Simulation Study For The Cooling System Of Power Battery Based On Thermoelectric Cooling

Lithium-ion battery is widely used in electric vehicles(EV)because of its high voltage platform,specific energy and charging and discharging efficiency.However,there are many problems for the application of lithium ion battery,especially,the impact of temperature on the battery's performance and lifetime.Therefore,researchers have paid lots of attention on the reasonable way of heat dissipation.In view of the thermoelectric cooling with the advantages of hot and cold end flexible conversion,high reliability,high security,this paper applied the thermoelectric cooling to solve the thermal problem of battery,which have solved the temperature control problem of the lithium-ion battery under high temperature working conditions.The thesis mainly introduced and did the researches form the following aspects:(1)Studied the heat generating mechanism and the heat transfer characteristics of the lithium-ion battery,calculated the thermal parameters and heat generation of the battery,so,determined two kinds of cooling load 50 W and 90 W.(2)Designed a battery-thermoelectric cooling system,established the electrical equivalent model for thermal resistance model.by using the similarity between the thermal phenomenon and electric phenomenon.Did the analysis based on the performance of the model in the environmental temperature of 37 ?.The result have shown that the thermoelectric module's working voltage,thermal resistance and the environment temperature has a significant effect on the performance of the cooling system.With the increase of voltage,the temperature of heat source first increases then decreases.There was voltage U = 13 V making the lowest heat source temperature 35?.The hot side of thermoelectric module have influenced the performance of the cooling system effectively,and with the increase of CFM,the heat source's temperature decreased.When the CFM got the value 80,the heat source's temperature decreased slowly.The higher the ambient temperature,the higher the heat source's temperature,however,there was the same voltage U = 13 V making the lowest heat source temperature.The value of the cooling load determined the number of thermoelectric module,we find that two thermoelectric modules can meet the demand of heat dissipation of battery,they could got the refrigerating capacity for 93 W.(3)According to the result of thermal resistance model,we established the physical model in CFD software.We have analyzed the impact of the number of thermoelectric modules and the heat pipes on the battery surface temperature.The study have shown that the thermoelectric module could decrease 6? more than simple air-cooled.Three thermoelectric modules could got the temperature only 2 ? higher than four thermoelectric modules,which could reduce one thermoelectric module for two cells.The addition of heat pipe could reduce the battery surface mean temperature difference for 4?,which has played a good effect of heat transfer.Battery temperature control could be done by double adjustment of CFM and current,however,the CFM played more effect than current did.