Investigation of Change in EIS of Lead-acid Battery during the Water Loss

Interpreting Electrochemical Impedance Spectroscopy (EIS) data is challenging due to the complex chemical system in batteries and the lack of control over variables. The purpose of this paper is to examine how an individual ageing issue affects EIS. In this paper, the relationship between battery water loss and EIS change is investigated through a controllable experiment. In this experiment, a lead-acid battery is destructed and placed in an air-conditioned room, and the EIS is measured every three days, ensuring that the battery's degeneration is only due to water loss. Through the equivalent circuit model, the change of EIS is analyzed. The results show that the water loss has a different effect on the parameters in the equivalent circuit model (ECM): the internal resistance increases all the time, while the double-layer capacity drops rapidly at a certain amount of water loss. Meanwhile the turning point of parameter change can be used as the basis for judging the complete water loss of the battery.