JP6118230B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack.

  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.

  In fuel cells, it is efficient to prevent leakage of supply gas (either fuel gas and / or oxidant gas) and to ensure uniform supply to electrodes (either or both of fuel electrode and air electrode). Important for power generation.

  Here, a technique of brazing an alloy holding thin plate frame (corresponding to the separator) to a flat cell (corresponding to the fuel cell) or sealing with a glass-based sealant is disclosed. (See Patent Document 1). In addition, a technique is disclosed in which ribs serving as fuel flow barriers are provided at the inlets and outlets of a plurality of parallel flow paths to increase the flow uniformity of the parallel flow paths (see Patent Document 2).

JP 2000-331692 A JP 2009-070651 A

However, in the techniques of Patent Documents 1 and 2, it is not always easy to prevent the supply gas from leaking and to ensure uniform supply to the electrodes.
During the operation of the fuel cell, hydrogen on the fuel electrode side and oxygen on the air electrode side diffuse and react in the brazing material to generate voids, which may cause gas leakage.
Further, as in Patent Document 2, providing ribs requires complicated processing of members, which may require time and cost.
An object of the present invention is to provide a fuel cell stack in which power generation efficiency is improved by preventing leakage of supply gas and uniform supply to electrodes.

(1) A fuel cell stack according to the present invention comprises:
A first interconnector and a second interconnector;
A first main surface disposed between the interconnectors and facing the first interconnector, a second main surface facing the second interconnector, and between the first main surface and the second main surface. A plate-shaped metal separator having a through hole;
An air electrode, a fuel electrode, and a solid electrolyte layer disposed between the air electrode, the fuel electrode, and the solid electrolyte layer between the first interconnector and the first main surface. Any one of the electrodes is disposed in the through hole in a plan view, and the electrode has a pair of sides along a direction from the gas inflow portion toward the gas outflow portion;
Joining the fuel cell single cell body and the first main surface of the metallic separator, and made of a brazing material containing Ag;
A sealing portion that is disposed over the entire circumference of the through-hole between the fuel cell single cell main body and the first main surface on the side of the through-hole with respect to the joint, and has a sealing material containing glass; ,
A gas inflow portion for allowing a supply gas of either an oxidant gas or a fuel gas to flow between the second main surface and the second interconnector;
A gas outflow part that flows in between the second main surface and the second interconnector from the gas inflow part and outflows the supply gas that has passed over the surface of the electrode;
On the second main surface of the metallic separator at a position facing the sealing portion with the metallic separator in between, the gas inflow portion is disposed, and the same material as the sealing material or the A constrained portion made of a material having a larger coefficient of thermal expansion than the encapsulant;
Between the second main surface and the second interconnector, facing each other, the flow of the supply gas flowing in from the gas inflow portion over the restraint portion and flowing out from the gas outflow portion is A pair of flow restriction portions disposed along each of the pair of sides so as to restrict a range along a direction from the gas inflow portion toward the gas outflow portion;
It is characterized by comprising.

  In the present invention, “a joined portion made of a brazing material containing Ag, which joins the fuel cell single cell body and the first main surface of the metal separator,” and “a portion closer to the through hole than the joined portion, By providing a sealing part having a sealing material including glass between the fuel cell single cell body and the first main surface, the gas supplied to the fuel cell stack is provided. Leakage that leaks can be reduced.

  During the operation of the fuel cell, hydrogen on the fuel electrode side and oxygen on the air electrode side may diffuse and react in the joint and generate voids in the joint. On the other hand, the sealing part containing glass can prevent the supply gas from reaching the joining part (the brazing material) and prevent the generation of voids in the brazing material. In addition, since the joint (brazing material) is present, the stress applied to the sealing portion is only a part of the stress between the fuel cell single cell main body and the metal separator, so that sealing including glass is performed. The crack which a part cracks is reduced. Further, since the restraint portion is present, the metal separator is prevented from warping from the fuel cell single cell main body, so that the cracking of the sealing portion containing glass is further reduced.

Further, “a flow of a supply gas which is disposed between the second main surface and the second interconnector so as to face each other and flows in from the gas inflow portion over the restraint portion and out of the gas outflow portion. Is provided with a pair of flow restricting portions arranged along each of the pair of sides so as to restrict a range along the direction from the gas inflow portion toward the gas outflow portion. And uniform supply of the supply gas to any one of the fuel electrodes) and power generation efficiency can be improved.
In other words, the supply gas flows over the electrode over the restriction part, so that the restriction part functions as a kind of dam, and the supply gas is easily supplied uniformly on the electrode (distribution of supply gas). In addition, since the pair of flow restricting portions restrict the escape of the supply gas to the outside of the electrode, an efficient and uniform supply of the supply gas is ensured, and the power generation efficiency can be improved.

  Here, since the sealing portion and the restraining portion have functions of sealing and distributing the supply gas, both prevention of supply gas leakage and uniform supply of the supply gas can be realized with a simple configuration.

  As described above, in the present invention, it is possible to prevent leakage of the supply gas and to supply the electrode uniformly with a relatively simple configuration using the sealing portion, the restraining portion, and the flow restriction portion, thereby improving the power generation efficiency. Can be achieved.

(2) The restraining portion may be arranged over the entire circumference of the through hole.
By disposing the restraining portion over the entire circumference of the through hole, it is possible to prevent damage to the sealing portion over the entire circumference of the through hole, and to improve the supply gas supply uniformity in the through hole (on the electrode).

(3) The sealing portion and the restraining portion may be connected by a connecting portion disposed on an inner surface of the through hole of the metal separator.
When the sealing portion and the restraining portion are connected and integrated, it contributes to a substantial increase in the width of the sealing portion, and the sealing performance by the sealing portion is improved.

(4) The flow restricting portion may include any one of ceramic felt, mica, and vermiculite.
Since these materials have heat resistance and flexibility, the supply gas escapes from the gap between the flow restricting portion and the restraining portion by being deformed according to the shape of the restraining portion in the vicinity of the electrode that is at a high temperature. Can be prevented.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell stack which aimed at the improvement of electric power generation efficiency by prevention of the leak of supply gas and the uniform supply to an electrode can be provided.

1 is a perspective view showing a solid oxide fuel cell 10. FIG. 1 is a schematic cross-sectional view in the Y direction of a solid oxide fuel cell 10. FIG. 1 is a schematic cross-sectional view in the X direction 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 single cell main body 44 and the metal separator 53 (fuel cell 50 with a separator). It is sectional drawing of the fuel cell 40a. It is a disassembled perspective view showing the state which decomposed | disassembled the fuel cell single cell main body 44 and the metal separator 53 (fuel cell 50a 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 and fuel cells 40 (1) to 40 (4) are stacked, and bolts 21, 22 (22 a, 22 b), 23 (23 a, 23 b) and nuts 35 are stacked. It is fixed with.

  The bolts 22 (22a, 22b) and 23 (23a, 23b) have a cavity functioning as a flow path for fuel gas or oxidant gas (supply gas) inside or outside. Here, cavities functioning as flow paths for the supply gas are arranged inside the bolts 22 and 23. On the other hand, it is good also as a flow path of supply gas between the outer periphery of the volt | bolts 22 and 23 and the through-holes 32 and 33. FIG.

  Bolts 22a and 22b supply and discharge oxidant gas to and from the fuel cell 40, respectively. The bolts 23a and 23b supply and discharge the fuel gas to and from the fuel cell 40, respectively.

2 and 3 are schematic cross-sectional views of the solid oxide fuel cell 10 in the Y direction and the X direction, respectively.
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. 4 is a cross-sectional view of the fuel battery cell 40. FIG. 5 is an exploded perspective view showing a state in which the fuel cell single cell main body 44 and the metal separator 53 (fuel cell with separator) are disassembled.

  As shown in FIG. 4, the fuel cell 40 includes a so-called fuel electrode supporting membrane type fuel cell single cell main body 44, interconnectors 41 and 45, current collectors 42 a and 42 b, and a frame portion 43.

  The fuel cell single cell main body 44 is configured by sandwiching a solid electrolyte layer 56 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.

  The fuel gas flows into the fuel gas flow channel 48 from the gas inflow portion I1 through the fuel gas flow passage (a cavity disposed inside or outside the bolt 23a) of the bolt 23a, and from the gas outflow portion O1 to the bolt 23b. It flows out to the fuel gas flow path.

  The oxidant gas flows into the oxidant gas flow path 47 from the gas inflow part I2 through the oxidant gas flow path of the bolt 22a (a cavity disposed inside or outside the bolt 22a), and from the gas outflow part O2. It flows out to the oxidant gas flow path of the bolt 22b.

  The air electrode 55 is disposed in the through hole 58 as viewed from above (in plan view). The air electrode 55 has a rectangular flat plate shape and has a pair of sides 55a along the direction from the gas inflow portion I2 toward the gas outflow portion O2.

  As the air electrode 55, a perovskite oxide (for example, LSCF (lanthanum strontium cobalt iron oxide), LSM (lanthanum strontium manganese oxide) 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 have conductivity (for example, a metal such as stainless steel) that can secure conduction between the fuel cell single cell bodies 44 and prevent gas mixing between the fuel cell single cell bodies 44. It is a plate-shaped member.

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

  The current collector 42 a is for ensuring electrical connection between the air electrode 55 of the fuel cell single cell main body 44 and the interconnector 41, and is, for example, a convex portion formed in the interconnector 41. The current collector 42b is for ensuring electrical continuity between the fuel electrode 57 of the fuel cell single cell main body 44 and the interconnector 41. For example, a nickel felt or a nickel mesh having air permeability is used. it can.

  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 a through hole 58, is attached to the solid electrolyte layer 56 of the fuel cell single cell main body 44, and is an oxidant gas. It is a metal frame which 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.

  A through-hole 58 is formed in the metal separator 53 by a through-hole penetrating between the upper surface (second main surface) and the lower surface (first main surface) of the metal separator 53. The air electrode 55 of the fuel cell single cell main body 44 is disposed in the through hole 58. In addition, the fuel cell single cell main body 44 is joined and sealed around the through hole 58. The fuel cell single cell body 44 to which the metal 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, a restraining portion 63, and a flow restricting portion 71. A joining portion 61 and a sealing portion 62 are arranged between the fuel cell single cell main body 44 and the metal separator 53. Along the through hole 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 single cell main body 44 and the lower surface (first main surface) of the metal separator 53 along the through hole 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 single 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 through hole 58 side (inner peripheral side) with respect to the entire circumference of the through hole 58 along the through hole 58, and the oxidant gas in the through hole 58 of the metal separator 53. In order to prevent mixing with the fuel gas outside the through hole 58, the space between the fuel cell single cell main body 44 and the lower surface (first main surface) of the metal separator 53 is sealed. Since the sealing portion 62 is disposed closer to the through hole 58 than the joint portion 61, the joint portion 61 is not in 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.

Further, since the sealing portion 62 is disposed between the metal separator 53 and the fuel cell single cell main body 44, the thermal stress acting on the sealing portion 62 is not a tensile stress but a shear stress. For this reason, the sealing material is hardly broken, and peeling at the interface between the sealing portion 62 and the metal separator 53 or the fuel cell single 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 0.05 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 through hole 58 on the upper surface (second main surface) of the metallic separator 53 at a position facing the sealing portion 62 with the metallic separator 53 interposed therebetween.
The restricting portion 63 is made of the same material as the constituent material (sealing material) of the sealing portion 62 or a material having a thermal expansion coefficient larger than that of the sealing material.

  When the restraint part 63 is made of a material having a thermal expansion coefficient larger than that of the sealing material, the metal separator 53 is used when the solid oxide fuel cell 10 is used (about 700 ° C.). Curved to the 62 side, a force acts in the direction of pressing the sealing portion 62 (pressure contact), peeling at the interface between the sealing portion 62 and the metal separator 53 (decrease in sealing performance by the sealing portion 62) ), And hermetic sealing is improved.

  In addition, since the sealing portion 62 is disposed over the entire circumference of the through hole 58, the metal separator 53 is disposed over the entire circumference of the through hole 58 by arranging the restraining portion 63 over the entire circumference of the through hole 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.

  The pair of flow restricting portions 71 are connected to each other along the pair of sides 55a of the air electrode 55 between the upper surface (second main surface) of the metallic separator 53 and the upper surface of the solid electrolyte layer 56 and the interconnector 41. Opposed to each other.

  As shown in FIG. 5, the oxidant gas (G) flows from the gas inflow part I2 over the restraint part 63 into the oxidant gas flow path 47, passes over the air electrode 55 (electrode), and again. It flows out to the gas outflow part O2 over the restraint part 63.

  At this time, the uniform supply of the oxidant gas (supply gas) to the air electrode 55 is facilitated as follows, and the power generation efficiency can be improved. That is, the oxidant gas (G) supplied from the gas inflow portion I2 is distributed by the restraining portion 63 in the direction perpendicular to the gas flow direction in plan view, and then flows out onto the air electrode 55 (electrode surface) (dam). effect). In addition to this, the pair of flow restricting portions 71 flows from the gas inflow portion I2 through the restricting portion 63 and flows the oxidant gas (supply gas) flowing out from the gas outflow portion O2 from the gas inflow portion to the gas. Limit to the range along the direction toward the outflow.

That is, the oxidant gas flows over the restraint portion 63 and onto the air electrode 55 (electrode), so that the restraint portion 63 functions as a kind of dam, and it becomes easy to uniformly supply the supply gas onto the air electrode 55. (Distribution of supply gas). In addition, since the pair of flow restricting portions 71 restricts the escape of the oxidant gas to the outside of the air electrode 55, efficient and uniform supply of the oxidant gas is ensured, and the power generation efficiency can be improved.
In particular, since the sealing portion 62 and the restraining portion 63 each have a function of sealing and distributing the oxidant gas, both the prevention of the oxidant gas leakage and the uniform supply of the oxidant gas can be achieved with new members. It can be realized with a simple configuration without any additional processing.
In addition, since the restricting portion 63 is arranged over the entire circumference of the through hole 58, the supply gas supply uniformity in the through hole 58 (on the electrode) is improved.

  The flow restricting unit 71 can be composed of any one of ceramic felt, mica, and vermiculite. Since these materials have heat resistance and flexibility, the material is deformed in the vicinity of the air electrode 55 that is at a high temperature according to the shape of the restraining portion 63 and the like, so that the gap between the flow restricting portion 71 and the restraining portion 63 etc. Oxidant gas (supply gas) can be prevented from escaping.

  As described above, the solid oxide fuel cell 10 has a relatively simple configuration using the sealing portion 62, the restraining portion 63, and the flow restricting portion 71, and prevents the supply gas from leaking and uniformly supplying the electrodes. Power generation efficiency can be improved.

(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 single cell main 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 through hole 58. That is, the sealing portion 62a and the restraining portion 63a are connected by the connecting portion 64 and are integrally formed.

  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 the present embodiment, the boundary between the constituent materials of the sealing portion 62a and the restraining portion 63a is relatively clear, and the components change 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).

(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 flow restricting portion 71 is disposed on the air electrode 55 side, and the uniformity of the supply of the oxidant gas to the air electrode 55 is maintained. On the other hand, the flow restricting portion 71 may be arranged on the fuel electrode 57 side to maintain the uniformity of the supply of the fuel gas to the fuel electrode 57. That is, the restricting portion 71 can be disposed on one or both of the air electrode 55 side and the fuel electrode 57 side.

10 Solid oxide fuel cells 11, 12 End plates 21 (22a, 22b), 22 (22a, 22b), 23 (23a, 23b) Bolts 31, 32 Through hole 35 Nut 40 Fuel cell 41, 45 Interconnector 42a , 42b Current collector 43 Frame 44 Fuel cell single cell body 46 Opening 47 Oxidant gas flow path 48 Fuel gas flow path 50 Fuel cell with separator 51 Air electrode frame 52 Insulating frame 53 Metal separator 54 Fuel electrode frame 55 Air Electrode 55a Side 56 Solid electrolyte layer 57 Fuel electrode 58 Through-hole 61 Junction part 62 Sealing part 62a Sealing part 63 Restraint part 64 Connection part 71 Flow restriction part I1, I2 Gas inflow part O1, O2 Gas outflow part

Claims (4)

A first interconnector and a second interconnector;
A first main surface disposed between the interconnectors and facing the first interconnector, a second main surface facing the second interconnector, and between the first main surface and the second main surface. A plate-shaped metal separator having a through hole;
An air electrode, a fuel electrode, and a solid electrolyte layer disposed between the air electrode, the fuel electrode, and the solid electrolyte layer between the first interconnector and the first main surface. A fuel cell single cell body , in which any one of the electrodes is disposed in the through hole in plan view;
Joining the fuel cell single cell body and the first main surface of the metallic separator, and made of a brazing material containing Ag;
A sealing portion that is disposed over the entire circumference of the through-hole between the fuel cell single cell main body and the first main surface on the side of the through-hole with respect to the joint, and has a sealing material containing glass; ,
A gas inflow portion for allowing a supply gas of either an oxidant gas or a fuel gas to flow between the second main surface and the second interconnector;
A gas outflow part that flows in between the second main surface and the second interconnector from the gas inflow part and outflows the supply gas that has passed over the surface of the electrode;
On the second main surface of the metallic separator at a position facing the sealing portion with the metallic separator in between, the gas inflow portion is disposed, and the same material as the sealing material or the A constrained portion made of a material having a larger coefficient of thermal expansion than the encapsulant;
A fuel cell stack comprising:
The electrode has a pair of sides along a direction from the gas inflow portion to the gas outflow portion,
The gas inflow portion and the gas outflow portion are arranged on the outer peripheral side with respect to the through hole and the restraint portion in a plan view,
The fuel cell stack is further disposed between the second main surface and the second interconnector so as to face each other, and flows in from the gas inflow portion over the restraint portion and from the gas outflow portion. A pair of flow restricting portions arranged along each of the pair of sides so as to restrict a flow of the supply gas flowing out to a range along a direction from the gas inflow portion toward the gas outflow portion; A fuel cell stack characterized by The restraining portion is disposed over the entire circumference of the through hole;
The fuel cell stack according to claim 1. The sealing portion and the restraining portion are connected by a connecting portion disposed on the inner surface of the through hole of the metallic separator.
The fuel cell stack according to claim 1 or 2, wherein The flow restricting portion includes one of ceramic felt, mica, and vermiculite,
The fuel cell stack according to any one of claims 1 to 3, wherein

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