【摘要】 为了探究多物理场耦合机制在锂离子电池容量衰减中的作用，构建了电化学-热-力三场耦合的锂离子电池多物理场模型，以圆柱电池为研究对象，揭示了电化学反应、热传导与机械应力之间的耦合机制及其对电池性能的影响。模型在0.5C、1C和1.5C放电倍率下通过实验验证，仿真结果与实测数据基本吻合。仿真分析得出：电池温度变化与衰退紧密相关：放电初期以欧姆热为主，后期反应热主导，温度分布呈现径向梯度，电化学产热引发温升，进而加速离子扩散与界面反应，形成电-热反馈；同时，负极锂离子的脱出，正极锂离子的嵌入导致电极颗粒体积变化，从而产生非均匀应力集中，诱发颗粒开裂与电极结构松动，形成热-力反馈。三者协同作用构成耦合失效机制，显著加剧活性材料损失与容量衰退。更多还原

【Abstract】 To explore the role of multi-physics coupling mechanisms in the capacity attenuation of lithium-ion batteries, a multi-physics model of lithium-ion batteries with the coupling of electrochemical-thermal and mechanical fields is constructed. Taking cylindrical batteries as the research object, it reveals the coupling mechanisms among electrochemical reactions, thermal conduction and mechanical stress and their influence on battery performance. Then, the model is experimentally verified at discharge rates of 0.5C, 1C and 1.5C, verifying that the simulation results are basically consistent with the measured data. The simulation analysis also reveals that the temperature variation of the battery is closely related to its degradation: in the early stage of discharge, ohmic heat is dominant, while in the later stage, reaction heat takes the lead. The temperature distribution shows a radial gradient, and the electrochemical heat generation causes the temperature to rise, which in turn accelerates ion diffusion and interface reactions, forming an electro-thermal feedback. Meanwhile, the deintercalation of lithium ions from the negative electrode and the intercalation of lithium ions into the positive electrode cause changes in the volume of electrode particles,thereby generating non-uniform stress concentration, inducing particle cracking and electrode structure loosening, and forming a thermomechanical feedback. The synergy of the three constitutes a coupled failure mechanism, significantly exacerbating the loss of active materials and capacity decline.更多还原