Lithium-Ion Battery Safety Issues for Electric and Plug-In Hybrid Vehicles Disclaimers
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DOT HS 812 418 October 2017 Lithium-ion Battery Safety Issues for Electric and Plug-in Hybrid Vehicles Disclaimers This report is a work prepared for the United States Government by Battelle. In no event shall either the United States Government or Battelle have any responsibility or liability for any consequences of any use, misuse, inability to use, or reliance on any product, information, designs, or other data contained herein, nor does either warrant or otherwise represent in any way the utility, safety, accuracy, adequacy, efficacy, or applicability of the contents hereof. This publication is distributed by the U.S. Department of Transportation, National Highway Traffic Safety Administration, in the interest of information exchange. The opinions, findings, and conclusions expressed in this publication are those of the authors and not necessarily those of the Department of Transportation or the National Highway Traffic Safety Administration. The United States Government assumes no liability for its content or use thereof. If trade or manufacturers’ names or products are mentioned, it is because they are considered essential to the object of the publication and should not be construed as an endorsement. The United States Government does not endorse products or manufacturers. Suggested APA Format Citation: Stephens, D., Shawcross, P., Stout, G., Sullivan, E., Saunders, J., Risser, S., & Sayre, J. (2017, October). Lithium-ion battery safety issues for electric and plug-in hybrid vehicles (Report No. DOT HS 812 418). Washington, DC: National Highway Traffic Safety Administration. TECHNICAL REPORT DOCUMENTATION PAGE 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. DOT HS 812 418 4. Title and Subtitle 5. Report Date Lithium-ion Battery Safety Issues for Electric and Plug-in Hybrid October 2017 Vehicles 6. Performing Organization Code 000073889-0703 7. Authors 8. Performing Organization Report Stephens, D., Shawcross, P., Stout, G., Sullivan, E., Saunders, J., Risser, S., Sayre, J. 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Battelle 505 King Ave. 11. Contract or Grant No. Columbus, OH 43201 DTNH22-08-D-00085 Task Order 2 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered National Highway Traffic Safety Administration January 1,2011 to May 2013 1200 New Jersey Avenue SE. 14. Sponsoring Agency Code Washington, DC 20590 15. Supplementary Notes Phil Gorney and Barbara Hennessey (NHTSA CORs) 16. Abstract This report summarizes an assessment of potential lithium-ion (Li-ion) battery vehicle safety issues to provide NHTSA information it can use to assess needs and prioritize its future research activities on Li- ion battery vehicles. This analysis is intended to assist NHTSA in identifying potential critical operational safety issues it may want to consider and in assessing if further testing is needed to evaluate safety concerns. This document is the comprehensive final report for the project, compiling and summarizing the key background information and assessment of results developed. The scope of this investigation includes plug-in hybrid electric vehicles, hybrid-electric vehicles, and battery electric vehicles. This report reviews the literature for cell chemical and mechanical design and safety, battery architecture and design, vehicle systems relative to battery power, battery management and control systems, safety standards, and a survey of experimental, concept, prototype, and production-scale vehicles that employ Li-ion battery systems for propulsion. 17. Key Words 18. Distribution Statement Hybrid vehicle, battery electric vehicle, Lithium- No restrictions. This document is available to the ion, Li-ion, battery safety public through the National Technical Information Service, www.ntis.gov. 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 261 N/A Form DOT F 1700.7 Reproduction of completed page authorized. i Authors and Contributors: Brown, Vincent Dodaro, Cynthia Dodson, Clifford Glenn, Bradley Heywood, Timothy Linden, Corey Manning, Andrew J. (Consultant) Pape, Douglas Reuther, James Risser, Steven Rose, Susan Saunders, James Sayre, Jay Shawcross, Paul Slattery, Kathleen Somogye, Ryan Sowell, Garnell Stasik, Mark Stephens, Denny Stout, Gabe Sullivan, Edward Zimmer, Robert ii Table of Contents Page LIST OF ABBREVIATIONS ................................................................................................. XIII EXECUTIVE SUMMARY ....................................................................................................... XV Report Overview ............................................................................................................... xv Summary of Observations and Considerations ................................................................ xvi References ......................................................................................................................... xx 1 INTRODUCTION.......................................................................................................... 1-1 1.1 Project Objectives ................................................................................................ 1-1 1.2 Purpose, Overview, and Organization of this Document .................................... 1-2 2 LI-ION CELL ELECTROCHEMISTRY AND SAFETY PERFORMANCE ........ 2-1 2.1 Li-ion Cell Components ....................................................................................... 2-1 2.1.1 Cathode .................................................................................................... 2-3 2.1.2 Anode ....................................................................................................... 2-6 2.1.2.1 Solid electrolyte interface (SEI) Layer ...................................... 2-6 2.1.3 Electrolyte ................................................................................................ 2-7 2.1.3.1 Solvents ..................................................................................... 2-8 2.1.3.2 Salts ........................................................................................... 2-8 2.1.3.3 Electrolyte Additives ................................................................. 2-9 2.1.3.4 Li-ion Gel/Polymer Electrolyte ................................................. 2-9 2.1.3.5 Ionic Liquids .............................................................................. 2-9 2.1.4 Separator .................................................................................................. 2-9 2.2 Li-ion Cell Electrochemical General Characteristics and Performance Comparisons ...................................................................................................... 2-14 2.3 Li-ion Cell Electrochemical Degradation and Failure Mechanisms .................. 2-16 2.3.1 Cell Overcharge and Overdischarge ...................................................... 2-17 2.3.1.1 Cell Overcharge ....................................................................... 2-17 2.3.1.2 Cell Over-Discharge ................................................................ 2-18 2.3.2 Excessive Temperatures......................................................................... 2-18 2.3.2.1 Recharging Battery in Low Temperatures .............................. 2-18 2.3.2.2 Storing the Battery at Elevated Temperatures ......................... 2-18 2.3.3 Internal Short Circuit ............................................................................. 2-18 2.3.4 External Abuse ....................................................................................... 2-20 2.3.4.1 External Mechanical Abuse ..................................................... 2-20 2.3.4.2 External Short Circuit .............................................................. 2-20 2.3.5 Aging and Internal Mechanical Stress ................................................... 2-20 2.3.5.1 Other Sources of Internal Mechanical Stress .......................... 2-22 2.3.6 Damage Mechanics Perspective ............................................................ 2-22 2.4 Cell Electrochemical Failure Mitigation Methods ............................................. 2-23 2.5 Electrochemistry of Cell Thermal Runaway ...................................................... 2-24 2.6 Electrolytic Solvent Combustion Properties ...................................................... 2-28 2.7 Summary ............................................................................................................ 2-31 2.8 References .......................................................................................................... 2-31 iii 3 LI-ION CELL DESIGN AND SAFETY PERFORMANCE ..................................... 3-1 3.1 Cell Design and Construction .............................................................................. 3-1 3.1.1 Cylindrical Cells ...................................................................................... 3-1 3.1.2 Prismatic Cells ......................................................................................... 3-3 3.1.3 Pouch Cells .............................................................................................. 3-4 3.1.4 Large Format Cells .................................................................................. 3-5 3.2 Design Considerations ......................................................................................... 3-7 3.2.1 Thermal