JP2011076959A - Single cell of solid oxide fuel cell, and solid oxide fuel cell including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a single cell of a solid oxide fuel cell capable of stabilizing the fuel cell performance, and to provide a solid oxide fuel cell including the same. <P>SOLUTION: The single cell of the solid oxide fuel cell is arranged on a support substrate 11 and is provided with: an electrolyte 2 arranged on one side of the support substrate 11; a fuel electrode 3 which is arranged on the electrolyte 2 and extends in a prescribed direction; an air electrode 4 which is arranged on the electrolyte 2 and is separated from the fuel electrode 3 and extends in the same direction as the fuel electrode 3; a first current collector layer 5 which is arranged on the fuel electrode 3 and extends along the fuel electrode 3; and a second current collector layer 6 which is arranged on the air electrode 4 and extends along the air electrode 4. Each of the current collector layers 5, 6 has gas permeability. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a single cell for a solid oxide fuel cell and a solid oxide fuel cell including the same.

  A fuel cell is a cell that can directly convert chemical energy generated when fuel is oxidized into electric energy while continuously supplying fuel from the outside and exhausting combustion products. The types of fuel cells are classified according to the electrolyte, and those using a solid oxide having ionic conductivity for the electrolyte are called solid oxide fuel cells. Various types of solid oxide fuel cells have been proposed. For example, Patent Document 1 discloses an electrolyte substrate on the same surface of a solid electrolyte sheet of stabilized zirconia or perovskite oxide. The structure of a single-chamber solid oxide fuel cell in which a palladium / platinum / nickel or rhodium electrode and a gold electrode are printed and a fuel electrode (anode) and an air electrode (cathode) are formed at predetermined intervals. It is disclosed. As a single-chamber electrode material, the air electrode is composed of Ln1-xSrxCoO3-δ (where Ln is a rare earth element) doped with strontium, and the fuel electrode is composed of nickel and cerium oxide. It is stated that an oxide-containing material is used, and it is disclosed that materials used in a general two-chamber solid oxide fuel cell can be used.

Japanese Patent No. 2810977

  In the solid oxide fuel cell of Patent Document 1, the comb-shaped fuel electrode and the air electrode are arranged to mesh with each other. The adjacent batteries are connected by an interconnector. However, this interconnector is provided on the side opposite to the comb teeth of each electrode. In other words, since the electrodes are in partial contact with each electrode, there is a problem that electrons generated at each electrode are difficult to take out and the battery performance is not stable.

  The present invention has been made to solve the above problems, and provides a solid oxide fuel cell unit cell capable of stabilizing battery performance and a solid oxide fuel cell including the same. Objective.

  The present invention relates to a unit cell for a solid oxide fuel cell disposed on a support substrate, an electrolyte disposed on one surface of the support substrate, and a fuel electrode disposed on the electrolyte and extending in a predetermined direction. An air electrode disposed on the electrolyte and spaced apart from the fuel electrode and extending in the same direction as the fuel electrode; a first current collecting layer disposed on the fuel electrode and extending along the fuel electrode; A second current collecting layer disposed on the air electrode and extending along the air electrode, and each current collecting layer has gas permeability.

  According to this configuration, each electrode is formed to extend in a predetermined direction, and each current collecting layer is formed on the electrode along the electrode. Therefore, electrons can be taken out over the entire length of each electrode. As a result, battery performance can be stabilized. In addition, the electrode extended in the predetermined direction as used in the field of this invention points out what is not a point object shape like a square, for example. For example, in addition to a rectangle and a strip extending in one direction, a shape extending in multiple directions such as an L shape and a waveform may be used. Moreover, since gas permeability should just permeate | transmit gas, it may form with a porous material or what formed the through-hole.

  In the single cell, each current collecting layer can be disposed on the entire surface of the fuel electrode and the air electrode. Here, the entire surface does not necessarily refer to all surfaces of each electrode. For example, the current collecting layer is disposed at 80% or more of the length in the longitudinal direction of the surface opposite to the electrolyte in each electrode. It only has to be.

  A first solid oxide fuel cell according to the present invention includes a gas-permeable support substrate, and at least one single cell for a solid oxide fuel cell, which is disposed on the support substrate. It is equipped with.

  A second solid oxide fuel cell according to the present invention includes a first support substrate, a plurality of single cells for a solid oxide fuel cell disposed on the first support substrate, and the plurality of single cells described above. A gas permeable second support substrate in which the single cell for a solid oxide fuel cell is disposed between the first support substrate, and the first support substrate in the second support substrate; An interconnector that is disposed on the opposing surface and is connected to each of the current collecting layers and electrically connects a plurality of single cells for a solid oxide fuel cell, and the fuel electrode and the air electrode, Has gas permeability.

  According to this configuration, a plurality of the single cells described above can be connected. At this time, for example, if an interconnector is previously disposed on the second support substrate and brought into contact with the current collecting layer, a plurality of single cells can be electrically connected. In addition, since the second support substrate has gas permeability, power can be generated by supplying fuel gas and oxidant gas from the upper surface of the second support substrate. Here, the first support substrate may also have gas permeability. By carrying out like this, gas can be supplied with respect to a single cell from any direction with respect to a single cell.

  The third solid oxide fuel cell according to the present invention is disposed between a plurality of gas permeable support substrates arranged in parallel at a predetermined interval and the adjacent support substrate, Among the plurality of solid oxide fuel cell single cells described above, wherein the electrolyte is disposed on one of the support substrates, and among the adjacent support substrates, the surface is disposed on the other support substrate, and An interconnector connected to each current collecting layer and electrically connecting the plurality of solid oxide fuel cell single cells, wherein the fuel electrode, the air electrode, and each current collecting layer are gas permeable The electrolyte is densely formed.

  According to this configuration, since a plurality of single cells are arranged between a plurality of support substrates having gas permeability, power is generated by supplying fuel gas and oxidant gas in the stacking direction of the support substrates. Can do. Here, since the electrolyte is densely formed, the supplied gas does not pass through the portion where the electrolyte is disposed on the support substrate, but flows along the surface direction. Therefore, gas can be supplied to all the single cells on the support substrate. Then, the gas flows in the stacking direction of the support substrate through a portion of the support substrate where the electrolyte is not disposed. As described above, since the gas flows in a direction perpendicular to and parallel to the surface of the support substrate, the gas diffusibility can be greatly improved, and the gas is supplied uniformly to each single cell. Can do.

  According to the present invention, battery performance can be stabilized.

It is a side view of a single cell concerning a 1st embodiment of the present invention. It is a top view of FIG. It is sectional drawing of the solid oxide fuel cell which concerns on 2nd Embodiment of this invention. It is sectional drawing of the solid oxide fuel cell which concerns on 3rd Embodiment of this invention.

(First embodiment)
Hereinafter, embodiments of a single cell for a solid oxide fuel cell according to the present invention will be described with reference to the drawings. FIG. 1 is a side view of a unit cell for a solid oxide fuel cell according to this embodiment, and FIG. 2 is a plan view of FIG.

  As shown in FIGS. 1 and 2, the unit cell for a solid oxide fuel cell according to the present embodiment is disposed on a support substrate, and is in the form of a thin film disposed on a porous support substrate 11. An electrolyte 2 is provided. A rectangular fuel electrode 3 and air electrode 4 are arranged on the upper surface of the electrolyte 2 at a predetermined interval. Furthermore, first and second current collecting layers 5 and 6 are disposed on the upper surfaces of the fuel electrode 3 and the air electrode 4. The current collecting layers 5 and 6 are provided over the entire upper surface of the fuel electrode 3 or the air electrode 4. Here, the electrolyte 2 is densely formed and hardly permeates gas. On the other hand, each electrode 3 and 4 and each current collection layer 5 and 6 are formed in the porous shape which permeate | transmits gas.

  Subsequently, materials constituting the single cell will be described. The support substrate 11 is porous, and considering the gas permeability, the porosity is preferably in the range of 10 to 70% by volume, and more preferably in the range of 30 to 60% by volume. In order to satisfy such requirements, the material constituting the support substrate 11 is not particularly limited as long as it is made of an insulating material. For example, a ceramic material such as an alumina material or a silica material may be used. it can. The support substrate 11 can be formed by, for example, a pressing method in which powder is pressed and sintered, or a tape casting method. As for the tape casting method, a support sheet is formed by producing and sintering a green sheet from the above materials. Specifically, the above-mentioned materials and pore former are added, a binder, a dispersant and a plasticizer are added, and a slurry dispersed by a dispersion medium composed of an alcohol solvent such as ethanol and 2-propanol is prepared. The addition amount of the pore former is preferably 5 to 20 wt% with respect to the total weight ratio of the material of the support substrate 11. Since the added pore former burns and decomposes and disappears during sintering, voids are formed at locations where the pore former was present.

Examples of the pore-forming agent include carbon powder, thermoplastic resin powder, thermoplastic resin fiber, thermosetting resin powder, thermosetting resin fiber, natural fiber, and natural fiber derivatives. Examples of the carbon powder include carbon black, activated carbon, graphite (graphite), and amorphous carbon. The content of the metal component in the carbon powder is preferably 100 mg / kg or less, and particularly preferably contains no metal component. The thermoplastic resin powder, thermoplastic resin fiber, thermosetting resin powder or thermosetting resin fiber may be, for example, a hydrocarbon compound such as polystyrene, polymethyl methacrylate, phenol resin, epoxy Oxygen-containing organic compounds such as resins; nitrogen-containing compounds such as polyamide, melamine resin, urea resin, and polyurethane; and compounds containing atoms other than carbon atoms and hydrogen atoms, such as sulfur-containing compounds such as polysulfone. Of these, hydrocarbon compounds and oxygen-containing organic compounds are preferred in that no gas other than carbon dioxide gas is generated during combustion. Examples of natural fibers include cellulose fibers and protein fibers, and cellulose fibers include semi-artificial acetate and rayon. Examples of natural fiber derivatives include ethyl esters of natural fibers such as ethyl cellulose.
When the pore-forming agent is granular, the average particle diameter (average diameter) is preferably 0.1 to 20 μm, particularly preferably 0.5 to 10 μm, and further preferably 1 to 5 μm. If the average particle diameter of the pore former is less than 0.1 μm, the pore diameter of the pores of the support substrate 1 becomes too small, so that the slurry for forming the support substrate is difficult to impregnate, and if it exceeds 20 μm, Since the pore volume of the pores of the support substrate 11 becomes too large, the strength of the support substrate 11 tends to decrease. In the case of a granular shape, a value obtained by averaging the longest lengths among the diameters of the individual particles in the vertical direction, the horizontal direction, and the depth direction is the average particle diameter of the granular pore-forming agent.

  When the pore former is fibrous, the average fiber length is preferably 0.01 to 10 μm, particularly preferably 0.05 to 5 μm, and further preferably 0.1 to 1 μm. When the average fiber length of the pore former is less than 0.01 μm, the pore diameter of the pores of the support substrate 1 becomes too small, so that the slurry for forming the support substrate is difficult to impregnate, and when the average fiber length exceeds 10 μm. Since the pore volume of the pores of the support substrate 11 becomes too large, the strength of the support substrate 11 tends to decrease. The average fiber diameter of the pore former is not particularly limited, but is preferably 0.001 to 1 μm, particularly preferably 0.005 to 0.5 μm. In the case of a fiber, the average value of the lengths in the transverse direction of individual fibers is the average fiber length, and the longer length of the diameters of the individual fibers in the longitudinal and depth directions is averaged. The value obtained is the average fiber diameter. Of these, one or more can be used.

  The support substrate 11 produced by the above-described process is porous, and the porosity of the support substrate 11 is the volume V of the support substrate 11 in the liquid, the density ρ of the support substrate, and the weight of the support substrate 11 in the air. It was identified using the Archimedean method calculated from the thickness W or the weight W ′ of the support substrate in the liquid.

  As the material of the electrolyte 2, those known as electrolytes for solid oxide fuel cells can be used. For example, ceria oxide (GDC) doped with samarium or gadolinium, lanthanum doped with strontium or magnesium An oxygen ion conductive ceramic material such as a galide oxide, zirconia oxide (YSZ) containing scandium or yttrium can be used. The electrolyte 2 can be formed by, for example, a wet coating method. Examples of the wet coating method include a spray method, a screen printing method, and a dip coating method. In that case, the electrolyte 2 needs to be made into a paste, and is formed by adding an appropriate amount of a binder resin, an organic solvent, or the like with the above-described material as a main component. More specifically, it is preferable to add the binder resin so that the main component is 50 to 95% by weight in the mixing of the main component and the binder resin. In addition, as described above, the electrolyte 2 needs to be densely formed and difficult to permeate the gas. Therefore, the relative density is preferably 90% or more.

  As the fuel electrode 3, 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, or a noble metal (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. In addition, examples of those having a perovskite structure include lanthanum galide oxides doped with strontium and magnesium. Among the above materials, it is preferable to form the fuel electrode 3 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 may be a powder modification to nickel or a nickel modification to ceramic material. Good. Moreover, the ceramic material mentioned above can be used individually by 1 type or in mixture of 2 or more types. Moreover, the fuel electrode 3 can also be comprised using a metal catalyst alone.

As the ceramic powder material forming the air electrode 4, for example, a metal oxide made of Co, Fe, Ni, Cr, Mn or the like having a perovskite structure or the like can be used. Specifically, (Sm, Sr) CoO ₃ , (La, Sr) MnO ₃ , (La, Sr) CoO ₃ , (La, Sr) (Fe, Co) O ₃ , (La, Sr) (Fe, Co , Ni) O _{3 and the} like, and (La, Sr) (Fe, Co) O ₃ is preferable. The ceramic material mentioned above can be used individually by 1 type or in mixture of 2 or more types.

  As described above, the fuel electrode 3 and the air electrode 4 are formed of a porous material, but from the viewpoint of gas permeability, the porosity is preferably 20 to 50% by volume, and 30 to 30%. More preferably, it is 40 volume%.

  The average particle size of the powder used when the electrolyte 2, the fuel electrode 3 and the air electrode 4 are formed from a ceramic powder material is preferably 10 nm to 100 μm, more preferably 50 nm to 50 μm, and particularly preferably 100 nm to 10 μm. It is. In addition, an average particle diameter can be measured according to JISZ8901, for example. The fuel electrode 3 and the air electrode 4 are formed to have a film thickness of 5 to 100 μm, more preferably 5 to 50 μm.

  The fuel electrode 3 and the air electrode 4 can be formed by, for example, a wet coating method. Examples of the wet coating method include a spray method, a screen printing method, an ink jet method, and a dip coating method. In that case, the electrolyte 2 needs to be made into a paste, and is formed by adding an appropriate amount of a binder resin, an organic solvent, or the like with the above-described material as a main component. More specifically, it is preferable to add the binder resin so that the main component is 50 to 95% by weight in the mixing of the main component and the binder resin. The fuel electrode 3 and the air electrode 4 are formed to have a film thickness of 5 to 100 μm, preferably 5 to 50 μm. The thickness of the electrolyte 2 is preferably 1 to 100 μm, and more preferably 5 to 50 μm.

  Each of the current collecting layers 5 and 6 is made of a conductive metal or metal oxide material and is made of Pt, Au, Ag, Ni, SUS, or La (Cr, Mg) O3, (La, Ca) CrO3, (La , Sr) A lanthanum chromite material such as CrO 3, and one of these may be used alone, or two or more may be used in combination. The current collecting layers 5 and 6 are formed to have a thickness of 5 to 100 μm, and more preferably 5 to 50 μm. Each of the current collecting layers 5 and 6 can be formed by, for example, a wet coating method. Examples of the wet coating method include a spray method, a screen printing method, and a dip coating method. At that time, each of the current collecting layers 5 and 6 needs to be made into a paste, and is formed by adding an appropriate amount of a binder resin, an organic solvent, or the like with the above-described material as a main component. More specifically, it is preferable to add the binder resin so that the main component is 50 to 95% by weight in the mixing of the main component and the binder resin. In addition, as above-mentioned, although the current collection layers 5 and 6 are formed with porous, it is preferable that the porosity is 20-50 volume% from a gas-permeable viewpoint, and 30-40 More preferably, it is volume%.

  In the single cell, power generation is performed as follows. First, a mixed gas of a fuel gas composed of a hydrocarbon gas such as methane and an oxidant gas such as air is supplied to the surface of the single cell. Thereby, since the fuel electrode 3 and the air electrode 4 are in contact with the fuel gas and the oxidant gas, respectively, oxygen ion conduction through the electrolyte 2 occurs between the fuel electrode 3 and the air electrode 4 to generate power. .

As described above, according to the present embodiment, since the current collecting layers 5 and 6 are formed on the entire upper surface of the electrodes 3 and 4, electrons are extracted over the entire longitudinal direction of the electrodes 3 and 4. be able to. As a result, battery performance can be stabilized. Note that the support substrate 11 is not porous, and a dense substrate can also be used.
(Second Embodiment)
Next, an embodiment of a solid oxide fuel cell in which a plurality of the single cells are connected will be described. FIG. 3 is a cross-sectional view of the solid oxide fuel cell in the present embodiment.

  As shown in FIG. 3, this fuel cell uses a plurality of single cells shown in the first embodiment. That is, a plurality of single cells are arranged between the pair of porous support substrates 11 and 12 described above, and these are electrically connected by the interconnector 8. More specifically, three single cells, that is, first, second, and third single cells C1 to C3 are arranged on the upper surface of the first support substrate 11 at a predetermined interval. On the other hand, four interconnectors 8 are disposed on the lower surface of the second support substrate, and each interconnector 8 is in contact with the upper surfaces of the current collecting layers 5 and 6 of the single cells C1 to C3. Each interconnector 8 is formed in a band shape in plan view, and connects the three single cells C1 to C3 described above in series. For example, the second current collecting layer 6 of the first single cell C1 and the first current collecting layer 5 of the second single cell C2 are connected by the interconnector 8.

  This fuel cell can be manufactured, for example, as follows. First, an electrolyte paste is applied on the first support substrate 11, dried, and then sintered to form the electrolyte 2. Next, a fuel electrode pace is applied on the electrolyte 2, dried, and then sintered to form the fuel electrode 3. Similarly, an air electrode paste is applied on the electrolyte 2, dried, and then sintered to form the air electrode 4. Further, the current collecting layer paste is applied onto the fuel electrode 3 and the air electrode 4, dried and sintered. Thus, the first and second current collecting layers 5 and 6 are formed. On the other hand, an interconnector paste is applied to the lower surface of the second support substrate 12, dried and sintered to form the interconnector 8. In addition, the material which forms an interconnector is the same as the current collection layers 5 and 6 mentioned above. Subsequently, the second support substrate 12 on which the interconnector 8 is formed is disposed on the upper surfaces of the single cells C1 to C3. At this time, the interconnector 8 is positioned so that the three single cells C1 to C3 are connected.

As described above, according to the present embodiment, the plurality of single cells C1 to C3 can be connected in series by the second support substrate 12 on which the interconnector 8 is disposed. In addition, since it is not necessary to form the interconnector directly on the single cell, if the arrangement of the interconnector 8 on the second support substrate 12 is changed, a desired connection such as series or parallel becomes possible. The power generation method is the same as that in the first embodiment. However, since the second support substrate 12 is formed of a porous material, the mixed gas permeates the second support substrate 12 and each single cell C1. ˜C3 electrodes 3 and 4 are supplied. Further, since the first support substrate 11 is also porous and has gas permeability, the mixed gas can be supplied to the single cells C1 to C3 from any direction.
(Third embodiment)
Next, an embodiment of a fuel cell in which the fuel cells of the second embodiment are stacked in the vertical direction will be described. FIG. 4 is a cross-sectional view of the solid oxide fuel cell in the present embodiment.

  As shown in FIG. 4, this fuel cell is a stack of the fuel cells of the second embodiment in three stages. That is, four support substrates are arranged in parallel at a predetermined interval, and three single cells are arranged therebetween. Here, the four support substrates are referred to as first, second, third, and fourth support substrates 11 to 14 from the bottom of FIG.

  If it demonstrates in detail, the electrolyte 2 of each single cell will be arrange | positioned on the upper surface of the 1st-3rd support substrates 11-13. On the other hand, the interconnector 8 is disposed on the lower surfaces of the second to fourth support substrates 12 to 14, and the single cells on the first to third support substrates 11 to 13 are connected in series. Further, the four support substrates 11 to 14 are sandwiched from the left-right direction by the current collector plate 9 arranged in the left-right direction in FIG. Each current collector plate 9 is formed with four grooves 91 into which end portions of the respective support substrates 11 to 14 are inserted, whereby the support substrates 11 to 14 and the current collector plate 9 are connected.

  The current collector plate 9 can be made of a conductive metal such as Fe, Ti, Cr, Cu, Ni, Ag, Au, or Pt. One type may be used alone, or two or more types may be mixed. May be. For example, stainless steel heat-resistant materials can be used, and specifically, austenitic stainless steel, ferritic stainless steel, nickel-based heat-resistant alloys such as Inconel and Hastelloy, and the like can be used. In addition, a conductive metal oxide can be used, and for example, a lanthanum chromite material such as La (Cr, Mg) O3, (La, Ca) CrO3, (La, Sr) CrO3 can be used. The thickness of the current collector plate is preferably 200 to 5000 μm.

  In the single cell, power generation is performed as follows. First, a mixed gas of a fuel gas composed of a hydrocarbon-based gas such as methane and an oxidant gas such as air is supplied from the upper side to the lower side of the fourth support substrate 14. The mixed gas (arrow in FIG. 4) permeates through each of the support substrates 11 to 14 and contacts the single cells on the first to third support substrates 11 to 13 while flowing downward. Thereby, since the fuel electrode 3 and the air electrode 4 are in contact with the fuel gas and the oxidant gas, respectively, oxygen ion conduction through the electrolyte 2 occurs between the fuel electrode 3 and the air electrode 4 to generate power. . In addition, the arrow shown in FIG. 4 has shown the flow of mixed gas.

  As described above, according to the present embodiment, since a plurality of single cells are arranged between four support substrates having gas permeability, the mixed gas is supplied in the stacking direction of the support substrates 11 to 14. Power generation. Here, since the electrolyte 2 is densely formed, the supplied gas does not pass through the portion where the electrolyte 2 is disposed in the first to third support substrates 11 to 13 but flows along the surface direction. To go. Therefore, the mixed gas can be supplied to all the single cells on the first to third support substrates 11 to 13. Then, the mixed gas passes through the portion where the electrolyte 2 is not disposed in the first to third support substrates 11 to 13 and flows in the stacking direction of the support substrates. Accordingly, since the mixed gas flows in a direction perpendicular to and parallel to the surfaces of the first to third support substrates 11 to 13, the gas diffusibility can be greatly improved, and can be uniformly distributed to each single cell. Gas can be supplied.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the number of single cells and the number of support substrates can be changed as appropriate. Moreover, in each single cell, the shape of the electrode is not particularly limited, and may be a shape extending in a predetermined direction in addition to a rectangle, and may be arranged so that both electrodes face each other. Further, the current collecting layer does not necessarily have to be disposed on the entire upper surface of the electrode, but is preferably formed at least along the direction in which the electrode extends. In particular, if the current collecting layer is disposed at 80% or more in the longitudinal direction of the upper surface of the electrode, it becomes easier to take out electrons during power generation. Further, in the third embodiment, a casing shape in which gas inlets and outlets are provided in the upper and lower portions of the stack may be taken. In the first and second embodiments, the support substrate 11 disposed on the lower side of the single cell may be dense gas impermeable.

  Examples of the present invention will be described below. However, the present invention is not limited to the following examples. First, the evaluation test of the battery performance was performed about the single cell similar to 1st Embodiment. Here, together with Example 1 similar to the first embodiment, the evaluation test of Comparative Example 1 in which the current collecting layer is disposed adjacent to the electrode in parallel and Comparative Example 2 in which the Au mesh is used as the current collecting layer was performed. First, production methods of Examples and Comparative Examples will be described. In the following description, examples and comparative examples other than the current collecting layer are produced by the same material and manufacturing method.

  First, a support substrate is formed by a tape casting method. Regarding the tape casting method, a support substrate is formed by producing and sintering a green sheet with the support substrate material described above. Specifically, the above-mentioned materials and pore former are added, a binder, a dispersant and a plasticizer are added, and a slurry dispersed by a dispersion medium composed of an alcohol solvent such as ethanol and 2-propanol is prepared. The amount of pore-forming agent added is preferably 5 to 20 wt% with respect to the total weight ratio of the support substrate material. Since the added pore former burns and decomposes and disappears during sintering, voids are formed at locations where the pore former was present. Regarding the blending ratio, the blending ratio of the main component and the pore-forming agent was adjusted so that the porosity after firing was 20 to 70% by volume. The thickness of the support substrate was adjusted to 0.8 mm after sintering.

The fuel electrode, the electrolyte, the air electrode, and the current collecting layer were made of NiO-GDC, GDC, LSCF, and gold, respectively, and paste was prepared by adding appropriate amounts of a binder resin, an organic solvent, and the like. More specifically, it is preferable to add a binder resin or the like so that the main component is 50 to 95% by weight in the mixing of the main component and the binder resin. These are added and kneaded to prepare a fuel electrode paste, an electrolyte paste, an air electrode paste, and a current collecting layer paste. The viscosity of each paste is preferably 10 ³ to 10 ⁶ mPa · s so as to be compatible with the screen printing method. In addition, the current collection layer which produces a paste here is used for Example 1 and Comparative Example 1.

  Next, the electrolyte paste was printed on the support substrate prepared above by screen printing so that the thickness was 50 μm and the sides were 8 mm and 8 mm squares. After drying at 130 ° C. for 15 minutes, sintering was performed at 1700 ° C. for 10 hours to form an electrolyte.

  Next, the fuel electrode paste was printed on the electrolyte by screen printing so that the thickness after application was 50 μm, the electrode width was 700 μm, and the electrode length was 8 mm. And after drying at 130 degreeC for 15 minutes, it sintered at 1450 degreeC for 10 hours, and formed the fuel electrode. Further, the air electrode paste was printed by screen printing at a location where the distance from the fuel electrode was 500 μm so that the thickness after application was 50 μm, the electrode width was 700 μm, and the electrode length was 8 mm. And after making it dry at 130 degreeC for 15 minute (s), it sintered at 1200 degreeC for 1 hour, and formed the air electrode.

  Subsequently, for Example 1, the current collector layer paste was printed on the fuel electrode by screen printing so that the thickness after application was 50 μm, the current collector layer width was 700 μm, and the current collector layer length was 8 mm. And after drying for 15 minutes at 130 degreeC, it sintered at 1200 degreeC for 1 hour. Subsequently, the current collector layer paste was printed on the air electrode by screen printing so that the thickness was 50 μm, the current collector layer width was 700 μm, and the current collector layer length was 8 mm. And after drying for 15 minutes at 130 degreeC, it sintered at 1000 degreeC for 1 hour.

  In Comparative Example 1, a current collecting layer (width 700 μm, length 8 mm) was formed so as to be adjacent to one side surface extending in the longitudinal direction of each electrode. At this time, the current collecting layer is not in contact with the upper surface of each electrode, and is in contact only on the side surface. Except for the formation position, it is manufactured by the same method as in Example 1. In Comparative Example 2, a mesh made of Au (100 mesh, line width 0.07 mm, 6 mm × 3 mm) was disposed on the upper surface of each electrode. Thus, Example 1 and Comparative Examples 1 and 2 were completed.

Subsequently, power generation is performed in the manufactured Example 1 and Comparative Examples 1 and 2. The operating temperature was 700 ° C., and a mixed gas of methane and air was supplied from above each single cell. The total gas flow rate is 500 ml / min and the concentration of CH ₄ is 20%. And the cell voltage and the impedance value were measured. The results are as follows.

  First, in Comparative Example 2 using Au mesh as the current collecting layer, the performance was remarkably low. Further, in Comparative Example 1 in which the current collecting layer is disposed adjacent to the electrode in parallel, the electrode resistance is remarkably increased and includes the contact pressure of the current collecting layer. On the other hand, in Example 1 in which the current collecting layer was laminated on the electrode, the current collecting layer was formed over the entire surface of the electrode, so that the electrode resistance was reduced and a stable cell performance was obtained. It was.

Then, the fuel cell shown in 2nd Embodiment was produced, and the evaluation test of the cell performance was done. Here, two types of single cells were produced and placed between a pair of support substrates. In addition, four types of support substrates having different porosities were used.
(1) Support substrate A square support substrate made of alumina having a side of 10 mm and a thickness of 800 μm was used. Also, four types with porosity of 20, 30, 60, and 70% by volume were prepared.
(2) as a single cell electrolyte, area 0.27 cm ^2, were prepared two kinds of 0.45 cm ^2. The material was mainly composed of GDC. In addition, a fuel electrode mainly composed of NiO-GDC and an air electrode mainly composed of LSCF were formed. The area of each electrode was 0.063 cm ² . The distance between the electrodes was 500 μm. The detailed creation method is the same as that in the first embodiment. Moreover, the interconnector was formed in the lower surface of the 2nd support substrate, as shown in FIG. That is, after the interconnector paste is applied, the thickness is 50 μm, the width is 2000 μm, and the length is 9000 μm. After drying at 130 ° C. for 15 minutes, sintering was performed at 1000 ° C. for 1 hour.

  The eight types of batteries thus formed were subjected to power generation at an operating temperature of 700 ° C. At this time, the cell voltage was measured with a total gas flow rate of 500 ml / min and a methane gas concentration of 20%. The results are as follows.

From the above results, it was found that the higher the porosity and the lower the electrolyte area, the higher the performance. When the porosity volume was 60% and the electrolyte area was 0.27 cm ^2, the performance was highest and the gas diffusivity was improved, and the cell voltage was confirmed to be stable. In the support substrate having a porosity of 70% by volume, the substrate strength was reduced due to the high porosity, and cell cracking was confirmed by the internal stress difference between the support substrate and the electrolyte.

   In addition, the performance at a methane concentration of 30% was also evaluated. For example, a stable cell voltage of 0.58 V was confirmed even with a support substrate having a porosity of 20% by volume. When a support substrate having a porosity of 70% by volume was used and performance was evaluated at an operating temperature of 600 ° C., a stable cell voltage of 0.52 V was confirmed. Therefore, it can be used depending on conditions.

11 to 14 Support substrate 2 Electrolyte 3 Fuel electrode 4 Air electrode 5 First current collecting layer 6 Second current collecting layer 8 Interconnector

Claims (6)

A single cell for a solid oxide fuel cell disposed on a support substrate,
An electrolyte disposed on one side of the support substrate;
A fuel electrode disposed on the electrolyte and extending in a predetermined direction;
An air electrode disposed on the electrolyte, spaced apart from the fuel electrode and extending in the same direction as the fuel electrode;
A first current collecting layer disposed on the fuel electrode and extending along the fuel electrode;
A second current collecting layer disposed on the air electrode and extending along the air electrode;
With
Each of the current collecting layers has gas permeability and is a single cell for a solid oxide fuel cell.   The single cell for a solid oxide fuel cell according to claim 1, wherein each of the current collecting layers is disposed on the entire surface of the fuel electrode and the air electrode. A support substrate having gas permeability;
At least one single cell for a solid oxide fuel cell according to claim 1 or 2, disposed on the support substrate;
A solid oxide fuel cell. A first support substrate;
A plurality of solid oxide fuel cell single cells according to claim 1 or 2, disposed on the first support substrate;
A gas permeable second support substrate in which the single cell for a solid oxide fuel cell is disposed between the first support substrate and the first support substrate;
The second support substrate is disposed on a surface facing the first support substrate, is connected to each of the current collecting layers, and electrically connects the plurality of solid oxide fuel cell single cells. An interconnector;
With
The fuel electrode and the air electrode are gas permeable solid oxide fuel cells.   The solid oxide fuel cell according to claim 4, wherein the first support substrate has gas permeability. A plurality of gas-permeable support substrates arranged in parallel at predetermined intervals;
A plurality of unit cells for a solid oxide fuel cell according to claim 1 or 2, wherein the single cell is disposed between the adjacent support substrates, and the electrolyte is disposed on one of the support substrates.
An interconnector that is disposed on the surface of the other support substrate among the adjacent support substrates and is connected to each of the current collecting layers to electrically connect the plurality of solid oxide fuel cell single cells. When,
With
The fuel electrode, the air electrode, and each current collecting layer have gas permeability,
A solid oxide fuel cell in which the electrolyte is densely formed.

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