Interconnector arrangement for a fuel cell stack

1. An interconnector arrangement for a fuel cell stack, which can be brought into electrical contact with at least one membrane electrode assembly and which is arranged to separate a cathode flow field of the fuel cell stack from an anode flow field of the fuel cell stack, wherein the interconnector arrangement comprises

a flow field plate separating the cathode flow field from the anode flow field, wherein the flow field plate has an undulating, zigzag-shaped or meandering cross section defining at least one bulge defining a hollow space not directly opposite an electrode,

peripheral seals sealing the flow fields, and

at least one internal seal separating the hollow space from the anode flow field and from the cathode flow field such that a flow of gas through the hollow space may not be more than five percent of a flow of gas through the cathode or anode flow field.

2. The interconnector arrangement of claim 1 , wherein the hollow space cannot communicate with the anode flow field and the cathode flow field.

3. The interconnector arrangement of claim 1 , wherein the hollow space is elongate and extends parallel to a flow-direction (x) defined by the cathode flow field or the anode flow field.

4. The interconnector arrangement of claim 1 , wherein the bulge defining the hollow space is bridged by a blind plate as the seal so that the hollow space is enclosed between the flow field plate and blind plate.

5. The interconnector arrangement of claim 1 , wherein the hollow space is situated in a border region of the interconnector arrangement.

6. The interconnector arrangement claim 1 , wherein the hollow space is sealed off at least partially by force closure.

7. A fuel cell stack comprising art interconnector arrangement of claim 1 .

8. An interconnector arrangement for a fuel cell stack, wherein the fuel cell stack comprises

a first fuel cell comprising a membrane electrode assembly ( 52 ) having at least a cathode ( 16 ), an anode ( 12 ), an electrolyte ( 14 ) between the cathode and anode, an anode flow field ( 60 ) on the side of the anode opposite the electrolyte, a cathode flow field ( 58 ) on the side of the anode opposite the electrolyte,

a second fuel cell comprising at membrane electrode assembly ( 52 ) having at least a cathode ( 16 ), an anode ( 12 ), an electrolyte ( 14 ) between the cathode and anode, an anode flow field ( 60 ) on the side of the anode opposite the electrolyte, a cathode flow field ( 58 ) on the side of the anode opposite the electrolyte,

wherein peripheral seals ( 20 , 30 ) are provided for sealing the periphery of the flow fields,

wherein the anode flow field of the first fuel cell is adjacent the cathode fuel field of the second fuel cell and said flow fields are separated by a flow field plate ( 26 ) having an undulating, zigzag-shaped or meandering cross section forming bulges in the flow fields,

wherein the flow field plate includes at least one bulge which is not directly facing an electrode, the bulge thus defining a hollow space ( 54 ) which functionally does not supply gas to the electrode, and

an internal gas seal ( 56 ) between the flow field and the hollow space ( 54 ).

9. The interconnector arrangement of claim 8 , wherein the bulge defining the hollow space is bridged by a blind plate as the seal so that the hollow space is enclosed between the flow field plate and blind plate.

10. An interconnector arrangement for a fuel cell stack, wherein the fuel cell stack comprises

a first fuel cell comprising a membrane electrode assembly ( 52 ) having at least a cathode ( 16 ), an anode ( 12 ), an electrolyte ( 14 ) between the cathode and anode, an anode flow field ( 60 ) on the side of the anode opposite the electrolyte, a cathode flow field ( 58 ) on the side of the anode opposite the electrolyte,

a second fuel cell comprising at membrane electrode assembly ( 52 ) having at least a cathode ( 16 ), an anode ( 12 ), an electrolyte ( 14 ) between the cathode and anode, an anode flow field ( 60 ) on the side of the anode opposite the electrolyte, a cathode flow field ( 58 ) on the side of the anode opposite the electrolyte,

wherein the anode flow field of the first fuel cell is adjacent the cathode fuel field of the second fuel cell and said flow fields are separated by a flow field plate ( 26 ) having an undulating, zigzag-shaped or meandering cross section forming bulges in the flow fields,

wherein a peripheral seal ( 20 ) is provided for sealing the periphery of the anode flow field,

wherein the flow field plate ( 26 ) defines at least one bulge in the anode side of the plate which is not directly facing the anode ( 12 ), the bulge thus defining a hollow space ( 54 ) outside the region in which flow of fuel gas supplies hydrogen to the electrode, and

an internal gas seal ( 56 ) sealing said hollow space ( 54 ) blocking at least 95% of said fuel gas from entering into and flowing through said hollow space ( 54 ).

11. The interconnector arrangement of claim 10 , wherein the bulge defining the hollow space is bridged by a blind plate as the seal so that the hollow space is enclosed between the flow field plate and blind plate.