JP2019216126A - Fuel battery cell and cell stack device - Google Patents

Abstract

To provide a fuel battery cell and a cell stack device that suppress deterioration caused by Cr from a manifold.SOLUTION: A fuel battery cell (100) of the present invention includes a lower end (101) supported by a manifold (200) formed from material containing Cr, the fuel battery cell comprising: a support board (110) including an external surface (112) extending vertically and a lower end surface (116) continuous to a lower end of the external surface (112); a power generation element part (120) that is provided on the external surface (112) and includes a fuel electrode (130), electrolyte (140), and air electrode (150); and a coating part (170) that covers at least part of the lower end surface (116) and is constituted by a compound containing Cr.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a fuel cell and a cell stack device.

Conventionally, a cell stack device including a manifold, a plurality of fuel cells extending upward from the manifold, and a bonding material for bonding the manifold and the fuel cells has been known. As such a cell stack device, for example, WO 2016/158684 (Patent Document 1) is cited.

The cell stack device of Patent Literature 1 has a frame body on which one end of a fuel cell is fixed by a sealing material on the inside, and a plate-shaped body joined to one end of the frame body and having lower rigidity than the frame body. It is disclosed to provide a manifold having: Further, it is disclosed that ferrite-based stainless steel or the like is used as a material of a frame body and a plate-like body constituting the manifold of Patent Document 1.

International Publication No. WO 2016/158684

When the cell stack device including the manifold disclosed in Patent Document 1 is operated, chromium (Cr) of stainless steel constituting the manifold may be released and adhere to the sealing material. In this case, the insulating property of the sealing material decreases, and the sealing material deteriorates.

In view of the above problems, it is an object of the present invention to provide a fuel cell which suppresses deterioration of a manifold due to Cr when used in a cell stack device. Another object is to provide a cell stack device that suppresses deterioration due to Cr.

As a result of intensive studies to solve the above-described problems, the present inventors have completed the present invention by focusing on efficiently collecting Cr released from the manifold in a region where the influence is small in the fuel cell.

That is, the present invention is a fuel cell in which a lower end is supported on a manifold made of a material containing chromium, and has an outer surface extending vertically and a lower end surface connected to a lower end of the outer surface. A supporting substrate, provided on the outer surface, a fuel electrode, an electrolyte, and a power generation element portion having an air electrode, and covering at least a part of the lower end surface, and including a coating portion made of a compound containing chromium. ing.

According to the present invention, the covering portion made of a compound containing Cr is formed on at least a part of the lower end surface of the fuel cell. Since the covering portion is made of a compound containing Cr, the covering portion functions as a getter material for capturing Cr. Since this covering portion is formed on the lower end surface of the supporting substrate relatively close to the manifold, Cr can be efficiently captured. For this reason, it is possible to suppress the Cr released from the manifold from adhering to the joining material joining the lower end portion of the fuel cell unit and the manifold of the present invention. As a result, a decrease in the insulating property of the bonding material can be suppressed. Further, even if Cr is collected on the lower end surface of the support substrate, the influence is small. Therefore, when the fuel cell of the present invention is used in a cell stack device, deterioration of the manifold due to Cr can be suppressed.

In the fuel cell of the present invention, the lower end surface may include the C plane. Further, in the fuel cell unit of the present invention, the lower end surface may be curved upward or downward. By controlling the form of the fuel cell in this manner, the covering portion can be easily formed on the lower end surface of the support substrate.

The cell stack device of the present invention includes the fuel cell described above, a manifold that supports the lower end of the fuel cell, and is made of a material containing chromium, and a joining material that joins the manifold and the fuel cell. , Is provided.

ADVANTAGE OF THE INVENTION According to the cell stack apparatus of this invention, Cr from a manifold can be collected in the coating | coated part formed in the lower end surface of a support substrate. For this reason, it can control that Cr adheres to a joining material. Therefore, deterioration due to Cr from the manifold can be suppressed.

As described above, the present invention can provide a fuel cell that suppresses deterioration due to Cr from a manifold when used in a cell stack device. Further, a cell stack device that suppresses deterioration due to Cr can be provided.

FIG. 2 is a perspective view showing the cell stack device according to the first embodiment. FIG. 2 is a cross-sectional view illustrating the cell stack device according to the first embodiment. FIG. 2 is a cross-sectional view illustrating the cell stack device according to the first embodiment. FIG. 2 is a perspective view showing the fuel cell unit according to the first embodiment. FIG. 2 is a cross-sectional view illustrating the fuel cell unit according to the first embodiment. FIG. 2 is an enlarged sectional view showing the cell stack device according to the first embodiment. FIG. 2 is another enlarged sectional view showing the cell stack device of the first embodiment. FIG. 2 is another enlarged sectional view showing the cell stack device of the first embodiment. FIG. 4 is a cross-sectional view illustrating the method for manufacturing the cell stack device of the first embodiment. FIG. 4 is a cross-sectional view illustrating the method for manufacturing the cell stack device of the first embodiment. FIG. 8 is a schematic diagram illustrating a fuel cell and a bonding material that constitute a cell stack device according to a second embodiment. FIG. 9 is a schematic diagram illustrating a fuel cell and a bonding material that constitute a cell stack device according to a third embodiment. FIG. 14 is a schematic diagram illustrating a cross section of a fuel cell and a bonding material that constitute a cell stack device according to a fourth embodiment. FIG. 14 is a schematic diagram illustrating a cross section of a fuel cell and a bonding material constituting a cell stack device according to a fifth embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The x-axis direction in each figure,
Each of the y-axis direction and the z-axis direction is a height direction, a short direction (width direction) of the manifold,
And the longitudinal direction. Further, each of the x-axis direction, the y-axis direction, and the z-axis direction in each drawing corresponds to the longitudinal direction, the lateral direction (width direction), and the thickness direction of each fuel cell and the support substrate. The terms “up” and “down” in this specification are based on the height direction (x-axis direction) of the manifold when the manifold and the cell stack device are placed on a horizontal plane.

(Embodiment 1)
With reference to FIGS. 1 to 6, a cell stack device and a fuel cell unit according to an embodiment of the present invention will be described. The cell stack device and the fuel cell according to the first embodiment are used for a solid oxide fuel cell (SOFC: Solid Oxide Fuel Cell).

[Cell stack device]
As shown in FIGS. 1 to 3, the cell stack device 1 includes a plurality of fuel cells 100, a manifold 200, and a first bonding material 300. Each fuel cell 100 is supported by a manifold 200. The first bonding material 300 includes each fuel cell 100,
The manifold 200 is joined.

[Fuel cell]
As shown in FIGS. 1 to 3, the fuel cell 100 extends upward from the manifold 200. Specifically, as shown in FIG. 2, each fuel cell 100 extends upward from the upper wall 230 of the manifold 200. The lower end portion 101 of the fuel cell 100 is inserted into the insertion hole 231 of the manifold 200. When the lower end portion 101 of the fuel cell 100 is inserted into the insertion hole 231, a gap is formed between the outer peripheral surface of the lower end portion 101 of the fuel cell 100 and the inner wall surface of the insertion hole 231. I have. The first joining material 300 is inserted into this gap.
Is filled. For this reason, the lower end portion 101 of the fuel cell 100 is
It is fixed to 0. On the other hand, the upper end 102 of the fuel cell 100 is a free end. The fuel cell 100 is supported by the manifold 200 in a cantilever state, and is self-supporting.

The fuel cells 100 are spaced from each other along the longitudinal direction of the manifold 200. The fuel cells 100 are electrically connected to each other via the first current collecting member 4. The first current collecting member 4 is disposed between the fuel cells 100, and connects the adjacent fuel cells 100. Note that the first current collecting member 4 is joined to each fuel cell 100 by the second joining material 5. The first current collecting member 4 is formed of a conductive material. The first current collecting member 4 is formed of, for example, a fired body of an oxide ceramic or a metal.

As shown in FIGS. 2 to 4, the fuel cell 100 includes a support substrate 110, a plurality of power generation elements 120, and a cover 170. Each power generation element unit 120 is supported on both surfaces of the support substrate 110. Note that each power generation element unit 120 may be supported on only one surface of the support substrate 110. The power generating elements 120 are spaced from each other in the longitudinal direction of the fuel cell 100. That is, the fuel cell 100 according to the present embodiment
This is a so-called horizontal stripe fuel cell.

Each power generation element unit 120 is electrically connected to each other by an electric connection unit 160 (see FIG. 5). Further, on the upper end 102 side of the fuel cell 100, the power generation element unit 120 formed on one surface of the support substrate 110 and the power generation element unit 120 formed on the other surface are connected to the second current collecting member 6 (see FIG. 2). ) Are electrically connected. The power generating elements 120 are connected in series.

<Support substrate>
As shown in FIG. 3, the support substrate 110 has therein a plurality of gas channels 111 extending in the longitudinal direction (vertical direction) of the fuel cell 100. The gas passage 111 is connected to the manifold 20.
It communicates with the internal space of the manifold 200 through the zero insertion hole 231.

The longitudinal direction of the support substrate 110 is the same as the longitudinal direction of the fuel cell 100. Each gas flow path 111 extends substantially parallel to each other. Each gas flow path 111 is open at both ends in the longitudinal direction of the fuel cell 100.

The support substrate 110 may be conductive or insulative. When the support substrate 110 is insulative, the support substrate 110 is formed of, for example, ceramics. Specifically, the support substrate 110 may be made of CSZ (calcia-stabilized zirconia),
It may be composed of iO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia), may be composed of NiO and Y ₂ O ₃ (yttrium oxide), and may be M.
It may be composed of gO (magnesium oxide) and MgAl ₂ O ₄ (magnesia alumina spinel). The support substrate 110 is porous. The porosity of the support substrate 110 is, for example,
20 to 60%.

The support substrate 110 has an outer surface 112 extending vertically, a lower end surface 116 connected to the lower end of the outer surface 112, and an upper end surface 117 connected to the upper end of the outer surface 112.

The support substrate 110 of the present embodiment is a flat cylindrical flat plate extending in the longitudinal direction. Therefore, as shown in FIG. 4, the support substrate 110 includes a first main surface 113, a second main surface 114 opposite to the first main surface 113, a first main surface 113, and a second main surface 114. Pair of side end surfaces 1 for connecting
15. The first main surface 113, the second main surface 114, and the pair of side end surfaces 115 form an outer surface of the support substrate 110. The first main surface 113 and the second main surface 114 form a gas flow path 111.
And extend in parallel with each other. The distance between the first main surface 113 and the second main surface 114, that is, the thickness of the support substrate 110 is, for example, 1 to 10 mm. The pair of side end surfaces 115 are both ends in the width direction. The first main surface 113 and the second main surface 114 are flat, and a pair of side end surfaces 115
Is a curved surface.

The lower end surface 116 is continuous with the lower ends of the first main surface 113, the second main surface 114, and the pair of side end surfaces 115. The lower end surface 116 is a surface facing downward. Specifically, the lower end surface 116 is a surface located at the lower end of the support substrate 110 and extending in a direction intersecting the vertical direction. The upper end face 117 is
The first main surface 113, the second main surface 114, and the upper ends of the pair of side end surfaces 115 are continuous. The upper end surface 117 is a surface facing upward. The lower end face 116 located at the lower end and the upper end face 117 located at the upper end face each other. An inlet of the gas flow path 111 is formed on the lower end face 116, and an outlet of the gas flow path 111 is formed on the upper end face 117.

As shown in FIG. 5, the outer surface 112 of the support substrate 110 has a plurality of first concave portions 112a. Each of the first concave portions 112a is formed on both surfaces of the support substrate 110 (the first main surface 113 and the second main surface 1).
14). The first recesses 112a are formed at an interval from each other in the longitudinal direction of the support substrate 110.

<Power generation element part>
As shown in FIG. 5, each power generation element unit 120 has a fuel electrode 130, an electrolyte 140, and an air electrode 150. Each power generation element unit 120 further has a reaction prevention film 121.

Specifically, the fuel electrode 130 is a fired body made of a porous material having electron conductivity. The anode 130 has an anode current collector 131 and an anode active unit 132. The fuel electrode current collector 131 is disposed in the first recess 112a. Each anode current collector 131 is a second
It has a recess 131a and a third recess 131b. The anode active portion 132 is provided in the second recess 13.
1a.

The fuel electrode current collector 131 may be composed of, for example, NiO and YSZ, may be composed of NiO and Y ₂ O ₃ , or may be composed of NiO and CSZ. The thickness of the fuel electrode current collector 131, that is, the depth of the first recess 112a is, for example, 50 to 500 μm.

The fuel electrode active part 132 may be composed of, for example, NiO and YSZ, or may be composed of NiO and GDC = (Ce, Gd) O ₂ (gadolinium-doped ceria). The thickness of the fuel electrode active portion 132 is, for example, 5 to 30 μm.

The electrolyte 140 is arranged so as to cover the fuel electrode 130. Specifically, the electrolyte 14
0 indicates the number of fuel cells 1 from one interconnector 161 to another interconnector 161
00 in the longitudinal direction. That is, the electrolytes 140 and the interconnectors 161 are alternately arranged in the longitudinal direction of the fuel cell 100.

The electrolyte 140 is a fired body made of a dense material having ion conductivity and no electron conductivity. The electrolyte 140 may be composed of, for example, YSZ or LSG
M (lanthanum gallate) may be used. The thickness of the electrolyte 140 is, for example, 3 to 5
0 μm.

The reaction prevention film 121 is a fired body made of a dense material, has substantially the same shape as the fuel electrode active portion 132 in a plan view, and is disposed at substantially the same position as the fuel electrode active portion 132. The reaction prevention film 121 prevents the occurrence of a phenomenon in which YSZ in the electrolyte 140 reacts with Sr (strontium) in the air electrode 150 to form a reaction layer having high electric resistance at the interface between the electrolyte 140 and the air electrode 150. It is provided to control. The reaction prevention film 121 is made of, for example, G
It consists of DC. The thickness of the reaction prevention film 121 is, for example, 3 to 50 μm.

The air electrode 150 is disposed on the reaction prevention film 121. The air electrode 150 is a fired body made of a porous material having electron conductivity. The air electrode 150 is, for example, LSCF
= (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite),
LSF = (La, Sr) FeO ₃ (lanthanum strontium ferrite), LNF = La
(Ni, Fe) O ₃ (lanthanum nickel ferrite), LSC = (La, Sr) CoO ₃
(Lanthanum strontium cobaltite) or the like. In addition, the air electrode 150
Is the first layer (inner layer) composed of LSCF and the second layer (outer layer) composed of LSC
And two layers. The thickness of the air electrode 150 is, for example, 10 to 100 μm.
It is.

The electrical connection section 160 is configured to electrically connect the adjacent power generation element sections 120. The electrical connection section 160 has an interconnector 161 and an air electrode current collecting film 162. The interconnector 161 is arranged in the third recess 131b. The interconnector 161 is a fired body made of a dense material having electron conductivity. The interconnector 161 may be made of, for example, LaCrO ₃ (lanthanum chromite),
(Sr, La) TiO ₃ (strontium titanate) may be used. The thickness of the interconnector 161 is, for example, 10 to 100 μm.

The air electrode current collecting film 162 is disposed so as to extend between the interconnector 161 of the adjacent power generation element unit 120 and the air electrode 150. The cathode current collecting film 162 is a fired body made of a porous material having electron conductivity. The air electrode current collecting film 162 is, for example, LSCF = (
La, Sr) (Co, Fe) O ₃ or LSC = (La, Sr) Co
It may be composed of O _3, or may be composed of Ag (silver) or Ag-Pd (silver-palladium alloy). The thickness of the cathode current collecting film 162 is, for example, 50 to 500 μm.

As shown in FIG. 6, the lower end portion 101 of the fuel cell 100 is covered with a dense film 122. Specifically, the dense film 122 covers the support substrate 110. The dense film 122
It is electrically connected to the power generation element unit 120 formed on the lower end side. Specifically, the dense membrane 1
Reference numeral 22 is electrically connected to the electrical connection unit 160. The dense film 122 extends from between the air electrode current collecting film 162 and the support substrate 110 toward the proximal side.

The dense film 122 exerts a gas sealing function of preventing the fuel gas flowing in the space inside the dense film 122 from mixing with the air flowing in the space outside the dense film 122. In order to exhibit the gas sealing function, the porosity of the dense film 122 is, for example, 10% or less. The dense film 122 is made of an insulating ceramic.

Specifically, the dense film 122 can be composed of the electrolyte 140 and the reaction prevention film 121 described above. The electrolyte 140 constituting the dense film 122 covers the support substrate 110 and extends from the interconnector 161 to near the lower end of the support substrate 110. Further, the reaction prevention film 121 constituting the dense film 122 is disposed between the electrolyte 140 and the air electrode current collecting film 162. Note that the dense film 122 may be composed of only the electrolyte 140,
It may be made of a material other than the electrolyte 140 and the reaction prevention film 121.

<Coating part>
As shown in FIGS. 2 to 4 and 6, a covering portion 170 is formed so as to cover at least a part of the lower end surface 116 of the support substrate 110. The covering section 170 is exposed in the internal space of the manifold 200.

The coating 170 is a Cr getter material that captures Cr. The covering section 170 is made of a compound containing Cr. The compound containing Cr is a substance in which a Cr element and one or more other elements are chemically bonded. For example, chromium oxide (CrO, Cr ₂ O ₃ , CrO ₃ ), magnesium chromate (CrMgO ₄ ), chromium Nickel acid (CrNiO ₄ , Cr ₂ NiO ₇ ),
Aluminum chromate (Al ₂ (CrO ₄ ) ₃ ), strontium chromate (SrCrO)
₄ ) and the like. The covering portion 170 is preferably formed of a material containing a substance in which at least one of the O (oxygen) element and the element included in the support substrate 110 and the Cr element are chemically bonded.

The covering portion 170 covers at least a part of the lower end surface 116 of the support substrate 110, and
, The entire periphery of the outer peripheral portion of the lower end surface 116 is covered. In addition, the covering section 170 is
May be entirely coated. As shown in FIG. 6, the covering portion 170 covers the entire lower end surface 116 in a cross-sectional view in the width direction (z-axis direction) including the gas flow path 111.

Furthermore, the covering portion 170 may be formed near the lower end surface 116 located below the power generation element portion 120 on the outer surface 112. Further, the covering portion 170 is formed by the first bonding material 300.
May be formed on a part of the exposed surface 301 of the first bonding material 300.
It is not formed on the entire exposed surface 301 exposed to zero. The covering part 170 is formed of the first bonding material 30.
Preferably, it is not formed at zero. That is, it is preferable that the covering portion 170 is formed only near the lower end surface 116 of the support substrate 110.

The covering section 170 is in the form of a film. The thickness of the covering portion 170 may be constant as shown in FIG. 6 or may not be constant. The maximum thickness of the coating portion 170 is, for example, 0.1 μm to 10 μm.
m.

The covering section 170 may be composed of one layer, or may be composed of a plurality of layers formed of different materials. Further, the covering portion 170 may be a single continuous member or a plurality of members separately formed in a plurality of regions.

The covering portion 170 is provided directly or indirectly on at least a part of the lower end surface 116 of the support substrate 110. Specifically, the covering section 170 may be in contact with the lower end surface 116 of the support substrate 110 as shown in FIG. 6, or may be attached via the intermediate layer 180 as shown in FIG. . In the case of FIG. 7, the fuel cell unit 100 includes an intermediate layer 180 formed so as to be in contact with the lower end surface 116 of the support substrate 110, and a covering portion 170 formed so as to be in contact with the intermediate layer 180.

The intermediate layer 180 has, for example, a role of bonding the lower end surface 116 and the cover 170.
The intermediate layer 180 is made of, for example, glass, ceramics, or the like, and is preferably glass. As the glass, for example, crystallized glass can be used. As the crystallized glass, for example, SiO ₂ —B ₂ O ₃ system, SiO ₂ —CaO system, or SiO ₂ —M
A gO system may be employed. In the present specification, the term “crystallized glass” means that the ratio of the “volume occupied by the crystal phase” to the total volume (crystallinity) is 60% or more, and the “volume occupied by the amorphous phase and impurities” to the total volume. "Means less than 40% of the glass. In addition, as a material of the intermediate layer 180, amorphous glass, brazing material, ceramics, or the like may be employed. Specifically, the intermediate layer 180 is made of a SiO ₂ —MgO—B ₂ O ₅ —Al ₂ O ₃ system and a SiO ₂ —MgO—
It is at least one selected from the group consisting of Al ₂ O ₃ —ZnO. The intermediate layer 18
0 may be a different material from the first bonding material 300 or may be the same material.

[Manifold]
As shown in FIGS. 1 to 3, the manifold 200 supplies a reaction gas to the fuel cell 100. The manifold 200 is hollow and has an internal space. As shown in FIG. 1, a fuel gas is supplied to the internal space of the manifold 200 via an introduction pipe P. As shown in FIG. 2, the manifold 200 has a plurality of insertion holes 231 for communicating the internal space with the outside.

The manifold 200 has a substantially rectangular parallelepiped shape. As shown in FIG.
00 includes a bottom wall 210, a side wall 220, an upper wall 230, and a flange 240.

The bottom wall 210, the side wall 220, and the flange 240 are integrally formed. The bottom wall 210, the side wall 220, and the flange portion 240, which are integrally formed, and the upper wall 230 are separate members and are joined to each other. The bottom wall 210, the side wall 220, the upper wall 230, and the flange 240 are formed of a material containing Cr, and are made of, for example, a metal having heat resistance. Such a metal is, for example, stainless steel.

The bottom wall 210 has a rectangular shape in plan view (in the x-axis direction). The side wall 220 extends upward from the outer peripheral portion of the bottom wall 210. The flange 240 extends outward from the upper end of the side wall 220. The flange 240 is annular.

The upper wall 230 is configured to close the upper end of the side wall 220. Specifically, the upper wall 2
The outer periphery of 30 is disposed on flange 240. In order to seal the internal space of the manifold 200, the upper wall 230 is joined to the flange 240 over the entire circumference. The upper wall 230 is joined to the flange 240 by, for example, a joining material or welding.

As shown in FIG. 2, the upper wall 230 has a plurality of insertion holes 231 into which the fuel cells 100 are inserted. Each insertion hole 231 extends in the width direction (y-axis direction) of the manifold 200. Further, the insertion holes 231 are arranged at intervals in the longitudinal direction of the manifold 200.

[First joining material]
The first bonding material 300 fixes the fuel cell 100 to the manifold 200. Specifically, the first joining material 300 joins the lower end portion 101 of the fuel cell 100 and the upper wall 230 of the manifold 200. The first bonding material 300 is in contact with the dense film 122. In a state where the fuel cell 100 is fixed to the manifold 200, the insertion hole 231 is formed.
And the gas flow path 111 communicate with each other.

The first bonding material 300 includes an inner space of the manifold 200 (a space exposed to fuel gas),
By partitioning the outside of the cell stack device 1 (a space exposed to a gas containing oxygen), the cell stack device 1 has a function of preventing mixing of a fuel gas and a gas containing oxygen. For this reason,
As shown in FIGS. 6 and 7, the first bonding material 300 has an exposed surface 3 which is a surface exposed to the fuel gas.
01 and an outer surface 302 exposed to a gas containing oxygen. The exposed surface 301 is
It is exposed in the internal space of the manifold 200. The outer surface 302 is exposed outside the cell stack device 1.

The first bonding material 300 is, for example, crystallized glass. As the crystallized glass, for example,
A SiO ₂ —B ₂ O ₃ system, a SiO ₂ —CaO system, or a SiO ₂ —MgO system may be employed. As a material of the first bonding material 300, amorphous glass, brazing material, ceramics, or the like may be employed. Specifically, the first bonding material 300 is made of SiO ₂ —MgO—B ₂ O ₅ —Al ₂
It is at least one selected from the group consisting of an O ₃ system and a SiO ₂ —MgO—Al ₂ O ₃ —ZnO system.

The exposed surface 301 of the first bonding material 300 shown in FIGS.
6 is located above. As shown in FIG. 8, the exposed surface 301 of the first bonding material 300
It may be located on the same plane as the lower end surface 116 of the support substrate 110. Therefore, the covering portion 170 shown in FIGS. 6 to 8 is located below the exposed surface 301. As described above, it is preferable that the lower end surface 171 of the covering portion 170 be located below the exposed surface 301. Further, it is preferable that the covering portion 170 and the first bonding material 300 are separated from each other. 6 to 8.
Here, the exposed surface 301 and the lower end surface 171 are schematically shown as flat surfaces, but in reality, irregularities are formed.

[Production method]
Subsequently, a method for manufacturing the cell stack device 1 of the present embodiment will be described with reference to FIGS.

First, as shown in FIG. 9, a cell body 10 having a power generation element section 120 formed on a support substrate 110 is formed.
Prepare a plurality of 3. Next, a covering portion 170 is formed on the lower end surface 116 of the support substrate 110.
In this step, for example, a paste containing a compound containing Cr is applied to lower end surface 116 of support substrate 110, and heat is applied to the paste. When forming the covering portion 170 having a plurality of layers, a material for each layer is formed on the lower end surface 116.

Also, a manifold 200 is prepared. Then, the respective cell bodies 103 are connected to each other by a material to be the first current collecting member 4 and the second bonding material 5, and the cell assembly 104 is manufactured. At this stage, the second bonding material 5 is not fired, and the respective cell bodies 103 are temporarily fixed to each other.

Next, as shown in FIG. 10, the lower end portion 101 of each cell body of the cell assembly 104 is inserted into each insertion hole 231 of the manifold 200. Note that a jig for holding the cells 103 at a predetermined interval along the thickness direction may be used.

Next, as shown in FIG. 2, the cell body 103 inserted into the insertion hole 231 and the manifold 20
A material to be the first bonding material 300 is applied so as to bond the upper wall 230 to the first bonding material 300.

Next, a heat treatment is applied to the materials to be the first bonding material 300 and the second bonding material 5. By this heat treatment, the first bonding material 300 and the second bonding material 5 are solidified. Specifically, the second bonding material 5 is fired by performing a heat treatment. As a result, each fuel cell 100
And the first current collecting member 4 are fixed. The material that becomes the first bonding material 300 is subjected to a heat treatment, so that the temperature of the amorphous material reaches the crystallization temperature. Then, a crystal phase is generated inside the material at the crystallization temperature, and crystallization proceeds. As a result, the amorphous material is solidified and turned into ceramics to form crystallized glass. Thereby, the first bonding material 300 made of crystallized glass exhibits a function, and the lower end portion 101 of each fuel cell 100 is fixed to the upper wall 230 of the manifold 200.

Note that the step of applying heat to the paste to be the covering portion 170 may be the same step as the heat treatment of the first bonding material 300 and the second bonding material 5, or may be a separate step.

By performing the above steps, the fuel cell 100 and the cell stack device 1 shown in FIGS. 1 to 8 can be manufactured.

[motion]
The operation of the cell stack device 1 according to the present embodiment will be described with reference to FIGS.
The cell stack device 1 operates, for example, as follows.

The fuel gas (hydrogen gas or the like) flows into the gas flow path 111 of each fuel cell 100 via the manifold 200, and both surfaces of the support substrate 110 are exposed to a gas containing oxygen (air or the like), thereby forming the electrolyte 140. An electromotive force is generated by the oxygen partial pressure difference generated between both side surfaces. When the cell stack device 1 is connected to an external load, an electrochemical reaction represented by the following formula 1 occurs at the air electrode 150, and an electrochemical reaction represented by the following formula 2 occurs at the fuel electrode 130.
(1/2) O ₂ + 2e ⁻ → O ^2- (Formula 1)
^{_{H 2 + O 2- → H 2}} O + 2e - ··· ( Formula 2)
Further, of the fuel gas flowing through the gas flow path 111 of the support substrate 110, surplus fuel gas not used for power generation is discharged to the outside from a discharge port located at the other end of the gas flow path 111.
Then, the excess fuel gas discharged from the outlet and the gas containing oxygen are mixed and burned.

[effect]
As described above, the fuel cell unit 100 and the cell stack device 1 of the present embodiment
A support substrate 110 having an outer surface 112 extending in a vertical direction, a lower end surface 116 continuing to a lower end of the outer surface 112, a fuel electrode 130, an electrolyte 14
A power generation element unit 120 having the air electrode 150 and the air electrode 150, and a coating unit 170 that covers at least a part of the lower end surface 116 of the support substrate 110 and is made of a compound containing Cr.

When the temperature becomes high due to the heat treatment step in the manufacturing process of the cell stack apparatus 1 described above, the operation of the cell stack apparatus 1, and the like, the bottom wall 210, the side wall 220,
Cr constituting at least one of the upper wall 230 and the flange 240 may be released. The released Cr is exposed to the internal space of the manifold 200 and adheres preferentially to the coating portion 170 as a Cr getter provided at a position closest to the manifold 200. Since the released Cr can be efficiently collected in the covering portion 170, the first bonding material 3
It is possible to prevent Cr from adhering to the other regions such as 00 and the power generation element section 120. By suppressing the adhesion of Cr to the first joining material 300, it is possible to suppress a decrease in the insulating property and a decrease in strength of the first joining material 300. In addition, by suppressing the adhesion of Cr to the power generation element unit 120, deterioration in performance can be suppressed, and in particular, so-called Cr poisoning of the air electrode 150 can be suppressed. Furthermore, since the power generating element 120 is not formed on the lower end surface 116 of the fuel cell 100, even if Cr adheres, the influence is small. Therefore, deterioration of the fuel cell 100 and the first bonding material 300 can be suppressed. Therefore, the fuel cell unit 100 and the cell stack device 1 of the present embodiment can suppress deterioration due to Cr from the manifold.

(Embodiment 2)
The fuel cell and the cell stack device 1a according to the second embodiment shown in FIG. 11 basically have the same configuration as the fuel cell and the cell stack device 1 according to the first embodiment. Is different from the exposed surface 301 of the first bonding material 300 in that the lower end surface 171 is located at the same position in the vertical direction. That is, the exposed surface 301 and the lower end surface 171 are
Located on the same plane. FIG. 11 schematically shows the covering portion 170 and the first bonding material 300, and the exposed surface 301 and the lower end surface 171 are schematically shown as planes.
Actually, irregularities are formed. 12 to 14 schematically showing the covering portion 170 and the first bonding material 300 in the fuel cell units and the cell stack devices according to Embodiments 3 to 5 described later.

(Embodiment 3)
The fuel cell and the cell stack device 1b according to the third embodiment shown in FIG. 12 basically have the same configuration as the fuel cell and the cell stack device 1a according to the second embodiment. The lower end surface 116 of the support substrate 110 includes a C surface 116a, and is different in that a covering portion 170 is formed below the C surface 116a.

Specifically, the lower end surface 116 of the support substrate 110 has a horizontal surface 116b extending in the horizontal direction,
The horizontal plane 116b is connected to the C plane 116a. The horizontal surface 116b is connected to the gas flow path 11
1 to the outer surface 112 side. The C surface 116a is formed by chamfering a corner portion connected to the outer surface 112. The “C-plane” is a plane obtained by chamfering a ridge formed by the planes into a plane.

The lower end surface 171 of the covering portion 170 formed below the C surface 116a is located on the same plane as the horizontal surface 116b. Therefore, the thickness of the covering portion 170 increases in a tapered shape toward the outer surface 112.

Note that the covering section 170 may further cover at least a part of the horizontal surface 116b.
Further, the lower end surface of the support substrate of the present invention may include an R surface instead of the C surface. "R side"
Is a surface (arc surface) obtained by chamfering a ridge line formed by the surfaces into an arc shape convex outward or inward.

(Embodiment 4)
The fuel cell unit and the cell stack device 1c according to the fourth embodiment shown in FIG. 13 basically have the same configuration as the fuel cell unit and the cell stack device 1 according to the second embodiment. Is different in that the lower end surface 116 of the support substrate 110 is curved upward. That is, the lower end surface 116 has an upward arc shape.

A covering portion 170 is formed below the curved lower end surface 116. The lower end surface 171 of the covering portion 170 is located on the same plane as the corner of the lower end surface 116 of the support substrate 110.
For this reason, the thickness of the covering portion 170 increases from the corner to the center.

(Embodiment 5)
The fuel cell unit and the cell stack apparatus 1d according to the fifth embodiment shown in FIG. 14 basically have the same configuration as the fuel cell unit and the cell stack apparatus 1 according to the second embodiment. Is different in that the lower end surface 116 of the support substrate 110 is curved downward. That is, the lower end surface 116 has a downward arc shape.

A covering portion 170 is formed below the curved lower end surface 116. The lower end surface 171 of the covering portion 170 is located on the same plane as the center of the lower end surface 116 of the support substrate 110. For this reason, the thickness of the covering portion 170 decreases from the corner to the center.

The fuel cell and cell stack devices 1c and 1d according to the fourth and fifth embodiments are
This has an advantage in manufacturing that the covering portion 170 can be easily formed on the lower end surface 116 of the zero.

(Modification)
Here, the cell stack devices of the above-described first to fifth embodiments have been described by taking as an example a horizontal stripe type in which a plurality of power generation element units 120 are arranged on one main surface of the support substrate 110. May be a vertical stripe type in which one power generation element is arranged on one main surface of a support substrate. In addition, the cell stack apparatus according to the first to fifth embodiments has a cylindrical flat plate-shaped support substrate 110.
However, the cell stack device of the present invention may include a cylindrical support substrate.

Although the manifold 200 according to the first to fifth embodiments has a structure in which the upper surface of the side wall 220 is open and the upper surface is closed by the upper wall 230, the manifold of the present invention is not limited to this. For example, a structure in which the side wall and the upper wall are integrated, the lower end surface of the side wall is opened, and the lower end surface is closed by the bottom wall may be employed.

In the manifolds 200 of the first to fifth embodiments, the side wall 220 extends substantially vertically upward from the bottom wall 210, but the manifold of the present invention is not limited to this. For example, sidewall 2
20 may be inclined so as to expand upward and outward, or may be inclined so as to expand downward and outward.

As described above, the embodiments and the modifications of the present invention have been described. However, it is originally intended to appropriately combine the features of the embodiments and the modifications. Further, the embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the embodiments described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1, 1a, 1b, 1c, 1d Cell stack device, 4 first current collecting member, 5 second joining material, 6 second current collecting member, 100 fuel cell, 101 lower end, 102 upper end, 103
Cell assembly, 104 cell assembly, 110 support substrate, 111 gas flow path, 112, 302
Outer surface, 112a first concave portion, 113 first main surface, 114 second main surface, 115 side end surface, 116, 171 lower end surface, 116a C surface, 116b horizontal surface, 117 upper end surface, 12
0 power generation element part, 121 reaction prevention film, 122 dense film, 130 fuel electrode, 131 fuel electrode current collector, 131a second concave part, 131b third concave part, 132 fuel electrode active part, 140
Electrolyte, 150 air electrode, 160 electrical connection, 161 interconnector, 162
Air electrode current collecting film, 170 covering portion, 180 intermediate layer, 200 manifold, 210 bottom wall, 220 side wall, 230 upper wall, 231 insertion hole, 240 flange portion, 300 first joining material, 301 exposed surface, P introduction pipe.

Claims (4)

A fuel cell whose lower end is supported by a manifold made of a material containing chromium,
An outer surface extending in the up-down direction, and a support substrate having a lower end surface connected to a lower end of the outer surface,
A power generation element unit provided on the outer surface and having a fuel electrode, an electrolyte, and an air electrode,
A covering portion that covers at least a part of the lower end surface and is formed of a compound containing chromium,
A fuel cell comprising:   The fuel cell according to claim 1, wherein the lower end surface includes a C plane. The fuel cell according to claim 1, wherein the lower end surface is curved upward or downward. A fuel cell according to any one of claims 1 to 3,
While supporting the lower end of the fuel cell, a manifold made of a material containing chromium,
A joining material for joining the manifold and the fuel cell,
A cell stack device comprising:

Images