储能科学与技术 ›› 2024, Vol. 13 ›› Issue (4): 1154-1158.doi: 10.19799/j.cnki.2095-4239.2023.0897

• 电池智能制造、在线监测与原位分析专刊 • 上一篇    下一篇

陶瓷隔膜对锂离子电池热失控影响及电池设计优化分析

茆志友1,2(), 宁小玉1,2, 张培培1,2, 张贝1,2, 相佳媛1,2   

  1. 1.浙江南都电源动力股份有限公司，浙江 杭州 310012
    2.浙江南都鸿芯动力科技有限公司，浙江 杭州 311103
  • 收稿日期:2023-12-12 修回日期:2024-01-25 出版日期:2024-04-26 发布日期:2024-04-22
  • 通讯作者: 茆志友 E-mail:maozy@naradapower.com
  • 作者简介:茆志友（1989—），男，硕士，主要从事锂离子电池研发和工艺开发工作，E-mail：maozy@naradapower.com。

Effect of separators on thermal runaway performance for Li-ion battery

Zhiyou MAO1,2(), Xiaoyu NING1,2, Peipei ZHANG1,2, Bei ZHANG1,2, Jiayuan XIANG1,2   

  1. 1.Zhejiang Narada Power Source Co. , Ltd. , Hangzhou 310012, Zhejiang, China
    2.Zhejiang Narada Hongxin Power Technology Co. , Ltd. , Hangzhou 311103, Zhejiang, China
  • Received:2023-12-12 Revised:2024-01-25 Online:2024-04-26 Published:2024-04-22
  • Contact: Zhiyou MAO E-mail:maozy@naradapower.com

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摘要：

本文主要研究了以聚乙烯（PE）材质为基膜、陶瓷为涂层的五种不同厚度及双面涂层的复合隔膜的表面形态、拉伸强度、穿刺强度等性能。并选择其中三款隔膜制成大容量铝壳电池进行热失控试验。研究发现，不同涂覆厚度的陶瓷涂层隔膜表面涂层致密，颗粒粒径分布范围较宽，形貌、大小相近；拉伸强度及穿刺强度方面，基膜为12 μm的陶瓷隔膜不同涂覆厚度没有明显差异，并且同等厚度基膜单面涂覆和双面涂覆无明显差异；相同测试条件下，隔膜的热收缩率是（12+2+2）μm、（12+1.5+1.5）μm＜（12+4）μm＜（12+3）μm＜（12+2）μm。采用（12+2）μm、（12+4）μm隔膜生产的电池测试发生热失控时的SOC分别为116.94%、117.64%，电池最高温度分别为530.9 ℃、430.7 ℃。实验表明陶瓷涂层厚度越大电池发生热失控的时间越迟，最高温度越低。此外，双面涂层隔膜（12+2+2）μm制成的电池发生热失控是在过充结束后的加热工步，最高温度仅为369.5 ℃。针对实验所产生的现象进行了分析，对电池的设计优化方向做了一些思考，指出了隔膜宽度方向超出负极极片、负极极片长度和宽度方向超出正极极片之外的部分（Overhang）的设计对于电池的安全是极其重要的，电池在设计时需要充分评估使用场景和极端条件的影响，结合选择的隔膜的热收缩率的大小，核算隔膜的收缩比例，确保Overhang的设计是满足电池全寿命周期安全需求。

关键词: 陶瓷隔膜, 拉伸强度, 穿刺强度, 热失控, 设计优化

Abstract:

This study investigates the surface morphology, tensile strength, puncture resistance, and additional properties of polyethylene (PE)-based separators with varying thicknesses and double-sided ceramic coatings. Among these, three were chosen for constructing high-capacity prismatic batteries to conduct thermal runaway tests. The findings indicate that ceramic coatings of different thicknesses exhibit a dense surface, a broad particle size distribution, and similar morphological characteristics. The tensile and puncture strengths of the ceramic-coated separators, all based on a 12 μm PE film, showed no significant variance across different coating thicknesses or between single-and double-coated films of the same thickness. Under identical testing conditions, the thermal shrinkage rates of the separators were observed in the order: (12+2+2) μm, (12+1.5+1.5) μm<(12+4) μm<(12+3) μm<(12+2) μm. The state of charge at which thermal runaway occurred for batteries using (12+2) μm and (12+4) μm separators were 116.94% and 117.64%, with peak temperatures reaching 530.9 ℃ and 430.7 ℃, respectively. The experiments demonstrate that an increase in ceramic coating thickness delays thermal runaway and reduces peak temperatures. Furthermore, the battery constructed with the (12+2+2) μm double-coated separator experienced thermal runaway during the heating phase postovercharge, reaching a maximum temperature of only 369.5 ℃. An analysis of the experimental outcomes offers insights into battery design optimization, highlighting the critical nature of designing the overhang-where the separator's width exceeds that of the negative electrode, and the dimensions of the negative electrode surpass those of the positive electrode-for battery safety. Comprehensive evaluation of usage scenarios and extreme conditions is essential in battery design, taking into account the thermal shrinkage rates of chosen separators to calculate the contraction ratio, thereby ensuring the overhang design meets safety standards throughout the battery's lifecycle.

Key words: ceramic coated separator, tensile strength, puncture strength, thermal runaway, design optimization

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