WO2005053071A1 - Membrane electrode assembly and fuel cell using same - Google Patents

Membrane electrode assembly and fuel cell using same Download PDF

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Publication number
WO2005053071A1
WO2005053071A1 PCT/JP2004/016969 JP2004016969W WO2005053071A1 WO 2005053071 A1 WO2005053071 A1 WO 2005053071A1 JP 2004016969 W JP2004016969 W JP 2004016969W WO 2005053071 A1 WO2005053071 A1 WO 2005053071A1
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WIPO (PCT)
Prior art keywords
membrane
electrolyte membrane
active region
catalyst layer
catalyst
Prior art date
Application number
PCT/JP2004/016969
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French (fr)
Japanese (ja)
Inventor
Yukihiro Okada
Nobuhiko Hojo
Kohji Yuasa
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Matsushita Electric Industrial Co., Ltd.
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Publication of WO2005053071A1 publication Critical patent/WO2005053071A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
    • H01M8/1018—Polymeric electrolyte materials
    • H01M8/1067—Polymeric electrolyte materials characterised by their physical properties, e.g. porosity, ionic conductivity or thickness
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0065—Solid electrolytes
    • H01M2300/0082—Organic polymers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present invention relates to a membrane electrode assembly and a fuel cell using the same.
  • Fuel cells have attracted attention in fields such as those for automobiles, homes, and portable devices because of their low power generation efficiency and low environmental load.
  • As fuel for automobile or home fuel cells hydrogen obtained by reforming hydrogen, city gas, gasoline, etc. is used.
  • fuel cells using organic fuels such as aqueous methanol solution are attracting attention.
  • These fuel cells include a membrane-electrode assembly (hereinafter, referred to as an electrolyte membrane) including a proton-conductive electrolyte membrane (hereinafter, referred to as an electrolyte membrane) and a pair of catalyst layers disposed on both sides of the electrolyte membrane and having a smaller area than the electrolyte membrane. , MEA).
  • an electrolyte membrane a polymer membrane of high hydrogen ion (proton) conductivity, perfluorosulfonic acid type or hydrocarbon type is known.
  • a sandwich structure is formed between the two diffusion layers on the anode side and the force source side with the MEA interposed therebetween. Further, the sandwich structure is sandwiched between an anode-side separator for supplying a fuel such as an aqueous solution of hydrogen / methanol and a power-side separator for supplying an oxidizing agent such as air.
  • the diffusion layer is an electrode layer having both air permeability and conductivity, for example, a carbon nonwoven fabric.
  • An electrolyte membrane having a cation exchange group expands and contracts according to its water content.
  • the electrolyte membrane expands.
  • the expansion of the electrolyte membrane is larger when an organic fuel such as an aqueous methanol solution is used than when hydrogen is used as a fuel.
  • the electrolyte membrane shrinks when the fuel cell is operated or when exposed to a dry atmosphere. If the expansion and contraction of the electrolyte membrane are repeated according to the water content, the electrolyte membrane may be broken.
  • a fuel cell using an electrolyte membrane having a reduced water content other than at the junction with the catalyst layer is disclosed in, for example, JP-A-2000-223136. It has been disclosed.
  • the electrolyte membrane is provided with a portion having less cation exchange groups.
  • FIG. 6 is a schematic sectional view showing a conventional MEA.
  • the electrolyte membrane 33 is sandwiched between a catalyst layer 34A on the force side and a catalyst layer 34B on the anode side.
  • the activity is relatively lower than that in the other active region 32 because the cation exchange group is small in order to lower the water content.
  • the central portion 43 of the active region 32 is affected not only by the catalyst layer opposed thereto but also by the surrounding catalyst layer. That is, portion 43 is affected by portion 41 of the catalyst layer. The amount of the portion 41 is almost constant when the portion 43 is near the center of the electrolyte membrane 33.
  • the portion 44 of the electrolyte at the periphery of the active region 32 (boundary to the inactive region 31) and facing the periphery of the catalyst layer is different from the portion 43. That is, although there is an opposed catalyst layer, it is affected only from a portion 42 where a part of the catalyst layer surrounding the portion is not present. Therefore, the amount of the catalyst layer in which the portion 44 is affected is smaller than that of the portion 43.
  • the amount and the state of the catalyst layer affected by the portion 43 and the portion 44 are different. Therefore, when a load is applied, the current density distribution in the active region 32 becomes non-uniform, and the characteristics such as the moisturizing performance are affected.
  • a design is made so that a space exists between the electrode layer and the surrounding frame, and an oxidant such as air or a fuel such as hydrogen or methanol is filled in the space.
  • an oxidant such as air or a fuel such as hydrogen or methanol is filled in the space.
  • Portion 43 is affected by the flow through the opposing catalyst layer, while portion 44 is affected by the flow without the partial catalyst layer. This difference causes a variation in the moisturizing performance of the entire electrolyte membrane, and affects the non-uniformity of the current density distribution and the service life.
  • the fuel cell has a problem called a so-called cross leak, in which a fuel such as hydrogen or methanol moves to the force source side through the electrolyte membrane.
  • a fuel such as hydrogen or methanol moves to the force source side through the electrolyte membrane.
  • the amount of cross leak varies between a portion where a catalyst layer is present and a portion where no catalyst layer is present.
  • the amount of cross leak is larger in the part where the catalyst layer is formed on the electrolyte membrane than in the part where only the electrolyte membrane is formed. Minutes are smaller. This is largely due to the relatively dense structure of the catalyst layer, which is slower than the diffusion force of fuel passing therethrough without the catalyst layer.
  • the amount of cross leak is closely related to the amount of cation exchange groups contained in the electrolyte membrane, and the smaller the number of cation exchange groups, the smaller.
  • the amount of the cation exchange group is changed at the boundary between the portion facing the catalyst layer 34A and the portion not facing the catalyst layer 34A.
  • the cross leak at this boundary increases. This is because, as shown by the bold arrow in the figure, when viewed obliquely from the space where the fuel exists at the boundary, the catalyst layer 34B is almost completely contained in the active region 32 with many cation exchange groups in the portion where the catalyst layer 34B is formed. This is because the fuel comes into contact without going through the layer 34B. If the cross leak changes at the boundary, the cross leak amount becomes uneven in the plane of the MEA.
  • the membrane electrode assembly of the present invention has a proton conductive electrolyte membrane and a pair of catalyst layers provided on both surfaces thereof.
  • the proton conductive electrolyte membrane has an active region having a cation exchange group, and an inactive region around the active region, in which the number of cation exchange groups per unit volume is smaller than that of the active region.
  • the inert region is inserted between the pair of catalyst layers. That is, each of the pair of catalyst layers has a larger area than the active region. With this configuration, nonuniformity of the reaction in the catalyst layer is suppressed.
  • the fuel cell of the present invention has the above-mentioned membrane electrode assembly. With this configuration, nonuniformity of the reaction in the catalyst layer is suppressed, and a long-life fuel cell is obtained.
  • FIG. 1A is a schematic cross-sectional view of a membrane electrode assembly (MEA) according to an embodiment of the present invention.
  • FIG. IB is a schematic front view of the MEA shown in FIG. 1A.
  • FIG. 2 is a schematic sectional view of a fuel cell according to an embodiment of the present invention.
  • FIG. 3 is a schematic cross-sectional view of a fuel cell described in an embodiment of the present invention for comparison.
  • FIG. 4 is a diagram showing the relationship between the length of overlap between the inactive region and the catalyst layer and the life when hydrogen is used as the fuel.
  • FIG. 5 is a diagram showing the relationship between the length of overlap between the inactive region and the catalyst layer and the life when methanol is used as a fuel.
  • FIG. 6 is a schematic cross-sectional view of a conventional MEA.
  • FIGS. 1A and IB are a schematic cross-sectional view and a schematic front view of a membrane electrode assembly (MEA) according to an embodiment of the present invention
  • FIG. 2 is a schematic cross-sectional view of a fuel cell having the MEA shown in FIG. 1A. It is.
  • the proton conductive electrolyte membrane (hereinafter, “membrane”) 13 includes an active region 12 having many cation exchange groups and having proton conductivity, and an inactive region having less cation exchange groups than the active region 12. Region 11.
  • the active region 12 is at the center of the film 13 and the inactive region 11 surrounds the active region 12.
  • the inactive region 11 has a smaller number of cation exchange groups per unit volume than the active region 12. It is preferable that the inactive region 11 has no cation exchange group in order to increase the effect.
  • a method for forming the inactive region 11 in the film 13 will be described later.
  • a catalyst layer 14A on the force side is provided on the first surface of the membrane 13, and a catalyst layer 14B on the anode side (fuel electrode side) is provided on the second surface opposite to the first surface. Te ru.
  • the catalyst layers 14A and 14B have a smaller area than the membrane 13.
  • the membrane 13 and the catalyst layers 14A and 14B are in contact with each other so that their centers are almost coincident.
  • the membrane electrode assembly (MEA) 21 has a membrane 13 and catalyst layers 14A and 14B.
  • the catalyst layers 14A and 14B include conductive particles such as carbon carrying a catalyst and a resin binder, and have gas permeability.
  • a diffusion layer 15A on the force side and a diffusion layer 15B on the anode side for dispersing a liquid or gas are in close contact with the catalyst layers 14A and 14B, respectively.
  • an adhesive or a paste may be arranged between the inactive area 11 and the frame 17! /.
  • a separator 18A on the force side and a separator 18B on the anode side are provided so as to sandwich the diffusion layers 15A, 15B and the frame 17.
  • Each of the separators 18A and 18B has a curved S-shaped tortuous channel 24 such as serpentine for supplying an oxidizing agent (air) or fuel.
  • the generated power is output to the catalyst layers 14A and 14B directly or from the diffusion layers 15A and 15B or through the separators 18A and 18B.
  • the catalyst layer 14 A has a contact surface 25 in contact with the inactive region 11 at the periphery.
  • the contact surface 25 surrounds the periphery of the catalyst layer 14A and has a substantially constant width. That is, the catalyst layer 14A covers at least the active layer 12, and has a larger area than the active layer 12.
  • the catalyst layer 14B also has the same contact surface, but the configuration and effects are the same as those of the catalyst layer 14A, and therefore the description is omitted.
  • the catalyst layer 14A Since the catalyst layer 14A has the contact surface 25, the catalyst layer 14A is larger than the active region 12 by the contact surface 25. Therefore, the amount of the catalyst layer affected by the electrolyte present in the active region 12 depends on whether the electrolyte exists in the center of the active region 12 or in the periphery (near the boundary with the inactive region 11). Will be almost the same. As a result, variations in the current density due to differences in the amount of surrounding catalyst, and the effects of flow and cross leaks caused by fuel and oxidant existing between the catalyst layer and the frame are greatly reduced, resulting in uneven reaction. Properties are greatly reduced. Therefore, in the MEA according to the present embodiment, it is possible to suppress a decrease in the life of the electrolyte membrane due to the non-uniformity of the reaction.
  • perfluorosulfonic acid-tetrafluoroethylene having a length of 12 cm, a width of 12 cm, a thickness of 183 ⁇ m, a tensile coefficient of 249 MPa at 50% RH and 23 ° C. and an electric conductivity of 0.083 SZcm, is used.
  • a copolymer film is used.
  • the membrane 13 has a sulfone group as a cation exchange group
  • the film 13 is irradiated with an electron beam to decompose a 3.1 cm-wide sulfone group around the membrane 13. Remove. Thus, the inactive region 11 is formed in the film 13. In addition, the film 13 was formed with a width of 3.1 cm on the periphery. The area other than the inactive area 11, that is, the masked area of 5.8 cm in length and 5.8 cm in width is the active area 12.
  • a method described in JP-A-2000-251905 may be applied. That is, a heavy metal is substituted in a place where a sulfone group is desired to be left, and after irradiation with an electron beam or the like, the heavy metal is replaced with a proton to decompose a sulfone group at a target site.
  • cross-linking may be performed to form a membrane matrix, and then only a necessary portion may be sulfonated by a chemical reaction.
  • a polymer membrane or inorganic thin film having microporosity is physically filled or chemically filled with a proton conductive electrolyte only in a target portion of a base material corresponding to the active region 12. They may be combined.
  • the proton conductivity of both active regions 12 was measured as an index for comparing the number of cation exchange groups per unit volume of the inactive region 11 with the number of cation exchange groups per unit volume. Is shown.
  • the active region 12 and the inactive region 11 are cut out, immersed in water, sandwiched between gold plates, and then measured for proton conductivity by an AC impedance method.
  • the active region 12, a 0. LSZcm, the inactive region 11, is less than 10- 4 S / cm.
  • the amount of cation exchange groups in the active region 12 was 1.77 meqZcm 3 .
  • MeqZcm 3 is an indicator of the ion exchange capacity per volume lcm 3 of the membrane in the dry state, The higher the number, the meaning taste that cation exchange groups is large.
  • the catalyst layer 14A on the force side is formed of catalyst-carrying particles in which 50% by weight of platinum particles having an average particle diameter of about 3nm are supported on conductive carbon particles having an average primary particle diameter of 30nm.
  • the catalyst layer 14B on the anode side is composed of catalyst-supporting particles in which 50% by weight of platinum ruthenium alloy particles having an average particle size of about 3 nm are supported on the same conductive carbon particles.
  • Each of the catalyst-carrying particles, a proton conductor similar to MEA, and water are mixed to prepare a catalyst paste.
  • Each of the pastes thus prepared is applied to one surface of the previously prepared film 13 by a spray method to form catalyst layers 14A and 14B.
  • Ocm are formed in the center of the film 13 using a mask having a hole having a length of 6. Ocm and a width of 6. Ocm.
  • the MEA 21 in which the overlap length of the inactive region 11 and the catalyst layers 14A and 14B is 1. Omm is formed.
  • the amount of the catalyst is about lmg / cm 2 in terms of platinum on both the anode side and the power source side.
  • a frame 17 having a length of 12 cm, a width of 12 cm, and a thickness of 300 / z m having a hole of 6.03 cm ⁇ 6.03 cm is installed on both sides of the MEA 21.
  • Diffusion layers 15A and 15B made of carbon paper having a size of OOcm x 6000cm and a thickness of 360m are placed in the holes.
  • a fuel cell (Sample A) as shown in Fig. 2 was obtained by sandwiching it between separators 18A and 18B, which are 4 mm thick and have a thickness of lmm and a width of lmm, in which grooves for liquid and gas flow are formed. Is received.
  • Separators 18A and 18B and a metal plate are provided with a fuel inlet 26 and a discharge outlet 27 on the anode side, and a suction port 28 and a discharge port 29 for an oxidant such as air on the power source side, respectively. Fuel and air and the like are supplied to the fuel cell using the respective pumps.
  • the size of the lead plate used in the preparation of Sample B is 5.94cm x 5.94cm. In this case, the overlap length of the inactive region 11 and the catalyst layers 14A and 14B is 0.3 mm.
  • the size of the lead plate used when preparing sample C is 5.90 cm X 5.90 cm. In this case, the overlap length of the inactive region 11 and the catalyst layers 14A and 14B is 0.5 mm.
  • the size of the lead plate used in the preparation of Sample D is 5. OOcm x 5. OOcm. In this case, the overlap length of the inert region 11 and the catalyst layers 14A and 14B is 5 mm.
  • Sample E The size of the lead plate used in the preparation of the sample is 4. OOcm X 4. OOcm. In this case, the overlap length of the inert region 11 and the catalyst layers 14A and 14B is 10 mm.
  • FIG. 3 shows a cross-sectional view of the fuel cell of Sample F.
  • a 2 mol ZL aqueous methanol solution is supplied as a fuel from the anode side at 2 mL Zmin, and air as an oxidant is supplied at 1 L Zmin from the power source side.
  • the temperature of the fuel cell is 60 ° C.
  • FIG. 5 shows the result of plotting this index with respect to the length of overlap between the inactive region 11 from which the sulfone group has been removed and the catalyst layers 14A and 14B.
  • Samples A to E the vicinity of the boundary between fuel and air existing between MEA 21 and surrounding frame 17 and the inactive region 11 of active region 12 is the same as Sample F shown in FIG. Compared to the structure of the above, they are isolated by the catalyst layers 14A and 14B. Therefore, the vicinity of the boundary between the active region 12 and the inactive region 11 is not affected by the flow of fuel or air. Therefore, variation in the moisturizing performance of the entire membrane 13 is suppressed, unevenness of the current density distribution is suppressed, and the life of the fuel cell is improved.
  • the difference in the influence of the fuel and air flows also affects the difference in the amount of cross leak. Since the amount of cross-leakage of hydrogen is relatively small, there is no difference in the initial voltage between sample F and samples A-E in power generation using hydrogen as fuel. When methanol is used as the fuel, which is susceptible to cross-leakage, the initial voltage of samples A to E is higher than that of sample F, and cross-leakage is suppressed.
  • the life of sample C in which the overlap region between the inactive region 11 and the catalyst layers 14A, 14B is 0.5 mm, is significantly improved as compared with the sample F and the sample B. are doing. That is, the length of the overlap between the inactive region 11 and the catalyst layers 14A and 14B (the length of the contact surface 25) is preferably 0.5 mm or more. 1 mm or more is more desirable.
  • the length of the contact surface 25 is desirably 5 mm or less.
  • the catalyst layers 14 A and 14 B have a smaller area than the membrane 13, but also for the same reason as described above, and for the reason that the fuel cell is sealed with the frame 17.
  • the frame 17 may not be used but may be configured by impregnating the diffusion layer with an adhesive, for example.
  • the length of the overlap between the catalyst layer 14A and the inactive region 11 and the length of the overlap between the catalyst layer 14B and the inactive region 11 may be different! / !. Further, the inactive region 11 may not be formed over the entire thickness direction of the film 13.
  • a hydrocarbon-based film or a material in which a porous substrate is filled with a proton-conductive substance can also provide the same effect.
  • the catalyst layers 14A and 14B may be made of the same proton conductor as the MEA but different in proton conductor.
  • methanol is used as the organic fuel.
  • other organic fuels having a high degree of swelling of the membrane 13 show the same tendency.
  • the present invention is effective when an organic fuel such as an alcohol, an ether, or a methoxy-containing compound is used.
  • the MEA according to the present invention is useful for a fuel cell having excellent life characteristics.

Abstract

Disclosed is a membrane electrode assembly comprising a proton conductive electrolyte membrane and a pair of catalyst layers respectively arranged on either side of the membrane. The proton conductive electrolyte membrane comprises an active region having cation exchange groups and an inactive region around the active region. The number of cation exchange groups per unit volume in the inactive region is smaller than that in the active region. The inactive region is interposed between the pair of catalyst layers.

Description

明 細 書  Specification
膜電極接合体とそれを用いた燃料電池  Membrane electrode assembly and fuel cell using the same
技術分野  Technical field
[0001] 本発明は、膜電極接合体とそれを用いた燃料電池に関する。  The present invention relates to a membrane electrode assembly and a fuel cell using the same.
背景技術  Background art
[0002] 燃料電池は、発電効率が高ぐ環境への負荷も小さいことから、自動車用、家庭用 、携帯機器用などの分野で注目されてきている。自動車用あるいは家庭用の燃料電 池の燃料としては、水素、都市ガス、ガソリン等を改質して得られる水素が使用されて いる。また、携帯機器用としては、メタノール水溶液などの有機物燃料を使用した燃 料電池が注目されている。  [0002] Fuel cells have attracted attention in fields such as those for automobiles, homes, and portable devices because of their low power generation efficiency and low environmental load. As fuel for automobile or home fuel cells, hydrogen obtained by reforming hydrogen, city gas, gasoline, etc. is used. For mobile devices, fuel cells using organic fuels such as aqueous methanol solution are attracting attention.
[0003] これらの燃料電池には、プロトン伝導性電解質膜 (以下、電解質膜)と、電解質膜の 両面に配置され、電解質膜より面積の小さい一対の触媒層とからなる膜電極接合体 (以下、 MEA)が用いられている。電解質膜としては、水素イオン (プロトン)伝導性の 高 、パーフルォロスルホン酸系または炭化水素系の高分子膜が知られて 、る。  [0003] These fuel cells include a membrane-electrode assembly (hereinafter, referred to as an electrolyte membrane) including a proton-conductive electrolyte membrane (hereinafter, referred to as an electrolyte membrane) and a pair of catalyst layers disposed on both sides of the electrolyte membrane and having a smaller area than the electrolyte membrane. , MEA). As the electrolyte membrane, a polymer membrane of high hydrogen ion (proton) conductivity, perfluorosulfonic acid type or hydrocarbon type is known.
[0004] MEAを用いた燃料電池では、アノード側と力ソード側の 2枚の拡散層が MEAを挟 み込んでサンドイッチ構造が形成されて 、る。さらにこのサンドイッチ構造を水素ゃメ タノール水溶液などの燃料を供給するアノード側のセパレータと、空気などの酸化剤 を供給する力ソード側のセパレータとが挟み込んでいる。拡散層は、通気性と導電性 とを兼ね備えた、例えばカーボン不織布力もなる電極層である。  [0004] In a fuel cell using MEA, a sandwich structure is formed between the two diffusion layers on the anode side and the force source side with the MEA interposed therebetween. Further, the sandwich structure is sandwiched between an anode-side separator for supplying a fuel such as an aqueous solution of hydrogen / methanol and a power-side separator for supplying an oxidizing agent such as air. The diffusion layer is an electrode layer having both air permeability and conductivity, for example, a carbon nonwoven fabric.
[0005] 陽イオン交換基を有する電解質膜は、その水分含有量に応じて膨張'収縮する。  [0005] An electrolyte membrane having a cation exchange group expands and contracts according to its water content.
燃料電池を運転しているとき、力ソード側の触媒層では水が生成するため、電解質膜 は膨張する。また電解質膜の膨張は、メタノール水溶液などの有機燃料を用いるとき の方が、水素を燃料として使用するときより大きい。また、電解質膜は、燃料電池を運 転して!/ヽな!ヽ場合や乾燥雰囲気にさらされると収縮する。このように水分含有量に応 じて電解質膜の膨張 '収縮が繰り返されると、電解質膜が破れる可能性がある。  During operation of the fuel cell, water is generated in the catalyst layer on the power source side, so that the electrolyte membrane expands. The expansion of the electrolyte membrane is larger when an organic fuel such as an aqueous methanol solution is used than when hydrogen is used as a fuel. In addition, the electrolyte membrane shrinks when the fuel cell is operated or when exposed to a dry atmosphere. If the expansion and contraction of the electrolyte membrane are repeated according to the water content, the electrolyte membrane may be broken.
[0006] このような電解質膜の破れを抑制するために、触媒層との接合部以外の含水率を 低下させた電解質膜を使用した燃料電池が例えば、特開 2000-223136号公報に 開示されている。この燃料電池では、電解質膜には陽イオン交換基の少ない部分が 設けられている。 [0006] In order to suppress such breakage of the electrolyte membrane, a fuel cell using an electrolyte membrane having a reduced water content other than at the junction with the catalyst layer is disclosed in, for example, JP-A-2000-223136. It has been disclosed. In this fuel cell, the electrolyte membrane is provided with a portion having less cation exchange groups.
[0007] しかし、この構成では、触媒層と接合している電解質膜において、周縁部と中央部 との間で、反応が不均一になる。この理由を、図 6を参照しながら説明する。  [0007] However, in this configuration, the reaction becomes uneven between the peripheral portion and the central portion in the electrolyte membrane bonded to the catalyst layer. The reason will be described with reference to FIG.
[0008] 図 6は従来の MEAを表す概略断面図である。電解質膜 33は、力ソード側の触媒 層 34Aとアノード側の触媒層 34Bとに狭持されている。触媒層 34A、 34Bと接合する 部分以外の不活性領域 31では、それ以外の活性領域 32よりも含水率を低下させる ために陽イオン交換基が少なぐ活性度が相対的に低い。  FIG. 6 is a schematic sectional view showing a conventional MEA. The electrolyte membrane 33 is sandwiched between a catalyst layer 34A on the force side and a catalyst layer 34B on the anode side. In the inactive region 31 other than the portion bonded to the catalyst layers 34A and 34B, the activity is relatively lower than that in the other active region 32 because the cation exchange group is small in order to lower the water content.
[0009] 活性領域 32の中央部にある部分 43は、それに対向する触媒層だけではなぐ周 囲の触媒層からも影響される。すなわち、部分 43は、触媒層の部分 41から影響され る。部分 41の量は、部分 43が電解質膜 33の中央部付近にある場合においては、ほ ぼ一定である。  [0009] The central portion 43 of the active region 32 is affected not only by the catalyst layer opposed thereto but also by the surrounding catalyst layer. That is, portion 43 is affected by portion 41 of the catalyst layer. The amount of the portion 41 is almost constant when the portion 43 is near the center of the electrolyte membrane 33.
[0010] しかし、活性領域 32の周縁部（不活性領域 31との境界部）にあり、かつ触媒層の周 縁部と対向している電解質の部分 44は、部分 43とは異なる。すなわち、対向する触 媒層は存在するが、その部分を取り囲む触媒層の一部が無ぐ部分 42からのみ影響 される。したがって、部分 44が影響を受ける触媒層の量は、部分 43よりも小さくなる。  [0010] However, the portion 44 of the electrolyte at the periphery of the active region 32 (boundary to the inactive region 31) and facing the periphery of the catalyst layer is different from the portion 43. That is, although there is an opposed catalyst layer, it is affected only from a portion 42 where a part of the catalyst layer surrounding the portion is not present. Therefore, the amount of the catalyst layer in which the portion 44 is affected is smaller than that of the portion 43.
[0011] このように、部分 43と部分 44とで影響を受ける触媒層の量や状態が異なる。そのた め、負荷がかかった場合、活性領域 32の電流密度分布の不均一化や保湿性能など の特性に影響し、寿命などに影響を及ぼす。  [0011] As described above, the amount and the state of the catalyst layer affected by the portion 43 and the portion 44 are different. Therefore, when a load is applied, the current density distribution in the active region 32 becomes non-uniform, and the characteristics such as the moisturizing performance are affected.
[0012] またこの種の燃料電池では、電極層とその周囲の枠体との間には空間が存在する ように設計されており、ここを空気などの酸化剤や水素やメタノール等の燃料が流れ る。部分 43は対向する触媒層を介した流れの影響を受けるのに対し、部分 44は、一 部触媒層を介しない流れの影響を受ける。この違いは、電解質膜全体の保湿性能の ノ ラツキなどを引き起こし、電流密度分布の不均一化、寿命などに影響を与える。  [0012] Further, in this type of fuel cell, a design is made so that a space exists between the electrode layer and the surrounding frame, and an oxidant such as air or a fuel such as hydrogen or methanol is filled in the space. Flows. Portion 43 is affected by the flow through the opposing catalyst layer, while portion 44 is affected by the flow without the partial catalyst layer. This difference causes a variation in the moisturizing performance of the entire electrolyte membrane, and affects the non-uniformity of the current density distribution and the service life.
[0013] さらに燃料電池は、水素やメタノールなどの燃料が電解質膜を通過して力ソード側 へ移動する、いわゆるクロスリークと呼ばれる課題を有する。クロスリークの量は、触媒 層の存在する部分と触媒層の存在しない部分とで変化することが知られている。クロ スリーク量は、電解質膜のみの部位よりも、電解質膜の上に触媒層が構成された部 分の方が小さい。これは、触媒層が比較的緻密な構造のためここを通る燃料の拡散 力 触媒層の無い部分を通る燃料の拡散に比べて遅いことが大きな要因である。ま たクロスリークの量は、電解質膜に含まれる陽イオン交換基の量とも密接に関連があ り、陽イオン交換基が少ない方が小さい。 [0013] Further, the fuel cell has a problem called a so-called cross leak, in which a fuel such as hydrogen or methanol moves to the force source side through the electrolyte membrane. It is known that the amount of cross leak varies between a portion where a catalyst layer is present and a portion where no catalyst layer is present. The amount of cross leak is larger in the part where the catalyst layer is formed on the electrolyte membrane than in the part where only the electrolyte membrane is formed. Minutes are smaller. This is largely due to the relatively dense structure of the catalyst layer, which is slower than the diffusion force of fuel passing therethrough without the catalyst layer. Further, the amount of cross leak is closely related to the amount of cation exchange groups contained in the electrolyte membrane, and the smaller the number of cation exchange groups, the smaller.
[0014] し力 図 6に示す電解質膜 33のように、触媒層 34Aに対向する部分と対向しない 部分との境界で陽イオン交換基の量を変化させて 、る場合、触媒層に対向しな！ヽ不 活性領域 31の近傍に存在する燃料によって、この境界部分でのクロスリークが多くな る。これは図中太矢印で示すように、境目部分で燃料の存在する空間から斜め横方 向からみると、触媒層 34Bが構成された部分の陽イオン交換基の多い活性領域 32 に、ほとんど触媒層 34Bを介せずに燃料が接するためである。クロスリークが境目部 分で変化すると、 MEAの面内でクロスリーク量が不均一になる。クロスリークにより燃 料が力ソード側の触媒層 34Aへ流出すると、燃料のロス、電圧の低下、発熱などによ る寿命の低下、これらの問題の電解質膜 33内での不均一な発生等、多くの問題が 生じる。そのためクロスリーク量を低減することが必要である。このようなクロスリークは 、燃料として、アルコール類、エーテル類、及びメトキシ類含有ィ匕合物もしくはこれら の水溶液を用いたときに大きい。  As shown in FIG. 6, the amount of the cation exchange group is changed at the boundary between the portion facing the catalyst layer 34A and the portion not facing the catalyst layer 34A. What! (4) Due to the fuel present in the vicinity of the inert region 31, the cross leak at this boundary increases. This is because, as shown by the bold arrow in the figure, when viewed obliquely from the space where the fuel exists at the boundary, the catalyst layer 34B is almost completely contained in the active region 32 with many cation exchange groups in the portion where the catalyst layer 34B is formed. This is because the fuel comes into contact without going through the layer 34B. If the cross leak changes at the boundary, the cross leak amount becomes uneven in the plane of the MEA. If fuel leaks to the catalyst layer 34A on the power source side due to cross leak, loss of fuel, reduction of voltage, shortening of service life due to heat generation, and the like, non-uniform generation of these problems in the electrolyte membrane 33, etc. Many problems arise. Therefore, it is necessary to reduce the amount of cross leak. Such a cross leak is large when an alcohol, an ether, and a methoxy-containing compound or an aqueous solution thereof is used as a fuel.
発明の開示  Disclosure of the invention
[0015] 本発明の膜電極接合体は、プロトン伝導性電解質膜とその両面に設けられた一対 の触媒層を有する。プロトン伝導性電解質膜は、陽イオン交換基を有する活性領域 と、活性領域の周囲に、活性領域よりも陽イオン交換基の単位体積あたりの数が少な い不活性領域とを有する。不活性領域は、一対の触媒層の間に挿入されている。す なわち、一対の触媒層はそれぞれ活性領域よりも面積が大きい。この構成により、触 媒層における反応の不均一化が抑制される。また本発明の燃料電池は上記膜電極 接合体を有する。この構成により、触媒層における反応の不均一化が抑制されて長 寿命の燃料電池が得られる。  [0015] The membrane electrode assembly of the present invention has a proton conductive electrolyte membrane and a pair of catalyst layers provided on both surfaces thereof. The proton conductive electrolyte membrane has an active region having a cation exchange group, and an inactive region around the active region, in which the number of cation exchange groups per unit volume is smaller than that of the active region. The inert region is inserted between the pair of catalyst layers. That is, each of the pair of catalyst layers has a larger area than the active region. With this configuration, nonuniformity of the reaction in the catalyst layer is suppressed. The fuel cell of the present invention has the above-mentioned membrane electrode assembly. With this configuration, nonuniformity of the reaction in the catalyst layer is suppressed, and a long-life fuel cell is obtained.
図面の簡単な説明  Brief Description of Drawings
[0016] [図 1A]図 1Aは本発明の実施の形態による膜電極接合体 (MEA)の概略断面図であ る。 [図 IB]図 IBは図 1Aに示す MEAの概略正面図である。 FIG. 1A is a schematic cross-sectional view of a membrane electrode assembly (MEA) according to an embodiment of the present invention. [FIG. IB] FIG. IB is a schematic front view of the MEA shown in FIG. 1A.
圆 2]図 2は本発明の実施の形態による燃料電池の概略断面図である。 [2] FIG. 2 is a schematic sectional view of a fuel cell according to an embodiment of the present invention.
[図 3]図 3は本発明の実施の形態において比較のために説明する燃料電池の概略断 面図である。  FIG. 3 is a schematic cross-sectional view of a fuel cell described in an embodiment of the present invention for comparison.
圆 4]図 4は燃料として水素を用いた場合の、不活性領域と触媒層との重なりの長さと 寿命との関係を示す図である。 [4] FIG. 4 is a diagram showing the relationship between the length of overlap between the inactive region and the catalyst layer and the life when hydrogen is used as the fuel.
[図 5]図 5は燃料としてメタノールを用 ヽた場合の、不活性領域と触媒層との重なりの 長さと寿命との関係を示す図である。  FIG. 5 is a diagram showing the relationship between the length of overlap between the inactive region and the catalyst layer and the life when methanol is used as a fuel.
[図 6]図 6は従来の MEAの概略断面図である。  FIG. 6 is a schematic cross-sectional view of a conventional MEA.
符号の説明 Explanation of symbols
11 不活性領域 11 Inactive area
12 活性領域  12 Active area
13 プロトン伝導性電解質膜  13 Proton conductive electrolyte membrane
14A カソー -ド側の触媒層  14A Cathode-side catalyst layer
14B ァノー -ド側の触媒層  14B Catalyst layer on anode side
15A カソー -ド側の拡散層  15A Cathode-side diffusion layer
15B ァノー -ド側の拡散層  15B Anode-side diffusion layer
17 枠体  17 Frame
18A カソー -ド側のセパレ -タ  18A Cassode-Separation on the side
18B ァノー -ド側のセパレー -タ  18B Anode-Separator on the side
21 膜電極接合体  21 Membrane electrode assembly
24 流路  24 channels
25 接触面  25 contact surface
26 燃料の吸入口  26 Fuel inlet
27 燃料の排出口  27 Fuel outlet
28 酸化剤の吸入口  28 Oxidant inlet
29 酸化剤の排出口  29 Oxidant outlet
31 不活性領域 32 活性領域 31 Inactive area 32 active area
33 電解質膜  33 Electrolyte membrane
34A 力ソード側の触媒層  34A catalyst layer on the side of force
34B アノード側の触媒層  34B Anode side catalyst layer
41, 42, 43, 44 部分  41, 42, 43, 44 pieces
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0018] 図 1A、図 IBは本発明の実施の形態における膜電極接合体 (MEA)の概略断面 図と概略正面図であり、図 2は図 1Aに示す MEAを有する燃料電池の概略断面図で ある。 FIGS. 1A and IB are a schematic cross-sectional view and a schematic front view of a membrane electrode assembly (MEA) according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of a fuel cell having the MEA shown in FIG. 1A. It is.
[0019] プロトン伝導性電解質膜 (以下、膜） 13は、多くの陽イオン交換基を有しプロトン伝 導性を有する活性領域 12と、活性領域 12よりも陽イオン交換基が少ない不活性領 域 11とを有する。活性領域 12は膜 13の中央部にあり、不活性領域 11は活性領域 1 2の周囲を取り囲んでいる。不活性領域 11は活性領域 12よりも単位体積当たりの陽 イオン交換基の数が少ない。なお、不活性領域 11は、効果を大きくするために、陽ィ オン交換基が存在しないことが好ましい。また、膜 13に不活性領域 11を作製する方 法については後述する。  The proton conductive electrolyte membrane (hereinafter, “membrane”) 13 includes an active region 12 having many cation exchange groups and having proton conductivity, and an inactive region having less cation exchange groups than the active region 12. Region 11. The active region 12 is at the center of the film 13 and the inactive region 11 surrounds the active region 12. The inactive region 11 has a smaller number of cation exchange groups per unit volume than the active region 12. It is preferable that the inactive region 11 has no cation exchange group in order to increase the effect. A method for forming the inactive region 11 in the film 13 will be described later.
[0020] 膜 13の第 1面には力ソード側 (空気極側）の触媒層 14Aが、第 1面と対向する第 2 面にはアノード側 (燃料極側）の触媒層 14Bが設けられて 、る。触媒層 14A、 14Bは 膜 13よりも面積が小さい。膜 13と触媒層 14A、 14Bとは、それぞれの中心がほぼ一 致するように接している。膜電極接合体 (MEA) 21は膜 13と触媒層 14A、 14Bとを 有する。  [0020] A catalyst layer 14A on the force side (air electrode side) is provided on the first surface of the membrane 13, and a catalyst layer 14B on the anode side (fuel electrode side) is provided on the second surface opposite to the first surface. Te ru. The catalyst layers 14A and 14B have a smaller area than the membrane 13. The membrane 13 and the catalyst layers 14A and 14B are in contact with each other so that their centers are almost coincident. The membrane electrode assembly (MEA) 21 has a membrane 13 and catalyst layers 14A and 14B.
[0021] 触媒層 14A、 14Bは、触媒が担持されたカーボン等の導電性粒子と榭脂バインダ とを有し、かつ通気性を有する。触媒層 14A、 14Bには、それぞれ、液体やガスを拡 散させるための力ソード側の拡散層 15Aとアノード側の拡散層 15Bとが密着して 、る  [0021] The catalyst layers 14A and 14B include conductive particles such as carbon carrying a catalyst and a resin binder, and have gas permeability. A diffusion layer 15A on the force side and a diffusion layer 15B on the anode side for dispersing a liquid or gas are in close contact with the catalyst layers 14A and 14B, respectively.
[0022] 不活性領域 11には、ガスケットと呼ばれる燃料やガスを通さな ヽ枠体 17が密着し ている。不活性領域 11と枠体 17との間の密着性を向上させるために、不活性領域 1 1と枠体 17との間に接着剤やペーストを配置してもよ!/、。 [0023] また、拡散層 15A、 15Bと枠体 17とを挟むように、力ソード側のセパレータ 18Aとァ ノード側のセパレータ 18Bとが設けられている。セパレータ 18A、 18Bはそれぞれ酸 ィ匕剤 (空気)または燃料を供給するために、例えばサーペンタインと呼ばれるような曲 力 Sりくねつた流路 24が形成されている。 [0022] A frame 17 called a gasket, which is permeable to fuel or gas, is in close contact with the inert region 11. In order to improve the adhesion between the inactive area 11 and the frame 17, an adhesive or a paste may be arranged between the inactive area 11 and the frame 17! /. Further, a separator 18A on the force side and a separator 18B on the anode side are provided so as to sandwich the diffusion layers 15A, 15B and the frame 17. Each of the separators 18A and 18B has a curved S-shaped tortuous channel 24 such as serpentine for supplying an oxidizing agent (air) or fuel.
[0024] 発電された電力は、触媒層 14A、 14B力も直接、もしくは拡散層 15A、 15Bから、 あるいはセパレータ 18A、 18Bを通じて外部に出力される。  [0024] The generated power is output to the catalyst layers 14A and 14B directly or from the diffusion layers 15A and 15B or through the separators 18A and 18B.
[0025] ここで、触媒層 14Aは周縁部に、不活性領域 11と接する接触面 25を有している。  Here, the catalyst layer 14 A has a contact surface 25 in contact with the inactive region 11 at the periphery.
接触面 25は、触媒層 14Aの周縁を取り囲んでおり、ほぼ一定の幅を有している。す なわち、触媒層 14Aは少なくとも活性層 12を覆い、活性層 12よりも面積が大きい。触 媒層 14Bも同様の接触面を有するが、その構成、効果については触媒層 14Aと同 一のため、説明を省略する。  The contact surface 25 surrounds the periphery of the catalyst layer 14A and has a substantially constant width. That is, the catalyst layer 14A covers at least the active layer 12, and has a larger area than the active layer 12. The catalyst layer 14B also has the same contact surface, but the configuration and effects are the same as those of the catalyst layer 14A, and therefore the description is omitted.
[0026] 触媒層 14Aが接触面 25を有するため、触媒層 14Aは活性領域 12よりも接触面 25 だけ大きい。そのため、活性領域 12に存在する電解質が影響を受ける触媒層の量 は、電解質が活性領域 12の中央部に存在しても、周縁部 (不活性領域 11との境界 付近）に存在しても、ほぼ同じになる。このため、周囲の触媒量の違いによる電流密 度のバラツキや、触媒層と枠体との間に存在する燃料や酸化剤による流れやクロスリ ークの影響が大幅に低減され、反応の不均一性が大幅に抑制される。したがって、 本実施の形態による MEAでは、反応の不均一性に起因する電解質膜の寿命の低 下を抑制することが可能である。  Since the catalyst layer 14A has the contact surface 25, the catalyst layer 14A is larger than the active region 12 by the contact surface 25. Therefore, the amount of the catalyst layer affected by the electrolyte present in the active region 12 depends on whether the electrolyte exists in the center of the active region 12 or in the periphery (near the boundary with the inactive region 11). Will be almost the same. As a result, variations in the current density due to differences in the amount of surrounding catalyst, and the effects of flow and cross leaks caused by fuel and oxidant existing between the catalyst layer and the frame are greatly reduced, resulting in uneven reaction. Properties are greatly reduced. Therefore, in the MEA according to the present embodiment, it is possible to suppress a decrease in the life of the electrolyte membrane due to the non-uniformity of the reaction.
[0027] 以下、本発明の実施の形態について、具体例を用いて説明する。まず、 MAE21と それを用いた燃料電池の製造方法にっ 、て説明する。  Hereinafter, embodiments of the present invention will be described using specific examples. First, the MAE21 and a method of manufacturing a fuel cell using the MAE21 will be described.
[0028] 膜 13として、長さ 12cm、幅 12cm、厚さ 183 μ m、 50%RH、 23°Cにおける引張係 数 249MPa、電気伝導度 0. 083SZcmの、パーフルォロスルホン酸ーテトラフルォ 口エチレン共重合体膜を用いる。膜 13は、陽イオン交換基としてスルホン基を有する  As the membrane 13, perfluorosulfonic acid-tetrafluoroethylene having a length of 12 cm, a width of 12 cm, a thickness of 183 μm, a tensile coefficient of 249 MPa at 50% RH and 23 ° C. and an electric conductivity of 0.083 SZcm, is used. A copolymer film is used. The membrane 13 has a sulfone group as a cation exchange group
[0029] 膜 13を長さ 5. 8cm、幅 5. 8cmの鉛板によって中心部をマスキングした後、電子線 を照射して、膜 13の周囲の、 3. 1cmの幅のスルホン基を分解除去する。このようにし て膜 13に不活性領域 11を形成する。なお、膜 13の周縁部に幅 3. 1cmで形成した 不活性領域 11以外の部分、即ちマスキングされた長さ 5. 8cm、幅 5. 8cmの領域が 活性領域 12である。 [0029] After masking the center of the membrane 13 with a lead plate 5.8 cm in length and 5.8 cm in width, the film 13 is irradiated with an electron beam to decompose a 3.1 cm-wide sulfone group around the membrane 13. Remove. Thus, the inactive region 11 is formed in the film 13. In addition, the film 13 was formed with a width of 3.1 cm on the periphery. The area other than the inactive area 11, that is, the masked area of 5.8 cm in length and 5.8 cm in width is the active area 12.
[0030] なお、上記方法の代わりに、特開 2000— 251905に記載されている方法を適用し てもよい。すなわち、スルホン基を残しておきたいところに重金属を置換し、電子線等 の放射線を照射したのち、重金属をプロトンで置換することで、目的とする部位のス ルホン基を分解させる。さらに別の方法として、架橋可能なモノマーを用いて重合し た後、架橋して膜マトリクスを作製し、その後化学反応により必要な部位のみスルホン 化してもよい。また、別の方法としては、微多孔を有する高分子膜や無機薄膜に、活 性領域 12に相当する、基材の目的とする部分にのみプロトン伝導性電解質を物理 的に充填もしくは化学的に結合させてもよい。本実施の形態では、活性領域 12の陽 イオン交換基の数と、不活性領域 11の、単位体積あたりの陽イオン交換基の数とを 比較する指標として、両者のプロトン伝導率を測定した結果を示す。  [0030] Instead of the above method, a method described in JP-A-2000-251905 may be applied. That is, a heavy metal is substituted in a place where a sulfone group is desired to be left, and after irradiation with an electron beam or the like, the heavy metal is replaced with a proton to decompose a sulfone group at a target site. As yet another method, after polymerizing using a crosslinkable monomer, cross-linking may be performed to form a membrane matrix, and then only a necessary portion may be sulfonated by a chemical reaction. As another method, a polymer membrane or inorganic thin film having microporosity is physically filled or chemically filled with a proton conductive electrolyte only in a target portion of a base material corresponding to the active region 12. They may be combined. In this embodiment, the proton conductivity of both active regions 12 was measured as an index for comparing the number of cation exchange groups per unit volume of the inactive region 11 with the number of cation exchange groups per unit volume. Is shown.
[0031] 単位体積あたりの陽イオン交換基の数とプロトン伝導度との間には密接な関係があ り、陽イオン交換基の数が多いほど膜 13のプロトン伝導度は大きくなる。そこで、活性 領域 12、不活性領域 11を切り出し、それぞれ水中に浸祈し、金の板で挟み込んだ 後、交流インピーダンス法でプロトン伝導度を測定する。その結果、活性領域 12では 、 0. lSZcmであり、不活性領域 11では、 10— 4S/cm以下である。分析したところ、 活性領域 12での陽イオン交換基量は、 1. 77meqZcm3である。一方、不活性領域 11ではプロトン伝導率が非常に小さいことから、陽イオン交換基量はゼロに近い値で あると推察される。ここで meqZcm3とは、乾燥状態の膜の体積 lcm3あたりのイオン 交換容量を示す指標であり、この数値が大きいほど、陽イオン交換基が多いことを意 味する。 [0031] There is a close relationship between the number of cation exchange groups per unit volume and the proton conductivity, and the proton conductivity of the membrane 13 increases as the number of cation exchange groups increases. Therefore, the active region 12 and the inactive region 11 are cut out, immersed in water, sandwiched between gold plates, and then measured for proton conductivity by an AC impedance method. As a result, the active region 12, a 0. LSZcm, the inactive region 11, is less than 10- 4 S / cm. As a result of analysis, the amount of cation exchange groups in the active region 12 was 1.77 meqZcm 3 . On the other hand, since the proton conductivity is very small in the inert region 11, the amount of cation exchange groups is estimated to be close to zero. Here, MeqZcm 3 is an indicator of the ion exchange capacity per volume lcm 3 of the membrane in the dry state, The higher the number, the meaning taste that cation exchange groups is large.
[0032] 力ソード側の触媒層 14Aは、平均一次粒子径 30nmの導電性カーボン粒子に平均 粒径約 3nmの白金粒子を 50重量％担持した触媒担持粒子から構成する。また、ァ ノード側の触媒層 14Bは、同様の導電性カーボン粒子に平均粒径約 3nmの白金ル テ -ゥム合金粒子を 50重量％担持した触媒担持粒子から構成する。  [0032] The catalyst layer 14A on the force side is formed of catalyst-carrying particles in which 50% by weight of platinum particles having an average particle diameter of about 3nm are supported on conductive carbon particles having an average primary particle diameter of 30nm. The catalyst layer 14B on the anode side is composed of catalyst-supporting particles in which 50% by weight of platinum ruthenium alloy particles having an average particle size of about 3 nm are supported on the same conductive carbon particles.
[0033] このそれぞれの触媒担持粒子と、 MEAと同様のプロトン伝導体と水とを混合し触媒 ペーストを作製する。このとき触媒担持粒子中のカーボンとプロトン導電体の重量比 は 1 : 1である。こうして作製したペーストそれぞれを、先に作製した膜 13の片面ずつ にスプレー法により塗布し、触媒層 14A、 14Bを作製する。その際、長さ 6. Ocm、幅 6. Ocmの穴を有するマスクを用いて、膜 13の中央部に 6. Ocm X 6. Ocmの範囲の 触媒層 14A、 14Bを形成する。以上のようにして不活性領域 11と触媒層 14A、 14B との重なりの長さが 1. Ommである MEA21が形成される。なお、触媒量はアノード側 、力ソード側それぞれ白金換算で約 lmg/cm2である。 Each of the catalyst-carrying particles, a proton conductor similar to MEA, and water are mixed to prepare a catalyst paste. At this time, the weight ratio of carbon and proton conductor in the catalyst-supporting particles Is 1: 1. Each of the pastes thus prepared is applied to one surface of the previously prepared film 13 by a spray method to form catalyst layers 14A and 14B. At this time, catalyst layers 14A and 14B in the range of 6. Ocm X 6. Ocm are formed in the center of the film 13 using a mask having a hole having a length of 6. Ocm and a width of 6. Ocm. As described above, the MEA 21 in which the overlap length of the inactive region 11 and the catalyst layers 14A and 14B is 1. Omm is formed. The amount of the catalyst is about lmg / cm 2 in terms of platinum on both the anode side and the power source side.
[0034] 次に、 MEA21の両面に、 6. 03cmX 6. 03cmの穴を持つ長さ 12cm、幅 12cm、 厚さ 300 /z mの枠体 17を設置する。その穴の中に 6. OOcm X 6. 00cm,厚み 360 mのカーボンペーパーからなる拡散層 15A、 15Bを設置する。さらに、深さ lmm、 幅 lmmで液体やガスの流れる溝が形成された厚み 4mmのカーボン板力 なるセパ レータ 18A、 18Bで挟み込みことで、図 2に示すような燃料電池（サンプル A)が得ら れる。 Next, a frame 17 having a length of 12 cm, a width of 12 cm, and a thickness of 300 / z m having a hole of 6.03 cm × 6.03 cm is installed on both sides of the MEA 21. Diffusion layers 15A and 15B made of carbon paper having a size of OOcm x 6000cm and a thickness of 360m are placed in the holes. Furthermore, a fuel cell (Sample A) as shown in Fig. 2 was obtained by sandwiching it between separators 18A and 18B, which are 4 mm thick and have a thickness of lmm and a width of lmm, in which grooves for liquid and gas flow are formed. Is received.
[0035] なお、運転時には、さらにこれらをセパレータ 18A、 18Bの外側から厚み 10mmの 金属板（図示せず)で挟み込み、ボルトを用いて 3kgZcm2の力で圧迫する。万力等 を用いて同様に圧迫してもよ 、。 During operation, these are further sandwiched between metal plates (not shown) having a thickness of 10 mm from the outside of the separators 18A and 18B, and pressed with a force of 3 kgZcm 2 using bolts. You can also use a vise or the like to do the same.
[0036] セパレータ 18A、 18Bと金属板にはそれぞれ、アノード側の燃料の吸入口 26と排 出口 27、力ソード側の空気等の酸化剤の吸入口 28と排出口 29が設けられている。 それぞれポンプを用いて、燃料と空気等が燃料電池に供給される。  [0036] Separators 18A and 18B and a metal plate are provided with a fuel inlet 26 and a discharge outlet 27 on the anode side, and a suction port 28 and a discharge port 29 for an oxidant such as air on the power source side, respectively. Fuel and air and the like are supplied to the fuel cell using the respective pumps.
[0037] サンプル B、 C、 D、 Eでは、スルホン基を除去する際の鉛板の大きさを変えることに より、スルホン基を除去した不活性領域 11と触媒層 14A、 14Bとの重なりの長さをサ ンプル Aと変えて MEAを形成する。それ以外はサンプル Aと同様に MEA21を作製 し、燃料電池を製造する。  [0037] In samples B, C, D, and E, the size of the lead plate at the time of removing the sulfone group was changed so that the inactive region 11 from which the sulfone group had been removed and the catalyst layers 14A and 14B overlapped. Change the length to sample A to form MEA. Other than that, MEA21 is made in the same way as Sample A, and a fuel cell is manufactured.
[0038] サンプル Bの作製時に用いる鉛板の大きさは 5. 94cm X 5. 94cmである。この場 合、不活性領域 11と触媒層 14A、 14Bとの重なりの長さは 0. 3mmである。サンプル Cの作製時に用いる鉛板の大きさは 5. 90cm X 5. 90cmである。この場合、不活性 領域 11と触媒層 14A、 14Bとの重なりの長さは 0. 5mmである。  [0038] The size of the lead plate used in the preparation of Sample B is 5.94cm x 5.94cm. In this case, the overlap length of the inactive region 11 and the catalyst layers 14A and 14B is 0.3 mm. The size of the lead plate used when preparing sample C is 5.90 cm X 5.90 cm. In this case, the overlap length of the inactive region 11 and the catalyst layers 14A and 14B is 0.5 mm.
[0039] サンプル Dの作製時に用いる鉛板の大きさは 5. OOcm X 5. OOcmである。この場 合、不活性領域 11と触媒層 14A、 14Bとの重なりの長さは 5mmである。サンプル E の作製時に用いる鉛板の大きさは 4. OOcm X 4. OOcmである。この場合、不活性領 域 11と触媒層 14A、 14Bとの重なりの長さは 10mmである。 [0039] The size of the lead plate used in the preparation of Sample D is 5. OOcm x 5. OOcm. In this case, the overlap length of the inert region 11 and the catalyst layers 14A and 14B is 5 mm. Sample E The size of the lead plate used in the preparation of the sample is 4. OOcm X 4. OOcm. In this case, the overlap length of the inert region 11 and the catalyst layers 14A and 14B is 10 mm.
[0040] なお、比較として、不活性領域 11と触媒層 14A、 14Bとの重なりの長さが Ommであ る MEAを形成し、サンプル Aと同様にしてサンプル Fの燃料電池を製造する。この場 合、スルホン基を除去する際の鉛板の大きさを 6. OOcm X 6. OOcmとする。サンプル Fの燃料電池の断面図を図 3に示す。  As a comparison, a MEA in which the inactive region 11 and the catalyst layers 14A, 14B overlap each other with a length of Omm is formed, and a fuel cell of Sample F is manufactured in the same manner as Sample A. In this case, the size of the lead plate when removing the sulfone group is 6. OOcm X 6. OOcm. FIG. 3 shows a cross-sectional view of the fuel cell of Sample F.
[0041] 次にサンプル A— Fの燃料電池の評価方法とその結果について説明する。アノード 側からは燃料として、 60°Cの加湿した水素を 0. 2LZminで、力ソード側からは酸ィ匕 剤として、 60°Cの加湿した空気を lLZminで供給する。燃料電池の温度は 60°Cで ある。いずれのサンプルでも初期の電流電圧特性は、 300mAZcm2の電流密度に 対し、 0. 6Vの起電力であり、ほぼ同じ特性である。これらのサンプルを 300mAZc m2の電流密度で連続して運転する。そして起電力が 0. 56Vを下回るまでの時間を 測定し、寿命の指標とする。図 4は、スルホン基を除去した不活性領域 11と触媒層 1 4A、 14Bとの重なりの長さに対してこの指標をプロットした結果を示している。 Next, the evaluation method of the fuel cells of Samples AF and the results thereof will be described. From the anode side, humidified hydrogen at 60 ° C is supplied as fuel at 0.2 LZmin, and from the power source side, humidified air at 60 ° C as oxidizing agent is supplied at 1 LZmin. The temperature of the fuel cell is 60 ° C. In all samples, the initial current-voltage characteristics are 0.6 V electromotive force at a current density of 300 mAZcm 2 , which is almost the same. Succession these samples at a current density of 300mAZc m 2 to operated. The time required for the electromotive force to fall below 0.56V is measured and used as an index of life. FIG. 4 shows the result of plotting this index with respect to the length of overlap between the inactive region 11 from which the sulfone group has been removed and the catalyst layers 14A and 14B.
[0042] 次にアノード側からは燃料として、 2molZLのメタノール水溶液を、 2mLZminで、 力ソード側からは酸化剤として空気を lLZminで供給する。燃料電池の温度は 60°C である。  Next, a 2 mol ZL aqueous methanol solution is supplied as a fuel from the anode side at 2 mL Zmin, and air as an oxidant is supplied at 1 L Zmin from the power source side. The temperature of the fuel cell is 60 ° C.
[0043] この条件で初期の電流電圧特性を調べる。 lOOmAZcm2の電流密度において、 サンプル Dとサンプル Eの起電力は 0. 35Vであり、サンプル Aでは 0. 345V、サンプ ル Cでは 0. 34V、サンプル Bでは 0. 33Vである。また比較のためのサンプル Fでは 0 . 32Vである。 Under these conditions, an initial current-voltage characteristic is examined. At a current density of lOOmAZcm 2 , the electromotive force of sample D and sample E is 0.35 V, 0.345 V for sample A, 0.34 V for sample C, and 0.33 V for sample B. In the sample F for comparison, the voltage is 0.32V.
[0044] 初期においては劣化の影響はないため、この違いは、クロスリーク量の差によるもの と考えられる。すなわち、スルホン基を除去した不活性領域と触媒層との重なりのな いサンプル Fに比べて、スルホン基を除去した不活性領域と触媒層との重なりが 0. 3 mmのサンプル Bはクロスリークの量が抑えられている。さらに重なりが 0. 5mmのサ ンプル C、 1mmのサンプル A、 5mmのサンプル Dの順にクロスリークの量が抑えられ ている。重なりが 10mmのサンプル Eではサンプル Dとほぼ同じ結果であることから、 ほぼ 5mmで効果が飽和して!/、ると考えられる。 [0045] これらのサンプルを lOOmAZcm2の電流密度で連続し、起電力が初期に対して 0 . 05V低下するまでの時間を測定し、寿命の指標とする。図 5は、スルホン基を除去 した不活性領域 11と触媒層 14A、 14Bとの重なりの長さに対してこの指標をプロット した結果を示している。 Since there is no influence of deterioration in the initial stage, this difference is considered to be due to the difference in the amount of cross leak. That is, as compared to Sample F, in which the inactive region from which the sulfone group was removed and the catalyst layer did not overlap, Sample B, in which the inactive region in which the sulfone group was removed and the catalyst layer overlapped 0.3 mm, was cross leaked. The amount of is suppressed. In addition, the amount of cross leak is reduced in the order of sample C with 0.5 mm overlap, sample A with 1 mm, and sample D with 5 mm. Since the result of sample E with an overlap of 10 mm is almost the same as that of sample D, it is considered that the effect is saturated at about 5 mm! /. [0045] succession these samples at a current density of LOOmAZcm 2, electromotive force is measured the time until reduction 0. 05V with respect to the initial, as an indicator of life. FIG. 5 shows the result of plotting this index with respect to the length of overlap between the inactive region 11 from which the sulfone group has been removed and the catalyst layers 14A and 14B.
[0046] 図 4、図 5より、不活性領域 11と触媒層 14A、 14Bとの重なりのないサンプル Fに比 ベて、不活性領域 11と触媒層 14A、 14Bとの重なりを有するサンプル A— Eは寿命 が長いことが分かる。サンプル Fでは、触媒層が存在する部分と触媒層の存在しない 部分の境目で、電解質膜のプロトン伝導性が変化している。そのため、中心部の活 性領域 12と、周囲の不活性領域 11との境目に存在する触媒層の状態が、中心部分 とは異なり、電流密度分布が不均一になっている。一方、サンプル A— Eでは、電解 質膜 13の活性領域 12におけるプロトン伝導性の不均一化が抑制されている。上記 の寿命の差は、このことに起因していると考えられる。  [0046] From FIGS. 4 and 5, as compared with Sample F in which the inactive region 11 and the catalyst layers 14A and 14B do not overlap, Sample A in which the inactive region 11 and the catalyst layers 14A and 14B overlap each other is shown in FIG. It can be seen that E has a long life. In sample F, the proton conductivity of the electrolyte membrane changes at the boundary between the portion where the catalyst layer exists and the portion where the catalyst layer does not exist. Therefore, the state of the catalyst layer existing at the boundary between the active region 12 at the center and the inactive region 11 around the center is different from that at the center, and the current density distribution is non-uniform. On the other hand, in Samples A to E, the non-uniformity of the proton conductivity in the active region 12 of the electrolyte membrane 13 is suppressed. It is considered that this difference in life is due to this.
[0047] さらに、サンプル A— Eでは、 MEA21とその周囲の枠体 17との間に存在する燃料 や空気と、活性領域 12の不活性領域 11との境目近傍は、図 3に示すサンプル Fの 構造に比較して触媒層 14A、 14Bにより隔離されている。そのため、活性領域 12の 不活性領域 11との境目近傍が、燃料や空気の流れの影響を受けない。そのため、 膜 13全体の保湿性能のバラツキが抑制され、電流密度分布の不均一化が抑えられ 、燃料電池としての寿命が向上している。  Further, in Samples A to E, the vicinity of the boundary between fuel and air existing between MEA 21 and surrounding frame 17 and the inactive region 11 of active region 12 is the same as Sample F shown in FIG. Compared to the structure of the above, they are isolated by the catalyst layers 14A and 14B. Therefore, the vicinity of the boundary between the active region 12 and the inactive region 11 is not affected by the flow of fuel or air. Therefore, variation in the moisturizing performance of the entire membrane 13 is suppressed, unevenness of the current density distribution is suppressed, and the life of the fuel cell is improved.
[0048] さらに燃料や空気の流れの影響が異なることは、クロスリーク量が異なることにも影 響している。水素のクロスリーク量は比較的小さいため、水素を燃料とする発電では サンプル Fとサンプル A— Eとで初期電圧に差は見られない。し力し、クロスリークしや すいメタノールを燃料とする場合、サンプル Fにくらべて、サンプル A— Eの初期電圧 は高ぐクロスリークが抑制されている。  [0048] Further, the difference in the influence of the fuel and air flows also affects the difference in the amount of cross leak. Since the amount of cross-leakage of hydrogen is relatively small, there is no difference in the initial voltage between sample F and samples A-E in power generation using hydrogen as fuel. When methanol is used as the fuel, which is susceptible to cross-leakage, the initial voltage of samples A to E is higher than that of sample F, and cross-leakage is suppressed.
[0049] クロスリークした燃料は力ソード側で酸ィ匕され発熱するため MEAの劣化が促進され る。すなわち、このようなクロスリークの違いも、寿命に影響する。このことも、図 4、図 5 でサンプノレ A— Eの寿命が向上している要因である。  [0049] The cross-leaked fuel is oxidized on the force sword side and generates heat, so that deterioration of the MEA is promoted. That is, such a difference in cross leak also affects the life. This is also the reason that the life of Sampnolle AE is improved in Figs.
[0050] なお、図 4、図 5より、不活性領域 11と触媒層 14A、 14Bとの重なりの長さ力 0. 5 mmのサンプル Cは、サンプル Fやサンプル Bに比べて著しく寿命が向上している。 すなわち、不活性領域 11と触媒層 14A、 14Bとの重なりの長さ（接触面 25の長さ）は 0. 5mm以上が望ましい。 1mm以上がさらに望ましい。 [0050] From Figs. 4 and 5, it can be seen from Fig. 4 and Fig. 5 that the life of sample C, in which the overlap region between the inactive region 11 and the catalyst layers 14A, 14B is 0.5 mm, is significantly improved as compared with the sample F and the sample B. are doing. That is, the length of the overlap between the inactive region 11 and the catalyst layers 14A and 14B (the length of the contact surface 25) is preferably 0.5 mm or more. 1 mm or more is more desirable.
[0051] 一方、接触面 25の長さが 5mmの場合と 10mmの場合とで寿命にほとんど差がな い。触媒は貴金属力 なり、不活性領域 11との重なりが大きいと、コストが増大するた め、実用的には接触面 25の長さは 5mm以下であることが望ましい。  On the other hand, there is almost no difference in the life between the case where the length of the contact surface 25 is 5 mm and the case where the length is 10 mm. Since the catalyst becomes a noble metal and has a large overlap with the inactive region 11, the cost increases. Therefore, in practice, the length of the contact surface 25 is desirably 5 mm or less.
[0052] また、触媒層 14A、 14Bは膜 13よりも面積が小さいが、これも上記と同様の理由と、 枠体 17で燃料電池をシールする理由による。なお、枠体 17を用いず、例えば接着 剤を拡散層に含浸させて構成してもよ ヽ。  The catalyst layers 14 A and 14 B have a smaller area than the membrane 13, but also for the same reason as described above, and for the reason that the fuel cell is sealed with the frame 17. Note that the frame 17 may not be used but may be configured by impregnating the diffusion layer with an adhesive, for example.
[0053] 以上の結果より、本実施の形態の構成によれば、長寿命でクロスリークの影響の少 な 、優れた燃料電池が得られる。  From the above results, according to the configuration of the present embodiment, it is possible to obtain an excellent fuel cell having a long life and little influence of cross leak.
[0054] なお、結果を詳細には示して!/ヽな 、が、サンプル Aにお!/、て、触媒層 14A、 14Bの それぞれの触媒量を白金換算で約 2mgZcm2として触媒層の厚みを変え、同様の 検討により寿命を測定している。また、触媒層中の触媒を担持したカーボンとプロトン 導電体との重量比を 1： 2などのように変化させて同様の検討により寿命を測定してい る。さらに、拡散層 15A、 15Bの厚みやサイズを変化させて同様の検討により寿命を 測定している。いずれの場合も、図 4、図 5の傾向は変わらない。このことから、不活 性領域 11と触媒層 14A、 14Bとの重なりの長さ力 反応の不均一化やクロスリークに よる劣化に最も効いている要因であると考えられる。なお、触媒層 14Aと不活性領域 11との重なりの長さと、触媒層 14Bと不活性領域 11との重なりの長さは異なって 、て も構わな!/ヽ。また不活性領域 11は膜 13の厚み方向全体に亘つて ヽなくてもょ 、。 [0054] The results are shown in detail! / ヽ, where the amount of catalyst in each of the catalyst layers 14A and 14B is about 2 mgZcm 2 in terms of platinum in Sample A. And the service life was measured by the same study. In addition, the life was measured by the same study while changing the weight ratio of the carbon carrying the catalyst and the proton conductor in the catalyst layer to 1: 2 or the like. Furthermore, the life is measured by the same study while changing the thickness and size of the diffusion layers 15A and 15B. In either case, the trends in Figures 4 and 5 remain the same. From this, it is considered that this is the most effective factor for the nonuniformity of the reaction of the overlap force between the inactive region 11 and the catalyst layers 14A and 14B and the deterioration due to cross leak. The length of the overlap between the catalyst layer 14A and the inactive region 11 and the length of the overlap between the catalyst layer 14B and the inactive region 11 may be different! / !. Further, the inactive region 11 may not be formed over the entire thickness direction of the film 13.
[0055] また、膜 13として、フッ素系以外にも、炭化水素系膜や、多孔質基材にプロトン導 電性物質を充填したものでも同様の効果が得られる。また、触媒層 14A、 14Bには MEAと同じプロトン伝導体を用いている力 異なるプロトン伝導体を用いてもよい。  [0055] In addition to the fluorine-based film 13 as the film 13, a hydrocarbon-based film or a material in which a porous substrate is filled with a proton-conductive substance can also provide the same effect. Further, the catalyst layers 14A and 14B may be made of the same proton conductor as the MEA but different in proton conductor.
[0056] なお、有機燃料として、本実施の形態ではメタノールを用いているが、膜 13を膨潤 させる度合いの大きい他の有機燃料でも同様の傾向を示す。一般に、有機燃料は膜 13を膨潤させる度合いが大きいため、アルコール類、エーテル類、メトキシ類含有ィ匕 合物などの有機燃料を使用したときに本発明が有効である。  In this embodiment, methanol is used as the organic fuel. However, other organic fuels having a high degree of swelling of the membrane 13 show the same tendency. In general, since the organic fuel has a large degree of swelling of the membrane 13, the present invention is effective when an organic fuel such as an alcohol, an ether, or a methoxy-containing compound is used.
産業上の利用可能性 [0057] 本発明による MEAは、寿命特性に優れた燃料電池に有用である。 Industrial applicability The MEA according to the present invention is useful for a fuel cell having excellent life characteristics.

Claims

請求の範囲 The scope of the claims
[1] 陽イオン交換基を有する活性領域と、前記活性領域の周囲に前記活性領域よりも陽 イオン交換基の単位体積あたりの数が少な 、不活性領域と、を有するプロトン伝導性 電解質膜と、  [1] A proton-conductive electrolyte membrane having an active region having a cation exchange group, and an inactive region around the active region, in which the number of cation exchange groups per unit volume is smaller than that of the active region. ,
前記プロトン伝導性電解質膜の第 1面に設けられた第 1触媒層と、  A first catalyst layer provided on a first surface of the proton conductive electrolyte membrane,
前記第 1面に対向する第 2面に設けられた第 2触媒層と、を備え、  A second catalyst layer provided on a second surface opposite to the first surface.
前記不活性領域は、前記第 1、第 2触媒層との間に挿入されている、  The inactive region is inserted between the first and second catalyst layers,
膜電極接合体。  Membrane electrode assembly.
[2] 陽イオン交換基を有する活性領域と、前記活性領域の周囲に前記活性領域よりも陽 イオン交換基の単位体積あたりの数が少な 、不活性領域と、を有するプロトン伝導性 電解質膜と、  [2] A proton-conductive electrolyte membrane having an active region having a cation exchange group, and an inactive region around the active region, in which the number of cation exchange groups per unit volume is smaller than that of the active region. ,
前記プロトン伝導性電解質膜の第 1面に設けられ、少なくとも前記活性領域を覆う第 1触媒層と、  A first catalyst layer provided on a first surface of the proton conductive electrolyte membrane and covering at least the active region;
前記第 1面に対向する第 2面に設けられ、少なくとも前記活性領域を覆う第 2触媒層 と、を備え、  A second catalyst layer provided on a second surface opposite to the first surface, and covering at least the active region.
前記第 1、第 2触媒層は前記活性領域よりも面積が大きい、  The first and second catalyst layers have a larger area than the active region,
膜電極接合体。  Membrane electrode assembly.
[3] 前記第 1、第 2触媒層は前記プロトン伝導性電解質膜より面積が小さい、  [3] The first and second catalyst layers have an area smaller than that of the proton conductive electrolyte membrane.
請求項 1、 2のいずれかに記載の膜電極接合体。  3. The membrane / electrode assembly according to claim 1.
[4] 前記不活性領域は、前記第 1、第 2触媒層と 0. 5mm以上の長さで重なっている、 請求項 1、 2のいずれかに記載の膜電極接合体。 4. The membrane electrode assembly according to claim 1, wherein the inert region overlaps the first and second catalyst layers with a length of 0.5 mm or more.
[5] 前記不活性領域は、前記第 1、第 2触媒層と lmm以上の長さで重なっている、 請求項 1、 2のいずれかに記載の膜電極接合体。 5. The membrane electrode assembly according to claim 1, wherein the inactive region overlaps the first and second catalyst layers with a length of 1 mm or more.
[6] 前記不活性領域は、前記第 1、第 2触媒層と 5mm以下の長さで重なっている、 請求項 1、 2のいずれかに記載の膜電極接合体。 6. The membrane electrode assembly according to claim 1, wherein the inactive region overlaps the first and second catalyst layers with a length of 5 mm or less.
[7] 前記不活性領域には、陽イオン交換基が存在しない、 [7] The inert region does not have a cation exchange group,
請求項 1、 2のいずれかに記載の膜電極接合体。  3. The membrane / electrode assembly according to claim 1.
[8] 請求項 1、 2のいずれかに記載の膜電極接合体と、 前記第 1触媒層の、前記プロトン伝導性電解質膜と反対側に設けられた第 1拡散層 と、 [8] The membrane electrode assembly according to any one of claims 1 and 2, A first diffusion layer provided on a side of the first catalyst layer opposite to the proton conductive electrolyte membrane;
前記第 2触媒層の、前記プロトン伝導性電解質膜と反対側に設けられた第 2拡散層 と、 A second diffusion layer provided on a side of the second catalyst layer opposite to the proton conductive electrolyte membrane;
前記第 1拡散層の、前記プロトン伝導性電解質膜と反対側に設けられ、燃料を供給 するための第 1吸入口と、燃料を排出するための第 1排出口とを設けられた第 1セパ レータと、 A first separator provided on the opposite side of the first diffusion layer from the proton conductive electrolyte membrane and provided with a first inlet for supplying fuel and a first outlet for discharging fuel; , And
前記第 2拡散層の、前記プロトン伝導性電解質膜と反対側に設けられ、酸化剤を供 給するための第 2吸入口と、酸化剤を排出するための第 2排出口とを設けられた第 2 セパレータと、を備えた、 The second diffusion layer was provided on the opposite side of the proton conductive electrolyte membrane, and provided with a second inlet for supplying an oxidant and a second outlet for discharging the oxidant. A second separator;
燃料電池。 Fuel cell.
前記燃料は、アルコール類、エーテル類、メトキシ類含有ィ匕合物の少なくともいずれ か一つを含む、 The fuel includes at least one of alcohols, ethers, and methoxy-containing conjugates.
請求項 8記載の燃料電池。 The fuel cell according to claim 8.
PCT/JP2004/016969 2003-11-25 2004-11-16 Membrane electrode assembly and fuel cell using same WO2005053071A1 (en)

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