A side-channel compressor (1) for a fuel cell system (37) for conveying and/or compressing a gas, in particular hydrogen, having a housing (3), having a compressor chamber (30) which is situated in the housing (3) and which has two encircling side channels (19, 21), having a compressor impeller (2) which is situated in the housing (3) and which is arranged so as to be rotatable about an axis of rotation (4), wherein the compressor impeller (2) has conveying cells (28) arranged at the circumference thereof and in the region of the compressor chamber (30), and having in each case one gas inlet opening (14) formed on the housing (3) and one gas outlet opening (16), which openings are fluidically connected to one another via the compressor chamber (30), in particular the two side channels (19, 21), and wherein, in the region of the compressor chamber (30), an encapsulation of the respective side channel (19, 21) is realized by at least one separation region (35) by means of a surface pairing of the compressor wheel (2) and of the housing (3). According to the invention, here, the at least one separation region (35) is formed by a surface pairing of the components compressor impeller (2) and housing (3) such that the respective one component has encircling edges (5), in particular with encircling tips (11), and the respective other component has an encircling, at least approximately planar counterpart surface (23).

A fuel cell stack includes single cells stacked in a first direction. Each single cell includes a power generating unit, a first separator, and a second separator. The first separator and the second separator hold the power generating unit between the first separator and the second separator. The first separator of each single cell includes first protrusions. The second separator of each single cell includes second protrusions. A distal end of each second protrusion includes a depression that is located at a center in a second direction and extends in a third direction. A length of the depression in the second direction is greater than a length of the first protrusion in the second direction. A distal end of each first protrusion is located inside the depression.

A fuel cell stack includes single cells stacked in a first direction. Each single cell includes a power generating unit, a first separator, and a second separator. The first separator and the second separator hold the power generating unit between the first separator and the second separator. The first separator of each single cell includes first protrusions. The second separator of each single cell includes second protrusions. A distal end of each second protrusion includes a depression that is located at a center in a second direction and extends in a third direction. A length of the depression in the second direction is greater than a length of the first protrusion in the second direction. A distal end of each first protrusion is located inside the depression.

A bipolar plate formed with a reactant flow field on each of its plate surfaces facing away from each other, comprises multiple flow ducts for a reaction medium, bounded by walls of webs, wherein the respective reactant flow field is connected fluidically to a media port across a distribution region situated outside an active region, wherein at least one duct of the distribution field is provided with a flow divider to divide up a flowing reaction medium before it is introduced into the active region. The duct comprising the flow divider has a duct elevation, comprising an ascent, which is present at a given distance upstream from the flow divider. A fuel cell stack having a plurality of such bipolar plates is also provided.

A bipolar plate formed with a reactant flow field on each of its plate surfaces facing away from each other, comprises multiple flow ducts for a reaction medium, bounded by walls of webs, wherein the respective reactant flow field is connected fluidically to a media port across a distribution region situated outside an active region, wherein at least one duct of the distribution field is provided with a flow divider to divide up a flowing reaction medium before it is introduced into the active region. The duct comprising the flow divider has a duct elevation, comprising an ascent, which is present at a given distance upstream from the flow divider. A fuel cell stack having a plurality of such bipolar plates is also provided.

Provided is a fuel cell having excellent gas diffusivity and leading to suppressed pressure drop even with a porous body as a gas path. The fuel cell includes: plural stacked power generating unit cells each having a membrane assembly, an anode separator stacked on the membrane assembly on one side, and a cathode separator stacked on the membrane assembly on the other side, wherein the anode separator of any one of the power generating unit cells is stacked on the cathode separator of another one thereof that is adjacent to said any one, the cathode separator has a porous body where an oxidizing gas flows, and a path enlarging member, and the path enlarging member includes gas path enlarging portions that enlarge a path formed by the porous body, the gas path enlarging portions having wall parts inclining or orthogonal to a direction where the oxidizing gas flows.

Provided is a fuel cell having excellent gas diffusivity and leading to suppressed pressure drop even with a porous body as a gas path. The fuel cell includes: plural stacked power generating unit cells each having a membrane assembly, an anode separator stacked on the membrane assembly on one side, and a cathode separator stacked on the membrane assembly on the other side, wherein the anode separator of any one of the power generating unit cells is stacked on the cathode separator of another one thereof that is adjacent to said any one, the cathode separator has a porous body where an oxidizing gas flows, and a path enlarging member, and the path enlarging member includes gas path enlarging portions that enlarge a path formed by the porous body, the gas path enlarging portions having wall parts inclining or orthogonal to a direction where the oxidizing gas flows.

A fuel cell separator which is obtained by molding a composition that contains a carbonaceous material and a resin, and which is provided with a sealing part and a groove that serves as a gas flow channel on one surface or both surfaces. This fuel cell separator is configured such that the arithmetic mean heights Sa of the surface of the sealing part and the bottom surface and the peak of the groove on at least one surface are 0.50-1.60 μm and the profile peak heights Spk thereof are 1.50 μm or less as determined in accordance with ISO 25178-2 (2012). Consequently, this fuel cell separator has good hydrophilicity and good adhesion to a gasket.

A fuel cell separator which is obtained by molding a composition that contains a carbonaceous material and a resin, and which is provided with a sealing part and a groove that serves as a gas flow channel on one surface or both surfaces. This fuel cell separator is configured such that the arithmetic mean heights Sa of the surface of the sealing part and the bottom surface and the peak of the groove on at least one surface are 0.50-1.60 μm and the profile peak heights Spk thereof are 1.50 μm or less as determined in accordance with ISO 25178-2 (2012). Consequently, this fuel cell separator has good hydrophilicity and good adhesion to a gasket.

An improved or advanced electrically conductive selectively gas permeable anode flow field (SGPFF) design, allowing for efficient removal of CO.sub.2 perpendicular to the active area near the location where it is formed in the catalyst layer. The anode plate design includes two mating flow fields (an anode gaseous flow field, and an anode liquid flow field) separated by a semi-permeable separator. The separator comprises a hydrophobic semi-permeable separator for CO.sub.2 diffusive gas transport from the liquid side (with acid, water, and CO.sub.2) to the gaseous side (allowing for CO.sub.2 removal to the atmosphere).