Battery thermal management systems by using DI water and PCF with Nano-encapsulated Tetradecan-1-ol for Lithium-ion batteries

Lithium ion battery (LIB) is the major power source in electric vehicles (EVs) and its thermal management is essential. Present study explores thermal regulation of LIB utilizing phase change fluid (PCF) which consists of nano encapsulated phase change material (NEPCM) in base fluid, specifically Tetradecan-1-ol encapsulated in polymethyl methacrylate. Three-dimensional model is developed for three different designs of battery pack (BP) and simulated with 0 to 7 % concentration of NEPCM, 1C to 5C cell discharge and with Reynolds number (Re) of 121.09 to 1937.52 using PCF and deionized (DI) water coolants. BP-2 with PCF is the best combination for thermal management among different configurations and phase transition process of PCM was effectively used in it. At lowest Re and highest discharge, PCF has superior performance than DI water due to optimisation in phase transition of PCF at reduced pumping power. DI water fails to regulate the system at 5C and lower Re of 3C. Inclusion of 4 % NEPCM reduces 47 K and 79.64 % in maximum temperature and temperature difference, respectively and increases convection HTC by 6.15 times compared to DI water in BP-2 at Re of 121.09 and 5C discharge. It is found that cell discharge rate significantly influences figure of merit (FOM) and coefficient of performance (COP) than the concentration of NEPCM across various coolant dynamic conditions. The change in C-rate is significantly reflected in FOM and COP at lowest Re of 121.09, reaching a magnitude of 198.01and $1.83\times {10}^6$, respectively with 2 % NEPCM at 5C discharge.