Thermal and diffusion induced stresses in a structural battery under galvanostatic cycling

When charging or discharging a structural battery composite heat will be generated and the active electrode materials will expand or shrink, inducing internal stresses within the material. These stresses may cause mechanical and/or electrical failure. It is therefore crucial to be able to predict the stress state when evaluating the performance of the material. In this paper, a semi-analytical framework to predict the thermal and diffusion induced stresses in a structural battery under galvanostatic cycling is presented. The proposed model is a concentric cylinder (CC) model coupled with an axisymmetric diffusion model and a one-dimensional heat generation model. The present study shows that the heat generated during electrochemical cycling must be accounted for when evaluating the internal stress state in structural battery composites. Furthermore, the results show that the charge/discharge current, lamina dimensions and residual stresses have significant effect on the internal stress state and effective properties of the composite lamina.