Abstract: A bipolar plate for a fuel cell is provided. The bipolar plate having flow channels for oxidant gas; said flow channels for oxidant gas comprising one or more grooves each representing a serpentine path; wherein each said serpentine path independently comprises N consecutive legs L1, L2, . . . LN; connected to each other by N?1 consecutive turn sections, T1, T2, . . . TN-1; wherein each leg L1, L2, . . . LN-1 being lengthwise separated from its consecutive leg L2, L3, . . . LN by a wall section, W1, W2, . . . WN-1; wherein each turn section representing a 180° change of flow direction of oxidant gas; wherein N is an odd integer of 3 or more; and wherein one or more of the wall sections W1, W2, . . . WN-1 independently comprise one or more by-pass channels for allowing oxidant gas to flow via a short cut from one leg Lx to its consecutive leg Lx+1; 1?x?N?1; thereby by passing a part of the leg Lx and a part of the leg Lx+1. Furthermore, a cooling plate having a similar design is provided.

Abstract: A bipolar plate (1) in combination with a sealant (50, 70) for a PEM fuel cell, wherein the bipolar plate (1) has an anode side with first flow channels (20) for transport of a proton-donating fuel or a cathode side with second flow channels (12) for transport of proton-accepting fluid, or both, wherein a sealant (50, 70) is provided parallel with the bipolar plate (1) for sealing the bipolar plate against an adjacent electrolytic membrane (40). The sealant (50, 70) has fluid channels (54a, 54b, 74a, 74b) across the sealant (50, 70) for transport of proton-donating fuel or proton-accepting fluid, respectively, across the sealant and along the bipolar plate.