Solid oxide fuel cell device

Abstract

A fuel cell device with a rectangular solid ceramic substrate extending in length between first and second end surfaces where thermal expansion occurs primarily along the length. An active structure internal to the exterior surface extends along only a first portion of the length and has an anode, cathode and electrolyte therebetween. The first portion is heated to generate a fuel cell reaction. A remaining portion of the length is a non-heated, non-active section lacking opposing anode and cathode where heat dissipates along the remaining portion away from the first portion. A second portion of the length in the remaining portion is distanced away from the first portion such that its exterior surface is at low temperature when the first portion is heated. The anode and cathode have electrical pathways extending from the internal active structure to the exterior surface in the second portion for electrical connection at low temperature.

1 - 14 . (canceled) 
     
     
         15 . A solid oxide fuel cell device comprising:
 a ceramic monolith of rectangular dimensions having a length, width, and thickness with the length being the greatest dimension, the ceramic monolith including:   a fuel passage extending at least in part in the direction of the length dimension and opening to a surface of the ceramic monolith at an inlet and opening to a surface at an outlet;   an oxidizer extending at least in part in the direction of the length dimension and opening to a surface of the ceramic monolith at an inlet and opening to a surface at an outlet;   an electrolyte disposed between the fuel passage and the oxidizer passage;   an anode exposed in the fuel passage with a first portion between the electrolyte and the fuel passage; and   a cathode exposed in the oxidizer passage with a first portion between the electrolyte and the oxidizer passage,   wherein the first portion of the anode and the first portion of the cathode are in opposing relation with the electrolyte therebetween and forming an active region, and each of the anode and the cathode includes a second portion extending in the corresponding passage toward one of the correspondence inlets or outlets, the second portions of the anode and cathode are not in opposing relation.   
     
     
         16 . The fuel cell device of  claim 15  wherein each of the anode and cathode extends to one of the corresponding inlet or outlet. 
     
     
         17 . The fuel cell device of  claim 15  wherein each of the anode and cathode extends to an exterior surface of the ceramic monolith adjacent to one of the corresponding inlet or outlet. 
     
     
         18 . The fuel cell device of  claim 15  further including low temperature rigid electrical connections in electrical communication with respective ones of the second portion of the anode and the second portions of the cathode. 
     
     
         19 . The fuel cell device of  claim 15  further including a contact pad on an exterior surface of ceramic monolith in electrical communication with the anode and a contact pad on an exterior surface of the ceramic monolith in electrical communication with the cathode. 
     
     
         20 . The fuel cell device of  claim 15  wherein the ceramic monolith has dimensions of 0.2 inch thick and 0.5 inch width and the length is at least 5 times greater than the thickness. 
     
     
         21 . The fuel cell device of  claim 15  wherein the ceramic monolith has a first end and a second end and the length between the first end and the second end is substantially greater than the width and the thickness whereby the ceramic monolith exhibits thermal expansion along a dominant axis that is coextensive with the length. 
     
     
         22 . A solid oxide fuel cell system comprising:
 a hot zone chamber;   a plurality of the solid oxide fuel cell devices of claim  1 , each positioned with the active region in the hot zone chamber and the second portion of the anode and the second portion of the cathode extending outside the hot zone chamber;   a heat source coupled to the hot zone chamber and adapted to provide the applied heat to heat the active regions to an operating reaction temperature within the hot zone chamber;   a fuel gas supply coupled outside the hot zone chamber to the fuel inlets for supplying a fuel gas flow into the fuel passages; and   an oxidizer gas supply coupled outside the hot zone chamber to the oxidizer inlets for supplying an oxidizer gas flow into the oxidizer passages.   
     
     
         23 . The fuel cell system of  claim 22  further comprising an insulating region between the heat source and the second portion of the anode and the second portion of the cathode, the insulating region being adapted to maintain the second portions at a temperature below the operating reaction temperature. 
     
     
         24 . The fuel cell system of  claim 23  wherein the operating reaction temperature is greater than 700° C. and the temperature of the second portion where the fuel gas and oxidizer gas supplies are coupled to the fuel and oxidizer inlets is less than 300° C. 
     
     
         25 . A method of using the device of  claim 15 , comprising:
 positioning the ceramic monolith with the active region in a hot zone chamber and the second portions extending outside the hot zone chamber;   coupling a fuel gas supply outside the hot zone chamber to the fuel gas inlet;   coupling an oxidizer supply outside the hot zone chamber to the oxidizer gas inlet;   applying heat in the hot zone chamber to heat the active region to an operating temperature above 700° C. while maintaining the inlets at a low temperature less than 300° C.;   supplying fuel gas and oxidizer gas through the respective fuel and oxidizer inlets to the respective fuel and oxidizer passages in the heated active region whereby the fuel and oxidizer react and produce electrons to produce a voltage between the second portion of the anode and the second portion of the cathode.   
     
     
         26 . A method of using the system of  claim 22 , comprising:
 applying heat in the hot zone chamber to heat the active regions to an operating temperature above 700° C. while maintaining the fuel and oxidizer inlets at a low temperature less than 300° C.;   supplying fuel and air from the respective fuel gas and oxidizer gas supplies into the respective fuel and air passages to the heated active region to react the fuel and oxidizer and produce electrons whereby a voltage develops between the second portion of the anode and the second portion of the cathode.