储能科学与技术 ›› 2025, Vol. 14 ›› Issue (10): 4009-4019.doi: 10.19799/j.cnki.2095-4239.2025.0271

• 储能测试与评价 • 上一篇    下一篇

全固态锂金属电池力-电耦合膨胀行为机理

韩梦辉1,2(), 张华1(), 吴竞2, 孙新睿1,2   

  1. 1.安徽科技学院智能制造学院,安徽 滁州 239000
    2.东南大学机械工程学院,江苏 南京 210000
  • 收稿日期:2025-03-27 修回日期:2025-04-17 出版日期:2025-10-28 发布日期:2025-10-20
  • 通讯作者: 张华 E-mail:13004024413@163.com;chinafeihong@163.com
  • 作者简介:韩梦辉(2001—),男,硕士研究生,研究方向为全固态锂电池安全,E-mail:13004024413@163.com
  • 基金资助:
    安徽省科技特派员农业物质技术装备领域揭榜挂帅项目(2022296906020001);安徽省智能农机装备研究院建设协同创新项目(GXXT-2023-110);安徽省智能农机装备研究院建设协同创新项目(GXXT-2023-111)

Research on the mechanism of electro-mechanical coupling expansion behavior in all-solid-state lithium metal batteries

Menghui HAN1,2(), Hua ZHANG1(), Jing WU2, Xinrui SUN1,2   

  1. 1.College of Intelligent Manufacturing, Anhui Science and Technology University, Chuzhou 239000, Anhui, China
    2.School of Mechanical Engineering, Southeast University, Nanjing 210000, Jiangsu, China
  • Received:2025-03-27 Revised:2025-04-17 Online:2025-10-28 Published:2025-10-20
  • Contact: Hua ZHANG E-mail:13004024413@163.com;chinafeihong@163.com

摘要:

全固态锂金属电池(ASSLMBs)的膨胀行为引起其内部固-固界面失稳,是导致其循环稳定性差的主要原因之一。适当的堆叠压力可以增加ASSLMBs中电极与固态电解质(SE)之间的接触,显著提高电池结构完整性。然而,初始堆叠压力使得电池在充放电过程中的变形空间有限,而巨大的体积膨胀容易导致电池内部出现机械损伤。为此,建立了一个二维轴对称力-电耦合的均质电池模型,分别采用NCM811材料作为正极,Li6PS5Cl为固态电解质,锂金属为负极,将电池模型限制在充放电初始的空间内以探究调节电池内部影响膨胀应力的因素。结果表明,较低杨氏模量的正极能够明显缓解膨胀应力的增加,采用300 MPa杨氏模量的正极可以将电池在充放电过程中的最大膨胀应力降低为2.89 MPa,正极最大应力为12.5 MPa;改变锂金属负极的厚度(20~200 μm)可以将SE-负极界面处的锂沉积引起的巨大体积应变通过锂金属形变来减轻,使负极的体积应变有效降低,进一步减少充电过程中产生的膨胀应力。讨论结果有力地解释了影响电池充放电过程中内部膨胀应力产生的主要因素,并为下一代ASSLMBs的制造提供了良好且可行的设计方案。

关键词: 全固态锂电池, 电池膨胀, 力-电耦合, 多物理场模型, 负极体积应变

Abstract:

To address the instability of the internal solid-solid interfaces in all-solid-state lithium metal batteries caused by the expansion behavior, which leads to poor cyclability, this study examines the effect of the stack pressure on the electrode and solid electrolyte (SE) contact. A two-dimensional axisymmetric force–electric coupling homogeneous battery model was developed using NCM811, Li6PS5Cl, and lithium metal as the cathode, SE, and anode, respectively. The model was constrained to its initial state during the charge-discharge cycles to analyze the factors influencing the internal expansion forces. The results show that lowering the cathode's Young's modulus effectively mitigates the fluctuation in the expansion force. Specifically, a cathode with a Young's modulus of 300 MPa reduced the maximum expansion force to 2.89 MPa, with a peak stress of 12.5 MPa. Adjusting the lithium metal anode thickness (20—200 µm) helps alleviate the volume strain at the SE-anode interface by enabling the deformation of the lithium metal, thereby reducing the anode volume strain and charging-induced swelling stress. These findings highlight the key factors affecting the internal expansion forces and provide design strategies for improving the next-generation ASSLMB performance.

Key words: all-solid-state lithium metal batteries, battery expansion, electro-mechanical coupling, multiphysics model, anode volumetric strain

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