Advanced phase change materials for safe battery thermal management in electric vehicles

Phase change materials are promising for improving energy efficiency and enabling low-carbon electrification, but their limited thermal conductivity constrains battery thermal management. This study develops and evaluates nano-enhanced phase change materials by dispersing graphene nanoplatelets and integrates the resulting composites into a thermal management system for lithium-ion cells used in electric vehicles. Thermophysical properties were characterized across graphene nanoplatelets loadings of 0–4 wt%, and a Pareto-based multi-objective optimization identified compositions that maximize thermal conductivity while preserving thermal energy-storage capacity and stability. At a charge rate of 1.25C, the optimized nano-enhanced phase change materials reduce the maximum cell temperature from 51.6 °C (0 wt% graphene nanoplatelets) to 28.1 °C (4 wt%), corresponding to a 45.5% reduction. Similarly, during a discharge rate of 2.5C, it drops from 67.2 °C to 41.7 °C, representing a 38.0% reduction in maximum cell temperature. The nano-enhanced material improves heat dissipation and spatial temperature uniformity, with only a modest decrease in latent heat. These results outline a systematic, data-driven pathway to scalable, material-optimized thermal management for batteries that extends service life, enhances safety, and supports the sustainable deployment of electric vehicles and next-generation energy storage systems. • Nano-enhanced phase change materials improve BTMS energy and thermal performance • Graphene nanoplatelet PCMs markedly reduce peak cell temperature and uniformity • Predictive models and NSGA-II multi-objective optimization guide optimal NePCM design • Practical PCM sizing demonstrates a compact, passive solution for EV battery cooling