KR20080045455A - Adhesive composition for fuel cell, fuel cell manufactured therefrom and method for preparing fuel cell using same - Google Patents

Abstract

An adhesive composition for a fuel cell is provided to improve an adhesion between separators and to minimize a deformation of a membrane-electrode assembly by providing a movable space for separators upon an increase in internal pressure of a fuel cell. An adhesive composition for a fuel cell includes an adhesive resin and a hardener. The adhesive resin is selected from the group comprising nitrile-based rubbers, acrylic resins, epoxy-based resins, and mixtures thereof. A fuel cell(110) includes: a membrane-electrode assembly(112); separators(116) placed on both surfaces of the membrane-electrode assembly; and at least one electricity generator(111) having a sealing part(118) that is interposed between the membrane-electrode assembly and both separators and maintains airtightness between the membrane-electrode assembly and separators. The sealing part is formed by the adhesive composition.

Description

Adhesive composition for fuel cell, fuel cell manufactured therefrom, and method for manufacturing fuel cell using same {ADHESIVE COMPOSITION FOR FUEL CELL, FUEL CELL MANUFACTURED THEREFROM AND METHOD FOR PREPARING FUEL CELL USING SAME}

1 is an exploded perspective view schematically showing an example of a stack for a fuel cell of the present invention.

Figure 2 is a schematic diagram showing the structure of a membrane-electrode assembly according to another embodiment of the present invention.

[Industrial use]

The present invention relates to an adhesive composition for a fuel cell, a fuel cell manufactured therefrom, and a method for manufacturing a fuel cell using the same, and more particularly, has excellent adhesion and elasticity, thereby improving adhesion between separators, and further, internal pressure of the fuel cell. The present invention relates to an adhesive composition for a fuel cell, a fuel cell manufactured therefrom, and a method for manufacturing a fuel cell using the same, which can provide a space in which the separator can move to minimize the deformation of the membrane-electrode assembly.

[Prior art]

A fuel cell is a power generation system that directly converts the chemical reaction energy of hydrogen and oxygen contained in hydrocarbon-based materials such as methanol, ethanol and natural gas into electrical energy.

This fuel cell is a clean energy source that can replace fossil energy, and has the advantage of generating a wide range of outputs by stacking unit cells, and having an energy density of 4-10 times that of a small lithium battery. It is attracting attention as a compact and mobile portable power source.

Representative examples of the fuel cell include a polymer electrolyte fuel cell (PEMFC) and a direct oxidation fuel cell (Direct Oxidation Fuel Cell). The use of methanol as fuel in the direct oxidation fuel cell is called a direct methanol fuel cell (DMFC).

The polymer electrolyte fuel cell has an advantage of having a high energy density and a high output, but requires attention to handling hydrogen gas and reforms fuel for reforming methane, methanol, natural gas, etc. to produce hydrogen as fuel gas. There is a problem that requires additional equipment such as a device.

On the other hand, the direct oxidation fuel cell has a lower energy density than the polymer electrolyte fuel cell, but it is easy to handle fuel and has a low operating temperature, so that it can be operated at room temperature, in particular, it does not require a fuel reformer.

In such fuel cell systems, the stack that substantially generates electricity comprises several unit cells consisting of a membrane-electrode assembly (MEA) and a separator (also called a bipolar plate). It has a structure laminated to several tens. The membrane-electrode assembly is called an anode electrode (also called a “fuel electrode” or an “oxide electrode”) and a cathode electrode (one side “air electrode” or “reduction electrode”) with a polymer electrolyte membrane including a hydrogen ion conductive polymer therebetween. ) Is located.

 The principle of generating electricity in a fuel cell is that fuel is supplied to an anode electrode, which is a fuel electrode, adsorbed to a catalyst of the anode electrode, and the fuel is oxidized to generate hydrogen ions and electrons. Reaching the cathode electrode, hydrogen ions pass through the polymer electrolyte membrane and are delivered to the cathode electrode. An oxidant is supplied to the cathode, and the oxidant, hydrogen ions, and electrons react on the catalyst of the cathode to generate electricity while generating water.

An object of the present invention is to improve the adhesion between the separator in the fuel cell by having excellent adhesion and elasticity, and also to provide a space for the separator to move when the pressure inside the fuel cell increases, thereby minimizing the deformation of the membrane-electrode assembly. It is to provide an adhesive composition for a fuel cell.

Another object of the present invention is to provide a fuel cell comprising a sealing portion formed from the adhesive composition for a fuel cell.

Still another object of the present invention is to provide a method of manufacturing a fuel cell using the adhesive composition for a fuel cell.

In order to achieve the above object, the adhesive composition for a fuel cell according to an embodiment of the present invention includes an adhesive resin and a curing agent, wherein the adhesive resin is a nitrile rubber, an acrylic resin, an epoxy resin, and a mixture thereof. It is selected from the group consisting of.

According to another embodiment of the present invention, a membrane-electrode assembly, a separator located on both sides of the membrane-electrode assembly, and an airtight portion between the membrane-electrode assembly and the separator interposed at an edge portion between the membrane-electrode assembly and both separators. It provides a fuel cell comprising at least one electricity generating unit including a sealing unit for maintaining. The sealing portion is formed from the adhesive composition.

The present invention also provides a method of manufacturing a fuel cell comprising bonding one surface of a separator to both sides of a membrane-electrode assembly using the adhesive composition, and heat-treating or irradiating light to seal the membrane-electrode assembly and the separator. .

Hereinafter, the present invention will be described in more detail.

In general, when the stack is fastened, each membrane-electrode assembly and the separator are first sealed with a sealing agent, and then a second fastening method is performed using bolts and nuts. At this time, the sealing is incomplete due to the low adhesive strength when the sealing agent is used alone, and the fastening method using bolts and nuts also causes deformation of the membrane-electrode assembly and blockage of the flow path of the separator due to excessive fastening pressure. There was a problem that the performance of the battery is reduced.

In contrast, the present invention seals each membrane-electrode assembly and separator of a fuel cell using an adhesive composition comprising a polymer resin having excellent adhesion and elasticity, thereby improving adhesion between the membrane-electrode assembly, the separator, and the separator and the separator. In addition, it provides a space for the separator to move when the pressure inside the fuel cell increases, thereby minimizing the deformation of the membrane-electrode assembly, thereby improving the performance of the fuel cell.

That is, the adhesive composition for a fuel cell according to an embodiment of the present invention includes an adhesive resin and a curing agent.

The adhesive resin is to impart thermosetting and adhesion to the adhesive composition, it is preferable to use one selected from the group consisting of nitrile rubber, acrylic resin, epoxy resin, and mixtures thereof. More preferably, the adhesive resin is selected from the group consisting of nitrile rubbers, epoxy resins, and mixtures thereof having chemical resistance to hydrocarbon additives such as methanol and acid additives to the fuels such as carboxylic acids. It is good to use.

The curing agent serves to cure the adhesive composition, specifically, a polyamine resin; Polyamide resins; Acid anhydrides; Latent curing agents such as oxazolidine, ketamine or aldimine and mixtures thereof can be used. Specific examples thereof include amido-polyamine, oxazolidine, ketamine, and aldimine.

The curing agent may be appropriately added according to the equivalent ratio to the functional group of the resin, preferably 10 to 50 parts by weight, more preferably 30 to 50 parts by weight based on 100 parts by weight of the adhesive resin. Can be.

In addition to the above components, the adhesive composition may optionally further include additives such as a reinforcing agent and a softening agent according to each purpose.

The reinforcing filler may be used as long as the elastic modulus is higher than that of the adhesive resin and is electrically insulating. Powdered reinforcing agents such as aluminum hydroxide, magnesium hydroxide, talc, alumina, magnesia, silica, titanium dioxide, calcium silicate, aluminum silicate, calcium carbonate, clay, silicon nitride, silicon carbide, aluminum borate, synthetic mica; Short-fiber reinforcing agents such as glass, asbestos, rock wool and aramid; Or whiskers such as silicon carbide, alumina and aluminum borate.

The reinforcing agent is preferably included in 5 to 30 parts by weight, more preferably 10 to 20 parts by weight with respect to 100 parts by weight of the adhesive resin. If the content of the reinforcing agent is less than 5 parts by weight, the effect is insignificant and undesirable. If the content of the reinforcing agent is more than 30 parts by weight, it is not preferable because of leaching or non-uniform dispersion due to aggregation.

In addition, the flexibilizer serves to impart elasticity to the adhesive composition, and specifically, one or more selected from the group consisting of glycerol, 2-butene-1,4-diol, and polyethylene glycol may be used. .

The softening agent is preferably included in 3 to 15 parts by weight, more preferably 5 to 10 parts by weight with respect to 100 parts by weight of the adhesive resin. If the content of the softening agent is less than 3 parts by weight, the effect is negligible, and if it exceeds 15 parts by weight, there is a fear of migration due to low surface energy.

The adhesive composition having the composition as described above can be cured after being applied to a sealing portion interposed between the membrane-electrode assembly and the separator between the separators, thereby maintaining airtightness between the membrane-electrode assembly and the separator.

Since the adhesive composition does not contain a solvent, it is easy to work when sealing and is cured by heat treatment or light irradiation, so that the adhesion process may be rapid and excellent adhesion may be provided. In addition, the adhesive composition may have elasticity to provide a space for the separator to move when the pressure inside the fuel cell increases, thereby minimizing deformation of the membrane-electrode assembly. As a result, the performance of the fuel cell can be improved.

The present invention also provides a fuel cell comprising a sealing portion made from the adhesive composition.

That is, the fuel cell according to another embodiment of the present invention, the membrane-electrode assembly; Separators on both sides of the membrane-electrode assembly; And at least one electricity generating part interposed at an edge portion between the membrane-electrode assembly and both separators to maintain an airtight between the membrane-electrode assembly and the separator, wherein the sealing part comprises the adhesive composition for the fuel cell. Is formed by.

More preferably, the sealing part may include a gasket interposed between the membrane-electrode assembly and the separator, and a sealing film interposed between the gasket and the separator and between the gasket and the membrane electrode assembly.

1 is an exploded perspective view schematically showing a fuel cell according to an embodiment of the present invention.

Referring to FIG. 1, a fuel cell 110 according to an embodiment of the present invention may include a single or a plurality of electricity generating units 111 that generate electric energy by inducing oxidation / reduction reaction of hydrogen gas and oxygen. Include. The electricity generating unit 111 may be included in the fuel cell in a state where one or two or more are stacked as needed, and the number of the stacked electrical generating units may be adjusted according to the required output voltage.

Each of the electric generators 111 is a membrane electrode assembly (membrane-electrode assembly) for oxidizing / reducing hydrogen gas and oxygen in air (hereinafter, referred to as a membrane-electrode assembly). A separator 116 positioned to contact both surfaces of the membrane electrode assembly and supplying hydrogen gas and oxygen to the membrane electrode assembly 112, and between the membrane electrode assembly 112 and both separators 116. It includes a sealing portion 118 interposed at the edge portion to maintain the airtight between the membrane-electrode assembly 112 and the separator 116.

The sealing portion 118 includes a sealing film 117 made by an adhesive composition according to an embodiment of the present invention, and optionally also an edge portion between the membrane-electrode assembly 112 and the separator 116. A gasket 119 may be interposed between the membrane-electrode assembly 112 and the separator 116 by the sealing layer 117.

The membrane-electrode assembly 112 also includes a polymer electrolyte membrane (not shown) for fuel cells, an anode electrode formed on one surface and an cathode electrode formed on the other surface at intervals inwardly from an outer edge of the polymer electrolyte membrane. ).

2 is a view schematically showing the structure of a membrane-electrode assembly according to an embodiment of the present invention. Referring to FIG. 2, the membrane-electrode assembly 112 includes a cathode electrode 20 and an anode electrode 20 ′ facing each other, and between the cathode electrode 20 and the anode electrode 20 ′. It comprises a polymer electrolyte membrane (10) located.

The cathode electrode 20 and the anode electrode 20 'include an electrode substrate 40 and 40' and a catalyst layer 30 and 30 ', respectively.

The electrode substrates 40 and 40 'serve to support the electrode and diffuse fuel and oxidant to the catalyst layers 30 and 30', thereby easily accessing the fuel and oxidant to the catalyst layer.

As the electrode substrates 40 and 40 ', conductive substrates are used, and representative examples thereof include carbon paper, carbon cloth, carbon felt, or metal cloth (porous material composed of metal cloth in fiber state). It means that the metal film is formed on the surface of the film or the cloth formed of polymer fibers) may be used, but is not limited thereto.

In addition, using the water-repellent treatment with a fluorine-based resin as the electrode substrates 40 and 40 'can prevent the reactant diffusion efficiency from being lowered by the electrochemically generated water in the catalyst layer of the cathode when the fuel cell is driven. It is preferable. Examples of the fluorine-based resin include polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonyl fluoride alkoxy vinyl ether, and fluorinated ethylene propylene ( Fluorinated ethylene propylene), polychlorotrifluoroethylene or copolymers thereof can be used.

Catalyst layers 30 and 30 'are positioned on the electrode substrates 40 and 40'.

The catalyst layers 30 and 30 'catalyze the associated reactions (oxidation of fuel and reduction of oxidant) and include a catalyst.

As the catalyst, any one that can be used as a catalyst may participate in the reaction of the fuel cell, and as a representative example, a platinum-based catalyst may be used. As the platinum-based catalyst, platinum, ruthenium, osmium, platinum-ruthenium alloy, platinum-osmium alloy, platinum-palladium alloy, platinum-M alloy (M is Ga, Ti, V, Cr, Mn, Fe, Co, Ni, Transition metals selected from the group consisting of Cu, Zn, Sn, Mo, W, Rh, and combinations thereof), and mixtures thereof. As described above, the anode electrode and the cathode electrode may use the same material, but in order to prevent the catalyst poisoning caused by CO generated during the anode electrode reaction in the direct oxidation fuel cell, a platinum-ruthenium alloy catalyst is used as the anode. It is more preferable as an electrode catalyst. Specific examples include Pt, Pt / Ru, Pt / W, Pt / Ni, Pt / Sn, Pt / Mo, Pt / Pd, Pt / Fe, Pt / Cr, Pt / Co, Pt / Ru / W, Pt / Ru / Mo, Pt / Ru / V, Pt / Fe / Co, Pt / Ru / Rh / Ni, Pt / Ru / Sn / W, and mixtures thereof may be used.

In addition, such a catalyst may be used as the catalyst itself (black), or may be used on a carrier. As the carrier, carbon-based materials such as graphite, denka black, ketjen black, acetylene black, carbon nanotube, carbon nanofiber, carbon nanowire, carbon nanoball, or activated carbon may be used, and alumina, silica, zirconia, Or inorganic fine particles such as titania may be used, but carbon-based materials are generally used.

The catalyst layers 30 and 30 'may further include a binder resin to improve adhesion of the catalyst layer and transfer of hydrogen ions.

It is preferable to use a polymer resin having hydrogen ion conductivity as the binder resin, more preferably a cation exchange group selected from the group consisting of sulfonic acid group, carboxylic acid group, phosphoric acid group, phosphonic acid group and derivatives thereof in the side chain. Any polymer resin which has can be used. Preferably, a fluorine polymer, a benzimidazole polymer, a polyimide polymer, a polyetherimide polymer, a polyphenylene sulfide polymer, a polysulfone polymer, a polyether sulfone polymer, a polyether ketone polymer, a polyether A hydrogen ion conductive polymer selected from the group consisting of ether ketone polymers, polyphenylquinoxaline polymers, and combinations thereof can be used. More preferably poly (perfluorosulfonic acid), poly (perfluorocarboxylic acid), copolymers of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid groups, defluorinated sulfided polyether ketones, aryl ketones, Poly (2,2'-m-phenylene) -5,5'-bibenzimidazole (poly (2,2 '-(m-phenylene) -5,5'-bibenzimidazole), poly (2,5- Benzimidazole), and a hydrogen ion conductive polymer selected from the group consisting of these may be used.

The binder resin may be used in the form of a single substance or a mixture, and may also be optionally used with a nonconductive compound for the purpose of further improving adhesion to the polymer electrolyte membrane. It is preferable to adjust the usage-amount so that it may be suitable for a purpose of use.

Examples of the non-conductive compound include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro alkylvinylether copolymer (PFA), and ethylene / tetrafluoro Ethylene / tetrafluoroethylene (ETFE), ethylenechlorotrifluoro-ethylene copolymer (ECTFE), polyvinylidene fluoride, copolymer of polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), dode More preferably, it is selected from the group consisting of silbenzenesulfonic acid, sorbitol, and combinations thereof.

In addition, the membrane electrode assembly 110 according to the present invention may be further formed with a microporous layer (not shown) to enhance the diffusion effect of the reactants in the electrode substrate. These microporous layers are generally conductive powders having a small particle diameter, such as carbon powder, carbon black, acetylene black, activated carbon, carbon fiber, fullerene, carbon nanotubes, carbon nanowires, and carbon nanohorns. -horn or carbon nano ring, and the like.

The microporous layer is prepared by coating a composition comprising a conductive powder, a binder resin and a solvent on the electrode substrate. As the binder resin, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol, cellulose acetate, and the like may be preferably used. The solvent may be ethanol, isopropyl alcohol, n-propyl alcohol, butyl alcohol, or the like. Alcohol, water, dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone and the like can be preferably used. The coating process may be a screen printing method, a spray coating method or a coating method using a doctor blade or the like depending on the viscosity of the composition, but is not limited thereto.

The polymer electrolyte membrane 10 is positioned between the anode electrode 20 'and the cathode electrode 20 having the above structure.

The polymer electrolyte membrane functions as an ion exchange to transfer hydrogen ions generated in the catalyst layer of the anode electrode to the catalyst layer of the cathode electrode, and is generally used as a polymer electrolyte membrane in a fuel cell and is made of a polymer resin having hydrogen ion conductivity. Anything can be used. Representative examples thereof include a polymer resin having a cation exchange group selected from the group consisting of sulfonic acid group, carboxylic acid group, phosphoric acid group, phosphonic acid group and derivatives thereof in the side chain.

Specific examples of the polymer resin include fluorine polymer, benzimidazole polymer, polyimide polymer, polyetherimide polymer, polyphenylene sulfide polymer, polysulfone polymer, polyether sulfone polymer, polyether ketone Polymers, polyether-etherketone-based polymers, polyphenylquinoxaline-based polymers, copolymers thereof, and mixtures thereof, and more preferably poly (perfluorosulfonic acid) (generally Nafion). Commercially available), poly (perfluorocarboxylic acid), copolymers of tetrafluoroethylene and fluorovinylethers containing sulfonic acid groups, defluorinated sulfided polyetherketones, aryl ketones, poly (2,2'-m -Phenylene) -5,5'-bibenzimidazole (poly (2,2 '-(m-phenylene) -5,5'-bibenzimidazole), poly (2,5-benzimidazole), their air In coalescing and mixtures thereof It can be given that choice.

It is also possible to substitute H with Na, K, Li, Cs or tetrabutylammonium in the cation exchanger of such a hydrogen ion conductive polymer. In the cation exchanger of the hydrogen-ion conductive polymer, NaOH is substituted when H is replaced with Na, and tetrabutylammonium hydroxide is substituted when replacing with tetrabutylammonium, and K, Li or Cs may be substituted with an appropriate compound. It can be substituted. Since this substitution method is well known in the art, detailed description thereof will be omitted.

The separator 116 is positioned at both sides of the membrane-electrode assembly 112 having the above configuration.

The separator 116 is disposed in close contact with each other with the membrane-electrode assembly 112 interposed therebetween, and includes a hydrogen passage 116a and an air passage 116b on both sides of the membrane-electrode assembly 112, respectively. The hydrogen passage 116a is located on the anode electrode side of the membrane-electrode assembly 112, and the air passage 116b is located on the cathode electrode side of the membrane-electrode assembly 112. The separator 116 functions as a conductor that connects the anode electrode and the cathode electrode in series in addition to supplying hydrogen gas and oxygen in the air to the membrane electrode assembly 112. In addition, the separator 116 corresponds to the membrane-electrode assembly, and includes a first region A that forms a hydrogen passage 116a and an air passage 116b with respect to one surface of the body, and an outside of the first region A. It may be divided into a second area (B) corresponding to the edge of.

The separator may be a metal substrate such as stainless steel 303, 310, 316, 316L or 904L, an aluminum alloy, titanium, or a titanium alloy, but is not limited thereto. In addition, in order to increase adhesion between the membrane-electrode assembly and the separator in fuel cell manufacturing, polarization, sand papering, corona treatment, rubbing, pressing, plasma irradiation, The surface roughness may be increased by surface treatment by a method such as a replica which presses with a mesh to form roughness.

In addition, the outermost portion of the fuel cell 110 may be in contact with the plurality of electricity generating units 111, and a separate press plate 113 may be installed to fasten the electricity generating units 111. Also, optionally, the fuel cell 110 according to the embodiment of the present invention excludes the pressurizing plate 113, and the separator 116 located at the outermost part of the electricity generating unit 111 may include the pressurizing plate. It can also be configured to take on a role. In addition, the pressure plate 113 may be configured to have a function unique to the separator 116 in addition to the function of bringing the plurality of electricity generating units 111 into close contact.

A sealing unit 118 is formed between the membrane-electrode assembly 112 and the separator 116.

The sealing part 118 is interposed between the membrane-electrode assembly 112 and the separator 116 and serves to maintain the airtight between the membrane-electrode assembly 112 and the separator 116. The sealing part 118 may be formed by an adhesive composition according to an embodiment of the present invention, and more preferably, the sealing part is interposed at an edge portion between the membrane-electrode assembly 112 and the separator 116. The gasket 119, and a sealing film 117 formed on both sides of the gasket.

The sealing film 117 may be formed in the second region B of each separator 116 formed on both sides of the membrane-electrode assembly or on the surface of the gasket 119 in close contact with the separator. The sealing film 117 may be formed by applying the complex composition to the surface of the second region (B) or the gasket 119 of the separator to a predetermined thickness and then curing by heat treatment or light irradiation. When the sealing film 117 formed as described above is pressed against both separators 116 with the membrane-electrode assembly 112 at the center to bring them into close contact with each other, the sealing film 117 is formed on the surface of both separators 116, or It is adhered to the surface of the second region B of the separator 116 and the gasket 119 to improve the adhesion between the separators 116 or the separator 116 and the gasket 119, and the pressing force of both separators 116 It serves to seal a gap between both separators 116 or a gap between separator 116 and gasket 119 that may be caused by a difference. In addition, even if the pressing force applied to the separator 116 is not uniform, the sealing film 117 is in close contact with the contact surface of the gasket 119 and the contact surface of the separator 116, so that the pressure applied to the separator 116 is applied to the gasket (116). The gasket 119 and the separator 116 may be sealed while being uniformly dispersed in the 119, thereby improving airtightness between the membrane-electrode assembly 112 and the separator 116.

The gasket 119 is in close contact with the second region B of the separator 116 by the sealing film 117 and is supplied to the membrane-electrode assembly 112 through the passages 116a and 116b of the separator 116. It prevents hydrogen gas and air from leaking out or mixing with each other. The gasket 119 is made of a rubber material, for example, silicone, fluorine, or olefin rubber material, which is an elastic material, and is configured to be connected to the edge portion of the membrane-electrode assembly 112. Therefore, in the process of forming the fuel cell 110 by bringing the plurality of electricity generating parts 111 into close contact with each other through the pressure plate 113, when the surface of the gasket 119 receives the compressive force of both separators 116, the elastic region is in the elastic region. By properly contracting at and maintaining a surface pressure necessary for gas sealing between the separator 116 and the membrane-electrode assembly 112, it is possible to prevent gas leakage during operation of the stack 110.

The fuel cell according to the exemplary embodiment of the present invention configured as described above is formed by bringing a plurality of electricity generating units into close contact with each other through a pressure plate and fastening them. Therefore, when the hydrogen gas supplied from the reformer and the air sucked by the air pump are supplied to the electricity generator of the fuel cell, the electricity generator generates electricity, water, and water through an electrochemical reaction between hydrogen gas and oxygen contained in the air. It generates heat.

According to another embodiment of the present invention, there is provided a method of manufacturing a fuel cell having the above configuration.

That is, the method of manufacturing the fuel cell includes bonding one surface of the separator to both sides of the membrane-electrode assembly using an adhesive composition, and sealing the membrane-electrode assembly and the separator by heat treatment or light irradiation.

First, the separators are positioned on both sides of the membrane-electrode assembly, and then the adhesive composition is applied to the outer edge portion of the region corresponding to the membrane-electrode assembly of the separator to bond both separators.

The adhesive composition and the separator are the same as described above. However, the separator may be polarized by radiation to the surface of the separator in order to increase the adhesive strength between the separators prior to the application of the adhesive composition, or may be sand papered, sandblasted, corona treated, or rubbed. It can be surface-treated by a method such as a pressing method or a plasma irradiation.

The coating process is selected from the group consisting of a spray method, a screen printing method, a spray coating method, a coating method using a doctor blade, a gravure coating method, a dip coating method, a silk screen method, a painting method, and a slot die method. It may be carried out by the method, but is not limited to these.

Next, the bonded separators are heat treated or irradiated with light to produce a fuel cell. The adhesive composition is cured by such heat treatment or light irradiation to form a sealing portion.

When heat-processing first, it is preferable to carry out at 10-190 degreeC, More preferably, it can carry out at 80-100 degreeC. If the heat treatment temperature is less than 10, solvents and the like remain undesirably. If the heat treatment temperature exceeds 130 ° C, the curing rate rapidly increases and the optimum curing is not reached, which is not preferable.

In the case of light irradiation, a halogen lamp, a high pressure mercury lamp, a laser light, a metal halogen lamp, a black lamp, an electrodeless lamp, etc. may be used as the light source.

In addition, when the fuel cell includes a gasket, the method may include adhering the gasket to both sides of the membrane-electrode assembly prior to the adhesion of the separator.

At this time, the order of adhesion of the membrane-electrode assembly and the gasket, the gasket and the separator is not particularly limited, and the membrane-electrode assembly and the gasket are first adhered to each other and then the separator is adhered to each other, The membrane-electrode assembly and the gasket may be bonded. In addition, the sealing process may be carried out after each bonding process, or the gasket and the separator may be bonded to the membrane-electrode assembly, and may be sealed by heat treatment or light irradiation at a time.

Also, when the membrane electrode assembly and the gasket are bonded to each other, the gasket may not overlap with the anode electrode or the cathode electrode of the membrane electrode assembly, and one surface of the gasket may be attached to both sides of the polymer electrolyte membrane exposed at the edge of the membrane electrode assembly. It is preferable to adhere with the composition.

The fuel cell manufactured using the adhesive composition as described above has excellent adhesion between the separators and minimizes deformation of the membrane-electrode assembly due to an increase in internal pressure in the stack due to elasticity of the sealing portion in the separator. As a result, the performance of the fuel cell is also improved.

Hereinafter, preferred examples and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention and the present invention is not limited to the following examples.

 Example 1

To 100 parts by weight of epoxy resin, 15 parts by weight of silica powder, 10 parts by weight of 2-butene-1,4-diol, and 10 parts by weight of amidopolyamine were mixed to prepare an adhesive composition for a fuel cell.

After forming a cathode electrode layer and an anode electrode layer each containing a platinum catalyst on two carbon cloths, the cathode electrode layer and the anode electrode layer were respectively formed on both sides of a poly (perfluorosulfonic acid) film (NAFION ^TM manufactured by DuPont). The membrane-electrode assembly was prepared by laminating them in contact with each other.

The adhesive composition was applied to one surface of two previously prepared gaskets, and the two gaskets were adhered to both sides of a polymer electrolyte membrane on the outer edge of the prepared membrane-electrode assembly. In addition, each of the other side of the gasket was applied to the adhesive composition prepared, and the separator is formed on both sides of the membrane-electrode assembly to which the gasket is adhered. At this time, the separator was polarized by irradiation.

Next, a heat treatment was performed at 120 ° C. to seal the fuel cell.

Example 2

With respect to 100 parts by weight of epoxy resin, the same as in Example 2 except for using a fuel cell adhesive composition prepared by mixing 5 parts by weight of short-fiber rock wool powder, 5 parts by weight of glycerol, and 10 parts by weight of oxazolidine The fuel cell was manufactured by the method.

Example 3

With respect to 100 parts by weight of polymethyl methacrylate, except for using an adhesive composition for a fuel cell prepared by mixing 30 parts by weight of silicon carbide powder, 10 parts by weight of glycerol, and 30 parts by weight of amidopolyamine, A fuel cell was prepared in the same manner.

Example 4

The fuel cell adhesive composition prepared by mixing 10 parts by weight of alumina powder, 3 parts by weight of glycerol, and 17 parts by weight of amidopolyamine with respect to 100 parts by weight of the nitrile rubber was used in the same manner as in Example 2. To produce a fuel cell.

Example 5

It carried out by the same method as Example 2 except having used the adhesive composition for fuel cells manufactured by mixing 20 weight part of silicon nitride powders, 15 weight part of glycerol, and 50 weight part of polyamide resins with respect to 100 weight part of acrylic resins. To produce a fuel cell.

 Comparative Example 1

After forming a cathode electrode layer and an anode electrode layer each containing a platinum catalyst on two carbon cloths, the cathode electrode layer and the anode electrode layer were formed on both sides of a poly (perfluorosulfonic acid) film (NAFION ^TM manufactured by DuPont). Each of them was laminated so as to contact each other to prepare a membrane-electrode assembly.

2-cyanoacrylate was applied to one surface of two previously prepared gaskets, and the two gaskets were adhered to both sides of an electrolyte membrane of an outer edge of the prepared membrane-electrode assembly. In addition, 2-cyano acrylate was applied to the other side of the gasket, and a separator having a flow path was laminated on both sides of the membrane-electrode assembly to which the gasket was bonded to manufacture a fuel cell. At this time, the separator was polarized by irradiation.

In addition, the output change of the unit cell according to the battery temperature and the methanol concentration was measured in the state in which methanol and air were introduced into the fuel cells prepared according to Example 1 and Comparative Example 1. The measurement results are shown in Table 1 below.

Power density at 60 ℃ (mW / cm ² at 0.4 V) Example 1 110 Comparative Example 1 85

As shown in Table 1, the fuel cell of Example 1 sealed by the adhesive composition according to the present invention showed an excellent power density compared to the fuel cell of Comparative Example 1. This is considered to be because the adhesive composition of Example 1 has improved adhesion between the separators due to excellent adhesion and elasticity, and also prevents deformation of the membrane-electrode assembly due to increased internal pressure in the stack.

The fuel cell in Example 2-5 was also subjected to the same method as described above to evaluate the output characteristics.

As a result, an output density equivalent to that of the fuel cell of Example 1 was shown.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

By sealing the fuel cell with the fuel cell adhesive composition according to the present invention, the adhesion between the separators can be improved and the elasticity of the adhesive composition can minimize the deformation of the membrane-electrode assembly due to the pressure increase in the fuel cell. As a result, the performance of the fuel cell can be improved.

Claims (19)

Comprising an adhesive resin and a curing agent, The adhesive resin is a fuel cell adhesive composition selected from the group consisting of nitrile rubber, acrylic resin, epoxy resin, and mixtures thereof. The method of claim 1, The adhesive resin is a fuel cell adhesive composition selected from the group consisting of nitrile rubber, epoxy resin and mixtures thereof. The method of claim 1, Wherein the curing agent is selected from the group consisting of polyamine-based resins, polyamide resins, acid anhydrides, latent curing agents and mixtures thereof. The method of claim 3, wherein The latent curing agent is an adhesive composition for a fuel cell is selected from the group consisting of oxazolidine, ketamine, aldimine and mixtures thereof. The method of claim 1, The curing agent is a fuel cell adhesive composition is contained in 10 to 50 parts by weight based on 100 parts by weight of the adhesive resin. The method of claim 1, The adhesive composition is a fuel cell adhesive composition comprising an epoxy resin and a latent curing agent. The method of claim 1, The adhesive composition further comprises an additive selected from the group consisting of reinforcing agents, softening agents, and mixtures thereof. The method of claim 7, wherein The reinforcing agent is an adhesive composition for a fuel cell is included in 5 to 30 parts by weight based on 100 parts by weight of the adhesive resin. The method of claim 7, wherein The reinforcing agent is aluminum hydroxide, magnesium hydroxide, talc, alumina, magnesia, silica, titanium dioxide, calcium silicate, aluminum silicate, calcium carbonate, clay, silicon nitride, silicon carbide, aluminum borate, synthetic mica, glass, asbestos, rock wool, aramid carbide Adhesive composition for a fuel cell which is selected from the group consisting of silicon, alumina, aluminum borate, and mixtures thereof. The method of claim 7, wherein The softening agent is an adhesive composition for a fuel cell that is contained in 3 to 15 parts by weight based on 100 parts by weight of the adhesive resin. The method of claim 7, wherein The softener is selected from the group consisting of glycerol, 2-butene-1,4-diol, polyethylene glycol, and mixtures thereof. Membrane-electrode assembly; Separators on both sides of the membrane-electrode assembly; And At least one electricity generating portion interposed at an edge portion between the membrane electrode assembly and both separators and including a sealing portion for maintaining airtightness between the membrane electrode assembly and the separator; The sealing unit is a fuel cell formed by the adhesive composition according to any one of claims 1 to 11. The method of claim 12, The separator includes a first region of a portion corresponding to the membrane-electrode assembly, and a second region of an outer edge portion of the first region, And the sealing portion is formed between the second regions of both separators. The method of claim 13, And the sealing part includes a gasket interposed between the membrane-electrode assembly and the separator, and a sealing film interposed between the gasket and the separator and between the gasket and the membrane-electrode assembly. A fuel cell comprising the step of adhering one side of a separator to both sides of the membrane-electrode assembly using the adhesive composition according to any one of claims 1 to 11, followed by heat treatment or light irradiation to seal the membrane-electrode assembly and the separator. Method of preparation. The method of claim 15, Wherein the adhesive composition is applied to the outer edge portion of the region corresponding to the membrane-electrode assembly of the separator. The method of claim 15, The separator is surface-treated by a method selected from the group consisting of radiation, sand papering, sandblasting, corona treatment, rubbing, pressing, plasma irradiation, replica and combinations thereof. Way. The method of claim 15, And bonding a gasket to both surfaces of the membrane-electrode assembly before adhesion of the separator. The method of claim 15, The heat treatment process is a manufacturing method of a fuel cell that is carried out at 10 to 190 ℃.

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