Study On Energy Management Strategy Of EV Based On Battery Pack Temperature Status

With the aggravation of the global energy and environment crisis, the traditionalauto industry is confronting unprecedented challenges. To develop new energy vehicleswith lower energy consumption and environmental pollution has become the trend ofautomotive technology. As one type of new energy vehicles, electric vehicle (EV) hasbecome the trend of vehicle development, for its merits as low-energy consumption,simple in construction, low noise and vibration, pollution free. Power battery is the onlypower source in EV, so the performance of EV is directly related to power battery. Thelithium-ion battery is the first choice of power source for EV, for its high operatingvoltage, high specific energy and specific power, low self-discharge, long life span, nomemory effect and population-free.The power battery pack installed in EV generates a lot of heat in the process ofcharging and discharging. The generated heat may lead to temperature rise of batterypack if effective heat dissipating measures are not taken, especially when the batterypack operates at large currents. Excessively high working temperatures will reduce theperformance and life span of lithium-ion battery pack, and it may even lead to batterypack permanent failure. So the temperature of battery pack must be controlled.When discharging frequently at large currents, the lithium-ion battery packgenerates a lot of heat, which leads unmanageable temperature rise of battery pack.Therefore, an output power control strategy of battery pack based on over-temperatureis proposed: when the battery is in the state of over-temperature, the output power ofbattery pack will be limited properly to reduce the heat production and control thetemperature rise.The main details in this paper are as follows:①Based on the requirements of power performance and fuel economy for EV,combine with the vehicle basic parameters, powertrain parameters match of the EV isdone.②The internal structrure, operating principle, characteristic parameters and heatgeneratrion characteristic of lithium-ion battery is studied, and the calculation model ofheat generation rate is proposed. Based on the work above, the simulation model oflithium-ion battery pack in the software of ADVISOR is built.③In order to ensure the uablity and safety of lithium-ion battery pack, the temperature rise of battery pack under conditions of operating frequently at largecurrents must be controlled. Therefore, an output power control strategy of battery packbased on over-temperature is proposed. The EV performance simulation and analysisunder various working conditions are also carried out, to verify the effectiveness ofproposed control strategy.