WO2008068887A1 - Pile à combustible - Google Patents

Pile à combustible Download PDF

Info

Publication number
WO2008068887A1
WO2008068887A1 PCT/JP2007/001279 JP2007001279W WO2008068887A1 WO 2008068887 A1 WO2008068887 A1 WO 2008068887A1 JP 2007001279 W JP2007001279 W JP 2007001279W WO 2008068887 A1 WO2008068887 A1 WO 2008068887A1
Authority
WO
WIPO (PCT)
Prior art keywords
fuel
electrode
catalyst layer
fuel cell
air electrode
Prior art date
Application number
PCT/JP2007/001279
Other languages
English (en)
Japanese (ja)
Inventor
Jun Momma
Asako Sato
Yuichi Yoshida
Original Assignee
Kabushiki Kaisha Toshiba
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kabushiki Kaisha Toshiba filed Critical Kabushiki Kaisha Toshiba
Priority to JP2008548160A priority Critical patent/JPWO2008068887A1/ja
Publication of WO2008068887A1 publication Critical patent/WO2008068887A1/fr

Links

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
    • 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
    • H01M8/1011—Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
    • 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 particularly to a small liquid fuel direct supply type fuel cell
  • lithium ion secondary batteries In response to the demand for such secondary batteries, for example, lithium ion secondary batteries have been developed.
  • the operation time of portable electronic devices tends to increase further, and in lithium ion secondary batteries, the improvement in energy density is almost limited from the viewpoints of materials and structures. It is becoming impossible to respond to
  • DMFC methanol is oxidatively decomposed at the fuel electrode, producing carbon dioxide, protons and electrons.
  • the air electrode water is generated by oxygen obtained from air, protons supplied from the fuel electrode through the electrolyte membrane, and electrons supplied from the fuel electrode through an external circuit. In addition, power is supplied by electrons passing through this external circuit.
  • WO2005 / 1 1 21 72 discloses a technique for constructing a small DMFC by installing an intake port directly attached to a power generation element without using a blower for air intake. .
  • a small DMFC instead of simplifying the mechanism of such a small DMFC, it is difficult to send a certain amount of methanol to the power generation element when affected by external environmental factors such as temperature. For this reason, it has become difficult to achieve stable and high output.
  • Patent Document 1 WO2005 / 1 1 21 72 publication
  • Patent Document 2 Japanese Unexamined Patent Application Publication No. 2004 _ 1 7 1 844
  • an object of the present invention is to provide a fuel cell that can supply fuel to the fuel electrode while suppressing a decrease in fuel concentration and can maintain a stable output in long-term continuous use. .
  • a fuel electrode including an anode catalyst layer and an anode gas diffusion layer provided facing one surface of the anode catalyst layer, an air electrode catalyst layer, and And an air electrode having an air electrode gas diffusion layer provided facing one surface of the air electrode catalyst layer, and an electrolyte membrane sandwiched between the fuel electrode catalyst layer and the air electrode catalyst layer.
  • a fuel cell comprising the membrane electrode assembly, wherein the porosity of the fuel electrode gas diffusion layer is smaller than the porosity of the air electrode gas diffusion layer.
  • a fuel electrode provided with a fuel electrode catalyst layer and a fuel electrode gas diffusion layer provided facing one surface of the fuel electrode catalyst layer, an air electrode catalyst layer, and A membrane comprising an air electrode comprising an air electrode gas diffusion layer provided facing one surface of the air electrode catalyst layer, and an electrolyte membrane sandwiched between the fuel electrode catalyst layer and the air electrode catalyst layer
  • a fuel cell comprising an electrode assembly, wherein the fuel electrode catalyst layer has a lower porosity than the air electrode catalyst layer is provided.
  • a fuel electrode and an air electrode catalyst layer comprising a fuel electrode catalyst layer and a fuel electrode gas diffusion layer provided facing one surface of the fuel electrode catalyst layer And an air electrode having an air electrode gas diffusion layer provided facing one surface of the air electrode catalyst layer, and an electrolyte membrane sandwiched between the fuel electrode catalyst layer and the air electrode catalyst layer.
  • a fuel cell comprising a membrane electrode assembly, wherein the porosity of the fuel electrode gas diffusion layer is smaller than the porosity of the air electrode gas diffusion layer, and the porosity of the fuel electrode catalyst layer is There is provided a fuel cell characterized by having a porosity smaller than that of the air electrode catalyst layer.
  • the fuel cell of the present invention contains liquid fuel and has a liquid fuel storage chamber having an opening for deriving a vaporized component of the liquid fuel, and the liquid fuel storage chamber is closed. And a gas-liquid separation membrane that permeates the vaporized component of the liquid fuel toward the fuel electrode gas diffusion layer of the fuel electrode.
  • the fuel cell of the present invention is arranged on the fuel electrode side of the membrane electrode assembly, and a fuel distribution mechanism that distributes and supplies fuel to the fuel electrode gas diffusion layer of the fuel electrode, and a liquid material
  • a fuel storage unit may be provided that stores fuel and is connected to the fuel distribution mechanism via a flow path.
  • FIG. 1 is a diagram schematically showing a cross section of a direct methanol fuel cell according to an embodiment of the present invention.
  • FIG. 2 is a diagram schematically showing a cross section of a direct methanol fuel cell having another configuration according to an embodiment of the present invention.
  • FIG. 3 is a perspective view schematically showing a configuration of a fuel distribution mechanism.
  • FIG. 1 is a diagram schematically showing a cross section of a direct methanol fuel cell 10 according to an embodiment of the present invention.
  • the fuel cell 10 includes a fuel electrode composed of a fuel electrode catalyst layer 1 1 and a fuel electrode gas diffusion layer 1 2, an air electrode catalyst layer 1 3, and an air electrode gas diffusion layer 1 4.
  • a membrane electrode assembly comprising an air electrode comprising a fuel electrode catalyst layer 11 and a proton (hydrogen ion) conductive membrane 15 sandwiched between the air electrode catalyst layer 1 3 MEA: Mem brane E lectrode A ss em b I y) 1 6 is provided as an electromotive part.
  • Examples of the catalyst contained in the fuel electrode catalyst layer 1 1 and the air electrode catalyst layer 1 3 include Pt, Ru, Rh, Ir, Os, and Pd, which are platinum group elements. Examples thereof include single metals such as alloys and alloys containing platinum group elements. Specifically, as the fuel electrode catalyst layer 1 1, P t _Ru and P t—Mo having strong resistance to methanol and carbon monoxide, and as the air electrode catalyst layer 1 3, platinum and P t ⁇ N i However, it is not limited to these. In addition, a supported catalyst using a conductive support such as a carbon material or an unsupported catalyst may be used.
  • the fuel electrode catalyst layer 11 and the air electrode catalyst layer 13 are configured to have a predetermined porosity, and the fuel electrode catalyst layer 11 has a porosity equal to that of the air electrode catalyst layer 13. It is set smaller than the rate.
  • the porosity of the fuel electrode catalyst layer 11 is 20 to 80% of the porosity of the air electrode catalyst layer 13 and is preferably 40 to 70%, more preferably 50. ⁇ 70%.
  • the ratio of the porosity of the fuel electrode catalyst layer 11 to the porosity of the air electrode catalyst layer 1 3 is set within this range when the ratio is smaller than 20%. 1 1 Because methanol permeation into the fuel itself decreases and the reforming reaction is not accelerated.
  • the vaporized methanol fuel permeates the fuel electrode catalyst layer 11 and also permeates the electrolyte membrane 15 and crosses over to the air electrode catalyst layer 13. This is because an unnecessary reaction is caused to lower the output potential.
  • the water that has permeated the electrolyte membrane 15 passes through the fuel electrode gas diffusion layer 12 and is then vaporized and mixed into the liquid fuel storage chamber 21.
  • Proton conductive materials constituting the electrolyte membrane 15 include, for example, fluorine resins having a sulfonic acid group, such as a perfluorosulfonic acid polymer (Naphion (trade name, manufactured by DuPont). ), Flemion (trade name, manufactured by Asahi Glass Co., Ltd.), etc., hydrocarbon resins having sulfonic acid groups, inorganic substances such as tungstic acid and phosphotungstic acid, etc., but are not limited thereto.
  • fluorine resins having a sulfonic acid group such as a perfluorosulfonic acid polymer (Naphion (trade name, manufactured by DuPont). ), Flemion (trade name, manufactured by Asahi Glass Co., Ltd.), etc.
  • hydrocarbon resins having sulfonic acid groups such as tungstic acid and phosphotungstic acid, etc., but are not limited thereto.
  • the fuel electrode gas diffusion layer 1 2 laminated on the fuel electrode catalyst layer 1 1 is composed of the fuel electrode catalyst layer 1
  • the air electrode gas diffusion layer 14 stacked on the air electrode catalyst layer 1 3 serves to uniformly supply the oxidant to the air electrode catalyst layer 1 3, and at the same time, collects current from the air electrode catalyst layer 1 3. It also serves as a body.
  • the fuel electrode gas diffusion layer 12 and the air electrode gas diffusion layer 14 pass gas. Therefore, it is made of a known conductive material made of a porous material.
  • the fuel electrode gas diffusion layer 1 2 and the air electrode gas diffusion layer 1 4 are made of, for example, carbon paper, woven fabric, etc., but are not limited thereto.
  • the fuel electrode gas diffusion layer 12 and the air electrode gas diffusion layer 14 are preferably made of a material capable of adjusting the porosity. For example, the volume or the density is changed by compression. It is preferable to use carbon paper that can be used.
  • the porosity of the fuel electrode gas diffusion layer 12 is set to be smaller than the porosity of the air electrode gas diffusion layer 14.
  • the porosity of the fuel electrode gas diffusion layer 12 is 20 to 80% of the porosity of the air electrode gas diffusion layer 14 and preferably 40 to 70%. Preferably it is 50 to 70%.
  • the ratio of the porosity of the fuel electrode gas diffusion layer 1 2 to the porosity of the air electrode gas diffusion layer 14 is set to this range when the ratio is smaller than 20%. This is because it becomes difficult to supply an appropriate amount of vaporized fuel to the fuel electrode catalyst layer 11 through the gas diffusion layer 12.
  • the porosity of the fuel electrode catalyst layer 11 is set to be smaller than the porosity of the air electrode catalyst layer 13
  • the porosity of the fuel electrode gas diffusion layer 12 is It may be set smaller than the porosity of the diffusion layer 14.
  • a fuel electrode conductive layer 17 is stacked on the fuel electrode gas diffusion layer 12, and an air electrode conductive layer 18 is stacked on the air electrode gas diffusion layer 14.
  • the fuel electrode conductive layer 17 and the air electrode conductive layer 18 are made of, for example, a porous layer (for example, a mesh) or a foil body made of a metal material such as a noble metal such as platinum or gold, or a corrosion-resistant metal such as nickel or stainless steel. It is preferable to use gold and carbon. It is possible to use a material obtained by surface-treating an electrically conductive material with a different metal, or a composite material in which copper or stainless steel is coated with a highly conductive metal such as gold.
  • the fuel electrode conductive layer 17 and the air electrode conductive layer 18 are configured so that fuel and an oxidizing agent do not leak from the peripheral edge thereof.
  • a fuel electrode sealing material 19 having a rectangular frame shape is disposed between the fuel electrode conductive layer 17 and the electrolyte membrane 15, and the fuel electrode catalyst layer 11 and the fuel electrode gas Suse diffusion layer 1 2 is surrounded.
  • an air electrode sealing material 20 having a rectangular frame shape is disposed between the air electrode conductive layer 18 and the electrolyte membrane 15, and the air electrode catalyst layer 13 and the air electrode gas diffusion layer 14.
  • the fuel electrode seal material 19 and the air electrode seal material 20 are made of, for example, a rubber O-ring, and prevent fuel leakage and oxidant leakage from the membrane electrode assembly 16.
  • the shapes of the fuel electrode sealing material 19 and the air electrode sealing material 20 are not limited to the rectangular frame shape, and are appropriately configured to correspond to the outer edge shape of the fuel cell 10.
  • a gas-liquid separation membrane 22 is disposed so as to cover the opening of the liquid fuel storage chamber 21 that stores the liquid fuel F.
  • a frame 2 3 (here, a rectangular frame) configured in a shape corresponding to the outer edge shape of the fuel cell 10 is disposed.
  • the membrane electrode assembly 16 having the above-described fuel electrode conductive layer 17 and air electrode conductive layer 18, so that the fuel electrode conductive layer 17 is on the frame 23. They are stacked.
  • the frame 23 is made of an electrically insulating material, and is specifically formed of a thermoplastic polyester resin such as polyethylene terephthalate (PET).
  • the liquid fuel F stored in the liquid fuel storage chamber 21 is a methanol aqueous solution having a concentration exceeding 50 mol% or pure methanol.
  • the purity of the pure methanol is preferably 95% by weight or more and 100% by weight or less.
  • the vaporized component of the liquid fuel F means vaporized methanol when liquid methanol is used as the liquid fuel F, and methanol water as the liquid fuel F. When a solution is used, it means a mixture of methanol vaporizer and water vaporizer.
  • the vaporized fuel storage chamber 2 4 which is a space surrounded by the gas-liquid separation membrane 2 2, the fuel electrode conductive layer 1 7 and the frame 2 3 is a liquid fuel F that has permeated the gas-liquid separation membrane 2 2. It functions as a space that temporarily stores vaporized components and makes the fuel concentration distribution in the vaporized components uniform.
  • the gas-liquid separation membrane 22 described above separates the vaporized component of the liquid fuel F and the liquid fuel F, and allows the vaporized component to permeate the fuel electrode catalyst layer 11 side.
  • This gas-liquid separation membrane 22 is composed of a sheet that is inert to liquid fuel F and does not dissolve, and specifically includes silicone rubber, low-density polyethylene (LDPE) thin film, polyvinyl chloride. (PVC) thin film, polyethylene terephthalate (PET) thin film, fluororesin (for example, polytetrafluoroethylene (PTFE), tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), etc.) Microporous Consists of materials such as membranes.
  • the gas-liquid separation membrane 22 is configured so that fuel or the like does not leak from the periphery.
  • a moisture retaining layer 26 is laminated on the air electrode conductive layer 18 via a frame 25 (here, a rectangular frame) configured in a shape corresponding to the outer edge shape of the fuel cell 10.
  • a frame 25 here, a rectangular frame configured in a shape corresponding to the outer edge shape of the fuel cell 10.
  • a surface cover layer 27 that functions as a surface layer and has a plurality of air inlets 28 for taking in air as an oxidant is laminated.
  • the surface cover layer 27 is also formed of a metal such as SUS 304, for example, by pressing the laminated body including the membrane electrode assembly 16 to enhance its adhesion.
  • the frame 25 is made of an electrically insulating material, like the frame 23 described above.
  • the frame 25 is made of, for example, a thermoplastic polyester resin such as polyethylene terephthalate (PET).
  • the moisturizing layer 26 is impregnated with part of the water generated in the air electrode catalyst layer 13 to suppress water evaporation, and is oxidized in the air electrode gas diffusion layer 14. Uniform diffusion of oxidizing agent into the air electrode catalyst layer 1 3 by introducing the agent uniformly It also has a function as an auxiliary diffusion layer that promotes.
  • the moisturizing layer 26 is made of, for example, a material such as a polyethylene porous membrane, and a membrane having a maximum pore diameter of about 20 to 50 m is used. The reason why the maximum hole diameter is within this range is that the air permeation amount decreases when the hole diameter is smaller than 20 m, and the water evaporation is excessive when the hole diameter is larger than 50 m. It should be noted that the movement of water from the air electrode catalyst layer 1 3 side to the fuel electrode catalyst layer 1 1 side due to the osmotic pressure phenomenon is caused by It can be controlled by changing the number and size and adjusting the area of the opening.
  • the configuration of the fuel cell 10 is not limited to the above-described configuration, and for example, a hydrophobic porous film may be provided between the fuel electrode conductive layer 17 and the frame 23. .
  • a hydrophobic porous film may be provided between the fuel electrode conductive layer 17 and the frame 23.
  • the porous membrane By providing this porous membrane, it is possible to prevent water from entering from the fuel electrode gas diffusion layer 12 side through the porous membrane into the vaporized fuel storage chamber 24 side.
  • Specific examples of the material for the porous film include polytetrafluoroethylene (PTFE) and a water-repellent treated silicone sheet.
  • the gas-liquid separation membrane 22 has a gas-liquid separation function similar to that of the gas-liquid separation membrane 22 on the liquid fuel storage chamber 21 side, and further adjusts the permeation amount of the vaporized component of the fuel.
  • a permeation amount adjusting film may be provided. The permeation amount of the vaporized component by the permeation amount adjusting membrane is adjusted by adjusting the diameter of the opening provided in the permeation amount adjusting membrane.
  • This permeation amount adjusting film can be made of a material such as polyethylene terephthalate, for example.
  • the liquid fuel F for example, aqueous methanol solution
  • the liquid fuel F in the liquid fuel storage chamber 21 is vaporized, and the vaporized mixture of methanol and water vapor passes through the gas-liquid separation membrane 22 and passes through the vaporized fuel storage chamber 2
  • concentration distribution is made uniform.
  • the air-fuel mixture once stored in the vaporized fuel storage chamber 24 passes through the fuel electrode conductive layer 17, is further diffused in the fuel electrode gas diffusion layer 12, and is supplied to the fuel electrode catalyst layer 11.
  • the gas mixture supplied to the fuel electrode catalyst layer 1 1 is the methanol internal reforming reaction shown in the following equation (1). Produce a response.
  • Proton (H +) generated by the internal reforming reaction is conducted through the electrolyte membrane 15 and reaches the air electrode catalyst layer 13.
  • the air taken in from the air inlet 28 of the surface cover layer 27 diffuses through the moisturizing layer 26, the air electrode conductive layer 18, and the air electrode gas diffusion layer 14, and is supplied to the air electrode catalyst layer 13. .
  • the air supplied to the air electrode catalyst layer 13 causes the reaction shown in the following formula (2). This reaction generates water and generates a power generation reaction.
  • the porosity of the fuel electrode gas diffusion layer 12 is smaller than the porosity of the air electrode gas diffusion layer 14, the water that has permeated the electrolyte membrane 15 is Since it becomes difficult to pass through the polar gas diffusion layer 12, a decrease in fuel concentration that occurs on the liquid fuel storage chamber 21 side from the fuel electrode gas diffusion layer 12 is suppressed.
  • the chemical reaction with the vaporized methanol that has permeated through the fuel electrode gas diffusion layer 12 is maintained. be able to. As a result, it is possible to maintain a stable output density for a long period of time.
  • the porosity of the fuel electrode gas diffusion layer 12 is set smaller than the porosity of the air electrode gas diffusion layer 14 has been described.
  • the porosity of the fuel electrode catalyst layer 11 is The same effect can be obtained when the porosity is set smaller than the porosity of the air electrode catalyst layer 13.
  • the porosity of the anode gas diffusion layer 12 The same effect can be obtained when the porosity of the gas diffusion layer 14 is set smaller than that of the fuel electrode catalyst layer 11 and the porosity of the fuel electrode catalyst layer 11 is set smaller than that of the air electrode catalyst layer 13.
  • the porosity of the fuel electrode gas diffusion layer 12 is set smaller than the porosity of the air electrode gas diffusion layer 14. And / or by setting the porosity of the fuel electrode catalyst layer 1 1 to be smaller than the porosity of the air electrode catalyst layer 1 3, water generated at the air electrode can be retained in the fuel electrode. The water can be prevented from entering the liquid fuel storage chamber 21 from the anode gas diffusion layer 12. As a result, it is possible to suppress a decrease in fuel concentration that occurs on the liquid fuel storage chamber 21 side from the fuel electrode gas diffusion layer 12, and to supply a predetermined concentration of fuel to the fuel electrode catalyst layer 11. Therefore, it is possible to suppress a decrease in fuel cell output due to continuous operation.
  • the porosity of the fuel electrode gas diffusion layer 12 is set to be smaller than the porosity of the air electrode gas diffusion layer 14 and / or the porosity of the fuel electrode catalyst layer 11 is set to the air electrode catalyst.
  • the porosity of the layer 13 it is possible to supply a sufficient amount of oxygen for the reaction that occurs in the air electrode catalyst layer 13. It is possible to suppress a decrease in output.
  • liquid fuel is not limited to these. Absent.
  • ethanol fuel such as ethanol aqueous solution or pure ethanol
  • propanol fuel such as propanol aqueous solution or pure propanol
  • glycol fuel such as glycol aqueous solution, dimethyl ether, formic acid, or other liquid fuel
  • the present invention can be applied to an active type fuel cell, and also to a semi-passive type fuel cell using a pump or the like for a part of the fuel supply, etc. The same operation effect as the case where there was was obtained.
  • FIG. 2 is a diagram schematically showing a cross section of a direct methanol fuel cell 100 having another configuration according to an embodiment of the present invention.
  • FIG. 3 is a perspective view schematically showing the configuration of the fuel distribution mechanism 1 30. Note that the same components as those of the fuel cell 10 according to the embodiment described above are denoted by the same reference numerals, and redundant description is omitted or simplified.
  • the membrane electrode assembly 16 includes a fuel electrode composed of a fuel electrode catalyst layer 11 and a fuel electrode gas diffusion layer 12, an air electrode catalyst layer 13 and an air electrode gas diffusion layer.
  • 14 is composed of an air electrode composed of 14 and a proton (hydrogen ion) conductive electrolyte membrane 15 sandwiched between a fuel electrode catalyst layer 1 1 and an air electrode catalyst layer 1 3.
  • the fuel electrode sealing material 1 9 force Between the electrolyte membrane 15 and the surface cover layer 2 7, the air electrode sealing material 20 These prevent fuel leakage and oxidant leakage from the membrane electrode assembly 16.
  • An air inlet port 28 for taking in air as an oxidant is formed in the surface cover layer 27.
  • a moisture retaining layer or the like is disposed between the surface cover layer 27 and the air electrode 1 1 1 as necessary.
  • the moisturizing layer is impregnated with a part of the water generated in the air electrode catalyst layer 1 3 to suppress the transpiration of water and promote the uniform diffusion of air to the air electrode catalyst layer 1 3. .
  • a fuel distribution mechanism 130 is arranged on the fuel electrode side of the membrane electrode assembly 16.
  • a fuel storage part 1 3 2 is connected to the fuel distribution mechanism 1 3 0 via a fuel flow path 1 3 1 such as a pipe.
  • Liquid fuel F corresponding to the membrane electrode assembly 16 is accommodated in the fuel accommodating portion 1 3 2.
  • the liquid fuel F include methanol fuels such as methanol aqueous solutions of various concentrations and pure methanol.
  • Liquid fuel F is not necessarily methanol fuel It is not limited to fees.
  • Liquid fuel F is, for example, ethanol fuel such as ethanol aqueous solution, propanol fuel such as propanol aqueous solution or pure propanol, glycol fuel such as glycol aqueous solution or pure glycol, dimethyl ether, formic acid, and other liquid fuels. May be.
  • fuel corresponding to the fuel cell 100 is accommodated in the fuel accommodating portion 13 2.
  • Liquid fuel F is introduced into the fuel distribution mechanism 1 30 from the fuel storage portion 1 3 2 through the flow path 1 3 1.
  • the flow path 1 3 1 is not limited to being constituted by a pipe independent of the fuel distribution mechanism 1 3 0 and the fuel storage part 1 3 2.
  • a liquid fuel flow path connecting them may be used.
  • the fuel distribution mechanism 1 3 0 only needs to be connected to the fuel storage portion 1 3 2 via the flow path 1 3 1.
  • the fuel distribution mechanism 1 3 0 includes at least one fuel inlet 1 3 3 into which the liquid fuel F flows through the flow path 1 3 1, and the liquid fuel F And a fuel distribution plate 1 3 5 having a plurality of fuel discharge ports 1 3 4 for discharging the vaporized components.
  • a gap portion 1 36 is provided inside the fuel distribution plate 1 35 as a passage for the liquid fuel F guided from the fuel inlet 1 33.
  • the plurality of fuel discharge ports 1 3 4 are in direct communication with the gaps 1 3 6 that function as fuel passages.
  • the liquid fuel F introduced into the fuel distribution mechanism 1 3 0 from the fuel inlet 1 3 3 flows into the gap portion 1 3 6 that functions as a fuel passage, and a plurality of gaps are formed via the gap portion 1 3 6. Leaded to each of the fuel outlets 1 3 4.
  • a gas-liquid separator (not shown) that transmits only the vaporized component of the fuel and does not transmit the liquid component may be disposed in the plurality of fuel discharge ports 1 3 4.
  • the gas-liquid separator may be installed as a gas-liquid separation film between the fuel distribution mechanism 1 30 and the fuel electrode 1 10.
  • the vaporized component of the liquid fuel F is discharged from the plurality of fuel discharge ports 1 3 4 toward the fuel electrode 1 1 0.
  • the fuel outlet 1 3 4 can supply fuel to the entire membrane electrode assembly 1 6. For this reason, a plurality of fuel distribution plates 1 3 5 are provided on the surface in contact with the fuel electrode 1 1 0.
  • the number of fuel outlets 1 3 4 may be two or more, but in order to uniformize the fuel supply amount in the surface of the membrane electrode assembly 16, 0.1 to 10 pieces / cm 2 of fuel Preferably, the outlets 1 3 4 are formed.
  • a pump 1 3 7 is inserted into a flow path 1 3 1 that connects between the fuel distribution mechanism 1 30 and the fuel storage portion 1 3 2.
  • the pump 1 37 is not a circulation pump through which the liquid fuel F is circulated, but is merely a fuel supply pump that transfers the liquid fuel F from the fuel storage portion 1 32 to the fuel distribution mechanism 1 30.
  • the controllability of the fuel supply amount is enhanced.
  • the pump 1 3 7 a small amount of liquid fuel F can be fed with good controllability, and from the viewpoint that it is possible to reduce the size and weight, rotary vane pumps, electroosmotic flow pumps, diaphragm pumps, iron pumps Etc. are preferably used.
  • the rotary vane pump feeds liquid by rotating wings with a motor.
  • the electroosmotic pump uses a sintered porous material such as sili-force that causes the electroosmotic flow phenomenon.
  • the diaphragm pump feeds liquid by driving the diaphragm with an electromagnet or piezoelectric ceramic.
  • the iron pump pumps the liquid fuel F by pressing a part of the flexible fuel flow path.
  • an electroosmotic pump or a diaphragm pump having piezoelectric ceramics from the viewpoints of driving power and size.
  • the liquid fuel F stored in the fuel storage portion 13 2 is transferred to the flow path 13 1 by the pump 1 37 and supplied to the fuel distribution mechanism 1 30.
  • the fuel released from the fuel distribution mechanism 1 3 0 is supplied to the fuel electrode 1 1 0 of the membrane electrode assembly 1 6.
  • the subsequent operation is the same as that in the fuel cell 10 described above.
  • a fuel shut-off valve is arranged instead of the pump 1 3 7. Is also possible. In this case, the fuel shut-off valve is Provided to control the supply of liquid fuel F.
  • the porosity of the fuel electrode gas diffusion layer 12 is set to be smaller than the porosity of the air electrode gas diffusion layer 14 and / or the porosity of the fuel electrode catalyst layer 11 is set to the air electrode catalyst.
  • the following example demonstrates that excellent output characteristics can be obtained in the fuel cell 10 set to be smaller than the porosity of the layer 13.
  • the fuel cell according to the present invention was produced as follows.
  • a single-pong paper (TGP-H-120 manufactured by Toray Industries, Inc.) was compressed with a flat plate press until the thickness became 1/2.
  • the porosity of this one-pump paper before compression was 75% as measured by the Archimedes method.
  • the porosity of the carbon paper after compression was 40.5% as a result of calculation based on the external dimensions and weight measurement.
  • This one-pump paper was used as the anode gas diffusion layer.
  • a platinum supported graphite particle and DE2020 manufactured by DuPont were mixed with a homogenizer to produce a slurry, and this was used as a power pump with a porosity of 75% as an air electrode gas diffusion layer. It was applied to one side of a paper (TGP-H-1 20 manufactured by Toray Industries, Inc.). And this was dried at normal temperature, the air electrode catalyst layer was formed, and the air electrode was produced.
  • the porosity of the air electrode catalyst layer was 88.1% as a result of calculation based on the coating film dimensions, material density, and measured weight. The material density is al Obtained by the Chimedes method.
  • the electrolyte membrane As the electrolyte membrane, a fixed electrolyte membrane naphthion 1 1 2 (manufactured by DuPont) was used. First, the electrolyte membrane and the air electrode were overlapped so that the catalyst layer was on the electrolyte membrane side, and the temperature was 120 ° C. The pressing was performed under the condition that the pressure was 40 kgf / cm 2 . Subsequently, the fuel electrode is overlaid on the opposite side of the air electrode of the electrolyte membrane so that the catalyst layer is on the electrolyte membrane side, the temperature is 120 ° C, and the pressure is 1 O kgf / cm 2 The membrane electrode assembly (MEA) was fabricated by pressing under conditions. The electrode area was 12 cm 2 for both the air electrode and the fuel electrode.
  • MEA membrane electrode assembly
  • the membrane electrode assembly was sandwiched between gold foils having a plurality of openings for taking in air and vaporized methanol to form a fuel electrode conductive layer and an air electrode conductive layer.
  • a laminate in which the membrane electrode assembly (MEA), the fuel electrode conductive layer, and the air electrode conductive layer described above were stacked was sandwiched between two resin-made frames.
  • a rubber O-ring is sandwiched between the air electrode side of the membrane electrode assembly and one frame, and between the fuel electrode side of the membrane electrode assembly and the other frame. did.
  • the frame on the fuel electrode side was fixed to the liquid fuel storage chamber with a screw through a gas-liquid separation membrane.
  • a gas-liquid separation membrane a 0.2 mm thick silicone sheet was used.
  • a porous plate with a porosity of 28% was placed on the air electrode side frame to form a moisture retention layer.
  • a stainless steel plate SUS 304 with a thickness of 2 mm and air inlets (4 mm diameter, 64 holes) for air intake is formed to form one surface cover. And fixed with screws.
  • the maximum value of the output was 1 2.2 mW / cm 2 and the maximum value of the surface temperature of the fuel cell was 32.4 ° C.
  • 15mI of pure methanol was injected into the liquid fuel storage chamber of the fuel cell, the voltage was regulated to 0.3 V, the battery was continuously operated, and the current density was measured. The output change was measured. As a result, the output reduction rate after 60 hours was 8.1%.
  • the output decrease rate after 60 hours is the ratio of the output decreased after 60 hours from the start of operation to the output at the start of operation.
  • the ME cell was removed from the cell, cut and embedded in the resin so that the cross-section was visible.
  • the ME A embedded in this resin was polished so that the cross section was flat and observed with an electron microscope. From the results, the thicknesses of the fuel electrode catalyst layer and the air catalyst layer were measured at 10 points, and the average thickness was obtained.
  • the porosity of the catalyst layer was calculated from the thickness, material density, and measured weight, and the fuel electrode catalyst layer was 68.8% and the air electrode catalyst layer was 62.1%.
  • Example 2 In the production of the fuel cell used in Example 2, first, carbon particles carrying platinum ruthenium alloy fine particles and DE 2020 (manufactured by DuPont) were mixed with a homogenizer to produce a slurry, which was then used as the fuel electrode. The gas diffusion layer was applied to one side of a force-per-pump paper (TG P—H—120, manufactured by Toray Industries, Inc.) with a porosity of 75%. Then, this was dried at room temperature to form a fuel electrode catalyst layer, and a fuel electrode was produced.
  • TG P—H—120 manufactured by Toray Industries, Inc.
  • a PTFE (polytetrafluoroethylene) sheet is disposed on the fuel electrode catalyst layer
  • a 0.5 mm thick silicone rubber sheet is disposed on the PTFE (polytetrafluoroethylene) sheet
  • a flat plate press did.
  • the thickness of the fuel electrode catalyst layer was about 2/3
  • the porosity of the fuel electrode catalyst layer was calculated to be 66.4% based on the coating film dimensions, material density, and measured weight. In this flat plate press, the thickness of the anode gas diffusion layer did not change.
  • electrolyte membrane As the electrolyte membrane, a fixed electrolyte membrane naphthion 1 1 2 (manufactured by DuPont) was used, and this electrolyte membrane was sandwiched between the air electrode and the fuel electrode so that the catalyst coating layer was on the electrolyte membrane side, and the temperature was 120 ° C.
  • a membrane electrode assembly (MEA) was fabricated by pressing under the conditions of 40 kgf / cm 2 pressure. The electrode area is 1 for both the air electrode and the fuel electrode.
  • the maximum value of the output was 11.8 mW / cm 2 , and the maximum value of the surface temperature of the fuel cell was 31.5 ° C. Further, the rate of decrease in output after 60 hours was 9.2%.
  • This ME A was taken out of the cell, cut and embedded in a resin so that the cross section could be seen.
  • the ME A embedded in this resin was polished so that the cross section was flat and observed with an electron microscope. From the results, the thicknesses of the fuel electrode catalyst layer and the air catalyst layer were measured about 10 points each, and the average thickness was determined. The porosity of the catalyst layer was calculated from the thickness, material density, and measured weight.
  • a PTFE (polytetrafluoroethylene) sheet is disposed on the fuel electrode catalyst layer, a 0.5 mm thick silicone rubber sheet is disposed thereon, and compressed by a flat plate press.
  • the porosity of the fuel electrode catalyst layer was 65.5% as a result of calculation based on the coating film dimensions, material density, and measured weight.
  • the thickness of the anode gas diffusion layer did not change.
  • a platinum-supported graphite particle and DE 2020 (manufactured by DuPont) were mixed with a homogenizer to produce a slurry, which was used as the air electrode gas diffusion layer with a porosity of 75%. It was applied to one side of Pompepa (TGP-H-1 20 manufactured by Toray Industries, Inc.). And this was dried at normal temperature, the air electrode catalyst layer was formed, and the air electrode was produced. The porosity of the air electrode catalyst layer was 88.0% as calculated from the coating film dimensions, material density, and measured weight.
  • electrolyte membrane As the electrolyte membrane, a fixed electrolyte membrane naphthion 1 1 2 (manufactured by DuPont) was used, and this electrolyte membrane was sandwiched between the air electrode and the fuel electrode so that the catalyst coating layer was on the electrolyte membrane side, and the temperature was 120 ° C.
  • a membrane electrode assembly (MEA) was fabricated by pressing under the conditions of 40 kgf / cm 2 pressure. The electrode area was 12 cm 2 for both the air electrode and the fuel electrode. The other configuration is the same as that of the fuel cell of Example 1.
  • the measurement method and measurement conditions of the maximum output value, the maximum value of the surface temperature of the fuel cell, and the output reduction rate after 60 hours are the same as the measurement method and measurement conditions in Example 1.
  • the maximum value of the output was 1 1.7 mW / cm 2
  • the maximum value of the surface temperature of the fuel cell was 31.2 ° C.
  • the rate of decrease in output after 60 hours was 8.3%.
  • the ME A was taken out of the cell, cut and embedded in a resin so that the cross section could be seen.
  • the cross section of ME A embedded in this resin is flat. Polished and observed with an electron microscope. From the results, the thicknesses of the fuel electrode catalyst layer and the air catalyst layer were measured about 10 points each, and the average thickness was determined. The porosity of the catalyst layer was calculated from the thickness, material density, and measured weight.
  • the configuration of the fuel cell used in Comparative Example 1 was the same as that of the fuel electrode gas diffusion layer, except that a carbon vapor with a porosity of 75% (TGP-H—120 from Toray Industries, Inc.) was used.
  • the configuration of the fuel cell in Example 1 is the same.
  • the maximum value of the output was 12 mW / cm 2 and the maximum value of the surface temperature of the fuel cell was 38.6 ° C. Further, the output decrease rate after 60 hours was 20.5%. In the fuel cell used in Comparative Example 1, fuel consumption was fast and the time until the fuel in the liquid fuel storage chamber was emptied was short.
  • the ME A was taken out of the cell, cut and embedded in a resin so that the cross section could be seen.
  • the ME A embedded in this resin was polished so that the cross section was flat and observed with an electron microscope. From the results, the thicknesses of the fuel electrode catalyst layer and the air catalyst layer were measured about 10 points each, and the average thickness was determined.
  • the porosity of the catalyst layer was calculated from the thickness, material density, and measured weight, and found to be 69.2% for the fuel electrode catalyst layer and 63.3% for the air electrode catalyst layer.
  • Table 1 shows the measurement results of Examples 1 to 3 and Comparative Example 1 described above.
  • the output reduction rate after 60 hours was larger in Comparative Example 1 than in Examples 1 to 3.
  • the output decrease rate after 60 hours is high.
  • a part of the water permeated from the air electrode side to the fuel electrode side passes through the fuel electrode gas diffusion layer. This is thought to be due to the fact that water vapor passes through the gas-liquid separation membrane and flows into the liquid fuel storage chamber, and the methanol concentration in the liquid fuel storage chamber decreases.
  • the output reduction rate after 60 hours is low.
  • the porosity of the anode gas diffusion layer is set to the cathode gas.
  • the fuel cell system is not limited to the passive type as long as the structure uses water generated by the reaction on the fuel electrode side. It is not limited.
  • the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
  • liquid fuel vapor supplied to the membrane electrode assembly may be supplied entirely, but even if a part of the liquid fuel vapor is supplied in a liquid state.
  • the present invention can be applied.
  • the porosity of the fuel electrode gas diffusion layer is set to be smaller than the porosity of the air electrode gas diffusion layer, and / or the porosity of the fuel electrode catalyst layer.
  • water generated in the air electrode can be retained in the fuel electrode, and this water enters the liquid fuel storage chamber side from the fuel electrode gas diffusion layer. Can be suppressed.
  • a decrease in the output of the fuel cell due to operation can be suppressed.
  • the fuel cell according to the embodiment of the present invention is effectively used for, for example, a liquid fuel direct supply type fuel cell.

Landscapes

  • 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)
  • Inert Electrodes (AREA)

Abstract

Une batterie (10) de piles à combustible comprend une électrode à combustible ayant une couche (11) de catalyseur d'électrode à combustible et une couche (12) de diffusion de gaz d'électrode à combustible, disposée de façon à être tournée vers un côté de la couche (11) de catalyseur d'électrode à combustible, une électrode oxydoréductrice ayant une couche (13) de catalyseur d'électrode oxydoréductrice et une couche (14) de diffusion de gaz d'électrode oxydoréductrice disposée de façon à être tournée vers un côté de la couche (13) de catalyseur d'électrode oxydoréductrice, et un ensemble membrane-électrode (16) composé d'une membrane électrolytique (15) prise en sandwich entre la couche (11) de catalyseur d'électrode à combustible et la couche (13) de catalyseur d'électrode oxydoréductrice. La porosité de la couche (13) de diffusion de gaz d'électrode à combustible est inférieure à celle de la couche (14) de diffusion de gaz d'électrode oxydoréductrice.
PCT/JP2007/001279 2006-11-27 2007-11-21 Pile à combustible WO2008068887A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2008548160A JPWO2008068887A1 (ja) 2006-11-27 2007-11-21 燃料電池

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2006318991 2006-11-27
JP2006-318991 2006-11-27

Publications (1)

Publication Number Publication Date
WO2008068887A1 true WO2008068887A1 (fr) 2008-06-12

Family

ID=39491804

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2007/001279 WO2008068887A1 (fr) 2006-11-27 2007-11-21 Pile à combustible

Country Status (3)

Country Link
JP (1) JPWO2008068887A1 (fr)
TW (1) TW200836394A (fr)
WO (1) WO2008068887A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012161206A1 (fr) * 2011-05-24 2012-11-29 シャープ株式会社 Pile à combustible
CN106505235A (zh) * 2016-11-14 2017-03-15 中国科学院上海高等研究院 阳极保湿结构及采用其的被动式直接甲醇燃料电池
CN111566859A (zh) * 2017-12-28 2020-08-21 松下知识产权经营株式会社 燃料电池用催化剂层、膜电极接合体及燃料电池

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001017047A1 (fr) * 1999-08-27 2001-03-08 Matsushita Electric Industrial Co., Ltd. Cellule electrochimique de type a electrolyte polymerique

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001017047A1 (fr) * 1999-08-27 2001-03-08 Matsushita Electric Industrial Co., Ltd. Cellule electrochimique de type a electrolyte polymerique

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012161206A1 (fr) * 2011-05-24 2012-11-29 シャープ株式会社 Pile à combustible
JP2012243722A (ja) * 2011-05-24 2012-12-10 Sharp Corp 燃料電池
CN106505235A (zh) * 2016-11-14 2017-03-15 中国科学院上海高等研究院 阳极保湿结构及采用其的被动式直接甲醇燃料电池
CN111566859A (zh) * 2017-12-28 2020-08-21 松下知识产权经营株式会社 燃料电池用催化剂层、膜电极接合体及燃料电池
US11682770B2 (en) 2017-12-28 2023-06-20 Panasonic Intellectual Property Management Co., Ltd. Catalyst layer for fuel cell, membrane electrode assembly, and fuel cell

Also Published As

Publication number Publication date
TW200836394A (en) 2008-09-01
JPWO2008068887A1 (ja) 2010-03-18

Similar Documents

Publication Publication Date Title
WO2006038519A1 (fr) Pile a combustible et procede de generation d’energie
WO2008088319A2 (fr) Electrodes d'anode pour piles à combustible à oxydation directe et systèmes fonctionnant avec un combustible liquide concentré
JPWO2007123066A1 (ja) 固体高分子型燃料電池
JP2006108028A (ja) 燃料電池
US20110275003A1 (en) Fuel cell
US20110117465A1 (en) Fuel cell
WO2008032449A1 (fr) Membrane électrolytique et pile à combustible
JP2008293856A (ja) 燃料電池
WO2008068887A1 (fr) Pile à combustible
WO2008068886A1 (fr) Batterie de piles à combustible
WO2006106969A1 (fr) Pile à combustible
JP5071378B2 (ja) 燃料電池
JP2011096460A (ja) 燃料電池用カソード電極および燃料電池
JP2006049115A (ja) 燃料電池
JP2008293705A (ja) 膜電極接合体および燃料電池
JP2008310995A (ja) 燃料電池
JP5127267B2 (ja) 燃料電池および燃料電池システム
WO2011052650A1 (fr) Pile à combustible
JP2009146864A (ja) 燃料電池
JP2011096468A (ja) 燃料電池
JP2010244919A (ja) 燃料電池システム、燃料電池システムの制御方法
JP2010003562A (ja) 膜電極接合体及び燃料電池
JP2007157593A (ja) 燃料電池
JP2009038014A (ja) 燃料電池および燃料電池の製造方法
JP2009123619A (ja) 燃料電池

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07828056

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2008548160

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 07828056

Country of ref document: EP

Kind code of ref document: A1