Modeling Study for Li-ion Batteries Considering High-frequency Inductance Characteristics Based on Electrochemical Impedance Spectroscopy

As a non-destructive test method, electrochemical impedance spectroscopy (EIS) has been widely used in the analysis and diagnosis of Li-ion batteries in recent years. But the study of the high-frequency characteristics of Li-ion batteries is still not enough and the performance of Li-ion batteries at high frequency is not the same with that of the pure capacitance or pure inductance. Based on EIS, a fractional equivalent circuit model considering high-frequency inductance characteristics is established in frequencies from 10mHz to 10kHz in this paper. Then the model is verified and the parameters of the circuit are explored by using differential evolution (DE) algorithm and fractional-order numerical operations. Compared with the traditional equivalent circuit model, a fractional-order model based on EIS can not only describe the characteristics of the battery more comprehensively but also reduce the number of parameters because each component can simulate a certain physicochemical process of Li-ion batteries. The dominant process of the battery reaction is diverse in different frequency bands and therefore the structure of the developed model can be simplified accordingly. For the high-frequency inductive analysis of the battery, results show that the battery's 'inductance-like' phenomenon has a certain relationship with the frequency. This discovery might be implemented in a power electronic circuit to improve understanding of how batteries react to working condition of high-frequency.