Dry-processed polyolefin film is currently the most widely-applied type of separators for commercial lithium-ion batteries. Its porous structure could undergo large deformation during normal charging–discharging cycles, affecting the mass transfer process through the electrolyte, and during mechanical abuse loadings, leading to the direct contact between the positive and the negative electrodes and the subsequent electrical short circuit. In this study, we investigate its deformation pattern experimentally via mechanical testing with post-mortem microscopic examinations, numerically via an image-based microstructural modeling technology, and theoretically via an analytical model based on the principle of minimum energy. The developed models and theories provide high-fidelity predictions of the deformation patterns under different conditions compared with the experimental observations.

目前，干法加工的聚烯烃薄膜是商用锂离子电池隔膜最广泛的应用类型。它的多孔结构可能会在正常的充放电循环中发生大变形，从而影响通过电解质的传质过程以及机械滥用负荷，从而导致正极和负极之间的直接接触以及随后的电气短路。在这项研究中，我们通过验尸后的机械测试，通过基于图像的微结构建模技术进行数值模拟，并在理论上通过基于最小能量原理的分析模型，来研究其变形模式。