JP2003272667A - Fuel battery cell and cell stack as well as fuel battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel battery cell, and a cell stack as well as a fuel battery, capable of making an inner resistance in an electrode small and making an effective use of gas passing through a gas through-hole in an inner electrode. <P>SOLUTION: A fuel side electrode 21 with a gas through-hole formed in an axis length direction, a solid electrolyte 23 formed on the surface of that inner electrode 21, and an oxygen side electrode 25 formed on the surface of the solid electrolyte 23 are provided, and further, a plurality of conductive columnar bodies 29 for coupling opposing inner faces of the inner electrode are fitted inside the gas through-hole 28 of the inner electrode. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell, a cell stack and a fuel cell, and more particularly to a fuel cell, a cell stack and a fuel cell having good power generation performance.

[0002]

2. Description of the Related Art In recent years, various fuel cells in which a stack of fuel cells are housed in a container have been proposed as next-generation energy.

FIG. 6 shows a cell stack of a conventional solid oxide fuel cell. In this cell stack, a plurality of fuel cells 1 (1a, 1b) are assembled and one fuel cell 1a and the other fuel cell 1a are assembled. The fuel-side electrode 7 of one fuel cell 1a and the oxygen-side electrode 11 of the other fuel cell 1b are electrically connected by interposing a current collecting member 5 made of a metal felt between the fuel cell 1b and the other fuel cell 1b. Was configured.

The fuel cell 1 (1a, 1b) is constructed by sequentially providing a solid electrolyte 9 and an oxygen-side electrode 11 made of a conductive ceramic on an outer peripheral surface of a fuel-side electrode 7 made of a cylindrical metal. , Solid electrolyte 9, oxygen side electrode 11
The surface of the fuel-side electrode 7 exposed from the
An interconnector 13 is provided so as not to be connected to.

The interconnector 13 includes a fuel gas (hydrogen) flowing inside the fuel-side electrode 7 and an oxygen-side electrode 11.
In order to surely block the oxygen-containing gas (air) flowing outside the chamber, a dense conductive ceramic is used which is unlikely to deteriorate even when exposed to the fuel gas and the oxygen-containing gas.

The electric connection between the one fuel cell 1a and the other fuel cell 1b is made by connecting the fuel side electrode 7 of the one fuel electrode 1a to the interconnector 13 provided on the fuel side electrode 7 and collecting electricity. The other fuel cell 1 through the member 5
It was performed by connecting to the oxygen side electrode 11 of b.

A fuel cell is constructed by accommodating the above cell stack in an accommodating container. Fuel (hydrogen) is caused to flow inside the fuel-side electrode 7 and oxygen-containing gas (air) is caused to flow at the oxygen-side electrode 11 to produce a fuel cell of 600- Power is generated at 1000 ° C.

The current generated by the fuel cell 1 flows from the oxygen side electrode 11 of the other fuel cell 1b to the fuel side electrode 7 of the one fuel cell 1a.

[0009]

However, in the fuel cell 1 described above, one gas passage hole 15 is formed inside the cylindrical fuel side electrode 7, and the fuel gas flows through the inside. , The fuel gas in the gas passage hole 15 is
In terms of fluid dynamics, the amount of flow in the vicinity of the inner wall surface of the fuel-side electrode 7 is smaller than that in the central portion of the gas passage hole 15, the amount of fuel gas supplied to the solid electrolyte 9 is still low, and it is said that fuel gas is not effectively used. There was a problem.

Further, in the above-mentioned fuel cell 1, since the generated current flows along the electrode surface formed in the circumferential direction, there is a problem that the path of the current becomes long and the internal resistance becomes large.

In order to reduce such internal resistance, conventionally, a solid electrolyte and an electrode are sequentially laminated on a plate-shaped electrode base, and a plurality of through holes (gas passage holes) are formed on the electrode base to generate power. An electric current flows between adjacent gas passage holes of the electrode substrate to shorten the current path and reduce the internal resistance (Japanese Patent Application Laid-Open No. 5-36417).

However, even in such a fuel cell, as described above, the gas introduced into each gas passage hole easily flows in the central portion of the gas passage hole, but the supply to the vicinity of the inner wall surface of the electrode substrate is small. Therefore, there is a problem that the gas supply efficiency to the solid electrolyte is low and the gas utilization efficiency is low.

Further, since the distance between the gas passage holes is large,
Furthermore, since the partition between the gas passage holes is formed continuously in the gas flow direction, the amount of supply to the solid electrolyte between adjacent gas passage holes is small, and for example, hydrogen is passed through the electrode substrate to generate electricity. In this case, it is difficult for the electrode substrate to be reduced,
There is a problem that the electric conductivity of the electrode substrate is low and the power generation performance is low.

It is an object of the present invention to provide a fuel cell, a cell stack, and a fuel cell which can reduce the internal resistance of the electrode and can effectively utilize the gas passing through the gas passage hole inside the inner electrode.

[0015]

The fuel cell of the present invention comprises an inner electrode having gas passage holes formed in the axial direction, a solid electrolyte formed on the inner electrode surface, and a solid electrolyte surface formed on the solid electrolyte surface. And a plurality of conductive columnar bodies that connect opposing inner surfaces of the inner electrode to each other in the gas passage hole of the inner electrode.

In such a fuel cell, since a plurality of conductive columnar bodies for connecting opposing inner surfaces are provided in the gas passage hole of the inner electrode, the gas flows through the gas passage hole, but the conductive columnar body is formed. It is possible to increase the supply amount to the inner electrode surface which is diffused by the body and forms the gas passage hole, and thereby the supply amount from the inner electrode to the solid electrolyte surface can be increased, and the gas passing through the gas passage hole can be effectively used, Power generation performance can be improved. Further, since the gas is diffused by the conductive columnar body, and since the conductive columnar bodies are scattered in the axial direction of the gas passage hole, when fuel gas such as hydrogen is supplied to the inner electrode side to generate electricity, Since the inner electrode can be sufficiently reduced and the partition between the gas passage holes is not continuously formed in the gas flow direction as in the conventional case, the fuel gas can be sufficiently supplied to this portion. , Power generation performance can be improved.

Further, the generated current flows through a plurality of conductive columnar bodies which connect the inner surfaces of the inner electrode which face each other, whereby the current path can be shortened with a simple structure, the internal resistance can be reduced, and the voltage gradient can be reduced. can do.

Further, the fuel cell of the present invention is characterized in that the interconnector is formed on the surface of the inner electrode on which the solid electrolyte and the outer electrode are not formed.
In such a fuel cell, current can be taken out from the interconnector through the plurality of conductive columnar bodies that connect the inner surfaces of the inner electrode facing each other, and the current path can be shortened to reduce the internal resistance.

In the fuel cell of the present invention, it is desirable that the inner electrode be flat. When the inner electrode has a flat shape, the circumferential distance of the inner electrode is long, and therefore the current path between the facing portions of the inner electrode tends to be long, and the present invention can be preferably used.

Since the inner electrode as the support has a flat shape, the cell itself also has a flat shape, whereby the cell stack volume required to obtain a predetermined generated current can be reduced,
The fuel cell can be made compact.

Here, it is preferable that the gas passage hole of the inner electrode is flat and the conductive columnar body connects the inner surfaces of the inner electrodes facing each other in the minor axis direction. The gas flowing through the flat gas passage hole does not easily pass in the major axis direction, but the conductive columnar body can sufficiently diffuse the gas in the major axis direction of the gas passage hole, and the gas passing through the gas passage hole can be effectively used. .

Further, in the fuel cell of the present invention, it is desirable that the conductive columnar bodies are provided in a zigzag pattern in the axial direction of the inner electrode. Thereby, the gas passing through the gas passage hole can be sufficiently diffused, and the gas can be effectively used.

The cell stack of the present invention comprises a plurality of the above fuel cells. Further, the fuel cell of the present invention has the above cell stack housed in a housing container. In such a fuel cell, the fuel cell can reduce the internal resistance of the inner electrode and can effectively use the gas passing through the gas passage hole of the inner electrode, so that the power generation amount can be increased and the gas consumption can be increased. The amount can be reduced.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view of a fuel battery cell according to the present invention, which has a flat shape. This fuel cell has a dense solid electrolyte 23 and an oxygen side made of porous conductive ceramics on the outer surface of one side of the fuel-side electrode 21 (inner electrode) whose main component is a flat porous metal. The electrode 25 (outer electrode) is sequentially laminated, and the interconnector 27 is laminated on the outer surface of the other side of the fuel side electrode 21. The fuel side electrode 21 serves as a support.

The fuel-side electrode 21 is elongated and has one fuel gas passage 28 formed therein in the axial direction. The fuel gas passage 28 is flat. The fuel-side electrode 21 does not have to be flat, and may have a cylindrical shape, an elliptic cylindrical shape, or a rectangular cylindrical shape. However, when the fuel-side electrode 21 has a flat shape, the area for generating electricity is increased. be able to.

The fuel side electrode 21 is made of Ni, Co, Ti, R
u is mainly composed of any one of metals or metal oxides of u, or alloys or alloy oxides thereof, and in addition to these, the solid electrolyte 23 is improved in bonding strength with the solid electrolyte 23 on the outer surface. It is desirable to contain a solid electrolyte material in order to approximate the coefficient of thermal expansion of. As the metal or metal oxide, Ni or Ni is used from the viewpoint of cost.
O is desirable.

The solid electrolyte 23 provided on the outer surface of the fuel-side electrode 21 is made of a dense ceramic containing partially stabilized or stabilized ZrO ₂ containing 3 to 15 mol% Y and a rare earth element. . Between the fuel side electrode 21 and the solid electrolyte 23, in order to improve the joint strength with the fuel side electrode 21, a joint layer composed of a dense layer may be interposed. The thickness of the solid electrolyte 23 is preferably 10 to 100 μm from the viewpoint of preventing gas permeation.

The oxygen side electrode 25 is made of at least one kind of porous conductive ceramics of LaMnO ₃ type material, LaFeO ₃ type material and LaCoO ₃ type material. The oxygen-side electrode 25 has a high electric conductivity at a relatively low temperature of about 600 to 1000 ° C., and thus LaFeO
₃ series material is desirable. The thickness of the oxygen-side electrode 25 is preferably 30 to 200 μm from the viewpoint of current collection.

Then, on a part of the outer surface of the fuel side electrode 21,
It has a portion where the solid electrolyte 23 and the oxygen side electrode 25 are not formed in the axial direction, and an interconnector 27 made of conductive ceramics is formed on the exposed outer surface of the fuel side electrode 21. .

The thickness of the interconnector 27 is preferably 30 to 200 μm from the viewpoint of compactness and electric resistance. The interconnector 27 is made of conductive ceramics of LaCrO ₃ system material. The interconnector 27 is a fuel gas inside and outside the fuel side electrode 21,
It is made dense to prevent leakage of the oxygen-containing gas, and the inner and outer surfaces of the interconnector 27 are in contact with the fuel gas and the oxygen-containing gas, and thus have reduction resistance and oxidation resistance.

A bonding layer may be interposed between the end surface of the interconnector 27 and the end surface of the solid electrolyte 23 in order to improve the sealing property.

In the fuel cell of the present invention, as shown in FIG.
And as shown in FIG. 2, the gas passage hole 2 of the fuel side electrode 21
A plurality of conductive columnar bodies 29 that connect the inner surfaces of the fuel-side electrode 21 that face each other are provided in the inside 8. These conductive columnar bodies 29 are made of the same material as the fuel side electrode 21 and are porous.

That is, the fuel-side electrode 21 has a cross-sectional shape composed of arc-shaped portions 21a provided at both ends in the width direction and a pair of flat portions 21b connecting these arc-shaped portions 21a. The parts 21b are flat and formed substantially parallel to each other. Therefore, the fuel-side electrode 21 has one gas passage hole 28 whose cross-sectional shape is similar to the outer shape of the fuel-side electrode 21.

A plurality of the above-mentioned conductive columns 29 are arranged so as to connect the pair of flat portions 21b, and the inner surfaces of the fuel-side electrodes 21 facing each other in the minor axis direction are connected to each other. Here, the space between the flat portions 21b has a short diameter, and the space between the arc-shaped portions 21a has a long diameter. The conductive columnar bodies 29 are arranged in a zigzag pattern in the axial direction of the fuel electrode 21.

The conductive columnar body 29 need not be formed of the same material as the fuel side electrode 21 as long as it has conductivity, and need not be porous.

A method of manufacturing the above fuel cell will be described. First, for example, a fuel-side electrode material obtained by mixing NiO powder, ZrO ₂ (YSZ) powder containing Y, an organic binder, and a solvent is formed into a sheet shape, and as shown in FIG. A plurality of columnar molded bodies 32 made of the same material as the sheet-shaped molded body 31 are formed on the molded body 31.
Are arranged, the sheet-shaped molded body 31 is folded back, the end faces are connected to each other to produce a fuel-side molded body, and this is dried.

Next, for example, a sheet-shaped molded body is produced using a solid electrolyte material in which YSZ powder, an organic binder and a solvent are mixed, and this sheet-shaped molded body is formed on the fuel-side electrode molded body. Then, it is wound so that both ends thereof are separated by a predetermined distance and dried.

Thereafter, for example, a LaCrO ₃ system material,
An organic binder and a solvent are mixed to prepare a sheet-shaped molded article using an interconnector material, and the sheet-shaped molded article is laminated on the exposed outer surface of the fuel-side electrode molded article,
A laminated molded body is produced in which a sheet-shaped molded body of a solid electrolyte and a sheet-shaped molded body of an interconnector are laminated on the outer surface of a fuel-side electrode molded body.

Next, the laminated molded body is subjected to binder removal treatment and co-fired at 1300 to 1600 ° C. in an oxygen-containing atmosphere,
This laminated body is dipped in a paste containing, for example, a LaFeO ₃ material and a solvent, and an oxygen-side electrode molded body is formed on the surface of the solid electrolyte by dipping.
The fuel cell of the present invention can be produced by baking at 1300 ° C. The fuel-side electrode 21 and the conductive columnar body 29 containing NiO as a main component are reduced before power generation or during power generation.

In the fuel cell constructed as described above, power is generated by supplying a fuel gas consisting of, for example, hydrogen into the fuel gas passage 28 and supplying air, for example, to the oxygen side electrode 25 side. become.

In the fuel cell of the present invention, the fuel gas passing through the gas passage hole 28 is diffused by the conductive columnar body 29 to increase the supply amount to the inner surface side of the fuel side electrode 21 and the power generation characteristic. Since the flat portions 21b facing each other are connected by the conductive columnar body 29, a current flows to the interconnector 27 through the conductive columnar body 29, so that the current path can be shortened and the internal resistance can be reduced. And the cell strength can be improved. Further, since the conductive columns 29 are scattered in the gas flow direction, the fuel-side electrode 2
1. The conductive columnar body 29 can be sufficiently reduced, and since the joint portion between the conductive columnar body 29 and the fuel electrode 21 is small, the fuel gas can be sufficiently supplied to the fuel side electrode 21 and the power generation performance can be improved. Can be improved.

In the above embodiment, the interconnector 27 is formed on the fuel side electrode 21, but the solid electrolyte and the oxygen side electrode may be formed on the entire circumferential surface without forming the interconnector. Further, in the above embodiment, one fuel gas passage hole 28
Although the conductive columnar body 29 is formed in the above, the conductive columnar body may be provided in a fuel cell having a plurality of fuel gas passage holes. Further, in the above embodiment, the fuel side electrode 21 is the inner electrode, but the oxygen side electrode may be the inner electrode.

As shown in FIG. 4, the cell stack of the present invention is composed of a plurality of the above-mentioned plurality of fuel battery cells 33, and one fuel battery cell 33 and the other fuel battery cell 33.
And a current collecting member 45 made of a metal felt and / or a metal plate, and the fuel side electrode 21 of one fuel cell 33 is connected to the interconnector 27 provided on the fuel side electrode 21 It is configured to be electrically connected to the oxygen-side electrode 25 of the other fuel cell 33 via the member 45. The current collecting member 45 is preferably made of at least one of Pt, Ag, Ni-based alloy, and Fe—Cr steel alloy from the viewpoint of heat resistance, oxidation resistance, and electric conductivity.

The fuel cell of the present invention is constructed by accommodating the cell stack 47 of FIG. 4 in a container. FIG. 5 shows a fuel cell of the present invention, and reference numeral 51 denotes a storage container having a heat insulating structure. Inside the storage container 51, a cell stack 4 in which a plurality of fuel cells 33 are assembled
7 and the combustion chamber 53 adjacent to the upper side of the cell stack 47.
And an oxygen-containing gas supply pipe 55 that passes through the combustion chamber 53
And a heat exchange section 57 provided above the combustion chamber 53.

The storage container 51 includes a frame 51a made of a heat-resistant metal, and a heat insulating material 5 provided on the inner surface of the frame 51a.
1b and.

As shown in FIG. 4, in the cell stack 47, a plurality of fuel cells 33 are arranged in three rows, and the electrodes of the outermost fuel cells 33 in the two rows adjacent to each other are made of conductive members 59. The plurality of fuel cells 33 arranged in three rows are electrically connected in series.

The upper and lower ends of the plurality of fuel cells 33 are supported and fixed to support members 65 and 67 as shown in FIG.
Thereby, the fuel cell 33 is supported and fixed. The support members 65 and 67 also serve as a partition that partitions the storage container 51 in the vertical direction, and the portion of the fuel cell 33 between the support members 65 and 67 generates power, and the support members 65 and 67 are separated from each other. It is used as the power generation room 69.

Below the cell stack 47, a fuel gas supply pipe 71 for supplying fuel gas to the cell stack 47.
The fuel gas supply pipe 71 is provided with a branch pipe 72 for supplying the fuel gas to the fuel gas passage 28 of the fuel cell 33.

Below the fuel gas supply pipe 71, a burner gas supply pipe 7 for directly heating the fuel cell unit.
3 are arranged, the burner gas supply pipe 73 is provided with a plurality of burner branch pipes 75 for combustion below the power generation chamber 69, and the tip ends of these burner branch pipes 75 are supported by the support member 67. It is fixed to. The power generation chamber 69 is provided with an ignition source for igniting the combustion gas ejected from the burner branch pipe 75 at startup. Also in the combustion chamber 53, an ignition source for igniting at startup is provided.

The oxygen-containing gas supply pipe 55 passing through the combustion chamber 53 is passed through the supporting member 65, and the tip portion thereof is in the power generating chamber 69.
Is located below the fuel cell 33 and between the fuel cells 33. The surplus oxygen-containing gas that has not been used in power generation is configured to be ejected into the combustion chamber 53 from the surplus gas ejection holes 77 provided in the support member 65.

The heat exchanging section 57 is composed of a heat exchanger 57a and an oxygen-containing gas storage chamber 57b provided so as to face the cell stack 47 via the combustion chamber 53.

The heat exchanger 57a has a plate fin type structure in which flat plates and corrugated plates are alternately laminated.

The combustion gas generated in the combustion chamber 53 is as shown in FIG.
Is introduced from the lower side surface of the heat exchanger 57a and is discharged above the heat exchanger 57a, while
The oxygen-containing gas is introduced from the upper side surface of the heat exchanger 57a through the pipe 83, as shown by the broken line in FIG. 5, guided to the lower side of the heat exchanger 57a, and introduced into the oxygen-containing gas storage chamber 57b.

The oxygen-containing gas storage chamber 57b has a heat exchanger 5
It is provided on the end surface of 7a on the side where the oxygen-containing gas is introduced, that is, the end surface on the cell stack side, and the oxygen-containing gas that has passed through each passage of the corrugated plate is temporarily stored. A plurality of oxygen-containing gas supply pipes 55 communicate with the oxygen-containing gas storage chamber 57b.

Between the side surface of the oxygen-containing gas storage chamber 57b and the heat insulating material 51b, that is, around the oxygen-containing gas storage chamber 57b, a combustion gas inlet 85 for introducing the combustion gas in the combustion chamber 53 into the heat exchanger 57a. It is said that. The combustion gas is led out to the passage of the corrugated plate of the heat exchanger 57a through the combustion gas inlet 85.

In the fuel cell configured as described above, an oxygen-containing gas (for example, air) from the outside is introduced into the heat exchanger 57a through the pipe 83 and into the oxygen-containing gas storage chamber 57b to supply the oxygen-containing gas. The fuel gas (for example, hydrogen) is ejected between the cells of the power generation chamber 69 via the pipe 55 and
Is supplied into the fuel gas passage 28 of the fuel cell 33 through the fuel gas supply pipe 71, and the cell 33 in the power generation chamber 69 is
To generate electricity.

Excess fuel gas that has not been used for power generation is jetted into the combustion chamber 53 from the upper end of the fuel gas passage 28, and excess oxygen-containing gas that has not been used for power generation is output from the surplus gas jet holes 77 to the combustion chamber. Injected into 53, the excess fuel gas and the excess oxygen-containing gas are reacted and burned to generate combustion gas, and this combustion gas is led out to the heat exchanger 57a via the combustion gas inlet 85, It is discharged from the upper end of the exchanger 57a.

In the fuel cell of the present invention, the surplus fuel gas and oxygen-containing gas that have not contributed to power generation are introduced into the combustion chamber 53, and react and burn in the combustion chamber 53. Of the oxygen-containing gas is introduced into the heat exchanger 57a, and the heat-exchanger 57a exchanges heat between the combustion gas and the oxygen-containing gas to preheat the oxygen-containing gas, so that the fuel cell 33 is heated. Then, the starting time until the power is substantially generated can be shortened significantly.

Further, in the present invention, since the combustion chamber 53, the oxygen-containing gas storage chamber 57b, and the heat exchanger 57a are formed adjacent to each other on the upper portion of the cell stack 47, the high temperature combustion gas burned in the combustion chamber 53 is , Can be directly introduced into the heat exchanger 57a without using pipes, etc., and the preheating efficiency of the oxygen-containing gas can be increased with a simple structure.

Further, since the combustion gas and the oxygen-containing gas can be heat-exchanged in the storage container 51, it is not necessary to separately provide a burner for preheating the oxygen-containing gas, the size can be reduced, and the combustion gas can be effectively used. Available.

Further, since the heat exchanger 57a is provided with the oxygen-containing gas storage chamber 57b, the heat exchanger 57a and the oxygen-containing gas supply pipe 55 can be connected via the oxygen-containing gas storage chamber 57b. The oxygen-containing gas from the heat exchanger 57a can be reliably supplied into the power generation chamber 69.

Since the burner branch pipe 75 for directly heating the fuel cell 33 is provided, the gas ejected from the tip of the burner branch pipe 75 at the time of start-up is burned to directly heat the fuel cell 33. As a result, the fuel cell 33 can be heated directly to a temperature at which power is generated, and the startup time can be further shortened.

The present invention is not limited to the above-described embodiment, but various modifications can be made without departing from the spirit of the invention.

[0064]

In the fuel cell of the present invention, since a plurality of conductive columnar bodies for connecting the inner surfaces facing each other are provided in the gas passage holes of the inner electrodes, the generated current is generated by the inner surface facing the inner electrodes. It flows through a plurality of conductive columns that connect each other, and this makes it possible to shorten the current path with a simple structure and reduce the voltage gradient, and the gas flows through the gas passage holes but is diffused by the conductive columns. Therefore, the gas can be sufficiently supplied to the inner electrode, and the gas passing through the gas passage hole can be effectively used.

[Brief description of drawings]

FIG. 1 is a perspective view of a fuel battery cell of the present invention.

2 is a cross-sectional perspective view of FIG.

FIG. 3 is a perspective view for explaining a method of manufacturing a fuel side electrode.

FIG. 4 is a cross-sectional view showing a cell stack of the present invention.

FIG. 5 is an explanatory diagram showing a fuel cell of the present invention.

FIG. 6 is a cross-sectional view showing a conventional cell stack.

[Explanation of symbols]

21 ... Fuel side electrode (inner electrode) 23 ... Solid electrolyte 25 ... Oxygen side electrode (outer electrode) 27 ... Interconnector 28 ... Gas passage hole 29 ... Conductive columnar body 33 ... Fuel cell 51 ... Storage container

Claims (7)

[Claims] 1. An inner electrode having a gas passage hole formed in the axial direction, a solid electrolyte formed on a surface of the inner electrode, and an outer electrode formed on a surface of the solid electrolyte. A fuel battery cell, characterized in that a plurality of conductive columnar bodies are provided in the gas passage holes of the electrodes to connect the inner surfaces of the inner electrode facing each other. 2. The fuel cell according to claim 1, wherein an interconnector is formed on the surface of the inner electrode on which the solid electrolyte and the outer electrode are not formed. 3. The fuel cell according to claim 1, wherein the inner electrode has a flat shape. 4. The gas passage hole of the inner electrode is flat, and the conductive columnar body connects the inner surfaces of the inner electrode opposed to each other in the minor axis direction. The fuel cell according to any one of the above. 5. The conductive columnar body is provided in a zigzag pattern in the axial direction of the inner electrode.
5. The fuel cell according to any one of 4 to 4. 6. A cell stack comprising a plurality of the fuel cells according to any one of claims 1 to 5 assembled together. 7. A fuel cell comprising a plurality of fuel battery cells according to claim 1 housed in a housing container.