Study And Optimization Of Heat Dissipation Performance For Lithium Battery Vehicle

With the continuous development of battery,motor control,and new energy vehicle technology,the continuous mileage of new energy vehicles has been increasing,and public facilities,for example,battery charging devices have been continuously improved,and the new energy vehicles has gradually been accepted by people.Lithium-ion batteries are expected to be the ideal power source for new energy vehicles due to their superior comprehensive performance.However,lithium-ion batteries are very sensitive to temperature's change,which seriously restricts the development of power batteries because of safety problems it caused.In order to improve the heat dissipation performance of lithium-ion battery packs,the following work has been carried out:(1)It analyzes the heat generation and heat transfer characteristics of lithium ion batteries,and understands the heat source and heat transfer mode of lithium ion batteries.The thermal property parameters of lithium ion battery are calculated and the three-dimensional mathematical thermal model of lithium ion battery was established by CFD technology to simulate the temperature rise of single cell under different discharge rate.The increase in temperature and internal resistance of the single-cell lithium-ion battery under different discharge conditions were tested.The correctness of the lithium battery heat generation model was verified by comparison experiments and simulation results.(2)According to the different battery arrangement and battery structure,four different battery pack geometric models were established,and the one-way blow cooling simulation under 1C and 2C discharge rate was carried out,analyzed the influence of the arrangement of the battery and the presence or absence of the cooling medium on the heat dissipation of the battery pack,and obtained the battery pack model with the best heat dissipation effect under the one-way blow condition.(3)Simulated the air cooling and heat dissipation conditions of the battery pack under the same discharge rate and different ventilation modes.It found that the heat dissipation effect of the one-way suction cooling method is obviously better than that of the one-way air blowing cooling method;the reciprocating suction cooling method is proposed,and the reciprocating suction heat dissipation can effectively reduce the maximum temperature and the maximum temperature difference of the battery pack.(4)Taking cross row battery with air flow in it as the research object,the effects of thereciprocating cycle,the battery pole air layer thickness and the initial temperature of the cooling air on the heat dissipation effect of the battery pack are analyzed in detail,using multi-factor orthogonal test.The heat dissipation optimization strategy of the battery pack under low wind speed cooling conditions is obtained.