Patent ID: 8012647

Claim:
A membrane electrode unit comprising: a) two electrochemically active electrodes; the electrochemically active electrodes being a first electrode and a second electrode; the electrochemically active electrodes are separated by a polymer electrolyte membrane comprising a polyazole doped with an acid; the polymer electrolyte membrane having a front side and a rear side; the front side of the polymer electrolyte membrane is in contact with the first electrode; wherein the first electrode covering partially or completely the front side of the polymer electrolyte membrane; the rear side of the polymer electrolyte membrane is in contact with the second electrode; wherein the second electrode covering partially or completely the rear side of the polymer electrolyte membrane; the polymer electrolyte membrane having one or more cut-outs; b) a sealing material; the sealing material being on the front side and the rear side of the polymer electrolyte membrane, the rear side sealing material having a plurality of protrusion, each protrusion having a height at least as great as a thickness of the membrane; wherein the protrusions of the sealing material on the rear side of the polymer electrolyte membrane are in contact with the sealing material on the front side of the polymer electrolyte membrane; characterized in that the polymer electrolyte membrane having one or more cut-outs and the protrusions of the sealing material on the rear side of the polymer electrolyte membrane are in contact with the sealing material on the front side of the polymer electrolyte membrane through the cut-outs, and the first electrode and the sealing material on the front side of the polymer electrolyte membrane defining a gap therebetween, and the second electrode and the sealing material on the rear side of the polymer electrolyte membrane defining a gap therebetween.