JP2001006716A - Solid-oxide fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-oxide fuel cell improved in gas-sealing properties. SOLUTION: In this solid-oxide fuel cell, a cell stack 12 (hereinafter referred to as 'stack') made up by layering flat plate-shaped square cells (each made up by forming an air electrode and a fuel electrode on both sides of a solid electrolyte) with interconnectors between is provided in a cylindrical tube 11, and the stack 12 is supplied with air 13 and fuel 14. Opposite partitions 17 axially running between the cylindrical tube 11 and the stack 12 are provided in gas chambers 15, 16 oppositely formed between the cylindrical tube and the stack, thereby bisecting the gas chambers 15, 16 into first chambers 15a, 16a, and second chambers 15b, 16b. and respective seal portions are sealed with sealing material 18a to 18d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolyte fuel cell having improved gas sealing properties.

[0002]

2. Description of the Related Art Conventionally, a solid oxide fuel cell (SOFC:
Solid Oxide Fuel Cells: Hereinafter referred to as "fuel cells". )
Have been proposed. FIG. 5 shows an example of a conventional fuel cell, and FIG. 6 shows a fuel flow state and an air flow state, respectively. In a conventional fuel cell, a cell stack (hereinafter, referred to as a “stack”) 01 is formed by stacking flat-plate square cells (having an air electrode and a fuel electrode formed on both surfaces of a solid electrolyte) via an interconnector. In the cylindrical tube 02,
An air supply chamber 04 for supplying air 03 to an air electrode 01a constituting the stack 01 and a fuel supply chamber 06 for supplying fuel 05 to a fuel electrode 01b are formed, and air and fuel are supplied by a so-called cross-current method. The air supplied to each cell is discharged from the exhaust air chamber 07 facing the air chamber 04 to the exhaust air 08.
And the fuel supplied to the cell discharges fuel exhaust gas 010 from a discharged fuel chamber 09 facing the fuel supply chamber 06. In addition, four gas seals 011a to 011d are provided in each of the internal parts of the cylinder 02 of the cell stack 01 so that fuel and air do not mix.
As the gas seal 011, for example, a molten sealing material such as glass is used.

However, the operating temperature of the fuel cell is high, and there is a difference in thermal expansion between the cell stack 01 and the cylindrical tube 02. There is a problem that stress occurs in the seal 011 portion. That is, there is a difference between the gas temperature and the gas pressure of the gas to be supplied and the gas to be discharged, and since the gas inlets and the gas outlets of the second seal portion 011b and the fourth seal portion 011d are at different gas pressures, Both the difference and the temperature difference are small and the sealing is easy. On the other hand, the first seal portion 011a and the third seal portion 0
In 11c, since the inlet and the outlet of different kinds of gas are in contact with each other, the gas pressure difference and the temperature difference are large, and the seal is easily broken. There is a problem of destroying the battery.

In view of the above problems, an object of the present invention is to provide a solid electrolyte fuel cell having improved gas sealing properties.

[0005]

According to a first aspect of the present invention, there is provided a cell stack including a flat plate type single cell and an interconnector in a cylindrical tube, and air and air in the stack. In a solid oxide fuel cell having a gas chamber for supplying fuel, a gas chamber is provided in a pair of gas chambers facing each other, the partition walls facing each other along the axial direction between the cylindrical tube and the stack. Is characterized by being divided into two.

According to a second aspect of the present invention, in the first aspect, the undivided gas chamber and one of the divided gas chambers adjacent to the gas chamber are used as a gas supply chamber, and the other undivided gas chamber is used as the gas supply chamber. The chamber and the other divided gas chamber adjacent to the gas chamber are gas discharge chambers.

According to a third aspect of the present invention, in the first aspect, a tube having a square cross section is used in place of the cylindrical tube, and a square stack is provided in the square tube. I do.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of a fuel cell. As shown in FIG. 1, in the fuel cell according to the present embodiment, a flat square cell (having an air electrode and a fuel electrode formed on both sides of a solid electrolyte) in a cylindrical tube 11 through an interconnector. Cell stack (hereinafter referred to as “stack”) 1 formed by stacking
In a solid oxide fuel cell that supplies air 13 and fuel 14 into the stack 12, a cylindrical tube is provided in opposed gas chambers 15 and 16 formed between the cylindrical tube and the stack. An opposing partition wall 17 is provided between the stack 11 and the stack 12 along the axial direction, and the gas chambers 15 and 16 are divided into first chambers 15a and 16a and second chambers 15b and 16b. It is formed by sealing with materials 18a to 18d.

In the above configuration, the divided gas chambers 15,
16, the first gas chambers 15a, 15 facing each other in line
The first gas chamber 15 supplies the air 13 while supplying the air 13 to the second gas chambers 15b and 16b which are opposed to each other in a line symmetric manner at the partition 17 portion.
a, gas chamber 22 which does not form a partition wall 17 adjacent to 16a
And the fuel exhaust gas 19 is discharged from a gas chamber 23 facing the fuel supply chamber 22. As a result, the gas chamber 1 that supplies the air 13
5a, 16a and a gas chamber 22 for supplying the fuel 14 are adjacent to each other, and gas chambers 15b, 16 for discharging the exhaust air 20 are provided.
b and the gas discharge chamber 23 for discharging the fuel exhaust gas 19, respectively, are adjacent to each other.
Gases having different temperature differences (supply gas and exhaust gas) do not coexist through a to 18d, there is no breakage due to thermal expansion, and a good seal can be maintained.

The sealing of the partition wall 17 does not need to be as strict as the sealing of the cell stack 12 and the cylindrical tube 11.
This is because the gases flowing through the partition walls 17 are gases having the same composition, so that there is no problem even if the gas leaks.

The supply form of the gas supplied to each cell is not limited at all, but an example of the supply form of the gas is shown below.

FIG. 2 is a view showing a gas flow state of the stack 12. As shown in FIG.
Is an opening 21 at one end of each cell 21 constituting the stack 12.
a, and supplies fuel to the fuel electrode 21A of the cell 21. Excess fuel is discharged as fuel exhaust gas 19 from the opening 21b at the other end. On the other hand, as shown in FIGS. 2 (b) and 2 (c), the air 13 is supplied to the air electrode 21B of the cell from the left and right alternately for each of the cells 21 of the multilayer structure. That is, in FIG. 2B, while the air 13 is introduced into the inside from the opening 21c provided at the lower left,
The exhaust air 20 is discharged from an opening 21d provided at the upper right in FIG. 2B. In the case shown in FIG. 2C, the air 13 is introduced into the inside through an opening 21e provided at the lower right in the figure, and the air exhaust gas 20 is discharged from the opening 12f provided at the upper left in FIG. 2C. Have been.

FIG. 3 is a sectional view taken along the line III-III of FIG.
FIG. 2B shows a state in which cells of the first type shown in FIG. 2B and cells of the second type shown in FIG. 2C are multi-layered to form openings alternately. Supply opening 21e
And a state in which an opening 21d for discharging the exhaust air 19 is formed.

In this embodiment, since the flow of air is reversed for each cell, the temperature distribution is made uniform throughout the stack body, and the battery reaction is activated. That is, as shown in FIG. 2B, the odd-numbered cells of the first type are supplied with air 13 from the lower opening 21c on the left side, and discharged from the upper opening 21d on the right side provided obliquely upward. Is done. The even-numbered cells of the second type are shown in FIG.
As shown in (c), the air 13 flows from the lower opening 21e on the right side.
Is supplied, and the exhaust air 20 is discharged from the upper opening 21f provided diagonally above.

As described above, by forming the air flow alternately, the heat balance is improved. That is, the first type of cell has a lower left lower temperature and a higher right upper temperature, whereas the second type of cell has a lower right lower temperature and a higher left upper temperature. Is repeated, the heat is averaged, so that the right and left heat balance can be achieved in the entire stack.

In the above-described embodiment, a cylindrical tube is used. However, the present invention is not limited to this, and an embodiment using a rectangular tube instead of the cylindrical tube will be described below. As shown in FIG. 4, the fuel cell according to the present embodiment has a square stack 32 provided inside
In a solid oxide fuel cell that supplies air 33 and fuel 34 therein, gas cylinders 35 and 36 formed between a cylindrical tube and a stack are provided between a cylindrical tube 31 and a stack 32. A partition 37 is provided along the axial direction, and the gas chambers 35 and 36 are divided into first chambers 35a and 36a and second chambers 35b and 36b.
8a to 38d, the first chambers 35a, 36a
To the gas chamber 42 where the partition 37 is not formed, the fuel 34 is supplied to the gas chamber 42 where the partition 37 is not formed, and the exhaust air 40 is discharged from the second chambers 35b and 36b.
3 discharges the fuel exhaust gas 39. The flow state of the gas in the stack 32 is the same as that in FIG.

In the present embodiment, the cylindrical tube is a perfect circular cylinder, but the present invention is not limited to this.
For example, the cylindrical tube may be elliptical, and the cross section of the cell stack provided inside may be rectangular. In particular, in the case of a structure in which the manifold of the air chamber requiring a large amount of gas is large, an elliptical type is preferable.

[0019]

As described above, according to the first aspect of the present invention, a cell stack including a flat plate type single cell and an interconnector is provided in a cylindrical tube, and air and fuel are contained in the stack. In a solid oxide fuel cell formed by forming a gas chamber for supplying a gas chamber, partition walls facing each other in the axial direction are provided between the cylindrical tube and the stack in a pair of gas chambers facing each other, and the gas chamber is divided into two. Therefore, the divided gas chambers can supply and discharge air, and the non-divided gas chambers can supply and discharge fuel. As a result, gas having different temperature differences can be supplied through the seal portion. (Supply gas and exhaust gas) do not coexist, there is no breakage due to thermal expansion, and a good seal can be maintained.

According to a second aspect of the present invention, in the first aspect, the gas chamber that is not divided and one of the divided gas chambers adjacent to the gas chamber are used as a gas supply chamber, and the other gas chamber that is not divided is used. Gas chamber and the other divided gas chamber adjacent to the gas chamber are used as gas discharge chambers, so that gas (supply gas and exhaust gas) having different temperature differences through a seal portion as in the related art. There is no coexistence, no breakage due to thermal expansion, and a good seal can be maintained.

According to the third aspect of the present invention, in the first aspect, a tube having a square cross section is used in place of the cylindrical tube, and a square stack is provided in the square tube. Similarly, the divided gas chamber can supply and discharge air, and the non-divided gas chamber can supply and discharge fuel. As a result, the gas having different temperature difference (supply Gas and exhaust gas) do not coexist, there is no breakage due to thermal expansion, and a good seal can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a fuel cell according to an embodiment.

FIG. 2 is a gas flow diagram of a fuel cell.

FIG. 3 is a sectional view taken along the line III-III of FIG. 1;

FIG. 4 is a schematic diagram of another fuel cell according to the present embodiment.

FIG. 5 is a schematic diagram of a prior art fuel cell.

FIG. 6 is a gas flow diagram of a prior art fuel cell.

[Explanation of symbols]

 Reference Signs List 11 cylindrical tube 12, 32 stack 13, 33 air 14, 34 fuel 15, 16, 35, 36 gas chamber 17, 37 partition wall 18a-18d, 38a-38d sealing material 19,39 fuel exhaust gas 20,40 air exhaust gas 21 cell 21A Fuel electrode 21B Air electrode 21a to 21f Opening 22,42 Fuel supply chamber 23,43 Gas exhaust chamber 31 Square tube

Claims (3)

[Claims] 1. A solid oxide fuel cell comprising: a cell stack including a flat plate type single cell and an interconnector provided in a cylindrical tube; and a gas chamber for supplying air and fuel is formed in the stack. A solid oxide fuel cell comprising a pair of gas chambers facing each other, wherein partition walls facing each other are provided along the axial direction between the cylindrical tube and the stack, and the gas chambers are divided into two. 2. The gas chamber according to claim 1, wherein the undivided gas chamber and one of the divided gas chambers adjacent to the gas chamber are gas supply chambers, and the other undivided gas chamber is adjacent to the gas chamber. A solid oxide fuel cell, wherein the other divided gas chamber is a gas discharge chamber. 3. The solid oxide fuel cell according to claim 1, wherein a square tube is used in place of the cylindrical tube, and a square stack is provided inside the square tube.