Compliant electrical contacts for fuel cell use

Abstract

This invention concerns improvements in fuel cell fabrication. Arrays of independent acting compliant electrical contacts are incorporated within a fuel cell which improve fuel cell Bi Polar Separator Plate (bipolar separator plate) which improve fuel cell operation by creating uniform and intimate electrical contact with the adjacent membrane electrode assembly (Membrane electrode assembly). These compliant electrical contacts provide substantial uniform internal pressure distribution and substantially uniform electrical contact. In one embodiment, the array of compliant electrical contacts are in the form of a plurality of metal springs of various configurations which are electrically and mechanical contacted to a conducting base plate. In another embodiment the array of compliant electrical contacts are in the form of a plurality of small metal pins or rods which are electrically and mechanically contacted to a conducting base plate.

We claim:  
     
         1 . An array of independently acting compliant electrical contacts within a fuel cell electrode which improve fuel cell operation and performance by providing substantially increased and optimized surface area for increased electrical contact between the compliant contact attached to the conducting plate and bipolar separator plate and membrane electrode assembly, substantial uniform internal compressive loads and distribution resulting from the independent action of the compliant electrical contacts when the fuel cell stack is compressed.  
     
     
         2 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of inverted V shaped metal springs or other configurations as described herein which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         3 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of inverted V shaped metal arch springs having a cantilevered portion which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         4 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of inverted rounded metal arch springs having a cantilevered portion which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         5 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of inverted flat contact surface shaped metal arch springs having a cantilevered portion which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         6 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of omega shaped metal springs with multiple deflection areas and multiple contact areas and which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         7 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of omega shaped metal springs with multiple deflection areas and multiple contact areas, in strip form, and which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         8 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of “S” shaped springs with right angle contact area with multiple deflection areas and having a flat area and which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         9 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of “S” shaped springs with radiused right angle contact area, and interlocking and alignment/locating features with multiple deflection areas, and having a flat area and which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         10 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of “S” shaped springs with radiused right angle contact area, and interlocking and alignment/locating features with multiple deflection areas, in strip form, and having a flat area and which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         11 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of “Z” shaped springs with right angle contact area, and right angle mounting area, with multiple deflection areas and which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         12 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of modified omega shaped springs with multiple deflection areas and a slight break in the top curve crating a slight peak and which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         13 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of modified omega shaped metal springs with multiple deflection areas and a slight break in the top curve crating a slight peak, in strip form and which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         14 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of modified omega shaped metal springs with multiple deflection areas and a smooth crown in the top curve leaving no peak and which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         15 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of modified omega shaped metal springs with multiple deflection areas and a smooth crown in the curve leaving no peak, in strip form and which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         16 . The array of  claim 1  individually or in strip form, wherein the strips form ventilated horizontal channels or passages to aid in air/oxygen flow to the fuel cell membrane and aid in the operation of the fuel cell.  
     
     
         17 . The array of  claim 1  individually or in strip form, wherein the strips form vertical ventilated channels or passageways (chimneys) to aid in air/oxygen flow to the fuel cell membrane and aid the operation of the fuel cell.  
     
     
         18 . The array of  claim 1  and all of its embodiments, wherein the combination of the compliant electrical contacts and the conducting base plate and bipolar separator plate create a uniform thermal gradient for stable fuel cell operation and increased life.  
     
     
         19 . The array of  claim 1  wherein the compressive forces developed by the individual springs withing the cell that are accommodated by the compliant electrical contacts is usually between about 0.10 lb and 50 lb per spring leaf or finger depending on the configuration as described herein.  
     
     
         20 . The array in  claim 1  wherein the compliant electrical contacts range in cross section from 0.030 in. to 3.00 in., but are not limited by size or shape.  
     
     
         21 . The array of  claim 1  wherein the spacing between compliant electrical contacts range from 0.005 in. to 2.0 in., but are not limited by size or shape.  
     
     
         22 . The array in  claim 1  wherein the compliant electrical contacts range in length (across the fuel cell plate from 0.10 in. to 100.0 in., but are not limited by size or shape.  
     
     
         23 . The conductive plates and bipolar separator plates that the array in  claim 1  attach to are as small as ¼ in.×¼ in. for very small, light, portable devices such as video cameras, movie cameras, etc. to large sizes 3 to 30 square meters required for homes, businesses, large buildings, or small cities.  
     
     
         24 . The array of  claim 1  wherein the compliant electrical contacts are in the form of a plurality of small metal pins which are electrically contacted and connected mechanically, metallurgically or combinations thereof to a conducting base plate or bipolar separator plate.  
     
     
         25 . The array of  claim 1  wherein the plurality of compliant electrical contacts form a regular patterned arrangement having a substantially uniform distance between contact points (surfaces). In another aspect, the pluralities of compliant electrical contacts (metal springs) have an irregular patterned arrangement and substantially non-uniform distance between contact points (surfaces).  
     
     
         26 . The array of  claim 24  wherein the tips of the small metal pins in to contact the adjacent electrode have a head similar to a nail head.  
     
     
         27 . The array of  claim 24  wherein the plurality of metal pins form a regular patterned arrangement having a substantially uniform distance between pins.  
     
     
         28 . The compliant electrical contacts of  claim 24  are selected from those shown in FIGS. 5, 6,  7 ,  8 ,  9 A to  9 O or  10 .  
     
     
         29 . The array of  claim 1  wherein the bipolar separator plates are selected from, very thin, very flexible metal bipolar separator plates (about 0.001 to 0.500 in. thick).  
     
     
         30 . The compliant electrical contacts (springs) wherein the thickness of the shaped metal strip is between about 0.001 in. and 0.090 in.  
     
     
         31 . The individual compliant electrical contact wherein the width of the shaped metal strip is between about 0.020 in. and 1.0 in.  
     
     
         32 . The compliant electrical contact of  claim 24  wherein the height of the configures metal strip from base to electrical contact point(s) surface is between about 0.010 in. and 2.0 in., but not to be limited by size or shape.  
     
     
         33 . The array of  claim 24  wherein the compliant electrical contacts are comprised of alloys of iron, copper, gold, silver, platinum, aluminum, nickel, chromium, and combinations thereof.  
     
     
         34 . The array of  claim 24  wherein compliant electrical contacts are electrically, mechanically and/or metallurgically contacted and connected to the conducting plate or bipolar separator plate via soldering, brazing, welding, conductive adhesives, riveting, bolting, crimping or other metallurgical or mechanical method of attachment.  
     
     
         35 . The array of  claim 24  wherein the blank for the compliant electrical contacts are fabricated by etching, machining, stamping, fine blanking, coining, die cutting, extruding, laser cutting, hydro-forming, electro discharge machining, or other suitable method of fabrication.  
     
     
         36 . The array of  claim 24  wherein the compliant electrical contacts are formed into the various shapes and configurations described herein by etching, machining, stamping, fine blanking, coining, dies cutting, extruding, laser cutting, hydro-forming, electro discharge machining or other suitable method of fabrication or forming.  
     
     
         37 . The conductive plates which the array of  claim 24  are connected to are fabricated by etching, stamping, machining, fine blanking, coining, die cutting, extruding, laser cutting, roll forming, hydro-forming or other suitable method of fabrication.