Characterization of electric vehicle fires

摘要

Recent advances in battery technology have been critical in enabling the development and growth of the road-going electric vehicle fleet. However, understanding the safety aspects associated with electric vehicles is of paramount importance as (1) electric vehicle car fires, using new generation lithium-ion batteries, are not well characterized, and (2) the methods available to control these fires are not widely understood. Contrary to gasoline that generates the same amount of energy whether it is used in an engine or burned in a vehicle fire, a lithium-ion battery generates more energy when it fails and burns than it can store for driving purposes. One catastrophic failure mechanism that can lead to battery fires in vehicles is a thermal runaway event. In large, multi-cell packs such as those commonly used in electric vehicles, the heat generated by one failed cell can heat up neighboring cells and lead to a thermal cascade throughout the battery pack very quickly. Thermal runaway events result in the venting of flammable gases, and these gases can generate a fire or an overpressure event if ignited in a confined area.