A thermodynamically consistent formulation for solid-state batteries at finite strains

This work presents a thermodynamically consistent model for all-solid-state lithium-ion batteries (ASSBs), formulated within the framework of coupled electro-chemo-mechanics of continua at finite strains. A distinctive feature of the model is the inclusion of a dual conduction mechanism within the solid electrolyte. The formulation is sufficiently general to capture the inelastic response of electrodes, whether metallic (as in viscoplastic lithium foil anodes) or porous. The mechanical behaviour of ASSBs is investigated under galvanostatic discharge conditions, accounting for both the stripping of the lithium foil—here replicated by tailored boundary conditions—and the shrinking of the porous cathode. The governing equations have been implemented in a commercial finite-element code. Numerical simulations reveal the influence of individual components on the overall cell response, identify limiting factors during charge and discharge cycles and support the optimization of cell design.