Water removal features for PEMfc stack manifolds
A bipolar plate includes angled facets oriented to form V-shaped projections on the plate edge. Liquid leaving the reactant channels is drawn back into the V-shaped grooves of the projections, leaving no liquid to obstruct the channel exit openings. The bipolar plate includes one portion of the bipolar plate offset from another portion of the bipolar plate so as to expose the reactant channels. The liquid is drawn toward the end portions of the reactant channels by capillary forces, while the gas flows can exit near the beginning of the offset portion. A fuel cell stack includes angled facets that are rotated to lie in the plane of the bipolar plate edges. The edges are chamfered so the channel exit openings of the reactant channels are at the tip portions thereof, thus allowing the liquid to flow away from the channel exit openings and the gas to exit freely.
1. A bipolar plate for use in conjunction with a fuel cell, comprising:
an edge portion of the bipolar plate;
at least one substantially V-shaped projection extending away from the edge portion, the projection having first and second side surfaces;
at least one substantially V-shaped groove portion adjacent to either the first or second side surfaces of the projection;
a channel formed in the bipolar plate; and
a channel exit opening formed in either the first or second side surfaces of the projection.
2. The invention according to claim 1 , wherein the fuel cell is a proton exchange membrane fuel cell.
3. The invention according to claim 1 , wherein the channel is operable to transport liquid and gaseous materials.
4. The invention according to claim 1 , wherein a liquid exiting the channel exit opening is drawn towards the groove.
5. The invention according to claim 1 , wherein a liquid exiting the channel exit opening is drawn towards the groove by capillary forces.
6. The invention according to claim 1 , further comprising a plurality of projections.
7. The invention according to claim 6 , wherein the plurality of projections are substantially aligned with respect to one another.
8. The invention according to claim 1 , further comprising a plurality of grooves.
9. The invention according to claim 1 , wherein the channel exit opening extends along a tip portion of the projection.
10. The invention according to claim 1 , wherein the channel exit opening extends along a midpoint portion of the length of the first or second side surfaces of the projection.
11. The invention according to claim 1 , wherein the bipolar plate is comprised of materials selected from the group consisting of metals, plastics, and combinations thereof.
12. The invention according to claim 1 , further comprising a hydrophilic coating applied to a surface of the bipolar plate.