A novel 2-RC equivalent model based on the self-discharge effect for accurate state-of-charge estimation of lithium-ion batteries.

Wang, Shunli; Cao, Jie; Xie, Yanxin; Gao, Haiying; Fernandez, Carlos

Abstract

Accurate lithium-ion battery state-of-charge estimation and effective equivalent modeling are important for real-time status monitoring and safety control of lithium-ion batteries. To solve the problem of low accuracy of the second-order RC equivalent model, based on a large number of experimental analyses on the ternary lithium-ion battery, the traditional second-order RC equivalent model was improved, and the self-discharge effect was incorporated into the equivalent model establishment. By measuring the change of the open-circuit voltage of the lithium-ion battery within 30 days in the resting state, the identification of the characteristic parameters of the self-discharge circuit is completed. The experimental results show that, compared with the traditional second-order RC equivalent model, the Self-Discharge-2-RC(SD-2-RC) equivalent model can better simulate the working state of the lithium-ion battery. The maximum error between the analog voltage and the real voltage is less than 0.03V, and its accuracy can be up to 99.3% or more. Based on the accurate establishment of the equivalent model, the Adaptive Extended Kalman filter algorithm is used to estimate the SOC. The algorithm has a fast convergence speed and a good tracking effect. The estimation accuracy can reach more than 96%, and the accurate estimation of the state of charge is realized. This research provides a theoretical basis for the establishment of a more accurate lithium-ion battery equivalent circuit model

Citation

WANG, S., CAO, J., XIE, Y., GAO, H. and FERNANDEZ, C. 2022. A novel 2-RC equivalent model based on the self-discharge effect for accurate state-of-charge estimation of lithium-ion batteries. International journal of electrochemical science [online], 17(7), article 22072. Available from: https://doi.org/10.20964/2022.07.60

• Journal Article Type: Article
• Acceptance Date: May 5, 2022
• Online Publication Date: Jun 6, 2022
• Publication Date: Jul 31, 2022
• Deposit Date: Jul 28, 2022
• Publicly Available Date: Jul 28, 2022
• Journal: International journal of electrochemical science
• Electronic ISSN: 1452-3981
• Publisher: Electrochemical Science Group
• Peer Reviewed: Peer Reviewed
• Volume: 17
• Issue: 7
• Article Number: 22072
• DOI: https://doi.org/10.20964/2022.07.60
• Keywords: Self-discharge effect; Self-discharge-2-RC equivalent model; Adaptive extended Kalman filter
• Public URL: https://rgu-repository.worktribe.com/output/1721589