EP1273063A1 - Article souple en graphite et electrode a cellule electrochimique presentant une conductivite electrique et thermique accrue - Google Patents
Article souple en graphite et electrode a cellule electrochimique presentant une conductivite electrique et thermique accrueInfo
- Publication number
- EP1273063A1 EP1273063A1 EP00923203A EP00923203A EP1273063A1 EP 1273063 A1 EP1273063 A1 EP 1273063A1 EP 00923203 A EP00923203 A EP 00923203A EP 00923203 A EP00923203 A EP 00923203A EP 1273063 A1 EP1273063 A1 EP 1273063A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- sheet
- channels
- article
- graphite
- assembly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/8605—Porous electrodes
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/52—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite
- C04B35/536—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite based on expanded graphite or complexed graphite
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/96—Carbon-based electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/023—Porous and characterised by the material
- H01M8/0234—Carbonaceous material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/0258—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
- H01M8/026—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant characterised by grooves, e.g. their pitch or depth
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0271—Sealing or supporting means around electrodes, matrices or membranes
- H01M8/0273—Sealing or supporting means around electrodes, matrices or membranes with sealing or supporting means in the form of a frame
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/1007—Fuel cells with solid electrolytes with both reactants being gaseous or vaporised
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/94—Products characterised by their shape
- C04B2235/945—Products containing grooves, cuts, recesses or protusions
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Definitions
- the present invention relates to an article useful in an electrode assembly for an electrochemical fuel cell.
- the inventive assembly includes an article formed of flexible graphite sheet that is fluid permeable and has enhanced isotropy with respect to thermal and electrical conductivity.
- Graphites are made up of layer planes of hexagonal arrays or networks of carbon atoms. These layer planes of hexagonally arranged carbon atoms are substantially flat and are oriented or ordered so as to be substantially parallel and equidistant to one another.
- the substantially flat, parallel equidistant sheets or layers of carbon atoms usually referred to as basal planes, are linked or bonded together and groups thereof are arranged in crystallites.
- Highly ordered graphites consist of crystallites of considerable size: the crystallites being highly aligned or oriented with respect to each other and having well ordered carbon layers. In other words, highly ordered graphites have a high degree of preferred crystallite orientation.
- graphites possess anisotropic structures and thus exhibit or possess many properties that are highly directional, especially thermal and electrical conductivity and fluid diffusion.
- graphites may be characterized as laminated structures of carbon, that is, structures consisting of superposed layers or laminae of carbon atoms joined together by weak van der Waals forces.
- two axes or directions are usually noted, to wit, the "c" axis or direction and the “a" axes or directions.
- the "c” axis or direction may be considered as the direction perpendicular to the carbon layers.
- the “a” axes or directions may be considered as the directions parallel to the carbon layers or the directions perpendicular to the "c” direction.
- the natural graphites suitable for manufacturing flexible graphite possess a very high degree of orientation.
- the bonding forces holding the parallel layers of carbon atoms together are only weak van der Waals forces.
- Graphites can be treated so that the spacing between the superposed carbon layers or laminae can be appreciably opened up so as to provide a marked expansion in the direction perpendicular to the layers, that is, in the "c" direction and thus form an expanded or intumesced graphite structure in which the laminar character of the carbon layers is substantially retained.
- Natural graphite flake which has been greatly expanded and more particularly expanded so as to have a final thickness or "c" direction dimension which is at least about 80 or more times the original "c” direction dimension can be formed without the use of a binder into cohesive or integrated flexible graphite sheets of expanded graphite, e.g. webs, papers, strips, tapes, or the like.
- the formation of graphite particles which have been expanded to have a final thickness or "c" dimension which is at least about 80 times the original "c” direction dimension into integrated flexible sheets by compression, without the use of any binding material is believed to be possible due to the excellent mechanical interlocking, or cohesion which is achieved between the voluminously expanded graphite particles.
- the sheet material has also been found to possess a high degree of anisotropy with respect to thermal and electrical conductivity and fluid diffusion, comparable to the natural graphite starting material due to orientation of the expanded graphite particles substantially parallel to the opposed faces of the sheet resulting from very high compression, e.g. roll pressing.
- Sheet material thus produced has excellent flexibility, good strength and a very high degree of orientation.
- the process of producing flexible, binderless anisotropic graphite sheet material comprises compressing or compacting under a predetermined load and in the absence of a binder, expanded graphite particles which have a "c" direction dimension which is at least about 80 times that of the original particles so as to form a substantially flat, flexible, integrated graphite sheet.
- the expanded graphite particles which generally are worm-like or vermiform in appearance, once compressed, will maintain the compression set and alignment with the opposed major surfaces of the sheet.
- the density and thickness of the sheet material can be varied by controlling the degree of compression.
- the density of the sheet material can be within the range of from about 5 pounds per cubic foot to about 125 pounds per cubic foot.
- the flexible graphite sheet material exhibits an appreciable degree of anisotropy due to the alignment of graphite particles parallel to the major opposed, parallel surfaces of the sheet, with the degree of anisotropy increasing upon roll pressing of the sheet material to increased density.
- the thickness, i.e. the direction perpendicular to the opposed, parallel sheet surfaces comprises the "c” direction and the directions ranging along the length and width, i.e. along or parallel to the opposed, major surfaces comprises the "a” directions and the thermal, electrical and fluid diffusion properties of the sheet are very different, by orders of magnitude, for the "c" and "a” directions.
- anisotropy which is directionally dependent
- anisotropy which is directionally dependent
- gasket applications where flexible graphite sheet is used as the gasket material and in use is held tightly between metal surfaces, the diffusion of fluid, e.g. gases or liquids, occurs more readily parallel to and between the major surfaces of the flexible graphite sheet.
- fluid e.g. gases or liquids
- the resistivity of anisotropic flexible graphite sheet is high in the direction transverse to the major surfaces ("c" direction) of the flexible graphite sheet, and very substantially less in the direction parallel to and between the major faces of the flexible graphite sheet ("a" direction).
- c major surfaces
- a major faces of the flexible graphite sheet
- the thermal conductivity of a flexible graphite sheet in a direction parallel to the upper and lower surfaces of the flexible graphite sheet is relatively high, while it is relatively very low in the "c" direction transverse to the upper and lower surfaces.
- a membrane electrode assembly for an electro-chemical fuel cell comprising a pair of electrodes and an ion exchange membrane positioned between the electrodes, at least one of the electrodes being formed of a sheet of a compressed mass of expanded graphite particles having a plurality of transverse fluid channels passing through the sheet between first and second opposed surfaces of the sheet, one of the opposed surfaces abutting the ion exchange membrane.
- the transverse fluid channels are formed by mechanically impacting an opposed surface of the sheet to displace graphite within the sheet at predetermined locations.
- the transverse fluid channels are adjacently positioned and separated by walls of compressed expanded graphite at least some of which permit interconnection between adjacent channels (such as by having grooves therein) to enable fluid flow therebetween.
- Figure 1 is a plan view of a transversely permeable sheet of flexible graphite having interconnected transverse channels in accordance with the present invention
- Figure 1(A) shows a flat-ended protrusion element used in making the channels in the perforated sheet of Figure 1;
- Figure 2 is a side elevation view in section of the sheet of Figure 1;
- FIGS. 2(A), (B), (C) show various suitable flat-ended configurations for transverse interconnected channels in accordance with the present invention
- Figures 3, 3(A), 3(B) show a mechanism for making the article of Figure 1;
- Figures 3(C), 3(D) show enlarged perspective views of portions of transversely permeable flexible graphite sheet in accordance with the present invention
- Figure 3(E) is a photograph of a portion of transversely permeable flexible graphite sheet corresponding to Figure 3(C);
- Figure 4 shows an enlarged sketch of an elevation view of the oriented expanded graphite particles of flexible graphite sheet material
- Figure 5 is a sketch of an enlarged elevation view of an article formed of flexible graphite sheet in accordance with the present invention.
- Figure 5, 6, 7 and 7(A) show a fluid permeable electrode assembly which includes a transversely permeable article in accordance with the present invention.
- Figure 8 is a photograph at 100X (original magnification) corresponding to a portion of the side elevation view sketch of Figure 5.
- Graphite is a crystalline form of carbon comprising atoms covalently bonded in flat layered planes with weaker bonds between the planes.
- an intercalant of, for instance, a solution of sulfuric and nitric acid
- the treated particles of graphite are hereafter referred to as "particles of intercalated graphite”.
- the particles of intercalated graphite Upon exposure to high temperature, the particles of intercalated graphite expand in dimension as much as about 80 or more times its original volume in an accordion-like fashion in the "c" direction, i.e., in the direction perpendicular to the crystalline planes of the graphite.
- the exfoliated graphite particles are vermiform in appearance, and are therefore commonly referred to as worms.
- the worms may be compressed together into flexible sheets that, unlike the original graphite flakes, can be formed and cut into various shapes and provided with small transverse openings by deforming mechanical impact.
- a common method for manufacturing graphite sheet, e.g., foil from flexible graphite is described by Shane et al. in U.S. Pat. No. 3,404,061, the disclosure of which is incorporated herein by reference.
- natural graphite flakes are intercalated by dispersing the flakes in a solution containing an oxidizing agent of, for example, a mixture of nitric and sulfuric acid.
- the intercalation solution contains oxidizing and other intercalating agents known in the art.
- Examples include those containing oxidizing agents and oxidizing mixtures, such as solutions containing nitric acid, potassium chlorate, chromic acid, potassium permanganate, potassium chromate, potassium dichromate, perchloric acid, and the like, or mixtures, such as for example, concentrated nitric acid and chlorate, chromic acid and phosphoric acid, sulfuric acid and nitric acid, or mixtures of a strong organic acid, such as trifluoroacetic acid, and a strong oxidizing agent soluble in the organic acid.
- oxidizing agents and oxidizing mixtures such as solutions containing nitric acid, potassium chlorate, chromic acid, potassium permanganate, potassium chromate, potassium dichromate, perchloric acid, and the like, or mixtures, such as for example, concentrated nitric acid and chlorate, chromic acid and phosphoric acid, sulfuric acid and nitric acid, or mixtures of a strong organic acid, such as trifluoroacetic acid, and
- the intercalating agent is a solution of a mixture of sulfuric acid, or sulfuric acid and phosphoric acid, and an oxidizing agent, i.e., nitric acid, perchloric acid, chromic acid, potassium permanganate, hydrogen peroxide, iodic or periodic acids, or the like.
- the intercalation solutions may contain metal halides such as ferric chloride, and ferric chloride mixed with sulfuric acid, or a halide, such as bromine as a solution of bromine and sulfuric acid or bromine in an organic solvent.
- any excess solution is drained from the flakes and the flakes are water-washed.
- the quantity of intercalation solution retained on the flakes after draining may range from 20 to 150 parts of solution by weight per 100 parts by weight of graphite flakes (pph) and more typically about 50 to 120 pph.
- the quantity of the intercalation solution may be limited to between 10 to 50 parts of solution per hundred parts of graphite by weight (pph) which permits the washing step to be eliminated as taught and described in U.S. Pat. No. 4,895,713, the disclosure of which is also herein incorporated by reference.
- the thus treated particles of graphite are sometimes referred to as "particles of intercalated graphite".
- the particles of intercalated graphite Upon exposure to high temperature, e.g. up to about 700°C to 1000°C and higher, the particles of intercalated graphite expand as much as about 80 to 1000 or more times its original volume in an accordion-like fashion in the c-direction, i.e., in the direction perpendicular to the crystalline planes of the constituent graphite particles.
- the expanded (or exfoliated) graphite particles are vermiform in appearance, and are therefore commonly referred to as worms.
- the worms may be compressed together into flexible sheets that, unlike the original graphite flakes, can be formed and cut into various shapes and provided with small transverse openings by deforming mechanical impact as hereinafter described.
- Flexible graphite sheet and foil are coherent, with good handling strength, and are suitably compressed, such as by roll-pressing, to a thickness of 0.003 to 0.15 inch and a density of 0.1 to 1.5 grams per cubic centimeter.
- ceramic additives can be blended with the intercalated graphite flakes as described in U.S. Patent 5,902,762 (which is incorporated herein by reference) to provide enhanced resin impregnation in the final flexible graphite product.
- the additives include ceramic fiber particles having a length of 0.15 to 1.5 millimeters. The width of the particles is suitably from 0.04 to 0.004 mm.
- the ceramic fiber particles are non-reactive and non-adhering to graphite and are stable at temperatures up to 2000°F, preferably 2500°F.
- Suitable ceramic fiber particles are formed of macerated quartz glass fibers, carbon and graphite fibers, zirconia, boron nitride, silicon carbide and magnesia fibers, naturally occurring mineral fibers such as calcium metasihcate fibers, calcium aluminum silicate fibers, aluminum oxide fibers and the like.
- a compressed mass of expanded graphite particles, in the form of a flexible graphite sheet is shown at 10.
- the flexible graphite sheet 10 is provided with channels 20, which are preferably smooth-sided as indicated at 67 in Figures 5 and 8, and which pass between the parallel, opposed surfaces 30, 40 of flexible graphite sheet 10, and are separated by walls 3 of compressed expandable graphite.
- the walls 3 are advantageously provided with grooves 5, having a depth of 1/10 to 1/3 the depth of the channels in accordance with the present invention.
- the channels 20 preferably have openings 50 on one of the opposed surfaces 30 which are larger than the openings 60 in the other opposed surface 40.
- the channels 20 can have different configurations as shown at 20' - 20"" in Figures 2(A), 2(B), 2(C) which are formed using flat-ended protrusion elements of different shapes as shown at 75, 175, 275, 375 in Figures 1(A) and 2(A), 2(B), 2(C), 2(D), suitably formed of metal, e.g. steel, and integral with and extending from the pressing roller 70 of the impacting device shown in Figure 3.
- metal e.g. steel
- the smooth flat-ends of the channel-forming protrusion elements 75, 175, 275, 375, shown at 77, 177, 277, 377, and the smooth flat ends of the groove-forming protrusion elements 675, 775, 875, 975 shown at 677, 777, 877, 977, and the smooth bearing surface 73, of roller 70, and the smooth bearing surface 78 of roller 72 (or alternatively flat metal plate 79), ensure deformation and displacement of graphite within the flexible graphite sheet, preferably such that there are no rough or ragged edges or debris resulting from the channel-forming impact.
- the groove-forming protrusion elements 675, 775, 875, 975 also result in deformation and displacement of graphite within the flexible graphite sheet.
- Preferred channel-forming protrusion elements 77 have decreasing cross- section in the direction away from the pressing roller 70 to provide larger channel openings on the side of the sheet which is initially impacted.
- the development of smooth, unobstructed surfaces 63 surrounding channel openings 60, enables the free flow of fluid into and through smooth-sided (at 67) channels 20.
- openings at one of the opposed surfaces are larger than the channel openings in the other opposed surface, e.g. from 1 to 200 times greater in area, and result from the use of protrusion elements having converging sides such as shown at 76, 276, 376.
- the transverse channels 20 are formed in the flexible graphite sheet 10 at a plurality of pre-determined locations by mechanical impact at the predetermined locations in sheet 10 using a mechanism such as shown in Figure 3 comprising a pair of steel rollers 70, 72 with one of the rollers having truncated, i.e. flat-ended, prism-shaped protrusions 75 which impact surface 30 of flexible graphite sheet 10 to displace graphite and penetrate sheet 10 to form open channels 20.
- the channel-forming protrusions 75 are bridged by groove-forming protrusions 675 which form interconnecting grooves 5 between channels 20 in a row of aligned channels concurrently with formation of channels 20 which is illustrated in the sketch of Figure 3(C) and the photograph of Figure 3(E). Additionally, groove-forming protrusion elements 675' can be included as shown in Figures 3(A), 3(B) to form interconnecting grooves 5' in a parallel row of transverse channels 20 as shown in Figure 3(D).
- both rollers 70, 72 can be provided with "out-of-register" protrusions, and a flat metal plate indicated at 79, can be used in place of smooth-surfaced roller 72.
- Figure 4 is an enlarged sketch of a sheet of flexible graphite 110 that shows a typical prior art orientation of compressed expanded graphite particles 80 substantially parallel to the opposed surfaces 130, 140.
- This orientation of the expanded graphite particles 80 results in anisotropic properties in flexible graphite sheets; i.e. the electrical conductivity and thermal conductivity of the sheet is substantially lower in the direction transverse to opposed surfaces 130, 140 ("c " direction) than in the direction ("a" direction) parallel to opposed surfaces 130, 140.
- graphite is displaced within flexible graphite sheet 10 by flat-ended (at 77) channel-forming protrusions 75 to push aside graphite as it travels to and bears against smooth surface 73 of roller 70 to disrupt and deform the parallel orientation of expanded graphite particles 80 as shown at 800 in Figure 5.
- Groove forming protrusions 675 concurrently deform the parallel orientation of expanded graphite particles.
- This region of 800, adjacent channels 20 and grooves 5 shows disruption of the parallel orientation into an oblique, non-parallel orientation is optically observable at magnifications of 100X and higher.
- Figure 6, Figure 7 and Figure 7(A) show, schematically, the basic elements of an electrochemical Fuel Cell, more complete details of which are disclosed in U.S. Patents 4,988,583 and 5,300,370 and PCT WO 95/16287 (15 June 1995) and each of which is incorporated herein by reference.
- the Fuel Cell indicated generally at 500 comprises electrolyte in the form of a plastic e.g. a solid polymer ion exchange membrane 550 catalyst coated at surfaces 601, 603, e.g. coated with platinum 600 as shown in Figure 7(A); perforated flexible graphite sheet electrodes 10 in accordance with the present invention; and flow field plates 1000, 1100 which respectively abut electrodes 10. Pressurized fuel is circulated through grooves 1400 of fuel flow field pate 1100 and pressurized oxidant is circulated through grooves 1200. hi operation, the fuel flow field plate 1100 becomes an anode, and the oxidant flow field plate 1000 becomes a cathode with the result that an electric potential, i.e.
- Fuel Cell 500 requires that the electrodes 10 be porous to the fuel and oxidant fluids, e.g. hydrogen and oxygen, to permit these components to readily pass from the grooves 1400, 1200 through electrodes 10 to contact the catalyst 600, as shown in Figure 7(A), and enable protons derived from hydrogen to migrate through ion exchange membrane 550.
- fuel and oxidant fluids e.g. hydrogen and oxygen
- channels 20 are positioned to adjacently cover grooves 1400, 1200 of the flow field plates so that the pressurized gas from the grooves passes through the smaller openings 60 of channels 20 and exits the larger openings 50 of channels 20.
- fluid from adjacent channels can flow through grooves 5 so that gas- catalyst contact adjacent the blocked channel is maintained.
- the initial velocity of the gas at the smaller openings 60 is higher than the gas flow at the larger openings 50 with the result that the gas is slowed down when it contacts the catalyst 600 and the residence time of gas- catalyst contact is increased and the area of gas exposure at the membrane 550 is maximized.
- Figure 8 is a photograph (original magnification 100X) of a body of flexible graphite corresponding to a portion of the sketch of Figure 5.
- the articles of Figures 1 and 5 and the material shown in the photograph (100X) of Figure 8 can be shown to have increased thermal and electrical conductivity in the direction transverse to opposed parallel, planar surfaces 30, 40 as compared to the thermal and electrical conductivity in the direction transverse to surfaces 130, 140 of the material of Figure 4 in which particles of expanded natural graphite unaligned with the opposed planar surfaces are not optically detectable.
- transverse gas permeability of channeled flexible graphite sheet samples was measured, using a Gurley Model 4118 for Gas Permeability Measurement.
- Samples of channeled flexible graphite sheet in accordance with the present invention were placed at the bottom opening (3/8 in. diam.) of a vertical cylinder (3 inch diameter cross-section).
- the cylinder was filled with 300 cc of air and a weighted piston (5 oz.) was set in place at the top of the cylinder.
- the rate of gas flow through the channeled samples was measured as a function of the time of descent of the piston and the results are shown in the table below.
- the present invention for a flexible graphite sheet having a thickness of .003 inch to .015 inch adjacent the channels and a density of 0.5 to 1.5 grams per cubic centimeter, the preferred channel density is from 1000 to 3000 channels per square inch and the preferred channel size is a channel in which the ratio of the area of larger channel opening to the smaller is from 50:1 to 150:1.
- the flexible graphite sheet can, at times, be advantageously treated with resin and the absorbed resin, after curing, enhances the moisture resistance and handling strength, i.e. stiffness of the flexible graphite sheet.
- Suitable resin content is preferably 20 to 30% by weight, suitably up 60% by weight.
- the article of the present invention can be used as electrical and thermal coupling elements for integrated circuits in computer applications, as conformal electrical contact pads and as electrically energized grids in de-icing equipment.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Electrochemistry (AREA)
- Manufacturing & Machinery (AREA)
- Sustainable Energy (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Fuel Cell (AREA)
- Carbon And Carbon Compounds (AREA)
- Inert Electrodes (AREA)
Abstract
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US2000/009508 WO2001078179A1 (fr) | 2000-04-10 | 2000-04-10 | Article souple en graphite et electrode a cellule electrochimique presentant une conductivite electrique et thermique accrue |
Publications (2)
Publication Number | Publication Date |
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EP1273063A1 true EP1273063A1 (fr) | 2003-01-08 |
EP1273063A4 EP1273063A4 (fr) | 2009-04-01 |
Family
ID=21741248
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP00923203A Withdrawn EP1273063A4 (fr) | 2000-04-10 | 2000-04-10 | Article souple en graphite et electrode a cellule electrochimique presentant une conductivite electrique et thermique accrue |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP1273063A4 (fr) |
CN (1) | CN1326278C (fr) |
AU (2) | AU4336900A (fr) |
BR (1) | BR0017202B1 (fr) |
CA (1) | CA2405303C (fr) |
MX (1) | MXPA02009995A (fr) |
WO (1) | WO2001078179A1 (fr) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ATE543231T1 (de) * | 2000-04-14 | 2012-02-15 | Graftech Inc | Graphitteile für den einsatz als elektrode einer elektrochemischen brennstoffzelle |
DE102004035309A1 (de) * | 2004-07-21 | 2006-02-16 | Pemeas Gmbh | Membran-Elektrodeneinheiten und Brennstoffzellen mit erhöhter Lebensdauer |
US7687090B2 (en) | 2004-11-30 | 2010-03-30 | Corning Incorporated | Fuel cell device assembly and frame |
KR100658756B1 (ko) | 2006-02-16 | 2006-12-15 | 삼성에스디아이 주식회사 | 연료 혼합형 연료 전지용 막-전극 어셈블리 및 이를포함하는 연료 혼합형 연료 전지 시스템 |
KR100709222B1 (ko) | 2006-02-20 | 2007-04-18 | 삼성에스디아이 주식회사 | 연료 혼합형 연료 전지용 스택 및 이를 포함하는 연료혼합형 연료 전지 시스템 |
US7767357B2 (en) | 2007-07-20 | 2010-08-03 | Ngk Insulators, Ltd. | Reactor |
CN102044677A (zh) * | 2009-10-15 | 2011-05-04 | 鼎佳能源股份有限公司 | 燃料电池的导电双极板 |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4752518A (en) * | 1986-07-31 | 1988-06-21 | Polycarbon, Inc. | Flexible surface deformation-resistant graphite foil |
WO2000003445A2 (fr) * | 1998-07-09 | 2000-01-20 | Ucar Carbon Technology Corporation | Electrode faite d'un composite souple a base de graphite |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5707755A (en) * | 1996-12-09 | 1998-01-13 | General Motors Corporation | PEM/SPE fuel cell |
US5981098A (en) * | 1997-08-28 | 1999-11-09 | Plug Power, L.L.C. | Fluid flow plate for decreased density of fuel cell assembly |
-
2000
- 2000-04-10 EP EP00923203A patent/EP1273063A4/fr not_active Withdrawn
- 2000-04-10 MX MXPA02009995A patent/MXPA02009995A/es active IP Right Grant
- 2000-04-10 AU AU4336900A patent/AU4336900A/xx active Pending
- 2000-04-10 CN CNB008196400A patent/CN1326278C/zh not_active Expired - Fee Related
- 2000-04-10 WO PCT/US2000/009508 patent/WO2001078179A1/fr active IP Right Grant
- 2000-04-10 AU AU2000243369A patent/AU2000243369B2/en not_active Ceased
- 2000-04-10 BR BRPI0017202-2A patent/BR0017202B1/pt not_active IP Right Cessation
- 2000-04-10 CA CA002405303A patent/CA2405303C/fr not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4752518A (en) * | 1986-07-31 | 1988-06-21 | Polycarbon, Inc. | Flexible surface deformation-resistant graphite foil |
WO2000003445A2 (fr) * | 1998-07-09 | 2000-01-20 | Ucar Carbon Technology Corporation | Electrode faite d'un composite souple a base de graphite |
Non-Patent Citations (1)
Title |
---|
See also references of WO0178179A1 * |
Also Published As
Publication number | Publication date |
---|---|
EP1273063A4 (fr) | 2009-04-01 |
AU2000243369B2 (en) | 2005-11-24 |
CN1326278C (zh) | 2007-07-11 |
BR0017202A (pt) | 2004-01-06 |
BR0017202B1 (pt) | 2010-11-03 |
CA2405303A1 (fr) | 2001-10-18 |
WO2001078179A1 (fr) | 2001-10-18 |
CA2405303C (fr) | 2009-02-03 |
CN1454399A (zh) | 2003-11-05 |
MXPA02009995A (es) | 2003-02-12 |
AU4336900A (en) | 2001-10-23 |
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