| Hybrid electric vehicle (HEV) has been developed rapidly, and it has become an important future direction of the autos. As the main energy storage components, battery affects the performance of HEV directly. With the characteristics of high specific energy, high specific power, long life, fast charging, faint memory effect, less pollution, etc., Nickel-hydrogen (MH-Ni) battery becomes the first choice for HEV.MH-Ni battery will generate a lot of heat during charging and discharging, if the heat is not dissipated promptly, it can lead to overheat of the battery pack, temperature difference among the battery modules and quantity diminution of electricity, thus affects the performance and life of the battery. In order to improve the reliability of battery, not only the battery temperature is required to maintain below a certain critical temperature, but also the temperature difference among the battery modules is required to keep within the reasonable bounds. So, battery pack has a good cooling system or not is particularly important. Using numerical simulation and test validation methods to analyze the temperature distribution of the single MH-Ni battery under given conditions, predicting the thermal performance of battery packs and optimizing the cooling system structure have important practical significance.The main works in this thesis include:â‘ Calculation formula of battery heat was derived according to MH-Ni battery's electrode reaction and heat theory. A three-dimensional, transient heat dissipation model was built for MH-Ni battery, based on the mass, momentum and energy conservation equations.â‘¡The model was applied to simulate the temperature field of the single MH-Ni battery using computational fluid dynamics (CFD) software. A temperature measurement experiment of the single MH-Ni battery during charging and discharging periods was carried out to confirm accuracy of the simulation analysis. It indicates that the simulation results can consist well with the experimental data, and the temperature field model of single MH-Ni battery can reflect the temperature distribution information of the surface of the battery shell.â‘¢In the light of domestic research status of battery cooling system, two loading modes of the body heat were applied to carry out the static-state simulation of the MH-Ni battery pack temperature field. One is that the body heat was loaded on the inside of the entire battery shell, and the other one was loaded on the galvanic pile area directly. The influence of the two loading modes on simulation results and the difference between them were analyzed from the perspective of numerical simulation.â‘£An optimization scheme of the MH-Ni battery cooling system was proposed and simulation analysis on both steady and transient state of the optimal model of battery cooling system was carried out. The results showed that the optimal model performed favorable cooling and diminished the maximum temperature of the battery surface as well as the maximum differential temperature at the same place between battery monomers effectively, thus satisfied the application requirements of the MH-Ni battery on hybrid electric vehicles.
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