Research on Online Test of Fuel Cell Electrochemical Impedance Spectrum Based on Discrete Binary Sequence Signal

The measurement of fuel cell internal resistance is crucial for evaluating battery performance, improving efficiency, and developing production. In this paper, the impedance of the fuel cell internal resistance is measured using EIS technology. The pulse-perturbation current sequence is optimized by shortening the wide-spectrum pulse injection time and improving the signal-to-noise ratio of specific frequencies. The impedance spectrum is obtained by wavelet transformation of the time series, and the probability density function of the impedance spectrum is estimated by maximum likelihood method. Finally, high-precision real-time monitoring of the wide-spectrum impedance spectrum is achieved.