Revealing the internal short circuit mechanisms in lithium-ion batteries upon dynamic loading based on multiphysics simulation

Internal short circuit (ISC) of lithium-ion batteries (LIBs) would be triggered due. to inevitable electric vehicle collision, which pose serious threats to the safety and stability of the battery system. However, there is a lack of research on the ISC mechanism of LIBs under dynamic impact loadings. In this work, a coupled multi-physics model to describe the mechanical, electrical, and thermal response of LIBs under dynamic loading is established. The model can well predict the ISC and thermal runaway evolution process of LIBs with various SOCs under different impact energies. Four ISC modes are revealed through disassembling the LIBs after dynamic loading. Further, a strain-based ISC criterion is proposed to describe the triggering and voltage drop characteristics of each ISC mode. Subsequently, the mechanical-electrical-thermal behavior of LIBs in quasi-static and dynamic loading is compared and analyzed. Afterward, the triggering impact energy of four ISC modes for LIBs with different SOCs is concluded. The model proposed in this paper is currently based on small-sized batteries, and further study is required to extend its application to large-sized batteries.