This disclosure relates to a sealing configuration for a fuel cell having external manifolds.
A fuel cell includes multiple cells arranged in a cell stack assembly. In one type of fuel cell, each cell includes a membrane electrode assembly (MEA) arranged between an anode and a cathode. The anode and cathode include passages that respectively carry oxidant and reactant to the MEA to produce electricity (and water as a byproduct). In one type of arrangement, the passages are provided in porous water transport plates that permit the water to pass through the plate.
Heat is generated during fuel cell operation. Consequently, coolant passages are provided in the anode and/or cathode to remove heat in some types of cell stack assemblies. In one type of fuel cell, the oxidant, reactant and coolant are fluidly communicated to and from the anode and cathode using external manifolds. In the case of external manifolds, the passages in the anode and cathode water transport plates are routed from one edge of the plate to another edge to allow fluids to flow between the external manifolds. Typically, discretely placed gasket seals are arranged at the interface between the adjoining plates and the MEA to maintain separation of the oxidant and reactant and minimize leakage from the cell stack assembly. Some gaskets may be configured in an undesirable manner that adversely affects fuel cell operation and/or efficiency.
A fuel cell plate is disclosed that includes a structure having opposing sides bounded by a periphery providing at least one edge. Gas flow channels are arranged on the one side and arranged within a perimeter that is spaced inboard from the periphery to provide a first gasket surface between the perimeter and the periphery. Inlet and outlet flow channels are arranged on the other side and extend to the periphery and are configured to provide gas at the at least one edge. Holes extend through the structure and fluidly interconnect the inlet and outlet flow channels to the gas flow channels. In one example, the fuel cell plate is a water transport plate in a fuel cell having external manifolds that supply fluid to the plate.
The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Fluids are introduced to and expelled from the cell stack assembly 12 using various manifolds. An oxidant source 36 supplies an oxidant, such as hydrogen, to an oxidant inlet manifold 24. Oxidant flows through flow channels in the anode 16 and is collected at an oxidant outlet manifold 26. A reactant source 38 provides a reactant, such as air, to a reactant inlet manifold 28. The reactant flows through flow channels in the cathode 18 and is collected by a reactant outlet manifold 30. The cell stack assembly 12 generates heat as the oxidant and reactant interact with one another. As a result, a coolant source 40 may be used to provide a coolant, such as water, to cool the fuel cell 10. Coolant is supplied through a coolant inlet manifold 32 and flows through flow channels in the anode 16 and/or cathode 18 and is collected by the coolant outlet manifold 34. In the example shown, the reactant inlet manifold 28 and coolant inlet manifold 32 are integrated with one another. The reactant outlet manifold 30 and coolant outlet manifold 34 are also integrated with one another.
A portion of the cell stack assembly 12 is shown in more detail in
First, second and third gaskets 52, 54, 56 are used as seals between the anode 16, cathode 18 and subgasket 50. Unlike other prior art gasket arrangements, the first, second and third gaskets 52, 54, 56 do not extend across the flow channels provided in the anode 16 and cathode 18.
The arrangement of the first, second and third gaskets 52, 54, 56 may be better appreciated by reference to
With reference to
In the example cell stack assembly 12, the second side 62 includes coolant inlet and outlet channels 78, 80 in fluid communication with the coolant flow channels 82 arranged on the second side 62. The coolant inlet and outlet channels 78, 80 extend to opposing edges of the cathode water transport plate 58 remote from one another and are respectively in fluid communication with the coolant inlet and outlet manifolds 32, 34 (
The reactant flow channels 68 provide a reactant flow channel perimeter 72 arranged inboard from the edges of the cathode water transport plate 58. A first gasket surface 61 is provided on the first side 60 between the reactant flow channel perimeter 72 and the edges of the cathode water transport plate 58 at its outer periphery. Inlet and outlet perimeters 69, 71 are respectively provided about the reactant inlet and outlet channels 64, 66. In the example, the inlet and outlet perimeters 69, 71 extend to the nearby edges. The coolant inlet and outlet flow channels and coolant flow channel 78, 80, 82 provide a coolant perimeter 73. A second gasket surface 63 is arranged between the inlet and outlet perimeters 69, 71 and the coolant perimeters 73 and the cathode water transport plate 58 edges at its periphery on the second side 62.
The first gasket 52 is provided on the first gasket surface 61 such that the first gasket 52 does not overlap the reactant flow channels 68. The first gasket 52 seals against the subgasket 50. The second gasket 54 is arranged on the second gasket surface 63 such that the second gasket 54 does not overlap the reactant inlet and outlet channels 64, 66 and the coolant inlet and outlet flow channels and coolant flow channels 78, 80, 82.
With reference to FIGS. 2B and 5-8, the anode 16 is shown in more detail. The anode 16 is constructed from a porous anode water transport plate 84, for example. The anode water transport plate 84 includes spaced apart first and second sides 86, 88 extending to a periphery having edges. Oxidant inlet channels 90 extend to an edge 100 for communication with the oxidant inlet manifold 24 (
The oxidant flow channels 94 provide an oxidant flow channel perimeter 98 arranged inboard from the edges of the anode water transport plate 84. A first gasket surface 104 is provided on the first side 86 between the oxidant flow channel perimeter 98 and the edges of the anode water transport plate 84 at its outer periphery. Inlet and outlet perimeters 97, 99 are respectively provided about the reactant oxidant inlet and outlet channels 9092. In the example, the inlet and outlet perimeters 97, 99 extend to the nearby edges. A second gasket surface 106 is arranged between the inlet and outlet perimeters 97, 99 and the anode water transport plate 84 edges at its periphery on the second side 88.
The second gasket 54 is provided on the first gasket surface 104 such that the second gasket 54 does not overlap the oxidant inlet and outlet channels 90, 92. The second gasket 54 seals against the second gasket surface 63 on the second side 62 of the cathode water transport plate 58. The third gasket 56 is arranged on the second gasket surface 106 such that the third gasket 56 does not overlap the oxidant flow channels 94. The third gasket 56 seals against the subgasket 50.
Although a preferred embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content.
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/US09/63701 | 11/9/2009 | WO | 00 | 3/15/2012 |