Optimization Analysis Of Heat Dissipation Structure Of Power Battery Module

Temperature is the main factor that affects the charge and discharge performance of battery pack.Whether the temperature is too high or too low,it will affect the charging performance of the battery.For the single cell,too high temperature will accelerate battery aging,reduce cycle life,or cause combustion and explosion.If the temperature is too low,the charge and discharge performance of single cell will become worse.For the vehicle power battery module,the local temperature is too high or the temperature difference is too high,which will both cause the overall performance of power battery module to decrease.Therefore,it is very crucial to control the temperature of battery pack in a reasonable range.On the basis of reviewing the heat management literature of battery group at home and abroad,the lithium ion battery group has been taken as the research object for the problem of high temperature and uneven distribution of the temperature of the battery group.Then the temperature field of heat dissipation structure of the battery group under different wind speed and the different charge rate conditions can be analyzed thourgh the Bernardi heat generation rate model.Firstly,Li-ion battery has been taken as the research object,the air cooling method can be used to analyze the heat dissipation of the battery pack.During the heat dissipation of the battery,the internal heat production of the lithium ion battery can be transferred to the outer wall of the battery by heat conduction.The cooling air can also be exchanged with the outer wall of the battery through heat convection,and the wall and the cooling air are both adiabatic.The finite volume method has been used to solve the heat transfer control equation and the fluid control equation.Compared with the maximum temperature,temperature difference and temperature variation coefficient of three kinds of heat dissipation structures in circular,semi-circular and rectangular structures,the maximum temperature,temperature difference and temperature variation coefficient of the rectangular outlet heat dissipating structure battery group are lower than the all of other two heat dissipation structures.And the temperature uniformity of the battery group is best in rectangular outlet heat dissipating structure.In addition,the rectangular heat dissipating structure which is the the optimum heat dissipation structure must be optimized the analysis by using the minimum temperature of the battery pack as the minimum in order to further reduce the maximum temperature of the battery pack and improve the temperature uniformity of the battery pack.All have been used in this optimization and analysis that is the method of response surface and the variables of outlet size,top distance,distance between the bottom,top width of the box and the diameter of the inlet diameter.The results show that the maximum temperature and the temperature difference both are smallest when the top width of the box,the inlet diameter and the inlet diameter respectively are 70mm×45mm,4mm,5mm,92 mm and 90 mm.The smallest maximum temperature and the temperature difference respectively are 304.21 K,6.22 K,and the temperature uniformity of the battery pack is best in this condition.