Fire Safety of Battery Electric Vehicles: Hazard Identification, Detection, and Mitigation

Battery electric vehicles (EVs) bring significant benefits in reducing the carbon footprint of fossil fuels and new opportunities for adopting renewable energy. Because of their high-energy density and long cycle life, lithium-ion batteries (LIBs) are dominating the battery market, and the consumer demand for LIB-powered EVs is expected to continue to boom in the next decade. However, the chemistry used in LIBs is still vulnerable to experiencing thermal runaway, especially in harsh working conditions. Furthermore, as LIB technology moves to larger scales of power and energy, the safety issues turn out to be the most intolerable pain point of its application in EVs. Its failure could result in the release of toxic gases, fire, and even explosions, causing catastrophic damage to life and property. Vehicle fires are an often-overlooked part of the fire problem. Fire protection and EV safety fall into different disciplines. To bridge the gap between these two disciplines and summarize the state-of-the-art knowledge of fire safety issues of EVs, this review article will provide a comprehensive overview of their fire hazard identification, detection, and mitigation strategies. This article also highlights the failure mechanisms of LIBs in EVs, which establish the basis for understanding the LIB fire safety issues in EVs. The aim of this review article is to provide a general and basic understanding of the fire hazards of EVs from different scales to both engineers and researchers. This review article can also be used as educational material for the public and emergency responders to increase their awareness of the fire safety of modern EVs.