JP3238086B2 - 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 bottomed cylindrical solid oxide fuel cell.

[0002]

2. Description of the Related Art Conventionally, a solid oxide fuel cell has a high power generation efficiency because its operating temperature is as high as 900 to 1050 ° C., and is expected as a third generation power generation system.

[0003] In general, solid oxide fuel cells include:
A cylindrical type and a flat type are known. The flat fuel cell has the feature that the power density per unit volume of power generation is high, but there are problems such as imperfect gas sealing and non-uniformity of the temperature distribution in the cell in practical use. In contrast, cylindrical fuel cells have a low power density,
It has the features that the mechanical strength of the cell is high and that the temperature inside the cell can be kept uniform.

In both types of solid oxide fuel cells,
R & D is being actively promoted by taking advantage of each feature.

As shown in FIG. 3, a single cell of a cylindrical fuel cell has a support tube 1 made of CaO-stabilized ZrO ₂ having an open porosity of about 40%, and a porous air made of LaMnO ₃ material on the support tube 1. A pole 2 is formed, and Y ₂ O ₃ stabilized Zr is formed on its surface.
A solid electrolyte 3 made of O ₂ is covered, and a porous Ni-zirconia fuel electrode 4 is provided on this surface. In the fuel cell module, each single cell is LaC
It is connected via an rO ₃ -based current collector (interconnector) 5. Power generation is performed at a temperature of 900 to 1050 ° C. by flowing air (oxygen) 6 inside the support tube 1 and fuel (hydrogen) 7 outside.

In recent years, a LaMnO ₃ -based material, which is an air electrode material, has been used directly as a porous support tube in order to simplify the process in the cell manufacturing process. As a support tube material having the function as an air electrode, La
The LaMnO ₃ solid solution material obtained by substituting 10-15 atomic% in 20 atomic% or Sr with Ca is used.

As a method of manufacturing the above-described fuel cell, for example, an insulating powder composed of CaO-stabilized ZrO ₂ is formed into a cylindrical shape by an extrusion molding method or the like, and then fired to form a cylindrical support. A slurry of an air electrode, a solid electrolyte, a fuel electrode, and a current collector is applied to the outer peripheral surface of the support, and the slurry is sequentially fired and laminated, or the surface of the cylindrical support is electrochemically coated. An air electrode, a solid electrolyte, a fuel electrode, and a current collector are sequentially formed by a vapor deposition method (EVD method), a plasma spraying method, or the like.

Recently, a so-called co-sintering method has been proposed in which at least two of the constituent materials are simultaneously fired in order to simplify the manufacturing process of the cell. In this co-sintering method, for example, a solid electrolyte molded body and a molded body for a current collector are wound around a molded body of a cylindrical air electrode support tube in a roll shape and simultaneously fired, and then the fuel electrode is formed on the surface of the solid electrolyte layer. This is a method of forming a layer. This co-sintering method is advantageous for improving the yield and manufacturing cost during the production of the cell since the number of production steps is reduced.

Conventionally, one end of the cell is sealed by setting a cylindrical cell body obtained by sintering to a mounting member in a furnace for actually generating power, and forming a glass layer formed on the mounting member. Was brought into contact with one end of the cell body, the glass layer was melted at the time of temperature rise during power generation, and one end of the cell body was sealed with the mounting member.

Further, a bottomed cylindrical molded body for a sealing member is made of the same material as the air electrode molded body and the air electrode molded body, and one end of the air electrode molded body and one end of the molded body for the sealing member are connected. After the contact and firing, as described above, a solid electrolyte, such as an electrochemical deposition method (EVD method) or a plasma spray method,
A fuel electrode and a current collector are sequentially formed, and a dense ceramic layer is formed on the surface of the sealing member by an electrochemical vapor deposition method (EVD method) or a plasma spraying method to prevent gas leakage from the sealing member. I was

[0011]

However, according to the conventional method of sealing one end of a fuel cell with a mounting member using a glass material, the fuel cell is completely sealed when power is actually generated. It is difficult to confirm whether or not it is stopped, and it is easy for the single cell output to decrease due to poor sealing,
In particular, in the case of stacking, there is a problem that sealing failure is likely to occur due to an increase in the number of sealing portions, and as a result, the output is reduced.

Further, in the method of firing in a state in which one end of the cathode forming body and one end of the sealing member forming body are in contact with each other, it is difficult to join the cathode forming body and the sealing member, and furthermore, the gas leakage Electrochemical deposition method (EVD method)
It is necessary to form a dense ceramic layer on the surface of the sealing member by a plasma spraying method or the like, and there is a problem that the sealing step is troublesome and costly.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a solid oxide fuel cell which can easily and reliably perform gas sealing of a cell body and can easily confirm the gas seal.

[0014]

Means for Solving the Problems As a result of repeated studies on the above problems, the present inventors have found that a ceramic molded body for a sealing member is externally fitted to the outer peripheral surface of one end of the cell body and fired. ,
By fitting to one end of the cell body by firing shrinkage of the sealing member, it was found that one end of the cell body could be easily and reliably sealed, and that the sealed state could be easily confirmed, The present invention has been reached.

That is, in the solid oxide fuel cell of the present invention, an air electrode is formed on one surface and a fuel electrode is formed on the other surface of a cylindrical solid electrolyte, and the solid electrolyte is electrically connected to the air electrode or the fuel electrode. Solid electrolyte type fuel having a ceramic cap-shaped sealing member consisting of a base portion and a cylindrical portion externally fitted to an outer peripheral surface of one end of a cylindrical cell body provided with a current collector exposed on the outer surface. In the battery cell, the sealing member has the same outer diameter of the cylindrical portion and the base portion, and the inner diameter of the cylindrical portion when sintered alone is smaller than the outer diameter of the cell body. The molded body for a sealing member is fired by being in contact with one end of the cell body. When the outer diameter of the base portion is D ₁ and the outer diameter of the cylindrical portion is D ₂ , D ₁ / D ₂ satisfies the range of 0.74 to 0.88.

Here, it is desirable that a sealing member is externally fitted to the outer peripheral surface of one end of the cell body via a gas seal layer made of ceramics.

[0017]

The solid oxide fuel cell according to the present invention is different from the conventional one in that the cell body for power generation is set in a furnace and power is generated, instead of sealing one end of the cell body with a mounting member. At the manufacturing stage, one end of the cell body is sealed with dense ceramics, so that one end of the cell body can be easily and reliably sealed, and the sealed state before setting the power generation cell body in the furnace. Can be confirmed,
Gas sealing performance during power generation is sufficiently ensured.

That is, in the solid oxide fuel cell of the present invention, the ceramic molded body for a sealing member is fitted on the outer peripheral surface of one end of the cell body and fired, so that the ceramic molded body for a sealing member is obtained. The ratio D ₁ / D ₂ of the outer diameter D ₁ of the base portion of the sealing member to the outer diameter D ₂ of the cylindrical portion is 0.74 to 0.88.
Sintering to satisfy the range, the cylindrical portion of the sealing member is fitted to one end of the cell body, and at the same time, the outer surface of the cell body and the inner surface of the cylindrical portion of the sealing member are joined during firing, One end of the cell body can be easily and reliably sealed.

In particular, in the solid oxide fuel cell of the present invention, a ceramic slurry is applied to the outer peripheral surface of one end of the cell body to form a gas seal layer made of ceramics.
By fitting the sealing member to the outer peripheral surface, even when the current collector protrudes from the cell main body and the unevenness is formed on the outer peripheral surface of the cell main body, the sealing member is fitted by the gas seal layer. The outer peripheral surface of the cell main body in the portion to be formed is smoothed, the sealing member and the cell main body can be more closely adhered to each other without any gap, and the gas sealing property can be improved.

According to the method of the present invention, for example, when a ZrO ₂ or LaCrO ₃ porcelain is used as the sealing member, the firing temperature of the porcelain (1300 ° C. or higher) is set to the actual power generation temperature (1300 ° C. or more). (1000 ° C.), there is no risk of gas leak during power generation, and as a result, the reliability of the cell output and the long life can be achieved. Furthermore, when assembling a stack using a plurality of cells, the number of sealing portions at the stage of generating power can be reduced as much as possible, thereby facilitating system design.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The cell body according to the present invention forms a solid electrolyte on the surface of a cylindrical air electrode, forms a fuel electrode on the surface of the solid electrolyte, and is further electrically connected to the air electrode. A cell body is formed by providing a current collector.
In addition, you may manufacture the cell main body as shown in FIG.

As shown in FIGS. 1 and 2, a gas seal layer 9 made of ceramic is formed on the outer peripheral surface of one end of the cell body 8, and the surface of the gas seal layer 9 has a cap shape. The sealing member 11 made of dense ceramic is fitted outside, and the cell body 8, the gas seal layer 9, and the sealing member 11 are integrated by firing. That is, by applying a ceramic slurry to the outer peripheral surface of one end of the cell main body 8 to eliminate and flatten the outer peripheral surface of the cell main body 8, the ceramic molded body for a sealing member is externally fitted and fired. At the same time, the ceramic molded body for the sealing member shrinks by firing, and is fitted to one end of the cell body 8, and at the same time, the outer peripheral surface of the cell body 8 and the inner surface of the sealing member 11 are interposed via the gas seal layer 9 during firing. Are joined.

The gas seal layer 9 is made of, for example, a partially stabilized Z
Various materials such as rO ₂ , stabilized ZrO ₂ , and LaCrO ₃ can be used, but it is particularly preferable to use the same material as the solid electrolyte material from the viewpoint of the coefficient of thermal expansion. The thickness of the gas seal layer 9 may be such that the irregularities on the outer surface of the cell body 8 are eliminated, but is preferably 50 to 300 μm.

The sealing member 11 is made of dense ceramics to prevent gas leakage. The dense ceramics may be, for example, the same material as the gas seal layer 9. Further, similarly to the gas seal layer 9, it is desirable to form the same material as the solid electrolyte material from the viewpoint of the coefficient of thermal expansion. In the case of Y ₂ O ₃ partially stabilized ZrO ₂ , the coefficient of thermal expansion of the sealing member 11 and the gas seal layer 9 can be adjusted by changing the ratio of Y ₂ O ₃ to ZrO ₂ .

The sealing member 11 includes a cylindrical portion 13 into which the cell body 8 is inserted, and a base portion 14. The outer diameters of the cylindrical portion 13 and the base portion 14 are the same length, and the sealing member 11 is used alone. A molded body for a sealing member in which the inner diameter of the cylindrical portion 13 when sintered is smaller than the outer diameter of the cell body 8 is fired by abutting one end of the cell body 8. When the outer diameter of the base portion 14 of the sealing member 11 is D ₁ and the outer diameter of the cylindrical portion 13 is D ₂ , D ₁ / D ₂ is 0.74 to 0.
88 is satisfied. This is because, within this range, the sealing member 11 is tightly fixed to the outer surface of the cell body 8, and there is no gas leakage. Conversely, when D ₁ / D ₂ is smaller than 0.74, cracks occur between the cylindrical portion 13 and the base portion 14, and when D ₁ / D ₂ is larger than 0.88, the cell body 8 by the cylindrical portion 13 is formed. Is weak, and gas may leak from between the cell body 8 and the cylindrical portion 13. D ₁ / D ₂ is 0.77 to 0.2 from the viewpoint of improving gas sealing properties, preventing cracks in the sealing member 11, and being excellent in high-temperature load tests and cycle tests. 82 is desirable.

The thickness t of the cylindrical portion 13 of the sealing member 11 which is in contact with the outer surface of the cell body 8 is set so as to suppress the increase in the diameter of the cell and to prevent the cell from being damaged by the shrinkage stress during sintering. , 0.3 to 1.2 mm.

A method for manufacturing such a solid oxide fuel cell will be described in detail. First, in order to produce a cell main body, a cylindrical air electrode molded body having a function as a self-supporting tube is produced by extrusion molding, and thereafter, 1200 to 13
Binder removal and calcination are performed at a temperature of 00 ° C. for about 5 to 20 hours to produce a calcined cathode. This calcined cathode is
A LaMnO ₃ -based material having a perovskite-type crystal phase as a main phase, and having an average crystal grain size of 3 to 20 μm, particularly 5 to 1 μm.
Desirably, it is 5 μm. This is because if the particle diameter of the main crystal phase is smaller than 3 μm, the gas permeability is low although the strength is high, and if it exceeds 20 μm, the gas permeability is high but the strength is insufficient. The open porosity of the air electrode is suitably from 20 to 45%, particularly from 30 to 40%. An average pore diameter in the range of 1.0 to 5.0 μm is excellent in gas permeability.

Next, a molded layer of a material constituting the solid electrolyte is formed on the surface of the calcined cathode. This solid electrolyte molded body layer is prepared by using a powder of ZrO ₂ stabilized with a known stabilizer such as Y ₂ O ₃ having an average particle diameter of 0.5 to 3 μm to prepare a slurry, and then a doctor is prepared. It is formed by winding a green sheet produced by a blade method or the like.

Then, the air electrode / solid electrolyte molded body is
The calcined body is calcined at a temperature of 0 to 1300 ° C. for about 1 to 3 hours, and thereafter, the surface of the calcined solid electrolyte, which is a laminated portion of the current collector, is smoothly polished to expose the calcined cathode. A molded body for a current collector is laminated on the surface of the calcined body and the calcined cathode. The molded body for the current collector uses a LaCrO ₃ material,
It is formed by laminating green sheets in the same manner as the solid electrolyte molded body.

The laminate thus manufactured is heated at a temperature of 1300 to 1600 ° C. in an oxidizing atmosphere such as air at a temperature of 3 to 1600 ° C.
Co-sintering is performed by simultaneous firing for about 15 hours to produce a cylindrical cell body.

The fuel electrode uses a porous cermet material containing 30 to 80% by weight of Ni and the balance of stabilized ZrO ₂ (including a stabilizer such as Y ₂ O ₃ ). After forming a molded body layer at a predetermined portion of the sintered body and sintering, or after forming the air electrode / solid electrolyte / current collector molded body, a fuel electrode molded body is further laminated and fired simultaneously. Alternatively, a cylindrical cell body can be manufactured.

Next, for example, the same slurry as that of the solid electrolyte molded body is used, and for example, one end of the cell body is immersed (dipped) in the slurry, so that the ceramic slurry is applied to the outer surface of one end of the cell body. Apply, 100
Dry at ~ 150 ° C for 1-3 hours. Other methods of applying the ceramic slurry include spraying, brushing, and the like. It is desirable that the ceramic slurry be applied in an area slightly larger than a portion where the sealing member is externally fitted. The coating thickness is not particularly limited as long as the unevenness on the outer peripheral surface of the cell body is eliminated. In the present invention, such a step of applying the ceramic slurry (gas sealing layer) is not always necessary, but it is preferable to perform gas sealing more reliably.

Since the sealing member is required to have gas sealing properties during power generation, for example, ZrO ₂ -based or LaCrO ₃ -based oxide powder having an average crystal grain size of about 0.5 to 3 μm is extruded or subjected to hydrostatic pressure. It is formed by molding (rubber press) or the like, and cut into a cap shape to produce a ceramic molded body for a sealing member. It is desirable to use yttria partially stabilized zirconia for the gas seal layer and the sealing member.

At this time, the ceramic molding for a sealing member is
It is desirable that the thickness of the molded body of the cylindrical portion which abuts on the outer peripheral surface of the cell body and is tightened is 0.7 to 2.0 mm. This is because if the sealing member is thinner than 0.7 mm, the sealing member may be broken at the time of firing, and if it is thicker than 2.0 mm, a cell when a stack is formed by a plurality of solid oxide fuel cells. This is because electrical connection between them becomes difficult. In addition, since the outer diameter increases by the thickness of the cylindrical portion, it is required to reduce the thickness of the cylindrical portion of the sealing member in order to minimize the increase in the outer diameter as much as possible. Stabilized zirconia is preferred.

The inner diameter of the cylindrical portion of the ceramic molding for a sealing member into which one end of the cell body is inserted is preferably 1.05 to 1.25 times the outer diameter of the cell body. This is because when the inner diameter of the cylindrical portion is smaller than 1.05 times the outer diameter of the cell body, the sealing member is liable to crack due to distortion, and when the inner diameter is larger than 1.25 times the sealing member. This is because a gap may be formed between the cell and the cell body, and sealing may not be possible. The size, material, and the like of the ceramic molding for a sealing member are determined so that the inner diameter of the cylindrical portion when the sealing member is sintered alone is smaller than the outer diameter of the cell body.

Thereafter, as shown in FIG. 2, one end of the cell body is inserted into the cylindrical portion of the ceramic molding for the sealing member.
Baking for about 1 to 5 hours at a temperature of 1300 to 1600 ° C. in an oxidizing atmosphere such as the atmosphere, and fitting a sealing member to one end of the cell body via a gas seal layer to obtain a solid electrolyte type of the present invention. Obtain a fuel cell. The firing temperature of the ceramic molding for a sealing member is desirably in a range of 1350 ° C to 1500 ° C. That is, in order to newly sinter the sealing member after sintering the cell body, the sintering temperature of the gas seal layer and the sealing member is required to be lower than the sintering temperature of the cell body. For example, the sintering temperature of a fuel cell using a LaMnO ₃ -based material or the like is sintered at about 1500 ° C., but the yttria partially stabilized zirconia can be sintered at a lower temperature of about 1400 ° C. Yttria partially stabilized zirconia is preferable as the gas seal layer.

The sealing member and the gas seal layer are integrated at the time of firing, and the gas seal layer and the outer peripheral surface at one end of the cell body are integrated at the time of firing, whereby the sealing member is interposed through the gas seal layer. Is joined to the outer peripheral surface at one end. The sealing member made of the gas sealing layer and the dense ceramic only needs to be able to prevent gas leakage, and particularly preferably has a porosity of 5% or less.

The present invention is characterized in that one end of the cell main body is sealed with a sealing member, and the method for manufacturing the cell main body is not particularly limited, and the cell main body is manufactured by a known method other than the above-described method. May be.

Further, in the present invention, after the fuel electrode slurry is applied to a cell body having an air electrode, a solid electrolyte, and a current collector, the cell body is inserted into a cylindrical portion of a ceramic molding for a sealing member, and At the same time as the electrode coating film, the ceramic molded body for a sealing member may be baked to bake the fuel electrode on the surface of the solid electrolyte. In this case, a heat treatment step for burning only the fuel electrode can be omitted.

[0040]

【Example】

Example 1 In order to produce a cylindrical solid oxide fuel cell by co-sintering, first, a cylindrical air electrode molded body was produced as follows. La ₂ O ₃ , Y having a purity of 99.9% or more commercially available
Starting materials such as ₂ O ₃ , CaCO ₃ , and Mn ₂ O ₃ were weighed and mixed so as to have a composition of La _0.56 Y _0.14 Ca _0.3 MnO ₃ , then calcined at 1500 ° C. for 3 hours and pulverized to obtain an average particle size. A solid solution powder having a diameter of 5 μm was obtained. Further, a binder was added to the solid solution powder, and a cylindrical air electrode molded body was produced by an extrusion molding method. After drying, the air electrode molded product is 1
A cylindrical air electrode calcined body was prepared by debinding and calcining at 250 ° C. for 10 hours.

Next, Y ₂ O ₃ obtained by the coprecipitation method was
mol% ZrO ₂ having an average particle size of 1 μm
Toluene and a binder were added to the powder to prepare a slurry, and a 130 μm-thick solid electrolyte sheet was prepared by a doctor blade method.

Next, commercially available La _{2 having} a purity of 99.9% or more is used.
Starting from O ₃ , Cr ₂ O ₃ and MgO, this is
a (Mg _0.3 Cr _0.7 ) _0.97 O ₃ The mixture was weighed and mixed so as to obtain a composition, and then calcined at 1500 ° C. for 3 hours and pulverized to obtain a solid solution powder having an average particle diameter of 2 μm. Next, a slurry was prepared by adding toluene and a binder to the solid solution powder, and a current collector sheet having a thickness of 130 μm was prepared by a doctor blade method.

The solid electrolyte sheet was wound into a roll around the cylindrical air electrode calcined body, and calcined at 1100 ° C. for 3 hours. After calcination, the surface of the solid electrolyte calcined body which is to be a laminated portion of the current collector sheet is polished flat, and the surface is polished up to the exposed air electrode calcined body. Wrapped around. Then, at 1500 ° C in air
For 6 hours.

After co-sintering, ZrO ₂ (10 m
ol% Y ₂ O ₃ ) powder was mixed at a weight ratio of 80:20, water was added as a solvent to prepare a fuel electrode slurry, and a 50 μm thick fuel electrode slurry was applied to the surface of the laminated sintered body. It was applied and dried to produce a cell body having an outer diameter of about 15 mm and a thickness of 2 mm.

Next, water was added as a solvent to ZrO ₂ powder having an average particle size of 1 μm and containing Y ₂ O ₃ at a ratio of 3 mol% to prepare a slurry, and one end of the cell body was immersed in the slurry. And a thickness of 1 by the dipping method
A 00 μm ceramic slurry was applied to the outer peripheral surface of one end of the cell, and dried at 120 ° C. for 1 hour.

Next, a cap-shaped molded body as a sealing member is prepared. First, hydrostatic pressing (rubber pressing) is performed using a ZrO ₂ -based powder having the same composition as the slurry composition and containing Y ₂ O ₃ at a ratio of 3 mol% and an average particle diameter of 1 μm to form a cap. It was cut. Thereafter, one end of the cell coated with the slurry was inserted into a molded body for a sealing member. The dimensions of the outer diameter of the cylindrical portion and the base portion of the molded body for a sealing member were controlled such that the dimensions after sintering became the values shown in Table 1.

The thickness t of the cylindrical portion of the molded body for a sealing member which comes into contact with the outer peripheral surface of the cell body and tightens the cell body is 0.7 m.
m. That is, the length of the cylindrical portion of the molded body for a sealing member was 10 mm, the thickness t was 0.7 mm, and the length of the base portion in the axial direction was 8 mm. Note that the outer diameter of the cylindrical portion and the outer diameter of the base portion in the molded body were the same length.

Thereafter, the fuel electrode layer is formed by sintering at 1400 ° C. for 2 hours in the air, and a cap-shaped sealing member is provided on the outer peripheral surface of one end of the cell body via a gas seal layer. Mated. At this time, the outer diameters D ₁ and D ₂ of the base portion and the cylindrical portion were measured, and the ratio D ₁ / D ₂ was determined. When the molded body for a sealing member was baked independently at 1400 ° C. for 2 hours, the ratio of the outer diameter of the cylindrical portion of the sintered body to the outer diameter of the molded body was 75%.

Then, Air is pressurized and injected from the open end on the side where the sealing is not performed so that the internal air pressure inside the cell body becomes +1 kgf / cm ² higher than the external air pressure with respect to the external air pressure. Was submerged, and the presence or absence of air bubbles was judged based on the presence or absence of air bubbles. Table 1 shows the results.

[0050]

[Table 1]

According to Table 1, D ₁ / D ₂ is 74 to 88%.
When the range is satisfied, no leak occurs, but D ₁
/ D ₂ leakage occurs in 89% of the sample, 72% in the sealing member is damaged.

Example 2 The sample of Example 1 was left at a high temperature of 1000 ° C.
It was taken out after the lapse of 00 hours, 500 hours, and 1000 hours, cooled to room temperature, and examined for leaks in the same manner as described above. Further, even after a cycle load in which the step of cooling from 1000 ° C. to room temperature is repeated 10 times, the presence or absence of leakage was examined. The results are shown in Table 2.

[0053]

[Table 2]

From Table 2, D ₁ / D ₂ is 74-82%.
It can be seen that the composition has excellent characteristics at high temperature load in the range of. Then, from Table _2, D ₁ / D 2 is seen to be excellent also in the cooling load test and the cycle test in the case of 77 to 82%.

[0055]

As described in detail above, according to the present invention,
The outer diameter of the cylindrical portion and the base portion are the same length, and the inner diameter of the cylindrical portion when sintered alone is smaller than the outer diameter of the cell body. Bake by contacting one end, one end of the cell body at the cell manufacturing stage,
Sealing is performed with a dense ceramic sealing member via a gas seal layer, and an outer diameter D of a base portion of the sealing member.
₁ and the ratio D ₁ / D ₂ of the outer diameter D ₂ of the cylindrical portion to 0.74 to 0.1.
By setting the range to 88, it is possible to easily and reliably seal one end of the cell body, and to check the sealed state before setting the power generation cell body in the furnace. In this case, the gas sealing property is sufficiently ensured, and stable cell performance can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing the structure of a cylindrical fuel cell according to the present invention.

FIG. 2 is a cross-sectional view showing a state where one end of a cell main body is inserted into a cylindrical portion of a molding for a sealing member.

FIG. 3 is a perspective view showing a cell body of the solid oxide fuel cell.

[Explanation of symbols]

 8 Cell Body 9 Gas Seal Layer 11 Sealing Member 13 Cylindrical Part 14 Base

Claims (2)

(57) [Claims] An air electrode is formed on one surface of a cylindrical solid electrolyte, and a fuel electrode is formed on the other surface, and a current collector electrically connected to the air electrode or the fuel electrode and exposed on the outer surface is provided. In a solid oxide fuel cell unit, a ceramic cap-shaped sealing member consisting of a base portion and a cylindrical portion is externally fitted to an outer peripheral surface at one end of a cylindrical cell body provided, wherein the sealing member is An outer diameter of the cylindrical portion and the base portion is the same length, and the inner diameter of the cylindrical portion when sintered alone is smaller than the outer diameter of the cell body. When the outer diameter of the base is D ₁ and the outer diameter of the cylindrical part is D ₂ , D ₁ / D ₂ is 0.74 to 0.88. A solid oxide fuel cell that satisfies the following range: 2. The solid oxide fuel cell according to claim 1, wherein a sealing member is externally fitted to an outer peripheral surface of one end of the cell body via a gas seal layer made of ceramics.