Classifications

• • 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
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
  • C25B9/60—Constructional parts of cells
  • C25B9/65—Means for supplying current; Electrode connections; Electric inter-cell connections
• • 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
  • H01M8/0204—Non-porous and characterised by the material
  • H01M8/0221—Organic resins; Organic polymers
• • 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
  • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• • 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 bipolar plates, especially for use in electrochemical processes.
• the present invention also relates to methods for providing such bipolar plates
• Bipolar plates are well known for use in electrochemical processes, e.g. full cells.
• Reactors of electrochemical processes may comprise an anode and a cathode chamber being separated from each other by means of a liquid and gas tight barrier. Meanwhile, an electrically conductive electrode is provided in this anode and cathode chamber.
• the bipolar plate may act as a liquid and gas barrier between anode and cathode chamber.
• the electrodes from the anode side and the cathode side are to be in electrical contact with each other.
• EP229473B1 describes such a bipolar plate comprising a polymer wall and a first and a second electrode, each at one side of the polymer wall.
• the electrodes are provided using an undulated, possibly perforated metal sheet or an undulated wire mesh, in the form of a woven structure.
• the electrodes are partially embedded in the polymer wall, and make electrical contact with each other in the polymer wall.
• the presence of such amount of metal sheet causes significant pressure drops necessary for evacuation of distribution of reactant gasses in the electrodes. It also causes the bipolar plate to have a relatively large weight.
• bipolar plate which is an alternative for the bipolar plates presently known in the art. It is also an object of the present invention to facilitate the embedding of the electrodes in the polymer wall. It is also an object of the present invention to provide a bipolar plate having an improved anchoring of the electrode to the polymer wall. It is also an object of the present invention to provide a bipolar plate having a more certain contact of both electrodes in the polymer wall. It is further an object of the present invention to provide a bipolar plate improving the evacuation of gasses obtained as a result of the electrochemical reactions. It is also an object of the present invention to facilitate the distribution of gasses being reactants for the electrochemical reactions over the whole surface of the electrodes.
• a bipolar plate as subject of the invention comprises a polymer wall and a first and a second electrode.
• the first electrode is positioned at a first side of the polymer wall, whereas the second electrode is positioned at the second side of the polymer wall. Both electrodes are partially embedded in the polymer wall, making electrical contact with each other in this polymer wall.
• the bipolar plate as subject of the invention is characterized in that at least one of the first or second electrodes comprises a metal wire knitted fabric, which is partially embedded in the polymer wall. Possibly both electrodes comprise metal wire knitted fabrics, which are partially embedded in the polymer wall.
• the electrodes may even consist of metal wire knitted fabric. Possibly each electrode comprises more than one layer of metal wire knitted fabric, all layers added one on top of the other.
• the layer closest to the polymer wall is partially embedded in the polymer wall. It was also found that the use of metal wire knitted fabrics, the embedding of the fabrics is facilitated and can be done in a more accurate way. It was also found that the use of a metal wire knitted fabric, who is partially embedded in the polymer wall, provides an improved anchoring of the electrode in the polymer wall. As both electrodes are partially embedded in the polymer wall and make electrical contact in the polymer wall, the improved anchoring results in a more certain electrical contact between the electrodes over time.
• bipolar plates as subject of the invention comprising electrodes consisting of possibly more than one layer of metal wire knitted fabric for each electrode
• the gasses obtained by the chemical reactions may more easily and with less pressure drop be evacuated from the electrodes.
• gasses are used as reactants, such gasses are distributed more easily and equally over the whole electrode volume, requiring less pressure to be distributed.
• liquids used during electrochemical reaction are distributed more easily and equally over the whole electrode volume.
• the bipolar plate is less heavy. The fact of comprising less metal volume may also decrease the production price of bipolar plates.
• the metal wire knitted product, used to provide a bipolar plate as subject of the invention, is not necessarily to be undulated as for the bipolar plates of the prior art. Therefor one step in production of bipolar plates may be avoided, further reducing production costs.
• Metal wire having a diameter in the range of 0.05 mm to 0.5 mm may be used to provide the metal wire knitted fabrics. More preferred, metal wires with a diameter in the range of 0.05 mm to ⁇ .3 mm, such as in the range of 0.05 mm to 0.25 mm or in the range of 0.05 mm to 0.1 mm may be used. As metal wire, metal wires out of Ni or Ni-alloy may be used. Alternatively titanium, titanium alloys, or stainless steel alloys, such as alloys of the AISI 300-series or AISI 400-series may be used, e.g. AISI 302, AISI 304, AISI 310, AISI 316, AISI 316L, AISI 347, AISI 430, AISI 434 or AISI 444.
• AISI 302 AISI 304, AISI 310, AISI 316, AISI 316L, AISI 347, AISI 430, AISI
• the polymer wall preferably is a polymer sheet.
• the thickness of the polymer wall is preferably more than 0.5 mm but less than 5mm. The selection of the thickness may influence the gas and liquid impermeability of the polymer wall, and may influence the diffusion coefficient of gas molecules through the polymer wall.
• the polymer material used to provide the polymer wall is preferably selected from the group consisting of fluoro-polymers such as polytetrafluorethylene, or polyolefines, such as e.g. polypropylene, polyethylene or high-density polyethylene, polyacetal or polysulfon.
• fluoro-polymers such as polytetrafluorethylene, or polyolefines, such as e.g. polypropylene, polyethylene or high-density polyethylene, polyacetal or polysulfon.
• the polymer wall is a polymer sheet, being obtained by extrusion processes. Extruded polymer sheets guarantee to a larger extent the gas- and liquid-tightness.
• the two electrodes of which at least one comprises a metal wire knitted fabric, are embedded partially in the polymer wall.
• the metal wire knitted fabrics are laminated together with the polymer wall, which is preferably a polymer sheet.
• the depth of the embedding of one of the metal wire knitted fabrics of the electrodes is chosen in such a way that both electrodes contact each other in the polymer wall, so providing electrical contact between the two electrodes.
• the thickness of the metal wire knitted fabric being more than half of the thickness of the polymer wall.
• the metal wire knitted fabric has a thickness less than 5 mm.
• I ne electrode may comprise additional elements next to tne partially embedded metal wire knitted fabric, e.g. spacing elements or catalyst carrying elements. Possibly more than one layer of metal wire knitted fabric may be used for each electrode, one layer being on top of the other, as an example to provide sufficient volume to the electrode or to provide the other elements of the electrode.
• a catalyst for use in the electrochemical reaction may be present.
• a catalyst selected from the group consisting of Rh, Ru, Pt, Pd, Ir, Ag, Ni, Cu, WC or AU or combinations thereof may be used.
• the catalyst on the first electrode may be identical or different as the catalyst on the second electrode. Possibly, the catalysts are only present at a certain zone of the electrode. As an example, the catalyst may only be present at the side of the electrode removed from the polymer wall.
• an electrode may comprise a first metal wire knitted fabric, partially embedded in the polymer wall as subject of the invention.
• a second metal wire knitted fabric functioning as spacing layer between the first metal wire knitted fabric and the catalyst carrier is present on top of the first metal wire knitted fabric.
• a third metal fiber knitted fabric being coated with a catalyst, is provided functioning as catalyst carrier.
• the bipolar plates as subject of the invention may be used in all kinds of electrochemical reactors, such as e.g. fuel cells, electrolysers or H 2 - production units.
• the electrode comprises more than one layer of metal wire knitted fabric, only some layers may be coated with a catalyst. Most preferred, the metal wire knitted fabric who is partially embedded in the polymer wall is not coated with a catalyst.
• the method provided bipolar plates in a more economic way, and in the mean time it is easy to control, as some process parameters, e.g. pressure during lamination is less critical.
• Some process parameters e.g. pressure during lamination is less critical.
• the latter is due to the elasticity the metal wire knitted fabrics possess in a direction perpendicular to its surface.
• the method of production of a bipolar plate as subject of the invention further comprises the step of coating one or both of the metal wire knitted fabrics with a catalyst.
• the method of production of a bipolar plate further comprises the step of adding different layers of metal wire knitted fabric one on top of the other before or after laminating, in order to obtain electrodes comprising more than one layer of metal wire knitted fabric.
• FIGURE 1 shows schematically a side view of a bipolar plate as subject of the invention
• FIGURE 2 shows schematically a cross section according to plane AA' of a bipolar plate as subject of the invention of FIGURE 1.
• FIGURE 3 and FIGURE 4 show schematically a cross section of alternative bipolar plates as subject of the invention. Description of the preferred embodiments of the invention.
• FIGURE 1 A side view of a bipolar plate 110 as subject of the invention is shown in FIGURE 1.
• a polymer wall 120 has two outer surfaces, and at least in one surface 121 , a metal wire knitted fabric 130 being part of an electrode is partially embedded in the polymer wall 120.
• a metal wire knitted fabric 130 being part of an electrode is partially embedded in the polymer wall 120.
• possibly another metal wire knitted fabric 140 (not shown for reason of clarity in FIGURE 1) being part of the electrode at the other side 122 is partially embedded in the polymer wall 120.
• FIGURE 2 shows a cross section of the bipolar plate 110, having two electrodes comprising metal wire knitted fabric (130 and 140), one at each side of the polymer wall 120.
• a bipolar plate 110 comprises a polymer wall 120 with a thickness 221 , e.g. 2mm.
• a metal wire knitted fabric 130 and 140 is partially embedded over a depth of slightly more than half of the thickness 221 of the polymer wall 120. It is understood that the thickness 233 and 243 of the metal wire knitted fabrics is to be substantially more than this half of the thickness 221 of the polymer wall 120, in order to provide a significant volume to the electrode which is not embedded in the polymer wall, providing void volume to the electrodes for gas evacuation of supply of reactant gas or reactant liquid.
• the metal wire knitted fabric 130 may be coated with a catalyst based on Pt and Ru.
• the metal wire knitted fabric 140 may be coated with a catalyst based on Pt and Ir.
• the metal wire knitted fabrics 130 and 140 may be a double bed knitted structure (either warp of weft knitted) using a machine gauge of 5 (5 needles per inch of needle bed). A nickel wire of diameter 250 ⁇ m may be used.
• i ne meiai wire Knitted taonc is preterably embedded in the polymer wall, being preferably a polymer sheet, by laminating the knitted fabric in the sheet.
• FIGURE 3 A cross section of an alternative bipolar plate as subject of the invention is shown in FIGURE 3.
• the bipolar plate 310 comprises a polymer wall 320, being an extruded polymer sheet of high-density polypropylene (HDPP), polysulfon, polyacetal or high-density polyethylene (HDPE).
• the thickness 321 of the polymer sheet is approximately 1mm.
• a first electrode 330 is located, comprising two layers of metal wire knitted fabric (indicated 331 and 332), the layer of metal wire knitted fabric 331 , closest to the polymer wall 320 is partially embedded in the polymer wall 320.
• the thickness of the electrode (indicated 333), being the sum of thickness of layer 331 and layer 332, is approximately
• each layer 331 and 332 has a thickness of approximately 3.5mm.
• Layer 331 is embedded in polymer wall over a depth of slightly more than 0.5mm.
• a second electrode 340 is located, comprising two layers of metal wire knitted fabric (indicated 341 and 342), the layer of metal wire knitted fabric 341 , closest to the polymer wall 320 is partially embedded in the polymer wall 320.
• the thickness of the electrode (indicated 343), being the sum of thickness of layer 341 and layer 342, is approximately 7mm, wherein each layer 341 and 342 has a thickness of approximately 3.5mm.
• Layer 341 is embedded in polymer wall over a depth of slightly more than 0.5mm.
• me metal wire Knitted ⁇ aor ⁇ cs ⁇ ⁇ , OOZ, i and 34 ' i may be a single jersey knitted structure using a machine gauge of 5 (5 needles per inch of needle bed).
• a nickel wire of diameter 250 ⁇ m may be used, providing a metal wire knitted fabric having a thickness of approximately 3.5mm, having a weight of 47.5 g/m 2 and density of 1.7%
• the layer 332 may be coated with a catalyst based on Pt and In.
• the layer 342 may be coated with a catalyst based on Pt and Ir.
• FIGURE 4 A cross section of an alternative bipolar plate as subject of the invention is shown in FIGURE 4.
• the bipolar plate 410 comprises a polymer wall 420, being an extruded polymer sheet of high-density polypropylene (HDPP), polysulfon, polyacetal or high-density polyethylene (HDPE).
• the thickness 421 of the polymer sheet is approximately 1 mm.
• a first electrode 430 is located, comprising three layers of metal wire knitted fabric (indicated 431 , 432 and 433), the layer of metal wire knitted fabric 431 , closest to the polymer wall 420 is partially embedded in the polymer wall 420.
• the thickness of the electrode (indicated 434), being the sum of thickness of layer 431 , layer 432 and layer 433, is approximately 10.5mm, wherein each layer 431 , 432 and 433 has a thickness of approximately 3.5mm.
• Layer 431 is embedded in polymer wall over a depth of slightly more than 0.5mm.
• a second electrode 440 is located, comprising three layers of metal wire knitted fabric (indicated 441 , 442 and 443), the layer of metal wire knitted fabric 441 , closest to the polymer wall 420 is partially embedded in the polymer wall 420.
• the thickness of the electrode (indicated 444), being the sum of thickness of layers 441 , 442 and 443, is approximately 10.5mm, wherein each layer
• 341 and 342 has a thickness of approximately 3.5mm.
• Layer 441 is embedded in polymer wall over a depth of slightly more than 0.5mm.
• AS ootn metal wire Knitted products 431 and 441 are embedded using a depth of slightly more than half of the thickness 421 of the polymer wall, an electrical contact between both metal wire knitted fabrics 431 and 441 , and thus between both electrodes 430 and 440 is ensured.
• the metal wire knitted fabrics 441 , 442, 443, 431 , 432 and 433, may be identical as the metal wire knitted fabric used for the embodiment as shown in FIGURE 3.
• the metal wire knitted fabrics 432 and 442 function as spacing layers between the first metal wire knitted fabrics 431 and 441 , and the third metal wire knitted fabrics 433 and 443, which are coated with a catalyst based on Pt and In for metal wire knitted fabric 433 and a catalyst based on Pt and Ir for metal wire knitted fabric 443.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Engineering & Computer Science (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Metallurgy (AREA)
• Materials Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Inert Electrodes (AREA)
• Electrodes For Compound Or Non-Metal Manufacture (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

Priority Applications (7)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (7)

Cited By (7)

Families Citing this family (9)

Citations (2)

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• 2003
  • 2003-04-29 CN CNA038263890A patent/CN1771354A/zh active Pending
  • 2003-04-29 WO PCT/EP2003/050130 patent/WO2004097073A1/en not_active Application Discontinuation
  • 2003-04-29 US US10/554,515 patent/US20060213767A1/en not_active Abandoned
  • 2003-04-29 JP JP2004571245A patent/JP2006524747A/ja active Pending
  • 2003-04-29 CA CA002520918A patent/CA2520918A1/en not_active Abandoned
  • 2003-04-29 AU AU2003238520A patent/AU2003238520A1/en not_active Abandoned
  • 2003-04-29 EP EP03732588A patent/EP1649081A1/en not_active Withdrawn

Patent Citations (2)

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