Various embodiments include fuel cell interconnects having a fuel distribution portion having an inlet opening, a fuel collection portion having an outlet opening, and a primary fuel flow field containing channels, wherein the fuel distribution portion comprises at least one raised feature defining a fuel distribution flow path, and the fuel distribution flow path is not continuous with the channels in the primary fuel flow field. The at least one raised feature may include, for example, a network of ribs and/or dots. Further embodiments include interconnects having a fuel distribution portion with a variable surface depth to provide variable flow restriction and/or a plenum with variable surface depth and raised a raised relief feature on the cathode side, and/or varying flow channel depths and/or rib heights adjacent a fuel hole.

A bipolar plate (100) for a fuel cell includes at least one profiled flow field (120) with at least two flow field channels (121, 122, 123, 124) and an associated inlet channel (111, 112, 113, 114) and an associated outlet channel (131, 132, 133, 134) for each of the flow field channels (121, 122, 123, 124). Here, different inlet channels (111, 112, 113, 114) are of different lengths, and different outlet channels (131, 132, 133, 134) are of different lengths. The bipolar plate (100) is characterized in that the inlet channels and/or the outlet channels (131, 132, 133, 134) are dimensioned in such a way that the pressure loss is equal via each channel which is composed of one of the flow field channels (121, 122, 123, 124), the associated inlet channel (111, 112, 113, 114) and the associated outlet channel (131, 132, 133, 134), as long as a predefined mass flow change takes place in each of the flow field channels (121, 122, 123, 124).

A bipolar plate (100) for a fuel cell includes at least one profiled flow field (120) with at least two flow field channels (121, 122, 123, 124) and an associated inlet channel (111, 112, 113, 114) and an associated outlet channel (131, 132, 133, 134) for each of the flow field channels (121, 122, 123, 124). Here, different inlet channels (111, 112, 113, 114) are of different lengths, and different outlet channels (131, 132, 133, 134) are of different lengths. The bipolar plate (100) is characterized in that the inlet channels and/or the outlet channels (131, 132, 133, 134) are dimensioned in such a way that the pressure loss is equal via each channel which is composed of one of the flow field channels (121, 122, 123, 124), the associated inlet channel (111, 112, 113, 114) and the associated outlet channel (131, 132, 133, 134), as long as a predefined mass flow change takes place in each of the flow field channels (121, 122, 123, 124).

A bipolar plate for a fuel cell having two profiled separator plates with channels for reaction gases and coolant, wherein the channels for a reaction gas or both reaction gases have a smaller width in an inlet region of the active region than in the remaining sub-region of the active region, wherein the width thereof continuously increases from the beginning to the end of the inlet region. Supports between the channels have a greater width than in the remaining sub-region of the active region, wherein the sum of the width of the channels and the width of the supports is constant, and the width of the channels and the supports is constant in the entire remaining sub-region.

A bipolar plate for a fuel cell having two profiled separator plates with channels for reaction gases and coolant, wherein the channels for a reaction gas or both reaction gases have a smaller width in an inlet region of the active region than in the remaining sub-region of the active region, wherein the width thereof continuously increases from the beginning to the end of the inlet region. Supports between the channels have a greater width than in the remaining sub-region of the active region, wherein the sum of the width of the channels and the width of the supports is constant, and the width of the channels and the supports is constant in the entire remaining sub-region.

A separator for a fuel cell having a flow channel including a transverse channel and a longitudinal channel formed therein, the transverse channel having a pair of opposed side walls, and a first pattern and a second pattern alternately spaced and arranged in the transverse channel is provided. Each of the first pattern and the second pattern is a column-shaped three-dimensional structure having a polygonal transverse section. The first pattern and the second pattern are arranged in the transverse channel so as to have a shape of the transverse sections being rotated 180° relative to each other. First spacing distances from each of the first pattern and the second pattern to a first side wall of the pair of opposed side walls of the transverse channel are different.

A separator for a fuel cell having a flow channel including a transverse channel and a longitudinal channel formed therein, the transverse channel having a pair of opposed side walls, and a first pattern and a second pattern alternately spaced and arranged in the transverse channel is provided. Each of the first pattern and the second pattern is a column-shaped three-dimensional structure having a polygonal transverse section. The first pattern and the second pattern are arranged in the transverse channel so as to have a shape of the transverse sections being rotated 180° relative to each other. First spacing distances from each of the first pattern and the second pattern to a first side wall of the pair of opposed side walls of the transverse channel are different.

An illustrative example fuel cell assembly includes at least one cooler and a plurality of fuel cells each having an anode and a cathode. Each of the anodes includes an anode flow plate configured to allow fuel to flow through the anode. The anode flow plates have a respective flow resistance that varies among at least some of the anodes based on a distance between the corresponding anode and the cooler.

An illustrative example fuel cell assembly includes at least one cooler and a plurality of fuel cells each having an anode and a cathode. Each of the anodes includes an anode flow plate configured to allow fuel to flow through the anode. The anode flow plates have a respective flow resistance that varies among at least some of the anodes based on a distance between the corresponding anode and the cooler.

An electrolyzer or unitized regenerative fuel cell has a flow field with at least one channel, wherein the cross-sectional area of the channel varies along at least a portion of the channel length. In some embodiments the channel width decreases along at least a portion of the length of the channel according to a natural exponential function. The use of this type of improved flow field channel can improve performance and efficiency of operation of the electrolyzer device.