JP2008027672A - Conductive porous body and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive porous body and its manufacturing method capable of controlling pore diameters and curtailing manufacturing cost by simplifying manufacturing processes. <P>SOLUTION: The conductive porous body is provided with at least a conductive porous part structured by laminating a first fiber group formed by planarly arraying a plurality of first conductive fibers, and a second fiber group formed by arraying a plurality of second conductive fibers so as to cross the plurality of first conductive fibers, and a frame body fitted at an outer edge of the conductive porous part for fixing the conductive porous part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a conductive porous body and a method for producing the same, and specifically relates to a conductive porous body that can be used as a filter, a diffusion layer for a fuel cell, and the like, and a method for producing the same.

  A fuel cell has a membrane electrode assembly (hereinafter referred to as “MEA (Membrane Electrode)” comprising an electrolyte layer (hereinafter referred to as “electrolyte membrane”) and electrodes (anode and cathode) respectively disposed on both sides of the electrolyte membrane. The electrical energy generated by the electrochemical reaction in “) is taken out to the outside through current collectors (for example, separators) respectively disposed on both sides of the MEA. Among fuel cells, polymer electrolyte fuel cells (hereinafter sometimes referred to as “PEFC (Polymer Electrolyte Fuel Cell)”) used in household cogeneration systems and automobiles, etc., are used at low temperatures. Is possible. In addition, PEFC has attracted attention as an optimal power source for electric vehicles and portable power sources because of its high energy conversion efficiency, short start-up time, and small and lightweight system.

  A single cell of PEFC includes an electrolyte membrane that is maintained in a water-containing state and exhibits proton conduction performance, and a cathode and an anode that include at least a catalyst layer, and has a theoretical electromotive force of 1.23V. However, since such low electromotive force is insufficient as a power source for electric vehicles and the like, usually, a single cell is laminated in series to form a laminated body, and end plates or the like are formed at both ends of the laminated body in the lamination direction. A fuel cell in the form of a stack formed by arranging is used. From the viewpoint of reducing the contact resistance, a fastening pressure (hereinafter sometimes referred to as “compression pressure”) is applied from both ends of the stack type fuel cell.

  During operation of the PEFC, a hydrogen-containing gas (hereinafter referred to as “hydrogen”) is supplied to the anode, and an oxygen-containing gas (hereinafter referred to as “oxygen”) is supplied to the cathode (hereinafter, hydrogen supplied to the anode). And oxygen supplied to the cathode may be collectively referred to as “reactive gas”.) The hydrogen supplied to the anode is separated into protons and electrons on the catalyst contained in the catalyst layer of the anode (hereinafter also referred to as “anode catalyst layer”), and the protons generated from the hydrogen are separated from the anode catalyst layer. And reaches the cathode catalyst layer (hereinafter also referred to as “cathode catalyst layer”) through the electrolyte membrane. On the other hand, electrons reach the cathode catalyst layer through an external circuit, and protons and electrons that have reached the cathode catalyst layer react with oxygen supplied to the cathode catalyst layer to generate water. .

  On the other hand, in many PEFCs, a diffusion layer is disposed between the separator provided on the anode side and the anode catalyst layer and / or between the separator provided on the cathode side and the cathode catalyst layer. A frame material composed of a resin or the like is arranged around the periphery (hereinafter, a diffusion layer disposed between a separator provided on the anode side and the anode catalyst layer is provided as an “anode diffusion layer” on the cathode side. The diffusion layer disposed between the separator and the cathode catalyst layer is referred to as “cathode diffusion layer”, and the anode diffusion layer and the cathode diffusion layer may be collectively referred to as “diffusion layer”. According to the PEFC in the form in which the diffusion layer is provided, it is possible to uniformly supply the reaction gas to the electrode, to improve the drainage property of discharging water generated in the MEA to the outside of the single cell during high load operation, and the like. It becomes possible to improve the water retention of the electrolyte membrane at high temperatures and the like. And the airtightness etc. in a single cell are maintained with the frame material.

Heretofore, several techniques relating to a diffusion layer for a fuel cell or a woven fabric or a substrate that can be used as a diffusion layer for a fuel cell have been disclosed. For example, Patent Document 1 discloses a woven fabric mainly woven with yarns of carbonaceous fibers having a fineness of 16 to 120 in the metric count, and the content of the carbonaceous fibers is 60% by weight or more. Disclosed is a conductive carbonaceous fiber woven fabric having an amount of 50 to 150 g / m ² , a woven fabric thickness of 0.05 mm to 0.33 mm, and a volume resistivity in the plane direction of 0.1 Ωcm or less. Yes. And this conductive carbonaceous fiber woven fabric is a thin woven fabric in which relatively thin yarns are woven so that the gap between the yarns is narrow, and the gas permeability required for the gas diffusion layer of the fuel cell, It is said that various properties such as water discharge, water retention and conductivity are satisfied at a high level in a well-balanced manner.

Patent Document 2 and Patent Document 3 disclose a technique related to a gas diffusion layer, Patent Document 4 discloses a technique related to a carbonaceous fiber woven fabric, and Patent Document 5 describes a technique related to a porous carbon electrode base material and a manufacturing method thereof. , Respectively.
JP 2003-336145 A Japanese Patent No. 3596773 JP 2003-173789 A JP 2004-100102 A Japanese Patent Laid-Open No. 2004-288889

  However, since the conductive carbon fiber woven fabric disclosed in Patent Document 1 is a woven fabric, a process of weaving warps and wefts into a fabric is required, and the manufacturing process tends to be complicated. There was a problem that it was difficult to control. In addition, since the gas diffusion layers disclosed in Patent Document 2 and Patent Document 3 are both manufactured by knitting yarn, similarly to the conductive carbonaceous fiber woven fabric disclosed in Patent Document 1, There was a problem that the manufacturing process was easily complicated and the pore diameter was difficult to control. Furthermore, since the carbon fiber woven fabric disclosed in Patent Document 4 is also a woven fabric, there is a problem that the manufacturing process is easily complicated and the pore diameter is difficult to control. In addition, since the porous carbon electrode substrate disclosed in Patent Document 5 includes a step of firing at a temperature of at least 1200 ° C., a large amount of energy is consumed during production, and the production cost is likely to increase. There was a problem.

  Accordingly, a first object of the present invention is to provide a conductive porous body and a method for manufacturing the same, which can control the pore diameter and can simplify the manufacturing process and reduce the manufacturing cost. . Furthermore, since the conductive porous body of the present invention is particularly suitably used as a fuel cell diffusion layer, the fuel cell diffusion layer capable of simplifying the production process and reducing the production cost and the production thereof Providing a method is a second problem. In addition, a third object is to provide a fuel cell and a method for manufacturing the same that can simplify the manufacturing process and reduce the manufacturing cost.

In order to solve the above problems, the present invention takes the following means. That is,
The first aspect of the present invention includes at least a first fiber group formed by arranging a plurality of first conductive fibers in a planar shape, and a plurality of second conductive fibers so as to intersect with the plurality of first conductive fibers. A conductive porous portion formed by laminating a second fiber group formed by arranging fibers in a plane, and a frame provided on an outer edge of the conductive porous portion to fix the conductive porous portion A conductive porous body.

  Here, the conductive fibers constituting the conductive porous portion including the first conductive fibers and the second conductive fibers (hereinafter referred to as the first conductive fibers and the second conductive fibers are represented by the conductive properties). Examples of the conductive fiber constituting the porous portion may be simply referred to as “conductive fiber”. Carbon, metal fiber, and the like can be exemplified. Furthermore, as a constituent material of the frame, a material that can constitute a frame material provided in the current PEFC can be used, and specific examples thereof include silicone rubber and fluorine rubber. Examples of the silicone rubber that can constitute the frame include vinyl methyl silicone rubber (VMQ) and fluorinated silicone rubber (FVMQ). Examples of the fluororubber that can constitute the frame include vinylidene fluoride rubber (FKM), tetrafluoroethylene-propylene rubber (FEPM), tetrafluoroethylene-purple olovinyl ether rubber (FFKM), and the like. Can do. In addition, the “frame body provided at the outer edge of the conductive porous portion and fixing the conductive porous portion” means that the outer edge of the conductive porous portion is surrounded by the frame body, and the conductive porous portion and the frame body are integrated. This means that the conductive porous part is fixed by the frame. The same applies to the following present invention.

  In the first aspect of the present invention, it is preferable that the frame has a function as a gasket, and the frame is provided with a recess.

  In the first aspect of the present invention (including modifications, the same applies hereinafter), it is preferable that at least a part of the frame is provided with a highly rigid substance.

  Here, the “high rigidity substance” is deformed by an external force rather than the constituent material of the frame (when the high rigidity substance is provided in the frame, it means a frame constituent material other than the high rigidity substance). It means a difficult substance, and “high rigidity material is provided on at least a part of the frame” means that the surface of the frame is provided with a high rigidity substance and high rigidity in the form of being buried inside the frame. It is a concept that includes forms in which substances are provided. The same applies to the following present invention.

  In the first aspect of the present invention, it is preferable that the interval at which the plurality of first conductive fibers are arranged is different from the interval at which the plurality of second conductive fibers are arranged. The same applies to the following present invention.

  In the first aspect of the present invention, it is preferable that the diameter of the first conductive fiber is different from the diameter of the second conductive fiber.

  The second aspect of the present invention is a fuel cell diffusion layer having the conductive porous body of the first aspect of the present invention.

  Here, when the recess of the fuel cell diffusion layer according to the second aspect of the present invention is provided with a recess, the frame positioned between the recess and the conductive porous portion is referred to as an “inner portion” of the frame, When the frame located on the side opposite to the conductive porous portion with respect to the concave portion is referred to as the “outer portion” of the frame, the conductive fibers constituting the conductive porous portion are fixed at the inner portion of the frame. . When the frame of the diffusion layer for a fuel cell according to the second aspect of the present invention is provided with a recess, the inner part of the frame is provided (that is, the conductive fiber can be fixed by a part of the frame). If it is provided, the shape of the recess is not particularly limited. As a specific example of the form of the recess, in addition to the form provided on the entire circumference of the frame (form in which the conductive porous part is surrounded by the recess sandwiched by the inner part and the outer part), it is provided only on a part of the frame. The form etc. which can be mentioned can be mentioned.

  According to a third aspect of the present invention, there is provided an electrolyte membrane, a pair of catalyst layers provided in a form for sandwiching the electrolyte membrane, a pair of diffusion layers provided in a form for sandwiching the pair of catalyst layers, A fuel cell, wherein the diffusion layer is a diffusion layer for fuel cells according to the second aspect of the present invention.

  Here, examples of the constituent material of the separator include hydrocarbon resins and metals. Furthermore, the catalyst layer means a layer comprising an ionomer having proton conductivity and a catalyst substance that functions as a catalyst for electrochemical reaction. Specific examples of ionomers having proton conductivity include fluorine ionomers (for example, Nafion, etc., “Nafion” is a registered trademark of DuPont, USA; hereinafter simply referred to as “Nafion”), and hydrocarbon-based ionomers. Examples include ionomers (for example, Selemion, etc., “Selemion” is a registered trademark of Asahi Glass Co., Ltd., hereinafter simply referred to as “Selemion”) and the like. In addition, the electrolyte membrane means a solid polymer membrane having proton conductivity. Examples of the ionomer having proton conductivity contained in the solid polymer membrane include the fluorine ionomer and the hydrocarbon ionomer. Can be illustrated.

  The fourth aspect of the present invention is a first fiber group forming step of forming a first fiber group by arranging a plurality of first conductive fibers in a planar shape, and after the first fiber group forming step, A second fiber group forming step of forming a second fiber group by arranging a plurality of second conductive fibers in a plane on the first fiber group so as to intersect the fiber direction of the first conductive fiber; And a conductive porous part forming step for forming a conductive porous part including the first fiber group and the second fiber group, and an outer edge of the conductive porous part formed by the conductive porous part forming step. A frame body forming step of forming a frame body in which a frame body material is arranged to fix the conductive porous portion. A method for producing a conductive porous body.

  Here, “a plurality of second conductive fibers are arranged in a plane on the first fiber group so as to intersect the fiber direction of the plurality of first conductive fibers to form the second fiber group”. Is a form in which the axial direction of each first conductive fiber constituting the first fiber group intersects with the axial direction of each second conductive fiber constituting the second fiber group. Means that the second fiber group is laminated. Furthermore, “to form a conductive porous part including the first fiber group and the second fiber group” means, for example, that the conductive porous part has a first fiber group to an Nth fiber group (N is a natural number of 3 or more). In the same manner, the process of forming the second fiber group on the first fiber group and forming the third fiber group on the second fiber group is repeated in the same manner. By forming up to a group, it means that a conductive porous part is formed. In addition, “a frame material is arranged on the outer edge of the conductive porous portion to form a frame that fixes the conductive porous portion” means, for example, when the frame material is a silicone resin, It means that the frame body is formed by a method in which a dissolved silicone resin is allowed to flow into a mold disposed on the outer edge of the conductive porous body, and is cooled and dried. The same applies to the following present invention.

  In the fourth aspect of the present invention, it is preferable that a compressive pressure applying step of applying a compressive pressure in the thickness direction of the conductive porous portion is provided in the conductive porous portion forming step.

  In the fourth aspect of the present invention (including modifications, the same applies hereinafter), it is preferable that the frame body forming step further includes a concave portion forming step of forming a concave portion in the frame body.

  Here, the “recess forming step of forming a recess in the frame” is formed in the frame in addition to the step of forming the recess by making a notch or the like in the frame after the frame is formed. It is a concept that includes a form in which, for example, the silicone resin or the like is allowed to flow into a mold having a convex portion corresponding to the concave portion, and cooled and dried to form a frame including the concave portion. The same applies to the following present invention.

  In the fourth aspect of the present invention, it is preferable that the frame forming step further includes a high-rigidity substance disposing step of disposing a high-rigidity substance on at least a part of the frame.

  In the fourth aspect of the present invention, the intervals between the plurality of first conductive fibers arranged in a planar shape in the first fiber group forming step, and the plurality of first electrodes arranged in a planar shape in the second fiber group forming step. The distance between the two conductive fibers is preferably different.

  In the fourth aspect of the present invention, it is preferable that the diameter of the first conductive fiber is different from the diameter of the second conductive fiber.

  5th this invention is a manufacturing method of the diffusion layer for fuel cells characterized by including the process of manufacturing an electroconductive porous body by the said 4th this invention.

  The sixth aspect of the present invention is a membrane electrode structure manufacturing step in which a catalyst layer is provided on each of the front and back surfaces of an electrolyte membrane to manufacture a membrane electrode structure, and a membrane manufactured by the membrane electrode structure manufacturing step. A laminated body manufacturing step of forming a laminated body by disposing a diffusion layer on each of one side and the other side of the electrode structure, and one side of the laminated body produced by the laminated body manufacturing step and A separator disposing step of disposing a separator on each of the other side, wherein the diffusion layer is manufactured by the method for manufacturing a diffusion layer for a fuel cell according to the fifth aspect of the present invention. This is a method of manufacturing a fuel cell.

  Here, as the membrane electrode structure production step, for example, an ink-like catalyst layer composition produced by dispersing a carrier carrying a catalyst in an ionomer having proton conductivity dissolved in a solvent, Examples include a step of producing a membrane electrode structure (hereinafter referred to as “MEA”) by screen printing on the front and back surfaces of the electrolyte membrane. In addition, the MEA can also be produced by spray-coating the catalyst layer composition onto the electrolyte membrane. Furthermore, as a laminated body production process, for example, an MEA is disposed between a pair of diffusion layers, and a laminated body is produced by thermocompression bonding the pair of diffusion layers and the MEA. .

  According to the first aspect of the present invention or the fourth aspect of the present invention, the pore diameter of the conductive porous portion can be controlled by controlling the interval between the conductive fiber groups arranged in a plane. Therefore, according to 1st this invention, the electroconductive porous body which can control a pore diameter can be provided. On the other hand, according to 4th this invention, the manufacturing method of the electroconductive porous body which can control a pore diameter can be provided. Further, according to the first invention or the fourth invention, the conductive porous group is formed by laminating the conductive fiber group, and the conductive body is made conductive by the frame disposed at the outer edge of the conductive porous part. A conductive porous body can be formed by fixing the porous portion. That is, there is no need to braid or bake conductive fibers. Therefore, according to 1st this invention, the electroconductive porous body which can simplify a manufacturing process and can reduce manufacturing cost can be provided. On the other hand, according to 4th this invention, the manufacturing method of the electroconductive porous body which can simplify a manufacturing process and can reduce manufacturing cost can be provided.

  Further, in the first invention or the fourth invention, if the frame body also has a function as a gasket, an increase in the number of parts in the device including the conductive porous body of the present invention can be reduced. Furthermore, if the frame is provided with a recess, the dimension of the conductive porous portion is changed in a direction parallel to the planar first fiber group and the second fiber group (hereinafter referred to as “plane direction”). Even if it is a case, it can suppress that the stress which causes the said dimensional change propagates to the outermost periphery part of a frame by a recessed part.

  Further, in the first invention or the fourth invention, the high-rigidity substance provided in the frame can be provided, for example, in a form capable of suppressing a dimensional change in the surface direction of the conductive porous part, If it is provided in such a form, the dimensional change in the surface direction of the conductive porous portion can be suppressed. Therefore, by adopting a configuration in which a highly rigid substance is provided, it is possible to suppress the dimensional change of the conductive porous body including the conductive porous portion, and it is possible to ensure the function of the frame body as a gasket.

  In the first invention or the fourth invention, if the interval at which the plurality of first conductive fibers are arranged is different from the interval at which the plurality of second conductive fibers are arranged, the conductive property When the porous portion is viewed from above (or below) in the stacking direction, the size of the pores can be inclined in the stacking direction. Thereby, the distribution | circulation form of the fluid which flows through the pore of an electroconductive porous part is controllable.

  Further, in the first invention or the fourth invention, if the diameter of the first conductive fiber is different from the diameter of the second conductive fiber, the conductive fiber is laminated. When the conductive porous portion is viewed from the side, the spacing between the fiber groups in the conductive fiber lamination direction (for example, the second fiber group is disposed on the first fiber group, and the second fiber group is disposed on the second fiber group. When three fiber groups are arranged, the interval between the first fiber group and the third fiber group in the stacking direction of the conductive fibers can be inclined. Thereby, the ease of distribution of the fluid flowing through the pores of the conductive porous part can be controlled.

  According to the second aspect of the invention or the fifth aspect of the invention, the pore diameter of the conductive porous portion can be controlled by controlling the interval between the conductive fiber groups arranged in a plane. Therefore, according to the second aspect of the present invention, a fuel cell diffusion layer capable of controlling the pore diameter can be provided. On the other hand, according to the fifth aspect of the present invention, it is possible to provide a method for manufacturing a diffusion layer for a fuel cell capable of controlling the pore diameter. Furthermore, according to the second aspect of the invention or the fifth aspect of the invention, the conductive porous group is formed by laminating the conductive fiber group, and the conductive body is made conductive by the frame disposed at the outer edge of the conductive porous part. A fuel cell diffusion layer can be formed by fixing the porous portion. That is, since it is not necessary to knit or bake conductive fibers, the second aspect of the present invention can provide a diffusion layer for a fuel cell that can simplify the manufacturing process and reduce the manufacturing cost. On the other hand, according to the fifth aspect of the present invention, it is possible to provide a method for manufacturing a diffusion layer for a fuel cell capable of simplifying the manufacturing process and reducing the manufacturing cost.

  Further, in the second or fifth aspect of the present invention, if the frame also has a function as a gasket, the increase in the number of components in the fuel cell including the fuel cell diffusion layer of the present invention can be reduced. it can. Furthermore, the depth direction of the concave portion of the frame and the lamination direction of the conductive fiber group (hereinafter referred to as “lamination direction”) are substantially parallel, or the depth direction of the concave portion and the lamination direction intersect at an acute angle. If the recess is provided in such a form, even if the dimension of the conductive porous portion changes in the plane direction, the stress of the dimensional change is caused by the recess in the frame body located outside the recess. Propagation to the part (outer part of the frame) can be suppressed. Therefore, by setting it as such a form, the diffusion layer for fuel cells which can maintain the airtightness of a single cell with the outer part of a frame can be provided.

  Further, in the second invention or the fifth invention, the high-rigidity substance provided in the frame can be provided, for example, in a form capable of suppressing a dimensional change in the surface direction of the conductive porous part, If it is provided in such a form, the dimensional change in the surface direction of the conductive porous part in contact with the MEA is suppressed. Therefore, the generation | occurrence | production of soot on the surface of MEA can be suppressed, and the diffusion layer for fuel cells which can suppress the power generation performance fall of the fuel cell resulting from the presence of the soot can be provided. Furthermore, if the dimensional change in the surface direction of the conductive porous portion is suppressed, the dimensional change in the surface direction of the conductive porous body is also suppressed. Therefore, the diffusion layer for a fuel cell that easily maintains the airtightness of the single cell. Can provide.

  In the second or fifth aspect of the present invention, if the interval at which the plurality of first conductive fibers are arranged and the interval at which the plurality of second conductive fibers are arranged are different, the conductive property The pore size when the porous portion is viewed from above (or below) in the stacking direction can be inclined in the stacking direction of the conductive fibers. Thereby, the distribution | circulation form of the fluid (For example, reaction gas, water, etc.) which flows through the pore of an electroconductive porous part is controllable.

  Further, in the second invention or the fifth invention, if the diameter of the first conductive fiber is different from the diameter of the second conductive fiber, the conductive fiber is laminated. The spacing between the fiber groups in the stacking direction when the conductive porous portion is viewed from the side surface (for example, the second fiber group is disposed on the first fiber group, and the third fiber group is disposed on the second fiber group. In the case where the conductive fibers are arranged, the distance between the first fiber group and the third fiber group in the stacking direction of the conductive fibers can be inclined. Thereby, the distribution | circulation form of the fluid (For example, reaction gas, water, etc.) which flows through the pore of an electroconductive porous part is controllable.

  According to the third aspect of the present invention, since the fuel cell diffusion layer according to the second aspect of the present invention is provided, a fuel cell capable of simplifying the manufacturing process and reducing the manufacturing cost can be provided. Furthermore, a fuel cell capable of producing the same effect as the above effect obtained by the second present invention can be provided. On the other hand, according to the sixth aspect of the present invention, a fuel cell is manufactured using the fuel cell diffusion layer manufactured by the method for manufacturing a fuel cell diffusion layer according to the fifth aspect of the present invention. A fuel cell that can be simplified and reduced in manufacturing cost can be provided. Furthermore, it is possible to provide a method for manufacturing a fuel cell capable of producing the same effect as that obtained by the fifth aspect of the present invention.

1. Diffusion layer for fuel cells (conductive porous material)
As described above, the conductive porous body of the present invention can be suitably used as a fuel cell diffusion layer. Here, as the constituent material of the member constituting the conductive porous body of the present invention, the same constituent material as the member constituting the fuel cell diffusion layer of the present invention can be used, and the fuel of the present invention All the descriptions relating to the battery diffusion layer also apply to the conductive porous body of the present invention. Therefore, instead of the description of the conductive porous body of the present invention, the following description of the diffusion layer for fuel cells of the present invention will be replaced with the description of the diffusion layer for fuel cells of the present invention. Reference will be made to the constituent materials of the conductive porous body and the frame of the present invention that can be used when used in applications other than the diffusion layer for fuel cells. Hereinafter, the diffusion layer for fuel cells which is one form of the electroconductive porous body of this invention is demonstrated.

  FIG. 1 is a front view schematically showing a form example of a fuel cell diffusion layer (hereinafter referred to as “diffusion layer according to a first embodiment”) according to the first embodiment of the present invention, and FIG. FIG. 2 is a view showing an XX cross section of FIG. 1. Hereinafter, the fuel cell diffusion layer of the present invention will be described with reference to FIGS. 1 and 2. In addition, in the following description, when referring to the properties common to the fiber groups constituting the conductive porous portion, it is referred to as “each fiber group” and the properties common to the conductive fibers provided in each fiber group. When referred to, it is described as “each conductive fiber”.

  As shown in FIG. 1, a diffusion layer 10 according to the first embodiment (hereinafter simply referred to as “diffusion layer 10”) is provided on a conductive porous portion 8 and an outer edge of the conductive porous portion 8 to be conductive. And a frame body 9 for fixing the porous porous portion 8. Each conductive fiber provided in the conductive porous portion 8 is a carbon fiber, and each conductive fiber constituting each fiber group is arranged in a substantially parallel, substantially equidistant, and planar form. The conductive porous portion 8 includes a first fiber group 1, a second fiber group 2 laminated on the first fiber group 1, and a third fiber group 3 laminated on the second fiber group 2. And a fourth fiber group 4 laminated on the third fiber group 3, a fifth fiber group 5 laminated on the fourth fiber group 4, and a laminate on the fifth fiber group 5. The sixth fiber group 6 and the seventh fiber group 7 laminated on the sixth fiber group 6 are provided. The first fiber group 1 is formed by arranging the first conductive fibers 1a, 1a,..., And the second fiber group 2 includes the second conductive fibers 2a, 2a,. Are arranged by arranging the second conductive fibers 2a, 2a,... So that 1a,. Further, the third fiber group 3 arranges the third conductive fibers 3a, 3a,... So that the third conductive fibers 3a, 3a,... And the second conductive fibers 2a, 2a,. The fourth fiber group 4 is formed so that the fourth conductive fibers 4a, 4a,... And the third conductive fibers 3a, 3a,. ,... Are arranged. Hereinafter, similarly, the fifth conductive fibers 5a, 5a,... Forming the fifth fiber group 5 form the sixth fiber group 6 so as to be substantially orthogonal to the fourth conductive fibers 4a, 4a,. The sixth conductive fibers 6a, 6a,... Form the seventh conductive fibers 7a, 7a,... That form the seventh fiber group 7 so as to be substantially orthogonal to the fifth conductive fibers 5a, 5a,. The six conductive fibers 6a, 6a,... Are arranged so as to be substantially orthogonal to each other.

  On the other hand, as shown in FIG. 1, the frame body 9 is provided with a recess 9 a and is a frame body (hereinafter referred to as “fiber fixing portion 9 b”) positioned between the recess 9 a and the conductive porous portion 8. Each conductive fiber constituting the conductive porous portion 8 is fixed. Further, a sealing gasket portion 9c is provided at a portion of the outer edge than the concave portion 9a, and a high-rigidity substance (hereinafter referred to as “high-rigidity material”) is formed on one surface of the frame body 9 (surface on the lower side in FIG. 2). 9d is provided.

  Thus, the conductive porous portion 8 has the second fiber group 2 disposed on the first fiber group 1, and the third fiber on the second fiber group 2 disposed on the first fiber group 1. The group 3 is arranged, and thereafter, the fourth fiber group 4, the fifth fiber group 5, the sixth fiber group 6, and the seventh fiber group 7 are sequentially arranged on the third fiber group 3. . Therefore, it is not necessary to weave each conductive fiber, and the conductive porous portion 8 can be formed by the process of laminating each fiber group, so that the productivity of the conductive porous portion 8 can be improved. Furthermore, the electroconductive porous part 8 comprised by laminating | stacking a fiber group is fixed by the frame 9 with which the outer edge is equipped. Therefore, it is not necessary to bind the conductive fibers (carbon fibers), it is not necessary to undergo a heat treatment for binding the carbon fibers, and the manufacturing cost spent for the heat treatment can be reduced. Therefore, according to the diffusion layer 10, the manufacturing process can be simplified and the manufacturing cost can be reduced.

  Further, in the diffusion layer 10, the frame body 9 is made of a silicone resin, and the frame body 9 is provided with a sealing gasket portion 9 c. Therefore, according to the diffusion layer 10 of this form, it can be used as a gasket.

  In addition, the diffusion layer 10 includes a recess 9 a in the frame body 9. Therefore, even if the dimension of the conductive porous portion 8 is changed in the left-right direction on the paper surface or the vertical direction on the paper surface in FIG. 1 by applying pressure to the conductive porous portion 8, the dimensional change is caused by the recess 9a. It can be stopped at the conductive porous portion 8 and the fiber fixing portion 9b. That is, according to the diffusion layer 10, it is possible to prevent the position of the sealing gasket portion 9 c from shifting in the horizontal direction on the paper surface or the vertical direction on the paper surface in FIG. 1, so that the function as the sealing material can be maintained.

  Furthermore, in the diffusion layer 10, the frame 9 is provided with a highly rigid material 9 d. Therefore, even if pressure is applied to the conductive porous portion 8, the highly rigid material 9d can suppress the dimensional change of the conductive porous portion 8.

  FIG. 3 is a front view schematically showing a form example of a fuel cell diffusion layer (hereinafter referred to as “diffusion layer according to a second embodiment”) according to the second embodiment of the present invention. FIG. 3 is a view showing a YY cross section of FIG. 2. 3 and 4, components having the same configuration as the members shown in FIGS. 1 and 2 are denoted by the same reference numerals as those used in FIGS. 1 and 2, and description thereof will be omitted as appropriate. Hereinafter, the fuel cell diffusion layer of the present invention will be described with reference to FIGS. 3 and 4.

  As shown in FIG. 3, the diffusion layer 20 according to the second embodiment includes a conductive porous portion 28, a frame 9 that is provided on the outer edge of the conductive porous portion 28 and fixes the conductive porous portion 28, It has. Each conductive fiber provided in the conductive porous portion 8 is a carbon fiber, and each conductive fiber constituting each fiber group is substantially parallel and the same from one end to the other end of the conductive porous portion 28. Are arranged in a planar shape in such a manner that the interval between the conductive fibers constituting the fiber group gradually increases (or decreases). The conductive porous portion 28 includes a first fiber group 21, a second fiber group 22 laminated on the first fiber group 21, and a third fiber group 23 laminated on the second fiber group 22. And a fourth fiber group 24 laminated on the third fiber group 23, a fifth fiber group 25 laminated on the fourth fiber group 24, and a laminate on the fifth fiber group 25. A sixth fiber group 26 and a seventh fiber group 27 laminated on the sixth fiber group 26. The first fiber group 21 is formed by arranging the first conductive fibers 21a, 21a,..., And the second fiber group 22 includes the second conductive fibers 22a, 22a,. Are arranged by arranging the second conductive fibers 22a, 22a,... So that 21a,. Further, the third fiber group 23 arranges the third conductive fibers 23a, 23a,... So that the third conductive fibers 23a, 23a,... And the second conductive fibers 22a, 22a,. , And the fourth conductive fiber 24a, 24a,... And the third conductive fiber 23a, 23a,... Are substantially orthogonal to each other. ,... Are arranged. Hereinafter, similarly, the fifth conductive fibers 25a, 25a,... Forming the fifth fiber group 25 form the sixth fiber group 26 so as to be substantially orthogonal to the fourth conductive fibers 24a, 24a,. The sixth conductive fibers 26a, 26a,... Form the seventh conductive group 27a, 27a,... Forming the seventh fiber group 27 so as to be substantially orthogonal to the fifth conductive fibers 25a, 25a,. The six conductive fibers 26a, 26a,... Are arranged so as to be substantially orthogonal to each other. Thus, according to the diffusion layer of the present invention that does not require braiding or baking carbon fibers, the size of the pores provided in the conductive porous portion 28 can be controlled by controlling the pitch of the arranged carbon fibers. Can be controlled easily.

  FIG. 5 is a front view schematically showing a form example of a fuel cell diffusion layer (hereinafter referred to as “diffusion layer according to the third embodiment”) according to the third embodiment of the present invention. FIG. 6 is a diagram showing a ZZ cross section of FIG. 5. 5 and 6, components having the same configuration as the members shown in FIGS. 1 and 2 are denoted by the same reference numerals as those used in FIGS. 1 and 2, and description thereof will be omitted as appropriate. Hereinafter, the fuel cell diffusion layer of the present invention will be described with reference to FIGS. 5 and 6.

  As shown in FIG. 5, the diffusion layer 30 according to the third embodiment includes a conductive porous portion 38 and a frame 9 that is provided on the outer edge of the conductive porous portion 38 and fixes the conductive porous portion 38. It has. Each conductive fiber provided in the conductive porous portion 38 is a carbon fiber. The conductive fibers constituting each fiber group are arranged substantially in parallel so that the distance between the conductive fibers constituting the fiber group increases from the bottom to the top in FIG. 6, and the bottom in FIG. It arrange | positions so that the diameter of the conductive fiber which comprises a fiber group may become large, so that it may go upwards from.

  The conductive porous portion 38 includes a first fiber group 31, a second fiber group 32 laminated on the first fiber group 31, and a third fiber group 33 laminated on the second fiber group 32. And a fourth fiber group 34 laminated on the third fiber group 33, a fifth fiber group 35 laminated on the fourth fiber group 34, and a laminate on the fifth fiber group 35. A sixth fiber group 36, and a seventh fiber group 37 laminated on the sixth fiber group 36. The first fiber group 31 is formed by arranging the first conductive fibers 31a, 31a,... At the interval P1, and the second fiber group 32 is composed of the second conductive fibers 32a, 32a,. Are formed by arranging the second conductive fibers 32a, 32a,... At intervals P2 so that the fibers 31a, 31a,. Further, the third fiber group 33 is spaced apart from the third conductive fibers 33a, 33a, ... so that the third conductive fibers 33a, 33a, ... are substantially orthogonal to the second conductive fibers 32a, 32a, .... The fourth fiber group 34 includes the fourth conductive fibers 34a, 34a,... And the third conductive fibers 33a, 33a,. 34a, 34a,... Are arranged at intervals P4. Hereinafter, similarly, the fifth conductive fibers 35a, 35a,... Forming the fifth fiber group 35 are arranged at intervals P5 so as to be substantially orthogonal to the fourth conductive fibers 34a, 34a,. The sixth conductive fibers 36a, 36a,... Forming the fiber group 36 are arranged at a distance P6 so as to be substantially orthogonal to the fifth conductive fibers 35a, 35a,. The seven conductive fibers 37a, 37a,... Are arranged at intervals P7 so as to be substantially orthogonal to the sixth conductive fibers 36a, 36a,.

  The conductive porous portion 38 satisfies P1 = P2, P3 = P4, and P5 = P6, and satisfies “P1 (= P2) <P3 (= P4) <P5 (= P6) <P7”. Each conductive fiber is arranged. Further, the fiber diameter of the first conductive fibers 31a, 31a,... Is "R1," the fiber diameter of the second conductive fibers 32a, 32a, ... is "R2," and the fibers of the third conductive fibers 33a, 33a,. The diameter of the fourth conductive fibers 34a, 34a,... Is "R4", the diameter of the fifth conductive fibers 35a, 35a, ... is "R5", and the sixth conductive fibers 36a, 36a. When the fiber diameter of the seventh conductive fibers 37a, 37a,... Is "R7", R1, R2, R3, R4, R5, R6, and R7 are "R1". The relationship <R2 <R3 <R4 <R5 <R6 <R7 ”is established.

  If the conductive porous portion 38 is configured as described above, the size of the pores is set so that the size of the pores formed by each conductive fiber gradually increases from the lower side to the upper side in FIG. Can be controlled.

  In the description of the diffusion layer according to the third embodiment, “P1 (= P2) <P3 (= P4) <P5 (= P6) <P7” and “R1 <R2 <R3 <R4 <R5 <R6 <R7”. However, the diffusion layer of the present invention is not limited to this form. For example, “P1 (= P2) <P3 (= P4) <P5 (= P6) <P7” and “R1 = R2 = R3 = R4 = R5 = R6 = R7” may be adopted. In addition, “P1 = P2 = P3 = P4 = P5 = P6 = P7” and “R1 <R2 <R3 <R4 <R5 <R6 <R7” may be adopted.

  In the above description regarding the diffusion layer for fuel cells of the present invention (hereinafter sometimes referred to as “diffusion layer of the present invention” or “diffusion layer”), the frame 9 has a recess 9a, a sealing gasket portion 9c, Although the form in which the high-rigidity material 9d is provided is illustrated, the present invention is not limited to this form, and a form in which one or more of these are not provided is also possible. However, as described later, from the viewpoint of improving the power generation performance of the fuel cell including the diffusion layer of the present invention, the frame body 9 including the recess 9a, the sealing gasket portion 9c, and the high-rigidity material 9d is provided. It is preferable that the diffusion layer is in the form of being provided.

  In the above description regarding the diffusion layer for a fuel cell of the present invention, a form in which a plurality of conductive fibers forming each fiber group is arranged in parallel is illustrated, but the present invention is not limited to such a form. . In addition to the above-described form, for example, a plurality of conductive fibers forming each fiber group may be randomly arranged within a range that does not intersect.

  In the above description of the diffusion layer for a fuel cell of the present invention, the conductive porous portion having a form formed by laminating seven fiber groups has been exemplified. However, the diffusion layer for a fuel cell of the present invention is provided. The conductive porous part is not limited to this form. The number of the fiber groups provided in the conductive porous part can be changed as appropriate according to the performance required for the diffusion layer for the fuel cell, and an arbitrary number of two or more fiber groups is provided. It is possible.

  Furthermore, in the said description regarding the diffusion layer for fuel cells of this invention, although the form in which carbon fiber is used as a conductive fiber was illustrated, the conductive fiber with which the diffusion layer for fuel cells of this invention is provided is limited to carbon fiber. Is not to be done. Any material other than carbon can be used as long as it can withstand the environment in the single cell. For example, a highly corrosive metal fibrous material having stainless steel as a base material can be used.

  In addition, in the above description of the diffusion layer for a fuel cell of the present invention, the form in which silicone resin is used as the frame is exemplified, but the material that can constitute the frame provided in the diffusion layer for the fuel cell of the present invention, It is not limited to silicone resin. The frame body can be formed of a material other than the silicone resin as long as it is a material that can fix the conductive porous portion and can withstand the environment in the single cell. As a specific example of the material, A fluororesin etc. can be mentioned.

  In the fuel cell diffusion layer of the present invention, the intervals (for example, P1 to P7) when the conductive fibers constituting the conductive porous portion are arranged are functions (gas diffusibility, wetness) as the fuel cell diffusion layer. The interval is not particularly limited as long as the drainage in the environment, the water retention in the dry environment, and the like can be expressed. Specific examples of the interval include 10 μm or more and 100 μm or less.

  Furthermore, in the fuel cell diffusion layer of the present invention, the diameters of the conductive fibers constituting the conductive porous portion (for example, the above R1 to R7) are functions as a fuel cell diffusion layer (gas diffusivity, in a wet environment). If it is a diameter which can express the drainage nature in water, the water retention in a dry environment, etc.), it will not be limited in particular. Specific examples of the diameter include 2 μm or more and 20 μm or less.

  Heretofore, the case where the conductive porous body of the present invention is used as a diffusion layer for fuel cells has been described. However, the conductive porous body of the present invention is used for applications other than the diffusion layer for fuel cells (for example, filters). Can also be used. In this case, as a constituent material of the conductive fiber provided in the conductive porous body of the present invention, in addition to the above carbon and metal, an inorganic fiber whose surface is coated with a conductive material such as carbon or metal may be exemplified. it can. Further, when the conductive porous body of the present invention is used for applications other than the diffusion layer for fuel cells, the constituent materials of the frame body provided in the conductive porous body of the present invention include the silicone resin and the fluororesin described above. Can be illustrated.

2. Fuel Cell FIG. 7 is a cross-sectional view schematically showing an embodiment of the fuel cell of the present invention, and shows an enlarged partial cross section of a single cell provided in the fuel cell of the present invention. 7, components having the same configuration as the members shown in FIGS. 1 and 2 are denoted by the same reference numerals as those used in FIGS. 1 and 2, and description thereof will be omitted as appropriate. In addition, in FIG. 7, description of the gas flow path with which a separator is equipped is abbreviate | omitted. Hereinafter, the fuel cell of the present invention will be described with reference to FIG.

  As shown in FIG. 7, a single cell (hereinafter, also referred to as “the fuel cell of the present invention” or “fuel cell”) 100 provided in the fuel cell of the present invention 100 includes an electrolyte membrane 101 and the electrolyte membrane 101. An MEA 104 having an anode catalyst layer 102 provided on one side of the electrode and a cathode catalyst layer 103 provided on the other side, a pair of diffusion layers 30, 30 disposed so as to sandwich the MEA 104, and a pair Separators 105, 106 disposed outside the diffusion layers 30, 30. The separator 105 is provided with a gas flow path through which hydrogen can be circulated, and the separator 106 is provided with a gas flow path through which oxygen can be circulated. In the fuel cell 100, the electrolyte membrane 101, the anode catalyst layer 102a, and the cathode catalyst layer 103a are provided with a fluorine ionomer represented by, for example, Nafion, and the like, and the anode catalyst layer 102a and the cathode catalyst layer 103a Is further provided with carbon carrying metal particles such as platinum which function as a catalyst for electrochemical reaction. Further, the separators 105 and 106 are made of, for example, a hydrocarbon resin.

  In the fuel cell 100, a fastening pressure is applied in the vertical direction of the drawing in FIG. Therefore, the conductive porous portion 38 is compressed in the vertical direction on the paper surface of FIG. 7, and each conductive fiber constituting the conductive porous portion 38 is bent. In this way, when each conductive fiber is bent, the movement of the one conductive fiber is restricted by the conductive fibers positioned above and below the one conductive fiber. In such a case, the diffusion layer 30 in which each conductive fiber is difficult to move can be obtained.

  During the operation of the fuel cell 100, the gas flow path provided in the separator 105 and the diffusion layer 30 (hereinafter, the diffusion layer 30 disposed between the separator 105 and the anode catalyst layer 102 is referred to as a “diffusion layer 30a”. , The diffusion layer 30 disposed between the separator 106 and the cathode catalyst layer 103 is referred to as “diffusion layer 30 b”), and hydrogen supplied to protons and electrons on the catalyst of the anode catalyst layer 102. To separate. Protons generated in this way reach the catalyst of the cathode catalyst layer 103 through the fluorine-based ionomer provided in the anode catalyst layer, the electrolyte membrane 101, and the cathode catalyst layer 103. On the other hand, electrons generated in the anode catalyst layer 102 cannot pass through the electrolyte membrane 101. Therefore, the electrons reach the catalyst of the cathode catalyst layer 103 via an external circuit. The oxygen supplied through the gas flow path provided in the separator 106 and the diffusion layer 30b reacts with protons and electrons (electrochemical reaction) on the catalyst of the cathode catalyst layer 103 to generate water. The In addition, OH radicals, OOH radicals, and the like can be generated by side reactions of the electrochemical reaction. When OH radicals or OOH radicals are generated in the fuel cell 100, the conductive porous part constituted by carbon fibers is damaged by the OH radicals, OOH radicals, etc., and the dimensions of the conductive porous part 38 change (shrinkage). There is a risk.

  However, the diffusion layers 30 and 30 (hereinafter referred to as “diffusion layer 30”) of the fuel cell 100 are provided with a highly rigid material 9d on the MEA 104 side surface. Therefore, the dimensional change of the conductive porous portion 38 can be suppressed by the high-rigidity material 9d. When the dimensional change of the conductive porous portion 38 is suppressed, the generation of soot on the surface of the MEA 104 due to the dimensional change of the conductive porous portion 38 and the like is suppressed. Can be suppressed.

  On the other hand, the frame body 9 provided in the fuel cell 100 of the present invention is made of silicone resin, and the frame body 9 is provided with a sealing gasket portion 9c. Therefore, the diffusion layer 30 can function not only as a diffusion layer but also as a gasket. Therefore, in the conventional PEFC, the diffusion layers and gaskets provided as different members can be integrated in the fuel cell 100 of the present invention, so that the number of members can be reduced as compared with the conventional PEFC. Is possible.

  Further, the diffusion layer 30 of the fuel cell 100 is provided with a recess 9a. As described above, if the diffusion layer 30 is provided with the concave portion 9a, the concave portion 9a can suppress the dimensional change of the sealing gasket portion 9c even if the size of the conductive porous portion 38 is changed. Therefore, the function of the diffusion layer 30 as a gasket can be maintained.

  Furthermore, the size of the pores of the diffusion layer 30 of the fuel cell 100 is controlled so that the pores of the conductive porous portion 38 become larger as the distance from the MEA 104 increases. Therefore, for example, even in an environment where a large amount of water exists in the fuel cell 100, water generated by the MEA 104 can be easily discharged to the separators 105 and 106. In addition, the water generated in the MEA 104 comes into contact with the separators 105 and 106 that are cooled by a cooling medium or the like that flows in a heat medium flow path (not shown), and water droplets are generated from the separators 105 and 106. The movement from 106 to the MEA 104 can be suppressed. Therefore, by adopting a configuration in which the diffusion layer 30 is provided, a fuel cell capable of suppressing the occurrence of flooding can be provided.

  Furthermore, the diffusion layer 30 of the fuel cell 100 is configured such that the diameters of the plurality of conductive fibers forming each fiber group gradually increase as the distance from the MEA 104 increases. Therefore, as the distance from the MEA 104 increases, the pores of the conductive porous portion 38 become larger, so that it is possible to provide a fuel cell that can easily suppress the occurrence of flooding.

  Further, in the fuel cell 100 of the present invention, an array of conductive fibers (hereinafter referred to as “outermost surface conductive fibers”) that form the conductive porous portions 38 of the diffusion layers 30 a and 30 b in contact with the separators 105 and 106. The form and the form of the gas flow path provided in the separators 105 and 106 disposed outside the diffusion layers 30a and 30b are not particularly limited. However, for example, when the gas flow path provided in the separator 105 is provided in parallel with the outermost surface conductive fiber of the diffusion layer 30a, a portion sandwiched by the adjacent gas flow paths (hereinafter referred to as “gas flow path convexity”). The number of the outermost conductive fibers in contact with the portion is reduced (or the number of the outermost conductive fibers present at the position facing the opening of the gas flow path is increased) and added to the diffusion layer 30a. As a result, the contact pressure of the fuel cell 100 may increase. Therefore, from the viewpoint of suppressing or preventing an increase in the contact resistance, it is preferable that the outermost surface conductive fibers of the diffusion layer 30a are arranged in a form intersecting with the gas flow path provided in the separator 105. In this way, all the outermost conductive fibers can be brought into contact with the gas flow path convex portions of the separator 105, so that an increase in contact resistance can be suppressed or prevented. Here, the angle at which the gas flow path provided in the separator 105 and the outermost surface conductive fiber of the diffusion layer 30a intersect (hereinafter referred to as “intersection angle”) is not particularly limited. From the viewpoint of obtaining an effect of suppressing increase in contact resistance by enabling efficient transmission of the fastening pressure to the outermost surface conductive fiber via the road convex portion, the crossing angle is preferably 30 ° or more, More preferably, the crossing angle is 90 °. Note that, from the viewpoint of obtaining an effect of suppressing increase in contact resistance, the gas flow path provided in the separator 105 also for the intersection angle between the gas flow path provided in the separator 106 and the outermost surface conductive fiber of the diffusion layer 30b. It is preferable to have the same configuration as the above-described crossing angle between the outermost surface conductive fibers of the diffusion layer 30a.

  In the above description regarding the fuel cell of the present invention, the mode in which the diffusion layer 30 is provided is illustrated, but the diffusion layer that can be provided in the fuel cell of the present invention is not limited to this mode, and the diffusion layer 10, the diffusion layer 20, and the like The diffusion layer of the present invention having another form may be provided.

  Furthermore, in the above description regarding the fuel cell according to the present invention, the configuration in which the concave portion 9a, the gasket portion 9c for sealing, and the diffusion layer 30 including the high-rigidity material 9d are provided is illustrated. However, the fuel cell according to the present invention is provided. The diffusion layer to be obtained is not limited to this form, and may be a form in which, for example, the recess 9a and / or the sealing gasket 9c is not provided. However, from the viewpoint of reducing the number of components provided in the fuel cell, it is preferable to have a configuration in which a diffusion layer having a frame body having a sealing gasket portion is provided, and the diffusion layer has a function as a gasket. If the size of the conductive porous portion is changed, from the viewpoint of maintaining the function as the gasket, a diffusion layer having a concave portion may be provided. preferable. Furthermore, from the viewpoint of improving the power generation performance of the fuel cell of the present invention by suppressing the change in the dimensions of the conductive porous portion 38 and suppressing the generation of wrinkles on the surface of the MEA 104, a highly rigid material is provided. It is preferable to adopt a configuration in which a diffusion layer of the form is provided.

  Further, in the above description regarding the fuel cell of the present invention, the electrolyte membrane provided with the fluorine ionomer is exemplified, but the electrolyte membrane that can be provided in the fuel cell of the present invention is not limited to this form, for example, a selemion or the like. An electrolyte membrane having a hydrocarbon ionomer may be provided. Further, the above explanation regarding the fuel cell of the present invention has exemplified the separator composed of a hydrocarbon-based resin, but the separator that can be provided in the fuel cell of the present invention is not limited to this form, for example, stainless steel The separator may be made of a metal having a base material and a high corrosion-resistant film formed on the surface thereof.

  Furthermore, in the above description regarding the fuel cell of the present invention, platinum is exemplified as the catalyst. However, the catalyst that can be provided in the fuel cell of the present invention is not limited to platinum, and includes, for example, Co and / or Ru or the like in the composition. A platinum alloy may be used. Furthermore, in the above description, a mode in which a catalyst supported on a carrier is provided is illustrated. However, the fuel cell of the present invention is not limited to this mode. For example, a catalyst that is not supported on a carrier (for example, platinum black particles) ) May be provided in the anode catalyst layer and / or the cathode catalyst layer.

3. Manufacturing method of diffusion layer for fuel cell (Manufacturing method of conductive porous body)
As described above, the conductive porous body of the present invention can be suitably used as a fuel cell diffusion layer. Here, the conductive porous body of the present invention can be manufactured by the same method as the manufacturing method of the diffusion layer for a fuel cell of the present invention. Then, it replaces with description of the electroconductive porous body of this invention with the following description regarding the manufacturing method of the diffusion layer for fuel cells of this invention. Hereinafter, the manufacturing method of the diffusion layer for fuel cells which is one form of the manufacturing method of the electroconductive porous body of this invention is demonstrated.

  FIG. 8 is a flowchart schematically showing an example of a method for manufacturing a diffusion layer for a fuel cell according to the present invention (hereinafter sometimes referred to as “the manufacturing method of the present invention”). Hereinafter, the 1st fiber group, the 2nd fiber group, the 3rd fiber group, the 4th fiber group, the 5th fiber group, the 6th fiber group are used for a conductive porous part, using the numerals used in Drawings 1-6. A case of manufacturing a diffusion layer for a fuel cell in which the seventh fiber group is provided will be described.

  As shown in FIG. 8, the method for manufacturing a diffusion layer for a fuel cell of the present invention includes a conductive porous portion forming step S <b> 1 (hereinafter referred to as “step S <b> 1”) and a frame body forming step S <b> 2 (hereinafter referred to as “ Step S2 "). The conductive porous portion forming step S1 is a first fiber group forming step S11 (hereinafter referred to as “step S11”) in which the first conductive fibers 1a, 1a,. ) And after the end of step S11, the first conductive fibers 1a, 1a,... And the second conductive fibers 2a, 2a,... Cross over the first fiber group 1 formed in step S11. , Second conductive fibers 2a, 2a,... Are arranged in a planar shape to form a second fiber group 2 and a second fiber group forming step S12 (hereinafter referred to as “step S12”). Then, after the step S12 is finished, the third conductive fibers 3a, 3a,... Are arranged in a plane on the second fiber group 2 so as to intersect with the second conductive fibers 2a, 2a,. 3rd fiber group formation process S13 (henceforth "process S13") which forms 3 fiber group 3, and 3rd fiber so that it may cross | intersect 3rd conductive fiber 3a, 3a, ... after completion | finish of process S13. A fourth fiber group forming step S14 (hereinafter referred to as “step S14”) in which the fourth conductive fibers 4a, 4a,... In the same manner, the fifth fiber group forming step S15 for forming the fifth fiber group 5 (hereinafter referred to as “step S15”) and the sixth fiber group forming step S16 for forming the sixth fiber group 6 are performed. (Hereinafter referred to as “step S16”) and formation of the seventh fiber group forming the seventh fiber group 7 Degree S17 (hereinafter referred to as "step S17".) Is provided. That is, the process S1 includes a process S11, a process S12, a process S13, a process S14, a process S15, a process S16, and a process S17. In these processes, by arranging the conductive fibers at equal intervals, A conductive porous portion 8 is formed.

  When the conductive porous portion 8 is formed by the step S1, the frame body 9 is subsequently formed on the outer edge of the conductive porous portion 8 by the step S2, and the conductive porous portion 8 is fixed by the frame body 9. As shown in FIG. 8, in step S <b> 2, a concave portion forming step S <b> 21 (hereinafter referred to as “step S <b> 21”) for forming a concave portion in the frame body 9, and a high rigidity material for disposing a high rigidity material in the frame body 9. Arrangement process S22 (henceforth "process S22") is provided.Here, as a specific example of process S2, a metal mold is formed in the outer edge of conductive porous part 8 formed by process S1. The form etc. which form the frame body 9 by the method of arrange | positioning and flowing the frame body material (for example, gel-like silicone resin etc.) which comprises the frame body 9 into the said metal mold | die, drying and hardening, etc. On the other hand, as a specific example of step S21, in addition to the form of forming the recess 9a by forming a groove in the cured frame 9, a recess having a shape corresponding to the recess 9a is provided in the mold. By the resin flowed into the mold having the recess In this case, a configuration in which the concave portion 9a is formed can be given as an example, and a specific example of the high-rigidity substance disposing step S22 is a high-rigidity to the mold before the frame material is allowed to flow into the mold. The form etc. which arrange | position a substance can be mentioned.

  In the said description regarding the manufacturing method of this invention, since it described about the method of manufacturing the diffusion layer 10, although the space | interval of each conductive fiber arranged in process S11-process S17 was made into equal intervals, the manufacturing method of this invention is the said The form is not limited. For example, when the diffusion layer 30 is manufactured, the intervals in Step S11, Step S12, Step S13, Step S14, Step S15, Step S16, Step S17 are set to P1, P2, P3, P4, P5, P6, respectively. When P7 is set, “P1 = P2, P3 = P4, P5 = P6” and “P1 (= P2) <P3 (= P4) <P5 (= P6) <P7” may be set.

  Further, when the diffusion layer 30 is manufactured, for example, the fiber diameter of the first conductive fiber is the smallest and the fiber diameter of the seventh conductive fiber is the largest, and the first conductive fiber is the first from the first fiber group. What is necessary is just to form an electroconductive porous part using the electroconductive fiber which the diameter of the electroconductive fiber which forms a fiber group becomes large toward 7 fiber groups.

  On the other hand, in the above description regarding the manufacturing method of the present invention, a mode in which the compression pressure is applied in the thickness direction (= stacking direction) of the conductive porous portion and the compression pressure applying step is not provided is shown in Step S1. Is not limited to this form. For example, when forming a diffusion layer having a conductive porous portion provided with the first fiber group to the seventh fiber group, it is possible to add a pressure application step after step S17 and then perform step S2. It is. In this way, when the diffusion layer is manufactured, a compression pressure is applied in the laminating direction of the conductive porous portion, so that the degree of freedom of movement of the conductive fibers having both ends fixed by the frame can be reduced. As a result, it is possible to obtain a diffusion layer that can maintain the size of the pores formed at the time of manufacture.

  FIG. 9 is a schematic view showing an example of the step S11, FIG. 10 is an enlarged view schematically showing the comb plates 93, 96, and 98 shown in FIG. 9, and FIG. 10 (a) is a comb plate. FIG. 10B is a front view schematically showing a part of the comb-like plate 96, and FIG. 10C schematically shows a part of the comb-like plate 98. It is sectional drawing shown. In FIG. 9, the straight arrow indicates the traveling direction of the conductive fiber. 9 and 10, the same reference numerals as those used in FIG. 2 are given to the same components as those shown in FIG. 2, and the description thereof will be omitted as appropriate. In addition, in order to prevent that a figure becomes complicated, in FIG. 9, although only three rolls are shown, the number of the rolls used by process S11 is not limited to this. Hereinafter, step S11 will be described with reference to FIG. 2, FIG. 9, and FIG.

  As shown in FIG. 9, in step S11, the tips of the first conductive fibers 1a, 1a,... Wound in a roll shape are gripped by chucks 94, 94,. ,... Are drawn to the laminating work table 97. The leading ends of the first conductive fibers 1a, 1a,... Drawn from the conductive fiber rolls 91, 91,... Pass through the tension rolls 92, 92, and the final interval at which the first conductive fibers are arranged. It reaches the comb-like plate 93 (see FIG. 10A) in which grooves 93x, 93x,. The first conductive fibers 1a, 1a,..., Whose intervals are adjusted by the comb plate 93, are then chucks 94 (hereinafter, referred to as “chuck 94a”), 94 (hereinafter, referred to as “chuck 94a”) sequentially from the left side of FIG. The tip is gripped by a chuck 94 (hereinafter referred to as “chuck 94c”) after passing through a comb-like plate 96, a laminating work table 97, and a comb-like plate 98. In this way, when the tips of the first conductive fibers 1a, 1a,... Are gripped by the chuck 94c, the first conductive fibers 1a, 1a,. Are gripped by the chuck 94b, whereby the first conductive fibers 1a, 1a,... Disposed on the laminating work table 97 are fixed at two locations. After that, when the first conductive fibers 1a, 1a,... Are cut by the cutter 95, the first conductive fibers 1a, 1a, with both ends fixed by the chucks 94b, 94c on the laminating work table 97. Are arranged in a plane.

  On the other hand, as shown in FIG. 10B, the comb-like plate 96 is formed with grooves 96x, 96x,... In such a manner that the interval gradually decreases from one end to the other end. Further, the comb-like plate 98 is formed with grooves 98x, 98x,... Having the same interval as that of the other end of the comb-like plate 96. That is, in step S11, the intervals between the first conductive fibers 1a, 1a,... Forming the first fiber group 1 are controlled by the comb-like plates 93, 96, and 98.

  FIG. 11 is a schematic diagram illustrating an example of the step S13. 11, those having the same configuration as the members shown in FIG. 2, FIG. 9, or FIG. 10 are denoted by the same reference numerals as those used in these drawings, and the description thereof is omitted as appropriate. In addition, in order to prevent a figure from becoming complicated, description of the fixing means (chuck) which fixes the both ends of the 2nd conductive fiber which comprises a 2nd fiber group is abbreviate | omitted, and for the same reason as FIG. FIG. 11 also shows only three rolls, but the number of rolls used in step S13 is not limited to this. Hereinafter, step S13 will be described with reference to FIGS.

  As shown in FIG. 11, in step S13, the tips of the third conductive fibers 3a, 3a,... Wound in a roll shape are gripped by chucks 94a, 94b,. Are pulled out onto the second fiber group 2 formed on the laminating work table 97. The third conductive fibers 3a, 3a,... Drawn from the conductive fiber rolls 91 ', 91',... Are subjected to the same steps as the first conductive fibers 1a, 1a,. The interval is adjusted, and the second fiber group 2 is arranged in a planar shape.

  FIG. 12 is a cross-sectional view schematically showing an example of the step S2. 12, components having the same configuration as the members shown in FIG. 2 or FIG. 11 are denoted by the same reference numerals as those used in these drawings, and the description thereof is omitted as appropriate. In order to prevent the figure from becoming complicated, some of the fiber groups constituting the conductive porous portion 8 and some fixing means (chuck) for fixing both ends of the conductive fibers constituting the fiber group. Description is omitted. Hereinafter, step S2 will be described with reference to FIGS.

  As shown in FIG. 12, in step S <b> 2, a mold 99 that can allow the resin to flow is disposed on the outer edge of the conductive porous portion 8 formed on the stacking work table 97. The mold 99 is provided with a concave portion 99a for forming the concave portion 9a and a convex portion 99b for forming the sealing gasket portion 9c. A rigid material 9d is arranged. In step S2, a concave portion 99a and a convex portion 99b are formed in the mold to form the mold 99 (step S21), and then a highly rigid material 9d is placed in the mold 99 (step S22). And after flowing resin into the metal mold | die 99 with which high-rigidity material 9d is arrange | positioned, the frame 9 is formed by drying and hardening resin, and each conductive fiber which protruded from the frame 9 is made into The diffusion layer 10 is manufactured by cutting. By passing through this process, the frame body 9 can be arrange | positioned in the outer edge of the electroconductive porous part 8 formed by process S1, and also the electroconductive porous part 8 can be fixed with the said frame body 9. .

4). Fuel Cell Manufacturing Method FIG. 13 is a flowchart schematically showing an embodiment of the fuel cell manufacturing method of the present invention. Hereinafter, the method for manufacturing the fuel cell of the present invention will be described with reference to FIGS. 1, 7, 8, and 13.
As shown in FIG. 13, the fuel cell manufacturing method of the present invention includes an MEA manufacturing step S131 in which an MEA 104 is manufactured by disposing catalyst layers 102 and 103 on the front and back surfaces of an electrolyte membrane 101, and the step S131. A laminated body production step S132 in which diffusion layers 30 and 30 are provided on each of one side and the other side of the MEA 104 produced in the above-described manner to produce a laminated body, and the laminated body produced in the step S132. A separator disposing step S133 for disposing separators 105 and 106 is provided on each of one side and the other side.

  In the method for producing a fuel cell of the present invention, as a specific example of the MEA production step S131, for example, an ink produced by dispersing a carrier carrying a catalyst in an ionomer having proton conductivity dissolved in a solvent. The process etc. which produce MEA104 by screen-printing on the surface and back surface of the electrolyte membrane 101 can be mentioned. In addition, the MEA 104 can be produced by spray-coating the catalyst layer composition onto the electrolyte membrane 101. On the other hand, as a specific example of the stacked body manufacturing step S132, the MEA 104 is disposed between the pair of diffusion layers 30 and 30, and the pair of diffusion layers 30 and 30 and the MEA 104 are thermocompression bonded to manufacture the stacked body. And the like.

It is a front view which shows roughly the example of the form of the diffusion layer for fuel cells of this invention concerning 1st Embodiment. It is a figure which shows the XX cross section of FIG. It is a front view which shows roughly the example of the form of the diffusion layer for fuel cells of this invention concerning 2nd Embodiment. It is a figure which shows the YY cross section of FIG. It is a front view which shows roughly the example of the form of the diffusion layer for fuel cells of this invention concerning 3rd Embodiment. It is a figure which shows the ZZ cross section of FIG. It is sectional drawing which shows schematically the example of a form of the fuel cell of this invention. It is a flowchart which shows roughly the example of the form of the manufacturing method of the diffusion layer for fuel cells concerning this invention. It is the schematic which shows the form of 1st fiber group formation process S11. FIG. 10A is a front view schematically showing the comb plate 93. FIG. 10B is a front view schematically showing the comb plate 96. FIG. 10C is a front view schematically showing the comb plate 98. It is the schematic which shows the form of 3rd fiber group formation process S13. It is the schematic which shows the form of frame body formation process S2. 3 is a flowchart schematically showing an example of a method for manufacturing a fuel cell according to the present invention.

Explanation of symbols

1, 21, 31 First fiber group 1a, 21a, 31a First conductive fiber 2, 22, 32 Second fiber group 2a, 22a, 32a Second conductive fiber 3, 23, 33 Third fiber group 3a, 23a , 33a Third conductive fiber 4, 24, 34 Fourth fiber group 4a, 24a, 34a Fourth conductive fiber 5, 25, 35 Fifth fiber group 5a, 25a, 35a Fifth conductive fiber 6, 26, 36 Sixth fiber group 6a, 26a, 36a Sixth conductive fiber 7, 27, 37 Seventh fiber group 7a, 27a, 37a Seventh conductive fiber 8, 28, 38 Conductive porous part 9 Frame 9a Recessed part 9b Fiber fixing Part 9c Gasket part for sealing 9d High rigidity material (High rigidity substance)
10, 20, 30 Diffusion layer for fuel cell 100 Fuel cell 101 Electrolyte membrane 102 Anode catalyst layer 103 Cathode catalyst layer 104 MEA
105, 106 Separator 107, 108 Gas flow path

Claims (15)

At least a first fiber group formed by arranging a plurality of first conductive fibers in a plane and a plurality of second conductive fibers arranged in a plane so as to intersect with the plurality of first conductive fibers A conductive porous portion formed by laminating the second fiber group formed and a frame body that is provided at an outer edge of the conductive porous portion and fixes the conductive porous portion. A conductive porous body characterized by the following. The conductive porous body according to claim 1, wherein the frame body has a function as a gasket, and the frame body includes a recess. The conductive porous body according to claim 1, wherein a highly rigid substance is provided on at least a part of the frame. The interval at which the plurality of first conductive fibers are arranged is different from the interval at which the plurality of second conductive fibers are arranged, according to any one of claims 1 to 3. Conductive porous body. The conductive porous body according to any one of claims 1 to 4, wherein a diameter of the first conductive fiber is different from a diameter of the second conductive fiber. The diffusion layer for fuel cells which has the electroconductive porous body of any one of Claims 1-5. An electrolyte membrane, a pair of catalyst layers provided in a form for sandwiching the electrolyte membrane, a pair of diffusion layers provided in a form for sandwiching the pair of catalyst layers, and a form for sandwiching the pair of diffusion layers And a pair of separators provided in the fuel cell, wherein the diffusion layer is the fuel cell diffusion layer according to claim 6. A first fiber group forming step of forming a first fiber group by arranging at least a plurality of first conductive fibers in a plane; and
After the first fiber group forming step, a plurality of second conductive fibers are arranged in a plane on the first fiber group so as to intersect the fiber direction of the plurality of first conductive fibers. Forming a two-fiber group, a second fiber group forming step, and forming a conductive porous part including the first fiber group and the second fiber group,
A frame body forming step in which a frame body material is disposed on an outer edge of the conductive porous portion formed by the conductive porous portion forming step to form a frame body that fixes the conductive porous portion. A method for producing a conductive porous material. The method for producing a conductive porous body according to claim 8, further comprising a compressive pressure applying step of applying a compressive pressure in a thickness direction of the conductive porous portion in the conductive porous portion forming step. Method. Furthermore, the manufacturing method of the electroconductive porous body of Claim 8 or 9 with which the said frame body formation process is equipped with the recessed part formation process which forms a recessed part in the said frame body. Furthermore, the said frame body formation process is equipped with the highly rigid substance arrangement | positioning process which arrange | positions a highly rigid substance to at least one part of the said frame, The any one of Claims 8-10 characterized by the above-mentioned. The manufacturing method of the electroconductive porous body of description. The interval between the plurality of first conductive fibers arranged in a planar shape in the first fiber group forming step and the interval between the plurality of second conductive fibers arranged in a planar shape in the second fiber group forming step. The method for producing a conductive porous body according to any one of claims 8 to 11, characterized in that: The method for producing a conductive porous body according to any one of claims 8 to 12, wherein a diameter of the first conductive fiber is different from a diameter of the second conductive fiber. A method for producing a diffusion layer for a fuel cell, comprising the step of producing a conductive porous body by the method for producing a conductive porous body according to any one of claims 8 to 13. A membrane electrode structure production step of producing a membrane electrode structure by disposing a catalyst layer on each of the front and back surfaces of the electrolyte membrane;
A laminated body producing step of producing a laminated body by disposing a diffusion layer on each of one side and the other side of the membrane electrode structure produced by the membrane electrode structural body producing step;
A separator disposing step of disposing a separator on each of one side and the other side of the laminate prepared by the laminate preparing step,
The method for producing a fuel cell, wherein the diffusion layer is produced by the method for producing a diffusion layer for a fuel cell according to claim 14.

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