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 glass ceramic composition for sealing adjacent metal cassettes in an SOFC stack. The seal composition comprises an alumina-silicate glass ceramic matrix and a ceramic fiber aggregate dispersed in the matrix. Preferably, the fiber is selected from the group consisting of zirconium oxide fiber, alumina fiber, and combinations thereof. Preferably, the fiber is present at 1-60 weight percent with respect to the weight of glass ceramic, preferably about 30 weight percent. Preferably, the zirconia is stabilized by up to about 10% yttria. Alumina fiber may substitute for a portion of the zirconia fiber. Preferably, a green seal is die cut from a green tape sheet formed by extrusion of a slurry comprising water and a latex binder. The green seal is sintered during the final SOFC stack assembly process to form the final stack seal.
Abstract:
A method of preventing anode oxidation in a fuel cell (10) is disclosed comprising applying a negative current to an anode (30) of said fuel cell (10), such that the anode (30) is disposed in ionic communication with a cathode (50) through an electrolyte (40). Oxygen is transferred from the anode (30) through the electrolyte (40) to the cathode (50). A method preventing anode oxidation in a fuel cell (10) by storing and using a reformate and doping an anode (30) are also disclosed.
Abstract:
An electrically-conductive mesh spacer (42) incorporated into the hydrogen and air gas flow spaces (22,24) between each anode (14) and cathode (16) and its adjacent interconnect (40) in a fuel cell stack (76). 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 (14,16) and the interconnect element (40). The formed mesh spacer (42) 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 (76). The height (48') 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 (48") during assembly of a fuel cell stack. Because the metal mesh is both compliant and resilient, the compressed spacer (48") is continuously urged into mechanical and electrical contact with its electrode (14,16) over all temperatures and pressures to which the fuel cell assembly may be subjected during use.
Abstract:
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.
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:
A method of preventing anode oxidation in a fuel cell (10) is disclosed comprising applying a negative current to an anode (30) of said fuel cell (10), such that the anode (30) is disposed in ionic communication with a cathode (50) through an electrolyte (40). Oxygen is transferred from the anode (30) through the electrolyte (40) to the cathode (50). A method preventing anode oxidation in a fuel cell (10) by storing and using a reformate and doping an anode (30) are also disclosed.
Abstract:
A reformate gas generating device for an energy conversion device comprises a trapping system (110) comprising a filter element (124) and a trap element (140), and a reforming system (100). The reforming system (100) is coupled to the trapping system (110), which is positioned after said reforming system (100). The trapping system (110) is monitored by a combination of devices including an on-board diagnostic system, a temperature sensor (116), and a pressure differential sensor (118), which can individually or in combination determine when to regenerate the trapping system (110). The method for trapping sulfur and particulate matter using the trapping system (110) comprises dispensing fuel into the energy conversion device. The fuel is processed in a reformer system (100) to produce a reformate. The reformate is introduced into the trapping system (110) and filtered to remove particulate matter and sulfur.