JP2007287487A - Solid electrolyte fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid electrolyte fuel cell capable of simplifying cell assembly with CCM, and preventing a decrease in water absorption performance. <P>SOLUTION: In the solid electrolyte fuel cell, a separator and a gas diffusion layer are adhered with an adhesive at the outer edge of the gas channel of the separator for assembly. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a solid oxide fuel cell. In particular, the present invention relates to a solid electrolyte membrane excellent in water absorption and a method for producing the same.

  In recent years, in response to social demands and trends against the background of energy and environmental problems, fuel cells that can operate at room temperature and obtain high output density have attracted attention as mobile power sources and stationary power sources. A fuel cell is a clean power generation system in which the product of an electrode reaction is water in principle and has almost no adverse effect on the global environment. In particular, the polymer electrolyte fuel cell operates at a relatively low temperature, so it is used for various mobile objects from fuel cell vehicles to portable devices (for example, mobile phones, personal digital assistants, portable music players, notebook computers, etc.). Is expected as a power source.

  In general, the unit cell configuration of such a polymer electrolyte fuel cell has a structure in which an MEA is sandwiched between separators. The MEA is formed by sandwiching an electrolyte membrane (hereinafter also simply referred to as a membrane) between a pair of electrodes (an anode electrode and a cathode electrode). Here, the electrode usually has a structure in which an electrode catalyst layer (hereinafter also simply referred to as a catalyst layer) and a gas diffusion layer (hereinafter also simply referred to as GDL) are laminated. Specifically, the catalyst layer and the GDL are generally arranged on both sides of the membrane in this order. Furthermore, in the single cell (cell unit) configuration of the fuel cell, both sides of the membrane (in order to seal the outer periphery (edge) in order to prevent a minute leak or cross leak from the outer periphery (edge) of the single cell. A frame-like gasket layer is arranged on the outer peripheral portion of the portion where the electrode and GDL are formed on the cathode side and the anode side.

  Patent Document 1 discloses a technique for integrating a solid polymer electrolyte and GDL by sandwiching the solid polymer electrolyte between gas diffusion layers (GDL) and performing hot pressing.

Patent Document 2 describes a method of manufacturing a carbonaceous member for a fuel cell by bonding a porous electrode plate (GDL) to a carbon separator with a carbonized adhesive and firing at a high temperature of 600 ° C. is doing.
JP-A-3-295171 Japanese Patent Publication No. 3-20862

  However, as described in Patent Document 1, by performing hot pressing and integrating a gas diffusion layer (GDL: Gas Diffusion Layer) and an electrolyte membrane with a catalyst layer (CCM: Catalyst Coated Membrane), the water absorption of the membrane decreases. , Performance decreases. On the other hand, if the gas diffusion layer and the electrolyte membrane with the catalyst layer are not integrated, there is a problem that the cell assembly becomes complicated.

  Further, in the configuration described in Patent Document 2, since the adhesive is applied to the entire surface of the carbon separator, a substance that is scattered at a high temperature of 600 ° C. is used to prevent the adhesive from clogging the flow path of the carbon separator. The carbon separator is impregnated and dispersed during hot pressing to bond the GDL and the separator. Accordingly, the water absorption of the film is lowered by hot pressing, and the performance is lowered. On the other hand, if GDL and CCM are not integrated, there is a problem that the cell assembly becomes complicated.

  Accordingly, the present invention provides a solid electrolyte fuel cell (a polymer electrolyte fuel cell or a solid polymer electrolyte) that can prevent performance degradation without reducing the water absorption of the electrolyte membrane, and can further simplify the cell assembly. Type fuel cell).

  Accordingly, the present invention can achieve the above object by a solid oxide fuel cell characterized in that the separator and the GDL are assembled by bonding them with an adhesive at the outer edge part from the gas flow path of the separator.

  According to the present invention, in the solid electrolyte fuel cell, the separator and the GDL are bonded to each other by the adhesive at the outer edge portion from the gas flow path of the separator, and the cell is assembled with the CCM. The cell assembling process can be simplified and a high quality fuel cell can be provided.

  The solid oxide fuel cell according to the present invention is characterized in that a separator and GDL are bonded and assembled. By lightly adhering GDL to the separator side when assembling the cells, it is excellent in that the cell assembly with the CCM can be simplified, a high-quality battery can be provided, and performance degradation can be prevented.

  Hereinafter, preferred embodiments of the fuel cell of the present invention will be described with reference to FIGS.

  In order to describe the present invention, FIG. 1 shows a cross-section of a technical example of a conventional fuel cell, and FIGS. 2 to 5 show the configuration of the fuel cell of the present invention. FIG. 6 shows the battery characteristics of the present invention. Embodiments and examples of the present invention will be outlined below with reference to the drawings.

[I] First Embodiment FIG. 1 is a configuration diagram of a conventional fuel cell. In the conventional unit fuel cell (fuel cell) 10 of FIG. 1, a membrane electrode assembly (MEA) in which an anode (fuel electrode) and cathode (air electrode) catalyst layers 111a and 111b are bonded to both surfaces of an electrolyte membrane 100. 110 is provided. Anodes and cathodes GDL 112 a and 112 b such as carbon paper and carbon cloth are disposed on both outer sides of the MEA 110. Dense and conductive anode and cathode separators 120a and 120b are disposed on both outer surfaces. Hydrogen is contained through anode-side hydrogen-containing gas (H ₂ gas) flow path (groove) 121a and cathode-side oxygen-containing gas (air gas) flow path (groove) 121b provided in the anode and cathode separators 120a and 120b. A gas (hereinafter simply abbreviated as H ₂ ) and an oxygen-containing gas (hereinafter simply abbreviated as Air) are supplied to the anode-side and cathode-side GDLs 112a and 112b and the catalyst layers 111a and 111b, respectively. Gaskets 130a and 130b are disposed between the outer periphery of the electrolyte membrane 100 and the outer periphery of the separators 120a and 120b (anode-side and cathode-side protective sheets 150a and 150b) to prevent the gas from leaking to the outside. Has been.

  FIG. 2 is a cross-sectional view showing the configuration of the fuel cell according to the first embodiment of the present invention, and is a top view of the whole (the positional relationship between the flow path, the gasket, and the bonding portion is clarified through the separator). 3) is shown in FIG.

As shown in FIGS. 2 and 3, the basic fuel cell configuration of the unit fuel cell (fuel cell) 10 according to the first embodiment of the present invention is the same as that of the conventional fuel cell of FIG. However, in the present invention, the anode and cathode bonding portions 140a and 140b are further bonded so that the anode and cathode GDLs 112a and 112b are bonded to the outside of the H ₂ gas channel 121a and the Air gas channel 121b of the anode and cathode separators 120a and 120b, respectively. It is characterized by being provided. Hereinafter, each component is demonstrated centering on the said adhesion part. In FIG. 3, since the basic configuration on the anode side and the cathode side is the same, the separator 120, the gas flow path (groove) 121, the gasket 130, and the bonding portion 140 are shown without distinction between the anode side and the cathode side. . Also in the explanation of each of the constituent elements below, the catalyst layer 111, GDL 112, separator 120, gas flow path (groove) 121, gasket 130, It is represented as an adhesive part 140, a protective sheet 150, and a guide 160.

(1) Bonding part The bonding part 140 is formed for the purpose of simplifying the cell assembly with the CCM (MEA) 110 and preventing performance degradation by lightly adhering the GDL 112 to the separator 120 side during cell assembly. It will be.

  The bonding part 140 is formed by bonding the GDL 112 and the separator 120 (lamination surface) for the purpose of forming the bonding part, and the characteristics of the gas flow path 121, the gasket 130, and the constituent members of the protective sheet 150. The position is not particularly limited as long as the position is not impaired.

  Specifically, as shown in FIG. 2, the unit fuel cell (fuel cell) 10 is bonded to the anode side GDL 112a and the separator 120a, the cathode side GDL 112b and the separator 120b in the thickness direction. It is particularly desirable to form the bonding portions 140a and 140b on the cell from the viewpoint of simplifying the cell assembly. That is, it is desirable that the bonding portion 140 between the separator 120 and the GDL is formed between the anode separator 120a and the anode GDL 112a and between the cathode separator 120b and the cathode GDL 112b. This is because the cell assembling process can be further simplified because the bonding surface is formed on each of the anode and cathode separators. However, only one of the two sides is more effective in simplifying cell assembly and preventing performance degradation than in the past.

  In addition, the arrangement (adhesion location) in the in-plane direction of each of the anode and the cathode of the adhesion part 140 is not particularly limited, and the whole or part of the outside (outer peripheral part) of the gas flow path 121 of the separator 120. The bonding portion 140 may be formed on the substrate. Preferably, as shown in FIG. 3, the separator 120 and the GDL 112 are integrated so that the GDL 112 and the separator 120 that are bonded and fixed are integrated when the cell is assembled with the CCM (MEA) 120, and the handling is excellent. It is desirable that the bonding portion 140 is at an outer edge portion than the gas flow path 121 of the separator 120. Thereby, in the solid electrolyte fuel cell, since the adhesion surface between the separator 120 and the GDL 112 is outside the gas flow path 121, it is excellent in that the assembly can be performed without obstructing the gas flow. Specifically, it is desirable to form a plurality of locations outside the gas flow passage 121 of the separator 120 (outer edge portion or outer peripheral portion), preferably outside the gas flow passage 121 on the four sides of the separator 120. This is because when the joined body of the GDL 112 and the separator 120 is handled, it is possible to more effectively prevent the GDL 112 and the separator 120 from being displaced due to peeling of the bonding portion 140 even if vibration, deflection or twist is applied. It is. However, even if there is only one bonding portion 140, the purpose may be sufficiently achieved depending on how it is handled, such as when it can be moved and transported relatively stably from bonding to cell assembly.

  Moreover, each arrangement | positioning (each adhesion location) of the adhesion part 140 at the time of adhere | attaching and fixing GDL112 and the separator 120 may be surface adhesion as shown in FIG. 3, and point adhesion may be sufficient as it. Here, the surface bonding and the point bonding are, for example, a surface bonding in which the bonding portion 140 is continuous over almost the entire region from one end to the other end of one side of the separator 120 (see FIG. 3B). When two or more adhesive portions 140 are formed in a discontinuous manner (arrangement) from one end of the side to the other end, point bonding is used (see FIG. 3A). Preferably, the bonding location between the separator and the GDL is a plurality of surface bonding or point bonding. It is excellent in that the amount of the adhesive to be used can be reduced by using a plurality of surface bonds or point bonds as the bonding location. However, it is not particularly limited, for example, an adhesive may be applied to the entire surface (outer edge portion or outer peripheral portion) of the gas flow path 121 of the separator 120.

  Further, the thickness of the adhesive between the separator 120 and the GDL 112 (adhesive portion 140) is that the adhesive is impregnated in the GDL 112 if the adhesive amount is too large, and the gas diffusion property may be inhibited. What is necessary is just to determine suitably considering that there exists a possibility of causing peeling of adhesion | attachment by lack. Specifically, it is 0.1 mm or less, desirably 0.05 mm or more and 0.1 mm or less. In addition, the thickness of the said adhesive agent shall say the thickness at the time of apply | coating an adhesive agent on GDL. In addition, the thickness of the adhesive does not include a portion impregnated in the GDL 112. The said adhesion amount shall say the application amount of the adhesive agent per unit area. In addition to the thickness of the adhesive, when applying the adhesive and pasting the separator and the GDL, GDL is used from the viewpoint of preventing intrusion into the gas flow path and gasket installation surface due to the spread of the adhesive in the in-plane direction. It is desirable to determine the coating amount and coating position on the (or separator).

  The adhesive that can be used for the bonding portion 140 is not particularly limited as long as it can effectively exert the effects of the present invention. For example, a hot melt adhesive such as a thermoplastic elastomer, an acrylic adhesive, an epoxy adhesive, a polyester adhesive, an olefin adhesive such as a polyolefin (for example, polypropylene), or the like can be used. The adhesive used for bonding the separator and the GDL is preferably an epoxy adhesive. By using an epoxy-based adhesive for the adhesive, it has good adhesion to the separator to be bonded and has excellent heat resistance, so it can prevent elution of the adhesive during high temperature use and make it difficult to peel off. is there. In addition, it is excellent in vibration resistance and shock resistance against vibrations and shocks to the adhesion part applied during driving of the fuel cell and driving of the vehicle in which the fuel cell is mounted. It is also excellent in that it can be demonstrated.

  As a method for applying an adhesive to a bonding portion (bonding portion 140) between the separator 120 and the GDL 112, a roll coating method, a curtain coating method, an extrusion coating method, a spin coating method, a dip coating method, a bar coating method, a spray. The coating method, slide coating method, printing coating method and the like can be used. Preferably, the adhesive applied to the bonding portion (bonding portion 140) is formed by using a spray coating method. This is because by using the spray coating method, the adhesion area and the adhesion amount can be easily controlled, and the adhesive can be applied at an accurate position.

(2) Electrolyte membrane 100
The electrolyte membrane 100 used in the fuel cell of the present invention is not particularly limited, and a membrane made of a known polymer electrolyte can be used, but any member having at least high proton conductivity may be used. The polymer electrolyte that can be used in this case is roughly classified into a fluorine-based electrolyte that contains fluorine atoms in the whole or a part of the polymer skeleton and a hydrocarbon-based electrolyte that does not contain fluorine atoms in the polymer skeleton. Specifically, the polymer skeleton is a fluorine polymer in which all or part of the polymer skeleton is fluorinated and has an ion exchange group, or the polymer skeleton is a hydrocarbon polymer that does not contain fluorine and has an ion exchange group. An electrolyte provided with, for example.

Examples of the ion-exchange group is not particularly _{limited, -SO 3 H, -COOH, -PO} (OH) 2, -POH (OH), - SO 2 NHSO 2 -, - Ph (OH) (Ph represents a phenyl group A cation exchange group such as —NH ₂ , —NHR, —NRR ′, —NRR′R ″ ⁺ , —NH ₃ ^{+ and the} like (R, R ′, R ″ represent an alkyl group, cycloalkyl Anion exchange groups such as a group, an aryl group, and the like.

  Specific examples of the electrolyte that is a fluorine-based polymer and has an ion exchange group include Nafion (registered trademark, manufactured by DuPont), Aciplex (registered trademark, manufactured by Asahi Kasei Co., Ltd.), and Flemion (registered trademark, Asahi Glass). Perfluorocarbon sulfonic acid polymer, polytrifluorostyrene sulfonic acid polymer, perfluorocarbon phosphonic acid polymer, trifluorostyrene sulfonic acid polymer, ethylenetetrafluoroethylene-g-styrene sulfonic acid polymer, Suitable examples include ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene-g-polystyrene sulfonic acid polymer, and polyvinylidene fluoride-g-polystyrene sulfonic acid polymer.

  Specific examples of the hydrocarbon polymer having an ion exchange group include a polysulfone sulfonic acid polymer, a polyether ether ketone sulfonic acid polymer, a polybenzimidazole alkyl sulfonic acid polymer, and a polybenzimidazole. Suitable examples include alkylphosphonic acid polymers, cross-linked polystyrene sulfonic acid polymers, and polyether sulfone sulfonic acid polymers.

  Since the material of the electrolyte membrane 1 has high ion exchange ability and is excellent in chemical durability and mechanical durability, it is preferable to use an electrolyte which is the above-mentioned fluorine-based polymer and has an ion exchange group. Of these, Nafion (registered trademark, manufactured by DuPont), Aciplex (registered trademark, manufactured by Asahi Kasei Co., Ltd.) and the like can be more preferably used.

  In addition, various Nafion (registered trademark of DuPont) manufactured by DuPont and perfluorosulfonic acid membranes represented by Flemion, ion exchange resins manufactured by Dow Chemical, ethylene-tetrafluoroethylene copolymer resin membrane, trifluoro Fluoropolymer electrolytes such as resin membranes based on styrene, hydrocarbon resin membranes with sulfonic acid groups, and other commonly available solid polymer electrolyte membranes and polymer microporous membranes A membrane impregnated with a liquid electrolyte, a membrane in which a porous body is filled with a polymer electrolyte, or the like may be used. Alternatively, the electrolyte membrane may be made of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), or the like in addition to the above-described fluorine-based polymer electrolyte or a membrane made of a hydrocarbon resin having a sulfonic acid group. You may use what formed the porous thin film impregnated with electrolyte components, such as phosphoric acid and an ionic liquid.

  The thickness of the electrolyte membrane 1 may be appropriately determined in consideration of the characteristics of the obtained fuel cell. Preferably it is 5-300 micrometers, More preferably, it is 10-200 micrometers, Most preferably, it is 15-150 micrometers. The thickness of the electrolyte membrane is preferably 5 μm or more from the viewpoint of strength during film formation and durability during operation of the fuel cell, and is preferably 300 μm or less from the viewpoint of output characteristics during operation of the fuel cell.

  The size of the electrolyte membrane may be appropriately determined in consideration of the characteristics of the obtained fuel cell. At this time, the outer periphery of the electrolyte membrane may be replaced with a gasket structure (not shown). In this case, it is excellent in that the film can be saved. For example, the price of a fuel cell for an automobile fuel cell is said to be 100 million yen or more, and it is said that it is difficult to achieve a price comparable to that of a current gasoline engine car only by the cost reduction effect by mass production. . Therefore, development of parts and structures that contribute to cost reduction as well as improvement of fuel cell performance has become an important theme. This is one of the problems that can be said with respect to the membrane constituting the fuel cell. In particular, in the fluorine-based resin membrane that is one of the high-performance membranes, cost reduction is a major theme. Therefore, replacing the membrane in the edge region of MEA with a gasket structure that can use the existing inexpensive resin sheets such as PEN, PET, PTFE, etc. makes it possible to obtain a significant cost reduction effect. It is said that.

  In the present invention, the constituent member containing the electrolyte component interposed between the oxygen electrode and the fuel electrode of the fuel cell is referred to as the electrolyte membrane, but is not limited to the name. From the viewpoint of the purpose of use used in the fuel cell, for example, even when it is referred to as an electrolyte layer or an electrolyte, it may be included in the electrolyte membrane referred to in the present invention. The same applies to the other component requirements, and the identity is not limited to the name, but the identity may be determined in light of the purpose of use.

(3) Catalyst layer 111
As shown in FIG. 1, the size of the catalyst layer on either the anode or cathode side is larger than the size of the other catalyst layer, and the end portions of the catalyst layer do not overlap in the thickness direction. Is desirable. In particular, it can be said that it is desirable to make the size of the anode catalyst layer larger than the size of the CASED catalyst layer. This is because it is excellent in the point of corrosion of the cathode catalyst in the start / stop operation / continuous operation and the suppression of decomposition of the electrolyte membrane during the OCV holding assuming the idling stop operation.

  As the structure of the catalyst layer bonded to both surfaces (air electrode side and fuel electrode side) of the electrolyte membrane, respectively, (i) a catalyst material in which catalyst particles are supported on a conductive carrier (hereinafter also referred to as an electrode catalyst). And (ii) an electrolyte having proton conductivity (hereinafter also referred to as a binder).

(I) Electrocatalyst The electrode catalyst is obtained by supporting (a) catalyst particles on (b) a conductive carrier.

(A) Catalyst Particles The components of the catalyst particles used in the cathode catalyst layer are not particularly limited as long as they have a catalytic action for the oxygen reduction reaction, and known catalysts can be used in the same manner. The components of the catalyst particles used in the anode catalyst layer are not particularly limited as long as they have a catalytic action for the hydrogen oxidation reaction, and known catalysts can be used in the same manner.

  Specific examples of the components of the catalyst particles supported on these conductive carriers include, for example, platinum, ruthenium, iridium, rhodium, palladium, osmium, tungsten, lead, iron, chromium, cobalt, nickel, manganese, vanadium, One selected from the group consisting of molybdenum, gallium, aluminum, silicon, phosphorus, titanium, copper, germanium, selenium, zirconium, tin, antimony, tellurium, rhenium, gold and bismuth, or at least selected from this group Two types of alloys can be used. Of these, those containing at least platinum are preferably used in order to improve power generation characteristics, durability, catalytic activity, poisoning resistance to carbon monoxide, heat resistance, and the like. Specifically, platinum, a platinum-iron alloy, a platinum-cobalt alloy, a platinum-nickel alloy, a platinum-molybdenum alloy, a platinum-ruthenium alloy, or the like can be given. The composition of the alloy is preferably 30 to 90 atomic% for platinum and 10 to 70 atomic% for the metal to be alloyed, depending on the type of metal to be alloyed. The composition of the alloy when the alloy is used as a cathode catalyst varies depending on the type of metal to be alloyed and can be appropriately selected by those skilled in the art, but platinum is 30 to 90 atomic%, and other metals to be alloyed are 10 It is preferable to set it to -70 atomic%. In general, an alloy is a generic term for a metal element having one or more metal elements or non-metal elements added and having metallic properties. The alloy structure consists of a eutectic alloy, which is a mixture of the component elements as separate crystals, a component element completely melted into a solid solution, and a component element composed of an intermetallic compound or a compound of a metal and a nonmetal. There is what is formed, and any may be used in the present application. At this time, the catalyst component used in the cathode catalyst layer and the catalyst particle component used in the anode catalyst layer can be appropriately selected from the above. In the following description, unless otherwise specified, the descriptions of the components of the catalyst particles for the cathode catalyst layer and the anode catalyst layer have the same definition for both, and are collectively referred to as “catalyst components”. However, the catalyst components for the cathode catalyst layer and the anode catalyst layer do not need to be the same, and are appropriately selected so as to exhibit the desired action as described above.

  The shape and size of the catalyst particles are not particularly limited, and the same shape and size as known catalyst particles can be used, but the catalyst particles are preferably granular. At this time, the smaller the average particle size of the catalyst particles, the higher the effective electrode area in which the electrochemical reaction proceeds, so that the oxygen reduction activity is preferably high. However, if the average particle size is too small, the oxygen reduction activity is actually rather small. A decreasing phenomenon is observed. Accordingly, the average particle size of the catalyst particles is preferably 1 to 30 nm, more preferably 1.5 to 20 nm, even more preferably 2 to 10 nm, and particularly preferably 2 to 5 nm. It is preferably 1 nm or more from the viewpoint of easy loading and catalytic activity corresponding to the specific surface area. From the viewpoint of catalyst activity and catalyst utilization, it is preferably 30 nm or less. The “average particle diameter of the catalyst particles” in the present invention is the average value of the particle diameter of the catalyst particles obtained from the crystallite diameter or transmission electron microscope image obtained from the half width of the diffraction peak of the catalyst component in X-ray diffraction. Can be obtained by obtaining.

(B) Conductive carrier The conductive carrier is not particularly limited as long as it has a specific surface area for supporting the catalyst particles in a desired dispersed state and has electronic conductivity that functions as a current collector. . Examples of the material of the conductive carrier include carbon black such as ketjen black ^TM or acetylene black, graphite such as activated carbon, coke, natural graphite or artificial graphite, mesocarbon microbeads, glassy carbon powder, and carbon nanotube. Carbon particles whose main component is carbon are preferred. In the present invention, “the main component is carbon” refers to containing a carbon atom as a main component, and is a concept including both a carbon atom only and a substantially carbon atom. In some cases, elements other than carbon atoms may be included in order to improve the characteristics of the fuel cell. In addition, being substantially composed of carbon atoms means that mixing of impurities of about 2 to 3% by mass or less is allowed.

The BET specific surface area of the conductive carrier may be a specific surface area sufficient to carry the catalyst component in a highly dispersed state, but is preferably 20 to 1600 m ² / g, more preferably 80 to 1200 m ² / g. Is good. When the specific surface area is 20 m ² / g or more, the dispersibility of the catalyst component and the polymer electrolyte in the conductive carrier is improved, which is excellent in that sufficient power generation performance can be obtained. On the other hand, when it is 1600 m ² / g or less, the catalyst component and the polymer electrolyte are excellent in that a high effective utilization rate can be effectively maintained.

  Further, the size of the conductive carrier is not particularly limited, but from the viewpoint of controlling the ease of loading, the catalyst utilization, and the thickness of the catalyst layer within an appropriate range, the average primary particle size of the conductive carrier. Is preferably 2 nm to 1 μm, more preferably 5 to 200 nm, and particularly preferably 10 to 100 nm. The average primary particle diameter is preferably 2 nm or more from the viewpoint of forming an effective conductive network, and 1 μm or less is preferable from the viewpoint that the thickness of the catalyst layer can be controlled within an appropriate range.

  In the electrode catalyst in which catalyst particles are supported on the conductive support, the supported amount of catalyst particles is 5 to 80% by mass, preferably 10 to 75% by mass, more preferably 15 to 70%, based on the total amount of the electrode catalyst. It is good to set it as the mass%, especially 30-70 mass%. When the supported amount is 80% by mass or less, it is possible to effectively maintain an excellent degree of dispersion of the catalyst component on the conductive support, and to effectively improve the power generation performance corresponding to the increase in the supported amount. There is an advantage that it can be expressed and high durability can be maintained. Further, when the supported amount is 5% by mass or more, the catalyst activity per unit mass is excellent, and desired power generation performance corresponding to the supported amount can be obtained. Therefore, it is excellent in that the carrying amount design for ensuring the desired battery performance can be made relatively easily. The amount of the catalyst component supported can be examined by inductively coupled plasma emission spectroscopy (ICP).

  The catalyst particles can be supported on the conductive support by a known method. For example, known methods such as impregnation method, liquid phase reduction support method, evaporation to dryness method, colloid adsorption method, spray pyrolysis method, reverse micelle (microemulsion method) can be used. Alternatively, a commercially available electrode catalyst may be used.

(Ii) Electrolyte (binder)
The cathode catalyst layer / anode catalyst layer (hereinafter also simply referred to as “catalyst layer”) of the present invention contains an electrolyte in addition to the electrode catalyst. The electrolyte having proton conductivity contained in the catalyst layer preferably covers at least a part of the electrode catalyst so as to form a three-layer interface. Thereby, not only can proton conductivity be improved, but also the electrode structure can be stably maintained, and the electrode performance can be enhanced. The electrolyte is not particularly limited, and the same polymer electrolyte as that used for the membrane can be used. The electrolyte used for the membrane and the electrolyte used for each catalyst layer may be the same or different, but from the viewpoint of improving the adhesion between each catalyst layer and the membrane, the same one is used. Is preferred.

The electrolyte is not particularly limited and a known one can be used, but any member having at least high proton conductivity may be used. Electrolytes that can be used in this case are broadly classified into fluorine-based electrolytes containing fluorine atoms in all or part of the polymer skeleton and hydrocarbon-based electrolytes not containing fluorine atoms in the polymer skeleton. That is, the polymer electrolyte described in the above-mentioned section of the electrolyte membrane can be preferably used. For example, a perfluorosulfonic acid polymer proton conductor such as a Nafion solution, a hydrocarbon polymer compound doped with an inorganic acid such as phosphoric acid, an organic partially substituted with a proton conductor functional group / Inorganic hybrid polymer, ion exchange resin made of proton conductor impregnated with phosphoric acid solution or sulfuric acid solution in polymer matrix. Specific examples of perfluorosulfonic acid polymer proton conductors include not only polymers composed of only carbon atoms and fluorine atoms, but also oxygen atoms if all hydrogen atoms are replaced with fluorine atoms. and the _like, CF 2 = polymerized units based on CF ₂ and _{CF 2 = CF- (OCF 2 CFX} ) m -O p - (CF 2) n -SO 3 polymerized units (in the formula based on H, X is fluorine An atom or a trifluoromethyl group, m is an integer of 0 to 3, n is an integer of 1 to 12, and p is 0 or 1.).

  Specific examples of the fluorine electrolyte include perfluorocarbon sulfonic acids such as Nafion (registered trademark, manufactured by DuPont), Aciplex (registered trademark, manufactured by Asahi Kasei Co., Ltd.), and Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.). Polymer, polytrifluorostyrene sulfonic acid polymer, perfluorocarbon phosphonic acid polymer, trifluorostyrene sulfonic acid polymer, ethylene tetrafluoroethylene-g-styrene sulfonic acid polymer, ethylene-tetrafluoroethylene copolymer, polyvinylidene A preferred example is a fluoride-perfluorocarbon sulfonic acid-based polymer.

  Specific examples of the hydrocarbon electrolyte include polysulfone sulfonic acid, polyaryl ether ketone sulfonic acid, polybenzimidazole alkyl sulfonic acid, polybenzimidazole alkyl phosphonic acid, polystyrene sulfonic acid, polyether ether ketone sulfonic acid, polyphenyl. A suitable example is sulfonic acid.

  The polymer electrolyte preferably contains a fluorine atom because of its excellent heat resistance and chemical stability. Among them, Nafion (registered trademark, manufactured by DuPont), Aciplex (registered trademark, manufactured by Asahi Kasei Co., Ltd.) Fluorine electrolytes such as Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.) are preferred.

  The mass ratio of the electrolyte to the conductive carrier is preferably 0.3: 1 to 1.3: 1, more preferably 0.5: 1 to 1.1: 1 in order. From the viewpoint of good ionic conductivity in the catalyst layer, the mass ratio of the polymer electrolyte as the electrolyte component to the conductive carrier mass is preferably 0.3 times or more, and the catalyst layer is 1.3 times or less. It is preferable in terms of gas diffusion and water discharge.

  The catalyst layer may further contain a water repellent polymer and other various additives. By containing the water-repellent polymer, the water repellency of the resulting catalyst layer can be increased, and water generated during power generation can be quickly discharged. The mixing amount of the water-repellent polymer can be appropriately determined within a range that does not affect the function and effect of the present invention. Examples of the water-repellent polymer include polypropylene, polyethylene, or polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyhexafluoropropylene, or a copolymer of these monomers (for example, tetrafluoroethylene-hexa Fluorine polymer materials such as a fluoropropylene copolymer can be used. Examples of other various additives include, but are not limited to, various antioxidants such as phosphorus antioxidants and phenolic antioxidants.

  Although the thickness of the catalyst layer in this invention is not specifically limited, 0.1-100 micrometers is preferable, More preferably, it is 1-20 micrometers. When the thickness of the catalyst layer is 0.1 μm or more, it is preferable in that a desired power generation amount can be obtained, and when it is 100 μm or less, it is preferable in that a high output can be maintained.

(4) GDL112
The GDL 112 is disposed on the anode and cathode catalyst layers 111a and 111b on both sides of the electrolyte membrane 100, respectively. Specifically, it can be obtained by sandwiching the MEA (membrane + catalyst layer) 110 with the GDL 112 integrated with the separator 120. Conventionally, the MEA (membrane + catalyst layer) 110 is further sandwiched between GDLs 112, and this is sandwiched and joined by hot pressing, so that the water absorption of the membrane is reduced, and the performance is lowered. The present invention is excellent in that the cell assembly with the CCM (MEA) 110 can be easily performed without performing such hot pressing.

  In the present invention, the size (size relationship) of the anode GDL 112a and the cathode 112b on both sides of the electrolyte membrane 100 may be the same area (size) as shown in FIG. The area may be smaller than the area of the cathode GDL 112b. Or conversely, the area of the anode GDL 112a may be larger than the area of the cathode GDL 112b. Preferably, the anode GDL 112a preferably has a smaller area than the cathode GDL 112b.

  As for the positional relationship between the GDL 112 and the catalyst layer 111, the GDL 112 and the catalyst layer 111 may be formed in the same area so that the outer peripheral end faces thereof are flush with each other, or the outer peripheral end faces may be different from each other. Alternatively, the area of the catalyst layer 111 may be increased. Or you may form so that the area of the catalyst layer 111 may become smaller than GDL112 conversely (refer FIG. 2, 4). In particular, when the protective sheet layer 150 having adhesiveness is provided as a part of the gasket structure on the outer peripheral portion (outer peripheral portion than the catalyst layer 111) on both surfaces of the electrolyte membrane 100, the protective sheet layer 150 is also in contact with the GDL 112. Thus, it is desirable to make the catalyst layer 111 small (see FIGS. 2 and 4).

  The GDL 112 is not particularly limited, and known materials can be used in the same manner. For example, (G) based on a sheet-like material having conductivity and porosity such as a carbon woven fabric, a paper-like paper body, a felt, and a non-woven fabric. What is used as a material. The GDL 112 has (ii) a carbon particle layer (not shown) made of an aggregate of carbon particles containing a water repellent on the GDL (base material) of (i) in order to further improve water repellency. It may be a thing.

(I) GDL (base material)
In the fuel cell of the present invention, the thickness of the catalyst layer 111, the GDL 112, and the electrolyte membrane 100 is desirably thin to improve the diffusibility of the fuel gas, but if it is too thin, sufficient electrode output cannot be obtained. . Therefore, it may be determined as appropriate so as to obtain a fuel cell having desired characteristics. From this viewpoint, the thickness of the GDL (base material) may be appropriately determined in consideration of the characteristics of the obtained GDL (which may include MIL described later), but may be about 30 to 500 μm. . A thickness of GDL (base material) of 30 μm or more is desirable because sufficient mechanical strength can be obtained. On the other hand, if the thickness of the GDL (base material) is 500 μm or less, the distance through which gas or water permeates is not too long, and good gas diffusibility and water diffusibility (drainage) can be obtained. It is excellent in that it can

  The GDL 112 preferably contains a water repellent in the GDL (base material) for the purpose of further improving water repellency and preventing a flooding phenomenon. Although it does not specifically limit as said water repellent, It is fluorine-type, such as a polytetrafluoroethylene (PTFE), a polyvinylidene fluoride (PVDF), a polyhexafluoropropylene, a tetrafluoroethylene-hexafluoropropylene copolymer (FEP). Examples thereof include polymer materials, polypropylene, and polyethylene.

(Ii) Carbon particle layer (also simply referred to as MIL)
The MIL is formed as a MIL composed of an aggregate of carbon particles containing a water repellent on the GDL (base material) in order to further improve the water repellency. Specifically, the MIL formation surface is disposed so as to contact the catalyst layer, and the GDL (base material) surface is disposed so as to contact the separator.

  The carbon particles are not particularly limited, and may be conventional ones such as carbon black, graphite, and expanded graphite. Of these, carbon blacks such as oil furnace black, channel black, lamp black, thermal black, and acetylene black are preferred because of their excellent electron conductivity and large specific surface area. The particle size of the carbon particles is preferably about 10 to 100 nm. Thereby, while being able to obtain the high drainage property by capillary force, it becomes possible to improve contact property with a catalyst layer.

  Examples of the water repellent used for the MIL include the same water repellents as those described above used for the substrate. Of these, fluorine-based polymer materials are preferably used because of their excellent water repellency and corrosion resistance during electrode reaction.

  In the MIL, the mixing ratio of the carbon particles to the water repellent may be insufficient to obtain water repellency as expected when there are too many carbon particles. If there are too many water repellents, sufficient electron conductivity can be obtained. There is no fear. Considering these, the mixing ratio of the carbon particles and the water repellent in the carbon particle layer is preferably about 90:10 to 40:60 in terms of mass ratio.

  The thickness of the MIL may be appropriately determined in consideration of the water repellency of the entire GDL 112 to be obtained.

  When the GDL contains a water repellent, a general water repellent treatment method may be used. For example, after immersing the base material used for GDL in the dispersion liquid of a water repellent, the method of heat-drying in oven etc. is mentioned.

  When MIL is formed on a transfer mount in GDL, carbon particles, water repellent, etc. are dispersed in a solvent such as water, alcohol solvents such as perfluorobenzene, dichloropentafluoropropane, methanol, ethanol and the like. The slurry is prepared by applying the slurry onto a transfer mount and dried, or the slurry is once dried and pulverized to form a powder, and this is applied to the gas diffusion layer. Good. Then, it is preferable to heat-process at about 250-400 degreeC using a muffle furnace or a baking furnace.

  The positional relationship between the MIL, GDL (excluding MIL) and the catalyst layer is the same as that of the GDL and the catalyst layer, and the same area may be used so that the end faces of the outer peripheral portions are flush with each other. Good. Preferably, on the side where the adhesive layer is provided, it is desirable to make the catalyst layer small so that the adhesive layer is in contact with MIL or GDL (excluding MIL).

  Here, GDL 112 (including MIL) is described as a constituent member of fuel cell 10 other than MEA 110, but whether or not GDL is included in MEA 110 is not a problem and may be included in the constituent members of MEA 110. When the GDL is included in the MEA 110, the adhesive part 140 is formed for the purpose of simplifying the cell assembly with the CCM 110 and preventing the performance degradation by lightly adhering the GDL 112 to the separator 120 side during cell assembly. It will be a thing.

(5) Separator 120
The anode separator 120a and the cathode separator 120b are not particularly limited, such as those made of carbon such as carbon paper, carbon cloth, dense carbon graphite, and carbon plate, and those made of metal such as stainless steel. Can be used. In addition, the separators 120a and 120b have a function of separating air and fuel gas, and anode-side fuel gas (H ₂ ) processed into a desired shape in order to secure the flow paths thereof. It is desirable that a gas flow path (groove) 121a and a cathode-side air (Air) gas flow path 121b be formed, and a conventionally known technique can be appropriately used. The thicknesses and sizes of the separators 120a and 120b, the shapes of the flow channel grooves 121a and 121b, and the like are not particularly limited, and may be appropriately determined in consideration of output characteristics of the obtained fuel cell.

(6) Gasket 130, protective sheet layer 150
The anode-side and cathode-side gaskets 130a and 130b may be impermeable to gas, particularly oxygen or hydrogen gas, but in general, a single impermeable material such as an O-ring made of a gas-impermeable material. What is necessary is just to be comprised by the permeation | transmission part (refer FIG. 1). Further, for the purpose of bonding to the electrolyte membrane 100 and the edges of the anode and cathode catalyst layers 111a and 111b, a composite structure (anode) further provided with protective sheet layers 150a and 150b such as a gas seal tape with an adhesive. A laminated seal structure of the side gasket 130a + protective sheet layer 150a and a laminated seal structure of the cathode side sket 130b + protective sheet layer 150b) (see FIGS. 2 and 4). There are no particular limitations on the material that forms the impervious portion of the O-ring or gas seal tape as long as it is impervious to oxygen and hydrogen gas in a state where a predetermined pressure is applied after installation.

(I) Gasket 130
Examples of materials that are impermeable to oxygen and hydrogen gas constituting the anode-side and cathode-side gaskets 130a and 130b include rubber materials such as fluorine rubber, silicon rubber, ethylene propylene rubber (EPDM), and polyisobutylene rubber. , Fluoropolymer materials such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyhexafluoropropylene, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and thermoplastics such as polyolefin and polyester In addition to resins, those having stress resistance such as polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and polyimide (PI) can be mentioned.

  The thickness of the anode-side and cathode-side gaskets 130a, 130b is impermeable to oxygen and hydrogen gas in a state where a predetermined pressure is applied after installation according to the thickness of the GDL and the catalyst layer. What is necessary is just to determine suitably so that can be shown.

(Ii) Protective sheet layer 150
By providing the anode-side and cathode-side protective sheet layers 150a and 150b, the electrolyte membrane 100 is protected, which is excellent in that the load of the gaskets 130a and 130b can be prevented from being directly applied to the electrolyte membrane 100.

  As a material constituting the impervious portions of the anode side and cathode side protective sheet layers 150a and 150b, in addition to the fluorine-based polymer material and the thermoplastic resin similar to the gasket, those having stress resistance characteristics, etc. Can be used. For example, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyimide (PI), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF) and the like can be suitably used.

  In addition, the material constituting the bonded portion of the anode-side and cathode-side protective sheet layers 150a and 150b is not particularly limited as long as the electrolyte membrane 100, the anode and cathode catalyst layer 111, and the gasket 130 can be bonded closely. However, hot-melt adhesives such as polyolefin, polypropylene and thermoplastic elastomer, acrylic adhesives, olefin adhesives such as polyester and polyolefin can be used.

  The method for forming the anode side and cathode side protective sheet layers 150a and 150b is not particularly limited, and a known method can be used. For example, after applying an adhesive to be used as an adhesive portion of the protective sheet layer 150 on the electrolyte membrane 100 or on the electrolyte membrane 100 while covering the edge of the catalyst layer 111 so as to have a thickness of 5 to 30 μm. By applying the gas-impermeable material constituting the impermeable portion of the protective sheet layer 150 as described above so as to have a thickness of 10 to 200 μm, and heating this at 25 to 150 ° C. for 10 seconds to 10 minutes. A curing method can be used. Alternatively, after the gas impermeable material constituting the impermeable portion of the protective sheet layer 150 is formed into a sheet shape in advance, an adhesive used as an adhesive portion of the protective sheet layer 150 is applied to the impermeable film to protect it. After forming the sheet layer 150, the sheet layer 150 may be bonded to the electrolyte membrane 100 or to the electrolyte membrane 100 while covering the edge of the catalyst layer 111. Alternatively, a gas impermeable material constituting the impermeable portion of the protective sheet layer 150 is previously formed into a sheet shape, and then this impermeable film is bonded onto the adhesive layer used as the adhesive portion of the protective sheet layer 150. You may arrange | position on a film | membrane.

  The thicknesses of the anode-side and cathode-side protective sheet layers 150a and 150b are not particularly limited as long as sufficient adhesion between the electrolyte membrane 100 and the gasket 130 (further, GDL base material or MIL) can be achieved. Therefore, the thickness of the gasket, GDL, and catalyst layer may be determined as appropriate so as to be impervious to oxygen and hydrogen gas in a state where a predetermined pressure is applied after installation. For example, as shown in FIGS. 2 and 4, when the catalyst layer 111 is formed to have substantially the same thickness as the catalyst layer 111, the thickness of the catalyst layer described above may be adjusted. Specifically, the thickness is preferably 1 to 30 μm, more preferably 1 to 20 μm. In addition, although not shown in the figure, when the thickness is approximately the same as the total thickness of the catalyst layer + MIL layer, the total thickness of the catalyst layer + MIL layer described above may be adjusted. Specifically, the thickness is preferably 5 to 100 μm, more preferably 10 to 50 μm.

  About the said gasket 130 and the protective sheet layer 150, you may purchase and use a commercially available thing. The commercial items mentioned here include ordered items or custom-made items manufactured by the manufacturer according to the specifications (size, shape, material, characteristics, etc.) on the purchaser side.

  As shown in FIGS. 2 and 4, the installation range of the protective sheet layer 150 may be provided at the bonding portion between the membrane and the gasket. For example, as shown in FIG. 2, it may be formed to the inner side of the end face of the outer periphery of the GDL so that it can be bonded to the GDL. 2 and 4, it is desirable that the GDL outer peripheral end face and the gasket 130 be in contact with each other as shown in FIGS. 2 and 4, but a gap is formed between the GDL outer peripheral end face and the gasket. It may be. In such a case, the protective sheet layer 150 may be formed to the outer side (for example, the inner peripheral end surface of the gasket) than the GDL outer peripheral end surface. Desirably, the in-plane direction inner end portion of the protective sheet layer 150 is positioned inward beyond the in-plane direction inner end portion of the gasket 130, and a part of the protective sheet layer 150 overlaps a part of the GDL. It is desirable to be positioned as follows.

  The configuration of the cell unit of the fuel cell according to the present embodiment is not limited to the configurations shown in FIGS. 2 and 3 and any conventionally known technique may be used as appropriate. For example, regarding the sandwiching structure between the MEA and the separator, the sandwiching may be performed via an adhesive layer or sandwiched via a lip (in this case, a structure that is compressed and fixed by assembling a fuel cell stack). Also good. Further, the lip may be formed on the MEA side or may be formed on the separator side, and is not particularly limited.

  As the types of fuel cells that can use the cell unit of the fuel cell of the present invention, the polymer electrolyte type fuel cell has been described as an example in the above description. And a micro fuel cell. Among them, a polymer electrolyte fuel cell is preferable because it is small in size, and can achieve high density and high output. The fuel cell is useful as a stationary power source in addition to a power source for a moving body such as a vehicle in which a mounting space is limited. However, the fuel cell is particularly useful for an automobile application in which system start / stop and output fluctuation frequently occur. It can be particularly preferably used.

  The polymer electrolyte fuel cell is useful not only as a stationary power source but also as a power source for a moving body such as an automobile having a limited mounting space. In particular, moving bodies such as automobiles that are susceptible to corrosion of the carbon support due to the high output voltage required after a relatively long shutdown, and deterioration of the polymer electrolyte due to the high output voltage being taken out during operation. It is particularly preferred to be used as a power source.

  The polymer electrolyte fuel cell is useful not only as a stationary power source but also as a power source for a moving body such as an automobile having a limited mounting space. In particular, moving bodies such as automobiles that are susceptible to corrosion of the carbon support due to the high output voltage required after a relatively long shutdown, and deterioration of the polymer electrolyte due to the high output voltage being taken out during operation. It is particularly preferred to be used as a power source.

[II] Second Embodiment FIG. 4 is a cross-sectional view of the configuration of a fuel cell according to a second embodiment of the present invention. FIG. 5 shows that the positional relationship is clarified.

  Depending on the operating temperature of the fuel cell, it is suggested that elution of the adhesive used in the bonding portion 140 described in the first embodiment may occur. Therefore, in the unit fuel cell (fuel cell) according to the present embodiment, the separator and / or the gas diffusion layer has a function of preventing the adhesive from eluting and closing the separator flow path. By having the function, it is excellent in that it is possible to suppress the performance degradation due to clogging of the gas flow path because the adhesive is eluted and the gas flow path is blocked.

  In the unit fuel cell (fuel cell) 10 according to the present embodiment, as shown in FIGS. 4 and 5, the gas flow channel 121 a is assumed to have a function of preventing the adhesive from eluting and blocking the separator flow channel. , 121b is provided with anode-side and cathode-side guides 160a, 160b for preventing the adhesives 140a, 140b from being eluted. By providing the guides 160a and 160b, the adhesive of the bonding portions 140a and 140b is prevented from eluting and blocking the gas flow paths 121a and 121b, so that the performance deterioration due to the clogging of the flow paths 121a and 121b is suppressed. I can do it. That is, as shown in FIGS. 4 and 5, the unit fuel cell (fuel cell) 10 according to the second embodiment of the present invention has the basic configuration of the fuel cell shown in FIGS. Although it is the same as that of the structure of the fuel cell which concerns on embodiment, in this embodiment, the anode side and cathode side aiming at the elution prevention of the adhesive part 140a, 140b further before gas flow path 121a, 121b are further provided. Guides 160a and 160b are provided. Also in FIG. 5, since the basic configuration on the anode side and the cathode side is the same as in FIG. 3, the separator 120, the gas flow path (groove) 121, the gasket 130, and the adhesive are bonded without distinction between the anode side and the cathode side. Part 140 and guide 160 are shown. Hereinafter, the configuration requirements of the guide 160 will be described. The other constituent elements are the same as those described in the respective constituent elements of the fuel cell according to the first embodiment of the present invention described above, and thus the description thereof is omitted here.

(7) Guide 160
As a guide material that can be used for the guide 160, the same material as that of the separator 120 can be used. Specifically, it is not particularly limited, such as carbon paper, carbon cloth, dense carbon graphite, carbon plate, or a metal such as stainless steel, and conventionally known ones can be used. Further, the same member as the GDL 112 may be used for the guide material. Furthermore, the material is not limited to these as long as it effectively exhibits the function as the guide and does not affect the performance of the fuel cell, and various materials can be used.

  That is, even if it is the same member as the separator and GDL, by devising the shape (structure), hardness, etc., the adhesive is eluted and the adhesive flows into the gas flow path through the interface between the separator and the GDL. It is only necessary to prevent this. Therefore, for example, a part of the separator or the GDL may be uneven so that the adhesive does not flow through the gap at the interface. Therefore, the guide 160 portion (convex structure portion: weir structure) shown in FIGS. 4 and 5 may be a void structure portion (concave structure portion). Even when the void structure portion (concave structure portion: groove structure) is formed, the eluted adhesive flows into the portion and does not reach the gas flow path beyond that, so that the gas flow path can be prevented from being blocked. In addition, even if the void structure portion (concave structure portion: groove structure) is arranged in the same position and shape as the guide 160 shown in FIGS. 4 and 5, the original functions of the separator and the GDL are not impaired. The gas diffusion layer can sufficiently exhibit a function of suppressing the adhesive from eluting and blocking the separator flow path.

  The heights (or groove depths) H1 and H2 of the guide 160 (or gap structure portion) formed to prevent the adhesive from eluting and blocking the gas flow path 121 are all 0. .2 mm or less, desirably 0.1 mm or more and 0.2 mm or less. By having such a height (or depth), it is possible to prevent the eluted adhesive from moving through the gap between the separator and the GDL.

  Further, as shown in FIG. 4, the guide 160 portion is formed by integrally forming a guide portion having a height H1 on the separator 120 side and a guide having a height H2 on the GDL 112 side, so that the adhesive elutes and the gas is eluted. It is excellent in that the flow path 121 can be effectively prevented from being blocked and the assembly is facilitated.

  Further, as shown in FIG. 5, the installation location in the in-plane direction of the guide is arranged continuously between the adhesion location and the gas flow path so that the adhesive is not eluted and enters the gas flow path. Good. Therefore, it is desirable that both ends of the guide reach the gasket as shown in FIG. This is because if the guide is discontinuous and there is a gap portion, the adhesive eluted through the gap portion may flow into the gas flow path.

  In the fuel cell of the present invention having the above-described configuration, the cell performance can be improved as compared with a fuel cell assembled by performing a conventional hot press, as shown in Examples described later. In the conventional fuel cell, the water absorption of the film is lowered by hot pressing performed for the purpose of integrating (assembling) GDL and CCM, and a difference in resistance polarization occurs. However, in the fuel cell according to the present invention, since the separator and the GDL are bonded, the GDL integrated with the separator and the CCM can be assembled (integrated) without performing the hot press. It is considered that the water absorption can be prevented from being lowered and excellent battery performance can be exhibited without causing a resistance polarization difference. As described above, it can be said that the fuel cell of the present invention is characterized in that the GDL bonded to the separator and the CCM are assembled without performing hot pressing. Furthermore, it can be said that the fuel cell of the present invention has an adhesive portion where the separator and the GDL are bonded.

  Examples of the fuel cell include a polymer electrolyte fuel cell; a direct methanol fuel cell, and a micro fuel cell. Further, the fuel cell is useful as a stationary power source in addition to a power source for a moving body such as a vehicle in which a mounting space is limited, but particularly in an automobile application in which system start / stop and output fluctuation frequently occur. It can be used suitably. In particular, a polymer electrolyte fuel cell is useful as a power source for a mobile object such as an automobile having a limited mounting space in addition to a stationary power source because it is small in size and high in density and high in output.

  The fuel cell of the present invention will be specifically described below based on examples.

Example 1 and Comparative Example 1: Production of Fuel Cell (Test Sample) A sulfonated polyethersulfone (S-PES) electrolyte membrane, which is a hydrocarbon-based membrane, was used as a test sample. A catalyst layer sheet containing Nafion as an electrolyte was transferred to the S-PES electrolyte membrane by a transfer method to form a membrane-catalyst assembly (CCM).

  Here, for the production of the catalyst layer sheet, 5 g of platinum-supported carbon powder (TEC10E50E manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) in which platinum is supported on ketjen black at 50 wt% and 4.6 g of water are mixed and stirred and defoamed. Went. Next, 55 g of a 5 wt% polyelectrolyte (Nafion) dispersion (Dupont, DE-520) diluted with 1-propanol (NPA) is mixed, sufficiently stirred and degassed, and further using a homogenizer The catalyst layer ink was prepared by pulverizing and homogenizing at room temperature for 3 hours or more. The catalyst ink was cast on a transfer sheet, and the solvent was removed over 24 hours at 25 ° C. in an air atmosphere to prepare a catalyst layer (thickness 20 μm, area 5 cm × 5 cm) sheet.

  Then, the obtained CCM and GDL were hot-pressed and integrated (fuel cell) as a unit fuel cell (fuel cell) of Comparative Example 1, and the obtained CCM was obtained without performing hot pressing. A unit fuel cell (fuel cell) of Example 1 of the present invention was obtained by separately assembling and GDL (fuel cell). Here, as GDL, carbon paper (carbon paper TGP-H-060 manufactured by Toray Industries, Inc., having a thickness of 190 μm) punched into a 7 cm square was used. Moreover, the hot press conditions of the comparative example 1 were heating temperature 130 degreeC, press pressure 2Mpa, and pressure holding time 5min. A protective sheet made of polyethylene naphthalate (PEN) and a gasket made of silicon rubber were arranged on the outer periphery of the obtained electrolyte membrane of the integrated CCM and GDL, and were sandwiched from both sides by a separator. This was further sandwiched between two stainless steel end plates via a current collector plate and an insulating plate, and the end plates were fastened with a fastening rod to obtain a fuel cell for a test sample of Comparative Example 1.

  In Example 1, the GDL and the separator were bonded and assembled in advance as shown in FIGS. Specifically, an epoxy-based adhesive is applied to the outer edge portion from each gas flow path of the anode and cathode separator by spray coating method so as to be bonded to a plurality of surfaces (specifically, an adhesive spot shown in FIG. 3B), After bonding and fixing, the cell was assembled with the CCM. That is, both sides (both sides) of the CCM were sandwiched by GDL with a separator attached. This is sandwiched between two stainless steel end plates via the same current collector plate and insulating plate as in Comparative Example 1, and the end plates are fastened with a fastening rod, and the fuel cell for the test sample of Example 1 A cell.

  Here, dense carbon graphite was used for the separator. Using this separator, the outer dimensions are 2 mm in thickness, 130 mm in height, and 260 mm in width. On the surface facing the cathode or anode, the area of 20 cm × 9 cm in the central portion of the separator plate is 2.9 mm pitch and the width is about 2 mm. Gas flow paths were formed.

≪Battery characteristics evaluation test≫
The battery characteristics of the fuel cells obtained in Example 1 and Comparative Example 1 were as follows: the cell temperature was 70 ° C., H ₂ was used for the anode, and Air was used for the cathode, and the gas utilization was 66% for the anode and 40% for the cathode. . The humidification conditions were 60% anode humidity, 50% cathode humidity, and both the anode and cathode were tested under no pressure condition. The obtained result is shown in FIG.

The cell voltage and cell resistance were measured by changing the current density from 0 to 1.1 (A / cm ² ).

  The cell resistance was measured by using an AC resistance meter and fixing the frequency to 1 kHz.

≪Results and discussion by battery characteristics evaluation test≫
A fuel cell in Example 1 (a configuration example of a fuel cell according to the first embodiment of the present invention: see FIGS. 2 and 3B) and a fuel cell in a comparative example 1 (a configuration example of a conventional fuel cell: see FIG. 1) A characteristic diagram is shown in FIG. FIG. 6 is a graph of battery characteristics representing the relationship between the current density and the voltage of the fuel cell in Example 1 and Comparative Example 1. It can be seen that the performance of the fuel cell according to the example in the figure is improved as compared with the assembly of the comparative example hot-pressed.

  This is considered to be because the water absorption of the film is lowered by the hot pressing performed in the comparative example, and a difference occurs in the resistance polarization.

  That is, it can be seen from FIG. 6 that when hot pressing is performed and GDL and CCM are integrated, the battery performance is lowered as compared with the case where GDL and CCM are integrated. Further, although not shown in the figure, it can be seen that the performance matches when the resistance polarization is subtracted. From this, it can be inferred that performing hot pressing reduces the water absorption of the film, causing a decrease in performance. Thus, it can be seen that it is preferable to improve the performance by assembling cells without integrating GDL and CCM. However, if the GDL and the separator are assembled separately, the cell assembly becomes complicated. In this embodiment, as shown in FIGS. 2 to 5, GDL is lightly adhered to a portion where the flow path of the separator does not exist, and cell assembly is performed in that state, so that the cell assembly is not complicated and the battery performance is also improved. It was confirmed that an excellent effect of improvement could be expressed.

It is the cross-sectional schematic which represented typically the structure of the typical unit fuel cell (fuel cell) of the conventional fuel cell. It is sectional drawing which represented typically the structure of the typical unit fuel cell (fuel cell) of the fuel cell which concerns on 1st embodiment of this invention. FIG. 3 is a top view of the entire unit fuel cell (fuel cell) of FIG. 2 (expressed so that the positional relationship between the flow path, the gasket, and the adhesive portion is clear through the separator). FIG. 3A is a top schematic view schematically showing an example in which the separator (GDL) adhesion portion (adhesion portion) is formed by a plurality of point adhesions, and FIG. 3B shows the separator and GDL adhesion portion (adhesion portion). It is the upper surface schematic which represented typically the example formed by several surface bonding. It is sectional drawing which represented typically the structure of the typical unit fuel cell (fuel cell) of the fuel cell concerning 2nd embodiment of this invention. FIG. 5 is a top view of the entire unit fuel cell (fuel cell) of FIG. 4 (expressed so that the positional relationship between the flow path, the gasket, and the bonding portion is clear through the separator). FIG. 5A is a schematic top view schematically showing an example in which the separator (GDL) adhesion portion (adhesion portion) is formed by a plurality of point adhesions, and FIG. 5B shows the separator and GDL adhesion portion (adhesion portion). It is the upper surface schematic which represented typically the example formed by several surface bonding. 6 is a graph of battery characteristics showing the relationship between the current density of a fuel cell and its voltage in Example 1 and Comparative Example 1.

Explanation of symbols

    10 Fuel cell.

100 electrolyte membrane,
110 CCM (MEA),
111 catalyst layer,
111a anode catalyst layer,
111b cathode catalyst layer,
112 GDL,
112a Anode GDL,
112b cathode GDL,
120 separator,
120a anode separator,
120b cathode separator,
121 gas flow path (groove),
121a anode side H ₂ gas flow path (groove),
121b Cathode side Air gas flow path (groove),
130 gasket,
130a Anode side gasket,
130b cathode side gasket,
140 Adhesives,
140a anode adhesion part,
140b cathode adhesion part,
150 protective sheet layer,
150a anode side protective sheet layer,
150b cathode side protective sheet layer,
160 guides,
160a Anode side guide,
160b Cathode side guide H1 Height of the guide portion on the separator side,
H2 Height on the GDL side of the guide part.

Claims (8)

  A solid oxide fuel cell, wherein a separator and a gas diffusion layer are bonded and assembled with an adhesive, and an adhesion portion between the separator and the gas diffusion layer is located at an outer edge portion from a gas flow path of the separator.   2. The bonding portion between the separator and the gas diffusion layer is formed between the anode separator and the anode gas diffusion layer and between the cathode separator and the cathode gas diffusion layer, respectively. The solid oxide fuel cell as described.   3. The solid oxide fuel cell according to claim 1, wherein the bonding portion between the separator and the gas diffusion layer is a plurality of surface bonding or point bonding.   The solid oxide fuel cell according to any one of claims 1 to 3, wherein the adhesive applied to the adhesion portion is applied by a spray coating method.   The solid electrolyte fuel cell according to any one of claims 1 to 4, wherein the adhesive used for bonding the separator and the gas diffusion layer is an epoxy adhesive.   The solid oxide fuel cell according to any one of claims 1 to 5, wherein the separator and / or the gas diffusion layer has a function of suppressing the elution of the adhesive and blocking the separator flow path. .   As a function of suppressing blocking of the separator flow path, the eluted adhesive moves to the separator flow path at the interface between the separator and the gas diffusion layer and the gas flow path of the separator. The solid oxide fuel cell according to any one of claims 1 to 6, wherein a guide portion capable of preventing movement of the adhesive is provided at the interface portion serving as a path.   The method for producing a solid oxide fuel cell according to any one of claims 1 to 7, wherein the gas diffusion layer to which the separator is bonded and the CCM are assembled without performing hot pressing.

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