Fuel cell stack and bipolar plate assembly

Patent metadata

Field	Value
Publication number	US-12278405-B2
Application number	US-201816489019-A
Country	US
Kind code	B2
Filing date	Feb 23, 2018
Priority date	Mar 7, 2017
Publication date	Apr 15, 2025
Grant date	Apr 15, 2025

Abstract

A bipolar plate assembly for a fuel cell or a fuel cell stack has at least a first flow field plate and a second flow field plate, wherein the first flow field plate and the second flow field plate are fastened on top of each other, wherein the bipolar plate assembly has a first area, in which an edge of the first flow field plate is flush with an edge of the second flow field plate, and has at least one second area, in which the edge of the first flow field plate is recessed from the edge of the second flow field plate. A fuel cell stack having such a bipolar plate assembly, as well as methods for manufacturing such a bipolar plate assembly or such a fuel cell stack are also provided.

First claim

The invention claimed is:

1. Bipolar plate assembly for a fuel cell or a fuel cell stack having at least a first flow field plate and a second flow field plate,
each of the first flow field plate and the second flow field plate comprising first and second sides parallel to a main plane of the bipolar plate assembly and separated by a peripheral edge extending from the first side to the second side, the peripheral edge of the first flow field plate and the peripheral edge of the second flow field plate being perpendicular to the main plane,
wherein one of the first and second sides of the first flow field plate and one of the first and second sides of the second flow field plate face each other and are fastened to each other, and both the first flow field plate and the second flow field plate have a reactant flow field at one side and a cooling fluid flow field on another side, wherein, in the bipolar plate assembly, the cooling fluid flow field of the first flow field plate and the cooling fluid flow field of the second flow field plate face each other, and the reactant flow field of the first flow field plate and the reactant flow field of the second flow field plate are arranged at outside surfaces of the bipolar plate assembly,
wherein the bipolar plate assembly comprises a first area and a second area,
the first area comprises the peripheral edge of the first flow field plate being flush with the peripheral edge of the second flow field plate,
the second area comprises the peripheral edge of the first flow field plate being recessed from the peripheral edge of the second flow field plate, and
the second area further comprises the peripheral edge of the first flow field plate and the peripheral edge of the second flow field plate both being recessed relative to the peripheral edge of the first flow field plate and the peripheral edge of the second flow field plate in the first area, when viewed into the main plane.

2. Bipolar plate assembly according to claim 1 , wherein the at least one second area is provided in less than 10% of a total periphery of the flow field plate.

3. Bipolar plate assembly according to claim 1 , wherein the at least one second area is provided in a region of the bipolar plate assembly in which an aligning structure for correctly aligning at least the first flow field plate and the second flow field plate is adapted to be accommodated.

4. Fuel cell stack comprising at least a first bipolar plate assembly, at least a second bipolar plate assembly, and at least one membrane-electrode-subgasket assembly, which is sandwiched between the first and second bipolar plate assemblies, wherein the membrane-electrode-subgasket assembly comprises a proton exchange membrane, which is sandwiched between two electrodes, and a sub-gasket, which at least surrounds a periphery of the membrane-electrode assembly (MEA) and is arranged to electrically isolate the first and the second bipolar plate assembly,
wherein at least one bipolar plate assembly has at least a first flow field plate and a second flow field plate, each of the first flow field plate and the second flow field plate comprising first and second sides parallel to a main plane of the bipolar plate assembly and separated by a peripheral edge extending from the first side to the second side, the peripheral edge of the first flow field plate and the peripheral edge of the second flow field plate being perpendicular to the main plane,
wherein one of the first and second sides of the first flow field plate and one of the first and second sides of the second flow field plate face each other and are fastened to each other,
wherein the at least one bipolar plate assembly has a first area and a second area,
the first area comprises the peripheral edge of the first flow field plate being flush with the peripheral edge of the second flow field plate,
the second area comprises the peripheral edge of the first flow field plate being recessed from the peripheral edge of the second flow field plate, and
the second area further comprises the peripheral edge of the first flow field plate and the peripheral edge of the second flow field plate both being recessed relative to the peripheral edge of the first flow field plate and the peripheral edge of the second flow field plate in the first area, when viewed into the main plane.

5. Fuel cell stack according to claim 4 , wherein a subgasket of the membrane-electrode-subgasket assembly extends beyond an edge of the bipolar plate assemblies in the first area and is flush with peripheral edges of the second flow field plates of the bipolar plate assemblies in the second area.

6. Method for manufacturing a bipolar plate assembly, comprising
fastening a first flow field plate and a second flow field plate to each other, each of the first flow field plate and the second flow field plate comprising first and second sides parallel to a main plane of the bipolar plate assembly and separated by a peripheral edge extending from the first side to the second side, the peripheral edge of the first flow field plate and the peripheral edge of the second flow field plate being perpendicular to the main plane, so that one of the first and second sides of the first flow field plate and one of the first and second sides of the second flow field plate face each other, and
wherein, upon fastening the first flow field plate to the second flow field plate to form a fastened first flow field plate and second flow field plate assembly, the fastened first flow field plate and second flow field plate assembly comprises a first area and a second area, the first area comprises the peripheral edge of the first flow field plate being flush with the peripheral edge of the second flow field plate, the second area comprises the peripheral edge of the first flow field plate being recessed from the peripheral edge of the second flow field plate, and the second area further comprises the peripheral edge of the first flow field plate and the peripheral edge of the second flow field plate both being recessed relative to the peripheral edge of the first flow field plate and the peripheral edge of the second flow field plate in the first area, when viewed into the main plane.

7. Method according to claim 6 , wherein a recessed portion of the peripheral edge of the first flow field plate is manufactured by cutting away a peripheral portion of the first flow field plate after the first flow field plate has been formed by molding or stamping.

8. Method according to claim 6 , wherein a recessed portion of the peripheral edge of the first flow field plate is manufactured during the molding or stamping process.

9. Method for manufacturing a fuel cell stack, comprising at least one membrane-electrode-subgasket assembly and at least a first bipolar plate assembly and a second bipolar plates assembly, wherein at least one of the bipolar plate assemblies is a bipolar plate assembly that has at least a first flow field plate and a second flow field plate, each of the first flow field plate and the second flow field plate comprising first and second sides parallel to a main plane of the bipolar plate assembly and separated by a peripheral edge extending from the first side to the second side, the peripheral edge of the first flow field plate and the peripheral edge of the second flow field plate being perpendicular to the main plane, the method comprising
sandwiching the at least one membrane-electrode-subgasket assembly between the at least first and second bipolar plate assemblies, wherein the membrane-electrode-subgasket assembly comprises a proton exchange membrane, which is sandwiched between two electrodes, and a sub-gasket, which at least surrounds a periphery of the membrane-electrode

Assignees

• Powercell Sweden Ab
• Reinz Dichtungs Gmbh

Inventors

• Flink Johan
• Gaugler Bernd
• Kunz Claudia

Classifications

• H01M8/1004

  characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence) · CPC title

• H01M8/0267 Primary

  having heating or cooling means, e.g. heaters or coolant flow channels · CPC title

• H01M8/2484

  characterised by external manifolds · CPC title

• H01M8/10

  Fuel cells with solid electrolytes · CPC title

• H01M8/0202

  Collectors; Separators, e.g. bipolar separators; Interconnectors · CPC title