Comparative Study on Fast Calculation Methods of Broadband Electrochemical Impedance Spectroscopy of Power Batteries

Electrochemical impedance spectroscopy (EIS) establishes the relationship with the internal electrode processes of the battery through the impedance of different frequencies. EIS can be used to estimate and diagnose the internal state of the battery, which has attracted more and more attention. For an on-board application or offline maintenance application, on the one hand, it is necessary to quickly grasp the EIS in the process of battery state change, on the other hand, it is necessary to shorten the maintenance time as much as possible. Therefore, improving the EIS measurement speed has become a key issue. The EIS measurement of general impedance measurement equipment often used in the laboratory takes a long time and cannot meet the needs of practical application. The difficulty of improving EIS measurement speed lies in finding an appropriate disturbing signal and efficient impedance calculation algorithm. Therefore, this paper compares and analyzes the performance of the different EIS fast calculation methods in dealing with different harmonic signals, and makes a comparative study on the aspects of error distribution and calculation speed. The results show that S-transform and sum-of-sines signals have more advantages in the fast and accurate calculation of EIS, which guides engineering applications.