Fuel-cell membrane-subgasket assemblies comprising coated subgaskets, and fuel-cell assemblies and fuel-cell stacks comprising the fuel-cell membrane subgasket assemblies
View Patent ↗Fuel-cell membrane-subgasket assemblies may include an electrolyte membrane and a coated subgasket overlying the electrolyte membrane around a perimeter of the electrolyte membrane so as to define an active area inside the perimeter. The coated subgasket may comprise a subgasket body formed from a subgasket material. At least one side of the coated subgasket includes a subgasket coating layer containing or formed from a coating material such as metals, ceramics, polymers, polymer composites, or other hard coatings. Fuel-cell assemblies may include gas diffusion media, a bipolar plate, and a fuel-cell membrane-subgasket assembly having a coated subgasket. Fuel-cell stacks may include clamping plates, unipolar endplates, and a plurality of individual fuel-cell assemblies, at least one of which includes a fuel-cell membrane-subgasket assembly having a coated subgasket.
1. A fuel-cell membrane-subgasket assembly comprising:
an electrolyte membrane; and
a coated subgasket overlying a perimeter of the electrolyte membrane, the coated subgasket defining an active area of the electrolyte membrane inside the perimeter of the electrolyte membrane,
wherein:
the coated subgasket comprises a subgasket body formed from polyethylene terephthalate;
the subgasket body has a first subgasket side facing the electrolyte membrane and a second subgasket side opposite the first subgasket side;
at least one of the first subgasket side of the subgasket body and the second subgasket side of the subgasket body comprises a subgasket coating layer over the subgasket material;
the subgasket coating layer comprises a subgasket coating material that increases bending stiffness of the subgasket body, degradation resistance of the subgasket body in the presence of moisture, and puncture resistance of the subgasket body; and
the subgasket coating material is titanium nitride.
2. The fuel-cell membrane-subgasket assembly of claim 1 , wherein:
the subgasket coating layer has a thickness of from about 0.01 μm to about 20 μm;
the subgasket body has a thickness of from about 5 μm to about 200 μm; and
the ratio of the thickness of the subgasket coating layer to the thickness of the subgasket body is from about 1:2 to about 1:500.
3. The fuel-cell membrane-subgasket assembly of claim 1 , further comprising a first electrode layer and a second electrode layer, wherein:
the electrolyte membrane is coated with the first electrode layer on a first side of the electrolyte membrane and with the second electrode layer on a second side of the electrolyte membrane opposite the first side; and
the first electrode layer is interposed between the electrolyte membrane and the coated subgasket.
4. The fuel-cell membrane-subgasket assembly of claim 1 , further comprising a first gas diffusion medium, a second gas diffusion medium, a first electrode layer, and a second electrode layer, wherein:
the first electrode layer is a catalytic coating on the first gas diffusion medium;
the second electrode layer is a catalytic coating on the second gas diffusion medium; and
the coated subgasket is interposed between the first electrode layer and the electrolytic membrane.
5. A fuel cell assembly comprising:
a first gas diffusion medium;
a second gas diffusion medium;
a fuel-cell membrane-subgasket assembly interposed between the first gas diffusion medium and the second gas diffusion medium, the fuel-cell membrane-subgasket assembly comprising:
an electrolyte membrane; and
a coated subgasket overlying a perimeter of the electrolyte membrane, the coated subgasket defining an active area inside the perimeter of the electrolyte membrane,
wherein:
the coated subgasket comprises a subgasket body formed from polyethylene terephthalate;
the subgasket body has a first subgasket side facing the electrolyte membrane and a second subgasket side opposite the first subgasket side;
at least one of the first subgasket side of the subgasket body and the second subgasket side of the subgasket body comprises a subgasket coating layer over the subgasket material;
the subgasket coating layer comprises a subgasket coating material that increases bending stiffness of the subgasket body, degradation resistance of the subgasket body in the presence of moisture, and puncture resistance of the subgasket body; and
the subgasket coating material is titanium nitride;
a first electrode layer interposed between the electrolyte membrane and the first gas diffusion medium;
a second electrode layer interposed between the electrolyte membrane and the second gas diffusion medium; and
a bipolar plate having a cathode side and an anode side opposite the cathode side, the bipolar plate being in fluidic communication with the electrolyte membrane.
6. The fuel-cell assembly of claim 5 , wherein:
the first electrode layer is a catalytic coating on a first electrode surface of the electrolyte membrane; and
the first electrode layer is interposed between the coated subgasket and the electrolyte membrane.
7. The fuel-cell assembly of claim 5 , wherein:
the first electrode layer is a catalytic coating on the first gas diffusion medium; and
the coated subgasket is interposed between the first electrode layer and the electrolytic membrane.
8. A fuel cell stack comprising:
a first clamping plate;
a second clamping plate;
a first unipolar endplate positioned between the first clamping plate and the second clamping plate;
a second unipolar endplate positioned between the first unipolar endplate and the second clamping plate; and
a plurality of stacked individual fuel cell assemblies each positioned between the first unipolar endplate and the second unipolar endplate, at least one of the individual fuel cell assemblies comprising:
a first gas diffusion medium;
a second gas diffusion medium;
a fuel-cell membrane-subgasket assembly interposed between the first gas diffusion medium and the second gas diffusion medium, the fuel-cell membrane-subgasket assembly comprising:
an electrolyte membrane; and
a coated subgasket overlying a perimeter of the electrolyte membrane, the coated subgasket defining an active area inside the perimeter of the electrolyte membrane,
wherein:
the coated subgasket comprises a subgasket body formed from polyethylene terephthalate;
the subgasket body has a first subgasket side facing the electrolyte membrane and a second subgasket side opposite the first subgasket side;
at least one of the first subgasket side of the subgasket body and the second subgasket side of the subgasket body comprises a subgasket coating layer over the subgasket material;
the subgasket coating layer comprises a subgasket coating material that increases bending stiffness of the subgasket body, degradation resistance of the subgasket body in the presence of moisture, and puncture resistance of the subgasket body; and
the subgasket material is titanium nitride;
a first electrode layer interposed between the electrolyte membrane and the first gas diffusion medium;
a second electrode layer interposed between the electrolyte membrane and the second gas diffusion medium; and
a bipolar plate having a cathode side and an anode side opposite the cathode side, the bipolar plate being in fluidic communication with the electrolyte membrane,
wherein:
adjacent individual fuel cell assemblies of the plurality of stacked individual fuel cell assemblies share a common bipolar plate between a first individual fuel cell assembly and a second individual fuel cell assembly;
the cathode side of the common bipolar plate faces the first individual fuel cell assembly; and
the anode side of the common bipolar plate faces the second individual fuel cell assembly.
9. The fuel-cell stack of claim 8 , wherein:
the first electrode layer of the at least one fuel-cell assembly is a catalytic coating on a first electrode surface of the electrolyte membrane; and
the first electrode layer of the at least one fuel-cell assembly is interposed between the coated subgasket and the electrolyte membrane.
10. The fuel-cell stack of claim 8 , wherein:
the first electrode layer is a catalytic coating on the first gas diffusion medium; and
the coated subgasket is interposed between the first electrode layer and the electrolytic membrane.