Abstract: With the rapid development of the renewable and sustainable energy industry, lithium-ion batteries have been widely used as the electric energy storage media, but the fire safety issues have also become more serious. Battery disasters are essentially caused by internal heat release of side reactions, resulting in large amount of heat and combustible gases, which can further cause fire and explosion hazards. However, the evolution characteristics of thermal runaway are affected by many factors, which are mainly the internal state, structure of the battery and the external environment, and the differences of the evolution characteristics are significant under different conditions. This paper reviews the relevant research on the characteristics of battery thermal runaway under different internal/external factors, and key characteristics have been highlighted. Furthermore, research suggestions and prospects are proposed.

Key words: lithium?ion battery, battery pack, battery park thermal runaway, exothermic auxiliary reaction, state of charge