CN101874322B - Composite electrolyte membrane, membrane-electrode assembly, fuel cell, and methods for manufacturing same - Google Patents

Abstract

A method for manufacturing a composite electrolyte membrane including: a first folding process of folding a laminate (10A) obtained by laminating and integrating an electrolyte sheet (11) having an electrolyte as an electrolyte layer and a reinforcing sheet (12) having a porous polymer material as a reinforcing layer, so that a part of a surface of the laminate (10A) lies on another part of the surface; an impregnation process of impregnating the electrolyte of the folded laminate (10B) into the reinforcing layer; and a hydrolysis process of hydrolyzing the electrolyte impregnated in the laminate (10C).

Description

Composite electrolyte membrane, membrane electrode assembly, fuel cell and method for manufacturing them

technical field

The present invention relates to composite electrolyte membranes, membrane electrode assemblies, fuel cells and methods for their manufacture, and more particularly to composite electrolyte membranes having at least an electrolyte layer composed of an electrolyte and a reinforcement layer in which a porous polymer material is impregnated with the electrolyte Type electrolyte membrane, membrane electrode assembly, fuel cell and methods for manufacturing them.

Background technique

A solid polymer type fuel cell using an electrolyte membrane has been studied for application to a movable body such as an automobile because it operates at a low temperature and has a small size and weight. In particular, social interest in fuel cell vehicles mounted with solid polymer type fuel cells as eco-friendly vehicles is growing.

As shown in FIG. 14, the solid polymer fuel cell has a membrane electrode assembly (MEA) 95 as a main structural element. A single fuel cell 90 called a unit cell is formed by sandwiching a membrane electrode assembly between separators 96 having fuel (hydrogen) gas flow paths and air flow paths. The membrane electrode assembly 95 has a structure in which an anode side electrode (anode catalyst layer) 93a is laminated on one side of an electrolyte membrane 91 which is an ion exchange membrane, and a cathode side electrode (cathode catalyst layer) 93b is laminated on the other side, and Corresponding diffusion layers 94a, 94b are arranged at the anode catalyst layer 93a and the cathode catalyst layer 93b.

In order to ensure the strength of the membrane, the electrolyte membrane 91 has a reinforcement layer composed of a porous polymer material such as polytetrafluoroethylene (PTFE), and the reinforcement layer is impregnated with an electrolyte. This composite type electrolyte membrane having a reinforcement layer is produced by a cast film forming method shown in FIG. 13A, which is disclosed in Japanese Patent Application Publication No. 2006-147257 (JP-A-2006-147257).

More specifically, first, an electrolyte including an electrolytic polymer and a solvent is coated on one side of the backing sheet 81 being conveyed, and the electrolyte is dried. A reinforcing sheet 82 of porous polymer material is then disposed on the surface of the dried electrolyte layer. Electrolyte is impregnated into the porous polymer material from one surface of the reinforcing sheet 82 at least by applying pressure to the electrolyte layer and the reinforcing sheet 82 in this configured state. Then, the electrolyte is coated on the other surface of the reinforcing sheet 82 and dried, thus a composite electrolyte membrane 91 can be produced, wherein at least the reinforcing layer made of a porous polymer material and the electrolyte impregnated in the reinforcing layer Set on the base sheet 81.

In the composite electrolyte membrane 91 produced in the above manner, as shown in FIG. 13B, for example, the anode catalyst layer 93a and the cathode catalyst layer 93b that have been formed on the backing sheet 81 are removed by using tools and applying heat and pressure. transfer, and the catalyst layers 93a, 93b are further formed on the surface of the composite electrolyte membrane 91.

However, in the cast film forming method described above, the electrolyte is impregnated into both surfaces of the reinforcing sheet in different processes. As a result, although the same electrolyte containing an electrolytic polymer and a solvent is used, dispersion (spread) of membrane characteristics may occur between both surface sides of the composite electrolyte membrane, and it is difficult to obtain uniform characteristics.

In addition, since the manufacturing process includes coating an electrolyte on each surface and drying a solvent, it is sometimes difficult to obtain an electrolyte membrane having a uniform film thickness with high precision. In addition, the position of the reinforcement sheet relative to the electrolyte to be applied may deviate from the desired position corresponding to the precision of the manufacturing equipment. This shift is particularly prone to occur in anode and cathode catalyst layer configurations.

In this way, when uniform membrane characteristics are not obtained on both surfaces of the electrolyte membrane, and when the thickness of the electrolyte membrane and the position of the catalyst layer are not within the desired accuracy range, poor assembly may result during battery manufacturing, or Dispersions in fuel cell performance may occur during power generation.

Contents of the invention

The present invention provides a composite electrolyte membrane in which the uniformity of electrolyte characteristics in the membrane is improved and which can be manufactured with stable dimensional accuracy, a membrane electrode assembly, a fuel cell and a methods of making them.

The method for manufacturing a composite electrolyte membrane according to the first aspect of the present invention includes a first folding process of folding a laminate such that a part of a surface of the laminate is positioned on another part of the surface, the laminate being formed by obtained by laminating and integrating an electrolyte sheet having an electrolyte as an electrolyte layer and a reinforcing sheet including a porous polymer material as a reinforcing layer; impregnating the electrolyte of the folded laminated body to the reinforcement an impregnation step in a layer; and a hydrolysis step of hydrolyzing the electrolyte impregnated in the laminate.

Furthermore, in the method for manufacturing a composite electrolyte membrane according to the first aspect, in the lamination step, the laminated body may be formed by heating and laminating the electrolyte sheet and the reinforcing sheet.

Furthermore, in the method for producing a composite electrolyte membrane according to the first aspect, in the impregnating step, the folded laminated body may be heated until the electrolyte is dissolved, and the electrolyte may be impregnated to the in the reinforcement layer.

With the method for manufacturing a composite electrolyte membrane according to the above aspect, a laminate including the reinforcement layer and the electrolyte layer can be formed by integrating the electrolyte sheet and the reinforcement sheet by bonding in the lamination process. The method for laminating the two sheets is not particularly limited as long as a laminate can be formed, and a part of the electrolyte sheet may be impregnated into one surface of the reinforcement sheet by heating and pressing the electrolyte sheet.

Furthermore, in the first folding process, the laminated body is folded such that one part of the surface of the laminated body is located on another part, that is, each part of the surface on the reinforcement layer side is located at least on each other, or at least Parts of the surface on the electrolyte layer side lie at least on top of each other. In the process of folding the laminate, the surfaces that are brought into contact by folding may be bonded by heating and pressing. Preferably, the folding is performed around the central axis of the laminated body so that two equal surfaces lie on each other, but the number of foldings and the folding method are not particularly limited as long as the two sides of the electrolyte membrane are subjected to the second folding process described below. It is sufficient that the electrolyte on the surface is uniform.

In the impregnation process, the folded laminate is heated at least until the electrolyte melts, and the electrolyte is impregnated into the porous reinforcement layer. In this immersion process, pressurization to a laminated body may be performed together with heating. As a result, the electrolyte of the individual electrolyte sheets employed in the lamination stage is disposed on both surfaces of the stack. In the hydrolysis step, an ion exchange function can be imparted to the electrolyte by hydrolyzing the electrolyte impregnated in the laminate.

With this method for manufacturing a composite type electrolyte membrane, it is not necessary to position three sheets on both surfaces of the reinforcing sheet for sandwiching the electrolyte sheet. Therefore, positioning accuracy is increased, and the quality of the electrolyte membrane is stabilized. In addition, since the laminate is folded and the electrolyte of the individual electrolyte sheets is impregnated, a uniform electrolyte can be disposed on both surfaces of the composite electrolyte membrane (electrolyte membrane). In addition, the thickness of the electrolyte membrane is also stabilized. In this way, the uniformity of electrolyte characteristics is improved within the electrolyte membrane, a high-precision electrolyte membrane can be obtained, and fuel cell performance can be stabilized.

In addition, the shape, thickness, etc. of the "electrolyte sheet" and "reinforcing sheet" as referred to in the description of the present invention are not particularly limited as long as they can be folded after lamination, and the meaning includes films, films etc. As used herein, a "reinforcing sheet" is a sheet composed of a porous polymer material for the purpose of strengthening the electrolyte membrane, and a "reinforcing layer" is a sheet of porous polymer material for the purpose of strengthening the electrolyte membrane. And at least a layer formed in the thickness direction of the electrolyte membrane, and its meaning also includes a layer obtained by impregnating a polymer material with an electrolyte. In addition, "composite type electrolyte membrane" refers to a layer including at least an electrolyte layer including an electrolyte and a reinforcement layer in which a porous polymer material is impregnated with an electrolyte.

In the method for manufacturing a composite electrolyte membrane according to the first aspect, in the first folding step, the laminated body may be folded such that a part of the surface of the laminated body on the electrolyte layer side on another part of the surface. According to the above aspect, since the laminated body is folded in the first folding process so that a part of the surface of the laminated body on the electrolyte layer side is located on the other part of the surface and the reinforcement layer side becomes the surface of the electrolyte membrane, in the dipping process The reinforcement layer may be disposed in a surface layer portion close to the surface in the thickness direction of the electrolyte membrane. As a result, the creep performance of the electrolyte membrane during fuel cell operation can be improved.

In the method for manufacturing a composite electrolyte membrane according to the first aspect, in the first folding step, the laminated body may be folded such that a part of the surface of the laminated body on the reinforcing layer side on another part of the surface. According to the above aspect, since the laminated body is folded in the first folding process so that a part of the surface of the laminated body on the reinforcement layer side is located on the other part of the surface and the electrolyte layer side becomes the surface of the electrolyte membrane, in the dipping process The electrolyte layer is formed in the surface layer in the thickness direction and the position of the reinforcing layer is stabilized. As a result, in a fuel cell equipped with the electrolyte membrane, the electrolyte layer of the surface layer suppresses the dispersion of water movement within the surface of the electrolyte membrane during power generation. In addition, the adhesion of the electrolyte layer and the catalyst layer can be improved, and the performance can be stabilized.

Any molten polymer can be used as the electrolyte (precursor polymer) according to the above-described embodiments, as long as it is not thermally deteriorated and can impart an ion exchange function after hydrolysis. Examples of polymers that may be advantageously used include perfluoroproton exchange resins of fluoroalkyl copolymers having fluoroalkyl ether side chains and perfluoroalkyl backbones. Specific examples include Nafion (trade name, manufactured by Du Pont Co.), Aciplex (trade name, manufactured by Asahi Chemical Industry Co., Ltd.), Fremion (trade name, manufactured by Asahi Glass Co.), and Goaselect (trade name, manufactured by Japan manufactured by Goatex Co., Ltd.). Other examples include partial fluororesins such as polymers of trifluorostyrenesulfonic acid and polymers obtained by introducing sulfonic acid groups into polyvinylidene fluoride. Hydrocarbon proton exchange resins, polyimide resins and the like in which sulfonic acid groups are introduced into styrene-divinylbenzene copolymers can also be used. The polymer must be appropriately selected depending on the use or environment in which the fuel cell is used, but from the viewpoint of fuel cell life, perfluororesins are preferable.

It is essential that the reinforcing sheet does not dissolve during the electrolyte impregnation process. Reinforcement sheets comprising waterproof polymers are particularly preferred. The reinforcement sheet including the water-repellent polymer is effective in preventing water that has condensed and accumulated in the solid polymer type fuel cell from being supplied to electrode reaction products. Fluorine resins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) are particularly preferred because of their high water resistance ability. Fluorine-free films such as polyethylene terephthalate, polyethylene, polypropylene, and polyimide can also be used.

In the method for manufacturing a composite electrolyte membrane according to the first aspect, when the laminated body is folded in the folding process as described above so that a part of the surface on the reinforcing layer side is positioned on the other part of the surface, in the In the lamination step, after the laminate is formed, at least one of a radical inhibitor and a water-retaining material that decomposes hydrogen peroxide into water and oxygen and suppresses generation of hydroxyl radicals may be disposed on the surface of the reinforcing layer. By.

Furthermore, in the method for manufacturing a composite electrolyte membrane according to the first aspect, when the laminate is folded in the folding process as described above so that a part of the surface on the reinforcing layer side is located on the other part of the surface, the In the lamination process, at least one of a radical inhibitor and a water-retaining material that decomposes hydrogen peroxide into water and oxygen and suppresses generation of hydroxyl radicals may be disposed between the electrolyte sheet and the reinforcing sheet. .

According to the above aspect, in the first folding process, at least one additive from among the radical inhibitor and the water-retaining material is sandwiched, and then the additive is added to the electrolyte at the center of the electrolyte membrane in the thickness direction in the impregnating process. . Therefore, additives can be fixed.

As a result, the additive can be prevented from moving or flowing out due to movement of water during fuel cell power generation. When a radical inhibitor is used, the radical inhibitor decomposes hydrogen peroxide generated as a by-product during fuel cell power generation into water and oxygen by utilizing the movement of water in the electrolyte membrane in the hydrolysis process. As a result, the generation of hydroxyl radicals can be suppressed, the electrolyte membrane is stabilized, and its deterioration can be suppressed. On the other hand, when a water-retaining material is arranged, its water retention and diffusion effects can be obtained, and a decrease in fuel cell performance caused by deterioration of proton conductivity can be effectively suppressed.

The radical inhibitor referred to in the description of the present invention is "a material for decomposing hydrogen peroxide generated as a by-product during fuel cell power generation into water and oxygen and suppressing generation of hydroxyl radicals". Examples thereof include oxides of transition metals such as cerium, ruthenium, silver, tungsten, palladium, rhodium, zirconium, yttrium, manganese, molybdenum, lead, vanadium, and titanium. The water-retaining material is not particularly limited as long as it can absorb water. Examples thereof include particles or fibers composed of water-absorbing polymeric materials such as polystyrenesulfonic acid and cellulose, and water-absorbing inorganic materials such as silica and titanium oxide.

Such radical inhibitors and water-retaining materials may be uniformly disposed on the surface of the reinforcing layer by coating processes such as diecoating or spray coating and physical vapor deposition (PVD) processes such as sputtering. Since the radical inhibitor and the water-retaining material are sandwiched in the first folding process as described above, the arrangement method thereof is not particularly limited as long as they can be sandwiched in the reinforcing layer to the extent that they will not come off during folding. Can.

When the fine powdery material is used as the radical inhibitor and water retention material, the particle size of the fine powdery material is preferably larger than the pore size of the pores formed in the reinforcing sheet. With such a particle size, the pulverulent material can advantageously be sandwiched during the first folding process.

The method for manufacturing a membrane electrode assembly according to the second aspect of the present invention includes the method for manufacturing a composite electrolyte membrane according to the first aspect, wherein, in the lamination process, after the laminate has been formed, the an anode catalyst layer and a cathode catalyst layer are arranged on a surface of the electrolyte layer; and in the first folding step, folding the laminate such that the anode catalyst layer is arranged on one surface of the laminate, On the other hand, the cathode catalyst layer is arranged on the other surface of the laminate.

With the method for manufacturing a membrane electrode assembly according to the above purpose, since the anode catalyst layer and the cathode catalyst layer are formed in the same surface in which the electrolyte layer has been formed in the laminate obtained by the lamination process, these can be precisely arranged catalyst layer. As a result, distortion of the mutual arrangement of the anode catalyst layer and the cathode catalyst layer can be suppressed while maintaining the accuracy of the folded position of the laminate in the first folding process. In addition, the above-mentioned diffusion layer may be disposed after the catalyst layer has been formed. By employing the membrane electrode assembly manufactured in the above manner, it is possible to prevent poor assembly from occurring when the membrane electrode assembly is assembled into a fuel cell, and to suppress dispersion of fuel cell performance during power generation.

The method for manufacturing a membrane electrode assembly according to the third aspect of the present invention includes the method for manufacturing a composite electrolyte membrane according to the first aspect, wherein, in the lamination step, a strip-shaped laminate is formed, and in the After the stack has been formed, disposing an anode catalyst layer and a cathode catalyst layer on the surface of the electrolyte layer such that the anode catalyst layer and the cathode catalyst layer are formed in a lateral direction of the stack; and In a folding process, the laminate is folded in the longitudinal direction such that the anode catalyst layer is arranged on one surface of the laminate and the cathode catalyst layer is arranged on the other surface of the laminate.

In the method for manufacturing a membrane electrode assembly according to the third aspect of the present invention, in the stacking step, the anode catalyst layer and the cathode catalyst layer may be configured such that a plurality of the anode catalyst layers and a plurality of The cathode catalyst layers are alternately formed along the longitudinal direction.

With the method for manufacturing a membrane electrode assembly according to the above aspect, since the anode catalyst layer and the cathode catalyst layer are formed in the lateral direction in the same surface (wherein the electrolyte layer has been formed in the laminated body obtained by the lamination process), it is possible to precisely These catalyst layers are arranged without displacement so as to sandwich the composite electrolyte membrane. As a result, distortion of the mutual arrangement of the anode catalyst layer and the cathode catalyst layer can be suppressed while maintaining the accuracy of the folded position of the laminate in the first folding step, and assembly failure can be prevented when the membrane electrode assembly is assembled into a fuel cell. , and dispersion of fuel cell performance during power generation can be suppressed.

In addition, since the folding process is performed when the anode catalyst layer and the cathode catalyst layer are arranged such that a plurality of anode catalyst layers and a plurality of cathode catalyst layers are alternately formed in the longitudinal direction, a plurality of strip-shaped MEAs can be manufactured simultaneously.

The method for manufacturing a membrane electrode assembly according to the third aspect of the present invention may further include folding the stacked body in the transverse direction after the hydrolysis step such that the anode catalyst layer is adjacent to the anode catalyst layer in the longitudinal direction. A second folding process in which the cathode catalyst layers of the anode catalyst layers face each other.

According to the present invention, by performing the second forming process on the belt-shaped MEA manufactured by the above-mentioned manufacturing method, a single fuel cell in which the catalyst layer is formed without displacement can be easily obtained from one MEA without stacking (stacking) A plurality of membrane electrode assemblies, if separators are arranged between facing electrode layers.

Furthermore, since a plurality of anode catalyst layers and a plurality of cathode catalyst layers are alternately formed in the longitudinal direction and thus the cathode catalyst layers are necessarily formed adjacent to the anode catalyst layer in the longitudinal direction, by performing the second folding process, a plurality of catalyst layers having the same An anode catalyst layer with a surface facing in the same direction as the anode catalyst layer, and a plurality of cathode catalyst layers having a surface opposite to the anode catalyst layer in the same direction. As a result, assembly errors of the anode catalyst layer and the cathode catalyst layer in the membrane electrode assembly can be reliably prevented in the case of laminating a plurality of membrane electrode assemblies through typical processes.

A method for manufacturing a fuel cell according to a fourth aspect of the present invention is a method for manufacturing a fuel cell including the method for manufacturing a membrane electrode assembly according to the third aspect, and may include a diffusion layer and a separator arranging process, so The diffusion layer and separator arranging step arranges a diffusion layer on the surface of the anode catalyst layer and the surface of the cathode catalyst layer of the membrane electrode assembly after the second folding step, and A separator is arranged between the anode catalyst layer and the cathode catalyst layer of the diffusion layer, and a fuel gas flow path and an oxygen flow path are formed in the separator, so that the fuel gas flow path is located between the anode catalyst layer and the anode catalyst layer. layer side, while the oxygen flow path is located on the cathode catalyst layer side.

With the method for manufacturing a fuel cell according to the above aspect, the separator can be configured to be inserted toward the flow line in the lateral direction of the membrane electrode assembly after the second folding process, and a single fuel cell can be easily obtained. In this way, the number of production steps can be reduced compared to a typical method of disposing separators between a plurality of membrane electrode assemblies. In addition, the separators may be arranged in a continuous manner after the second folding process. Therefore, the incorporation of pollutants in the process of obtaining a single fuel cell can be suppressed.

Furthermore, when arranging the diffusion layer and the separator, it is preferable to arrange the separator having the diffusion layer formed on its surface in the membrane electrode assembly because the diffusion layer and the separator can be arranged in the membrane electrode assembly at the same time. However, the method is not limited, and the diffusion layer and the separator may be separately arranged as long as the diffusion layer and the separator can be arranged in the membrane electrode assembly and a fuel cell can be manufactured.

In addition, the arrangement of the catalyst layer can be performed by blowing the catalyst by spraying, and it is also possible to arrange the catalyst layer on the substrate sheet and transfer the catalyst layer to the electrolyte layer using a tool or a coating die under heat and pressure. In the case of using a catalyst layer ionomer as a precursor polymer, a membrane electrode assembly can be advantageously manufactured without thermal degradation of the ionomer in a subsequent impregnation process. More preferably, the electrolyte contained in the catalyst layer is a precursor of a fluorine-containing electrolyte.

In addition, a gas diffusion layer generally used in a fuel cell can be used as the diffusion layer without particular limitation. Examples of such a gas diffusion layer include a carbon fiber sheet and a porous conductive sheet used as constituent materials containing a conductive substance as a main component. Conductive particles such as carbon particles may be bonded to the sheet using a hydrophobic resin as bonding material. Furthermore, in addition to having a gas flow path formed therein, the separator may suitably have a structure that discharges water generated during power generation and circulates a coolant so as to suppress the gas flow in the fuel cell during power generation. fever.

The composite electrolyte membrane according to the fifth aspect of the present invention has at least an electrolyte layer and a reinforcement sheet, the electrolyte layer includes an electrolyte, and a porous polymer material is impregnated with the electrolyte in the reinforcement sheet, the composite electrolyte membrane including at least: an added layer in which at least one of a radical inhibitor that decomposes hydrogen peroxide into water and oxygen and suppresses generation of hydroxyl radicals and a water-retaining material is added to the electrolyte; formed as the reinforcing layer sandwiching the added layer; and the electrolyte layer formed on a surface of each of the reinforcing layers.

The composite electrolyte membrane according to the sixth aspect of the present invention has at least an electrolyte layer and a reinforcement layer, the electrolyte layer includes an electrolyte, and a porous polymer material is impregnated with the electrolyte in the reinforcement layer, and the composite electrolyte membrane includes at least : a first electrolyte layer as the electrolyte layer; an additive layer formed to sandwich the first electrolyte layer, in which hydrogen peroxide is decomposed into water and oxygen and generation of hydroxyl radicals is suppressed At least one of a free radical inhibitor and a water-retaining material is added to the electrolyte; the reinforcement layer is formed on the surface of the added layer; and the reinforcement layer is used as the electrolyte layer and is formed on the reinforcement layer A second electrolyte layer on the surface.

With the composite electrolyte membrane according to the above aspect, by forming the additive layer to which at least one additive selected from radical inhibitors and water-retaining materials is added as described above, these materials can be suppressed when water moves during fuel cell power generation. movement and flow losses.

The composite electrolyte membrane according to the seventh aspect of the present invention includes at least a pair of anode catalyst layer and cathode catalyst layer, and the anode catalyst layer and the cathode catalyst layer are arranged on both surfaces of the composite electrolyte membrane, so that the anode catalyst layer layer and the cathode catalyst layer sandwich the composite electrolyte membrane in which a reinforcement sheet comprising a porous polymer material is impregnated with an electrolyte sheet comprising an electrolyte, wherein the membrane The electrode assembly is a strip-shaped membrane electrode assembly, and a plurality of the anode catalyst layers and a plurality of the cathode catalyst layers are alternately formed on the surface of the membrane electrode assembly in a longitudinal direction.

The composite electrolyte membrane according to the eighth aspect of the present invention has at least a pair of anode catalyst layer and cathode catalyst layer arranged on both surfaces of the composite electrolyte membrane according to the fifth aspect, so that Sandwiching the composite electrolyte membrane, wherein the membrane electrode assembly is a belt-shaped membrane electrode assembly, and the anode catalyst layers and the cathode catalyst layers are alternated in the longitudinal direction on the surface of the membrane electrode assembly form.

The composite electrolyte membrane according to the ninth aspect of the present invention has at least a pair of anode catalyst layer and cathode catalyst layer arranged on both surfaces of the composite electrolyte membrane according to the sixth aspect, so that Sandwiching the composite electrolyte membrane, wherein the membrane electrode assembly is a belt-shaped membrane electrode assembly, and the anode catalyst layers and the cathode catalyst layers are alternated in the longitudinal direction on the surface of the membrane electrode assembly form.

With the membrane electrode assembly of the above aspect, since a plurality of anode catalyst layers and a plurality of cathode catalyst layers are formed on the surface of the membrane electrode assembly in the longitudinal direction, the membrane electrode assembly can be folded in the lateral direction so that the anode catalyst layers are The cathode catalyst layers adjacent to the anode catalyst layer in the longitudinal direction face each other. The membrane electrode assembly folded in the above manner has formed therein a plurality of anode catalyst layers having surfaces in the same direction and a plurality of cathode catalyst layers having surfaces in the same direction opposite to the direction of the anode catalyst layer.

The membrane electrode assembly according to the seventh to ninth aspects may be folded in the lateral direction such that the anode catalyst layer and the cathode catalyst layer adjacent to the anode catalyst layer in the longitudinal direction face each other.

The membrane electrode assembly according to the above aspect has a structure in which a plurality of anode catalyst layers having surfaces in the same direction and a plurality of cathode catalyst layers having surfaces in the same direction opposite to that of the anode catalyst layers are formed therein. Therefore, by arranging the diffusion layer and the separator in the folded portion of the membrane electrode assembly, the fuel cell can be easily manufactured without poor assembly of the membrane electrode assembly generally present in the related art.

A fuel cell according to a tenth aspect of the present invention includes the membrane electrode assembly according to the ninth aspect, the fuel cell comprising: the membrane electrode assembly; a diffusion layer arranged on the anode catalyst layer of the membrane electrode assembly and the surface of the cathode catalyst layer; and a separator in which at least a fuel gas flow path on the anode catalyst layer side and an oxygen flow path on the cathode catalyst layer side are formed, and The separator is disposed between the anode catalyst layer and the cathode catalyst layer having the diffusion layers disposed opposite to each other. According to this aspect, a desired number of fuel cells can be obtained by cutting off the portion folded in the longitudinal direction of the membrane electrode assembly (the portion of the electrolyte membrane connecting individual fuel cells).

According to the present invention, it is possible to obtain a composite electrolyte membrane having stable dimensional accuracy in which the uniformity of electrolyte characteristics within the membrane is improved. Furthermore, it is possible to obtain a membrane electrode assembly in which the anode catalyst layer and the cathode catalyst layer are formed so as to form a composite type electrolyte membrane without displacement. Furthermore, a desired number of fuel cells free from pollutants can be easily obtained.

Description of drawings

The above and/or other objects, features and advantages of the present invention will become more apparent from the following description of preferred embodiments with reference to the accompanying drawings, in which like reference numerals are used for like elements, and wherein :

1 is a schematic diagram showing a method for manufacturing a composite electrolyte membrane according to a first embodiment of the present invention;

Figure 2 is a schematic diagram of a manufacturing facility for implementing the manufacturing method shown in Figure 1;

3 is a schematic diagram showing a method for manufacturing a composite electrolyte membrane according to a second embodiment of the present invention;

4 is a schematic diagram showing a method for manufacturing a composite electrolyte membrane according to a third embodiment of the present invention;

5 is a schematic diagram showing a method for manufacturing a composite electrolyte membrane according to a fourth embodiment of the present invention;

6 is a schematic diagram of a manufacturing facility for implementing the manufacturing method shown in FIG. 5;

7 is a schematic diagram showing a method for manufacturing a composite electrolyte membrane according to a fifth embodiment of the present invention;

8 is a schematic diagram showing a method for manufacturing a composite electrolyte membrane according to a sixth embodiment of the present invention;

9 is a schematic diagram illustrating a method for manufacturing a membrane electrode assembly according to an embodiment of the present invention;

Figure 10 shows a second fold of the membrane electrode assembly shown in Figure 9;

Figure 11 shows a method for fabricating a fuel cell from the membrane electrode assembly shown in Figure 10;

FIG. 12 shows a method for manufacturing a fuel cell having a desired number of unit cells from the fuel cell manufactured by the method shown in FIG. 11;

13A shows a method for manufacturing a composite electrolyte membrane by a casting film forming method in a method for manufacturing a composite electrolyte membrane according to the related art;

13B shows a method for forming a catalyst layer on a composite electrolyte membrane through a transfer process in a method for manufacturing a composite electrolyte membrane according to the related art; and

Fig. 14 is a schematic diagram showing an example of a solid polymer type fuel cell (single cell) according to the related art.

Detailed ways

Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

1 is a schematic diagram showing a method for manufacturing a composite electrolyte membrane (electrolyte membrane) of a first embodiment, and FIG. 2 is a schematic diagram of a manufacturing facility for implementing the manufacturing method shown in FIG. 1 .

As shown in Figures 1 and 2, at first, prepare a sheet (electrolyte sheet) 11 made of a strip-shaped electrolyte and a strip-shaped reinforcing sheet 12 made of polytetrafluoroethylene (PTFE) which is a porous polymer material, And implement the lamination process. More specifically, in the lamination process, the electrolyte sheet 11 and the reinforcement sheet 12 are heated and laminated to produce a laminate 10A in which the electrolyte sheet serves as the electrolyte layer 11a and the reinforcement sheet 12 serves as the reinforcement layer 12a.

The method for laminating the two sheets can be carried out by gluing or dipping. More specifically, as shown in FIG. 2, for example, by heating and pressing the electrolyte sheet 11 and the reinforcement sheet 12 together between a pair of rollers 31a, 31b, a part of the electrolyte sheet can be impregnated into the reinforcement sheet. 12 in one surface. The temperature of the heating performed in this process is preferably in the range of 100 to 280°C. As a result, the electrolyte sheet 11 and the reinforcement sheet 12 can be integrated. Instead of the electrolyte sheet 11, molten electrolyte may be used.

Then, the laminated body 10A produced in the laminating step is folded. More specifically, the laminated body 10A is folded at the central portion along the center line L of the laminated body 10A so that a part of the front surface (reinforcement layer surface) of the laminated body 10A on the reinforcing layer 12a side is positioned on the other part of the front surface, Thus, a laminated body 10B was manufactured.

More specifically, as shown in FIG. 2 , the laminate can be folded at the center in the transverse direction of the laminated body 10A by rollers 32 a, 32 b having V-shaped protrusions and recesses and rotating in the transport direction (MD direction) of the laminated body 10A. Body 10A. Then, the laminated body 10A deformed into a V-shape by the rollers 33a, 33b is further folded such that a part of the reinforcing layer 12a of the laminated body 10A is positioned on the other part, and the reinforcing layer 12a is formed by heating and pressing with the rollers 33a, 33b. surface bonding. The temperature for heating the laminated body 10A in this process is preferably in the range of 100 to 280°C.

Then, the laminated body 10B produced in the folding process is turned by 90° by the rollers 34a, 34b, and the laminated body 10B is dipped. More specifically, the laminated body 10B is heated and pressurized until the electrolyte is melted, and the electrolyte is impregnated into the reinforcement layer 12a to manufacture the laminated body 10C.

More specifically, as shown in FIG. 2, the electrolyte of the electrolyte layer 11a on the surface of the laminated body 10B may be impregnated into the pores of the porous reinforcing layer 12a, and heating and pressing rollers rotating in the conveyance direction of the laminated body 10B may be used. 35a, 35b obtain the reinforcing layer 12b impregnated with electrolyte. The temperature for heating the laminated body 10B in this process is preferably in the range of 200 to 280°C.

The laminate 10C produced in the immersion step can be hydrolyzed, the ion exchange function can be imparted to the laminate 10C, and the composite electrolyte membrane 100A can be obtained. As shown in FIG. 2 , after the hydrolysis step, the composite electrolyte membrane 100A can be dried, and the plate-shaped composite electrolyte membrane 100A can be wound by a winding device (not shown).

The composite electrolyte membrane 100A thus obtained is manufactured from only two sheets: the electrolyte sheet 11 and the reinforcing sheet 12 . Therefore, the sheets can be easily arranged, and the quality of the electrolyte membrane can be stabilized. Furthermore, the laminated body 10A may be folded and the electrolyte of one electrolyte sheet 11 may be impregnated. As a result, a uniform electrolyte constituting the same electrolyte sheet 11 is arranged on both surfaces of the composite electrolyte membrane 100A, and the thickness of the electrolyte membrane is also stabilized. In this way, the uniformity of the electrolyte characteristics in the electrolyte membrane can be improved, a high-precision electrolyte membrane can be obtained, and the performance of the fuel cell can be stabilized.

Further, the folding process is performed so that a part of the surface on the reinforcing layer 12a side (reinforcement layer surface) is positioned on the other part, and the surface on the electrolyte layer 11a side (electrolyte surface) becomes the front surface of the laminated body 10B. Therefore, in the impregnation process, the electrolyte layer 11a is formed in the surface layer in the thickness direction, and the position of the reinforcement layer 12a is stabilized. As a result, in the fuel cell equipped with the electrolyte membrane 100A, dispersion of water movement within the surface of the electrolyte membrane 100A during power generation is suppressed by the electrolyte layer 11 a of the surface layer. In addition, adhesion of the electrolyte membrane 100A to a catalyst layer (not shown in the figure) can be improved, and fuel cell performance can be stabilized.

Furthermore, in the case of manufacturing the composite electrolyte membrane 100A by the manufacturing method shown in FIG. 2 , the lamination process can be performed only by joining two members, and the operations from the lamination process to the hydrolysis process can be implemented as a continuous procedure. Therefore, the process can be simplified, quality control can be facilitated, and productivity can be improved.

FIG. 3 shows a second embodiment of the method for manufacturing a composite electrolyte membrane according to the present invention. This embodiment differs from the first embodiment shown in FIG. 1 in that catalyst layers 13a, 13b are provided. FIG. 3 shows the process before forming the catalyst layer of the membrane electrode assembly (MEA) 50A. The manufacturing method of the second embodiment includes the above-mentioned lamination process, folding process, dipping process, and hydrolysis process, and the same reference numerals are used for these processes and detailed description thereof will be omitted.

As shown in FIG. 3 , in the lamination step, the electrolyte sheet 11 and the reinforcement sheet 12 are bonded and laminated to manufacture a laminate 10A composed of the electrolyte layer 11 a and the reinforcement layer 12 a. Then, after laminate 10A has been formed, anode catalyst layer 13a and cathode catalyst layer 13b are arranged on the surface of electrolyte layer 11a, and laminate 10D on which catalyst layers 13a, 13b are formed is manufactured.

More specifically, in the catalyst disposing process, the catalyst layers 13a, 13b may be disposed by blowing the catalyst with an injector, or the catalyst layer may be disposed on the substrate sheet, and then may be heated and pressurized by using a tool or a coating die. The catalyst layer is transferred onto the electrolyte layer. The advantage of using the catalyst layer ionomer as the precursor polymer is that it can prevent the thermal degradation of the ionomer in the subsequent impregnation process.

Then, in the folding process, the laminated body 10D is folded such that the anode catalyst layer 13a is arranged on one surface of the laminated body 10E, and the cathode catalyst layer 13b is arranged on the other surface of the laminated body 10E. In the subsequent impregnation step, the electrolyte is impregnated into the reinforcement layer 12 a to manufacture the laminated body 10F. In the hydrolysis process, an ion exchange function is imparted to the electrolyte of the laminate 10F, and a membrane electrode assembly 50A including the composite electrolyte membrane 100B can be obtained.

By the method for manufacturing the composite electrolyte membrane 100B and the membrane electrode assembly 50A described above, the anode catalyst layer 13a and the cathode catalyst layer 13b are formed in the same surface of the laminated body 10A obtained in the lamination process on which the electrolyte layer 11a has been formed. . Therefore, the catalyst layers 13a, 13b can be precisely positioned. As a result, displacement of the anode catalyst layer 13 a and the cathode catalyst layer 13 b can be suppressed while the accuracy of the folding position of the laminate 10D in the folding process can be maintained.

By employing the membrane electrode assembly 50A including the electrolyte membrane 100B manufactured in the above manner in a fuel cell, it is possible to prevent poor assembly when the membrane is assembled into a unit cell of the fuel cell, and to suppress dispersion of fuel cell performance during power generation. In particular, since the electrolyte layer 11a of the surface layer is formed with good stability, the adhesion of the electrolyte layer 11a to the catalyst layers 13a, 13b can be improved.

FIG. 4 shows a third embodiment of the method for manufacturing a composite electrolyte membrane according to the present invention. The manufacturing method of the third embodiment differs from that of the first embodiment shown in FIG. 1 in that the folding direction is different in the folding process. The manufacturing method of the third embodiment includes the above-mentioned lamination process, dipping process, and hydrolysis process, and the same reference numerals are used for these processes and detailed description thereof will be omitted.

As shown in FIG. 4 , in the lamination process, the electrolyte sheet 11 and the reinforcement sheet 12 are bonded and laminated to manufacture a laminate 10A composed of the electrolyte layer 11 a and the reinforcement layer 12 a. Then, the folding process is performed on the laminated body 10A produced in the laminating process. More specifically, the laminated body 10A is folded at the central portion along the center line L of the laminated body 10A so that a part of the front surface (electrolyte layer surface) of the laminated body 10A on the side of the electrolyte layer 11a is positioned on the other part of the front surface. , thereby manufacturing a laminated body 10G.

Then, in the impregnation step, the reinforcement layer 12 a is impregnated with an electrolyte to manufacture a laminated body 10H. In the hydrolysis step, an ion exchange function is imparted to the electrolyte of the laminate 10H, and a composite electrolyte membrane 100C can be obtained.

With the method for manufacturing composite electrolyte membrane 100C described above, laminated body 10A is folded in the following process so that one part of the surface of electrolyte layer 11a lies on the other, and reinforcement layer 12a becomes the surface of the electrolyte membrane. Accordingly, the electrolyte layer 11b is formed at the center in the thickness direction of the composite electrolyte membrane 100C, and the reinforcement layer 12b impregnated with electrolyte may be arranged in a surface layer portion close to the surface in the thickness direction of the electrolyte membrane. As a result, the creep performance of the electrolyte membrane 100C during operation of the fuel cell can be improved.

FIG. 5 shows a fourth embodiment of the method for manufacturing a composite electrolyte membrane according to the present invention. FIG. 6 is a schematic diagram of a manufacturing facility for implementing the manufacturing method shown in FIG. 5 . The manufacturing method of the fourth embodiment is different from that of the first embodiment in that the water-retaining material is disposed after the lamination process. The manufacturing method of the fourth embodiment includes the above-mentioned lamination process, dipping process, and hydrolysis process, and the same reference numerals are used for these processes and detailed description thereof will be omitted.

As shown in FIG. 5 , in the lamination step, the electrolyte sheet 11 and the reinforcement sheet 12 are bonded and laminated to manufacture a laminate 10A composed of the electrolyte layer 11 a and the reinforcement layer 12 a. In the subsequent water-retaining material arrangement process, the water-retaining material 14 is arranged on the surface of the reinforcement layer 12a after the laminated body 10A has been formed. More specifically, as shown in FIG. 6, the water-retaining material 14 is coated on the surface of the reinforcement layer 12a by a coating process such as pattern coating or spraying or by sputtering so that the water-retaining material is uniformly disposed thereon. In this way, since the water-retaining material is sandwiched between reinforcing layers in a folding process described later, it is preferable that the water-retaining material is firmly adhered to prevent it from coming off during folding. When a finely powdered material is used as the water-retaining material, since it is sandwiched, it is preferable that the particle size of the water-retaining material is larger than the diameter of pores formed in the reinforcement sheet during folding as described above.

Then, in the folding process, the water retaining material 14 is sandwiched between the reinforcing layers 12a so that one part of the surface on the reinforcing layer side is positioned on the other, the laminated body 10I is folded, and a laminated body 10J is manufactured. In the immersion step, the electrolyte of the electrolyte layer 11a is impregnated into the water-retaining material 14 and the reinforcement layer 12a to manufacture a laminated body 10K. In the hydrolysis step, the electrolyte of the laminate 10K is hydrolyzed to impart an ion exchange function thereto, and a composite electrolyte membrane 100D is obtained.

In this way, as shown in FIG. 5 , a composite electrolyte membrane 100D including at least an additive layer 14b in which a water-retaining material 14 is added to the electrolyte as an additive, a reinforcement layer formed to sandwich the additive layer 14b and impregnated with electrolyte can be obtained. 12b and the electrolyte layer 11a formed on the surface of the reinforcing layer 12b, the foregoing layers being stacked in the thickness direction of the membrane.

In the composite electrolyte membrane 100D manufactured in the above manner, the water retaining material 14 is sandwiched as an additive during folding, whereby the water retaining material can be fixed at the center in the thickness direction of the electrolyte membrane 100D. As a result, the water retaining material 14 can be prevented from moving due to water movement, and flow loss during fuel cell power generation can be suppressed. As a result, stable proton conductivity can be ensured.

FIG. 7 shows a fifth embodiment of the method for manufacturing a composite electrolyte membrane according to the present invention. The manufacturing method of the fifth embodiment differs from the fourth embodiment in that a catalyst layer is present in the lamination process. The manufacturing method of the fifth embodiment includes the above-mentioned dipping process, folding process, and hydrolysis process, and these processes use the same reference numerals and their detailed descriptions are omitted.

As shown in FIG. 7 , in the lamination process, the electrolyte sheet 11 and the reinforcement sheet 12 are bonded and laminated. Simultaneously, the anode catalyst layer 13a and the cathode catalyst layer 13b arranged on the backing sheet 81 are arranged from the surface on the other side of the electrolyte sheet 11 to manufacture a laminated body 10L.

Then, the membrane electrode assembly 50B including the composite electrolyte membrane 100E can be obtained through a water-retaining material arrangement process, a folding process, an impregnation process, and a hydrolysis process. In this case, the substrate sheet 81 is removed from the laminated body 10K after the impregnation process, the electrolyte of the laminated body 10K is given an ion exchange function after the hydrolysis process, and a membrane electrode including the composite electrolyte membrane 100E can be obtained Assembly 50B.

In this way, similar to the second embodiment, displacement of the anode catalyst layer 13a and the cathode catalyst layer 13b can be suppressed, poor assembly of unit cells of the fuel cell can be prevented, and dispersion of fuel cell performance during power generation can be suppressed. In the composite type electrolyte membrane 100E manufactured in the above manner, the water retaining material is fixed at the center in the thickness direction of the electrolyte membrane 100E. As a result, the water retaining material 14 can be prevented from moving due to water movement, and flow loss during fuel cell power generation can be suppressed. As a result, stable proton conductivity can be ensured.

FIG. 8 shows a sixth embodiment of the method for manufacturing a composite electrolyte membrane according to the present invention. The manufacturing method of the sixth embodiment differs from the fourth embodiment in that a water-retaining material is placed before the lamination process. The manufacturing method of the sixth embodiment includes the above-mentioned dipping process, folding process, and hydrolysis process, and these processes use the same reference numerals and their detailed descriptions are omitted.

As shown in FIG. 8 , in the lamination process, first, the water-retaining material 14 is arranged. The configuration method is the same as the above embodiment. Then, in the lamination process, the electrolyte sheet 11 and the reinforcement sheet 12 are arranged such that the water retaining material 14 is arranged between the electrolyte sheet 11 and the reinforcement sheet 12 . Since the bonding is performed by impregnating the electrolyte of the electrolyte sheet 11 from one side of the reinforcing sheet 12, a water-retaining material 14 is formed between the electrolyte layer 11a and the reinforcing layer 12a in the laminated body 10P after bonding. The additive layer 14b is added to the electrolyte. Then, the composite electrolyte membrane 100F is obtained through a folding process, an impregnation process, and a hydrolysis process.

In this way, as shown in FIG. 8, a composite electrolyte membrane 100F can be obtained, which includes at least a first electrolytic layer 11a as an electrolyte layer, wherein a water-retaining material is added to the electrolyte as an additive and sandwiches the first electrolyte layer 11a. Layer 14b, reinforcement layer 12b formed to sandwich additive layer 14b and impregnated with electrolyte, and second electrolyte layer 11b formed on the surface of reinforcement layer 12b are stacked in the thickness direction of the membrane.

In composite electrolyte membrane 100F obtained in the above manner, laminated body 10A is folded such that one part of the surface of electrolyte layer 11a lies on the other, and reinforcement layer 12a becomes the surface of the electrolyte membrane. Therefore, the electrolyte layer 11a is formed at the center in the thickness direction of the composite type electrolyte membrane 100F, the reinforcement layer 12b impregnated with electrolyte is arranged in the surface layer portion close to the surface in the thickness direction of the electrolyte membrane, and the additional layer may be arranged thereon. nearby. As a result, not only the creep performance of the electrolyte membrane 100F during operation of the fuel cell can be improved, but also the water retention capacity of the electrolyte membrane 100F can be further improved.

FIG. 9 is a schematic view showing a method for manufacturing a membrane electrode assembly according to an embodiment of the present invention, which is used to explain a second folding process applied to the membrane electrode assembly shown in FIG. 9 . As shown in FIG. 9 , a sheet (electrolyte sheet) 11 made of a belt-shaped electrolyte and a belt-shaped reinforcing sheet 12 made of polytetrafluoroethylene (PTFE), which is a porous polymer material, are prepared. Then, in the lamination process, the electrolyte sheet 11 and the reinforcing sheet 12 are heated, pressurized, and laminated, and a laminated body 10A is manufactured in which the electrolyte sheet is used as the electrolyte layer 11a and the reinforcing sheet 12 is used as the reinforcing sheet. Layer 12a.

Then, anode catalyst layer 13a and cathode catalyst layer 13b are disposed on the surface of electrolyte layer 11a after laminate 10A has been formed, and laminate 10D having catalyst layers 13a, 13b formed thereon is produced.

More specifically, in the catalyst disposition process, two rows of anode catalyst layer 13a and cathode catalyst layer 13b are formed on the surface of electrolyte layer 11a in the lateral direction S of laminate 10A after laminate 10A has been formed. In addition, the anode catalyst layers 13a and the cathode catalyst layers 13b are also arranged in the longitudinal direction (conveying direction) L such that a plurality of anode catalyst layers 13a and a plurality of cathode catalyst layers 13b are alternately formed (in other words, two rows of anode catalyst layers 13a formed diagonally to the cathode catalyst layer 13b), and these layers were fixed by applying pressure and heating at a temperature equal to or lower than 170°C.

In the same manner as in the second embodiment, the configuration of the catalyst layers 13a, 13b can be performed by blowing with an injector, by using a backing sheet, or by transferring using a tool or a coating die, and the configuration method is not affected by It is particularly limited as long as the plurality of catalyst layers 13a, 13b can be arranged on the desired surface of the electrolyte layer 11a in the above arrangement.

Then, in the folding process, the laminated body 10D is folded in the longitudinal direction L at the central portion of the laminated body 10D in the same manner as in the above-described several embodiments so that the anode catalyst layer 13a is arranged on one surface of the laminated body 10E, and The cathode catalyst layer 13b is arranged on the other surface of the laminate 10E (the anode catalyst layer 13a and the cathode catalyst layer 13b are arranged to sandwich the laminate 10E (composite electrolyte membrane) therebetween). Then, in the impregnation step, the electrolyte is impregnated into the reinforcement layer 12 a to manufacture the laminated body 10F. In the hydrolysis process, an ion exchange function is imparted to the electrolyte of the laminate 10F, and a membrane electrode assembly 50C including the composite electrolyte membrane 100B can be obtained.

Since the anode catalyst layer 13a and the cathode catalyst layer 13b are formed in the same surface (in which the electrolyte layer 11a of the laminate has been formed after the lamination process) in the lateral direction S, these catalyst layers 13a, 13b can be separated without displacement. Precisely configured to sandwich the composite electrolyte membrane 100B. As a result, the displacement of the mutual arrangement of the anode catalyst layer 13 a and the cathode catalyst layer 13 b can be suppressed while maintaining the accuracy of the folding position of the stacked body 10E in the folding process, and it is possible to prevent assembly defects in the following assembly of the fuel cell 1 . , and performance dispersion during power generation by the fuel cell 1 can be suppressed.

The membrane electrode assembly 50C is a belt-shaped membrane electrode assembly, and since a plurality of anode catalyst layers 13a and a plurality of cathode catalyst layers 13b are alternately formed on the surface of the membrane electrode assembly 50C in the longitudinal direction, it is possible to pass through the second folding process described below. Fuel cells are easily fabricated.

Then, the second folding is performed on the membrane electrode assembly 50C. More specifically, as shown in FIG. 10 , in the second folding process performed after the hydrolysis process, the membrane electrode assembly 50C is folded in the lateral direction S (along C1-C1, C2-C2, ... in the figure), such that The anode catalyst layer 13a and the cathode catalyst layer 13b adjacent to the anode catalyst layer 13a in the longitudinal direction L face each other.

Such folding can be performed, for example, by preparing a folding tool having a thickness such that a separator described below can be introduced, pressing the tip of the folding tool in the transverse direction S, and folding, but the folding method is not particularly limited as long as the folding can be performed The catalyst layers 13 a , 13 b adjacent in the longitudinal direction L may face each other.

In the case where the second folding process is carried out in the above-mentioned manner, if the following separators and the like are arranged between these opposing catalyst layers 13a, 13b, it is possible to easily manufacture from one continuous membrane electrode assembly 50C without displacement. A single cell of the fuel cell in which the catalyst layers 13a, 13b are formed in place without stacking a plurality of membrane electrode assemblies.

Furthermore, since a plurality of anode catalyst layers 13a and a plurality of cathode catalyst layers 13b are alternately formed in the longitudinal direction L, and the cathode catalyst layers 13b are always formed in a layer adjacent to the anode catalyst layer 13a in the longitudinal direction L, the second fold The process forms a plurality of anode catalyst layers 13a having a surface in the same direction (a surface in contact with the diffusion layer 15), and forms a plurality of cathode catalyst layers having a surface in the same direction opposite to the aforementioned direction (a surface in contact with the diffusion layer 15). Layer 13b. As a result, an assembly error of the anode catalyst layer and the cathode catalyst layer of the membrane electrode assembly, which may occur when a plurality of membrane electrode assemblies are stacked in a usual method, can be prevented.

A method of manufacturing a fuel cell using the membrane electrode assembly manufactured in the above manner will be described below. FIG. 11 shows a method for manufacturing a fuel cell from the membrane electrode assembly 50C shown in FIG. 10 .

In this embodiment, the method for manufacturing a fuel cell includes disposing the diffusion layer 15 on the surfaces of the anode catalyst layer 13a and the cathode catalyst layer 13b of the membrane electrode assembly 50C after the second folding process, and then disposing the A step of disposing the separator 60 in which the fuel gas flow path 61 and the oxygen flow path 62 are formed between the anode catalyst layer 13 a and the cathode catalyst layer 13 b of the diffusion layer.

More specifically, the separator 60 in which the fuel gas flow path 61 and the oxygen flow path 62 are formed is prepared. Then, the diffusion layer 15 for being arranged on the surfaces of the anode catalyst layer 13 a and the cathode catalyst layer 13 b is arranged on both surfaces of the separator 60 . Then, members 63 capable of sealing and adhering the membrane electrode assembly 50C are attached to both ends of the separator 60 in the longitudinal direction.

Separator 60 with diffusion layer 15 and sealant 63 attached is inserted toward the folded portion of MEA 50C such that diffusion layer 15 is located on anode catalyst layer 13 a and cathode catalyst layer 13 b of MEA 50C. As a result, a laminated electrode is formed by sandwiching the diffusion layer 15 and the separator 60 on the upper surfaces of the opposing catalyst layers 13a, 13b of the membrane electrode assembly 50C, and subsequent heating and pressure in the thickness direction produce a stacked A fuel cell 1 having a plurality of unit cells.

By the above method, compared with the usual method of arranging separators between a plurality of membrane electrode assemblies, the number of operation steps can be reduced, and since separators can be arranged in a continuous manner after the second folding process, it is possible to Incorporation of pollutants in the process of forming the unit cells of the fuel cell 1 is suppressed.

FIG. 12 shows a method for manufacturing a fuel cell including a desired number of unit cells from the fuel cell manufactured by the manufacturing method shown in FIG. 11 . As shown in FIG. 12, in the fuel cell 1 manufactured by the manufacturing method shown in FIG. 11, the fuel cell composed of a plurality of unit cells is connected through an electrolyte membrane in an insulated state. Therefore, as shown in FIG. 11, a fuel cell 1A, 1b composed of a necessary number of unit cells can be obtained in an assembled state (from several unit cells to hundreds of unit cells) by cutting off the electrolyte membrane at the connecting portion, while There are no assembly errors in the mutual arrangement of the orientation (orientation of the anode/cathode surfaces) that occur during cell stacking.

The embodiments of the composite electrolyte membrane, the membrane electrode assembly and the fuel cell according to the present invention and the method for manufacturing them are described above, however, the present invention is not limited to these embodiments, but can be used without departing from the appended Various design modifications are made without compromising the essence of the present invention described in the claims.

For example, in the fourth to sixth embodiments, a water-retaining material is used as an additive, but a radical inhibitor composed of an oxide of a transition metal such as cerium may also be used to suppress superfluous particles generated as a by-product during power generation of a fuel cell. Hydrogen oxide decomposes into water and oxygen and inhibits the generation of hydroxyl radicals.

Furthermore, in the composite type electrolyte membranes produced in the first to sixth embodiments, the folded ends serving as the folding margin formed in the folding process can be cut off with a cutter or the like.

In the second to fifth embodiments, the catalyst layer is additionally arranged, but obviously, a fuel cell can be obtained by additionally arranging the diffusion layer and the separator shown in FIG. 14 on the catalyst layer.

In addition, in the embodiment shown in FIG. 11, when arranging the diffusion layer and the separator, the separator having the diffusion layer formed on its surface is arranged in the membrane electrode assembly by being inserted into the folded portion of the membrane electrode assembly. , but the method is not limited, and the diffusion layer and the separator can also be arranged separately, as long as the diffusion layer and the separator can be arranged in the membrane electrode assembly and a fuel cell can be manufactured. In addition, in this embodiment, the catalyst layer is disposed after the stacking process, but the anode catalyst layer and the cathode catalyst layer may be further disposed on the diffusion layer disposed on the separator without disposing the catalyst layer on the electrolyte membrane, It is only necessary that the anode catalyst layer and the cathode catalyst layer can be precisely arranged.

In addition, in the embodiments shown in FIGS. 9 to 12, additives such as water retention agents and free radical inhibitors are not configured in the composite electrolyte membrane, but for the fourth to fourth shown in FIGS. 5, 7 and 8 In the method described in the sixth embodiment, additives such as water retaining agent and free radical inhibitor can be configured in the composite electrolyte membrane.

While the invention has been described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the exemplary embodiments or configurations. On the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the exemplary embodiments are shown in various combinations and configurations that are illustrative, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the invention. Inside.

Claims (12)

1. A method for manufacturing a membrane electrode assembly, comprising a method for manufacturing a composite electrolyte membrane, the method for manufacturing a composite electrolyte membrane comprising: A lamination process for obtaining a laminated body by laminating and integrating an electrolyte sheet (11) comprising an electrolyte as an electrolyte layer (11a) and a reinforcing sheet (12) comprising a porous polymer material as a reinforcing layer (12a); a first folding process of folding said laminate obtained by said laminating process such that a part of a surface of said laminate is located on another part of the surface; an impregnation process of impregnating the electrolyte of the folded laminated body into the reinforcing layer (12a); and a hydrolysis step of hydrolyzing the electrolyte impregnated in the laminate; in In the first folding process, folding the laminated body such that a part of the surface of the laminated body on the reinforcing layer (12a) side is positioned on another part of the surface; In the lamination step, a belt-shaped laminate is formed, and after the laminate has been formed, an anode catalyst layer (13a) and a cathode catalyst layer (13b) are disposed on the surface of the electrolyte layer (11a) such that The anode catalyst layer (13a) and the cathode catalyst layer (13b) are formed along the lateral direction of the stack; In the first folding process, the laminate is folded in the longitudinal direction so that the anode catalyst layer (13a) is arranged on one surface of the laminate, and the cathode catalyst layer (13b) is arranged on on the other surface of the laminate; In the stacking step, the anode catalyst layer (13a) and the cathode catalyst layer (13b) are arranged such that a plurality of the anode catalyst layers (13a) and a plurality of the cathode catalyst layers (13b) are along said longitudinal directions alternate; and The method for manufacturing a membrane electrode assembly further includes folding the stacked body in the transverse direction after the hydrolysis process so that the anode catalyst layer (13a) is adjacent to the anode in the longitudinal direction. The second folding process of said cathode catalyst layers (13b) of catalyst layers (13a) facing each other. 2. The method for manufacturing a membrane electrode assembly according to claim 1, wherein, in the lamination process, formed by heating and laminating the electrolyte sheet (11) and the reinforcing sheet (12) the laminate. 3. The method for manufacturing a membrane electrode assembly according to claim 1, wherein, in the impregnation process, the folded laminate is heated until the electrolyte is dissolved, and the electrolyte is impregnated into the In the reinforcement layer (12a). 4. The method for manufacturing a membrane electrode assembly according to claim 2, wherein, in the impregnation process, the folded laminate is heated until the electrolyte is dissolved, and the electrolyte is impregnated into the In the reinforcement layer (12a). 5. The method for manufacturing a membrane electrode assembly according to claim 1, wherein, in the stacking process, after the stacked body has been formed, an overcoat is disposed on the surface of the reinforcing layer (12a). At least one of a free radical inhibitor that decomposes hydrogen oxide into water and oxygen and suppresses generation of hydroxyl radicals, and a water-retaining material (14). 6. The method for manufacturing a membrane electrode assembly according to any one of claims 1 to 4, wherein, in the lamination process, the electrolyte sheet (11) and the reinforcing sheet (12 ) and at least one of a free radical inhibitor and a water-retaining material (14) that decomposes hydrogen peroxide into water and oxygen and inhibits the generation of hydroxyl radicals is arranged. 7. A method for manufacturing a fuel cell, comprising the method for manufacturing a membrane electrode assembly according to claim 1, characterized in that it also includes a diffusion layer and separator configuration process, the diffusion layer and separator configuration process After the second folding process, disposing a diffusion layer (15) on the surface of the anode catalyst layer (13a) and the surface of the cathode catalyst layer (13b) of the membrane electrode assembly, and A separator (60) is arranged between the anode catalyst layer (13a) and the cathode catalyst layer (13b) of the configured diffusion layer (15), and a fuel gas flow path is formed in the separator (60). (61) and an oxygen flow path (62), so that the fuel gas flow path (61) is located on the anode catalyst layer (13a) side, and the oxygen flow path (62) is located on the cathode catalyst layer (13b) side. 8. A membrane electrode assembly, comprising at least a pair of anode catalyst layer (13a) and cathode catalyst layer (13b), said anode catalyst layer and cathode catalyst layer are configured on both surfaces of the composite electrolyte membrane, so that the The composite electrolyte membrane is sandwiched in the middle, and the composite electrolyte membrane has at least an electrolyte layer (11a) and a reinforcement layer (12a), the electrolyte layer includes electrolyte, and the porous polymer material is impregnated with the electrolyte, The membrane electrode assembly is characterized in that The composite electrolyte membrane includes: An added layer (14b) in which at least one of a radical inhibitor that decomposes hydrogen peroxide into water and oxygen and suppresses generation of hydroxyl radicals and a water-retaining material (14) is added to the electrolyte ; said reinforcing layer (12a) formed to sandwich said added layer (14b); and said electrolyte layer (11a) formed on the surface of each said reinforcement layer (12a); and wherein: the membrane electrode assembly is a strip-shaped membrane electrode assembly, and the anode catalyst layers (13a) and the cathode catalyst layers (13b) are alternately formed on the surface of the membrane electrode assembly in the longitudinal direction, and Wherein the membrane electrode assembly is folded in the transverse direction such that the anode catalyst layer (13a) and the cathode catalyst layer (13b) adjacent to the anode catalyst layer (13a) in the longitudinal direction face each other. 9. A fuel cell comprising the membrane electrode assembly according to claim 8, characterized in that it comprises: the membrane electrode assembly; a diffusion layer (15) disposed on the surface of the anode catalyst layer (13a) and the surface of the cathode catalyst layer (13b) of the membrane electrode assembly; and A separator (60) in which at least a fuel gas flow path (61) on the side of the anode catalyst layer (13a) and an oxygen flow path on the side of the cathode catalyst layer (13b) are formed (62), and the separator (60) is disposed between the anode catalyst layer (13a) and the cathode catalyst layer (13b) having the diffusion layer (15) disposed opposite to each other. 10. A membrane electrode assembly, comprising at least a pair of anode catalyst layer (13a) and cathode catalyst layer (13b), said anode catalyst layer and cathode catalyst layer are configured on both surfaces of the composite electrolyte membrane, so that the The composite electrolyte membrane is sandwiched in the middle, the composite electrolyte membrane has at least an electrolyte layer and a reinforcement layer (12a, 12b), the electrolyte layer includes an electrolyte, and the porous polymer material is impregnated with the electrolyte in the reinforcement layer , The membrane electrode assembly is characterized in that The composite electrolyte membrane includes: A first electrolyte layer (11a) as said electrolyte layer; Formed as an additive layer (14b) sandwiching the first electrolyte layer (11a), in the additive layer, a radical inhibitor that decomposes hydrogen peroxide into water and oxygen and suppresses generation of hydroxyl radicals and at least one of water-retaining materials (14) is added to the electrolyte; said reinforcing layer (12a, 12b) formed on the surface of said added layer (14b); and a second electrolyte layer (11b) serving as said electrolyte layer and formed on the surface of said reinforcement layer (12a, 12b); and wherein: the membrane electrode assembly is a strip-shaped membrane electrode assembly, and the anode catalyst layers (13a) and the cathode catalyst layers (13b) are alternately formed on the surface of the membrane electrode assembly in the longitudinal direction, and Wherein the membrane electrode assembly is folded in the transverse direction such that the anode catalyst layer (13a) and the cathode catalyst layer (13b) adjacent to the anode catalyst layer (13a) in the longitudinal direction face each other. 11. A fuel cell comprising the membrane electrode assembly according to claim 10, characterized in that comprising: the membrane electrode assembly; a diffusion layer (15) disposed on the surface of the anode catalyst layer (13a) and the surface of the cathode catalyst layer (13b) of the membrane electrode assembly; and A separator (60) in which at least a fuel gas flow path (61) on the side of the anode catalyst layer (13a) and an oxygen flow path on the side of the cathode catalyst layer (13b) are formed (62), and the separator (60) is arranged between the anode catalyst layer (13a) and the cathode catalyst layer (13b) having the diffusion layer (15) arranged opposite to each other. 12. A membrane electrode assembly, at least having a pair of anode catalyst layer (13a) and cathode catalyst layer (13b), said anode catalyst layer and cathode catalyst layer are configured on both surfaces of the composite electrolyte membrane, so that the The anode catalyst layer (13a) and the cathode catalyst layer (13b) sandwich the composite electrolyte membrane, and in the composite electrolyte membrane, a reinforcing sheet (12) comprising a porous polymer material is impregnated with an electrolyte sheet (11) comprising electrolyte, The membrane electrode assembly is characterized in that the membrane electrode assembly is a strip-shaped membrane electrode assembly, and the anode catalyst layers (13a) and the cathode catalyst layers (13b) are alternately formed on the surface of the membrane electrode assembly in the longitudinal direction, and Wherein the membrane electrode assembly is folded in the transverse direction such that the anode catalyst layer (13a) and the cathode catalyst layer (13b) adjacent to the anode catalyst layer (13a) in the longitudinal direction face each other.

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