JP2003077496A - Solid electrolyte fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolyte fuel cell that can maintain high generation performance for a long period by reducing effectively the thermal stress working on the opening part of the cell and by preventing breakage of the whole cell caused by cracking of the opening part of the solid electrolyte fuel cell. SOLUTION: This is a solid electrolyte fuel cell in which a combustion chamber B and a reaction chamber C are formed in a reaction container 51 by using a combustion chamber partition plate 62 and the cell 52 is inserted and fixed in the cell insertion hole 69 of the combustion chamber partition plate 62. And an oxygen-contained gas is supplied in the cell 52 and the fuel gas is supplied and reacted between the cells 52 in the reaction chamber C, and the surplus fuel gas in the reaction chamber C passes from the surplus gas vent 63 formed in the combustion chamber partition plate 62 to the combustion chamber B and is burnt by reacting with the oxygen-contained gas in the combustion chamber B. The surplus gas vent 63 is formed at the surroundings of the assembled body of a plurality of cells 52.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid oxide fuel cell, and more particularly to a solid oxide fuel cell in which a combustion chamber partition plate is used to form a combustion chamber and a reaction chamber.

[0002]

2. Description of the Related Art A conventional solid oxide fuel cell will be described with reference to FIG. As shown in FIG. 7, in the solid oxide fuel cell, the air chamber A, the combustion chamber B, the reaction chamber B, the reaction chamber 51, the reaction chamber 51, the reaction chamber 51, the combustion chamber partition plate 62, and the fuel gas chamber partition plate 55 are used. A chamber C and a fuel gas chamber D are formed.

A plurality of bottomed cylindrical solid oxide fuel cell units 52 housed in a reaction vessel 51 are composed of a combustion chamber partition plate 6.
2 are inserted into and fixed to a plurality of cell insertion holes formed in No. 2, and the openings are formed from the combustion chamber partition plate 62 to the combustion chamber B.
One end of an air introduction pipe 59 fixed to the air chamber partition plate 56 is inserted into the inside thereof.

The combustion chamber partition plate 62 has a fuel gas vent hole (not shown) for introducing excess fuel gas into the combustion chamber B.
The fuel gas chamber partition plate 55 has a supply hole (not shown) for supplying the fuel gas into the reaction chamber C.

Further, in the reaction vessel 51, for example, a fuel gas introduction port 53 for introducing a fuel gas composed of hydrogen, an air introduction port 57 for introducing air, and an exhaust port for discharging the gas burned in the combustion chamber B. 58 is formed.

In such a solid oxide fuel cell, the air from the air chamber A is supplied into the solid oxide fuel cell 52, and the fuel gas from the fuel gas chamber D is supplied to a plurality of solid oxide fuel cells. It is supplied between the battery cells 52, reacted in the reaction chamber C, burns excess air and fuel gas in the combustion chamber B, and the burned gas is discharged from the exhaust port 58 to the outside.

[0007]

However, in the conventional solid oxide fuel cell, as shown in FIG. 7, the opening of the bottomed cylindrical solid oxide fuel cell 52 is burned from the combustion chamber partition plate 62. Excess fuel gas vent holes are provided in a concentrated manner in the combustion chamber partition plate 62 near the opening of the chamber B. The excess fuel gas vent holes are provided from the surplus fuel gas vent holes or the cell insertion holes of the combustion chamber partition plate 62. Since the surplus fuel gas is ejected from the gap between the cell 52 and the cell 52, that is, the surplus fuel gas is ejected in the assembly of the plurality of cells 52, the cell 52
The combustion region is concentrated near the opening of the cell 52, and the vicinity of the opening of the cell 52 protruding into the combustion chamber B is exposed to a high temperature spotwise.
There was a problem of cracking due to thermal stress. Due to the cracks in the openings, the entire cell may be damaged and the power generation performance may be deteriorated.

The present invention effectively reduces the thermal stress acting on the opening of the cell, prevents the damage of the entire cell due to the cracking of the opening of the solid oxide fuel cell unit, and improves the power generation performance. An object is to provide a solid oxide fuel cell that can be maintained for a long period of time.

[0009]

A solid oxide fuel cell according to the present invention comprises a plurality of bottomed cylindrical solid oxide fuel cells in which a combustion chamber and a reaction chamber are formed by using a combustion chamber partition plate in a reaction container. Battery cells are inserted and fixed in a plurality of cell insertion holes formed in the combustion chamber partition plate so that the openings are opened to the combustion chamber, and an oxygen-containing gas or fuel gas is added to the solid electrolyte fuel. Each of them is supplied into a battery cell, and a fuel gas or an oxygen-containing gas is supplied between the solid oxide fuel cell cells in the reaction chamber to cause a reaction, and the excess fuel gas or oxygen-containing gas in the reaction chamber is Pass the excess gas vents formed in the combustion chamber partition plate to the combustion chamber,
A solid oxide fuel cell for reacting with an oxygen-containing gas or a fuel gas in the combustion chamber for combustion, wherein the excess gas vent holes are formed around an assembly of the plurality of solid oxide fuel cell units. It will be.

In such a solid oxide fuel cell, since the excess gas vent holes are formed around the assembly of a plurality of solid electrolyte fuel cell units, the excess fuel gas or oxygen passing through the excess gas vent holes is discharged. The contained gas is introduced into the combustion chamber from the outside of the assembly of cells and reacts with the oxygen-containing gas or the fuel gas in the combustion chamber to burn, so that the combustion position is separated from the cell and the temperature of the cell opening can be lowered. As a result, the thermal stress generated in the opening of the cell can be reduced, cracking of the cell opening can be prevented, damage to the entire cell can be prevented, and high power generation performance can be maintained for a long period of time.

Further, in the present invention, the fuel gas is substantially evenly distributed between the plurality of solid oxide fuel cell units at a predetermined distance from the combustion chamber partition plate on the cell bottom side of the combustion chamber partition plate in the reaction vessel. Alternatively, it is preferable that a gas dispersion partition plate for dispersing the oxygen-containing gas is provided, and the solid electrolyte fuel cell unit is inserted through the cell insertion hole formed in the gas dispersion partition plate.

According to such a construction, the partition plate for gas dispersion allows the fuel gas or the oxygen-containing gas introduced into the reaction chamber to be substantially evenly distributed among the plurality of solid oxide fuel cell units, and the surplus gas. The fuel gas or the oxygen-containing gas is supplied, for example, from the gap between the cell insertion hole of the gas dispersion partition plate and the solid oxide fuel cell unit to the gas flow control chamber between the gas dispersion partition plate and the combustion chamber partition plate. The excess fuel gas or oxygen-containing gas is forcibly introduced into the combustion chamber from the excess gas vent holes formed around the cell assembly in the gas flow control chamber. , As described above, the temperature of the opening in the cell assembly can be lowered, which can reduce the thermal stress generated in the opening of the cell, prevent cracking of the cell opening, and prevent damage to the entire cell. And high power The ability for a long period of time can be maintained.

Further, in the present invention, it is desirable that the gap between the cell insertion hole of the combustion chamber partition plate and the solid oxide fuel cell be sealed. By adopting such a configuration, surplus fuel gas or oxygen-containing gas can be forcibly introduced into the combustion chamber through the surplus gas vent holes formed around the cell assembly.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The solid oxide fuel cell of the present invention will be described with reference to FIG. In the case of a member similar to that of the conventional technique, the same reference numeral as that of the conventional technique is given.

As shown in FIG. 1, the solid oxide fuel cell of the present invention is constructed by accommodating a plurality of solid oxide fuel cell units 52 in a reaction container 51. , A fuel gas inlet port 53 for introducing a fuel gas composed of hydrogen, a fuel gas chamber partition plate 55 for dispersing the fuel gas, and a gas dispersion partition plate 61 for allowing excess fuel gas to pass from the reaction chamber C to the combustion chamber B. And the combustion chamber partition plate 62,
For example, an air introduction port 57 for introducing an oxygen-containing gas composed of air, an air introduction pipe 59 for introducing air into the cell 52, and an air chamber partition plate 56 for fixing the air introduction pipe 59 are configured. .

The fuel gas chamber partition plate 55 is provided with a plurality of dispersion holes (not shown) for uniformly dispersing the fuel gas between the cells 52 when the reaction chamber C is introduced into the fuel gas chamber partition plate 55. The bottom of the cell 52 is supported by. In addition, the bottom of the cell 52 is fixed to the plurality of cells 52 by the holding member 60.
Are held and fixed at predetermined intervals.

As shown in FIG. 2, in the gas dispersion partition plate 61, a gap 6 is formed between the cell insertion hole 65 and the outer surface of the cell 52.
7 is provided to allow excess fuel gas to pass through. It should be noted that the gap 67 between the cell insertion hole 65 and the outer surface of the cell 52 may be sealed to form an excess fuel gas vent hole in the gas distribution partition plate 61, but by using the gap 67. ,
Since the fuel gas or the oxygen-containing gas flows along the electrochemical reaction surface of the cell and the fabrication is easy, the cell insertion hole 6
It is desirable to provide a gap 67 between the cell 5 and the outer surface of the cell 52.

Gas distribution partition plate 61 and combustion chamber partition plate 62
A gas flow control chamber E for controlling the flow of the surplus fuel gas is formed between and. Between the combustion chamber partition plate 62 and the air chamber partition plate 56 is a combustion chamber B in which air and hydrogen burn.
As shown in FIG. 3, the combustion chamber partition plate 62 is provided with a plurality of surplus gas vent holes 63 around the assembly of the cells 52 for introducing surplus fuel gas into the combustion chamber B. The gap 52 is gas-sealed and sealed. still,
This gap does not have to be completely sealed.

The amount of protrusion of the cell opening from the combustion chamber partition plate 62 and the installation interval between the combustion chamber partition plate 62 and the gas dispersion partition plate 61 are each set to 5 mm or less. Is 20 mm or less.

The plurality of cells 52 are inserted and fixed in a plurality of cell insertion holes 69 formed in the combustion chamber partition plate 62, and the air introduction pipe 59 is an air introduction pipe insertion hole formed in the air chamber partition plate 56. It is inserted and fixed to (not shown). The partition plates 55, 61, 62 and 56 are used for the chambers A, B, C, D and E, respectively.
Gas leakage is prevented.

The gas burned in the combustion chamber B is the reaction vessel 51.
It is discharged to the outside through an exhaust port 58 provided in the.

The cell 52 is, for example, as shown in FIG.
LaMnO ₃ system air electrode 71 as a support tube, solid electrolyte 72 formed of Y ₂ O ₃ stabilized ZrO ₂ formed on the surface of this air electrode 71, and Ni-zirconia system formed on the surface of solid electrolyte 72 Of the fuel electrode 73 and an interconnector 74 of LaCrO ₃ system electrically connected to the air electrode 71.

Then, as shown in FIG. 5, one cell 5
The interconnector 74 of No. 2 is connected to the fuel electrode 73 of the other cell 52 via the connecting member 75 such as Ni metal fiber, so that the plurality of cells 52 are electrically connected, and the stack 77 is formed.
As shown in FIG. 1, such a stack 77 is housed in the reaction vessel 51 to form a solid oxide fuel cell.

In the power generation of such a solid oxide fuel cell, air is introduced into the cell 52 from the air introduction port 57 through the air introduction pipe 59, and hydrogen is introduced from the fuel gas introduction port 53 to generate the fuel gas. It is carried out by uniformly dispersing it in a plurality of dispersion holes of the chamber partition plate 55 and introducing it to the outside of the cell 52, and maintaining the cell 52 at 1000 ° C., so that excess air and fuel gas are burned in the combustion chamber B. And is discharged to the outside through the exhaust port 58.

FIG. 6 shows the gas flow of one solid oxide fuel cell unit 52. Hydrogen gas (fuel gas) is the cell 52
It is introduced from below, and proceeds upward while being oxidized by power generation. On the other hand, air (oxygen-containing gas) is introduced from above the cell 52 to below the inside of the cell through the air introduction pipe 59, turns back, and flows upward from below the inside of the cell. The air discharged from the upper part of the cell reacts with the surplus hydrogen gas that has not been consumed in the power generation, and burns in the combustion chamber B.

In the present invention, since the gap 67 is formed between the outer surface of the cell 52 and the cell insertion hole 65 of the gas dispersion partition plate 61, the fuel gas introduced through the dispersion hole of the fuel gas partition plate 55 is formed. Flows almost uniformly between the cells 52 along the cells 52, and excess fuel gas that could not contribute to power generation is introduced into the gas flow control chamber E through the gap 67, but the cells of the combustion chamber partition plate 62 are Since the gap between the insertion hole 69 and the cell 52 is gas-sealed, the surplus fuel gas in the gas flow control chamber E is provided at the outer edge of the combustion chamber partition plate 62, that is, around the assembly of the cells 52. Excess gas vent for fuel gas 6
3 is forcibly introduced into the combustion chamber B and reacts with air in the combustion chamber B to burn.

In the solid oxide fuel cell constructed as described above, the surplus gas vent holes 63 for the surplus fuel gas are provided in the corresponding combustion chamber partition plate 62 around the assembly of the cells 52. Excess fuel gas passing through the ventilation holes 63 is introduced into the combustion chamber B from the outside of the assembly of the cells 52,
While reacting with the air in the combustion chamber B and burning, the temperature around the assembly of the cells 52 becomes the highest temperature, while the temperature of the opening of the cell 52 can be lowered, and thus the temperature of the opening of the cell 52 is generated. Thermal stress can be reduced, cracks in the cell openings can be prevented, damage to the entire cell can be prevented, and high power generation performance can be maintained for a long time.

Further, a gas dispersion partition plate 61 is provided at a predetermined distance from the combustion chamber partition plate 62, and the gas dispersion partition plate 6 is provided.
Since the solid oxide fuel cell unit 52 is inserted through the cell insertion hole 65 formed in No. 1, the excess fuel gas is introduced into the combustion chamber B by the combustion chamber partition plate 62 and the gas dispersion partition plate 61. Through the gas flow control chamber E between
3 is supplied to the wall side of the reaction vessel 51 away from the cell 52 and can be burned at a position away from the cell 52, and the surplus fuel gas is discharged from the cell insertion hole 65 of the gas dispersion partition plate 61 and the cell 52. Since the gas flows through the gap 67, the fuel gas in the reaction chamber C flows along the cells 52 evenly between the cells 52, and the power generation performance can be improved.

Further, the cell insertion hole 6 of the combustion chamber partition plate 62.
Since the gap between the cell 9 and the cell 52 is sealed, the surplus fuel gas is reliably supplied from the surplus gas vent hole 63 through the gas flow control chamber E to the wall side of the reaction vessel 51 which is distant from the cell 52. it can.

The amount of protrusion of the cell opening in the combustion chamber partition plate 62, and the combustion chamber partition plate 62 and the gas dispersion partition plate 6
Since the cells each having an installation interval of 1 of 5 mm or less and a non-power generation area on the cell opening end side of 20 mm or less can be used, the power generation area on the cell surface can be expanded and the fuel utilization rate can be increased. And the combustion temperature in the combustion chamber B can be lowered. Therefore,
The combustion region in the combustion chamber B can be moved away from the vicinity of the cell opening, the combustion temperature can be lowered, and the thermal stress acting on the cell opening can be effectively reduced.

In the above example, the solid electrolyte 72 and the fuel electrode 73 are formed on the outer surface of the air electrode 71, and the fuel gas is flown outside the cell 52 and the air is flown inside the cell 52. The same effect can be obtained by forming a solid electrolyte and an air electrode in the cell and flowing air to the outside of the cell and flowing fuel gas to the inside of the cell.

[0032]

In the solid oxide fuel cell of the present invention, since the surplus gas vent holes are formed around the assembly of the plurality of solid electrolyte fuel cell units, the surplus fuel gas passing through the surplus gas vent holes is formed. Or, the oxygen-containing gas is introduced into the combustion chamber from the outside of the assembly of cells, and reacts with the oxygen-containing gas or the fuel gas in the combustion chamber to burn, so that the combustion position is separated from the cell and the temperature of the opening of the cell is reduced. This can reduce the thermal stress generated in the opening of the cell, prevent cracking of the cell opening, prevent damage to the entire cell, and maintain high power generation performance for a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a solid oxide fuel cell of the present invention.

FIG. 2 is a plan view of a gas dispersion partition plate.

FIG. 3 is a plan view of a combustion chamber partition plate.

FIG. 4 is a cross-sectional view of a solid oxide fuel cell unit.

FIG. 5 is a cross-sectional view showing a stack.

FIG. 6 is an explanatory diagram showing a gas flow in a solid oxide fuel cell unit.

FIG. 7 is a schematic view of a conventional solid oxide fuel cell.

[Explanation of symbols]

51 ... Reaction container 52 ... Solid oxide fuel cell 61 ... Partition plate for gas dispersion 62 ... Combustion chamber partition plate 63 ... Excess gas vent 65 ... Cell insertion hole of partition plate for gas dispersion 67 ... Gap 69 ... Cell insertion hole of combustion chamber partition plate B ... Combustion chamber C ... Reaction chamber

Claims (4)

[Claims] 1. A combustion chamber partition plate is used in a reaction vessel to form a combustion chamber and a reaction chamber, and a plurality of bottomed cylindrical solid oxide fuel cell units are formed on the combustion chamber partition plate. The cell insertion holes of the respective are inserted and fixed so that the openings are opened to the combustion chamber, and the oxygen-containing gas or the fuel gas is supplied into the solid oxide fuel cell, respectively, and the fuel gas or the oxygen is supplied. The containing gas is supplied between the solid oxide fuel cell units in the reaction chamber to react with each other, and the excess fuel gas or oxygen-containing gas in the reaction chamber is passed through the excess gas vent hole formed in the combustion chamber partition plate. A solid oxide fuel cell which is passed through to a combustion chamber and is reacted with an oxygen-containing gas or a fuel gas in the combustion chamber and burned, wherein the surplus gas vent hole is an assembly of the plurality of solid oxide fuel battery cells. Shaped around Solid oxide fuel cell, characterized in that to become to. 2. A fuel gas or an oxygen-containing gas in a plurality of solid oxide fuel cell units in a reaction vessel on the cell bottom side with respect to the combustion chamber partition plate at a predetermined distance from the combustion chamber partition plate. 2. A solid electrolyte fuel cell according to claim 1, wherein a partition plate for gas dispersion for dispersing is provided, and the solid electrolyte fuel cell unit is inserted through a cell insertion hole formed in the partition plate for gas dispersion. Type fuel cell. 3. The solid oxide fuel cell according to claim 1, wherein a gap between the cell insertion hole of the combustion chamber partition plate and the solid oxide fuel cell is sealed. 4. A gap is formed between the cell insertion hole of the gas dispersion partition plate and the solid oxide fuel cell unit, and the fuel gas or the oxygen-containing gas passes through the gap. Item 3. A solid oxide fuel cell according to item 2 or 3.