扩散应力诱导的锂离子电池失效机理研究进展

Progress on Failure Mechanism of Lithium Ion Battery Caused by Diffusion Induced Stress

在锂离子电池的充放电过程中,由锂离子扩散过程产生的浓度梯度和活性材料锂化膨胀产生的变形会导致扩散应力。过大的扩散应力会造成活性颗粒的破裂、活性颗粒之间的分离、活性层的断裂以及活性层与集流体的分层等多种力学失效形式,并最终导致电池出现容量衰减、阻抗上升和寿命缩短等一系列失效现象。因此扩散应力及其诱导的锂离子电池失效机理已经成为锂离子电池研究领域的热点之一,具有重要的理论研究意义和实际应用价值。本文尝试从活性颗粒、活性电极、半电池、电池单元和电池单体等不同尺度,综述近年来与扩散应力诱导的锂离子电池失效机理相关的研究进展,介绍各尺度下扩散应力的产生机制和研究手段,分析扩散应力对电池力学和电化学性能的影响规律,梳理和总结扩散应力的影响因素,最后对该领域今后的研究方向与发展趋势进行了展望。

During charge and discharge of lithium-ion battery,the concentration gradient produced by lithiumion diffusion process and deformation caused by lithiation expansion of the active material result in diffusion-induced stress.Excessive diffusion-induced stress can cause various mechanical failure modes such as cracking of active particles,separation between active particles,fracture of active layers,and delamination between active layers and current collectors,which eventually leads to a series of failure phenomena such as capacity attenuation,impedance rise and cycle life loss of the battery.Therefore,the diffusion-induced stress and the derived failure mechanism of lithium-ion battery become one of the research hotspots in the field of lithium-ion batteries,which has important theoretical and practical value.In this paper,research progress of the failure mechanism of lithium-ion battery caused by diffusion-induced stress in recent years is reviewed from different levels of the active particle,the active electrode,the half-cell,the cell unit,and the cell.The generation mechanism and research methods of diffusion-induced stress are introduced.The influence of diffusion-induced stress on the mechanical and electrochemical properties of the battery is analyzed,and the influencing factors of the diffusion-induced stress are summarized.Finally,the future research directions and development trends are prospected.