Low frequency noise of electrochemical power sources

Terminal voltage fluctuation of lithium-sulfur cells and nickel-metal-hydride cells was measured in different time intervals since cell charging to full capacity. The power noise spectral density is of 1/f ^α type with exponent a varying in the range from 1 to 1.8. The main noise sources in charge storage systems are: i) fluctuation of potential barrier on the electrode-electrolyte interface (its height and width); ii) generation-recombination processes due to the chemical redox reactions, happening in the cell during its discharge. The state of health of each cell influences the noise spectral density shape and the rate of its decline. Further study of described behaviors may lead to development of reliable method for cell quality assessment.