Researches on the Growth of Lithium Deposition in Lithium-Ion Batteries During Long-Term Cycling of Slight Overcharging

Abstract

In the entire life cycle of lithium-ion batteries, there may be long-term cycling of overcharging conditions. Therefore, a high-fidelity model that is analyzed for the physical characteristics of lithium-ion batteries during long-term cycling of overcharging conditions is required. Based on the pseudo-2D (P2D) model, a P2D with a variable solid-phase diffusion coefficient electrochemical model is built. This model is used to study the changes in the physical properties of automotive lithium-ion batteries, including the relative capacity, the generation of lithium metal deposition, and solid electrolyte interface (SEI) film. The SEI film and lithium deposition of lithium-ion batteries have been analyzed under different charge/discharge rates and values of overcharge conditions. It is found that the lithium plating is influenced by both the overcharged value and the charging current rate. Lithium metal deposition has a greater impact on the capacity fading of batteries than the generation of SEI films. There is competition between the generation of SEI films and that of the lithium metal deposition process, and lithium metal deposition inhibits the generation of SEI films. The lithium dendrite and SEI films always grow in parallel coupling.