Comprehensively analysis the failure evolution and safety evaluation of automotive lithium ion battery

In response to environmental pollution and the energy crisis, the number of electric vehicles (EV) has increased year by year. However, frequent EV accidents have pushed the safety of EVs to a new height of attention. The failure of lithium-ion batteries (LIBs) is the root of most accidents. Although many standards have been made, the battery system's safety still lacks scientific, comprehensive, and quantifiable assessment. Here, we innovatively put forward a comprehensive map of LIBs failure evolution combining battery tests and forward development. By analyzing the root cause of the EV fire through the Fault Tree Analysis (FTA), 20 basic events, 26 minimum cut sets, and 29 battery tests related to the accident were obtained. The result indicates that the low thermal stability materials and battery management system (BMS) failure to warn in time are the most important factors leading to EV fire. According to the test content, the battery tests are classified, and the Analytic Hierarchy Process (AHP) model of the battery test is established. By comparing the importance of every two tests with the judgment matrix, the weights of battery tests are obtained. Finally, combining with the fault tree branch structure, comprehensive forward development suggestions are put forward to improve the safety of EV.