Lithium-ion Battery Failures in Consumer Electronics

This comprehensive resource caters to system designers that are looking to incorporate lithium ion (li-ion) batteries in their applications. Detailed discussion of the various system considerations that must be addressed at the design stage to reduce the risk of failures in the field is presented. The book includes technical details of all state-of-the-art Li-on energy storage subsystems and their requirements, and provides a system designer a single resource detailing all of the common issues navigated when using Li-ion batteries to reduce the risk of field failures. The book details the various industry standards that are applicable to the subsystems of Li-ion energy storage systems and how the requirements of these standards may impact the design of their system. Checklists are included to help readers evaluate their own battery system designs and identify gaps in the designs that increase the risk of field failures. The book is packed with numerous examples of issues that have caused field failures and how a proper design/assembly process could have reduced the risk of these failures. Artech House Power Engineering Library Lithium-Ion Battery Failures in Consumer Electronics 1 Preface 14 1 Lithium-Ion Cells 18 1.1 Other Cell Chemistries 19 1.1.1 Lead Acid 20 1.1.2 NiCd 20 1.1.3 NiMH 20 1.2 Li-Ion Cell Operation 21 1.3 Li-Ion Cell Varieties 22 1.3.1 Cathode Materials 23 1.3.2 Anode Materials 24 1.3.3 Separator 25 1.3.4 Electrolytes 26 1.3.5 Current Collectors 26 1.3.6 Solid Electrolyte Interface Layer 26 1.4 Cell Construction 27 1.4.1 Prismatic Cells 27 1.4.2 Cylindrical Cells 27 1.4.3 Pouch Cells 28 1.5 Battery Management System for Li-Ion Cells 29 1.6 Charger Circuits for Li-Ion Cells 29 1.7 End of Life 30 1.8 Shelf Life 32 1.8.1 Life Test and Verification Process 33 1.9 Cycle Life 34 References 35 2 Overview of Li-Ion Battery Systems 38 2.1 Single-Cell Li-Ion Battery Systems 39 2.2 Multicell Li-Ion Battery Systems 42 2.2.1 Other Configurations 44 2.3 Automotive Battery Systems 44 2.4 Battery Systems for Large-Scale Energy Storage Systems 45 References 47 3 Power Supplies for Portable Consumer Electronic Products 48 3.1 Components of a Typical AC-DC Converter (AC Adapter) Circuit 49 3.2 AC Adapter Requirements 53 3.2.1 Propagating Circuit Board Failures 54 3.2.2 Burn Hazards 55 3.2.3 Component Derating 61 3.2.4 Power Supply Efficiency 64 3.2.5 Single Points of Failure 65 3.2.6 Power Supply Connectors 67 3.3 Adapter Specifications 68 3.4 Power Supply Construction and Assembly Issues 68 3.4.1 Input Power Connection 69 3.4.2 Electrolytic Capacitors 70 3.4.3 Mechanical Damage and Access to High Voltages 72 3.4.4 Creepage and Clearance Distances 72 3.4.5 Soldering/Contaminants and Other Assembly Issues 74 3.5 Testing AC Adapters 75 3.5.1 Electrical Characterization Tests 75 3.5.2 Thermal Characterization Tests 76 3.5.3 Mechanical Abuse Tests 77 3.5.4 Single Points of Failure Tests 77 3.6 DC-DC Converter Circuits 78 References 80 4 Li-Ion Battery Pack Charge Circuits 84 4.1 Charge Profile 85 4.2 Safety Timers 87 4.3 Battery Temperature Monitoring 88 4.3.1 Charging Li-Ion Cells at Low Temperatures 88 4.3.2 Charging Li-Ion Cells at High Temperatures 90 4.4 Battery ID 90 4.5 Charger Specifications and Requirements 91 4.6 Charger Circuit Construction and Assembly Issues 93 4.7 Testing Charger Circuits 94 4.8 Wireless Charger Circuits 99 References 101 5 Battery Protection Circuit Consideration 102 5.1 Need for a Protection Circuit 102 5.2 Single-Cell Battery Packs 107 5.3 Multicell Battery Packs 112 5.4 Large Battery Packs 116 5.5 Battery and PCM Specifications 117 5.6 PCM Design Review Tools 121 5.7 PCM Construction and Assembly Issues 122 5.7.1 Single-Cell Battery Packs 122 5.7.2 Multicell Battery Packs 123 5.8 Cell Failure Predictions 125 5.8.1 Cell Resistance as a Predictor of Failure 126 5.9 Testing PCMs 128 5.10 Summary 131 Appendix 5A: Electric Shock Hazards 131 References 135 6 Industry Standards and Testing 136 6.1 Commonly Used Standards to Evaluate Li-Ion Cells and Batteries in Portable Consumer Electronic Devices 136 6.1.1 UN Transportation Requirements 137 6.1.2 Underwriters Laboratories Testing Requirements 138 6.1.3 IEC Standards 144 6.1.4 IEEE Standards 146 6.1.5 Comparing Standards 146 6.2 Other Tests 147 6.2.1 Forced Internal Short-Circuit Test 147 6.2.2 Nail Penetration Test 150 6.2.3 Thermal Stability Test 151 6.2.4 Dent/Pinch Test 152 6.3 Predicting Li-ion Cell and Battery Shelf Life 152 6.3.1 Capacity Degradation 153 6.3.2 Calendar Aging 154 6.3.3 Fit Method 154 6.3.4 Time Dependence 155 6.3.5 Summary 156 Appendix 6A: International Organizations and Standards 156 Appendix 6B: Common Tests in Industry Standards 158 References 161 7 Physical Construction of Battery Packs 164 7.1 Single-Cell Battery Packs 165 7.1.1 Soldering of Cell Tabs 165 7.1.2 Routing of Battery Pack Wires 167 7.1.3 Cell Tab Insulation 168 7.1.4 Circuit Board Insulation and Mounting 169 7.1.5 Contaminants 170 7.2 Multicell Battery Packs 174 7.2.1 Routing of Voltage Sense Wires 174 7.2.2 Separation and Insulation of Solder Joints 175 7.2.3 Tab Placement and Spot Welding 175 7.3 Larger Battery Packs 176 7.3.1 Excessive Length of Voltage Sense Wires 176 7.3.2 Improper Wire Routing 177 7.3.3 Inadequate Insulation 178 7.3.4 Improper Torqueing of Screws 179 7.3.5 Cell Separation 180 References 181 8 Field Failures and Investigation Tools 182 8.1 The Scientific Method for Investigating Battery Failures 183 8.1.1 The Scientific Method 183 8.1.2 Applying the Scientific Method to Battery Failure Investigations 184 8.2 Analyzing Battery Failures 186 8.3 Battery Failure Root Cause Analysis: A Case Study 189 8.3.1 Background 189 8.3.2 Battery System Design 190 8.3.3 Visual Inspection and X-Ray Analysis 191 8.3.4 Battery Charger Circuit Review and Evaluation 192 8.3.5 Battery Protection Circuit Review and Evaluation 192 8.3.6 Likely Cause of Failure 193 8.3.7 Cell Construction Review 196 8.3.8 Summary 198 Appendix 8A Investigating Failures 198 Cause of Failures in Electrical Equipment 199 Overview of Tools Used when Conducting an Analysis of the Cause of the Failure 199 References 204 9 Checklists 206 9.1 Charger Checklist 207 9.2 Battery Checklist 207 Glossary 216 About the Authors 226 Lithium-ion,battery;,Consumer,electronics;,battery,failure;,Artech,House;,978-1-63081-603-2 Lithium-ion battery,Consumer electronics,battery failure,Artech House,978-1-63081-603-2