5 The Portable Power Pack System Architecture
13.3 6V/12V Lithium-ion Batteries
13.3.1 The Battery System Power Source
13.3.2 The Battery Pack Charger Architectures
13.3.3 The Battery Pack
13.3.4 The Battery Cell
13.3.5 The Battery System Architecture
13.3.6 Relevant Standard
13.4 Home Electrical Storage Systems (Home Backup Power)
13.4.1 The Battery System Power Source
13.4.2 The Battery Pack Charger Architectures
13.4.3 The Lithium-Ion Battery
13.4.4 The Battery Cell
13.4.5 The Battery System Architecture
13.4.6 Nonmodular Battery System Architectures
13.4.7 Relevant Standard
13.5 Uninterrupted Power Supply Systems
13.5.1 Relevant Standard
13.6 Grid Battery Electric Storage Systems
13.6.1 The Battery System Power Source
13.6.2 The Battery Pack Charger Architectures
13.6.3 The Battery Pack Architectures
13.6.4 The Battery Cell
13.6.5 The Battery System Architecture
13.6.6 Relevant Standards
Reference
14. Aviation Battery System Standards
14.1 Introduction
14.2 Battery System Power Sources
14.2.1 Relevant Standards
14.3 Battery System Charger Architectures
14.4 The Battery Pack
14.4.1 Relevant Standards
14.5 The Battery Cell
14.6 The Integrated Battery System
14.7 Product Category Specific Relevant Standards
14.7.1 Unmanned Commercial Drones
14.7.2 Passenger Winged Aircraft
14.7.3 Rideshare Taxis
15. Lithium-Ion Battery Shipping in the United States
15.1 Introduction
15.2 Local Shipping in the United States and International Shipping
15.3 Shipping Testing Requirements
15.4 Lithium-Ion Battery Shipping Descriptions and Testing Requirements
15.5 Shipping Prototype Batteries
15.6 Damaged Batteries
15.7 Does Battery Size Matter?
15.8 PHMSA Document Shipping Guidelines
15.9 International Shipping
15.10 Private Shippers in the United States
15.11 Noncompliance
References
Appendix: The Cell Datasheet
Glossary of Terminology Used in Battery Systems
About the Authors
Index
Artech House Power Engineering Library Series

Citation preview

L I T H I U M - I O N B AT T E R Y S TA N D A R D S

For a complete listing of titles in the Artech House Power Engineering Library, turn to the back of this book.

L I T H I U M - I O N B AT T E R Y S TA N D A R D S Jan Swart Jody Leber

Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the U.S. Library of Congress. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. Cover design by Joi Garron

ISBN 13: 978-1-63081-886-9

© 2025 Artech House 685 Canton Street Norwood, MA 02062

All rights reserved. Printed and bound in the United States of America. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the publisher. All terms mentioned in this book that are known to be trademarks or service marks have been appropriately capitalized. Artech House cannot attest to the accuracy of this information. Use of a term in this book should not be regarded as affecting the validity of any trademark or service mark. 10 9 8 7 6 5 4 3 2 1

CONTENTS

PREFACE  XV

1 LITHIUM-ION BATTERY INTRODUCTION  1 1.1  Introduction 1.2  Terminology in Battery Systems 1.3  Lithium-Ion Battery System

1 6 6

1.3.1  Form Factor and Battery Cell Identification

8

1.3.2  Output Voltage

9

1.3.3  Implementation 1.4  Lithium-Ion Battery Cell Construction

9 12

1.4.1  Battery Cell Packaging Materials

12

1.4.2  Battery Cell Form Factors

13

1.4.3  The Components Used in a Lithium-Ion Battery Pack Cell Electrode Assembly

21

1.4.4  The Electrode Assembly

23

1.4.5  Graphite-Based System Operation 25 1.5  Lithium-Ion Battery Cell Performance Characteristics by Definition 27 References

29

v

vi

CONTENTS

2 BATTERY SYSTEMS ARCHITECTURES  31 2.1  The Battery Pack System

31

2.1.1  The Lithium-Ion Cell

31

2.1.2  The Charger

32

2.1.3  The Discharger

33

2.1.4  The Power Source 2.2  Lithium-Ion Battery System Subsystems

34 35

2.2.1  Battery System Power Sources

36

2.2.2  Battery Pack Charger Architectures

41

2.2.3  Battery Pack Battery Management Unit Circuit Architectures 46 2.2.4  Battery Pack Architectures

56

2.2.5  The Battery Pack Cell

67

2.2.6  The Exchangeable Battery Pack Architecture

68

2.2.7  User-Replaceable Battery Pack and Internal Device Battery Pack Charger 69 2.2.8  Nonuser-Replaceable Battery Pack and Internal Device Battery Pack Charger

69

2.2.9  Portable Power Source

71

2.2.10  The Modular Battery

72

2.2.11  Nonmodular Universal Serial Bus Storage System Architecture

74

2.2.12  Modular and Nonmodular Electrical Storage System Architecture 2.3  The Battery Pack Cell Datasheet and the Battery Pack Cell Specification References

74 76 76

3 LITHIUM-ION BATTERY SAFETY CONSIDERATIONS  77 3.1  Introduction 3.2  Product or System Reliability Versus Safety 3.3  Lithium-Ion Battery Cell Failure Causes and Modes 3.3.1  Thermal Runaway

77 80 81 81



CONTENTS

vii

3.3.2  Internal Short Circuit

84

3.3.3  Lithium Plating

86

3.3.4  Cell Failure Mechanisms

87

3.3.5  Battery Pack Failure Modes

98

3.3.6  Electrical and Electronic Component Failures

100

3.3.7  High-Voltage Isolation

104

3.3.8  Environment and Environmental Conditions to Consider

104

3.3.9  Environmental Compatibility

106

3.3.10  Critical and Unique Requirement Considerations

106

3.3.11  Recyclability

107

3.3.12  Storage

107

References

107

4 THE LAW AND BATTERY PRODUCT SAFETY  109 4.1  Introduction 4.2  The Evolution of Product Safety

109 110

4.2.1  Product Safety and Product Battery System Regulations

113

4.2.2  Product and Product Battery System Safety Control Management

113

4.2.3  Product and Product Battery System Safety Certifications 114 4.3  The Law and Product and Product Battery System Safety Compliance 114 4.3.1  Product and Product Battery System Liability

114

4.3.2  Historical Background

115

4.3.3  Types of Battery Product and Product Battery System Defects 4.4  Product and Product Battery System Compliance

118 118

4.4.1  Why is Product and Product Battery System Compliance Necessary?

118

4.4.2  Risks of Nonconformance of the Product and Product Battery System

121

References

122

viii

CONTENTS

5 REGULATORY REQUIREMENTS AND SAFETY STANDARDS  125 5.1  5.2  5.3  5.4  5.5 

Introduction International and Foreign Regulatory Organizations International Battery Standards Regulatory Organizations in the United States Battery Standards Organizations Located in the United States 5.5.1  Lithium-Ion Battery Standards in the United States

125 125 128 129 130 131

5.5.2  Description of Selected Standards Used in the United States 133 5.5.3  Procedural Test Standards

140

5.5.4  Codes and Authority Having Jurisdictions

141

References

142

6 PORTABLE CONSUMER PRODUCT BATTERY SYSTEM STANDARDS  143 6.1  Introduction 6.2  Power Source

143 146

6.2.1  AC Power Converters

146

6.2.2  Variations

147

6.2.3  Relevant Standards

147

6.2.4  Safety Compliance 6.3  Charger 6.4  Relevant Standards 6.5  Safety Compliance 6.6  The Battery Pack 6.7  Single-Series Cell Battery Pack Architecture 6.8  Series Cell and Series-Parallel Cell Lithium-Ion Battery Pack Architectures 6.9  Relevant Standards 6.10  Battery Cell 6.11  Relevant Standards 6.12  The Product Lithium-Ion Battery System 6.13  Lithium-Ion Battery System Architectures

148 151 151 152 152 152 153 154 154 155 156 156



CONTENTS

ix

6.13.1  Relevant Standards

157

6.13.2  Other Relevant Standards

160

7 MEDICAL PRODUCT BATTERY SYSTEM STANDARDS  161 7.1  Introduction

161

7.1.1  Relevant Standards 7.2  Power Source

162 162

7.2.1  AC Power Converters

162

7.2.2  Relevant Standards 7.3  Battery System Battery Charger Architectures

163 164

7.3.1  Relevant Standards 7.4  The Battery Pack

166 166

7.4.1  Typical Battery Architectures

167

7.4.2  Relevant Standards 7.5  Battery Cell

169 169

7.5.1  Relevant Standards 7.6  The Integrated Battery System

171 172

7.6.1  Relevant Standards

172

7.6.2  Implementation of the Standards 7.7  Other Relevant Standards

172 174

8 E-MOBILITY BATTERY SYSTEM STANDARDS  177 8.1  Introduction 8.2  Battery System Power Sources

177 178

8.2.1  Relevant Standards 8.3  The Battery Charger Architectures

178 179

8.3.1  Relevant Standards 8.3.2  Implementation of the Standards 8.4  The Battery Pack

182 182 183

8.4.1  The Battery Module

184

8.4.2  Relevant Standards 8.5  The Battery Cell

185 186

x

CONTENTS

8.6  The Battery System

187

8.6.1  Relevant Standards 8.7  Summary of E-Mobility Standards and Product Categories

188 188

9 AUTOMOTIVE BATTERY SYSTEM STANDARDS  199 9.1  Introduction 9.2  Chargers

199 201

9.2.1  Level 1 Charging

201

9.2.2  Level 2 Charging

201

9.2.3  Level 3 Charging

202

9.2.4  Relevant Standards 9.3  The Vehicle Battery

202 202

9.3.1  Relevant Standards 9.4  Battery Cell Standards

203 204

9.4.1  Relevant Standards 9.5  Other Relevant Standards

204 205

9.5.1  ANSI C18 Series

205

9.5.2  UL 1642 Lithium Batteries

205

9.5.3  UN/DOT 38.3 Transportation Testing 

205

9.5.4  UL 2054 Household and Commercial Batteries 9.6  Additional Product Categories

205 206

9.6.1  E-Motorcycles

206

9.6.2  E-Bike (Recreational Use)

206

9.6.3  Heavy-Duty Electric Vehicles

206

9.6.4  Electric Forklifts

206

9.6.5  Electric Autonomous Cleaners

206

9.6.6  Electric Mining Vehicles

207

9.6.7  Electric All-Terrain Vehicles and Utility Terrain Vehicles

207

10 TOY BATTERY SYSTEM STANDARDS  209 10.1  Introduction 10.2  Battery System Power Sources

209 210



CONTENTS

10.2.1  Power Converters

xi

210

10.2.2  Relevant Standards 10.3  Battery System Charger

211 212

10.3.1  Relevant Standards 10.4  The Battery Pack

213 213

10.4.1  Single-Series Cell Battery Architecture

214

10.4.2  Multiseries Cell Battery Architecture

214

10.4.3  Relevant Standards

215

10.4.4  Battery Standards 10.5  Battery Cell Standards 10.6  The Battery-Powered Product

215 215 217

10.6.1  Relevant Standards

218

11 CELLULAR DEVICE BATTERY SYSTEM STANDARDS  219 11.1  Introduction 11.2  Battery System Power Sources

219 220

11.2.1  Relevant Standards 11.3  Battery System Battery Charger Architectures

220 222

11.3.1  Relevant Standards

222

11.3.2  The Battery Pack

224

11.3.3  Battery Architectures

224

11.3.4  Relevant Standards 11.4  Battery Cell Standards 11.5  The Integrated Battery System

225 226 226

11.5.1  Relevant Standards

228

11.5.2  Relevant Product Categories and Safety Standards

228

12 CLOTHING BATTERY SYSTEM STANDARDS  231 12.1  Introduction 12.2  Battery System Power Sources

231 232

12.2.1  AC Power Converters

232

12.2.2  Relevant Standards

232

xii

CONTENTS

12.3  Battery System Battery Charger Architectures

233

12.3.1  Relevant Standards 12.4  The Battery Pack

234 234

12.4.1  Battery Pack Architectures

235

12.4.2  Relevant Standards 12.5  The Battery Cell

236 238

12.5.1  Relevant Standards 12.6  The Product-Integrated Battery System

238 238

12.6.1  Relevant Standards

238

12.6.2  Other Relevant Standards

240

13 ELECTRICAL STORAGE BATTERY STANDARDS  241 13.1  Introduction 13.2  Portable Power Pack

241 242

13.2.1  The Battery Pack System Power Source

242

13.2.2  The Battery Pack Charger Architectures

242

13.2.3  The Lithium-Ion Battery Pack

242

13.2.4  The Battery Pack Cell

243

13.2.5  The Portable Power Pack System Architecture 13.3  6V/12V Lithium-Ion Batteries

243 244

13.3.1  The Battery System Power Source

244

13.3.2  The Battery Pack Charger Architectures

244

13.3.3  The Battery Pack

244

13.3.4  The Battery Cell

244

13.3.5  The Battery System Architecture

244

13.3.6  Relevant Standard 13.4  Home Electrical Storage Systems (Home Backup Power)

245 245

13.4.1  The Battery System Power Source

245

13.4.2  The Battery Pack Charger Architectures

245

13.4.3  The Lithium-Ion Battery

245

13.4.4  The Battery Cell

245

13.4.5  The Battery System Architecture

246

13.4.6  Nonmodular Battery System Architectures

246



CONTENTS

xiii

13.4.7  Relevant Standard 13.5  Uninterrupted Power Supply Systems

246 246

13.5.1  Relevant Standard 13.6  Grid Battery Electric Storage Systems

246 247

13.6.1  The Battery System Power Source

247

13.6.2  The Battery Pack Charger Architectures

247

13.6.3  The Battery Pack Architectures

247

13.6.4  The Battery Cell

248

13.6.5  The Battery System Architecture

248

13.6.6  Relevant Standards

248

Reference

249

14 AVIATION BATTERY SYSTEM STANDARDS  251 14.1  Introduction 14.2  Battery System Power Sources

251 252

14.2.1  Relevant Standards 14.3  Battery System Charger Architectures 14.4  The Battery Pack

252 253 253

14.4.1  Relevant Standards 14.5  The Battery Cell 14.6  The Integrated Battery System 14.7  Product Category Specific Relevant Standards

253 253 254 254

14.7.1  Unmanned Commercial Drones

254

14.7.2  Passenger Winged Aircraft

254

14.7.3  Rideshare Taxis

255

15 LITHIUM-ION BATTERY SHIPPING IN THE UNITED STATES  257 15.1  Introduction 257 15.2  Local Shipping in the United States and International Shipping 257 15.3  Shipping Testing Requirements 259

xiv

CONTENTS

15.4  Lithium-Ion Battery Shipping Descriptions and Testing Requirements 15.5  Shipping Prototype Batteries 15.6  Damaged Batteries 15.7  Does Battery Size Matter? 15.8  PHMSA Document Shipping Guidelines 15.9  International Shipping 15.10  Private Shippers in the United States 15.11  Noncompliance Selected Bibliography

259 260 261 262 262 263 263 263 264

APPENDIX: THE CELL DATASHEET  265 GLOSSARY OF TERMINOLOGY USED IN BATTERY SYSTEMS  271 ABOUT THE AUTHORS  281 INDEX  283

PREFACE

Batteries play a crucial role in storing electrical energy for on-demand use, enabling the portability of electrical and electronic devices. In addition to portable batteries, energy storage systems provide another means of harnessing battery power, primarily for stationary applications. Lithium-ion battery technology and safety serves as a comprehensive technical resource designed to assist practitioners in understanding the design architectures, safety features, failure modes, and safety standards associated with lithium-ion battery systems. This book aims to integrate both the technological aspects of battery systems and the relevant safety standards into one cohesive document. Although the technology pertains to all geographical areas, the standards discussed in this book focus exclusively on the United States of America. Focusing on lithium-ion battery technology and the key certification standards prevalent in the United States, the book is structured into 15 chapters. The first three chapters—“Lithium-Ion Battery Introduction,” “Battery System Architectures,” and “Lithium-Ion Battery Safety Considerations”—provide foundational knowledge on battery technology and its potential failure modes. Chapter 4, titled “The Law and Battery Product Safety,” contextualizes product liability and underscores the importance of product safety beyond just saving lives.

xv

xvi

Preface

Chapter 5, title “Regulatory Requirements and Safety Standards,” details applicable safety standards, with an emphasis on US product compliance while acknowledging international organizations. Chapters 6 through 14 delve into the various design architectures specific to battery systems, identifying and isolating the key subsystems in the lithium-ion battery system: • Power source; • Battery charger; • Battery pack; • Battery cell; • Battery system or product. For each subsystem, relevant safety standards and testing requirements are examined, enabling readers to evaluate the subsystems individually. The final chapter, Chapter 15, addresses the shipping regulations for lithium-ion batteries in the United States, providing references to important resources as shipping standards are subject to rapid change. As regulatory landscapes shift rapidly, and new technologies emerge, this book will be updated in future editions to reflect the latest developments. Our hope is that this manual will enhance your understanding of lithium-ion battery technology and its safety standards, equipping you to navigate the complexities of new product development confidently. We hope this book enhances your understanding of lithium-ion battery technology and safety standards and that you will find this book a useful guide in the classroom as well as in the office. We would also like to extend our gratitude to Steli Lozen and Constantin Bolintineanu for their encouragement and support in initiating this project. Thank you.

1 LITHIUM-ION BATTERY INTRODUCTION

1.1  INTRODUCTION

The invention of batteries helped to practicalize the wireless mobile consumer product industry. Portable power enabled the industry to become mobile and wireless, consequently eliminating the constraints of power cables or liquid energy. However, the constant development in mobility continues to challenge battery pack technology and product efficiency. The electrochemical electrical energy storage battery has been around for more than 100 years. Mass adoption of the battery was in providing backup power to dwellings, telephones, electric vehicles, and consumer products, such as flashlights. The original zinc carbon batteries had portability but were a primary battery. Primary batteries are one-time-use batteries and cannot be recharged. Lead acid batteries were more popular in both stationary and automotive power. Vehicles were powered by lead acid in the early 1900s [1], a time when steam-powered, gas-powered, and electric-powered vehicles fought for dominance of the market. Unlike steam-powered vehicles, electric vehicles did not completely disappear from the automotive market, but lacked battery electrical energy storage for sufficient range. At the time, only lead acid batteries were available to power

1

2

Lithium-Ion Battery Introduction

electric vehicles. However, lead acid batteries were quickly adopted to provide starting power for the internal combustion engine and became an industry workhorse in the automotive industry. Lead acid batteries were also popular in stationary power applications likely due to the battery’s weight. Lead is dense and heavy, so the batteries were heavy. Lead acid is viable in stationary applications and powered applications. Lead acid batteries were rechargeable and thus called secondary batteries. Secondary batteries, in contrast to primary batteries, could be charged and discharged; therefore, secondary batteries could be used for extended periods of time without the need for replacement. Lead acid batteries are not suitable for portable consumer product applications due to their weight but are still popular in stationary backup power and vehicles due to its low cost. The popularity of mobility and portability of consumer products accelerated with the improvement of the transistor. It can be argued that the transistor, in combination with the battery technology, enabled the mobile and portable consumer market. The dominance of zinc carbon batteries and their relatively low weight at the time was sufficient to power radios, flashlights, and other portable consumer products. Nevertheless, as the sophistication of consumer products increased, and the size of consumer products decreased, the demand for smaller and higher energy-dense batteries pushed new battery chemistries in the market. The need for rechargeable batteries also pushed for development of new battery technologies. The original primary zinc carbon batteries were square, large, and heavy but the demand for smaller power packages resulted in the commercialization of smaller batteries in the cylindrical form factor of AAA, AA, B, and C sizes (see Figure 1.1). The low energy density resulted in the development of alkaline batteries, which had a much higher energy density. Lead acid batteries were complimented by lighter and more energy-dense NiCad, and NiMH secondary batteries. The increased secondary battery capabilities drove product development in the stationary energy storage space as well as consumer products and specialty applications. This led to the development of battery standards. The standards focused on consumer product safety, battery safety, and environmental considerations.



1.1  Introduction

3

Figure 1.1  A typical AAA (left) and AA (right) alkaline primary battery cell.

The exponential growth of technology, driven by the transistor, in the portable consumer product space (e.g., portable computers, cellular phones, personal assistants, and portable games) continued to drive the need for lighter, more energy dense and less costly battery technology. The need for safety and environmental standards continued to grow and expand. Lithium-ion secondary battery technology was a late arrival to the battery industry due to the challenges that had to be overcome during development. The development of lithium battery technology faced many hurdles, which continue emerging to this day. The primary lithium battery work started in 1912 under G. N. Lewis [2]. However, primary lithium batteries only became commercially available in the 1970s. Attempts were made to commercialize rechargeable lithium batteries in the mid-1980s, and subsequently in early 2000, but safety challenges could not be overcome and negatively impacted further commercialization. Lithium metal as a negative material provided

4

Lithium-Ion Battery Introduction

high energy density but the instability of lithium metal resulted in dendrite formation, sufficient to cause internal shorts within the battery [3]. The internal shorting would result in a rise of the battery cell temperature sufficiently high enough to cause battery cell thermal runaway. Thermal runaway of the battery cell can be associated with venting and flaming combustion of the battery but it depends highly on various factors, including battery cell state of charge (SOC). The drive to commercialize lithium metal rechargeable batteries is very attractive due to their high energy density, and development is ongoing. By rechargeable battery technology standards, lithium-ion battery technology seems to still be quite young. The positive active material was developed by John B. Goodenough. While Goodenough never patented cobalt oxide positive-active material, it seems that the negative material in the lithium-ion battery pack was a challenge and could not be developed to be reliable [4]. However, this piece of the lithium-ion battery technology puzzle fell into place during the late 1970s, when Samar Basu, a student at the University of Pennsylvania, demonstrated that lithium atoms can individually be stored in graphite, to prevent the formation of lithium metal [5]. Basu’s discovery allows the use of lithium, but not in lithium metal form. He achieved this by intercalating the lithium atoms into the graphite during the charge cycle of the battery pack cell, thus eliminating the formation of lithium metal. This was a key development in the technology that eliminated lithium dendrite growth under normal operating conditions. During the 1980s, a couple of other technological breakthroughs occurred and in 1991 Sony took out a once highly disputed patent on lithium cobalt oxide positive-active material and commercialized rechargeable lithium-ion battery technology using coke as the negative material. This type of lithium battery technology is referred to as lithiumion batteries and should not be confused with lithium batteries. The construction between these two types of lithium-based batteries is different. A lithium-ion battery pack (see Figure 1.2) consists of one or more battery pack cells packaged together to form the lithium-ion battery pack. The construction of lithium-ion battery cells makes the lithium-ion battery pack lighter and enables it to store significantly



1.1  Introduction

5

Figure 1.2  Lithium-ion battery packs.

more electrical charge (meaning very high energy density) compared to other commericially available battery chemistry technologies. Similar to the importance of the development of the transistor in the 1940s in shaping the future, so was the development of lithium-ion battery technology in the 1970s. Lithium-ion battery pack technology has reshaped our world and will continue to shape our future. The complexity of lithium-ion battery system technology was a challenge that was met with enthusiasm. Industries adopting lithiumion battery technology had to develop different internal processes and design requirements and standards. Successful incorporation of this technology ensured reliability and a safe product. The following sections and chapters provide a fundamental lithium-ion battery system introduction. The additional context will provide insight into the risks, considerations, and application of various standards and requirements.

6

Lithium-Ion Battery Introduction

1.2  TERMINOLOGY IN BATTERY SYSTEMS

Like all technologies, there is terminology that is unique and specific to battery systems used in the context of the battery industry. Furthermore, there are specific terms that are associated with lithium-ion batteries, for example, the definitions of the battery pack cell, the battery pack, the charging system, and the battery system. Understanding the meaning of the relevant terminology will enable the reader to better understand and interpret the battery system and subsystems datasheets and/or specifications. A list of terms and definitions is listed in the glossary. The glossary consists of only a subset of terms and definitions used in the industry. However, for the purpose of this book, the terms listed are important in providing the correct context for this book’s content.� 1.3  LITHIUM-ION BATTERY SYSTEM

The application of commercial lithium-ion batteries is similar to older battery chemistries. However, the characteristics and battery system and subcomponent designs are more complex. Figure 1.3 is a simplified block diagram showing how requirements influence energy delivery, battery cell characteristics that in turn affects measurable parameters and battery safety and performance. The impact of user requirements can be observed in Figure 1.3. Often user requirements may include charge and discharge times, battery capacity, battery system physical size, and safety. If we, for example, evaluate safety as a user requirement, a block diagram can be constructed to show that the choice of battery architecture, enclosure design, diagnostics choice of battery pack cell chemistry, and safety components or circuits are affected. The same visual representation can be crafted, for example, for charge and discharge times and identifying the affected items. Understanding the user requirements and their impact on the battery system requires an understanding of the battery system, cell chemistry, control and safety control circuits, selecting and integrating the correct battery pack cells, and safety performance. Further insight into these requirements is provided in the remainder of this chapter, and Chapters 2 and 3.

1.3  Lithium-Ion Battery System

Figure 1.3  The items in the battery system affected by the user requirements. (Used with the permission of Exponent, Inc.)

7

8

Lithium-Ion Battery Introduction

1.3.1  Form Factor and Battery Cell Identification

Primary alkaline and secondary NiCAD and NiMH batteries are predominantly commercialized in battery sizes such as AAA, AA, B, C, or CR123 for consumer applications but other form factors are available for industrial applications. The higher output voltage of lithium-ion batteries made this technology initially incompatible with the AAA, AA, B, C, or CR123 battery sizes. Lithium-ion technology has demonstrated flexibility in battery sizes and form factor, capacity and performance characteristics, and form factor standardization is to date not a predominant feature of lithium-ion battery cells or batteries. This flexibility allows for product development to dictate battery cell size based on the user requirements and not industry requirements. In contrast, the compatible output-voltage of NiCAD and NiMH rechargeable batteries enables compatibility between traditional alkaline and NiCAD and NiMH batteries. Table 1.1 shows a subset of lithium-ion battery cell sizes and their diameters and lengths, and how it correlates to the sizes of alkaline, NiCAD, and NiMh batteries. The table shows that lithium-ion battery cell identification is often derived from the dimensions of the battery cell. For example, with cylindrical battery cells, the first two numbers of the battery cell will be the battery cell diameter and the remaining three numbers may be the battery cell length. Both these measurements are in millimeters. Table 1.1 Subset of Lithium-Ion Battery Cell Sizes and Their Primary Battery Cell Equivalents Cylindrical Cell Identification Number

Diameter (mm)

Length (mm)

Notes

10440

10

44

The size is the same as a AAA battery cell.

14500

14

53

The size is similar to a AA battery cell.

18650

18

65

Most common battery cell sizes used in many applications, for example, e-vapor devices, consumer products, power tools, vehicles–to name a few.

2170

21

70

Larger version than the popular 18650.

26500

26

50

About the same dimension as a C battery cell.

32600

32

60

The size is the same dimension as a D battery cell.

4680

46

80

For use in automotive batteries.



1.3  Lithium-Ion Battery System

9

For rectangular prismatic cells, the first two digits will represent the thickness of the battery cell in prismatic battery cells. The second two digits will represent the width of the battery cell. The last two digits will indicate the length of the battery cell. The first two digits will represent the diameter in button battery cells, while the last two digits will indicate the thickness of the battery cell. The diameter of the battery cell is presented in millimeters and the thickness of the battery cell is presented in decimeters. Typically, measurements are in millimeters. 1.3.2  Output Voltage

Depending on the cell chemistry composition, for a lithium-ion cell, the nominal voltage typically ranges between 3.2V and 3.8V (an everchanging range) [6]. The traditional alkaline, NiCAD, and NiMH batteries have output voltages ranging between 1.2V and 1.5V. Therefore, lithium-ion battery cells are not interchangeable with traditional alkaline, NiCAD, and NiMH batteries without the use of electronic circuits changing the battery cell voltage. An example of a AAA lithium-ion battery marketed to be a replacement for primary AAA (similar to AA, B, and C cylindrical formats) is shown in Figure 1.4. In order to produce lithium-ion batteries in the commercial standardized cylindrical sizes, and to be output voltage compatible, the output voltage of the lithium-ion battery cell must be altered to 1.5V. The output voltage is reduced by adding a DC-DC converter providing an output voltage of 1.5V. This circuit is usually incorporated into the A-, AA-, AAA-, B-, or C-sized battery enclosure. The additional electronic circuit adds complexity to the lithiumion battery system design. The hybrid lithium-ion batteries cannot be charged using the chargers for NiCAD and NIMH batteries and typically needs to be charged through an integrated USB or power port. 1.3.3  Implementation

The term battery is used interchangeably when referring to a single battery cell, for example an alkaline 1.5V battery, or a cluster of battery cells, for example a vehicle’s 12V battery. However, in lithiumion batteries there is a distinct difference between battery pack cells and battery packs.

10

Lithium-Ion Battery Introduction

Figure 1.4  A lithium-ion battery pack in the AAA format.

Typically, in nonlithium-ion terms, a single battery cell or the cluster of battery cells are most often referred to as a battery. The batteries only consist of electrochemical cells with some form of labeling or enclosure. Typically, zinc carbon, alkaline, NiCAD, NiMH, and lead acid batteries tend to fall in this category and can be found in the same physical sizes, and hence may be interchangeable. The batteries can be use in various products designed to use the specific form factor batteries. In contrast, with lithium-ion batteries, the electrochemical cells and the lithium-ion battery pack consist of a combination of battery cells wiring, and electronic protection circuits, and an enclosure, all interdependent, but functioning in a single unit called a battery pack. The lithium-ion battery packs are generally not distributed to the end user as an interchangeable battery or used in a variety of products. If lithium-ion battery cells are used in a product, a battery cell with an altered protruding battery cell positive terminal will be used, as shown in Figure 1.5. In this case, the product will also be designed to accept the protruding positive terminal-shaped battery cell and not the flat positive terminal battery cell.



1.3  Lithium-Ion Battery System

11

Figure 1.5  Example of a flat (green battery cell) and a button (pink battery cell)

lithium-ion battery cell positive terminal. The red arrows show the positive terminal of the battery cell.

Lithium-ion battery cells with flat terminal are designed to be permanently integrated into battery packs and the geometry is designed to accept spot-welded bus bars. There are many form factors for lithium-ion cells and battery packs available on the market, and the battery cells can be shaped and sized on request. Therefore, lithium-ion batteries are generally product and product-model specific.

12

Lithium-Ion Battery Introduction

1.4  LITHIUM-ION BATTERY CELL CONSTRUCTION

Lithium-ion battery cells do not produce gas during normal operation. The electrolyte is not consumed and does not need to be topped up. To protect the electrodes from exposure to air, moisture, and evaporation, the lithium-ion electrochemical battery cell is hermetically sealed in packaging material. 1.4.1  Battery Cell Packaging Materials

There are typically three types of battery cell or electrode packaging material. Nickel-coated steel, aluminum, or a polymer pouch lined with aluminum foil. The battery cell packaging materials using nickel-coated steel or aluminum materials provide great mechanical stability. The cell packaging is referred to as the battery cell-can. The type of battery cell packaging material plays a role in the volumetric energy density, gravimetric density, and cell assembly process. Nickel-coated steel can require either a crimping process or laser welding process to seal the open end. Similarly, aluminum can metallic material requires a laser weld to seal the open end of the battery cell. Nickel-coated steel may be lighter than aluminum, but a positive aspect of both construction materials is that safety protection features and devices, such as battery cell vent mechanisms, may be incorporated into the cell-can design. In contrast, polymer-type packaging materials, such as aluminum foil coated with a polymer layer, can be shaped into a pouch. The wall size results in negligible battery cell assembly size and weight contribution. Therefore, the impact on the volumetric energy density of the battery cell as well as the gravimetric density of the battery cell is less. In addition, reduced production cost may be an advantage. However, using an aluminum polymeric pouch has one major drawback; the pouch offers no mechanical stability to the battery cell construction and any mechanical impact is directly transferred to the battery cell electrodes. This construction does not typically allow for passive safety features to be incorporated into the battery cell pouch design. Pouch-constructed prismatic cells are often referred to as lithium polymer cells.



1.4  Lithium-Ion Battery Cell Construction

13

1.4.2  Battery Cell Form Factors

There are three form factors in lithium-ion battery cells. The first form factor is the cylindrical battery cell, the second is the rectangular prismatic battery cell shape, and finally, the button or coin battery cell shape. It is not known where the name prismatic originates from and how the triangle name relates to a rectangular shape of the prismatic battery cell. Perhaps the flat surfaces associated with a rectangular prismatic shape differentiates the battery cell shape from the round cylindrical shape associated with a cylindrical battery cell, and in this book the authors will continue to use the term prismatic to describe the rectangular battery cell shape. Button cells are typically disk-shaped or doughnut-shaped battery cells. Another differentiator between cylindrical and prismatic battery cells versus button battery cells is their application. Button battery cells are usually very small capacity battery cells used in environments that require low power consumption. There are certain advantages and disadvantages when choosing a battery cell form factor. The form factor advantages do not relate to the performance of the electrochemistry, but perhaps are more focused on cost, the design constraints, and potentially the safety features of the battery cell. It is, therefore, important to consider these characteristics of the battery cells during the design of the battery system. When the battery is certified it is desirable to have the most suitable technology providing the biggest safety margin in your battery system design. 1.4.2.1  Cylindrical Battery Pack Cells

The cylindrical battery cell (Figure 1.6) can be constructed using a pouch or metallic can, although the metallic can construction is more popular. Cylindrical battery cells be obtained in a power battery pack cell or an energy battery pack cell. The capacity of power battery pack cells is typically less compared to the equivalent energy battery pack cells size due to the construction of the cells having to deliver larger currents. An X-ray computed tomography (CT) image of a cell-can constructed cylindrical cell is shown in Figure 1.7. The positive terminal is at the crimped end of the battery pack cell (Figure 1.7(a)). There

14

Lithium-Ion Battery Introduction

Figure 1.6  Cylindrical lithium-ion battery pack cells. The cylindrical battery pack

cell on the left has a metallic battery cell-can, and the cylindrical battery cell on the right has a polymer aluminum foil pouch.

may also be a burst disk that will open and release the internal pressure when the battery cell internal pressure increases above a safe limit (Figure 1.7(b)). A current interrupt device (CID) (Figure 1.7(c)) embedded in the battery cell end-cap assembly (features that may have to be specified when the battery cells are purchased). Energy battery pack cells will typically have a positive temperature coefficient (PTC) gasket (Figure 1.7(d)). The PTC is a current-limiting device that limits the charge or discharge current of the battery pack cell once a certain safe level is exceeded. This is feature ensures that the battery cell does do not overheat. The burst disk is combined with an electrical contact (see contacts in Figure 1.7(c)), electrically connecting the battery pack cell positive electrode to the battery pack cell positive terminal. This assemble will activate when the pressure in the battery cell increases



1.4  Lithium-Ion Battery Cell Construction

15

Figure 1.7  The cross section of the positive terminal. A show the positive terminal. B

shows the burst disk. C shows the CID contacts. Point D shows the PTC and/or battery cell gasket. (Used with the permission of Exponent, Inc.)

due to temperature, overheating of the battery cell, or irreversible chemical reactions causing gas generation and, consequently, pressure buildup in the battery cell. The CID will open and electrically disconnect the positive electrode from the battery pack cell positive terminal to terminate any further charge or discharge current. This action effectively electrically removes the battery pack cell from a circuit. The burst disk is also designed to release any pressure buildup within the battery pack cell-can so that during a battery pack cell thermal runaway event the pressure inside the battery pack cell could be released in a controlled manner. Power battery pack cells typically do not have a PTC because the battery cell is design to deliver large currents. The power battery pack cell may be manufactured a CID which is integrated into the burst disk assembly located in the positive terminal assembly of the battery pack cell (feature that needs to be specified

16

Lithium-Ion Battery Introduction

when the battery cells are purchased). This distinct feature changes the way the battery pack cell is designed. The CID is part of the battery cell vent assembly and consists of a dome burst disk located in the positive terminal assembly of the battery pack cell. The burst disk is combined with an electrical switch that connects the battery pack cell positive electrode to the battery pack cell positive terminal. This assembly will activate when the pressure in the battery cell increases due to temperature, overheating of the battery cell, or irreversible chemical reactions causing gas generation and, consequently, pressure buildup in the battery cell. The CID will open and electrically disconnect the positive electrode from the battery pack cell positive terminal to terminate any further charge or discharge current. This action effectively removes the battery cell from a circuit. The burst disk is also designed to release any pressure buildup within the battery pack cell can so that during a battery cell thermal runaway event the pressure inside the battery pack cell could be released in a controlled manner. Cylindrical battery pack cells can also be manufactured using a pouch as the packaging material. The pouch seam is thermally bonded together after the battery cell electrodes are inserted into the pouch. The pouch construction allows for the same form factor but that is where the similarities stop. In pouch cylindrical battery pack cells, the negative and the positive terminals exit the battery cell on the opposite sides of the battery cell. The battery pack cell construction is such that the battery pack cell packaging cannot accommodate a CID or PTC. The battery cell pouch will inflate and vent at the weakest point in the pouch seam to release the internal pressure. Protection devices are not incorporated into the design and if required, a thermal cutout (TCO) or PTC may have to be added as an external series component to the battery pack cell in the electrical circuit. There are advantages to cylindrical metallic battery cells: • The technology is mature; • They are easy to manufacture in automated production lines; • When packaged, they allow for voids for cooling; • An activated CID in a battery cell will electrically isolate battery cell from the battery pack;



1.4  Lithium-Ion Battery Cell Construction

17

• When battery cell venting occurs, the vent jet flow direction can be estimated. There are also disadvantages of cylindrical battery pack cells: • The round shape does not allow for optimal space utilization when packaging the battery cells in a battery pack or module. However, when cooling is required, the voids created by adjacent battery pack cells may aid air cooling. • In pouch-constructed cylindrical battery cells, the pouch does not provide mechanical stability. • In pouch-constructed cylindrical battery cells, the vent location cannot always be predicted. 1.4.2.2  Pouch and Prismatic Battery Pack Cells

Metal-can prismatic battery pack cells are square, rectangular shaped (Figure 1.8) battery pack cells. The battery cell-can is usually positive, and the open-end cap is usually laser welded closed. The negative terminal is in this part of the battery pack cell. These battery pack cells can be obtained in a power battery pack cell configuration and an energy battery pack cell configuration. The capacity of power battery pack cells may be less compared to the equivalent energy battery pack cells size due to the thicker current collectors. This venting mechanism can be in the battery cell end-cap assembly as shown in Figure 1.8 (features that need to be specified when the battery cells are procured) or could be a scourge mark on the side of the battery cell-can wall as shown in Figure 1.9. Rarely TCO or PTC current-limiting or temperature-limiting devices are incorporated in prismatic battery cell packaging designs. These devices usually will be an add-on externally to the battery pack cell. Unlike cylindrical cells, the venting mechanism is not combined with a CID function, electrically isolating the electrodes from the battery pack cell terminals. However, the venting mechanism, or venting scourge mark (Figure 1.9), is designed to activate when the gas pressure inside the battery cell increases past a safe pressure limit which can happen due to external temperature, internal overheating of the battery pack cell, or irreversible chemical reactions causing gas generation exceeding the battery pack cell-can pressure safe limit. Once the

18

Lithium-Ion Battery Introduction

Figure 1.8  The prismatic battery cell. The red arrow indicates the location of the

battery pack cell venting mechanism.

burst disc is activated, the battery cell electrodes are still connected to the battery cell-can and the negative terminal. Power battery cells and energy battery cells will share the same design and any current limiting safety features will have to be externally added to the battery pack system circuit. Prismatic battery pack cells can also be manufactured using a pouch as the electrode packaging material and are, in general, referred to as pouch cells. The pouch seam is thermally bonded together after the battery pack cell electrodes are inserted into the pouch. The pouch construction allows for the same form factor but that is, also, where the similarities stop. In pouch cylindrical battery pack cells, the negative and the positive terminals are metallic tabs, usually protruding from the pouch assembly. The pouch battery pack cell construction is such that the battery pack cell packaging cannot accommodate a pressure activated CID or an over-current PTC. Prismatic battery pack



1.4  Lithium-Ion Battery Cell Construction

19

Figure 1.9  The scourge mark showing the venting location on the battery cell can

(see red arrow).

cells are often installed in the product with a TCO device that is temperature activated. This device will electrically isolate the battery cell once the battery cell temperature reaches a certain temperature or when an over current exceeding the capability of the TCO is detected. When the battery pack cell pouch inflates venting will occur at the seam of the pouch. The advantages of pouch and prismatic battery cells are: • The technology is mature; • Battery cells can be designed to be any shape; • Battery pack cells form factor can be very flexible; • They are easy to manufacture in automated production lines; • They allow for very dense packaging in a battery pack or module; • When battery cell venting occurs, in metal can battery cells, the vent jet stream can be estimated.

20

Lithium-Ion Battery Introduction

There are also disadvantages associated with pouch and prismatic battery pack cells: • Cell pouches can leak electrolytes when the seam bonding fails; • Soldering on pouch battery pack cell tabs may damage the battery pack cell pouch which can lead to air exposure and electrolyte leakage; • Cooling the battery pack prismatic cells can be challenging as no natural voids for air flow are created; • The battery pack prismatic cells may not have an internal mechanism that allows a battery cell to be electrically disconnected from its parallel peers; • In pouch prismatic battery cells, the pouch does not provide mechanical stability; • In pouch prismatic battery cells, the vent location cannot always be predicted. 1.4.2.3  Button or Coin Lithium-Ion Battery Pack Cells

Button battery pack cells are round disk-shaped battery cells (Figure 1.10). The battery cell consists of two shells. A smaller shell is crimped into the larger shell using a gasket. This forms a hermetically sealed cavity where the electrodes will be located. The larger shell is usually the negative of the battery pack cell and the smaller shell is the positive of the battery pack cell. The capacity of these battery pack cells is typically low, limited by their size. A large, commercially available rechargeable coin battery button cell is, for example, a CR3555 button cell, which has a nominal voltage of 3.7V and a capacity of 300 mAh. Generally, coin battery pack cells are not used in power applications but rather energy applications. Coin battery cells do not usually have dedicated venting mechanisms. When the internal battery cell pressure increases, the two shells will separate to release the internal pressure. Often these battery cells are not equipped with a PTC current-limiting device or a TCO but require the same protection circuits associated with other format lithium-ion battery pack cells.



1.4  Lithium-Ion Battery Cell Construction

21

Figure 1.10  A typical button or coin battery cell.

1.4.3  The Components Used in a Lithium-Ion Battery Pack Cell Electrode Assembly

The lithium-ion battery pack is unique compared to NiCAD, NiMH, and lead acid in two distinct ways. The first is that the electrodes do not experience a structure change during charge and discharge. Secondly, the electrolyte is organic. Lithium-ion battery pack cells have a very well-defined operational window for operating voltage, charge discharge current, and operating temperature. The positive material, negative material, the separator, the electrolyte, and the current tabs form the lithium-ion jelly roll, and adding the cell-packaging components form the lithium-ion battery pack cell. The components can consist of different materials that provide the properties of the specific battery pack cell design in terms of specific energy, charge rates, discharge rates, life, safety, and the cost of the battery cells. To become familiar with this technology, a brief description of the battery pack cell construction follows. The information is mere-

22

Lithium-Ion Battery Introduction

Table 1.2 Various Types of Lithium-Ion Battery Cell Positive Active Materials Type of LithiumIon Battery Cell

Positive Electrode Active Material

NCA

Lithium nickel cobalt aluminum oxide (LiNiCoAlO2)

LCO

Lithium cobalt oxide (LiCoO2)

NMC (NCM)

Lithium nickel cobalt manganese oxide (LiNiCoMnO2)

LNMO

Lithium nickel manganese spinel (LiNi0.5Mn1.5O4)

LFP

Lithium iron phosphate (LiFePO4/C)

LMO

Lithium manganese oxide (LiMn2O4)

From: [7].

ly an introduction. We encourage the reader to further research and familiarize themselves with this amazing technology. 1.4.3.1  Positive Electrode

The positive electrode consists of an aluminum current collector with a layer of active material coated on the aluminum substrate. The active material is a lithium salt-based blend that will be the source of the lithium-ions in the battery cell system. Depending on the specific energy, charge rates, discharge rates, life, safety, and the cost of the battery cells, along and other factors, a specific positive plate active material will be selected. A subselection of positive electrode active materials is shown in Table 1.2; there are many more. Each of the positive active material blends provide the battery pack cell with certain characteristics that may be desired for a specific application. Safety, power delivery, and capacity are often characteristics to consider when selecting the battery pack cell model. 1.4.3.2  Negative Electrode

The negative electrode consists of a copper substrate. This substrate is coated with graphite or coke. Today, graphite, in the natural as well as the synthetic form, is popular to use. The positive electrodes in Table 1.2 are used with a negative graphite electrode. The solid electrolyte interface (SEI) layer forms on the negative graphite electrode surface at the interface between the graphite and the electrolyte and is critical in maintaining the operation and safety of the battery pack. There are other materials, such as titanate oxide negative electrodes, but those chemistries are not discussed in this section.



1.4  Lithium-Ion Battery Cell Construction

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1.4.3.3  Separator

The separators used in lithium-ion battery pack cells are typically a polypropylene or polyethylene-based material. The main goal of the separator is to provide electrical isolation between the positive and the negative electrodes while allowing lithium-ions to move freely between the positive and the negative plate. In order to achieve this, the separator material is extruded to form small holes in the material, big enough for the lithium-ions to migrate through. To improve the thermal stability of the separator material, ceramic coating is often deposited on the surface of the separator. The coating is sufficiently porous to allow lithium-ion traffic to pass through yet provides increased thermal stability at higher temperatures. Chemical stability may be obtained by coating the separator with an aluminum oxide layer. 1.4.3.4  Electrolyte

The electrolyte used in lithium-ion battery pack cells is nonaqueous based. The electrolyte normally consists of lithium hexafluorophosphate (LiPF6) salts and organic carbonate solvents such as ethylene carbonate (EC). The electrolytes are temperature-sensitive and typically only stable over temperature ranges between –20° to 60°. Side reactions start to form above these temperature ranges and the electrolyte may start to decompose. The decomposition of the electrolyte affects the stability of the SEI layer and, hence, the reliability and safety of the lithium-ion battery pack cell. Additives can be added to the electrolyte to increase charge voltage and capacity, and also increase stability and safety. 1.4.4  The Electrode Assembly

The electrode assembly contains the polymer separator that is sandwiched between the positive and the negative electrodes. There are four popular configurations: spiral-wound cylindrical lithium-ion (Figure 1.11), spiral-wound prismatic lithium-ion (Figure 1.12), stacked electrodes (Figure 1.13), and Z-stacked electrode assembly. The electrode assembly is typically chosen based on the battery cell form factor and/or the battery cell application. In cylindrical battery cells a jelly roll design is implemented due to the round shape of the battery pack cell-can and this architecture is used irrespective of whether the battery pack cell is a power or an energy battery cell.

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Lithium-Ion Battery Introduction

Figure 1.11  Spiral-wound lithium-ion battery pack cell electrode assembly. The red

arrows show the spirally wound electrode assembly.

Figure 1.12  Spiral-wound prismatic shape lithium-ion battery pack cell electrode

assembly. The red arrow shows the spirally wound electrode assembly: (a) the positive electrode, (b) the polymeric separator, and (c) the negative electrode.

The same is not the case with prismatic battery cells where the shape of the battery cell allows for more variations on the design of the



1.4  Lithium-Ion Battery Cell Construction

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Figure 1.13  Stacked lithium-ion battery pack cell electrode assembly. The red arrow

shows the stacked electrode assembly: (a) the negative electrode, (b) the polymeric separator, and (c) the positive electrode.

electrode assembly. For example, in prismatic battery cells, stacked electrode assemblies and flat wound electrode assemblies are used. Often, stacked assemblies are used in power battery cell applications as each individual electrode is electrically connected to the battery pack battery cell output terminal, which allows for a lower internal resistance of the battery pack cell and larger power delivery. 1.4.5  Graphite-Based System Operation

The electrochemical system in a lithium-ion battery cell is unique in the sense that it uses a process of intercalation. In the context of lithium-ion battery cells, the process of intercalation is the insertion of atoms or ions between layers in a crystal lattice. The operation of the lithium-ion battery pack cell is as follows. The lithium atoms are located inside the crystal lattice in the lithium salt positive active material and the graphite (carbon) lattice in the negative material (Figure 1.14). Lithium is not, in metal form, present in the chemical system of a lithium-ion battery pack cell, and this is the fundamental reason lithium-ion technology functions safely as a secondary rechargeable battery pack cell. On the left of Figure 1.14 is the lithium salt negative electrode and on the right is the graphite (or titanite) positive electrode. The blue lithium atoms are intercalated in the crystal lattice and graphite. The brown line is the SEI layer, and the green line is the separator. Lithium-ions move between the positive and the negative elec-

26

Lithium-Ion Battery Introduction

Figure 1.14  The lithium-ion chemical system during charge and discharge.

trodes in synchronization with their electrons in the external charge or discharge circuit. When a lithium-ion battery pack cell is connected to a charger, the lithium atom will oxidize (lose an electron), move out of the positive active material crystal lattice, through the electrolyte as an ion, through the separator pores to the electrolyte on the negative electrode side, then through the SEI layer, and finally into the graphite lattice where it reduces (gains an electron) to a lithium atom. The lithium atoms are intercalated into the graphite, become isolated from other lithium atoms, and prevented from forming lithium metal. When the lithium-ion battery pack cell is connected to a load to discharge, the lithium atom will oxidize in the negative electrode graphite lattice, migrate out of the crystal lattice into the electrolyte as a ion at the negative electrode side of the separator, move through the separator pores to the electrolyte on the positive electrode side of the battery pack cell, and then reduce in the lithium salt crystal lattice as a lithium atom. Therefore, each lithium-ion that moves from the positive electrode to the negative electrode results in one stored electron charge, and each lithium-ion that migrates from the negative electrode to the positive electrode provides the power of one electron charge. The designed amount of usable lithium in the lithium-ion battery cell system therefore determined the amount of charge the battery cell can store and provide to a load.



1.5  LITHIUM-ION BATTERY CELL PERFORMANCE CHARACTERISTICS

27

Lithium-ion battery cells can be chosen for a specific product and usage pattern. The different types of positive active materials, negative materials, electrode amplicity, separator, and electrolyte formulations are responsible for the battery cell. Understanding the unique requirement of the battery system design and combining it with the characteristics of a suitable battery cell is very important to achieve the goal of a reliable and safe battery system. 1.5  LITHIUM-ION BATTERY CELL PERFORMANCE CHARACTERISTICS BY DEFINITION

Lithium-ion batteries and battery pack cells can be designed and manufactured for specific electrical applications requirements. A diagram can be used to show the strengths and weaknesses of a specific battery pack cell design. The axes can be determined based on the parameters that are important for the intended application. In the following example from BatteryUniversity.com, they chose specific energy, specific power, safety, performance, life, and cost (Figure 1.15). However, if specific parameters such as gravimetric energy and/ or temperature performance and/or maximum operating voltage, are important, then those axes can be added or parameters not applicable may be substituted. For example, the battery pack cell characteristic diagram may change and include specific power, safety, performance, life, gravimetric energy, temperature performance, and maximum operating voltage. The battery pack cell characteristic diagram is a visual display showing the specific characteristics of various battery pack cell chemistries and designs. An example of a visual presentation of a battery pack cell is shown in Figure 1.16. In this case, the battery cell has a high specific energy, high specific power, low safety performance, great charge and discharge performance, average cycle life, and cost is relatively low. Hence, if a specification requires a battery pack cell with a high specific energy, high specific power, high charge and discharge rates, and average cycle life can tolerate low safety performance, and low cost is a tradeoff, then this battery cell seems to be a suitable candidate to consider. Therefore, the requirements of battery cells are important to characterize to ensure safety during operation and practical to use in

28

Lithium-Ion Battery Introduction

Figure 1.15  A typical lithium-ion battery pack cell characteristics diagram [8].

an application. Utilizing a battery pack cell characteristics diagram provides a visual aid to facilitate in deciding which battery pack cell chemistry and characteristics may provide the best performance solution for an application. This section showed all lithium-ion battery cell designs are the same and that the differences between the positive and negative active materials can affect the performance characteristics of the battery pack cell. To select and design a safe lithium-ion battery system, the product specification needs to be understood. A battery pack cell is selected, using its datasheet, the battery pack cell datasheet is compared and compatible with the product specification in its entirety. In order to do so, it is important to correctly interpret the lithium-ion battery pack cell datasheet parameters as shown in the glossary. The combination of the battery pack cell chemistry, performance characteristics of the battery pack cell and the application of the battery pack cell dictates the design of the lithium-ion battery pack and



1.5  LITHIUM-ION BATTERY CELL PERFORMANCE CHARACTERISTICS

29

Figure 1.16  A visual presentation of the characteristics of a specific battery cell

chemistry and design (the legs can be marked to scale).

battery system. Different lithium-ion battery design architectures based on product categories are discussed in Chapter 2. References [1] Swart, J., S. Dalal, and D. Parker, “Electrification of the Vehicle–Where Did It Start and How Far Have We Come?” The Battery Show, The Expo for Advanced Batteries, Detroit, MI, 2012. [2] Lewis, G. N., and F. G. Keyes, “The Potential of the Lithium Electrode,” Journal of the American Chemical Society, Vol. 35, 1913, pp. 340–344. [3] Beard. K, T. B. Reddy (eds.), Linden’s Handbook of Batteries, Fifth Edition, New York: McGraw Hill, 2019, p. 755. [4] Mizushima, K, J. C. Jones, P. J Wiseman, and J. B. Goodenough, “Lix CoO2 (0