Numerical Simulation On The Thermal Property And Thermal Management Of The Lithium-ion Battery For Electric Vehicle

Lithium-ion battery has great advantages in electric vehicle applications for its excellentperformance. However, it is also worth noting that lithium-ion battery produces a largeamount of heat while working, which is the most important cause of the power system failureand safety accident. Therefore, it is needed for the development of modern electric vehicleindustry to design a reasonable and effective lithium-ion battery pack thermal managementsystem. This paper establishes a lithium-ion battery thermal effect model based on the heatproduction principle carries out numerical simulations to analyze the temperature distributionof lithium-ion battery in different usage conditions and applies different radiation devicemodels for the lithium-ion battery optimization design and simulation analysis.The main jobs in this thesis include:(1) The research status of electric vehicle battery thermal management technology wassummarized on the basis of the related literatures. After making a comparative analysis of thetypes and structural features of the existing vehicle power batteries, model26650LiFePO4cylindrical lithium battery was chosen as the research object as to its high safety and longservice life. Then the reaction principle of and the heat production principle of Li-ion batterywere described and the thermal characteristics of the lithium-ion battery was analyzed(2) The battery thermal effects model was established and the ANSYS software wereapplied to emulated the thermal characteristics of lithium-ion batteries under the naturalconvection and to study the temperature rise situations in the same ambient temperature whileat different discharge rate and at the same discharge rate while in different ambienttemperature. Finally, under the same test conditions,15A pulsed electrical dischargeconditions were simulated. And combined with experimental data, the simulation results wasanalyzed and compared to verify the reasonableness of thermal effect model.(3) The cell and battery pack cooling device model were established base on Lithium-ionbattery thermal effects model. Then simulation analysis of its velocity and temperature fieldsunder forced air cooling for researching the rationality of radiating device. And for thestaggered arrangement and add baffles schemes simulation analysis. The results show thatoptimization can achieve good thermal lithium-ion battery pack, fan-shaped deflector can set the temperature control within5℃and basically meet the job requirements.(4) In view of the temperature inconsistencies along the duct flow direction within thebattery pack in the air cooling system, a liquid-cooled heat sink is applied for the solution ofdefect; the cooling device includes thermal sleeve and the tube which is designed as to theflow. The simulation results show that under10C discharge conditions, the temperaturedifference between the internal battery is only3℃, liquid cooling systems can improve thethermal performance.The study results can provide a reference for the battery thermal management systemwhole design.