A bipolar plate formed from two single plates joined together, formed with a reactant flow field on their plate surfaces facing away from each other, comprises multiple flow ducts for a reaction medium, bounded by walls of webs herein the webs and the flow ducts of one of the single plates run opposite the webs and the flow ducts of the other of the single plates in an active region, thus forming coolant ducts of a coolant flow field extending between the single (8), the reactant flow fields and the coolant flow field being each connected fluidically to a media port across a distribution region situated outside the active region, and there being a cross channeling of the two reaction media for a portion in the distribution region. For the channeling of the coolant in the distribution region free of cross currents, at least one of the single plates may be formed with a reduction in height of the webs on its plate surface facing toward the other of the single plates in an intersection region of the reaction media channels, so that two adjacent flow ducts are fluidically connected by the reduction.

A bipolar plate formed from two single plates joined together, formed with a reactant flow field on their plate surfaces facing away from each other, comprises multiple flow ducts for a reaction medium, bounded by walls of webs herein the webs and the flow ducts of one of the single plates run opposite the webs and the flow ducts of the other of the single plates in an active region, thus forming coolant ducts of a coolant flow field extending between the single (8), the reactant flow fields and the coolant flow field being each connected fluidically to a media port across a distribution region situated outside the active region, and there being a cross channeling of the two reaction media for a portion in the distribution region. For the channeling of the coolant in the distribution region free of cross currents, at least one of the single plates may be formed with a reduction in height of the webs on its plate surface facing toward the other of the single plates in an intersection region of the reaction media channels, so that two adjacent flow ducts are fluidically connected by the reduction.

A fuel electrode incorporates a first and second corrugated portion that are attached to each other at offset angles respect to their corrugation axis and therefore reinforce each other. A first corrugated portion may extend orthogonally with respect to a second corrugated portion. The first and second corrugated portions may be formed from metal wire and may therefore have a very high volumetric void fraction and a high surface area to volume ratio (sa/vol). In addition, the strands of the wire may be selected to enable high conductivity to the current collectors while maximizing the sa/vol. In addition, the shape of the corrugation, including the period distance, amplitude and geometry may be selected with respect to the stiffness requirements and electrochemical cell application factors. The first and second corrugated portions may be calendared or crushed to reduce thickness of the fuel electrode.

A fuel electrode incorporates a first and second corrugated portion that are attached to each other at offset angles respect to their corrugation axis and therefore reinforce each other. A first corrugated portion may extend orthogonally with respect to a second corrugated portion. The first and second corrugated portions may be formed from metal wire and may therefore have a very high volumetric void fraction and a high surface area to volume ratio (sa/vol). In addition, the strands of the wire may be selected to enable high conductivity to the current collectors while maximizing the sa/vol. In addition, the shape of the corrugation, including the period distance, amplitude and geometry may be selected with respect to the stiffness requirements and electrochemical cell application factors. The first and second corrugated portions may be calendared or crushed to reduce thickness of the fuel electrode.

A fuel cell stack includes an endplate assembly having a structural endplate. An insulator plate has a second exterior surface contacting a first interior surface of the structural endplate and a second interior surface on an opposite side of the insulator plate. A third plate has a third exterior surface contacting the second interior surface and a third interior surface on an opposite side of the third plate relative to the insulator plate. The third interior surface and third exterior surface are substantially flat. The second interior surface and the third exterior surface contact each other substantially continuously in a longitudinal direction and a lateral direction, and are flat and substantially parallel to each other. The second exterior surface is contoured such that the second exterior surface is not flat and is substantially non-parallel relative to the third interior surface.

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 method for producing a bipolar plate strand comprises: providing a first and a second unipolar plate strand, the unipolar plate strands comprising a plurality of webs and a plurality of channels extending between two adjacent webs in each case, guiding the unipolar plate strands towards a rolling gap of a pair of rollers of a rolling device provided with rolling structures, local heating of one surface area of a surface of at least one of the unipolar plate strands, the surface area immediately before or upon entry of the unipolar plate strands into the rolling gap being heated to a joining temperature, and joining the unipolar plate strands at the at least one surface area to form a bipolar plate strand during transport of the unipolar plate strands through the rolling gap under the action of pressure.

A separator plate for an electrochemical system, comprising: at least one of the flanks of the bead assembly has a multiplicity of passages for directing a medium through the bead flank, and a distributing or collecting structure has a multiplicity of line ducts and a multiplicity of openings, wherein the line ducts adjoin the passages in the bead flank on an external side of the bead assembly, wherein the openings are disposed on a side of the distributing or collecting structure that faces away from the bead assembly and, are fluidically connected to a bead interior.

A separator plate for an electrochemical system, comprising: at least one of the flanks of the bead assembly has a multiplicity of passages for directing a medium through the bead flank, and a distributing or collecting structure has a multiplicity of line ducts and a multiplicity of openings, wherein the line ducts adjoin the passages in the bead flank on an external side of the bead assembly, wherein the openings are disposed on a side of the distributing or collecting structure that faces away from the bead assembly and, are fluidically connected to a bead interior.

In this fuel cell, a cathode-side porous film that covers a cathode electrode is interposed between the cathode electrode and an air supply layer, the cathode electrode constituting electrolyte film/electrode structures. In addition, breathing holes are formed in the cathode-side porous film, and the air flowing through air supply passages passes through the breathing holes and is supplied to the cathode electrode.