Abnormal lithium plating in the electrode edges at low N/P ratios in lithium-ion batteries

Although Li-ion batteries (LIBs) are known for their excellent stability, there have been significant instances of fire accidents in electric vehicles. These incidents are caused by internal short circuits arising from the formation of lithium (Li) dendrites on the graphite anodes. Among the various factors affecting the safety of LIBs, the misalignment of electrodes emerges as a particularly critical cause. In this study, we comprehensively investigate the edge effect of electrodes in LIBs by comparing three distinct edge situations: A > C, A = C, and A < C cases. Contrary to the convention that a larger anode compared to the cathode (referred to as the A > C case) is always beneficial for stability and performance, the A > C case causes non-uniform lithiation and a considerably higher occurrence of Li plating compared to the A = C case due to the edge effect. This study provides useful insights on the edge effect of electrodes from a commercial perspective.