摘要:
A modular fuel cell cassette for use in assembling a fuel cell stack comprising a metal separator plate and a metal cell-mounting plate joined at their edges to form a hollow cassette. A fuel cell subassembly is attached to the mounting plate and extends through an opening in the mounting plate. The plates include openings to form chimney manifolds for supply and exhaust of fuel gas to the anode and air to the cathode. A conductive interconnect element extends from the fuel cell subassembly to make contact with the next cassette in a stack. The anode openings in the mounting plate and separator plate are separated by spacer rings such that the cassette is incompressible. A fuel cell stack comprises a plurality of cassettes, the mounting plate of one cassette being attached to, and insulated from, the separator plate of the next-adjacent cassette by a dielectric seal surrounding the interconnect.
摘要:
A glass ceramic composition for sealing adjacent metal cassettes in an SOFC stack. The seal composition comprises an alumina-silicate glass ceramic matrix or a matrix of Zr2 and a ceramic fiber aggregate and non-fibrous zirconia 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 fiber is stabilized by up to about 10% yttria. Alumina fiber may substitute for a portion of the zirconia fiber. Preferably, the non-fibrous zirconia is present at about 5 weight percent and is also stabilized.
摘要:
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.
摘要:
In assembling an SOFC fuel cell stack from a plurality of cassettes, the mounting plate of one cassette is attached to, and insulated from, the separator plate of the next-adjacent cassette by a peripheral dielectric seal consisting of a ceramic coating and a metal braze. Materials suitable for the ceramic coating include yttrium stabilized zirconia (YSZ), zirconia toughened alumina, magnesium silicates such as the mineral forsterite, magnesium aluminates, magnesium aluminosilicates and lanthanum zirconate. The ceramic coating may be applied to the cassette's outer surface in known fashion as by physical vapor deposition, chemical vapor deposition, sputtering, and various methods of plasma spray. An underlayer of alumina may also be used to provide a redundant layer of electrical insulation.
摘要:
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.
摘要:
An etched interconnect for fuel cell elements comprising solid oxide electrolyte, an anode, and a cathode, includes a conductive base sheet having first and second faces having anode and cathode gas flow passages, respectively. The anode gas flow passages and cathode gas flow passages each have a unique geometry selected to optimize fuel and oxidant gas flow. In a preferred embodiment, the gas flow passages are prepared using a photochemical etching process.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A solid oxide fuel cell stack that contains a plurality of fuel cells, each of which includes an anode and a cathode disposed on opposite sides of a solid electrolyte, and an electrically conductive interconnect disposed between the anode and cathode. The interconnect includes a substrate and a first surface in electrical contact with the anode and a second surface in electrical contact with the cathode, wherein at least a portion of at least one of the surfaces includes cobalt.