Fire Risk Tree and Its Gray Correlation Analysis of Recalled Electric Vehicles

New energy vehicles are still in the stage of development, and the fire and explosion accidents caused by thermal runaway are shocking. Many countries have recalled defective cars with safety concerns. At present, the special theoretical research on the thermal runaway and fire risk of recalled electric vehicles is still blank. This paper is not to conduct a routine field investigation and safety analysis of the spontaneous combustion and explosion accidents that have occurred in the process of car driving, but to make a theoretical exploration of the fire risk caused by the potential thermal runaway of the recalled vehicles. Collect the communique of China's recall of pure electric vehicles in the last four years, analyze the various thermal runaway and fire risk information disclosed in the bulletin. Explore the basic factors and the influence relationship of the potential thermal runaway of the vehicle, establish the fire risk tree of the electric vehicle, and determine the risk rate and the key importance of the risk mode. Risk tree analysis and gray correlation theory are applied to determine the correlation coefficient and correlation degree of various risk factors on thermal runaway. According to the gray correlation ranking of the basic events in a risk tree the weight and priority sequence of the risk factors is obtained, so as to provide a theoretical basis for accurately planning the strategies to resolve thermal runaway and fire risks, and focusing on taking measures to improve the safety of electric vehicles.