JP3100959B1 - Molten carbonate fuel cell suitable for degreasing holding material sheets and electrolyte sheets - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To appropriately control gas permeability and sealability of a wet seal portion. SOLUTION: With two cell frames 26 having concave portions for accommodating the electrodes 10 and 12 on the inner surface and having a large number of gas flow paths 18 in the concave portions, the two electrodes 10, 12 and the electrolyte between the electrodes are provided. In a molten carbonate fuel cell in which the plate 30 is sandwiched and the electrolyte plate 30 is sandwiched at the periphery of the cell frame 26 to form a wet seal portion 34, a holding material sheet is provided on the surface of the cell frame 26 of the wet seal portion 34. The air necessary for the electrolyte sheet to be degreased and fired is circulated, and the defatted and fired holding material is impregnated with the molten carbonate as an electrolyte to form the molten carbonate 3 when the electrolyte plate 30 is formed.
2 are sufficiently filled to form a concavo-convex portion 28 for exhibiting the function of a wet seal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet seal portion which secures a flow of air during degreasing and firing of an electrolyte plate, and after impregnation of the electrolyte plate with a molten salt, a liquid is filled between the electrolyte plate and a holding material to form a wet seal. The present invention relates to a molten carbonate fuel cell having a function.

[0002]

2. Description of the Related Art First, a process from assembly of a unit cell to formation of an electrolyte plate in a molten carbonate fuel cell will be described with reference to FIG. As shown in FIG. 11A, at the time of assembling the battery, a ceramic powder for holding an electrolyte is provided between two electrodes 10 and 12 of a fuel electrode (anode) 10 and an air electrode (cathode) 12. A holding material sheet 14 including an organic binder and the like, and a plurality of electrolyte sheets 16 including a carbonate serving as an electrolyte and an organic binder are stacked and arranged. The laminate of the holding material sheet 14 and the electrolyte sheet 16 sandwiched between the electrodes 10 and 12 has two cell frames 20 each having a concave portion for accommodating the electrode on the inner surface and having a large number of gas channels 18 in the concave portion. The cell frame 20 is sandwiched between the holding material sheet 14 and the electrolyte sheet 1.
6 is in contact with the laminate.

The assembled cell is shown in FIG.
As shown in (2), the temperature is raised to about 450 ° C., and the organic binder and the like contained in the holding material sheet 14 and the electrolyte sheet 16 are degreased. In the holding material sheet 14, the organic binder and the like are removed by burning, leaving only ceramics, and a porous body of ceramics is formed. In the electrolyte sheet 16,
The organic binder and the like are removed by burning, leaving only the carbonate which becomes the electrolyte. Thereafter, the temperature is further raised to about 650 ° C. to melt the carbonate, and the molten carbonate is impregnated into the holding material formed of the ceramic porous body, thereby forming the electrolyte plate 22 as shown in FIG. Is done. The contact surface between the electrolyte plate 22 and the peripheral portion of the cell frame 20 sandwiching the electrolyte plate 22 is sealed by being filled with molten carbonate, and the wet seal portion 24 is provided.
Are formed. In this state, the fuel electrode (anode) 1
The fuel gas is supplied to the gas flow path 18 on the 0 side, and the oxidizing gas is supplied to the gas flow path 18 on the air electrode (cathode) 12 side to cause a reaction to start the battery.

[0004]

In the molten carbonate fuel cell as described above, the surface of the cell frame is made as smooth as possible in order to enhance the sealing property of the wet seal portion. Rz (described below) is considered to be less than 3 μm. However, in a wet seal portion having a smooth cell frame surface, i.
In the degreasing of the electrolyte plate and the molten salt impregnation performed in the n-situ, the air (oxygen) required for the degreasing and firing does not sufficiently flow to the wet seal portion, so that there is a possibility that organic components such as a binder may not be sufficiently degreased. there were. That is, as shown in FIG. 12, after the battery assembly, when the degreasing of the organic binder contained in the holding material sheet 14 and the electrolyte sheet 16 is performed, the surface of the cell frame 20 is smooth, and the sheet and the cell frame 20 If not enough air flows between
As the amount of oxygen necessary for burning the binder etc. is not secured, FIG.
In the portion surrounded by the chain line circle of No. 2, organic components such as a binder could not be sufficiently degreased.

As described above, if the process proceeds to the molten salt impregnation step with insufficient degreasing of the organic binder and the like, the ceramic porous body serving as the holding material is not sufficiently formed, so that there is no place for the molten salt to go. In such a case, the electrolyte plate in the wet seal portion is damaged, causing gas leakage and causing a decrease in battery performance. For such issues,
Until now, no fundamental countermeasures have been taken.In order to reduce inconvenience due to poor degreasing and baking of the electrolyte plate, it is necessary to perform degreasing and baking over a long period of time, or to reduce the organic content in the molded sheet that is the precursor of the electrolyte plate. There was no method other than minimizing components (such as binders).

The present invention has been made in view of the above points, and an object of the present invention is to provide a wet-sealed portion in a molten carbonate type fuel cell by providing appropriate unevenness on the surface of the cell frame to degrease and fire the electrolyte plate. Occasionally, air circulation is ensured, and after impregnating the electrolyte plate with the molten salt, a molten salt (electrolyte solution) is filled between the electrolyte plate and the holding material to provide a function of a wet seal, so that oxygen can be removed at the time of degreasing the binder etc. Insufficient supply of oxygen is supplied to the wet seal part to prevent incomplete degreasing of binders and the like, shorten the degreasing time, and at the time of battery operation after molten salt impregnation, wetting by molten salt It is an object of the present invention to provide a molten carbonate fuel cell capable of ensuring the original sealing performance.

[0007]

In order to achieve the above object, a molten carbonate fuel cell suitable for degreasing a holding material sheet and an electrolyte sheet according to the present invention has a concave portion for accommodating an electrode on an inner surface thereof. Two electrodes and an electrolyte plate between the electrodes are sandwiched between two cell frames provided with a large number of gas flow paths in the concave portion, and an electrolyte plate is sandwiched between peripheral portions of the cell frame to form a wet seal portion. In the molten carbonate fuel cell
The surface of the cell frame of the wet seal portion is circulated with air necessary for the holding material sheet and the electrolyte sheet to be degreased and fired, and the defatted and fired holding material is impregnated with the molten carbonate as an electrolyte. to exhibit the function of the wet seal molten carbonate in the electrolyte plate is formed is sufficiently filled, the battery from the portion in contact with the internal electrode cell
An uneven portion having a form penetrating outside is formed (see FIGS. 1 to 4).

In the molten carbonate fuel cell according to the present invention, the ten-point average roughness Rz of the uneven portion formed on the cell frame surface of the wet seal portion is 3 to 150 μm, preferably 3 to 100 μm, and particularly preferably. The thickness is preferably 10 to 50 μm (see FIG. 7). The ten-point average roughness R
z extracts a certain area of the portion where the uneven portion is formed,
The average of the absolute values of the elevations from the highest peak to the fifth peak of the convex portion of the extracted portion and the lowest valley from the lowest valley to the concave portion with respect to the reference height of the elevation of the unevenness And the average of the absolute values of the altitudes. When the ten-point average roughness Rz of the uneven portion is less than the lower limit, the unevenness is too small to secure a sufficient air flow, and the degreasing of organic components such as a binder does not occur smoothly. On the other hand, if the ten-point average roughness Rz of the uneven portion exceeds the upper limit, the unevenness is too large and the molten salt is not sufficiently filled in the gap between the cell frame and the electrolyte plate after the molten salt impregnation, and the sealing function cannot be performed. .

In the molten carbonate fuel cell according to the present invention, the average interval (average interval between local peaks) S between the adjacent peaks in the uneven portion formed on the cell frame surface of the wet seal portion is defined as S. It is preferable that the ten-point average roughness Rz be 10 times or less, that is, S / Rz ≦ 10 (see FIGS. 7 and 8). The average interval S between the local peaks is an average of the intervals between the peaks of a large number of local peaks obtained by extracting a certain area of the portion where the uneven portion is formed, obtaining the interval between adjacent convex peaks in the extracted portion. It is represented by The average distance S between the peaks of the convex portions is 10-point average roughness R
If it exceeds 10 times z, the pitch of the unevenness is too large and the gap is eliminated due to the deformation of the holding material at the time of degreasing and firing,
Sufficient air circulation is not ensured, and degreasing of organic components such as a binder does not occur smoothly.

[0010] Also, in the molten carbonate fuel cell of the present invention, the surface of the cell frame uneven parts are formed, it is possible to apply a coating layer made of corrosion-resistant material such as aluminum. When a corrosion-resistant coating is applied after the cell frame surface is uneven, not only corrosion of the cell frame etc. after battery start-up is prevented, but also the gas permeability and sealing property of the wet seal part without changing the shape of the unevenness etc. Can be appropriately controlled. The corrosion-resistant coating is, for example, ion plating, CVD, or the like.
(Chemical vapor deposition), aluminum painting, etc.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications. . 1 to 4 show a molten carbonate fuel cell suitable for degreasing a holding material sheet and an electrolyte sheet according to an embodiment of the present invention. As shown in FIG. 1, at the time of assembling a unit cell, a ceramic powder for holding an electrolyte and an organic material are held between two electrodes 10 and 12 of a fuel electrode (anode) 10 and an air electrode (cathode) 12. A holding material sheet 14 including a binder and the like, and an electrolyte sheet 16 including a carbonate serving as an electrolyte and an organic binder are stacked and arranged. The electrodes 10 and 12 are porous and made of, for example, nickel, a nickel alloy, or the like. As the organic binder, for example, polyvinyl butyral (PVB) or the like is used. The organic components other than the binder include a dispersant, a plasticizer, and the like.

A holding material sheet 1 sandwiched between electrodes 10 and 12
The laminate of the electrolyte sheet 4 and the electrolyte sheet 16 has a concave portion for accommodating an electrode on the inner surface, and has a plurality of gas channels 18 in the concave portion.
The peripheral portion of the cell frame 26 is in contact with the stacked body of the holding material sheet 14 and the electrolyte sheet 16. The cell frame 26 is made of, for example, stainless steel (SUS), nickel, a nickel alloy, or the like. In addition, the cell frame is manufactured by plate combination welding, and stainless steel (S
In some cases, a corrugated sheet made of US, nickel, nickel alloy, or the like is used. FIG. 2 is an enlarged view of a portion surrounded by a chain line ellipse in FIG. 1. As shown in FIGS. 1 and 2, the cell frame 2 between the cell frame 26 and the holding material sheet 14 is enlarged.
An uneven portion 28 is formed on the six surfaces. As a processing method of the uneven portion 28, for example, sand blasting, laser processing, etching, sanding, or the like can be used.

The assembled cell is heated to about 100 ° C. in 0.5 to 10 hours, and is heated to about 450 ° C. in 15 to 240 hours.
The temperature is raised over time, and the organic binder and the like contained in the holding material sheet 14 and the electrolyte sheet 16 are degreased. At this time, as shown in FIGS. 1 and 2, sufficient air is supplied from the gas flow path 18 to the gaps between the uneven portions 28 formed on the surface of the cell frame 26 via the porous electrodes 10 and 12,
Oxygen required for smooth combustion such as an organic binder contained in the holding material sheet 14 and the electrolyte sheet 16 is supplied to the gap with the cell frame 26. As described above, since the flow of the air is performed in the path of the gas flow path → the electrode (porous body) → the gap of the wet seal portion → the outside of the battery, a sufficient oxygen amount can be secured. In the holding material sheet 14, the organic binder and the like are removed by burning, leaving only ceramics, and a porous body of ceramics is formed. In the electrolyte sheet 16,
The organic binder and the like are removed by burning, leaving only the carbonate which becomes the electrolyte. Further, the holding material sheet 14, the electrolyte sheet 1
The sheet 6 has a certain degree of plasticity, and its sheet shape is slightly deformed by softening due to temperature rise and pressing from above and below the cell frame 26.

Thereafter, the temperature is further increased to about 650 ° C. by 10 to 15 hours.
The temperature was raised over 0 hours to melt the carbonate, and the molten carbonate was impregnated into the holding material made of the ceramic porous body.
As shown in (1), an electrolyte plate 30 is formed. FIG. 4 is an enlarged view of a portion surrounded by a chain line ellipse in FIG. 3, and after impregnation with the molten salt, as shown in FIGS.
The molten carbonate 32 is formed in the gap between the uneven portion 28 and the electrolyte plate 30.
Is filled to form the wet seal portion 34. As described above, when the battery is operated after the impregnation with the molten salt, the original gas sealing property is ensured by the wetting of the molten salt. During the battery operation, fuel gas (H ₂ , CO _2, etc.) is supplied to the gas flow path 18 on the fuel electrode (anode) 10 side, and the oxidant gas is supplied to the gas flow path 18 on the air electrode (cathode) 12 side. (Air, CO ₂
) Is supplied to carry out the reaction.

As described above, oxygen is supplied as much as possible to the wet seal portion where the supply of oxygen is insufficient at the time of degreasing organic components such as a binder after assembling the battery, so that the binder and the like can be burned smoothly. And the like to prevent incomplete degreasing and shorten the degreasing time. Specifically, by providing irregularities on the cell frame surface of the wet seal portion, the flow of air in the wet seal portion is ensured at the time of degreasing and firing, and the molten salt is filled between the molten salt impregnation and the electrolyte plate. Thereby, the function of the wet seal is sufficiently ensured. If the irregularities are too small, sufficient air circulation cannot be ensured, and if the irregularities are too large, the gap between the cell frame and the electrolyte plate is filled with the electrolyte (molten salt) even after impregnation with the molten salt. ), The gas leaks out of the battery. For example, as shown in FIG. 5, when the unevenness of the uneven portion 38 formed on the surface of the cell frame 36 is too small, the cell frame 36 and the holding material sheet 1
4, there is no sufficient gap, and no air is circulated, so that degreasing and firing of a binder or the like does not occur smoothly. Also,
For example, as shown in FIG. 6, when the unevenness of the uneven portion 42 formed on the surface of the cell frame 40 is too large, the molten carbonate 32 is not sufficiently filled in the gap between the unevenness with the electrolyte plate 30 even after the molten salt impregnation. , The sealing function cannot be performed, and gas leakage to the outside of the battery may occur. For these reasons, it is important to optimally control these irregularities.

Therefore, as shown in FIG. 7, the ten-point average roughness R of the uneven portion 46 formed on the surface of the cell frame 44 is obtained.
It is preferable that z is 3 to 150 μm, preferably 3 to 100 μm, particularly preferably 10 to 50 μm. When the ten-point average roughness Rz of the uneven portion is less than the lower limit, the unevenness is too small to secure a sufficient air flow, and the degreasing of organic components such as a binder does not occur smoothly. On the other hand, when the ten-point average roughness Rz of the irregularities exceeds the upper limit, the irregularities are too large and the molten salt is not sufficiently filled in the gap between the cell frame and the electrolyte plate after the molten salt impregnation, and the sealing function cannot be performed. .
As shown in FIGS. 7 and 8, the average interval S between adjacent convex peaks (the average distance between local peaks) in the concave / convex portion 46 formed on the surface of the cell frame 44 is set to a ten-point average roughness Rz.
10 or less, that is, S / Rz ≦ 10. The average distance S between the peaks of the convex portions is the ten-point average roughness Rz.
If it exceeds 10 times, the pitch of the unevenness is too large and the gap is lost due to the deformation of the holding material at the time of degreasing and firing, sufficient air circulation is not ensured, and the degreasing of organic components such as a binder occurs smoothly. Absent. Average distance S between local peaks
Is the index indicating the size of the unevenness, and the unevenness becomes smooth when S / Rz is large, and is similar to the case where the unevenness is substantially absent due to deformation of the holding material or the like. Therefore, the gap between the holding material and the frame material disappears.

As shown in FIG. 9, when the entire cell frame is viewed from the bottom surface, the unevenness 50 formed on the surface of the cell frame 48 starts from the portion in contact with the electrode inside the battery. It is necessary that a hole or a groove penetrates outside. For this purpose, the irregularities must be randomly formed or, as an example, have a groove shape extending from the inside to the outside like a radial shape shown in FIG. In addition, if the unevenness leads from the inside to the outside,
The shape and the like are not limited at all. If the irregularities do not pass from the part in contact with the electrode inside the battery to the outside of the battery,
Air circulation is not ensured, and degreasing of organic components such as a binder does not occur smoothly. Further, it is preferable that the cross-sectional area ratio between the convex portion and the concave portion in the concave / convex portion formed on the cell frame surface is in the range of 2: 8 to 8: 2. If the ratio of the convex portions is too large in the cross-sectional area ratio of the concave and convex portions, the gap between the cell frame and the holding material is reduced, sufficient air flow is not secured, and degreasing of organic components such as a binder does not occur smoothly. . On the other hand, if the ratio of the concave portion in the cross-sectional area ratio of the concave and convex portions is too large, the molten salt is not sufficiently filled in the gap between the cell frame and the electrolyte plate after the molten salt impregnation, and the sealing function cannot be performed or is maintained. Since the gap becomes too small due to the deformation of the material, the flow of air is not secured, and the degreasing of organic components such as a binder does not occur smoothly. As described above, when the ratio of the convex portions is too large, air does not sufficiently flow because there are few concave portions serving as gaps. Conversely, when the ratio is too small, the concave portions serving as gaps are too large and the molten salt is filled. However, a problem such as fuel leakage occurs even after the battery is started. FIG. 10 shows that the sectional area ratio between the convex portion and the concave portion is 8%.
/ 2 is shown as a bad example (inappropriate example), and FIG.
In the cell frame 52 having the slit-shaped concave portion 54 as shown in FIG.

[0018]

Embodiments of the present invention will be described below. Example 1 A surface of a cell frame material in a wet seal portion was sanded to obtain a ten-point average roughness Rz of 3 μm, 10 μm, 30 μm, 5 μm.
After making 0μm, 100μm, 150μm, electrode (1
00 cm ² ), a unit cell was assembled together with the holding material sheet, the electrolyte sheet and the like. At this time, the file was sanded so that the grooves became radial and passed from the inside to the outside. In addition,
As a comparative example, a unit cell was similarly assembled for a cell frame material whose surface was not sanded. Next, in the same manner as when the fuel cell was started, the temperature was raised to 100 ° C. in 1 hour, and the temperature was raised to 450 ° C. in 120 hours, followed by degreasing and firing.
Further, the temperature was raised to 650 ° C. over 40 hours to impregnate the molten salt. Then, 10 helium gas was introduced into the battery.
The gas leak was checked by injecting the pressure up to a pressure of 00 mm H ₂ O and sealing the air, and measuring the pressure inside the battery after 2 hours. Table 1 shows the results.

Example 2 As in Example 1, after the surface of the cell frame material was sanded, a fuel cell was assembled. In the next battery startup process,
15 minutes of heating and degreasing firing from 100 ° C to 450 ° C
It went in time. Other conditions are the same as in the first embodiment. Thereafter, as in Example 1, helium gas was injected into the battery up to a pressure of 1000 mmH ₂ O, and the battery was sealed. After two hours, the pressure in the battery was measured to determine the gas leak amount. Table 2 shows the results.

[0020]

[Table 1]

[0021]

[Table 2]

According to Table 2, the ten-point average roughness Rz is 3 to 150.
For [mu] m, the He gas was injected at a pressure of 1000MmH ₂ O effect is observed from (leakage to zero pressure in the sanding without) the remaining had ₂ O or more 200mmH even after 2 hours. When Rz is 3 to 100 μm, the residual pressure is 680 mmH _2.
O above, Rz is higher is more effective and the residual pressure 850MmH ₂ O or more in 10 to 50 [mu] m. That is, as can be seen from Tables 1 and 2, when degreasing and firing of an organic binder or the like is performed over a long time, gas leak hardly occurs even in a cell frame material without sanding, but when degreasing and firing time is short, In the case of the cell frame material without sanding, the process proceeds to the step of impregnating the molten salt with insufficient degreasing of the organic binder and the like, so that there is nowhere to go for the molten salt, and the electrolyte plate is damaged, and gas leakage occurs. In addition, the irregularities of the radial grooves have a ten-point average roughness Rz of 3 to 150 μm, particularly 3 to 150 μm.
In the case of 100 μm, after the molten salt impregnation, the gap between the electrolyte plate and the cell frame was filled with the molten salt, and it was found that the function of wet sealing was secured. Therefore,
Rasp the surface of the cell frame material of the wet seal portion, and the ten-point average roughness Rz of the irregularities is 3 to 150 μm,
Preferably, by setting the thickness to 3 to 100 μm, sufficient oxygen is supplied to a wet seal portion where the supply of oxygen is insufficient during degreasing of a binder or the like, thereby preventing incomplete degreasing of the binder or the like and shortening the degreasing time. And
In addition, during the operation of the battery after the impregnation of the molten salt, the original sealing property can be secured by the wetting by the molten salt.

[0023]

As described above, the present invention has the following effects. (1) At the wet seal part of the molten carbonate fuel cell, the cell frame surface is
Irregularities penetrating from the contacting part to the outside of the battery are provided, air flow is secured during degreasing and firing of the electrolyte plate, and after impregnation with the molten salt, the molten salt is filled between the electrolyte plate and the structure with a wet seal function By supplying sufficient oxygen to the wet seal portion where the supply of oxygen is insufficient at the time of degreasing the organic binder, etc., it is possible to prevent incomplete degreasing of the organic binder, etc., to shorten the degreasing time, and to melt During the operation of the battery after the salt impregnation, the original sealing property can be ensured due to the wetting by the molten salt, and gas leakage to the outside of the battery does not occur. (2) Since the molten salt does not proceed to the impregnation step of the molten salt without sufficient degreasing of the organic binder or the like, the molten salt that has nowhere to go does not damage the electrolyte plate of the wet seal portion, and does not cause gas leakage or battery. There is no decrease in performance. (3) By controlling the unevenness of the cell frame surface in the wet seal portion to an appropriate size, shape, and the like, sufficient air flow is ensured in the gaps of the unevenness, and the degreasing of the organic binder and the like is smoothly performed. After the impregnation of the molten salt, the gap between the irregularities is sufficiently filled with the molten salt, and the function of the wet seal can be secured. (4) When a coating layer made of a corrosion-resistant material such as aluminum is applied to the surface of the cell frame on which the uneven portions are formed, in addition to the effect that the gas permeability and sealing property of the wet seal portion can be appropriately controlled, Corrosion of the cell frame and the like after the start of the battery can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic partial cross-sectional configuration diagram showing a molten carbonate fuel cell suitable for degreasing a holding material sheet and an electrolyte sheet according to an embodiment of the present invention during cell assembly and degreasing firing.

FIG. 2 is an enlarged partial cross-sectional configuration diagram illustrating a portion surrounded by a chain line ellipse in FIG. 1;

FIG. 3 is a schematic partial cross-sectional configuration diagram showing a state of forming an electrolyte plate and generating power of a molten carbonate fuel cell suitable for degreasing a holding material sheet and an electrolyte sheet according to an embodiment of the present invention.

FIG. 4 is an enlarged partial cross-sectional configuration diagram illustrating a portion surrounded by a chain line ellipse in FIG. 3;

FIG. 5 is an enlarged partial cross-sectional configuration diagram showing an example of a problem in a molten carbonate fuel cell in which an uneven portion is formed on a cell frame surface of a wet seal portion.

FIG. 6 is an enlarged partial cross-sectional configuration diagram showing another example of a defect in a molten carbonate fuel cell in which an uneven portion is formed on a cell frame surface of a wet seal portion.

FIG. 7 is a schematic partial cross-sectional configuration diagram for explaining a ten-point average roughness Rz of unevenness in an uneven portion formed on a cell frame surface of a wet seal portion.

FIG. 8 is a schematic partial cross-sectional configuration diagram for explaining an average interval (average interval between local peaks) S between convex peaks in a concave / convex portion formed on a cell frame surface of a wet seal portion.

FIG. 9 is a schematic bottom configuration diagram for explaining the directionality of the unevenness in the uneven portion formed on the cell frame surface of the wet seal portion.

FIG. 10 is a schematic partial cross-sectional configuration diagram for explaining an example in which the cross-sectional area ratio between the convex portion and the concave portion in the concave-convex portion formed on the cell frame surface of the wet seal portion is poor (inappropriate example).

FIG. 11 is a schematic cross-sectional configuration diagram showing a process of forming an electrolyte plate in a conventional molten carbonate fuel cell.

FIG. 12 is a schematic partial cross-sectional configuration diagram showing a state of a conventional molten carbonate fuel cell at the time of binder degreasing.

[Explanation of symbols]

10, 12 electrode 14 holding material sheet 16 electrolyte sheet 18 gas flow path 20, 26, 36, 40, 44, 48, 52 cell frame 22, 30 electrolyte plate 24, 34 wet seal portion 28, 38, 42, 46, 50 Uneven portion 32 molten carbonate 54 slit-shaped recess

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-39770 (JP, A) JP-A-6-342662 (JP, A) JP-A-62-71171 (JP, A) JP-A-2- 162655 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01M 8/00-8/24

Claims (4)

(57) [Claims] 1. A cell frame comprising two cell frames having an inner surface having a concave portion for accommodating an electrode and having a plurality of gas flow paths in the concave portion, wherein the two electrode plates and an electrolyte plate between the electrodes are sandwiched. In a molten carbonate fuel cell in which a wet seal portion is formed by sandwiching an electrolyte plate at the peripheral edge of the cell, the surface of the cell frame of the wet seal portion is required to degrease and sinter the holding material sheet and the electrolyte sheet. The air is circulated, and the molten carbonate as the electrolyte is impregnated in the degreased and baked holding material to form an electrolyte plate, and the molten carbonate is sufficiently filled to exhibit the function of a wet seal. Penetrated out of the battery from the part in contact with the electrode inside the battery
Molten carbonate fuel cell which is suitable for degreasing of the holding sheet, the electrolyte sheet, wherein a concave-convex portion in the form is formed. 2. The ten-point average roughness Rz of the uneven portion formed on the cell frame surface of the wet seal portion is 3 to 150 μm.
A molten carbonate fuel cell suitable for degreasing the holding material sheet / electrolyte sheet according to claim 1. 3. The holding material sheet according to claim 2, wherein the average distance S between adjacent peaks of the convex portions in the concave / convex portions formed on the cell frame surface of the wet seal portion is 10 times or less the ten-point average roughness Rz.・ Molten carbonate fuel cell suitable for degreasing electrolyte sheets . 4. The molten carbon dioxide suitable for degreasing a holding material sheet and an electrolyte sheet according to claim 1 , wherein a coating layer made of a corrosion-resistant material is applied to the surface of the cell frame on which the uneven portions are formed. Salt type fuel cell.