Identification of battery circuit model from EIS data

The development of battery health monitoring systems is one of the main research topics related to electrical automotive applications. Some of the most promising approaches in this research area make use of equivalent circuit models, which can be derived from frequency response information of the battery. This work presents the main characteristics of the frequency response of a lithium-ion cell, and an equivalent circuit that can approximate it. The main equations that represent the impedance of the considered equivalent circuit are derived and implemented in Matlab. Theoretical battery impedance data, generated using the aforementioned implementation, can be used for parameters and state estimation algorithms testing. Finally a procedure for the fitting of the parameters in the introduced equivalent circuit is proposed and tested on experimental EIS data.