Method of using a water transport plate
View Patent ↗A water transport plate is provided with optimized physical characteristics to greatly improve fuel cell operation. In a preferred method of manufacturing, graphite powder, reinforcing fibers, cellulosic fibers, and a thermosetting resin are mixed with a liquid to form a slurry and showered onto a screen to form a planar sheet which is dried to form paper. The paper is cut into the desired size and is laid-up. The lay-up is laminated with pressure and heat, carbonized, and graphitized to form a water transport plate for later machining as desired. The finished water transport plate exhibits optimal physical characteristics for bubble pressure, water permeability, median pore size, porosity, thru-plane resistivity and compressive yield strength.
1. A method of using a water transport plate in a fuel cell, comprising the steps of:
providing a porous water transport plate having a maximum thru-plane resistivity of 0.04 ohm-cm, a minimum compressive yield strength of 750 psi, maximum median pore size of 3.0 microns and minimum open porosity of 30 volume percent;
filling said porous water transport plate with water; and
employing said porous water transport plate in a fuel cell for management of water therein.
2. The method of claim 1 , further comprising the steps of:
creating bubble pressure in said porous water transport plate in the range of 5 to 15 psig; and
providing water permeability of said porous water transport plate in the range of 30×10 −17 m 2 to 2,000×10 −17 m 2 .
3. The method of claim 1 , wherein said thru-plane resistivity of said porous water transport plate is approximately 0.02 ohm-cm.
4. The method of claim 1 , wherein said compressive yield strength of said porous water transport plate is approximately 1,050 psi.
5. The method of claim 1 , wherein said median pore size of said porous water transport plate is approximately 1.9 microns.
6. The method of claim 1 , wherein said open porosity of said porous water transport plate is approximately 40 volume percent.
7. The method of claim 2 , wherein said bubble pressure within said porous water transport plate is approximately 10.5 psig.
8. The method of claim 2 , wherein said water permeability through said porous water transport plate is approximately 200×10 −17 m 2 .
9. A method of using a porous water transport plate in a fuel cell, comprising the steps of:
providing a porous water transport plate having a maximum thru-plane resistivity of 0.04 ohm-cm, a minimum compressive yield strength of 750 psi, maximum median pore size of 3.0 microns and a minimum open porosity of 30 volume percent;
filling said porous water transport plate with water;
creating bubble pressure in said porous water transport plate in the range of 5 to 15 psig; and
providing water permeability of said porous water transport plate in the range of 30×10 −17 m 2 to 2,000×10 −17 m 2 ;
employing said porous water transport plate in a fuel cell for management of water therein.
10. A method of using a porous water transport plate in a fuel cell, comprising the steps of:
filling said porous water transport plate with water;
providing water permeability of said porous water transport plate in the range of 30 × 10 ( − 17 ) meters squared to 2 , 000 × 10 ( − 17 ) meters squared; and
employing said porous water transport plate in a fuel cell for management of water therein.
11. The method of claim 10 comprising creating bubble pressure in said porous water transport plate in the range of 5 to 15 psig.
12. The method of claim 11 comprising providing said porous water transport plate with a minimum open porosity of 30 volume percent.
13. The method of claim 11 comprising providing said porous water transport plate with a density of 1 . 00 - 1 . 40 gm/cubic cm.