Abstract: A heater includes a heater housing with a fuel cell stack assembly disposed therein. The fuel cell stack assembly includes a plurality of fuel cells which convert chemical energy from a fuel into heat and electricity through a chemical reaction with an oxidizing agent. The fuel cell stack assembly includes a fuel cell manifold for receiving the fuel within a fuel inlet and the oxidizing agent within an oxidizing agent inlet and distributing the fuel and oxidizing agent to the fuel cells. A fuel supply conduit supplies the fuel to the fuel inlet and an oxidizing agent supply conduit supplies the oxidizing agent to the oxidizing agent inlet. A sonic orifice is disposed between the fuel supply conduit and the fuel inlet or between the oxidizing agent supply conduit and the oxidizing agent inlet, thereby limiting the velocity of the fuel or the oxidizing agent through the sonic orifice.

Abstract: A heater includes a fuel cell stack assembly disposed within a heater housing and includes a plurality of fuel cells which convert chemical energy from a fuel into heat and electricity through a chemical reaction with an oxidizing agent. A combustor disposed within the heater housing receives an anode exhaust and a cathode exhaust from the fuel cell stack assembly and combusts a mixture of the anode exhaust and the cathode exhaust to produce a heated combustor exhaust. The combustor includes a combustor exhaust outlet for discharging the heated combustor exhaust into the heater housing. A baffle disposed around the fuel cell stack assembly and the combustor defines a heat transfer channel radially between the heater housing and the baffle. A flow director in fluid communication with the combustor exhaust outlet and the heat transfer channel communicates the heated combustor exhaust to the heat transfer channel.

Abstract: A heater includes a heater housing with a support plate secured to one end. A fuel cell stack assembly is disposed within the heater housing and includes a plurality of fuel cells which convert chemical energy from a fuel into heat and electricity through a chemical reaction with an oxidizing agent. The fuel cell stack assembly includes a fuel cell manifold for receiving the fuel and distributing the fuel to the plurality of fuel cells and for receiving the oxidizing agent and distributing the oxidizing agent to the plurality of fuel cells. A fuel supply conduit supplies the fuel to the fuel cell manifold and an oxidizing agent supply conduit supplies the oxidizing agent to the fuel cell manifold. The fuel cell stack assembly is supported on the support plate by one of the fuel supply conduit and the oxidizing agent supply conduit.

Abstract: A heater includes a heater housing extending along a heater axis. A fuel cell stack assembly is disposed within the heater housing and includes a plurality of fuel cells which convert chemical energy from a fuel into heat and electricity through a chemical reaction with an oxidizing agent. An electric resistive heating element is disposed within the heater housing. A positive conductor is disposed within the heater housing and is connected to the fuel cell stack assembly and to the electric resistive heating element and a negative conductor is connected to the fuel cell stack assembly and to the electric resistive heating element. The electric resistive heating element is arranged to elevate the fuel cell stack assembly from a first inactive temperature to a second active temperature.

Abstract: A heater includes a heater housing extending along a heater axis. A fuel cell stack assembly is disposed within the heater housing and includes a plurality of fuel cells which convert chemical energy from a fuel into heat and electricity through a chemical reaction with an oxidizing agent. A combustor disposed within the heater housing receives an anode exhaust and a cathode exhaust from the fuel cell stack assembly and combusts a mixture of the anode exhaust and the cathode exhaust to produce a heated combustor exhaust. The combustor includes a combustor exhaust outlet for discharging the heated combustor exhaust into the heater housing. The heater housing is heated by the fuel cell stack assembly and the heated combustor exhaust.

Abstract: A system for adding sulfur to a reformate stream feeding a fuel cell stack, having a sulfur source for providing sulfur to the reformate stream and a metering device in fluid connection with the sulfur source and the reformate stream. The metering device injects sulfur from the sulfur source to the reformate stream at a predetermined rate, thereby providing a conditioned reformate stream to the fuel cell stack. The system provides a conditioned reformate stream having a predetermined sulfur concentration that gives an acceptable balance of minimal drop in initial power with the desired maximum stability of operation over prolonged periods for the fuel cell stack.

Abstract: A fuel cell stack is disclosed including a non-fuel cell cassette having temperature sensing elements disposed therein. The temperature sensing elements are disposed in one or more void spaces in the non-fuel cell cassette, which void spaces are connected to openings in the side of the non-fuel cell cassette for lead wires to communicate information from the temperature sensing elements to components outside of the fuel cell stack.

Abstract: A fuel cell stack is provided with a plurality of fuel cell cassettes where each fuel cell cassette has a fuel cell with an anode and cathode. The fuel cell stack includes an anode supply chimney for supplying fuel to the anode of each fuel cell cassette, an anode return chimney for removing anode exhaust from the anode of each fuel cell cassette, a cathode supply chimney for supplying oxidant to the cathode of each fuel cell cassette, and a cathode return chimney for removing cathode exhaust from the cathode of each fuel cell cassette. A first fuel cell cassette includes a flow control member disposed between the anode supply chimney and the anode return chimney or between the cathode supply chimney and the cathode return chimney such that the flow control member provides a flow restriction different from at least one other fuel cell cassettes.

Abstract: A textured surface is formed on at least one of a fuel cell mounting plate or fuel cell subassembly to define a joint spacing between these two components. In a preferred embodiment, the textured surface comprises a plurality of dimples coined or otherwise formed in the metal mounting plate. The joint spacing improves the manufacturing and assembly process of the fuel cell cassettes through precise application and control of the brazing process which improves the braze joint strength while reducing material cost.

Abstract: A method of making a planar solid oxide fuel cell is described involving: (1) sintering at least an electrolyte layer; (2) juxtaposing one of a sintered anode or cathode layer with a metal substrate, with a bonding agent therebetween; and (3) applying heat to bond the juxtaposed anode or cathode layer to the metal substrate; where the anode and cathode layers are each sintered, together or independently, simultaneously with sintering the electrolyte layer, simultaneously with applying heat to bond the ceramic fuel cell element to the metal substrate, or in one or more separate sintering steps.

Abstract: A system for adding sulfur to a fuel cell stack, having a reformer adapted to reform a hydrocarbon fuel stream containing sulfur contaminants, thereby providing a reformate stream having sulfur; a sulfur trap fluidly coupled downstream of the reformer for removing sulfur from the reformate stream, thereby providing a desulfurized reformate stream; and a metering device in fluid communication with the reformate stream upstream of the sulfur trap and with the desulfurized reformate stream downstream of the sulfur trap. The metering device is adapted to bypass a portion of the reformate stream to mix with the desulfurized reformate stream, thereby producing a conditioned reformate stream having a predetermined sulfur concentration that gives an acceptable balance of minimal drop in initial power with the desired maximum stability of operation over prolonged periods for the fuel cell stack.

Abstract: A fuel cell system is disclosed comprising a plurality of fuel cell modules including a sealed planar fuel cell stack, the stack including internal manifold channels for transport of fuel and air to fuel cells within the stack and transport of tail gas and spent air away from fuel cells within the stack. Each of the fuel cell stacks is mounted on a stack footprint area of a top member of a base manifold. The base manifolds are configured to allow for interconnection of a number of fuel cell stack modules to provide a fuel cell system capable of producing power outputs that otherwise would have required large surface area cells or stack with a large number of cells.

Abstract: A multi-stack fuel cell system is disclosed where multiple fuel cell stacks can be efficiently connected together. The fuel cell system includes a plurality of fuel cell modules include a sealed planar fuel cell stack that has internal manifold channels for transport of fuel and air to fuel cells within the stack and transport of tail gas and spent air away from fuel cells within the stack. Each of the fuel cell stacks is mounted on a base manifold, and the base manifold has side openings in fluid communication with the stack internal manifold channels. The side openings on the base manifold are configured so that the modules can be efficiently connected together.

Abstract: An electrically-conductive mesh spacer incorporated into the hydrogen and air gas flow spaces between each anode and cathode and its adjacent interconnect in a fuel cell stack. The mesh is formed of metal strands and is formed into a predetermined three-dimensional pattern to make contact at a plurality of points on the surfaces of the electrode and the interconnect element. The formed mesh spacer is secured as by brazing to the interconnect element at a plurality of locations to form an interconnect, which preserves the pattern during assembly of a fuel cell stack. The height of the formed pattern is greater than the height of a gas flow space after fuel cell assembly, such that the mesh spacer is slightly compressed during assembly of a fuel cell stack. Because the metal mesh is both compliant and resilient, the compressed spacer is continuously urged into mechanical and electrical contact with its electrode over all temperatures and pressures to which the fuel cell assembly may be subjected during use.

Abstract: A method of operating a fuel cell includes the step of selectively connecting and disconnecting the fuel cell to at least one electrical load dependent at least in part upon at least one of a fuel cell voltage, a fuel cell current and a fuel cell temperature.

Abstract: A method of manufacturing an electrically conductive interconnect for a solid oxide fuel cell stack, including the steps of (a) making a metal substrate having a first surface configured for electrical contact with an anode of the solid oxide fuel cell stack and a second surface configured for electrical contact with a cathode of the solid oxide fuel cell stack; (b) depositing a layer comprising metallic cobalt over at least a portion of at least one of the first and second surfaces; and (c) subjecting the metallic cobalt to reducing conditions, thereby causing at least a portion of the metallic cobalt to diffuse into the metal substrate.

Abstract: A solid oxide fuel cell system comprising a plurality of electrochemically active fuel cell cassettes connected in electrical series and bonded together by a plurality of glass seals to form a fuel cell stack. A dummy cassette containing a thermocouple is disposed within the fuel cell stack. Each cassette may have at least one alignment tab for receiving a rod to maintain stack alignment during sintering, and each fuel cell cassette has electrical terminals extending from a side of the stack for performance testing. The distribution manifold is attached to stack, and a spring subassembly is disposed against the stack and is attached to the manifold by tie rods to maintain a compressive load on the stack through sintering and subsequent use to prevent unloading and rupture of the glass seals.

Abstract: During manufacture of an SOFC assembly, an inhibitor is included to prevent migration of silver braze during subsequent use of the SOFC assembly. The inhibitor may take any of several forms, either individually or in combination. Inhibitors comprehended by the present invention include, but are not limited to: a) a mechanical barrier that can be printed or dispensed onto one or more SOFC stack elements around the braze areas to prevent mechanically-driven migration; b) an electrically insulating feature in the electrolyte or interlayer over the electrolyte layer in the seal margins to prevent electrical potential-driven migration; and 3) chemical modification of the braze itself as by addition of an alloying metal such as palladium.

Abstract: A method for forming a solid oxide fuel cell stack from a plurality of individual solid oxide fuel cells, wherein the anodes of the solid oxide fuel cells are infiltrated by one or more materials for making the anodes less sensitive to sulfur poisoning and/or less subject to carbon degradation and/or for improving the electrochemical performance of the stack, the method comprising the steps of oxidizing the anodes of the individual solid oxide fuel cells before forming a stack, building a solid oxide fuel cell stack with all of the anodes in an oxidized state, reducing all of the anodes, and then infiltrating all of the anodes with at least one of the materials.

Abstract: A fuel cell stack is disclosed including a non-fuel cell cassette having temperature sensing elements disposed therein. The temperature sensing elements are disposed in one or more void spaces in the non-fuel cell cassette, which void spaces are connected to openings in the side of the non-fuel cell cassette for lead wires to communicate information from the temperature sensing elements to components outside of the fuel cell stack.