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
• • 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
• • 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
  • H01M8/0232—Metals or alloys
• • 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
  • H01M4/8647—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites
  • H01M4/8657—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites layered
• • 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
  • H01M4/90—Selection of catalytic material
  • H01M4/92—Metals of platinum group
• • 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
  • H01M8/0223—Composites
  • H01M8/0228—Composites in the form of layered or coated products
• • 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
  • H01M8/0241—Composites
  • H01M8/0245—Composites in the form of layered or coated products
• • 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
  • H01M8/0263—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant having meandering or serpentine paths
• • 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
  • H01M8/1009—Fuel cells with solid electrolytes with one of the reactants being liquid, solid or liquid-charged
• • 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
  • H01M8/22—Fuel cells in which the fuel is based on materials comprising carbon or oxygen or hydrogen and other elements; Fuel cells in which the fuel is based on materials comprising only elements other than carbon, oxygen or hydrogen
• • 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 fuel cells, and more particularly, to a fuel cell which can enhance an electricity generating performance.
• the fuel cell is an energy transformation device for direct transformation of a chemical energy of a fuel into an electrical energy by means of chemical reaction. Different from a general battery, the fuel cell can generate electricity continuously as far as fuel is fed without recharging. Recently, interest is focused on the fuel cell owing to the high energy efficiency, and the environment friendly nature.
• the fuel cell is provided with two electrodes, i.e., an anode and a cathode arranged on opposite sides of electrolyte.
• anode side separator on an outer side of the anode having a fuel passage and supporting the anode
• a cathode side separator on an outer side of the cathode having an air passage and supporting the cathode.
• An electro-chemical reaction of the hydrogen, the fuel takes place at the anode
• an electro-chemical reaction of the oxygen, an oxidizer takes place at the cathode
• electric energy is generated owing to immigration of electrons taken place in this time.
• the fuel cell may use a variety of fuels, such as LN LPG, methanol, gasoline, and the like.
• the fuel is refined as hydrogen by passing through a desulfurization process, a reforming reaction, and a hydrogen refining process at a fuel reformer, and used in a form of gas.
• a fuel of a water solution state for an example, a solid state BH 4 ⁇ is dissolved into a water solution state, is used as fuel (Boro Hydride Fuel Cell).
• the Boro Hydride Fuel Cell (BFC) can dispense with the fuel reformer as fuel of a water solution state is fed to the anode directly, and the reforming reaction takes place at the anode without the fuel reformer, enabling to simplify a fuel cell system.
• FIG. 1 fuel is fed from a fuel tank 5 to a fuel cell 1 by a fuel pump 3, and air is fed to the fuel cell 1 by an air pump 7.
• the fuel cell 1 is a unit cell or a stack of the unit cells. An example of a related art fuel cell will be described with reference to FIGS.
• FIGS. 2 to 4 illustrates a unit fuel cell. There are an anode 30 and a cathode 20 at opposite sides of electrolyte 10.
• separators 40 and 50 at outer sides of the anode 30 and the cathode 20, respectively.
• the anode 30 and the cathode 20 are porous and in general include Pt catalyst.
• the separators 40 and 50 support the anode 30 and the cathode 20 respectively, and have passages 46, and 56 formed in general between barriers 44, and 54. There can be a variety of passage forms.
• the separators 40, and 50 serve to separate individual unit cells when unit cells are stacked. In the meantime, there can be separate electricity collecting plates at outer sides of the separators 40, and 50, respectively.
• the electrolyte is an ion exchange membrane of a polymer material.
• a typical commercially available electrolyte membrane is National membrane of Du Pont, and serves as a transfer body of hydrogen ions, and, at the same time with this, prevents the oxygen from coming into contact with hydrogen.
• the anode 30 and the cathode 20 are supporting bodies having catalyst attached thereto of, in general, porous carbon resin or carbon cloth.
• the separators 40, and 50 are formed of, in general, dense carbon material, or Ni/SUS material. The action of the fuel cell will be described. The fuel and air fed to the fuel cell flow through the anode 30 and the cathode 20, and make the following chemical reaction.
• Japanese Laid Open Patent No. H10-228913 suggests partial gold plating of electrodes and separators, to reduce contact resistances between the electrodes and the separators, to improve the performance of the fuel cell.
• the separators are formed of metal, and the separators are formed of stainless steel for prevention of corrosion.
• An object of the present invention designed to solve above problems, is to provide a fuel cell which can improve an electric generating capacity and performance without increasing a size of the fuel cell.
• the object of the present invention can be achieved by providing a fuel cell including electrolyte, an anode and a cathode at opposite sides of the electrolyte, an anode side separator and a cathode side separator at outer sides of the anode and the cathode respectively, and a medium layer between the cathode and the cathode side separator for prevention of corrosion of the cathode side separator.
• a fuel cell including electrolyte, an anode and a cathode at opposite sides of the electrolyte, an anode side separator at an outer side of the anode, a cathode side separator at an outer side of the cathode, a porous supporting member between the cathode and the cathode side separator for supporting the cathode, and a supporting member medium layer between the cathode and the porous supporting member for prevention of corrosion of the porous supporting member.
• a fuel cell including electrolyte, an anode and a cathode at opposite sides of the electrolyte, an anode side separator and a cathode side separator at outer sides of the anode and the cathode respectively, and a medium layer between the anode and the anode side separator for prevention of corrosion of the anode side separator.
• FIG. 1 illustrates a block diagram of a related art fuel cell system
• FIG. 2 illustrates a disassembled perspective view of a related art fuel cell, schematically
• FIG. 3 illustrates a plan view of one example of the cathode side separator in
• FIG. 2 schematically;
• FIG. 4 illustrates a section of FIG. 2;
• FIG. 5 illustrates a circuitry expression of the fuel cell in FIG. 2;
• FIG. 6 illustrates a graph of a voltage drop in the fuel cell;
• FIG. 7 illustrates a section of a fuel cell in accordance with a preferred embodiment of the present invention, schematically;
• FIGS. 8 and 9 illustrate graphs each showing comparison of electric generating capacity of the fuel cells of the present invention and the related art;
• FIG. 10 illustrates a section of a fuel cell in accordance with another preferred embodiment of the present invention, schematically.
• an anode 30, a cathode 20, an anode side separator 50, and a cathode side separator 40 has one side in contact with the anode 30, and the other side in contact with the cathode 20 at the same time in a stack type fuel cell having a plurality of unit cells stacked therein, for the sake of description, words of an anode side separator 50, and a cathode side separator 50 will be used in the following description. From study of the inventors, it is found out that prevention of corrosion of the separators, particularly, the cathode side separator 40 is very important for improving performance of the fuel cell. Because, as shown in FIG. 5, when the fuel cell generates electricity, ions move from the anode - the electrolyte — » the cathode, and electrons
• Japanese Laid Open Patent No. HI 0-228913 suggests partial gold plating at contact surfaces of electrodes and separators, to reduce contact resistances between the electrodes and the separators simply, and to use stainless steel as a material of the separators for prevention of corrosion.
• the medium layer 300 between the cathode side separator 40 and the cathode 40 for prevention of corrosion of the cathode side separator 40.
• the medium layer 300 may be provided separately, it is preferable that the medium layer 300 is a coated layer of a material selected from materials having ionization tendencies similar to the cathode 20. Because it is found out from the study of the inventors that a principal cause of the corrosion at the cathode side separator 40 is a voltage difference coming from a difference of the ionization tendencies of the cathode 20 and the cathode side separator 40.
• the coated layer 300 on the cathode side separator 40 is at least on a contact surface 302 to the cathode 20, and a bottom surface 304 of the passage, and preferably on a wall surface 306 of the passage.
• the coated layer 300 may be formed of Pt, gold, copper, nickel, and the like having ionization tendency the same or similar to Pt, and it is preferable that the coated layer 300 is formed of gold, taking production cost, and process, and the like into account.
• the corrosion may take place at the anode side separator 50.
• a medium layer (not shown), for an example, the coated layer, is formed on the anode side separator 50 for prevention of corrosion of the anode side separator 50.
• the coated layer is formed of a material selected from materials that show no voltage differences from the anode 30. Referring to FIG. 8, as a result of experiment of the inventors, in a case of a fuel cell with the cathode side separator 40 including Pt, it is verified that the fuel cell with a gold coated layer can improve approx. 50% of electric generating performance compared to the related art fuel cell without the coated layer if other conditions are the same.
• FIG. 10 there may be a porous supporting member 100, for an example, a mesh member, between the cathode 20 and the cathode side separator 40.
• the supporting member 100 is also corroded, and it is preferable that such corrosion is prevented. That is, gold plating on the supporting member 100 reduces the inner resistance, and shows performance improvement. Of course, it is more effective if the cathode side separator 40 is coated with gold.
• anode supporting member 80 between the anode 30, and the anode side separator 50, and the same principle is applicable to the anode supporting member 80.
• the principle of above embodiments is not limited to a fuel cell of the BFC type, but is applicable to other fuel cells, too.
• Industrial Applicability The effective prevention of corrosion at the cathode side separator and/or the anode side separator permits to reduce an inner resistance of the fuel cell, to improve electric generating performance, and capacity, at the end.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Fuel Cell (AREA)

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Citations (9)

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• 2004
  • 2004-04-19 CN CNA2004800427764A patent/CN1938888A/zh active Pending
  • 2004-04-19 WO PCT/KR2004/000892 patent/WO2005101559A1/en active Application Filing
  • 2004-04-19 EP EP04728294A patent/EP1738429A1/de not_active Withdrawn

Patent Citations (9)

Non-Patent Citations (2)

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