基于离散元法的锂电池极片辊压过程探究

doi:10.19799/j.cnki.2095-4239.2024.0110

储能科学与技术 ›› 2024, Vol. 13 ›› Issue (8): 2570-2579.doi: 10.19799/j.cnki.2095-4239.2024.0110

基于离散元法的锂电池极片辊压过程探究

杨凯悦¹(), 谢欣兵¹, 杜晓钟¹^,²()

^1.太原科技大学机械工程学院
^2.太原科技大学能源与材料工程学院，山西太原 030024

收稿日期:2024-02-04 修回日期:2024-03-06 出版日期:2024-08-28 发布日期:2024-08-15
通讯作者: 杜晓钟 E-mail:is_kaiyue@163.com;xiaozhong_d@163.com
作者简介:杨凯悦（1994—），男，博士研究生，研究方向为锂离子电池极片制备工艺，E-mail：is_kaiyue@163.com；
基金资助:
山西省自然科学基金项目(202103021224273);山西省国家留学基金项目(2021-137);山西省研究生教育创新项目(2020BY113)

Exploration of lithium battery electrode calendering process based on discrete element method

Kaiyue YANG¹(), Xinbing XIE¹, Xiaozhong DU¹^,²()

^1.School of Mechanical Engineering, Taiyuan University of Science and Technology
^2.School of Energy and Materials Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, Shanxi, China

Received:2024-02-04 Revised:2024-03-06 Online:2024-08-28 Published:2024-08-15
Contact: Xiaozhong DU E-mail:is_kaiyue@163.com;xiaozhong_d@163.com

摘要/Abstract

摘要：

随着“双碳目标”的提出，锂电池肩负了前所未有的降碳使命。辊压工艺是锂电池极片成形过程中的重要一环。它会对锂电池极片的微观结构及其力学性能产生重要影响，而极片微观结构及其力学性能又直接关系到锂电池的整体性能表现。因此，本研究特针对辊压工艺对锂电池极片微结构及其力学性能开展研究。考虑到锂电池极片并非单一均匀的物质，而是由各种形状和粒径的粉末颗粒复杂地堆叠、粘接、嵌合而成的异质性结构。本研究采用离散元法，并根据真实极片颗粒形状及粒径分布建立锂电池正极片模型，揭示辊压过程中极片变形的实质，探求极片微观结构及其力学性能变化规律。结果表明：随着辊压程度的均匀增加，极片孔隙率呈现出先线性减小，后缓慢减小的规律。极片密度是线性增大的；辊压会使得极片颗粒之间的配位数增加，并且活性材料镍钴锰酸锂(NCM)的配位数增大速度要大于黏结剂形成的胶相(carbon binder domain, CBD)；辊压还使得锂电池极片的内应力呈现类指数的增大规律，其中z方向的应力增大速度明显大于x、y方向应力增大速度。

关键词: 锂电池极片, 极片辊压, 离散元方法

Abstract:

With the introduction of the "Dual Carbon Goal," lithium batteries have taken on an unprecedented role in carbon reduction. The calendering process plays a vital role in shaping lithium battery electrodes, thus impacting their microstructure and mechanical properties, which significantly determine the overall battery performance. This study employs the discrete element method to investigate the impact of the calendering process on the microstructure and mechanical properties of lithium battery electrodes. The results show that as the calendering uniformity increases, the electrode porosity initially decreases linearly, and then it gradual decreases, deviating from a strictly linear pattern. The electrode density linearly increases, and calendering enhances the coordination between electrode particles. Furthermore, the internal stress in the lithium battery electrode increases exponentially during calendering, with the z-direction stress increasing faster than in the x- and y-directions.

Key words: lithium battery electrode, electrode calendaring, discrete element method

中图分类号:

TM 912

杨凯悦, 谢欣兵, 杜晓钟. 基于离散元法的锂电池极片辊压过程探究[J]. 储能科学与技术, 2024, 13(8): 2570-2579.

Kaiyue YANG, Xinbing XIE, Xiaozhong DU. Exploration of lithium battery electrode calendering process based on discrete element method[J]. Energy Storage Science and Technology, 2024, 13(8): 2570-2579.

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参考文献 20

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材料	参数	数值	单位
活性物质颗粒 (NCM)	杨氏模量	1.42×10¹¹	Pa
	密度	4.75	g/cm²
	泊松比	0.25
	静摩擦系数	0.25
	滚动摩擦系数	0.01
	弹性恢复系数	0.25

导电炭黑 (CB)	杨氏模量	4.5×10⁸	Pa
	密度	2.25	g/cm²
	泊松比	0.3
	静摩擦系数	0.25
	滚动摩擦系数	0.01
	弹性恢复系数	0.25

集流体 (铝)	杨氏模量	6.89×10¹⁰	Pa
	密度	2.7	g/cm²
	泊松比	0.25

压缩板	杨氏模量	1.82×10¹¹	Pa
	密度	7.8	g/cm²
	泊松比	0.3

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基于离散元法的锂电池极片辊压过程探究

Exploration of lithium battery electrode calendering process based on discrete element method

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