The thermal management system is essential for the safe and long-term operation of the power battery. The temperature difference between the individual cells exceeds the acceleration of the battery performance, which leads to battery out of use and affects the performance of the vehicle. Compared with the low heat transfer coefficient of the air-cooling system, the complex structure of the liquid-cooling system and the large quality of phase change material system, the heat pipe has high thermal conductivity, strong isothermal performance and light weight, it’s an efficient cooling element that can be used for thermal management.
In this study, the flat plate heat pipe(FPHP) is used to manage the temperature of the battery, through experiments, the optimized placement of the flat heat pipe is obtained. Based on this, the thermal performance of the thermal management system is studied, thus achieve the purpose of reducing the maximum temperature of the batteries and balancing the temperature difference between batteries.
In this paper, a square LiFePO4 battery pack is taken as the object, and the battery heat generation-heat transfer-heat dissipation is the main line. Firstly, the battery heat generation model is established according to the thermal characteristics of the battery, and then based on the heat transfer characteristics of the FPHP, establish the heat transfer model of FPHP. Then the thermal management performance of the battery pack under the conditions with and without FPHP was studied by different discharge magnifications experiments. By comparing with simulation results and the natural cooling results, the superiority of the flat heat pipe at different discharge rates was obtained.
Studies have shown that this thermal management system keeps the cell temperature difference within 3 °C. Used in electric vehicles, it provides reference and support for future thermal management of high-power batteries.