Design Strategy for Hybrid Thermal Management Using Various Composite Phase Change Materials

The growing demand for high-performance lithium-ion batteries in electric vehicles has heightened the need for efficient battery thermal management systems (BTMSs) to prevent overheating and safety risks. This study explores composite phase change materials (CPCMs) enhanced with silicon dioxide (SiO2) nanoparticles to develop a hybrid BTMS capable of maintaining thermal stability under high-load conditions. Three phase change materials—paraffin, myristic acid, and sodium acetate trihydrate—were evaluated experimentally, with myristic acid containing 1% by weight SiO2 exhibiting optimal performance with 24% increased phase transition duration (838 s versus 676 s) and 18% enhanced thermal conductivity compared to pure PCM. Controlled heating simulated battery discharge, while computational fluid dynamics analyzed temperature and velocity distributions in pouch battery configurations with varying packing densities (3–42 units). Simulations revealed that 42-unit configurations reduced maximum temperatures by 8.2°C compared to 3-unit designs. Experimental validation demonstrated that CPCM-integrated systems reduced peak temperatures by 6.4–7.6°C (8–9% reduction) compared to liquid cooling alone, while maintaining thermal gradients below 3.8°C versus 5.9°C for coolant-only configurations. Container geometry (circular vs. square) showed minimal influence on thermal performance (0.8°C difference). These findings demonstrate that minimal nanoparticle loading (1% by weight) achieves cost-effective thermal management, and that CPCM integration significantly improves temperature uniformity. The aluminum alloy container design provides structural stability under thermal cycling. This work establishes a validated methodology for hybrid cooling systems applicable to next-generation lithium-ion battery thermal management.