Method of making a fuel cell device

Abstract

A fuel cell device is prepared by dispensing and drying electrode and ceramic pastes around two pluralities of removable physical structures to form electrode layers having constant width and a shape that conforms lengthwise to a curvature of the physical structures. An electrolyte ceramic layer is positioned between electrode layers, forming an active cell portion where anode is in opposing relation to cathode with electrolyte therebetween, and passive cell portions where ceramic is adjacent the active cell portion. The layers are laminated, the physical structures pulled out, and the lamination sintered to form an active cell with active passages in anodes and cathodes and passive support structure with passive passages in ceramic. End portions of at least one of the two pluralities of physical structures are curved away from the same end portion of the other of the two pluralities resulting in a split end in the fuel cell device.

What is claimed is: 
     
         1 . A method of making a monolithic fuel cell device, comprising:
 dispensing a paste of anode material around a first plurality of spaced-apart removable physical structures such that the paste flows at least partially around each of the first plurality of spaced-apart removable physical structures;   drying the paste with the first plurality of spaced-apart removable physical structures embedded therein to form an anode layer;   dispensing a paste of cathode material around a second plurality of spaced-apart removable physical structures such that the paste flows at least partially around each of the second plurality of spaced-apart removable physical structures;   drying the paste with the second plurality of spaced-apart removable physical structures embedded therein to form a cathode layer;   positioning an electrolyte layer between the cathode layer and the anode layer to form a stack,   removing the first and second plurality of removable physical structures from the stack to form spaced-apart passages in each of the anode layer and the cathode layer; and   sintering the stack,   wherein an active cell of the stack is formed by the anode layer in opposing relation to the cathode layer with the electrolyte layer therebetween with spaced-apart passages defined in sintered anode material and sintered cathode material.   
     
     
         2 . The method of  claim 1 , further comprising
 dispensing a paste of ceramic material around the first and second plurality of spaced-apart removable physical structures adjacent to the anode materials while in the mold and the cathode materials while in the mold to at least partially surround each of the first and second plurality of spaced-apart removable physical structures with the ceramic material,   wherein during drying, the ceramic paste forms a passive support adjacent each of the anode material and the cathode material, and   wherein sintering forms a passive support structure having passages formed therein that transitions integrally to the spaced-apart passages within the active cell.   
     
     
         3 . The method of  claim 1  wherein dispensing one or both of the pastes includes dispensing a layer of paste into the mold and wherein the method further includes placing the first and/or second plurality of spaced-apart removable physical structures on the layer of paste and then further dispensing the paste over the first and/or second plurality of spaced-apart removable physical structures. 
     
     
         4 . The method of  claim 1  wherein dispensing the pastes further includes dispensing at least two different material sub-layers to form a first sub-layer of porous anode material or a first sub-layer of porous cathode paste material and a second sub-layer of non-porous anode material or a second sub-layer of non-porous cathode paste material dispensed over the first sub-layer. 
     
     
         5 . The method of  claim 4  wherein the first sub-layer is dispensed around the respective first or second plurality of spaced-apart removable physical structures such that, after sintering, the spaced-apart passages are embedded in and supported by the sintered porous anode or the sintered porous cathode. 
     
     
         6 . The method of  claim 4  wherein the first sub-layer is dispensed around one side of the respective first or second plurality of spaced-apart removable physical structures and the second sub-layer is dispensed around the opposing side of the respective first or second plurality of spaced-apart removable physical structures such that, after sintering, the spaced-apart passages are supported by the sintered porous anode or the sintered porous cathode on one side and supported by the sintered non-porous anode or the sintered non-porous cathode on the opposing side. 
     
     
         7 . The method of  claim 4  wherein the at least two different material sub-layers include a plurality of sub-layers each with a differing porosity, with the anode layer and/or the cathode layer decreasing in porosity in a thickness direction away from the electrolyte layer. 
     
     
         8 . The method of  claim 1  wherein dispensing the pastes to form one or both of the anode layer and cathode layer includes dispensing the paste with a varying composition in the thickness direction of the removable physical structures, wherein the variation in composition is selected from amount of porosity, size of pores, chemical composition, relative electrical conductivity, relative ionic conductivity, bonding properties, ratio of anode or cathode material to ceramic material, or a combination thereof. 
     
     
         9 . The method of  claim 8  wherein the varying composition includes a graded porosity with the porosity decreasing in a thickness direction away from the electrolyte layer. 
     
     
         10 . The method of  claim 1  wherein dispensing the paste includes dispensing the paste of the anode material and dispensing the paste of the cathode material with a varying composition in the length direction of the removable physical structures. 
     
     
         11 . The method of  claim 10  wherein the varying composition includes alternating dispensing of the paste of the anode material or the paste of the cathode material according to a predetermined length portions with dispensing of a paste of a ceramic material. 
     
     
         12 . The method of  claim 1  wherein in the stack an active cell portion is formed by the anode layer in opposing relation to the cathode layer, the method further comprising:
 placing a ceramic support layer over the active cell portion and providing an exposed conductive portion extending through the ceramic support layer; and 
 repeating dispensing the paste of the anode material and the paste of the cathode material and positioning the electrolyte layer therebetween to form additional active cell portions with the anode layer of one active cell portion adjacent the cathode layer of the next vertically adjacent active cell portion, with the ceramic support layer between the vertically adjacent active cell portions with the exposed conductive portion electrically connecting the active cell portions in series. 
 
     
     
         13 . The method of  claim 12  wherein the ceramic support layer is a green sheet of non-conductive ceramic material with spaced apart holes that are filled with conductive paste to form the exposed conductive portion and during placing the ceramic support layer, the green sheet is positioned on the active cell portion. 
     
     
         14 . The method of  claim 12  wherein the exposed conductive portions are formed by providing two ceramic support layers having spaced via holes formed therein and coating one side of each of the two ceramic support layers with a conductive material and placing the coated sides in contact with each other with the via holes of one ceramic support layer offset from the via holes of the other ceramic support layer. 
     
     
         15 . The method of  claim 1  wherein the removable physical structures change shape along the length of thereof. 
     
     
         16 . The method of  claim 1  wherein removing the first and second plurality of removable physical structures includes heating the respective layer. 
     
     
         17 . The method of  claim 1  wherein dispensing the paste of the anode material and/or the dispensing of the paste of the cathode material includes dispensing the paste in a mold. 
     
     
         18 . The method of  claim 1  wherein dispensing the paste of the anode material or dispensing the paste of the cathode material includes dispensing the paste onto the electrolyte layer.