Frequency domain monitoring of state of batteries via a piezoelectric element

Abstract

Systems and methods for implementing frequency domain techniques to determine acoustic changes in a battery via a piezoelectric element. In one aspect, a one-port piezoelectric network is formed by acoustically coupling a piezoelectric element to a battery. Impedance spectra of the one-port piezoelectric network are measured and correlated with the SoC and SoH of the battery. In another aspect, a two-port piezoelectric network is formed by acoustically coupling two piezoelectric elements to a battery. Ratio of voltages at the two piezoelectric elements of the two-port piezoelectric network are measured at different frequencies to generate voltage ratio spectra that are correlated with the SoC and SoH of the battery. Peaks in the impedance and voltage ratio spectra represent resonant modes of the battery that shift in frequency and/or amplitude based on the SoC and/or SoH of the battery. Reversible shifts correspond to the SoC and irreversible shifts to the SoH.

Dependencies are inferred from the claim text.