A mechanism computational model of internal short circuit behaviors for lithium-ion batteries upon mechanical abusive loading

Mechanical failure of the separator is one of the most critical reasons to lead the internal short circuit (ISC), especially in mechanical abusive scenarios. To enable the understanding of the ISC mechanism triggered by separator failure, a detailed computational model based on anode-separator-cathode stack is established. In this model, the mechanical failure of the anode and cathode, are described in detail. To repeatedly and steadily trigger the ISC, a steel-ball indentation methodology is adopted. By comparison of the experiment and computational results, the ISC criteria based on the mechanical deformation of the separator are proposed. Further, three types of separators with various thicknesses are employed to validate the criteria and the proposed model. We discover that the equivalent strain defined by three principal strains can well serve as an intrinsic indicator to describe the onset of the ISC due to mechanical deformation of the separator. Results provide insights to unravel the detailed physical process of the ISC triggering and offer powerful computational modeling methodologies for the design and evaluation of next-generation batteries.