| As the only power output energy storage element-battery,its performance directly affects the development prospects of pure electric vehicles.However,the problem of heat loss of battery becomes the bottleneck restricting its development,so that it has been limited to certain specific ranges.Heat accumulation does not dissipate in time,resulting in a rising temperature inside the battery pack,not only reducing the mileage of pure electric vehicles and battery life,and even causing the battery to ignite or explode.Therefore,the research on improving the cooling structure of battery pack and optimizing the design is an important means to improve the mileage,battery life and safety performance of pure electric vehicles,and it is also of great significance to promote energy saving and emission reduction and promote the development of pure electric vehicle industry.In order to improve the working environment of the battery and effectively control the internal temperature of the battery pack,this paper establishes a three-dimensional simulation model of the battery pack based on the battery pack of a pure electric vehicle,and studies the temperature rise characteristics of the lithium battery monomer by experiments and simulations.On this basis,the temperature rise change inside the battery pack under multiple working conditions is simulated The improvement of air-cooled heat dissipation structure is studied.Based on the bionics principle,a bionic heat dissipation structure based on liquid cooling is proposed,and the optimization study of cooling working flow rate and initial temperature as variables is carried out,and the internal temperature of the battery pack is finally effectively controlled.The main research contents are as follows:1.Analyze the structure characteristics,working principle and thermal mechanism of lithium battery monomer,establish the simulation model of lithium battery monomer,analyze the thermal characteristics of monomer battery by combining experiment and simulation,compare the experimental and simulation results,verify the accuracy and feasibility of simulation,and provide the simulation scheme for the subsequent chapters;2.Based on the structural parameters of the battery pack of pure electric vehicle,a three-dimensional simulation model of battery pack is established,the Heat transfer mode under the actual working condition of lithium battery is analyzed,and the battery pack is simulated by CFD technology;3.According to the simulation results,the internal temperature change of the battery pack under multiple working conditions is analyzed,the extreme working conditions are explored,and the improvement of the air cooling heat dissipation structure of the battery pack is carried out under the extreme working conditions,and the results show that the cooling capacity of the air-cooled cooling structure with the baffle is better;4.Based on bionics theory,this paper presents a design method of bionic heat dissipation structure based on liquid cooling,designs and establishes four kinds of bionic heat dissipation topology by using the network topology with excellent heat transfer characteristics in nature,simulates the temperature field of four kinds of structures,compares and analyzes the heat dissipation performance of four kinds of bionic heat dissipation structures,The results show that there are great differences in the heat dissipation capacity of different bionic heat dissipation structures,among which the heat dissipation capacity of spider web bionic heat dissipation structure is optimal;5.Based on the air-cooled heat dissipation structure of the baffle,the simulation model of the Spider-Type bionic heat dissipation structure based on liquid cooling is established,and the temperature field of the battery pack is simulated under extreme operating conditions,and the results show that the high temperature in the battery pack is obviously improved,but the temperature distribution between the monomer batteries is not uniform,and the difference The optimization study of the flow rate and initial temperature of liquid-cooled work is carried out,and the internal temperature of the battery pack is effectively controlled within 317.9K,and the temperature difference between the monomer batteries is controlled within 4.7K,which realizes the increase of the mileage and battery performance of the pure electric vehicle. |
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