Method for producing membrane electrode assembly

Abstract

The present invention relates to a Membrane Electrode Assembly (MEA) which significantly enhances power density as well as structural reliability and method for producing the same. More specifically, it relates to the Membrane Electrode Assembly which has a plurality of protuberances and method for producing the same. The present invention involves making supporting bodies to have a plurality of protuberances on one side of the supporting bodies, forming a catalyst layer on one side of the supporting bodies having the protuberances, interposing a polymer-electrolyte-membrane between the supporting bodies, aligning the supporting bodies for the protuberances to engage each other; and hot-pressing the aligned supporting bodies. The present invention can increase the area of a three-phase boundary in which oxidation-reduction reaction of hydrogen and oxygen occurs and decrease resistance to ion conduction; consequently fuel cells have the characteristic of a large output of power density.

1 - 25 . (canceled)  
     
     
         26 . A method for producing a membrane electrode assembly generating an electric current by electric chemical reaction comprising the step of: 
 forming a plurality of protuberances on one side of supporting bodies, wherein a three phase boundary corresponding to said protuberances is formed.    
     
     
         27 . The method of  claim 26 , wherein the shape of said protuberances is at least one selected from quadrangular prism, triangular prism, trapezoid prism, hexahedron, and quadrangular prismoid.  
     
     
         28 . The method of  claim 26 , wherein an aspect ratio of said protuberances is from 0.01 to 6.  
     
     
         29 . The method of  claim 26 , wherein an aspect ratio of said protuberances is from 0.5 to 3.  
     
     
         30 . The method of  claim 26 , wherein a width of said protuberances is from 50 μm to 500 μm.  
     
     
         31 . The method of  claim 26 , wherein a width of said protuberances is from 100 μm to 200 μm.  
     
     
         32 . The method of  claim 26 , wherein 
 the step of making said supporting bodies to have a plurality of said protuberances on one side of said supporting bodies further comprises the steps of:    coating one side of said supporting bodies with a dry film;    exposing the one side of said supporting bodies;    developing said dry film; and    etching the one side of said supporting bodies physically.    
     
     
         33 . The method of  claim 32 , wherein said dry film is developed by a spraying developer.  
     
     
         34 . The method of  claim 32 , wherein said supporting bodies are etched by a sand blaster.  
     
     
         35 . The method of  claim 32 , wherein the etching depth is hundreds of micrometers.  
     
     
         36 . The method of  claim 32  further comprising the step of combining a plate to the one side of said supporting bodies on which said protuberances is formed.  
     
     
         37 . The method of  claim 27 , wherein the step of making said protuberances on one side of said supporting bodies is performed by press processing.  
     
     
         38 - 45 . (canceled)