汽车工程 ›› 2022, Vol. 44 ›› Issue (4): 495-504.doi: 10.19562/j.chinasae.qcgc.2022.04.005

所属专题: 新能源汽车技术-动力电池&燃料电池2022年

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基于电化学热耦合模型的锂离子电池快充控制

孙涛1,郑侠1,郑岳久1,2,卢宇芳2,匡柯1,韩雪冰2()   

  1. 1.上海理工大学机械工程学院,上海  200093
    2.清华大学,汽车安全与节能国家重点实验室,北京  100084
  • 收稿日期:2021-10-09 修回日期:2021-11-29 出版日期:2022-04-25 发布日期:2022-04-22
  • 通讯作者: 韩雪冰 E-mail:hanxuebing@mail.tsinghua.edu.cn

Fast Charging Control of Lithium-ion Batteries Based on Electrochemical- thermal Coupling Model

Tao Sun1,Xia Zheng1,Yuejiu Zheng1,2,Yufang Lu2,Ke Kuang1,Xuebing Han2()   

  1. 1.School of Mechanical Engineering,University of Shanghai for Science and Technology,Shanghai  200093
    2.Tsinghua University,State Key Laboratory of Automotive Safety and Energy,Beijing  100084
  • Received:2021-10-09 Revised:2021-11-29 Online:2022-04-25 Published:2022-04-22
  • Contact: Xuebing Han E-mail:hanxuebing@mail.tsinghua.edu.cn

摘要:

现有的锂离子电池电化学机理模型,在快充控制过程中未考虑产热与化学反应之间的耦合关系,导致模型无法准确地描述电池内部的反应和状态。为进一步提高模型的预测能力,须在等温模型的基础上耦合产热模型,为此本文提出一种基于电化学热耦合的快充控制模型。首先将电化学热耦合模型参数进行分类,分析各种参数获取方式并进行精确测量和参数辨识。模型建立后,对模型精度进行验证的结果表明:在不同温度下,模型输出的端电压、负极电位和温度结果都达到了较高精度,说明模型适用于宽温度区间内的快充仿真。同时对模型中反应速率常数和环境温度参数进行了敏感性分析。之后,结合PID控制器对模型进行快充控制仿真,通过负极电位估计值实时调节并优化充电电流,实现了电池在宽温度区间内的无析锂快充电流仿真。最后,模型仿真结果与恒流充电对比验证表明,所提出的快充策略能使电池快速充电,同时避免析锂副反应的发生。

关键词: 锂离子电池, 参比电极, 负极电位, 电化学热耦合模型, 无析锂快充

Abstract:

The existing electrochemical mechanism models of lithium-ion batteries do not consider the coupling relationship between heat generation and chemical reactions in the fast charging control process. As a result, the model cannot accurately describe the internal reaction and state of the battery. In order to further enhance the predictive ability of the model, it is necessary to couple the heat generation model on the basis of isothermal model. Therefore, a fast charging control model based on electrochemical-thermal coupling is proposed in this paper. Firstly, the parameters of electrochemical-thermal coupling model are classified, various parameter acquisition methods are analyzed, and accurate measurement and parameter identification are performed. The model is built, with its accuracy verified. The results show that the results of terminal voltage, cathode potential and temperature output from the model achieve high accuracy under different thermal conditions, meaning the model is suitable for fast charging simulation in a wide range of temperature. Meanwhile, sensitivity analysis is carried out on the reaction rate constant and ambient temperature parameters in the model. Then, a fast charging control simulation is conducted on the model with PID controller, the charging current is adjusted real-time according to the estimated cathode potential, achieving fast charging current simulation without lithium plating in a wide range of temperature. Finally, the results of model simulation and the comparative verification of constant-current charging indicate that the fast charging strategy proposed enables fast charging of the battery while avoiding the side reaction of lithium deposition.

Key words: lithium-ion battery, reference electrode, cathode potential, electrochemical-thermal coupling model, fast charging without lithium plating