We describe a multi-scale three-dimensional time-dependent contact model for the interface between Li and a solid electrolyte, with and without a SE-reinforced polymer interface coating. Our simulation without an interface coating considers the surface roughness of the Li and SEs, Li elastoplasticity, Li creep, and the Li metal plating/stripping process to predict the time-evolution during plating. When we also have an interface coating, we consider its viscoelasticity as well as the effect of the reinforcement on the polymer’s modulus and on its conductivity. Machine learning allows us to optimize values for thickness, stack pressure, and coating material properties (modulus, conductivity, etc). We describe the technique used to solve the multiscale problem.