Method of forming a gasket assembly for a PEM fuel cell assembly

Abstract

A thermoplastic carrier sheet is die-cut to have a size and shape matching that of a PEM bipolar plate. A plurality of holes are punched in the carrier sheet in the pattern of gasket beading to be formed subsequently. In a mold, liquid gasket resin fills the mold on both sides of the carrier sheet to form the gasket, flowing through the holes in the sheet and thereby causing the gasket to become mechanically attached to the sheet. A carrier element having a flange portion substantially identical with the outer profile of the bipolar plates is laminated to the sheet edge. During assembly of a fuel cell, the carrier element automatically positions the gasket correctly on the plate and prevents the gasket from twisting or shifting. In a currently preferred embodiment, a membrane electrode assembly is attached within an appropriate opening in the carrier sheet.

1 . A method for forming a gasket assembly for use in sealing bipolar plates in a proton exchange fuel cell assembly, comprising the steps of: 
 a) forming a carrier sheet in a general shape of a bipolar plate;    b) forming a plurality of holes in said carrier sheet in one or more regions of said sheet for receiving gasketing material;    c) inserting said carrier sheet into a mold; and    d) entering said gasketing material into said mold to form one or more gasket elements extending away from at least one surface of said carrier sheet and extending into at least one of said holes in said sheet.    
     
     
         2 . A method in accordance with  claim 1  wherein first and second gasket elements are formed on opposite sides of said carrier sheets and are joined through said holes.  
     
     
         3 . A method in accordance with  claim 1  comprising the further steps of: 
 a) forming a carrier element for said carrier sheet and gasket elements, and    b) attaching said carrier element to said carrier sheet.    
     
     
         4 . A method in accordance with  claim 3  wherein said carrier element has a flange portion substantially identical with an edge profile of said bipolar plates.  
     
     
         5 . A method in accordance with  claim 3  wherein said carrier element further comprises a spacer portion extendable between said bipolar plates for limiting the compression of said one or more gasket elements.  
     
     
         6 . A method in accordance with  claim 1  further comprising the step of attaching a membrane electrode assembly to said carrier sheet.  
     
     
         7 . A gasket assembly for sealing bipolar plates in a proton exchange fuel cell assembly, said gasket assembly being formed in accordance with  claim 1 .  
     
     
         8 - 11 . (canceled)