A novel fractional variable-order equivalent circuit model and parameter identification of electric vehicle Li-ion batteries

Qi Zhang; Yunlong Shang; Yan Li; Naxin Cui; Bin Duan; Chenghui Zhang

doi:10.1016/j.isatra.2019.08.004

A novel fractional variable-order equivalent circuit model and parameter identification of electric vehicle Li-ion batteries

ISA Trans. 2020 Feb:97:448-457. doi: 10.1016/j.isatra.2019.08.004. Epub 2019 Oct 1.

Authors

Qi Zhang¹, Yunlong Shang¹, Yan Li¹, Naxin Cui¹, Bin Duan¹, Chenghui Zhang²

Affiliations

¹ School of Control Science and Engineering, Shandong University, Jinan 250061, China.
² School of Control Science and Engineering, Shandong University, Jinan 250061, China. Electronic address: zchui@sdu.edu.cn.

PMID: 31653405
DOI: 10.1016/j.isatra.2019.08.004

Abstract

Accurate Li-ion battery modeling is integral to the design of effective battery management systems in electric vehicles. However, the voltage-current (U-I) characteristic of Li-ion batteries presents strong nonlinearity. The application of fractional-order models to create lower-order models to represent physical systems (e.g., the battery characteristics for the state of charge estimation) is interesting and timely. In this paper, a novel fractional variable-order equivalent circuit model (FVO-ECM) is proposed to represent the nonlinear U-I characteristic of Li-ion batteries; its parameter identification is achieved and verified by charge and discharge tests. Compared with the integral-order equivalent circuit model and the fractional constant-order model, the proposed FVO-ECM can identify battery nonlinear characteristics most accurately.

Keywords: Electric vehicle; Equivalent circuit model; Fractional variable-order; Li-ion batteries; Parameter identification.