Journal of South China University of Technology(Natural Science Edition) ›› 2023, Vol. 51 ›› Issue (1): 84-94.doi: 10.12141/j.issn.1000-565X.220050

Special Issue: 2023年交通运输工程

• Traffic & Transportation Engineering • Previous Articles     Next Articles

Online Joint Estimation of Main States of Lithium-Ion Battery Based on DAEKF Algorithm

LUO Yutao WU Zhiqiang   

  1. School of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou 510640,Guangdong,China
  • Received:2022-02-02 Online:2023-01-25 Published:2023-01-02
  • Contact: 罗玉涛(1972-),男,教授,博士生导师,主要从事新能源汽车和无人驾驶汽车研究。 E-mail:ctytluo@scut.edu.cn
  • About author:罗玉涛(1972-),男,教授,博士生导师,主要从事新能源汽车和无人驾驶汽车研究。
  • Supported by:
    MIIT Special Fund for High-Quality Development of Manufacturing Industry(R?2H?023?QT?001?20221009?001)

Abstract:

In order to realize the online joint estimation of three major states of ternary lithium-ion battery, namely SOC (State of charge), SOH (State of Health) and SOE (State of Energy), and to deal with the open-loop cumulative error caused by various noises in the actual use of electric vehicles, and, furthermore, to improve the stability of online estimation of lithium-ion battery, this paper proposed an online joint estimation method of the three major states of ternary lithium-ion battery in multiple time scales based on double adaptive extended Kalman filter (DAEKF). In the investigation, the state space equation of DAEKF algorithm is derived based on the second-order RC model, and the parameters are identified online by the recursive least square method with forgetting factor (FFRLS). The SOC and SOE of lithium-ion battery are estimated online in the micro time scale, and the SOH of lithium-ion battery is estimated online in the macro time scale. Thus, the online joint estimation of the three major states of lithium-ion battery can be realized. Finally, the proposed method was verified by experiments under different operating conditions of NVR18650B ternary lithium-ion battery. The experimental results show that the proposed method can rapidly converge the model parameters under the two verification conditions; that the estimation errors of SOC and SOE in the micro time scale are kept within 1%, and the estimation errors of SOH in the macro time scale are kept within 1.6%; and that, as compared with the EKF algorithm, the proposed method has a higher estimation accuracy and better estimation convergence and stability.

Key words: electric vehicle, lithium-ion battery, multi-state online joint estimation, double adaptive extended Kalman filter, multi-time scale

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