[SY-J4] Two-way coupled modeling of lithium diffusion and diffusion induced finite elastoplastic bending of bilayer electrodes in lithium-ion batteries
Invited
A fully coupling model for diffusion induced finite elastoplastic bending of bilayer electrodes in lithium-ion batteries is proposed. The effect of mechanical stress on lithium diffusion is accounted for by the mechanical part of chemical potential derived from Gibbs free energy along with use of logarithmic stress and strain. Eight dimensionless parameters, which govern the stress-assisted diffusion and the diffusion induced elastoplastic bending, are identified. It is found that the finite plasticity starting from the interface of bilayer increases the chemical potential gradient and thereby facilitates lithium diffusion. The full plastic flow makes the abnormal lithium concentration distribution possible that the concentration at the lithium inlet is lower than the concentration at the interface (downstream). The increase in thickness of active layer during charging is much larger than the eigen-stretch due to lithiation, and this excess thickening is found to be caused by the lithiation induced plastic yield.