A sealing part has an outer peripheral point of the sealing part within a range from 0 degree to 90 degrees around a center point of the sealing part relative to a stacking direction, and that is located at a distance of a first length L1 from the center point. Each point on the outer peripheral line within a first range satisfies L2≤L1, where L2 is a second length that is a distance from the center point to that point. Each point on the outer peripheral line within a second range satisfies L3<L1, where L3 is a distance from the center point to that point, and is located on the opposite side of the outer peripheral point from the center point or at the same position as the outer peripheral point in the direction perpendicular to the stacking direction.

A sealing part has an outer peripheral point of the sealing part within a range from 0 degree to 90 degrees around a center point of the sealing part relative to a stacking direction, and that is located at a distance of a first length L1 from the center point. Each point on the outer peripheral line within a first range satisfies L2≤L1, where L2 is a second length that is a distance from the center point to that point. Each point on the outer peripheral line within a second range satisfies L3<L1, where L3 is a distance from the center point to that point, and is located on the opposite side of the outer peripheral point from the center point or at the same position as the outer peripheral point in the direction perpendicular to the stacking direction.

A unit cell for a fuel cell is provided. The unit cell includes an insert including a Membrane-Electrode Assembly having a first pair of electrode layers formed on a first surface of a polymer electrolyte membrane and a second pair of electrode layers formed on a second surface of the polymer electrolyte membrane, an elastomer frame bonded at a rim of the insert in an outer area of the insert, the elastomer frame having a reaction surface through-hole in which the insert is disposed formed therein and having a plurality of frame manifold through-holes, through which a reactant gas can flow or be discharged, formed at both sides of and spaced apart from the reaction surface through-hole, and a pair of separators, each separator disposed on a respective side of the insert and the elastomer frame.

A unit cell for a fuel cell is provided. The unit cell includes an insert including a Membrane-Electrode Assembly having a first pair of electrode layers formed on a first surface of a polymer electrolyte membrane and a second pair of electrode layers formed on a second surface of the polymer electrolyte membrane, an elastomer frame bonded at a rim of the insert in an outer area of the insert, the elastomer frame having a reaction surface through-hole in which the insert is disposed formed therein and having a plurality of frame manifold through-holes, through which a reactant gas can flow or be discharged, formed at both sides of and spaced apart from the reaction surface through-hole, and a pair of separators, each separator disposed on a respective side of the insert and the elastomer frame.

The invention relates to a bipolar plate (10) for a fuel cell stack. The bipolar plate (10) respectively has two profiled separator plates (12, 14) respectively having an active area (16) and two distribution areas (18, 20) for supplying and discharging reaction gases and coolant to or from the active area (16), wherein the separator plates (12, 14) are designed and arranged on top of each other such that the respective bipolar plate (10) has separate channels (28, 30, 32) for the reaction gases and the coolant, which channels connect ports (22, 24, 26) for reaction gases and coolant of both distribution areas (18, 20) to each other. In the mounted fuel cell stack, the channels (28, 30) for the reaction gases are respectively bordered by a surface of a separator plate (12, 14) and a surface of a gas diffusion layer (58). It is provided that the bipolar plate (10) have an impermeable first dividing plate (38), which respectively divides the channels (28) for a reaction gas in an inlet area (40) of the active area (16) into two volume areas and extends in the flow direction (42) of the reaction gas, wherein only one volume area of the channel (28) is adjacent to the gas diffusion layer (58). The subject matter of the invention is also a fuel cell stack with such bipolar plates (10), as well as a fuel cell system with a fuel cell stack according to the invention.

The invention relates to a bipolar plate (10) for a fuel cell stack. The bipolar plate (10) respectively has two profiled separator plates (12, 14) respectively having an active area (16) and two distribution areas (18, 20) for supplying and discharging reaction gases and coolant to or from the active area (16), wherein the separator plates (12, 14) are designed and arranged on top of each other such that the respective bipolar plate (10) has separate channels (28, 30, 32) for the reaction gases and the coolant, which channels connect ports (22, 24, 26) for reaction gases and coolant of both distribution areas (18, 20) to each other. In the mounted fuel cell stack, the channels (28, 30) for the reaction gases are respectively bordered by a surface of a separator plate (12, 14) and a surface of a gas diffusion layer (58). It is provided that the bipolar plate (10) have an impermeable first dividing plate (38), which respectively divides the channels (28) for a reaction gas in an inlet area (40) of the active area (16) into two volume areas and extends in the flow direction (42) of the reaction gas, wherein only one volume area of the channel (28) is adjacent to the gas diffusion layer (58). The subject matter of the invention is also a fuel cell stack with such bipolar plates (10), as well as a fuel cell system with a fuel cell stack according to the invention.

Fuel cell assemblies comprising at least one thermally compensated coolant channel are provided. The thermally compensated coolant channel has a cross-sectional area that decreases in the coolant flow direction along at least a portion of the channel length. In some embodiments, such thermally compensated coolant channels can be used to provide substantially uniform heat flux, and substantially isothermal conditions, in fuel cells operating with substantially uniform current density.

Fuel cell assemblies comprising at least one thermally compensated coolant channel are provided. The thermally compensated coolant channel has a cross-sectional area that decreases in the coolant flow direction along at least a portion of the channel length. In some embodiments, such thermally compensated coolant channels can be used to provide substantially uniform heat flux, and substantially isothermal conditions, in fuel cells operating with substantially uniform current density.

The present invention provides a fuel cell and a cell unit thereof, and a cell stack structure body. The cell unit comprises: a first separator and a second separator opposite to each other, as well as a membrane electrode assembly laminated between the first and the second separators. The cell unit has a plurality of openings for fuel fluid, a plurality of openings for cooling medium, and a plurality of openings for oxidizing fluid; these openings pass through the first separator, the second separator, and the membrane electrode assembly from a surface extending from the cell unit, wherein at least one opening for fuel fluid, at least one opening for cooling medium, and at least one opening for oxidizing fluid are distributed in a central region of the cell unit.

The present invention provides a fuel cell and a cell unit thereof, and a cell stack structure body. The cell unit comprises: a first separator and a second separator opposite to each other, as well as a membrane electrode assembly laminated between the first and the second separators. The cell unit has a plurality of openings for fuel fluid, a plurality of openings for cooling medium, and a plurality of openings for oxidizing fluid; these openings pass through the first separator, the second separator, and the membrane electrode assembly from a surface extending from the cell unit, wherein at least one opening for fuel fluid, at least one opening for cooling medium, and at least one opening for oxidizing fluid are distributed in a central region of the cell unit.