Study on the impact of driving styles on EV battery pack SOC inconsistency based on real urban driving data

Abstract

The SOC inconsistency among battery cells affects the available capacity, power output, lifespan, and safety of battery packs. Therefore, analyzing SOC inconsistency is essential. Since different driving styles involve significant variations in acceleration and braking behaviors, they influence the magnitude and frequency of charging and discharging currents, thereby intensifying inconsistency. To investigate the impact of driving style differences on battery pack SOC inconsistency, this study first conducted real-vehicle experiments, collecting 66 sets of electric vehicle driving data representing various driving styles. Then, a battery pack model was established, with the current data collected from real-vehicle experiments used as input for simulation. Based on the charge-discharge current magnitude and charging frequency under different driving styles, the impact of driving behavior on battery pack inconsistency was further analyzed. In addition, dynamic inconsistency metrics were proposed to describe the temporal evolution of parameter inconsistency within the battery pack. Results show that due to differences in driving conditions, the battery pack experiences varying current magnitudes and charging frequencies, leading to different levels of SOC inconsistency. Moreover, the influence of driving styles on SOC inconsistency varies with initial state of the battery pack: under inconsistent Coulomb efficiency and self-discharge rates, aggressive driving results in the highest inconsistency, while cautious driving shows the best consistency. However, under temperature inconsistency, this trend is reversed. This study clarifies the variation patterns of SOC inconsistency under different initial conditions and driving styles, offering useful insights for designing intelligent equalization strategies adapted to specific driving styles in electric vehicles.