Electrochemical cell stack

An electrochemical cell stack comprising:

• bipolar plates;
• a plurality of electrochemical cells separated from one another by the bipolar plates, each electrochemical cell includes two half-cells, a membrane, and a support frame, the membrane is surrounded by the support frame and arranged between the two half-cells,
• a porous transport layer is disposed in each half-cell,
• wherein the support frame, viewed in cross-section, includes a stepped shape having at least two mutually adjoining cross-section regions of different widths, one edge of the membrane lying in a step formed by the two cross-section regions, and the porous transport layer of one of the two half-cells extending as a compressive-force-transmitting element into the step, and
• wherein the support frame comprises at least one sealing arrangement of an electrically insulating sealing material injection-molded onto the support frame, the at least one sealing arrangement comprising at least three sealing regions each having at least one sealing lip, the at least three sealing regions include a first sealing region and a second sealing region, which belong to the narrower of the two cross-section regions facing the membrane and each contact exactly one bipolar plate, and a third sealing region, which is disposed on a side of the support frame facing away from the step and borders an opening of the support frame for guiding through of media and in this case contacts the bipolar plates against which the first and second sealing regions bear.