Delphi Technologies, Inc.

Battelle Memorial Institute

Other

Bayerische Motoren Werke Aktiengesellschaft

Subhasish Mukerjee

Karl Jacob Haltiner, Jr

Diane M England

Sean Michael Kelly

Haskell Simpkins

Vincent L Sprenkle

Kerry D Meinhardt

Kenneth Scott Weil

Michael Thomas Faville

Joseph M Keller

Jeffrey G Weissman

Kevin Richard Keegan

Jin Yong Kim

John G Noetzel

Lawrence Andrew Chick

Gary F Reisdorf

M James Grieve

Catherine Vavonese

Dean Paxton

Kaushik Rajashekara

Malcolm James Grieve

Paul E George, Ii

Eric Sidney Mast

Rick Daniel Kerr

Jean Joseph Botti

James Zizelman

Joachim Tachtler

Harry L Husted

John F O'Brien

Donald J Armstrong

David R Schumann

John Charles Weber

John S Hardy

K Scott Weil

Christopher M DeMinco

Amanda M Weiss

Anthony J Derose

James Michael Haller

Lane Wilson

Gregory W Alexander

Juergen T Kammerer

Kurtis P Recknagle

Stefan M Maczynski

Steven R Shaffer

Carolyn D Fleming

Anthony J De Rose

John E Deibler

Larisa S Bobrov

Bernhard Edlinger

Steven L Cooper

Willem Vilders, Iii

Karl Jacob Haltiner Jr

Karl J Haltiner Jr

A method of manufacturing a solid oxide fuel cell stack having an electrically conductive interconnect, including the steps of: (a) providing a first fuel cell and a second fuel cell, (b) providing a substrate having an iron-chromium alloy, (c) depositing a layer of metallic cobalt over a portion of substrate surface, (d) subjecting the layer of metallic cobalt to reducing conditions, (e) then exposing the remaining portion of the layer of metallic cobalt to oxidizing conditions for a predetermined time and temperature, such that the surface portion of the layer of metallic cobalt is oxidized to cobalt oxide, thereby forming the electrically conductive interconnect having a layer of metallic cobalt sandwiched between a surface layer of cobalt oxide and the layer of cobalt-iron-chromium alloy, and (f) sandwiching the substrate between the first and second fuel cells.

Method of manufacturing a fuel cell stack having an electrically conductive interconnect

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.

System for adding sulfur to a fuel cell stack system for improved fuel cell stability

A solid oxide fuel cell stack having a plurality of cassettes and a glass composite seal disposed between the sealing surfaces of adjacent cassettes, thereby joining the cassettes and providing a hermetic seal therebetween. The glass composite seal includes an alkaline earth aluminosilicate (AEAS) glass disposed about a viscous glass such that the AEAS glass retains the viscous glass in a predetermined position between the first and second sealing surfaces. The AEAS glass provides geometric stability to the glass composite seal to maintain the proper distance between the adjacent cassettes while the viscous glass provides for a compliant and self-healing seal. The glass composite seal may include fibers, powders, and/or beads of zirconium oxide, aluminum oxide, yttria-stabilized zirconia (YSZ), or mixtures thereof, to enhance the desirable properties of the glass composite seal.

Solid oxide fuel cell having a glass composite seal

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.

Fuel cell stack having a featured interconnect element

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.

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.

Compliant current collector for fuel cell anode and cathode

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.

Inhibitor for prevention of braze migration in solid oxide fuel cells

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.

Method for improving robustness of solid oxide fuel cell stacks

An electrical interconnect for a solid-oxide fuel cell stack assembly, including a novel sintering paste and an improved manufacturing process for an anode and cathode electrical contacts is disclosed. On the anode side, the paste contains a metallic oxide such as NiO, and an amount of sacrificial pore-forming particles, such as carbon particles or polymer spheres, which are vaporized during sintering of the paste, resulting in a very porous connection having good electrical conductivity and good adhesion. A preferred level of pore-former in the paste is about 40 volume percent. On the cathode side, the paste contains a noble metal such as for example, gold, platinum, palladium or rhodium, and an amount of the sacrificial pore-forming particles. The paste may be applied to the surfaces in a grid pattern or, because the resulting contact is porous after sintering, it may be applied as a continuous layer.

Method and apparatus for forming electrode interconnect contacts for a solid-oxide fuel cell stack

An interconnect system including: a separator plate to provide an anode gas flow space; a first metal interconnect disposed between the separator plate and an anode surface; a nickel oxide paste applied in a pattern over the surface of the anode and adjacent surface of the separator plate which when sintered results in a first conductive layer bonded to the anode and the first interconnect, and a second conductive layer bonded to the first interconnect and the separator plate; a second metal interconnect disposed between a cathode surface of the cell and the separator plate of an adjacent cell cassette; and a silver-containing paste applied over the surface of the cathode and the separator plate which when sintered results in a third conductive layer bonded to the cathode and the second interconnect, and a fourth conductive layer bonded to the second interconnect and the separator plate.

Solid bonded interconnect system in a lightweight solid oxide fuel cell stack

A method for preparing an interconnect is provided. The method comprises: providing a conductive base sheet including a first face and a second face, the first and second faces are disposed on opposite sides of the base sheet; preparing anode gas flow passages on the first face of the conductive base sheet; preparing cathode gas flow passages on the second face of the conductive base sheet; and selecting anode gas flow passage geometry having a first geometric configuration; and selecting cathode gas flow passage geometry having a second geometric configuration that is different from the first geometric configuration so as to optimize fuel and oxidant gas flow according to system requirements.

Method for preparing an interconnect

A solid-oxide fuel cell system wherein a reformate combustor is disposed in the reformate flow path between a hydrocarbon reformer and a fuel cell stack. At system start-up, reformate is partially burned within the combustor by admitting combustion air, and the partially-burned reformate is passed through the anode chambers of the stack to warm the anodes. In addition, reformate is passed through a cathode-air heat exchanger to warm combustion air entering the cathode chambers of the stack. The combustor may continue to be supplied with a low level of air during steady-state operation of the SOFC, thereby providing a moist environment within the anode chambers to prevent coking of the anodes and providing additional heat to the reformate. The combustor decouples the reformer from the stack thermodynamically, permitting the reformer and the stack each to run in its own optimal temperature range.

Solid-oxide fuel cell system having an upstream reformate combustor

An electrical interconnect for a fuel cell assembly comprising a peripheral frame formed of one or more materials having a coefficient of thermal expansion similar to that of adjacent elements to which the interconnect must be bonded and a central portion formed of a corrosion-resistant material for conducting electric current between adjacent fuel cells. Preferably, the central portion is attached to the peripheral frame via a brazed corrugated lap joint for relieving thermal expansion differences between the frame and the central portion. Preferably, the joint includes an interlayer of a ductile material, for example, a nickel, copper, silver or gold layer, which helps to relieve thermal stress between the frame and the central portion.

Hybrid interconnect for a solid-oxide fuel cell stack

In a solid-oxide fuel cell system, a fuel/air manifold conveys air and tail gas fuel from the anodes in a fuel cell stack assembly to a tail gas combustor, producing a heated combustor exhaust having the highest mass flow in the system. The exhaust is passed through a heat exchanger to warm incoming cathode reaction air, and the exhaust is partially cooled by the exchange. From the heat exchanger, the exhaust gas is passed through a tempering jacket space surrounding the fuel cells in the stack. During start-up of the system, the exhaust gas is hotter than the stack and so the warm-up period is shortened. During normal operation of the system, the exhaust gas is cooler than the operating temperature and therefore cooling of the stack is assisted by contact with the exhaust gas.

Solid-oxide fuel cell system having tempering of fuel cell stacks by exhaust gas

A solid-oxide fuel cell system having a relatively large primary fuel cell sub-assembly for steady-state operation and a relatively small secondary fuel cell sub-assembly which is rapidly heatable to a threshold operating temperature to a) produce usable power in a short time period, b) cascade a hot exhaust into the primary fuel cell sub-assembly to assist in preheating thereof, and c) provide steam into the primary fuel cell sub-assembly to prevent coking of the anodes thereof. As the primary sub-assembly reaches its threshold temperature, it too begins to generate electricity and continues to self-heat and to be heated by the secondary sub-assembly. Preferably, the secondary sub-assembly continues to provide electricity in complement with the primary sub-assembly until the primary sub-assembly reaches full power, at which time the secondary sub-assembly may be shut down or switched to standby status for fuel efficiency, as desired.

Cascaded fuel cell stacks for fast start-up and anode coking control

Growing community of inventors

Rochester, NY, United States of America

Subhasish Mukerjee