JP2006049248A - Thermal transfer sheet and lamination body for solid oxide fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer sheet which can be formed on a solid oxide fuel cell of various surface states, capable of obtaining stable battery characteristics. <P>SOLUTION: An electrode forming layer 3 or an electrolyte forming layer for thermally transferring on a material to be transferred is formed by printing a paste 4 formed by mixing an electrode forming material for a solid oxide fuel cell or an electrolyte forming material for the same and a binder containing thermoplastic resin on a base material 2 with a peeling property having a smooth surface, and by drying the paste. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal transfer sheet used for manufacturing a solid oxide fuel cell (SOFC).

  Conventionally, in general, a solid oxide fuel cell has a structure in which a fuel electrode is disposed on one surface of an electrolyte and an air electrode is disposed on the other surface through an electrolyte made of a solid oxide having oxygen ion conductivity. By supplying fuel gas to the electrode side and supplying oxidant gas to the air electrode side, it is possible to generate an electrochemical reaction and obtain electric power.

  As for the electrolyte and electrode of such a solid oxide fuel cell, a wet method is known in which a material used for the electrolyte is made into a paste and applied onto one electrode or the electrolyte, followed by firing to form a film. ing. As such a wet method, a screen printing method, a spray coating method, a dipping method, an electrophoretic electrodeposition method and the like are known.

  As another method for forming the electrolyte and the electrode, there is a dry method, and film forming methods such as CVD, EVD, and sputtering are also known.

  In producing a solid oxide fuel cell, in order to ensure battery performance, the thickness of the electrolyte and the electrode, and the necessity, are not affected by the electrode on which the electrolyte is placed, the material of the electrolyte on which the electrode is placed, the surface condition, etc. It is necessary to control and manufacture the electrolyte itself or the planar shape of the electrode itself as designed according to the intended use.

  However, in the above conventional film forming method, if unevenness occurs in the surface state of the surface on which the electrolyte or electrode is laminated, the film thickness changes, so that the planar shape of the electrolyte itself or the electrode itself does not become as designed. There was a thing.

  In addition, SOFC generally has a problem that the production efficiency is low because cells are manufactured using the above-described film forming method such as screen printing for each sheet on which an electrode or an electrolyte substrate is formed.

  Therefore, in view of the above-described conventional problems, the present invention can be formed for various surface states, can provide stable cell performance, and can improve production efficiency. It is an object of the present invention to provide a laminate for a solid oxide fuel cell in which the thermal transfer sheet and the solid oxide fuel cell thermal transfer sheet are laminated.

  In order to achieve the above object, the thermal transfer sheet for a solid oxide fuel cell according to the present invention is formed on the smooth surface of a peelable substrate having a smooth surface, or an electrode forming material for a solid oxide fuel cell or a solid oxide. It is characterized in that an electrode forming layer or an electrolyte forming layer for thermal transfer to a transfer target is formed by printing and drying a paste in which an electrolyte forming material for a solid fuel cell and a binder containing a thermoplastic resin are mixed and dried. To do.

  It is preferable to further laminate a heat sealable resin layer on the upper surface of the electrode forming layer or the electrolyte forming layer.

  It is preferable that the binder and the heat sealable resin layer contain the same thermoplastic resin.

  The peelable substrate is preferably a synthetic resin film or sheet that has been matted.

  As for the said peelable base material, the peeling layer may be formed in the surface of a film or a sheet | seat.

  The laminate for a solid oxide fuel cell according to the present invention is characterized in that the electrode forming layer of the thermal transfer sheet for the solid oxide fuel cell that has been thermally transferred is thermally transferred onto the solid electrolyte.

  According to the present invention, a paste in which a solid oxide fuel cell electrode forming material or a solid oxide fuel cell electrolyte forming material and a binder containing a thermoplastic resin are mixed is printed and dried on a peelable substrate. Can be sintered after transferring the solid oxide fuel cell thermal transfer sheet on which the electrode forming layer or the electrolyte forming layer for thermal transfer to the transferred body is transferred to the transferred body If the surface is smooth, an accurate film thickness and film shape can be obtained, and stable battery performance can be obtained.

  In addition, by forming the peelable substrate with a flexible film or a flexible sheet, it is possible to form not only a flat surface but also an electrode or an electrolyte on a curved surface portion.

  Furthermore, according to the present invention, a long thermal transfer sheet can be formed by roll-to-roll (roll to roll), cut to a desired size and thermally transferred, and thus produced as a roll-like continuous sheet, Production efficiency can be increased.

  A preferred embodiment of a thermal transfer sheet for a solid oxide fuel cell according to the present invention will be described below with reference to FIGS. In addition, the same code | symbol was attached | subjected to the same component through the whole figure.

  As shown in FIG. 1, the solid oxide fuel cell thermal transfer sheet 1 has a solid oxide fuel cell electrode forming layer 3 formed on the upper surface of a peelable substrate 2.

  The peelable substrate 2 shown in FIG. 1 can be formed of a commonly used synthetic resin material. For example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer Copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, fluorine resin, poly (meth) acrylic resin, polycarbonate resin, polyethylene terephthalate or polyethylene naphthalate Polyester resins such as various polyamide resins such as nylon, polyimide resins, polyamideimide resins, polyaryl phthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyethersulfone resins , Polyurethane resins, acetal resins, cellulose resins, various resins other like can be used film or sheet having flexibility that is the material.

  The peelable substrate 2 is preferably lightweight and excellent in flexibility and workability, and it is preferable to use a film or sheet of polyethylene resin, polypropylene resin or polyester resin. . The thickness of the peelable substrate 2 can be set to, for example, 10 to 100 μm.

  The electrode forming layer 3 is a layer that becomes an electrode of a solid oxide fuel cell by sintering, and the electrode includes an air electrode or a fuel electrode.

The electrode forming layer 3 can be formed by mixing ceramic powder, which is an electrode forming material, with a binder to form a paste, printing on the peelable substrate 2 to be printed, and drying. The viscosity of the paste can be adjusted to 10 to 10 ⁵ mPa · s. The thickness of the electrode forming layer 3 can be adjusted to 1 to 1000 μm.

  The average particle size of the ceramic powder is preferably 10 nm to 100 μm, and preferably 100 nm to 10 μm. In addition, an average particle diameter can be measured according to JISZ8901, for example.

  As the ceramic powder material for forming the fuel electrode, for example, a mixture of a metal catalyst and a ceramic powder material made of an oxide ion conductor can be used. As the metal catalyst used at this time, a material that is stable in a reducing atmosphere such as nickel, iron, cobalt, noble metals (platinum, ruthenium, palladium, etc.) and has hydrogen oxidation activity can be used. In addition, as the oxide ion conductor, one having a fluorite structure or a perovskite structure can be preferably used. Examples of those having a fluorite structure include ceria-based oxides doped with samarium, gadolinium and the like, and zirconia-based oxides containing scandium and yttrium. Moreover, as what has a perovskite type structure, the lanthanum garade type oxide doped with strontium and magnesium can be illustrated. Among the above materials, it is preferable to form the fuel electrode with a mixture of an oxide ion conductor and nickel. The mixed form of the ceramic material made of the oxide ion conductor and nickel may be a physical mixed form or a form of powder modification to nickel. Moreover, the ceramic material mentioned above may be used individually by 1 type, or may mix and use 2 or more types. The fuel electrode can also be configured using a metal catalyst alone.

As the ceramic material for forming the air electrode, for example, a perovskite type metal oxide can be used. Specifically, (Sm, Sr) CoO ₃ , (La, Sr) MnO ₃ , (La, Examples include oxides such as Sr) CoO ₃ , (La, Sr) (Fe, Co) O ₃ , (La, Sr) (Fe, Co, Ni) O ₃ , preferably (La, Sr) MnO ₃ . is there. The ceramic material mentioned above is used individually by 1 type or in mixture of 2 or more types.

  The binder includes an organic resin and a solvent. The organic resin contained in the binder needs to be combusted / decomposed / vaporized at a low temperature during the baking process, and a thermoplastic resin such as an acrylic resin, a styrene resin, an ethyl cellulose derivative, or a styrene acrylic copolymer is used alone. Or it can be mixed and used. The solvent contained in the binder is preferably selected so as not to dissolve the organic resin easily but only to swell. As such a solvent, ketones, esters, ethers, amides and the like can be used alone or in combination. Specifically, isopropanol, normal propanol, diacetone alcohol, glycol diacetate, Methyl cellosolve, carbitol, cyclohexane, terpineol, etc. can be used. Moreover, as a solvent, high boiling point compounds, such as glycerol, dibutyl phthalate, and dioctyl phthalate, can be used.

  If necessary, the electrolyte forming material and the organic resin binder may further include a plasticizer, a viscosity modifier, a dispersant, an antioxidant, an antistatic agent, a crosslinking agent, a curing agent, a filler, a lubricant, a foaming agent, In order to increase the strength of the layer itself, one or more reinforcing agents / reinforcing agents such as calcium carbonate and other additives can be added to the ink having a viscosity suitable for the coating method and printing suitability. Adjust.

  In particular, as one method for imparting flexibility, for example, there is a method in which a plasticizer is added and a long chain compound of an organic resin binder is left as an unreacted substance in a cured product. As the plasticizer, for example, dibutyl phthalate, ethylene glycol ester of organic acid, ethylene oxide adduct of tetrahydrofurfuryl alcohol, and the like can be used.

  As another method for imparting flexibility, there is a method in which a plasticizer having an epoxy group is added and the plasticizer and the organic resin binder (long chain compound) are reacted at the time of curing. When such a plasticizer is mixed with a long chain compound, strong adhesive force and viscoelasticity can be obtained by the epoxy group contained in the plasticizer.

  Furthermore, as another method of imparting flexibility, there is also a method of selecting and using a diluted solution. Examples of such a diluent solvent include butyl glycidyl ether, acrylic glycidyl ether, diglycidyl ether, butanediol glycidyl ether and the like. It can be illustrated.

  Printing methods include floating knife coating, knife over roll coating, inverted knife coating, squeeze roll coating, reverse roll coating, roll coating, gravure roll coating, kiss roll coating, air blade coating Coating method such as dip coating method, flow coating method, spin coating method, spray coating method, bar coating method, curtain flow coating method, etc., or gravure printing, offset printing, silk screen printing, transfer printing, Other printing methods can be used.

  The mixed paste of the electrode forming material and the binder is printed on the peelable substrate 2 and then accommodated in a drying chamber and dried at a temperature of 40 to 130 ° C. under drying conditions for 5 to 60 minutes. The formation layer 3 is formed.

  Since the solid oxide fuel cell thermal transfer sheet 1 thus obtained forms the electrode forming layer 3 on the smooth surface of the peelable substrate 2, the film thickness of the electrode forming layer 3 can be accurately controlled. . As a result, the solid oxide fuel cell thermal transfer sheet 1 having the electrode forming layer 3 was thermally transferred to an electrolyte substrate using a known thermal transfer device such as a hot press machine, and the peelable substrate 2 was peeled off. If fired, stable battery characteristics can be obtained.

  Of the thermal transfer sheet 1 for the solid oxide fuel cell according to the first embodiment, the one using an electrode forming material contains a thermoplastic resin having heat sealability as a binder, and the thermoplastic resin is used during thermal transfer. Softens, adheres to the electrolyte substrate and is transferred.

  In order to improve thermal transferability, it is preferable to use a thermoplastic resin itself having heat sealability as a binder. Examples of the thermoplastic resin having heat sealability include low density polyethylene, medium density polyethylene, high density polyethylene, linear (linear) low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, and ethylene. -Ethylene acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, polyolefin resin such as polyethylene or polypropylene, acrylic acid, methacrylic acid, Acid-modified polyolefin resins modified with unsaturated carboxylic acids such as maleic anhydride, fumaric acid, etc., polyolefin resins such as others, polyacrylic or polymethacrylic resins, polyester resins, polyamide resins, polyurethane resins There are other, and the like.

  The peelable substrate 2 can improve the peelability by matting the above-described synthetic resin film or synthetic resin sheet. The matting treatment means that the surface is given a fine unevenness to make it matt. As the matting treatment, for example, a sand mat method in which the surface of the peelable substrate formed of synthetic resin is physically uneven, a method of forming by incorporating fine particles in the peelable substrate, etc. are adopted. can do.

  The releasability can also be improved by incorporating fine particles in the releasable substrate 2, for example, inorganic fine particles such as silica, titanium oxide, calcium carbonate, talc, kaolinite, mica, acrylonitrile polymer, acrylate ester Polymer particles of hydrophobic resins such as polystyrene, polymer particles of hydrophilic resins such as polyacrylic acid, polyacrylamide, polyamide, polyvinyl alcohol, gelatin, or finely pulverized products or emulsions of these resins There is a method of containing at the time of material molding. These fine particles and finely pulverized products preferably have a diameter of 1 μm or less.

  The peelable substrate 2 can also use flexible paper-based materials, such as thin paper, high-quality paper, Japanese paper, non-woven fabric, kraft paper, and synthetic paper. As shown in FIG. 2, these peelable substrates 2 are preferably laminated with a peelable layer 4 in order to ensure surface smoothness.

  The release layer 4 is preferably composed of a synthetic resin having flexibility and wear resistance, and further having heat resistance capable of withstanding thermocompression bonding in the transfer process. Examples of such a release layer 4 include water-soluble polyvinyl alcohol, gelatin, epoxy resin, melamine resin, phenol resin, fluorine resin, silicone resin, acrylic resin such as acrylic polyol, ester resin, urethane resin, and polyamide resin such as nylon, Cellulosic resins and the like can be exemplified. The release layer 4 was prepared by dissolving the resin in an aromatic hydrocarbon such as toluene and xylene, ketones such as methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate and methyl acetate, and alcohols such as propanol and butanol. The solution can be formed by applying and drying by various printing methods. In addition, the peeling layer 4 can also be laminated | stacked and formed on the surface of an above-described synthetic resin peelable base material.

  In addition to the form shown in FIGS. 1 and 2, as shown in FIGS. 3 and 4, a heat-sealable resin layer 5 can be further laminated on the upper surface of the electrode forming layer 3. The heat-sealable resin layer 5 is preferably formed of the same material as the above-described thermoplastic resin having heat-sealability, and the thickness of the heat-sealable resin layer 5 is about 5 μm to about 300 μm, preferably about It is about 10 μm to about 200 μm.

The coating amount of the heat-sealable resin layer 5 is about 30 g / m ² or less in terms of dry weight because it may damage the original surface characteristics when transferred to the transfer material and may peel off during sintering. Is preferred. Further, an adhesion strengthening layer (not shown) having a high adhesive strength can be formed around the heat-sealable resin layer 5 to prevent the transferred object from being peeled off from the periphery after being transferred to the transferred object. As the adhesion-strengthening layer, it is preferable to use a material having excellent adhesive strength in the above-described heat-sealable resin layer material.

  The above-described thermal transfer sheet for a solid oxide fuel cell can impart flexibility to the thermal transfer sheet itself, and therefore can be thermally transferred to a cylindrical surface or the like. There is no breakage.

  In the above description, the electrode forming layer has been described, but an electrolyte forming layer may be used instead of the electrode forming layer. The electrolyte forming layer can also be formed by the same method as the electrode forming layer. As the electrolyte forming material, those known as electrolytes for solid oxide fuel cells can be used. And oxygen ion conductive ceramic materials such as zirconia-based oxides containing scandium and yttrium can be used.

  The present invention will be further clarified by the following examples.

  60 parts by weight of NiO powder (0.01-10 μm, average particle size 1 μm) as an electrode (fuel electrode) forming electrode material is dispersed in 20 parts by weight of toluene, and this is dispersed in 20 parts by weight of a cellulose-based resin and dibutyl as a plasticizer. A paste was prepared by mixing with 6 parts by weight of phthalate. Next, the PET film is pulled out from a roll of a matted PET film (thickness 50 μm), and the paste is coated thereon by a knife coating method so as to have a dry film thickness of 50 μm, dried and wound up. A roll-shaped thermal transfer sheet was produced.

  In the obtained thermal transfer sheet, the dry film thickness error of the electrode forming layer was ± 2 μm or less in both the flow direction and the width direction.

It is a longitudinal cross-sectional view which shows one Embodiment of the thermal transfer sheet for solid oxide fuel cells which concerns on this invention. It is a longitudinal cross-sectional view which shows the change aspect of the thermal transfer sheet for solid oxide fuel cells of FIG. It is a longitudinal cross-sectional view which shows the change aspect of the thermal transfer sheet for solid oxide fuel cells of FIG. It is a longitudinal cross-sectional view which shows the change aspect of the thermal transfer sheet for solid oxide fuel cells of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal transfer sheet for solid oxide fuel cells 2 Peelable substrate 3 Electrode forming layer 4 Peeling layer 5 Heat-sealable resin layer

Claims (6)

Printing and drying a paste in which a solid oxide fuel cell electrode forming material or a solid oxide fuel cell electrolyte forming material and a binder containing a thermoplastic resin are mixed on a peelable substrate having a smooth surface. Thus, a thermal transfer sheet for a solid oxide fuel cell, wherein an electrode forming layer or an electrolyte forming layer for thermal transfer to a transfer target is formed. 2. The thermal transfer sheet for a solid oxide fuel cell according to claim 1, further comprising a heat sealable resin layer laminated on the upper surface of the electrode forming layer or the electrolyte forming layer. The thermal transfer sheet for a solid oxide fuel cell according to claim 2, wherein the binder and the heat-sealable resin layer contain the same thermoplastic resin. The thermal transfer sheet for a solid oxide fuel cell according to any one of claims 1 to 3, wherein the peelable substrate is a synthetic resin film or sheet that has been matted. The thermal transfer sheet for a solid oxide fuel cell according to any one of claims 1 to 3, wherein the release substrate has a release layer formed on the surface of the film or sheet. A laminate for a solid oxide fuel cell, wherein an electrode forming layer of the thermal transfer sheet for a solid oxide fuel cell according to any one of claims 1 to 5 is formed on a solid electrolyte. body.

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