Modeling Study of Lithium-ion Battery Below Room Temperature

The battery model is the basis for battery state estimation, and its accuracy will directly affect the accuracy of the estimate. In the field of rail transit, combined with the actual operating conditions of the train to properly allocate the battery capacity, it is also necessary to establish an accurate battery model. At present, the commonly used battery model less considers the influence of temperature on the model parameters[1]. Because of the extreme low temperature conditions during the actual running of the train, this paper uses lithium iron phosphate battery as the research object, based on the second-order equivalent circuit model of the battery[2]. At the same time, considering the influence of low temperature on the available capacity of the battery[3], open circuit voltage, ohmic internal resistance and polarization parameters, a battery model suitable for room temperature below is proposed[4].