FLOW FIELDS FOR USE WITH AN ELECTROCHEMICAL CELL
A flow field for use in an electrochemical cell is disclosed. The flow field includes a porous metallic structure including an inlet port and a plurality of channels stamped in the structure. The plurality of channels is in fluid communication with the inlet port to receive a reactant gas and configured to cause the reactant gas to diffuse through the porous metallic structure between adjacent channels.
1 . A flow field for use in an electrochemical cell comprising:
a porous metallic structure including an inlet port;
a plurality of features stamped in the structure, the plurality of features being in fluid communication with the inlet port to receive a reactant gas and configured to cause the reactant gas to flow through the porous metallic structure between adjacent features.
2 . The flow field of claim 1 , wherein the porous metallic structure includes a metallic foam.
3 . The flow field of claim 1 , wherein the structure includes a first edge and a second edge, wherein the inlet port is disposed on the first edge and an outlet port is disposed on the second edge.
4 . The flow field of claim 1 , wherein the plurality of features are a plurality of channels.
5 . The flow field of claim 4 , wherein a first set of the plurality of channels is offset from a second set of the plurality channels, and wherein the first set of plurality of channels and the second set of the plurality of channels terminate within the porous metallic structure.
6 . The flow field of claim 4 , wherein each of the plurality of channels have a semi-circular cross-section, and wherein a first set of the plurality of channels has an alternative arrangement relative to a second set of the plurality of channels.
7 . The flow field of claim 4 , wherein a dimple is formed about each of the plurality of channels.
8 . The flow field of claim 4 , wherein the plurality of channels have a zig-zag configuration.
9 . The flow field of claim 4 , wherein the plurality of channels are arranged to form a cross-hatch configuration.
10 . The flow field of claim 4 , wherein each of the plurality of channels has a semi-circular cross-section, and wherein a first set of the plurality of channels has an alternative arrangement than a second set of the plurality of channels.
11 . The flow field of claim 1 , further including a plurality of lands, wherein each land is disposed between adjacent features stamped in the metallic structure.
12 . The flow field of claim 1 , wherein the plurality of features are evenly distributed and sized to control the pressure drop across the flow field.
13 . The flow field of claim 1 , wherein the plurality of features are non-uniformly distributed to and configured to preferentially skew gas flow.
14 . An electrochemical cell comprising:
a first bipolar plate;
a second bipolar plate;
a membrane electrode assembly comprising a cathode, an anode, and a polymer membrane disposed between the cathode and the anode;
at least one flow field disposed between one of the first bipolar plate and the second bipolar plate and the membrane electrode assembly, the flow field being formed of a porous metallic structure having a plurality of channels stamped therein.
15 . The electrochemical cell of claim 14 , wherein the surface is a longitudinally extending surface facing towards the membrane electrode assembly.
16 . The electrochemical cell of claim 14 , wherein the porous metallic structure includes a metallic foam.
17 . The electrochemical cell of claim 14 , wherein the flow field includes a plurality of lands disposed between each of the plurality of channels, wherein the plurality of lands and the plurality of channels are sized to reduce the thickness of the electrochemical cell.
18 . A method of fabricating an open, porous flow field for use in an electrochemical cell, the method comprising:
selecting a porous metallic material having greater than about 70% void volume; and
stamping a plurality of channels into the metallic material.
19 . The method of claim 18 , wherein the porous metallic material comprises a metallic foam.
20 . The method of claim 18 , providing an inlet port and an outlet port on opposing edges of the metallic material, wherein the plurality of channels are arranged to be in fluid communication with the inlet port and the outlet port.