| In the tense situation of natural resources,the electric car has become a hot topic,which sets off an electric car boom.As the core of electric vehicles,the performance of power battery determines the performance of electric vehicles.The main factor affecting the performance of the power battery is the temperature,and long-term operation under too low or high temperature may cause a significant decline in available capacity,the chemical performance and service life of power battery,even lead t thermal runaway,and endanger the safety of electric vehicles and passengers.Therefore,it is necessary to study the thermal characteristics of the power battery,the design of a reasonable battery pack cooling structure and battery boxIn this paper,LiFePO4 power lithium battery is taken as study object,a thermal model of battery is established,and experiment is taken to verify its effectiveness.The temperature field of the battery box is simulated and analyzed,and the measures to improve the cooling capacity and temperature uniformity of the battery box are introduced.On this basis to complete the design of the battery box system.The main contents are as follows:(1)The working principle and structure characteristics of the power lithium battery are studied in detail,and the mechanism of heat generation and heat transfer is analyzed deeply.At the same time,the temperature rise experiment of the single cell was carried out at different charging and discharging magnification.The influence of different charge/discharge ratio on the temperature distribution of the single cell was analyzed,and the experimental model was provided for the experimental model.(2)The three-dimensional thermal effect model of the power lithium battery was established to determine the relevant parameters and boundary conditions of the thermal model.At the same time,the simulation model of the single cell was established,and the thermal simulation was carried out to analyze the heat production of the single cell under different discharge magnification and different ambient temperature As well as the battery surface temperature distribution,and through comparison with the experimental data analysis,proved the effectiveness of the simulation model.(3)Based on the practical engineering application,the simulation model of the initial model is extracted and the multi-factor numerical calculation is carried out.The effects of different magnification,different wind speed and temperature on the temperature field of the initial model are studied.The influence of the distance between the battery module,the angle of the inlet and outlet and the surface treatment of the air duct are studied.The results show that the angle of the air inlet is changed and the inlet surface method of handling can effectively improve the heat dissipation capacity of the battery pack.And developed a dual-inlet air battery cooling structure,combined with the surface treatment method,to get a satisfactory battery duct structure. |
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