A Fast Impedance Measurement Method for Lithium-Ion Battery Using Power Spectrum Property

Abstract

Electrochemical Impedance Spectroscopy (EIS) can provide fruitful information for Lithium-ion (Li-ion) battery modelling and diagnosis, yet EIS measurement is time-consuming with low-frequency signal injection. By stacking a group of broadband signals, Pseudo Random Sequence (PRS) makes it possible to obtain the battery EIS in a few seconds at the expense of measurement accuracy and Signal-to-Noise Ratio (SNR). Thus, this paper focuses on developing a highly effective signal processing procedure to extract useful information from the PRS for accurate EIS measurement. To enhance the ability of the data cleaning procedure, a three-dimensional cloud is firstly reconstructed for each impedance by integrating its Power Spectrum (PS). The impedance with lower PS can be easily removed through a statistical based multiple selection mechanism, which enables the extraction of the EIS without altering the original measurement. Experimental results on a 3000mAh Li-ion battery prove the effectiveness of the proposed method.

Fast Impedance Spectrum Construction for Lithium-Ion Batteries Using a Multi-Density Clustering Algorithm

“…In [29,30], the moving average filter (MAF) was used to smooth the impedance curve and reduce the measurement error, which was suitable for suppressing the noise in the middle and low-frequency ranges. The authors of [31,32] proposed an impedance denoising and filtering method using the power spectral density and frequency characteristics of PRBS to accurately extract the impedance in the full frequency interval [0.21 Hz, 3.5 kHz]. It was noticed that the impedance extraction method based on MAF had a large calculation error because it failed to effectively eliminate the measurement noise.…”

Review of electrochemical impedance spectroscopy methods for lithium-ion battery diagnostics and their limitations

“…Newly developed faster methods include the excitation of lithium-ion batteries using a multi-sine signal, whose response is then processed using fast-Fourier transform (FFT) or excitation of the battery using a Pseudo Random Sequence (PRS) [5].…”