Time Domain Impedance Parameters Identification Using Fractional Modeling Applied to Li-ion Batteries

Identification in time domain represents an accurate alternative technique for the Electrochemical Impedance Spectroscopy (EIS) measurements that requires long measurement time to characterize low frequency behavior. This paper focuses on the parameter identification of a Li-ion cell fractional model using measurements in time domain. The fractional model is based on an Equivalent Circuit Model (ECM) and is derived from the simplified Randles model. The parameters of the impedance fractional model are identified using Levenberg-Marquardt optimization algorithm. Results are validated in time domain using simulation data and experimental data obtained from chronopotentiometry experiments performed on a 3.4 Ah Li-ion cell. Experiments are carried out at different States Of Charge (SOC) and show the interest and the relevance of the employed methodology.