Detection of Lithium‐ion cells degradation through deconvolution of EIS with Distribution of Relaxation Time
Detection of Lithium‐ion cells degradation through deconvolution of EIS with Distribution of Relaxation Time
复制标题
通过 EIS 与弛豫时间分布的反卷积检测锂离子电池退化
DOI：
10.1002/ente.202200547
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发表时间：
2022
影响因子：
3.8
通讯作者：
Vanessa Wood
中科院分区：
文献类型：
--
作者：
Pietro Iurilli;C. Brivio;Vanessa Wood
本文介绍了一种研究商用圆柱形锂离子电池老化的方法。弛豫时间分布 (DRT) 方法应用于解卷积电化学阻抗谱 (EIS) 测量，并通过基于峰值的表示分离通常在频域中重叠的偏振效应。半电池在寿命开始和结束时构建，以将阳极和/或阴极侧发生的电化学和老化过程联系起来。此外，利用实验室制造的全电池来验证与圆柱形电池相比的再现性。对大约 500 个 EIS 谱进行广泛分析的结果返回了不同电化学过程对不同时间常数并最终对不同 DRT 峰的明确归因。数字成像验证石墨降解，主要与镀锂有关。扫描电子显微镜证实了 NMC 阴极的降解，主要归因于颗粒破裂。结论是，DRT 峰值可以表征细胞老化，对其跟踪可以帮助开发更可靠的健康状态估计器。
Herein, a methodology to investigate aging of commercial cylindrical Li‐ion cells is introduced. Distribution of relaxation time (DRT) method is applied to deconvolute electrochemical impedance spectroscopy (EIS) measurements and separate those polarization effects that are usually overlapped in the frequency domain by means of a peak‐based representation. Half‐cells are built at the beginning and end of life to link the electrochemical and aging processes occurring at anode and/or the cathode sides. Moreover, lab‐made full‐cells are exploited to verify the reproducibility when compared with cylindrical cells. The results of an extensive analysis of around 500 EIS spectra return an unambiguous attribution of different electrochemical processes to different time constants and ultimately to different DRT peaks. Digital imaging validates graphite degradation, mainly related to lithium plating. Scanning electron microscopy validates the degradation at NMC cathode, mainly attributed to particle cracking. It is concluded that DRT peaks allow to characterize cell aging and their tracking can help to develop more reliable state of health estimators.