Bipolar plate for a fuel cell

A bipolar plate for a fuel cell, the bipolar plate comprises a plurality of groove type gas channels (22) substantially parallel with one another, each of the gas channels has a cross section area defined by the walls thereof and an opening (26), each of the openings is provided with a reducing device (28) to reduce the cross section area in the vicinity of the opening. This invention thus can increase the pressure difference between the inlet and outlet of the gas channels. Therefore, the gas channels of the bipolar plate will not be clogged by water droplets and the fuel cell can be operated with high efficiency.