The invention aims at providing a fuel cell capable of highly efficient and stable operation, by eliminating the flooding caused by condensed water and generated water during low-load operation, and by inhibiting the increase in the pressure drop at high loads. A fuel cell that does not flood, particularly during low-load operation, in accordance with the invention is realized by forming multiple independent gas flow channels having independent inlet-side and outlet-side manifold holes in the separator surface, and by connecting these in series or in parallel.
This connection can be obtained through switching means characterised in that:
the inlets and outlets of such switchable channel means are maintained in both operational modes in a manner that in both operational modes the switchable channel means are fed by their fluid in the same direction of circulation.