JP2017157476A - Fuel battery single cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery single cell which can be operated stably for a long time with a high output.SOLUTION: A fuel battery single cell 1 comprises: an anode 2; at least one current collecting part 3; a porous support body 4; a solid electrolyte layer 5; and a cathode 6. The current collecting part 3 protrudes from one face of the anode 2. The support body 4 is disposed on the side of the one face of the anode 2, and covers the one face of the anode 2 from which the current collecting part 3 protrudes. The solid electrolyte layer 5 is disposed on the side of the other face of the anode 2. The cathode 6 is disposed on a side of the solid electrolyte layer 5 opposite to the side where the anode 2 is located. It is preferred that a cavity 32 covers a surface 31 of the current collecting part 3, except a face 30 where the current collecting part connects to the anode 2.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fuel cell single cell.

  Conventionally, a solid electrolyte type fuel cell single cell using a solid electrolyte as an electrolyte is known.

  For example, in the prior patent document 1, a porous plate-shaped metal substrate, a current collecting member installed so as to partially protrude from one surface of the metal substrate, and a metal substrate so as to cover the current collecting member are disclosed. An anode disposed on one side, a solid electrolyte layer disposed on the anode, and an air electrode disposed on the solid electrolyte layer, wherein the current collector protrudes beyond the layer thickness of the anode. A single fuel cell is disclosed.

Japanese Patent No. 5564862

  However, in the conventional fuel cell single cell, since the current collecting member penetrates the anode, the number of reaction points in the anode is reduced and it is difficult to improve the output.

  In addition, by controlling the pore diameter in the anode and inclining the pore diameter from the solid electrolyte layer side toward the opposite side, the reaction function and the diffusion function are separated to ensure the reaction point There is also a technique to do. However, in the fuel cell single cell having the anode having such a configuration, as the operation time becomes longer, the conductive material whose shape is changed in the anode by the oxidation-reduction reaction is easily absorbed by the layer having a large pore diameter. As a result, the electron conduction path in the anode is interrupted, and it is difficult to operate stably for a long time.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a fuel cell single cell that can be stably operated for a long time with high output.

One aspect of the present invention comprises an anode (2),
At least one current collector (3) protruding from one side of the anode;
A porous support (4) disposed on one side of the anode and covering one side of the anode from which the current collector projects;
A solid electrolyte layer (5) disposed on the other side of the anode;
A fuel cell single cell (1) having a cathode (6) disposed on the opposite side to the anode side in the solid electrolyte layer.

  In the fuel cell single cell, the current collector protrudes from one surface of the anode. And the one surface of the anode from which the current collector protrudes is covered with a support. In the fuel cell unit cell, since the current collector is formed outside the anode, it is not necessary to reduce the reaction field in the anode. Therefore, the fuel cell single cell can secure a sufficient reaction field in the anode. Therefore, the fuel cell single cell can take out the electricity generated in the reaction field through the current collector with low loss, and can improve the output. In the fuel cell single cell, the current collector formed on one surface of the anode functions as an electronic conduction path of the anode. Therefore, the fuel cell single cell can suppress the interruption of the electronic conduction path on the anode side, and can be stably operated for a long time.

  In addition, the code | symbol in the parenthesis described in the means to solve a claim and a subject shows the correspondence with the specific means as described in embodiment mentioned later, and limits the technical scope of this invention. It is not a thing.

1 is a perspective view schematically showing a single fuel cell according to Embodiment 1. FIG. It is sectional drawing which showed typically the II-II line cross section in FIG. It is explanatory drawing which expanded and showed typically a part of sectional drawing of FIG. It is sectional drawing which showed the IV-IV sectional view typically in FIG. FIG. 5 is an explanatory diagram schematically showing an enlarged part of the cross-sectional view of FIG. 4. It is explanatory drawing for demonstrating the relationship between the ratio of the electroconductive material which exists in the interface of an anode and a current collection part, and the ratio of the electroconductive material which exists in an anode inside. It is explanatory drawing for demonstrating the calculation method of the effective area rate of a current collection part. 6 is a perspective view schematically showing a single fuel cell according to Embodiment 2. FIG. It is sectional drawing which showed typically the IX-IX sectional view in FIG.

(Embodiment 1)
The fuel cell single cell of Embodiment 1 is demonstrated using FIGS. As illustrated in FIGS. 1 to 7, the fuel cell single cell 1 of the present embodiment includes an anode 2, a current collector 3, a support 4, a solid electrolyte layer 5, and a cathode 6. ing. The fuel cell using solid oxide ceramics as the solid electrolyte of the solid electrolyte layer 3 is referred to as a solid oxide fuel cell (SOFC). The fuel cell single cell 1 can have a flat battery structure. In each drawing, an example in which the outer shape of the fuel cell single cell 1 is a square shape is shown.

  The anode 2 is usually porous and includes pores 21 as illustrated in FIGS. 3 and 5. Specifically, the anode 2 can be configured to include a conductive material and a solid electrolyte material. In this case, the conductive material is a material constituting an electron conductive path in the anode 2. On the other hand, the solid electrolyte material becomes a skeletal material that forms an ionic conduction path in the anode 2. Examples of the conductive material used for the anode 2 include Ni and Ni alloy. Examples of the solid electrolyte material used for the anode 2 include zirconium oxide-based oxides such as yttria stabilized zirconia (YSZ) and scandia stabilized zirconia (ScSZ). In the present embodiment, specifically, a mixture of Ni and yttria-stabilized zirconia can be used as the material of the anode 2.

  The thickness of the anode 2 is preferably 10 μm or more, more preferably 15 μm or more, from the viewpoints of reaction sustainability, handleability, workability, and the like. The thickness of the anode 2 is preferably 30 μm or less, more preferably 25 μm or less, from the viewpoint of reducing electrode reaction resistance.

  The current collector 3 protrudes from one surface of the anode 2. The anode 2 can be configured, for example, as a flat layer, and the current collector 3 specifically projects from one surface of the layered anode 2 on the support 4 side. A part of the surface of the current collector 3 is connected to one surface of the anode 2.

  There may be at least one current collector 3. In each figure, the example in which the fuel cell single cell 1 has the some current collection part 3 is shown. For example, each current collector 3 can be configured to extend linearly along one surface of the anode 2 and can be arranged in a state of being separated from each other. According to this configuration, each current collector 3 provides a single fuel cell 1 that can easily collect current uniformly in the in-plane direction of the anode 2. Each figure shows an example in which at least one end of each current collector 3 extending in a straight line is exposed on the cell end face so that electricity on the anode 2 side can be taken out at the cell end face. ing.

  Specifically, the current collector 3 can be configured to include a conductive material. Examples of the conductive material used for the current collector 3 include Ni and Ni alloy. In the present embodiment, specifically, Ni can be used as the conductive material of the current collector 3.

  When both the current collector 3 and the anode 2 contain a conductive material, the ratio of the conductive material present at the interface 23 between the current collector 3 and the anode 2 is the ratio of the conductive material present inside the anode 2. It can be set as the structure larger than a ratio. According to this configuration, the electron conduction path by the current collector 3 is ensured, the interruption of the electron conduction path on the anode 2 side can be easily suppressed, and the fuel cell unit cell 1 that can be stably operated for a long time can be easily obtained. Become. In addition, the magnitude relationship of each said ratio can be grasped | ascertained as follows. As illustrated in FIG. 6, by using a scanning electron microscope, a cross-sectional observation (× 1000 times) of a region A at the interface 23 between the current collector 3 and the anode 2 and a region B inside the anode 2 were performed. An arbitrary 50 μm width is analyzed by EDX measurement. By comparing the obtained line analysis patterns, it is possible to obtain the magnitude relationship between the above-mentioned ratios.

Specifically, the difference between the linear thermal expansion coefficient of the conductive material included in the current collector 3 and the linear thermal expansion coefficient of the conductive material included in the anode 2 is 1 × 10 ⁻⁶ / K or less. Can do. In this case, the current collector 3 is difficult to peel off from the anode 2 due to expansion and contraction due to heat during long-term operation, and it becomes easier to obtain a single fuel cell 1 that can be stably operated for a long time.

The difference in the coefficient of linear thermal expansion is preferably 0.9 × 10 ⁻⁶ / K or less, more preferably 0.8 × 10 ⁻⁶ / K, from the viewpoint of adhesion between the current collector 3 and the anode 2. Hereinafter, it is more preferably 0.7 × 10 ⁻⁶ / K or less, still more preferably 0.6 × 10 ⁻⁶ / K or less, and still more preferably 0.5 × 10 ⁻⁶ / K or less. it can. The difference in the coefficient of linear thermal expansion is basically measured according to JIS R1618: 2002 “Method of measuring thermal expansion by thermomechanical analysis of fine ceramics”. Specifically, a sample made of the same material as the conductive material included in the current collector 3 and a sample made of the same material as the conductive material included in the anode 2 are prepared. Each sample is set in a full expansion thermomechanical analyzer, and the temperature is increased at a rate of temperature increase of 10 ° C./min. By the time T rises from T ₀ (= 100 ° C.) to T ₁ (= 700 ° C.), each sample expands from length L ₀ to L ₁ . Each line thermal expansion coefficient at this time (/ K), respectively calculated from the calculation formula _{(dL / dT) T = T1} / L 0. _{However, (dL / dT) T =} T1 , the temperature T is the slope of the long curve at the time of _{T 1.} The difference in linear thermal expansion coefficient is calculated from the absolute value of the difference in linear thermal expansion coefficient of each sample obtained.

  Specifically, the current collector 3 can include a continuous portion continuously connected along one surface of the anode 2. According to this configuration, it is possible to obtain the fuel cell single cell 1 that can easily take out electricity along one surface of the anode 2. In addition, the current collection part 3 may contain the discontinuous part in part within the range which can be drive | operated stably for a long time. This is because, in the discontinuous portion, adjacent continuous portions are electrically connected to each other through the conductive material in the anode 2, so that the electronic conductive path is not interrupted.

  For example, as shown in each drawing, the form of the continuous portion may be configured such that a plurality of hemispherical portions are connected along one surface of the anode 2. In such a continuous part where a plurality of hemispherical parts are connected, the material forming the current collecting part 3 is repeatedly changed in shape by operating the fuel cell single cell 1 for a long time, and becomes a stable hemispherical shape. It can be formed by utilizing the phenomenon of trying.

  Specifically, the ratio of the length of the continuous portion included in the current collector 3 is larger than the ratio of the connecting length of the conductive material in an arbitrary plane in the anode 2 parallel to one surface of the anode 2. It can be. This configuration is confirmed by observing a cross section of the fuel cell single cell 1 and comparing the ratio of the length of the continuous portion to the observation length and the ratio of the connection length of the conductive material to the observation length. be able to.

  The protruding amount of the current collector 3 is preferably 1 μm or more, more preferably 3 μm or more, and further preferably 5 μm or more from the viewpoint of electrical conductivity and the like. The protruding amount of the current collector 3 is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less from the viewpoint of cell strength and the like. Note that the amount of protrusion of the current collector 3 is measured by cross-sectional observation (× 1000 times) of the interface 23 between the current collector 3 and the anode 2 using a scanning electron microscope. It is an average value of each measured value when the protruding length is measured.

  The width of the current collector 3 is preferably 20 μm or more, more preferably 50 μm or more, and even more preferably 100 μm or more, from the viewpoint of improving current collection, ease of formation, and the like. The width of the current collector 3 is preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably 200 μm or less from the viewpoint of cell strength and the like. Further, the pitch of the current collector 3 is preferably 50 μm or more, more preferably 100 μm or more, and further preferably 400 μm or more, from the viewpoint of cell strength, ease of formation, and the like. The pitch of the current collector 3 is preferably 5000 μm or less, more preferably 2000 μm or less, and even more preferably 1000 μm or less, from the viewpoint of improving current collection.

  The surface 31 excluding the surface 30 connected to the anode 2 in the current collector 3 can be configured to be covered with a gap 32. According to this configuration, the air gap 32 is present along the current collector 3 disposed on one surface of the anode 2. Therefore, the air gap 32 can function as a diffusion flow path when diffusing the fuel gas supplied to the anode 2 in the in-plane direction. In addition, the air gap 32 can be caused to function as a discharge channel for discharging water vapor generated at the anode 2 by the power generation reaction. Further, since the current collector 3 is covered with the gap 32, it becomes difficult for the current collector 3 to contact the large pores included in the support 4. Therefore, although the change of the current collection part 3 by oxidation-reduction reaction arises, it can prevent that the electroconductive material of the current collection part 3 moves to the support body 4, and can stabilize electrical conductivity. The gap 32 can be formed as follows, for example. A current collector forming material is formed from an oxide of a conductive material used for the current collector 3. At this time, the current collector forming material has a volume obtained by combining the volume of the current collector 3 and the volume of the gap 32. By reducing the formed current collector forming material in a reducing atmosphere, an oxide of a conductive material is used as a conductive material, and a void 32 covering the current collector 3 can be formed by volume contraction generated at this time.

  The air gap 32 exists between the current collector 3 and the support 4. As illustrated in each drawing, a part of the anode 2 may be exposed in the gap 32. In addition, a part 33 of the material forming the current collector 3 may be attached to the wall surface on the support 4 side in the gap 32.

  The support 4 is disposed on one side of the anode 2 and covers one side of the anode 2 from which the current collector 3 protrudes. The support 4 is porous and includes pores 41 as illustrated in FIGS. 3 and 5. However, from the viewpoint of diffusing the fuel gas supplied to the anode 2, the porosity of the support 4 is sufficiently larger than the porosity of the anode 2. That is, the anode 2 is formed more densely than the support 4.

  Examples of the material of the support 4 include zirconia, magnesia, and alumina. Examples of zirconia include zirconium oxide-based oxides such as yttria-stabilized zirconia and scandia-stabilized zirconia. In this case, it becomes easy to reduce the thermal expansion difference from other materials of the cell, and it becomes easy to obtain a fuel cell single cell with less warpage. In the present embodiment, specifically, yttria-stabilized zirconia can be used as the material of the support 4. In addition, since the support body 4 does not need to have electroconductivity, it does not need to contain an electroconductive material, but can also contain an electroconductive material.

  The thickness of the support 4 is preferably 100 μm or more, more preferably 200 μm or more, and more preferably 300 μm or more from the viewpoint of securing cell strength and the like. The thickness of the support 4 is preferably 800 μm or less, more preferably 700 μm or less, from the viewpoint of improving gas diffusibility.

  The solid electrolyte layer 5 is disposed on the other surface side of the anode 2.

  As a material for the solid electrolyte layer 5, zirconium oxide-based oxides such as yttria-stabilized zirconia and scandia-stabilized zirconia can be suitably used from the viewpoint of excellent strength and thermal stability. The material of the solid electrolyte layer 5 is preferably yttria-stabilized zirconia from the viewpoints of ion conductivity, mechanical stability, compatibility with other materials, and chemical stability from an air atmosphere to a fuel gas atmosphere. is there. In the present embodiment, specifically, yttria-stabilized zirconia can be used as the material of the solid electrolyte layer 3.

  The thickness of the solid electrolyte layer 5 is preferably 3 to 20 μm, more preferably 4 to 15 μm, and still more preferably 5 to 10 μm, from the viewpoint of reducing ohmic resistance.

  The cathode 6 is disposed on the opposite side of the solid electrolyte layer 5 from the anode 2 side. In the present embodiment, the outer shape of the cathode 6 is formed smaller than the outer shape of the anode 2. In each figure, the outer shapes of the support 4, the anode 2, the solid electrolyte layer 5, and the intermediate layer 7 (described later) are all the same size.

Examples of the material of the cathode 6 include transition metal perovskite oxides. The transition metal perovskite oxide, specifically, for _{example, La x Sr 1-x CoO} 3 based _{oxide, La x Sr 1-x Co} y Fe 1-y O 3 based oxide, _Sm x Sr ₁ Examples include _-x CoO ₃ oxides (wherein 0 ≦ x ≦ 1, 0 ≦ y ≦ 1). These can be used alone or in combination of two or more. In the present embodiment, specifically, La _x Sr _1-x Co _y Fe _1-y O ₃ -based oxide (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) is used as the material of the cathode 6. it can.

  The thickness of the cathode 6 is preferably 20 to 100 μm, more preferably 30 to 80 μm, from the viewpoints of gas diffusibility, electrode reaction resistance, current collection, and the like.

  The fuel cell unit cell 1 can further include an intermediate layer 7 between the solid electrolyte layer 5 and the cathode 6 as illustrated in each drawing. The intermediate layer 7 is a layer mainly for suppressing the reaction between the solid electrolyte layer material and the cathode material.

Examples of the material of the intermediate layer 7 include CeO ₂ or CeO ₂ doped with one or more elements selected from Gd, Sm, Y, La, Nd, Yb, Ca, and Ho. Examples thereof include cerium oxide-based oxides such as ceria-based solid solutions. These can be used alone or in combination of two or more. In the present embodiment, specifically, a ceria-based solid solution in which CeO ₂ is doped with Gd can be used as the material of the intermediate layer 7.

  In addition, the thickness of the intermediate layer 7 is preferably 1 to 20 μm, more preferably 2 to 5 μm, from the viewpoints of reducing ohmic resistance and suppressing element diffusion from the cathode.

  In this embodiment, the fuel cell single cell 1 includes the support 4, the anode 2, the solid electrolyte layer 5, the intermediate layer 7, and the cathode 6 that are stacked in this order and joined to each other.

  In the single fuel cell 1, the effective area ratio of the current collector 3 with respect to the effective power generation area of the cell can be in the range of 3% to 30%. In this case, the current collection efficiency on the anode 2 side by the current collector 3 is good, the bondability between the support 4 and the anode 2 is high, and the separation between the support 4 and the anode 2 is easy to suppress. A single cell 1 is obtained. The effective area ratio of the current collector 3 is preferably 3% or more, more preferably 5% or more, still more preferably 7% or more, and even more preferably 10% or more, from the viewpoint of improving the current collection efficiency. Can do. The effective area ratio of the current collector 3 is preferably 25% or less, more preferably 20% or less, from the viewpoint of ensuring the bonding portion between the support 4 and the anode 2 and ensuring the void 32, etc. More preferably, it is 18% or less, More preferably, it can be 15% or less.

  The effective area ratio of the current collector 3 will be described with reference to FIG. FIG. 7 shows the positional relationship between the cathode 6, the anode 2, and the current collector 6 when the fuel cell single cell 1 is viewed from the cathode 6 side. The power generation effective area of the cell means an area of a portion where three layers of anode 2 / solid electrolyte layer 5 / cathode 6 are laminated together. In the present embodiment, the anode 2 and the solid electrolyte layer 5 have the same area, and the area of the cathode 6 is smaller than the area of the anode 2. Therefore, in this embodiment, the power generation effective area of the cell coincides with the area of the cathode 6 shown in FIG. On the other hand, the effective area of the current collector 3 refers to the area of the portion where the current collector 3 is formed within the effective power generation area of the cell. In the present embodiment, the total area of the current collectors 3 arranged within the area of the cathode 6 (hatched portion in FIG. 7) is the effective area of the current collector 3. The effective area ratio (%) of the current collector 3 can be calculated from the equation 100 × effective area of the current collector 3 / power generation effective area of the cell.

  In the single fuel cell 1, the current collector 3 projects from one surface of the anode 2. Then, one surface of the anode 2 from which the current collector 3 protrudes is covered with the support 4. In the fuel cell single cell 1, since the current collector 3 is formed outside the anode 2, it is not necessary to reduce the reaction field in the anode 2. Therefore, the fuel cell single cell 1 can secure a sufficient reaction field in the anode 2. Therefore, the fuel cell single cell 1 can take out the electricity generated in the reaction field through the current collector 3 with low loss, and can improve the output. In the single fuel cell 1, the current collector 3 formed on one surface of the anode 2 functions as an electronic conduction path of the anode 2. Therefore, the fuel cell single cell 1 can suppress the interruption of the electronic conduction path on the anode 2 side, and can be stably operated for a long time.

(Embodiment 2)
The fuel cell single cell of Embodiment 2 is demonstrated using FIG. 8 and FIG. Of the reference numerals used in the second and subsequent embodiments, the same reference numerals as those used in the above-described embodiments represent the same components as those in the above-described embodiments unless otherwise indicated.

  As illustrated in FIGS. 8 and 9, the fuel cell single cell 1 of the present embodiment has end face electrodes 8 that are electrically connected to the current collectors 3 on at least one end face of the cell. Other configurations are the same as those of the first embodiment.

  Since the single fuel cell 1 has the end face electrode 8 on at least one end face of the cell, the electricity collected by each current collector 3 can be taken out from the end face electrode 8 collectively. Therefore, according to the fuel cell single cell 1, the electricity extraction property at the cell end face is excellent. Further, since the fuel cell single cell 1 can connect the electricity collected by the current collector 3 to the outside via the end face electrode 8, the electric power in the fuel cell stack having a plurality of fuel cell single cells 1 can be obtained. This is advantageous for simplifying a simple connection structure.

  In the present embodiment, specifically, the outer shape of the fuel cell single cell 1 is rectangular. Therefore, there are six cell end faces. In each figure, an example in which the end face electrode 8 is formed on one of the six cell end faces is shown. At the cell end surface where the end surface electrode 8 is formed, the end of each current collector 3 is exposed, and the end of each current collector 3 is electrically connected to the end surface electrode 8. Thereby, it is possible to reliably receive electricity from each current collector 3 to the end face electrode 8.

  As the material of the end face electrode 8, it is preferable to use a material that is less likely to be oxidized than the material forming the current collector 3. In this case, the morphological stability of the end face electrode 8 against oxidation / reduction is improved, and the electricity collected by the current collector 3 can be reliably taken out. Therefore, the fuel cell single cell 1 excellent in connection reliability is obtained. In addition, since the end face electrode 8 is difficult to oxidize during long-time operation, the reliability of long-term operation can be improved. Moreover, since a conductive material is not required for the support 4, the room for selecting the material of the support 4 is widened. Therefore, the fuel cell single cell 1 having advantages such as an improvement in cell strength by improving the strength of the support 4 and cost reduction by not using a conductive material for the support 4 can be obtained. Other functions and effects are the same as those of the first embodiment.

  The material of the end face electrode 8 that is less likely to be oxidized than the material forming the current collector 3 can be selected with reference to an Ellingham diagram or the like. Specific examples of the material of the end face electrode 8 include W, Mo, Cu, Au, Ag, Pt group, and alloys thereof.

  The end face electrode 8 may be provided so as to be in contact with only the support 4 on the cell end face, or may be provided so as to be in contact with the support 4 and the anode 2. Further, a part of the end face electrode 8 may exist in the pore 41 of the support 4. In this case, the bondability of the end face electrode 8 to the cell end face can be improved. A part of the end face electrode 8 may also exist in the pores 21 and the gap 32 of the anode 2.

(Experimental example)
Hereinafter, it demonstrates more concretely using an experiment example.
<Single fuel cell of sample 1>
-Material preparation-
A slurry was prepared by mixing 8YSZ powder (average particle size: 0.5 μm), carbon (pore forming agent), polyvinyl butyral, isoamyl acetate and 1-butanol with a ball mill. Using the doctor blade method, the slurry was applied in layers on a resin sheet, dried, and then the resin sheet was peeled off to prepare a support forming sheet. The thickness of the support forming sheet was 110 μm. The average particle diameter is the particle diameter (diameter) d50 when the volume-based cumulative frequency distribution measured by the laser diffraction / scattering method shows 50% (hereinafter the same).

  NiO powder (average particle size: 0.6 μm), 8YSZ powder (average particle size: 0.2 μm), carbon (pore forming agent), polyvinyl butyral, isoamyl acetate and 1-butanol are mixed in a ball mill. A slurry was prepared. The mass ratio of NiO powder and 8YSZ powder is 65:35. Using the doctor blade method, the slurry was applied in layers on a resin sheet and dried to prepare an anode forming sheet with a resin sheet. The thickness of the anode forming sheet was 30 μm. Note that the amount of carbon in the anode forming sheet is small compared to the support forming sheet.

  NiO powder (average particle size: 0.6 μm), ethyl cellulose (binder), dihydroterpineol acetate (solvent), dispersant, leveling agent and anti-settling agent are stirred with a planetary mixer and then kneaded with a three-roller. As a result, a paste for forming a current collector was prepared. A current collector paste was pattern-printed on the surface of the anode forming sheet on the resin sheet using a screen printing method. The printing pattern here is a linear pattern composed of 71 linear pastes arranged at equal intervals, and is for forming a plurality of linear current collectors. The line width of each linear paste was 100 μm, the pitch between lines was 1000 μm, and the line thickness was 80 μm. After drying each linear paste, the resin sheet was peeled off to prepare an anode forming sheet with a current collector forming paste on which one of the linear patterns of the current collector forming paste was printed.

  A slurry was prepared by mixing 8YSZ powder (average particle size: 0.2 μm), polyvinyl butyral, isoamyl acetate and 1-butanol with a ball mill. Using the doctor blade method, the slurry was applied in layers on a resin sheet, dried, and then the resin sheet was peeled off to prepare a solid electrolyte layer forming sheet. The thickness of the solid electrolyte layer forming sheet was 5.0 μm.

A slurry was prepared by mixing CeO ₂ (10GDC) powder (average particle size: 0.3 μm) doped with 10 mol% Gd, polyvinyl butyral, isoamyl acetate, 2-butanol and ethanol with a ball mill. . Using the doctor blade method, the slurry was applied in layers on a resin sheet, dried, and then the resin sheet was peeled off to prepare an intermediate layer forming sheet. The thickness of the intermediate layer forming sheet was 4.0 μm.

A cathode forming paste was prepared by kneading LSC (La _0.6 Sr _0.4 CoO ₃ ) powder (average particle size: 2.0 μm), ethyl cellulose, and terpineol with three rolls.

  After stirring Cu powder (average particle size: 0.5 μm), acrylic resin (binder), dihydroterpineol acetate (solvent), dispersant, leveling agent and anti-settling agent with a planetary mixer, The paste for end face electrode formation was prepared by kneading, adding dihydroterpineol acetate (solvent) and stirring with a planetary mixer.

  A support forming sheet, an anode forming sheet with a current collector forming paste, a solid electrolyte layer forming sheet, and an intermediate layer forming sheet were laminated in this order and pressure bonded. In addition, the printing surface of the linear pattern in the anode forming sheet with the current collector forming paste is disposed on the support forming sheet side. In addition, a CIP molding method was used for pressure bonding. At this time, the CIP molding conditions were a temperature of 80 ° C., a pressing force of 50 MPa, and a pressing time of 10 minutes. The obtained pressure-bonded body was punched into a square shape to obtain a laminate. The obtained laminate was degreased. In addition, the current collector paste is exposed on two opposing end surfaces of the four end surfaces of the laminate.

  The laminate was fired at 1350 ° C. for 2 hours in an air atmosphere. As a result, a sintered body was obtained in which the support (200 μm), the anode (20 μm), the solid electrolyte layer (3 μm), and the intermediate layer (3 μm) were laminated in this order. On the surface of the obtained sintered body on the support side of the anode, a plurality of dense current collector forming materials made of NiO protruded corresponding to the linear pattern. The plurality of current collector forming materials were formed in a state of being bitten into the support body by the pressure bonding. In addition, the current collector forming material was exposed on two opposing end surfaces of the four end surfaces of the sintered body. At this time, no gap was formed between the current collector forming material embedded in the support body and the support body.

  A cathode forming paste was applied to the surface of the intermediate layer of the sintered body by a screen printing method and baked (baked) at 950 ° C. for 2 hours in an air atmosphere to form a layered cathode (50 μm). The external shape of the cathode was formed smaller than the external shape of the anode. Thereby, a flat cell was obtained.

  The end face electrode forming paste was applied to one of the cell end faces from which the current collector forming material was exposed in the obtained cell by using a dip coating method. At this time, the solid electrolyte layer, the intermediate layer, and the cathode were masked so that the end face electrode forming paste was not applied. Thereby, the end surface electrode forming paste was applied to the end surface of the support and the end surface of the anode among the cell end surfaces. The end face electrode forming paste was impregnated into the pores of the support from the end face of the support.

  The support and the anode coated with the end face electrode forming paste were exposed to a reducing atmosphere, and the solid electrolyte layer, the intermediate layer and the cathode were not exposed to the reducing atmosphere. Then, the support and the anode coated with the end face electrode forming paste were subjected to reduction treatment in a reducing atmosphere with hydrogen gas at 800 ° C. for 12 hours. As a result, NiO contained in the current collector forming material was reduced to form a current collector made of Ni. Further, NiO contained in the anode was reduced to Ni. Further, Cu contained in the end face electrode forming paste was combined with Ni formed in the anode to form a conductive path and an end face electrode. Thus, a fuel cell single cell of Sample 1 was obtained.

  In the fuel cell single cell of Sample 1, the surface except for the surface connected to the anode in the current collector was covered with voids formed by the volume shrinkage of NiO by about 40%. Moreover, in the fuel cell single cell of Sample 1, one end of the current collector was connected to the end face electrode. Further, in the single fuel cell of Sample 1, the effective area ratio of the current collector with respect to the effective power generation area of the cell was 10%.

  In the production of the fuel cell single cell of sample 1, the conditions for pattern printing of the current collector forming paste on the surface of the anode forming sheet were variously changed, so that the fuel cell single cell of sample 2 and the fuel of sample 3 were changed. A single battery cell, Sample 4 fuel cell single cell, was obtained. The effective area ratio of the current collector to the power generation effective area of the cell was 20% for the sample 2 fuel cell, 25% for the sample 3 fuel cell, and 30% for the sample 4 fuel cell. . When the effective area ratio of the current collector exceeded 30%, the joint surface between the support and the anode tended to decrease. Therefore, it was confirmed that by setting the effective area ratio of the current collecting portion to 30% or less, it becomes easy to obtain the single fuel cell 1 that is advantageous for suppressing the peeling between the support 4 and the anode 2. Moreover, the tendency which the space | gap which covers a current collection part decreased was seen as the effective area ratio of a current collection part became large. Therefore, it was confirmed that the effective area ratio of the current collector is desirably 20% or less from the viewpoint of sufficiently securing a gap covering the current collector.

  In the production of the fuel cell single cells of Samples 1 to 4, the current collector forming paste is pattern printed on the surface of the anode forming sheet. Therefore, as described above, in each fuel cell single cell, the ratio of the conductive material (Ni) present at the interface between the current collector and the anode is larger than the ratio of the conductive material (Ni) present inside the anode. It can be said that it is clear without performing line analysis by EDX measurement.

  The present invention is not limited to the above-described embodiments and experimental examples, and various modifications can be made without departing from the scope of the invention. Moreover, each structure shown by each embodiment can be arbitrarily combined in each embodiment and between each embodiment.

DESCRIPTION OF SYMBOLS 1 Fuel cell single cell 2 Anode 3 Current collecting part 4 Support body 5 Solid electrolyte layer 6 Cathode

Claims (7)

An anode (2);
At least one current collector (3) protruding from one side of the anode;
A porous support (4) disposed on one side of the anode and covering one side of the anode from which the current collector projects;
A solid electrolyte layer (5) disposed on the other side of the anode;
A fuel cell single cell (1) having a cathode (6) disposed on the opposite side to the anode side in the solid electrolyte layer.   2. The fuel cell single cell according to claim 1, wherein a surface (31) excluding a surface (30) connected to the anode in the current collector is covered with a gap (32). The current collector and the anode both include a conductive material,
3. The fuel cell single cell according to claim 1, wherein a ratio of the conductive material present at the interface (23) between the current collector and the anode is larger than a ratio of the conductive material present inside the anode. . 4. The difference between the linear thermal expansion coefficient of the conductive material contained in the current collector and the linear thermal expansion coefficient of the conductive material contained in the anode is 1 × 10 ⁻⁶ / K or less. Single fuel cell.   5. The fuel cell single cell according to claim 1, wherein at least one cell end face has an end face electrode (8) that is electrically connected to the current collector. 6.   The fuel cell single cell according to claim 5, wherein the material of the end face electrode is a material that is less susceptible to oxidation than the material forming the current collector.   The single cell of fuel cell according to any one of claims 1 to 6, wherein an effective area ratio of the current collecting unit with respect to an effective power generation area of the cell is 3% or more and 30% or less.

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