Multi-field interpretation of internal short circuit and thermal runaway behavior for lithium-ion batteries under mechanical abuse

Mechanical abuse-induced hazardous of lithium-ion batteries (LIBs), in which internal short circuits, thermal runaway, and mechanical failure can coincide and interact with each other, has become a critical issue that hinders the further application of LIBs. This study clarifies the bridging process from short circuit to thermal runaway for LIBs in complex mechanical abuse environment using a three-dimensional two-way coupled mechanical–electrochemical–thermal model. The developed model is verified by the two most common engineering scenarios including mechanical crushing and nail penetration. The complex structural damage–induced internal short circuit and thermal runaway behavior of LIBs are discussed. Moreover, the triggering mechanisms from internal short circuit to thermal runaway and the detailed exothermic reaction are revealed through model predictions. In particular, this study constructed a visual analysis framework of the coupled mechanical-electrochemical-thermal failure process for LIBs subjected to mechanical abuse. A model-based discussion of uneven lithium ions diffusion phenomenon is presented to interpret the electrochemical behavior of the battery caused by internal short circuit. The research results and the developed modeling method provide a robust tool for the mechanical abuse-safe design and evaluation of LIBs from a multi-disciplinary perspective.