JP5705636B2 - Solid oxide fuel cell - Google Patents

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 is easily damaged at the joint 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 at the corners of the four corners as compared to the 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. As a structure for alleviating stress concentration at the corners of the four corners of the joining region, it is effective to make the shape of the opening of the isolation separator a chamfered corner of each square. However, when the cell body is joined to the separator having such a structure, for example, when the rectangular air electrode layer on the upper layer side of the cell body is exposed to the opening, the corners of the separator separator are chamfered. The interval between the portion and the corner of the air electrode layer becomes narrow. As a result, there is a possibility that an electrical short circuit may occur due to the air electrode layer coming into contact with the isolation separator or the joint, or migration of brazing material or the like at the joint. On the other hand, if the size of the air electrode layer is reduced toward the center, a sufficient distance can be secured between the chamfered portion of the corner of the separator and the corner of the air electrode layer, but in this case, the power generation area of the unit cell is small. It cannot be avoided. Thus, when adopting a structure in which the four corners on the inner peripheral side of the separator separator are chamfered, it is difficult to achieve both good electrical reliability of the unit cell and securing a sufficient power generation area.

  The present invention has been made to solve these problems, and while maintaining a sufficient distance between the cell body and the isolation separator, it ensures good electrical reliability while preventing a reduction in the power generation area of the unit cell. An object of the present invention is to provide a solid oxide fuel cell.

In order to solve the above problems, a solid oxide fuel cell of 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 layer on one surface side. obtain Bei and placed cell body and the other surface a solid electrolyte the air electrode layer is disposed on the side layers are stacked, is disposed on one surface side of the cell body, an opening through the thickness direction And a separator having a frame-like shape having a joint for joining with the cell body, and the opening of the separator has a first planar shape chamfered at four corners of a square, The predetermined layer of the cell body has a second planar shape chamfered at four corners of a square, and the first planar shape is in a positional relationship surrounding the second planar shape with a predetermined interval. The first planar shape and the Each of the two planar shapes chamfered is an R-chamfered shape, and the radius of curvature of the R-chamfered shape of the second planar shape is the radius of curvature of the R-chamfered shape of the first planar shape. The predetermined layer is the air electrode layer or the fuel electrode layer, and the air electrode layer or the fuel electrode layer, which is the predetermined layer in a plan view, is exposed from the opening. Yes.
In order to solve the above problems, the solid oxide fuel cell of 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 on one surface side. A cell body in which a layer is disposed and a solid electrolyte layer in which the air electrode layer is disposed on the other surface side, and an opening that is disposed on one surface side of the cell body and penetrates in the thickness direction. And a solid oxide fuel cell having a frame-shaped isolation separator having a joint for joining to the cell body, wherein the openings of the separator are chamfered at four corners of a square. The predetermined layer of the cell body has a second planar shape chamfered at four corners of the square, and the first planar shape is separated from the second plane by a predetermined interval. It is in a positional relationship surrounding the planar shape, The chamfered planar shape of each of the first planar shape and the second planar shape is a C chamfered shape, and is a region sandwiched between the first planar shape and the second planar shape. W1 <W4, where W1 is the width of the portion where the C chamfered shapes do not face each other and W4 is the width of the portion where the C chamfered shapes are opposed, and the predetermined layer is the air electrode layer Alternatively, the air electrode layer or the fuel electrode layer, which is the fuel electrode layer and is the predetermined layer in a plan view, is exposed from the opening.

  According to the solid oxide fuel cell of the present invention, 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, and the surface of the predetermined layer of the cell body is formed in the opening. In the structure to be exposed, the first planar shape of the opening surrounds the second planar shape of the predetermined layer with a predetermined interval, and the first and second planar shapes are chamfered at the four corners of the square, respectively. . Therefore, the distance between the separator and the predetermined layer can be increased according to the chamfering amount of the corner portion of the second planar shape, as compared with the structure in which the outer periphery of the predetermined layer is not chamfered. For this reason, when the isolation separator and the predetermined layer are disposed close to each other, an electrical short circuit due to contact, migration of the joint portion, or the like can be prevented. In addition, in the structure in which the outer periphery of the predetermined layer is not chamfered, the power generation area is reduced when the size of the predetermined layer is reduced toward the center in order to secure the distance between the separator and the predetermined layer. According to the structure of the invention, a sufficient power generation area can be ensured.

  The cell body can be formed in various structures. For example, a predetermined layer exposed in the opening may be used as the air electrode layer. Further, for example, the layer serving as the support base of the cell body may be the fuel electrode layer. That is, the fuel electrode layer, the solid electrolyte layer, and the air electrode layer are stacked in order from the lower layer side, and the plane size is reduced in this order, whereby the surface of the air electrode layer is exposed from the opening. Can be realized. The cell body may include other functional layers in addition to the fuel electrode layer, the air electrode layer, and the solid electrolyte layer, and the layer serving as a support base among the layers is not particularly limited.

  As the first and second planar shapes, various shapes can be applied as long as each square corner is removed. For example, each corner of the first and second planar shapes is a circle. An arc chamfered round chamfered shape can be used. In this case, the outer peripheral shape of the “predetermined layer” located on the inner side of the inner circumferential shape of the “separation separator” located on the outer side: the radius R1 of the R chamfering of the first flat shape: the R of the second planar shape. It is desirable to set the radius of curvature R2 of the chamfer so as not to be small (that is, R1 ≦ R2 + W). By appropriately setting the radii of curvature in this case, the region between the first and second planar shapes can be a band-shaped region having a constant width, and a portion where the width is partially narrowed (particularly It is possible to prevent a decrease in electrical reliability (difficult to cause electrical short-circuiting) at locations where electrical short-circuiting such as the four corners is likely to occur. In addition, when R1 = R2 + W is set, the first planar shape and the second planar shape can be provided as a constant belt-like width including the four corners, and in addition to a structure in which electrical short-circuiting is difficult at the four corners, a predetermined layer It is also possible to provide a wider area (for example, an air electrode layer). For example, it is good also as C chamfering shape which chamfered each corner | angular part of said 1st and 2nd planar shape linearly.

  In addition to the first and second planar shapes, the third planar shape of the outer peripheral end of the cell body may be chamfered at four corners of a square. As a result, stress that tends to concentrate on acute or right-angled corners at the joints surrounded by the second and third planar shapes can be alleviated, and sufficient adhesion between the cell body and the isolation separator can be achieved. Therefore, the gas sealing performance of the unit cell can be improved.

  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. 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 structure in which the cell body of the unit cell and the separator are joined, the opening of the separator and the predetermined layer of the cell body exposed in the opening are each square. The chamfered planar shape at the four corners effectively prevents an electrical short-circuit that becomes a problem when the separator and the predetermined layer are arranged at a short distance, improves the electrical reliability, and reduces the predetermined layer. A sufficient power generation area of the unit cell can be ensured without reducing the size.

1 is a side view of a solid oxide fuel cell according to a first 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. It is a figure explaining the effect at the time of employ | adopting the structure of the isolation separator of FIG. 7, and the structure of the cell main body of FIG. 8 in the unit cell of 1st Embodiment. It is a figure explaining the joining process of an isolation separator and a cell main body mainly among the manufacturing processes of the unit cell of 1st Embodiment. It is a plane structure figure of the cell main part in the unit cell of a 2nd embodiment. FIG. 13 is a plan structural view of a state in which the cell main body of FIG. 12 is joined to the isolation separator of FIG. It is a figure explaining the effect at the time of employ | adopting the structure of the isolation separator of FIG. 7, and the structure of the cell main body of FIG. 12 in the unit cell of 2nd Embodiment. In the unit cell of 3rd Embodiment, it is the 1st example which deform | transformed the chamfering shape of the isolation separator and cell main body of 1st Embodiment or 2nd Embodiment. In the unit cell of 3rd Embodiment, it is the 2nd example which deform | transformed the chamfering shape of the isolation separator and cell main body of 1st Embodiment or 2nd Embodiment.

  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 Embodiment]
Hereinafter, a first embodiment of a solid oxide fuel cell to which the present invention is applied will be described in detail. FIG. 1 shows a side view of the solid oxide fuel cell 1 of the first 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 first embodiment is a fuel cell in which a plurality of fuel cell cells (hereinafter referred to as unit cells) 3 that are basic structural units are stacked. A stack 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 first 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 chamfered shape) in which the corners of the 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 square outer peripheral shape. On the other hand, the outer peripheral shape of the upper air electrode layer 13 of the cell body 10 is smaller than the outer peripheral shape of the cell body 10, and the corners of the four corners of the square are chamfered into an arc shape with a radius of curvature R2 (R Chamfered shape). The reason why the size of the air electrode layer 13 is reduced is that the air electrode layer 13 can be exposed to the opening 33 of the isolation separator 25 as described with reference to the cross-sectional structure of FIG.

  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. Further, the air electrode layer 13 is disposed in a state where the air electrode layer 13 is exposed to the opening 33. The outer peripheral shape of the joining region 40 is the same square as the outer peripheral shape of the cell body 10 in FIG. 8, and each corner of the inner peripheral shape of the joining region 40 is chamfered in an arc shape with the same curvature radius R1 as in FIG. Yes. 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 based on the structure of the isolation | separation separator 25 of FIG. 7 and the structure of the cell main body 10 of FIG. 8 is demonstrated in the unit cell 3 of 1st Embodiment. FIG. 10 (A) is a diagram schematically showing the vicinity of the center of the same planar structure as FIG. 9, and FIG. 10 (B) is a comparison with FIG. 10 (A) for comparison with the first embodiment. FIG. 6 is a diagram schematically showing a planar structure as a comparative example in the case of using an isolating separator 25 having the same shape as in FIG. 5 and an air electrode layer 13a having no chamfered portion on the outer peripheral side. Here, in FIG. 10A and FIG. 10B, a gap region G sandwiched between the inner peripheral side (opening 33) of the separator 25 and the outer peripheral side of the air electrode layers 13 and 13a is shown. Yes. Note that the bonding region 40 of FIG. 9 is not shown. The gap region G is a region where the upper surface of the solid electrolyte layer 12 is exposed in a band shape. 10A and 10B, it is assumed that each gap region G has a common size in both the 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 gap region G is the same in FIGS. 10A and 10B.

  On the other hand, each corner (four corners) of the gap region G in FIG. 10A has a width W2 sandwiched between the outer arc and the inner arc, and each corner of the gap region G in FIG. It can be seen that the width W3 is sandwiched between the outer arc and the inner right-angled shape, and satisfies the relationship W2> W3. In addition, the air electrode whose outer peripheral shape is reduced toward the center so that a corner portion can be arranged at a position having the same width W2 as that in FIG. 10A inside the air electrode layer 13a in FIG. The layer 13b is shown by being overlaid with a broken line.

  When the gap region G in FIG. 10A of the first embodiment is compared with the gap region G in the case of arranging the air electrode layer 13a in FIG. 10B of the comparative example, in FIG. Since the width W3 is reduced by the amount that the inner peripheral side is not chamfered in the vicinity, for example, an electrical short caused by contact between the air electrode layer 13 and the separator 25 or the joining region 40, migration of the brazing material in the joining region 40, or the like. This causes a decrease in electrical reliability. Further, when the gap region G of FIG. 10A of the first embodiment is compared with the gap region G in the case where the small-sized air electrode layer 13b as shown in FIG. Although the width W2 near the portion is the same, the size of the air electrode layer 13b in FIG. 10B is reduced and the power generation area is reduced, so that the power generation performance of the unit cell 3 is reduced. Thus, by adopting the structure of the first embodiment, it is possible to achieve both improvement in electrical reliability and securing of a power generation area.

  In the structure of the first 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 the relationship W1 = W2, 40 may be formed in a band-like region having a constant width. In this case, in the gap region G, an R-chamfered curvature radius R1 on the outer peripheral side (opening 33 of the separator 25) and an R-chamfered curvature radius R2 on the inner peripheral side (the outer periphery of the air electrode layer 13) It is desirable to set the relationship of R1 ≦ R2 + W. If the respective radii of curvature R1 and R2 are too large, it is not preferable because the area of the air electrode layer 13 is limited. Conversely, if the respective radii of curvature are too small, the stress concentration in the joining region 40 (FIG. 9) is alleviated. Effect is insufficient. For example, when one side of the opening 33 of the separator 25 is 110 mm and one side of the air electrode layer 13 is 107 mm, W1 = W2 = 1.5 mm, R1 = 5 mm, R2 = It can be set to about 3.5 mm. In this case, R1 = R2 + W, and it is preferable to employ this because it is possible to prevent both electrical shorts and ensure the air electrode area. Under this condition, one side of the air electrode layer 13b in FIG. 10 (B) is 105 mm, and the area of the air electrode layer 13 in FIG. 10 (A) is the area of the air electrode layer 13b in FIG. 10 (B). Compared to, it can be increased by about 4%, and the power generation area will be expanded accordingly.

  Next, steps related to a characteristic structure among the manufacturing steps of the unit cell 3 of the first embodiment will be 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 time, an opening 33 in which each corner of the square is chamfered with a curvature radius R1 is formed in the center of the isolation separator 25 by, for example, punching.

  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. 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. At this time, the air electrode layer 13 is formed by a laminated pattern in which each square corner is chamfered with a curvature radius R2.

  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 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.

[Second Embodiment]
Hereinafter, a second embodiment of the solid oxide fuel cell to which the present invention is applied will be described in detail. Since the second embodiment is common to the first embodiment in many respects, differences from the first embodiment will be mainly described below. Since FIGS. 1 to 7 and FIG. 11 shown in the first embodiment are common to the second embodiment, description thereof is omitted.

  FIG. 12 is a diagram illustrating a planar structure of the cell body 10 of the second embodiment, and corresponds to FIG. 8 of the first embodiment. Unlike FIG. 8, the cell body 10 shown in FIG. 12 has a shape (R chamfered shape) in which four corners of a square outer peripheral shape are chamfered into an arc shape having a radius of curvature R3. In addition, the basic shape of the outer periphery and the inner periphery excluding the chamfered portion of the cell body 10 in FIG. 12 is assumed to be the same size as FIG. FIG. 13 shows a planar structure in a state where the cell body 10 of FIG. 12 is joined to the isolation separator 25 (FIG. 7) of the second embodiment. As shown in FIG. 13, the isolation separator 25 of the second embodiment has the same shape as that of the first embodiment, but the shape of the joining region 40 is different from that of the first embodiment (FIG. 9). That is, in the joining region 40 of the second embodiment, in addition to the inner peripheral shape, each corner of the outer peripheral shape is chamfered with the above-described curvature radius R3 reflecting the structure of the cell body 10 of FIG.

  FIG. 14 is a diagram schematically showing the vicinity of the center of the planar structure including the isolation separator 25 of FIG. 7 and the cell body 10 of FIG. 12 in the second embodiment. Correspond. The widths W1 and W2 in the gap region G in FIG. 14 are the same as those in FIG. On the other hand, in the joint region 40 of FIG. 14, the width W11 at the four sides and the width W12 at the corners are shown together. The relationship between the width W11 and the width W12 is not particularly limited. For example, the bonding region 40 may be formed in a band-shaped region having a constant width by setting the relationship W11 = W12. In this case, in the joining region 40, it is desirable to set the R-chamfered curvature radius R3 and the R-chamfered curvature radius R1 of the inner peripheral side at the four corners on the outer peripheral side in a relationship of R3 <R1.

  In the second embodiment, by forming the joining region 40 in the shape shown in FIG. 14, all the right-angled portions in the joining region 40 do not exist, so that the effect that stress is less likely to concentrate can be further enhanced. . Thereby, the joining reliability in the joining area | region 40 is improved, and the further improvement of the gas-seal property of the isolation | separation separator 25 is attained. In the second embodiment, it is natural that the effects related to the electrical reliability and the power generation area derived from the shape of the gap region G are the same as those in the first embodiment.

[Third Embodiment]
The third embodiment of the solid oxide fuel cell to which the present invention is applied will be specifically described below. In the third embodiment, the chamfered shapes of the isolation separator 25 and the cell body 10 are modified. FIG. 15A shows an example in which the R chamfered shape at each corner of the gap region G in FIG. 10A of the first embodiment is replaced with a linearly chamfered shape (C chamfered shape). . The gap region G in FIG. 15A differs from FIG. 10A in that the outer peripheral side (opening 33) and the inner peripheral side (air electrode layer 13) of each corner of the gap region G It is chamfered with a straight line that intersects the two sides at 45 degrees. The width W1 on the four sides of the gap region G 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.

  FIG. 15B shows an example in which both ends of the C chamfered portion in the gap region G of FIG. 15A are further chamfered in a straight line (a chamfered shape consisting of three straight lines). The width W1 on the four sides of the gap region G 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.

  On the other hand, FIG. 16A shows an example in which the R chamfered shape at each corner of the gap region G and the junction region 40 in FIG. 14 of the second embodiment is replaced with a linearly chamfered shape (C chamfered shape). Show. The shape of the gap region G in FIG. 16A is the same as that in FIG. Further, unlike FIG. 14, the joining region 40 in FIG. 16A is chamfered at the inner peripheral side and outer peripheral side of each corner by a straight line that intersects each two sides at 45 degrees. The width W11 on the four sides of the joint region 40 and the width W13 between the outer periphery and inner periphery of each corner are not particularly limited, but can be set to W11 = W13 or W11 <W13.

  16B shows an example in which both ends of the chamfered portion in the gap region G and the joint region 40 in FIG. 16A are further chamfered in a straight line (a chamfered shape consisting of three straight lines). Show. The shape of the gap region G in FIG. 16B is the same as that in FIG. Further, in the joining region 40 in FIG. 16B, the angle formed by each side and each straight line portion among the corner portions becomes a larger obtuse angle than that in FIG. Increases effectiveness. The width W11 on the four sides of the joining region 40 and the width W14 between the outer periphery and the inner periphery of each corner are not particularly limited, but can be set to W11 = W14 or W11 <W14.

  In 3rd Embodiment, it is not restricted to the structure shown in FIG.15 and FIG.16, The various chamfering shape containing a straight line and a curve can be employ | adopted. In this case, the chamfered portion can be shaped freely within a range in which the width of each corner in the gap region G (and the width of each corner in the bonding region 40) can be set appropriately. In the third embodiment, it is natural that the effects relating to the electrical reliability and the power generation area derived from the shape of the gap region G are the same as those in the first and second embodiments.

  As mentioned above, although the content of this invention was concretely demonstrated based on 1st and 2nd embodiment, this invention is not limited to each above-mentioned embodiment, A various change is possible in the range which does not deviate from the summary. Can be applied. For example, each layer constituting the cell body 10 is not limited to the fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13, and may include functional layers having various roles. In this case, the layer serving as the support base in the cell body 10 is not limited to the fuel electrode layer 11 and may be another layer. In addition, the layer bonded to the isolation separator 25 via the bonding region 40 in the cell body 10 is not limited to the solid electrolyte layer 12 and may be another layer. Regarding the other points, the contents of the present invention are not limited by the above embodiments, and can be appropriately changed as long as the effects of the present invention can be obtained. 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 portions 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 G ... Gap area

Claims (7)

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 layer is disposed on one side and the air electrode layer is disposed on the other side. A cell body laminated with;
Is disposed on one surface side of the cell body, with obtain Bei an opening through the thickness direction, a frame-like isolation separator having a bonding portion to be bonded to the cell body,
A solid oxide fuel cell comprising:
The opening of the isolation separator has a first planar shape chamfered at four corners of a square;
The predetermined layer of the cell body has a second planar shape chamfered at four corners of a square,
Ri positional relationship near said first planar shape surrounding said second planar shape with a predetermined interval,
The chamfered planar shapes of the first planar shape and the second planar shape are R chamfered shapes,
The radius of curvature of the R chamfered shape of the second planar shape is larger than the radius of curvature of the R chamfered shape of the first planar shape,
The predetermined layer is the air electrode layer or the fuel electrode layer;
The solid oxide fuel cell, wherein the air electrode layer or the fuel electrode layer, which is the predetermined layer in a plan view, is exposed from the opening . 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 layer is disposed on one side and the air electrode layer is disposed on the other side. A cell body laminated with;
A frame-shaped isolation separator that is disposed on one surface side of the cell body and includes an opening that penetrates in the thickness direction and has a joint that joins the cell body;
A solid oxide fuel cell comprising:
The opening of the isolation separator has a first planar shape chamfered at four corners of a square;
The predetermined layer of the cell body has a second planar shape chamfered at four corners of a square,
The first planar shape is in a positional relationship surrounding the second planar shape via a predetermined interval;
The chamfered planar shapes of the first planar shape and the second planar shape are C chamfered shapes,
Of the region sandwiched between the first planar shape and the second planar shape, the width of the portion where the respective C chamfered shapes do not face each other is W1, and the width of the portion where the respective C chamfered shapes face each other Is W4, W1 <W4,
The predetermined layer is the air electrode layer or the fuel electrode layer;
The solid oxide fuel cell, wherein the air electrode layer or the fuel electrode layer, which is the predetermined layer in a plan view, is exposed from the opening . Solid oxide fuel cell according to claim 1 or 2, wherein the predetermined layer, wherein said an air electrode layer. 4. The solid oxide fuel cell according to claim 3 , wherein the layer serving as a support base of the cell body is the fuel electrode layer. The end on the outer side of the cell body, the solid oxide fuel cell according to any one of claims 1 to 4, characterized in that it has a third planar shape which is chamfered at the rectangular corners. The joint is made by the brazing material, the solid oxide fuel cell according to any one of claims 1 to 5 and the cell body and the isolating separator is characterized in that it is joined by brazing . The isolation separator, solid oxide fuel cell according to any one of claims 1 to 6, characterized in that it is formed by a metal material having flexibility.

Images