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

Journal of Power Sources, Volume 233, Pages 277-284, July 2013

Xu, Jun ; Mi, Chunting Chris ; Cao, Binggang ; Cao, Junyi

http://dx.doi.org/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.