Uneven Electrolyte Distribution in Lithium-Ion Batteries: Investigating the Phenomenon and Mechanism of Negative Electrode Lithium Plating

Lithium-ion batteries are widely utilized across various industries; however, safety incidents stemming from manufacturing defects remain a recurring issue. Despite this, research on defects occurring during the battery manufacturing process remains relatively limited. In this study, we employ a pseudo-two-dimensional model (P2D) to investigate the secondary reactions of lithium insertion and stripping at the negative electrode. By simulating charge and discharge processes under different levels of wetting, we explore the uneven distribution of lithium plating resulting from inadequate wetting and delve into its underlying mechanisms. Our findings reveal that as the degree of defects increases, the risk of lithium plating at the negative electrode gradually escalates. This escalation can be attributed to the constrained speed of lithium-ion transport within the defective region, while the transport rate in the normal region remains unaffected. Consequently, this leads to disparate lithium-ion concentrations between the adequately wetted normal region and the insufficiently wetted defective region, exacerbating the non-uniform distribution of lithium ions and substantially elevating the risk of lithium plating. Our study not only enhances understanding of defect mechanisms in lithium-ion batteries but also provides theoretical insights for improving battery manufacturing quality.