Experimental investigation of gallium-based composite PCM for battery thermal management applications

Efficient thermal management is essential for the safety and performance of battery systems, extending their lifespan and reducing the risk of thermal runaway. This study investigates the use of gallium-based composite phase-change materials (CPCMs) for managing the thermal load of lithium-ion batteries (LIBs) during rapid discharge cycles. We synthesized CPCMs by integrating paraffin (PA) and gallium (Ga) in varying ratios, ensuring a consistent inclusion of 5% expanded graphite (EG) for structural stability. Advanced analytical techniques characterized the thermal properties and phase-transition behaviors of CPCMs. The results show that incorporating Ga significantly improves the thermal conductivity and stability of the composites, while also altering their crystallization and melting dynamics. When applied to a cylindrical LIB, CPCMs with higher Ga content demonstrated lower melting points and superior thermal management capabilities. Specifically, a composition of 76 wt% PA and 19 wt% Ga (CPCM3 at a 4:1 ratio) reduced the battery's surface temperature by 39% at a 4 C discharge rate, relative to a standard PA and EG-based composite PCM. These findings underscore the potential of Ga-based CPCMs to enhance both the thermal performance and safety of LIBs under high-rate cycling conditions.