• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2021, Vol. 57 ›› Issue (14): 64-76.doi: 10.3901/JME.2021.14.064

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Comparative Study on State of Power Estimation of Lithium Ion Battery Based on Equivalent Circuit Model

CAI Xue, ZHANG Caiping, ZHANG Linjing, ZHANG Weige, GAO Le   

  1. National Active Distribution Network Technology Research Center(NANTEC), Beijing Jiaotong University, Beijing 100044
  • Received:2020-08-31 Revised:2020-12-20 Online:2021-07-20 Published:2021-09-15

Abstract: State of power (SOP) estimation for lithium-ion batteries plays a vital role in the battery management system (BMS) of electric vehicles. The accurate parameterized model provides important parameter and structure information for SOP estimation. From the internal mechanism of the battery, the equivalent circuit model composed of equivalent elements and equations for characterizing the electrochemical reaction process is summarized, and its voltage simulation expression is derived. Aiming at the problem of falling into local optimum and computational efficiency due to uncertain parameter boundaries, a method for determining parameter boundaries based on electrochemical mechanism is proposed. Eight kinds of parameterized models are obtained by the parameter identification data, DST driving cycle, and from the model accuracy and calculation efficiency, the robustness and timeliness of the parameterized models are verified in FUDS driving cycle. To address the issues that the nonlinear model cannot obtain the peak power analytical solution, a multi-constrained SOP optimization estimation method is proposed. Finally, according to the true value of SOP obtained under DST + constant power tests, the effectiveness of the proposed algorithm is verified. The results show that temperature has a significant influence on the dominance of electrochemical reaction and diffusion limitation. The SOP estimation error of the proposed model's optimal estimation method in the high and low SOC range is within 8%.

Key words: lithium ion battery, equivalent circuit models, parameter boundary, parameter identification, peak power

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