| China has been working on research and development (R&D) of electric vehicle’s related technology for years, and the electric vehicle industry in China has achieved rapid development, which is supported by National863Program of R&D. Not only a series of key technologies have been overcome, but also small quantities of electric vehicle products, researched and developed independently, have come into the market. In some areas of technology, Simultaneous development with Japan, the United States and Europe has been achieved. Power battery for electric vehicles, especially pure electric car, there is no perfect, comprehensive detection system and management system in the links of production and use. Battery management system (BMS) which can be bought on the current market have the data acquisition module, the data display module, high pressure and low voltage protection modules and the battery state of charge (SOC) estimating and display module, etc. Battery thermal management module has not been added to the battery management system, therefore, it is necessary to study the battery pack thermal management system, in order to narrow down the temperature difference among every the battery cell of the battery pack, so the temperature distribution is more even, thus can enhance electrochemical characteristics of the battery pack, improve the charging and discharging ability and life of the battery, and make BMS more perfect at the same time.This thesis is supported by Science and Technology Department of Jilin Province’s scientific and technological development projects,"Pure Electric Grade Commercial Bus development", and pure electric vehicles using Lithium iron phosphate power battery is its research subject. In this thesis, the method of combining experiment and simulation will be applied to study the temperature field of heat generation and heat dissipation of the battery pack, which will provide technical support to the overall design of the thermostat battery box.The main contents of this thesis can be summarized as follows:1. Analysis of the thermal characteristics of the lithium-ion battery. First of all, the thesis will make you understand the working principle, structure and electrochemical properties of lithium-ion battery to analyze the mechanism of lithium-ion battery heat. And then the thesis will analyze the temperature characteristics of the lithium-ion battery to find a correspondence between the battery temperature rising and ambient temperature, while the optimal temperature range of the discharge efficiency of the battery pack will be determined.2. Analysis of Lithium-ion battery packs heat temperature field simulation. Through establishing the thermal effect model of the lithium-ion battery and the model of the rate of heat generation, and then calculating thermal conductivity, specific heat capacity and density parameters of battery thermal model, the initial and boundary conditions of a thermal model will be finally ascertained. That realized the temperature field simulation of heat generation, and obtained temperature distribution after the battery heat.3. Analysis of Lithium-ion battery pack heat dissipation temperature field simulation. First of all, the advantages and disadvantages of the various heat transfer medium will be introduced, the air-cooled cooling mode will be determined, and simultaneously parallel ventilation heat dissipation structure will be used. Then, the air flow will be analyzed in order to establish the battery-air fluid-solid coupled models. Finally, by setting the solver methods and boundary conditions of the battery pack thermal model, heat dissipation temperature field simulation will be accomplished, and a good theoretical analysis of the preliminary design for temperature control battery box will be done.4. The overall design of the thermostat battery box. First, the overall design scheme of the thermostat battery box will be proposed, and a description of the function of the battery box will be done. Then, a detailed design and space layout on the shell of the battery box and the upper and lower fixture will be done. Next, a comparison and selection of heat dissipation equipment and heating equipment will be done. Finally, a detailed analysis of the layout of heat dissipation equipment, heating equipment and temperature sensors will be done. |
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