Fuel cell stack and bipolar plate assembly

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, wherein the first 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.

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, 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 assembly (MEA) and is arranged to electrically isolate the first and the second bipolar plate assembly
• manufacturing at least one of the bipolar plate assemblies by fastening a first flow field plate and a second flow field plate on top of each other, wherein the first flow field plate is manufactured such that the final 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

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 each bipolar plate assembly has a first flow field plate and a second flow field plate, which are fastened on top of each other, and wherein at least one of the bipolar plate assemblies is a bipolar plate assembly for a fuel cell or a fuel cell stack in which the bipolar plate assembly has a first area and has at least one second area, the method comprising

• sandwiching the at least one membrane-electrode-subgasket assembly between at least the first and second bipolar plate assembly, and
• after the sandwiching step, cutting away a peripheral portion of at least one first flow field plate for providing a fuel cell stack with at least one bipolar plate assembly, which 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 (22).