储能科学与技术 ›› 2019, Vol. 8 ›› Issue (6): 1089-1095.doi: 10.12028/j.issn.2095-4239.2019.0098

• 锂电池失效分析与测试技术专刊 • 上一篇    下一篇

锂离子电池开路电压曲线形状与多阶段容量损失

葛昊1, 李哲1,2, 张剑波1,2   

  1. 1 清华大学汽车安全与节能国家重点实验室, 北京 100084;
    2 北京理工大学北京电动车辆协同创新中心, 北京 100081
  • 收稿日期:2019-05-21 修回日期:2019-06-25 出版日期:2019-11-01 发布日期:2019-11-01
  • 通讯作者: 张剑波,博士,教授,主要研究方向为燃料电池、锂离子电池,E-mail:jbzhang@mail.tsinghua.edu.cn。
  • 作者简介:葛昊(1990-),男,博士,助理研究员,主要研究方向为锂离子电池,E-mail:gehao@mail.tsinghua.edu.cn
  • 基金资助:
    国家重点研发计划项目（2018YFB0105903）。

Multi-stage capacity loss of lithium-ion batteries originating from the multi-slope nature of open circuit voltage curves

GE Hao1, LI Zhe1,2, ZHANG Jianbo1,2   

  1. 1 State Key Laboratory of Automotive Safety and Energy, Department of Automotive Engineering, Tsinghua University, Beijing 100084, China;
    2 Beijing Co-innovation Center for Electric Vehicles, Beijing Institute of Technology, Beijing 100081, China
  • Received:2019-05-21 Revised:2019-06-25 Online:2019-11-01 Published:2019-11-01

PDF

878

摘要： 锂离子电池老化过程中的多阶段容量损失，即由大致成线性的容量损失阶段突然变为急速下降的容量损失阶段，引起了人们越来越多的关注。我们发现这种多阶段容量损失特征可以由锂离子电池开路电压曲线的多段斜率形状引起。电池老化过程中的内阻增加，给定放电规程下的放电截止电压落到电池开路电压曲线的不同斜率区间，导致了不同的容量损失速率。为了解释这一现象，我们首先以一个两阶段的示例演示了此过程，然后，建立了一个通用的模型来模拟电池老化过程中的容量多阶段衰减，该模型考虑了电池正负极的开路电压曲线与内阻，可以引入多种材料体系、多种老化机理。本研究为锂离子电池老化行为研究提供了新的视角，可为锂离子电池全生命周期使用提供帮助。

关键词: 锂离子电池老化, 开路电压曲线形状, 多阶段, 容量突然衰减, 再利用

Abstract: An inflexion point during battery aging, turning the capacity retention curve from a gradually decreasing region into an abrupt drop, has been reported for a diversity of lithium-ion battery materials. Understandings such a multi-stage aging phenomenon are vital to lifespan design and cascade use of batteries, while they remain hitherto elusive. We unravel that the multi-stage aging behavior can result from the multi-slope nature of open-circuit-voltage (OCV) curve of batteries. Increasing kinetic polarization during aging renders the discharging process terminated in the OCV region with different slopes, leading to distinct aging profiles. In this work, we firstly demonstrate this basic idea using a two-stage example. Then, a general theory of inflexion point in battery aging considering both the positive and negative electrode is extended which is rather facile to incorporate major aging mechanisms and battery chemistries. This work provides new insights in understanding the multi-stage aging behavior, which can further contribute to the lifespan design and reuse of lithium-ion batteries.

Key words: lithium-ion battery aging, shape of open circuit voltage curve, multi-stage, abrupt capacity loss, reuse

中图分类号: