JP5111793B2 - Solid oxide fuel cell stack and manufacturing method thereof - Google Patents

Description

  The present invention relates to a horizontal stripe type solid oxide fuel cell stack and a manufacturing method thereof, and more particularly, in a horizontal stripe type solid oxide fuel cell stack, a horizontal stripe having an intermediate layer as an interconnector (IC) between cells. The present invention relates to a solid oxide fuel cell stack of the type and a manufacturing method thereof.

  A solid oxide fuel cell (hereinafter abbreviated as “SOFC” where appropriate) generally has a high operating temperature of about 800 to 1000 ° C., but recently it is about 800 ° C. or less, that is, 800 to 650 ° C. A range of operating temperatures is also being developed. The SOFC has an anode and a cathode arranged with an electrolyte material in between, and is composed of a three-layer unit of anode / electrolyte / cathode.

  During operation of the SOFC, electric power can be obtained by passing fuel to the anode side and passing an oxidant gas such as air to the cathode side and connecting both electrodes to an external load. However, since a single cell (also referred to as “cell” in this specification as appropriate) can only obtain a voltage of about 0.8 V at most, a plurality of single cells are connected in series to obtain practical power. There is a need to. Interconnectors and cells are stacked alternately for the purpose of properly distributing, supplying, and discharging fuel and air to and from the anode and cathode, respectively, at the same time that adjacent cells are electrically connected in series. The

  The SOFC as described above is a type in which a plurality of cells are stacked. However, instead of this, it is considered that the arrangement of the cells is a horizontal stripe method. The horizontal stripe method includes a cylindrical type (Japanese Patent Laid-Open No. 10-3932) and a hollow flat type (WO 2004/082058 A1, WO 2004/088783 A1).

JP-A-10-3932 WO 2004/082058 A1 WO 2004/088783 A1

  FIG. 17 is a diagram showing a configuration example of a hollow flat type disclosed in WO 2004/082058 A1. 17A is a perspective view, FIG. 17B is a plan view, and FIG. 17C is a cross-sectional view taken along line AA in FIG. 17B. In addition, description of the interconnector 16 is abbreviate | omitted in Fig.17 (a)-(b). A plurality of cells 15 each including an anode 12, an electrolyte 13 and a cathode 14 are sequentially formed on a hollow flat insulator substrate 11, and each cell is electrically connected in series via an interconnector 16. . As shown by arrows (→) in FIGS. 17A and 17C, the fuel flows through the space in the insulating substrate 11, that is, the fuel circulation portion 17 in parallel with the arrangement direction of the cells 15. Note that the number of fuel circulation portions is not limited to one and may be plural, and the cross-sectional shape thereof may be a polygonal shape (including a rectangular shape (including a hollow flat shape), a rectangular shape, etc.), a circular shape, an elliptical shape, and the like. Configured.

  FIG. 1 is a diagram for explaining the positional relationship of the interconnector 16, and shows two adjacent cell portions out of a plurality of cells arranged in a horizontal stripe shape as a cross-sectional view. In relation to the intermediate layer according to the present invention described below, the interconnector 16 shown in FIG. 17 is A, the supporting substrate is 1, the anode is 2, 2, the adjacent electrolyte is 3, 3, the adjacent cathode is 5, 5 As shown. The interconnector A electrically connects between adjacent cells, that is, between the anode of one cell and the cathode of a cell adjacent to the cell.

Examples of the constituent material of the interconnector A include the following materials (1) to (4). These materials are made into a slurry, for example, and the interconnector A is formed by film formation and drying.
(1) A material whose main component is an oxide represented by the formula (Ln, A) CrO ₃ (wherein Ln is a lanthanoid and A is Ba, Ca, Mg or Sr).
(2) An oxide containing Ti, such as MTiO ₃ (wherein M is at least one element selected from Ba, Ca, Pb, Bi, Cu, Sr, La, Li, and Ce).
(3) A material mainly composed of Ag. In the case of this material, it is desirable to cover the interconnector made of this material with glass.
(4) A material composed of one or more of Ag, Ag wax, and a mixture of Ag and glass.

  From the viewpoints of the relationship between the thermal expansion coefficients of electrolyte materials, anode materials, and cathode materials, and the cost, the present inventors paid particular attention to composite materials containing Ag and glass, among these interconnector materials. We are continuing experiments and developments toward the realization. In Japanese Patent Application No. 2005-005752 (filed on January 12, 2005, hereinafter referred to as “752 application”), there was a problem in durability when only a composite material containing Ag and glass was used. However, by forming an intermediate layer made of a composite material containing Ag and Ni (referred to as “Ag + Ni” where appropriate in this specification) between the anode and the interconnector material, the durability can be improved. It has improved.

Application for Japanese Patent Application No. 2005-005752

  Although the intermediate layer according to the 752 application is effective for improving durability, etc., the SOFC stack provided with this intermediate layer was further pursued in terms of its production process, performance after the start of power generation, etc. It was found that peeling is likely to occur, the yield and durability at the manufacturing stage are low, and after the start of power generation, the possibility of peeling and breakage is high due to the thermal cycle caused by repeated power generation and stoppage. The present invention has been made to solve these problems in a horizontal stripe SOFC stack having an intermediate layer.

  That is, the present invention further improves the problem of peeling, the yield at the production stage, and durability of the intermediate layer in the horizontal-striped solid oxide fuel cell stack, and prevents power generation and stoppage after the start of power generation. It is an object of the present invention to provide a horizontal stripe type solid oxide fuel cell stack and a method for producing the same, which solve the problem of peeling and breakage due to repeated thermal cycles.

  According to the present invention, (1) a plurality of cells including an anode, an electrolyte, and a cathode are sequentially formed on the surface of a support substrate having a fuel circulation portion therein, and adjacent cells are electrically connected via an interconnector. Is a solid oxide fuel cell stack of horizontal stripe type connected in series. Then, an intermediate layer having a large number of pores is arranged in a composite material made of Ag and Ni between the anode of the adjacent cell and the interconnector, and the composite material containing Ag and glass covers the upper surface and the electrolyte. It is characterized by comprising an interconnector consisting of

  According to the present invention, (2) a plurality of cells including an anode, an electrolyte, and a cathode are sequentially formed on the surface of a support substrate having a fuel circulation portion inside, and adjacent cells are electrically connected via an interconnector. Is a solid oxide fuel cell stack of horizontal stripe type connected in series. Then, between the anode of the adjacent cell and the interconnector, an intermediate layer having a large number of pores is arranged in a composite material mainly composed of Ag and Ni and containing glass, and the upper surface and the electrolyte are covered. An interconnector made of a composite material containing Ag and glass is provided.

In the present invention, (3) a plurality of cells composed of an anode, an electrolyte, and a cathode are sequentially formed on the surface of a support substrate having a fuel circulation portion therein, and adjacent cells are electrically connected via an interconnector. Is a solid oxide fuel cell stack of horizontal stripe type connected in series. An intermediate layer made of a composite material containing Ag and Ni as main components and containing glass is disposed between the anode and the interconnector of the adjacent cell, and the composite material containing Ag and glass covers the upper surface and the electrolyte. It is characterized by comprising an interconnector consisting of The present invention (3) is a reference invention.

According to the present invention, (4) a plurality of cells including an anode, an electrolyte, and a cathode are sequentially formed on the surface of a support substrate having a fuel flow portion therein, and adjacent cells are electrically connected via an interconnector. Is a solid oxide fuel cell stack of horizontal stripe type connected in series. An intermediate layer made of a composite material mainly composed of Ag and Ni and containing a non-reducible oxide is disposed between the anode and the interconnector of the adjacent cell, and the upper surface and the electrolyte are covered with Ag and glass. An interconnector made of a composite material containing The present invention (4) is a reference invention.

  According to the present invention, (5) a plurality of cells including an anode, an electrolyte, and a cathode are sequentially formed on the surface of a support substrate having a fuel flow portion therein, and between the anode and interconnector of adjacent cells, Horizontal stripe type solid oxide comprising an intermediate layer having a large number of pores in a composite material made of Ag and Ni, and an interconnector made of a composite material containing Ag and glass covering the upper surface and the electrolyte. This is a method for producing a fuel cell stack. Then, an intermediate layer having a large number of pores in the composite material made of Ag and Ni was added between the anode and the interconnector of the adjacent cells, and a pore forming agent was added to Ag and Ni as the main components. It is formed by applying a mixture and baking. The present invention (5) corresponds to the production method of the present invention (1).

  In the present invention, (6) a plurality of cells including an anode, an electrolyte, and a cathode are sequentially formed on the surface of a support substrate having a fuel circulation portion inside, and between the anode and interconnector of adjacent cells, An intermediate layer having a large number of pores is arranged in a composite material mainly composed of Ag and Ni and containing glass, and an interconnector made of the composite material containing Ag and glass is arranged so as to cover the upper surface and the electrolyte. This is a method for producing a horizontal oxide solid oxide fuel cell stack. An intermediate layer having a large number of pores in a composite material containing Ag and Ni as main components and containing glass is formed between Ag and Ni as main components between an anode and an interconnector of an adjacent cell. It is characterized by being formed by applying and baking a mixture to which a pore-forming agent and glass powder are added. The present invention (6) corresponds to the production method of the present invention (2).

  According to the present invention, in a solid oxide fuel cell stack of a horizontal stripe method having an intermediate layer as an inter-connector between cells, the yield and durability in the manufacturing stage are further improved, and the solid oxide of the horizontal stripe method is used. The thermal expansion during power generation of the physical fuel cell stack can be eased to solve the problem of separation and damage, and the problem of separation and damage due to the thermal cycle caused by repeated power generation and stoppage can be solved.

  In the horizontal stripe SOFC stack, the present invention provides “Ag” as a constituent material of an interconnector that electrically connects adjacent cells (that is, an anode of one cell and a cathode of the other cell). And a composite material comprising glass and an intermediate layer is placed between the anode of an adjacent cell and the “composite material comprising Ag and glass (ie, interconnector)”.

  The intermediate layer is a layer for improving the durability problem when a composite material containing Ag and glass is used as the constituent material of the interconnector. The mixing ratio of Ag and Ni in the composite material is the purpose of the improvement. However, it is preferable that the weight ratio is 7: 3 to 1: 9 as Ag: NiO.

  Further, in the relationship with the anode, the electrolyte, and the interconnector, the intermediate layer is disposed on the upper surface of the anode and between the electrolytes of adjacent cells, and the interconnector is disposed so as to cover the upper surface of the intermediate layer and the electrolyte. Although the intermediate layer is also an interconnector, the portion arranged on the upper surface of the anode and between the electrolytes of adjacent cells is referred to as an “intermediate layer” in this specification.

  In the present invention (1), when the intermediate layer is formed, a mixture containing “pore-forming agent” in Ag and Ni as main components is used. In the present invention (2), the intermediate layer is formed. In this case, a mixture containing “pore forming agent and glass powder” in Ag and Ni as main components is used, and in the present invention (3), “glass powder” is used as an intermediate layer in Ag and Ni as main components. In the present invention (4), a mixture containing “refractory oxide” in Ag and Ni as main components is used as the intermediate layer.

As a constituent material of the support substrate, a mixture of MgO and MgAl ₂ O ₄ , a zirconia-based oxide, a mixture of zirconia-based oxide, MgO and MgAl ₂ O ₄ , or the like is used, but is not limited thereto. Among them, a mixture of MgO and MgAl ₂ O ₄ is preferably a mixture of MgO contained 20～70Vol% of the total amount of MgO and MgAl ₂ O _4. Examples of zirconia-based oxides include yttria-stabilized zirconia [YSZ: (Y ₂ O ₃ ) _X (ZrO ₂ ) _1-X (where x = 0.03 to 0.12)]. It is done.

As a constituent material of the anode, for example, a material containing Ni as a main component, a ceramic material containing a metal, or the like is used, but the material is not limited to these materials. Among the ceramic materials containing metals, examples of the ceramic material include yttria-stabilized zirconia [YSZ: (Y ₂ O ₃ ) _X (ZrO ₂ ) _1-X (where x = 0.05 to 0.15)]. As the metal, at least one metal selected from Ni, Cu, Fe, Ru, and Pd, that is, one or more of these metals is used.

Among these metal-containing ceramic materials, Ni-containing YSZ (Ni—YSZ cermet), that is, Ni and [(Y ₂ O ₃ ) _X (ZrO ₂ ) _1-X (where x = 0.05-0. 15)] is a preferable anode material in the present invention, and it is particularly preferable that Ni in the mixture is dispersed in an amount of 40 vol% or more.

The constituent material of the electrolyte may be a solid electrolyte having ionic conductivity, and examples thereof include the following materials (1) to (4), but are not limited to these exemplified materials.
(1) Yttria-stabilized zirconia [YSZ: (Y ₂ O ₃ ) _X (ZrO ₂ ) _1-X (where x = 0.05 to 0.15)].
(2) Scandia-stabilized zirconia [(Sc ₂ O ₃ ) _X (ZrO ₂ ) _1-X (where x = 0.05 to 0.15)].
(3) Yttria-doped ceria [(Y ₂ O ₃ ) _X (CeO ₂ ) _1-X (where x = 0.02 to 0.4)].
(4) Gadria-doped ceria [(Gd ₂ O ₃ ) _X (CeO ₂ ) _1-X (where x = 0.02 to 0.4)].

  FIG. 2 is a diagram for explaining an example of the SOFC cell stack according to the present invention. Among a plurality of cells arranged in a horizontal stripe, two adjacent cells are taken out and shown as a cross-sectional view. In FIG. 2A, 1 is a support substrate, 2 is an anode, 3 is an adjacent electrolyte, and A is an interconnector. As shown in FIG. 2A, in the present invention, an intermediate layer B is provided between the anode of an adjacent cell and the interconnector A.

  In the present invention (1), when the intermediate layer B is formed, a mixture containing “pore forming agent” in Ag and Ni as main components is used. In the present invention (2), the intermediate layer B is used. In the present invention (3), a mixture containing “pore-forming agent and glass powder” in Ag and Ni as main components is used, and in the present invention (3), “Glass” is added to Ag and Ni as main components. In the present invention (4), a composite material containing “refractory oxide” in Ag and Ni as main components is used as the intermediate layer.

<Mode of Intermediate Layer B in the Present Invention (1)>
In the present invention (1), when forming the intermediate layer B, a “pore-forming agent” is added to Ag and Ni as the main components. The pore-forming agent is a material for forming a large number of pores in the intermediate layer B. As the pore-forming agent, carbon powder, fibrous carbon powder, liquid or solid hydrocarbon, or the like is used. The amount of pore-forming agent added is desirably 1 wt% or more and 20 wt% or less with respect to “Ag + NiO”.

When forming the intermediate layer B, a pore forming agent is mixed with Ag and Ni as the main components, applied, and then fired to burn off the pore forming agent to form a large number of holes. The intermediate layer B formed in this way is composed of Ag and Ni as main components except for the holes. The composite material constituting the intermediate layer B may contain ZrO ₂ and other trace components. The same applies to the intermediate layer B in the present invention (2) to (4) described below.

<Aspect of the intermediate layer B in the present invention (2)>
In the present invention (2), when forming the intermediate layer B, a pore former and glass powder are added to Ag and Ni as the main components. The pore-forming agent is a material that forms a large number of pores in the intermediate layer B. As the pore-forming agent, carbon powder, fibrous carbon powder, liquid or solid hydrocarbon, or the like is used. Glass powder, to reduce thermal expansion coefficient of the intermediate layer B, as long as it serves to increase the bonding _{strength, SiO 2 · B 2 O 3} · MgO · CaO · BaO based bonding material as an example, SiO Examples thereof include ₂ · SrO · K ₂ O · Na ₂ O-based bonding materials. As for glass powder and a pore making material, it is desirable that the addition amount of both components is 1 wt% or more and 20 wt% or less with respect to “Ag + NiO”.

  At the time of forming the intermediate layer B, a pore forming agent and glass powder are mixed and applied to Ag and Ni as the main components, applied, and then fired to burn off the pore forming agent to form a large number of holes. Of the intermediate layer B formed in this way, the portions other than the numerous holes are made of Ag, Ni, and glass.

  FIG. 3 is a diagram for explaining an intermediate layer B formed by adding a pore forming agent or a pore forming agent and glass powder to Ag and Ni as main components. As shown in FIG. 3A, a large number of holes are formed by the pore-forming agent flying by firing when the intermediate layer B is formed. Thereby, the thermal expansion at the time of operation of the SOFC stack can be relaxed, and the problem of peeling and breakage can be solved. FIG. 3B is an enlarged view of a part of the intermediate layer B in FIG.

<Aspect of the intermediate layer B in the present invention (3)>
In the present invention (3), when the intermediate layer B is formed, a composite material in which glass is added to Ag and Ni as main components is applied and then dried. And after applying <the constituent material of the interconnector A> mentioned later, it co-fires. The glass powder only needs to play a role of relaxing the thermal expansion of the intermediate layer B and increasing the bonding strength. Examples thereof include SiO ₂ · B ₂ O ₃ · MgO · CaO · BaO based bonding material, SiO ₂ etc. _{· SrO · K 2 O · Na} 2 O -based bonding material and the like. The amount of glass powder added is desirably 1 wt% or more and 20 wt% or less with respect to “Ag + NiO”.

  FIG. 4 is a diagram for explaining an intermediate layer B formed by adding glass powder to Ag and Ni as main components. As shown in FIG. 4, the intermediate layer B is composed of Ag and Ni as main components and glass. Among these, the glass component improves the adhesion with the anode 2 as compared with the case of Ag and Ni alone. be able to. As a result, the yield and durability in the manufacturing stage can be further improved, and thermal expansion during power generation of the SOFC stack can be mitigated to solve the problem of peeling and breakage.

<Mode of Intermediate Layer B in the Present Invention (4)>
In the present invention (4), at the time of forming the intermediate layer B, a composite material containing a hardly-reducible oxide is applied to Ag and Ni as the main components and dried. Then, a <constituent material for interconnector A> described later is applied and co-fired. The non-reducible oxide may be any oxide that has a role of relaxing the thermal expansion of the intermediate layer B mainly composed of Ag and Ni and increasing the bonding strength, and examples thereof include Y ₂ O ₃ . Here, “non-reduced” in the non-reduced oxide means that it is stable at 300 to 900 ° C. in a hydrogen atmosphere or a mixed atmosphere of hydrogen and water vapor. Things are included. The addition amount of the hardly-reducible oxide is preferably 1 wt% or more and 20 wt% or less with respect to “Ag + NiO”. The intermediate layer B in this case is also as shown in FIG.

<Components of interconnector A>
Next, as a constituent material of the interconnector A, a composite material containing Ag and glass is used. In this composite material, Ag, which is an electrically conductive material, is mixed in order to pass a current through glass, which is an insulator, and the mixture is used as a constituent material of the interconnector A. As the Ag component, in addition to Ag itself, for example, an alloy containing Ag such as an Ag—Pd alloy or a metal brazing material containing Ag can be used. In the present specification and claims, “Ag” in the “composite material containing Ag and glass” means to include an alloy containing these Ag and a metal brazing material containing Ag.

There is no particular limitation on the type of glass of the composite material constituting the interconnector A. The glass contains K ₂ O, ZnO, BaO, Na ₂ O, CaO, etc. in a network structure containing SiO ₂ or Al ₂ O ₃ in addition thereto, such as soda glass, borosilicate glass, quartz Glass or other suitable materials can be selected and used. As its characteristics, it is desirable that the glass has a thermal expansion coefficient in the range of 6.0 to 14.0 × 10 ⁻⁶ and that the softening point is in the range of 600 ° C. to 1000 ° C.

The composite material constituting the interconnector A may contain ZrO ₂ and other trace components. Regarding the composite material constituting the interconnector A, in the present specification and claims, “composite material containing Ag and glass” is meant to include a mixture of Ag and glass, as well as a case where a trace component is contained therein. is there. As described above, the interconnector A is composed of “a composite material containing Ag and glass”, and a corresponding mixture of Ag powder and glass powder is used when the interconnector A is formed.

  Ag powder is usually mixed with glass powder in the form of spherical or granular, but using flaky Ag powder as Ag powder can greatly improve the voltage loss in SOFC stack. In addition, an interconnector with little voltage loss between cells can be formed with good reproducibility. As described above, the technique of using flaky Ag powder as the Ag component of the interconnector A was previously developed by the present inventors [Japanese Patent Application No. 2006-0669457 (application date = March 14, 2006). This technique can also be applied in the present invention.

Application for Japanese Patent Application No. 2006-0669457

  The intermediate layer B is also an interconnector, and the adjacent cells are electrically connected by an interconnector including the interconnector B and the interconnector A, which are the intermediate layer B. FIG. 2B shows a current flow when the SOFC stack is operated.

  FIG. 5 is a diagram for explaining the formation process of one embodiment of the SOFC stack having the intermediate layer B according to the present invention. In FIG. 5, the same members and portions as those shown in FIGS. As shown in FIG. 5A, the anodes 2 and 2 are formed and arranged on the upper surface of the support substrate 1. This stage is shown in FIG. Next, as shown in FIG. 5C, the electrolytes 3 and 3 are arranged, and the recesses 4 are formed between the electrolytes 3 and 3. Next, the cathode 5 is disposed on the surfaces of the electrolytes 3 and 3. This stage is shown as FIG.

  In the present invention (1), the intermediate layer B is formed by applying and firing a composite material containing Ag and Ni as main components and including a pore-forming agent in the recess 4. In the present invention (2), the recess 4 is formed in the recess 4. The intermediate layer B is formed by applying and baking a composite material containing Ag and Ni as main components and containing a pore-forming agent and glass powder. FIG. 5 (e) shows this stage. Then, as shown in FIG.5 (f), the composite material containing Ag and glass powder is distribute | arranged, and the interconnector A is formed.

  Moreover, in this invention (3), after apply | coating and drying the composite material which has Ag and Ni as a main component and containing glass powder to the recessed part 4, this invention (4) WHEREIN: Ag and Ni are made into the recessed part 4. After the composite material containing the main component and the non-reducible oxide is applied and dried, the composite material containing Ag and glass powder is applied and co-fired as shown in FIG. B and interconnector A are formed.

  In any of the present inventions (1) to (4), the interconnector B which is the intermediate layer B is located on the upper surface of the anode 2 of the adjacent cell and the electrolyte 3 of the adjacent cell in the positional relationship with respect to the anode and the electrolyte. 3 is provided.

  The present invention is applied to a horizontal stripe type SOFC in which a support substrate having a fuel circulation portion therein has a circular cross section, an elliptical cross section, a polygonal cross section, or the like. The cross-sectional polygonal shape includes a rectangular cross-sectional shape (including a hollow flat shape), a rectangular cross-sectional shape, a pentagonal cross-sectional shape, and various other shapes. The one shown in FIG. It is flat.

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, it cannot be overemphasized that this invention is not limited to an Example.

  Various types of simulated SOFC cells having an intermediate layer were prepared, and performance tests were performed on these SOFC simulated cells in order to confirm the effect. 6 to 8 are diagrams showing these simulated SOFC cells. FIG. 6 shows a cell composed of a material made of Ag + Ni as the intermediate layer B (hereinafter referred to as “comparative SOFC simulation cell”), and FIG. 7 shows an intermediate layer B made of Ag + Ni using Avicel as a pore forming agent. FIG. 8 shows a cell formed by adding glass powder to Ag + Ni as the intermediate layer B (hereinafter referred to as “SOFC simulated cell of Example 2”). It is.

<Production of Comparative Example SOFC Simulated Cell>
A cell composed of an interconnector having an intermediate layer B was produced as follows. An anode layer made of Ni-YSZ cermet was disposed. It is a layer shown as 2 in FIG. On the surface of the anode layer, a space was provided at the center, and an electrolyte composed of YSZ was disposed on both the left and right sides. It is a member shown as 3, 3 in FIG. A concave portion corresponding to the distance between the central portions is formed between the electrolytes 3 and 3 on both the left and right sides.

  Subsequently, the paste of the mixture of Ag and NiO was apply | coated to the said recessed part, and it dried and the intermediate | middle layer B was formed. The mixture of Ag and NiO is a paste obtained by mixing Ag powder and NiO powder in an organic solvent (mixed solvent of toluene and 2-propanol) at a weight ratio of 6: 4 and mixing by a ball mill for 20 hours. is there.

Thereafter, a paste of a mixture of Ag powder and glass powder was applied to the upper surface of the interconnector B as an intermediate layer and the electrolytes 3 and 3 on both the left and right sides, and dried to form an interconnector A. This mixture of Ag powder and glass powder is composed of an organic solvent (mixed solvent of toluene and 2-propanol) and Ag powder and glass powder (SiO ₂ —SrO—K ₂ O—Na ₂ O-based bonding material) in a weight ratio of 7: 3 was mixed at a ratio of 3 and mixed for 20 hours by a ball mill.

<Production of SOFC Simulated Cell of Example 1>
A cell composed of an interconnector having an intermediate layer B having a large number of holes therein was produced as follows. An anode layer made of Ni-YSZ cermet was disposed. It is a layer shown as 2 in FIG. On the surface of the anode layer, a space was provided at the center, and an electrolyte composed of YSZ was disposed on both the left and right sides. It is a member shown as 3, 3 in FIG. A concave portion corresponding to the distance between the central portions is formed between the electrolytes 3 and 3 on both the left and right sides.

  Next, after applying a paste of a mixture in which Ag and NiO are main components in the concave portion and carbon powder (Avicel) is added thereto, the intermediate layer B is formed by heating and baking at 900 ° C. The mixture of Ag, NiO, and carbon powder was prepared by mixing Ag powder, NiO powder, and carbon powder in an organic solvent (mixed solvent of toluene and 2-propanol) at a weight ratio of 5.4: 3.6: 1. It is made into a paste by mixing for 20 hours in a ball mill.

Thereafter, a paste of a mixture of Ag powder and glass powder was applied to the upper surface of the interconnector B as an intermediate layer and the electrolytes 3 and 3 on both the left and right sides, and dried to form an interconnector A. This mixture of Ag powder and glass powder is composed of an organic solvent (mixed solvent of toluene and 2-propanol) and Ag powder and glass powder (SiO ₂ —SrO—K ₂ O—Na ₂ O-based bonding material) in a weight ratio of 7: 3 was mixed at a ratio of 3 and mixed for 20 hours by a ball mill.

<Production of SOFC Simulated Cell of Example 2>
A cell composed of an interconnector having an intermediate layer B was produced as follows. An anode layer made of Ni-YSZ cermet was disposed. It is a layer shown as 2 in FIG. On the surface of the anode layer, a space was provided at the center, and an electrolyte composed of YSZ was disposed on both the left and right sides. It is a member shown as 3, 3 in FIG. A concave portion corresponding to the distance between the central portions is formed between the electrolytes 3 and 3 on both the left and right sides.

Subsequently, after applying the paste of the mixture which made Ag and NiO the main components in this recessed part and added glass powder to this, it dried at 130 degreeC. This part becomes an intermediate layer by the next co-firing. As the glass powder, a SiO ₂ · B ₂ O ₃ · MgO · CaO · BaO based bonding material was used. The mixture of Ag, NiO and glass powder is prepared by mixing Ag powder, NiO powder and glass powder in an organic solvent (mixed solvent of toluene and 2-propanol) at a weight ratio of 5.4: 3.6: 1. It is made into a paste by mixing for 20 hours in a ball mill.

Thereafter, a paste of a mixture of Ag powder and glass powder was applied to the paste portion and the upper surfaces of the electrolytes 3 and 3 on both the left and right sides, and then heated to 900 ° C. and co-fired. As a result, the mixture layer in which glass powder is added to the main components Ag and NiO becomes the intermediate layer B, the mixture layer of Ag powder and glass powder becomes the interconnector A, and the cell composed of the interconnector having the intermediate layer B is formed. Produced.
The mixture of the Ag powder and the glass powder is composed of an organic solvent (a mixed solvent of toluene and 2-propanol) and an Ag powder and a glass powder (SiO ₂ —SrO—K ₂ O—Na ₂ O-based bonding material) in a weight ratio of 7: 3 was mixed at a ratio of 3 and mixed for 20 hours by a ball mill.

<Production of SOFC Simulated Cell of Example 3>
Intermediate layer B was prepared in the same manner as in <Preparation of SOFC simulated cell of Example 2> except that Y ₂ O ₃ powder was used instead of the glass powder in the intermediate layer B in <Preparation of SOFC simulated cell of Example 2>. And the interconnector A was formed, and a cell constituted by the interconnector having the intermediate layer B was produced.

<performance test>
The voltage loss was measured for each of the SOFC simulated cells produced as described above. FIG. 9 is a diagram illustrating a process in which each SOFC simulated cell is processed for use in measurement. As shown in FIG. 9C, the current collector 6 is disposed so as to cover the upper surface of the interconnector A in the SOFC simulated cell. Further, as shown in FIGS. 9A to 9C, a circular metal foil 7 is disposed on the peripheral upper surfaces of the electrolytes 3 and 3 in order to prevent mixing of hydrogen and air (oxygen) in the vicinity of the SOFC simulation cell.

  Each SOFC simulated cell thus processed was set in an electric furnace, and the presence / absence and degree of voltage loss were measured for each. FIG. 10 shows an outline of the test apparatus. 8 is an electric furnace heater, 9 is an electric furnace outer peripheral wall, and an SOFC simulation cell is arranged at the center thereof. Then, as shown, a current generator and a voltage measuring device are set between the current collector 6 and the anode 2 of the SOFC simulation cell.

  The current generator is for flowing current from the outside. This test device is a device for measuring the presence / absence and degree of voltage loss in the interconnector, and is a mechanism for measuring the voltage loss when a current is passed.

In this performance test, hydrogen was supplied to the anode side, air was supplied to the interconnector side, the operating temperature was 700 ° C., and the current density was constant at 0.9 A / cm ² . 11 to 12 are diagrams showing the results. 11 to 12, the horizontal axis represents time (h), and the vertical axis represents voltage loss (mV). The higher this voltage, the worse the performance when made into a cell.

<Test results of SOFC simulation cell of comparative example>
FIG. 11 shows measured values for the SOFC simulation cell of the comparative example. As shown in FIG. 11, the loss voltage increases rapidly with the passage of time, showing a value of 33 mV (= 0.033 V) when 50 hours have passed and 53 mV when 70 hours have passed, which is a considerable voltage loss.

<Test Results of SOFC Simulated Cell of Example 1>
FIG. 12 shows measured values for the SOFC simulated cells of Examples 1 to 3, and also shows the data of the SOFC simulated cell of the comparative example of FIG. As shown in FIG. 12, the loss voltage of the SOFC simulated cell of Example 1 is about 0.3 mV from the beginning of the measurement, which is orders of magnitude smaller than the loss voltage of the SOFC simulated cell of the comparative example. Further, the loss voltage of the SOFC simulated cell of Example 1 slightly fluctuates in the middle, but hardly changes even after 280 hours.

<Test Results of SOFC Simulated Cell of Example 2>
As shown in FIG. 12, the loss voltage for the SOFC simulated cell of Example 2 is about 0.5 mV from the beginning of the measurement, and slightly increases and decreases in the middle, but hardly changes even when 285 hours elapse. The size of the SOFC simulation cell of Example 1 is somewhat larger than the loss voltage of the SOFC simulation cell of the comparative example.

<Test Results of SOFC Simulated Cell of Example 3>
As shown in FIG. 12, the loss voltage for the SOFC simulated cell of Example 3 is 38.0 mV at the start of measurement, but then suddenly decreases, decreases to 19.50 mV after 25 hours, and increases slightly thereafter. However, it is about 25 mV even after 300 hours. It is an order of magnitude smaller than the loss voltage of the SOFC simulation cell of the comparative example.

  FIGS. 13 to 16 are cross-sectional micrographs after <performance test> for the comparative example SOFC simulated cell, the SOFC simulated cell of Example 1, the SOFC simulated cell of Example 2, and the SOFC simulated cell of Example 3. FIG. First, as shown in FIG. 13, in the SOFC simulation cell of the comparative example, the anode 2 (upper surface) and the intermediate layer B (lower surface) are separated as shown by “Z” in FIG. It was observed.

  As shown in FIG. 14, in the SOFC simulation cell of Example 1, there was no separation between the anode 2 and the intermediate layer B, and the anode 2 and the intermediate layer B were in close contact, and a large number of pores were observed in the intermediate layer B. Further, as shown in FIG. 15, in the SOFC simulated cell of Example 2, it was observed that the anode 2 and the intermediate layer B were not spaced apart and closely adhered. FIG. 16, which is a cross-sectional micrograph after the <performance test> of the SOFC simulated cell of Example 3, was also substantially the same as in FIG. 15.

The figure explaining the arrangement | positioning relationship of the interconnector 16 among the structural examples of the hollow flat type SOFC cell stack shown in FIG. The figure explaining the example of an aspect of the SOFC cell stack concerning this invention The figure explaining the intermediate | middle layer B formed by adding a pore making material or a pore making agent, and glass powder with respect to Ag and Ni which are main components. The figure explaining the intermediate | middle layer B formed by adding glass powder with respect to Ag and Ni which are main components. The figure explaining the formation process of the SOFC stack which has the intermediate | middle layer B which concerns on this invention Diagram showing a comparative example SOFC simulation cell The figure which shows the SOFC simulation cell of Example 1. The figure which shows the SOFC simulation cell of Example 2. The figure explaining the process which processed each SOFC simulation cell in order to use for measurement The figure which shows the outline of the test equipment which measured voltage loss as a performance test The figure which shows the measurement result of the voltage loss of the SOFC simulation cell of the comparative example 1 The figure which shows the measurement result of the voltage loss of the SOFC simulation cell of Examples 1-3. Drawing of micrograph after <performance test> of SOFC simulation cell of comparative example The figure which made the micrograph after <performance test> of the SOFC simulation cell of Example 1 into a drawing The figure which made the micrograph after the <performance test> of the SOFC simulation cell of Example 2 into a drawing The figure which made the micrograph after the <performance test> of the SOFC simulation cell of Example 3 into a drawing Diagram showing a configuration example of a hollow flat type horizontal stripe SOFC

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support substrate 2 Anode 3 Electrolyte 4 Recessed part (becomes an intermediate layer)
5 Cathode A Interconnector B Intermediate layer (interconnector)
6 Current Collector 7 Metal Foil 8 Electric Furnace Heater 9 Electric Furnace Outer Wall 11 Hollow Flat Insulator Substrate 12 Anode 13 Electrolyte 14 Cathode 15 Cell 16 Interconnector 17 Fuel Distribution Portion

Claims (6)

A plurality of cells composed of an anode, an electrolyte, and a cathode are sequentially formed on the surface of a support substrate having a fuel circulation portion therein, and adjacent cells are electrically connected in series via an interconnector. A horizontal oxide solid oxide fuel cell stack,
An intermediate layer having a large number of pores is arranged in a composite material made of Ag and Ni between the anode and the interconnector of an adjacent cell, and the upper surface and the electrolyte are covered, and the composite material contains Ag and glass. A solid oxide fuel cell stack of a horizontal stripe system characterized by comprising an interconnector. A plurality of cells composed of an anode, an electrolyte, and a cathode are sequentially formed on the surface of a support substrate having a fuel circulation portion therein, and adjacent cells are electrically connected in series via an interconnector. A horizontal oxide solid oxide fuel cell stack,
Between the anode of the adjacent cell and the interconnector, an intermediate layer having a large number of pores is arranged in a composite material mainly composed of Ag and Ni and containing glass, and the upper surface and the electrolyte are covered with Ag. A solid oxide fuel cell stack of a horizontal stripe type characterized by arranging an interconnector made of a composite material containing glass. 3. The solid oxide fuel cell stack according to claim 1, wherein the interconnector is formed using a mixture containing glass powder and flaky Ag powder. Battery stack. A composite cell composed of Ag and Ni 2 O is formed between the anode and the interconnector of the adjacent cells by sequentially forming a plurality of cells composed of an anode, an electrolyte, and a cathode on the surface of the support substrate having a fuel circulation portion inside. A horizontal-stripe solid oxide fuel cell stack is produced, in which an intermediate layer having a large number of pores is arranged in the material, and an interconnector made of a composite material containing Ag and glass is arranged on the upper surface and the electrolyte. A way to
In the composite material composed of Ag and Ni 2 O , a pore-forming agent was added to Ag and Ni 2 O , which are the main components, between the anode and interconnector of the adjacent cell. A method for producing a horizontal oxide solid oxide fuel cell stack, which is formed by applying a mixture and firing. The surface of the support substrate having the internal fuel flow part provided therein, sequentially, the main component anode, to form a plurality of cells consisting of an electrolyte and a cathode, between the anode and the interconnector adjacent cells, the Ag and Ni O In addition, an intermediate layer having a large number of pores is disposed in a composite material containing glass, and an interconnector made of a composite material containing Ag and glass is arranged on the upper surface and the electrolyte to form a horizontal stripe type solid oxide A method of manufacturing a physical fuel cell stack, comprising:
An intermediate layer having a large number of pores in a composite material containing Ag and Ni 2 O as main components and glass is formed between Ag and Ni 2 O , which are the main components, between an anode and an interconnector of an adjacent cell. A method for producing a horizontal stripe type solid oxide fuel cell stack, which is formed by applying a mixture containing a pore former and glass powder and firing the mixture. 6. The method for producing a solid oxide fuel cell stack according to claim 4, wherein the pore former is carbon powder or fibrous carbon powder. .

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