JPH11185793A - Manifold structure and stack structure of solid electrolyte fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolyte type fuel cell having a plurality of gas passages which can prevent degradation of the air-tightness at the boundary between a manifold member and a unit cell in the course of long time operation and can preclude drop of the power generating efficiency and electromotive force. SOLUTION: A unit cell 1 is furnished with a plurality of gas passages 5 for a gas for power generation in such a way as stretching between one end face 1a of the unit cell and the other end face 1b. A manifold structure is furnished to perform gas introduction and exhaustion to/from the gas passages. Beside the unit cell 1, the manifold structure comprises a manifold member 41 attached to the end face 1a of the unit cell and a gas flow pipe 42 of ceramics which is attached to the manifold member 41. The manifold member is furnished with gas flowing holes 42c in the pipe 42 and a gas distribution space 41c in communication with the gas passages 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a manifold structure and a stack structure of a unit cell of a solid oxide fuel cell.

[0002]

2. Description of the Related Art Solid oxide fuel cells (SOFCs)
It is roughly classified into a flat plate type and a cylindrical type (Comprehensive Energy Engineering 1)
3-2, 1990). The electromotive force of a SOFC cell is
Approximately 1 V in open circuit, and current density is at most several hundred mA /
Since it is about cm ² , in actual use, it is important that cells having a large power generation area can be easily connected in series and in parallel. From this viewpoint, the structure of the unit cell and its stack (collective cell) must be examined.

[0003] In particular, in a stack structure of a solid oxide fuel cell, it is required to maintain airtightness between the oxidizing gas and the fuel gas at the operating temperature of the power generator. For example,
In a so-called Westinghouse type solid electrolyte fuel cell, a cylindrical air electrode is used as a base, and a solid electrolyte film and a fuel electrode film are formed thereon. The present applicant also discloses a flat unit cell having a structure in which a laminated sintered body including an air electrode and an interconnector is used as an air electrode / interconnector base, and a solid electrolyte film and a fuel electrode film are formed thereon. It has been disclosed (JP-A-5-166518). In these stack structures, a so-called sealless structure is adopted. That is, an oxidizing gas supply pipe is inserted into each of the oxidizing gas passages formed in each cell, and the oxidizing gas is supplied from the oxidizing gas supply pipe to the inside of the cell. The exhaust oxidizing gas discharged from each oxidizing gas passage of the unit cell is guided to flow to the combustion chamber, and is reacted with the exhaust fuel gas in the combustion chamber.

However, according to this method, for example,
As disclosed in Japanese Patent Publication No. 166518, it is necessary to provide, for example, three or more oxidizing gas passages in a single cell, and to insert a gas supply pipe into each oxidizing gas passage. Therefore, a large number of gas supply pipes are required, and it is necessary to separately insert each gas supply pipe into each oxidizing gas passage of each unit cell.

On the other hand, several methods have been proposed for stacking a plurality of cells having a plurality of oxidizing gas passages to form a so-called stack structure (for example, Japanese Patent Application Laid-Open No. 7-22 / 1995).
No. 6220). In this stack structure, a rectangular cell stack is formed. In this stack, each cell is connected in series. Thereafter, the current collectors are brought into contact with the uppermost end and the lowermost end of the stack, respectively, and the stack and the current collectors are accommodated and fixed in a metal outer shell. In this case, a heat insulating material layer is provided inside the outer shell. Then, the oxidizing gas is supplied to the oxidizing gas passage provided in the unit cell, and at the same time, the fuel gas is caused to flow inside the heat insulating layer, and the fuel gas is brought into contact with the fuel electrode outside each unit cell. Power generation is performed in a single cell. The electric power of the plurality of unit cells connected in series is extracted from the pair of current collectors.

[0006] Air manifolds are respectively installed on two opposing surfaces of the four circumferences of the unit cell stack,
Air is flowing from one manifold to the other. In addition, fuel manifolds are provided on the remaining two opposing surfaces of the four circumferences of the unit cell stack, and fuel gas flows from one manifold to the other manifold.

[0007]

However, the following problems remain in the manifold structure of the unit cell stack as described above. For example, in the manifold structure disclosed in Japanese Unexamined Patent Publication No. 7-226220, an oxidizing gas manifold member is fixed to two opposing surfaces of a stack of a plurality of unit cells, respectively, and the stack is connected to each manifold member. Is rigidly sealed by a gasket or a sealing material to prevent mixing of the oxidizing gas and the fuel gas. In such a structure, for the manifold member,
A number of cells are rigidly fixed, and the space between the manifold member and each cell is hermetically sealed.

However, when power is actually generated, the airtightness at the boundary between the manifold member and the stack tends to decrease, and this tendency has become remarkable as the operation time increases. When the airtightness is reduced, it causes a reduction in power generation efficiency and electromotive force.

An object of the present invention is to prevent a decrease in airtightness at a boundary between a manifold member and a unit cell even when the cell is operated for a long time, particularly in a solid oxide fuel cell having a plurality of gas passages, The purpose is to prevent a decrease in power generation efficiency and electromotive force.

[0010]

A manifold structure of a solid oxide fuel cell according to the present invention is a single cell of a solid oxide fuel cell, and includes at least an air electrode, a fuel electrode, and a solid electrolyte. For a unit cell in which a plurality of gas passages for flowing one gas for power generation are provided so as to extend between one end surface and the other end surface of the unit cell, one gas for power generation is provided for each gas passage. A manifold structure for performing introduction or exhaust of the cell, the manifold structure includes a cell, a manifold member attached to one end surface side of the cell, and a ceramic member attached to the manifold member. A gas distribution pipe, and the manifold member is provided with a gas distribution space communicating with gas distribution holes of the gas distribution pipe and a plurality of rows of gas passages. It is characterized in that is.

Further, the present invention provides a stack structure having the above-mentioned manifold structure, wherein a plurality of cells are provided,
It is characterized by comprising a plurality of manifold members attached to the unit cells and a container for accommodating the unit cells.

The present inventor has studied the cause of the decrease in airtightness at the boundary between the manifold member and the stack, and has obtained the following knowledge. That is, the temperature in the container accommodating the stack reaches 1000 ° C. or more at the time of power generation, but at this time, the temperature of each cell constituting the stack is not necessarily uniform. The cells at the top and bottom of the stack have relatively low gas temperatures and tend to have low power generation efficiency. However, in the unit cell at the center of the stack, especially in the oxidizing gas passage near the center of the unit cell, exhaust heat is concentrated, and the temperature of the unit cell increases, and the temperature increase further increases the activity of the unit cell. The temperature of the central portion of the stack tends to rise. The longer the power generation time, the stronger this tendency.

On the other hand, the cells, the metal manifold member, and the sealant interposed therebetween have different coefficients of thermal expansion. Then, during operation, since the degree of thermal expansion differs between each cell constituting the stack and the manifold member, stress concentrates near the boundary between the manifold member and the cell, particularly around the sealing material. At this time, especially in the unit cell located near the center of the stack, the thermal expansion difference between the unit cell and the manifold member is large,
On the other hand, in the unit cells at the periphery of the stack, the difference in thermal expansion between the unit cells and the manifold member is small. It is considered that due to this difference in thermal expansion, a thermal stress that causes a positional shift acts on the sealing material between the manifold member and the unit cell.

On the other hand, the present inventor prepared a separate manifold member for each cell, attached the manifold member to one end face of the cell, and connected the gas flow tube made of ceramic to the manifold. It has been conceived to provide a gas distribution space which is attached to a member, and which is provided in the manifold member so as to communicate with a gas flow hole of a gas flow pipe and a plurality of rows of gas passages.

Thus, gas can be supplied from a single manifold member to a plurality of gas passages of a unit cell. In addition, since the area of the sealing portion between each unit cell and the corresponding manifold member is small, the sum of thermal stresses caused by the temperature difference in each part of the stack is concentrated on some unit cells. There is no. That is, the strain concentrated on the boundary between each cell and each manifold member is small.

Moreover, even when the degree of expansion and contraction of the cells constituting the stack is different, the cells can move relative to each other. At the same time, each gas supply pipe also changes direction and rotates in accordance with the minute position movement of each cell, and there is room for absorbing the relative position movement of each cell.

In the present invention, the manifold structure is
It means a structure for supplying a power generation gas to each gas passage of a unit cell, or a structure for discharging a depleted power generation gas from each gas passage of a unit cell. Accordingly, the gas flow pipe becomes a gas supply pipe or a gas discharge pipe.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS When an oxidizing gas is used as one power generation gas, a fuel gas is used as the other power generation gas, and when an oxidizing gas is used as the other power generation gas, one of the power generation gases is used. Fuel gas is used as power generation gas.

The materials of the gas flow pipe and the manifold member are as follows:
It must have heat resistance, durability against oxidizing gas and fuel gas. As such a material, alumina, alumina-magnesia spinel, and zirconia are preferable.

In the present invention, the manifold member further includes a protruding wall portion protruding toward one end surface of the cell, and the end of the cell is inserted inside the protruding wall portion. Preferably, a unit cell fixing space for fixing is formed, and the unit cell fixing space communicates with the gas distribution space. At this time, if the protruding wall portion is brought into close contact with at least a pair of main surfaces of the unit cell, the airtightness of the manifold structure is less likely to be broken even with respect to stress acting in the main surface direction of the unit cell. More preferred. In this case, the airtightness of the sealing portion at the boundary between the manifold member and the unit cell is further favorably maintained by making the protruding wall portion adhere to the pair of side surfaces of the unit cell.

These embodiments will be described in more detail with reference to FIGS.

FIG. 1 is a cross-sectional view of a unit cell 1 used in one embodiment of the present invention. FIG. 4 is a longitudinal sectional view showing a stack structure 8 using a stack 36 in which, for example, three unit cells of FIG. 1 are connected in series, and FIG. 5 is a transverse sectional view of the stack structure 8 of FIG. . 2A to 2C show the manifold member 41, and FIG. 3 is a plan view for explaining a connection state between each unit cell 1 and each manifold member 41.

First, the entire stack structure 8 will be described, and then details of the manifold structure will be described.

Support 2 of unit cell 1 (1A, 1B, 1C)
Is composed of an air electrode plate 3 and a separator 4. The planar shape of the separator 4 is a rectangle. A pair of elongated side walls 4a are formed on the edge of the flat body of the separator 4 in the cross-sectional direction.
Are formed. Each of the side walls 4a has a quadrangular prism shape, and extends from one end in the longitudinal direction of the separator 4 to the other end.

Between the pair of side walls 4a, there are provided, for example, three rows of partition walls 4b in the shape of a quadrangular prism. The partition walls 4b extend parallel to each other from one end of the separator 4 in the longitudinal direction to the other end. Parallel grooves are formed between the side walls 4a and the partition walls 4b, for example, in total of four rows.

The plane shape of the air electrode plate 3 is the same as the plane shape of the separator 4. A pair of elongated side walls 3a are formed at the edges of the flat plate body of the air electrode plate 3 in the cross-sectional direction, and a rectangular column-shaped partition wall 3b is formed between the pair of side walls 3a.
For example, three rows are provided. Between the side wall 3a and the partition wall 3b, parallel grooves are formed, for example, in a total of four rows.
Each side wall 4a of the separator 4 is joined to each side wall 3a of the air electrode 3, and each partition 4b of the separator 4
It is joined to each partition 3b of the air electrode plate 3. As a result, for example, four rows of oxidizing gas passages 5 are formed between the air electrode plate 3 and the separator 4.

The solid electrolyte membrane 6 has a main surface 3c of the air electrode 3,
The side surface 3d is covered, and further, the upper part of the width direction side surface 4d of the separator 4 is covered. The oxidizing gas passage 5 and the side surface 3d of the air electrode 3 are both surrounded by a separator 4 and a solid electrolyte membrane 6 which are airtight. The fuel electrode film 7 is formed on the solid electrolyte film 6.

Each cell as shown in FIG. 1 is stacked and connected in series to form a stack 36 as shown in FIGS. In the stack 36, for example, three unit cells 1A, 1B, and 1C are stacked.
Each main surface 4c of each separator 4 of each cell 1A, 1B is
Each of the fuel cells 7B of each of the lower unit cells 1B and 1C is connected via a gas-permeable conductive material 17 respectively. Nickel felt and nickel sponge are preferable as the air-permeable conductive material.

In this embodiment, the container 32 is manufactured by combining one current collector 12A and the other current collector 12B. At this time, the container 32 is assembled after the stack 36 is sandwiched between the current collector plates 12A and 12B.

Each of the current collecting plates 12A and 12B is
a, side plate parts 12b and 12d and a protruding part 12c. The protrusion 12c of the current collector 12A and the protrusion 12c of the current collector 12B are aligned as shown in FIG. 5, and the insulating member 13 is sandwiched between the protrusions. Then, the protrusions 12c of the current collector plates 12A and 12B are fastened by a fastening member including, for example, the bolt 33 and the nut 34, and pressure is applied as shown by an arrow A by adjusting the fastening force of the bolt. Thus, the projecting portion 14 of the container 32 is formed.

As a result, the power generation area 38 inside the container 32
Accommodates a stack 36 of unit cells connected in series,
Fixed. In this state, a predetermined pressure is applied to each cell in the direction A in which the cells are stacked. The cell 1A of this stack is made of a permeable conductive material 16
And the cell 1C is connected to the current collector plate 12B through the conductive material 16. A heat insulating material layer 11 is provided outside the current collector plates 12A and 12B.
A and 11B are provided, and outer shells 10A and 10B are provided outside each heat insulating material layer. Each bolt 33 penetrates each outer shell and each heat insulating material layer.

In FIG. 4, in order from the left side, the combustion area 30, the power generation area 38, the preheating chamber 19, and the oxidizing gas chamber 24 of the power generation chamber.
Is provided. The stack shown in FIG. 5 shows the state of the power generation area 38 in FIG. The oxidizing gas chamber 24 and the preheating chamber 19 are separated by an airtight partition 20, and the space between the preheating chamber 19 and the power generation chamber is also separated by an airtight partition 44.

Each oxidizing gas supply pipe 4 corresponds to each cell.
2 are provided. The right end of each supply pipe 42 opens into the oxidizing gas chamber 24, and each supply pipe 42 passes through the partition wall 20, the preheating chamber 19, and the partition wall 44, and is connected to one end face 1 a of each unit cell by the manifold member 41. It is attached to. 44a and 20a are through holes of each partition, respectively.

Next, the manifold structure will be described. FIG.
2A is a front view of the manifold member 41, and FIG.
2B is a plan view showing a state where the supply pipe 42 is attached to the member 41, and FIG. 2C is a longitudinal sectional view thereof. FIG.
FIG. 3 is a plan view showing a state where the manifold member and the unit cell 1 are combined.

As shown in FIG. 4, the manifold member 41 is attached to each end of each unit cell. A pair of projecting wall portions 41a, 4a
1b is provided, and a unit cell fixing space 41d is formed between the protruding wall portions 41a and 41b. Fixed space 4
The fixed space 41e of the supply pipe is provided on the opposite side of 1d, and the fixed space 41d of the cell and the fixed space 41e of the supply pipe are provided.
Communicate with the distribution space 41c.

The end 42a of the supply pipe 42 is fixed to the fixed space 41e.
The end face 42b of the supply pipe 42 faces the rectangular parallelepiped distribution space 41c. On the other hand, cell 1
Is inserted into the fixed space 41d, and the projecting wall portions 41a and 41b are connected to the main surfaces 1e and 1e of the unit cell.
f (see FIGS. 4 and 5).

As shown in FIGS. 3 and 4, the oxidizing gas is supplied from outside the outer shells 10A and 10B to the oxidizing gas chamber 24 through the supply port 26 as shown by the arrow B. And flows through the gas flow holes 42c of the respective supply pipes as shown by the arrow C. Then, the gas flows from the end face 42b of the supply pipe 42 into the distribution space 41c, then enters one opening 5a of each gas passage 5 of the unit cell 1, flows through each gas passage 5, and flows into the other end face of the unit cell 1. As shown by arrow D from the other opening 5b on the 1b side, it is discharged into the combustion region 30, where it reacts with the fuel gas.

The fuel gas is supplied from the outside of the outer shell by an arrow E
And flows through the gap 15 between the cells and between the cells and the container as shown by the arrow F, and flows into the combustion area 30 as shown in FIG.

In the combustion zone 30, the depleted fuel gas is
Reacts with depleted oxidizing gas and burns. This combustion exhaust gas flows through the exhaust gas pipe 25 as shown by arrows G and H, is supplied into the preheating chamber 19, and is discharged from the preheating chamber 19 through the outlet 27 as shown by the arrow I. Due to the waste heat of the combustion exhaust gas, the gas flow holes 4
The oxidizing gas flowing through 2c can be preheated.

In the present embodiment, a structure for urging the supply pipes toward the unit cells is provided at the supply end of each supply pipe 42. That is, a movable sealing device 40 is installed on the partition wall 20 at the supply-side end on the right side of each supply pipe 42, and each supply pipe 42 is separated from the partition wall 20 in a direction perpendicular to the airtight partition wall 20. It is movable while maintaining airtightness with the supply pipe 42. The movable seal device 40 includes an O-ring 22 and a pressing member 21 that presses each O-ring 22 with a predetermined pressure.
A predetermined urging member 23 is attached to the end face of each supply pipe 42, and urges each supply pipe 42 at a constant pressure toward the corresponding unit cell. I have.

As in the present embodiment, it is preferable to adopt a structure in which the preheating chamber 19 is provided and the gas in the supply pipe 42 is preheated. Thus, it is not necessary to provide a preheating chamber separate from the stack structure outside the stack structure 8.

In the present invention, between one end 42a of the gas flow pipe (for example, 42) attached to the manifold member and the other end of the gas flow pipe, a temperature of 700.degree. Is preferably provided. This eliminates the need to provide a thick heat insulator on the outer shell of the stack structure. Also, an O-ring made of silicone rubber can be used for the movable seal portion.

It is particularly preferable that the protruding walls of the manifold member be in close contact with the pair of main surfaces of the unit cell and also in close contact with the pair of side surfaces of the unit cell.
FIG. 6A is a front view showing such a manifold member 43, FIG. 6B is a plan view showing a state in which the supply pipe 42 is attached to the member 43, and FIG. FIG. 4 is a longitudinal sectional view showing a state in which a supply pipe 42 is attached to 43.

As shown in FIG. 4, the manifold member 43 is also attached to each end of each unit cell. Four rows of projecting wall portions 43a, 4
3b, 43f, and 43g are provided, and a single-cell fixed space 43d is formed therebetween. Fixed space 43
A fixed space 43e for the supply pipe is provided on the side opposite to d. The unit cell fixed space 43d and the supply tube fixed space 43e communicate with the distribution space 43c.

One end 42a of the supply pipe 42 is inserted into the fixed space 43e, and the end face 42b of the supply pipe 42
Faces the rectangular parallelepiped distribution space 43c. Cell 1
Is inserted into the fixed space 43d. The opposed protruding wall portions 43a and 43b are in close contact with the main surfaces 1e and 1f (see FIGS. 3, 4, and 5) of the unit cell, and the opposing protruding wall portions 43f and 43g are connected to the unit cell. Side 1c of
And 1d (see FIG. 3).

[0046]

As described above, according to the present invention, in a solid oxide fuel cell having a plurality of gas passages,
Even when the battery is operated for a long time, it is possible to prevent a decrease in airtightness at the boundary between the manifold member and the unit cell, and prevent a decrease in power generation efficiency and electromotive force.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a cell 1 that can be used in one embodiment of the present invention.

2A is a front view of a manifold member 41, FIG. 2B is a plan view showing a state where a supply pipe 42 is attached to the member 41, and FIG. 2C is a longitudinal sectional view thereof.

FIG. 3 is a plan view showing a state where the manifold member and the unit cell 1 are combined.

FIG. 4 shows a stack 3 obtained by stacking the unit cells of FIG.
FIG. 6 is a longitudinal sectional view showing a stack structure 8 in which a container 6 is accommodated in a container.

FIG. 5 is a cross-sectional view schematically showing the stack structure 8 of FIG.

6A is a front view of another manifold member 43, FIG. 6B is a plan view showing a state where a supply pipe 42 is attached to the member 43, and FIG. 6C is a longitudinal sectional view thereof. It is.

[Explanation of symbols]

1, 1A, 1B, 1C single cell, 2 single cell support,
3 air electrode plate, 4 separator, 5 oxidizing gas passage, 6
Solid electrolyte membrane, 7 fuel electrode membrane, 8 stack structure, 1
0A, 10B outer shell, 11A, 11B heat insulating material layer, 12
A One current collector, 12B The other current collector, 13 Insulation member, 14 Projecting part of container, 15 Fuel gas passage, 19
Preheating chamber, 24 oxidizing gas chamber, 30 combustion area, 32 containers, 36 stacks, 38 power generation area of power generation chamber, 40
Movable seal device, 41, 43 Manifold member, 4
1a, 41b, 43a, 43b Projecting wall portions that closely adhere to the main surface of the cell, 41c, 43c Distribution space, 41d, 43
d Cell fixed space, 41e, 43e Gas flow tube fixed space, 42 Oxidizing gas supply tube, 42a One end of oxidizing gas supply tube, 42c Oxidizing gas supply tube gas flow hole, 43f, 43g Single cell pair Protruding wall portions in close contact with the side surfaces of B, C, D flow of oxidizing gas, E, F flow of fuel gas, G, H, I flow of combustion exhaust gas

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshinori Sakaki 20-1 Kitakanyama, Odaka-cho, Midori-ku, Nagoya City, Aichi Prefecture Inside Chubu Electric Power Co., Inc. (72) Inventor Junichi Fujita 3 Nakanoshima, Kita-ku, Osaka-shi, Osaka 3-22, Kansai Electric Power Co., Inc. (72) Inventor Shinji Takeuchi 3-2-2, Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture Within Kansai Electric Power Co., Ltd. (72) Inventor Shinji Kawasaki Sudacho, Mizuho-ku, Nagoya, Aichi Prefecture No. 2 56 Inside Nihon Insulator Co., Ltd. (72) Inventor Kiyoshi Okumura No. 2 56 Inner Nihon Insulator Co., Ltd. (72) Inventor Makoto Murai Suda Town, Mizuho-ku, Nagoya City, Aichi Prefecture No.2 56 Inside Nihon Insulator Co., Ltd.

Claims (8)

[Claims] 1. A unit cell of a solid oxide fuel cell, comprising:
At least an air electrode, a fuel electrode and a solid electrolyte are provided, and a plurality of gas passages for flowing one power generation gas are provided so as to extend between one end face and the other end face of the unit cell. A single cell, a manifold structure for introducing or exhausting the one power generation gas into each of the gas passages, wherein the manifold structure includes the single cell and the one of the single cells A manifold member attached to the end face side, and a ceramic gas flow pipe attached to the manifold member are provided, and the manifold member has a gas flow hole of the gas flow pipe and the plurality of rows. A gas distribution space communicating with the gas passage of (1), wherein the manifold structure of the solid oxide fuel cell is provided. 2. A manifold for a solid oxide fuel cell according to claim 1, wherein said manifold structure is a manifold structure for supplying said one power generation gas to each of said gas passages. Construction. 3. The manifold member has a protruding wall portion protruding toward the one end face of the unit cell, and the end of the unit cell is inserted inside the protruding wall portion. , A cell fixing space for fixing is formed,
3. The manifold structure for a solid oxide fuel cell according to claim 1, wherein the unit cell fixing space communicates with the gas distribution space. 4. In the unit cell, a pair of opposing main surfaces and a pair of opposing side surfaces are formed between the one end surface and the other end surface. 4. The solid electrolyte type according to claim 3, wherein an end of the unit cell is inserted and fixed, and the protruding wall portion is in close contact with at least the pair of main surfaces of the unit cell. 5. Fuel cell manifold structure. 5. The solid oxide fuel cell manifold structure according to claim 4, wherein said projecting wall portion is in close contact with said pair of side surfaces of said unit cell. 6. A gas flow pipe fixing space for inserting and fixing an end of the gas flow pipe in the manifold member, and the gas flow pipe fixing space communicates with the gas distribution space. 6. The method according to claim 1, wherein
A manifold structure for a solid oxide fuel cell according to any one of the preceding claims. 7. A stack structure comprising a manifold structure of the solid oxide fuel cell according to claim 1, wherein the stack structure includes a plurality of the unit cells and a plurality of the unit cells attached to the unit cells. A stack structure of a solid oxide fuel cell, comprising: a manifold member; and a container for accommodating a plurality of the unit cells. 8. A temperature difference of 700 ° C. or more is provided between one end of the gas flow pipe attached to the manifold member and the other end of the gas flow pipe during power generation. The stack structure of a solid oxide fuel cell according to claim 7, wherein: