Multi-Scale Coupled Mechanical-Electrochemical Modeling For Study On Stress Generation And Its Impact On Multi-Layered Electrodes In Lithium-Ion Batteries

This study develops a physics-based mechanical-electrochemical coupled modeling framework to investigate the stress generation and its impact on cell performance. This framework is based on a multi-scale approach, from particle to cell level, and includes several layers of electrodes in lithium-ion batteries (LIBs). In LIBs, (de)intercalation-induced stress plays a significant role in battery performance and degradation; however, the key challenge is that its impact occurs across multiple scales. The model integrates particle-level volume expansion into cell-level deformation, stress, and electrochemical performances. The study reveals that the volume changes due to lithium intercalation generate significant stress, which can easily break the binder and in-between particles. Compared with the substantial stress generated from active particles, the external pressure is much smaller and has an insignificant influence on the cell performance. However, these external pressures decrease the total thickness of the multi-layered electrodes and their variation. Inhomogeneous current inputs were also applied between the electrode layers, which showed a considerable degradation of cell performance. The developed model captures the effects of external pressure, the number of electrode layers, and inhomogeneous current inputs on the electrochemical-mechanical behaviors, which are critical for battery design and management from the particle level to larger-scale battery structures. (c) 2021 Elsevier Ltd. All rights reserved.