JP2009199956A - Horizontal stripe type solid oxide fuel cell stack and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein lanthanum chromite is used as an inter-connector material in a horizontal stripe type solid oxide fuel cell tack. <P>SOLUTION: In the horizontal stripe type solid oxide fuel cell tack and its manufacturing method, a plurality of cells made of an anode layer, an electrolyte layer, and a cathode layer are formed on the surface of a porous support substrate having a fuel passage in the inside, and adjacent cells are electrically connected in series via an inter-connector made of lanthanum chromite or a material of lanthanum chromite as a major component. A section of the anode layer where the inter-connector is arranged is set up to be an anode layer excluding zirconia, and a section involved on cell reaction is set up to be a section where the inter-connector is arranged, an anode layer with composition excluding common zirconia, and an anode layer with composition including zirconia, which is laminated on the above anode layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a horizontal stripe solid oxide fuel cell stack and a method for manufacturing the same.

  A solid oxide fuel cell includes a three-layer unit in which an anode layer and a cathode layer are arranged with an electrolyte layer made of a solid oxide interposed therebetween. The operating temperature is generally as high as about 800 to 1000 ° C., but an operating temperature of about 800 to 650 ° C. is being developed.

  During operation of the solid oxide fuel cell, electric power can be obtained by passing fuel to the anode layer side and passing an oxidant gas such as air to the cathode layer side and connecting both electrodes to an external load. However, since a single cell (hereinafter referred to as “cell”) can only obtain a voltage of about 0.8 V at most, it is necessary to electrically connect a plurality of cells in series in order to obtain practical power. There is. 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 layers at the same time that adjacent cells are electrically connected in series. Is done.

  The solid oxide fuel cell as described above is a type in which a plurality of cells are stacked, but a solid oxide fuel cell of a type in which a plurality of cells are arranged in a horizontal stripe shape is also considered. The horizontal stripe method includes a cylindrical type (Japanese Patent Laid-Open No. 10-3932) and a hollow flat type (International Publication No. 2004/082058, International Publication No. 2004/088783).

JP-A-10-3932 International Publication No. 2004/082058 Pamphlet International Publication No. 2004/088783 Pamphlet

  FIG. 1 is a diagram showing a configuration example of a hollow flat type horizontal stripe type solid oxide fuel cell. 1A is a perspective view, FIG. 1B is a plan view, and FIG. 1C is a cross-sectional view taken along line XX in FIG. 1B. A plurality of cells 5 formed by laminating an anode layer 2, an electrolyte layer 3, and a cathode layer 4 are sequentially formed on a hollow flat, porous, electrically insulating support substrate 1. The adjacent cells 5 are electrically connected in series via the interconnector 6 and the current collector 7. The support substrate 1 is also called a support base, an insulating substrate, a tube substrate, a flat tube substrate, or the like, but it is essential that the support substrate 1 has a large number of pores through which fuel gas passes, that is, is porous.

  The fuel gas is circulated in the space in the porous support substrate 1, that is, the fuel flow path 8 in parallel with the arrangement of the cells 5. The number of fuel flow paths 8 is not limited to one, and a plurality of fuel flow paths 8 may be used, and the cross-sectional shape of the fuel flow paths 8 may be a rectangular shape (including hollow flat shape), a rectangular shape, an elliptical shape, or the like.

  Here, according to FIG. 2, an example of a manufacturing process of the horizontal stripe type solid oxide fuel cell stack will be described. FIG. 2A shows a porous support substrate 1, and an anode layer 2 is disposed on the porous support substrate 1 as shown in FIG. Next, the interconnector 6 is disposed as shown in FIG. 2C, and the electrolyte layer 3 is disposed as shown in FIG. And the cathode layer 4 is arrange | positioned as FIG.2 (e), and the electrical power collector 7 is arrange | positioned as FIG.2 (f).

  The porous support substrate 1 has a fuel flow path 8 inside, and is configured such that at least a surface in contact with the cell 5 is electrically insulating. In the example of FIG. 2, the lower surface side of the porous support substrate 1 becomes the fuel flow path 8 [see FIG. 1 (c)], and the upper surface side is configured to be electrically insulating. That is, since the anode layer 2 and the electrolyte layer 3 are in contact with the upper surface side of the porous support substrate 1, the surfaces of the upper and lower surfaces of the porous support substrate 1 that are in contact with the anode layer 2 and the electrolyte layer 3 are electrically insulating. To do.

  The current collector 7 is electrically connected with the interconnector 6 between the anode layer 2 and the cathode layer 4 of the adjacent cell 5, that is, between the anode layer 2 of one cell 5 and the cathode layer 4 of the cell adjacent to the cell 5. In this specification, the current collector is referred to as a current collector because it is a kind of interconnector.

  In producing such a horizontal stripe type solid oxide fuel cell stack, first, in producing the porous support substrate 1, the raw material powder is mixed, granulated, and formed into the fuel flow path 8 by extrusion molding or the like. A green substrate having an opening (space) is produced. For example, graphite is added to the raw material powder as an auxiliary material for facilitating molding and making it porous during sintering. Next, an anode layer material is applied onto the green substrate by screen printing or the like, and both are sintered together. A material containing Ni is used as the constituent material of the anode layer 2, and as a preferred example, a mixture of Ni and yttria-stabilized zirconia is used.

  Next, after the interconnector material is applied to the interconnector disposition portion on the upper surface of the anode layer 2 as shown in FIG. 2C, the electrolyte layer material is applied and sintered as shown in FIG. As a constituent material of the electrolyte layer 3, yttria stabilized zirconia or the like is used.

  Next, the cathode layer material is applied to the upper surface of the electrolyte layer 3 as shown in FIG. 2D, and the current collector material is applied as shown in FIG. When these materials are applied, they are applied as a slurry or paste with water or an organic solvent. Further, since the plurality of cells 5 are arranged at intervals in the horizontal stripe type, the coating process after the application of the anode layer material is appropriately performed using a mask or the like.

  In the horizontal stripe type solid oxide fuel cell, since the fuel gas diffuses in the support substrate, the support substrate must have a porous structure. Further, in order to prevent the fuel gas from flowing out, it must be well isolated from the oxidizing atmosphere outside the porous support substrate through a dense member. And the electrolyte layer and interconnector which are the members which prevent the outflow of such fuel gas require baking at high temperature. Further, the interconnector formed on the anode layer is in contact with the electrolyte layer, and when yttria-stabilized zirconia is used as a constituent material of the electrolyte layer, the interconnector is in contact with the constituent zirconia.

  In addition, lanthanum chromite is useful as a constituent material of the interconnector in consideration of use at a higher temperature, but high-temperature firing is required to sinter lanthanum chromite densely. However, the firing temperature when forming a dense lanthanum chromite thin film has an upper limit of 1550 ° C., for example, as described in JP-A-9-263961, and firing shrinkage occurs significantly at 1550 ° C. or higher. , Causing burnout and the like, and a stable film cannot be obtained. In addition, the support substrate needs to have holes for the fuel gas to diffuse, and there is a limit of an upper limit temperature of about 1500 ° C. as a firing temperature requirement in order to ensure the porosity.

JP-A-9-263916

  By the way, the present inventors use a mixture of Ni and yttria stabilized zirconia as the constituent material of the anode layer, use yttria stabilized zirconia as the constituent material of the electrolyte layer, and use lanthanum chromite as the material of the interconnector. In consideration of the above-mentioned facts related to firing shrinkage, turning, etc., sintering was performed at 1500 ° C., and the denseness at the joint between the lanthanum chromite, which is the constituent material of the interconnector, and zirconia, which is the constituent material of the anode layer, was reduced. I found out. When the denseness is lowered, the outflow of the fuel gas cannot be prevented and is not isolated from the oxidizing atmosphere outside the substrate.

  In the present invention, by solving the problem of such a decrease in density, the production yield is improved, and fuel gas leakage, reduction in power generation efficiency, and further destruction and deterioration due to temperature increase due to combustion, etc. This is a solution to this problem.

  That is, the present invention provides a horizontally-striped solid oxide fuel cell stack that solves the above-mentioned problems when using lanthanum chromite or a material mainly composed of lanthanum chromite as a constituent material of its interconnector. It is an object of the present invention to provide an oxide fuel cell stack and a method for manufacturing the same.

  In the present invention (1), a plurality of cells comprising an anode layer, an electrolyte layer, and a cathode layer are arranged at intervals on the surface of a porous support substrate having a fuel flow path therein, and between adjacent cells. Is a horizontally-striped solid oxide fuel cell stack electrically connected in series via an interconnector made of lanthanum chromite or a material mainly composed of lanthanum chromite, wherein (a) The portion where the interconnector is disposed is an anode layer (first anode layer) having a composition not containing zirconia, and (b) the portion related to the battery reaction is made of zirconia common to the portion where the interconnector is disposed. An anode layer (first anode layer) having a composition not containing an anode layer (second anode layer) having a composition containing zirconia laminated thereon It is a segmented-in-series solid oxide fuel cell stack, characterized in comprising.

  In the present invention (2), a plurality of cells comprising an anode layer, an electrolyte layer, and a cathode layer are formed at intervals on the surface of a porous support substrate having a fuel flow path therein, and between adjacent cells. Are connected in series via an interconnector made of lanthanum chromite or a material containing lanthanum chromite as a main component to produce a horizontal stripe-type solid oxide fuel cell stack. ) A lanthanum chromite or material containing lanthanum chromite as a main component at the time of completion as a horizontally-striped solid oxide fuel cell stack is disposed in the anode layer (first zirconia-free composition) (B) a cell reaction at the time of completion as a horizontally-striped solid oxide fuel cell stack In the part concerned, an anode layer (second anode layer) containing zirconia is formed on the anode layer (first anode layer) containing no zirconia in common with the part where the interconnector is disposed. This is a method for manufacturing a horizontal stripe type solid oxide fuel cell stack.

According to the present invention, in the horizontally-striped solid oxide fuel cell stack, (a) lanthanum chromite or an interconnector mainly composed of lanthanum chromite is disposed among the anode layers disposed on the surface of the porous support substrate. The part to be used is an anode layer having a composition not containing zirconia (first anode layer), and (b) the part relating to the battery reaction is an anode layer having a composition not containing zirconia in common with the part in which the interconnector is arranged By forming an anode layer (second anode layer) having a composition containing zirconia on the (first anode layer),
Lanthanum chromite or interconnector material composed mainly of lanthanum chromite can be formed at a firing temperature of 1550 ° C or lower, especially in the range of 1450 ° C to 1500 ° C. , Voltage loss can be improved.

  Further, in the present invention, a horizontal stripe-type solid oxide fuel that can be formed with high yield, reproducibility, and an interconnector made of lanthanum chromite having these characteristics or a material mainly composed of lanthanum chromite. The stability and reliability of power generation by the battery stack can be improved.

  As described above, when lanthanum chromite is used as an interconnector material, high-temperature firing is required for dense sintering, but lanthanum chromite is used as an interconnector material with yttria-stabilized zirconia as an anode layer. When sintered at 1500 ° C. or lower, it was observed that the fuel gas leaked, and that the power generation efficiency was reduced or the temperature was increased due to combustion, causing destruction or deterioration. As a part of pursuing the cause, the interface and the vicinity thereof were observed with an electron microscope, and it was found that the denseness at the junction between the lanthanum chromite layer and the anode layer of Ni and yttria-stabilized zirconia was reduced. It was.

  FIG. 3 is the electron micrograph. As indicated by the oval frame as “dense density reduction” in FIG. 3, the interface between the dense Ni-yttria stabilized zirconia layer (labeled “zirconia” in FIG. 3) and the lanthanum chromite layer and Many relatively large holes are observed in the layer on the lanthanum chromite layer side from the interface.

  FIG. 4 is an enlarged view showing a portion indicated by a rectangular dotted line frame A in FIG. In addition, the “dense density reduction” portion corresponds to a portion indicated by a rectangular dotted frame B in FIG. A large number of relatively large holes generated in this portion cause fuel gas leakage, leading to a decrease in power generation efficiency and a breakdown or deterioration due to a temperature increase due to combustion.

  Therefore, in order to prevent lanthanum chromite, which is a constituent material of the interconnector, or a material mainly composed of lanthanum chromite and zirconia from contacting, the portion of the anode layer where (a) the interconnector is disposed does not include zirconia. The anode layer of the composition (first anode layer), and (b) the part involved in the battery reaction is the anode layer (first anode layer) of the composition not containing zirconia in common with the part where the interconnector is disposed The present invention has been completed by considering the use of an anode layer (second anode layer) having a composition containing zirconia laminated thereon and conducting an experiment from this viewpoint.

  FIG. 5 is a diagram for explaining the present invention in correspondence with FIG. As shown in FIG. 5, the anode layer (first anode layer) 2 having a composition not containing zirconia is used as the anode layer in the portion where the interconnector 6 made of lanthanum chromite or a material containing lanthanum chromite as a main component is disposed. The part of the anode layer concerned is formed into a double layer of an anode layer (second anode layer) 2 having a composition containing zirconia and an anode layer (first anode layer) 2 'having a composition not containing zirconia.

  The interconnector 6 is disposed on the upper surface of the anode layer (first anode layer) 2 ′ having a composition not containing zirconia. Further, the anode layer (second anode layer) 2 having a composition containing zirconia is disposed in a portion related to the battery reaction. That is, for the part related to the battery reaction, the anode layer (second anode layer) 2 having a composition containing zirconia is disposed on the upper surface of the anode layer (first anode layer) 2 'having a composition not containing zirconia. Then, an electrolyte layer 3 and a cathode layer 4 are sequentially arranged on the anode layer (second anode layer) 2 having a composition containing the zirconia to constitute a cell 5.

  In other words, as the material of the first anode layer in the portion where the interconnector 6 is disposed and the portion related to the battery reaction, a material different from the material that has been conventionally considered and used is used. The material which has been used is used only for the second anode layer of the part related to the battery reaction.

  In the present invention, lanthanum chromite, which is a constituent material of the interconnector 6, or a material mainly composed of lanthanum chromite is densely sintered by forming a layer related to the battery reaction when forming the anode layer. It is possible to do. This solves problems such as fuel gas leakage, a decrease in power generation efficiency associated therewith, and destruction and deterioration due to a temperature rise due to combustion.

  Here, the conditions required for the material of the “anode layer (first anode layer) not containing zirconia” in which lanthanum chromite or a material containing lanthanum chromite as a main component is arranged include (1) zirconia is included. (2) shrinkage rate, sinterability, and denseness are as close as possible to lanthanum chromite or a material containing lanthanum chromite as a main component, and (3) no reduction in the presence of high temperature and hydrogen. Therefore, any material satisfying the three conditions (1) to (3) can be used as the anode layer (first anode layer) 2 'having a composition not containing zirconia.

In the present invention, “Ni-containing Y ₂ O ₃ (yttria)” is effective as one of the materials of the “anode layer having a composition not containing zirconia (first anode layer)” that satisfies these conditions. I found.

Ni is for imparting a conductive path, that is, conductivity to Y ₂ O _3. From this viewpoint, the content of Ni in Y ₂ O ₃ containing Ni is 40 to 70% by volume (Y ₂ O ₃ and The ratio can be selected in the range of the ratio of the total amount of NiO. NiO, which is an oxide of Ni used as a raw material for the anode layer, has a role of bringing the shrinkage rate of the electrolyte material of the electrolyte layer 3 closer to that of the lanthanum chromite, and the fineness of the porous support substrate 1 when operating as a fuel cell. It becomes conductive by being reduced to Ni by the fuel gas that reaches the Y ₂ O ₃ layer containing NiO through the holes. Y ₂ O ₃ is not reduced. The amount of Ni in the anode layer can be measured by appropriately using a known method such as fluorescent X-ray analysis, EPMA, or ICP emission spectroscopic analysis.

  Further, in the horizontal stripe type solid oxide fuel cell stack of the present invention, (a) the lanthanum chromite or the lanthanum chromite is made of lanthanum chromite or lanthanum chromite having a thickness of the interconnector 6 made of a material mainly composed of lanthanum chromite and 20 μm or more. A gap is provided between the interconnector 6 made of a material as a main component and the anode layer 2 (second anode layer) having a composition containing zirconia in a portion related to the battery reaction, or (b) The interconnector 6 made of lanthanum chromite or a material containing lanthanum chromite as a main component has a thickness of 10 μm or more, and includes the interconnector 6 made of lanthanum chromite or a material containing lanthanum chromite as a main component, and zirconia in a part related to the battery reaction. Anode layer 2 of composition (second anode layer ), The interconnector 6 made of lanthanum chromite or a material containing lanthanum chromite as a main component, and the anode layer 2 having a composition containing zirconia in the part relating to the battery reaction, have good denseness. Is obtained.

In the present invention, among the constituent materials of the anode layer, materials containing zirconia include Ni and yttria stabilized zirconia [(Y ₂ O ₃ ) _X (ZrO ₂ ) _1-X (where X = 0.05 to 0.15)] is used, but the material is not limited thereto. In the case of a material made of a mixture of Ni and yttria-stabilized zirconia, a material in which Ni is dispersed in an amount of 40% by volume or more in the mixture is preferable.

In the present invention, as a constituent material of the porous support substrate 1, for example, 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 , etc. are used. It is not limited to these. Of these, a mixture of MgO and MgAl ₂ O ₄ is preferably a mixture of MgO and MgAl ₂ O ₄ which MgO is contained 20 to 70% by volume. Examples of zirconia-based oxides include yttria-stabilized zirconia [(Y ₂ O ₃ ) _X (ZrO ₂ ) _1-X (where X = 0.03 to 0.12)].

In the present invention, as the constituent material of the interconnector 6, an oxide represented by the formula (Ln, A) CrO ₃ (wherein Ln is a lanthanoid and A is Ba, Ca, Mg, or Sr) is used. This material is referred to herein as lanthanum chromite.

In addition, as a constituent material of the interconnector 6, lanthanum chromite may be appropriately added with auxiliary agents such as Al ₂ O ₃ and MgO, and this material is referred to as a material mainly composed of lanthanum chromite in this specification. ing.

In the present invention, yttria stabilized zirconia [(Y ₂ O ₃ ) _X (ZrO ₂ ) _1-X (where X = 0.05 to 0.15)] is used as a constituent material of the electrolyte layer 3.

Examples of the constituent material of the cathode layer 4 used in the present invention include the following materials (1) to (4), but are not limited thereto.
(1) (La, Sr) MnO ₃ -based materials such as La _0.6 Sr _0.4 Mn _1.0 O ₃ .
(2) (La, Sr) CoO ₃ -based materials such as La _0.6 Sr _0.4 Co _1.0 O ₃ .
(3) (La, Sr) CoFeO ₃ -based materials such as La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ and La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ .
(4) (La, Ca) MnO ₃ -based materials such as La _0.9 Ca _0.1 MnO ₃ .

  In the present invention, a heat-resistant and conductive material is used as the constituent material of the current collector 7, but the same material as the constituent material of the interconnector 6 may be used. The current collector 7 may not be denser than the interconnector 6, but may be denser.

<Manufacturing mode of horizontal stripe type solid oxide fuel cell stack>
The aspect of the method for producing the horizontal stripe solid oxide fuel cell stack according to the present invention (2) is as follows. The horizontal-striped solid oxide fuel cell stack of the present invention (1) is manufactured by the method of manufacturing the horizontal-striped solid oxide fuel cell stack of the present invention (2).

  (A) A porous material having a fuel flow path 8 inside when a horizontally striped solid oxide fuel cell stack is completed by selecting and using a suitable material from the constituent materials of the porous support substrate (see paragraph 0037). A quality support substrate 1 is formed.

(B) Among the constituent materials of the anode layer, as the material not containing the zirconia, a material composed of Y ₂ O ₃ containing Ni (see paragraph 0033) is used. Incidentally, in the material consisting of Y ₂ O ₃ containing Ni, Ni may also be included as NiO, and materials consisting of Y ₂ O ₃ containing Ni in the present invention, even materials consisting of Y ₂ O ₃ containing NiO Shall be included.
(B) 'Among the constituent materials of the anode layer, as the material containing the zirconia, a suitable material is selected from the materials containing the zirconia (see paragraph 0036 above) and used in the horizontal stripe type solid oxide fuel cell. Form an anode layer upon completion of the stack.
As the constituent material of the anode layer, two kinds of materials, ie, a material not containing zirconia and a material containing zirconia are used. Among these, the material that does not contain zirconia is the fuel at the time of completion of the horizontal stripe type solid oxide fuel cell stack among the surfaces that become the porous support substrate 1 at the time of completion of the horizontal stripe type solid oxide fuel cell stack. It arrange | positions in the surface opposite to the surface used as the flow path side, and arrange | positions the material containing a zirconia in the surface opposite to the surface of what becomes the porous support substrate 1 among the surfaces of the material which does not contain the said zirconia. .

  (C) An appropriate lanthanum chromite or a material containing lanthanum chromite as a main component is selected from the constituent materials of the interconnector 6 (see paragraphs 0038 and 0039), and the horizontal stripe type solid oxide fuel cell stack is used. Of the anode layer 2 'that does not contain zirconia at the time of completion, one that becomes the interconnector 6 at the time of completion of the horizontal stripe solid oxide fuel cell stack is formed on the surface of the anode layer 2' that does not contain zirconia.

  (D) A suitable material selected from the constituent materials of the electrolyte layer 3 (see paragraph 0040 above) is used to form both the anode layer and the horizontal stripe type when the horizontal stripe solid oxide fuel cell stack is completed. A layer that becomes the electrolyte layer 3 when the horizontal stripe solid oxide fuel cell stack is completed is formed so as to cover a portion other than a part of the upper surface of the interconnector 6 when the solid oxide fuel cell stack is completed.

  (E) At the time of completion of the horizontal stripe type solid oxide fuel cell stack, the porous support substrate 1, the anode layer, the interconnector 6, and the electrolyte layer 3 Are co-sintered.

  (F) An appropriate material is selected from the constituent materials of the cathode layer 4 (see paragraph 0041 above) and used to form the electrolyte layer 3 when the horizontal stripe solid oxide fuel cell stack is completed. When the horizontal solid oxide fuel cell stack is completed, the cathode layer 4 is formed at a position opposite to the anode layer 2 made of the material containing zirconia when the solid oxide fuel cell stack is completed. To do.

  In the step (f), it faces the anode layer when the horizontal stripe solid oxide fuel cell stack is completed through the electrolyte layer 3 when the horizontal stripe solid oxide fuel cell stack is completed. The portion is opposite to the constituent material of the cathode layer 4 and the anode layer 2 made of the material containing zirconia, with the portion that becomes the electrolyte layer 3 when the horizontal stripe solid oxide fuel cell stack is completed. Is formed.

  (G) An appropriate material selected from the constituent materials of the current collector 7 (see paragraph 0042 above) is used to form the cathode layer 4 when the horizontal stripe solid oxide fuel cell stack is completed. Between the interconnector 6 when the solid oxide fuel cell stack is completed, the current collector 7 is formed when the horizontal stripe solid oxide fuel cell stack is completed.

  The completed horizontal stripe solid oxide fuel cell stack thus formed is the horizontal stripe solid oxide fuel cell stack of the present invention (1).

  From this, in the horizontal stripe solid oxide fuel cell stack of the present invention (1), the porous support substrate described in (a) above is the completed horizontal stripe solid oxide fuel cell stack. In the porous support substrate 1, the material containing no zirconia as described in (b) and the material containing zirconia as described in (b) ′ serve as an anode layer in the completed horizontal-stripe solid oxide fuel cell stack, The interconnector described in (c) becomes the interconnector 6 in the completed horizontal stripe solid oxide fuel cell stack, and the electrolyte layer described in (d) becomes the completed horizontal stripe solid. In the oxide fuel cell stack, the electrolyte layer 3 and the cathode layer described in (f) are the completed horizontally-striped solid oxide fuel cell. The cathode layer 4 becomes in a stack, wherein those as a collector according to (g) as a collector 7 in the finished segmented-in-series solid oxide fuel cell stack.

  Anode (first anode layer) layer 2 ′ formed of a material not containing zirconia as described in (b) and an anode layer (second anode) formed of a material containing zirconia as described in (b) ′ The arrangement of the layer 2 is as shown in FIG.

  Summarizing the above process, “a plurality of cells composed of an anode layer, an electrolyte layer, and a cathode layer are sequentially formed on the surface of a porous support substrate having a fuel flow path therein, and between adjacent cells. Are connected in series via an interconnector made of lanthanum chromite or a material mainly composed of lanthanum chromite to produce a horizontally-striped solid oxide fuel cell stack. An anode layer (first anode layer) having a composition not containing zirconia is formed in a portion where the interconnector is disposed when the horizontally striped solid oxide fuel cell stack is completed. (B) Horizontally striped solid oxide When the physical fuel cell stack is completed, the part related to the cell reaction includes the same zirco as the part where the interconnector is arranged. An anode layer (second anode layer) containing zirconia is formed on an anode layer (first anode layer) having a composition containing no a. This is the present invention (2).

  And what was produced by the production method of the present invention (2) is the horizontal stripe solid oxide fuel cell stack of the present invention (1). A plurality of cells composed of an anode layer, an electrolyte layer and a cathode layer are formed on the surface of a porous support substrate, and between adjacent cells, lanthanum chromite or an interconnector made of lanthanum chromite as a main component is used. A horizontally striped solid oxide fuel cell stack electrically connected in series, wherein (a) a portion of the anode layer where the interconnector is disposed is an anode layer having a composition not containing zirconia ( The first anode layer), and (b) the part involved in the battery reaction is an alloy having a composition not containing zirconia in common with the part where the interconnector is disposed. A horizontally-striped solid oxide fuel cell stack characterized by comprising a cathode layer (first anode layer) and an anode layer (second anode layer) having a composition containing zirconia laminated thereon. Become.

  In the present specification, for the sake of convenience, for example, a porous support substrate at the time of completion as a horizontal stripe type solid oxide fuel cell stack is also provided for the formation process of each member when the horizontal stripe type solid oxide fuel cell stack is completed. The process of forming the product is also described as “forming a porous support substrate”, “forming a porous support substrate”, and the like. However, the formation process as a horizontal stripe type solid oxide fuel cell stack, that is, before completion, only the material that becomes the porous support substrate at the time of completion was arranged, and as a horizontal stripe type solid oxide fuel cell stack, It becomes a porous support substrate only when it is completed. In this regard, upon completion of the horizontal stripe type solid oxide fuel cell stack, forming an anode layer, forming an interconnector, forming an electrolyte layer, a cathode layer, The same applies to the formation of the current collector and the current collector.

  Hereinafter, the present invention will be described in more detail based on experimental examples, but the present invention is not limited to the experimental examples.

<Experimental example 1>
(1) Add nothing to the raw material powder of lanthanum chromite, (2) Add 1% by mass of zirconia powder (ratio in the total amount of raw material powder and additive, the same applies hereinafter), (3) Y ₂ O ₃ powder 4 types of (4) 1% by mass of NiO were added, pelletized by press molding, and fired at 1500 ° C. Ethanol was dropped into the pellet sample to test whether ethanol was impregnated.

  The results were as follows. The sample of (1) showed no penetration and was found to be densely sintered. Ethanol penetrated into the sample of (2). It was found that this sample did not become dense when fired at 1500 ° C. It was found that the samples of (3) and (4) were not sintered with ethanol as in (1), and were densely sintered.

These results show that lanthanum chromite becomes dense at a firing temperature of 1500 ° C., but zirconia inhibits the sinterability of lanthanum chromite, and Y ₂ O ₃ and NiO do not inhibit the sinterability of lanthanum chromite, It was confirmed that Y ₂ O ₃ and NiO were suitable as components of the anode layer (first anode layer) in contact with the lanthanum chromite layer.

<Experimental example 2>
In Experiment 2, a cross section of the anode layer (first anode layer) having a composition not containing zirconia added with 40% by volume of Ni (ratio in the total amount of Y ₂ O ₃ and NiO) was observed. FIG. 6 is an electron micrograph thereof. As shown in FIG. 6, it can be seen that the portion where the anode layer (first anode layer) having a composition not containing zirconia is disposed and the layers on both sides thereof have no large pores and have good denseness.

  Here, when the electron micrograph of FIG. 6 is compared with the electron micrograph of FIG. 3, in FIG. 3, the interface between the dense zirconia layer and the lanthanum chromite layer and the interface is relatively large from the interface to the lanthanum chromite layer side. Many holes were observed. On the other hand, in FIG. 6, almost no holes are observed on the lanthanum chromite layer side from the interface where the dense zirconia layer and the lanthanum chromite layer are in contact, and virtually no holes are found in each layer or boundary. Thus, the effect of the anode layer (first anode layer) having a composition not containing zirconia according to the present invention is clear.

<Experimental example 3>
In this experiment 3, (1) the thickness of the lanthanum chromite constituting the interconnector was changed, and (2) the anode layer (second anode layer, in this case, containing lanthanum chromite and zirconia in the part related to the battery reaction. Samples with different distances from the active layer (referred to as “active layer”) were prepared and tested for denseness in relation to the thickness a of lanthanum chromite and the distance b of the active layer. FIG. 7 shows the corresponding portions of the thickness a and the distance b, and Table 1 shows the test results.

  As shown in Table 1, the lanthanum chromite thickness a is 20 μm or more and there is a gap between the lanthanum chromite layer and the active layer (in this embodiment, the distance b is greater than 0 mm), When the thickness a is 10 μm or more and the distance b between the lanthanum chromite layer and the active layer is 2 mm or more, both the lanthanum chromite layer and the active layer have good denseness.

As described above, in the horizontally-striped solid oxide fuel cell stack, the interconnector 6 made of lanthanum chromite or a material mainly composed of lanthanum chromite and the portion where the interconnector is disposed do not include zirconia. A lanthanum chromite or a lanthanum chromite can be obtained by arranging an anode layer (first anode layer) 2 ′ having a composition and arranging an anode layer (second anode layer) 2 having a composition containing zirconia as a part relating to the cell reaction. It is possible to improve the denseness of the interface between the layer made of the material as the main component and the anode layer. A layer made of lanthanum chromite or a material containing lanthanum chromite as a main component that can withstand practical use can be formed by optimizing or optimizing the particle size range of Y ₂ O ₃ and the addition ratio of Ni.

  Further, according to the present invention, a dense thin film made of lanthanum chromite or a material containing lanthanum chromite as a main component has a problem such as significant shrinkage at 1550 ° C. or more. Can be formed with good reproducibility.

Diagram showing a configuration example of a hollow flat type horizontal stripe solid oxide fuel cell Diagram illustrating an example of a process for producing a horizontal stripe solid oxide fuel cell stack Electron micrograph of the interface between the solid electrolyte layer and the lanthanum chromite layer when lanthanum chromite is used as the interconnector material (drawing substitute photo) The figure which expanded and showed the part shown with the rectangular dotted-line frame A in FIG.1 (c). The figure explaining this invention corresponding to FIG. Electron micrograph (drawing substitute photo) observing a cross section of an intermediate layer in which 5 mass% of NiO is added to Y ₂ O ₃ The figure which shows the relationship of the thickness a of lanthanum chromite in <Experimental example 6>, and the distance b of lanthanum chromite and an active layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Porous support substrate 2 'Anode layer [Anode layer (1st anode layer) of a composition which does not contain zirconia]
2 Anode layer [Anode layer having a composition containing zirconia (second anode layer)]
3 Electrolyte layer 4 Cathode layer 5 Cell 6 Interconnector 7 Current collector (interconnector)
8 Fuel flow path a Thickness of lanthanum chromite b Distance between lanthanum chromite and active layer

Claims (9)

A plurality of cells composed of an anode layer, an electrolyte layer, and a cathode layer are arranged at intervals on the surface of a porous support substrate having a fuel flow path therein, and lanthanum chromite or lanthanum chromite is placed between adjacent cells. A horizontally-striped solid oxide fuel cell stack electrically connected in series via an interconnector made of a material as a main component,
Of the anode layer,
(A) The portion where the interconnector is disposed is an anode layer having a composition not containing zirconia,
(B) The part relating to the battery reaction is an anode layer having a composition not containing zirconia in common with the part where the interconnector is disposed, and an anode layer having a composition containing zirconia laminated thereon. Horizontally striped solid oxide fuel cell stack. In segmented-in-series solid oxide fuel cell stack according to claim 1, wherein the anode layer of the composition containing no zirconia in part the interconnector is disposed is made of Y ₂ O ₃ layer comprising Ni Horizontally striped solid oxide fuel cell stack. In segmented-in-series solid oxide fuel cell stack according to claim 2, segmented-in-series solid oxide, wherein the content of Ni in the Y ₂ O ₃ layer comprising the Ni is in the range of 40 to 70 volume% Physical fuel cell stack.   4. The horizontal stripe-type solid oxide fuel cell stack according to claim 1, wherein the interconnector has a thickness of 20 μm or more and contains a portion of zirconia involved in the battery reaction with the interconnector. 5. A horizontal-striped solid oxide fuel cell stack having a gap between the anode layer and the anode layer.   The horizontal stripe type solid oxide fuel cell stack according to any one of claims 1 to 3, wherein the interconnector has a thickness of 10 µm or more, and the interconnector and a portion of the zirconia involved in the battery reaction. A horizontal stripe-type solid oxide fuel cell stack, wherein the distance between the anode layer and the composition containing the anode layer is 2 mm or more. A plurality of cells composed of an anode layer, an electrolyte layer, and a cathode layer are formed at intervals on the surface of a porous support substrate having a fuel flow path therein, and lanthanum chromite or lanthanum chromite is formed between adjacent cells. When producing a horizontally-striped solid oxide fuel cell stack by electrically connecting in series via an interconnector made of the main component material,
Of the anode layer,
(A) An anode layer having a composition not containing zirconia is formed in a portion where the interconnector is disposed at the time of completion as a horizontal stripe type solid oxide fuel cell stack,
(B) At the time of completion as a laterally-clamped solid oxide fuel cell stack, zirconia is formed on the anode layer having a composition not containing zirconia in common with the portion where the interconnector is disposed in the portion related to the cell reaction. A method for producing a horizontal stripe solid oxide fuel cell stack, comprising forming an anode layer having a composition containing the anode layer. 7. The method for producing a horizontal stripe solid oxide fuel cell stack according to claim 6, wherein the anode layer having a composition not containing zirconia is formed of Y ₂ O ₃ containing Ni. A method for manufacturing a physical fuel cell stack. 8. The method of manufacturing a horizontal stripe type solid oxide fuel cell stack according to claim 7, wherein the firing for forming the anode layer made of Y ₂ O ₃ containing Ni is performed in a temperature range of 1450 ° C. to 1500 ° C. A manufacturing method of a horizontal stripe type solid oxide fuel cell stack. 9. The method for producing a horizontal stripe solid oxide fuel cell stack according to claim 7 or 8, wherein an addition amount of Ni in Y ₂ O ₃ containing Ni is in a range of 40 to 70% by volume. A method for producing a horizontal stripe solid oxide fuel cell stack.

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