Research progress of equivalent circuit models for SOC estimation of batteries in electric vehicles

Battery models play a very important role in the battery management system(BMS), especially in the estimation of state of charge(SOC). Among different kinds of models, equivalent circuit models are proved more practical and flexible. In this paper, the definition of SOC and influence factors are firstly discussed, and then some equivalent circuit models of batteries in EV will be reviewed, finally the possibilities for further progress in this area will be presented.