Electrochemical noise of a Li-ion battery: measurement and spectral analysis

Electrochemical noise of a Li-ion battery was measured during discharge at a constant value resistor. Power spectral density spectra calculations were applied for data analysis. Electrochemical impedance was also measured and analyzed at different states of charge of the tested battery. It was found that double layer capacitance exponent values obtained from impedance measurements cannot be used for direct modeling to describe the behavior of electrochemical noise spectra. But, Warburg diffusion element exponent values were found to be suitable for potential modeling. Load interrupt technique was used to measure electrochemical noise during relaxation pause after load cutoff. It was found that the absolute value of power spectral density slope is a little bit higher than at load during several minutes after load interruption. The slope magnitude decreases, and the level of spectrum gradually reduces during the relaxation. Electrochemical noise spectrum drops down to thermal noise level after the relaxation pause for several hours.