储能科学与技术 ›› 2022, Vol. 11 ›› Issue (1): 53-59.doi: 10.19799/j.cnki.2095-4239.2021.0212

• 储能材料与器件 • 上一篇    下一篇

锂离子电池原位光学显微观测

高金辉1,2(), 陈英龙2, 孟繁慧2, 丁美超2, 王莉1, 许刚2, 何向明1()   

  1. 1.清华大学核能与新能源技术研究院，北京 100084
    2.天津力神电池股份有限公司，天津 300384
  • 收稿日期:2021-05-18 修回日期:2021-06-14 出版日期:2022-01-05 发布日期:2022-01-10
  • 通讯作者: 何向明 E-mail:gaojh20@mails.tsinghua.edu.cn;hexm@mail.tsinghua.edu.cn
  • 作者简介:高金辉（1985—），男，博士研究生，研究方向为锂离子电池，E-mail： gaojh20@mails.tsinghua.edu.cn|何向明，博士，研究员，主要研究方向为先进电池及其关键材料，E-mail： hexm@mail.tsinghua.edu.cn。
  • 基金资助:
    科技部国际合作项目(2019YFE0010200);科技部重点研发计划(2019YFA0705703);清华大学-佛山先进制造研究院基金(2019THFS0132);清华大学自主科研计划(2019Z02UTY06);天津市自然科学基金(20JCYBJC00690)

Research on in-situ optical microscopic observation in lithium-ion batteries

Jinhui GAO1,2(), Yinglong CHEN2, Fanhui MENG2, Meichao DING2, Li WANG1, Gang XU2, Xiangming HE1()   

  1. 1.Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
    2.Tianjin Lishen Battery Joint-Stock Co. Ltd. , Tianjin 300384, China
  • Received:2021-05-18 Revised:2021-06-14 Online:2022-01-05 Published:2022-01-10
  • Contact: Xiangming HE E-mail:gaojh20@mails.tsinghua.edu.cn;hexm@mail.tsinghua.edu.cn

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摘要：

原位光学显微装置越来越多地用于锂离子电池微观行为的观测。本文采用原位光学显微系统对软包装锂离子电池充放电过程中极片厚度和形貌变化进行了原位观测，采集了电压-电流曲线、极片厚度变化曲线和负极片形貌变化图像的同步测试数据，并以此研究了不同比例石墨/氧化亚硅复合负极嵌锂时的电化学及物理行为，随着氧化亚硅含量增加，极片满电厚度膨胀率增加，当氧化亚硅含量为12%时，满电极片的负极材料层与集流体发生脱离，与电池循环性能较差具有相关性；此外，本文还研究了不同充电电流对锂枝晶的影响，较小电流(0.05 C，电流密度0.2 mA/cm2)充电时，锂金属负极表面沉积较细的胡须状的锂枝晶，而较大电流(0.25 C，电流密度1.0 mA/cm2)充电时，则形成了较粗的树枝状锂枝晶。

关键词: 锂离子电池, 光学显微系统, 原位观测, 电化学反应过程, 锂枝晶

Abstract:

The in-situ optical microscopy equipment is increasingly used to observe the micro-behavior of the lithium ion batteries (LIBs). Herein, an in-situ optical microscopy system was used to observe the change of thicknesses and morphologies of the anodes during charging and discharging process for the pouch LIBs. The voltage-current curve, the thickness change of electrode and the morphological change of anodes were recorded simultaneously. The electrochemical and physical behavior of SiO/graphite composite anode with different ratio of SiO/graphite was studied. The thickness of fully charged anode increased as the content of SiO raised. When the percentage of SiO was raised to 12%, the anode material peeled off from the current collector,and it had a strong correlation with cycle performance of the cell. The lithium dendrite morphology at different charging and discharging rates was studied. When the charging current was small (0.05 C, 0.2 mA/cm2), whisker-like lithium dendrites were observed on the lithium metal electrode; the thicker branch-like lithium dendrites were observed when the charging current increased (0.25 C, 1.0 mA/cm2). The in-situ observation of macro-and micro-change of electrode morphology make the observation of the internal electrochemical process of batteries readily available, which will help people in the study of battery mechanism, failure analysis and battery modification.

Key words: lithium ion battery, optical microscopic system, in-situ observation, electrochemical reaction process, lithium dendrite

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