Heat sink for power module

A power module comprising:

• a power device;
• and
• a heat sink to which heat generated by the power device is transmitted, the heat sink including:
• a refrigerant passage in which a cooling medium that dissipates the heat generated by the power device flows, the refrigerant passage is defined by a surface and a backside, and the power device is disposed in proximity to said surface;
• and
• a corrugated fin body arranged in the refrigerant passage,
• wherein the corrugated fin body has crests and troughs that extend in a parallel manner and side walls each of which connects a corresponding one of the crests with an adjacent one of the troughs, the crests are joined to the surface, and the troughs are joined to the backside, wherein each adjacent pair of the side walls and the corresponding one of the crests or the adjacent one of the troughs arranged between the each adjacent pair of side walls form a fin,
• wherein a first louver is formed in one of the each adjacent pair of the side walls, a second louver is formed in another of the each adjacent pair of the side walls, and wherein the first and second louvers operate to, at least, rotate the cooling medium flowing in the fin to the other side wall past the corresponding one of the crests or the adjacent one of the troughs.