JP7611181B2 - Complex - Google Patents

Description

The technology disclosed in this specification relates to a composite.

One type of fuel cell that generates electricity using an electrochemical reaction between hydrogen and oxygen is a solid oxide fuel cell (hereinafter referred to as "SOFC") that has an electrolyte layer containing a solid oxide. A single fuel cell (hereinafter simply referred to as "single cell"), which is the constituent unit of an SOFC, includes an electrolyte layer, and an air electrode and a fuel electrode that face each other in a specific direction (hereinafter referred to as the "first direction") across the electrolyte layer.

SOFCs are generally used in the form of a fuel cell stack that includes a power generation block in which a plurality of power generation units each having a single cell are arranged in a first direction, and in which a manifold is formed that communicates with a gas chamber that faces a specific electrode, which is one of the fuel electrode and the air electrode. The fuel cell stack further includes an end member, a gas passage member, and a joint member. The end member is disposed on one side of the power generation block in the first direction. The end member has an end through hole that penetrates in the first direction and communicates with the manifold. The gas passage member is disposed on the one side of the end member in the first direction (the side opposite the power generation block). The gas passage member is a cylindrical body that penetrates in the first direction and has a gas through hole that communicates with the end through hole. The joint member is disposed between the power generation block and the end member (see, for example, Patent Document 1).

JP 2017-10804 A

The inventors of the present application have studied a fuel cell stack including an end member having an erected portion. The erected portion is cylindrical and protrudes to the one side in the first direction and surrounds the end through-hole. The gas passage member is connected to the erected portion of the end member. In this configuration, when an external force is applied to the gas passage member and it is displaced, the connection periphery portion of the end member, which is the portion that surrounds the outline of the connection portion between the erected portion and the gas passage member, is likely to deform. Here, if the joining member is arranged in a position that overlaps with the connection periphery portion of the end member when viewed in the first direction, there is a problem that the deformation of the connection periphery portion applies stress to the joining member, which may damage the joint portion of the joining member.

The above problem is also common to electrolysis cell stacks that include multiple electrolysis cell units, including electrolysis unit cells, which are the constituent units of solid oxide electrolysis cells (hereinafter referred to as "SOECs") that generate hydrogen by utilizing the electrolysis reaction of water. In this specification, the fuel cell unit cell and the electrolysis unit cell are collectively referred to as electrochemical reaction unit cells, the fuel cell power generation unit and the electrolysis cell unit are collectively referred to as electrochemical reaction unit cells, and the fuel cell stack and the electrolysis cell stack are collectively referred to as electrochemical reaction cell stacks. In addition, such a problem is not limited to SOFCs and SOECs, but is also common to other types of fuel cells and electrolysis cells. Furthermore, such a problem is not limited to electrochemical reaction cell stacks, but is also common to a composite that includes a first member having a first through hole and a standing portion, a cylindrical member connected to the standing portion, a second member, and a joining member that joins the first member and the second member.

This specification discloses a technology that can solve the above-mentioned problems.

The technology disclosed in this specification can be realized, for example, in the following forms:

(1) The composite disclosed in the present specification includes a first member having a first through hole penetrating in a first direction and a cylindrical standing portion protruding to one side in the first direction and surrounding the first through hole, a cylindrical member connected to the standing portion so as to communicate with the first through hole of the first member, a second member arranged on the other side of the first direction relative to the first member, and a joining member arranged between the first member and the second member and arranged around the first through hole as viewed in the first direction, in which the joining member is arranged outside the connection periphery of the first member, which is a portion of the cylindrical member that surrounds the outline of the connection portion with the standing portion. In this composite, the joining member is arranged outside the connection periphery of the first member, which is a portion of the cylindrical member that surrounds the outline of the connection portion with the standing portion of the first member. Therefore, even if the connection periphery of the first member is deformed due to the displacement of the tubular member, the deformation is not easily transmitted to the joining member. As a result, this composite can prevent damage to the joints of the joining members caused by the displacement of the tubular member.

(2) In the above composite, the second member may be arranged adjacent to the first member on the other side in the first direction. In this composite, a joining member is arranged between the first member and the second member adjacent thereto. Even in such a configuration in which the joining member is arranged in a position close to the deformation location of the first member, by applying the present invention, it is possible to prevent damage to the joint location of the joining member due to the displacement of the tubular member.

(3) In the above composite, the rigidity of the overlapping portion of the first member that overlaps with the joining member when viewed in the first direction may be higher than the rigidity of the peripheral connection portion. With this composite, even if the peripheral connection portion of the first member is deformed, the overlapping portion of the first member is less likely to deform. Therefore, the deformation of the first member is prevented from being transmitted to the joining member, and damage to the joint portion of the joining member due to the displacement of the tubular member can be effectively prevented.

(4) In the above composite, the joining member may be configured such that a second through hole is formed surrounding the periphery of the first through hole when viewed in the first direction, and the separation distance between the joining member and the joining portion of the tubular member is different from each other on at least two imaginary straight lines extending in different directions from the center of the space surrounded by the outline of the joining portion of the tubular member when viewed in the first direction. According to this composite, for example, when the tubular member is displaced in the direction in which the separation distance is longer, damage to the joint by the joining member can be effectively suppressed.

(5) In the above composite, the composite may be an electrochemical reaction block composed of a plurality of electrochemical reaction units arranged in the first direction, each of the electrochemical reaction units having an electrochemical reaction unit cell including an electrolyte layer and an air electrode and a fuel electrode facing each other in the first direction with the electrolyte layer sandwiched therebetween, the electrochemical reaction block is arranged on the other side of the first direction with respect to the first member, the second member is arranged between the electrochemical reaction block and the first member, and a manifold for exchanging gas between at least one of the air electrode and the fuel electrode in each of the electrochemical reaction units is formed so as to extend from the inside of the electrochemical reaction block to the cylindrical member through the first through hole of the first member. In this electrochemical reaction cell stack, the joining member is arranged outside the connection periphery, which is the portion of the cylindrical member that surrounds the outline of the connection portion with the end member. Therefore, even if the connection periphery of the end member is deformed due to the displacement of the cylindrical member caused by an external force, the deformation is not easily transmitted to the joining member. As a result, with this electrochemical reaction cell stack, it is possible to suppress damage to the joints of the joining members caused by the displacement of the cylindrical member.

The technology disclosed in this specification can be realized in various forms, for example, an electrochemical reaction cell stack (fuel cell stack or electrolysis cell stack) having multiple electrochemical reaction cells or electrochemical reaction units, the above-mentioned composite, a manufacturing method thereof, etc.

FIG. 1 is a perspective view showing an external configuration of a fuel cell stack 100 according to an embodiment of the present invention; FIG. 2 is an explanatory diagram showing the XZ cross-sectional configuration of the fuel cell stack 100 taken along the line II-II in FIG. FIG. 2 is an explanatory diagram showing an XZ cross-sectional configuration of the fuel cell stack 100 taken along the line III-III in FIG. 1. FIG. 4 is an explanatory diagram showing the YZ cross-sectional configuration of the fuel cell stack 100 at the position IV-IV in FIG. FIG. 3 is an explanatory diagram showing the XZ cross-sectional configuration of two adjacent power generating units 102 at the same position as the cross-section shown in FIG. 2 . FIG. 4 is an explanatory diagram showing the XZ cross-sectional configuration of two adjacent power generating units 102 at the same position as the cross-section shown in FIG. 3 . FIG. 5 is an explanatory diagram showing the YZ cross-sectional configuration of two adjacent power generating units 102 at the same position as the cross-section shown in FIG. FIG. 8 is an explanatory diagram showing the XY cross-sectional configuration of the power generating unit 102 at the position VIII-VIII in FIG. 5. FIG. 6 is an explanatory diagram showing the XY cross-sectional configuration of the power generating unit 102 at the position IX-IX in FIG. 5. FIG. 1 is an enlarged explanatory diagram showing the joint structure between the lower end plate 106 and the lower terminal plate 420. FIG. 11 is an explanatory diagram showing the XY plane configuration of the gas passage member 27 and the like at the position XI-XI of FIG.

A. Embodiments:
A-1. Configuration:
(Configuration of fuel cell stack 100)
FIG. 1 is a perspective view showing the external configuration of a fuel cell stack 100 in this embodiment, FIG. 2 is an explanatory diagram showing the XZ cross-sectional configuration of the fuel cell stack 100 at the position II-II in FIG. 1, FIG. 3 is an explanatory diagram showing the XZ cross-sectional configuration of the fuel cell stack 100 at the position III-III in FIG. 1, and FIG. 4 is an explanatory diagram showing the YZ cross-sectional configuration of the fuel cell stack 100 at the position IV-IV in FIG. 1. Each figure shows mutually orthogonal XYZ axes for specifying a direction. In this specification, for convenience, the positive direction of the Z axis is referred to as the upward direction, and the negative direction of the Z axis is referred to as the downward direction, but the fuel cell stack 100 may actually be installed in a direction different from such an orientation. The same applies to FIG. 5 and subsequent figures. The fuel cell stack 100 is an example of a composite in the scope of the claims, and the up-down direction (Z axis direction) is an example of a first direction in the scope of the claims.

The fuel cell stack 100 includes a plurality of (seven in this embodiment) fuel cell power generation units (hereinafter simply referred to as "power generation units") 102, an end separator 210, an upper end plate 220, a lower end plate 189, a pair of terminal plates 410, 420, an insulating section 200, and a pair of end plates 104, 106. The seven power generation units 102 are arranged in a predetermined arrangement direction (up and down in this embodiment). One of the pair of terminal plates 410, 420 (hereinafter referred to as the "upper terminal plate 410") is arranged on the upper side of an assembly (hereinafter referred to as the "power generation block 103") consisting of the seven power generation units 102, and the other of the pair of terminal plates 410, 420 (hereinafter referred to as the "lower terminal plate 420") is arranged on the lower side of the power generation block 103. The end separator 210 is disposed above the upper terminal plate 410, and the lower end plate 189 is disposed below the lower terminal plate 420. The insulating section 200 is disposed above the end separator 210. One of the pair of end plates 104, 106 (hereinafter referred to as the "upper end plate 104") is disposed above the insulating section 200, and the other of the pair of end plates 104, 106 (hereinafter referred to as the "lower end plate 106") is disposed below the lower end plate 189. The pair of end plates 104, 106 are disposed so as to sandwich the power generation block 103, the end separator 210, the lower end plate 189, the pair of terminal plates 410, 420, and the insulating section 200 from above and below. The power generation unit 102 is an example of an electrochemical reaction unit in the claims, and the power generation block 103 is an example of an electrochemical reaction block in the claims.

1 and 4, holes are formed in the vicinity of the four corners of the outer periphery around the Z-axis direction of each layer constituting the fuel cell stack 100 (the power generation block 103, the terminal separator 210, the lower end plate 189, the pair of terminal plates 410, 420, and the insulating part 200) that penetrate each layer in the vertical direction. Holes (screw holes) are formed in the vicinity of the four corners of the outer periphery around the Z-axis direction of the upper end plate 104, and holes (screw holes) are formed in the vicinity of the four corners of the outer periphery around the Z-axis direction of the lower end plate 106. Corresponding holes formed in these layers communicate with each other in the vertical direction to form bolt holes 109 extending in the vertical direction. In the following description, the holes formed in each layer of the fuel cell stack 100 to form the bolt holes 109 may also be referred to as bolt holes 109.

A bolt 22 is inserted into each bolt hole 109. The upper end of each bolt 22 is screwed into a screw hole of a nut 24 through a hole in the upper end plate 104, and the lower end of each bolt 22 is screwed into a screw hole of a nut 24 through a hole in the lower end plate 106. The bolts 22 and nuts 24 configured in this way fasten each layer of the fuel cell stack 100 together.

As shown in Figures 1 to 3, four holes are formed in the peripheral portion around the Z axis direction of each layer (each power generating unit 102, lower terminal plate 420, lower end plate 189, lower end plate 106) constituting the fuel cell stack 100, penetrating each layer in the vertical direction, and corresponding holes formed in each layer communicate with each other in the vertical direction to form a communication hole 108 extending in the vertical direction from the uppermost power generating unit 102 to the lower end plate 106. In the following description, the holes formed in each layer of the fuel cell stack 100 to form the communication hole 108 may also be referred to as the communication hole 108. Note that, hereinafter, the hole formed in the lower end plate 106 among the communication holes 108 is specifically referred to as the end through hole 107.

1 and 2, one communication hole 108 located near one side (the side on the positive X-axis side of the two sides parallel to the Y-axis) constituting the outer periphery around the Z-axis of the fuel cell stack 100 functions as an oxidant gas supply manifold 161, which is a gas flow path through which oxidant gas OG is introduced from outside the fuel cell stack 100 and the oxidant gas OG is supplied to an air chamber 166 of each power generation unit 102, which will be described later, and one communication hole 108 located near the opposite side (the side on the negative X-axis side of the two sides parallel to the Y-axis) functions as an oxidant gas exhaust manifold 162, which is a gas flow path through which oxidant off-gas OOG, which is a gas exhausted from the air chamber 166 of each power generation unit 102, is exhausted to the outside of the fuel cell stack 100. The oxidant gas supply manifold 161 and the oxidant gas exhaust manifold 162 are gas flow paths that exchange gas with the air electrode 114 (described later) of each power generation unit 102. The oxidant gas OG may be, for example, air.

1 and 3, among the sides constituting the outer periphery around the Z-axis direction of the fuel cell stack 100, another communication hole 108 located near the side closest to the communication hole 108 functioning as the oxidant gas exhaust manifold 162 described above functions as a fuel gas supply manifold 171, which is a gas flow path through which fuel gas FG is introduced from outside the fuel cell stack 100 and the fuel gas FG is supplied to the fuel chamber 176 described later of each power generation unit 102, and another communication hole 108 located near the side closest to the communication hole 108 functioning as the oxidant gas supply manifold 161 described above functions as a fuel gas exhaust manifold 172, which is a gas flow path through which fuel off-gas FOG, which is gas exhausted from the fuel chamber 176 of each power generation unit 102, is exhausted to the outside of the fuel cell stack 100. The fuel gas supply manifold 171 and the fuel gas exhaust manifold 172 are gas flow paths that exchange gas with the fuel electrode 116 (described later) of each power generation unit 102. The fuel gas FG is, for example, hydrogen-rich gas obtained by reforming city gas. In the following, the air chamber 166 and the fuel chamber 176 are collectively referred to as the "gas chamber."

1 to 3, the fuel cell stack 100 is provided with four gas passage members 27. Each gas passage member 27 is formed of a conductive material (metal material) such as ferritic stainless steel containing aluminum, and has a hollow cylindrical main body 28 and a flange 29. The main body 28 is formed with a gas through hole 26 that penetrates in the vertical direction. One end (upper end) of the main body 28 is connected to an end through hole 107 formed in the lower end plate 106. Specifically, the upper end of the main body 28 is inserted into the end through hole 107 and joined by, for example, welding. The outer diameter and inner diameter of the upper end of the main body 28 are smaller than the outer diameter and inner diameter of the other end (lower end) of the main body 28. The plate thickness (difference between the outer diameter and the inner diameter) of the main body 28 can be, for example, 0.6 mm or more and 1.0 mm or less. The flange portion 29 is provided so as to protrude from the lower end side of the main body portion 28 in a planar direction (direction parallel to the XY plane) perpendicular to the vertical direction (Z-axis direction). The shape of the flange portion 29 when viewed in the vertical direction is approximately rectangular, and bolt holes 29A (see FIG. 1) are formed in each of the four corners. A bolt (not shown) for connecting the fuel cell stack 100 to an external device is inserted into each bolt hole 29A.

2, the gas through hole 26 of the gas passage member 27 arranged at the position of the oxidant gas supply manifold 161 is connected to the oxidant gas supply manifold 161, and the gas through hole 26 of the gas passage member 27 arranged at the position of the oxidant gas exhaust manifold 162 is connected to the oxidant gas exhaust manifold 162. Also, as shown in FIG. 3, the gas through hole 26 of the gas passage member 27 arranged at the position of the fuel gas supply manifold 171 is connected to the fuel gas supply manifold 171, and the gas through hole 26 of the gas passage member 27 arranged at the position of the fuel gas exhaust manifold 172 is connected to the fuel gas exhaust manifold 172.

(Configuration of end plates 104, 106)
The pair of end plates 104, 106 are flat members with an approximately rectangular outer shape as viewed in the Z-axis direction, and are made of a conductive material (metal material) such as ferritic stainless steel that forms an alumina oxide film on the surface. Holes 32, 34 are formed near the center of the pair of end plates 104, 106, respectively, penetrating in the Z-axis direction. As viewed in the Z-axis direction, the inner circumferential lines of the holes 32, 34 formed in each of the pair of end plates 104, 106 include at least a part of each unit cell 110 described later. The compressive force in the Z-axis direction generated by fastening with each bolt 22 and nut 24 mainly acts on the periphery of each power generating unit 102 (the part on the outer periphery side of each unit cell 110 described later). Each of the end plates 104, 106 is formed by pressing (bending) a single plate-shaped member. The plate thickness of the end plates 104 , 106 may be, for example, 1 mm or more and 3 mm or less, and may be the same as or thinner than the plate thickness of the main body 28 of the gas passage member 27 .

2 to 4, the upper end plate 104 includes a planar portion 310 and a convex portion 320. The planar portion 310 is a flat portion along a surface direction perpendicular to the Z-axis direction (parallel to the XY plane). Specifically, the shape of the planar portion 310 as viewed in the Z-axis direction is a rectangular frame shape as a whole. The holes constituting the bolt holes 109 described above are formed in the peripheral portion around the Z-axis direction in the planar portion 310. The convex portion 320 is a rib protruding upward from the planar portion 310. The convex portion 320 has an outer convex portion 322 and an inner convex portion 324. The outer convex portion 322 protrudes upward from the outer periphery of the planar portion 310. The outer convex portion 322 is formed around the entire circumference of the outer periphery of the planar portion 310. The inner convex portion 324 protrudes upward from the inner periphery of the planar portion 310. The inner convex portion 324 is formed around the entire inner circumference of the flat portion 310.

The lower end plate 106 includes a planar portion 510 and a convex portion 520. The planar portion 510 is a flat portion along a surface direction perpendicular to the Z-axis direction (parallel to the XY plane). Specifically, the shape of the planar portion 510 as viewed in the Z-axis direction is a rectangular frame shape as a whole. The holes constituting the bolt holes 109 described above are formed in the peripheral portion around the Z-axis direction in the planar portion 510. The convex portion 520 is a rib protruding downward from the planar portion 510. The convex portion 520 has an outer convex portion 522 and an inner convex portion 524. The outer convex portion 522 protrudes downward from the outer periphery of the planar portion 510. The outer convex portion 522 is formed around the entire circumference of the outer periphery of the planar portion 510. The inner convex portion 524 protrudes downward from the inner periphery of the planar portion 510. The inner convex portion 524 is formed around the entire inner circumference of the flat portion 510.

2 and 3, a reinforcing member 600 is fixed to the lower end plate 106. The reinforcing member 600 has a flat portion 610 and a tube portion 620. The flat portion 610 is a flat portion parallel to the planar portion 510 of the lower end plate 106. The shape of the flat portion 610 when viewed in the vertical direction is approximately rectangular. The flat portion 610 is disposed at a position spaced downward from the planar portion 510 of the lower end plate 106. One side of the flat portion 610 in the longitudinal direction contacts the inner wall surface of the outer convex portion 522 and is joined thereto by, for example, welding, and the other side of the flat portion 610 in the longitudinal direction contacts the inner wall surface of the inner convex portion 524 and is joined thereto by, for example, welding. The flat portion 610 has a through hole 612 into which the main body 28 of the gas passage member 27 can be inserted. The tubular portion 620 is a cylindrical portion having a through hole 622 that communicates with the through hole 612 of the flat portion 610. The tubular portion 620 is formed so as to protrude downward from the periphery of the through hole 612 in the flat portion 610. The inner wall surfaces constituting the through hole 612 of the flat portion 610 and the through hole 622 of the tubular portion 620 contact the outer peripheral surface of the main body 28 of the gas passage member 27 and are joined by, for example, welding. The flat portion 610 and the tubular portion 620 are integrally formed. The reinforcing member 600 is preferably formed of a heat-resistant material, or the same material as the lower end plate 106, the gas passage member 27, etc., or a material having the same thermal expansion coefficient, and is formed of, for example, a metal (ferritic stainless steel, etc.).

(Configuration of Terminal Plates 410, 420)
The pair of terminal plates 410, 420 are flat members with an approximately rectangular outer shape as viewed in the Z-axis direction, and are made of a conductive material such as ferritic stainless steel that forms an alumina oxide film on the surface. A hole 412 is formed near the center of the upper terminal plate 410, penetrating in the Z-axis direction. As viewed in the Z-axis direction, the inner periphery of the hole 412 formed in the upper terminal plate 410 includes each of the unit cells 110 described below. As viewed in the Z-axis direction, one end of each of the pair of terminal plates 410, 420 on one side (the X-axis positive direction side) protrudes laterally from the power generation block 103. In this embodiment, the protruding portion of the upper terminal plate 410 functions as a positive output terminal of the fuel cell stack 100, and the protruding portion of the lower terminal plate 420 functions as a negative output terminal of the fuel cell stack 100.

(Configuration of the upper end plate 220)
The upper end plate 220 is a flat member having a substantially rectangular outer shape when viewed in the Z-axis direction, and is made of a conductive material such as stainless steel. The upper end plate 220 is disposed above the power generation block 103, and is electrically connected to an interconnector 190 (described below) located at the upper end of the power generation block 103. In this embodiment, the upper end plate 220 and the interconnector 190 are electrically connected via a connection member having the same structure as a fuel electrode side current collecting member 144 described below.

(Configuration of Terminal Separator 210)
The terminal separator 210 is a frame-like member having a generally rectangular through hole 211 that penetrates in the vertical direction near the center, and is made of, for example, metal. A portion of the terminal separator 210 surrounding the through hole 211 (hereinafter referred to as the "through hole surrounding portion") is joined to the upper surface of the periphery of the upper end plate 220, for example by welding. The terminal separator 210 separates the space between the upper end plate 220 and the power generation block 103 from the external space of the fuel cell stack 100.

The terminal separator 210 includes an inner portion 216 including the through-hole periphery of the terminal separator 210, an outer portion 217 located on the outer periphery side of the inner portion 216, and a connecting portion 218 connecting the inner portion 216 and the outer portion 217. In this embodiment, the inner portion 216 and the outer portion 217 are substantially flat plates extending in a direction substantially perpendicular to the Z-axis direction. The connecting portion 218 is curved so as to protrude downward from both the inner portion 216 and the outer portion 217. The lower portion (the power generation block 103 side) of the connecting portion 218 is a convex portion, and the upper portion (the upper end plate 104 side) of the connecting portion 218 is a concave portion. Therefore, the connecting portion 218 includes a portion whose position in the Z-axis direction is different from that of the inner portion 216 and the outer portion 217.

(Configuration of the lower end plate 189)
The lower end plate 189 is a flat member having a substantially rectangular outer shape as viewed in the Z-axis direction, and is made of, for example, an insulating material. The peripheral portion of the lower end plate 189 is sandwiched between the lower terminal plate 420 and the lower end plate 106, thereby ensuring insulation between the lower terminal plate 420 and the lower end plate 106.

(Configuration of insulating portion 200)
The insulating part 200 is a frame-shaped member having a substantially rectangular through hole formed in the vertical direction near the center, and is made of, for example, an insulating material. The insulating part 200 is sandwiched between the upper end plate 104 and the terminal separator 210, thereby ensuring sealing of the manifolds 161, 162, 171, 172 and insulation between the upper end plate 104 and the terminal separator 210.

(Configuration of power generation unit 102)
Fig. 5 is an explanatory diagram showing the XZ cross-sectional configuration of two adjacent power generating units 102 at the same position as the cross-section shown in Fig. 2, Fig. 6 is an explanatory diagram showing the XZ cross-sectional configuration of two adjacent power generating units 102 at the same position as the cross-section shown in Fig. 3, and Fig. 7 is an explanatory diagram showing the YZ cross-sectional configuration of two adjacent power generating units 102 at the same position as the cross-section shown in Fig. 4. Fig. 8 is an explanatory diagram showing the XY cross-sectional configuration of the power generating unit 102 at the position VIII-VIII in Fig. 5, and Fig. 9 is an explanatory diagram showing the XY cross-sectional configuration of the power generating unit 102 at the position IX-IX in Fig. 5.

As shown in Figures 5 to 7, the power generation unit 102 includes a single fuel cell (hereinafter referred to as a "single cell") 110, a single cell separator 120, an air electrode side frame 130, a fuel electrode side frame 140, a fuel electrode side current collecting member 144, a pair of interconnectors 190 constituting the top and bottom layers of the power generation unit 102, and a pair of IC separators 180. The single cell separator 120, the air electrode side frame 130, the fuel electrode side frame 140, and the IC separator 180 have holes constituting the communication holes 108 that function as the manifolds 161, 162, 171, and 172, and holes constituting the bolt holes 109 formed in the peripheral portions around the Z axis direction.

The single cell 110 includes an electrolyte layer 112, an air electrode 114 arranged on one side (upper side) of the electrolyte layer 112 in the Z-axis direction, a fuel electrode 116 arranged on the other side (lower side) of the electrolyte layer 112 in the Z-axis direction, and a reaction prevention layer 118 arranged between the electrolyte layer 112 and the air electrode 114. The single cell 110 of this embodiment is a fuel electrode-supported single cell in which the fuel electrode 116 supports the other layers (electrolyte layer 112, air electrode 114, reaction prevention layer 118) that constitute the single cell 110. The single cell 110 is an example of an electrochemical reaction single cell in the claims.

The electrolyte layer 112 is a substantially rectangular flat-plate member as viewed in the Z-axis direction, and is configured to include a solid oxide (e.g., YSZ (yttria-stabilized zirconia)). That is, the unit cell 110 of this embodiment is a solid oxide fuel cell (SOFC) that uses a solid oxide as an electrolyte. The air electrode 114 is a substantially rectangular flat-plate member smaller than the electrolyte layer 112 as viewed in the Z-axis direction, and is configured to include, for example, a perovskite-type oxide (e.g., LSCF (lanthanum strontium cobalt iron oxide)). The fuel electrode 116 is a substantially rectangular flat-plate member having substantially the same size as the electrolyte layer 112 as viewed in the Z-axis direction, and is formed of, for example, Ni (nickel), a cermet made of Ni and ceramic particles, a Ni-based alloy, or the like. The reaction prevention layer 118 is a substantially rectangular flat-plate member having substantially the same size as the air electrode 114 as viewed in the Z-axis direction, and is configured to include, for example, GDC (gadolinium-doped ceria). The reaction prevention layer 118 has a function of suppressing the generation of a highly resistive substance (e.g., SrZrO ₃ ) caused by the reaction of an element (e.g., Sr) diffused from the air electrode 114 with an element (e.g., Zr) contained in the electrolyte layer 112. The air electrode 114 and the fuel electrode 116 are examples of a specific electrode in the claims.

The single cell separator 120 is a frame-shaped member with a substantially rectangular through hole 121 formed in the center that penetrates vertically, and is made of, for example, metal. The portion of the single cell separator 120 surrounding the through hole 121 (hereinafter referred to as the "through hole surrounding portion") faces the upper surface of the peripheral portion of the single cell 110 (electrolyte layer 112). The single cell separator 120 is joined to the single cell 110 (electrolyte layer 112) by a joint 124 formed of a brazing material (e.g., Ag brazing) arranged in the opposing portion. The single cell separator 120 divides an air chamber 166 facing the air electrode 114 and a fuel chamber 176 facing the fuel electrode 116, and gas leakage (cross leakage) from one electrode side to the other electrode side at the peripheral portion of the single cell 110 is suppressed.

The single cell separator 120 includes an inner portion 126 including the through-hole periphery of the single cell separator 120, an outer portion 127 located on the outer periphery side of the inner portion 126, and a connecting portion 128 connecting the inner portion 126 and the outer portion 127. In this embodiment, the inner portion 126 and the outer portion 127 are substantially flat plates extending in a direction substantially perpendicular to the Z-axis direction. The connecting portion 128 is curved so as to protrude downward from both the inner portion 126 and the outer portion 127. The lower portion (fuel chamber 176 side) of the connecting portion 128 is a convex portion, and the upper portion (air chamber 166 side) of the connecting portion 128 is a concave portion. Therefore, the connecting portion 128 includes a portion whose position in the Z-axis direction is different from that of the inner portion 126 and the outer portion 127.

A glass seal portion 125 containing glass is disposed near the through hole 121 in the single cell separator 120. The glass seal portion 125 is located on the air chamber 166 side of the joint portion 124, and is formed so as to contact both the surface around the through hole of the single cell separator 120 and the surface of the single cell 110 (electrolyte layer 112 in this embodiment). The glass seal portion 125 effectively prevents gas leakage (cross leakage) from one electrode side to the other electrode side at the periphery of the single cell 110.

The interconnector 190 is a conductive member having a flat plate portion 150 having a substantially rectangular flat plate shape and a plurality of substantially columnar air electrode side current collecting portions 134 protruding from the flat plate portion 150 toward the air electrode 114 side, and is formed of a metal (e.g., ferritic stainless steel). In this embodiment, a conductive coating layer 194 composed of, for example, a spinel-type oxide is formed on the surface of the interconnector 190 (the surface facing the air chamber 166). Hereinafter, the interconnector 190 covered with the coating layer 194 will be simply referred to as the interconnector 190. The interconnector 190 (each of the air electrode side current collecting portions 134) is joined to the air electrode 114 of the single cell 110 via a conductive bonding material 196 composed of, for example, a spinel-type oxide, and is thus electrically connected to the air electrode 114 of the single cell 110. The interconnector 190 ensures electrical conduction between the power generation units 102 and suppresses the mixing of reaction gases between the power generation units 102. In this embodiment, when two power generating units 102 are arranged adjacent to each other, one interconnector 190 is shared by the two adjacent power generating units 102. That is, the upper interconnector 190 of one power generating unit 102 is made of the same material as the lower interconnector 190 of the other power generating unit 102 adjacent to the upper side of the power generating unit 102. In addition, since the fuel cell stack 100 includes a lower terminal plate 420 and a lower end plate 189, the power generating unit 102 located at the bottom of the fuel cell stack 100 does not include a lower interconnector 190 (see Figures 2 to 4).

The IC separator 180 is a frame-like member with a substantially rectangular through hole 181 formed in the center that penetrates vertically, and is made of, for example, metal. The portion of the IC separator 180 that surrounds the through hole 181 (hereinafter referred to as the "through hole surrounding portion") is joined, for example by welding, to the upper surface of the peripheral portion of the flat portion 150 of the interconnector 190. Of a pair of IC separators 180 included in a certain generating unit 102, the upper IC separator 180 partitions the air chamber 166 of the generating unit 102 and the fuel chamber 176 of the other generating unit 102 adjacent to the generating unit 102 on the upper side. In addition, of the pair of IC separators 180 included in a certain generating unit 102, the lower IC separator 180 separates the fuel chamber 176 of the generating unit 102 from the air chamber 166 of the other generating unit 102 adjacent to the generating unit 102 on the lower side. In this way, the IC separator 180 suppresses gas leakage between the generating units 102 at the periphery of the generating units 102. The IC separator 180 joined to the upper interconnector 190 of the generating unit 102 located at the topmost position in the fuel cell stack 100 is electrically connected to the upper terminal plate 410.

The IC separator 180 includes an inner portion 186 including the through-hole periphery of the IC separator 180, an outer portion 187 located on the outer periphery side of the inner portion 186, and a connecting portion 188 connecting the inner portion 186 and the outer portion 187. In this embodiment, the inner portion 186 and the outer portion 187 are substantially flat plates extending in a direction substantially perpendicular to the Z-axis direction. The connecting portion 188 is curved so as to protrude downward from both the inner portion 186 and the outer portion 187. The lower portion (air chamber 166 side) of the connecting portion 188 is a convex portion, and the upper portion (fuel chamber 176 side) of the connecting portion 188 is a concave portion. Therefore, the connecting portion 188 includes a portion whose position in the Z-axis direction is different from that of the inner portion 186 and the outer portion 187.

8, the air electrode side frame 130 is a frame-shaped member with a substantially rectangular hole 131 formed near the center penetrating in the Z-axis direction, and is formed of an insulator such as mica. The hole 131 of the air electrode side frame 130 constitutes an air chamber 166 facing the air electrode 114. The air electrode side frame 130 is in contact with the upper surface of the peripheral portion of the single cell separator 120 and the lower surface of the peripheral portion of the upper IC separator 180, and functions as a sealing member that ensures gas sealing between the two (i.e., gas sealing of the air chamber 166). In addition, the air electrode side frame 130 electrically insulates a pair of IC separators 180 included in the power generation unit 102 (i.e., a pair of interconnectors 190). In addition, the air electrode side frame 130 is formed with an oxidant gas supply communication hole 132 that connects the oxidant gas supply manifold 161 to the air chamber 166, and an oxidant gas discharge communication hole 133 that connects the air chamber 166 to the oxidant gas discharge manifold 162.

9, the fuel electrode side frame 140 is a frame-shaped member with a substantially rectangular hole 141 formed near the center that penetrates in the Z-axis direction, and is made of, for example, metal. The hole 141 of the fuel electrode side frame 140 constitutes a fuel chamber 176 that faces the fuel electrode 116. The fuel electrode side frame 140 is in contact with the lower surface of the peripheral portion of the single cell separator 120 and the upper surface of the peripheral portion of the lower IC separator 180. In addition, the fuel electrode side frame 140 is formed with a fuel gas supply communication hole 142 that connects the fuel gas supply manifold 171 and the fuel chamber 176, and a fuel gas discharge communication hole 143 that connects the fuel chamber 176 and the fuel gas discharge manifold 172.

5 to 7, the fuel electrode side current collecting member 144 is disposed in the fuel chamber 176. The fuel electrode side current collecting member 144 includes an interconnector facing portion 146, an electrode facing portion 145, and a connecting portion 147 connecting the electrode facing portion 145 and the interconnector facing portion 146, and is formed of, for example, nickel, a nickel alloy, stainless steel, or the like. The electrode facing portion 145 is in contact with the lower surface of the fuel electrode 116, and the interconnector facing portion 146 is in contact with the upper surface of the interconnector 190 (the flat portion 150 of the interconnector 190). However, as described above, since the power generating unit 102 located at the bottom of the fuel cell stack 100 does not include a lower interconnector 190, the interconnector facing portion 146 of the fuel electrode side current collecting member 144 in the power generating unit 102 is in contact with the lower terminal plate 420. The fuel electrode side current collecting member 144 has such a configuration, and thus electrically connects the fuel electrode 116 and the interconnector 190 (or the lower end plate 189). A spacer 149 made of, for example, mica is disposed between the electrode facing portion 145 and the interconnector facing portion 146 of the fuel electrode side current collecting member 144. Therefore, the fuel electrode side current collecting member 144 follows the deformation of the power generating unit 102 due to temperature cycles and reactant gas pressure fluctuations, and the electrical connection between the fuel electrode 116 and the interconnector 190 (or the lower terminal plate 420) via the fuel electrode side current collecting member 144 is well maintained. The fuel electrode side current collecting member 144 is fabricated, for example, by making a plurality of rectangular cuts in a flat plate-shaped material (for example, nickel foil having a thickness of 10 to 200 μm), placing a sheet-shaped fuel electrode side current collecting member 144 having a plurality of holes formed therein on the material, and bending and processing the plurality of rectangular portions so as to sandwich the spacer 149. Each bent rectangular portion becomes the electrode facing portion 145, the flat portion with holes other than the bent portions becomes the interconnector facing portion 146, and the portion connecting the electrode facing portion 145 and the interconnector facing portion 146 becomes the connection portion 147.

A-2. Operation of the fuel cell stack 100:
2 and 5, when the oxidant gas OG is supplied through a gas pipe (not shown) connected to the main body 28 of the gas passage member 27 provided at the position of the oxidant gas supply manifold 161, the oxidant gas OG is supplied to the oxidant gas supply manifold 161 through the gas through hole 26 of the gas passage member 27, and is supplied from the oxidant gas supply manifold 161 to the air chamber 166 through the oxidant gas supply communication hole 132 of each power generation unit 102. Also, as shown in Figs. 3 and 6, when the fuel gas FG is supplied through a gas pipe (not shown) connected to the main body 28 of the gas passage member 27 provided at the position of the fuel gas supply manifold 171, the fuel gas FG is supplied to the fuel gas supply manifold 171 through the gas through hole 26 of the gas passage member 27, and is supplied to the fuel chamber 176 from the fuel gas supply manifold 171 through the fuel gas supply communication hole 142 of each power generation unit 102.

When the oxidant gas OG is supplied to the air chamber 166 of each power generating unit 102 and the fuel gas FG is supplied to the fuel chamber 176, power is generated in the single cell 110 by an electrochemical reaction of the oxidant gas OG and the fuel gas FG. This power generation reaction is an exothermic reaction. In each power generating unit 102, the air electrode 114 of the single cell 110 is electrically connected to the upper interconnector 190, and the fuel electrode 116 is electrically connected to the lower interconnector 190 (or the lower end plate 189) via the fuel electrode side current collecting member 144. That is, the multiple power generating units 102 included in the fuel cell stack 100 are electrically connected in series. In addition, the upper interconnector 190 and the IC separator 180 of the power generating unit 102 located at the top are electrically connected to the upper terminal plate 410, and the lower terminal plate 420 is electrically connected to the fuel electrode side current collecting member 144 of the power generating unit 102 located at the bottom. Therefore, the electrical energy generated in each power generation unit 102 is extracted from the terminal plates 410, 420 that function as the output terminals of the fuel cell stack 100. Since SOFCs generate electricity at relatively high temperatures (e.g., 600°C to 1000°C), the fuel cell stack 100 may be heated by a heater (not shown) after startup until the high temperature can be maintained by the heat generated by power generation.

2 and 5, the oxidant off-gas OOG discharged from the air chamber 166 of each power generation unit 102 to the oxidant gas discharge manifold 162 through the oxidant gas discharge communication hole 133 passes through the gas through hole 26 of the main body 28 of the gas passage member 27 provided at the position of the oxidant gas discharge manifold 162, and is discharged to the outside of the fuel cell stack 100 through a gas piping (not shown) connected to the main body 28. Also, as shown in FIG. 3 and FIG. 6, the fuel off-gas FOG discharged from the fuel chamber 176 of each power generation unit 102 to the fuel gas discharge manifold 172 through the fuel gas discharge communication hole 143 passes through the gas through hole 26 of the main body 28 of the gas passage member 27 provided at the position of the fuel gas discharge manifold 172, and is discharged to the outside of the fuel cell stack 100 through a gas piping (not shown) connected to the main body 28.

The fuel cell stack 100 of this embodiment is a counterflow type SOFC in which the main flow direction of the oxidant gas OG in the air chamber 166 (direction from the positive direction of the X-axis to the negative direction of the X-axis) and the main flow direction of the fuel gas FG in the fuel chamber 176 (direction from the negative direction of the X-axis to the positive direction of the X-axis) are substantially opposite (opposing) directions in each power generation unit 102.

A-3. Joint structure between the lower end plate 106 and the lower terminal plate 420:
Next, the joining structure between the lower end plate 106 and the lower terminal plate 420 in the fuel cell stack 100 of this embodiment will be described. Fig. 10 is an explanatory diagram showing an enlarged view of the joining structure between the lower end plate 106 and the lower terminal plate 420, and Fig. 11 is an explanatory diagram showing the XY plane configuration of the gas passage member 27 and the like at the position XI-XI in Fig. 10. Fig. 11 illustrates the gas passage member 27 that communicates with the oxidant gas supply manifold 161. In Fig. 11, the gas passage member 27 and the lower end plate 106 are indicated by solid lines, and the glass seal member 197, the communication hole 108, and the like located behind the lower end plate 106 are indicated by dotted lines.

As shown in Figs. 2 to 4, 10 and 11, four erected portions 530 are formed on the lower end plate 106 of this embodiment. The erected portions 530 are cylindrical and protrude downward (Z-axis negative direction side) from the flat portion 510 of the lower end plate 106, and surround the end through hole 107 of the lower end plate 106 when viewed in the up-down direction. The erected portions 530 are integrally formed on the flat portion 510. In this embodiment, the inner wall surface of the lower end plate 106 that defines the end through hole 107 and the inner peripheral wall of the erected portions 530 are connected flush with each other without any steps. The lower end plate 106 is an example of a first member in the claims, and the end through hole 107 is an example of a first through hole in the claims.

The gas passage member 27 is connected to the erected portion 530 of the lower end plate 106, and the gas flow path of the gas passage member 27 communicates with the end through-hole 107 of the lower end plate 106. Specifically, the tip portion 28a of the gas passage member 27 is inserted into the inner periphery of the erected portion 530, and the tip portion 28a of the gas passage member 27 and the erected portion 530 are joined, for example, by welding. The gas passage member 27 is an example of a cylindrical member in the claims.

A glass seal member 197 made of glass is disposed between the lower end plate 106 and the lower terminal plate 420. The glass seal member 197 is disposed in a frame shape around the communication hole 108 (hereinafter referred to as "block communication hole 108B") formed in the power generation block 103 when viewed in the vertical direction. The glass seal member 197 is a member that joins adjacent members in the vertical direction (the lower end plate 106 and the lower terminal plate 420). The thickness of the glass seal member 197 can be, for example, 1.0 mm or more and 1.5 mm or less. The glass seal member 197 is an example of a joining member in the scope of the claims, and the lower terminal plate 420 is an example of a second member in the scope of the claims.

11, the glass seal member 197 is disposed outside the connection periphery 520b of the lower end plate 106 in the vertical view. The connection periphery 520b is a portion of the lower end plate 106 (flat portion 510) that surrounds the outline of the connection portion with the erected portion 530 of the gas passage member 27 (the outline of the tip portion 28a of the body portion 28 of the gas passage member 27 in FIG. 11) in the vertical view. Specifically, the glass seal member 197 is a frame-shaped member in which an insertion hole 197a is formed, and the outline of the insertion hole 197a surrounds the periphery of the end through hole 107 of the lower end plate 106 in the vertical view. The difference between the inner diameter and the outer diameter of the glass seal member 197 can be, for example, 2 mm or more and 4 mm or less. When viewed from the top and bottom, the contour of the insertion hole 197a is located outside the connection periphery 520b of the lower end plate 106 along its entire circumference. The insertion hole 197a is an example of a second through hole in the claims.

11 indicates the center of the space surrounded by the outline of the connection portion (tip portion 28a) of the gas passage member 27 (hereinafter referred to as "center O of the connection portion"). When viewed in the up-down direction, at least on two imaginary straight lines L1 and L2 extending in different directions from the center O of the connection portion, the distances between the connection portion of the gas passage member 27 and the glass seal member 197 are different from each other. Specifically, as shown in FIG. 11, the first distance D1 between the connection portion and the glass seal member 197 on the first imaginary straight line L1 (the imaginary straight line extending in the negative Y-axis direction from the center O of the connection portion) and the second distance D2 between the connection portion and the glass seal member 197 on the second imaginary straight line L2 (the imaginary straight line extending in the positive Y-axis direction from the center O of the connection portion) are different from each other. In other words, in this embodiment, the two separation distances D1, D2 between the connection portion and the glass seal member 197 on one imaginary straight line L1 (L2) passing through the center O are different from each other.

More specifically, of the block communication holes 108B of the power generation block 103, the block communication holes 108B constituting the oxidant gas supply manifold 161 are elongated holes extending in a predetermined direction (Y-axis direction). When viewed in the vertical direction, the end through-hole 107 (standing portion 530) of the lower end plate 106 is disposed at a position offset in the predetermined direction (positive Y-axis direction side) within the contour line of the block communication hole 108B. The insertion hole 197a of the glass seal member 197 is a elongated hole one size larger than the block communication hole 108B, and the contour line of the insertion hole 197a surrounds the periphery of the block communication hole 108B. With this configuration, the first separation distance D1 is longer than the second separation distance D2.

In this embodiment, the block communication holes 108B of the power generation block 103 that constitute the oxidant gas exhaust manifold 162 are also elongated holes extending in a predetermined direction (Y-axis direction) (see FIG. 8, etc.). For this reason, the glass seal member 197 arranged to communicate with the oxidant gas exhaust manifold 162 also has two different distances from the connection part on a virtual straight line passing through the center of the connection part of the gas passage member 27. On the other hand, the block communication holes 108B that respectively constitute the fuel gas supply manifold 171 and the fuel gas exhaust manifold 172 are circular holes (see FIG. 8, etc.). In this embodiment, the center of the glass seal member 197 arranged to communicate with these manifolds 171, 172 is arranged so as to approximately coincide with the center of the connection part of the gas passage member 27, and the distance between the connection part of the gas passage member 27 and the glass seal member 197 is approximately uniform over the entire circumference.

The rigidity of the overlapping portion 510a of the lower end plate 106 that overlaps with the glass seal member 197 in the vertical view is higher than the rigidity of the connection peripheral portion 520b. Specifically, as shown in FIG. 10, a reinforcing portion 523 is provided on the lower surface of the flat portion 510 of the lower end plate 106. The reinforcing portion 523 is made of, for example, metal and is joined to the lower surface of the flat portion 510. The reinforcing portion 523 is formed so as to surround the periphery of the connection peripheral portion 520b of the lower end plate 106 in the vertical view. The reinforcing portion 523 is preferably formed of a heat-resistant material, or the same material as the lower end plate 106, the gas passage member 27, etc., or a material having the same thermal expansion coefficient, and is formed of, for example, a metal (ferritic stainless steel, etc.).

A-4. Advantages of this embodiment:
As described above, the fuel cell stack 100 of this embodiment is disposed outside the connection peripheral portion 520b of the lower end plate 106 in the vertical view (see FIGS. 10 and 11). Therefore, even if the connection peripheral portion 520b of the lower end plate 106 is deformed due to the displacement of the gas passage member 27, the deformation is not easily transmitted to the glass seal member 197. As a result, according to this embodiment, it is possible to suppress damage to the joint portion of the glass seal member 197 caused by the displacement of the gas passage member 27. The displacement of the gas passage member 27 is, for example, the movement of the erected portion 530 in the axial direction (Z-axis direction) or the inclination of the base end side (lower end side) of the gas passage member 27 with respect to the axial direction. The displacement of the gas passage member 27 is caused by, for example, stress caused by a difference in thermal expansion between the gas passage member 27 and the lower end plate 106, etc., or an external force on the gas passage member 27.

In this embodiment, the glass seal member 197 is disposed between the lower end plate 106 and the adjacent lower terminal plate 420 (see FIG. 10). Even in this configuration in which the glass seal member 197 is disposed in a position close to the deformation location of the lower end plate 106, the application of the present invention can prevent damage to the joints of the glass seal member 197 due to the displacement of the gas passage member 27.

In this embodiment, the rigidity of the overlapping portion 510a of the lower end plate 106 that overlaps with the glass seal member 197 when viewed in the vertical direction is higher than the rigidity of the connection periphery 520b (see FIG. 10). Therefore, even if the connection periphery 520b of the lower end plate 106 is deformed, the overlapping portion 510a of the lower end plate 106 is less likely to deform. This prevents the deformation of the lower end plate 106 from being transmitted to the glass seal member 197, and effectively prevents damage to the joint of the glass seal member 197 due to the displacement of the gas passage member 27.

In this embodiment, the distances between the connection portion of the gas passage member 27 and the glass seal member 197 are different from each other on at least two imaginary straight lines L1 and L2 extending in different directions from the center O of the connection portion when viewed in the up-down direction (see FIG. 11). According to this embodiment, for example, when the gas passage member 27 is displaced in a direction that deforms the connection peripheral portion 520b on the side in which the separation distance is longer (first separation distance D1), damage to the joint portion by the glass seal member 197 can be effectively suppressed. In this embodiment, as shown in FIG. 11, the end through hole 107 of the lower end plate 106 is disposed at a position offset from the block communication hole 108B formed in the lower terminal plate 420 (power generation block 103). Therefore, the portion of the lower end plate 106 (flat portion 510) on the first separation distance D1 side is more easily deformed than the portion on the second separation distance D2 side. In contrast, in this embodiment, the first separation distance D1 is longer than the second separation distance D2, so that when the gas passage member 27 is displaced in a direction that deforms the connection periphery 520b on the first separation distance D1 side, damage to the joint by the glass seal member 197 can be effectively prevented.

B. Variations:
The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

The configuration of the fuel cell stack 100 and the power generation unit 102 in the above embodiment is merely an example and can be modified in various ways.

In the above embodiment, the inner wall surface of the lower end plate 106 that defines the communication hole 108 and the inner peripheral wall of the erected portion 530 are connected flush with each other without any steps, but this is not limited thereto, and for example, the inner peripheral wall of the erected portion 530 may be located outside the inner wall surface that defines the communication hole 108 when viewed in the vertical direction. In the above embodiment, a circular or elongated communication hole 108 formed in the lower end plate 106 is exemplified as the first through hole, but this is not limited thereto, and a rectangular or polygonal through hole may be used, for example.

In the above embodiment, the erected portion 530 of the lower end plate 106 may be inserted into the tip portion 28a of the gas passage member 27, or the lower end surface of the erected portion 530 may be butted against the upper end surface of the gas passage member 27 and joined. In the above embodiment, the gas passage member 27 in which a gas flow path is formed is illustrated as an example of a cylindrical member, but this is not limited to this, and a simple cylindrical member that does not form a gas flow path may be used as long as it is a member connected to the erected portion of the first member. In addition, the shape of the cylindrical member is not limited to a straight shape like the gas passage member 27, and may be a curved shape.

In the above embodiment, the glass seal member 197 made of glass is exemplified as the joining member, but any member having a joining function may be formed of a material other than glass (e.g., metal or resin). Also, in the above embodiment, the glass seal member 197 is formed so as to surround the periphery of the communication hole 108 formed in the lower end plate 106 when viewed in the vertical direction (see FIG. 11), and functions as a seal member that suppresses gas leakage, but this is not limited thereto, and for example, the glass seal member 197 may be formed only in a portion of the periphery of the communication hole 108 formed in the lower end plate 106.

In the above embodiment, the lower terminal plate 420 adjacent to the lower end plate 106 in the vertical direction is exemplified as the second member, but this is not limited thereto, and a member that is not adjacent to the lower end plate 106 in the vertical direction may be used. For example, in the above embodiment, one or more intermediate members may be disposed between the lower end plate 106 and the lower terminal plate 420. In this configuration, the joining member may be a member that joins the lower end plate 106 and the intermediate member, a member that joins the lower terminal plate 420 and the intermediate member, or a member that joins the intermediate members together.

In the above embodiment, a configuration in which a reinforcing portion 523 is provided on the lower end plate 106 is adopted as a means for making the rigidity of the overlapping portion 510a of the lower end plate 106 higher than the rigidity of the connection peripheral portion 520b. Other means may be adopted, such as making the thickness of the overlapping portion 510a of the lower end plate 106 thicker than the thickness of the connection peripheral portion 520b (the overlapping portion 510a and the connection peripheral portion 520b are formed from the same material) or forming a rib or the like on the overlapping portion 510a of the lower end plate 106.

In the above embodiment, as two imaginary straight lines extending in different directions, imaginary straight lines L1 and L2 extending in opposite directions from the center O of the connection portion are illustrated, but the present invention is not limited to this, and two imaginary straight lines extending in intersecting directions may be used. For example, in the configuration of FIG. 11, the end through hole 107 may be located at the center of the block communication hole 108B in the longitudinal direction (Y-axis direction) of the block communication hole 108B. In this configuration, the separation distance between the connection portion of the gas passage member 27 and the glass seal member 197 is different on two imaginary straight lines extending from the center O of the connection portion in mutually orthogonal directions (Y-axis direction, X-axis direction). With this configuration, it is possible to effectively prevent damage to the joint by the glass seal member 197 when the gas passage member 27 is displaced in the Y-axis direction.

In the above embodiment, the holes 32, 34 are formed in the pair of end plates 104, 106, but the holes 32, 34 do not have to be formed in at least one of the pair of end plates 104, 106. Also, in the above embodiment, the fuel cell stack 100 includes a pair of terminal plates 410, 420, but other members (e.g., the pair of end plates 104, 106) may also function as terminal plates, and the terminal plates 410, 420 as dedicated members may be omitted.

In the above embodiment, the single cell separator 120 has a curved connecting portion 128 that protrudes downward from both the inner portion 126 and the outer portion 127, but the shape of the connecting portion 128 may be other shapes. Also, the single cell separator 120 does not have to have the connecting portion 128. The same applies to the connecting portion 188 in the IC separator 180.

In the above embodiment, the glass seal portion 125 is disposed near the hole 121 in the single cell separator 120, but the glass seal portion 125 may be omitted.

In the above embodiment, the interconnector 190 includes a conductive coating layer 194, but the interconnector 190 does not necessarily have to include the coating layer 194. Also, in the above embodiment, the single cell 110 includes a reaction prevention layer 118, but the single cell 110 does not necessarily have to include the reaction prevention layer 118.

In the above embodiment, the single cell 110 is an anode-supported single cell, but it may be another type of single cell, such as an electrolyte-supported or metal-supported type. Also, in the above embodiment, the fuel cell stack 100 is a counterflow type fuel cell, but the fuel cell stack 100 may be another type of fuel cell, such as a coflow type.

In the above embodiment, the number of unit cells 110 (the number of power generation units 102) included in the fuel cell stack 100 is merely an example, and the number of unit cells 110 is determined appropriately depending on the output voltage required for the fuel cell stack 100. In addition, the materials constituting each member in the above embodiment are merely examples, and each member may be composed of other materials.

In the above embodiment, the subject is an SOFC that generates electricity by utilizing an electrochemical reaction between hydrogen contained in a fuel gas and oxygen contained in an oxidant gas. However, the technology disclosed in this specification can be similarly applied to an electrolysis cell unit, which is a constituent unit of a solid oxide electrolysis cell (SOEC) that generates hydrogen by utilizing an electrolysis reaction of water, and an electrolysis cell stack having a plurality of electrolysis cell units. The configurations of the electrolysis cell unit and the electrolysis cell stack are publicly known, for example, as described in JP 2016-81813 A, and will not be described in detail here, but are generally similar to the configurations of the power generation unit 102 and the fuel cell stack 100 in the above embodiment. That is, the fuel cell stack 100 in the above embodiment may be read as an electrolysis cell stack, the power generation unit 102 as an electrolysis cell unit, and the single cell 110 as an electrolysis single cell. However, when the electrolysis cell stack is operated, a voltage is applied between the electrodes so that the air electrode 114 is positive (anode) and the fuel electrode 116 is negative (cathode), and water vapor is supplied as a raw material gas through a manifold. As a result, a water electrolysis reaction occurs in each electrolysis cell unit, hydrogen gas is generated in the fuel chamber 176, and hydrogen is extracted to the outside of the electrolysis cell stack via the manifold. Even in an electrolysis cell stack with such a configuration, if a configuration similar to that of the above embodiment is adopted, damage to the joints of the joining members due to displacement of the gas passage member 27 can be suppressed.

In the above embodiment, a so-called flat plate type fuel cell stack has been used as an example, but the technology disclosed in this specification is not limited to the flat plate type and can be similarly applied to other types of fuel cell stacks (so-called cylindrical flat plate type and cylindrical type) as described below.

In the above embodiment, a solid oxide fuel cell (SOFC) has been described as an example, but the technology disclosed in this specification can also be applied to other types of fuel cells (or electrolytic cells), such as a polymer electrolyte fuel cell (PEFC), a phosphoric acid fuel cell (PAFC), and a molten carbonate fuel cell (MCFC). Furthermore, the technology disclosed in this specification is not limited to electrochemical reaction cell stacks, but can also be applied to a composite body including a first member having a first through hole and an upright portion, a cylindrical member connected to the upright portion, a second member, and a joining member that joins the first member and the second member.

22: Bolt 24: Nut 26: Gas through hole 27: Gas passage member 28: Main body 28a: Tip portion 29: Flange portion 100: Fuel cell stack 102: Power generation unit 103: Power generation block 104: Upper end plate 106: Lower end plate 107: End through hole 108: Communication hole 108B: Block communication hole 109: Bolt hole 110: Single cell 112: Electrolyte layer 114: Air electrode 116: Fuel electrode 118: Reaction prevention layer 120: Single cell separator 121: Through hole 124: Joint 125: Glass seal portion 130: Air electrode side frame 132: Oxidant gas supply communication hole 133: Oxidant gas exhaust communication hole 134: Air electrode side current collecting portion 140: Fuel electrode side frame 142: Fuel gas supply passage 143: Fuel gas exhaust passage 144: Fuel electrode side current collecting member 145: Electrode facing portion 146: Interconnector facing portion 147: Connection portion 149: Spacer 150: Flat plate portion 161: Oxidant gas supply manifold 162: Oxidant gas exhaust manifold 166: Air chamber 171: Fuel gas supply manifold 172: Fuel gas exhaust manifold 176: Fuel chamber 180: IC separator 189: Lower end plate 190: Interconnector 194: Covering layer 196: Conductive bonding material 197: Glass seal member 197a: Insertion hole 200: Insulating portion 210: Terminal separator 220: Upper end plate 310, 510: Flat portion 320, 520: Convex portion 322, 522: Outer convex portion 324, 524: Inner convex portion 410, 420: Terminal plate 510a: Overlap portion 520b: Connection periphery 523: Reinforcement portion 530: Standing portion 600: Reinforcement member 610: Flat plate portion 620: Cylinder portion FG: Fuel gas FOG: Fuel off-gas OG: Oxidizer gas OOG: Oxidizer off-gas

Claims (4)

a first member having a first through hole penetrating in a first direction and a cylindrical erected portion protruding to one side in the first direction and surrounding the first through hole;
a cylindrical member welded to the standing portion so as to communicate with the first through hole of the first member;
a second member disposed on the other side of the first member in the first direction and having a communication hole communicating with the first through hole ;
A joint member is disposed between the first member and the second member and disposed around the first through hole when viewed in the first direction.
When viewed in the first direction, the joining member is disposed outside a connection periphery of the first member, the connection periphery being a portion of the tubular member that surrounds an outline of a connection portion of the tubular member with the erected portion ,
an electrochemical reaction block including a plurality of electrochemical reaction units arranged in the first direction, each of the electrochemical reaction units having an electrochemical reaction unit cell including an electrolyte layer and an air electrode and an anode facing each other in the first direction with the electrolyte layer interposed therebetween;
the electrochemical reaction block is disposed on the other side of the first direction with respect to the first member and the tubular member;
the second member is disposed between the electrochemical reaction block and the first member;
The internal space of the cylindrical member serves as a gas flow path,
a manifold for exchanging gas between a specific electrode, which is at least one of the air electrode and the fuel electrode, in each of the electrochemical reaction units is formed so as to extend from the inside of the electrochemical reaction block to the cylindrical member via the first through hole of the first member and the communication hole of the second member , and the manifold is in communication with the gas flow path.
A complex characterized by: 2. The composite of claim 1 ,
The second member is disposed adjacent to the first member on the other side in the first direction.
A complex characterized by: In the complex according to claim 1 or 2,
The rigidity of an overlapping portion of the first member that overlaps with the joining member when viewed in the first direction is higher than the rigidity of the connection periphery portion.
A complex characterized by: The composite according to any one of claims 1 to 3,
The joining member has a second through hole formed therein surrounding the first through hole when viewed in the first direction,
When viewed in the first direction, at least on two imaginary straight lines extending in different directions from a center of a space surrounded by an outline of the connection portion of the tubular member, the separation distances between the connection portion of the tubular member and the joining member are different from each other.
A complex characterized by:

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