KR101715447B1 - Method for manufacturing membrane eletrode assembly, membrane eletrode assembly and fuel cell comprising the same - Google Patents

Abstract

The present application relates to an electrolyte membrane having a concave portion on the surface of an electrolyte membrane; And an electrode having a convex portion on a surface thereof, a method for producing the membrane electrode assembly, and a fuel cell including the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a membrane electrode assembly, a membrane electrode assembly, and a fuel cell including the membrane electrode assembly,

This application claims the benefit of the filing date of Korean Patent Application No. 10-2013-0068584 filed with the Korean Intellectual Property Office on June 14, 2013, the entire contents of which are incorporated herein by reference.

The present application relates to a method for producing a membrane electrode assembly, a membrane electrode assembly and a fuel cell including the same.

2. Description of the Related Art In recent years, due to rapid diffusion of portable electronic devices and wireless communication devices, much attention and research have been made on the development of a fuel cell as a portable power source battery, a fuel cell for a pollution-free vehicle, and a fuel cell for power generation as a clean energy source.

Fuel cells are energy conversion devices that convert the chemical energy of a fuel directly into electrical energy. That is, a fuel cell uses a fuel gas and an oxidizing agent and generates electricity using electrons generated during the oxidation / reduction reaction. As a result, the fuel cell has a high energy efficiency and an environment- Research and development.

The fuel cells include a polymer electrolyte membrane fuel cell (PEMFC), a direct methanol fuel cell (DMFC), a phosphoric acid fuel cell (PAFC), an alkaline fuel cell (Alkaline Fuel Cell) (AFC), Molten Carbonate Fuel Cell (MCFC), and Solid Oxide Fuel Cell (SOFC). Among them, polymer electrolyte fuel cells are attracting attention as portable power supplies, automobiles, and household power supplies due to their low operating temperatures, the elimination of leaking problems caused by the use of solid electrolytes, and quick driving. In addition, it is a high-output fuel cell having a higher current density than other types of fuel cells, and is operated at a temperature of less than 100 ° C, has a simple structure, has a fast start-up and response characteristic and excellent durability, Gas can be used as fuel. In addition, miniaturization can be achieved with a high output density, and research on a portable fuel cell continues.

In recent years, improvement in performance, life span, and cost reduction has been one of the factors that must be improved for the commercialization of polymer electrolyte fuel cells. The most influential components are membrane electrode assemblies (MEAs) )to be. The membrane electrode assembly has a structure in which an anode and a cathode are coated on both sides of an electrolyte membrane composed of a polymer material as a unit cell structure of a fuel cell. This membrane electrode assembly is composed of a cathode, an anode, and an electrolyte membrane, that is, an ion conductive electrolyte membrane, where electrochemical reaction of hydrogen and oxygen occurs. 1 showing the principle of electricity generation of a fuel cell, oxidation reaction of fuel occurs in the anode, hydrogen ions and electrons are generated, and hydrogen ions move to the cathode through the electrolyte membrane, and through the oxygen and the electrolyte membrane The transferred hydrogen ions and electrons react to form water. This reaction causes electrons to migrate to the external circuit.

Since the membrane electrode assembly of the related art has a flat membrane, the electrolyte membrane and the membrane electrode assembly have been manufactured. Therefore, the bonding performance between the electrolyte membrane and the electrode is not so large depending on the process, and the performance of the polymer electrolyte fuel cell is degraded or the life is shortened .

Accordingly, there has been a need to develop a membrane electrode assembly capable of overcoming the above problems.

Korean Patent Publication No. 10-2003-0076057

A problem to be solved by the present invention is to provide a membrane electrode assembly, a membrane electrode assembly, a membrane electrode assembly, and a membrane electrode assembly, which can improve the fuel cell performance and shorten the service life when the electrolyte membrane is manufactured using a flat film, A method for producing the same, and a fuel cell including the same.

According to an embodiment of the present invention, there is provided a method of manufacturing an electrolyte membrane, comprising: preparing an electrolyte membrane having a plurality of concave portions on a surface thereof by pressing at least a portion of one surface or both surfaces of the electrolyte membrane with a press having irregularities on the surface; Pressing at least a portion of the surface of the electrode surface in contact with the electrolyte membrane with a press having irregularities on the surface to manufacture an electrode having a plurality of convex portions on the surface having a shape engaging with the concave portion of the electrolyte membrane; And bonding the electrolyte membrane and the electrode so that the concave portion on the surface of the electrolyte membrane and the convex portion of the electrode surface are in mesh with each other.

One embodiment of the present application provides a membrane electrode assembly produced by the above method.

One embodiment of the present application relates to an electrolyte membrane comprising a plurality of recesses in at least a portion of surfaces of both surfaces of an electrolyte membrane; And an electrode disposed in contact with the electrolyte membrane and having a plurality of protrusions on a surface thereof, the protrusions being in engagement with the recesses of the electrolyte membrane.

One embodiment of the present application includes at least one membrane electrode assembly; And a separator plate provided between each of the membrane electrode assemblies.

One embodiment of the present application provides a fuel cell including the membrane electrode assembly.

Since the membrane electrode assembly according to one embodiment of the present application includes a plurality of recesses on the surface of the electrolyte membrane and a plurality of protrusions on the surface of the electrode to be bonded to each other, The surface area at the interface is increased and the ion conduction efficiency is increased. In addition, the bonding strength between the electrolyte membrane and the electrode is improved, thereby reducing the phenomenon that the electrolyte membrane and a part of the electrode are separated during long-term operation. Thus, the performance of the fuel cell can be improved and the lifetime can be extended. In addition, the bonding strength between the electrolyte membrane and the electrode is improved, thereby reducing the phenomenon that the electrolyte membrane and a part of the electrode are separated during long-term operation.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view for explaining an electricity generation principle of a fuel cell.
FIG. 2 illustrates a process of manufacturing a membrane electrode assembly by bonding an electrolyte membrane and an electrode according to an embodiment of the present application.
3 shows a process of manufacturing an electrolyte membrane according to an embodiment of the present application.
4 shows a process of manufacturing an electrode according to an embodiment of the present application.
5 schematically shows the structure of a membrane electrode assembly according to an embodiment of the present application.
FIG. 6 is a graph showing the movement path of hydrogen and oxygen and the movement path of protons in the membrane electrode assembly according to one embodiment of the present application.
FIG. 7 shows the movement paths of the proton according to Comparative Examples 1 and 2.
8 schematically shows the structure of a fuel cell according to one embodiment of the present application.

Brief Description of the Drawings The advantages and features of the present application, and how to accomplish them, will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. It will be understood, however, that this application is not limited to the embodiments disclosed herein but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, Is provided to fully convey the scope of the invention to those skilled in the art, and this application is only defined by the scope of the claims. The dimensions and relative sizes of the components shown in the figures may be exaggerated for clarity of description.

Unless defined otherwise, all terms, including technical and scientific terms used herein, may be used in a manner that is commonly understood by one of ordinary skill in the art to which this application belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

Hereinafter, the present application will be described in detail.

One embodiment of the present application is a method of manufacturing an electrolyte membrane, comprising the steps of: (S1) preparing an electrolyte membrane having a plurality of recesses on a surface thereof by pressing at least a portion of one surface or both surfaces of the electrolyte membrane into a surface with an uneven surface press; (S2) of producing an electrode having a plurality of convex portions having a shape in which at least a portion of the surface of the electrode surface in contact with the electrolyte membrane is in contact with the concave portion of the electrolyte membrane on the surface thereof, ); And (S3) joining an electrolyte membrane and an electrode so that the concave portion on the surface of the electrolyte membrane and the convex portion of the electrode surface are engaged with each other.

One embodiment of the present application provides a membrane electrode assembly produced by the above production method.

One embodiment of the present application includes an electrolyte membrane (110) having a plurality of recesses in at least a part of surfaces of both surfaces of an electrolyte membrane; And electrodes (210a, 210b) disposed in contact with the electrolyte membrane and having a plurality of protrusions on a surface thereof, the protrusions being in engagement with the recesses of the electrolyte membrane.

In this specification, at least a part of the surface means a part of the surface or an entire surface.

Conventionally, a casting method and the like were mainly used in the production of an electrolyte membrane. The casting method is a method in which a solution in which a solute is dissolved in a solvent is molded into a predetermined shape, and the solvent is evaporated to form a film. Generally, the casting drying process takes some time, and it is very difficult to manufacture uniform shapes of various shapes because the drying state of each part is different in making concave shape.

On the other hand, the pressing method according to one embodiment of the present application is a method of making protrusions on the surface of a roll press and making concave portions by pressing the protrusions on a film that has already been produced at high speed, There is a feature that a concave portion having a dimension can be formed. In the case of using the roll press, since the process substrate is inserted between the upper and lower rolls, the recesses are formed by pressing the protrusions formed on the surfaces of both rolls. Therefore, Is reduced. Further, since the position of the concave portion is related to the position of the protrusions of the upper and lower rolls, it is easy to control such as making a concave portion at the same position in the vertical direction or shifting the concave portion.

According to one embodiment of the present application, since the concave portion is formed by pressing the press projection, the shape of the projection should be such that the area of the projection adjacent to the roll is wider than the end of the projection. That is, the shape of the press protrusion should be such that the angle between the projection and the roll exceeds 90 degrees. When the concave portion is formed in the film, the convex shape makes the shape of the concave portion less than half a circle, and at this time, the surface area of the film is increased, and the proton conduction can be improved.

FIG. 2 illustrates a process of manufacturing a membrane electrode assembly by bonding an electrolyte membrane and an electrode according to an embodiment of the present application. FIG. 3 illustrates a process of manufacturing an electrolyte membrane according to an embodiment of the present application, and FIG. 4 illustrates a process of manufacturing an electrode according to an embodiment of the present application. 5 shows a membrane electrode assembly according to an embodiment of the present application.

2 to 5, reference numeral 10 denotes a base, reference numeral 12 denotes a substrate for a gas diffusion layer, reference numeral 20 denotes an electrolyte membrane resin composition, and reference numeral 22 denotes an electrode catalyst composition. Reference numeral 30 is a mold plan view, 40 is a protruding portion, 50 is a concave portion made in the electrolyte membrane, 102 is a coated electrolyte membrane, and 202 is a coated electrode. Reference numeral 110 denotes an electrolyte membrane including a concave portion. Reference numeral 210a denotes a cathode including a convex portion. Reference numeral 210b denotes an anode including a convex portion.

When the surface of the electrolyte membrane is free of bending and uniform, it is two-dimensionally bonded to the electrode. At this time, the ionic conductivity at the interface between the electrolyte membrane and the electrode depends only on the state of the ionomer contained in the electrode, and the bonding property may not be good depending on the process. Therefore, there is a problem that a part of the electrolyte membrane and the electrode may be separated during long-term operation.

In the case of a membrane electrode assembly including an electrode having a concave portion formed on the surface of the electrolyte membrane according to one embodiment of the present application and having a plurality of convex portions shaped to engage with the concave portion of the electrolyte membrane, And the ion conduction efficiency at the interface is increased. Thus, the performance of the fuel cell can be improved and the lifetime can be extended. In addition, the bonding strength between the electrolyte membrane and the electrode is improved, thereby reducing the phenomenon that the electrolyte membrane and a part of the electrode are separated during long-term operation.

In the membrane electrode assembly according to one embodiment of the present application, the electrolyte membrane and the electrode are three-dimensionally bonded to each other. At this time, since the contact area between the electrolyte membrane and the electrode, that is, the reaction area is greatly increased as compared with the membrane electrode assembly in which the electrode is two-dimensionally bonded to the electrolyte membrane in the conventional flat shape, the thickness of the electrolyte membrane is relatively decreased There are advantages to be able to. In addition, since the bonding between the electrolyte membrane and the electrode becomes strong, there is also an advantage of reducing the slip phenomenon occurring at the time of bonding.

In one embodiment of the present application, step (S1) of manufacturing the electrolyte membrane is as follows.

In one embodiment of the present application, the step (S1) of preparing the electrolyte membrane comprises: (Sa) forming a flat electrolyte membrane by applying an electrolyte membrane resin composition to a substrate; And a step (Sb) of forming a plurality of recesses by pressing at least a portion of one surface and / or both surfaces of the electrolyte membrane with a press having irregularities on the surface thereof.

In the step (Sa) of forming the flat electrolyte membrane, a method of applying the electrolyte membrane resin composition to the substrate includes printing, tape casting, spraying, rolling, doctor blade coating, die coating, Coating, or brushing, but the present invention is not limited thereto.

In one embodiment of the present application, the step (S1) of manufacturing the electrolyte membrane may further include the step (Sc) of removing the substrate from the electrolyte membrane before or after the step (Sb) of forming the recess .

According to an embodiment of the present application, the step of forming the electrolyte membrane (S1) includes a step of forming a recess (Sb) in which the concave portion is formed only on one side, And a step (Sd) of forming a plurality of recesses by pressing at least one portion of the surface with a press having irregularities on the surface thereof.

As one example, the membrane electrode assembly may be fabricated in the following order: a step (Sa) for forming a flat electrolyte membrane, a step (Sc) for removing a substrate from the electrolyte membrane, and a step (Sb) for forming a depression on both surfaces of the electrolyte membrane.

As another example, a step (Sa) of forming a flat electrolyte membrane, a step (Sc) of removing a substrate from the electrolyte membrane, a step (Sb) of forming a recess on one surface of the electrolyte membrane, And the step (Sd).

As another example, a step (Sa) of forming a flat electrolyte membrane, a step (Sb) of forming a depression on one side of the electrolyte membrane, a step (Sc) of removing the base material in the electrolyte membrane, a step of forming a depression on the other side of the electrolyte membrane And the step (Sd).

In one embodiment of the present application, the diameter of the concave portion provided in the electrolyte membrane may be more than 1 mm but not more than 50 mm, and more specifically, not less than 5 mm and not more than 10 mm. When the diameter of the concave portion provided in the electrolyte membrane is 1 mm or less, it may be difficult to mechanically match the convex portion of the electrode with the concave portion of the electrolyte membrane. When the diameter of the concave portion is larger than 1 mm, the density of the concave portion in the electrolyte membrane may be 16 / cm ² or less.

In one embodiment of the present application, the depth of the concave portion provided in the electrolyte membrane may be 1/10 or more and less than 1/2 of the electrolyte membrane thickness, specifically, 1/5 or more and 2/5 or less. When the depth of the concave portion provided in the electrolyte membrane is not less than 1/2 of the thickness of the electrolyte membrane, there is a possibility that a hydrogen crossover occurs if the concave portion of the upper portion and the concave portion of the lower portion are connected.

Also, in the case of the convex pattern, the effect of increasing the surface area may be obtained, but this may increase the resistance because the thickness increases the thickness of the electrolyte membrane. However, in the embodiment of the present application, by providing the concave portion, the thickness of the electrolyte membrane can be reduced along with the increase of the surface area of the electrolyte membrane, thereby reducing the resistance and increasing the characteristics.

At this time, the thickness of the electrolyte membrane may be 5 micrometers to 100 micrometers, specifically 5 micrometers to 50 micrometers, and more specifically 10 micrometers to 20 micrometers. If the electrolyte membrane thickness is less than 5 micrometers, it may be difficult to have a desired level of mechanical strength. If the electrolyte membrane thickness exceeds 100 micrometers, the hydrogen ion conductivity may be lowered, and preferably 5 to 100 micrometers.

In one embodiment of the present application, the resin used for the electrolyte membrane may be a polymer having hydrogen ion conductivity, and any of those conventionally known in the art may be used. The polymer having hydrogen ion conductivity may be a polymer having one or two or more cation-exchange groups selected from the group consisting of a sulfonic acid group, a phosphoric acid group, a carboxylic acid group, a phosphoric acid group, a phosphonic acid group, and derivatives thereof in the side chain.

Specifically, the perfluorosulfonic acid polymer, the hydrocarbon polymer, the aromatic sulfonic polymer, the aromatic ketone polymer, the polybenzimidazole polymer, the polystyrene polymer, the polyester polymer, the polyimide polymer, the polyvinylidene fluoride polymer A polymer, a polyether sulfone type polymer, a polyphenylene sulfide type polymer, a polyphenylene oxide type polymer, a polyphosphazene type polymer, a polyethylene naphthalate type polymer, a polyester type polymer, a doped polybenzimidazole type polymer, a polyether Ketone-based polymers, polyphenylquinoxaline-based polymers, and polysulfone-based polymers. The polymer may be a single copolymer, an alternating copolymer, a random copolymer, a block copolymer, a multi-block copolymer or a graft copolymer, but is not limited thereto.

Recently, a sulfonated polymer has been attracting attention as a material of a non-fluorinated polymer electrolyte membrane. Examples thereof include sulfonated polyarylene ether-based polymers, sulfonated polyether ketone-based polymers, sulfonated polyetheretherketone-based polymers, sulfonated polyamide-based polymers, sulfonated polyimide-based polymers, sulfonated polyphosphazene-based polymers , A sulfonated polystyrene-based polymer, and a radiation-polymerized sulfonated low density polyethylene-g-polystyrene-based polymer. The polymer may be a single copolymer, an alternating copolymer, a random copolymer, a block copolymer, a multi-block copolymer or a graft copolymer, but is not limited thereto.

In one embodiment of the present application, the type of the substrate 10 is not limited and, for example, paper, glass, resin, or the like can be used.

In one embodiment of the present application, the electrolyte membrane resin composition 20 may include a solvent.

The solvent is selected from the group consisting of N, N'-dimethylacetamide (DMAc), N-methyl pyrrolidone (NMP), dimethyl sulfoxide (DMSO) N, N-dimethylformamide (DMF) may be used.

In one embodiment of the present application, the step of manufacturing the electrode (S2) is as follows.

According to an embodiment of the present invention, the step of forming the electrode includes the steps of: (S2) forming a flat and convex catalyst layer by applying an electrode catalyst composition to a substrate; And a step (Sb ') of forming a plurality of convex portions by pressing at least a portion of the surface of one surface of the catalyst layer with a press having irregularities on the surface thereof.

In one embodiment of the present application, the depth of the convex portion provided on the electrode may be 1/10 or more and less than 1/2 of the electrode thickness, specifically, 1/5 or more and 2/5 or less.

In one embodiment of the present application, the membrane electrode assembly may have electrodes on both surfaces of the electrolyte membrane. The electrode may be an anode or a cathode. The anode, which is an electrode through which the anode fluid is supplied, is referred to as an oxidizing electrode or a fuel electrode. In the anode, fuel is supplied to oxidize hydrogen to generate hydrogen ions (H +) and electrons. The cathode, which is the electrode through which the cathode fluid is supplied, is called a reducing electrode, an oxygen electrode, or an air electrode. At the cathode, hydrogen ions and oxygen that have passed through the polymer electrolyte membrane are combined with each other to generate water by the reduction reaction of oxygen.

The membrane electrode assembly is a unitary unit in which an electrode and an electrolyte membrane are bonded.

In one embodiment of the present application, the electrode, specifically, the anode and the cathode may include a catalyst layer. And the catalyst layer may be disposed in contact with the electrolyte membrane in the membrane electrode assembly. More specifically, the catalyst layer may be disposed so as to contact the concave portion of the electrolyte membrane. The electrode, specifically, the anode and the cathode may further include a gas diffusion layer. The cathode and / or the anode may be an electrode having a catalyst layer formed on one or both surfaces of a gas diffusion layer (GDL).

In one embodiment of the present application, the convex portion may be formed on the surface of the catalyst layer of the electrode.

The membrane electrode assembly has an advantage that the mechanical strength of the polymer electrolyte membrane inside the fuel cell during operation is greatly improved and the durability is excellent. Also, the hydrogen ion conductivity is excellent.

The step (S2) of manufacturing the electrode may include a step (Sa ') of forming a flat and convex catalyst layer by applying an electrode catalyst composition to the substrate. The electrocatalyst composition may comprise, for example, a catalyst, a polymeric ionomer and a solvent to promote catalyst dispersion.

The catalyst may be a metal catalyst or a metal catalyst supported on a carbon-based support, and the electrode catalyst composition may further include a hydrogen-ion conductive polymer.

As the metal catalyst, platinum, a transition metal or a platinum-transition metal alloy may be used. Specific examples of the metal catalyst include platinum, ruthenium, osmium, platinum-ruthenium alloys, platinum-osmium alloys, platinum-palladium alloys, platinum- Platinum-rhodium alloy, but is not limited thereto.

Examples of the carbon-based support include graphite, carbon black, acetylene black, denka black, cacao black, activated carbon, mesoporous carbon, carbon nanotubes, carbon nanofibers, carbon nanofines, carbon nanorings, carbon nanowires, One or a mixture of two or more selected from the group consisting of fullerene (C60) and super P may be a preferable example.

The polymer ionomer serves to provide a path for ions generated by the reaction between the fuel and the catalyst, such as hydrogen or methanol, to move to the electrolyte membrane. The polymer ionomer may specifically be a sulfonated polymer such as a Nafion ionomer or a sulfonated polytrifluorostyrene.

The use ratio of the polymer ionomer may be 5 to 30 parts by weight based on 100 parts by weight of the catalyst used. When the polymer ionomer is used in an amount of less than 5 parts by weight, the ion transmission passage in the catalyst layer may not be properly formed, and migration of ions formed by the catalytic reaction may not be smooth. If the amount is more than 30 parts by weight, the ionomer tends to cover the catalyst layer, and the reaction between the catalyst and the fuel may become difficult.

As the solvent for promoting the catalyst dispersion, any one or a mixture of two or more selected from the group consisting of water, butanol, isopropanol (IPA), methanol, ethanol, n-propanol, n-butyl acetate and ethylene glycol Lt; / RTI > The same anode solvent and cathode solvent may be used.

The ratio of the solvent in the electrocatalyst composition may be 100 to 5,000 parts by weight based on 100 parts by weight of the catalyst used. If the amount of the solvent is less than 100 parts by weight, the viscosity of the catalyst composition becomes too high, so that the dispersibility of the catalyst particles during coating may be lowered and the formation of a uniform catalyst layer may be difficult. If the amount is more than 5,000 parts by weight, the viscosity of the catalyst composition becomes too low, and the thickness of the catalyst layer coated at one time may be thin, so that the coating may be repeated several times, resulting in a problem of poor productivity.

The electrode catalyst composition may be applied to the substrate of the gas diffusion layer by printing, tape casting, spraying, rolling, doctor blade coating, die coating, spin coating or brushing. However, the present invention is not limited thereto.

In the step (Sa ') of forming the flat and convex catalyst layer, the substrate may be a gas diffusion layer base material (12). The substrate 12 is not particularly limited as long as the substrate 12 is generally conductive and has a porosity of 80% or more. The substrate 12 may include a conductive substrate selected from the group consisting of carbon paper, carbon cloth, and carbon felt. The gas diffusion layer may further include a microporous layer formed on one surface of the conductive base material, and the microporous layer may include a carbon-based material and a fluororesin.

Examples of the carbon-based material include graphite, carbon black, acetylene black, denka black, cacao black, activated carbon, mesoporous carbon, carbon nanotube, carbon nanofiber, carbon nanohorn, carbon nano ring, Fullerene (C60), and super P may be used, but are not limited thereto.

Examples of the fluororesin contained in the microporous layer include polytetrafluoroethylene, polyvinylidene fluoride (PVdF), polyvinyl alcohol, cellulose acetate, copolymers of polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP ) And styrene-butadiene rubber (SBR) may be used, but are not limited thereto.

In one embodiment of the present application, the irregularities of the press used in the step of forming the electrode may have a complementary shape that can be engaged with the irregularities of the press used in the step of forming the electrolyte membrane.

In one embodiment of the present application, the cross-sectional shape of the convex portion provided in the concave portion or the electrode provided in the electrolyte membrane may be semicircular, triangular, square, or saw-tooth.

In one embodiment of the present application, the plurality of concave portions or the plurality of convex portions may form a regular pattern or an irregular pattern.

In one embodiment of the present application, when the plurality of concave portions or the plurality of convex portions form a regular pattern, the distance between the concave portions or the convex portions may be 0.5 times or more the diameter of the concave portions or the convex portions.

One embodiment of the present application includes at least one membrane electrode assembly; And a separator plate provided between each of the membrane electrode assemblies.

The separator plate prevents the membrane electrode assemblies from being electrically connected to each other, and contacts the cathode and the anode of the membrane electrode assembly to transfer the fuel and the oxidant supplied from the outside to the membrane electrode assembly. A channel channel may be formed inside the separator plate.

The stack for a fuel cell serves to generate electricity through an electrochemical reaction between a fuel and an oxidant.

One embodiment of the present application provides a fuel cell including the membrane electrode assembly.

In one embodiment of the present application, the fuel cell includes a fuel cell stack 300 including a separator plate provided between at least one membrane electrode assembly and a membrane electrode assembly; A fuel supply part (500) for supplying fuel to the stack; And an oxidant supply 400 for supplying an oxidant to the stack.

8 schematically shows the structure of a fuel cell according to one embodiment of the present application.

Referring to FIG. 8, the fuel cell of the present application comprises a fuel cell stack 300, a fuel supply unit 500, and an oxidant supply unit 400. The fuel cell of the present application includes a cathode and an anode positioned opposite to each other, and at least one membrane electrode assembly located between the anode and the cathode and including an electrolyte membrane for a fuel cell according to the present application, and at least one separator plate, At least one fuel cell stack (300) for generating electricity through an electrochemical reaction of an oxidizing agent; A fuel supply unit (500) for supplying fuel to the electricity generation unit; And an oxidant supply unit 400 for supplying the oxidant to the electricity generating unit.

The fuel supply unit 500 includes a fuel tank 510 for storing fuel and a pump 520 for supplying fuel stored in the fuel tank 510 to the electricity generating unit, . The fuel may be selected from the group consisting of methanol, ethanol, butanol, propanol, formic acid, aqueous hydrogen compound solution and hydrogen gas. More specifically, it may be a hydrogen gas.

The oxidant supply part 400 serves to supply an oxidant to the electricity generation part. The oxidizing agent may be oxygen or air, and oxygen or air may be injected into the pump 520 to be used.

Hereinafter, the contents of the present application will be described in detail by way of examples and comparative examples, but the scope of the present application is not limited thereto.

< Example >

< Example  1>

A hydrocarbon or fluorine-based ion conductive resin solution was applied to polyethylene terephthalate (PET) or an olefin-reinforced base with a doctor blade, and then the temperature was gradually raised to 80 ° C., followed by drying for about 4 hours to prepare a polymer electrolyte membrane.

The substrate was removed from the electrolyte membrane, and pressed on both surfaces of the electrolyte membrane using a press including the convex portions to prepare an electrolyte membrane having the recesses.

The electrode catalyst ink was coated on the substrate of the gas diffusion layer with a doctor blade in a loading amount of 0.4 mg / cm ² on the cathode and the anode, respectively, to form a flat anode and a cathode catalyst layer. An electrode having a convex portion was produced by pressing a surface of one side of the catalyst layer using a press including a convex portion.

The electrolyte membrane and the electrode were bonded to each other to prepare a membrane electrode assembly.

< Comparative Example  1>

A membrane electrode assembly was prepared by bonding a flat anode and a cathode electrode having no recesses to the electrolyte membrane prepared in Example 1.

< Comparative Example  2>

A planar anode having no convex portion and a cathode electrode were bonded to a flat electrolyte membrane having no concave portion to prepare a membrane electrode assembly.

6 is a graph showing the movement path of hydrogen and oxygen and the movement path of protons in the membrane electrode assembly of Example 1. Fig. In Fig. 6, reference numeral I denotes a movement path of protons, and reference numeral II denotes a movement path of hydrogen and oxygen.

Referring to FIG. 6, the proton generated in the anode by the catalytic reaction is rapidly conducted to the convex portion provided in the cathode, so that the reduction reaction occurs rapidly. In addition, reference numeral II shows that the surface area is widened so that the reaction between hydrogen and the catalyst and the reaction between oxygen and the catalyst are activated.

FIG. 7 shows the movement paths of the proton according to Comparative Examples 1 and 2.

7A shows a membrane electrode assembly manufactured by bonding an electrolyte membrane having a concave portion and a flat electrode to each other in Comparative Example 1. FIG. At this time, since the air is filled in the concave portion of the electrolyte membrane, there is a problem that protons generated in the anode by the catalytic reaction with hydrogen can not be conducted to the cathode.

FIG. 7B shows a membrane electrode assembly manufactured by bonding a flat electrolyte membrane and a flat electrode in Comparative Example 2. FIG. At this time, when the protons generated in the anode by the catalytic reaction with hydrogen are conducted to the cathode, there is a problem that the resistance due to the film thickness increases because the conduction length is long.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Having described specific portions of the present application in detail, those skilled in the art will appreciate that these specific embodiments are merely preferred embodiments and that the scope of the present application is not limited thereto. Accordingly, the actual scope of the present application will be defined by the appended claims and their equivalents.

10: substrate
12: gas diffusion layer substrate
20: electrolyte membrane resin composition
22: electrode catalyst composition
30: Mold plan view
40: protruding portion
50: concave portion formed in the electrolyte membrane
100: electrolyte membrane
102: Coated electrolyte membrane
110: electrolyte membrane having a concave portion
200: electrode
200a: cathode
200b: anode
202: Coated electrode
210: Electrode having a convex portion
210a: Cathode having a convex portion
210b: an anode having a convex portion
300: Stack for fuel cell
400: oxidant supplier
500: fuel supply unit
510: Fuel tank
520: pump

Claims (26)

Pressing at least a portion of one surface or both surfaces of the electrolyte membrane with a press with irregularities on the surface to produce an electrolyte membrane having a plurality of recesses on the surface;
Wherein at least a portion of the surface of the electrode surface in contact with the electrolyte membrane is compressed by a press with irregularities on the surface so that only a surface of the electrode in contact with the electrolyte membrane has a plurality of convex portions having a shape engaging with the concave portion of the electrolyte membrane Lt; / RTI &gt;electrode; And
Joining the electrolyte membrane and the electrode so that the concave portion on the surface of the electrolyte membrane and the convex portion of the electrode surface are engaged with each other
Lt; / RTI &gt;
Wherein the pressing by the press is performed by a roll press. The method according to claim 1, wherein the step of preparing the electrolyte membrane comprises:
Applying an electrolyte membrane resin composition to a substrate to form a flat electrolyte membrane; And
And pressing at least a portion of the surface of one surface of the electrolyte membrane with a press with irregularities on the surface to form a plurality of recesses. The method according to claim 2, wherein, before or after the step of forming the concave portion,
And removing the substrate from the electrolyte membrane. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; 3. The method of claim 2, wherein after forming the recess,
Further comprising the step of pressing at least a portion of the surface of the other surface of the electrolyte membrane with a press with irregularities on the surface to form a plurality of recesses. The method for manufacturing a membrane electrode assembly according to claim 1, wherein the diameter of the concave portion provided in the electrolyte membrane is 1 mm or more and 50 mm or less. The method for manufacturing a membrane-electrode assembly according to claim 5, wherein the density of the concave portion in the electrolyte membrane is 16 / cm ² or less. The method for manufacturing a membrane-electrode assembly according to claim 1, wherein the depth of the concave portion provided in the electrolyte membrane is 1/10 or more and less than 1/2 of the thickness of the electrolyte membrane. The method according to claim 1,
Applying an electrode catalyst composition to a substrate to form a catalyst layer; And
And pressing at least a portion of the surface of one surface of the catalyst layer with a press with irregularities on the surface to form a plurality of protrusions only on the surface of the catalyst layer in contact with the electrolyte membrane Gt; The method for manufacturing a membrane-electrode assembly according to claim 8, wherein the substrate is a substrate for a gas diffusion layer. The method for manufacturing a membrane-electrode assembly according to claim 1, wherein the electrode is an anode or a cathode. The method for manufacturing a membrane-electrode assembly according to claim 1, wherein the depth of the convex portion provided on the electrode is 1/10 or more and less than 1/2 of the thickness of the electrode. The process for producing a membrane electrode assembly according to claim 1, wherein the unevenness of the press used in the step of producing the electrode has a complementary shape that can be intertwined with the unevenness of the press used in the step of forming the electrolyte membrane . The method for manufacturing a membrane-electrode assembly according to claim 1, wherein the cross-sectional shape of the concave portion or the convex portion is semicircular, triangular, square or saw-tooth. The method for manufacturing a membrane-electrode assembly according to claim 1, wherein the plurality of concave portions or the plurality of convex portions forms a regular pattern or an irregular pattern. The manufacturing method of a membrane-electrode assembly according to claim 1, wherein, when the plurality of concave portions or the plurality of convex portions form a regular pattern, the distance between the concave portions or the convex portions is 0.5 times or more of the diameter of the concave portion or the convex portion . A membrane electrode assembly produced by the method of any one of claims 1 to 15. delete delete delete delete delete delete delete delete delete delete

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