Process for producing carbon-cladded composite bipolar plates for fuel cells
The present invention provides a process for making a carbon-cladded composite composition for use as a fuel cell flow field plate or bipolar plate. In one preferred embodiment, the process comprises (a) providing a layer of conductive filler-resin composite having a first and a second primary surface; (b) depositing two clad layers of conductive carbon or graphite material onto the two primary surfaces, respectively, to produce a clad-composite-clad (three-layer) precursor structure; (c) creating flow field channels on the two primary exterior surfaces of the three-layer precursor; and (d) curing or solidifying the resin to form the desired bipolar plate. These steps are preferably integrated into a continuous roll-to-roll process for the mass production of bipolar plates. The conductive carbon or graphite material preferably comprises particles selected from the group consisting of carbon fibers, carbon nano-tubes, graphitic nano-fibers, nano-scaled graphene plates, carbon blacks, fine graphite powder, and combinations thereof.
1 . A process for producing a precursor composition to a carbon-cladded composite intended for use as a fuel cell flow field plate or bipolar plate, said process comprising:
(a) providing a layer of conductive filler-resin composite having a first and a second primary surface; and
(b) dispensing a first clad of conductive carbon or graphite material onto said first primary surface of the composite layer to form a precursor two-layer structure wherein said resin remains in a melt, uncured fluid, or wet state.
2 . The process of claim 1 further comprising:
(c) creating a fluid flow channel onto a planar outer surface on the first clad side of the precursor two-layer structure; and
(d) curing or solidifying said resin to form a carbon-cladded composite flow field plate.
3 . The process of claim 1 further comprising a step of dispensing a second clad of conductive carbon or graphite material onto said second primary surface of the composite layer to form a precursor three-layer structure.
4 . The process of claim 3 further comprising:
(e) creating fluid flow channels onto two planar outer surfaces of the precursor three-layer structure; and
(f) curing or solidifying said resin to form a carbon-cladded composite bipolar plate.
5 . A process for producing a precursor composition to a carbon-cladded composite intended for use as a fuel cell bipolar plate, said process comprising:
(g) providing a first precursor two-layer structure having a first clad layer and a first conductive filler-resin layer;
(h) providing a second precursor two-layer structure having a second clad layer and a second conductive filler-resin layer; and
(c) merging said first conductive filler-resin layer and second conductive filler-resin layer to obtain a three-layer precursor composition comprising an uncured or un-solidified resin.
6 . The process of claim 5 further comprising
(i) creating fluid flow channels onto two planar outer surfaces of the precursor three-layer composition; and
(j) curing or solidifying said resin to form a carbon-cladded composite bipolar plate.
7 . The process of claim 5 wherein steps (g) and (h) comprise uncoiling a precursor two-layer structure from a source roller or drum.
8 . The process of claim 7 further comprising a step of winding up said three-layer precursor structure on a roller or drum.
9 . The process of claim 1 further comprising a step of winding up said two-layer precursor structure on a roller or drum.
10 . The process of claim 3 further comprising a step of winding up said three-layer precursor structure on a roller or drum.
11 . The process of claim 4 , wherein said conductive carbon or graphite material comprises particles selected from the group consisting of carbon fibers, carbon nano-tubes, graphitic nano-fibers, nano-scaled graphene plates, carbon blacks, graphite powder, amorphous carbon, chemical vapor deposited carbon, laser-induced carbon, and combinations thereof.
12 . The process of claim 4 , wherein said resin comprises a thermoset resin selected from the group consisting of unsaturated polyester resin, vinyl ester, epoxy, phenolic resin, polyimide resin, bismaleimide resin, polyurethane resin, and combinations thereof.
13 . The process of claim 4 , wherein said conductive filler comprises a conductive material selected from the group consisting of carbon fiber, metal fiber, carbon nano-tube, graphitic nano-fiber, nano-scaled graphene plate, carbon black, metal particle, graphite powder, and combinations thereof.
14 . The process of claim 4 , wherein said conductive filler-resin composite comprises a matrix resin selected from a thermoplastic, a thermoset, a semi-interpenetrating network, an interpenetrating network, a rubber, or a combination thereof.
15 . The process of claim 4 , wherein said first clad or second clad has a thickness smaller than 10 μm.
16 . The process of claim 4 , wherein said first clad or second clad has a thickness smaller than 1 μm.
17 . The process of claim 4 , wherein said cladded composite has an electrical conductivity no less than 100 S/cm or an areal conductivity no less than 200 S/cm 2 .
18 . The process of claim 4 , wherein said step of providing a layer of conductive filler-resin composite comprises dispensing and depositing multiple layers of resin and multiple layers of conductive filler particles that overlay each other in an alternate manner.