Rapid Impedance Extraction for Lithium-Ion Battery by Integrating Power Spectrum and Frequency Property

Pseudorandom sequence (PRS) enables fast electrochemical impedance spectroscopy (EIS) measurement with multifrequencies superposition. One limitation is the low signal-to-noise ratio (SNR) and the interference among the broadband frequencies. In this thread, a delicate data processing procedure is an urgent requirement for EIS measurement with PRS. Motivated by this, a rapid impedance extraction method is proposed for lithium-ion (Li-ion) batteries in this work for EIS measurement, which integrates the power spectrum and frequency properties of the PRS excitation signal to the impedance measurement. All the intrinsic connections of the impedance, frequency, and power spectrum are utilized to form a novel fusion mechanism so that the battery impedance can be effectively extracted by an automatic selection procedure. Experimental validation on an 18650 Li-ion battery confirms the good performance of the proposed method at varying SOCs and temperatures.