JP2009081113A - Horizontal stripe type fuel battery cell and fuel battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a horizontal stripe type fuel battery cell of a high yield which does not lengthwise crack in a longitudinal direction from a right upper section of a gas passage section, even at the time of manufacturing or power generation of the cell. <P>SOLUTION: In the horizontal stripe type fuel battery cell 10 in which a plurality of power generation elements 13 having an inside electrode 13a, a solid electrolyte 13b and an outside electrode 13c laminated in sequence are arranged in parallel on the surface of an electrically-isolated porous support substrate 11 having three or more of gas passages 12 in a width direction, with the inside electrode 13a of the power generation element 13 and the outside electrode 13c of the other power generation element 13 adjacent to the power generation element 13 are electrically connected with each other, a diameter of the gas passage 12 located at either side in a width direction of the porous support substrate 11 is smaller than a diameter of the other gas passage located nearer a center side than that gas passage 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a horizontal stripe fuel cell and a fuel cell using the same.

  In recent years, various types of fuel cells in which a cell stack formed by connecting a plurality of fuel cells is accommodated in a storage container have been proposed as next-generation energy. As such a fuel cell, various types such as a polymer electrolyte fuel cell, a phosphoric acid fuel cell, a molten carbonate fuel cell, and a solid electrolyte fuel cell are known. In particular, solid electrolyte fuel cells have advantages such as high power generation efficiency and high operating temperatures of 600 ° C to 1000 ° C, so that the exhaust heat can be used, and research and development has been promoted. Yes.

FIG. 7 is a partially broken perspective view showing a conventional solid oxide fuel cell. This solid electrolyte fuel cell 10 is called a horizontal stripe type, and a fuel electrode layer 13a, a solid electrolyte 13b, and an air electrode layer 13c are sequentially laminated on the surface of a flat porous support substrate 11 that is an electrical insulator. A plurality of power generating elements 13 having a multilayer structure are formed at predetermined intervals in the longitudinal direction of the porous support substrate 11. The power generating elements 13 adjacent to each other are electrically connected in series by inter-element connection members 17 (also referred to as “interconnectors”). That is, the fuel electrode layer 13 a of one power generation element 13 and the air electrode layer 13 c of the other power generation element 13 are connected by the inter-element connection member 17. A plurality of gas flow paths 12 penetrating in the longitudinal direction are formed inside the porous support substrate 11.
In the horizontal stripe fuel cell 10, the oxygen ion conductivity of the solid electrolyte 13 b increases at 600 ° C. or higher. Therefore, a gas containing oxygen flows through the air electrode layer 13 c at such a temperature, and the fuel electrode layer 13 a By flowing a gas containing hydrogen through the gas flow path 12, the oxygen concentration difference between the air electrode layer 13c and the fuel electrode layer 13a increases, and a potential difference occurs between the air electrode layer 13c and the fuel electrode layer 13a. To do.
Due to this potential difference, oxygen ions move from the air electrode layer 13c to the fuel electrode layer 13a via the solid electrolyte 13b. The moved oxygen ions are combined with hydrogen in the fuel electrode layer 13a to become water, and at the same time, electrons are generated in the fuel electrode layer 13a.
That is, the electrode reaction of the following formula (1) occurs in the air electrode layer 13c, and the electrode reaction of the following formula (2) occurs in the fuel electrode layer 13a.
Air electrode layer 3c: 1 / 2O ₂ + 2e ⁻ → O ²⁻ (1)
The fuel electrode layer _{^{3a: O 2- + H 2 →}} H 2 O + 2e - ·· (2)
Then, by electrically connecting the fuel electrode layer 13 a of one power generation element 13 and the air electrode layer 13 c of the other power generation element 13, the fuel electrode layer 13 a of one power generation element 13 is connected to the other power generation element 13. Electrons move to the air electrode layer 13c, and an electromotive force is generated between the two electrodes.
Thus, in the solid oxide fuel cell, by supplying oxygen and hydrogen, the above reaction is continuously caused to generate an electromotive force to generate electric power (see, for example, Patent Documents 1 and 2).
JP 10-003932 A JP 2006-269276 A

However, in the conventional fuel cell, since the Ni component of the porous support substrate 11 and the fuel electrode layer 13a is NiO by firing in an oxygen-containing atmosphere at the time of production, for example, when this is reduced by reduction treatment Or, when being reduced by being exposed to a reducing atmosphere during power generation, there is a risk of longitudinal cracking in the longitudinal direction (gas flow direction) in the upper portion of the gas flow path due to the generated stress strain. This vertical crack occurs not only when the strength of the fuel cell is locally reduced but also when the strength difference in the same cell is large. And this vertical crack location is very high in the gas flow path in the both ends of the arrangement direction. Therefore, there exists a malfunction that the yield of the product of a fuel cell is low.
In particular, in recent years, from the viewpoint of increasing the amount of power generation in a fuel cell and making it more compact, the fuel cell tends to be thinner and wider, so the vertical crack is likely to occur.
An object of the present invention is to provide a high-yield horizontal-striped fuel cell that does not cause vertical cracks in the longitudinal direction from directly above the gas flow path even when the horizontal-striped fuel cell is manufactured and during power generation. .

  As a result of intensive studies to solve the above problems, the present inventors have found that the strength at the end in the width direction of the porous support substrate is the lowest among the porous support substrates, and the center in the width direction of the porous support substrate. It has been found that the strength increases as it goes to the portion, and that the strength decrease increases as the hole diameter (area) of the gas flow path increases. From this, it was found that by making the hole diameter of the gas flow path closest to the side surface of the porous support substrate smaller than the hole diameter of the other gas flow paths, vertical cracks can be suppressed during the production of fuel cells and during power generation. Thus, the present invention has been completed.

That is, the horizontal stripe fuel cell and the fuel cell according to the present invention have the following configurations.
(1) A plurality of power generation elements in which an inner electrode, a solid electrolyte, and an outer electrode are sequentially laminated are arranged in parallel on the surface of an electrically insulating porous support substrate having three or more gas flow paths in the width direction. The inner electrode of the power generation element and the outer electrode of another power generation element adjacent to the power generation element (of the power generation elements adjacent to each other, the inner electrode of one power generation element and the outer electrode of the other power generation element And other gas in which the diameter of the gas flow path at both ends in the width direction of the porous support substrate is located closer to the center than the gas flow path. A horizontally-striped fuel cell characterized by being smaller than the diameter of the flow path.
(2) The diameter of another gas flow channel located on the center side in the width direction of the porous support substrate is 37% or more and 65% or less with respect to the thickness of the porous support substrate (1) ) Horizontal stripe fuel cell.
(3) The diameter of the gas flow path at both ends in the width direction of the porous support substrate is 34% or more and 50% or less with respect to the thickness of the porous support substrate (1) or (2) ) Horizontal stripe fuel cell.
(4) The horizontal stripe fuel cell according to any one of (1) to (3), wherein the porous support substrate has a thickness of 2.0 mm to 3.5 mm.
(5) The horizontal stripes according to any one of (1) to (4), wherein the power generation element is disposed closer to a center side than gas flow paths at both ends in the width direction of the porous support substrate. Type fuel cell.
(6) A fuel cell comprising a plurality of horizontally-striped fuel cells according to any one of (1) to (5) contained in a storage container.

According to the laterally striped fuel cell of the present invention, the diameter of the gas flow path at both ends in the width direction of the porous support substrate is made smaller than the diameter of the gas flow path on the center side. The strength at both ends in the direction is increased, and therefore vertical cracks can be suppressed during production and power generation of the horizontal stripe fuel cell, and a horizontal stripe fuel cell having a high yield can be provided.
Moreover, according to the fuel cell of the present invention, since the above-described horizontal stripe fuel cell is used, a high power generation amount can be obtained while ensuring reliability.

Hereinafter, an embodiment of a horizontal stripe fuel cell according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a partially broken perspective view showing the structure of a horizontal stripe fuel cell according to the present invention. In this fuel cell 10, a plurality of power generation elements 13 are arranged along the longitudinal direction of the porous support substrate 11 on the front and back surfaces of a hollow flat plate-like electrically insulating porous support substrate 11. This is called a “horizontal stripe type” connected in series via the inter-connection member 17.

  As shown in FIG. 1, the horizontally-striped fuel cell of the present invention is configured by arranging a plurality of power generating elements 13 on the front and back surfaces of a porous support substrate 11 at predetermined intervals in the longitudinal direction. ing. Each power generating element 13 has a layer structure in which a current collecting fuel electrode layer 23, an active fuel electrode layer 13a, a solid electrolyte 13b, and an air electrode layer 13c are sequentially stacked.

  The power generating elements 13 adjacent to each other on the front and back surfaces of the porous support substrate 11 are connected in series by an inter-element connection member 17 including a first current collecting layer 17a and a second current collecting layer 17b (see FIG. 2). . That is, a first current collecting layer 17a is formed on the active fuel electrode layer 13a of one power generating element 13, and the first current collecting layer 17a is gas-sealed by the solid electrolyte 13b including its both ends in the longitudinal direction. It coat | covers in the state and is exposed to the strip | belt shape from the solid electrolyte 13b. The exposed portion of the first current collecting layer 17a is covered with the second current collecting layer 17b, and this second current collecting layer 17b is formed on the air electrode layer 13c of the other power generating element 13, thereby generating power. The elements 13 are electrically connected in series.

  The porous support substrate 11 is porous, and a plurality of fuel gas passages 12 having a small inner diameter are provided through the porous support substrate 11 so as to extend in the longitudinal direction and separated by the partition walls 51. The number of the gas flow paths 12 is preferably 3 to 20, for example, and more preferably 6 to 17, in terms of power generation performance and structural strength. In this way, by forming a plurality of gas flow paths 12 inside the porous support substrate 11, the porous support substrate 11 can be compared with the case where one large gas flow path is formed inside the porous support substrate 11. Can be made into a flat plate shape, and the area of the power generation element 13 per volume of the fuel cell 1 can be increased to increase the amount of power generation. Therefore, the number of fuel cells for obtaining the required power generation amount can be reduced. In addition, the number of connection points between the fuel cells can be reduced.

  By flowing a fuel gas (hydrogen gas) through the gas flow path 12 and exposing the air electrode layer 13c to an oxygen-containing gas such as air, the above-described equation (1) is obtained between the active fuel electrode layer 13a and the air electrode layer 13c. ), Electrode reaction shown in (2) occurs, a potential difference is generated between the two electrodes, and power is generated.

  As shown in FIG. 1, the porous support substrate 11 according to the present invention has another gas flow in which the diameter of the gas flow path 12 at both ends in the width direction X is closer to the center side (inner side in the width direction). The configuration is smaller than the diameter of the path 12. By adopting such a configuration, it is possible to improve the conventional problem that the strength at the end in the width direction of the porous support substrate 11 is weak, and that vertical cracks occur due to the difference in strength depending on the portion in the width direction. . That is, the structure of the present invention can reduce the difference in strength in the width direction portion of the porous support substrate 11 and ensure a uniform strength distribution as a whole. As a result, when the fuel cell 10 is manufactured, the porous support substrate 11 is caused by the stress strain generated when the fuel cell 10 is reduced by the reduction treatment after firing in the oxygen-containing atmosphere, or when it is reduced by being exposed to the reducing atmosphere during power generation. Thus, the fuel cell 10 with a high yield can be manufactured.

The diameter of the other gas channel 12 on the center side in the width direction of the porous support substrate 11 is preferably 37% or more and 65% or less with respect to the thickness of the porous support substrate 11. On the other hand, the diameter of the gas flow path 12 at both ends in the width direction of the porous support substrate 11 is preferably 34% or more and 50% or less with respect to the thickness of the porous support substrate 11. The diameter of the gas flow path 12 is set from the viewpoint that the lower limit value increases the amount of gas diffusion to the fuel electrode, and the upper limit is that the strength at the center and the end in the width direction of the porous support substrate 11 is improved. It is set from the viewpoint.
The porous support substrate 11 includes a flat plate portion 11a that exists on the center side in the width direction, and a halved columnar portion 11b that exists at both ends in the width direction and whose outer surface is a curved surface. The gas flow paths 12 at both ends in the width direction of the support substrate 11 exist across the half cylinder part 11b or the half cylinder part 11b and the flat part 11a. Due to the half columnar portion 11b, stress concentration at both ends in the width direction of the porous support substrate 11 can be suppressed. And since the gas flow path 12 at both ends in the width direction of the porous support substrate 11 exists across the half cylinder part 11b or the half cylinder part 11b and the flat part 11a, the porous support A power generation element can be efficiently formed on the substrate 11, and a compact and high-power generation cell can be obtained.
By setting the diameter and the position of both ends of the gas flow path 12 at the center side and both ends in the width direction of the porous support substrate 11 within the above range, the difference in strength in the width direction portion of the porous support substrate 11 is obtained. It is possible to further reduce and secure a uniform intensity distribution as a whole.
In addition, although the cross-sectional shape of the gas flow path may not be strictly circular, in the present invention, the maximum width in the thickness direction of the support substrate is defined as the diameter even when it is not circular.

  The gas flow paths 12 at both ends in the width direction of the porous support substrate 11 may not contribute as a gas supply source to the power generation element 13 in some cases. Since the gas flow path 12 at both ends has a smaller flow path diameter than the other gas flow paths 12, the resistance at the gas introduction port of the porous support substrate 11 is increased, and the pressure loss in the gas flow paths 12 at both ends is large. Therefore, the supply of gas in this flow path is insufficient, which hinders good power generation. Therefore, it is preferable that the power generating element 13 is disposed closer to the center than the gas flow paths 12 at both ends in the width direction of the porous support substrate 11.

  A plurality of the fuel cells 10 are assembled to assemble a cell stack as shown in FIG. A conductive member (not shown) for taking out the electric power generated in the cell stack to the outside of the fuel cell is attached to both ends of the cell stack, and the fuel cell can be manufactured by accommodating it in a storage container. An oxygen-containing gas such as air is introduced into the storage container, and a fuel gas such as hydrogen is introduced into the fuel gas manifold 50 through an introduction pipe. If the fuel gas is introduced into the fuel cell 10 through the fuel gas manifold 50 and the fuel cell 10 is heated to a predetermined temperature, the fuel cell 10 can generate electric power. The used fuel gas and oxygen-containing gas are exhausted from the front end E of the fuel battery cell 10 and discharged out of the storage container.

As shown in FIG. 2, the fuel cells 10 are electrically connected to each other via inter-cell connection members 19.
That is, at the lower end of the cell stack, the inter-element connection member 17 b is provided at the lower end of one fuel cell 10 and is electrically connected to the air electrode layer 13 c of the one fuel cell 10. The inter-element connection member 17 b is electrically connected to the fuel electrode layer 13 a via the inter-cell connection member 19 and the inter-element connection members 17 b and 17 a of the other fuel cell 10. On the other hand, at the upper end of each fuel cell 10, the air electrode layer 13 c on one surface of the porous support substrate 11 and the fuel electrode layer 13 a on the other surface (back surface) are connected via an inter-element connection member 17. Has been. Thereby, the electric current which generate | occur | produced in each power generation element part 13 of one surface of one porous support substrate 11 can be sent to each power generation element part 13 of the other surface (back surface). That is, the power generating element portion 13 between the front and back surfaces of one porous support substrate 11 can be electrically connected in series.
In this way, the cell stack can densely arrange the fuel cells 10 as long as the fuel cells 10 described above are electrically connected to each other via the inter-cell connection member 19. The volume of the hit cell stack can be reduced. Therefore, a small and highly efficient cell stack can be provided.

Hereinafter, the material of each member constituting the fuel battery cell 10 will be described in detail.
(Porous support substrate)
The porous support substrate 11 according to the present invention is made of Mg oxide (MgO), Ni or Ni oxide (NiO), and a rare earth element oxide. Examples of rare earth elements constituting rare earth element oxides include Y, La, Yb, Tm, Er, Ho, Dy, Gd, Sm, and Pr. Preferably, Y ₂ O ₃ or Yb ₂ O ₃ , especially Y ₂ O ₃ .

MgO is 70 to 80% by volume, rare earth element oxide is 10 to 20% by volume, Ni or NiO (NiO is usually reduced by hydrogen gas and present as Ni during power generation) is 10 to 25 in terms of NiO. It is good to contain in the porous support substrate 11 in the range of volume%, especially 15-20 volume%.
The thermal expansion coefficient of the porous support substrate 11 is usually about 10.5 to 12.5 × 10 ⁻⁶ (1 / K).

The porous support substrate 11 needs to be electrically insulative in order to prevent an electrical short circuit between the power generating elements 13, and normally has a resistivity of 10 Ω · cm or more. When the content of Ni or the like exceeds the above range, the electric resistance value tends to decrease. Further, when the content of Ni or the like is less than the above range, it is not different from the case where a rare earth element oxide (for example, Y ₂ O ₃ ) is used alone, and it is difficult to adjust the thermal expansion coefficient with the power generation element 13. Tend to be.

  The porous support substrate 11 must be able to introduce the fuel gas in the fuel gas flow path 12 up to the surface of the active fuel electrode layer 13a, and therefore needs to be porous. In general, the open porosity should be 25% or more, especially in the range of 30-40%.

(Fuel electrode layer)
The fuel electrode layer causes the electrode reaction of the above formula (2), and in this embodiment, the active fuel electrode layer 13a on the solid electrolyte 13b side and the current collecting fuel electrode layer on the porous support substrate 11 side. 23 and a two-layer structure.
The active fuel electrode layer 13a on the solid electrolyte 13b side is formed of a known porous conductive ceramic. For example, it is composed of ZrO ₂ (stabilized zirconia) in which a rare earth element is dissolved, and Ni and / or NiO (hereinafter referred to as Ni or the like). As the stabilized zirconia in which the rare earth element is dissolved, the same one used for the solid electrolyte 13b described later is preferably used.

The stabilized zirconia content in the active fuel electrode layer 13a is preferably in the range of 35 to 65% by volume, and the content of Ni or the like is 65 to 35% in terms of NiO in order to exhibit good current collecting performance. % Should be in the range.
Further, the open porosity of the active fuel electrode layer 13a is preferably 15% or more, particularly preferably in the range of 20 to 40%.

The thermal expansion coefficient of the active fuel electrode layer 13a is usually about 12.3 × 10 ⁻⁶ (1 / K).
The active fuel electrode layer 13a has a thickness of 5 to 5 because it absorbs thermal stress generated due to the difference in thermal expansion from the solid electrolyte 13b and prevents cracking or peeling of the active fuel electrode layer 13a. It is desirable to be in the range of 15 μm.
Among the fuel electrode layers, the current collecting fuel electrode layer 23 on the porous support substrate 11 side is a mixture of Ni or Ni oxide and rare earth element oxide, like the porous support substrate 11.

The Ni or Ni oxide (NiO is usually reduced by hydrogen gas and present as Ni during power generation) is contained in the rare earth element oxide in a range of 30 to 60% by volume in terms of NiO. Is good. By adjusting within this range, the difference in thermal expansion between the porous support substrate 11 and the current collecting fuel electrode layer 23 can be made 2 × 10 ⁻⁶ (1 / K) or less. The current collecting fuel electrode layer 23 needs to be conductive so as not to impair the flow of current, and it is generally desirable that the current collecting fuel electrode layer 23 have a conductivity of 400 S / cm or more. From the viewpoint of having good electrical conductivity, the content of Ni or the like is desirably 30% by volume or more.

The thermal expansion coefficient of the current collecting fuel electrode layer 23 is usually about 11.5 × 10 ⁻⁶ (1 / K).
In addition, the thickness of the current collecting fuel electrode layer 23 is desirably 80 μm or more from the viewpoint of improving electric conductivity.
As described above, if the fuel electrode is formed in two layers with the active fuel electrode layer 13a on the solid electrolyte 13b side and the current collecting fuel electrode layer 23 on the porous support substrate 11 side, the porous support substrate 11 side is provided. By adjusting the Ni amount or NiO amount in terms of NiO of the current collecting fuel electrode layer 23 within the range of 30 to 60% by volume, the thermal expansion coefficient is reduced without impairing the bonding property with the power generation element 13. The thermal expansion coefficient of the solid electrolyte 13b, which will be described later, can be approached. For example, the difference in thermal expansion between the two can be less than 2 × 10 ⁻⁶ / (1 / K). Therefore, since the thermal stress generated due to the difference in thermal expansion between the fuel cell 10 during production, heating, and cooling can be reduced, cracking and peeling of the fuel electrode can be suppressed. . For this reason, even when fuel gas (hydrogen gas) is flowed to generate power, the consistency of the thermal expansion coefficient with the porous support substrate 11 is maintained stably, and cracks due to thermal expansion differences can be effectively avoided. it can.

(Solid electrolyte)
The solid electrolyte 13b is composed of a dense ceramic made of stabilized ZrO ₂ composed of ZrO ₂ which was a solid solution of rare earth or an oxide thereof.
Here, as rare earth elements to be dissolved or oxides thereof, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, etc. Or these oxides etc. are mentioned, Preferably, Y, Yb, or these oxides are mentioned. The solid electrolyte 13b is a lanthanum gallate system (LaGaO ₃ ) having a thermal expansion coefficient substantially equal to that of stabilized ZrO ₂ (8 mol% Yttoria Stabilized Zirconia, hereinafter referred to as “8YSZ”) in which 8 mol% of Y is dissolved. System) solid electrolytes. The solid electrolyte 13b has a thickness of 10 to 100 μm, for example, and has a relative density (according to Archimedes method) of 93% or more, preferably 95% or more.
Such a solid electrolyte 13b has a function as an electrolyte for bridging electrons between electrodes, and at the same time has a gas barrier property to prevent leakage of fuel gas or oxygen-containing gas (gas permeation). .

(Air electrode layer)
The air electrode layer 13c is made of conductive ceramics. Examples of conductive ceramics include ABO ₃ type perovskite oxides. Examples of such perovskite oxides include transition metal type perovskite oxides, preferably LaMnO ₃ oxides, LaFeO ₃ oxides. Examples thereof include transition metal type perovskite oxides having La at the A site, such as oxides based on oxides and LaCoO ₃ oxides. More preferably, from the viewpoint of high electrical conductivity at a relatively low temperature of about 600 to 1000 ° C., a LaCoO ₃ oxide is used.
In the perovskite oxide described above, La and Sr may coexist at the A site, and Fe, Co, and Mn may coexist at the B site.
Such an air electrode layer 13c can cause the electrode reaction of the above-described formula (1).
Further, the air electrode layer 13c has an open porosity of, for example, 20% or more, and preferably 30 to 50%. If the open porosity is within the above-described range, the air electrode layer 13c can have good gas permeability.
Moreover, the thickness of the air electrode layer 13c is set in a range of 30 to 100 μm, for example. If it exists in an above-described range, the air electrode layer 13c can have favorable current collection property.

(Element connection member)
The inter-element connection member 17 used for connecting adjacent power generating element portions 13 in series electrically connects the fuel electrode layer 13a of one power generating element 13 and the air electrode layer 13c of the other power generating element 13 adjacent to each other. The first current collecting layer 17a and the second current collecting layer 17b are electrically connected to each other.
The first current collecting layer 17a is formed from conductive ceramics, but it needs to have reduction resistance and oxidation resistance because it comes into contact with an oxygen-containing gas such as fuel gas (hydrogen gas) and air. is there. For this reason, lanthanum chromite perovskite oxides (LaCrO ₃ oxides) are generally used as the conductive ceramics. In order to prevent leakage of fuel gas passing through the gas flow path 12 in the insulating support substrate 11 and oxygen-containing gas such as air passing outside the air electrode layer 13c, the conductive ceramics must be dense. For example, it is preferable to have a relative density (Archimedes method) of 93% or more, particularly 95% or more. In addition, a sealing property can also be improved by interposing an appropriate bonding layer (for example, Y ₂ O ₃ ) between the end face of the first current collecting layer 17a and the end face of the solid electrolyte 13b.
Moreover, as the 1st current collection layer 17a, it is good also as a two-layer structure of a metal layer and the metal glass layer containing glass. The metal layer is made of, for example, an alloy of Ag and Ni, and the metal glass layer is made of Ag and glass. Due to the metal glass layer, leakage of fuel gas through the gas flow path 12 in the porous support substrate 11 to the second current collecting layer and leakage of oxygen-containing gas through the outside of the air electrode layer 13c to the metal layer Can be effectively prevented.
On the other hand, the second current collecting layer 17b is porous. The second current collecting layer 17b can be made of a porous material composed of a conductive ceramic (for example, an air electrode material) such as LaCoO _{3 and} a noble metal such as Ag—Pd. When the amount of the second current collecting material applied to the air electrode layer 13c is small, the second current collecting material penetrates into the pores of the air electrode layer 13c and is not formed as a layer. In particular, since a precious metal such as Ag-Pd has a small coating amount for cost reduction, the air electrode layer 13c is configured by mixing an air electrode layer material and a current collecting material such as Ag-Pd, and the second current collecting layer. Is not formed. On the other hand, a conductive ceramic such as LaCoO ₃ is applied in a large amount. In this case, the second current collecting layer is formed on the air electrode layer 13c.

(Production method)
Next, a method for manufacturing the horizontal stripe fuel cell described above will be described with reference to FIGS.
First, the support substrate molded body 41 is produced. As a material of the support substrate molded body 41, an MgO powder having an average particle diameter (D ₅₀ ) (hereinafter simply referred to as “average particle diameter”) on a volume basis is 0.1 to 10.0 μm, and if necessary, a thermal expansion coefficient. Ni powder, NiO powder, Y ₂ O ₃ powder, rare earth element stabilized zirconia powder (YSZ), etc. are blended at a predetermined ratio and mixed for adjustment or improvement of bonding strength, and the thermal expansion coefficient after mixing Is adjusted to substantially match that of the solid electrolyte 13b. This mixed powder is mixed with a solvent composed of a pore agent, a cellulosic organic binder, and water, extruded, and formed into a hollow plate shape having a gas flow path 42 inside as shown in FIG. Then, a flat support substrate molded body 41 is prepared, dried, and calcined at 900 ° C. to 1100 ° C. The diameter of the gas channel is adjusted during extrusion.

Next, a fuel electrode layer and a solid electrolyte are produced. First, for example, NiO powder, Ni powder, and YSZ powder are mixed, a pore agent is added thereto, an acrylic binder and toluene are mixed to form a slurry, and the slurry is applied by a doctor blade method and dried. Then, an active fuel electrode layer tape 43a having a thickness of 5 to 20 μm is produced (FIG. 4A).
Next, in the same manner as the active fuel electrode layer tape 43a, for example, NiO powder, Ni powder, and rare earth element oxide such as Y ₂ O ₃ are mixed, a pore agent is added thereto, an acrylic binder, Toluene is mixed to form a slurry, and the slurry is applied by a doctor blade method and dried to prepare a current collecting fuel electrode layer tape 43 having a thickness of 80 μm or more. The active fuel electrode layer tape 43a is attached to the current collecting fuel electrode layer tape 43 (FIG. 4B). The bonded tape is cut in accordance with the shape of the power generating element 13, and a portion for forming an insulating portion is punched out (FIG. 4C).

Thereafter, as shown in FIG. 4D, the current collecting fuel electrode layer tape 43 with the active fuel electrode layer tape 43a attached thereto is attached to the calcined support substrate molded body 41 in a horizontal stripe shape. This is repeated and a plurality of current collecting fuel electrode layer tapes 43 are attached to the surface of the support substrate molded body 41. At this time, one current collecting fuel electrode layer tape 43 and the other current collecting fuel electrode layer tape 43 are arranged with an interval of 3 to 20 mm in width.
Next, it is dried with the current collecting fuel electrode layer tape 43 applied, and then calcined in the temperature range of 900 to 1100 ° C. (FIG. 4D). Then, a masking tape 48 is attached to a portion of the active fuel electrode layer 43a where the first current collecting layer 47a is to be formed (FIG. 4E).

Next, this laminate is immersed in a solid electrolyte solution that is a slurry obtained by adding an acrylic binder and toluene to 8YSZ, and is taken out from the solid electrolyte solution. By this dipping, a layer of the solid electrolyte 43b is applied to the entire surface, and the space cut out in FIG. 4C is filled with the solid electrolyte 43b which is an insulator.
In this state, calcination is performed at 1150 to 1200 ° C. for 2 to 4 hours. During the calcination, the masking tape 48 and the layer of the solid electrolyte 43b applied thereon can be removed. (FIG. 4 (f)).
This is followed by firing at 1450-1550 ° C. for 2-8 hours.

Next, the slurry was mixed with lanthanum cobaltite (LaCoO ₃₎ and isopropyl alcohol by printing, to form the air electrode layer 43c having a thickness of 10 to 100 [mu] m. Then, baking is performed at 950 to 1150 ° C. for 2 to 5 hours (FIG. 4G).
And the sheet | seat of the metal layer which consists of Ag / Ni is affixed on the part which wants to form the 1st current collection layer 47a, Furthermore, the sheet | seat of the metal glass layer containing Ag and glass is affixed (FIG.4 (g)), and then , Heat treatment is performed at 1000 to 1200 ° C.
Finally, the second current collecting layer 47b can be applied to a predetermined position to obtain the horizontal stripe fuel cell 10 (FIG. 4 (i)).

  In addition, about the lamination | stacking method of each above-mentioned layer, you may use any lamination method of tape lamination | stacking, paste printing, dip, and spray spraying. Preferably, the drying process at the time of lamination is short, and each layer is laminated by dipping from the viewpoint of shortening the process.

(Other embodiments)
In the above-described embodiment, the diameter of the gas flow path 12 at both ends in the width direction of the porous support substrate 11 is configured to be smaller than the diameter of the gas flow path 12 located on the center side of the gas flow path 12. However, as shown in FIG. 5, the diameter may be increased from the end toward the center. Thereby, the partial intensity | strength difference in a cell can be made small. Further, by adopting the configuration of the present embodiment, the same effects as those of the above-described one embodiment can be obtained. FIG. 5 shows an example in which only the gas flow path 12 adjacent to the gas flow paths 12 at both ends is made smaller than the diameter on the center side, but is not limited thereto. At this time, it is preferable to increase the diameter L of the gas flow path 12 on the center side excluding the gas flow paths 12 at both ends within a range of 37% to 65% with respect to the thickness T of the porous support substrate 11. Needless to say.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above example, the gas channel 12 has a circular cross section, but it may be substantially circular or elliptical. The material of the porous support substrate 11 is not limited as long as it is porous and is an insulator. Furthermore, although the case where the active fuel electrode layer 13a and the current collecting fuel electrode layer 23 are provided has been described in the above embodiment, the same effect can be obtained even when only the active fuel electrode layer 13a is provided. In addition, various modifications can be made within the scope of the present invention.

  Hereinafter, the horizontal stripe fuel cell of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

A fuel battery cell 10 as shown in FIG. 1 was produced by the above-described manufacturing method, and its strength was examined.
As shown in FIGS. 6 (a) and 6 (b), the fuel cell 10 has 17 gas flow paths 12 on a porous support substrate 11 having a width of 40 mm, a thickness (T) of 2.8 mm, and a length of 200 mm. Provided. The diameter L of the gas flow path 12 was 1.1 mm at both ends, and 1.3 mm except for both ends. Further, the closest distance M between the gas flow path 12 and the surface of the porous support substrate 11 was 0.85 mm at both ends, and 0.75 mm at other than both ends.
The porous support substrate 11 has a flat plate portion 11a having a width direction length of 37.2 mm and a half cylinder portion 11b having a width direction length of 1.4 mm. It exists across the half cylinder part 11b, and the interval between the center positions of the 17 gas flow paths 12 is set to a constant interval of 2.325 mm.
In order to investigate the intensity distribution in the width direction of the fuel cell 10 (the arrangement direction of the gas flow paths 12), as shown in FIG. 6 (a), each region is divided into five regions from the end to the center in the width direction. The intensity in the area was examined. In addition, the intensity | strength was 50 Mpa or more was made into the appropriate reference value as the fuel cell 10. That is, if it is less than 50 MPa, the probability of occurrence of vertical cracks is greatly increased.
The strength was measured by the following method. That is, the cell was cut in the cell length direction at the broken line portion shown in FIG. 6A, a test piece having a length of 30 mm was produced, and measured by a three-point bending strength test (Shimadzu Corporation Autograph) based on JIS1601. . The measurement results are shown in Table 1.
A fuel cell was prepared and evaluated in the same manner as in the above Example, except that this fuel cell 10 was Example 1, and L and M were values shown in Table 1. Table 1 shows the results.
In addition, about Example 5 of Table 1, the thickness of the support substrate was 2 mm, and about Example 6, the thickness of the support substrate was 3.5 mm.

As shown in Table 1, in the fuel cell 10 within the scope of the present invention, the strength distribution in the width direction of the porous support substrate 11 was relatively flat, and the strength difference was 10.3 MPa or less. Moreover, 58 MPa or more was ensured in all regions (Examples 1 to 6).
On the other hand, in Comparative Examples 1 to 3 in which all the diameters of the gas flow path 12 are the same, when the diameter of the gas flow path 12 is 1.0 mm and 1.2 mm (Comparative Examples 1 and 2), the strength is Although the strength distribution increases, the strength distribution varies, and the difference in strength is 14.7 MPa and 16 MPa, respectively, and there is a portion where the strength difference is large in the cell, and it can be seen that cracking occurs at the boundary portion. When the diameter of the gas channel 12 was 1.4 mm (Comparative Example 3), the strength distribution was relatively flat, but the strength at the end was less than 50 MPa. In Comparative Examples 1 and 2, the diameter of the gas flow path 12 is 36% and 42% with respect to the thickness T of the fuel cell 10, respectively.

It is a partially broken perspective view showing one embodiment of a horizontal stripe type fuel cell of the present invention. It is a longitudinal cross-sectional view which shows the cell stack of the horizontal stripe type fuel cell of FIG. It is sectional drawing of the support substrate molded object used for the horizontal stripe type fuel battery cell of this invention. It is a manufacturing-process figure of the fuel battery cell of this invention. It is explanatory drawing which shows the end surface of other embodiment of the horizontal stripe type fuel cell of this invention. (A) is explanatory drawing which shows the end surface of the fuel battery cell of FIG. 1, (b) is explanatory drawing which shows a part of end surface of (a). It is a partially broken perspective view which shows the structure of the conventional fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel cell 11 Porous support substrate 12 Gas flow path 13 Electric power generation element (13a: Active fuel electrode layer, 13b: Solid electrolyte, 13c: Air electrode layer)
17 Inter-element connection member (17a: first current collecting layer, 17b: second current collecting layer)
23 Current collector fuel electrode layer

Claims (6)

  A plurality of power generation elements in which an inner electrode, a solid electrolyte, and an outer electrode are sequentially stacked are arranged in parallel on the surface of an electrically insulating porous support substrate having three or more gas flow paths in the width direction. A horizontally-striped fuel cell in which an inner electrode of an element and an outer electrode of another power generation element adjacent to the power generation element are electrically connected, and gas at both ends in the width direction of the porous support substrate A horizontal-striped fuel cell, wherein the diameter of the flow path is smaller than the diameter of another gas flow path located closer to the center than the gas flow path.   2. The diameter of another gas channel located on the center side in the width direction of the porous support substrate is 37% or more and 65% or less with respect to the thickness of the porous support substrate. Horizontal stripe fuel cell.   The horizontal stripe type according to claim 1 or 2, wherein the diameter of the gas flow path at both ends in the width direction of the porous support substrate is 34% or more and 50% or less with respect to the thickness of the porous support substrate. Fuel cell.   The horizontal stripe fuel cell according to any one of claims 1 to 3, wherein the porous support substrate has a thickness of 2.0 mm to 3.5 mm.   The horizontal stripe fuel cell according to any one of claims 1 to 4, wherein the power generation element is disposed closer to the center than a gas flow path at both ends in the width direction of the porous support substrate.   A fuel cell comprising a plurality of horizontally-striped fuel cells according to claim 1 in a storage container.

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