Impact of housing inclination on a passive battery thermal management system using NPCM of n-octadecane and silver nanoparticles

Effective thermal management remains a critical challenge for lithium-ion batteries (LIBs), as inadequate cooling can compromise performance and safety. While phase change materials (PCMs) offer passive cooling, their low thermal conductivity limits their efficacy, and the influence of housing orientation on performance is rarely addressed. This computational fluid dynamics (CFD) study investigates a passive battery thermal management system (BTMS) for a cylindrical LIB, utilizing a nano-enhanced PCM (NPCM) composed of n-octadecane and silver nanoparticles (SNPs) within a cylindrical housing. The study uniquely focuses on the impact of housing inclination angle (θ = 0° vertical to 90° horizontal). The results demonstrate that orienting the housing from vertical to horizontal increases NPCM melting by 10% while raising the battery's maximum temperature (T b ) by only 0.68 K. Furthermore, adding 3% SNPs enhances thermal conductivity, reducing the average melting fraction (AMF) by 20% and lowering T b by 1.43 K. This research provides crucial quantitative insights for designing orientation-sensitive, high-performance passive BTMS for electric vehicles and portable electronics.