Study On Thermal Environment Simulation Of High Density Lithium Battery

Power battery as the main components of new energy vehicles, the advantages and disadvantages of the performance will directly affect the promotion and use of new energy vehicles. Lithium ion batteries due to its high specific energy, specific power,cycle number, low self discharge rate, and no pollution, etc. has become preferred power source for new energy vehicles.Lithium ion battery in work itself will generate a lot of heat, and usually the battery in the battery box arranged very compact, resulted in a great deal of heat accumulation,which makes the battery temperature increased sharply, it will seriously affect the battery performance, there may will lead to thermal runaway accidents. For the lithium ion battery pack to work with a good thermal environment, it is necessary to design effective battery pack cooling scheme, but also to ensure that the temperature uniformity of the internal battery.The main work done in this paper is as follows:1. This paper introduces the prospects of the development of new energy vehicles and power battery technology at the present stage of development, analyzed the battery thermal management the necessity and the research state of battery pack cooling cooling method.2. According to the internal structure and working principle of lithium-ion battery,combining the principle of heat production and heat transfer characteristics of lithium ion batteries, lithium ion battery thermal model is established, and the thermal analysis oflithium ion battery parameters is determined. And analyzed the computational fluid dynamics(CFD) in the application of power battery thermal analysis.3.Under the ventilation cooling scheme,the overall model of the battery pack is set up with the arrangement of the parallel and the fork,and the numerical simulation is carried out.The temperature field and flow field distribution of the battery pack are obtained.The effects of the air supply temperature and the air supply volume on the thermal environment of the battery pack are also analyzed.When the air volume is2500m3/h,The maximum temperature of the battery under the arrangement of the parallel and the fork is 304.02 K and 303.88 K,the maximum temperature difference was 4.54 K and 4.57 K.4.Under the liquid cooling scheme,designed separately S-shaped,Return to form,split-flow, double row,flow passage structure of four kinds of cooling plate,and set up the corresponding battery model, temperature field and flow field analysis were carried out for each model.The thermal property parameters of the fluid have great influence on the thermal environment of the battery pack.When the inlet mass flow rate is 24g/s,The maximum temperature of the battery pack under the four flow passage structure is 308.24K、307.06K、309.48K、309.27 K,the maximum temperature difference is 9.68 K, 8.03 K, 7.38 K, 4.40 K.