Rajesh Nasinathan, Kamatchi Rajaram
ABSTRACT Thermal management of lithium‐ion batteries (LIBs) faces challenges in ensuring optimal performance, safety, and lifespan due to excessive heat generation during high power discharging cycles. Recently, nano‐enhanced phase change materials have been considered as sustainable passive cooling techniques to enhance the LIBs' performance. Unlike previous studies that focused on single or binary filler systems, this work introduces a novel multicomponent composite phase change material (CPCM) by incorporating varying loadings of expanded graphite (EG), hexagonal boron nitride nanosheets (h‐BNNSs), MXene (Ti 3 C 2 T x ), and epoxy resin (ER) into the matrix of paraffin wax/polyethylene glycol/lauric acid to synergistically enhance thermal performance. Three different CPCM samples (CPCM 1, CPCM 2, and CPCM 3) are synthesized and characterized by XRD, FTIR, and SEM. Thermal properties are evaluated by DSC and TGA. Among all, CPCM 1 results in a maximum latent heat of 153.28 J/g and thermal conductivity of 1.26 W/m K in addition to superior antileakage performance. Additionally, CPCM 1 is applied to a 4S6P LIB module and tested under 1C, 2C, and 3C discharge rates. At 3C, the peak temperature remained within the safe threshold of 50°C with a temperature variation of just 1.91°C between the cells. The battery module retained a capacity of 1207.56 mAh over 50 discharge cycles. The results highlight the potential of the developed CPCM as an effective, lightweight, and energy‐efficient passive cooling solution for next‐generation LIB thermal management systems.