Simulation-Based Investigation of Lithium-Ion Battery Pack Discharge Characteristics in Electric Vehicles

Abstract

The high rate of development in Electric Vehicle (EV) technology has made it necessary to closely model and simulate energy storage systems to achieve the optimum performance, efficiency, and safety. This paper illustrates a simulation investigation on the nature of discharge of a lithium-ion battery pack with a specific design to be used in EV applications. Equivalent circuit model an equivalent circuit model is reduced to a detailed model, including the dynamic behavior of the battery under different load conditions. The model uses important parameters that include: internal resistance, open-circuit voltage, State of Charge (SOC), and current response in order to effectively model the electrochemical processes taking place inside the cells. Different scenarios have been simulated using MATLAB/Simulink and have been used to analyze the voltage response, energy output, and efficiency of the pack over time. The findings identify the non-linear nature of voltage-SOC relationship, changes in discharge curves due to changes in loads, and the effect of internal resistance on thermal and electrical performances. In addition, the paper examines the implications of discharge dynamics on the delivery of power to the EV drivetrain, which is useful in enhancing the energy management strategies. The results indicate that proper discharge modeling is essential in EVs to size battery, thermal and state estimation. This simulation model can be useful in helping researchers and designers to optimize the performance of battery packs, forecast degradation patterns, and aid the creation of superior Battery Management Systems (BMS).