A new method to estimate the state of charge of lithium-ion batteries based on the battery impedance model

• Published in: Journal of power sources 2013-07, Vol.233, p.277-284
• Main Authors: Xu, Jun, Mi, Chunting Chris, Cao, Binggang, Cao, Junyi
• Format: Article
• Language: English
• Subjects: Applied sciences; Charge; Direct energy conversion and energy accumulation; Electric batteries; Electric vehicle; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical impedance spectroscopy; Estimates; Exact sciences and technology; Fractional Kalman filter; Fractional order calculus (FOC); Ground, air and sea transportation, marine construction; Impedance; Impedance model; Lithium ion battery; Lithium-ion batteries; Mathematical analysis; Road transportation and traffic; Spectra; State of charge
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.01.094

This paper deals with the problem of estimating the state of charge (SOC) of lithium-ion batteries. Based on the analysis of the impedance spectra obtained by electrochemical impedance spectroscopy (EIS), a simplified battery impedance model is derived with the constant phase element (CPE). To interpret the impedance model, a fractional order calculus (FOC) method is introduced to model the CPE in the impedance model. A new identification method is proposed to identify the impedance model, considering both accuracy and simplicity. The fractional Kalman filter is introduced to estimate the SOC of the lithium-ion battery based on the impedance model. Finally, a battery test bench is established, and the proposed method is verified by a scaled down system on the urban dynamometer driving schedule (UDDS) drive cycle test. ► Derived a simplified lithium ion battery impedance model based on impedance spectra. ► The model can maintain accuracy but is more concise and easier to implement. ► Fractional modeling method is introduced to model the CPE of the impedance model. ► Proposed a new method to identify the impedance model. ► Fractional Kalman filter is introduced to estimate the states such as SOC.