| Due to the advantages of less pollution emissions, high energy efficiency andlow noise, electric vehicles are becoming one of the mainstreams for future vehicles.The improvement of performance for Lithium-ion battery packs which are the corecomponents of electric vehicles is the key issue for developing of electric vehicles.Temperature has a significant impact on the performance of battery. As is shownabove, we should take effective measures to control the temperature of battery packsto ensure the safe and effective operation of electric vehicles.Phase change material(PCM) cooling is one of most important methods forthermal management of battery pack. The PCM-water cooling method is proposedbecause the PCM itself does not have heat dissipation potential. It is shown that thetemperature of battery with PCM-water cooling method is54.4degree at5Cdischarge rate, while the temperature of battery with PCM cooling is62degree. Thetemperature controlling effect of PCM-water cooling is much better than that of PCMcooling.A novel cooling method coupling metal fins and air flow is proposed because ofthe complexity of PCM-water cooling system and high maintenance cost. Thetemperature effects are discussed at the same discharge rates. It is shown that thecoupling of metal fins and air flow is much more superior to common air cooling interms of controlling the maximum temperature of the battery. The temperature ofbattery at the end of discharge is47.4degree. The mechanism of coolingenhancement by fins is discussed. The thermal conductivity of the fins proves to be acritical factor which determines the cooling effect.According to the temperature effects on different areas of fins, the heatdissipation of fins which close to the air inlet and outlet is the best. So a novel coolingmethod coupling I-shaped metal fins and air flow is proposed. The results show thatthe coupling of I-shaped fins and air flow is much more excellent than the coupling ofrectangular fins and air flow. The coupling of I-shaped fins and air flow can controlthe temperature of battery to below55degree at different heat transfer area of finswith7C discharge rate. The weight of the battery pack will be reduced effectively byselecting the size of fins flexibly. |
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