A battery system having first and second battery cells and a cooling fin disposed between the first and second battery cells is provided. The cooling fin receives heat energy from the first and second battery cells and transitions a two-phase refrigerant into a gaseous refrigerant within an internal flow path. The compressor pumps the gaseous refrigerant into a condenser. The condenser transitions the gaseous refrigerant into the liquid refrigerant by extracting heat energy from the gaseous refrigerant.