JP2005116289A - Solid electrolyte fuel cell - Google Patents

Abstract

The present invention provides a fuel cell and a fuel cell in which the thermal expansion coefficient of a support is brought close to that of a solid electrolyte and cracks and gas leaks of the fuel cell can be prevented.
A solid electrolyte fuel having a power generation element portion having a layer structure in which an inner electrode, a solid electrolyte, and an outer electrode are sequentially laminated on the surface of an electrically insulating porous support 11 having a gas flow path therein. In the battery cell, the electrically insulating porous support is made of Ni or Ni oxide and calcium zirconate or yttrium oxide, and Ni or Ni oxide is contained in an amount of 10 to 25% by volume in terms of Ni. It is characterized by being.
[Selection] Figure 1

Description

  The present invention relates to a solid electrolyte fuel cell, and more particularly to a solid electrolyte fuel cell having a power generating element portion on the surface of an insulating porous support, a cell stack, and a fuel cell. It is.

  In recent years, various fuel cells in which a cell stack in which a plurality of fuel cells are connected are accommodated in a storage container have been proposed as next-generation energy. Various types of fuel cells such as a solid polymer type, a phosphoric acid type, a molten carbonate type, and a solid electrolyte type are known. Among them, a solid electrolyte type fuel cell has an operating temperature of 800. Although it is as high as ˜1000 ° C., it has advantages such as high power generation efficiency and the ability to use waste heat, and its research and development is being promoted.

  FIG. 9 shows a longitudinal section of a part of a conventionally known horizontal stripe solid electrolyte fuel cell. This solid electrolyte fuel cell includes a power generation element portion 3 having a layer structure in which a fuel electrode 3a, a solid electrolyte 3b, and an air electrode 3c are sequentially laminated on the surface of a cylindrical support 1 that is a porous insulator. The power generation element portions 3 adjacent to each other are connected in series by an interconnector 4, respectively. That is, the fuel electrode 3 a of one power generation element unit 3 and the air electrode 3 c of the other power generation element unit 3 are connected by the interconnector 4. A gas flow path 7 is formed inside the support 1.

  In the horizontal stripe type solid electrolyte fuel cell using the solid electrolyte 3b as the electrolyte, the oxygen ion conductivity of the solid electrolyte 3b is increased from about 600 ° C., so that oxygen is contained in the air electrode 3c in a temperature range of 600 ° C. or higher. By supplying each gas containing hydrogen to the fuel electrode 3a, a potential difference is generated between the air electrode 3c and the fuel electrode 3a based on the oxygen concentration difference between the air electrode 3c and the fuel electrode 3a.

  Oxygen ions that have moved from the air electrode 3c to the fuel electrode 3a through the solid electrolyte 3b are combined with hydrogen ions at the fuel electrode 3a to become water. At this time, electrons move simultaneously. In a fuel cell, by supplying a gas containing oxygen and a gas containing hydrogen, the above reaction is continuously caused to generate electric power. That is, the air electrode 3c generates an electrode reaction of the following formula (1), and the fuel electrode 3a generates an electric power by generating an electrode reaction of the following formula (2).

Air electrode 3c: 1 / 2O ₂ + 2e ⁻ → O ²⁻ (solid electrolyte) (1)
Fuel electrode 3a: O ²⁻ (solid electrolyte) + H ₂ → H ₂ O + 2e ⁻ (2)

  In the horizontally-striped fuel cell, a plurality of power generating element portions 3 that cause the above reaction are formed on the surface of the support 1 in the axial direction and connected in series with each other. There is an advantage that it can be obtained.

In the horizontally striped fuel cell as described above, an insulator must be used for the support 1 in order to prevent an electrical short between the power generating element portions 3, and therefore the support 1 has a solid electrolyte 3b. such ZrO ₂ which was a solid solution of rare earth element oxides used as the coefficient of thermal expansion is dissolved relatively close CaO, etc. completely ZrO ₂ which stabilized are used (see Patent Document 1).
JP 10-003932 A

However, the thermal expansion coefficient of ZrO ₂ in which CaO is solid-solved and completely stabilized is 9.5 × 10 ⁻⁶ / ° C., such as ZrO ₂ in which a rare earth element oxide used as a solid electrolyte is dissolved. For example, the thermal expansion coefficient of ZrO ₂ in which 8 mol of Y ₂ O ₃ is solid-solved is 10.8 × 10 ⁻⁶ / ° C., and the difference in thermal expansion coefficient between the two is 1.0 × 10 ⁻⁶ / ° C. As described above, there are problems such as the solid electrolyte 3b cracking or peeling when the fuel cell is manufactured, when the fuel cell is heated for power generation, or when the fuel cell is cooled as power generation ends. It was.

  Further, when fuel gas (hydrogen gas) is allowed to flow inside the support 1, the support 1 is exposed to a reducing atmosphere. Therefore, even when the reduction treatment is performed, the heat of the support 1 and the solid electrolyte 3 b. Although it is necessary to match the expansion coefficients, the conventionally known support 1 is also required to be improved in this respect.

  Accordingly, the present invention provides a solid electrolyte fuel cell, a cell stack, and a fuel cell that have a reduced thermal expansion coefficient difference between the support that supports the power generation element portion and the solid electrolyte and that are excellent in reliability. Objective.

  According to the present invention, a solid electrolyte type having a power generating element portion having a layer structure in which an inner electrode, a solid electrolyte, and an outer electrode are sequentially laminated on the surface of an electrically insulating porous support having a gas flow path therein. In the fuel battery cell, the electrically insulating porous support is composed of Ni or Ni oxide and a rare earth element oxide, and Ni or Ni oxide is contained in an amount of 10 to 25% by volume in terms of Ni. A fuel cell is provided.

In the fuel battery cell of the present invention,
1. The porous support has a hollow plate-like shape;
2. The porous support has a plurality of gas flow paths therein;
3. A plurality of surfaces are formed on the surface of the porous support, and at least one adjacent power generation element portion is connected in series by an interconnector.
Is preferred.

  In addition, according to the present invention, there is provided a cell stack formed by electrically connecting a plurality of the fuel battery cells to each other through a current collecting member.

  The present invention further provides a fuel cell in which a plurality of the cell stacks are stored in a storage container.

In the present invention, a porous support is formed from Ni or Ni oxide (NiO) and a rare earth element oxide, and the amount of Ni or NiO in terms of Ni is adjusted within a range of 10 to 25% by volume. Thus, the difference in thermal expansion between the porous support and the solid electrolyte can be made less than 1.0 × 10 ⁻⁶ / ° C. That is, since the thermal stress generated due to the difference in thermal expansion between the fuel cell when producing, heating, and cooling can be reduced, cracking and peeling of the solid electrolyte can be suppressed. Moreover, the porous support formed in accordance with the present invention has a remarkably small variation in the coefficient of thermal expansion even after the reduction treatment. Therefore, even in the case where power generation is performed by flowing a fuel gas (hydrogen gas), Thus, the consistency of the thermal expansion coefficient is maintained stably, and the disadvantage caused by the thermal expansion difference can be effectively avoided.

  In addition, by forming the porous support in a hollow plate shape, the area of the power generation element unit per volume of the fuel cell can be increased, and the amount of power generation per fuel cell can be increased, which is necessary. The number of cells for obtaining the amount of power generation can be reduced, and the number of connection points between cells can be reduced. Therefore, the structure and the assembly are simplified and the reliability is improved. In addition, when a cell stack formed by electrically connecting such fuel cells is housed in a storage container to form a fuel cell, the fuel cells can be arranged more densely than a cylindrical fuel cell. Thus, the volume occupied by the cell stack per power generation amount can be reduced, and a small and highly efficient fuel cell can be provided.

  Furthermore, by forming a plurality of gas flow paths inside the porous support, the structural strength of the porous support can be improved, and the strength of the fuel cell can be increased. Therefore, handling of the fuel cell is facilitated, the assembly of the cell stack and the fuel cell is facilitated, and destruction of the fuel cell due to rapid heating and cooling of the fuel cell can be suppressed.

  In the fuel cell of the present invention, a plurality of power generation element portions are formed adjacent to each other on the surface of the porous support (especially in the axial length direction) at predetermined intervals, and the adjacent power generation element portions are connected in series by an interconnector. By connecting to, the generated voltage per fuel cell can be increased.

  FIG. 1 is a longitudinal sectional view of a part of a typical hollow plate-like structure of a fuel cell of the present invention. The fuel cell is arranged on the surface of a hollow plate-like porous support 11 with its axis. A plurality of power generating element portions 13 are arranged adjacent to each other at a predetermined interval in the long direction. FIG. 2 is a cross-sectional view of a hollow plate shape on which the power generation element 13 of FIG. 1 is formed.

  As is clear from FIGS. 1 and 2, the power generation element unit 13 is formed by sequentially laminating the fuel electrode 13a, the solid electrolyte 13b, and the air electrode 13c on the porous support 11, and is adjacent to each other. The power generation element unit 13 is connected in series by an interconnector 14. In other words, the fuel electrode 13 a of one power generation element portion 13 and the air electrode 13 c of the other power generation element portion 13 are electrically connected by the interconnector 14. A plurality of fuel gas passages 12 extend in the axial direction inside the hollow plate-like porous support 11 and are separated by a partition wall 11a (see FIG. 2). By flowing the fuel gas (hydrogen gas) and exposing the air electrode 13c to an oxygen-containing gas such as air, the electrode reaction represented by the above formulas (1) and (2) occurs at the fuel electrode 13a and the air electrode 13c, A potential difference is generated between the two poles to generate electricity.

  The hollow plate-like porous support 11 as described above has a high strength because a plurality of fuel gas passages 12 are provided separated by a partition wall 11a, but its cross section (FIG. 2). The dimension of the flat part n (major axis dimension; corresponding to the distance between the arcuate parts m at both ends) is generally in the range of 15 to 35 mm, and the minor dimension (corresponding to the distance between the two flat parts n). ) Is generally preferably 2 to 4 mm.

In the present invention, it is important that the porous support 11 is made of Ni or Ni oxide (NiO) and a rare earth element oxide. That is, by forming the porous support 11 by combining such components, the thermal expansion coefficient can be brought close to the solid electrolyte 13b described later without impairing the bondability with the power generating element portion 13, For example, the difference in thermal expansion between the two can be made less than 1.0 × 10 ⁻⁶ / ° C., and it is possible to prevent the solid electrolyte 13b from cracking or peeling off during the manufacturing process due to the difference in thermal expansion. It becomes possible. In addition, such a thermal expansion difference is maintained even in a reducing atmosphere. For example, even when hydrogen gas is supplied to the gas flow path 12 to generate power, it is possible to effectively avoid cracking and peeling of the solid electrolyte 13b due to thermal expansion. Can do.

In the present invention, the above-mentioned Ni or NiO (NiO is usually reduced by hydrogen gas and exists as Ni during power generation) is in the range of 10 to 25% by volume, particularly 15 to 20% by volume. 11 should be contained. That is, the porous support 11 needs to be electrically insulative in order to prevent an electrical short circuit between the power generating element portions 13 such as Ni, and usually has no electrical resistance of 10 Ω · cm or more. However, if the content of Ni or the like exceeds the above range, the electrical resistance value is lowered and the electrical insulation is impaired. In addition, if 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 becomes difficult to adjust the thermal expansion coefficient. is there.

Further, all of the remaining amount other than Ni or the like is usually at least one kind of rare earth element oxide, but a small amount, for example, as long as the gist of the present invention that brings the coefficient of thermal expansion close to the solid electrolyte 13b is not impaired. Other oxides or composite oxides such as MgO and SiO ₂ such as calcium zirconate may be contained in the range of 5% by mass or less. Examples of the rare earth element constituting the rare earth element oxide include Y, La, Yb, Tm, Er, Ho, Dy, Gd, Sm, and Pr. ₂ O ₃ and Yb ₂ O ₃ , especially Y ₂ O ₃ .

  Further, the porous support 11 must be capable of introducing the fuel gas in the fuel gas flow path 12 up to the surface of the fuel electrode 13a, and therefore needs to be porous. The open porosity is preferably 25% or more, particularly 30 to 40%.

In the power generation element portion 13, the fuel electrode 13a formed on the surface of the support 11 causes the electrode reaction of the above formula (2), and is formed of a well-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 forming the solid electrolyte 13b described later is preferably used.

  The stabilized zirconia content in the fuel electrode 13a is preferably in the range of 35 to 65% by volume, the content of Ni or the like is preferably in the range of 65 to 35% by volume, and the fuel electrode 13a is opened. The porosity should be in the range of 15% or more, particularly 20 to 40%, and the thickness is preferably 1 to 100 μm in order to exhibit good current collecting performance.

The solid electrolyte 13b has a function as an electrolyte for bridging electrons between the electrodes, and at the same time needs to have a gas barrier property in order to prevent leakage of fuel gas and oxygen-containing gas such as air. It is. Therefore, as the solid electrolyte 13b, it is preferable to use dense ceramics having such characteristics, for example, stabilized ZrO _{2 in} which ₃ to 15 mol% of a rare earth element is dissolved. Examples of rare earth elements in the stabilized ZrO ₂ include Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. However, Y and Yb are preferable because they are inexpensive. A lanthanum gallate solid electrolyte having a thermal expansion coefficient substantially equal to that of 8YSZ (stabilized ZrO ₂ in which 8 mol% of Y is dissolved) can also be suitably used.

  The solid electrolyte 13b preferably has a thickness of 10 to 100 μm from the viewpoint of preventing gas permeation, and has a relative density (according to Archimedes method) of 93% or more, particularly 95% or more.

The air electrode 13c formed on the solid electrolyte 13b causes the electrode reaction of the above-described formula (1), and is formed from a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. As such a perovskite type oxide, at least one of transition metal type perovskite oxides, particularly LaMnO ₃ oxides, LaFeO ₃ oxides, LaCoO ₃ oxides having La at the A site is preferable, and 600 From the viewpoint of high electrical conductivity at a relatively low temperature of about ˜1000 ° C., LaFeO ₃ -based oxides are particularly suitable. In the perovskite oxide, Sr may exist together with La at the A site, and Fe, Co, and Mn may coexist at the B site.

  The air electrode 13c must have gas permeability, and its open porosity is preferably 20% or more, particularly 30 to 50%. Furthermore, the thickness is preferably 30 to 100 μm from the viewpoint of current collection.

The interconnector 14 used for connecting adjacent power generating elements 13 in series connects the fuel electrode 13a of one power generating element part 13 and the air electrode 13c of the other power generating element part 13, Although it is formed from conductive ceramics, 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. For this reason, lanthanum chromite perovskite oxides (LaCrO ₃ oxides) are generally used as the conductive ceramics. Further, in order to prevent leakage of fuel gas passing through the gas flow path 12 in the porous support 11 and oxygen-containing gas such as air passing outside the air electrode 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 interconnector 14 and the end face of the solid electrolyte 13b.

  In the above-described example, the power generating element portion 13 formed on the porous support has a layer structure in which the inner electrode is the fuel electrode 13a and the outer electrode is the air electrode 13c. Of course, the positional relationship between the two electrodes can be reversed. That is, the power generating element portion 13 can be formed by laminating the air electrode 13c, the solid electrolyte 13b, and the fuel electrode 13a in this order on the porous support 11. In this case, an oxygen-containing gas such as air is introduced into the gas flow path 12 of the porous support 11, and the fuel gas is supplied to the outer surface of the fuel electrode 13a that is the outer electrode.

  FIG. 3 shows the fuel cell connection structure described above, and a dense cell connection member 15 that is electrically connected to the fuel electrode 13a is provided at one end of the fuel cell, and this cell connection member. 15 is connected to the air electrode 13 c of the power generation element portion 13 formed at the end of the other fuel battery cell via the current collecting member 19. Since the cell connection material 15 is required to have the same function as the interconnector 14, it is formed of the same material as the interconnector 14.

  The current collecting member 19 for connecting the cell connecting material 15 and the air electrode 13c of another fuel battery cell is generally formed from a heat-resistant metal plate or an inorganic material used as an air electrode material. Connection reliability can be improved by using, as a conductive adhesive, a paste containing a noble metal such as Ag or Pt at a connection portion between 19 and the cell connection member 15 or the air electrode 13c. In addition, when the fuel electrode 13a is formed on the outer surface side of the power generation element unit 13, Ni felt is preferably used as the current collecting member 19, and Ni metal is used as the conductive adhesive. The paste contained is inexpensive and suitable.

  When joining a plurality of fuel cells, as shown in FIG. 3, the end portions of one cell and the end portion of the other cell have different structures and are sequentially connected alternately.

  As shown in FIG. 4, the cell stack assembled using the fuel cell described above includes a cell connecting material 15 at the end of one fuel cell and an air electrode 13 c at the end of the other fuel cell. A current collecting member 19 made of a metal felt and / or a heat-resistant metal plate, an inorganic material used as an air electrode material is interposed therebetween, and a fuel electrode 13a formed on the support 11 of one of the fuel cells, It is configured to be electrically connected to the air electrode 13c of the other fuel cell through the dense cell connecting material 15 and the current collecting member 19. In FIG. 4, the power generation element 13, the interconnector 14, and the cell connection material 15 are illustrated in a simplified manner.

  The current collecting member 19 is preferably made of at least one of Pt, Ag, Ni-base alloy, and Fe—Cr steel alloy from the viewpoint of heat resistance, oxidation resistance, and electrical conductivity. Further, in FIG. 4, reference numeral 21 denotes a conductive member for electrically connecting the cell stack and another cell stack, and a conductive member for taking out the electric power generated in the cell stack outside the fuel cell. .

  The fuel cell of the present invention is configured by accommodating the cell stack of FIG. 4 in a storage container. The storage container is provided with an introduction pipe for introducing a fuel gas such as hydrogen and an oxygen-containing gas such as air from the outside into the fuel cell, and generates electricity when the fuel cell is heated to a predetermined temperature. The used fuel gas and oxygen-containing gas are discharged out of the storage container. In such a fuel cell, the voltage can be easily increased, and a short circuit between the power generation element portions 13 and a change in the structure of the support 11 due to heat can be suppressed.

  In the present invention, the fuel cell described above can be manufactured, for example, as follows.

First, as a support material, a rare earth element oxide powder such as a Y ₂ O ₃ powder having an average particle diameter of 0.1 to 10 μm and a Ni powder (or a NiO powder) are prepared. The thermal expansion coefficient after mixing is made to substantially match that of the solid electrolyte 13b. The mixed powder is mixed with a pore agent, a cellulose organic binder, and a solvent composed of water, extruded, and formed into a hollow plate having a fuel gas channel 52 inside as shown in FIG. The shape, that is, a cylindrical or flat support molded body 51 is produced, dried, and calcined at 900 ° C. to 1100 ° C.

Next, a fuel electrode material and a solid electrolyte material are formed.
For example, NiO powder, Ni powder, and ZrO ₂ powder in which a rare earth element oxide such as Y ₂ O ₃ is dissolved, are mixed with a pore agent, an acrylic binder and toluene are added to form a slurry, As shown in FIG. 6A, a fuel electrode tape 53a having a thickness of 50 to 60 μm is produced by a doctor blade method.

On the other hand, an acrylic binder and toluene are added to 8YSZ (ZrO ₂ powder in which 8 mol% of Y is solid-dissolved) to form a slurry. As shown in FIG. 6A, the thickness is 10 to 50 μm by a doctor blade method. The solid electrolyte tape 53b is prepared.

  Next, as shown in FIG. 6B, the fuel electrode tape 53a and the solid electrolyte tape 53b are overlapped so that the portions where they do not overlap each other can be 1 to 5 mm, respectively. After bonding, as shown in FIG. 7A, the fuel electrode tape 53a side is attached to the calcined support molded body 51 in a horizontal stripe pattern as shown in FIG. At this time, a laminated body of a plurality of fuel electrode tapes 53a and solid electrolyte tape 53b is affixed on the calcined support body molded body 51. The laminated body of the fuel electrode tape 53a and solid electrolyte tape 53b at that time Further, the other fuel electrode tape 53a and the laminated body of the solid electrolyte tape 53b are arranged with an interval of 3 to 20 mm. Next, this laminate is dried and calcined in a temperature range of 900 to 1100 ° C.

  Next, the interconnector molded body 54 and the cell connection material molded body 59 are formed. Since the same material can be used for the interconnector 14 and the cell connecting material 15, both are formed in the same process here.

  For example, a dip slurry is prepared with lanthanum chromite and a PVA binder.

  Next, as shown in FIG. 7 (a), the calcined body of the solid electrolyte tape 53b is the calcined body of the laminated body of the support body 51, the fuel electrode tape 53a, and the solid electrolyte tape 53b produced previously. The part excluding a part of the body is covered with a masking tape 61, and then dipped with a dip slurry to form an interconnector molded body 54 and a cell connecting material molded body 59 as shown in FIG. . Then, after drying and removing the masking tape 61 as shown in FIG.7 (c), it baked at 1450-1550 degreeC, the interconnector 14 and the cell connection material 15 are 2 in the edge part of the solid electrolyte 13b. Approximately 5mm overlap.

  Next, as shown in FIG. 8A, with the masking tape 63 except for the entire surface of the cell connecting material 15 and a part of the interconnector 14 on the side where the interconnector 14 is not connected to the fuel electrode tape 13a. Mask.

  Further, as shown in FIG. 8B, for example, a slurry obtained by mixing lanthanum cobaltite and isopropyl alcohol is sprayed onto the masked laminate to form an air electrode molded body 53c having a thickness of 10 to 100 μm. To do. Thereafter, as shown in FIG. 8C, the masking tape 63 is removed, and then a heat treatment is performed at 1000 ° C. to 1200 ° C., thereby obtaining a fuel cell having a target structure.

  Here, tape lamination, dipping, and spraying are performed together, but any molding method may be used as long as the gist of the present invention is not changed. In particular, the tape laminating method, unlike dip, requires a short drying process at the time of laminating. Therefore, it is preferable to tape-mold and laminate the above-mentioned members to shorten the process.

  Note that the fuel battery cell is baked in an oxygen-containing atmosphere. For example, when the support 11 contains Ni, the Ni component of the support 11 and the fuel electrode 13a is NiO. Since it is treated or exposed to a reducing atmosphere during power generation, it is reduced at this time.

  In the above example, the porous support 11 is described as a hollow plate having a plurality of gas flow paths 12 inside. However, the porous support 11 may be cylindrical, and the gas flow path 12 It goes without saying that the number of can be one.

  First, yttrium oxide powder having an average particle diameter of 0.1 to 10 μm and NiO powder having an average sphere diameter of 0.1 to 5 μm were mixed so as to have the ratio shown in Table 1. A support material formed by mixing these mixtures with a pore agent having an average particle size of 30 μm, an organic binder made of PVA, and a solvent made of water is extruded, and as shown in FIG. A columnar support body 51 having a fuel gas flow path 52 and a flat cross section was produced, dried, and calcined at 1050 ° C.

  Further, a solid electrolyte tape 53b having a thickness of 35 μm was produced by a doctor blade method from a slurry obtained by adding an acrylic binder and toluene to an 8YSZ raw material having an average particle diameter of 0.5 μm.

  Next, NiO powder with an average particle size of 0.5 μm, or Ni powder with an average particle size of 0.5 μm, 8YSZ powder with an average particle size of 0.5 μm, the ratio of metal Ni to 8YSZ is 50:50 in volume ratio. Then, a pore agent is added to the mixture, and an acrylic binder and toluene are added to form a slurry. As shown in FIG. 6, a fuel electrode tape 53a having a thickness of about 50 μm is formed by a doctor blade method. Was made.

These fuel electrode tapes 53a and 8YSZ-based solid electrolyte tape 53b are overlapped so that the portions where they do not overlap each other are 3 mm, and are bonded together at a pressure of ² ton / cm ² , and then the fuel electrode tape 53a side is attached. The support molded body 51 was pasted on the calcined body in a horizontal stripe pattern. At this time, as shown in FIG. 7, a plurality of fuel electrode tapes 53a and a laminated tape of a solid electrolyte tape 53b are affixed on the calcined body of the support molded body 51. The laminated tape of the solid electrolyte tape 53b, the other adjacent fuel electrode tape 53a, and the laminated tape of the electrolyte tape 53b were arranged at an interval of 10 mm. Thereafter, this laminate was dried and calcined at 1050 ° C.

  Next, an interconnector molded body 54 and a cell connection material molded body 59 were formed. First, a slurry for dip is prepared with lanthanum chromite having an average particle diameter of 0.8 μm and a PVA-based binder, and then the fuel electrode tape 53a and the laminated tape of the solid electrolyte tape 53b are formed into a support body. The portion of the calcined body placed on 51 excluding a part of the calcined body of the solid electrolyte tape 53b is covered with a masking tape 61, and then dipped with a dip slurry to connect the interconnector molded body 54 to the cell. A material molded body 59 was molded. At this time, the interconnector molded body 54 and the cell connection material molded body 59 are overlapped by about 3 mm from the end of the calcined body of the solid electrolyte tape 53b, and then dried and the masking tape 61 is removed. Baked in.

  Next, as shown in FIG. 8, an air electrode molded body 53c was formed. First, the entire surface of the sintered body of the cell connection material molded body 59 and the portion of the sintered body of the interconnector molded body 54 excluding a part on the side not connected to the sintered body of the fuel electrode tape 53a, Masking tape 63 is used for masking, and then a slurry obtained by mixing lanthanum cobalt with an average particle size of 0.7 μm and isopropyl alcohol is sprayed on the masked laminate to form an air electrode having a thickness of 20 μm. The body 53c was molded. Thereafter, the masking tape 63 was removed, and then the treatment was performed at 1100 ° C. to produce a fuel cell as shown in FIG.

  The support 11 has an elliptical cross section, the major axis is 26 mm, the minor axis is 3.5 mm, the thickness of the fuel electrode 13 a is 40 μm, the thickness of the solid electrolyte 13 b is 30 μm, the thickness of the air electrode 13 c is 40 μm, and the interconnector. 14 and the thickness of the cell connecting material 15 was 100 μm. The cell length was 150 mm.

  As a fuel gas, hydrogen gas is caused to flow in the gas flow path 12 of the obtained support 11 of the fuel cell, and air is caused to flow toward the air electrode 13c. Then, after generating power for 100 hours and cooling, a microscopic inspection and a gas leak test were performed.

  The gas leak test is performed by sealing one side of the gas flow path 12 of the fuel battery cell, introducing 1 atm of He gas into the gas flow path 12 from the other end, immersing the fuel battery cell in water, The presence or absence of gas leakage was judged by the presence or absence.

  Moreover, the test piece for a thermal expansion coefficient measurement was cut out from the support body 11 of the produced fuel cell, and the thermal expansion coefficient of 25-1000 degreeC was measured.

Table 1 describes the contents of the yttrium oxide powder and NiO powder used for the support 11, the thermal expansion coefficient of the support 11, the presence or absence of conduction, the cracks in the fuel cell after the 850 × 100 hour power generation test, and the presence or absence of gas leaks. did.

Sample No. of the present invention. In each of 1-4, the difference in thermal expansion from the solid electrolyte 13b is less than 1 × 10 ⁻⁶ , there are no cracks and no gas leak, and the reliability of the fuel cell is remarkably improved.

  Furthermore, sample no. In No. 5, the support 11 was found to be electrically conductive and did not function as a fuel cell.

It is a longitudinal cross-sectional view which expands and shows a part of fuel cell of this invention. It is a cross-sectional view of FIG. It is a longitudinal cross-sectional view which expands and shows the edge part connection structure of the fuel battery cell of this invention. It is a longitudinal cross-sectional view which shows the cell stack of the fuel battery cell of this invention. It is a longitudinal cross-sectional view which shows the manufacturing process of the support body of the fuel cell of this invention. It is a longitudinal cross-sectional view which shows the manufacturing process of the electric power generation element part of the fuel battery cell of this invention. It is a longitudinal cross-sectional view which shows the formation process of the interconnector which electrically connects between the electric power generation element parts of the fuel battery cell of this invention. It is a longitudinal cross-sectional view which shows the formation process of the air electrode of the fuel battery cell of this invention. It is a longitudinal cross-sectional view which expands and shows a part of conventional horizontal stripe-shaped fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Porous support body 12 ... Fuel gas flow path 13 ... Power generation element 13a ... Fuel electrode 13b ... Solid electrolyte 13c ... Air electrode 14 ... Interconnector

Claims (6)

  In the solid oxide fuel cell having a power generation element portion having a layer structure in which an inner electrode, a solid electrolyte and an outer electrode are sequentially laminated on the surface of an electrically insulating porous support having a gas flow path therein, The electrically insulating porous support is made of Ni or Ni oxide and a rare earth element oxide, and Ni or Ni oxide is contained in an amount of 10 to 25% by volume in terms of Ni. Fuel cell.   The fuel cell according to claim 1, wherein the porous support has a hollow plate shape.   The fuel cell according to claim 1, wherein the porous support has a plurality of gas flow paths therein.   2. A plurality of the power generation element portions are formed adjacent to each other on the surface of the porous support, and at least one adjacent power generation element portion is electrically connected in series by an interconnector. The fuel battery cell according to any one of 1 to 3.   A cell stack formed by electrically connecting a plurality of fuel cells according to any one of claims 1 to 4 through a current collecting member.   A fuel cell comprising a plurality of the cell stacks according to claim 5 stored in a storage container.

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