WO2010084751A1 - Fuel battery - Google Patents

Fuel battery Download PDF

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Publication number
WO2010084751A1
WO2010084751A1 PCT/JP2010/000318 JP2010000318W WO2010084751A1 WO 2010084751 A1 WO2010084751 A1 WO 2010084751A1 JP 2010000318 W JP2010000318 W JP 2010000318W WO 2010084751 A1 WO2010084751 A1 WO 2010084751A1
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WO
WIPO (PCT)
Prior art keywords
fuel
fuel cell
liquid
cell according
distribution mechanism
Prior art date
Application number
PCT/JP2010/000318
Other languages
French (fr)
Japanese (ja)
Inventor
吉田勇一
根岸信保
Original Assignee
株式会社 東芝
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Publication of WO2010084751A1 publication Critical patent/WO2010084751A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • 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
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04186—Arrangements for control of reactant parameters, e.g. pressure or concentration of liquid-charged or electrolyte-charged reactants
    • 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
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04201—Reactant storage and supply, e.g. means for feeding, pipes
    • 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]
    • 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 using liquid fuel.
  • a fuel cell is characterized in that it can generate electric power simply by supplying fuel and air, and can generate electric power continuously for a long time if fuel is replenished. For this reason, if the fuel cell can be reduced in size, it can be said that the system is extremely advantageous as a power source for portable electronic devices.
  • Direct methanol fuel cells are promising as power sources for portable electronic devices because they can be miniaturized and the fuel can be easily handled.
  • DMFC Direct methanol fuel cells
  • an active method such as a gas supply type and a liquid supply type
  • a passive method such as an internal vaporization type in which the liquid fuel in the fuel container is vaporized inside the cell and supplied to the fuel electrode. It has been.
  • passive methods such as an internal vaporization type are particularly advantageous for downsizing of the DMFC.
  • a structure is proposed in which a membrane electrode assembly (fuel cell) having a fuel electrode, an electrolyte membrane, and an air electrode is disposed on a fuel containing portion made of a resin box-like container (for example, see Patent Document 1.)
  • fuel cell fuel cell
  • an electrolyte membrane electrolyte membrane
  • an air electrode is disposed on a fuel containing portion made of a resin box-like container.
  • Patent Document 3 describes increasing the capillary force by hydrophilizing the surface of a fuel supply channel.
  • the fuel supply cannot be sufficiently stabilized only by hydrophilization treatment.
  • a fuel cell includes a membrane electrode assembly including a fuel electrode, an air electrode, and an electrolyte membrane sandwiched between the fuel electrode and the air electrode, and the fuel of the membrane electrode assembly.
  • a fuel distribution mechanism that is disposed on the pole side and has a plurality of fuel discharge holes that distribute and supply fuel to a plurality of locations of the fuel electrode, and accommodates liquid fuel and is connected to the fuel distribution mechanism via a flow path comprising a fuel receiving portion is, the fuel discharge hole of the fuel distribution mechanism, the circumferential length L is characterized by having a circumferential length L 0 greater than the cross-sectional shape of a true circle ditto area S.
  • the circumferential length L is the fuel is supplied to the fuel electrode from the fuel discharge hole having a circumferential length L 0 greater than the cross-sectional shape of a true circle ditto area S,
  • the supply of fuel to the fuel cell can be sufficiently stabilized without impairing the miniaturization of the fuel cell.
  • FIG. 2 is a plan view showing the internal structure of a fuel distribution mechanism used in the fuel cell shown in FIG. It is a top view which shows the cross-sectional example of the fuel discharge hole of the fuel distribution mechanism used with the fuel cell shown in FIG. It is (a) sectional drawing and (b) top view which expand and show the principal part of the fuel distribution mechanism used with the fuel cell shown in FIG. It is sectional drawing which shows the modification of the fuel cell shown in FIG.
  • FIG. 7 is a cross-sectional view showing another modification of the fuel cell shown in FIG. 1.
  • FIG. 1 is a cross-sectional view showing a configuration of a fuel cell according to an embodiment of the present invention.
  • a fuel cell 1 shown in FIG. 1 includes a fuel cell 2 constituting an electromotive unit, a fuel distribution mechanism 3 that supplies fuel to the fuel cell 2, a fuel storage unit 4 that stores liquid fuel, and these fuels. It is mainly composed of a flow path 5 that connects the distribution mechanism 3 and the fuel storage portion 4.
  • the fuel cell 2 includes an anode (fuel electrode) 13 having an anode catalyst layer 11 and an anode gas diffusion layer 12, and a cathode (air electrode / oxidant electrode) 16 having a cathode catalyst layer 14 and a cathode gas diffusion layer 15. And a membrane electrode assembly (MEA) composed of a proton (hydrogen ion) conductive electrolyte membrane 17 sandwiched between the anode catalyst layer 11 and the cathode catalyst layer 14.
  • MEA membrane electrode assembly
  • Examples of the catalyst contained in the anode catalyst layer 11 and the cathode catalyst layer 14 include a simple substance of a platinum group element such as Pt, Ru, Rh, Ir, Os, and Pd, an alloy containing the platinum group element, and the like.
  • the anode catalyst layer 11 is preferably made of Pt—Ru, Pt—Mo, or the like that has strong resistance to methanol, carbon monoxide, or the like.
  • Pt, Pt—Ni or the like is preferably used for the cathode catalyst layer 14.
  • the catalyst is not limited to these, and various substances having catalytic activity can be used.
  • the catalyst may be either a supported catalyst using a conductive support such as a carbon material or an unsupported catalyst.
  • Examples of the proton conductive material constituting the electrolyte membrane 17 include fluorine-based resins (Nafion (trade name, manufactured by DuPont) and Flemion (trade name, manufactured by Asahi Glass Co., Ltd.) such as a perfluorosulfonic acid polymer having a sulfonic acid group. Etc.), organic materials such as hydrocarbon resins having sulfonic acid groups, or inorganic materials such as tungstic acid and phosphotungstic acid.
  • fluorine-based resins Nafion (trade name, manufactured by DuPont) and Flemion (trade name, manufactured by Asahi Glass Co., Ltd.)
  • organic materials such as hydrocarbon resins having sulfonic acid groups
  • inorganic materials such as tungstic acid and phosphotungstic acid.
  • the proton conductive electrolyte membrane 17 is not limited to these.
  • the anode gas diffusion layer 12 laminated on the anode catalyst layer 11 serves to uniformly supply fuel to the anode catalyst layer 11 and also serves as a current collector for the anode catalyst layer 11.
  • the cathode gas diffusion layer 15 laminated on the cathode catalyst layer 14 serves to uniformly supply the oxidant to the cathode catalyst layer 14 and also serves as a current collector for the cathode catalyst layer 14.
  • the anode gas diffusion layer 12 and the cathode gas diffusion layer 15 are made of a porous substrate.
  • a conductive layer (not shown) is laminated on the anode gas diffusion layer 12 and the cathode gas diffusion layer 15 as necessary.
  • these conductive layers for example, a porous layer (for example, a mesh) or a foil body, a porous film, a thin film, or a conductive metal material such as stainless steel (SUS) made of a conductive metal material such as Au or Ni.
  • SUS stainless steel
  • a composite material coated with a highly conductive metal such as Au is used.
  • a cover plate 18 is laminated on the fuel cell (MEA) 2, and a rubber O-ring is provided between the cover plate 18 and the electrolyte membrane 17 and between the electrolyte membrane 17 and the fuel distribution mechanism 3. 19 is interposed. O-ring 19 prevents fuel leakage and oxidant leakage from the fuel cell (MEA) 2.
  • the cover plate 18 has an opening for taking in air as an oxidant.
  • a moisture retaining layer and a surface layer are disposed between the cover plate 18 and the cathode 16 as necessary.
  • the moisturizing layer is impregnated with a part of the water generated in the cathode catalyst layer 14 to suppress the transpiration of water and promote uniform diffusion of air to the cathode catalyst layer 14.
  • the surface layer adjusts the amount of air taken in, and has a plurality of air inlets whose number, size, etc. are adjusted according to the amount of air taken in.
  • the fuel storage unit 4 stores liquid fuel corresponding to the fuel battery cell 2.
  • the liquid fuel include methanol fuels such as aqueous methanol solutions of various concentrations and pure methanol.
  • the liquid fuel is not limited to methanol fuel.
  • the liquid fuel may be, for example, an ethanol fuel such as an ethanol aqueous solution or pure ethanol, a propanol fuel such as a propanol aqueous solution or pure propanol, a glycol fuel such as a glycol aqueous solution or pure glycol, dimethyl ether, formic acid, or other liquid fuel.
  • Liquid fuel corresponding to the fuel cells 2 is stored in the fuel storage unit 4.
  • a fuel distribution mechanism 3 is arranged on the anode 13 side of the fuel battery cell 2.
  • the fuel distribution mechanism 3 is connected to the fuel storage portion 4 through a liquid fuel flow path 5 such as a pipe. Liquid fuel is introduced into the fuel distribution mechanism 3 from the fuel storage portion 4 through the flow path 5.
  • the flow path 5 is not limited to piping independent of the fuel distribution mechanism 3 and the fuel storage unit 4. For example, when the fuel distribution mechanism 3 and the fuel storage unit 4 are stacked and integrated, a liquid fuel flow path connecting them may be used.
  • the fuel distribution mechanism 3 only needs to be connected to the fuel storage portion 4 via the flow path 5.
  • the fuel distribution mechanism 3 includes a fuel distribution plate 23 having at least one fuel injection hole 21 through which liquid fuel flows through the flow path 5 and a plurality of fuel discharge holes 22 through which liquid fuel and vaporized components thereof are discharged.
  • the material for forming the fuel distribution plate 23 is not particularly limited as long as the liquid fuel does not permeate and is not eroded by the liquid fuel, and various materials can be used. Specifically, for example, resin, carbon material, metal and the like can be mentioned.
  • a thin tube 25 that functions as a liquid fuel passage is provided inside the fuel distribution plate 23.
  • the narrow tube 25 extends in a branch shape in the surface direction of the fuel electrode, and one end (starting end portion) thereof is connected to the fuel injection hole 21.
  • the thin tubes 25 are branched into a plurality of portions along the way, and fuel discharge holes 22 are provided at the end portions of the branched thin tubes 25, respectively.
  • the number of the fuel discharge holes 22 may be two or more. However, in order to equalize the fuel supply amount in the surface of the fuel cell 2, there are 0.1 to 10 / cm 2 fuel discharge holes 22. It is preferable to form so as to.
  • the thin tube 25 is preferably a through hole having an inner diameter of 0.05 to 5 mm, for example.
  • the liquid fuel introduced into the fuel distribution mechanism 3 from the fuel injection hole 21 is led to the plurality of fuel discharge holes 22 through the thin tubes 25 functioning as fuel passages, and discharged toward a plurality of locations of the anode 13.
  • a gas-liquid separator (not shown) that transmits only the vaporized component of the liquid fuel and does not transmit the liquid component may be disposed.
  • the gas-liquid separator may be disposed in each fuel discharge hole 22.
  • Each fuel discharge hole 22 opens on the surface of the fuel distribution plate 23 facing the anode 13.
  • Each fuel discharge hole 22 has a capillary force, and the peripheral length L of the perfect circle having the same cross-sectional area so that the liquid fuel can be stably discharged toward the anode 13 by the capillary force. It is formed by a hole having a cross-sectional shape larger than zero .
  • Examples of the cross-sectional shape that satisfies such conditions include a polygonal shape and a polygonal shape having a notch at one or a corner. Specifically, for example, a rectangular shape as shown in FIG. 3A (a square shape in the drawing), a cross shape as shown in FIG. 3B, a star shape as shown in FIG. Illustrated.
  • the cross-sectional shape of the fuel discharge hole 22 is a peripheral length L and a peripheral length L 0 of a perfect circle corresponding to the cross-sectional area.
  • the ratio (L / L 0 ) is preferably in the range of 1.0 to 1.4. If the ratio (L / L 0 ) is less than 1.0, the fuel supply to the anode 13 cannot be sufficiently stabilized. Conversely, even if the ratio (L / L 0 ) exceeds 1.4, the effect does not change much.
  • the cross-sectional area S of the fuel discharge hole 22 is preferably 0.5 mm 2 or less, more preferably 0.1 to 0.5 mm 2 .
  • the cross-sectional area S exceeds 0.5 mm 2 , the capillary force decreases and the fuel supply to the anode 13 cannot be sufficiently stabilized.
  • Each fuel discharge hole 22 does not necessarily have a uniform cross-sectional size and shape in the height direction.
  • the inner peripheral surface can be an inclined (tapered) surface whose cross-sectional size gradually increases toward the anode 13 side.
  • the inclination angle is preferably 8 ° or less.
  • the capillary force of the fuel discharge hole 22 is also affected by the wetting angle ⁇ between the inner peripheral surface of the fuel discharge hole 22 and the liquid fuel.
  • the wetting angle ⁇ is preferably 45 ° or less. When the wetting angle ⁇ exceeds 45 °, the capillary force decreases and the fuel supply to the anode 13 cannot be sufficiently stabilized.
  • the wetting angle ⁇ is more preferably 30 ° or less.
  • the wetting angle ⁇ can be adjusted by changing the material itself of the fuel distribution mechanism 3 (at least the portion constituting the fuel discharge hole 22), changing the glass transition temperature when the fuel distribution mechanism 3 is manufactured, or the like. If possible, the adjustment can also be made by subjecting the inner peripheral surface of the fuel discharge hole 22 to a hydrophilic treatment or a water repellent treatment.
  • a hydrophilic treatment method for example, plasma treatment, ozone treatment, flame treatment, laser treatment, electron beam irradiation, ion implantation, ion beam irradiation, or the like can be used.
  • a method of water repellency treatment for example, a method of coating with a fluorine-based resin such as polyvinylidene fluoride or polytetrafluoroethylene can be used.
  • a portion communicating with the narrow tube 25 below each fuel discharge hole 22 has a cross-sectional area as shown in FIG.
  • the liquid reservoir 26 in which the liquid fuel is temporarily stored is smaller than the area (in the case where the inner peripheral surface of the fuel discharge hole 22 is an inclined surface, the sectional area of the lowermost portion where the sectional area is minimized). Can be provided. By providing the liquid reservoir 26, the fuel supply to the anode 13 can be further stabilized.
  • the shape of the liquid reservoir 26 is not particularly limited as long as the cross-sectional area is smaller than the cross-sectional area of the fuel discharge hole 22.
  • the liquid reservoir 26 preferably has a cross-sectional area of 0.01 mm 2 or less as confirmed from the discharge port side.
  • the fuel released from the fuel distribution mechanism 3 is supplied to the anode 13 of the fuel cell 2 as described above.
  • the fuel diffuses through the anode gas diffusion layer 12 and is supplied to the anode catalyst layer 11.
  • an internal reforming reaction of methanol shown in the following formula (1) occurs in the anode catalyst layer 11.
  • pure methanol is used as the methanol fuel
  • the water produced in the cathode catalyst layer 14 and the water in the electrolyte membrane 17 are reacted with methanol to cause the internal reforming reaction of the formula (1).
  • the internal reforming reaction is caused by another reaction mechanism that does not require water.
  • Electrons (e ⁇ ) generated by this reaction are led to the outside via a current collector, and are led to the cathode 16 after operating a portable electronic device or the like as so-called electricity. Further, protons (H + ) generated by the internal reforming reaction of the formula (1) are guided to the cathode 16 through the electrolyte membrane 17. Air is supplied to the cathode 16 as an oxidant. Electrons (e ⁇ ) and protons (H + ) reaching the cathode 16 react with oxygen in the air in accordance with the following equation (2) in the cathode catalyst layer 14, and water is generated along with this reaction. 6e ⁇ + 6H + + (3/2) O 2 ⁇ 3H 2 O (2)
  • liquid fuel is stably discharged from the plurality of fuel discharge holes 22 opened on the surface of the fuel distribution plate 23 facing the anode 13. is important.
  • the fuel discharge hole 22 circumferential length L is formed by pores having a larger cross section than the circumferential length L 0 of the perfect circle of the ditto area.
  • Such a fuel discharge hole 22 can stably discharge liquid fuel toward the anode 13 only by capillary force. Therefore, the fuel supply to the fuel cell can be sufficiently stabilized without impairing the miniaturization of the fuel cell.
  • the wetting angle ⁇ of the inner peripheral surface with respect to the liquid fuel is 30 °
  • the fuel discharge holes 22 have various cross-sectional shapes as shown in Table 1.
  • the fuel cell 1 having the fuel distribution mechanism 3 formed with the above was manufactured.
  • the size of the fuel cell (MEA) 2 was 40 ⁇ 80 mm, and pure methanol was used as the liquid fuel.
  • a comparative example Comparative Examples 1 to 6
  • a fuel cell having the same configuration as that of the example was manufactured except that the fuel discharge hole 22 was changed to a fuel discharge hole having a cross-sectional shape as shown in Table 1.
  • the suction height of liquid fuel in the fuel discharge holes of these fuel cells was measured.
  • the measurement was performed by the following method. Using the same material as the fuel distribution mechanism 3, one fuel discharge hole is formed to produce a test fuel distribution mechanism. Supply pure methanol to the test fuel distribution mechanism without applying pressure, and measure from the side of the test fuel distribution mechanism to the maximum height of the liquid level from the end face of the liquid fuel pumped up after liquid fuel supply To do.
  • the test fuel distribution mechanism is sized so that the liquid level can be measured from the side.
  • the results are shown in Table 1.
  • the wicking height is shown as a ratio to the wicking height in Comparative Example 1.
  • the suction height reached the upper limit (1.18 as the suction height ratio), and no more measurement was possible, so “ ⁇ 1.18” was written.
  • Example 10 a fuel cell having the same configuration as that of Example 1 and Example 6 (Examples 9 and 6) except that a material having a wetting angle ⁇ of 80 ° with respect to the liquid fuel on the inner peripheral surface of the fuel discharge hole 22 was used.
  • Example 10 was prepared.
  • the suction height of the liquid fuel in the fuel discharge hole of the fuel cell was measured in the same manner as described above, and the ratio to the suction height in Comparative Example 1 was measured. Asked. The results are shown in Table 2.
  • Table 2 also shows the measurement results of the fuel cells of Example 1 and Example 6.
  • the fuel distribution mechanism 3 distributes the fuel to the plurality of fuel discharge holes 22 by the thin tubes 25 provided therein.
  • the liquid fuel flowing into the fuel distribution mechanism 3 from the fuel injection hole 21 can be evenly distributed to the plurality of fuel discharge holes 22 regardless of the direction and position. Can do.
  • the fuel injection hole 21 and the plurality of fuel discharge holes 22 are connected with the thin tube 25, it is possible to design such that more fuel is supplied to a specific portion of the fuel cell 1. For example, in the case where the heat dissipation by half of the fuel cell 1 is improved due to the convenience of mounting the device, a temperature distribution is conventionally generated, and a decrease in average output is inevitable.
  • the formation pattern of the thin tubes 25 and arranging the fuel discharge holes 22 densely in advance in a portion where heat dissipation is good heat generated by power generation in that portion can be increased. Thereby, the in-plane power generation degree can be made uniform, and it is possible to suppress a decrease in output.
  • the fuel distribution mechanism 3 in which the fuel injection holes 21 and the plurality of fuel discharge holes 22 are connected by the thin tubes 25 is excellent in achieving uniform fuel to the fuel cells.
  • the fuel distribution mechanism 3 may be configured to distribute to the plurality of fuel discharge holes 22 from the gap portion 27 provided therein.
  • the fuel distribution mechanism 3 shown in FIG. 5 has a fuel having at least one fuel injection hole 21 into which liquid fuel flows through the flow path 5 and a plurality of fuel discharge holes 22 through which the liquid fuel and its vaporized components are discharged.
  • a distribution plate 23A is provided inside the fuel distribution plate 23 ⁇ / b> A. Inside the fuel distribution plate 23 ⁇ / b> A, a gap 27 serving as a liquid fuel passage led from the fuel injection hole 21 is provided.
  • the plurality of fuel discharge holes 22 are respectively connected to gaps 27 that function as fuel passages.
  • the liquid fuel introduced into the fuel distribution mechanism 3 from the fuel injection hole 21 enters the gap 27 and is guided to the plurality of fuel discharge holes 22 through the gap 27 that functions as the fuel passage.
  • a porous body 28 can be inserted between the fuel distribution mechanism 3 and the anode 13 as shown in FIG.
  • FIG. 6 shows an example in which the porous body 28 is used in the fuel cell 1 shown in FIG.
  • Various resins are used as the constituent material of the porous body 28, and a porous resin film or the like is used as the porous body 28.
  • the amount of fuel supplied to the anode 13 can be further averaged. That is, the liquid fuel discharged from the fuel discharge hole 22 of the fuel distribution mechanism 3 is once absorbed by the porous body 28 and diffuses in the in-plane direction inside the porous body 28. Thereafter, fuel is supplied from the porous body 28 to the anode 13, so that the fuel supply amount can be further averaged.
  • the porous body 28 may be arranged by laminating a plurality of porous films.
  • the mechanism for sending the liquid fuel from the fuel storage unit 14 to the fuel distribution mechanism 3 is not particularly limited.
  • the liquid fuel can be dropped from the fuel storage unit 4 to the fuel distribution mechanism 3 and fed using gravity.
  • the flow path 5 filled with a porous body or the like the liquid can be fed from the fuel storage portion 4 to the fuel distribution mechanism 3 by a capillary phenomenon.
  • the fuel storage part 4 can be pressurized and the liquid fuel can be sent from the fuel storage part 4 to the fuel distribution mechanism 3 by the pressure.
  • the liquid feeding from the fuel storage unit 4 to the fuel distribution mechanism 3 may be performed by a pump inserted in the flow path 5.
  • This pump is used only for the purpose of sending liquid fuel from the fuel storage portion 4 to the fuel distribution mechanism 3.
  • the type of pump is not particularly limited, but from the viewpoint that a small amount of liquid fuel can be sent with good controllability, and that further reduction in size and weight is possible, rotary vane pumps, electroosmotic flow pumps, diaphragm pumps, ironing irons. It is preferable to use a pump or the like.
  • a rotary vane pump feeds liquid by rotating a wing with a motor.
  • the electroosmotic flow pump uses a sintered porous material such as silica that causes an electroosmotic flow phenomenon.
  • the diaphragm pump is a pump that feeds liquid by driving the diaphragm with an electromagnet or piezoelectric ceramics.
  • the squeezing pump presses a part of the flexible fuel flow path and squeezes the fuel.
  • the fuel cell 1 of the above-described embodiment is effective when various liquid fuels are used, and the type and concentration of the liquid fuel are not limited.
  • the characteristics of the fuel distribution mechanism 3 having a plurality of fuel discharge holes 22 become more apparent when the fuel concentration is high.
  • the fuel cell 1 of the above embodiment can particularly exhibit its performance and effects when methanol having a concentration of 80% or more is used as the liquid fuel. Therefore, the above embodiment has a concentration of 80%. It is preferable to apply to the fuel cell using the above methanol as a liquid fuel.
  • the present invention can be applied to various fuel cells using liquid fuel. Further, the specific configuration of the fuel cell, the supply state of the fuel, and the like are not particularly limited. The present invention can be applied to various forms such as liquid fuel vapor supplied to the MEA, liquid fuel vapor, all liquid fuel, or liquid fuel vapor supplied partially in a liquid state.
  • the constituent elements can be modified and embodied without departing from the technical idea of the present invention. Furthermore, various modifications are possible, such as appropriately combining a plurality of constituent elements shown in the above embodiments, or deleting some constituent elements from all the constituent elements shown in the embodiments.
  • Embodiments of the present invention can be expanded or modified within the scope of the technical idea of the present invention, and these expanded and modified embodiments are also included in the technical scope of the present invention.
  • SYMBOLS 1 ... Fuel cell, 2 ... Fuel cell (MEA), 3 ... Fuel distribution mechanism, 4 ... Fuel accommodating part, 5 ... Flow path, 11 ... Anode catalyst layer, 12 ... Anode gas diffusion layer, 13 ... Anode (fuel electrode) ), 14 ... Cathode catalyst layer, 15 ... Cathode gas diffusion layer, 16 ... Cathode (air electrode), 17 ... Electrolyte membrane, 21 ... Fuel injection hole, 22 ... Fuel discharge hole, 23, 23A ... Fuel distribution plate, 25 ... Narrow tube, 26... Liquid reservoir, 27.

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Abstract

Disclosed is a fuel battery using a liquid fuel, wherein supply of a fuel to a fuel battery cell is stabilized. A fuel battery (1) is comprised of a membrane electrode connection element (2) provided with a fuel electrode (13), an air electrode (16), and an electrolyte membrane (17) provided between and held by the electrodes. Fuel is supplied from a fuel distributing mechanism (3) connected to a fuel tank (4) via a passage (5), to the membrane electrode connection element (2). The fuel distributing mechanism (3) is provided with a plurality of fuel discharging holes (22). Each of the fuel discharging holes (22) has a cross sectional shape, the circumferential length (L) of which is larger than the circumferential length (L0) of a true circle that has an area that is equal to the cross sectional area (S) of each fuel discharging hole.

Description

燃料電池Fuel cell
　本発明は、液体燃料を用いた燃料電池に関する。 The present invention relates to a fuel cell using liquid fuel.
　近年、ノートパソコンや携帯電話等の各種携帯用電子機器を長時間充電なしで使用可能とするために、これら携帯用電子機器の電源に燃料電池を用いる試みがなされている。燃料電池は燃料と空気を供給するだけで発電することができ、燃料を補給すれば連続して長時間発電することが可能であるという特徴を有している。このため、燃料電池を小型化できれば、携帯用電子機器の電源として極めて有利なシステムといえる。 In recent years, attempts have been made to use a fuel cell as a power source for portable electronic devices such as notebook computers and mobile phones so that they can be used without charging for a long time. A fuel cell is characterized in that it can generate electric power simply by supplying fuel and air, and can generate electric power continuously for a long time if fuel is replenished. For this reason, if the fuel cell can be reduced in size, it can be said that the system is extremely advantageous as a power source for portable electronic devices.
　直接メタノール型燃料電池（ＤＭＦＣ）は小型化が可能であり、さらに燃料の取り扱いも容易であるため、携帯用電子機器の電源として有望視されている。ＤＭＦＣにおける液体燃料の供給方式としては、気体供給型や液体供給型等のアクティブ方式、また燃料収容部内の液体燃料を電池内部で気化させて燃料極に供給する内部気化型等のパッシブ方式が知られている。 Direct methanol fuel cells (DMFC) are promising as power sources for portable electronic devices because they can be miniaturized and the fuel can be easily handled. As the liquid fuel supply method in the DMFC, there are known an active method such as a gas supply type and a liquid supply type, and a passive method such as an internal vaporization type in which the liquid fuel in the fuel container is vaporized inside the cell and supplied to the fuel electrode. It has been.
　これらのうち、内部気化型等のパッシブ方式はＤＭＦＣの小型化に対して特に有利である。パッシブ型ＤＭＦＣにおいては、例えば燃料極、電解質膜および空気極を有する膜電極接合体（燃料電池セル）を、樹脂製の箱状容器からなる燃料収容部上に配置した構造が提案されている（例えば、特許文献１参照。）。燃料収容部から気化した燃料を直接燃料電池セルに供給する場合、燃料電池の出力の制御性を高めることが重要となるが、現状のパッシブ型ＤＭＦＣでは必ずしも十分な出力制御性は得られていない。 Among these, passive methods such as an internal vaporization type are particularly advantageous for downsizing of the DMFC. In the passive DMFC, for example, a structure is proposed in which a membrane electrode assembly (fuel cell) having a fuel electrode, an electrolyte membrane, and an air electrode is disposed on a fuel containing portion made of a resin box-like container ( For example, see Patent Document 1.) When the fuel vaporized from the fuel container is directly supplied to the fuel cell, it is important to improve the output controllability of the fuel cell, but the current passive DMFC does not always have sufficient output controllability. .
　一方、ＤＭＦＣの燃料電池セルと燃料収容部とを流路を介して接続することが検討されている（例えば、特許文献２参照。）。燃料収容部から供給された液体燃料を燃料電池セルに流路を介して供給することによって、流路の形状や径等に基づいて液体燃料の供給量を調整することができる。但し、流路からの液体燃料の供給構造によっては、燃料電池セルに対する燃料の供給が十分かつ安定に行われないおそれがある。 On the other hand, it has been studied to connect a DMFC fuel cell and a fuel container through a flow path (for example, see Patent Document 2). By supplying the liquid fuel supplied from the fuel storage unit to the fuel cell via the flow path, the supply amount of the liquid fuel can be adjusted based on the shape and diameter of the flow path. However, depending on the supply structure of the liquid fuel from the flow path, there is a possibility that the fuel supply to the fuel cell is not sufficiently and stably performed.
　燃料電池セルへの燃料の供給状態を改善する技術として、例えば特許文献３に、燃料供給流路表面を親水化することにより、その毛管力を高めることが記載されている。しかし、親水化処理するだけでは燃料の供給を十分に安定化させることはできない。 As a technique for improving the supply state of fuel to a fuel battery cell, for example, Patent Document 3 describes increasing the capillary force by hydrophilizing the surface of a fuel supply channel. However, the fuel supply cannot be sufficiently stabilized only by hydrophilization treatment.
国際公開第２００５／１１２１７２号パンフレットInternational Publication No. 2005/112172 Pamphlet 特表２００５－５１８６４６公報JP 2005-518646 Gazette 特開２００７－２１４０５５公報JP 2007-214055 A
　本発明は、燃料電池の小型化等を損なうことなく、燃料電池セルへの燃料の供給を十分に安定化することができる燃料電池を提供することを目的とする。 It is an object of the present invention to provide a fuel cell that can sufficiently stabilize the supply of fuel to the fuel cell without impairing the miniaturization of the fuel cell.
　本発明の一態様に係る燃料電池は、燃料極と、空気極と、前記燃料極と前記空気極とに挟持された電解質膜とを有する膜電極接合体と、前記膜電極接合体の前記燃料極側に配置され、前記燃料極の複数個所に対して燃料を分配供給する複数の燃料排出孔を有する燃料分配機構と、液体燃料を収容すると共に、前記燃料分配機構と流路を介して接続された燃料収容部とを具備し、前記燃料分配機構の各燃料排出孔は、周長Ｌが同断面積Ｓの真円の周長Ｌ０より大きい断面形状を有することを特徴としている。 A fuel cell according to an aspect of the present invention includes a membrane electrode assembly including a fuel electrode, an air electrode, and an electrolyte membrane sandwiched between the fuel electrode and the air electrode, and the fuel of the membrane electrode assembly. A fuel distribution mechanism that is disposed on the pole side and has a plurality of fuel discharge holes that distribute and supply fuel to a plurality of locations of the fuel electrode, and accommodates liquid fuel and is connected to the fuel distribution mechanism via a flow path comprising a fuel receiving portion is, the fuel discharge hole of the fuel distribution mechanism, the circumferential length L is characterized by having a circumferential length L 0 greater than the cross-sectional shape of a true circle ditto area S.
　本発明の一態様に係る燃料電池によれば、周長Ｌが同断面積Ｓの真円の周長Ｌ０より大きい断面形状を有する燃料排出孔から燃料極に対して燃料が供給されるため、燃料電池の小型化等を損なうことなく、燃料の燃料電池セルへの供給を十分に安定化することができる。 According to the fuel cell according to an embodiment of the present invention, since the circumferential length L is the fuel is supplied to the fuel electrode from the fuel discharge hole having a circumferential length L 0 greater than the cross-sectional shape of a true circle ditto area S, The supply of fuel to the fuel cell can be sufficiently stabilized without impairing the miniaturization of the fuel cell.
本発明の一実施形態による燃料電池の構成を示す断面図である。It is sectional drawing which shows the structure of the fuel cell by one Embodiment of this invention. 図１に示す燃料電池で使用した燃料分配機構の内部構造を透視して示す平面図である。FIG. 2 is a plan view showing the internal structure of a fuel distribution mechanism used in the fuel cell shown in FIG. 図１に示す燃料電池で使用した燃料分配機構の燃料排出孔の断面形状例を示す平面図である。It is a top view which shows the cross-sectional example of the fuel discharge hole of the fuel distribution mechanism used with the fuel cell shown in FIG. 図１に示す燃料電池で使用した燃料分配機構の要部を拡大して示す（ａ）断面図および（ｂ）平面図である。It is (a) sectional drawing and (b) top view which expand and show the principal part of the fuel distribution mechanism used with the fuel cell shown in FIG. 図１に示す燃料電池の一変形例を示す断面図である。It is sectional drawing which shows the modification of the fuel cell shown in FIG. 図１に示す燃料電池の他の変形例を示す断面図である。FIG. 7 is a cross-sectional view showing another modification of the fuel cell shown in FIG. 1.
　以下、本発明を実施するための形態について、図面を参照して説明する。図１は本発明の一実施形態による燃料電池の構成を示す断面図である。図１に示す燃料電池１は、起電部を構成する燃料電池セル２と、この燃料電池セル２に燃料を供給する燃料分配機構３と、液体燃料を収容する燃料収容部４と、これら燃料分配機構３と燃料収容部４とを接続する流路５とから主として構成されている。 Hereinafter, modes for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration of a fuel cell according to an embodiment of the present invention. A fuel cell 1 shown in FIG. 1 includes a fuel cell 2 constituting an electromotive unit, a fuel distribution mechanism 3 that supplies fuel to the fuel cell 2, a fuel storage unit 4 that stores liquid fuel, and these fuels. It is mainly composed of a flow path 5 that connects the distribution mechanism 3 and the fuel storage portion 4.
　燃料電池セル２は、アノード触媒層１１とアノードガス拡散層１２とを有するアノード（燃料極）１３と、カソード触媒層１４とカソードガス拡散層１５とを有するカソード（空気極／酸化剤極）１６と、アノード触媒層１１とカソード触媒層１４とで挟持されたプロトン（水素イオン）伝導性の電解質膜１７とから構成される膜電極接合体（ＭＥＡ）を有している。 The fuel cell 2 includes an anode (fuel electrode) 13 having an anode catalyst layer 11 and an anode gas diffusion layer 12, and a cathode (air electrode / oxidant electrode) 16 having a cathode catalyst layer 14 and a cathode gas diffusion layer 15. And a membrane electrode assembly (MEA) composed of a proton (hydrogen ion) conductive electrolyte membrane 17 sandwiched between the anode catalyst layer 11 and the cathode catalyst layer 14.
　アノード触媒層１１やカソード触媒層１４に含有される触媒としては、例えばＰｔ、Ｒｕ、Ｒｈ、Ｉｒ、Ｏｓ、Ｐｄ等の白金族元素の単体、白金族元素を含有する合金等が挙げられる。アノード触媒層１１にはメタノールや一酸化炭素等に対して強い耐性を有するＰｔ－ＲｕやＰｔ－Ｍｏ等を用いることが好ましい。カソード触媒層１４にはＰｔやＰｔ－Ｎｉ等を用いることが好ましい。触媒はこれらに限定されるものではなく、触媒活性を有する各種の物質を使用することができる。触媒は炭素材料のような導電性担持体を使用した担持触媒、あるいは無担持触媒のいずれであってもよい。 Examples of the catalyst contained in the anode catalyst layer 11 and the cathode catalyst layer 14 include a simple substance of a platinum group element such as Pt, Ru, Rh, Ir, Os, and Pd, an alloy containing the platinum group element, and the like. The anode catalyst layer 11 is preferably made of Pt—Ru, Pt—Mo, or the like that has strong resistance to methanol, carbon monoxide, or the like. Pt, Pt—Ni or the like is preferably used for the cathode catalyst layer 14. The catalyst is not limited to these, and various substances having catalytic activity can be used. The catalyst may be either a supported catalyst using a conductive support such as a carbon material or an unsupported catalyst.
　電解質膜１７を構成するプロトン伝導性材料としては、例えばスルホン酸基を有するパーフルオロスルホン酸重合体のようなフッ素系樹脂（ナフィオン（商品名、デュポン社製）やフレミオン（商品名、旭硝子社製）等）、スルホン酸基を有する炭化水素系樹脂等の有機系材料、あるいはタングステン酸やリンタングステン酸等の無機系材料が挙げられる。プロトン伝導性の電解質膜１７はこれらに限られるものではない。 Examples of the proton conductive material constituting the electrolyte membrane 17 include fluorine-based resins (Nafion (trade name, manufactured by DuPont) and Flemion (trade name, manufactured by Asahi Glass Co., Ltd.) such as a perfluorosulfonic acid polymer having a sulfonic acid group. Etc.), organic materials such as hydrocarbon resins having sulfonic acid groups, or inorganic materials such as tungstic acid and phosphotungstic acid. The proton conductive electrolyte membrane 17 is not limited to these.
　アノード触媒層１１に積層されるアノードガス拡散層１２は、アノード触媒層１１に燃料を均一に供給する役割を果たすと同時に、アノード触媒層１１の集電体も兼ねている。カソード触媒層１４に積層されるカソードガス拡散層１５は、カソード触媒層１４に酸化剤を均一に供給する役割を果たすと同時に、カソード触媒層１４の集電体も兼ねている。アノードガス拡散層１２およびカソードガス拡散層１５は多孔質基材で構成されている。 The anode gas diffusion layer 12 laminated on the anode catalyst layer 11 serves to uniformly supply fuel to the anode catalyst layer 11 and also serves as a current collector for the anode catalyst layer 11. The cathode gas diffusion layer 15 laminated on the cathode catalyst layer 14 serves to uniformly supply the oxidant to the cathode catalyst layer 14 and also serves as a current collector for the cathode catalyst layer 14. The anode gas diffusion layer 12 and the cathode gas diffusion layer 15 are made of a porous substrate.
　アノードガス拡散層１２およびカソードガス拡散層１５には、必要に応じて導電層（図示なし）が積層される。これらの導電層としては、例えばＡｕ、Ｎｉのような導電性金属材料からなる多孔質層（例えばメッシュ）または箔体、多孔質膜、薄膜、あるいはステンレス鋼（ＳＵＳ）等の導電性金属材料にＡｕ等の良導電性金属を被覆した複合材等が用いられる。 A conductive layer (not shown) is laminated on the anode gas diffusion layer 12 and the cathode gas diffusion layer 15 as necessary. As these conductive layers, for example, a porous layer (for example, a mesh) or a foil body, a porous film, a thin film, or a conductive metal material such as stainless steel (SUS) made of a conductive metal material such as Au or Ni. A composite material coated with a highly conductive metal such as Au is used.
　燃料電池セル（ＭＥＡ）２上にはカバープレート１８が積層され、このカバープレート１８と電解質膜１７との間、および電解質膜１７と燃料分配機構３との間には、それぞれゴム製のＯリング１９が介在されている。Ｏリング１９によって燃料電池セル（ＭＥＡ）２からの燃料漏れや酸化剤漏れが防止される。 A cover plate 18 is laminated on the fuel cell (MEA) 2, and a rubber O-ring is provided between the cover plate 18 and the electrolyte membrane 17 and between the electrolyte membrane 17 and the fuel distribution mechanism 3. 19 is interposed. O-ring 19 prevents fuel leakage and oxidant leakage from the fuel cell (MEA) 2.
　図示を省略したが、カバープレート１８は酸化剤である空気を取入れるための開口を有している。カバープレート１８とカソード１６との間には、必要に応じて保湿層や表面層が配置される。保湿層はカソード触媒層１４で生成された水の一部が含浸されて、水の蒸散を抑制すると共に、カソード触媒層１４への空気の均一拡散を促進するものである。表面層は空気の取入れ量を調整するものであり、空気の取入れ量に応じて個数や大きさ等が調整された複数の空気導入口を有している。 Although not shown, the cover plate 18 has an opening for taking in air as an oxidant. A moisture retaining layer and a surface layer are disposed between the cover plate 18 and the cathode 16 as necessary. The moisturizing layer is impregnated with a part of the water generated in the cathode catalyst layer 14 to suppress the transpiration of water and promote uniform diffusion of air to the cathode catalyst layer 14. The surface layer adjusts the amount of air taken in, and has a plurality of air inlets whose number, size, etc. are adjusted according to the amount of air taken in.
　燃料収容部４には、燃料電池セル２に対応した液体燃料が収容されている。液体燃料としては、各種濃度のメタノール水溶液や純メタノール等のメタノール燃料が挙げられる。液体燃料はメタノール燃料に限られるものではない。液体燃料は、例えばエタノール水溶液や純エタノール等のエタノール燃料、プロパノール水溶液や純プロパノール等のプロパノール燃料、グリコール水溶液や純グリコール等のグリコール燃料、ジメチルエーテル、ギ酸、その他の液体燃料であってもよい。燃料収容部４には燃料電池セル２に応じた液体燃料が収容される。 The fuel storage unit 4 stores liquid fuel corresponding to the fuel battery cell 2. Examples of the liquid fuel include methanol fuels such as aqueous methanol solutions of various concentrations and pure methanol. The liquid fuel is not limited to methanol fuel. The liquid fuel may be, for example, an ethanol fuel such as an ethanol aqueous solution or pure ethanol, a propanol fuel such as a propanol aqueous solution or pure propanol, a glycol fuel such as a glycol aqueous solution or pure glycol, dimethyl ether, formic acid, or other liquid fuel. Liquid fuel corresponding to the fuel cells 2 is stored in the fuel storage unit 4.
　燃料電池セル２のアノード１３側には、燃料分配機構３が配置されている。燃料分配機構３は配管のような液体燃料の流路５を介して燃料収容部４と接続されている。燃料分配機構３には燃料収容部４から流路５を介して液体燃料が導入される。流路５は燃料分配機構３や燃料収容部４と独立した配管に限られるものではない。例えば、燃料分配機構３と燃料収容部４とを積層して一体化する場合、これらを繋ぐ液体燃料の流路であってもよい。燃料分配機構３は流路５を介して燃料収容部４と接続されていればよい。 A fuel distribution mechanism 3 is arranged on the anode 13 side of the fuel battery cell 2. The fuel distribution mechanism 3 is connected to the fuel storage portion 4 through a liquid fuel flow path 5 such as a pipe. Liquid fuel is introduced into the fuel distribution mechanism 3 from the fuel storage portion 4 through the flow path 5. The flow path 5 is not limited to piping independent of the fuel distribution mechanism 3 and the fuel storage unit 4. For example, when the fuel distribution mechanism 3 and the fuel storage unit 4 are stacked and integrated, a liquid fuel flow path connecting them may be used. The fuel distribution mechanism 3 only needs to be connected to the fuel storage portion 4 via the flow path 5.
　燃料分配機構３は、液体燃料が流路５を介して流入する少なくとも１個の燃料注入孔２１と、液体燃料やその気化成分を排出する複数の燃料排出孔２２とを有する燃料分配板２３を備えている。燃料分配板２３を形成する材料としては、液体燃料が浸透せず、かつ液体燃料に侵食されない材料であれば、特に限定されず、種々の材料を使用することができる。具体的には、例えば樹脂、炭素材料、金属などが挙げられる。 The fuel distribution mechanism 3 includes a fuel distribution plate 23 having at least one fuel injection hole 21 through which liquid fuel flows through the flow path 5 and a plurality of fuel discharge holes 22 through which liquid fuel and vaporized components thereof are discharged. I have. The material for forming the fuel distribution plate 23 is not particularly limited as long as the liquid fuel does not permeate and is not eroded by the liquid fuel, and various materials can be used. Specifically, for example, resin, carbon material, metal and the like can be mentioned.
　燃料分配板２３の内部には、図２に示すように、液体燃料の通路として機能する細管２５が設けられている。細管２５は燃料極の面方向に枝状に伸びており、その一端（始端部）は燃料注入孔２１に接続されている。細管２５は、途中で複数に分岐しており、これら分岐した細管２５の各終端部に燃料排出孔２２がそれぞれ設けられている。燃料排出孔２２の個数は２個以上であればよいが、燃料電池セル２の面内における燃料供給量を均一化する上で、０．１～１０個／ｃｍ２の燃料排出孔２２が存在するように形成することが好ましい。燃料排出孔２２の個数が０．１個／ｃｍ２未満であると、燃料電池セル２に対する燃料供給量を十分に均一化することができない。燃料排出孔３２の個数を１０個／ｃｍ２を超えて形成しても、それ以上の効果が得られない。また、細管２５は例えば内径が０．０５～５ｍｍの貫通孔であることが好ましい。 As shown in FIG. 2, a thin tube 25 that functions as a liquid fuel passage is provided inside the fuel distribution plate 23. The narrow tube 25 extends in a branch shape in the surface direction of the fuel electrode, and one end (starting end portion) thereof is connected to the fuel injection hole 21. The thin tubes 25 are branched into a plurality of portions along the way, and fuel discharge holes 22 are provided at the end portions of the branched thin tubes 25, respectively. The number of the fuel discharge holes 22 may be two or more. However, in order to equalize the fuel supply amount in the surface of the fuel cell 2, there are 0.1 to 10 / cm 2 fuel discharge holes 22. It is preferable to form so as to. If the number of the fuel discharge holes 22 is less than 0.1 / cm 2 , the amount of fuel supplied to the fuel cells 2 cannot be made sufficiently uniform. Even if the number of the fuel discharge holes 32 exceeds 10 / cm 2 , no further effect can be obtained. The thin tube 25 is preferably a through hole having an inner diameter of 0.05 to 5 mm, for example.
　燃料注入孔２１から燃料分配機構３に導入された液体燃料は、燃料通路として機能する細管２５を介して複数の燃料排出孔２２にそれぞれ導かれ、アノード１３の複数個所に向けて排出される。燃料分配機構３とアノード１３との間に、例えば液体燃料の気化成分のみを透過し、液体成分は透過させない気液分離体（図示せず）を配置してもよい。これによって、燃料電池セル２のアノード１３に液体燃料の気化成分が供給される。気液分離体は、各燃料排出孔２２に配置してもよい。 The liquid fuel introduced into the fuel distribution mechanism 3 from the fuel injection hole 21 is led to the plurality of fuel discharge holes 22 through the thin tubes 25 functioning as fuel passages, and discharged toward a plurality of locations of the anode 13. Between the fuel distribution mechanism 3 and the anode 13, for example, a gas-liquid separator (not shown) that transmits only the vaporized component of the liquid fuel and does not transmit the liquid component may be disposed. As a result, the vaporized component of the liquid fuel is supplied to the anode 13 of the fuel cell 2. The gas-liquid separator may be disposed in each fuel discharge hole 22.
　各燃料排出孔２２は、燃料分配板２３のアノード１３と対向する面に開口している。各燃料排出孔２２は、毛管力を有し、かつその毛管力で液体燃料をアノード１３に向けて安定して排出することができるように、周長Ｌが同断面積の真円の周長Ｌ０より大きくなる断面形状を有する孔で形成されている。このような条件を満足する断面形状としては、例えば多角形状、片部または角部に切欠き部を持つ多角形状などが挙げられる。具体的には、例えば図３（ａ）に示すような矩形状（図面は、正方形状）、図３（ｂ）に示すような十字状、図３（ｃ）に示すような星形状などが例示される。 Each fuel discharge hole 22 opens on the surface of the fuel distribution plate 23 facing the anode 13. Each fuel discharge hole 22 has a capillary force, and the peripheral length L of the perfect circle having the same cross-sectional area so that the liquid fuel can be stably discharged toward the anode 13 by the capillary force. It is formed by a hole having a cross-sectional shape larger than zero . Examples of the cross-sectional shape that satisfies such conditions include a polygonal shape and a polygonal shape having a notch at one or a corner. Specifically, for example, a rectangular shape as shown in FIG. 3A (a square shape in the drawing), a cross shape as shown in FIG. 3B, a star shape as shown in FIG. Illustrated.
　燃料排出孔２２の毛管力を高め、アノード１３に対する燃料供給の安定化を図る上で、燃料排出孔２２の断面形状は、その周長Ｌとその断面積に該当する真円の周長Ｌ０との比（Ｌ／Ｌ０）が１．０～１．４の範囲にある形状であることが好ましい。比（Ｌ／Ｌ０）が１．０未満であると、アノード１３への燃料供給を十分に安定化することができない。逆に、比（Ｌ／Ｌ０）が１．４を超えても、効果はあまり変わらない。 In order to increase the capillary force of the fuel discharge hole 22 and stabilize the fuel supply to the anode 13, the cross-sectional shape of the fuel discharge hole 22 is a peripheral length L and a peripheral length L 0 of a perfect circle corresponding to the cross-sectional area. The ratio (L / L 0 ) is preferably in the range of 1.0 to 1.4. If the ratio (L / L 0 ) is less than 1.0, the fuel supply to the anode 13 cannot be sufficiently stabilized. Conversely, even if the ratio (L / L 0 ) exceeds 1.4, the effect does not change much.
　また、燃料排出孔２２の断面積Ｓは、０．５ｍｍ２以下であることが好ましく、０．１～０．５ｍｍ２であることがより好ましい。断面積Ｓが０．５ｍｍ２を超えると、毛管力が低下し、アノード１３への燃料供給を十分に安定化することができない。 The cross-sectional area S of the fuel discharge hole 22 is preferably 0.5 mm 2 or less, more preferably 0.1 to 0.5 mm 2 . When the cross-sectional area S exceeds 0.5 mm 2 , the capillary force decreases and the fuel supply to the anode 13 cannot be sufficiently stabilized.
　各燃料排出孔２２は、その断面の大きさおよび形状が高さ方向に必ずしも均一である必要はない。例えば、内周面を、断面の大きさがアノード１３側に向かって徐々に拡大するような傾斜（テーパ）面とすることも可能である。但し、傾斜（テーパ）角があまり大きくなると、毛管力が低下し、アノード１３への燃料供給を十分に安定化することができなくなるおそれがある。傾斜角は８°以下であることが好ましい。 Each fuel discharge hole 22 does not necessarily have a uniform cross-sectional size and shape in the height direction. For example, the inner peripheral surface can be an inclined (tapered) surface whose cross-sectional size gradually increases toward the anode 13 side. However, if the inclination (taper) angle becomes too large, the capillary force decreases, and there is a possibility that the fuel supply to the anode 13 cannot be sufficiently stabilized. The inclination angle is preferably 8 ° or less.
　燃料排出孔２２の毛管力は、燃料排出孔２２の内周面と液体燃料との濡れ角θによっても影響を受ける。毛管力を高め、アノード１３に対する燃料供給の安定化を図る上で、濡れ角θは、４５°以下であることが好ましい。濡れ角θが４５°を超えると、毛管力が低下し、アノード１３への燃料供給を十分に安定化することができない。この濡れ角θは３０°以下であることがより好ましい。 The capillary force of the fuel discharge hole 22 is also affected by the wetting angle θ between the inner peripheral surface of the fuel discharge hole 22 and the liquid fuel. In order to increase the capillary force and stabilize the fuel supply to the anode 13, the wetting angle θ is preferably 45 ° or less. When the wetting angle θ exceeds 45 °, the capillary force decreases and the fuel supply to the anode 13 cannot be sufficiently stabilized. The wetting angle θ is more preferably 30 ° or less.
　濡れ角θは、燃料分配機構３（少なくとも燃料排出孔２２を構成する部分）の材料そのものの変更、燃料分配機構３の製造時のガラス転移温度の変更等で調整することができる。また、可能であれば燃料排出孔２２の内周面に親水化処理または撥水化処理を施すことによっても調整することができる。親水化処理の方法としては、例えばプラズマ処理、オゾン処理、フレーム処理、レーザ処理、電子線の照射、イオン注入、イオンビームの照射などを用いることができる。また、撥水化処理の方法としては、例えばポリフッ化ビニリデン、ポリテトラフルオリエチレンなどのフッ素系樹脂でコーティングする方法を用いることができる。 The wetting angle θ can be adjusted by changing the material itself of the fuel distribution mechanism 3 (at least the portion constituting the fuel discharge hole 22), changing the glass transition temperature when the fuel distribution mechanism 3 is manufactured, or the like. If possible, the adjustment can also be made by subjecting the inner peripheral surface of the fuel discharge hole 22 to a hydrophilic treatment or a water repellent treatment. As a hydrophilic treatment method, for example, plasma treatment, ozone treatment, flame treatment, laser treatment, electron beam irradiation, ion implantation, ion beam irradiation, or the like can be used. Moreover, as a method of water repellency treatment, for example, a method of coating with a fluorine-based resin such as polyvinylidene fluoride or polytetrafluoroethylene can be used.
　各燃料排出孔２２の下方、細管２５に連通する部分に、図４（ａ）の断面図、その平面図である図４（ｂ）に示すように、断面積が各燃料排出孔２２の断面積（燃料排出孔２２の内周面が傾斜面からなる場合は、その断面積が最小となる最下部の断面積）より小さく、それ故液体燃料が一時的に貯留される液溜部２６を設けることができる。液溜部２６を設けることにより、アノード１３に対する燃料供給をより安定化することが可能になる。液溜部２６は、断面積が燃料排出孔２２の断面積より小さければ、その形状などは特に限定されない。液溜部２６は、例えば、排出口側から確認した断面積が０．０１ｍｍ２以下であることが好ましい。 A portion communicating with the narrow tube 25 below each fuel discharge hole 22 has a cross-sectional area as shown in FIG. The liquid reservoir 26 in which the liquid fuel is temporarily stored is smaller than the area (in the case where the inner peripheral surface of the fuel discharge hole 22 is an inclined surface, the sectional area of the lowermost portion where the sectional area is minimized). Can be provided. By providing the liquid reservoir 26, the fuel supply to the anode 13 can be further stabilized. The shape of the liquid reservoir 26 is not particularly limited as long as the cross-sectional area is smaller than the cross-sectional area of the fuel discharge hole 22. For example, the liquid reservoir 26 preferably has a cross-sectional area of 0.01 mm 2 or less as confirmed from the discharge port side.
　燃料分配機構３から放出された燃料は、上述したように燃料電池セル２のアノード１３に供給される。燃料電池セル２内において、燃料はアノードガス拡散層１２を拡散してアノード触媒層１１に供給される。液体燃料としてメタノール燃料を用いた場合、アノード触媒層１１で下記（１）式に示すメタノールの内部改質反応が生じる。メタノール燃料として純メタノールを使用した場合には、カソード触媒層１４で生成した水や電解質膜１７中の水をメタノールと反応させて（１）式の内部改質反応を生起させる。あるいは、水を必要としない他の反応機構により内部改質反応を生じさせる。
　　ＣＨ３ＯＨ＋Ｈ２Ｏ　→　ＣＯ２＋６Ｈ＋＋６ｅ－　…（１） The fuel released from the fuel distribution mechanism 3 is supplied to the anode 13 of the fuel cell 2 as described above. In the fuel cell 2, the fuel diffuses through the anode gas diffusion layer 12 and is supplied to the anode catalyst layer 11. When methanol fuel is used as the liquid fuel, an internal reforming reaction of methanol shown in the following formula (1) occurs in the anode catalyst layer 11. When pure methanol is used as the methanol fuel, the water produced in the cathode catalyst layer 14 and the water in the electrolyte membrane 17 are reacted with methanol to cause the internal reforming reaction of the formula (1). Alternatively, the internal reforming reaction is caused by another reaction mechanism that does not require water.
CH 3 OH + H 2 O → CO 2 + 6H + + 6e − (1)
　この反応で生成した電子（ｅ－）は集電体を経由して外部に導かれ、いわゆる電気として携帯用電子機器等を動作させた後、カソード１６に導かれる。また、（１）式の内部改質反応で生成したプロトン（Ｈ＋）は電解質膜１７を経てカソード１６に導かれる。カソード１６には酸化剤として空気が供給される。カソード１６に到達した電子（ｅ－）とプロトン（Ｈ＋）は、カソード触媒層１４で空気中の酸素と下記（２）式にしたがって反応し、この反応に伴って水が生成する。
　　６ｅ－＋６Ｈ＋＋（３／２）Ｏ２　→　３Ｈ２Ｏ　…（２） Electrons (e − ) generated by this reaction are led to the outside via a current collector, and are led to the cathode 16 after operating a portable electronic device or the like as so-called electricity. Further, protons (H + ) generated by the internal reforming reaction of the formula (1) are guided to the cathode 16 through the electrolyte membrane 17. Air is supplied to the cathode 16 as an oxidant. Electrons (e − ) and protons (H + ) reaching the cathode 16 react with oxygen in the air in accordance with the following equation (2) in the cathode catalyst layer 14, and water is generated along with this reaction.
6e − + 6H + + (3/2) O 2 → 3H 2 O (2)
　上述した燃料電池１の発電反応を安定して生起させるためには、燃料分配板２３のアノード１３と対向する面に開口させた複数の燃料排出孔２２から、液体燃料を安定して排出させることが重要である。本実施形態においては、上述したように、燃料排出孔２２を周長Ｌが同断面積の真円の周長Ｌ０より大きくなる断面形状を有する孔で形成している。このような燃料排出孔２２は、毛管力のみで液体燃料をアノード１３に向けて安定して排出することができる。したがって、燃料電池の小型化等を損なうことなく、燃料電池セルへの燃料の供給を十分に安定化することができる。 In order to stably generate the power generation reaction of the fuel cell 1 described above, liquid fuel is stably discharged from the plurality of fuel discharge holes 22 opened on the surface of the fuel distribution plate 23 facing the anode 13. is important. In this embodiment, as described above, the fuel discharge hole 22 circumferential length L is formed by pores having a larger cross section than the circumferential length L 0 of the perfect circle of the ditto area. Such a fuel discharge hole 22 can stably discharge liquid fuel toward the anode 13 only by capillary force. Therefore, the fuel supply to the fuel cell can be sufficiently stabilized without impairing the miniaturization of the fuel cell.
　第１の実施形態の具体例（実施例１～８）として、その内周面の液体燃料に対する濡れ角θがいずれも３０°で、表１に示すような各種断面形状を有する燃料排出孔２２を形成した燃料分配機構３を有する燃料電池１を作製した。燃料電池セル（ＭＥＡ）２の大きさは４０×８０ｍｍとし、液体燃料には純メタノールを使用した。また、比較例（比較例１～６）として、燃料排出孔２２を表１に示すような断面形状を有する燃料排出孔に変えた以外は実施例と同一構成の燃料電池を作製した。 As specific examples of the first embodiment (Examples 1 to 8), the wetting angle θ of the inner peripheral surface with respect to the liquid fuel is 30 °, and the fuel discharge holes 22 have various cross-sectional shapes as shown in Table 1. The fuel cell 1 having the fuel distribution mechanism 3 formed with the above was manufactured. The size of the fuel cell (MEA) 2 was 40 × 80 mm, and pure methanol was used as the liquid fuel. As a comparative example (Comparative Examples 1 to 6), a fuel cell having the same configuration as that of the example was manufactured except that the fuel discharge hole 22 was changed to a fuel discharge hole having a cross-sectional shape as shown in Table 1.
　これらの燃料電池の燃料排出孔における液体燃料の吸上げ高さを測定した。測定は、次のような方法で行った。燃料分配機構３と同一の材料を用い、同一の燃料排出孔を１個形成して、試験用燃料分配機構を作製する。この試験用燃料分配機構に純メタノールを加圧せずに供給し、試験用燃料分配機構の側面より液体燃料供給後の吸い上げられた液体燃料の燃料排出孔端面から液面の最大高さまでを測定する。試験用燃料分配機構は、側面から液面を測定できる大きさとする。 The suction height of liquid fuel in the fuel discharge holes of these fuel cells was measured. The measurement was performed by the following method. Using the same material as the fuel distribution mechanism 3, one fuel discharge hole is formed to produce a test fuel distribution mechanism. Supply pure methanol to the test fuel distribution mechanism without applying pressure, and measure from the side of the test fuel distribution mechanism to the maximum height of the liquid level from the end face of the liquid fuel pumped up after liquid fuel supply To do. The test fuel distribution mechanism is sized so that the liquid level can be measured from the side.
　結果を表１に示す。吸上げ高さは、比較例１における吸上げ高さに対する比で示した。実施例１においては、吸上げ高さが上限（吸上げ高さ比として１．１８）に達し、それ以上の測定が不可能であったことから「≧１．１８」と表記した。 The results are shown in Table 1. The wicking height is shown as a ratio to the wicking height in Comparative Example 1. In Example 1, the suction height reached the upper limit (1.18 as the suction height ratio), and no more measurement was possible, so “≧ 1.18” was written.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１から明らかなように、実施例の燃料電池はいずれも、同断面積の比較例の燃料電池に比べ、液体燃料の吸上げ効果に優れていた。 As is clear from Table 1, all the fuel cells of the examples were superior in the liquid fuel suction effect as compared with the fuel cells of the comparative example having the same cross-sectional area.
　次に、燃料排出孔２２の内周面の液体燃料に対する濡れ角θが８０°となる材料を用いた以外は、実施例１および実施例６とそれぞれ同一構成の燃料電池（実施例９および実施例１０）を作製した。これらの実施例９および実施例１０の燃料電池について、上記の場合と同様にして、燃料電池の燃料排出孔における液体燃料の吸上げ高さを測定し、比較例１における吸上げ高さに対する比を求めた。結果を表２に示す。表２には、実施例１および実施例６の燃料電池の測定結果も示した。 Next, a fuel cell having the same configuration as that of Example 1 and Example 6 (Examples 9 and 6) except that a material having a wetting angle θ of 80 ° with respect to the liquid fuel on the inner peripheral surface of the fuel discharge hole 22 was used. Example 10) was prepared. For these fuel cells of Example 9 and Example 10, the suction height of the liquid fuel in the fuel discharge hole of the fuel cell was measured in the same manner as described above, and the ratio to the suction height in Comparative Example 1 was measured. Asked. The results are shown in Table 2. Table 2 also shows the measurement results of the fuel cells of Example 1 and Example 6.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２から明らかなように、濡れ角θが８０°の実施例９および実施例１０に比べ、濡れ角θが３０°の実施例１および実施例６の燃料電池は、液体燃料の吸上げ効果により優れていた。 As is apparent from Table 2, the fuel cells of Examples 1 and 6 having a wetting angle θ of 30 ° are more effective in absorbing liquid fuel than those of Examples 9 and 10 having a wetting angle θ of 80 °. It was better.
　第１の実施形態においては、燃料分配機構３はその内部に設けられた細管２５により燃料を複数の燃料排出孔２２に分配している。このような構造の燃料分配機構３を使用することによって、燃料注入孔２１から燃料分配機構３内に流入した液体燃料を方向や位置にかかわりなく、複数の燃料排出孔２２に均等に分配することができる。 In the first embodiment, the fuel distribution mechanism 3 distributes the fuel to the plurality of fuel discharge holes 22 by the thin tubes 25 provided therein. By using the fuel distribution mechanism 3 having such a structure, the liquid fuel flowing into the fuel distribution mechanism 3 from the fuel injection hole 21 can be evenly distributed to the plurality of fuel discharge holes 22 regardless of the direction and position. Can do.
　また、細管２５で燃料注入孔２１と複数の燃料排出孔２２とを接続することによって、燃料電池１の特定箇所により多くの燃料を供給するような設計が可能となる。例えば、装置装着上の都合から燃料電池１の半分の放熱がよくなってしまうような場合、従来では温度分布が生じてしまい、平均出力の低下が避けられない。これに対して、細管２５の形成パターンを調整し、予め放熱のよい部分に燃料排出孔２２を密に配置することによって、その部分での発電に伴う発熱を多くすることができる。これによって、面内の発電度合いを均一化することができ、出力低下を抑制することが可能となる。 In addition, by connecting the fuel injection hole 21 and the plurality of fuel discharge holes 22 with the thin tube 25, it is possible to design such that more fuel is supplied to a specific portion of the fuel cell 1. For example, in the case where the heat dissipation by half of the fuel cell 1 is improved due to the convenience of mounting the device, a temperature distribution is conventionally generated, and a decrease in average output is inevitable. On the other hand, by adjusting the formation pattern of the thin tubes 25 and arranging the fuel discharge holes 22 densely in advance in a portion where heat dissipation is good, heat generated by power generation in that portion can be increased. Thereby, the in-plane power generation degree can be made uniform, and it is possible to suppress a decrease in output.
　このように燃料注入孔２１と複数の燃料排出孔２２とを細管２５で接続した燃料分配機構３は、燃料電池セルへの燃料の均一化を図る上で優れている。しかし、図５に示すように、燃料分配機構３は、その内部に設けられた空隙部２７から複数の燃料排出孔２２に分配する構造としてもよい。 Thus, the fuel distribution mechanism 3 in which the fuel injection holes 21 and the plurality of fuel discharge holes 22 are connected by the thin tubes 25 is excellent in achieving uniform fuel to the fuel cells. However, as shown in FIG. 5, the fuel distribution mechanism 3 may be configured to distribute to the plurality of fuel discharge holes 22 from the gap portion 27 provided therein.
　図５に示す燃料分配機構３は、液体燃料が流路５を介して流入する少なくとも１個の燃料注入孔２１と、液体燃料やその気化成分を排出する複数の燃料排出孔２２とを有する燃料分配板２３Ａを備えている。燃料分配板２３Ａの内部には、燃料注入孔２１から導かれた液体燃料の通路となる空隙部２７が設けられている。複数の燃料排出孔２２は燃料通路として機能する空隙部２７にそれぞれ接続されている。 The fuel distribution mechanism 3 shown in FIG. 5 has a fuel having at least one fuel injection hole 21 into which liquid fuel flows through the flow path 5 and a plurality of fuel discharge holes 22 through which the liquid fuel and its vaporized components are discharged. A distribution plate 23A is provided. Inside the fuel distribution plate 23 </ b> A, a gap 27 serving as a liquid fuel passage led from the fuel injection hole 21 is provided. The plurality of fuel discharge holes 22 are respectively connected to gaps 27 that function as fuel passages.
　燃料注入孔２１から燃料分配機構３に導入された液体燃料は空隙部２７に入り、この燃料通路として機能する空隙部２７を介して複数の燃料排出孔２２にそれぞれ導かれる。 The liquid fuel introduced into the fuel distribution mechanism 3 from the fuel injection hole 21 enters the gap 27 and is guided to the plurality of fuel discharge holes 22 through the gap 27 that functions as the fuel passage.
　また、燃料分配機構３とアノード１３との間に、例えば図６に示すように多孔体２８を挿入することができる。図６は、図１に示す燃料電池１に多孔体２８を用いた例である。多孔体２８の構成材料としては各種樹脂が使用され、多孔質状態の樹脂フィルム等が多孔体２８として用いられる。このような多孔体２８を配置することによって、アノード１３に対する燃料供給量をより一層平均化することができる。すなわち、燃料分配機構３の燃料排出孔２２から排出された液体燃料は一旦多孔体２８に吸収され、多孔体２８の内部で面内方向に拡散する。この後、多孔体２８からアノード１３に燃料が供給されるため、燃料供給量をより一層平均化することが可能となる。多孔体２８は複数の多孔膜を積層して配置してもよい。 Further, for example, a porous body 28 can be inserted between the fuel distribution mechanism 3 and the anode 13 as shown in FIG. FIG. 6 shows an example in which the porous body 28 is used in the fuel cell 1 shown in FIG. Various resins are used as the constituent material of the porous body 28, and a porous resin film or the like is used as the porous body 28. By disposing such a porous body 28, the amount of fuel supplied to the anode 13 can be further averaged. That is, the liquid fuel discharged from the fuel discharge hole 22 of the fuel distribution mechanism 3 is once absorbed by the porous body 28 and diffuses in the in-plane direction inside the porous body 28. Thereafter, fuel is supplied from the porous body 28 to the anode 13, so that the fuel supply amount can be further averaged. The porous body 28 may be arranged by laminating a plurality of porous films.
　第１の実施形態において、液体燃料を燃料収容部１４から燃料分配機構３まで送る機構は特に限定されるものではない。例えば、使用時の設置場所が固定される場合には、重力を利用して液体燃料を燃料収容部４から燃料分配機構３まで落下させて送液することができる。また、多孔体等を充填した流路５を用いることによって、毛細管現象で燃料収容部４から燃料分配機構３まで送液することができる。さらに、燃料収容部４を加圧しその圧力により液体燃料を燃料収容部４から燃料分配機構３へ送液することができる。 In the first embodiment, the mechanism for sending the liquid fuel from the fuel storage unit 14 to the fuel distribution mechanism 3 is not particularly limited. For example, when the installation location at the time of use is fixed, the liquid fuel can be dropped from the fuel storage unit 4 to the fuel distribution mechanism 3 and fed using gravity. Further, by using the flow path 5 filled with a porous body or the like, the liquid can be fed from the fuel storage portion 4 to the fuel distribution mechanism 3 by a capillary phenomenon. Furthermore, the fuel storage part 4 can be pressurized and the liquid fuel can be sent from the fuel storage part 4 to the fuel distribution mechanism 3 by the pressure.
　また、燃料収容部４から燃料分配機構３への送液は、流路５に介挿させたポンプで実施してもよい。このポンプは、燃料収容部４から燃料分配機構３に液体燃料を送液する目的でのみ使用されるポンプである。このようなポンプで必要時に液体燃料を送液することによって、燃料供給量の制御性を高めることができる。ポンプの種類は特に限定されるものではないが、少量の液体燃料を制御性よく送液することができ、さらに小型軽量化が可能という観点から、ロータリーベーンポンプ、電気浸透流ポンプ、ダイアフラムポンプ、しごきポンプ等を使用することが好ましい。ロータリーベーンポンプはモータで羽を回転させて送液するものである。電気浸透流ポンプは電気浸透流現象を起こすシリカ等の焼結多孔体を用いたものである。ダイアフラムポンプは電磁石や圧電セラミックスによりダイアフラムを駆動して送液するものである。しごきポンプは柔軟性を有する燃料流路の一部を圧迫し、燃料をしごき送るものである。これらのうち、駆動電力や大きさ等の観点から、電気浸透流ポンプや圧電セラミックスを有するダイアフラムポンプを使用することがより好ましい。 Further, the liquid feeding from the fuel storage unit 4 to the fuel distribution mechanism 3 may be performed by a pump inserted in the flow path 5. This pump is used only for the purpose of sending liquid fuel from the fuel storage portion 4 to the fuel distribution mechanism 3. By supplying liquid fuel when necessary with such a pump, the controllability of the fuel supply amount can be improved. The type of pump is not particularly limited, but from the viewpoint that a small amount of liquid fuel can be sent with good controllability, and that further reduction in size and weight is possible, rotary vane pumps, electroosmotic flow pumps, diaphragm pumps, ironing irons. It is preferable to use a pump or the like. A rotary vane pump feeds liquid by rotating a wing with a motor. The electroosmotic flow pump uses a sintered porous material such as silica that causes an electroosmotic flow phenomenon. The diaphragm pump is a pump that feeds liquid by driving the diaphragm with an electromagnet or piezoelectric ceramics. The squeezing pump presses a part of the flexible fuel flow path and squeezes the fuel. Among these, it is more preferable to use an electroosmotic pump or a diaphragm pump having piezoelectric ceramics from the viewpoint of driving power, size, and the like.
　上述した実施形態の燃料電池１は、各種の液体燃料を使用した場合に効果を発揮し、液体燃料の種類や濃度は限定されるものではない。複数の燃料排出孔２２を有する燃料分配機構３の特徴がより顕在化するのは燃料濃度が濃い場合である。このため、上記実施形態の燃料電池１は、濃度が８０％以上のメタノールを液体燃料として用いた場合に、その性能や効果を特に発揮することができる、したがって、上記実施形態は濃度が８０％以上のメタノールを液体燃料として用いた燃料電池に適用することが好ましい。 The fuel cell 1 of the above-described embodiment is effective when various liquid fuels are used, and the type and concentration of the liquid fuel are not limited. The characteristics of the fuel distribution mechanism 3 having a plurality of fuel discharge holes 22 become more apparent when the fuel concentration is high. For this reason, the fuel cell 1 of the above embodiment can particularly exhibit its performance and effects when methanol having a concentration of 80% or more is used as the liquid fuel. Therefore, the above embodiment has a concentration of 80%. It is preferable to apply to the fuel cell using the above methanol as a liquid fuel.
　本発明は液体燃料を使用した各種の燃料電池に適用することができる。また、燃料電池の具体的な構成や燃料の供給状態等も特に限定されるものではない。ＭＥＡに供給される燃料の全てが液体燃料の蒸気、全てが液体燃料、または一部が液体状態で供給される液体燃料の蒸気等、種々形態に本発明を適用することができる。実施段階では本発明の技術的思想を逸脱しない範囲で構成要素を変形して具体化することができる。さらに、上記実施形態に示される複数の構成要素を適宜に組合せたり、また実施形態に示される全構成要素から幾つかの構成要素を削除する等、種々の変形が可能である。本発明の実施形態は本発明の技術的思想の範囲内で拡張もしくは変更することができ、この拡張、変更した実施形態も本発明の技術的範囲に含まれるものである。 The present invention can be applied to various fuel cells using liquid fuel. Further, the specific configuration of the fuel cell, the supply state of the fuel, and the like are not particularly limited. The present invention can be applied to various forms such as liquid fuel vapor supplied to the MEA, liquid fuel vapor, all liquid fuel, or liquid fuel vapor supplied partially in a liquid state. In the implementation stage, the constituent elements can be modified and embodied without departing from the technical idea of the present invention. Furthermore, various modifications are possible, such as appropriately combining a plurality of constituent elements shown in the above embodiments, or deleting some constituent elements from all the constituent elements shown in the embodiments. Embodiments of the present invention can be expanded or modified within the scope of the technical idea of the present invention, and these expanded and modified embodiments are also included in the technical scope of the present invention.
　１…燃料電池、２…燃料電池セル（ＭＥＡ）、３…燃料分配機構、４…燃料収容部、５…流路、１１…アノード触媒層、１２…アノードガス拡散層、１３…アノード（燃料極）、１４…カソード触媒層、１５…カソードガス拡散層、１６…カソード（空気極）、１７…電解質膜、２１…燃料注入孔、２２…燃料排出孔、２３，２３Ａ…燃料分配板、２５…細管、２６…液溜部、２７…空隙部。 DESCRIPTION OF SYMBOLS 1 ... Fuel cell, 2 ... Fuel cell (MEA), 3 ... Fuel distribution mechanism, 4 ... Fuel accommodating part, 5 ... Flow path, 11 ... Anode catalyst layer, 12 ... Anode gas diffusion layer, 13 ... Anode (fuel electrode) ), 14 ... Cathode catalyst layer, 15 ... Cathode gas diffusion layer, 16 ... Cathode (air electrode), 17 ... Electrolyte membrane, 21 ... Fuel injection hole, 22 ... Fuel discharge hole, 23, 23A ... Fuel distribution plate, 25 ... Narrow tube, 26... Liquid reservoir, 27.

Claims (10)

  1. 　燃料極と、空気極と、前記燃料極と前記空気極とに挟持された電解質膜とを有する膜電極接合体と；
    　前記膜電極接合体の前記燃料極側に配置され、前記燃料極の複数個所に対して燃料を分配供給する複数の燃料排出孔を有する燃料分配機構と；
    　液体燃料を収容すると共に、前記燃料分配機構と流路を介して接続された燃料収容部とを具備し、
    　前記燃料分配機構の各燃料排出孔は、周長Ｌが同断面積Ｓの真円の周長Ｌ０より大きい断面形状を有することを特徴とする燃料電池。     A membrane electrode assembly having a fuel electrode, an air electrode, and an electrolyte membrane sandwiched between the fuel electrode and the air electrode;
    A fuel distribution mechanism disposed on the fuel electrode side of the membrane electrode assembly and having a plurality of fuel discharge holes for distributing and supplying fuel to a plurality of locations of the fuel electrode;
    A liquid storage unit, and a fuel storage unit connected to the fuel distribution mechanism via a flow path;
    Each fuel discharge hole, a fuel cell circumferential length L and having a circumferential length L 0 greater than the cross-sectional shape of a true circle ditto area S of the fuel distribution mechanism.
  2. 　請求項１記載の燃料電池において、
    　前記燃料分配機構は、前記液体燃料が前記流路を介して流入する燃料注入孔と、前記燃料注入孔と前記複数の燃料排出孔とを接続する燃料通路とをさらに備えることを特徴とする燃料電池。     The fuel cell according to claim 1, wherein
    The fuel distribution mechanism further includes a fuel injection hole through which the liquid fuel flows through the flow path, and a fuel passage connecting the fuel injection hole and the plurality of fuel discharge holes. battery.
  3. 　請求項２記載の燃料電池において、
    　前記燃料通路は、前記燃料極の面方向に枝状に伸びる細管を有することを特徴とする燃料電池。     The fuel cell according to claim 2, wherein
    The fuel cell according to claim 1, wherein the fuel passage has a narrow tube extending in a branch shape in the surface direction of the fuel electrode.
  4. 　請求項１記載の燃料電池において、
    　前記燃料排出孔の周長Ｌと前記真円の周長Ｌ０との比（Ｌ／Ｌ０）が、１．０～１．４であることを特徴とする燃料電池。     The fuel cell according to claim 1, wherein
    A fuel cell, characterized in that a ratio (L / L 0 ) between the circumference L of the fuel discharge hole and the circumference L 0 of the perfect circle is 1.0 to 1.4.
  5. 　請求項１記載の燃料電池において、
    　前記断面積Ｓは、０．５ｍｍ２以下であることを特徴とする燃料電池。     The fuel cell according to claim 1, wherein
    The fuel cell according to claim 1, wherein the cross-sectional area S is 0.5 mm 2 or less.
  6. 　請求項１記載の燃料電池において、
    　前記液体燃料と前記燃料排出孔内周面との濡れ角が４５°以下であることを特徴とする燃料電池。     The fuel cell according to claim 1, wherein
    A fuel cell, wherein a wetting angle between the liquid fuel and the inner peripheral surface of the fuel discharge hole is 45 ° or less.
  7. 　請求項１記載の燃料電池において、
    　前記燃料分配機構が、樹脂または炭素材料で構成されていることを特徴とする燃料電池。     The fuel cell according to claim 1, wherein
    A fuel cell, wherein the fuel distribution mechanism is made of a resin or a carbon material.
  8. 　請求項１記載の燃料電池において、
    　前記各燃料排出孔の下方に、前記液体燃料を一時的に貯留する断面積が前記各燃料排出孔の断面積より小さい液溜部を設けたことを特徴とする燃料電池。     The fuel cell according to claim 1, wherein
    A fuel cell, wherein a liquid reservoir portion having a cross-sectional area for temporarily storing the liquid fuel smaller than a cross-sectional area of each fuel discharge hole is provided below each fuel discharge hole.
  9. 　請求項１記載の燃料電池において、
    　前記液体燃料は、メタノール燃料であることを特徴とする燃料電池。     The fuel cell according to claim 1, wherein
    The fuel cell, wherein the liquid fuel is methanol fuel.
  10. 　請求項１記載の燃料電池において、
    　前記液体燃料は、メタノール濃度が８０％以上のメタノール水溶液または純メタノールであることを特徴とする燃料電池。     The fuel cell according to claim 1, wherein
    The fuel cell according to claim 1, wherein the liquid fuel is a methanol aqueous solution having a methanol concentration of 80% or more or pure methanol.
PCT/JP2010/000318 2009-01-22 2010-01-21 Fuel battery WO2010084751A1 (en)

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JP2008226583A (en) * 2007-03-12 2008-09-25 Sony Corp Fuel cell, electronic equipment, fuel supply plate, and fuel supply method
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JP2008293856A (en) * 2007-05-25 2008-12-04 Toshiba Corp Fuel cell

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0768791A (en) * 1993-09-03 1995-03-14 Canon Inc Ink jet recorder
JP2007265683A (en) * 2006-03-27 2007-10-11 Gunma Univ Fuel cell
JP2008066275A (en) * 2006-08-11 2008-03-21 Sony Corp Fuel cell, electronic device, and fuel supply method
JP2008243800A (en) * 2007-02-26 2008-10-09 Toshiba Corp Fuel cell
JP2008226583A (en) * 2007-03-12 2008-09-25 Sony Corp Fuel cell, electronic equipment, fuel supply plate, and fuel supply method
JP2008243491A (en) * 2007-03-26 2008-10-09 Toshiba Corp Fuel cell
JP2008293856A (en) * 2007-05-25 2008-12-04 Toshiba Corp Fuel cell

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