Bipolar collectors for a fuel cell of the PEM type

Abstract

A bipolar collector-heat exchanger is shown which combines, at the same time, a main structure made of an electronically and thermally conducting material, discrete collection of the charges and the heat, carried out by metal contacts which are distributed uniformly at the surface of the electrodes and penetrate into the main structure, but which do not pass fully through it, and the use of non-conductive open structures which homogenise the flow of the gaseous reactants.

1 . Bipolar collector-heat exchanger, which combines, at the same time: 
 a main structure made of an electronically and thermally conducting material,    discrete collection of the charges and the heat, carried out by metal contacts which are distributed uniformly at the surface of the electrodes and penetrate into the main structure, but which do not pass fully through it, and    the use of non-conductive open structures which homogenise the flow of the gaseous reactants.    
     
     
         2 . Bipolar collector-heat exchanger according to  claim 1 , characterised in that the electronically and thermally conductive main structure consists of two parts, at least one of which comprises, on one of its faces, ribs which permit the circulation of a heat-exchange fluid.  
     
     
         3 . Bipolar collector-heat exchanger according to  claim 2 , characterised in that, in the event that both parts of the main structure comprise ribs on one of their faces, the said faces are juxtaposed during their assembly in order to create channels which permit circulation of the heat-exchanged fluid.  
     
     
         4 . Bipolar collector-heat exchanger according to  claim 1 , characterised in that the metal contacts are metal needles which penetrate into the protruding parts contained between the channels intended for circulation of the heat-exchange fluid, their end being located between 0.4 and 0.9 mm from the plane separating the two parts constituting the main structure.  
     
     
         5 . Bipolar collector-heat exchanger according to  claim 4 , characterised in that the needles penetrate into the electrodes by a depth of between 0.1 and 0.2 mm, and they are distributed uniformly in square or rectangular patterns.  
     
     
         6 . Bipolar collector-heat exchanger according to  claim 1 , characterised in that a space, whose thickness is between 0.8 and 2 mm and which is filled with a non-conductive open structure, is made between each electrode and the surface of the collector-exchanger, with the aid of studs placed on the outer faces of the two parts with constitute the main structure.  
     
     
         7 . Bipolar collector-heat exchanger according to  claim 6 , characterised in that the non-conductive open structure is a polymer foam whose surface preferably has a hydrophobic nature.  
     
     
         8 . Bipolar collector-heat exchanger according to  claim 6 , characterised in that the non-conductive open structure is a foam whose core consists of a heat-conducting metallic material and which is coated with an anticorrosion layer having a hydrophobic nature.  
     
     
         9 . Bipolar collector-heat exchanger according to  claim 6 , characterized in that the non-conductive open structure consists of a polyer mesh which is open longitudinally and whose surface preferably has a hydrophobic nature.  
     
     
         10 . Bipolar collector-heat exchanger according to  claim 1 , charactersed in that the electronically and thermally conductive main structure consists of two parts, at least one of which comprises, further to the studs which are made on one of their faces and are used to define the space between the electrodes and the collector-exchanger, on their other face, cylindrical studs with a height of between 0.5 and 2 mm, having a diameter of between 3 and 10 mm. The two juxtaposed parts create a space intended for circulation of the heat-exchange fluid.  
     
     
         11 . Bipolar collector-heat exchanger according to  claim 10 , characterised in that the cylindrical studs which are used to make a space intended for circulation of the heat-exchange fluid are distributed uniformly at the surface of the collector-exchanger, in a number such that the total area of their cross section occupies at least 40% of the apparent area of the electrodes.  
     
     
         12 . Bipolar collector-heat exchanger according to  claim 10 , characterised in that the cylindrical studs which are used to make a space intended for circulation of the heat-exchange fluid are distributed uniformly at the surface of the collector-exchanger, in a number such that the total area of their cross section is less than 10% of the apparent area of the electrodes.  
     
     
         13 . Bipolar collector-heat exchanger according to  claim 12 , characterised in that the space intended for circtulation of the heat-exchange fluid is filled with an open-structured foam consisting of a metallic material which is a good conductor of heat and electricity, the strands of which are in contact with the walls of the main structure.  
     
     
         14 . Bipolar collector-heat exchanger according to  claim 13 , characterised in that the constitutent material of the foam is made of copper or nickel.  
     
     
         15 . Bipolar collector-heat exchanger according to claims  10  and  13 , characterised in that the walls in contact with the foam are coated with a thin electronically conductive layer such as a metal, a metal alloy or conductive varnish.  
     
     
         16 . Bipolar collector-heat exchanger according to claims  1  and  10 , characterised in that the metal contacts which carry out the discrete collection of the charges and the heat are metal needles which penetrate partially into the main structure, their and being located between 0.4 and 0.9 mm from the plane separating the two parts constituting the main structure.  
     
     
         17 . Bipolar collector-heat exchanger according to  claim 12 , characterised in that the needles penetrate into the electrodes by a depth of between 0.1 and 0.2 mm, and they are distributed uniformly in square, rectangular or equilateral-triangular patterns.  
     
     
         18 . Bipolar collector-heat exchanger, which combines, at the same time: 
 a main structure made of an electronically and thermally conducting material,    discrete collection of the charges and the heat, carried out by metal contacts which are distributed uniformly at the surface of the electrodes and penetrate into the main structure, but which do not pass fully through it, and    the use of non-conductive open structures which homogenise the flow of the gaseous reactants.    
     
     
         19 . Bipolar collector-heat exchanger according to  claim 18 , wherein the electronically and thermally conductive main structure consists of two parts, at least one of which comprises, on one of its faces, ribs which permit the circulation of a heat-exchange fluid.  
     
     
         20 . Bipolar collector-heat exchanger according to  claim 19 , wherein in the event that both parts of the main structure comprise ribs on one of their faces, the said faces are juxtaposed during their assembly in order to create channels which permit circulation of the heat-exchange fluid.  
     
     
         21 . Bipolar collector-heat exchanger according to  claim 18 , wherein the metal contacts are metal needles which penetrate into the protruding parts contained between the channels intended for circulation of the heat-exchange fluid, their end being located between 0.4 and 0.9 mm from the plane separating the two parts constituting the main structure.  
     
     
         22 . Bipolar collector-heat exchanger according to  claim 21 , wherein the needles penetrate into the electrodes by a depth of between 0.1 and 0.2 mm, and they are distributed uniformly in square or rectangular patterns.  
     
     
         23 . Bipolar collector-heat exchanger according to  claim 18 , wherein a space, whose thickness is between 0.8 and 2 mm and which is filled with a non-conductive open structure, is made between each electrode and the surface of the collector-exchanger, with the aid of studs placed on the outer faces of the two parts which constitute the main structure.  
     
     
         24 . Bipolar collector-heat exchanger according to  claim 23 , wherein the non-conductive open structure is a polymer foam whose surface preferably has a hydrophobic nature.  
     
     
         25 . Bipolar collector-heat exchanger according to  claim 23 , wherein the non-conductive open structure is a foam whose core consists of a heat-conducting metallic material and which is coated with an anticorrosion layer having a hydrophobic nature.  
     
     
         26 . Bipolar collector-heat exchanger according to  claim 23 , wherein the non-conductive open structure consists of a polymer mesh which is open longitudinally and whose surface preferably has a hydrophobic nature.  
     
     
         27 . Bipolar collector-heat exchanger according to  claim 18 , wherein the electronically and thermally conductive main structure consists of two parts, at least one of which comprises, further to the studs which are made on one of their faces and are used to define the space between the electrodes and the collector-exchanger, on their other face, cylindrical studs with a height of between 0.5 and 2 mm, having a diameter of between 3 and 10 mm. The two juxtaposed parts create a space intended for circulation of the heat-exchange fluid.  
     
     
         28 . Bipolar collector-heat exchanger according to  claim 27 , wherein the cylindrical studs which are used to make a space intended for circulation of the heat-exchange fluid are distributed uniformly at the surface of the collector-exchanger, in a number such that the total area of their cross section occupies at least 40% of the apparent area of the electrodes.  
     
     
         29 . Bipolar collector-heat exchanger according to  claim 27 , wherein the cylindrical studs which are used to make a space intended for circulation of the heat-exchange fluid are distributed uniformly at the surface of the collector-exchanger, in a number such that the total area of their cross section is less than 10% of the apparent area of the electrodes.  
     
     
         30 . Bipolar collector-heat exchanger according to  claim 29 , wherein the space intended for circulation of the heat-exchange fluid is filled with an open-structured foam consisting of a metallic material which is a good conductor of heat and electricity, the strands of which are in contact with the walls of the main structure.  
     
     
         31 . Bipolar collector-heat exchanger according to  claim 30 , wherein the constituent material of the foam is made of copper or nickel.  
     
     
         32 . Bipolar collector-heat exchanger according to  claim 27 , wherein the walls in contact with the foam are coated with a thin electronically conductive layer such as a metal, a metal alloy or a conductive varnish.  
     
     
         33 . Bipolar collector-heat exchanger according to  claim 30 , wherein the walls in contact with the foam are coated with a thin electronically conductive layer such as a metal, a metal alloy or a conductive varnish.  
     
     
         34 . Bipolar collector-heat exchanger according to  claim 18 , wherein the metal contacts which carry out the discrete collection of the charges and the heat are metal needles which penetrate partially into the main structure, their end being located between 0.4 and 0.9 mm from the plane separating the two parts constituting the main structure.  
     
     
         35 . Bipolar collector-heat exchanger according to  claim 27 , wherein the metal contacts which carry out the discrete collection of the charges and the heat are metal needles which penetrate partially into the main structure, their end being located between 0.4 and 0.9 mm from the plane separating the two parts constituting the main structure.  
     
     
         36 . Bipolar collector-heat exchanger according to  claim 29 , wherein the needles penetrate into the electrodes by a depth of between 0.1 and 0.2 mm, and they are distributed uniformly in square, rectangular or equilateral-triangular patterns.