JP4502665B2 - Method for manufacturing rod-shaped body and method for manufacturing rod-shaped fuel cell - Google Patents

Description

The present invention relates to a manufacturing method of preparation and the rod-shaped fuel cell cell Le bar-like body on the surface of the porous body having a coated fabric layer.

  In recent years, various fuel cells in which a stack of fuel cells is accommodated in a storage container have been proposed as next-generation energy.

Figure 5 shows a cell stack of a conventional solid electrolyte fuel cell, the cell stack is aligned set a plurality of fuel cells 1, one of the fuel cell 1a adjacent the other of the fuel cell 1b A current collecting member 5 made of metal felt is interposed between the fuel electrode 7 of one fuel cell 1a and an oxygen electrode (air electrode) 11 of the other fuel cell 1b. It had been.

  In the fuel cell 1 (1a, 1b), a solid electrolyte 9 and an oxygen electrode 11 made of conductive ceramics are sequentially provided on the outer peripheral surface of a fuel electrode 7 (having a fuel gas passage inside) made of a cylindrical cermet. An interconnector 13 is provided on the surface of the fuel electrode 7 that is configured and is not covered with the solid electrolyte 9 or the oxygen electrode 11. As apparent from FIG. 5, the interconnector 13 is electrically connected to the fuel electrode 7 so as not to be connected to the oxygen electrode 11.

  The interconnector 13 is formed of conductive ceramics that are not easily altered by oxygen-containing gas such as fuel gas and air. The conductive ceramics are disposed between the fuel gas flowing inside the fuel electrode 7 and the outside of the oxygen electrode 11. It must be dense to ensure that it shuts off the flowing oxygen-containing gas.

  The current collecting member 5 provided between the adjacent fuel cells 1a, 1b is electrically connected to the fuel electrode 7 of one fuel cell 1a via the interconnector 13, and the other fuel cell. It is connected to the oxygen electrode 11 of the cell 1b, so that adjacent fuel cells are connected in series.

  The fuel cell is configured by accommodating a cell stack having the above structure in a storage container, and a fuel gas (hydrogen) is allowed to flow inside the fuel electrode 7 and an air (oxygen) is allowed to flow to the oxygen electrode 11 at about 1000 ° C. It generates electricity.

In the fuel cell constituting the fuel cell described above, generally, the fuel electrode 7 is formed of Ni and ZrO ₂ (YSZ) containing Y ₂ O ₃ , and the solid electrolyte 9 contains Y ₂ O ₃ . It is formed from ZrO 2 _(YSZ) for the oxygen electrode 11 is composed of a perovskite-type composite oxide of lanthanum manganate system.

As a method for producing such a fuel battery cell, for example, it is known to form a solid electrolyte by a dip coating method (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 5-198305

  However, in a conventional fuel cell, although it is described that a cylindrical fuel electrode is immersed in an immersion liquid containing a solid electrolyte material to form a solid electrolyte on the surface of the fuel electrode, in general, A method of immersing a cylindrical fuel electrode in the longitudinal direction in the immersion liquid as shown in FIG. 4 is employed. In this case, the immersion time differs at both ends in the longitudinal direction. There is a problem that the thickness of the solid electrolyte in the first immersion portion is larger than the thickness of the solid electrolyte in the last immersion portion, and the thickness variation of the solid electrolyte in the length direction is large. Further, in order to improve the film forming speed, air inside the fuel electrode is sucked to make a negative pressure. However, in this case, there is a problem that the variation in thickness of the solid electrolyte is further increased. In FIG. 4, reference numeral 21 denotes a porous body, 23 denotes an immersion liquid, and 24 denotes a suction device.

The present invention aims at providing a manufacturing method of preparation and the rod-shaped fuel cell cell Le bar-like member which can reduce the thickness difference of the coating film in the length direction of the porous body.

Preparation of rod-shaped body of the present invention, the immersion fluid in which a plurality of gas passages therein a porous body like a long formed in the longitudinal direction, comprising a coating film material from the side of the one in the longitudinal direction The gas passage that is immersed last is sucked with a larger suction force than the gas passage that is immersed first . In such a manufacturing method of the rod-shaped body, since the width direction is immersed from one side along the longitudinal direction of the porous body, the difference in immersion time is smaller than the case of immersion in the length direction. The film thickness difference can be made smaller than before .

Furthermore, preparation of the rod-shaped body of the present invention, in the gas passage on the side at the end immersed, characterized by suction at greater suction force than the gas passage on the side which is immersed in the first. In this case, the difference in immersion time is small, and even a slight difference in immersion time can be adjusted by the suction pressure of the gas passage, so that the difference in thickness of the coating film can be substantially eliminated.

The method for producing a rod-shaped fuel cell according to the present invention includes a rod-shaped fuel in which an inner porous electrode, a solid electrolyte, and an outer porous electrode are sequentially formed on a porous support having a plurality of gas passages formed in the longitudinal direction therein. A method for producing a battery cell, wherein the porous support is immersed in an immersion liquid containing an inner porous electrode material from one side along the longitudinal direction, and finally immersed in the gas passage. Is sucked with a larger suction force than in the gas passage immersed first.

The method for manufacturing a rod-shaped fuel cell according to the present invention is a method for manufacturing a rod-shaped fuel cell in which an inner porous electrode, a solid electrolyte, and an outer porous electrode are sequentially formed, and a plurality of gas passages are formed in the longitudinal direction. A long porous support body having a plurality of gas passages formed longitudinally therein and having an inner porous electrode on the surface, on one side along the longitudinal direction. It is soaked in an immersion liquid containing a solid electrolyte material from the side, and the gas path to be immersed last is sucked with a suction force larger than that in the gas path to be immersed first. . In such a method for manufacturing a rod-shaped fuel cell, a thin solid electrolyte layer with a uniform film thickness can be formed.

Also, preparation of rod-shaped fuel cell of the present invention, in the gas passage on the side at the end immersed, characterized by suction at greater suction force than the gas passage on the side which is immersed in The first . In such a method for manufacturing a rod-shaped fuel battery cell, variations in the immersion direction of the formed film thickness can be reduced.

In the rod-shaped fuel cell produced by the method for producing the rod-shaped fuel cell of the present invention, the fuel electrode layer and the solid electrolyte layer can be formed to be thin and uniform in thickness, thereby providing a high-power and highly reliable rod-shaped fuel. A battery cell can be obtained.

In FIG. 1 which shows the cross section of the rod-shaped fuel cell produced by the manufacturing method of the rod-shaped fuel cell of this invention, the fuel cell (hollow flat plate type) shown as 30 as a whole has a flat cross section and is entirely A support substrate 31 having an elongated substrate shape is provided. Inside the support substrate 31, a plurality of fuel gas passages 31 a are formed penetrating in the length direction at appropriate intervals. The fuel cell 30 is provided with various members on the support substrate 31. It has a structure. A plurality of such fuel cells 30 are connected to each other in series by a current collecting member 40 as shown in FIG. 2, thereby forming a cell stack constituting the fuel cell.

  As understood from the shape shown in FIG. 1, the support substrate 31 includes a flat portion A and arc-shaped portions B at both ends of the flat portion A. Both surfaces of the flat portion A are formed substantially parallel to each other, and a fuel electrode layer 32 is provided so as to cover one surface of the flat portion A and the arc-shaped portions B on both sides. A dense solid electrolyte layer 33 is laminated so as to cover, and an oxygen electrode 34 is laminated on one surface of the flat portion A so as to face the fuel electrode layer 32 on the solid electrolyte layer 33. Has been.

  An interconnector 35 is formed on the other surface of the flat portion A where the fuel electrode layer 32 and the solid electrode layer 33 are not stacked. As is clear from FIG. 1, the fuel electrode layer 32 and the solid electrolyte layer 33 extend to both sides of the interconnector 35 and are configured so that the surface of the support substrate 31 is not exposed to the outside.

  In the fuel cell having the above structure, the portion of the fuel electrode layer 32 facing the oxygen electrode 34 operates as a fuel electrode to generate electric power. That is, an oxygen-containing gas such as air is allowed to flow outside the oxygen electrode 34, and a fuel gas (hydrogen) is allowed to flow through the gas passage 31a in the support substrate 31 and heated to a predetermined operating temperature. Electricity is generated by generating an electrode reaction of the formula (1) and generating an electrode reaction of the following formula (2), for example, in the portion of the fuel electrode layer 32 that becomes the fuel electrode.

Oxygen electrode: 1 / 2O ₂ + 2e ⁻ → O ²⁻ (solid electrolyte) (1)
Fuel electrode: O ²⁻ (solid electrolyte) + H ₂ → H ₂ O + 2e ⁻ (2)
The current generated by the power generation is collected through the interconnector 35 attached to the support substrate 31.

(Support substrate)
In the fuel cell 30 having the above-described structure, the support substrate 31 is gas permeable so as to allow the fuel gas to permeate to the fuel electrode, and conductive for collecting current via the interconnector 35. In order to satisfy such requirements, support from iron group metal components and rare earth element oxides is required. A substrate 31 is formed.

  The iron group metal component is for imparting conductivity to the support substrate 31 and may be a single iron group metal, or an iron group metal oxide, an iron group metal alloy or an alloy oxide. May be. The iron group metals include iron, nickel, and cobalt. In the present invention, any of them can be used, but it contains Ni and / or NiO because it is inexpensive and stable in fuel gas. It is preferable.

The rare earth element oxide is used to approximate the thermal expansion coefficient of the support substrate 31 to the stabilized zirconia or lanthanum gallate perovskite composition forming the solid electrolyte layer 33. In particular, Y ₂ O ₃ is desirable as the rare earth element oxide. In particular, the iron group component described above is included in the support substrate 31 in an amount of 35 to 65% by volume in terms of approximating the thermal expansion coefficient of the support substrate 31 to that of a solid electrolyte material such as stabilized zirconia. The object is preferably contained in the support substrate 31 in an amount of 35 to 65% by volume.

  The support substrate 31 may contain other metal components and oxide components as long as required characteristics are not impaired.

  Since the support substrate 31 as described above is required to have fuel gas permeability, it is usually preferable that the open porosity is in the range of 30% or more, particularly 35 to 50%. Further, the conductivity of the support substrate 31 is preferably 300 S / cm or more, and particularly preferably 440 S / cm or more.

  Further, the length of the flat portion A of the support substrate 31 is normally 15 to 35 mm, the length of the arc-shaped portion B (the length of the arc) is about 3 to 8 mm, and the thickness of the support substrate 31 is (flat portion). The distance between both surfaces of A) is preferably about 2.5 to 5 mm.

(Fuel electrode layer)
Retardant Ryokyokuso 32, it is necessary to have a fuel gas permeability, which allowed to rise to electrode reaction expressed by the aforementioned equations (2), formed from a per se known porous conductive ceramic Is done. For example, it is formed from ZrO ₂ in which a rare earth element is dissolved, and Ni and / or NiO. As ZrO ₂ (stabilized zirconia) in which the rare earth element is dissolved, the same one used for forming the solid electrolyte layer 33 described below is preferably used.

  The stabilized zirconia content in the fuel electrode layer 32 is preferably in the range of 35 to 65% by volume, and the Ni or NiO content is preferably 65 to 35% by volume. Furthermore, the open porosity of the fuel electrode layer 32 is preferably 15% or more, particularly in the range of 20 to 40%, and the thickness thereof is improved between the performance and the solid electrolyte layer 33 and the fuel electrode layer 32. In order to prevent peeling due to the difference in thermal expansion, it is desirable that the thickness is 1 to 30 μm.

Further, in the example of FIG. 1, the fuel electrode layer 32 extends to both sides of the interconnector 35, but it is sufficient that the fuel electrode is formed at a position facing the oxygen electrode 34. For example, the fuel electrode layer 32 may be formed only in the flat portion A on the side where the oxygen electrode 34 is provided. Furthermore, the fuel electrode layer 32 can be formed over the entire circumference of the support substrate 31 . To increase the bonding strength between the solid body electrolyte layer 33 and the support substrate 31, it is preferable that the whole of the solid electrolyte layer 33 is formed on the fuel electrode layer 32.

(Solid electrolyte layer)
The solid electrolyte layer 33 provided on the fuel electrode layer 32 is generally formed of a dense ceramic called ZrO ₂ (usually stabilized zirconia) in which 3 to 15 mol% of a rare earth element is dissolved. . Examples of rare earth elements include Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, but they are inexpensive. From the point, Y and Yb are desirable.

  The stabilized zirconia ceramics forming the solid electrolyte layer 33 is desirably a dense material having a relative density (according to Archimedes method) of 93% or more, particularly 95% or more from the viewpoint of preventing gas permeation. It is desirable that the thickness is 10 to 100 μm. The solid electrolyte layer 3 may be composed of a lanthanum gallate perovskite type composition in addition to the stabilized zirconia.

(Oxygen electrode)
The oxygen electrode 34 is formed of a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. As such a perovskite oxide, at least one of transition metal perovskite oxides, particularly LaMnO ₃ oxides, LaFeO ₃ oxides, and LaCoO ₃ oxides having La at the A site is preferable. LaFeO ₃ -based oxides are particularly suitable because they have high electrical conductivity at an operating temperature of about 1000 ° C. In the perovskite oxide, Sr and the like may exist together with La at the A site, and Co and Mn may exist together with Fe at the B site.

  The oxygen electrode 34 must have gas permeability. Therefore, the conductive ceramic (perovskite oxide) forming the oxygen electrode 34 has an open porosity of 20% or more, particularly 30 to 50. It is desirable to be in the range of%.

  The thickness of the oxygen electrode 34 is preferably 30 to 100 μm from the viewpoint of current collection.

(Interconnector)
The interconnector provided on the support substrate 31 at the position facing the oxygen electrode 34 is made of conductive ceramics, but comes in contact with the fuel gas (hydrogen) and the oxygen-containing gas. It is necessary to have chemical properties. For this reason, lanthanum chromite perovskite oxides (LaCrO ₃ oxides) are generally used as the conductive ceramics. Further, in order to prevent leakage of the fuel gas passing through the inside of the support substrate 31 and the oxygen-containing gas passing through the outside of the support substrate 31, such conductive ceramics must be dense, for example, 93% or more, particularly 95%. It is preferable to have the above relative density.

  The interconnector 35 is desirably 10 to 200 μm from the viewpoint of preventing gas leakage and electrical resistance.

Further, as is clear from FIG. 1, in order to prevent gas leakage, a dense solid electrolyte layer 33 is in close contact with both sides of the interconnector 35. _A sealing layer (not shown) made of ₂ O ₃ or the like can be provided between both side surfaces of the interconnector 35 and the solid electrolyte layer 33.

(Diffusion prevention layer)
A diffusion prevention layer 36 is formed between the solid electrolyte 33 and the oxygen electrode 34. The anti-diffusion layer 36 _is a _{(CeO 2) 1-x (} SmO 1.5) x (0 <x ≦ 0.3) composite oxide formula Sm represented by consists of CeO ₂ was dissolved in It is preferable. In particular, from the viewpoint of reducing electrical resistance, x in the general formula is preferably made of CeO ₂ in which Sm having a composition represented by 0.1 ≦ x ≦ 0.2 is dissolved. Further, in order to increase the effect of blocking or suppressing the diffusion, another rare earth element oxide may be contained.

(P-type semiconductor layer 39)
A P-type semiconductor layer 39 is preferably provided on the outer surface (upper surface) of the interconnector 35. That is, in the cell stack assembled from the fuel cells (see FIG. 2), the conductive current collecting member 40 is connected to the interconnector 35, but when the current collecting member 40 is directly connected to the interconnector 35, By non-ohmic contact, the potential drop becomes large, and the current collecting performance deteriorates.

  However, by connecting the current collecting member 40 to the interconnector 35 via the P-type semiconductor layer 39, the contact between the two becomes an ohmic contact, the potential drop is reduced, and the deterioration of the current collecting performance is effectively avoided. For example, the current from the oxygen electrode 34 of one fuel cell 30 can be efficiently transmitted to the support substrate 31 of the other fuel cell 30. As such a P-type semiconductor, a transition metal perovskite oxide can be exemplified.

Specifically, those having higher electronic conductivity than LaCrO ₃ oxides constituting the interconnector, such as LaMnO ₃ oxides, LaFeO ₃ oxides in which Mn, Fe, Co, etc. exist at the B site, P-type semiconductor ceramics made of at least one of LaCoO ₃ -based oxides can be used. In general, the thickness of the P-type semiconductor layer 39 is preferably in the range of 30 to 100 μm.

  The interconnector 35 can also be provided directly on the flat portion A of the support substrate 31 on the side where the solid electrolyte layer 33 is not provided. The fuel electrode layer 32 is also provided in this portion, and this fuel electrode layer 32 is provided. An interconnector can also be provided on the top. That is, the fuel electrode layer 32 can be provided over the entire circumference of the support substrate 31, and the interconnector can be provided on the fuel electrode layer 32.

(Manufacture of fuel cells)
The fuel battery cell having the above structure is manufactured as follows.

First, an iron group metal such as Ni or its oxide powder, for example, Y ₂ O ₃ powder, an organic binder, and a solvent are mixed to prepare a slurry, and the long length is obtained by extrusion molding using this slurry. A support substrate molded body having a rod shape is prepared and dried.

  Next, a fuel electrode layer forming material (Ni or NiO powder and stabilized zirconia powder), an organic binder, and a solvent are mixed to prepare a slurry, and a sheet for the fuel electrode layer is prepared using this slurry. Further, instead of producing a sheet for the fuel electrode layer, a paste in which the fuel electrode forming material is dispersed in a solvent is applied to a predetermined position of the formed support substrate and dried, and then the fuel electrode layer is formed. A coating layer may be formed. Then, the sheet | seat or coating layer for fuel electrode layers formed in the surface of a support substrate molded object is calcined with a support substrate molded object at 800-1100 degreeC. The calcined support substrate calcined body and fuel layer calcined body are porous.

Then, a solid electrolyte molded body is formed on the calcined body of the fuel electrode layer. First, a solid electrolyte material, for example, a ZrO ₂ powder in which 3 to 15 mol% of a rare earth element is dissolved, an organic binder, and a solvent are mixed to prepare an immersion liquid. As shown in FIG. during the immersion liquid 53, the support substrate calcined body 55 calcined body of the fuel electrode layer is formed, on its side, in other words, is immersed from the side of the supporting substrate calcined body 55. In other words, the support substrate calcined body 55 is dipped from one arcuate part B to the other arcuate part B. As a result, as shown in FIG. 4, since the difference in immersion time is smaller than in the case of immersion in the length direction of the support substrate calcined body 55, the difference in film thickness at both ends in the length direction of the coating film of the solid electrolyte material is reduced. 5 μm or less. In addition, it masks beforehand in the part which does not form the coating film of solid electrolyte material.

  Further, when the air in the gas passages of the support substrate calcined body is sucked to a negative pressure lower than the atmospheric pressure, the solid electrolyte coating film can be formed efficiently. FIG. 3B shows a state where the support substrate calcined body is evacuated. In FIG. 3 (b), the support substrate calcined body has a gas flow path penetrating in the length direction, and the air in the gas flow path is evacuated to both ends of the support substrate calcined body. Jigs 57 are mounted, and these jigs 57 are connected to a suction device 59.

Further, as shown in FIG. 3 (c), a plurality of gas passages are formed in the longitudinal direction of the support substrate calcined body ( width direction , linear between the arc-shaped portions B ), and finally immersed. The suction force of the gas passage formed on the side to be immersed is made larger than the suction force of the gas passage formed on the side immersed first, and the pressure of the gas passage formed on the side immersed last is by smaller than the pressure of the initially formed on the side which is immersed gas passage, you uniformly adjusting the thickness of the coating film of the solid electrolyte material is formed on the supporting substrate calcined body. In addition, although FIG. 3C illustrates an example in which the suction force in each gas passage is changed, for example, the suction force may be changed only in the upper and lower gas passages.

Thereafter, the coating film of the solid electrolyte layer formed on the fuel electrode layer calcined body of the support substrate calcined body is calcined at 800 to 1000 ° C. Thereafter, the interconnector material (e.g., LaCrO ₃ based oxide powder), an organic binder and a solvent were mixed to prepare a slurry, to produce the interconnector sheet. This interconnector sheet is further laminated at a predetermined position of the laminate obtained above to produce a firing laminate.

Next, the above-mentioned fired laminate is subjected to binder removal treatment, and co-fired at 1300 to 1600 ° C. in an oxygen-containing atmosphere, and an oxygen electrode forming material (for example, LaFeO ₃₎ is placed at a predetermined position of the obtained sintered body. A base oxide powder) and a paste containing a solvent, and, if necessary, a paste containing a P-type semiconductor layer forming material (for example, LaFeO ₃ oxide powder) and a solvent by a dip coating method or the like. By baking at 1300 degreeC, the fuel battery cell 30 of this invention of the structure shown in FIG. 1 can be manufactured.

  In the case where Ni alone is used to form the support substrate 31 and the fuel electrode layer 32, Ni is oxidized to NiO by firing in an oxygen-containing atmosphere. , Ni can be returned.

(Cell stack)
As shown in FIG. 2, the cell stack includes a plurality of the fuel cells 30 described above, and a metal felt and / or between one fuel cell 30 and the other fuel cell 30 adjacent in the vertical direction. A current collecting member 40 made of a metal plate is interposed, and both are connected in series with each other. That is, the support substrate 31 of one fuel battery cell 30 is electrically connected to the oxygen electrode 34 of the other fuel battery cell 30 via the interconnector 35, the P-type semiconductor layer 39, and the current collecting member 40. . Such cell stacks are arranged side by side as shown in FIG. 2, and adjacent cell stacks are connected in series by a conductive member 42.

Fuel cell, the cell stack of FIG. 2, and housed in a storage container. The storage container is provided with an introduction pipe for introducing a fuel gas such as hydrogen into the fuel battery cell 30 from the outside, and an introduction pipe for introducing an oxygen-containing gas such as air into the external space of the fuel battery cell 30. The fuel cell is heated to a predetermined temperature (for example, 600 to 900 ° C.) to generate electric power, and surplus fuel gas and oxygen-containing gas are burned and discharged out of the storage container.

  In addition, this invention is not limited to the said form, A various change is possible in the range which does not change the summary of invention. For example, the shape of the support 31 can be cylindrical.

  Further, in the above embodiment, the embodiment in which the coating film of the solid electrolyte material is formed on the fuel electrode layer calcined body by the dip coating method of the present invention has been described. Of course, a coating film may be formed by applying a fuel electrode material by a method.

  Furthermore, although the case where the support substrate is used has been described in the above embodiment, when the fuel electrode itself becomes a support, it is needless to say that a coating film of a solid electrolyte material may be formed on the fuel electrode.

NiO powder having an average particle size of 0.5 μm and Y ₂ O ₃ powder (average particle size is 0.6 to 0.9 μm), after firing, NiO is 48 vol% in terms of Ni, and Y ₂ O ₃ is 52 vol. %, And a clay prepared with an organic binder and a solvent was molded by extrusion molding, dried and degreased to produce a support substrate molded body. In addition, the shape immediately after extrusion molding of the support substrate molded body was 4.2 mm in thickness, 36 mm in width, and 270 mm in length in the axial length direction. Further, six through holes were provided at equal intervals in the flat portion of the support substrate molded body.

Next, a slurry for a fuel electrode layer is prepared by mixing an Ni powder having an average particle size of 0.5 μm, a ZrO ₂ powder in which a rare earth element is dissolved, an organic binder, and a solvent. It was applied and calcined at 1000 ° C.

Next, an immersion liquid is prepared by mixing ZrO ₂ powder in which 8 mol% of a rare earth element is dissolved, an organic binder, and a solvent. As shown in FIG. The support substrate calcined body 55 on which the calcined body was formed was immersed sideways to form a solid electrolyte coating film with a solid electrolyte thickness of 20 μm. Further, as shown in FIG. 3 (c), the suction force in each gas passage of the support substrate calcined body is the side where the suction force of the gas passage formed on the side immersed last is immersed first. A vacuum was drawn so as to gradually increase the suction force of the gas passage formed in this step (suction at 0.775 to 0.825 MPa) to form a solid electrolyte coating film. The degree of vacuum in the uppermost gas passage was 0.825 MPa, and the degree of vacuum in the lowermost gas passage was 0.775 MPa.

  As a comparative example, as shown in FIG. 4, the support substrate calcined body on which the fuel electrode calcined body is formed is immersed in the vertical direction to form a coating film of a solid electrolyte material, and a solid electrolyte molded body Formed.

  Next, the laminated molded body obtained by laminating the support substrate calcined body, the fuel electrode layer calcined body, and the solid electrolyte molded body was calcined at 1000 ° C.

Next, a slurry of a diffusion prevention layer prepared by adding an acrylic binder and toluene to a composite oxide (hereinafter referred to as SDC15) powder containing 85 mol% of CeO ₂ and 15 mol% of Sm ₂ O ₃ and mixing them, The obtained calcined body was coated on the surface of the solid electrolyte calcined body by a screen printing method.

Also, a slurry in which a LaCrO ₃ oxide, an organic binder and a solvent were mixed was prepared, and this was laminated on the exposed support substrate calcined body, and co-fired at 1485 ° C. firing temperature in an oxygen-containing atmosphere. .

The length in the longitudinal direction of the fired laminated sintered body was 19.2 cm, both ends of 2.375 cm were cut off with a diamond cutter, and the length in the axial length direction was 14.45 cm.

Next, a mixed liquid composed of La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ powder having an average particle diameter of 2 μm and isopropyl alcohol was prepared, and the surface of the diffusion preventing layer of the laminated sintered body was prepared. Spray coating was performed to form an oxygen electrode molded body, which was baked at 1150 ° C. to form an oxygen electrode, and a fuel battery cell as shown in FIG. 1 was produced.

  The size of the produced fuel cell is 2.5 cm × 14.45 cm, the thickness of the conductive support substrate is 3 mm, the open porosity is 35%, the thickness of the fuel electrode layer is 10 μm, the open porosity is 24%, The thickness of the oxygen electrode was 50 μm, the open porosity was 40%, the relative density of the solid electrolyte layer was 97%, and the thickness of the diffusion preventing layer was 5 μm.

  Next, hydrogen gas was allowed to flow inside the fuel cell, and the conductive support substrate and the fuel electrode were reduced at 850 ° C.

  A fuel gas was circulated through the fuel gas channel of the obtained fuel cell, an oxygen-containing gas was circulated outside the cell, and the fuel cell was heated to 850 ° C. using an electric furnace, and a power generation test was performed.

Further, when the thickness of the fuel cell was measured by observing a cross section of a portion of 7.225 cm from both ends in the longitudinal direction with an SEM, the thickness difference was 5 μm or less. Further, the cross section of a portion 1 cm (on the flat portion of the support substrate) from both ends in the longitudinal direction of the fuel cell was observed with an SEM, the film thickness was measured, and the measurement results are shown in Table 1.

From Table 1, when the immersion direction is the vertical direction, the film thickness difference of the solid electrolyte at both ends in the longitudinal direction is as large as 22 μm, but in the sample of the present invention in which the immersion direction is horizontal, the film thickness difference is 5 μm. It turns out that it is getting smaller. Furthermore, when evacuated, the film thickness difference is 1 μm, and the film thickness difference at the upper and lower ends can be substantially eliminated. It can also be seen that the power generation characteristics improve as the difference in film thickness of the solid electrolyte decreases.

The fuel cell of this invention is shown, (a) is a cross-sectional view, (b) is a perspective view. It is a cross-sectional view showing a cell stack formed by a plurality of fuel cells. It is explanatory drawing which shows the manufacturing process of the fuel battery cell of this invention. It is explanatory drawing which shows the manufacturing process of the conventional fuel cell. It is a cross-sectional view which shows the cell stack which consists of the conventional fuel cell.

Explanation of symbols

31 ... support substrate 31a ... fuel gas passage 32 ... fuel electrode layer 33 ... solid electrolyte layer 34 ... oxygen electrode 35 ... interconnector 40 ... current collecting member

Claims (3)

A method for producing a rod-shaped body having a coating film on the surface of a long porous body in which a plurality of gas passages are formed in the longitudinal direction inside ,
The porous body is immersed in the immersion liquid containing the coating film material from one side along the longitudinal direction, and the gas path immersed last is more than the gas path immersed first. A method for producing a rod-shaped body characterized by suction with a large suction force . A plurality of gas passages on longitudinally formed porous support therein, the inner porous electrode, a solid electrolyte, an outer porous electrode is provided a process for the preparation of rod-like fuel cells, which are sequentially formed, the porous The support is immersed in an immersion liquid containing the inner porous electrode material from one side along the longitudinal direction, and the last immersed gas passage is first immersed in the first gas passage. preparation of rod-shaped fuel cell which is characterized that you suction at greater attraction than. An inner porous electrode, a solid electrolyte, a method of manufacturing a rod-shaped fuel cell in which an outer porous electrode is sequentially formed, and the elongated inner porous electrode in which a plurality of gas passages are formed in a longitudinal direction inside , Alternatively, an elongate porous support having a plurality of gas passages formed in the longitudinal direction and having the inner porous electrode on the surface is immersed in a solid electrolyte material from one side along the longitudinal direction. A method for producing a rod-shaped fuel cell , wherein the gas passage is immersed in a liquid, and the gas passage that is immersed last is sucked with a larger suction force than the gas passage that is first immersed .

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