The Battery chargers are an important component in electric and plug-in hybrid vehicles and various other clean energy systems. The thermal management in the battery charger is a crucial aspect that influences its overall performance and cyclic stability. Passive cooling technology using heat sinks is preferred in developing battery chargers due to its reliability, quietness, and efficiency. In the present work, new hybrid passive heat sinks with various fin geometries namely inclined interrupted fins, pin fins, and straight interrupted fins, have been developed by adding a phase change material layer to passively cooled bare fin heat sinks. The developed heat sinks have the same geometric footprint as that of the battery charger; IC650 was built by the industrial partner of the project Delta-Q Technologies. Simulations were carried out to analyze the effects of PCM quantities for thermal loads on the heating-cooling performance of the HPHS using Ansys fluent 19.1 commercially available software to validate the experimental results from the literature study. Inclined interrupted fin design found more effective in terms of thermal performance among all considered configurations.