Cylindrical battery thermal management based on microencapsulated phase change slurry

Abstract

The present study focuses on application of microencapsulated phase change material (MEPCM) slurry in cooling electric cars' batteries. These materials, benefiting from their high latent heat property, are especially capable of heat absorption while they impose excessive pressure drop to the system. This study aims to establish a trade-off between the cooling efficiency and pressure drop of the system. 186 batteries whose model is 18,650 with a serpentine arrangement, similar to that of Tesla car model S, are considered. The maximum temperature inside the battery, the maximum temperature difference of the battery pack and the coolant pressure drop are investigated as the critical parameters. Moreover, the temperature variation along the serpentine channel is also studied. In order to examine the thermal performance of the system, the maximum temperature limit of 313 K and maximum temperature difference of 5 K are considered for the batteries. The studied variables are discharge rate (3C and 5C), concentration of the MEPCM slurry (10% and 20%), and fluid velocity (up to 0.4 m/s). Results show that, for a specified velocity, application of MEPCM slurry reduces maximum temperature and the maximum temperature difference with respect to water. However, when the velocity rises, this effect diminishes which means that the application of the proposed material results in higher pressure drop and more energy consumption. Results also indicated that for the discharge rate of 3C, by the application of 10% MEPCM slurry at 0.1 m/s, the minimum thermal requirements are fulfilled bringing about the least pressure drop. These conditions for the 5C discharge rate are 20% concentration and 0.2 m/s fluid velocity.