Abstract: The LiFePO4 battery pack are taken as an example for the study temperature of pure electric vehicles battery pack at different driving conditions. Based on the Fourier’s law and the law of conservation of energy, the mathematical and finite element model and thermal conductivity of the battery pack are developed. By using FLUENT, the temperature distribution and the distribution of the flowing field of lithium-ion battery pack in a closed box are simulated when electric vehicle running at different constant speeds. Vehicle test is conducted to find the temperature distribution of measuring points in battery pack under different running conditions. The validation of simulation model is testified by proving that there is a good consistence between simulation and test results. Meanwhile, the influence imposed by different running speeds on the rising temperature of battery pack is found. Based on the authenticated simulation model verified by test results, the influence of the ambient temperature and the gradient of the road on rising temperature of lithium-ion battery pack is simulated and analyzed. The optimized operational environment temperature range is obtained as 20-30 ℃. Then the gradient have a great impact on the battery pack’s temperature rise.

Key words: Lithium-ion battery pack;temperature field;FLUENT;temperature difference