Fuel cell stack having a featured interconnect element

Abstract

An interconnect element for electrically connecting an anode and a cathode in adjacent fuel cells in a fuel cell stack, wherein said interconnect element has at least one featured surface including dimples, bosses, and/or pins arranged in a two-dimensional pattern. Preferably, both surfaces are featured, as by mechanical dimpling, embossing, or chemical etching, so that protrusions of the interconnect surface extend into either or both of the adjacent gas flow spaces to make electrical contact with the surfaces of the anode and cathode. This permits conduction of heat from the anode. The protrusions create turbulence in gas flowing through the flow spaces, which increases hydrogen consumption at the anode and hence electric output of the cell.

What is claimed is:  
     
         1 . An interconnect element for electrically connecting an anode and a cathode in adjacent fuel cells in a fuel cell stack, wherein said interconnect element has at least one featured surface.  
     
     
         2 . An interconnect element in accordance with  claim 1  wherein said element has featured surfaces on opposite sides of said element.  
     
     
         3 . An interconnect element in accordance with  claim 2  wherein features of said featured surfaces include bosses and dimples.  
     
     
         4 . An interconnect element in accordance with  claim 3  wherein said bosses and dimples are formed in said element by embossing of an unfeatured planar blank.  
     
     
         5 . An interconnect element in accordance with  claim 2  wherein features of said featured surfaces include only bosses.  
     
     
         6 . An interconnect element in accordance with  claim 5  wherein said bosses are formed in said element by a process selected from the group consisting of injection molding and casting.  
     
     
         7 . An interconnect element in accordance with  claim 2  wherein said features of said featured surfaces include pins.  
     
     
         8 . An interconnect element in accordance with  claim 7  wherein said pins are formed in said element by etching of an unfeatured planar blank.  
     
     
         9 . An interconnect element in accordance with  claim 1  wherein features of said featured surface are distributed in a two-dimensional pattern.  
     
     
         10 . An interconnect element in accordance with  claim 9  wherein said pattern is regular.  
     
     
         11 . An interconnect element in accordance with  claim 9  wherein said pattern is irregular.  
     
     
         12 . A fuel cell stack for generating an electric current, comprising: 
 a) an anode in a first fuel cell;    b) a cathode in a second fuel cell adjacent said first fuel cell in said stack; and    c) an interconnect element disposed between said anode and said cathode and having features extending above at least one surface toward a one of said anode and said cathode.    
     
     
         13 . A fuel cell stack in accordance with  claim 12  wherein said interconnect element includes features extending toward both of said anode and said cathode.  
     
     
         14 . A fuel cell stack in accordance with  claim 13  wherein said features are in electrical contact with said anode and said cathode.  
     
     
         15 . An automotive vehicle including a fuel cell stack for generating an electric current, wherein said fuel cell stack comprises: 
 a) an anode in a first fuel cell;    b) a cathode in a second fuel cell adjacent said first fuel cell in said stack; and    c) an interconnect element disposed between said anode and said cathode, said interconnect element having features extending from surfaces thereof, said features being in electrical contact with said anode and said cathode.