An equivalent circuit model analysis for the lithium-ion battery pack in pure electric vehicles

Abstract

According to the demand of vehicle lithium-ion battery pack, the splice equivalent circuit model is constructed. First, a joint experiment of intermittent discharge and hybrid power pulse characterization, basis of the requirements of parameter identification for the model, is designed to identify the parameters. Study shows that it can identify the parameters. Second, the splice equivalent circuit model of vehicle lithium-ion battery pack is simulated by MATLAB/Simulink, which shows the model is feasible to describe the vehicle lithium-ion battery pack. The simulation error of ohmic internal resistance R 0 should be less than 0.05 mΩ. Study suggests that the vehicle lithium-ion battery pack has a stable discharge period within the state-of-charge range of [20%, 80%]. However, when stage of charge is below 20%, vehicle lithium-ion battery pack is no longer stable and the parameters of the splice equivalent circuit model change dramatically.