Numerical Investigation Of Air-cooled Power Battery Thermal Management System Technology

Power battery is one of the three key points for promoting the development of Electric Vehicles. Power battery pack, which is composed of so many single batteries, can provide driving sources to drive Electric Vehicles. The main factors that affecting the performance of battery pack are temperature rise and temperature difference between batteries.Based on the thermal control research of power battery, the battery thermal management system can realize the efficient of power battery.Based on the existing air-cooled battery thermal management structure, an optimal design was derived that opening the additional vent on the battery pack, that can change the fluid flow filed. It was found that the key factor of affecting the temperature rise and temperature difference of battery pack was fluid velocity. The air-cooling network model that based on fluid flow resistance was proposed. Also the effect of different designing structure on fluid distribution was discussed.The main conclusions of this paper are following:(1)That, opening the vent on battery pack, could efficient decrease the temperature rise and temperature difference of battery pack. The cooling performance of battery pack would achieve optimal state when the vent was located on the point, which was near the inlet, opposed to the outlet of battery pack. At this conditions, the temperature rise and temperature difference between batteries were just 28.9K and 3.4K, which decreased by 1.84%and 62.9% compared to the original structure, when the inlet mass flow was 0.0262kg/s.(2)The cooling performance of battery pack could significantly be improved when increasing the area of vent. The temperature rise of battery pack decreased by 3.29 K, for case 4, when theg increased from 0.2 to 1.5. When the area of vent was equal to that of vent, the cooling performance was the best state. At the same conditions, the local temperature difference decreased by 0.34 K, when theg increased from 0.2 to 1.5. So, there was no need to continue increasing the area of vent, because the cooling performance would not be obvious change.(3)The temperature rise of battery pack would be linearly increasing when the air inlet temperature was enlarged, which had no influence on local temperature difference. But the effect of changing of gap between batteries vise verse. The temperature rise decreased by 0.26 K, when thefincreased from 0.53 to 0.96.(4)The effect of frictional resistance loss could not be ignored when the flow resistance network model was used to design the air-cooled battery thermal management system. The velocity difference could be decreased when the distribution plate angle was increased. Increasing the gap between batteries could achieve fluid distribution more uniform.