Current density distributor for use in an electrode

Abstract

A mesh-shaped, porous electric current density distributor is for use with an electrode, and is adapted for providing electric current to an active layer of the electrode. The active layer contacts a face of the current density distributor, and the current density distributor includes a porous mesh having several electrically conductive paths. At least part of the electrically conductive paths extend along a direction of major current flow over the current density distributor. The porous mesh includes in a direction crosswise to the direction of major electric current flow, several paths of an electric insulator. The current carrying capacity of the current density distributor in crosswise direction to the major current flow over the current density distributor is smaller than the current carrying capacity in the direction along the major current flow over the current density distributor.

What is claimed is: 
     
         1 . A current density distributor comprising:
 an electrically conductive frame and a porous mesh mounted into the electrically conductive frame,   wherein the electrically conductive frame comprises a lug adapted for providing electric current to the current density distributor, wherein the electric current flows along a direction of major current flow along the current density distributor,   wherein the current density distributor comprises a porous mesh having a plurality of electrically conductive paths,   wherein at least part of the electrically conductive paths extend along the direction of major current flow over the current density distributor,   wherein the porous mesh comprises, in a direction crosswise to the direction of major current flow, a plurality of first electrically insulating paths, and   wherein the porous mesh comprises a plurality of open spaces between the electrically conductive paths and/or the first electrically insulating paths.   
     
     
         2 . The current density distributor as claimed in  claim 1 , wherein a current carrying capacity of the current density distributor in the direction crosswise to the direction of major current flow over the current density distributor is smaller than a current carrying capacity in the direction along the direction of major current flow over the current density distributor, 
     
     
         3 . The current density distributor as claimed in  claim 1 , wherein the porous mesh comprises in crosswise direction to the direction of major current flow a number of electrically conductive paths, wherein the number of electrically conductive paths in the direction crosswise to the direction of major current flow per length unit is smaller than the number of electrically conductive paths per length unit along the direction of major current flow. 
     
     
         4 . The current density distributor as claimed in  claim 1 , wherein the electrically conductive paths comprise along the direction parallel to the current flow a plurality of first electrically conductive paths, and a plurality of second electrically conductive paths, wherein the first electrically conductive paths have a cross section which is larger in comparison to a cross section of the second electrically conductive paths. 
     
     
         5 . The current density distributor according to  claim 1 , wherein the porous mesh comprises along the direction of major current flow over the current density distributor, a plurality of electrically insulating paths. 
     
     
         6 . The current density distributor according to  claim 5 , wherein along the direction of major current flow the electrically conductive paths and the electrically insulating paths are alternatingly provided. 
     
     
         7 . The current density distributor according to  claim 1 , further comprising a plurality of second electrically insulating paths, wherein the electrically conductive paths and the first and second electrically insulating paths are arranged according to a regular geometric pattern. 
     
     
         8 . The current density distributor according to  claim 1 , wherein the electrically conductive paths comprise a plurality of electrically conductive wires, and wherein the first paths of an electric insulator comprise a plurality of threads of an electric insulator. 
     
     
         9 . The current density distributor according to  claim 1 , wherein electrical conductivity of the electrically conductive paths at 20° C. is preferably at least 1.25×10E3 S/m. 
     
     
         10 . The current density distributor according to  claim 1 , wherein the resistivity of the electrically conductive paths is less than 8×10E(−4) Ohm·m. 
     
     
         11 . The current density distributor according to  claim 1 , wherein a material of which the electrically conductive paths are produced offers a tensile strength of at least 120 MPa. 
     
     
         12 . The current density distributor according to  claim 1 , wherein a material for the electrically insulating paths has an electrical resistance at 20° C. of at least 10E12 Ohm·m. 
     
     
         13 . The current density distributor according to  claim 1 , wherein a material for the electrically insulating paths has a tensile strength of at least 15 MPa. 
     
     
         14 . The current density distributor according to  claim 1 , wherein a material for the electric insulator is selected from the group consisting of polyaramides, polyesters, polyolefins, polyetherketone, polyphenylene sulfide, polyether imide (PEI), aliphatic polyamides, fluoroplastics, and a composite material comprising a polymeric matrix of one or more of the polymers indicated above, or any combination or blend of two or more of the afore-mentioned polymers indicated above and wherein the material for the electric insulator further comprises a reinforcing component comprising glass fiber and/or ceramic fiber. 
     
     
         15 . The current density distributor according to  claim 14 , wherein a material for the electric insulator is polyethylene terephthalate, UHMWPE, HDPE, polypropylene, PTFE, ETFE, FEP, PFA, EFEP, or PCTFE. 
     
     
         16 . The current density distributor according to  claim 1 , wherein a material of which the electrically conductive paths are produced is selected from the group consisting of conductive polymers, metal alloys comprising one or more metals selected from the group consisting of gold, iridium, platinum, rhodium, palladium, silver, copper, nickel, zinc, tungsten, titanium, aluminum, tin, steel, stainless steel alloys, austenitic stainless steels, and duplex stainless steel. 
     
     
         17 . The current density distributor according to  claim 1 , wherein the porous mesh comprises a material selected from the group consisting of a woven wire, a knitted wire, a braided wire, a welded wire, an expanded mesh, a plate having a plurality of holes, a screen having a plurality of holes, and a plate having a plurality of holes, which has been photo-chemically etched or electroformed to provide the electrically conductive paths. 
     
     
         18 . The current density distributor according to  claim 1 , wherein the porous mesh has an open area of at least 50%, wherein the open area represents the ratio of the area occupied by the open spaces between the electrically conductive paths and/or the electrically insulating paths. 
     
     
         19 . The current density distributor according to  claim 1 , wherein the electrically conductive paths have an average cross section of 50 μm to 500 μm. 
     
     
         20 . The current density distributor according to  claim 1 , wherein the number of electrically conductive paths in the porous mesh is between 10 and 50 paths per cm. 
     
     
         21 . The current density distributor according to  claim 1 , wherein the number of electrically insulating paths in the porous mesh is between 10 and 50 paths per cm.