Simulation of Lithium Plating Due to Spatial Inhomogeneous Separator Strain in Lithium-Ion-Cells

The electrodes and especially the separator of a lithium-ion-cell are exposed to mechanical stress due to expansion of electrode materials during operation if the electrodes are integrated in a stiff cell casing e.g. in a 18650 cell. As a result, the porosity and therefore the lithium-diffusion characteristics are altered. In this paper a simulative study of spatially resolved effects from inhomogeneous separator porosity reduction induced by mechanical strain is presented. The findings show significantly changed spatial current densities and local anode voltage potentials that match findings of post-mortem investigations.