A fuel cell stack is formed by stacking a plurality of fuel cells in a stacking direction. Each fuel cell is formed by stacking a membrane electrode assembly and a separator together. The membrane electrode assembly includes a pair of electrodes and an electrolyte membrane interposed between the electrodes, end plates provided at both ends, a fluid passage extending in the stacking direction for allowing one of reactant gases and a coolant to flow through the fluid passage, a connection pipe connecting the fluid passage and an external pipe. The connection pipe has one fluid inlet, two intermediate pipe portions branched from the one fluid inlet, and two fluid outlets. A total intermediate opening cross sectional area is larger than an inlet opening cross sectional area of the one fluid inlet, and the total intermediate opening cross sectional area is larger than a total outlet opening cross sectional area.

A separator plate for an electrochemical system has two metal individual plates. The plates have passage openings for operating media and possibly coolant, and distribution structures. The distribution structures are formed in the metal individual plates and which each communicate with at least two of the passage openings. A peripherally extending sealing structure is formed in each of the metal individual plates at least peripherally around the electrochemically active region and at a distance therefrom and/or peripherally around at least one of the passage openings and at a distance from the edge thereof. The cross-section of the sealing structure has a bead roof, two bead flanks, and at least in some segments, two bead feet. At least in the region of the bead roof of the sealing structure at least in some segments, the sealing structure extends sinuously with at least two wave periods having convex and concave segments.

A fuel cell stack in which cell units are stacked one on top of another, each of the cell units including: a power generation cell; and a separator defining and forming a flow passage portion, being a flow path of the gas, between the separator and the power generation cell, includes a frame body having an insulating property and arranged between at least one set of the cell units adjacent to each other. The frame body includes: as viewed in a stacking direction, outer peripheral beam portions provided to surround an outer peripheral side of a region in which the power generation cell is arranged; a connection beam portion connecting the outer peripheral beam portions to each other; and sealing beam portions formed along sealing portions at least partially sealing a manifold portion through which the gas is allowed to flow to the separator.

A spring compression assembly is configured to apply a load to a stack of electrochemical cells. The assembly includes a ceramic leaf spring, a tensioner configured to apply pressure to a first side of the spring and a bottom plate located on a second side of the spring opposite the first side of the spring. The bottom plate is configured to transfer a load from the spring to the stack of electrochemical cells.

A solid oxide fuel cell includes a solid electrolyte layer, a fuel electrode layer that is disposed on one surface of the solid electrolyte layer, an oxygen electrode layer that is disposed on the other surface of the solid electrolyte layer, and an intermediate layer that is disposed between the solid electrolyte layer and the oxygen electrode layer and that includes ceria-based particles containing rare earth elements other than cerium and ceramic particles consisting of oxide of a metallic element different from that of the ceria-based particles. The ceramic particles having a smaller average particle diameter than that of the ceria-based particles exist in grain boundaries of the ceria-based particles of the intermediate layer.

A fuel-cell single cell has a membrane electrode assembly sandwiched between a pair of separators, and a sealing member that seals a gas channel formed between the membrane electrode assembly and the separators. An uneven portion is formed in a part of the membrane electrode assembly where the sealing member is disposed. A sealing member sump to trap the sealing member is provided at a side exposed to reactant gas pressure and a holder part for the sealing member are provided within a part of the separators where the sealing member is disposed. The uneven portion is opposed to the holder part.

A stack for an electrical energy accumulator is provided having at least one storage cell, which in turn has a storage electrode and an air electrode that is connected to an air supply device, the air supply device having an air distribution plate, wherein the stack also has a water vapor supply device which is in contact with the storage electrode and the air distribution plate has at least one element of the water vapor supply device.

A stack for an electrical energy accumulator is provided having at least one storage cell, which in turn has a storage electrode and an air electrode that is connected to an air supply device, the air supply device having an air distribution plate, wherein the stack also has a water vapor supply device which is in contact with the storage electrode and the air distribution plate has at least one element of the water vapor supply device.

An elastomeric cell frame for a fuel cell includes an insert in which a membrane electrode assembly and a pair of gas diffusion layers disposed on both surfaces of the insert have been bonded; a separator assembly disposed on one of the surfaces of the insert while a pair of separators is configured to face each other; and a sheet-shaped elastomeric frame disposed to surround a rim of the insert and a rim of the separator assembly and a side surface thereof in outside regions of the insert and the separator assembly, and integrally bonded with the rim of the insert and the rim of the separator assembly by thermal bonding.

An elastomeric cell frame for a fuel cell includes an insert in which a membrane electrode assembly and a pair of gas diffusion layers disposed on both surfaces of the insert have been bonded; a separator assembly disposed on one of the surfaces of the insert while a pair of separators is configured to face each other; and a sheet-shaped elastomeric frame disposed to surround a rim of the insert and a rim of the separator assembly and a side surface thereof in outside regions of the insert and the separator assembly, and integrally bonded with the rim of the insert and the rim of the separator assembly by thermal bonding.