Sustainable Transportation Energy Pathways (STEPS), Plug-In Hybrid & Electric Vehicle Research Center
Available online at: DOI: 10.1002/9781118354179.auto065
Suggested Citation: A. Burke (2014) "Battery Safety for Lithium Batteries in Vehicle Applications" in D. Crolla, D.E. Foster, T. Kobayashi and N. Vaughan (Eds.) Encyclopedia of Automotive Engineering, John Wiley & Sons Ltd: Chichester. DOI: 10.1002/9781118354179.auto065. Published 4/22/2014.
In this chapter, various aspects of the safety of lithium-ion batteries of different chemistries have been reviewed based on information available in the literature as of early 2013. The primary safety concern is the possibility of encountering a thermal runaway condition unexpectedly during otherwise normal operation of the batteries. This concern has been evaluated both through study of the abuse testing of cells and through computer modeling of cell response to soft/hard shorts.
The abuse testing has shown that thermal runaway can be induced for all cells and chemistries under extreme conditions, but there are significant differences in the tendencies of the different chemistries to experience thermal runaway. Tests indicate that thermal runaway in almost all cases is preceded by a relatively long period (many minutes) of exothermic heating of cell. Under many conditions, the period of exothermic heating does not lead to thermal runaway. Thermal runaway is most likely with LiCoO2 cells and least likely with cells using Fe PO4 and Mn oxide cathodes and/or lithium titanate oxide anodes.
Computer simulations have shown that for all chemistries, there are combinations of the geometry and energy release through the “short” and heat loss from the cell, which will lead to thermal runaway. Even in the case of shorts, the simulations indicate a relatively long period of exothermic heating (gradual temperature increase) before a sudden thermal runaway event. Adequate heat loss (cooling) during the exothermic heating time is critical for mitigating thermal runaway.
Keywords: lithium batteries; safety; abuse testing; thermal runaway; soft short; calorimetry