储能科学与技术 ›› 2023, Vol. 12 ›› Issue (4): 1278-1282.doi: 10.19799/j.cnki.2095-4239.2022.0716

• 储能测试与评价 • 上一篇    下一篇

阻抗分析法在锂离子电池析锂阈值检测中的应用

李奇松(), 陈荣, 李慧芳()   

  1. 天津力神新能源科技有限公司,天津 300384
  • 收稿日期:2022-12-02 修回日期:2022-12-26 出版日期:2023-04-05 发布日期:2023-05-08
  • 通讯作者: 李慧芳 E-mail:1723614011@qq.com;lihuifang@lishen.com.cn
  • 作者简介:李奇松(1996—),女,硕士,分析工程师,研究方向为锂离子电池分析技术,E-mail: 1723614011@qq.com

Application of impedance analysis in the detection of lithium evolution threshold of lithium-ion batteries

Qisong LI(), Rong CHEN, Huifang LI()   

  1. Tianjin Lishen New Energy Technology Co. , Ltd. , Tianjin 300384, China
  • Received:2022-12-02 Revised:2022-12-26 Online:2023-04-05 Published:2023-05-08
  • Contact: Huifang LI E-mail:1723614011@qq.com;lihuifang@lishen.com.cn

摘要:

本工作应用阻抗分析法对锂离子电池在不同温度及充电倍率下的析锂阈值进行检测。验证该方法可行性,与无损检测方法-弛豫电压分析法即dV/dt法进行对比分析。以电池充电过程中通过间歇式休眠获得的阻抗值作为分析数据,充电末期阻抗下降的拐点代表电池开始发生析锂,对应的电压及荷电态即为电池的析锂阈值。结果表明该阻抗分析法可以实现对电池析锂的无损检测,其结果与弛豫电压分析法一致,而且阻抗分析法不仅可准确判断电池是否发生析锂,而且可以测得电池开始发生析锂的阈值电压或荷电态,从而为充电制式优化提供依据。通过使用阻抗分析法对圆柱型三元电池、磷酸铁锂电池进行析锂阈值电压的检测,并结合不同温度和充电倍率对电池析锂边界进行了分析研究,结果表明对磷酸铁锂和镍钴铝三元电池来说,两种电池都在低温环境中极易发生析锂现象,而随温度的升高,电池发生析锂的阈值逐渐提高,析锂现象有所改善。而对镍钴铝三元电池,常温下增大倍率至0.6 C充电时,电池便开始发生析锂。说明以析锂阈值法对电池进行监测分析对后续电池充电策略的制定有着十分显著的作用。

关键词: 锂离子电池, 析锂阈值, 无损检测, 阻抗

Abstract:

In this paper, the impedance analysis method was used to detect the lithium evolution threshold of lithium-ion batteries at different temperatures and charging rates. Comparison test and analysis with the nondestructive testing method and relaxation voltage analysis method (dV/dt method) were conducted. The impedance value obtained through intermittent sleep during battery charging is taken as the analysis data. The inflection point of impedance decline at the end of charging represents the beginning of the lithium evolution of the battery. The corresponding voltage and state of charge are the lithium evolution threshold of the battery. The results show that the impedance analysis method can realize nondestructive detection of lithium evolution from batteries. The detection results of the method for lithium evolution from batteries are consistent with those of the relaxation voltage analysis method. The impedance analysis method accurately determines whether lithium evolution occurs in batteries and also measures the threshold voltage or the state of charge of the battery at which lithium evolution begins, thus providing a basis for the optimization of the charging system. By using impedance analysis method, this paper further uses this method to detect the lithium evolution threshold voltage of a cylindrical ternary battery and lithium iron phosphate battery. Here, the lithium evolution boundary of the battery in combination with different temperatures and charging rates are analyzed. The results show that lithium evolution easily occurs in the low-temperature environment for lithium iron phosphate and nickel cobalt aluminum ternary batteries, and the threshold of lithium evolution of the battery gradually increases with the increase in temperature. Thus, this improves the phenomenon of lithium precipitation. However, for the nickel-cobalt aluminum ternary battery, lithium begins to separate from the battery, when the rate is increased to 0.6 C at room temperature. Thus, the monitoring and analysis of the battery using the lithium evolution threshold method significantly affects the formulation of subsequent battery charging strategy.

Key words: lithiumion battery, lithium plating threshold, non destructive testing, impedance

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