NON-INVASIVE METHOD OF DETERMINING THE ELECTRICAL IMPEDANCE OF A BATTERY

摘要

A non-invasive method and device for determining the electrical impedance of an electrochemical system for electric power is disclosed. The voltage and current are measured at terminals as a function of time, and these measurements are converted to signals dependent on frequency. The signals dependent on frequency are subjected to at least one segmentation. For each segment, a power spectral density of the current signal ΨI dependent on frequency and the cross power spectral density of the voltage and current signals ΨIV dependent on frequency are determined for each segment. The electrical impedance of the electrochemical system is determined by calculating a ratio dependent on frequency of a mean of the power spectral densities ΨI dependent on frequency to a mean of the cross power spectral densities ΨIV dependent on frequency.