A novel anisotropic model for multi-stage failure threshold of lithium-ion battery subjected to impact loading

Abstract

Most of the mechanical abuse to which lithium-ion batteries (LIBs) are subjected in real-life scenarios is dynamic, and the safety issues involved are cause for concern. An accurate dynamic failure threshold is needed for both safety assessment and engineering protection of LIBs. In this work, the dynamic mechanical response and external voltage behavior of 18650 cylindrical LIBs with various state of charge (SOC) values are investigated via drop weight tests firstly. Then, a novel anisotropic model, incorporating the SOC effects and damage settings, is developed. The model can well predict the mechanical behaviors of LIBs for both quasi-static loading and dynamic radial compression. In addition, a satisfactory consistency is achieved between the cracks formed within the battery and the micro-CT scanning results. Further, a two-stage failure criterion defined by the jellyroll equivalent plastic strain is proposed, based on two special failure modes of LIBs, namely electrochemical failure and structural failure. The failure threshold for LIBs with multiple SOCs is established at various impact masses and shapes. Results provide a high-fidelity computational model for the battery safety behaviors upon dynamic mechanical loading and guidelines for the design of next-generation robust batteries.