Lithium Plating at the Cell Edge Induced by Anode Overhang during Cycling in Lithium-Ion Batteries: Part II. Simulation and Experimental Validation

In Part I of this work, it was shown that a two-dimensional Doyle-Fuller-Newman (DFN) model can predict inhomogeneous lithium plating during cycling caused by anode overhang. This indicates an increased risk of lithium plating at the cell edge. In Part II, the same model is used to simulate defined cycling conditions of real cells to experimentally validate the proposed model and the edge plating mechanism. The cells used for this purpose are single-layer pouch (SLP) cells instrumented with several spatially distributed gold wire micro-reference electrodes, enabling the measurement of local electrolyte potentials. First, the simulation indicates a significantly inhomogeneous potential distribution during 500-hour potentiostatic storage before the actual study, which is also observed in the local potential measurements of the real cells. Second, the cells are slowly discharged and then fast charged. Consequently, lower local anode potentials are observed near the edge compared to the center, which is consistent with the simulation results. Finally, the predicted and measured lithium plating near the anode edge is cross-validated by visual inspection in post-mortem analyses. The results are particularly relevant for optimizing cell design and operating strategies, as they demonstrate the relevance of considering previous operation during fast charging to avoid inhomogeneous degradation.