Thermal Analysis And Cooling Optimization Research On Lithium-ion Battery Pack

Lithium-ion battery with many advantages such as a higher voltage platform, the larger energy, high charge-discharge efficiency and long life has been widely used in the field of new energy vehicles and energy storage batteries. Referring that lithium-ion batteries are widely used in the field of electric vehicles, the lithium-ion battery energy storage element is extended to the field of rail transportation in order to establish a conservation-oriented integrated transport system. But there are a lot of problems while it’s being high-speed development, especially the impact of temperature difference on the performance of the large battery pack groups, making the cooling system designing and thermal management designing about the power lithium-ion battery pack to be an issue greatly concerned by researchers. We not only ensure that the battery work in the critical temperature range, but also control the temperature difference among all batteries in the pack, so as to ensure the battery performance and cycle life unaffected.Therefore, this paper systematically simulate and analyze the temperature distribution of lithium-titanate battery pack on hybrid EMU, from the cell to the cooling system, mutual vivificating between simulation and experiments to predict the thermal performance of battery pack and propose the optimized solutions. The research contents and results of the paper are as follows:(1) The heat transfer model of a lithium-titanate battery is established, heat generating rate is estimated and fit a function about time type, the heat transfer model and heat rate calculation formula are verified by experiment with high accuracy in the lithium-ion battery temperature numerical simulation.(2) Using CFD technology and software the model of lithium-titanate battery pack is simplified and meshed by finite element, the temperature simulation when the battery work on charging and discharging cycle is made under the condition of the cooling, and the flow field and temperature distribution results are analyzed to predict cooling performance of the battery pack.(3) According to the battery pack thermal simulation results the main problems existing in cooling analyzed and two possible optimized solutions are proposed, the finite element modeling and temperature simulation are again made for the battery pack of different schemes, then the simulation results are obtained and compared with the original structure to study the impact of these schemes on the cooling performance...