JP2006216402A - Manufacturing method of cell module for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of a cell module capable of efficiently forming a catalyst layer and a gas diffusion layer on the inner surface of a hollow electrolyte membrane and enhancing productivity. <P>SOLUTION: The manufacturing method of the cell module 101 for a fuel cell contains a process preparing an inner surface side electrode member 8 having the catalyst layer 2 on the outer circumferential surface of a rod-shaped porous body 3 having an expanding property from a steady state or a temporarily restricted state, a process inserting the inner surface side electrode member 8 into the hollow of the electrolyte membrane 1, and a process bonding the outer circumferential surface of the inner surface side electrode member 8 to the hollow inner surface of the electrolyte membrane 1 by expanding the inserted inner surface side electrode membrane. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a cell module having a hollow electrolyte membrane.

A fuel cell directly converts chemical energy into electrical energy by supplying fuel and an oxidant to two electrically connected electrodes and causing the fuel to be oxidized electrochemically. Unlike thermal power generation, it is not subject to the Carnot cycle, so it exhibits high energy conversion efficiency. A solid polymer electrolyte fuel cell is a fuel cell that uses a solid polymer electrolyte membrane as an electrolyte, and has advantages such as being easy to downsize and operating at a low temperature. It is attracting attention as a power source for mobile objects.
In the solid polymer electrolyte fuel cell, when hydrogen is used as the fuel, the reaction of the formula (1) proceeds at the anode.
H ₂ → 2H ⁺ + 2e ⁻ (1)
The electrons generated by the equation (1) reach the cathode after working with an external load via an external circuit. Then, the proton generated in the formula (1) moves by electroosmosis from the anode side to the cathode side in the solid polymer electrolyte membrane in a state of being hydrated with water.

Further, when oxygen is used as the oxidizing agent, the reaction of the formula (2) proceeds at the cathode.
2H ⁺ + (1/2) O ₂ + 2e ⁻ → H ₂ O (2)
The water produced at the cathode mainly passes through the gas diffusion layer and is discharged to the outside.
As described above, the fuel cell is a clean power generation device that has no emissions other than water.

Conventionally, as a solid polymer electrolyte fuel cell, a catalyst layer serving as an anode and a cathode is provided on one surface of a planar solid polymer electrolyte membrane, and the resulting planar membrane / electrode assembly is obtained. There has been developed a fuel cell stack obtained by laminating a plurality of flat single cells prepared by further providing gas diffusion layers on both sides and finally sandwiching them with a planar separator.
In order to improve the output density of the solid polymer electrolyte fuel cell, a proton conductive polymer membrane having a very thin film thickness is used as the solid polymer electrolyte membrane. This film thickness is already 100 μm or less, and even if a thinner electrolyte membrane is used to further improve the power density, the thickness of the single cell cannot be dramatically reduced from the present one. Similarly, the catalyst layer, the gas diffusion layer, the separator, and the like have been made thinner, but there is a limit to improving the output density per unit volume even by making all these members thinner. Therefore, it is expected that it will not be possible to meet the demand for miniaturization in the future.
In addition, a sheet-like carbon material having excellent corrosivity is usually used for the separator. This carbon material itself is also expensive. However, in order to distribute the fuel gas and the oxidant gas almost uniformly over the entire surface of the planar membrane / electrode assembly, a gas is usually provided on the surface of the separator. Since the groove to be the flow path is finely processed, the processing makes the separator very expensive, which increases the manufacturing cost of the fuel cell.
In addition to the above problems, for flat single cells, the periphery of single cells stacked in multiple layers should be reliably sealed so that fuel gas and oxidant gas do not leak from the gas flow path. However, there are many problems such as technical difficulties, and power generation efficiency may decrease due to deflection or deformation of the planar membrane / electrode assembly.

In recent years, a solid polymer electrolyte fuel cell has been developed in which a cell module having electrodes on the inner surface side and outer surface side of a hollow electrolyte membrane is used as a basic power generation unit. (For example, see Patent Documents 1 to 4).
Usually, a suitable number of hollow cell modules are aligned with a predetermined interval in parallel in the longitudinal direction so that the reaction gas can be uniformly and smoothly supplied to the outer surface of the cell module, and fixed together. By collecting the anode and cathode of each cell module, a cell module assembly is formed, and the cell module assembly is used alone, or two or more cell module assemblies are connected in series or in parallel as required. Connect to and incorporate into the fuel cell.
In a fuel cell having such a hollow cell module, there is no need to use a member corresponding to a separator used in a flat type. Since different types of gas are supplied to the inner surface and the outer surface for power generation, it is not necessary to form a gas flow path. Therefore, cost reduction is expected in the manufacture. Further, since the cell module has a three-dimensional shape, the specific surface area with respect to the volume can be increased as compared with the flat single cell, and the power generation output density per volume can be expected to be improved.

JP-A-9-223507 JP 2002-158015 A Japanese Patent Laid-Open No. 2002-260685 JP 2002-289220 A

A hollow cell module can be produced by applying a catalyst layer and, if necessary, a gas diffusion layer on the outer and inner surfaces of a hollow (usually elongated cylindrical) electrolyte membrane, applying a coating liquid, and a sheet. A method in which electrodes are formed by laminating by a method such as material pasting and transfer, and a current collector is disposed on the inner and outer electrodes, or a hollow gas diffusion layer that serves as an inner gas diffusion layer An inner surface side catalyst layer, an electrolyte membrane, an outer surface side catalyst layer, and an outer surface side gas diffusion layer are sequentially formed on the outer peripheral surface of the member for coating by a method such as application of a coating liquid, application of a sheet material, transfer, and the like. There is a method of arranging a current collector on the side and outer surface electrodes.
However, it is difficult to form the catalyst layer and the gas diffusion layer on the inner surface side of the hollow electrolyte membrane, and the work is very troublesome.

  In view of such circumstances, an object of the present invention is to provide a method of manufacturing a cell module that can efficiently form a catalyst layer and a gas diffusion layer on the inner surface side of a hollow electrolyte membrane and has high productivity. is there.

A manufacturing method of a cell module for a fuel cell having a hollow electrolyte membrane and a pair of electrodes provided on a hollow inner surface and an outer surface of the electrolyte membrane according to the present invention is stable or temporarily restrained. The catalyst layer is provided on the outer peripheral surface of the rod-like porous body having expandability from the state of expansion, and in the state before expansion, the outer diameter including the catalyst layer has a size that allows insertion into the hollow of the electrolyte membrane A step of preparing an inner surface side electrode member having an easy axial rigidity and having an outer diameter including the catalyst layer that cannot be inserted into the hollow of the electrolyte membrane in the expanded state; A step of inserting the inner surface side electrode member into the hollow of the electrolyte membrane, and expanding the inserted inner surface side electrode member so that the outer peripheral surface of the inner surface side electrode member is hollow in the electrolyte membrane. A step of closely contacting the inner surface, and That.
According to the above invention, a catalyst module and a diffusion layer to be an electrode can be easily arranged in the hollow electrolyte membrane, and a cell module for a fuel cell having good adhesion at the interface between the electrolyte layer and the catalyst layer is produced. Can do.

As one embodiment of the method for producing a cell module for a fuel cell according to the present invention, a catalyst layer is provided on the outer peripheral surface of a rod-shaped porous body having a shape and dimension restoration property against compression, and the catalyst layer A step of preparing an inner surface-side electrode member whose outer diameter includes a size that cannot be inserted into the hollow of the electrolyte membrane, and the inner surface-side electrode member is impregnated with a liquid that can be solidified, and The outer diameter of the electrolyte membrane is compressed into a size that can be inserted into the hollow of the electrolyte membrane, and the inner electrode member is compressed by solidifying the liquid in the inner electrode member. The inner surface side electrode member in a solidified state is inserted into the hollow of the electrolyte membrane, and the solidified liquid in the inserted inner surface side electrode member is melted and compressed. Of the inner surface side electrode member A step of adhering the peripheral surface to the hollow inner surface of the electrolyte membrane, and a method having.
According to the above embodiment, by utilizing the liquid impregnation action and the solidification action, the inner surface side electrode member is temporarily restrained in the compressed state, and after being inserted into the hollow electrolyte membrane, it is released from the restrained state and expanded. Thus, it can be adhered and fixed to the hollow inner surface of the electrolyte membrane.

In the said embodiment, it is preferable to further have the process of removing the liquid which arose by melting the said solidified liquid from the hollow inside of an electrolyte membrane.
According to the embodiment, it is possible to prevent the cell module from being deteriorated due to the liquid remaining in the cell module.

In the said embodiment, it is preferable to make the said inner surface side electrode member into the state compressed to the diameter reduction direction.
By compressing the inner surface side electrode member in the diameter reducing direction, the catalyst layer can uniformly apply the diameter increasing direction pressure to the electrolyte membrane after melting.

  In the above embodiment, in the step of impregnating and compressing, outer diameter compression is performed after liquid impregnation, liquid impregnation is performed after outer diameter compression, or liquid impregnation and outer diameter compression are performed. It may be performed at the same time or by any procedure.

In the said embodiment, it is preferable to use water as said liquid.
Water is suitable because it is inexpensive, has a suitable melting point and freezing point, and is a substance that usually exists or is generated in the cell module, and therefore does not cause deterioration of the cell module.

  In the said embodiment, the rod-shaped porous body which has the restoring property of a shape and a dimension with respect to compression can be selected and used from what consists of a porous material which has carbon fiber or a metal fiber as a main component.

As an embodiment of the method for manufacturing a cell module for a fuel cell according to the present invention, the inner electrode member has a rod-shaped porous body having a porosity of 70 to 90%, and the outer diameter including the catalyst layer is the electrolyte membrane. It is preferable to use a member for an inner surface side electrode that is 1.1 to 1.2 times the inner diameter of the inner diameter, and to set the compression rate in the diameter reducing direction to 0.7 or less.
According to the above embodiment, an appropriate amount of liquid impregnation is ensured during the compression step, so that the compression state can be reliably fixed during solidification. In addition, after thawing, the interface pressure between the catalyst layer and the inner surface of the electrolyte membrane is optimized, so that the adhesion is good, and the porous structure is not damaged even after insertion, so gas is introduced to the hollow inner surface side of the cell module. Can be fully supplied.

  According to the method for manufacturing a cell module for a fuel cell of the present invention, the catalyst layer and the gas diffusion layer can be efficiently formed on the inner surface side of the hollow electrolyte membrane, and the manufacture of the cell module with high productivity is realized. Can do.

  The method for producing a fuel cell module according to the present invention is a method for producing a fuel cell module having a hollow electrolyte membrane and a pair of electrodes provided on the hollow inner surface and outer surface of the electrolyte membrane, A catalyst layer is provided on the outer peripheral surface of the rod-like porous body having expandability from the state or from a temporarily constrained state, and the outer diameter including the catalyst layer is in the hollow of the electrolyte membrane before the expansion. The inner surface has a size that can be inserted and an axial rigidity that facilitates insertion, and an outer diameter that includes the catalyst layer in a state after expansion that cannot be inserted into the hollow of the electrolyte membrane. A step of preparing a member for a side electrode, a step of inserting the member for an inner surface side electrode into the hollow of the electrolyte membrane, and expanding the inserted member for an inner surface side electrode, The outer peripheral surface of the electrolyte membrane is sealed to the hollow inner surface of the electrolyte membrane. And having a step of a.

  The rod-shaped porous body is a material that can be inflated and inserted into the hollow inner surface of the electrolyte membrane and brought into close contact with the hollow inner surface. Swellability from the stable state means that the volume or dimension is not essentially changed in the steady state, but irreversibly increases the volume or dimension by applying some action. Examples thereof include materials having thermal or chemical foamability (for example, foamable resins). Further, the expansibility from a temporarily constrained state means that the volume or dimension is reversibly increased by applying some action, and the material having such a property is rubber-like or spring-like. The material (for example, rubber | gum, a fiber, a nonwoven fabric) which has the elasticity or restoring force of these.

A rod-shaped porous body having such expansibility is used as a support for the inner surface side catalyst layer to prepare an inner surface side electrode member. And after inserting this inner surface side electrode member in the hollow of an electrolyte membrane in the state before expansion | swelling, the inner surface side catalyst layer closely_contact | adhered to the inner surface of an electrolyte membrane can be formed.
According to this method, the catalyst layer and the diffusion layer to be electrodes can be easily disposed in the hollow electrolyte membrane, and the adhesion at the interface between the hollow electrolyte membrane and the inner surface side catalyst layer is good. A cell module can be created.

  The rod-shaped porous body is rigid so that it can be easily inserted into the hollow by aiming at the opening end of the electrolyte membrane when inserted into the hollow of the electrolyte membrane, in other words, the self-supporting or shape of the material itself It is necessary to have holding ability. More specifically, when the rod-like porous body is lifted by grasping one end of the rod-like porous body under conditions such as the temperature at which insertion is performed, the shaft of the rod-like porous body is not substantially bent, and the electrolyte membrane It is preferable that the deflection (displacement in the lateral direction with respect to the axial direction) due to resistance when inserted into the hollow is 1% or less with respect to the total length of the rod-shaped porous body.

The rod-like porous body functions as a gas diffusion layer on the inner surface side after being expanded in the hollow of the electrolyte membrane. Further, since the hollow interior of the electrolyte membrane is normally filled with the expanded rod-shaped porous body, the portion of the rod-shaped porous body also needs to function as a hollow internal gas flow path. Therefore, the rod-shaped porous body needs to be a porous material having gas flowability that can function as a gas diffusion layer and a hollow gas passage.
Furthermore, the rod-shaped porous body itself can also serve as the inner surface side current collector. In that case, it is necessary that the rod-shaped porous body has conductivity sufficient to exhibit a current collecting function.

  As one embodiment of the production method of the present invention, a catalyst layer is provided on the outer peripheral surface of a rod-shaped porous body having resilience in shape and size against compression, and the outer diameter including the catalyst layer is the electrolyte. A step of preparing an inner surface side electrode member having a size that cannot be inserted into the hollow of the membrane; and the inner surface side electrode member is impregnated with a liquid capable of coagulation, and the outer diameter thereof is the electrolyte membrane. A step of compressing the inner surface side electrode member into a size that can be inserted into the hollow, solidifying the liquid in the inner surface side electrode member, and fixing the inner surface side electrode member to a compressed dimension; The inner surface side electrode member in a state of being inserted into the hollow of the electrolyte membrane, and the solidified liquid in the inserted inner surface side electrode member is melted and restored from the compressed state, the inner surface side The outer peripheral surface of the electrode member is the hollow inner surface of the electrolyte membrane. A step of adhering, and a method having.

  According to the method of this embodiment, by utilizing the liquid impregnation action and the coagulation action, the inner surface side electrode member is temporarily restrained in a compressed state, and is released from the restrained state after being inserted into the hollow electrolyte membrane. Then, it can be inflated and adhered and fixed to the hollow inner surface of the electrolyte membrane.

Hereinafter, the preferred embodiment will be described in detail.
First, the form of the cell module for fuel cells manufactured by the embodiment will be briefly described. In the following embodiment, a cell module assembly using a perfluorocarbon sulfonic acid membrane, which is one of solid polymer electrolyte membranes, which is a kind of proton conducting membrane, hydrogen gas as fuel, and air (oxygen) as an oxidant. Although the description will focus on the body, the present invention is not limited to such a configuration example.

The cell module according to the present invention has a hollow electrolyte membrane and a pair of electrodes provided on the hollow inner surface and outer surface of the electrolyte membrane. The hollow electrolyte membrane means an electrolyte membrane having a hollow shape in the axial direction.
FIG. 1 is a perspective view of a configuration example of a cell module (101) for a fuel cell according to the present invention, and FIG. 2 is a partially enlarged view showing an upper end portion (101a) and a lower end portion (101b) of the same cell module. It is a perspective view. Normally, the tubular cell module has an elongated cylindrical shape as shown in FIG. 1, but may have another shape as long as it has a structure having a reaction gas flow channel in the hollow.

1 and 2, a cell module 1 includes a tubular solid polymer electrolyte membrane (perfluorocarbon sulfonic acid resin membrane) 1 and an anode catalyst layer (inner surface side catalyst layer) provided on the inner surface side of the solid polymer electrolyte membrane 1. 2) A rod-like porous body portion (inner surface side gas diffusion layer) 3 provided so as to fill a hollow portion on the inner surface side of the anode catalyst layer 3; a cathode catalyst layer provided on the outer surface side of the solid polymer electrolyte membrane 1) (Outer surface side catalyst layer) 4 and a cathode side gas diffusion layer (outer surface side gas diffusion layer) 5 provided on the outer surface side of the cathode catalyst layer.
In the above configuration, the anode catalyst layer 2 and the rod-shaped porous body 3 constitute an anode electrode (in this example, a fuel electrode), and the cathode catalyst layer 4 and the cathode-side gas diffusion layer 5 serve as a cathode electrode (in this example, an air electrode). Constitute.

  Further, on the inner surface side of the tube-shaped solid polymer electrolyte membrane, a straight wire penetrates the rod-shaped porous body portion 3 in the axial direction of the tube as an anode current collector (inner surface side current collector) 6, and the cell module It arrange | positions so that it may protrude from one edge part. On the other hand, on the outer surface side of the solid polymer electrolyte membrane, a spring-like wire is in contact with the surface of the cathode-side gas diffusion layer as a cathode current collector (outer surface-side current collector) 7 and the other end of the cell module It is arrange | positioned so that it may protrude from.

  The anode catalyst layer 2, the rod-shaped porous body portion 3, and the anode current collector 6 of the cell module 101 previously form the anode catalyst layer 2 on the outer peripheral surface of the rod-shaped porous body portion 3, and the inside (usually the central axis or The inner electrode member for which the anode current collector 6 has been penetrated in the axial direction in the vicinity thereof is compressed, inserted into the hollow of the electrolyte membrane, and then restored from the compressed state to be fixed in the hollow. is there.

The cell module 101 has the tube-shaped solid polymer electrolyte membrane 1, but the hollow electrolyte membrane in the present invention is not limited to the tube shape, has a hollow portion, and fuel or an oxidant flows into the hollow portion. By doing so, it is only necessary that the reaction component necessary for the electrochemical reaction can be supplied to the electrode provided in the hollow interior.
As a material for the hollow electrolyte membrane, materials such as perfluorocarbon sulfonic acid and those used for an electrolyte membrane of a polymer electrolyte fuel cell can be used.

Since the fuel cell of the present invention has a cell module having a hollow shape, the electrode area per unit volume can be increased as compared with a fuel cell having a flat cell. Even when an electrolyte membrane that does not have proton conductivity as high as that of a fluorocarbon sulfonic acid membrane is used, a fuel cell having a high output density per unit volume can be obtained. For example, at least a sulfonic acid group, a phosphonic acid group, and a phosphoric acid group having a skeleton of a hydrocarbon such as polyolefin such as a fluorine-based ion exchange resin other than perfluorocarbon sulfonic acid, a polystyrene-based cation exchange membrane having a sulfonic acid group A base having a strong acid doped on a basic polymer such as polybenzimidazole, polypyrimidine, polybenzoxazole, etc., which has one kind of proton exchange groups such as JP-A-11-503262 And a polymer electrolyte such as a solid polymer electrolyte composed of a composite of a conductive polymer and a strong acid.
A solid polymer electrolyte membrane using such an electrolyte should be reinforced with a perfluorocarbon polymer in the form of a fibril, a fabric, a non-fabric, or a porous sheet, or the membrane surface can be coated with an inorganic oxide or metal. It can also be reinforced.

Further, the electrolyte membrane used in the fuel cell of the present invention is not particularly limited, and other ion conductivity such as hydroxide ion and oxide ion (O ²⁻ ) may be used even if it is proton conductive. It may be. The proton conductive electrolyte membrane is not limited to the solid polymer electrolyte membrane as described above, but a porous electrolyte plate impregnated with an aqueous phosphoric acid solution, a proton conductor made of porous glass, or a hydrogel Phosphated phosphate glass, organic-inorganic hybrid proton conductive membrane having proton conductive functional groups introduced into the surface and pores of nanoporous glass, inorganic metal fiber reinforced electrolyte polymer, etc. can be used. . Examples of other ion-conducting electrolytes such as hydroxide ions and oxide ions (O ²⁻ ) include those containing ceramics.

  The inner diameter, outer diameter, length and the like of the hollow electrolyte membrane 1 are not particularly limited, but the outer diameter of the electrolyte membrane is preferably 0.01 to 10 mm, preferably 0.1 to 1 mm. Is more preferable, and it is especially preferable that it is 0.1-0.5 mm. The electrolyte membrane having an outer diameter of less than 0.01 mm is currently difficult to manufacture due to technical problems, while the outer diameter of the electrolyte membrane exceeding 10 mm does not increase the surface area relative to the occupied volume. There is a possibility that an output per unit volume of the obtained cell module cannot be sufficiently obtained.

  In this embodiment, the perfluorocarbon sulfonic acid membrane used as the hollow solid polymer electrolyte membrane is preferably thin from the viewpoint of improving proton conductivity, but if it is too thin, the function of isolating gas is reduced, The permeation amount of aprotic hydrogen increases. However, in comparison with a conventional fuel cell in which flat cells for fuel cells are stacked, a fuel cell manufactured by collecting a large number of hollow cell modules can take a large electrode area. Even when is used, sufficient output can be obtained. From this viewpoint, the thickness of the perfluorocarbon sulfonic acid film is 10 to 100 μm, more preferably 50 to 60 μm, and still more preferably 50 to 55 μm.

  Moreover, from the preferable range of said outer diameter and film thickness, the preferable range of an internal diameter is 0.01-10 mm, More preferably, it is 0.1-1 mm, More preferably, it is 0.1-0.5 mm. is there.

The catalyst layers 2 and 4 provided on the inner and outer surfaces of the electrolyte membrane 1 can be formed using an electrode material such as that used in a polymer electrolyte fuel cell. Usually, an electrode configured by laminating a catalyst layer and a gas diffusion layer in order from the electrolyte membrane side is used.
The catalyst layer includes catalyst particles, and may include a proton conductive material for increasing the utilization efficiency of the catalyst particles. As the catalyst particles, catalyst particles in which a catalyst component is supported on a conductive material such as a carbon material such as carbonaceous particles or carbonaceous fibers are preferably used. As the proton conductive substance, those used as the material for the electrolyte membrane can be used. A fuel cell having a hollow cell module can take a larger electrode area per unit volume than a fuel cell having a flat cell, so even if a catalyst component that is not as catalytic as platinum is used, the unit volume A fuel cell having a high output density can be obtained.
The catalyst component is not particularly limited as long as it has a catalytic action on the hydrogen oxidation reaction at the anode and the oxygen reduction reaction at the cathode. For example, platinum, ruthenium, iridium, rhodium, palladium, osnium, tungsten, It can be selected from metals such as lead, iron, chromium, cobalt, nickel, manganese, vanadium, molybdenum, gallium, aluminum, or alloys thereof. Pt and an alloy made of Pt and another metal such as Ru are preferable.

In a conventional hollow cell module, an inner surface side catalyst layer is provided on the hollow inner surface of the electrolyte membrane, and if necessary, an inner surface side gas diffusion layer is further provided. The hollow part is left as it is, and this hollow part functions as a hollow inner gas flow path.
On the other hand, the rod-like porous body portion 3 of the cell module 101 has a compressibility that can be reduced to a size that can be inserted into the hollow of the electrolyte membrane, and a material that can be expanded to a size that can be brought into close contact with the hollow inner surface after insertion. The hollow portion of the electrolyte membrane 1 is filled with the rod-shaped porous body portion 3. Therefore, the rod-shaped porous body portion 3 functions as a gas diffusion layer of the anode catalyst layer 2 and also functions as a hollow gas channel.

Therefore, as the material of the rod-shaped porous body portion 3, a porous material having compressibility / restorability that can be inserted into the hollow of the electrolyte membrane, and gas flowability that can function as a gas diffusion layer and a gas flow channel in the hollow after insertion. Is used.
Such a porous material may be selected from those conventionally used as gas diffusion layers for flat plate or hollow cells. Suitable materials include, for example, porous materials mainly composed of carbon fibers or metal fibers (Pt, Au, Ti, etc.) (typically carbon cloth, carbon paper, carbon porous materials, etc.) And a mixture of knitted or knitted fibers mixed with two or more species) or sponge metal.

However, the porous material is not required to be completely recoverable, and any material can be used as long as the anode catalyst layer 2 can be brought into close contact with the hollow inner surface of the electrolyte membrane when the compressed state is released.
In addition, if the shape can be restored, a rod-shaped porous body that is hollow in the axial direction may be used instead of the rod-shaped porous body. In that case, it is only necessary to have gas permeability that can function as a gas diffusion layer, and gas flowability that can function as a hollow inner gas flow path is not required.
Further, the inner current collector (anode current collector 6) of the cell module 101 may be omitted, and the rod-shaped porous body portion 3 may function as the inner current collector. In that case, it is preferable to select a porous material having a relatively high conductivity in order to enhance the current collecting action.

  As the cathode side gas diffusion layer 5 provided on the outer surface of the cathode catalyst layer 4, a porous conductive material mainly composed of a carbon material such as carbonaceous particles and / or carbonaceous fibers can be used. The sizes of the carbonaceous particles and the carbonaceous fibers may be appropriately selected in consideration of the dispersibility in the solution when the gas diffusion layer is produced, the drainage property of the obtained gas diffusion layer, and the like. The gas diffusion layer is, for example, polytetrafluoroethylene, polyvinylidene fluoride (PVDF), polytetrafluoroethylene, perfluorocarbon alkoxyalkane, ethylene-tetrafluoroethylene polymer, or these from the point of improving the drainage of moisture such as generated water It is preferable to perform water-repellent processing by impregnating a mixture of the above or the like or forming a water-repellent layer using these substances.

The current collector is a conductor for taking out electric charges generated at the electrodes (anode and cathode) to an external circuit. In the present embodiment, a straight wire is disposed in the rod-shaped porous body 3 as the anode side (inner surface side) current collector 6, and a spring-like wire is used as the cathode side gas diffusion layer as the cathode side (outer surface side) current collector 7. They are placed in contact.
Examples of the metal that can be used as the current collector include at least one metal selected from Al, Cu, Fe, Ni, Cr, Ta, Ti, Zr, Sm, In, and the like, or those such as stainless steel. Alloys are preferred. Further, the surface thereof may be coated with Au, Pt, conductive resin or the like. Of these, stainless steel and titanium are preferred because of their excellent corrosion resistance.

  In this embodiment, the straight wire and the spring wire are used as described above, but the shape is not limited to these shapes, and the shape is arbitrary as long as it is made of an electrically conductive material. As other examples, for example, those made of a sheet material such as a metal foil, a metal sheet, or a carbon sheet can be applied. These current collectors are fixed on the electrodes with a conductive adhesive such as a carbon-based adhesive or an Ag paste as necessary.

The cell module of the present invention is not limited to the configuration exemplified above. For example, a layer other than the catalyst layer and the gas diffusion layer may be provided for the purpose of enhancing the function of the cell module.
In using the cell module of the present invention, as shown in FIGS. 1 and 2, the inner electrode is made into an anode by supplying a fuel such as hydrogen to the inner surface electrode and an oxidizing agent such as oxygen and air to the outer surface electrode. The outer electrode may be used as the cathode or vice versa.

FIG. 3 is a conceptual diagram showing the work procedure of the above embodiment including the compression / insertion / restoration steps of the inner surface side electrode member. FIG. 3 shows a cross section in which each member is cut in a direction parallel to the axis of the cell module.
In the procedure shown in FIG. 3, first, a straight wire is prepared as the anode current collector 6 (FIG. 3 a), and a porous material layer is formed around the wire, thereby producing the rod-shaped porous body portion 3 (FIG. 3). 3b). The layer of the porous material can be formed by applying a paste containing carbon particles on the surface of the linear wire, or forming a paper cloth with conductivity. In addition, when using the rod-shaped porous-body part 3 itself as an inner surface side collector, the rod-shaped porous-body part 3 which does not contain a linear wire can be shape | molded and used.

  Next, a catalyst particle and, if necessary, a solution containing a proton conductive material is applied to the outer periphery of the rod-shaped porous body 3 and dried to form the anode catalyst layer 2 to form an inner surface side electrode member 8 (FIG. 3c). ).

The inner surface side electrode member 8 has an outer diameter in an uncompressed state (after restoration) including the catalyst layer so that it cannot be inserted into the hollow of the hollow electrolyte membrane (usually, the inner surface side electrode member 8 The outer diameter after restoration must be equal to or greater than the hollow inner diameter of the electrolyte membrane. This is because when the cell module is completed, the outer peripheral surface of the inner surface side electrode member is brought into close contact with the hollow inner surface of the electrolyte membrane.
When both the electrolyte membrane and the rod-like porous body are in the shape of a perfect circle as in this embodiment, the outer diameter of the inner electrode member 8 obtained by applying the catalyst layer, including the catalyst layer, is The inner diameter of the hollow electrolyte membrane is preferably equal to or greater than that.

Next, the inner surface side electrode member 8 is impregnated with a liquid that can be solidified (not shown).
In the present invention, the liquid can be solidified by holding it at a temperature below the freezing point of the liquid, and the solidified liquid can be melted by holding it at a temperature above the melting point of the liquid.

It is desirable that the liquid used in the present invention does not deteriorate the material and performance of the cell module when it remains in the finished fuel cell. As a specific material, water is preferably used as the liquid. .
Since cell freezing (coagulation) and thawing (thawing) of frozen water are easy and water is a substance that normally exists or is generated in the cell module, the cell module may be deteriorated. Even if water generated in the manufacturing process remains, the power generation characteristics of the fuel cell are not significantly affected.
Hereinafter, in this embodiment, it demonstrates as what uses water as a liquid.

Next, pressure is applied to the cylindrical side surface of the inner surface-side electrode member 9 impregnated with water by a compression means 9 such as a press machine, and the outer diameter d1 is compressed in the hollow of the electrolyte membrane by compressing in the direction of diameter reduction. The size can be inserted (outer diameter d2) (FIGS. 3C and 3D).
When both the electrolyte membrane and the inner surface side electrode member are in the shape of a perfect circle as in this embodiment, the outer diameter of the inner surface side electrode member 9 is smaller than the inner diameter of the electrolyte membrane. Compress the porous body.

The porosity of the rod-shaped porous body, the outer diameter including the catalyst layer, and the compressibility in the direction of diameter reduction depend on the material used, but the porosity is 70 to 90%, and the outer diameter including the catalyst layer is the above-mentioned It is 1.1 to 1.2 times the inner diameter of the electrolyte membrane, and the compression ratio in the direction of diameter reduction of the inner surface side electrode member is preferably 0.7 or less.
According to the above conditions, an appropriate amount of liquid impregnation is ensured during the compression step, so that the compressed state can be reliably fixed during solidification. In addition, after thawing, the interface pressure between the catalyst layer and the inner surface of the electrolyte membrane is optimized, so that the adhesion is good, and the porous structure is not damaged even after insertion, so gas is introduced to the hollow inner surface side of the cell module. Can be fully supplied.

  In the above procedure, the outer diameter is compressed after the liquid is impregnated, but the inner surface side electrode member 8 is impregnated with a liquid that can be solidified, and the outer diameter is in the hollow of the electrolyte membrane. What is necessary is just to be able to be in a state compressed into an insertable size, and the liquid impregnation may be performed after the outer diameter is compressed, or the liquid impregnation and the outer diameter are compressed at the same time. You may go on.

Next, the impregnated water is frozen while pressure is applied to the inner surface side electrode member 8, and the inner surface side electrode member is fixed to a compressed size (not shown).
Thus, the dimension of the inner surface side electrode member in the compressed state can be maintained by solidifying the liquid impregnated in the inner surface side electrode member 8 in the compressed state.

Next, the inner surface side electrode member 8 in a solidified state is inserted into the hollow of the electrolyte membrane 1 and disposed at a desired position (FIG. 2E). At this time, the inner surface side current collector 5 is projected from the tip of the electrolyte membrane.
The inner surface side electrode member 8 obtained by freezing water in the coagulation step has such a rigidity that it can be easily inserted without being bent when inserted into the hollow of the electrolyte membrane 1.

Next, the frozen water in the inserted inner surface side electrode member 8 is thawed and restored from the compressed state, and the outer peripheral surface of the inner surface side electrode member 8 is brought into close contact with the hollow inner surface of the electrolyte membrane 1. (FIG. 2 (f)).
By thawing water, the retained inner electrode member size is restored. Since the outer diameter of the inner surface side electrode member before compression is larger than the inner diameter of the hollow electrolyte membrane, the inner surface side electrode member and the inner surface of the hollow electrolyte membrane are in the process of restoring the size. Stress is generated and fixed.
The melted liquid flows out from the inner surface of the cell module and is removed. However, if necessary, a removing means such as washing with another solvent or evaporation by heating may be added. In the case of impregnating with water, as described above, there is no possibility that the residue will deteriorate the cell module, so that it is sufficient to simply flow out of the cell module after melting.

  When both the electrolyte membrane and the inner surface side electrode member are in the shape of a perfect circle as in the present embodiment, when the frozen liquid is melted without entering the hollow of the electrolyte membrane, the inner surface side electrode member It is preferable that the shape and dimensions of the porous body can be restored so that the outer diameter of the porous body is larger than the inner diameter of the electrolyte membrane.

Furthermore, since it has an appropriate resilience against compression, it is possible to generate a reaction force at the interface between the catalyst layer and the electrolyte layer.
Although it is not necessary to restore the size of the inner surface side electrode member after restoration to 100% of the volume before compression, it is preferable that the reaction force after restoration can be secured to about 1 MPa to 5 MPa.

Through the above steps, the inner surface side electrode is arranged inside the hollow of the electrolyte membrane.
According to the above manufacturing method, the catalyst module and the diffusion layer serving as electrodes can be easily arranged in the hollow electrolyte membrane, and the cell module for a fuel cell having good adhesion at the interface between the electrolyte layer and the catalyst layer is obtained. Can be created.
If possible, two or more of the above steps may be performed simultaneously.

It is a perspective view of one structural example of the cell module for fuel cells based on this invention. It is the fragmentary perspective view which expanded the both ends of the cell module of FIG. It is the conceptual diagram which showed the procedure which arrange | positions the inner surface side electrode member based on one Embodiment of this invention in the hollow inside of a hollow electrolyte membrane.

Explanation of symbols

101 Cell module 1 Hollow electrolyte membrane 2 Anode catalyst layer 3 Rod-shaped porous body 4 Cathode catalyst layer 5 Cathode side diffusion layer 6 Anode current collector (straight wire)
7 Cathode current collector (spring wire)
8 Inner surface side electrode member 9 Compression means

Claims (8)

A method for producing a cell module for a fuel cell comprising a hollow electrolyte membrane and a pair of electrodes provided on the hollow inner surface and outer surface of the electrolyte membrane,
A catalyst layer is provided on the outer peripheral surface of the rod-like porous body having expandability from a stable state or a temporarily constrained state, and the outer diameter including the catalyst layer is in the hollow space of the electrolyte membrane in a state before expansion. The outer diameter including the catalyst layer has a size incapable of being inserted into the hollow of the electrolyte membrane. Preparing an inner surface side electrode member;
Inserting the inner surface side electrode member into the hollow of the electrolyte membrane;
Expanding the inserted inner surface side electrode member to bring the outer peripheral surface of the inner surface side electrode member into close contact with the hollow inner surface of the electrolyte membrane. A method for producing a cell module for a fuel cell comprising a hollow electrolyte membrane and a pair of electrodes provided on the hollow inner surface and outer surface of the electrolyte membrane,
A catalyst layer is provided on the outer peripheral surface of the rod-shaped porous body having shape and dimension resilience to compression, and the outer diameter including the catalyst layer is a size that cannot be inserted into the hollow of the electrolyte membrane. Preparing an electrode member;
A step of impregnating the inner electrode member with a liquid that can be solidified, and the outer diameter thereof being compressed to a size that can be inserted into the hollow of the electrolyte membrane;
Solidifying the liquid in the inner surface side electrode member and fixing the inner surface side electrode member to a compressed size;
Inserting the solidified electrode member on the inner surface side into the hollow of the electrolyte membrane;
Melting the solidified liquid in the inserted inner surface side electrode member to restore it from the compressed state, and bringing the outer peripheral surface of the inner surface side electrode member into close contact with the hollow inner surface of the electrolyte membrane. Manufacturing method of battery cell module.   The method for producing a cell module for a fuel cell according to claim 2, further comprising a step of removing the liquid produced by melting the solidified liquid from the hollow space of the electrolyte membrane.   The manufacturing method of the cell module for fuel cells of Claim 2 or 3 which makes the said inner surface side electrode member the state compressed in the diameter reduction direction.   3. In the impregnation and compression step, outer diameter compression is performed after liquid impregnation, liquid impregnation is performed after outer diameter compression, or liquid impregnation and outer diameter compression are performed simultaneously. 5. A method for producing a cell module for a fuel cell according to any one of 4 above.   The method for producing a cell module for a fuel cell according to claim 2, wherein water is used as the liquid.   The method for producing a fuel cell cell module according to any one of claims 2 to 6, wherein the rod-shaped porous body is made of a porous material mainly composed of carbon fiber or metal fiber. The inner surface side electrode member has a rod-shaped porous body with a porosity of 70 to 90%, and the outer diameter including the catalyst layer is 1.1 to 1.2 times the inner diameter of the electrolyte membrane. Using the members,
The manufacturing method of the cell module for fuel cells in any one of Claims 2 thru | or 7 which makes the compression rate of a diameter reduction direction 0.7 or less.

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