Structure Design And Experimental Research Of Lithium Battery Pack Based On Air-cooled Heat Dissipation

In recent years,with the rapid development of the automobile industry in China,the serious environmental pollution and energy scarcity problems have also attracted more attention and attention from the country.China’s crude oil imports ranked first in the world in 2017 due to the country’s lack of petroleum resources.At the same time,the increase of the number of traditional fuel vehicles leads to more automobile exhaust emissions into the atmosphere,causing serious greenhouse effect,which has brought great damage to the natural environment and threatened people’s health.In this case,the development of China’s electric vehicle industry has brought unprecedented opportunities for development,the future of electric vehicles gradually replace the traditional car is inevitable.Power battery as the power source of electric vehicles,its safety performance and endurance is particularly important,and the performance of power battery is closely related to the temperature,the temperature is lower or higher will affect the safety and performance of lithium battery.Lithium battery will release a lot of heat energy in the process of charging and discharging.If these accumulated heat can not be discharged in time,it will bring great safety risks.Therefore,it is very important to establish a suitable battery heat dissipation management system in electric vehicles.This paper mainly does the following aspects:(1)In this paper,the 18650 single lithium battery was used as the research object,and the temperature rise experiment of the 18650 single lithium battery was carried out at 25℃,and the relevant thermal property data of the 18650 lithium battery was obtained.At the same time,the internal structure,working principle and thermal generation mechanism of the 18650 lithium battery were analyzed.(2)An experimental platform for lithium battery modules was built.Forced air cooling experiments were carried out on the battery modules at discharge rates of 1C,2C and cooling air of 1m/s and 1.5m/s under the initial working conditions.In this paper,the ICEM modeling software was used to create the experimental model,and then the Fluent software was used to carry out the simulation analysis under different conditions.The simulation data and experimental data were compared,and the experimental data and simulation data were consistent,which verified the correctness of the simulation analysis.(3)In order to improve the temperature consistency of the battery,the methods of staggered tilt,left and right staggered movement of the battery module,up and down staggered movement and mixed staggered movement of the battery module were proposed.(4)The structure design of the combination of the staggered tilt of adjacent batteries and the trapezoidal spoiler and the hybrid staggered movement and the longitudinal spoiler are introduced.Compared with the initial working condition,the maximum temperature of the battery module is reduced by 12.01(23.54%)and the maximum temperature difference is reduced by 7.89℃(89.97%)in the optimal working condition after the combination of the staggered tilt of the battery module and the trapezoidal spoiler.Compared with the initial condition,the maximum temperature of the battery module is decreased by 13.06 ℃(25.6%)and the maximum temperature difference is decreased by 8.45℃(96.35%)in the optimal condition of the hybrid staggered movement of the battery pack and the longitudinal spoiler.(5)In the working condition of mixed interlaced movement and longitudinal spoiler,three factors and four levels of orthogonal tests were carried out.Through range analysis and variance analysis,it is found that when the cooling air velocity is 2m?s,the length of the spoiler is 63 mm,and the number of spoilers is 4,the heat dissipation performance of the battery module can be greatly improved.