Study On The Thermal Management System Of EV Square LiFePO₄ Battery Pack

With the continuous advancement of environmental protection and energy saving and emission reduction,the policy incentives and market demand for electric vehicles are increasing.As the main power source of an electric vehicle,the performance of power battery is closely related to temperature,which has a direct impact on the vehicle's power performance and safety.Keeping the battery pack working in a reasonable temperature range,while reducing the temperature difference between the battery cells is of great significance for ensuring the safety of the electric vehicle and improving the charge and discharge performance of the battery.This paper takes the square LiFePO₄ battery as the study object,analyzes the thermal characteristics and establishes the thermodynamic simulation model of a battery cell in ANSYS/Fluent.The validity of the model was verified by comparing with the experimental data.Establishing the simulation model of the electric vehicle and the heat generation rate calculation model of the battery pack by ADVISOR,then analyzes the dynamic performance of the battery pack.Designing the air-cooling structure of the battery pack,this paper analyses the heat dissipation effect of cooling air under different flow velocities and different structure parameters according to the temperature field distribution obtained by ANSYS/Fluent.This paper designs the battery thermal management system,determines the scheme and structure of the temperature acquisition module,the high temperature heat dissipation module and low temperature heating module,designs the control circuit,develops heat dissipation and heating temperature control strategies.Finally,the thermal management information system of the battery pack is built to enable users to grasp the working status of battery pack in time.The heat dissipation structure is optimized by changing the flow velocities,the airflow channel spacing between the cells and changing the air inlet angle.The simulation results show that the structure optimization can effectively improve the heat dissipation of the battery pack and reduce the temperature inconsistency between the cells.The heat management system controls the fan and the heating film to ensure the battery pack work in a suitable temperature range,therefore improving the heat dissipation efficiency and low temperature performance of the battery pack.The battery thermal management information system can display the operating parameters and working status of each module in time and provides information support for rational operation.