Effects of technology parameters on stress in silicon-graphite based multilayer electrodes for lithium ion batteries

Abstract

Stress in a multilayer electrode for a lithium ion battery (LIB) generated by the insertion of lithium ions results in the mechanical degradation and failure of the electrode, as well as the deterioration of the electrochemical properties of the battery. In this paper, the effective deformation of a composite active layer caused by the distortion of active material in the electrochemical process was predicted as a function of state of charge (SOC). A general analytical solution of in-plane stress in a multilayer electrode for a LIB was derived with respect to the geometry parameters, material properties, and SOC. The effects produced by the thickness ratio of the current collector to the composite active layer, porosity of the composite active layer, and mass ratio of silicon to graphite on the variation and distribution of in-plane stress in both two-layered and symmetric three-layered silicon-graphite (SG) based electrodes were appraised and discussed. Based on the stress analysis, some optimized design strategies for SG based multilayer LIB electrodes are suggested.