Quantification of Combustion Hazards of Thermal Runaway Failures in Lithium-Ion Batteries 2014-01-1857

As lithium-ion cells and systems become larger and more ubiquitous in automotive applications, fire and explosion hazards that are rare or non-existent in smaller systems may exist in these larger systems. One potential hazard can occur when flammable gases emitted from a lithium-ion cell failure accumulate in or around automobiles and are ignited by electrical activity or by the cells themselves and result in a fire or explosion. In some instances, the safety aspects related to fires and explosions protection of electric vehicles and hybrid vehicles using these large energy storage battery packs are a significant challenge to address. This paper describes and characterizes the combustion and explosion hazards that can occur when a lithium ion battery pack fails and goes into thermal runaway in an enclosed space. Metrics such as gas composition, maximum overpressure, rate of pressure rise, and flammability limits are described. This information can be helpful to battery and pack designers, vehicle designers, first responders and emergency personnel in developing strategies to mitigate and prevent explosion hazards from the use of battery packs in automobiles and other fields where large battery packs are used. Measurements of this type can also be used to provide design guidance for containment enclosures and explosion venting or blow off panel design that can mitigate the hazard of combustible gases vented during failures in lithium ion cells and large battery packs.