| Due to the high voltage, high discharge current, high energy density and environmental protection, lithium-ion batteries have been widely used in electric vehicles and power equipment. Because of the resistance of lithium-ion battery, the charge current and discharge current could generate a great deal of heat that lead to the battery temperature rising. If the batteries were not cooled adequately, the excessive temperature might destroy the batteries or reduce the life of batteries, even lead to safety accidents that damage the life and property of consumers. The heat dissipation of batteries is so important that we have to research it when we design the batteries. Studying the lithiumion batteries’ heat dissipation and temperature distribution to find out the influence factors of heat distribution will significantly improve the heat dissipation performance of lithiumion batteries and increase the safety of electric vehicles or power equipment.This paper was supported by the project of Development of Advanced Energy Storage Devices, which was founded by the Guangdong province’s special foundation(2011N071) that aimed to introduce innovation team. The heat generation and dissipation of single lithium-ion cell, batteries and one package of air-conditioning were done based on experiment and computational fluid dynamics(CFD) method.Firstly, constructed the two-dimensional model of lithium-ion battery electrode and calculated the electric field distribution of the electrode. The result showed that the current mainly concentrated in the near of the tab.Secondly, measured some physical parameters of power lithium-ion battery and constructed heat generation model of a cell which was numerically stimulated by CFD. We used the surface temperature of the cell to valid the model. When the cell discharged form SOC=1 to SOC=0 in the current 10 A, the error of the model would not exceed 0.5℃. When the cell discharged form SOC=1 to SOC=0 in the current 60 A, the error of the model would not exceed 2℃.Thirdly, the influence factors on battery heat dissipation such as the material and the thickness of the battery shell had been analyzed. The result showed that the steel shell with the thickness about 2mm owned the best performance of radiator. Furthermore, we researched the back cover of battery pack influences on batteries’ heat dissipation. The results demonstrated that removing the contact surface of batteries’ cover and bottom could improve the performance of the heat dissipation.Finally, designed a package of air-conditioning which have good heat dissipation performance. Considering the coupling of the battery packs and air flow fields in the battery package, we proposed three projects of the battery package. The discharging process of batteries in the package was numerically stimulated by CFD to choose and optimize the layout of the battery package. Comparing the temperature field of the three projects in the package, we found that the third project had best heat dissipation performance. So the third project was modified to control the maximum temperature in the package cabinet and enhance temperature distribution uniformity. When the package discharge form SOC=1 to SOC=0 in the current 200 A, the maximum temperature would not exceed 47.38℃ and the maximum difference temperature of batteries would not exceed 5℃.The results showed that the optimized battery package could meet the requirements for heat dissipation the temperature uniformity. |
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