This paper presents the outcomes of an experimental investigation focusing on the performance of finned heat dissipator incorporating phase change materials for the thermal management of cylindrical lithium-ion batteries (LIBs). The selected phase change material (PCM) in this study is n-eicosane, strategically positioned within an aluminium heat sink. The aluminium serves as a thermal conductivity booster (TCB), addressing the inherently low thermal conductivity of the PCM. The heat sink serves a dual purpose, functioning as both an energy storage unit and a module for spreading heat. Pin fin and plate fin configurations, each with an identical volume fraction of the TCB, are employed. The study delves into the impact of different fin types on operational duration under various power levels (ranging from 8 to 20 W in steps of 3 W), target temperature, and the time frame of the latent heating phase. The findings underscore that incorporating fins into heat sinks filled with PCM significantly enhances the operational performance of LIBs and case 4 (pin fin heat sink filled with PCM) shows superior thermal performance among the heat sinks considered.