JP2012182069A - Solid oxide fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid oxide fuel cell ensuring the excellent gas sealing properties of the junction region of a cell body and a segregated separator.SOLUTION: A solid oxide fuel cell comprises a unit cell including a cell body 10 made by laminating a fuel electrode layer, a solid electrolyte layer, and an air electrode layer, and a frame-shaped segregated separator 25 separating a fuel gas passage on the fuel electrode layer side and an air passage on the air electrode layer side. The cell body is joined to the segregated separator via a junction region 40 surrounding an opening 34 of the segregated separator. Each of the outer edge and the inner edge of the junction region has a plane shape of a square with four rounded corners. Thus, the stress which tends to concentrate on each corner of the junction region is relaxed and the area of the junction region increases to improve the gas sealing properties of the segregated separator.

Description

  The present invention is a flat plate type having a structure in which a cell body in which at least a fuel electrode layer, an air electrode layer, and a solid electrolyte layer are laminated, and a separator that separates the fuel gas flow path and the air flow path are integrated. The present invention relates to a solid oxide fuel cell.

  Conventionally, a flat-type solid oxide fuel cell (SOFC) is known. In general, a flat SOFC has a cell body formed by disposing a fuel electrode layer in contact with a fuel gas on one side of a solid electrolyte layer and an air electrode layer in contact with an oxidant gas (air) on the other side. The cell main body is joined to an isolation separator to isolate the fuel gas flow path and the oxidant gas flow path. The isolation separator is made of, for example, a frame-like metal plate, and is integrally joined to the cell main body via a brazing material or the like (joining portion) in a region surrounding the opening and joining. In general, the cell body and the separator are formed in a square planar shape, but the separator is formed extremely thin for weight reduction and the like, and is easily damaged at the joint area with the cell body. The structure which chamfers is proposed (for example, refer patent document 1). In order to secure a good gas sealing property by the isolation separator, it is important to keep the cell body and the isolation separator sufficiently in close contact with each other via a junction (hereinafter also referred to as a junction region).

JP 2006-4678 A

  As described above, the joining area between the cell body and the separator is a square ring surrounded by the outer periphery of the cell body and the inner periphery (opening) of the separator. In general, in a joint region having such a shape, stress tends to concentrate on four corners as compared to a four-side region. When stress is concentrated at each corner of the joining region, the adhesion between the cell body and the separator is not maintained at that portion, which causes a gas leak. In particular, when each corner portion of the cell body is chamfered as disclosed in Patent Document 1, each corner portion of the outer peripheral shape of the joining region is also chamfered, so that each corner portion is joined as compared to the four side portions. The area will be reduced, and it will be more susceptible to stress concentration. As a result, the concentration of stress on each corner of the joining region results in insufficient adhesion between the cell body and the separator and the gas sealing performance is deteriorated. On the other hand, if the opening portion of the isolation separator is made smaller, the area of the joining region increases. In this case, the region that can be exposed to the opening portion of the cell body is restricted, so the power generation area is reduced, which is not preferable. As described above, in the conventional SOFC, it is difficult to improve the gas sealing performance in the joining region between the cell main body and the isolation separator while ensuring good power generation performance.

  The present invention has been made to solve these problems, and provides a solid oxide fuel cell capable of enhancing gas sealing performance in a joining region between a cell body and an isolation separator while maintaining power generation performance. The purpose is to provide.

  In order to solve the above problems, a solid oxide fuel cell according to the present invention includes at least a fuel electrode layer in contact with a fuel gas, an air electrode layer in contact with an oxidant gas, and the fuel electrode disposed on one surface side. And a plate-like cell body on which the solid electrolyte layer having the air electrode disposed on the other surface side is laminated, and an opening that is disposed on one surface side of the cell body and penetrates in the thickness direction. A frame-shaped isolation separator that has at least a part of the fuel electrode layer or the air electrode layer of the cell body exposed from the opening and has a joint for joining the solid electrolyte layer of the cell body; The junction has a planar shape including an outer periphery and an inner periphery, and the outer periphery shape and the inner periphery shape are both planar shapes chamfered at four corners of a rectangle. It is characterized by being

  According to the solid oxide fuel cell of the present invention, when the cell body in which the fuel electrode layer, the air electrode layer, and the solid electrolyte layer are laminated is joined to the isolation separator, the joining region is on the outer peripheral side of the cell body. The outer peripheral shape depends on the inner periphery and the inner peripheral shape depends on the inner peripheral side where the separator separator has an opening, and each corner of the outer peripheral shape and each corner of the inner peripheral shape are chamfered. Has been. Therefore, when the cell body and the separator separator are joined in the joining region, the stress that tends to concentrate on the corners can be relieved, and the gas sealability is improved while maintaining sufficient adhesion between the cell body and the separator separator. Can do. In addition, when chamfering only each corner of the cell body as in the conventional structure, the bonding area is reduced at each corner of the bonding region. Since it is chamfered, a reduction in the bonding area can be avoided. Furthermore, since the bonding area is ensured, it is not necessary to reduce the opening of the isolation separator toward the center, and a sufficient power generation area can be ensured.

  Various shapes can be applied as the chamfered shape of the joint region as long as each corner portion of the square is removed. For example, an R-chamfered shape in which each corner portion of the joint region is chamfered in an arc shape. be able to. In this case, it is desirable to set the radius of curvature of the R chamfered shape so that the bonding area is as large as possible in the vicinity of each corner of the bonding region. For example, at each corner of the joint region, the radius of curvature of the R chamfer of the inner peripheral region may be set to be smaller than the radius of curvature of the R chamfer of the outer peripheral region. By appropriately setting the radii of curvature in this case, the joining region can be arranged as a band-like region having a constant width, thereby preventing the joining reliability from being lowered at a portion where the width is partially narrowed. be able to.

  The joining region can be set to a desired belt-like region within a range surrounded by the outer peripheral shape of the cell body and the inner peripheral shape of the isolation separator. In this case, the outer peripheral end of the cell body is formed in the same planar shape as the outer peripheral shape of the joining region, and the inner peripheral end of the isolation separator is the same as the inner peripheral shape of the joining region. If the planar shape is formed, the range in which the cell body and the isolation separator can be joined can be utilized to the maximum extent.

  The joining between the isolation separator and the cell body in the joining region is not particularly limited, but, for example, a brazing material can be used. For example, in a state where brazing material is applied to partial regions corresponding to the bonding regions of the isolation separator and the cell main body, the cell body is moved through the bonding region by aligning and heating both. It can be integrated with the isolation separator.

  The cell body and the isolation separator can be formed in various structures. The cell main body may include other functional layers in addition to the fuel electrode layer, the air electrode layer, and the solid electrolyte, and a layer serving as a support base among the layers is not particularly limited. As a typical structure of the cell body, the fuel electrode layer can be used as a supporting base, and the air electrode layer can be disposed on the surface of the cell body exposed at the opening of the isolation separator. Moreover, the said isolation | separation separator can be formed with the metal material which has flexibility, for example. The present invention can be applied not only to a solid oxide fuel cell that is a unit cell, but also to a solid oxide fuel cell stack configured by stacking a plurality of unit cells. .

  As described above, according to the present invention, in the unit cell of the solid oxide fuel cell, the joining area for joining the cell main body and the separator separator is a plane in which each corner of the outer peripheral shape and the inner peripheral shape is chamfered. Since it has a shape, it is possible to relieve stress concentrated on the corner and to secure a bonding area. Therefore, it is possible to improve the gas sealing performance of the unit cell by improving the bonding reliability between the cell body and the isolation separator and reliably preventing gas leakage in the bonding area, and further, solid oxide fuel cell It is also effective in improving the utilization rate.

It is a side view of the solid oxide fuel cell of this embodiment. FIG. 2 is a top view of the solid oxide fuel cell of FIG. 1. It is a typical section structure figure of the state where each constituent element was disassembled about one unit cell. It is a top view of an interconnector in a unit cell. It is a top view of a gas seal part in a unit cell. It is a top view of a fuel electrode frame in a unit cell. It is a top view of the isolation separator in a unit cell. It is a top view of a cell body in a unit cell. FIG. 9 is a plan structural view of a state in which the cell main body of FIG. 8 is joined to the isolation separator of FIG. 7. It is a figure explaining the effect in the case of employ | adopting the shape of the junction area | region of FIG. 9 in the unit cell of this embodiment. It is a figure explaining the joining process of an isolation separator and a cell main body among the manufacturing processes of the unit cell of this embodiment. It is a figure which shows the other Example regarding the chamfering shape of a joining area | region.

  Preferred embodiments of the present invention will be described below with reference to the drawings. However, the embodiment described below is an example of a form to which the technical idea of the present invention is applied, and the present invention is not limited by the content of the present embodiment.

  First, a specific structure of a solid oxide fuel cell to which the present invention is applied will be described. FIG. 1 shows a side view of the solid oxide fuel cell 1 of the present embodiment, and FIG. 2 shows a top view of the solid oxide fuel cell 1 of FIG. 1 corresponds to a side view seen from the direction of arrow A in FIG.

  As shown in FIGS. 1 and 2, the solid oxide fuel cell 1 of the present embodiment is a fuel cell stack in which a plurality of fuel cell cells (hereinafter referred to as unit cells) 3, which are basic structural units, are stacked. 2 is provided. The fuel cell stack 2 is integrally fixed by a plurality of bolts B1 to B8 and a plurality of nuts N. Of the bolts B1 to B8, the four bolts B1, B3, B5, and B7 located at the four corners in the rectangular plane of FIG. 2 are used only as connecting members for fixing the fuel cell stack 2. On the other hand, among the bolts B1 to B8, the four bolts B2, B4, B6, and B8 located on the four sides in the rectangular plane of FIG. 2 communicate with the through holes along the stacking direction in addition to the connecting members. These function as a part of a fuel gas flow path (fuel gas flow path) or an oxidant gas flow path (air flow path). Specifically, the bolt B2 communicates with the fuel gas introduction pipe Fin on the inlet side of the fuel gas flow path, and the bolt B6 opposite to the bolt B2 communicates with the fuel gas discharge pipe Fout on the outlet side of the fuel gas flow path. . Further, the bolt B4 communicates with the air introduction pipe Ain on the inlet side of the air flow path, and the bolt B8 at a position opposite to the bolt B4 communicates with the air discharge pipe Aout on the outlet side of the air flow path.

  Next, the basic structure of the unit cell 3 included in the solid oxide fuel cell 1 of FIG. 1 will be described. FIG. 3 shows a schematic cross-sectional structure of each unit cell 3 in a state where each component is disassembled. The unit cell 3 shown in FIG. 3 includes a cell body 10 that performs a power generation function. The cell body 10 is formed by laminating a fuel electrode layer 11, a solid electrolyte layer 12, and an air electrode layer 13 in order from the lower layer side. The unit cell 3 includes a pair of upper and lower interconnectors 20, 21, a fuel electrode side current collector 22 disposed between the lower interconnector 20 and the fuel electrode layer 11, and an upper interconnector 21. The air electrode side current collector 23 disposed between the air electrode layer 13, the fuel electrode frame 24 surrounding the side surface of the fuel electrode layer 11, and the cell body 10 are integrally joined. An isolation separator 25 that separates the fuel gas flow path Fp on the side and the air flow path Ap on the air electrode layer 13 side, and a gas seal portion 26 disposed between the fuel electrode frame 24 and the lower interconnector 20. And a gas seal portion 27 disposed between the isolation separator 25 and the upper interconnector 21.

  The fuel electrode layer 11 is in contact with a fuel gas serving as a hydrogen source and functions as an anode of the unit cell 3. Since the fuel electrode layer 11 serves as a support base layer that supports the cell body 10, it is desirable to form the fuel electrode layer 11 with a sufficient thickness to ensure mechanical strength. For example, as the material of the fuel electrode layer 11, cermet made of metal particles such as Ni and ceramic particles can be used. The solid electrolyte layer 12 is made of various solid electrolytes having ionic conductivity. For example, as the material of the solid electrolyte layer 12, YSZ, ScSZ, SDC, GDC, perovskite oxide, or the like can be used. The air electrode layer 13 is in contact with air gas serving as an oxygen source and functions as a cathode of the unit cell 3. For example, as the material of the air electrode layer 13, perovskite oxides, various noble metals, and cermets of noble metals and ceramics can be used. The fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13 all have a square (eg, square) planar shape.

  Hereinafter, the structure of the main constituent members in the unit cell 3 will be described with reference to FIGS. 4 to 9 are the same as those in FIG. 2 in the plane. First, the lower interconnector 20 is responsible for electrical connection with the unit cell 3 adjacent to the lower layer, and the upper interconnector 21 is responsible for electrical connection with the unit cell 3 adjacent to the upper layer. As shown in FIG. 4, the interconnectors 20 and 21 are thin metal plates made of, for example, ferritic stainless steel, and eight round holes through which the bolts B1 to B8 pass are formed in the outer edge portions. The fuel electrode side current collector 22 joined to the lower interconnector 20 is made of, for example, Ni felt having air permeability, and the air electrode side current collector 23 joined to the upper interconnector 21 is For example, it consists of a metal and a conductive ceramic.

  The lower gas seal portion 26 is made of, for example, an insulating material such as mica, and serves to seal the fuel gas flow path Fp in the unit cell 3. As shown in FIG. 5, an opening 30 is formed at the center of the gas seal portion 26, and eight round holes through which the bolts B <b> 1 to B <b> 8 pass are formed at the outer edge portion. Of these, the opening 30 is formed with four notches that extend to the outer edge on two opposing sides of the square. As will be described later, the notch formed in the opening 30 becomes a part of the fuel gas flow path Fp. Since the upper gas seal portion 27 has a planar structure obtained by rotating the gas seal portion 26 of FIG. 5 by 90 degrees in a plane, the description thereof is omitted. In this case, the cutout formed in the opening 30 of the upper gas seal portion 27 becomes a part of the air flow path Ap.

  The fuel electrode frame 24 is made of a metal material such as ferritic stainless steel, for example, and has a role of fixing the cell body 10 and the isolation separator 25 to the unit cell 3. As shown in FIG. 6, an opening 31 is formed in the center of the fuel electrode frame 24, four openings 32 are formed along each side of the four sides, and the bolts B1, B3, Four round holes corresponding to B5 and B7 are formed. The central opening 31 faces the rectangular portion of the opening 30 (FIG. 5) of the gas seal portion 26, but no notch is formed. The four openings 32 on each side are formed in a groove shape extending from the portion overlapping the respective round holes of the interconnector 20 and the gas seal portion 26 to both sides in the side direction. Therefore, the fuel gas flow path Fp from the bolt B2 on the inlet side to the bolt B6 on the outlet side through the surface of the fuel electrode layer 11 has a round hole on each of the two sides of the interconnector 20 and the gas seal portion 26, and fuel. Each of the openings 32 on the two sides of the pole frame 24 and the cutouts of the opening 30 of the gas seal portion 26 are included.

  Next, the structure of the isolation separator 25 and the cell body 10 will be described as a characteristic structure of the unit cell 3 of the present embodiment. FIG. 7 shows a planar structure of the isolation separator 25. The isolation separator 25 is formed in a frame-like thin plate having a thickness of about 0.02 to 0.3 mm using a metal material such as ferritic stainless steel as a flexible metal material. As shown in FIG. 7, an opening 33 is formed at the center of the separator 25, and four openings 34 are formed along the four sides. The bolts B1, B3, B5 are formed at the four corners. , Four round holes corresponding to B7 are formed. Among these, the four openings 34 and the four round holes are formed in the same position and the same shape as the fuel electrode frame 24. On the other hand, the central opening 33 has a shape (R chamfering shape) in which four corners of the square facing the opening 31 of the fuel electrode frame 24 are chamfered into an arc shape having a radius of curvature R1.

  FIG. 8 shows a planar structure of the cell body 10. As shown in FIG. 8, the cell body 10 has a shape (R chamfered shape) in which four corners of a square outer peripheral shape are chamfered into an arc shape having a curvature radius R2. On the other hand, the outer peripheral shape of the upper air electrode layer 13 of the cell main body 10 is smaller than the outer peripheral shape of the cell main body 10. As described with reference to the cross-sectional structure of FIG. 3, the air electrode layer 13 can be exposed to the opening 33 of the isolation separator 25.

  The air passage Ap extending from the inlet-side bolt B4 to the outlet-side bolt B8 via the surface of the air electrode layer 13 has a round hole on each of the two sides of the interconnector 21 and the gas seal portion 27, and an isolation separator. 25 each of the opening 34 on the two sides and the notch of the opening 30 of the gas seal portion 27 (the notch of the opening 30 of the gas seal portion 26 in FIG. 5 is formed at a position rotated 90 degrees). Consists of.

  Here, FIG. 9 shows a planar structure in a state where the cell body 10 of FIG. 8 is joined to the isolation separator 25 of FIG. As shown in FIG. 9, the back surface on the inner peripheral side of the isolation separator 25 and the surface on the outer peripheral side of the cell body 10 are joined via a joining region 40. The joining region 40 is a belt-like region having a predetermined width surrounded by an outer peripheral shape that matches the outer periphery of the cell body 10 and an inner peripheral shape that matches the inner periphery (opening 33) of the separator 25. Accordingly, each corner of the outer peripheral shape of the joining region 40 is chamfered in an arc shape with the same curvature radius R2 as in FIG. 8, and each corner of the inner peripheral shape of the joining region 40 is a circle with the same curvature radius R1 as in FIG. It is chamfered in an arc. In addition, although the joint between the isolation separator 25 and the cell body 10 in the joining region 40 is not particularly limited, for example, the joining is performed using a brazing material.

  With reference to FIG. 10, the effect in the case of employ | adopting the shape of the junction area | region 40 of FIG. 9 in the unit cell 3 of this embodiment is demonstrated. FIG. 10A is a diagram schematically showing a planar structure corresponding to FIG. 9, and FIG. 10B is an outer peripheral side of the cell body 10 as in the past for comparison with the present embodiment. FIG. 5 is a diagram schematically showing a planar structure as a comparative example when chamfering only the inner peripheral side of the separator 25 without chamfering. Here, in FIGS. 10A and 10B, it is assumed that both the joint regions 40 have the same size in the basic outer peripheral shape and the inner peripheral shape excluding the chamfered portion. Therefore, it can be seen that the width W1 at the four sides of the bonding region 40 is common in FIGS. 10A and 10B.

  On the other hand, each corner of the joining region 40 in FIG. 10A has a width W2 sandwiched between the outer arc and the inner arc, and each corner of the joining region 40 in FIG. The width W3 is sandwiched between the arc and the inner right-angle shape, and satisfies the relationship W2> W3. Therefore, the bonding area 40 of FIG. 10A according to the present embodiment has a larger area than the bonding area 40 of FIG. 10B having a conventional structure because the inner peripheral side is chamfered near the corner. . Further, in FIG. 10B of the conventional structure, there is a right-angled shape portion where stress is likely to concentrate in the vicinity of the corner portion of the joining region 40, whereas in FIG. Since there is no right-angled or acute-angled shape portion near the corner of the region 40, stress is less likely to concentrate. Thus, by adopting the shape of the joining region 40 of this embodiment, compared with the conventional structure, the joining area in the vicinity of the corner can be increased, and the stress concentration caused by the right-angled or acute-angled shaped portion can be concentrated. Since this can be avoided, it is possible to secure the bonding reliability in the bonding region 40 and improve the gas sealing performance of the separator 25.

  In the structure of the present embodiment, the relationship between the width W1 of each side and the width W2 of the corner in FIG. 10A is not particularly limited. For example, by setting a relationship of W1 = W2, The region 40 may be formed in a band-like region having a constant width. In this case, in the joining region 40, an R-chamfered curvature radius R1 on the inner peripheral side (opening 33 of the separator 25) and an R-chamfered curvature radius R2 on the outer peripheral side (the outer periphery of the cell body 10) are set as R1. It is desirable to set the relationship <R2. If the respective curvature radii R1 and R2 are excessively increased, it is not preferable because the area of the cell body 10 in the unit cell 3 is restricted, and conversely if the respective curvature radii are excessively decreased, the stress concentration in the joint region 40 is reduced. The effect of mitigating cannot be obtained. As a specific dimension example, for example, when one side of the cell body 10 is about 120 mm, R1 = 5 μm and R2 = 5.5 μm can be set.

  10A, the outer peripheral shape of the joining region 40 matches the outer peripheral shape of the cell body 10, and the inner peripheral shape of the joining region 40 is identical to the inner peripheral shape of the isolation separator 25. However, the shape of the joining region 40 can be determined without being limited to this. That is, the bonding region 40 may have a shape in which the outer peripheral shape is inside the outer peripheral shape of the cell body 10 and the inner peripheral shape is outside the inner peripheral shape of the isolation separator 25. That is, the bonding region is in a region surrounded by the outer peripheral shape of the cell body 10 and the inner peripheral shape of the separator 25, and various shapes are formed by chamfering each corner on the outer peripheral side and the inner peripheral side. You can have it. As long as the corners of one or both of the outer peripheral shape of the cell body 10 and the inner peripheral shape of the separator 25 are not chamfered, the outer peripheral shape and the inner peripheral corner of the bonding region 40 itself are not chamfered. The present invention can be applied if it is chamfered.

  Next, of the manufacturing process of the unit cell 3 of the present embodiment, a process of joining the isolation separator 25 and the cell body 10 will be mainly described. First, an isolation separator 25 having a planar structure shown in FIG. 7 is manufactured by punching a metal plate by a known method. At this point, the central opening 33 of the separator 25 is in a state where each square corner is chamfered with a radius of curvature R1.

  On the other hand, a fuel electrode green sheet to be a support base layer is formed by a well-known method, a solid electrolyte green sheet is formed, and a laminate of the solid electrolyte green sheet is formed on the upper layer of the fuel electrode green sheet. Next, the obtained laminate is processed into a predetermined rectangular shape and then fired to obtain a sintered body composed of the fuel electrode layer 11 and the solid electrolyte layer 12. At this point, the outer peripheral portion of the cell body is in a state where each square corner is chamfered with a radius of curvature R2. Subsequently, the cell body 10 having the planar structure of FIG. 8 is produced by forming the air electrode layer 13 in a predetermined position on the upper layer of the obtained sintered body.

  Next, as shown in FIG. 11A, a brazing material is applied to the inner peripheral region corresponding to the bonding region 40 on the lower surface of the isolation separator 25, and the bonding region 40 is formed on the upper surface of the solid electrolyte layer 12 of the cell body 10. A brazing material is applied to the outer peripheral area corresponding to the above. As the brazing material, for example, an Ag-based brazing material containing Ag as a main component and some Pd is used. In this state, as shown in FIG. 11B, the separator separator 25 and the cell main body 10 are aligned so that the joint regions 40 overlap each other, and the brazing material is heated so that the cell main body 10 is separated from the separator separator 25. Integrated into The unit cell 3 can be obtained by incorporating the isolation separator 25 and the cell body 10 obtained as described above.

  In order to confirm the effect of the unit cell 3 of the present embodiment, a gas leak test was performed. Specifically, in the unit cell 3 of FIG. 3, an aqueous solution colored with a red dye is applied from the fuel gas flow path Fp side to the joining region 40, and the aqueous solution is applied to the opposite air flow path Ap side. Pass / fail was judged by visually confirming a red colored portion. Then, for the case where the planar structure of the bonding region 40 of the present embodiment is applied and the case where the planar structure of the bonding region 40 of the present embodiment is not applied, 300 unit cells 3 are prepared and the above test is performed. It was. As a result, in the case of the unit cell 3 to which the planar structure of the junction region 40 of the present embodiment is applied, a pass rate of 87% is obtained, whereas the unit cell 3 to which the planar structure of the junction region 40 of the present embodiment is not applied. In this case, the acceptance rate was 45%, and the effect of improving the gas sealing property in the unit cell 3 of the present embodiment could be confirmed.

  The contents of the present invention have been specifically described above based on the present embodiment, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, in the present embodiment, the case where each corner portion of the bonding region 40 has an R chamfered shape has been described, but the chamfered shape of the bonding region 40 is not limited to the R chamfering.

  FIG. 12 shows another embodiment relating to the chamfered shape of the joining region 40. FIG. 12A shows an example in which the joining region 40 has a shape (C chamfered shape) in which four corners are chamfered linearly. 12A, unlike the case of FIG. 10A, the inner peripheral side and the outer peripheral side of each corner of the joint region 40 are chamfered by a straight line that intersects each two sides at 45 degrees. ing. In this case, since the internal angle formed by the straight portion of the C-chamfered shape with each side is an obtuse angle (135 degrees) and there is no right-angled or acute-shaped portion, concentration of stress can be avoided. The width W1 on the four sides of the joining region 40 and the width W4 between the outer periphery and the inner periphery of each corner are not particularly limited, but can be set to W1 = W4 or W1 <W4.

  On the other hand, FIG. 12 (B) shows an embodiment having a shape (chamfered shape consisting of three straight lines) in which both ends of the C chamfered portion in the joining region 40 of FIG. 12 (A) are further chamfered linearly. . 12B, the angle formed by each side and each straight line portion among the respective corners of the bonding region 40 is a larger obtuse angle than that in FIG. Increases the effect of avoiding concentration. The width W1 on the four sides of the bonding region 40 and the width W5 between the outer periphery and the inner periphery of each corner are not particularly limited, but can be set to W1 = W5 or W1 <W5. As described above, various chamfered shapes including straight lines and curves can be adopted as long as a right-angle or acute-angle portion is removed at the corner of the bonding region 40.

  Further, the contents of the present invention are not limited by the above-described embodiment with respect to other points, and the contents disclosed in the above-described embodiment are not limited to the contents disclosed in the above-described embodiments as long as the effects of the present invention can be obtained. Is possible. For example, the structure, shape, material, formation method and the like of each constituent member in the unit cell 3 can be appropriately changed as long as the effects of the present invention can be obtained.

DESCRIPTION OF SYMBOLS 1 ... Solid oxide fuel cell 2 ... Fuel cell stack 3 ... Unit cell (fuel cell)
DESCRIPTION OF SYMBOLS 10 ... Cell main body 11 ... Fuel electrode layer 12 ... Solid electrolyte layer 13 ... Air electrode layer 20, 21 ... Interconnector 22 ... Fuel electrode side collector 23 ... Air electrode side collector 24 ... Fuel electrode frame 25 ... Isolation separator 26, 27 ... Gas seal parts B1-B8 ... Bolt N ... Nut Ain ... Air introduction pipe Aout ... Air discharge pipe Ap ... Air flow path Fin ... Fuel gas introduction pipe Fout ... Fuel gas discharge pipe Fp ... Fuel gas flow path

Claims (9)

At least a fuel electrode layer in contact with the fuel gas, an air electrode layer in contact with the oxidant gas, and a solid electrolyte layer in which the fuel electrode is disposed on one surface side and the air electrode is disposed on the other surface side are laminated. A plate-shaped cell main body,
The cell body is provided with an opening that is disposed on one surface side and penetrates in the thickness direction, and at least a part of the fuel electrode layer or the air electrode layer of the cell body is exposed from the opening, and A frame-shaped isolation separator having a joint for joining with the solid electrolyte layer of the cell body;
A solid oxide fuel cell comprising:
The joining portion has a planar shape having an outer periphery and an inner periphery, and both the outer periphery shape and the inner periphery shape are planar shapes chamfered at four corners of a square. The outer peripheral end of the cell body is formed in the same planar shape as the outer peripheral shape of the joint,
An end portion on the inner peripheral side of the isolation separator is formed in the same planar shape as the inner peripheral shape of the joint portion.
The solid oxide fuel cell according to claim 1.   3. The solid oxide fuel cell according to claim 1, wherein the chamfered planar shape of each of the outer peripheral shape and the inner peripheral shape of the joint portion is an R chamfered shape.   4. The solid oxide fuel cell according to claim 3, wherein the R chamfered shape of the outer peripheral shape is formed with a larger radius of curvature than the R chamfered shape of the inner peripheral shape.   3. The solid oxide fuel cell according to claim 1, wherein the chamfered planar shape of each of the outer peripheral shape and the inner peripheral shape of the joint is a C chamfered shape.   The solid oxide fuel cell according to any one of claims 3 to 5, wherein the joint portion is a band-shaped region having a constant width.   The solid oxide fuel cell according to any one of claims 1 to 6, wherein the joining portion is made of a brazing material, and the cell main body and the isolation separator are joined by brazing. .   The support body of the cell body is the fuel electrode layer, and the air electrode layer is disposed on a surface of the cell body exposed from the opening of the isolation separator. 8. The solid oxide fuel cell according to any one of 7 above. The solid oxide fuel cell according to any one of claims 1 to 8, wherein the isolation separator is made of a flexible metal material.

Images