JP3389481B2 - Solid oxide fuel cell - Google Patents

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 is the same as the solid oxide fuel cell of the present invention except for a rectifying member, and therefore will be described with reference to FIG.

As shown in FIG. 1, a solid oxide fuel cell has a reaction chamber 51 in which an air chamber partition plate 61, a combustion chamber partition plate 63, and a fuel gas chamber partition plate 55 are used to form an air chamber A and a combustion chamber. B, a reaction 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.
3 are inserted and fixed in a plurality of cell insertion holes formed in the fuel cell 3, and the openings are formed from the combustion chamber partition plate 63 to the combustion chamber B.
One end of an air introduction pipe 59 fixed to the air chamber partition plate 61 is inserted into the inside thereof.

The combustion chamber partition plate 63 is formed with a fuel gas ejection hole for introducing an excess fuel gas into the combustion chamber B, and the fuel gas chamber partition plate 55 stores the fuel gas in the reaction chamber C.
A supply hole for supplying the inside is formed.

Further, in the reaction vessel 51, for example, a fuel gas inlet 53 for introducing a fuel gas composed of hydrogen, an air inlet 57 for introducing air, and an exhaust outlet for discharging the gas burned in the combustion chamber B. 67 is formed.

In such a solid oxide fuel cell, the air from the air chamber A is supplied into the solid oxide fuel cell unit 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 to the outside from the exhaust port 67.

[0008]

However, in the conventional cylindrical solid oxide fuel cell, as shown in FIG. 9, the opening of the bottomed cylindrical solid oxide fuel cell 52 is the combustion chamber partition plate 63. Since it protrudes into the combustion chamber B from the above, the distance d between the stack composed of the assembly of the plurality of solid oxide fuel cell units 52 and the inner wall surface of the reaction container 63 is long, and air wraps around the space between them, A mixed region G of fuel gas and air, that is, a combustion region was formed on the side of the opening. Therefore, there is a problem in that the side surface of the opening of the cell 52 protruding into the combustion chamber B is exposed to a high temperature spotwise and cracked by thermal stress. Due to the cracks in the openings, the entire cell may be damaged and the power generation performance may be deteriorated.

[0009]

Means for Solving the Problems As a result of studying the above problems, the inventors of the present invention have provided a rectifying member between the stack and the inner wall of the reaction chamber so as to come into contact with them, and By making the protrusion height from the combustion chamber partition plate higher than the protrusion height from the combustion chamber partition plate of the solid oxide fuel cell unit, it is possible to eliminate the combustion region on the side of the cell opening, The present inventors have found that it is possible to effectively reduce the thermal stress acting on the openings of the above, and have reached the present invention.

That is, the solid oxide fuel cell of the present invention is
A combustion chamber and a reaction chamber are formed by using a combustion chamber partition plate in the reaction container, and a plurality of bottomed cylindrical solid oxide fuel cell units are provided.
A plurality of cell insertion holes formed in the combustion chamber partition plate are inserted and fixed so that the openings project from the combustion chamber partition plate toward the combustion chamber side, and air is solid electrolyte fuel cell. The fuel gas is supplied into the cells, respectively, and the fuel gas is supplied between the solid oxide fuel cell cells in the reaction chamber to react with each other, and excess fuel gas is discharged from the fuel gas ejection holes formed in the combustion chamber partition plate. It is ejected into the combustion chamber and supplied into the solid oxide fuel cell unit to
From the opening of the solid oxide fuel cell into the combustion chamber
A solid oxide fuel cell for reacting with the introduced air to burn, wherein a rectifying member in contact with the inner wall surface of the reaction vessel is arranged at the outermost side of the solid electrolyte fuel cell assembly. The combustion chamber partition plate is provided so as to abut the electrolyte fuel cell, and the protruding height h ₁ of the rectifying member from the combustion chamber partition plate is the combustion chamber partition of the solid oxide fuel cell unit. It is higher than the protruding height h ₂ from the plate.

Here, it is desirable that the rectifying member is provided with an inclined portion at a position higher than the solid oxide fuel cell unit on the solid oxide fuel cell side.

[0012]

In the solid oxide fuel cell of the present invention, the rectifying member that comes into contact with the inner wall surface of the reaction vessel is provided on the combustion chamber partition plate so as to come into contact with the cells arranged on the outermost side of the cell assembly, and Height of protrusion of the rectifying member from the combustion chamber partition plate h ₁
Is set higher than the protruding height h ₂ of the cell from the partition plate of the combustion chamber, so that no space is formed between the opening of the cell and the inner wall surface of the reaction vessel, and the air to this space is not formed. The wraparound is eliminated, and the mixed region of fuel gas and air, that is, the combustion region is not formed on the side of the opening of the cell, but is always formed above the cell. Therefore, the sides of the openings of the cells arranged on the outermost side of the stack are directly exposed to the combustion area, and the spots do not become hot and the thermal stress acting on the cell edges is effectively reduced. it can.

Further, by providing the inclined portion on the solid electrolyte fuel cell side of the rectifying member at a position higher than that of the solid electrolyte fuel cell, the wraparound of air generated in the space above the rectifying member is reduced, No combustion region is formed on the side of the cell opening.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A 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 arranging a plurality of solid oxide fuel cells 52 in a reaction container 51. , A fuel gas inlet port 53 for introducing a fuel gas comprising hydrogen, a fuel gas chamber partition plate 55 for dispersing the fuel gas, an air inlet port 57 for introducing air, and an air inlet for introducing air into the cell 52. It is composed of a pipe 59, an air chamber partition plate 61 for fixing the air introducing pipe 59, and a combustion chamber partition plate 63 for fixing the cell 52.

Dispersion holes (not shown) for dispersing the fuel gas between the cells 52 are formed in the fuel gas chamber partition plate 55. Between the air chamber partition plate 61 and the combustion chamber partition plate 63 that fixes the cell 52, there is a combustion chamber B in which air and hydrogen burn.
As shown in FIG. 2B, the combustion chamber partition plate 63 is provided with combustion gas ejection holes 66 for introducing the fuel gas passing between the cells 52 into the combustion chamber B. The gas burned in (1) is discharged to the outside through the exhaust port 67 provided in the reaction vessel 51.

The plurality of cells 52 are inserted and fixed in a plurality of cell insertion holes formed in the combustion chamber partition plate 63, and excess combustion gas is introduced into the combustion chamber B through the combustion chamber partition plate 63. A fuel gas ejection hole 66 is formed. The air introduction pipe 59 is inserted and fixed in an air introduction pipe insertion hole formed in the air chamber partition plate 61. Partition plates 55, 6
Reference numerals 1 and 63 prevent gas leakage in the chambers A, B, C, and D.

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. 4, one cell 5
The second interconnector 74 is connected to the fuel electrode 73 of the other cell 52 via the connecting member 75 such as Ni metal fiber to the fuel electrode 73 of the other cell 52 to electrically connect the plurality of cells 52. The stack 77 is formed, and such a stack 77 is housed in the reaction vessel 51 as shown in FIG. 1 to form a solid oxide fuel cell. In the reaction vessel 51, the electrode 78 connected to the interconnector 74 of one cell 52 and the other cell 52
An electrode (not shown) connected to the fuel electrode 73 is disposed, and electric power is taken out through these electrodes 78.

In the solid oxide fuel cell of the present invention, as shown in FIGS. 5 and 6, an annular rectifying member is provided between the inner wall surface of the reaction vessel 51 and the stack 77 which is an assembly of the cells 52. 83 is arranged, and the rectifying member 83 is
The side surfaces on both sides of the flow regulating member 83 are respectively formed so that no space is formed between the inner wall surface of the reaction container 51 and the openings of the cells 52 arranged on the outermost side of the stack 77.
It is in contact with the inner wall surface and the side surface of the opening of the cell 52. The protruding height h ₁ of the rectifying member 83 from the combustion chamber partition plate 63 is set higher than the protruding height h ₂ of the cell 52 from the combustion chamber partition plate 63. The height h ₁ of the rectifying member 83 is equal to that of the cell 5
20 mm or more higher than the protruding height h _{2 of} No. ₂ is desirable in that the combustion region is less susceptible to the influence of the air flowing above the flow regulating member 83.

In the power generation of such a solid oxide fuel cell, air is introduced from the air introduction port 57 into the cell 52 through the air introduction pipe 59, and hydrogen is introduced from the fuel gas introduction port 53. It is carried out by dispersing in the dispersion holes of the fuel gas chamber partition plate 55 and introducing it to the outside of the cell 52. Excess air and fuel gas are burned in the combustion chamber 65 and discharged from the exhaust port 67 to the outside. .

FIG. 7 shows the gas flow of one solid oxide fuel cell unit. Hydrogen gas (fuel gas) is introduced from the lower side of the fuel cell and is oxidized by power generation and proceeds upward. On the other hand, air (oxidizing gas) is introduced from above the cell to below the inside of the cell via the air introduction pipe 59. Then, it flows from the lower part inside the cell to the upper part. The air discharged from the upper part of the cell reacts with the hydrogen gas that has not been consumed in the power generation, and burns in the combustion chamber 65.

In the solid oxide fuel cell configured as described above, the annular rectifying member 83 which is in contact with the inner wall surface of the reaction vessel 51 and is formed along the reaction vessel 51 is
Outermost cell 5 of stack 77 of cells 52
2 is provided on the combustion chamber partition plate 63 so as to be in contact with 2, and the protruding height h ₁ of the rectifying member 83 from the combustion chamber partition plate 63 is
Since the height of protrusion of the cell from the combustion chamber partition plate 63 is made higher than the height h ₂ , a space is not formed between the opening of the stack 77 of the cell 52 and the inner wall surface of the reaction vessel 51. Since the air does not wrap around to the fuel gas and the air, the mixed region, that is, the combustion region is not formed on the side of the opening of the cell 52. Therefore, stack 77
The sides of the openings of the cells arranged on the outermost side of the cell are directly exposed to the combustion area, and the situation where the spot temperature becomes high does not occur and the thermal stress acting on the cell edge can be effectively reduced. It is possible to suppress damage to the opening of 52.

As shown in FIG. 8, when a sloping portion 85 is provided on the rectifying member 83 at a position higher than the solid oxide fuel cell unit 52 on the cell 52 side, the air generated in the space above the rectifying member 83 is formed. It is possible to further suppress the formation of a combustion region on the side of the opening of the cell 52, which is further suppressed. The angle θ between the inclined surface of the inclined portion 85 and the cell axis is preferably 10 to 30 degrees.

[0025]

EXAMPLES As an air electrode material, La _0.9 Sr _0.1 MnO ₃ and La _0.9 Sr having a purity of 99.9% and an average particle size of 5 μm were used.
_The purity of _0.1 CoO ₃ as a solid electrolyte material is 99.9.
% ZrO ₂ containing 10 mol% Y ₂ O ₃ having an average particle size of 0.7 μm has a purity of 9% as an interconnector material.
La _0.8 Ca _0.22 CrO with 9.9% and average particle size of 1 μm
₃ powder, 80 wt% as the fuel electrode material Ni or Ru
ZrO ₂ containing each was prepared.

La _0.9 Sr _0.1 MnO ₃ powders were respectively extruded and sintered to obtain hollow cylindrical air electrodes having an outer diameter of 18 mm, a thickness of 2.3 mm and a length of 300 mm after sintering. Thereafter, a ZrO ₂ powder containing 10 mol% Y ₂ O _3, after producing a solid electrolyte sheet and the interconnector sheet having a thickness of 150μm by a doctor blade method using the La _{0. 8} Ca _0.22 CrO ₃ powder, Wrap each sheet around the above air electrode, and
It was baked at 00 ° C. for 3 hours and baked on the air electrode. Further, a slurry composed of ZrO ₂ powder containing 80% by weight of NiO or Ru is applied on the surface of the solid electrolyte, and the temperature is set to 1400 ° C.
After baking for 2 hours, a solid oxide fuel cell as shown in FIG. 3 was produced. The thickness of the solid electrolyte is 100μ
It was m.

Sixteen cylindrical solid oxide fuel cell units were connected in 4 series and 4 parallel to form a stack, and the stack was placed in a reaction vessel as shown in FIG. In addition, the protruding height h ₂ of the cell from the combustion chamber partition plate was 15 mm. Then, a solid oxide fuel cell of the present invention in which a rectifying member was arranged between the combustion chamber partition plate and the stack, and a conventional solid oxide fuel cell in which no rectifying member was arranged were produced. The protruding height h ₁ of the rectifying member from the combustion chamber partition plate is 35
mm.

Then, 40 SLM of air was flown inside the air electrode and 6.3 SLM of hydrogen gas was flowed on the fuel electrode side to set the temperature of the power generation furnace to 1000 ° C. to generate electricity. In this power generation test, the temperature near the opening of the cell after 5 minutes was measured using a thermocouple, and it was about 1238 ° C. in the conventional solid oxide fuel cell without the rectifying member, and the rectifying member was provided. In the solid oxide fuel cell of the present invention, about 1
It was 118 ° C. From this, it is understood that the thermal stress acting on the cell edge can be effectively reduced.

[0029]

In the solid oxide fuel cell of the present invention, an annular rectifying member that is in contact with the inner wall surface of the reaction vessel and is formed along the reaction vessel is arranged at the outermost side of the cell assembly. Provided on the partition plate of the combustion chamber so as to abut
Moreover, the protrusion height h ₁ of the flow regulating member from the combustion chamber partition plate is
Since the height of protrusion of the cell from the partition plate of the combustion chamber is set to be higher than h ₂ , a space is not formed between the opening of the cell assembly (stack) and the inner wall surface of the reaction vessel. There is no air wraparound in the space, the mixed area of fuel gas and air, that is, the combustion area is not formed on the side of the cell opening, and the thermal stress acting on the cell edge can be effectively reduced. It is possible to prevent breakage of the cell opening.

[Brief description of drawings]

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

FIG. 2 shows a combustion chamber partition plate and its vicinity,
(A) is a side view and (b) is a plan view.

FIG. 3 is a cross-sectional view of a solid oxide fuel cell mole.

FIG. 4 is a plan view showing a stack.

FIG. 5 is a schematic diagram of a solid oxide fuel cell showing a state in which a rectifying member is arranged.

6 is a cross-sectional view of FIG.

FIG. 7 is an explanatory diagram for explaining a gas flow in a solid oxide fuel cell unit.

FIG. 8 is a schematic diagram of a solid oxide fuel cell in which a rectifying member is formed with an inclined portion.

FIG. 9 is a schematic view of a conventional solid oxide fuel cell.

[Explanation of symbols]

51 ... Reaction container 52 ... Solid oxide fuel cell 55 ... Fuel gas chamber partition plate 61 ... Air chamber partition plate 63 ... Combustion chamber partition plate 83 ... rectifying member 85 ... Inclined part

Claims (2)

(57) [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. In the cell insertion hole of, the opening is inserted and fixed so as to project from the combustion chamber partition plate to the combustion chamber side, respectively, to supply air into the solid oxide fuel cell unit, and the fuel Gas is supplied between the solid oxide fuel cell units in the reaction chamber to react with each other, and excess fuel gas is jetted into the combustion chamber from a fuel gas jet hole formed in the combustion chamber partition plate to form the solid electrolyte. Type fuel cells
From the opening of the solid oxide fuel cell unit,
A solid oxide fuel cell that reacts with air introduced into a combustion chamber to burn, and a rectifying member that is in contact with the inner wall surface of the reaction container is arranged at the outermost side of the assembly of the solid oxide fuel cell units. Further, the combustion chamber partition plate is provided so as to come into contact with the solid oxide fuel cell unit, and the protruding height h ₁ of the rectifying member from the combustion chamber partition plate is
A solid oxide fuel cell, wherein the height of protrusion of the solid oxide fuel cell from the combustion chamber partition plate is higher than h ₂ . 2. The solid oxide fuel cell according to claim 1, wherein an inclined portion is provided at a position higher than the solid oxide fuel battery cell of the rectifying member on the solid oxide fuel cell side.