In this paper, we investigated the possibility of determining the internal resistance of the battery by pulsed method with followed Fourier transformation in transition characteristics. The changes of internal resistance of lithium sulfur cells were studied in dependence on the discharge and charge depths during continuous cycling by proposed method. It was shown that the internal resistance of lithium sulfur cell was maximal at the point corresponding to the transition between high-voltage and low-voltage plateaus both at the charge curves and at the discharge curves. The most significant increase in the internal resistance of lithium sulfur cells occurs at the initial stages of cycling. It was found that the internal resistance of lithium sulphur cell is governed by the way the state of charge is achieved. This is due to the difference in densities of products, generated in positive electrodes by electrochemical reactions at charge (ρ(S) = 2.07 g/cm3) and discharge (ρ(Li2S) = 1.63 g/cm3).
English
Русский