陶瓷涂层对隔膜针刺强度的影响机制研究

Study on the influence mechanism of ceramic coating on needle puncture strength of diaphragm

摘要

本研究系统探究了陶瓷涂布工艺对锂离子电池隔膜针刺强度的双向调控机制。通过对比分析9um基膜在不同工艺参数（温度/张力/时效）下的本征特性，结合不同厚度及单双面陶瓷涂层的摩擦学实验，首次揭示了涂层通过摩擦系数调控裂纹扩展路径的物理机制。实验结果表明：陶瓷层厚度与针刺强度呈中度负相关（R²=0.73），而摩擦系数与针刺强度呈现强正相关（Pearson系数>0.97）。本研究为动力电池隔膜的"强度-成本"协同优化提供了新的理论框架，确定了陶瓷涂层对隔膜针刺影响的真实原因。

Abstract

This study systematically investigates the bidirectional regulation mechanism of ceramic coating processes on lithium-ion battery separator puncture strength. Through comparative analysis of 9μm base films under different process parameters (temperature/tension/time), combined with tribological experiments on single and double-sided ceramic coatings of varying thicknesses, we have for the first time revealed the physical mechanism by which coatings regulate crack propagation paths through friction coefficient control. Experimental results demonstrate that ceramic layer thickness shows a moderate negative correlation with puncture strength (R²=0.73), while friction coefficient exhibits a strong positive correlation with puncture strength (Pearson coefficient > 0.97). This research provides a new theoretical framework for “strength-cost” synergistic optimization of power battery separators, clarifying the fundamental mechanisms underlying ceramic coatings’ impact on puncture resistance.

关键词

陶瓷涂层 / 锂离子电池隔膜 / 针刺强度 / 摩擦系数 / 裂纹扩展

Key words

ceramic coating / lithium ion battery separator / needle strength / friction coefficient / crack propagation

参考文献

[1] SNE Research. Global Power Battery Market Report 2023[R]. Seoul: SNE Research, 2023.

[2] CATL. Contemporary Amperex Technology Co. Limited Annual Report 2022[R]. Ningde: CATL, 2022.

[3] Zhang Y, Wang K, Li X, et al. Mechanical failure mechanisms of lithium-ion battery separators under compressive loading[J]. Journal of Power Sources, 2021, 482: 228936.

[4] Huang S, Chen Z, Wu L. Molecular disentanglement of polyethylene separators during ceramic coating process[J]. Polymer Degradation and Stability, 2020, 179: 109275.

[5] Wang J, Liu H, Zheng C. Interfacial energy enhancement in Al₂O₃-coated PE separators: A molecular dynamics study[J]. ACS Applied Materials & Interfaces, 2022, 14(8): 10721-10730.

[6] GB/T 31486-2015. Electrochemical performance test methods for lithium-ion battery separators[S]. Beijing: Standard Press of China, 2015.

[7] Massachusetts Institute of Technology. Comparative analysis of dry-process vs. wet-process ceramic-coated separators[R]. Cambridge: MIT Energy Initiative, 2021.

[8] Zhao L, Sun Y. Friction-induced crack deflection in ceramic-coated battery separators[J]. Tribology International, 2023, 178: 108063.