JP2014049322A - Fuel battery cell with separator, and fuel battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery cell with a separator in which a jointing part is elongated, and a fuel battery.SOLUTION: A fuel battery cell with a separator comprises: a fuel battery cell body constituted to sandwich a solid electrolyte layer between an air electrode and a fuel electrode; and a plate-like metallic separator that has openings opened on a principal plane and a rear plane and whose rear plane is mounted to the fuel battery cell body via a jointing part constituted of a jointing material containing Ag. The fuel battery cell comprises: a sealing part arranged across an entire circumference of the opening nearer the opening than the jointing part and between a rear plane of the metallic separator and the cell body, and containing a sealing material containing glass; and a restraining part arranged on the metallic separator principal plane at a position opposite to the sealing part across the metallic separator, and constituted of a material having a larger thermal expansion coefficient than that of the sealing material.

Description

  The present invention relates to a fuel cell with a separator and a fuel cell.

  A solid oxide fuel cell using a solid oxide as an electrolyte (hereinafter also referred to as “SOFC” or simply “fuel cell”) is known. The SOFC has, for example, a stack (fuel cell stack) in which a large number of fuel cells each having a fuel electrode and an air electrode are stacked on each surface of a plate-like solid electrolyte layer. Electric power is generated by supplying a fuel gas (for example, hydrogen) and an oxidant gas (for example, oxygen in the air) to the fuel electrode and the air electrode, respectively, and causing a chemical reaction through the solid electrolyte layer.

  The fuel cell is used by being joined to a separator that divides a section where fuel gas and oxidant gas are present. For this joining, usually, a joining portion made of a brazing material such as Ag brazing is used to isolate the fuel gas and the oxidant gas.

  Here, it is known that during operation of the SOFC, hydrogen on the fuel electrode side and oxygen on the air electrode side diffuse and react in the joint, and generate voids in the joint. In order to prevent the formation of voids at the joint, a technique using various Ag alloys having a slow gas diffusion rate as the joint is disclosed (see Patent Documents 1 and 2). By using a material with a slow gas diffusion rate, the life of the brazing material can be extended.

JP 2010-207863 A Special table 2011-522353 gazette

However, with the techniques of Patent Documents 1 and 2, although it is possible to extend the life of the joint (fuel cell), it is not easy to ensure a practically sufficient life of, for example, tens of thousands of hours.
It is an object of the present invention to provide a separator-equipped fuel cell and a fuel cell in which the joint is further extended in life.

  A separator-equipped fuel cell according to the present invention has a fuel cell main body configured by sandwiching a solid electrolyte layer between an air electrode and a fuel electrode, an opening opening in a main surface and a back surface, and a joint containing Ag A separator-equipped fuel cell comprising: a plate-like metal separator attached to the fuel cell body through a joint portion made of a material, wherein the fuel cell with a separator is more than the joint portion. On the opening side and between the back surface of the metal separator and the cell body, the entire periphery of the opening is arranged, and includes a sealing part including a sealing material including glass, and the metal separator, And a constraining portion that is disposed on the metal separator main surface at a position facing the sealing portion and is made of a material having a thermal expansion coefficient larger than that of the sealing material.

A fuel cell with a separator includes a sealing part on the back side of a metallic separator and a restraining part on the main side of the metallic separator that is made of a material having a thermal expansion coefficient larger than that of the sealing material.
The thermal expansion coefficient of the restraining portion on the metal separator main surface side is larger than the thermal expansion coefficient of the sealing portion on the metal separator back surface side. For this reason, when the fuel cell is used, the metal separator tends to bend toward the sealing portion, and as a result, a force acts in the direction of pressing the sealing portion (pressure contact). This force suppresses peeling at the interface between the sealing portion and the metallic separator, and the hermetic sealing performance is improved. As a result, the fuel gas or the oxidant gas is suppressed from reaching the joint.

It is preferable that the constraining portion is disposed over the entire circumference of the opening.
The sealing part is arrange | positioned over the perimeter of an opening part. For this reason, a deformation | transformation of a metal separator can be suppressed over the perimeter of an opening part by arrange | positioning a restraint part over the perimeter of an opening part.

It is preferable that the sealing portion and the restraining portion are integrally formed by a connecting portion disposed on the side surface of the opening of the metal separator.
Since the sealing portion and the restraining portion are integrated, it is possible to further suppress deformation of the metal separator.
Further, the integration of the sealing portion and the restraining portion contributes to a substantial increase in the width of the sealing portion, and the reliability of sealing by the sealing portion is improved.

The thermal expansion coefficient of the material constituting the restraint portion may be smaller than the thermal expansion coefficient of the metallic separator.
The metallic separator and the restraining part are each made of metal and glass, and the thermal expansion coefficient of the restraining part is usually smaller than that of the metallic separator. Even under such conditions, it is possible to suppress the deformation (deflection) of the metal separator by the restraining portion.

A gap may be provided between the joint portion and the sealing portion.
Even if the joint portion and the sealing portion are not in contact with each other, it is possible to suppress deformation (deflection) of the metal separator. In addition, even if gas is contained in the gap, the amount is small, and the influence on the reliability of the joint is small.

It is preferable that the thermal expansion coefficient of the sealing material is 8 ppm / K or more and 12 ppm / K or less in a temperature range from room temperature to 300 ° C.
With this range of thermal expansion coefficient, it is possible to suppress deformation of the metallic separator when the fuel cell is used.

A fuel cell stack according to the present invention includes the fuel cell with a separator described above.
By using the fuel cell with a separator described above, the reliability of the entire fuel cell stack is improved.

  According to the present invention, by controlling the shape of the deformation of the metal separator, the sealing portion is prevented from being damaged, thereby preventing peeling at the interface between the sealing portion and the metal separator. It is possible to provide a separator-equipped fuel cell and a fuel cell that have a longer life.

1 is a perspective view showing a solid oxide fuel cell 10. FIG. 1 is a schematic cross-sectional view of a solid oxide fuel cell 10. FIG. 3 is a cross-sectional view of a fuel cell 40. FIG. It is a disassembled perspective view showing the state which decomposed | disassembled the fuel cell main body 44 and the metal separator 53 (fuel cell 50 with a separator). It is sectional drawing showing the fuel cell 50 with a separator in manufacture. It is sectional drawing showing the fuel cell 50 with a separator in manufacture. It is sectional drawing showing the fuel cell 50 with a separator in manufacture. It is sectional drawing showing the fuel cell 50 with a separator in manufacture. It is sectional drawing showing the fuel cell 50 with a separator in manufacture. It is sectional drawing of the fuel cell 40a. It is a disassembled perspective view showing the state which decomposed | disassembled the fuel cell main body 44 and the metal separator 53 (fuel cell 50a with a separator). It is sectional drawing of the fuel battery cell 40b. It is a disassembled perspective view showing the state which decomposed | disassembled the fuel cell main body 44 and the metal separator 53 (fuel cell 50b with a separator).

  Hereinafter, a solid oxide fuel cell according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a perspective view showing a solid oxide fuel cell (fuel cell stack) 10 according to a first embodiment of the present invention. The solid oxide fuel cell 10 generates power by receiving supply of a fuel gas (for example, hydrogen) and an oxidant gas (for example, air (specifically, oxygen in the air)).

  In the solid oxide fuel cell 10, end plates 11 and 12, fuel cells 40 (1) to 40 (4) are laminated, bolts 21, 22 (22a, 22b), 23 (23a, 23b) and nuts 35. It is fixed with.

FIG. 2 is a schematic cross-sectional view of the solid oxide fuel cell 10.
The solid oxide fuel cell 10 is a fuel cell stack configured by stacking fuel cells 40 (1) to 40 (4). Here, for the sake of clarity, four fuel cells 40 (1) to 40 (4) are stacked, but in general, about 20 to 60 fuel cells 40 are often stacked. .

The end plates 11 and 12 and the fuel cells 40 (1) to 40 (4) have through holes 31 and 32 (32a and 32b) corresponding to the bolts 21 and 22 (22a and 22b) and 23 (23a and 23b), 33 (33a, 33b).
The end plates 11 and 12 are holding plates that press and hold the stacked fuel battery cells 40 (1) to 40 (4), and output current from the fuel battery cells 40 (1) to 40 (4). It is also a terminal.

  FIG. 3 is a cross-sectional view of the fuel battery cell 40. FIG. 4 is an exploded perspective view showing a state in which the fuel cell body 44 and the metal separator 53 (fuel cell with separator) are disassembled.

  As shown in FIG. 3, the fuel cell 40 is a so-called fuel electrode support membrane type fuel cell, and includes interconnectors 41 and 45, a current collector 42, and a frame part 43.

  The fuel cell main body 44 includes a solid electrolyte layer 56 sandwiched between an air electrode (also referred to as a cathode or an air electrode layer) 55 and a fuel electrode (also referred to as an anode or a fuel electrode layer) 57. An air electrode 55 and a fuel electrode 57 are arranged on the oxidant gas flow channel 47 side and the fuel gas flow channel 48 side of the solid electrolyte layer 56, respectively.

  As the air electrode 55, perovskite oxides (for example, LSCF (lanthanum strontium cobalt iron oxide), LSM (lanthanum strontium manganese oxide), various noble metals, and cermets of noble metals and ceramics can be used.

  For the solid electrolyte layer 56, materials such as YSZ (yttria stabilized zirconia), ScSZ (scandia stabilized zirconia), SDC (samarium doped ceria), GDC (gadolinium doped ceria), and perovskite oxide can be used.

  The fuel electrode 57 is preferably a metal, and Ni, Ni-ceramic cermets or Ni-based alloys can be used.

  The interconnectors 41 and 45 are plates having conductivity (for example, a metal such as stainless steel) that can secure conduction between the fuel cell main bodies 44 and prevent gas mixing between the fuel cell main bodies 44. Shaped member.

  In addition, only one interconnector (41 or 45) is disposed between the fuel cell main bodies 44 (one interconnector is shared between two fuel cell main bodies 44 connected in series). Because). Further, in each of the uppermost and lowermost fuel cell main bodies 44, conductive end plates 11 and 12 are disposed in place of the interconnectors 41 and 45, respectively.

The current collector 42 is for ensuring electrical continuity between the fuel cell main body 44 (air electrode 55) and the interconnector 41, and is made of, for example, a metal material such as a nickel alloy.
Further, the current collector 42 may have elasticity.

  The frame portion 43 has an opening 46 through which an oxidant gas and a fuel gas flow. The inside of the opening 46 is divided into an oxidant gas flow path 47 through which oxidant gas flows and a fuel gas flow path 48 through which fuel gas flows. Further, the frame portion 43 of this embodiment includes an air electrode frame 51, an insulating frame 52, a metal separator 53, and a fuel electrode frame 54.

  The air electrode frame 51 is a metal frame disposed on the air electrode 55 side, and has an opening 46 at the center. An oxidant gas flow path 47 is defined by the opening 46.

The insulating frame 52 is a frame that electrically insulates between the interconnectors 41 and 45. For example, ceramics such as Al ₂ O ₃ , mica, vermiculite, and the like can be used, and an opening 46 is provided at the center. An oxidant gas flow path 47 is defined by the opening 46. Specifically, the insulating frame 52 is disposed between the interconnectors 41 and 45 such that one surface contacts the air electrode frame 51 and the other surface contacts the metal separator 53. As a result, the interconnectors 41 and 45 are electrically insulated by the insulating frame 52.

  The metal separator 53 is a frame-shaped metal thin plate (for example, thickness: 0.1 mm) having an opening 58, is attached to the solid electrolyte layer 56 of the fuel cell main body 44, and has an oxidant gas. It is a metal frame that prevents mixing with fuel gas. The metal separator 53 divides the gap in the opening 46 of the frame portion 43 into an oxidant gas flow path 47 and a fuel gas flow path 48, thereby preventing mixing of the oxidant gas and the fuel gas.

  An opening 58 is formed in the metallic separator 53 by a through-hole penetrating between the upper surface and the lower surface of the metallic separator 53. The air electrode 55 of the fuel cell main body 44 is disposed in the opening 58. Further, the fuel cell main body 44 is joined and sealed in the opening 58. The fuel cell main body 44 to which the metallic separator 53 is joined is referred to as a “fuel cell with separator”. Details of this will be described later.

  Like the insulating frame 52, the fuel electrode frame 54 is an insulating frame disposed on the fuel electrode 57 side, and has an opening 46 in the center. A fuel gas flow path 48 is defined by the opening 46.

  Bolts 21, 22 (22a, 22b), 23 (23a, 23b) are inserted into the air electrode frame 51, the insulating frame 52, the metal separator 53, and the fuel electrode frame 54, or an oxidant gas or a fuel gas is inserted. The through holes 31, 32 (32a, 32b), 33 (33a, 33b) that circulate are provided in the respective peripheral portions.

(Details of fuel cell 50 with separator)
The separator-equipped fuel cell 50 according to the present embodiment includes a joining portion 61, a sealing portion 62, and a restraining portion 63. A joining portion 61 and a sealing portion 62 are disposed between the fuel cell main body 44 and the metal separator 53. Along the opening 58, the lower surface of the metallic separator 53 and the upper surface of the solid electrolyte layer 56 are joined by the joining portion 61 and sealed by the sealing portion 62. The restricting portion 63 is disposed on the upper surface of the metallic separator 53 corresponding to the sealing portion 62.

  The joining portion 61 is made of a brazing material containing Ag, and joins the fuel cell body 44 and the metal separator 53 along the opening 58 over the entire circumference. The joining portion 61 (Ag solder) has, for example, a width of 2 to 6 mm and a thickness of 10 to 80 μm.

As the material of the joining portion 61, various brazing materials mainly composed of Ag can be employed. For example, as a brazing material, a mixture of Ag and an oxide, for example, Ag-Al ₂ O ₃ (a mixture of Ag and Al ₂ O ₃ (alumina)) can be used. Examples of the mixture of Ag and oxide include Ag—CuO, Ag—TiO ₂ , Ag—Cr ₂ O ₃ , and Ag—SiO ₂ . Further, an alloy of Ag and another metal (for example, any one of Ag—Ge—Cr, Ag—Ti, and Ag—Al) can be used as the brazing material.

  The brazing material containing Ag (Ag brazing) is not easily oxidized at the brazing temperature even in an air atmosphere. For this reason, the fuel cell main body 44 and the metal separator 53 can be joined in an air atmosphere using Ag wax, which is preferable in terms of process efficiency.

The sealing portion 62 is disposed on the opening 58 side (inner peripheral side) of the joining portion 61 along the opening 58 over the entire circumference, and the oxidant gas in the opening 58 of the metallic separator 53 In order to prevent mixing with the fuel gas outside the opening 58, the space between the fuel cell main body 44 and the metal separator 53 is sealed. Since the sealing portion 62 is disposed on the opening 58 side of the joint portion 61, the joint portion 61 is not brought into contact with the oxidant gas, and oxygen from the oxidant gas flow path 47 side to the joint portion 61 is eliminated. Movement is prevented. As a result, it is possible to prevent a gas leak due to generation of a void in the junction 61 due to a reaction between hydrogen and oxygen. Furthermore, since the sealing portion 62 is disposed between the metallic separator 53 and the fuel cell main body 44, the thermal stress acting on the sealing portion 62 is not tensile stress but shear stress. For this reason, the sealing material becomes difficult to break, and peeling at the interface between the sealing portion 62 and the metal separator 53 or the fuel cell main body 44 can be suppressed, and the reliability of the sealing portion 62 can be improved.
The sealing part 62 has a width of 0.2 to 4 mm and a thickness of 10 to 80 μm, for example.

The restraining portion 63 is disposed over the entire circumference of the opening 58 on the main surface (front surface) of the metallic separator 53 at a position facing the sealing portion 62 with the metallic separator 53 interposed therebetween.
The restraining part 63 is made of a material having a larger thermal expansion coefficient than the constituent material (sealing material) of the sealing part 62.

  For this reason, when the solid oxide fuel cell 10 is used (about 700 ° C.), the metal separator 53 is curved toward the sealing portion 62 side, and a force is applied in the direction of pressing the sealing portion 62 (pressure contact). This prevents peeling at the interface between the sealing portion 62 and the metal separator 53 (decrease in sealing performance due to the sealing portion 62), and improves hermetic sealing performance.

  In addition, since the sealing portion 62 is disposed over the entire circumference of the opening 58, the constraining portion 63 is disposed over the entire circumference of the opening 58, so that the metal separator 53 is disposed over the entire circumference of the opening 58. Deformation can be suppressed.

Specifically, the sealing portion 62 and the restraining portion 63 can be made of a sealing material such as glass, glass ceramics (crystallized glass), or a composite of glass and ceramics.
The sealing part 62 is composed of a sealing material having a thermal expansion coefficient of 8 ppm / K or more and 12 ppm / K or less in a temperature range from room temperature to 300 ° C., and the restraining part 63 has a thermal expansion coefficient of 0 compared to the sealing material. .5 ppm / K to 2 ppm / K high constraining material.

The thermal expansion coefficient of the material constituting the restraining portion 63 may be smaller than the thermal expansion coefficient of the metallic separator 53.
Each of the metallic separator 53 and the restraining portion 63 is made of metal and glass, and the thermal expansion coefficient of the restraining portion 63 is usually smaller than that of the metallic separator 53. Even under such conditions, it is possible to suppress the deformation (bending) of the metallic separator 53 by the restricting portion 63.

  The metal separator 53 uses an Al-added ferrite SUS material such as SUH21 (18Cr-3Al) from the viewpoint of oxidation resistance durability. Therefore, the thermal expansion coefficient of the metallic separator 53 is 10 to 14 ppm / K in the temperature range from room temperature to 300 ° C. Since the sealing material is weak against tensile stress and easily cracked, but is strong against compressive stress, it is preferable that the thermal expansion coefficient of the sealing material is lower than that of the metallic separator 53. Specifically, the temperature is from room temperature to 300 ° C. Within the range, it is preferably 8 ppm / K or more and 12 ppm / K or less.

(Manufacturing method of fuel cell 50 with separator)
Below, the manufacturing method of the fuel cell 50 with a separator is demonstrated. 5A to 5E are cross-sectional views showing the separator-equipped fuel cell 50 being manufactured.

  First, for example, a plate material made of SUH 21 was punched out to manufacture a metal separator 53 having an opening 58. In addition, a sheet of the solid electrolyte layer 56 was attached to one surface of the green sheet of the fuel electrode 57 to form a laminate, and the laminate was fired once. Thereafter, the material of the air electrode 55 was printed and fired to prepare the fuel cell main body 44.

The brazing materials 611 and 612 are disposed on the fuel cell main body 44 and the metal separator 53, respectively (see FIG. 5A). For example, a brazing material containing paste-like Ag is printed in a predetermined shape on the upper surface of the solid electrolyte layer 56 of the fuel cell body 44 and the lower surface of the metal separator 53, so that the fuel cell body 44 and the metal separator 53 respectively. The brazing materials 611 and 612 are disposed on the surface. As a method for arranging the brazing materials 611 and 612, in addition to the above, a dispenser may be used.
For example, the brazing materials 611 and 612 have a width of 2 to 6 mm and a thickness of 10 to 80 μm.

Next, a sealing material 621 is disposed on the upper surface of the solid electrolyte layer 56 of the fuel cell main body 44 (see FIG. 5B). For example, the sealing material 621 can be disposed on the upper surface of the solid electrolyte layer 56 of the fuel cell main body 44 by printing a paste containing glass as the sealing material. In addition, as a method of arranging the sealing material 621, a dispenser may be used in addition to the above. The sealing material 621 may be printed on the lower surface of the metal separator 53.
The sealing material 621 has, for example, a width of 0.2 to 4 mm and a thickness of 10 to 80 μm.

  The brazing materials 611 and 612 and the sealing material 621 are melted, and the fuel cell main body 44 and the metal separator 53 are joined (formation of the joining portion 61), and simultaneously, the sealing portion 62 is formed (see FIG. 5C). The fuel cell body 44 on which the brazing materials 611 and 612 are disposed and the metal separator 53 are brought into contact with each other and heated at, for example, 850 to 1100 ° C., so that the brazing materials 611 and 612 are melted and the fuel cell body 44 And the metal separator 53 were joined. At this time, the sealing material 621 is also melted at the same time, and the fuel cell main body 44 and the metal separator 53 are sealed (formation of the sealing portion 62).

A constraining material 631 having a thermal expansion higher than that of the sealing material 621 by 0.5 ppm / K to 2 ppm / K is disposed on the metal separator 53 (see FIG. 5D). For example, the restraint material 631 can be disposed at a predetermined position by printing a paste containing glass as the restraint material 631 on the upper surface of the metal separator 53. As a method of arranging the restraining material 631, other than the above, a dispenser may be used.
The restraining material 631 has, for example, a width of 0.2 to 4 mm, a thickness of 10 to 200 μm, and is thicker than the sealing material 621.

  The sealing material 621 and the restraining material 631 are melted to form the restraining portion 63 (see FIG. 5E). The restraint material 631 is heated by heating the fuel cell body 44 and the metal separator 53, which are joined at the joint portion 61, the sealing portion 62, and the restraint material 631 are disposed at 850 to 1100 ° C., for example. Is melted, and the restraint portion 63 is formed.

  Through the above steps, the separator-equipped fuel cell 50 (the fuel cell main body 44 to which the metal separator 53 was joined) of this example was produced.

(Method for producing solid oxide fuel cell (fuel cell stack) 10)
For example, the air electrode frame 51 and the fuel electrode frame 54 are manufactured by punching a plate material made of SUH 21 into a predetermined shape. On the other hand, the end plates 11 and 12 and the interconnectors 41 and 45 are manufactured by punching a plate made of, for example, Hitachi Metals ZMG232 into a predetermined shape. The insulating frame 52 is manufactured by processing a plate material made of mica, for example.

  On the air electrode 55 side of the fuel cell main body 44 of the fuel cell 50 with a separator produced by the manufacturing method described above, the insulating frame 52, the air electrode frame 51, and the interconnector 41 are arranged on the metal separator 53 in this order. On the fuel electrode 57 side, the fuel electrode frame 54 and the interconnector 45 were arranged in this order, and the fuel cell 40 was manufactured.

  A plurality of fuel cells 40 are stacked, end plates 11 and 12 are arranged on the uppermost layer and the lowermost layer, and the plurality of fuel cells 40 are sandwiched between the end plates 11 and 12 by bolts 21 to 23 and nuts 35. The solid oxide fuel cell 10 was prepared by fixing.

(Second Embodiment)
A second embodiment will be described. FIG. 6 is a cross-sectional view of a fuel battery cell 40a according to the second embodiment. FIG. 7 is an exploded perspective view showing a state in which the fuel cell body 44 and the metal separator 53 (the separator-equipped fuel cell 50a) according to the second embodiment are disassembled.

  The fuel cell 40 a has a connecting portion 64 disposed on the side surface of the opening 58. That is, the sealing portion 62a and the restraining portion 63a are connected by the connecting portion 64 and are integrally formed. Since the sealing portion 62a and the restraining portion 63a are integrated, the restraining force is further increased, and deformation (deflection) of the metal separator 53 can be further suppressed.

  As described above, the restraining portion 63a is made of a material having a thermal expansion coefficient larger than that of the constituent material (sealing material) of the sealing portion 62a, and sandwiches the metal separator 53 together with the sealing portion 62a. For this reason, when the solid oxide fuel cell 10 is used, the metal separator 53 is curved toward the sealing portion 62 side, and a force acts in a direction in which the sealing portion 62 is pressed (pressure contact). This force suppresses peeling at the interface between the sealing portion 62 and the metal separator 53 (decrease in sealing performance due to the sealing portion 62), and the hermetic sealing performance is improved.

  In addition to the upper and lower sides of the metal separator 53 along the opening 58, a connecting portion 64 composed of the sealing material 621 or the restraining material 631 is arranged on the side surface of the opening 58, so that the metal separator 53 is arranged. Is effectively prevented. In other words, the sealing portion 62a, the restraining portion 63a, and the connecting portion 64 hold the metal separator 53 and fix the metal separator 53, thereby further suppressing peeling at the interface between the sealing portion 62a and the metal separator 53. Is done.

  Further, the integration of the sealing portion 62a and the restraining portion 63a contributes to a substantial increase in the width of the sealing portion 62a, and the reliability of sealing by the sealing portion 62a is improved. As described above, the sealing portion 62 a prevents the oxidant gas from moving from the oxidant gas flow path 47 to the joint portion 61. By integrating the sealing portion 62a and the restraining portion 63a, the length (width, seal path) of the sealing portion 62a on the path from the oxidant gas flow path 47 to the joint portion 61 is increased. As a result, the reliability of sealing by the sealing portion 62a is further improved.

  In FIG. 6, the connecting portion 64 is made of the same material as the constituent material of the restraining portion 63a. However, the connecting portion 64 can be made of the same material as the constituent material of the sealing portion 62a. Even if such a configuration is used, the sealing portion 62a and the metal are made as compared with the case where the connecting portion 64 is not provided. The reliability of sealing can be improved by suppressing peeling at the interface with the separator 53 and increasing the seal path.

As can be seen, the boundary between the constituent materials of the sealing portion 62 a and the restraining portion 63 a is allowed to vary to some extent in the thickness direction of the metallic separator 53.
Moreover, in this embodiment, the boundary of the constituent material of the sealing part 62a and the restraint part 63a is comparatively clear, and the component is changing discontinuously at this boundary. On the other hand, it is allowed that the component continuously changes at the boundary between the constituent materials of the sealing portion 62a and the restraining portion 63a, and accordingly the boundary becomes unclear (blurred).

(Modification of the second embodiment)
A modification of the second embodiment will be described. FIG. 8 is a cross-sectional view of a fuel battery cell 40b according to a modification of the second embodiment. FIG. 9 is an exploded perspective view showing a state in which the fuel cell body 44 and the metal separator 53 (separator-equipped fuel cell 50b) according to a modification of the second embodiment are disassembled.

  In the fuel cell 40b, a gap (space) 65 is provided between the joint portion 61 and the sealing portion 62b. As described above, even if the joining portion 61 and the sealing portion 62b are not in contact with each other, it is possible to suppress the deformation (bending) of the metal separator 53 at the portion covering the sealing portion 62b.

In the fuel cells 40 a and 40 b, the joint portion 61 and the sealing portions 62 a and 62 b are in contact with each other over the entire circumference of the opening 58 or have a gap 65. As an intermediate aspect thereof, the joining portion 61 and the sealing portions 62a and 62b are in contact with each other at a part of the periphery of the opening portion 58, and the joining portion 61 and the sealing portion 62b are in contact with each other at a part of the periphery of the opening portion 58. It is also possible not to.
Further, a gap (space) 65 may be provided between the joining portion 61 and the sealing portion 62b in a state where the connecting portion 64 is not provided as in the fuel battery cell 40.

(Other embodiments)
Embodiments of the present invention are not limited to the above-described embodiments, and can be expanded and modified. The expanded and modified embodiments are also included in the technical scope of the present invention.

  In the above embodiment, the metal separator 53 is joined to the upper surface (the air electrode 55 side) of the solid electrolyte layer 56 in order to be applied to an anode-supported fuel cell. On the other hand, for example, in the solid electrolyte support type and the cathode support type, the metal separator 53 may be bonded to the lower surface (the fuel electrode 57 side) of the solid electrolyte layer 56. In this case, the fuel electrode 57 is formed smaller than the solid electrolyte layer 56 and disposed in the opening 58 so as not to be exposed to the oxidant gas.

10 Solid oxide fuel cell 11, 12 End plate 21-23 Bolt 31, 32 Through hole 35 Nut 40 Fuel cell 41, 45 Interconnector 42 Current collector 43 Frame 44 Fuel cell main body 46 Opening 47 Oxidant gas Flow path 48 Fuel gas flow path 50 Fuel cell with separator 51 Air electrode frame 52 Insulation frame 53 Metal separator 54 Fuel electrode frame 55 Air electrode 56 Solid electrolyte layer 57 Fuel electrode 58 Opening 61 Joints 611, 612 Brazing material 62 Sealing part 621 Sealing material 63 Restraining part 631 Restraining material 64 Connecting part 65 Gap

Claims (7)

A fuel cell body configured by sandwiching a solid electrolyte layer between an air electrode and a fuel electrode;
A plate-like metal separator having an opening opening in the main surface and the back surface, the back surface side being attached to the fuel cell body through a bonding portion made of a bonding material containing Ag;
A fuel cell with a separator, comprising:
A sealing part that is disposed over the entire periphery of the opening part on the opening part side of the joining part and between the back surface of the metallic separator and the cell body, and includes a sealing material including glass;
A constraining portion made of a material having a thermal expansion coefficient larger than that of the sealing material, disposed on the metal separator main surface at a position facing the sealing portion with the metal separator interposed therebetween;
A fuel cell with a separator, comprising: The fuel cell with a separator according to claim 1, wherein the restraining portion is disposed over the entire circumference of the opening. The sealing portion and the restraining portion are integrally formed by a connecting portion disposed on the side surface of the opening of the metal separator.
The separator-equipped fuel cell according to claim 1 or 2. The thermal expansion coefficient of the material constituting the restraint is smaller than the thermal expansion coefficient of the metal separator.
The separator-equipped fuel cell according to any one of claims 1 to 3. Having a gap between the joint and the sealing portion;
The fuel cell with a separator according to any one of claims 1 to 4, wherein the fuel cell has a separator. The thermal expansion coefficient of the sealing material is 8 ppm / K or more and 12 ppm / K or less in a temperature range from room temperature to 300 ° C.,
The separator-equipped fuel cell according to any one of claims 1 to 5. A fuel cell with a separator according to any one of claims 1 to 6,
A fuel cell comprising:

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