Patent ID: 8206870

Claim:
A membrane electrode assembly comprising a) two electrochemically active electrodes ( 1 , 3 ) separated by a polymer electrolyte membrane ( 5 ) having a front and a back wherein the surfaces of the polymer electrolyte membrane ( 5 ) are in contact with the electrodes ( 1 , 3 ) in such a way that the first electrode ( 1 ) partially or totally covers the front of the polymer electrolyte membrane ( 5 ) and the second electrode ( 3 ) partially or totally covers the back of the polymer electrolyte membrane ( 5 ); b) two gasket layers ( 15 , 17 ) made of a first gasket film wherein the first gasket layer ( 15 ) is a frame which partially covers the front of the polymer electrolyte membrane ( 5 ) and the first electrode ( 1 ) and has a front, and the second gasket layer ( 17 ) is a frame which partially covers the back of the polymer electrolyte membrane ( 5 ) and the second electrode ( 3 ) and has a back; characterized in that the membrane electrode assembly also comprises a second gasket material ( 7 , 9 ) on the front of the first gasket layer ( 15 ) and on the back of the second gasket layer ( 17 ); each of the gasket layers ( 15 , 17 ) forming a frame on the polymer electrolyte membrane ( 5 ) and comprises at least one recess ( 11 , 12 ); the second gasket material ( 7 ) on the front of first gasket layer ( 15 ) is in contact with the second gasket material ( 9 ) on the back of the second gasket layer ( 17 ) through the at least one recess ( 11 ) in the first gasket layer ( 15 ) and the at least one recess ( 12 ) in the second gasket layer ( 17 ); the polymer electrolyte membrane ( 5 ) is doped with an acid and comprises polyazoles; the two gasket layers ( 15 , 17 ) extend beyond the membrane ( 5 ), are in flat contact with one another, and are welded to one another.