JP2008305671A - Gas seal structure, gas seal, and gas sealing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas seal structure in which both of an electrical connection and a gas seal can be realized simultaneously in an operation for a long period which includes a thermal cycle such as an operation shutdown and provide a gas seal and a gas sealing method. <P>SOLUTION: The gas seal structure is composed of a seal member 3 which has a closed shape with conductivity is provided with an inner circumferential side engagement portion 19a and an outer circumferential engagement portion 19b and at least a region 3a of which has elasticity, a sealing object 1 in which a closed shape concave portion 4 is formed and another sealing object 2, and a locking portion 7 to be inserted into the concave portion 4. The locking portions 7a, 7b are deformed in the concave portion 4a of the sealing object 1 and in the concave portion 4b of another sealing object 2 and the locking portion 7 and the concave portion 4 are engaged. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gas seal for SOFC (Solid Oxide Fuel Cell).

  In recent years, interest in SOFCs using oxygen ion conductors is increasing. In particular, from the viewpoint of effective use of energy, solid fuel cells are not subject to the restrictions of Carnot efficiency, so they have inherently high energy conversion efficiency and have excellent features such as better environmental conservation. (Non-Patent Document 1).

  In particular, since a flat cell has a high output density, it is expected that a high-performance fuel cell system can be realized.

In general, a stack in which a plurality of flat plate cells are stacked is assembled as one unit. In this stack, as a method of electrically connecting cells and supplying gas to each cell, there are an external manifold type in which the gas supply part is separated from the electrical connection part, and an integrated internal manifold type. . The internal manifold type stack can keep the empty space low, which is advantageous for realizing a cell stack with high power density. Non-Patent Document 2 discloses a gas seal of an internal manifold type cell stack.
Hiroaki Tagawa “Solid Oxide Fuel Cell and Global Environment”, published by Agne Jofusha, 1998 LGJDe Haart and ICVinke, in the proceeding of the Solid Oxide Fuel Cell VII (SOFC VII), (2001), p.111-119.published by The Electrochemical Society Inc.

  However, in the case of the internal manifold type, since the gas supply part and the electrical connection part cannot be compressed independently, it is extremely high to compress the stack in the connection direction and perform both the electrical connection and the gas seal at the same time. Dimensional accuracy is required and is actually very difficult. In addition, the cell itself and the current collector in contact with the cell are exposed to a high temperature for a long time, so that they are burned out, and the dimensions of these parts are slightly reduced. For this reason, it is more difficult to perform both electrical connection and gas sealing simultaneously for a long time.

  Further, as the temperature changes due to the operation stop of the fuel cell system, the cell is slightly deformed due to the difference in the thermal expansion coefficient of the ceramics constituting the cell. Further, a gap is likely to occur in the gas seal portion due to the difference in thermal expansion coefficient between the cell made of ceramics and the metal interconnector adjacent thereto. In order to cope with such deformation, the gas seal needs to have a certain degree of flexibility. For this, there is a method using a glass seal, but glass which is liquid is liable to cause reaction deterioration with ceramics at a high temperature, and crystallization occurs, making it difficult to perform a stable gas seal over a long period of time.

  In order to solve this, it is necessary for the gas seal portion to be deformed as the part size is reduced and to keep the sealing performance. Thereby, the force which compresses a stack is mainly applied to the electrode surface of a cell, can maintain an electrical connection, and can maintain gas-sealing property in spite of weak compression force.

  On the other hand, in the case of the external manifold type, the gas supply part and the cell part can be compressed independently, but both are connected by gas piping. For this reason, since there is a reduction in the dimension in the stacking direction due to the burning of the cell portion, stress is applied to the gas piping portion. As a result, there is a concern that an asymmetric stress is applied to the cell and the electrical connection is hindered. Accordingly, even in the case of the external manifold type, it is necessary that the gas seal portion be deformed as the dimensions of the parts are reduced.

  In addition, since stress accompanied by elastic deformation is easily relaxed at high temperatures, the effect of connection and sealing depending on elasticity is reduced by long-term use.

  Accordingly, the present invention provides a gas seal structure, a gas seal, and a gas seal method capable of simultaneously realizing both electrical connection and gas seal in a long-time operation including a thermal cycle such as operation stop. With the goal.

  In order to achieve the above object, the gas seal structure of the present invention is a solid electrolyte fuel cell and a gas seal structure in a gas supply path to the solid oxide fuel cell. A seal member in which a meshing portion is formed, a seal member having at least a region between the meshing portions having flexibility, a recessed portion having a closed shape formed at a position corresponding to the meshing portion, and other parts A part to be sealed and an engaging part to be inserted into the concave part, the surface on which the concave part of the part to be sealed is formed, and the surface on which the concave part of the other part to be sealed are formed are opposed to each other, Each engagement portion of the seal member disposed between these surfaces is inserted into each recess, so that either the recess or the engagement portion is deformed, and the recess and the engagement portion are engaged with each other. .

  As described above, the seal member of the present invention has conductivity, and a plurality of meshing portions are provided, and a region between the meshing portions has flexibility. For this reason, the seal structure of the present invention can follow the displacement even if the part to be sealed is displaced, and can maintain the seal characteristics.

  Further, the seal member and the seal target component of the present invention are engaged with each other without a gap by the engagement portion being inserted into the recess of the seal target component, whereby one of the engagement portion or the recess is deformed. For this reason, the seal structure of the present invention can securely hold the seal member and ensure electrical connection between the two.

  In the gas seal structure of the present invention, the engaging portion is plastically deformed, and the shape in the concave portion is set to the resistance when the engaging portion is pulled out from the concave portion and the resistance when the engaging portion is inserted into the concave portion. It may be a shape that makes the comparison larger.

  In addition, the gas seal structure of the present invention may have a tapered shape in which the cross-sectional shape of the recess extends from the entrance side of the recess toward the bottom of the recess.

  Moreover, the gas seal structure of this invention may be formed with an edge that enters the tip of the engaging portion at the bottom of the recess.

  Moreover, the gas seal structure of this invention may have an elastic member which presses an engaging part on the inner wall face of a recessed part.

  In the gas seal structure of the present invention, an edge may be formed at the tip of the engaging portion, and the bottom of the recess may be plastically deformed by the entry of the edge.

  In the gas seal structure of the present invention, the sealing member may be an annular metal foil.

  The gas seal of the present invention is a gas seal in a solid oxide fuel cell and a gas supply path to the solid oxide fuel cell, and has a closed shape and conductivity, and a plurality of meshing portions are formed. At least the region between the meshing portions has flexibility.

  The gas sealing method of the present invention is a solid electrolyte fuel cell and a gas sealing method in a gas supply path to the solid oxide fuel cell. In the gas sealing method, the gas sealing method has a closed shape and has conductivity, and a plurality of meshing portions are formed. A seal member having at least a region between the meshing portions having flexibility, a seal target component formed with a recessed portion having a closed shape formed at a position corresponding to the mesh portion, and other seal target components, and a recess An engaging portion to be inserted is prepared, and a surface on which a concave portion of a part to be sealed is formed and a surface on which a concave part of another part to be sealed are formed are opposed to each other, and a seal is provided between these surfaces. A member is disposed, and each engagement portion of the seal member is inserted into each recess to deform one of the recess and the engagement portion, and the recess and the engagement portion are engaged with each other.

  According to the seal structure of the present invention, since the seal member can follow the displacement even when the seal target component is displaced, the seal characteristics can be maintained.

  According to the seal structure of the present invention, the conductive seal member and the part to be sealed are deformed in one of the engaging portion or the recessed portion to form a meshing portion. For this reason, the seal structure of the present invention can securely hold the seal member and ensure electrical connection between the two.

  FIG. 1 is a schematic sectional side view of the gas seal structure of the present invention. FIG. 2 is a schematic perspective view of the sealing member of the present invention. In FIG. 1, the left side corresponds to the inner peripheral side of the seal member. In the following description, the subscript a indicates the inner peripheral side, and the subscript b indicates the outer peripheral side.

  The gas seal structure of the present invention has an annular shape and is electrically conductive, and has an inner peripheral side engagement portion 19a on the inner peripheral portion side and an outer peripheral engagement portion 19b on the outer peripheral portion. The seal member 3 having a flexible region between the mating portion 19a and the outer peripheral meshing portion 19b, a set of seal target components 1 and 2 sealed by the seal member 3, and the seal target components 1 and 2 And an engaging portion 7 to be inserted into the recess 4.

  As described above, the seal member 3 has an annular shape, and an inner peripheral side engagement portion 19a is provided on the inner peripheral portion, and an outer peripheral engagement portion 19b is provided on the outer peripheral portion. The seal member 3 is made of a metal foil. The material of the seal member 3 is preferably a chromium-based heat-resistant alloy containing aluminum or silicon such as ZMG232 in addition to the Croper 22. Since the seal member 3 is made of a metal foil, it has conductivity and flexibility.

  The engaging portion 7 is made of a material that is plastically deformed. For example, a chromium-based heat-resistant alloy containing aluminum or silicon, such as Croper 22 and ZMG 232, is preferably used in the same manner as the seal member 3. The engaging portion 7 may be integrated with the seal member 3. When the plastic deformation of the engaging portion 7 is relatively large, the engaging portion 7 may be separated from the seal member 3, and in this case, it is preferable to use a noble metal such as silver or palladium. In addition, the engaging portion 7 may have a distal end portion made of a soft material so as to be easily deformed.

  In the present invention, the engagement portion 7 is a member that pushes the seal member 3 into the recess 4, and the seal member 3 and the recess 4 are engaged with each other when either the recess 4 or the engagement portion 7 is deformed. It has a function to make it.

  A recess 4a is formed on the inner peripheral surface 9a of the part 1 to be sealed. The cross-sectional shape of the recess 4a is a tapered shape that spreads from the inlet 5a toward the bottom 6a. A concave portion 4b having the same shape is also formed on the outer peripheral surface 9b of the part 2 to be sealed.

  Next, the sealing method of the present invention will be described with reference to FIGS. 1 (a) and 1 (b).

  First, the surface 9a side of the seal target component 1 and the surface 9b side of the seal target component 2 are arranged to face each other. By arranging in this way, the pressing surface 10b of the sealing target component 2 faces the surface 9a of the sealing target component 1, and the pressing surface 10a of the sealing target component 1 faces the surface 9b of the sealing target component 2. Become. The seal member 3 is disposed between these surfaces 9a and 9b. The engaging portion 7a is disposed at a position corresponding to the recessed portion 4a with the seal member 3 interposed therebetween, and the engaging portion 7b is disposed at a position corresponding to the recessed portion 4b with the seal member 3 interposed therebetween.

  Further, spacers 8 are sandwiched between the engaging portion 7a and the pressing surface 10b and between the engaging portion 7b and the pressing surface 10a, respectively. The spacer 8 is used only when the sealing member 3 is engaged with the recess 4 and is removed after the sealing.

  In the above state, as shown in FIG. 1A, a load is applied from the back surface 11 side of the part to be sealed 1. Thereby, as shown in FIG.1 (b), the engaging part 7a is crushed and plastically deformed in the recessed part 4a. Similarly, the engaging portion 7b is also crushed and plastically deformed in the recess 4b. Thus, the engaging part 7 is crushed and plastically deformed inside the concave part 4, so that the engaging part 7 is deformed so as to follow the internal shape of the concave part 4 and meshes with no gap. That is, the cross-sectional shape of the engaging portion 7 is a tapered shape that spreads from the inlet 5 side toward the bottom portion 6. If it does so, even if it tries to pull out the engaging part 7 from the recessed part 4, since it will be hooked in the part of the inlet 5, it will become difficult to pull out.

  That is, according to the seal structure of the present invention, before the engaging portion 7 is plastically deformed, the engaging portion 7 can be inserted into the recess 4 without receiving any resistance from the inlet 5. When the engagement portion 7 is to be pulled out of the recess 4, the engagement portion 7 that has spread due to plastic deformation receives the resistance of the inlet 5, so that the engagement is not easily released. For this reason, the seal structure of the present invention can securely hold the seal member 3 and also ensure electrical connection between them.

  In addition, as shown in FIG. 1 (b), the region 3a between the inner peripheral side engaging portion 19a and the outer peripheral side engaging portion 19b of the seal member 3 after being sealed is provided with some clearance. It has become. Since the sealing member 3 of the present invention is flexible in the material itself and has a space in the region 3a, even if the parts 1 and 2 to be sealed are displaced in the directions of arrows a and b in the figure, the displacement follows. It is possible to maintain the sealing characteristics.

  Because of such a structure, the gas seal structure of the present invention is a component in which the parts to be sealed 1 and 2 are operated for a long time including a heat cycle and are required to be electrically connected to each other. Both electrical connections can be ensured while maintaining the sealing characteristics. In particular, when the present invention is used as a gas seal for SOFC, the sealing properties are maintained even when the size of the cell or current collector is reduced, the expansion or contraction due to the thermal cycle occurs, and the electrical connection between the two is ensured. This is advantageous in that

  The shape of the seal member 3 is not limited to an annular shape as shown in FIG. That is, any shape such as a square or a triangle may be used as long as it has a closed shape and has a function of separating (sealing) gas between a hollow portion and an outer peripheral portion thereof.

  Moreover, although the sealing target components 1 and 2 shown in FIG. 1 are provided with the recesses 4a and 4b separately on the inner peripheral side and the outer peripheral side in the radial direction, the configuration shown in FIG. The gas seal structure of FIG. 3 is provided with a recess 4 on the same radius, and the seal member 3 is bent and used. In this case, the insertion of the engaging portion 4 is completed only by applying a weight to one place. Therefore, only one spacer 8 is required, and the process required for sealing can be shortened. Further, this configuration has an advantage that the area occupied by the seal member 3 can be minimized.

  In the configuration shown in FIG. 3, the seal member 3 is provided with a base 12 made of a material harder than the engaging portion 7 and hard to be deformed in the portion where the engaging portion 7 is provided as shown in FIG. You may make it give flexibility. By providing the pedestal 12, it is easy to apply a load to the engaging portion 7, and plastic deformation can be promoted. Further, it is sufficient that a part of the metal foil is flexible. Particularly, a portion near the engaging portion is stressed and easily damaged, and therefore it is preferable to use it in combination with a thick plate such as the base 12. The pedestal 12 may be provided separately from the seal member 3 or may be integrated.

  In addition, the engaging portion 7 may be made of a metal that is easily plastically deformed only at the tip portion, and the side pressed by the spacer 8 may be made of an alloy having high heat resistance such as iron-chromium alloy. With such a structure, it is not necessary to increase the dimensional accuracy of each part.

  Alternatively, as shown in FIG. 5, an edge 14 may be provided on the bottom 6 of the recess 4 and the engaging portion 7 may bite into the edge 14. Thereby, the engagement effect can be enhanced. Further, if the edge is sharp such as having a part in this way, the concentrated stress acts only on the corner part, and this part is locally deformed, which advantageously increases the sealing performance. Furthermore, the same effect can be expected by increasing the dimensionality and reducing the meshing clearance. In the configuration of FIG. 5, the engaging portion 7 may be provided separately from the seal member 3 or may be integrated.

  On the contrary, as shown in FIG. 6, an edge 15 may be provided on the engagement portion 7 side and a plastic deformation portion 16 may be provided on the bottom portion 6 of the recess 4. Further, in the configuration having the edges 14 and 15, the engaging portion 7 may be provided on the pedestal 17 as shown in FIG. 6 in order to promote biting of the edges 14 and 15. In the configuration of FIG. 6, the engaging portion 7 and the pedestal 17 may be provided separately from the seal member 3 or may be integrated.

  Further, the gas seal structure of the present invention can be combined with the elastic member 18 as shown in FIG. In the example shown in FIG. 7, the elastic member 18 is inserted into the recess 4 together with the engagement portion 19 when the engagement portion 19 of the seal member 3 is inserted into the recess 4. The meshing portion 19 passes through the inlet 5 while elastically deforming without being plastically deformed. After passing through the inlet 5, the meshing portion 19 is pressed against the inner wall surface of the recess 4 by the pressing force of the elastic member 18 and is plastically deformed. In the case of the configuration shown in FIG. 7, since the elastic member 18 continues to press the engagement portion 19 plastically deformed in the recess 4 against the inner wall surface of the recess 4, the engagement can be strengthened.

  Further, the present invention may have a gas seal structure in which the seal member 3 is not plastically deformed, the recess 4 is temporarily elastically deformed during insertion, the inlet 5 is opened slightly, and the seal member 3 is inserted. After insertion, there is almost no elastic deformation, so no stress is applied, and deformation due to stress relaxation during operation can be avoided. However, even if a force that disengages the engagement portion is temporarily generated (due to a thermal cycle or the like), the stress relaxation hardly proceeds.

  In addition, according to the present invention, a glass sealing material can be put in the engaging portion.

  Moreover, although this invention illustrated as an example the structure which has two seal parts of the inner peripheral side engaging part 19a and the outer peripheral side engaging part 19b, it is not limited to this, It has three or more seal parts It may be.

Examples of the present invention will be described below. Of course, the present invention is not limited to the following examples.
Example 1
On a porous NiO—YSZ (0.89ZrO ₂ -0.08Y ₂ O ₃ ) fuel electrode substrate having a thickness of 1.5 mm, a dense Sc ₂ O ₃ , Al ₂ O ₃ added zirconia SASZ (0.89ZrO ₂ -0.10Sc ₂ O ₃ -0.01Al ₂ O ₃ ) An electrolyte thin film, on which an air electrode made of LNF (LaNi _0.6 Fe _0.4 O ₃ ) is provided (diameter supported) 6 cm, the diameter of the air electrode is 5 cm), and in order to supply and electrically connect fuel gas and air to these cells, it is made of iron-chromium alloy (Crofer 22), which is a kind of heat-resistant alloy. It is stacked up and down in a sandwiched form with a single interconnector. This is called a cell stack.

  FIG. 8 is a top perspective view of the fuel cell stack interconnector.

  The interconnector 20 is provided with a cell arrangement portion 24 at the center, and an air supply hole 21, a fuel gas supply hole 22, and a fuel gas recovery hole 23 are arranged around the cell arrangement portion 24.

  A porous nickel mat was sandwiched between the interconnector 20 and the fuel electrode, and a paste of LNF was applied and dried between the air electrode and the interconnector.

  The air is guided from the air supply hole 21 along the interconnector 20 to the center position of each cell and flows radially from the center. The fuel gas supplied from the fuel gas supply hole 22 enters from the end portion of the cell arrangement portion 24 cell, exits from the cell arrangement portion 24 cell end portion, and flows into the fuel gas recovery hole 23. The fuel gas introduction part has a tunnel structure in which metal plates are bonded together.

  The cell stack placed in the electric furnace was heated to an operating temperature of 800 ° C., and gas was supplied in a state where the entire stack was compressed with a force of about 20 kg. In the gas seal structure 30 of the present invention, the gas seal structure 30 of the present invention is provided around each of the air supply hole 21, the fuel gas supply hole 22, and the fuel gas recovery hole 23. A glass seal is used at a contact portion between the periphery of the cell and the interconnector.

  Here, the cross section of the gas seal structure 30 of the present invention is composed of two meshing portions arranged concentrically. As shown in FIG. 1, the cross-section of each meshing portion is such that the engagement portions of the sealing target component 1 and the sealing target component 2 are symmetrical, and the groove that is a concentric recess 4 is as wide as the cross-section is. Is a wide overhang. The width of the recess 4 at the entrance is 2 mm, the width at the bottom 6 is 2.4 mm, and the depth is 2 mm. The cross section of the engaging portion 7 is a square having a height of 4 mm and a width of 1.9 mm, and the tip portion is made of silver over a length of 0.7 mm. These concentric engagement portions 7 are formed on an iron-chromium heat-resistant alloy interconnector concentrically with the center position of the cell, on a torus-shaped inconel foil having an outer diameter of 9 cm and an inner diameter of 7 cm, and a thickness of 0.04 mm. It is arranged at a position of 7.6 cm diameter and a position of diameter 8.4 cm.

  When assembling the cell stack at room temperature, the engaging portion 7 is inserted. At this time, the silver portion at the tip is crushed to fill the groove, and the engaging portion 7 is difficult to dissociate. Here, the temporary spacer 8 was used to push the inner peripheral meshing portion 19a to insert the engaging portion 7 into the recess 4 and then insert the outer peripheral seal of the outer peripheral meshing portion 19b.

  As shown in FIG. 8, there are three places where a gas seal for flowing air and fuel is required in addition to the part for storing the cells. Here, these small-diameter seal portions are fused with a Pyrex glass ring sandwiched therebetween.

  The fuel used was room temperature humidified hydrogen. The total open-circuit voltage of the stack of two cells was as high as about 2.0 V, and it was found that the gas seal was functioning. When a current of 2 amperes was passed, it was found that the voltage was 1.7 V and the electrical junction was sufficient. In this state, the operation was stopped every 100 hours, the temperature was lowered to room temperature, the temperature was raised again, and a heat cycle test was performed in which the same operation was performed. When the operation for 1000 hours was finally performed, the voltage and the open voltage were not changed, but the entire stack was compressed by about 0.2 mm.

As described above, even when the cell itself is compressed by a long-term operation, it has been proved that the gas sealability and the electrical connection characteristic are maintained because the seal portion is deformed correspondingly.
(Example 2)
In Example 1, the gas seal structure was as shown in FIG. That is, the tip of the engaging portion 7 is palladium, and the edge 14 having a triangular cross section is provided on the bottom 6 of the recess 4. The depth and width of the recess 4 were 2 mm, the edge 14 was 0.8 mm in height, and the bottom width was 0.4 mm. A torus-like Inconel foil coating having a thickness of 0.1 mm is brazed with silver. The engaging portion was inserted when the stack was assembled, and the same test as in Example 1 was performed.

The open voltage of this cell stack was 2.0V, and the voltage at a current of 2A was as good as 1.8V. Further, the same thermal cycle test as in Example 1 was performed, and after a total of 1000 hours of operation, the entire stack was also compressed by about 0.2 mm. However, there was no change in voltage and open circuit voltage.
(Example 3)
In Example 3, the gas seal structure was as shown in FIG. That is, the same triangular edge 15 as that of the second embodiment is provided at the tip of the engaging portion 7 made of iron-chromium heat-resistant alloy, and a Pd sheet is silver brazed to the bottom surface of the recess 4 as the plastic deformation portion 16. The engaging portion was inserted when the stack was assembled, and the same test as in Example 1 was performed.

The open voltage of this cell stack was 2.0V, and the voltage at a current of 2A was as good as 1.8V. Also, after 1000 hours of operation, the entire stack was still compressed by about 0.2 mm. However, there was no change in voltage and open circuit voltage.
Example 4
In Example 1, the gas seal structure was as shown in FIG. That is, two seal portions were arranged on the same circumference having a diameter of 7.5 cm, and upper and lower engaging portions were simultaneously inserted using a temporary spacer when the stack was assembled. Further, a seal having the same shape was used for the small-diameter gas seal portion of FIG. That is, on the outer periphery of a gas path having a diameter of 1 cm, a bent torus-shaped metal foil (above-mentioned metal foil) having an inner diameter of 1.5 cm and an outer diameter of 2.0 cm and an engaging part are inserted and attached to the inner part, and the tip is attached. Deformed. Thereafter, the same test as in Example 1 was performed.

The open voltage of this cell stack was 2.1V, and the voltage was as good as 1.9V when the current was 2A. Also, after 1000 hours of operation, the entire stack was still compressed by about 0.2 mm. However, there was no change in voltage and open circuit voltage.
(Example 5)
In Example 4, the gas seal structure was as shown in FIG. That is, the area of the metal foil near the engaging portion was reduced and the engaging portion was extended. The extension is made of an iron-chromium heat-resistant alloy and is as thick as 0.5 mm. The assembly was performed in the same manner as in Example 4, and then the same test as in Example 4 was performed.

The open voltage of this cell stack was 2.2 V, and the voltage at a current of 2 A was as good as 2.0 V. Also, after 1000 hours of operation, the entire stack was still compressed by about 0.2 mm. However, there was no change in voltage and open circuit voltage.
(Example 6)
In Example 1, the gas seal structure was as shown in FIG. That is, the seal member 3 hardly undergoes plastic deformation, and the concave portion 4 is temporarily elastically deformed when inserted, and the inlet 5 is slightly opened to insert the seal member 3. After insertion, there is almost no elastic deformation, so no stress is applied, and deformation due to stress relaxation during operation can be avoided. The engaged portion is an O-ring with a wire diameter of 4 mm and an inner diameter of 7 cm. As the metal foil, a gold foil having a thickness of 0.02 mm is used. In this case, the metal foil is accompanied by plastic deformation at the time of insertion. Similar to the example, the engagement portion was inserted using a temporary spacer, and the same test as in Example 1 was performed.

  The open voltage of this cell stack was 2.0V, and the voltage was as good as 1.9V when the current was 2A. Also, after 1000 hours of operation, the entire stack was still compressed by about 0.2 mm. However, there was no change in voltage and open circuit voltage.

  As described above, in the present invention, there are two interlocking structures that do not lose the sealing property even when exposed to high temperatures for a long time such as with plastic deformation, and these are connected by a flexible metal foil. It was.

  As a result, even when the gap length of the seal portion changes due to a heat cycle or a long-term operation, the gas sealability can be maintained following the change, and the seal member has flexibility, so the manifold is compressed. Since the weight is mainly applied to the electrode portion of the cell, the electrical connection can be maintained.

  This succeeded in obtaining a highly reliable solid oxide fuel cell seal. The present invention greatly contributes to the high reliability of SOFC.

It is a typical sectional side view of the gas seal structure of this invention. It is a typical perspective view of the sealing member of the present invention. FIG. 3 is a schematic side sectional view of a configuration of the gas seal structure of the present invention, in which recesses are formed in the same radius. FIG. 3 is a schematic side sectional view of a gas seal structure of the present invention, in which recesses are formed in the same radius, and the seal member has a pedestal. FIG. 3 is a schematic side sectional view of a configuration in which the edge is provided at the bottom of the recess, which is the gas seal structure of the present invention. It is a gas seal structure of the present invention, and is a typical sectional side view of the composition provided with the edge at the tip part of the engaging part. FIG. 5 is a schematic side cross-sectional view of the structure of the gas seal structure of the present invention in which the engaging portion is inserted by temporarily elastically deforming the inlet of the recess. FIG. 4 is a top perspective view of a fuel cell stack interconnector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Parts to be sealed 3 Seal member 3a Area | region 4 Recessed part 5 Inlet 6 Bottom part 7 Engagement part 8 Spacer 9a, 9b Surface 10a, 10b Press surface 11 Back surface 12 Base 14 Edge 15 Edge 16 Plastic deformation part 17 Base 18 Elastic member 19a Inner peripheral side engagement part 19b Outer peripheral side engagement part 20 Interconnector 21 Air supply hole 22 Fuel gas supply hole 23 Fuel gas recovery hole 24 Cell arrangement part 30 Gas seal structure

Claims (9)

In a gas seal structure in a solid oxide fuel cell and a gas supply path to the solid oxide fuel cell,
A closed member having conductivity in a closed shape, a plurality of meshing portions are formed, and a region between the meshing portions is flexible,
A sealing target component in which a closed concave portion formed at a position corresponding to the engagement portion is formed, and the other sealing target component;
An engaging portion inserted into the recess,
The surface of the sealing target component on which the concave portion is formed and the surface of the other sealing target component on which the concave portion is formed are disposed to face each other, and the sealing member disposed between these surfaces A gas seal structure, wherein each engagement portion is inserted into each recess to deform one of the recess and the engagement portion, and the recess and the engagement portion are engaged with each other.   The engagement portion is plastically deformed, and the shape in the recess makes the resistance when the engagement portion is pulled out from the recess larger than the resistance when the engagement portion is inserted into the recess. The gas seal structure according to claim 1, which has a shape.   The gas seal structure according to claim 2, wherein a cross-sectional shape of the concave portion is a tapered shape that spreads from an inlet side of the concave portion toward a bottom portion of the concave portion.   4. The gas seal structure according to claim 2, wherein an edge for entering the tip of the engaging portion is formed at a bottom portion of the concave portion.   The gas seal structure according to claim 1, further comprising an elastic member that presses the engaging portion against an inner wall surface of the recess.   The gas seal structure according to claim 1, wherein an edge is formed at a tip of the engagement portion, and a bottom portion of the recess is plastically deformed by the entry of the edge.   The gas seal structure according to any one of claims 1 to 6, wherein the seal member is an annular metal foil. A gas seal in a solid oxide fuel cell and a gas supply path to the solid oxide fuel cell,
A gas seal having a closed shape and conductivity, a plurality of meshing portions formed, and at least a region between the meshing portions having flexibility. In a solid oxide fuel cell and a gas sealing method in a gas supply path to the solid oxide fuel cell,
A closed shape that is electrically conductive and has a plurality of meshing portions, and at least a region between the meshing portions is a flexible seal member and a closure formed at a position corresponding to the meshing portion. A sealing target part in which a concave part having a different shape is formed and another sealing target part, and an engaging part to be inserted into the concave part,
The surface of the part to be sealed in which the concave part is formed and the surface of the other part to be sealed in which the concave part is formed are opposed to each other, and the sealing member is disposed between the surfaces.
A gas sealing method in which each of the engaging portions of the seal member is inserted into each of the recessed portions, and either one of the recessed portion or the engaging portion is deformed to engage the recessed portion and the engaging portion.

Images