Stack of electrochemical cells

An electrochemical cell stack comprises alternately arranged membrane electrode units and separator plates (1) with channel regions (3) for the supply and removal of reactant or oxidant fluid at the membrane electrode unit. The separator plates have on one side a surface structure of channels (5) and intermediate webs (4) and on the other side a negative structure of this. The separator plates have a channel region offset from the geometric center (M) so that on stacking the separator plates with adjacent plates rotated by 180 degrees to the normal (F) the separator plates lie on top of each other so that external forces referred to the membrane electrode assembly between the separator plates are transferred free of bending moments. The channel region is offset perpendicular to at least one channel direction. The distance by which the channel region is offset corresponds to half the distance between the center of the channel and the center of the web or a whole number multiple of the distance. The channel region has the same number of channel and webs. The cross-sections of the channels and webs are different.