Energy Storage Science and Technology ›› 2023, Vol. 12 ›› Issue (5): 1686-1694.doi: 10.19799/j.cnki.2095-4239.2023.0055

• Energy Storage Test: Methods and Evaluation • Previous Articles     Next Articles

Optimization of an impedance model for power Li-ion batteries based on a large multiplier current pulse

Xinyu LI(), Xuebing HAN(), Languang LU, Jianqiu LI, Minggao OUYANG   

  1. State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China
  • Received:2023-02-08 Revised:2023-03-08 Online:2023-05-05 Published:2023-05-29
  • Contact: Xuebing HAN E-mail:lixinyu22@mails.tsinghua.edu.cn;hanxuebing@mail.tsinghua.edu.cn

Abstract:

With the advancement of energy transition in China, using power batteries is rising yearly. The problem of battery safety has gradually come to the fore. In the battery management system (BMS), the equivalent circuit model (ECM) is the core of its work to ensure safe and stable operation. The current battery model in the BMS is mainly linear, which is limited by the computational volume and the computing power of the chip, which cannot reasonably and practically express the nonlinear characteristics of the battery under extreme operating conditions, such as high power. To address this problem, herein, from the perspective of available power, pulse discharge experiments are conducted on the battery at different multipliers to analyze the nonlinear characteristics of the internal resistance of the battery, improve the equivalent circuit model of the battery, and establish the variation of impedance with current under high multiplier conditions. The error of the improved impedance model is 1.74%, considerably smaller than the 8% of the old model. The results show an improved accuracy compared with the traditional equivalent circuit model, and the calculated computational volume is smaller than that of the P2D model, which is expected to be used in the online simulation calculation of the battery model in BMS to avoid over-power discharge of power batteries and improve the safety of battery use.

Key words: lithium ion battery, model parameters, battery impedance, impedance model optimization, rate characteristic experiment, active management

CLC Number: