JP3358640B2 - Manufacturing method of electrode substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a hollow flat electrode substrate having a gas flow passage inside an electrode material used in a solid oxide fuel cell.

[0002]

2. Description of the Related Art Solid oxide fuel cells (hereinafter referred to as SOFCs)
) Has an oxidant electrode and a fuel electrode disposed on both sides of an ion-conductive solid electrolyte, and generates electricity by supplying an oxidant gas and a fuel gas to both electrodes, respectively, as shown below. Ceramics are used as main materials.

Electrolyte: Yttria-stabilized zirconia (YSZ) Oxidizer electrode: Lanthanum manganite (LSM) Fuel electrode: Nickel zirconia cermet (Ni-
YSZ) Since the terminal voltage of the SOFC single cell composed of such a material is at most about 1 V, a practical output is obtained by stacking many single cells in actual power generation. FIG. 2 shows a configuration example in which SOFC single cells are stacked. In FIG. 2, 1 is an electrolyte, 2 is a fuel electrode, 3 is an oxidant electrode, 4 is an interconnector, 5 is a fuel gas flow path, and 6 is an oxidant gas flow path.

A large number of such cells are stacked, and power is generated by supplying fuel to the fuel electrode 2 and oxidant to the oxidant electrode 3 through gas passages 5 and 6 formed in the interconnector 4. . At this time, if the fuel and the oxidant are mixed, the reaction proceeds directly there and the power generation efficiency decreases, so it is necessary to prevent gas leakage. However, in a stack having a structure in which flat ceramics are stacked as shown in FIG. Very difficult to seal with gas.

[0005] In this case, the cell portion composed of the electrolyte 1, the fuel electrode 2, and the oxidizer electrode 3 is manufactured by slurry-coating the electrodes on the electrolyte membrane. When the cell section and the interconnector 4 are stacked, an external stress is applied from above and below in FIG. 2 for conduction between cells and gas filling. For this reason, the electrolyte membrane needs to have a certain thickness in order to give strength to the cell. But,
Since the solid oxide electrolyte 1 used in the SOFC has the lowest conductivity among the cell constituent materials, it is necessary to reduce the thickness as much as possible in order to improve the power generation characteristics.

Therefore, in order to solve the problems of gas tightness and thinning of the electrolyte at the time of lamination, a hollow substrate having a gas flow path 601 inside is made of an electrode material as shown in FIG. A method of forming a cell portion thereon has been considered (JP-A-5-36417). In FIG. 3, 10
1 is an electrolyte, 201 is a fuel electrode, 301 is an oxidizer electrode, 40
Reference numeral 1 denotes an interconnector, 601 denotes an oxidant gas flow path, and 7 denotes a dense film.

In this method, either one of the fuel and the oxidant flows through the gas flow path in the hollow substrate, so that airtightness can be maintained only by performing gas sealing at both ends of the substrate.
In addition, since the cell portion is formed on the substrate, the electrolyte itself is not required to be as strong as the system of FIG. 2 and the electrolyte itself can be made thinner, and improvement in power generation characteristics is expected. As a method for manufacturing such a cell, an oxidizer electrode 301 of a hollow substrate is prepared in advance by extrusion molding, and an electrolyte 10
1. Fuel electrode 201 and interconnector 401 are sprayed,
A method of forming by an EVD method or the like, and a co-sintering method of laminating, forming, and sintering ceramic sheets of each part of a cell manufactured by a doctor blade method or the like are considered.

The extrusion molding method is suitable for molding a material having a fixed cross section, but cannot change the thickness of the substrate or the partial physical properties of the electrode material, and has a small degree of freedom in shape. In addition, since the formation of the substrate and the cell portion is a separate step, the apparatus becomes large-scale, and since the high-temperature processing steps are performed in multiple steps, the sintering of the electrode substrate, which should be porous, progresses during the process, and the density increases. There is a disadvantage that it will. On the other hand, in the co-sintering method, cells are formed by laminating and crimping sheets of different kinds of materials, and the cells are formed by firing. Since the high-temperature treatment process only needs to be performed once, deterioration of the electrodes is minimized. Since the apparatus is simple, it can be said that the method is economically excellent. Further, in the production of a substrate by sheet lamination, it is possible to control the thickness of a molded body by the number of laminated sheets and to produce a substrate having partially different physical properties by changing the composition of the laminated sheets.

FIG. 4 shows a method of manufacturing an oxidizer electrode 301 of a hollow flat substrate by laminating ceramic sheets. Here, a flat laminate 3011 and a strip laminate 3012 are prepared from a sheet laminate that has been thermocompressed in advance, and the strip laminates 3012 arranged at regular intervals are combined with the flat laminate 3.
011 and a method of crimping from above and below.

[0010]

However, when the oxidizer electrode 301 of the hollow flat substrate is manufactured by this method, the sheet containing the binder is softened when the sheet laminate is thermocompression-bonded. The gas flow path in the hollow portion between the bodies 3012 is easily broken, and the pressure needs to be adjusted. On the other hand, if the pressure is too weak, the sheets do not adhere sufficiently to each other, which may cause peeling of the sheet during firing or cracking of the substrate itself. As described above, when a hollow substrate is produced by laminating ceramic sheets, it is necessary to sufficiently press the sheet laminate without crushing the hollow portion of the substrate. Was difficult.

[0011] The present invention has been made in view of the above circumstances, and when a sheet molded body is laminated and crimped in the production of a hollow flat substrate having a gas flow path therein, constituting a single cell of an SOFC. It is another object of the present invention to provide a method of manufacturing an electrode substrate in which sheets are satisfactorily adhered to each other without crushing a hollow portion and as a result, the strength of a hollow flat molded body is improved.

[0012]

In order to achieve the above object, a method of manufacturing an electrode substrate according to the present invention comprises a method of sandwiching a rod-like body in a laminate of ceramic sheets used for an electrode material of a solid oxide fuel cell. After the ceramic sheet was thermocompression-bonded, the rod-shaped body was removed to form a hollow flat substrate , and the hollow flat substrate was degreased.
Thereafter, firing is performed.

Further, the method of manufacturing an electrode substrate according to the present invention is characterized in that a cylindrical rod is used as the rod.

Further, the method of manufacturing an electrode substrate according to the present invention is characterized in that a rod-shaped body to which a lubricant has been applied in advance is used as the rod-shaped body.

[0015]

According to the above-described means, the present invention provides a method for producing a hollow substrate by thermocompression bonding a sheet laminate made of a fuel electrode or an oxidant electrode used in a solid oxide fuel cell. It is characterized in that it is arranged in such a manner as to be sandwiched inside the laminated body and is thermocompression-bonded, and thereafter, the rod-shaped body is extracted.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 (a) and 1 (b) show an example of the structure of an oxidizing electrode of a hollow flat substrate manufactured according to the present invention. FIG.
30A and 30B, reference numeral 302 denotes an oxidizer electrode;
Denotes a plate-like laminate made of a sheet laminate which has been thermocompressed in advance, 602 denotes an oxidant gas flow path, and 8 denotes a cylindrical rod. That is, the rods 8 are arranged at predetermined intervals in a flat laminate 3011 made of a laminate of ceramic sheets used as an electrode material of a solid oxide fuel cell, and the flat laminate 3011 is heated. After the pressure bonding, the rod-shaped body 8 is extracted, so that the oxidizer electrode 30 of the hollow flat substrate is removed.
Form 2 The cross-sectional shape of the gas flow path 602 of the oxidant electrode 302 of the hollow flat substrate differs depending on the shape of the rod 8 used at this time. When a cylindrical rod-shaped body 8 is used as shown in FIG. 1A, the sheet can be pulled out while rotating when the sheet is pressed after being pressed. Alternatively, a rod-shaped body having a different thickness in the length direction may be used, and the rod-shaped body may be pulled out from the thicker one. Even a shape other than the columnar shape can be used by applying a lubricant to the rod in advance so as to reduce friction when removing the rod. That is, in the present embodiment, in the production of the oxidant electrode 302 of the hollow flat substrate, what is sandwiched at the time of thermocompression bonding of the sheet laminate may be a rod, and the cross-sectional shape thereof is not limited.

In the above embodiment, the production of the oxidant electrode 302 was described as a hollow plate-like substrate. However, a fuel electrode may be produced as a hollow plate-like substrate.

Hereinafter, specific examples of the present invention will be described in detail, but the present invention is not limited to the following specific examples.

There are two possible electrode materials for the SOFC, an oxidant electrode and a fuel electrode. An example using an oxidant electrode material will be described below. As an oxidizer electrode material, a conductive ceramic having a perovskite type crystal structure, La _1-x Sr _x, which is generally used as an oxidizer electrode of an SOFC
MnO ₃ (0 ≦ _X ≦ 0.5) having a particle size of 1 μm was used. PVB as a binder and a mixed solvent of isopropyl alcohol: toluene = 77: 23 as a dispersion medium were added to the powder, mixed with a ball mill, and defoamed to adjust the viscosity. Next, this slurry was formed into a sheet having a thickness of about 100 μm by a doctor blade method. Two sheets of this sheet were laminated, and two metal rods each having a diameter of 1.2 mm were arranged at intervals of 7 mm on one of the sheets.
Thermocompression bonding was performed at 0 kgf / cm ² for 10 to 20 minutes. After the sheet laminate is sufficiently cooled, the rod-shaped body is extracted to have gas channels at regular intervals, 5 × 5 cm ² , thickness 4 mm
Was manufactured. The molded body was degreased at 400 ° C. and then baked at 1400 ° C. for 5 hours to obtain a hollow flat plate sintered body. As described above, the hollow flat substrate manufactured according to the present example had very good adhesion between sheets, and no peeling or cracking of the sheets due to sintering was observed.

[0021]

As described above, according to the present invention, the SOF
In the formation of the hollow flat electrode substrate used in C, a rod is sandwiched between sheet laminates to prevent the hollow portion from being crushed during thermocompression bonding and to make the sheet sufficiently adhere. Conventionally, in forming a hollow plate-like electrode substrate by a sheet laminating method, a tape-like sheet laminate was sandwiched and pressed by a flat sheet laminate to form a hollow portion of the electrode substrate. Since the hollow portion was crushed, sufficient pressure could not be applied, and it was difficult to ensure the adhesion between the sheets. In the present invention, by disposing a rod-shaped body in the hollow portion, it is possible to prevent the hollow portion from being crushed during thermocompression bonding, and to improve the adhesiveness between the sheets, thereby preventing peeling of the sheet during sintering and cracking of the substrate Thus, the strength of the substrate can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration perspective view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing an example of a conventional flat panel fuel cell.

FIG. 3 is a perspective view showing a conventional thermoelectric battery using a substrate having a gas flow path therein.

FIG. 4 is an exploded perspective view showing the production of a hollow flat electrode substrate by a conventional sheet lamination method.

[Explanation of symbols]

 1,101 ... electrolyte 2,201 ... fuel electrode 3,301,302 ... oxidizer electrode 4,401 ... interconnector 5 ... fuel gas passage 6,601,602 ... oxidant gas passage 7 ... dense membrane 8 ... rod shape Body 3011: Plate-shaped laminate 3012: Strip-shaped laminate

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Daisuke Ikeda 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Katsumi Manabe 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan Telegraph and Telephone Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) H01M 4/86-4/88 H01M 8 / 02,8 / 12

Claims (3)

(57) [Claims] 1. A rod-shaped body is placed in a laminate of ceramic sheets used as an electrode material of a solid oxide fuel cell, and the rod-shaped body is thermocompression-bonded. Form a flat substrate
A method of manufacturing an electrode substrate , comprising: degreased the hollow flat substrate ; 2. The method for manufacturing an electrode substrate according to claim 1, wherein a cylindrical rod is used as the rod. 3. The method for manufacturing an electrode substrate according to claim 1, wherein a rod-shaped body to which a lubricant is applied in advance is used as the rod-shaped body.