Modeling current density and SoC distribution of all-solid-state lithium-ion batteries

Researchers have conducted in-depth investigations into lithium-ion battery models. However, a notable limitation of existing models lies in the assumption of infinitely conductive current collectors, which compromises simulation accuracy. Herein, we present a model that explicitly accounts for current collector resistance, employing Kirchhoff's circuit laws and a suitable discretization method to characterize the associated current density and SoC distribution in all-solid-state thin-film batteries. Simulation results demonstrate that the highest SoC occurs near the charging tab, leading to preferential full-charge in this region. Intriguingly, when charging is interrupted at this stage, the battery enters a self-balancing state: the state of charge SoC near the tab gradually decreases. At the same time, SoC in other regions increases, culminating in a homogeneous SoC across the entire battery. This phenomenon reflects the underlying process of lithium-ion redistribution. Additionally, a larger resistance disparity between cathodic and anodic current collectors creates an inhomogeneous current density distribution, thereby accelerating localized battery aging. The approach adopted by our model exhibits broad generality and can be readily adapted to other battery types.