| The pure electric vehicle doesn’t generate any polluting emissions during working,which benefits the environmental protection, especially the cleanliness of the air. As theonly energy storage component of the electric vehicle, the dynamic battery system ischaracterized by simpler structure compared with the hybrid one, which also facilitatesits maintenance. Meanwhile, the performance of the dynamic batteries will directlyinfluent the vehicle performance.The dynamic battery pack of the electric vehicle will generate much heat whiledriving. If the heat can’t dissipate in time, the battery temperature will rise rapidly andthe temperature distribution will be uneven, which in turn severely deteriorate theworking efficiency, service life and safety performance of the battery pack. Therefore,based on the newly-established battery’s thermal generation model, this thesis usesnumerical simulation technology to analyze the temperature field of the Lithium-iondynamic battery pack under different working conditions, and then simulates the batterypack’s dissipation properties. Followed with upon simulation results, the optimizationprocess of the heat dissipation structure is carried out, which holds great practicalsignification to improve the usability of the Lithium-ion dynamic battery pack. Thisthesis applies Fluent software to numerically simulate the temperature rise of singlebattery and compares the simulation results with the experimental one according to thecomputational fluid dynamics (CFD) theory. The dynamic battery pack uses liquidcoolant to cool down the batteries. The temperature field simulation and the temperaturedistribution analysis of the battery pack is conducted using CFX software. Optimizationmeasures are brought forward on the basis of aforementioned studies. And then thesimulation of the battery pack’s cooling conditions under different cooling status iscarried out.The main contents of this thesis are listed as follows:①The heat generation and transfer mechanisms of the battery are analyzed. Athree-dimensional heat generation model for the Lithium-ion battery was establishedaccording to the laws of thermodynamics and conservation of mass, momentum andenergy of heat transfer theory.②The thermal performance-related experiments of single Lithium-ion battery areconducted. And then simulates the temperature and internal resistance characteristics of the battery at different temperature and charge-discharge current, followed with thesimulation of the battery’s temperature field. The result of the simulation matches theresult of the experiment well, which implies the battery model is reasonable and theparameter settings of the numerical calculation is correct.③The model of the total electric vehicle is established with the simulationsoftware ADVISOR to simulate the dynamic characteristics of the vehicle underdifferent driving conditions, which is in order to obtain the SOC, heat generation rateand current variations of the battery pack.④Numerical simulation of the flow and temperature fields of the Lithium-ionbattery pack (original scheme) is analyzed by using CFX software based on the CFDtheory. An optimized plan of the battery pack’s heat dissipation system is proposed andthe effect of this new plan is simulated. |
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