Abstract: A fuel cell assembly having manifold means for providing fuel and air to, and removing spent fuel and air from, flow passageways across the anodes and cathodes in a fuel cell stack. The sizes and proportions of the supply and return manifolds are optimized, and the total cross-sectional area of the return manifold is about twice the cross-sectional area of the supply manifold. The pressure drop in the manifolds is less than about one-quarter of the total pressure drop across the anode and cathode passageways in the stack, which ratio may be attained by adjusting the thickness of the anode and cathode spacers and/or the size of the chimneys. Widthwise uniformity of flow across the anodes and cathodes is improved by forming each of the manifolds as a plurality of smaller, parallel flow conduits.

Abstract: In a fuel cell assembly, nickel-based anodes are readily oxidized when exposed to oxygen as may happen through atmospheric invasion of the assembly during cool-down following shutdown of the assembly. Repeated anode oxidation and reduction can be destructive of the anodes, leading to cracking and failure. To prevent such oxygen migration, check valves and oxygen getter devices containing oxygen-scavenging material such as metallic nickel are provided in the reformate passageways leading to and from the anodes. The check valves preferably are closed by gravity. Oxidation of the oxygen-gettering material is readily reversed through reduction by reformate when the assembly is restarted.

Abstract: A solid-oxide fuel cell system having a compact, highly space-efficient basal manifold for conveying high temperature air, exhaust, and hydrogen-rich reformate fuel to and from the core components of the system. The manifold is a three-dimensional assembly of plates and partitioned elements which are easily and inexpensively formed. When assembled, the manifold comprises a network of passageways which allow for the mounting, close-coupling, and integration of critical fuel cell system components, including heat exchangers, a tail gas combustor and fuel reformer, solid-oxide fuel cell stacks, check valves, and oxygen scavengers.

Abstract: In a solid-oxide fuel cell assembly, at least one positive displacement air supply (PDAS) pump supplies at least a portion of the air required for various functional air streams through the assembly. Mass air flow through each PDAS pump is readily controlled to a predetermined flow by controlling the rotational speed of the pump, obviating the need for an MAF sensor and control valve. Preferably, each different air stream through the assembly is controlled by its own PDAS pump, sized for the required flow, allowing each to operate at its optimal pressure and thereby minimizing the parasitic electrical cost of providing air to the SOFC assembly.

Abstract: A fuel cell assembly or system including flexible metal bellows elements in one or more tubes intended for carrying hot gases during operation of the assembly. The bellows elements include a tubing element having plurality of annular corrugated folds. Thermal expansion and contraction of rigid tubes and of the non-tubular elements of the assembly can lead to buckling, cracking, and failure of the tubes and failure of the assembly or system. The flexible bellows elements, having relatively low axial and radial spring rates thus are able to absorb thermal and vibrational dimensional changes in the assembly. In addition, the corrugations provide significant resistance to axial heat flow and large radiant surface area, thus increasing thermal isolation where desired between relatively hot and relatively cold regions of the assembly.

Abstract: In a fuel cell assembly, nickel-based anodes are readily oxidized when exposed to oxygen as may happen through atmospheric invasion of the assembly during cool-down following shutdown of the assembly. Repeated anode oxidation and reduction can be destructive of the anodes, leading to cracking and failure. To prevent such oxygen migration, oxygen getter devices containing oxygen-gettering material such as metallic nickel are provided in the fuel passageways leading to and from the anodes. Oxidation of the oxygen-gettering material is readily reversed through reduction by fuel when the assembly is restarted.

Abstract: A solid-oxide fuel cell system having “hot” components, e.g., the fuel cell stacks, the fuel reformer, tail gas combuster, heat exchangers, and fuel/air manifold, contained in a “hot zone” within a thermal enclosure intended specifically for minimizing heat transfer to its exterior and having no significant structural or protective function for its contents. A two-part clamshell arrangement allows all piping and leads which must pass through the enclosure to do so at the join line between the parts, thus eliminating need for ports and fittings in the thermal enclosure. A separate and larger structural enclosure surrounds the thermal enclosure, defining a “cool zone” outside the thermal enclosure for incorporation of “cool” components, e.g., the air supply system and the electronic control system, and providing structural protection for all components of the fuel cell system.

Abstract: A load frame with mechanical springs for providing compression to a fuel cell stack during assembly and operation of a fuel cell assembly. The stack assembly load frame includes a base plate for supporting the stack, a moveable spring holder above the stack, a retaining plate above the spring holder, and tubular supports or rods retaining the post-sintered spacing established by the applied load defining the spacing of the base plate from the retaining plate. A spring for maintaining compression in each stack is positioned between the spring holder and the retaining plate. The invention further comprises a method for assembling a fuel cell assembly to provide an adequate compressive load to the stack during assembly and operation.

Abstract: In a solid-oxide fuel cell system, an integrated air supply system provides oxygen for the fuel cell cathode reaction via a first air flow through a heat exchanger and a second air flow bypassing the heat exchanger, at least one of the first and second flows being throttled by a control valve responsive to a fuel cell control system, the flows subsequently being combined to provide air to the cathodes at a desired temperature.

Abstract: An improved system for more uniformly distributing gaseous fuel over the anode surface of a fuel cell, comprising an interconnect subassembly for electrically connecting anodes and cathodes of adjacent fuel cells in a fuel cell stack. The subassembly includes a perforated plate disposed adjacent the anode surface. The plate may be parallel to or inclined to the anode surface and forms a first wall of a fuel plenum for uniformly distributing fuel via the perforations over the entire surface of the anode. The second wall of the plenum is a plate separating the fuel flow from air flowing across the cathode. Electrical continuity across the interconnect subassembly may be provided, for example, by non-planar upsets such as bumps and dimples in the two plenum plate components, or by metallic foam or filaments disposed between the plates and the electrodes.

Abstract: A solid-oxide fuel cell system having an integrated air supply system, including a central air pump, distribution manifold, air control valves, mass air flow sensors, and supply ducts, for controllably supplying oxygen for the fuel cell reaction, both through and controllably bypassing cathode air heat exchangers; combustion air for a combustor of tail gas from the anodes; cooling air for electronic controls; and reforming air to a liquid fuel vaporizer integral with a hydrocarbon fuel reformer.

Abstract: Interconnects and perimeter spacers for a fuel cell stack are provided as flexible elements which can conform to non-planarities in a stack's electrolyte elements and thereby avoid inducing torsional stresses in the electrolyte elements. The interconnects are foil elements about 0.005 inches thick, formed of a superalloy such as Hastelloy, Haynes 230, or a stainless steel. The perimeter spacers comprise a plurality of laminate thin spacer elements, each thin spacer element being a laminate of superalloy and a “soft” material such as copper, nickel, or mica. The spacer elements can slide past one another; thus the perimeter spacers can be physically thick, to form the gas flow spaces within the stack, while also being torsionally flexible.

Abstract: An interconnect element for electrically connecting an anode and a cathode in adjacent fuel cells in a fuel cell stack, wherein said interconnect element has at least one featured surface including dimples, bosses, and/or pins arranged in a two-dimensional pattern. Preferably, both surfaces are featured, as by mechanical dimpling, embossing, or chemical etching, so that protrusions of the interconnect surface extend into either or both of the adjacent gas flow spaces to make electrical contact with the surfaces of the anode and cathode. This permits conduction of heat from the anode. The protrusions create turbulence in gas flowing through the flow spaces, which increases hydrogen consumption at the anode and hence electric output of the cell.

Abstract: There is disclosed a method of coloring cigarette paper. Cigarette paper is made by forming a furnish, adding at least one colorant to the furnish, forming a sheet of paper from the thus treated furnish, and adding at least one colorant to the paper to produce a variety of tans/browns and red-brown cigarette wrapper.