Classifications

• • 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]
• • 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
  • H01M4/925—Metals of platinum group supported on carriers, e.g. powder carriers
  • H01M4/926—Metals of platinum group supported on carriers, e.g. powder carriers on carbon or graphite
• • 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
• • 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
• • 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 a fuel cell, and more particularly to a fuel cell capable of improving durability.
• a fuel cell includes a membrane electrode assembly (hereinafter referred to as “MEA (Membrane)” including an electrolyte layer (hereinafter referred to as “electrolyte membrane”) and electrodes (anode and cathode) disposed on both sides of the electrolyte membrane. Electrode Assembly) ”) The electrical energy generated by the electrochemical reaction in) is taken out through separators arranged on both sides of this ME A.
• solid polymer fuel cells hereinafter referred to as “PEFC (Polymer Electrolyte Fuel Cell) used in home-use cogeneration systems and automobiles are used in the low-temperature region. Is possible.
• the PEFC unit cell includes an electrolyte membrane, an anode and force sword with at least a catalyst layer, and a separator.
• the PEFC anode electrode is supplied with a reaction gas containing hydrogen
• the cathode electrode is supplied with a reaction gas containing oxygen.
• These reaction gases and a catalyst contained in the catalyst layer for example, P t Etc.
• electrochemical reactions occur at the three-phase interface formed by the electrolyte components. This electrochemical reaction makes it possible to obtain an electromotive force of about 0.7 V, for example, with a PEFC unit cell.
• the catalyst layer stack surface, the electrolyte membrane stack surface, and the diffusion layer stack surface are usually different in shape and size, so a space (gap) is formed at the end of the electrolyte membrane.
• Cheap water is generated by an electrochemical reaction, and hydrogen peroxide is generated as a side reaction. If this hydrogen peroxide is present in the space formed at the end of the electrolyte membrane (hereinafter sometimes referred to as the “space between the electrolyte membrane and the diffusion layer”), the electrolyte membrane may deteriorate. .
• the technique disclosed in Japanese Patent Application Laid-Open No. 2000-310 9 6 2 3 is characterized in that a molecule having excellent oxidation resistance is contained in the catalyst layer.
• an object of the present invention is to provide a fuel cell capable of improving durability. Disclosure of the invention
• an aspect of the present invention includes an electrolyte membrane, a catalyst layer laminated on both sides of the electrolyte membrane, and a diffusion layer laminated on the outside of the catalyst layer, and the lamination surface of the catalyst layer is an electrolyte.
• the surface of the electrolyte membrane that should be in contact with the catalyst layer is smaller than the membrane lamination surface, the diffusion layer lamination surface is larger than the catalyst layer lamination surface, and smaller than the electrolyte membrane lamination surface.
• the surface A 2 has a hydrogen peroxide decomposition performance
• a fuel cell comprising a single element and / or a compound containing the metal element.
• lamination surface means a plane whose normal direction is the lamination direction of the catalyst layers.
• the surface A 2 of the electrolyte membrane is provided with a simple substance of a metal element capable of decomposing hydrogen peroxide, and Z or a compound containing the metal element” means that the surface A 2 has hydrogen peroxide.
• metal elements capable of decomposing hydrogen peroxide include Mn, Fe, Pt, Pd, Ni, Cr, Cu, Ce, Sc, Rb, Co , I r, A g, A u, R h, T i, Z r, A l, H f, Ta, N b, O s, etc.
• specific examples of the compound include oxides containing the above metal elements, etc. Can do.
• the adhesive material layer may be disposed on the surface A 2.
• the adhesive material layer includes a simple substance of a metal element having hydrogen peroxide decomposition performance, and Z or a compound containing the metal element. May be provided.
• the catalyst layer may be provided with a single metal element having hydrogen peroxide decomposing ability and / or a compound containing the metal element.
• water accumulates in the space formed at the end of the electrolyte membrane, and even if hydrogen peroxide remains in this water, it is peroxidized on the surface A 2 of the electrolyte membrane to be contacted with water. Since there is a simple metal element having hydrogen decomposing performance and a compound containing the metal element or the metal element (hereinafter, simply referred to as “hydrogen peroxide decomposing substance”), the end of the electrolyte membrane is provided. It becomes possible to decompose the hydrogen peroxide provided in the space formed in this. Therefore, according to the present invention, it is possible to provide a fuel cell capable of improving durability.
• the adhesive material layer is disposed on the surface A 2. Then, the space formed at the end of the electrolyte membrane can be closed with the adhesive material layer. Therefore, by reducing the amount of water collected at the end of the electrolyte membrane, it becomes possible to reduce the amount of hydrogen peroxide remaining in the space, and temporarily accumulates water in the space, and this water contains hydrogen peroxide. Even if it is, hydrogen peroxide can be decomposed by the hydrogen peroxide decomposing substance provided on the surface A 2 of the electrolyte membrane.
• the adhesive material layer is provided with a hydrogen peroxide decomposition substance
• the hydrogen peroxide remaining at the end of the electrolyte membrane is converted into the peroxide material provided in the adhesive material layer. It can be decomposed by a hydrogenolytic substance. Therefore, with such a configuration, it is possible to provide a fuel cell capable of effectively improving durability.
• the catalyst layer is provided with a hydrogen peroxide decomposition substance, hydrogen peroxide can be decomposed more effectively. Therefore, with this configuration, the durability of the fuel cell can be further improved.
• FIG. 1 is a cross-sectional view schematically showing a fuel cell of the present invention according to a first embodiment and an electrolyte membrane of the fuel cell.
• FIG. 2 schematically shows an example of a fuel cell according to the second embodiment of the present invention. It is sectional drawing shown.
• FIG. 3 is a cross-sectional view schematically showing an embodiment of the fuel cell of the present invention according to the third embodiment.
• FIG. 4 is a cross-sectional view schematically showing a conventional fuel cell.
• 1 is an electrolyte membrane
• 2 a is an anode catalyst layer
• 2 b is a force sword catalyst layer
• 3 a is an anode diffusion layer
• 3 b is a force sword diffusion layer
• 10 is a cerium oxide-containing layer ( Hydrogen peroxide-decomposing substance-containing layer)
• 20 and 21 are adhesive material layers
• 100, 20 and 30 are fuel cells.
• PEFC the electrochemical reaction occurs where protons and electrons are generated from hydrogen, while in the cathode, oxygen reacts with electrons that have traveled through the external circuit and protons that have passed through the electrolyte membrane. As a result, water is generated.
• side reactions occur in addition to these main reactions, and hydrogen peroxide is generated by these side reactions.
• iron ions etc. are present in PEFC, OH radicals etc. are generated from hydrogen peroxide, and the electrolyte components contained in the electrolyte membrane etc. are oxidized and deteriorated by these OH radicals. Hydrogen peroxide generated in the PEFC can move with water generated by the electrochemical reaction in the PEFC by diffusion, etc.
• the laminated surface of the electrolyte membrane in PEFC is usually larger than the laminated surface of the catalyst layer.
• the present invention has been made to solve such a problem, and the gist of the present invention is that the surface of the electrolyte membrane does not contact the catalyst layer and forms a space between the electrolyte membrane and the diffusion layer. It is an object of the present invention to provide a fuel cell capable of improving durability by providing a hydrogen peroxide-decomposing substance.
• FIG. 4 is a cross-sectional view schematically showing a conventional fuel cell, and the vertical direction of the figure is the stacking direction of the catalyst layers.
• a conventional fuel cell 90 includes an electrolyte membrane 9 1, and an anode catalyst layer 9 2 a and a cathode catalyst layer 9 2 b disposed on both sides of the electrolyte membrane 9 1.
• MEA 95, the anode diffusion layer 3a and the force sword diffusion layer 3b disposed on both sides of the MEA 95, and the outside of the anode diffusion layer 3a and the force source diffusion layer 3b.
• Separators 6 and 6 are provided.
• anode catalyst layer 9 2 a and the force sword catalyst layer 9 2 b for example, carbon particles carrying platinum functioning as a catalyst for electrochemical reaction are supported.
• the anode diffusion layer 3 a and the force sword diffusion layer 3 b are made of carbon paper made of carbon fiber, for example. 6, the fastening pressure is applied to the electrolyte membrane 9 1 side.
• the separators 6 and 6 arranged outside the MEA 95 are provided with reaction gas supply paths 7 a, 7 a,..., And 7 b on the anode diffusion layer 3 a and force sword diffusion layer 3 b sides, respectively. , 7 b, ... are formed, and the reaction gas supply path 7 a, 7 a, ...
• hydrogen a hydrogen-containing substance
• air oxygen-containing substances
• the power sword of a fuel cell is a potential environment of about 0.4 to 1.0 V, and when oxygen is reduced on platinum-supported carbon in such an environment, hydrogen peroxide is generated. OH radicals are generated due to hydrogen oxide.
• the force sword diffusion layer 3 b is made of carbon fiber, so that hydrogen peroxide is generated even when oxygen is reduced on the carbon fiber, and OH caused by hydrogen peroxide. Radicals etc. are generated.
• the electrolyte membrane 9 1 Spaces 50, 50,... are formed at the ends, and when the fuel cell 90 0 is operated, the generated water tends to accumulate in the spaces 50, 50,. It tends to stay in the space 50, 50,. Therefore, the end portion of the electrolyte membrane 91 is easily degraded and damaged by the OH radical or the like. If the electrolyte membrane 91 is broken, the voltage of the fuel cell is lowered, and the power generation performance is lowered. Therefore, it is desirable to suppress the deterioration of the electrolyte membrane and improve the durability of the fuel cell by suppressing the production of hydrogen peroxide that contributes to such damage.
• FIG. 1 is a cross-sectional view schematically showing an example of a fuel cell according to the first embodiment of the present invention and an electrolyte membrane of the fuel cell, and the vertical direction of the figure is the stacking direction of the catalyst layers. is there.
• FIG. 1 (A) is a cross-sectional view schematically showing an embodiment of the fuel cell of the present invention according to the first embodiment
• FIG. 1 (B) is an electrolyte shown in FIG. 1 (A).
• It is sectional drawing which extracts and shows only a film
• components and parts that have the same configuration as the conventional fuel cell shown in FIG. 4 are denoted by the same reference numerals as those used in FIG. 4, and description thereof is omitted as appropriate. .
• the anode catalyst layer and the force sword catalyst layer may be simply referred to as “catalyst layer”.
• the fuel cell 100 is MEA 5 having an electrolyte membrane 1 and an anode catalyst layer 2 a and a cathode catalyst layer 2 b disposed on both sides of the electrolyte membrane 1; a node diffusion layer 3 a and a cathode disposed on both sides of the MEA 5
• a diffusion layer 3 b and separators 6 and 6 disposed outside the anode diffusion layer 3 a and the force sword diffusion layer 3 b are provided.
• the anode catalyst layer 2a and the force sword catalyst layer 2b are provided with, for example, a hydrogen peroxide decomposition substance (hereinafter sometimes referred to as “cerium oxide”) together with a platinum supporting force of one bon.
• cerium oxide hydrogen peroxide decomposition substance
• the anode diffusion layer 3a and the cathode diffusion layer 3b are made of, for example, carbon paper made of carbon fiber. Then, the cerium oxide-containing layers 10, 10,... Are disposed on the surface of the electrolyte film 1 that constitutes the spaces 50, 50,. A hydrogen oxide cracking material is provided.
• the spaces 50, 50,... are formed at the end portion of the electrolyte membrane 1, when the fuel cell 100 is operated, the generated water easily collects in the space, and at the same time, peroxidation occurs. Hydrogen also tends to stay.
• the cerium oxide-containing layer 10, 10,... On the surface of the electrolyte membrane 1 constituting the spaces 50, 50,. Is provided. Therefore, according to the fuel cell 100, it becomes possible to decompose hydrogen peroxide that may exist in the spaces 50, 50,..., And as a result, damage to the end of the electrolyte membrane 1 can be suppressed. It becomes possible.
• the catalyst layers 2 a and 2 b according to the first embodiment include Contains cerium oxide. Therefore, according to the fuel cell 100, hydrogen peroxide existing in parts other than the spaces 50, 50,..., Such as the anode catalyst layer 2a and the force sword catalyst layer 2b, can be decomposed. It becomes possible. Therefore, by adopting such a configuration, it becomes possible to prevent the oxidative deterioration of the fuel cell and to provide a fuel cell capable of improving the durability.
• FIG. 1 (B) is an enlarged view showing only the electrolyte membrane 1 provided in the fuel cell 100 shown in FIG. 1 (A).
• the fuel cell 100 includes a catalyst layer having a smaller stacking surface than the electrolyte membrane, similarly to the conventional fuel cell 90.
• the surface of the electrolyte membrane 1 is an electrolyte that forms a space between the surface A 1 that should be in contact with the catalyst layers 2 a and 2 b and no contact with the catalyst layer, and between the electrolyte membrane and the diffusion layer. It can be divided into membrane surfaces A 2 and A 2 (see Fig. 1 (B)).
• FIG. 1 (B) is an enlarged view showing only the electrolyte membrane 1 provided in the fuel cell 100 shown in FIG. 1 (A).
• the fuel cell 100 includes a catalyst layer having a smaller stacking surface than the electrolyte membrane, similarly to the conventional fuel cell 90.
• the surface of the electrolyte membrane 1 is an electrolyte that forms a space between the surface A 1 that
• FIG. 2 is a cross-sectional view schematically showing an embodiment of the fuel cell of the present invention according to the second embodiment, and the vertical direction of the figure is the stacking direction of the catalyst layers.
• FIG. 2 the same configuration as that of the fuel cell according to the first embodiment shown in FIG. 1 is adopted.
• Constituent members and parts are denoted by the same reference numerals as those used in FIG. 1, and description thereof will be omitted as appropriate.
• the fuel cell 200 includes an electrolyte membrane 1 and an anode catalyst layer 2 a and a cathode catalyst layer disposed on both sides of the electrolyte membrane 1. 2b, an anode diffusion layer 3a and a force sword diffusion layer 3b disposed on both sides of the MEA 5, and the anode diffusion layer 3a and the force sword diffusion layer 3b. Separators 6 and 6 are provided on the outside. Further, the surface A 2, A 2,... Of the electrolyte membrane 1 constituting the spaces 50, 50,...
• conductive materials such as by-products with carbon filler (Byron is a registered trademark of Toyobo Co., Ltd., the same shall apply hereinafter) are provided in the spaces 50, 50,. Are provided with adhesive material layers 20, 20,.
• the adhesive material layers 20 0, 20 are formed in the spaces 50 0, 50,... Formed at the ends of the electrolyte membrane 1.
• the gaps in the spaces 50, 50, ... according to the second embodiment are smaller than the gaps in the spaces 50, 50, ... according to the first embodiment, . Therefore, according to the fuel cell 200 according to the second embodiment, the generated water hardly accumulates at the end of the electrolyte membrane 1 and hydrogen peroxide does not easily stay at the end. It becomes possible to easily suppress the oxidative deterioration of the part. In addition, even if the generated water collects in a slight gap between the spaces 50, 50,. On the surface A 2, A 2, etc.
• FIG. 3 is a cross-sectional view schematically showing an example of the fuel cell according to the third embodiment of the present invention.
• the same components as those of the fuel cell according to the second embodiment shown in FIG. 2 are denoted by the same reference numerals as those used in FIG. Is omitted as appropriate.
• the fuel cell 300 includes an electrolyte membrane 1 and an anode catalyst layer 2 a and a cathode catalyst layer 2 b disposed on both sides of the electrolyte membrane 1.
• MEA 5 provided, the anode diffusion layer 3 a and the force sword diffusion layer 3 b disposed on both sides of the MEA 5, and the outside of the anode diffusion layer 3 a and the force sword diffusion layer 3 b Separators 6 and 6 are provided.
• a 2 A 2 On the surface A 2, A 2,... Of the electrolyte membrane 1 constituting the spaces 50, 50,... Formed at the end of the electrolyte membrane 1, the adhesive material layers 21, 21, This adhesive material layer 2 1, 2 1,...
• the space 50, 50,... Formed at the end portion of the electrolyte membrane 1 is coated with cerium oxide which is a hydrogen peroxide decomposing substance. Since the adhesive material layers 2 1, 2 1,... That are included are disposed, hydrogen peroxide that may exist in the spaces 50, 50,... Is transferred to the adhesive material layers 2 1, 2 1,. It can be decomposed by the hydrogen peroxide decomposing substances (or ions eluted from the hydrogen peroxide decomposing substances). Therefore, with this configuration, it is possible to effectively improve the durability of the fuel cell 300.
• the arrangement form of the adhesive material layer is particularly limited as long as it is arranged so as to contact the surface A 2, A 2,. It is not something. However, from the viewpoint of effectively improving the durability of the electrolyte membrane and the like by reducing the gap in which the generated water and hydrogen peroxide can be retained as small as possible, the spaces 50, 50,. It is preferable to dispose the adhesive material layer in a form that can be almost completely closed.
• the glass transition temperature T 1 of the adhesive material layer is not particularly limited.
• T2 when the glass transition temperature of the electrolyte membrane is T2, T 1 ⁇ T 2
• the fuel cell can be integrated with the ME cell and the diffusion layer by thermocompression bonding. Can It becomes possible, and it becomes possible to manufacture a fuel cell easily.
• the method of disposing the adhesive material layer on the surface A2, A2, ... of the electrolyte membrane is not particularly limited. From the viewpoint of enabling easy and reliable disposition, it is preferable to dispose the adhesive material using a syringe or the like. If the adhesive material is placed using a syringe, set the needle hole diameter of the syringe! : When the elastic modulus of the diffusion layer is ⁇ and the thickness of the catalyst layer is d, It is preferable that If a syringe having a needle hole with such a diameter is used, an adhesive material in an amount capable of almost completely closing the spaces 50, 50,.
• the catalyst layer according to the present invention is not limited to this form, and the catalyst does not contain the hydrogen peroxide decomposing substance. Even a fuel cell with a layer is acceptable. However, from the viewpoint of a fuel cell capable of effectively decomposing hydrogen peroxide produced as a by-product during the operation of the fuel cell, a fuel cell having a catalyst layer containing a hydrogen peroxide decomposing substance may be used. preferable.
• cerium oxide has been provided as a hydrogen peroxide decomposition substance.
• the hydroperoxide decomposition material that can be provided in the fuel cell of the present invention is not limited to cerium oxide.
• Specific examples of hydrogen peroxide decomposing substances that can be provided in the fuel cell of the present invention include Mn, Fe, Pt, Pd, Ni, Cr, Cu, Ce, Sc, Rb, C, Ir, Ag, Au, Rh, Ti, Zr, Al, Hf, Ta, Nb, Os, etc. and / or compounds containing these metal elements Can do.
• the fuel cell including the separator in the form in which the reaction gas supply path is formed on the ME A side is described.
• the separator that can be provided in the fuel cell according to the present invention is limited to this form.
• a flat type separator in which no reaction gas supply path is formed on the MEA side may be used.
• the layers to be brought into contact with the separator are formed by a plating method or a foaming method.
• the fuel cell may be formed of a porous material such as stainless steel, foamed metal such as titanium or nickel, or sintered metal, and the reaction gas is supplied to the layer.
• the fuel cell according to the present invention is suitable for use as a power source of an electric vehicle, for example.

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• Chemical & Material Sciences (AREA)
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• Chemical Kinetics & Catalysis (AREA)
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• Life Sciences & Earth Sciences (AREA)
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• Inert Electrodes (AREA)

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• 2005
  • 2005-04-06 JP JP2005109734A patent/JP2006294293A/ja active Pending
• 2006
  • 2006-04-06 CN CNA200680020043XA patent/CN101203972A/zh active Pending
  • 2006-04-06 EP EP06731721A patent/EP1873853A4/en not_active Withdrawn
  • 2006-04-06 CA CA002604117A patent/CA2604117A1/en not_active Abandoned
  • 2006-04-06 WO PCT/JP2006/307785 patent/WO2006109837A1/ja not_active Ceased
  • 2006-04-06 US US11/918,069 patent/US20090023028A1/en not_active Abandoned

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