Abstract:In this study, a lithium-ion soft-pack battery used in an electric vehicle was taken as the research object. Based on the actual working condition of the traction battery, the regularity of the evolution of the overcharge thermal runaway experiment of the sample was deeply analyzed by taking the charging rate and the ambient temperature as variables. The results showed that the larger the overcharge current was and the higher the ambient temperature was, the lower the overcharge thermal stability of the battery was. Furthermore, based on the concept of the introduction of battery energy during charging, by analyzing the total amount of energy input and the rate of energy input, a unified index was established to measure the change of the battery overcharging stability under different experimental conditions.

Key words: lithium-ion battery, overcharge, thermal runaway, safety, energy input, batteries, electrochemical storage