Comparison between Different PCM Mediums and Dielectric Fluid for Hybrid Thermal Management of Electric Battery Packs

- In this paper, a hybrid cooling strategy for Lithium-ion electric battery packs is developed through the combination of air, liquid, and phase change material mediums. The hybrid strategy consists of the primary cooling medium that surrounds all the Lithium-ion cells and is in direct contact with the surface of the cells. The secondary cooling medium is housed within liquid channels placed in the battery pack to extract heat from a primary cooling medium. Furthermore, an air duct is placed at the top of the battery to extract heat from the fluids that are stationary within the liquid channels. Three distinct concepts are developed to compare the effect of phase change material and liquid medium as the primary cooling medium. In the first and second concepts, the primary cooling medium used is a phase change material, and in the third concept, it is an electrically insulated fluid. The numerical model is validated from experimental results in the open literature. Transient numerical studies were conducted and validated. The results indicate that through the first concept, the maximum temperature was limited to 31.5  C and the temperature uniformity to 1.75  C. Moreover, this strategy does not require excessive pumping fluid power and high air velocities, which implies that less energy is required for the operation of the thermal management system.