Determination of the charge and discharge modes duration effect on the LiFePO4 cells resource in the electric power source

Abstract

The paper is devoted to the determination of the resource of LiFePO4 battery cells when they are used as a primary source of energy in an electric vehicle. The analysis of the WLTC driving cycle from the point of view of the currents arising in the battery of an electric vehicle was carried out, its main parameters were revealed, such as: the duration and magnitude of the charge and discharge currents and the duration of the pause. The results of experiments on determining the resource of an 18650 cell at various load cycles are presented. It was found that cells loaded with a low current with a high switching frequency of the operating mode are subject to the greatest degradation. The lowest degradation rate was observed in cells loaded with low current with short-term charging modes. The result obtained will make it possible to more accurately determine the remaining life of the battery cells. Also, the data can be used to improve the algorithms of the BMS in order to extend the battery life.