A numerical simulation of the heat dissipation performance in photovoltaic (PV) cells with phase change material (PCM) for cooling is performed by COMSOL Multiphysics. A comparative analysis of two T-shaped fin designs in PCM heat sinks is conducted to evaluate their impact on the cooling performance of PV panels. The findings indicate that a 180° T-shaped fin design substantially outperforms a cavity without fin design, reducing the PV cell average temperature by up to 15.1 K and enhancing electrical efficiency by 1.36 %. Further optimization of distal fin distance and secondary length reveals that temperature uniformity and photovoltaic efficiency can be improved, achieving a maximum electrical efficiency increase of 1.40 % and a temperature uniformity enhancement of 71.0 %. Detailed analysis underscores the critical role of the distal fin distance (Scheme 1) in temperature control and PCM convection, highlighting its importance in the design process. In contrast, numerical results of the alternative fin layout (Scheme 2) reveal its unsuitability for PV cooling applications.