Electrochemical reaction cell stack

Abstract

To prevent a connection part between an end member and a gas passage member from being damaged.SOLUTION: An electrochemical reaction cell stack includes a reaction block including a single cell including an air electrode, an electrolyte layer, and a fuel electrode and having a gas flow path for supplying a gas to a periphery of the single cell, an end member disposed outside the reaction block, a gas passage member having a gas passage communicating with the gas flow path and connected to the end member, a reinforcing member including a holding portion holding the gas passage member, and one or a plurality of joining portions joining the end member and the reinforcing member, in which a length of at least one joining portion is larger than a thickness of the end member.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The technology disclosed herein relates to electrochemical reaction cell stacks. [Background technology]

[0002] Solid oxide fuel cells (hereinafter referred to as "SOFCs"), which have an electrolyte layer containing solid oxide, are known as one type of fuel cell that generates electricity using the electrochemical reaction between hydrogen and oxygen. SOFCs are used in the form of a fuel cell stack that includes a power generation block in which multiple structural units (electrochemical reaction units) are arranged in a predetermined direction. The fuel cell stack also includes end members that are arranged on the outside of the power generation block, and gas passage members that are connected to the end members and that supply gas to the inside of the power generation block.

[0003] When an external force is applied to the gas passage member, there is a concern that the connection between the end member and the gas passage member may be damaged, causing gas to leak to the outside. To prevent this from happening, a technique has been proposed in which a reinforcing member is provided that is fixed to the end member and supports the outer peripheral surface of the gas passage member (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-73494 Summary of the Invention [Problem to be solved by the invention]

[0005] In a fuel cell stack having the above configuration, there is a demand for more effective prevention of damage to the connection between the end member and the gas passage member, which would otherwise cause gas to leak to the outside.

[0006] These issues are also common to electrolysis cell stacks that include multiple electrolysis cell units, which are constituent elements of solid oxide electrolysis cells (hereinafter referred to as "SOECs") that generate hydrogen using the electrolysis reaction of water. Furthermore, these issues are not limited to SOFCs and SOECs, but are also common to other types of electrochemical reaction cell stacks.

[0007] This specification discloses a technique that can solve the above-mentioned problems. [Means for solving the problem]

[0008] The technology disclosed in this specification can be realized, for example, in the following forms. (1) The electrochemical reaction cell stack disclosed in this specification comprises a single cell having an air electrode, an electrolyte layer, and a fuel electrode, a reaction block having a gas flow path for supplying gas around the single cell, an end member arranged on the outside of the reaction block, a gas passage member having a gas passage communicating with the gas flow path and connected to the end member, a reinforcing member having a holding portion for holding the gas passage member, and one or more joints joining the end member and the reinforcing member, wherein the length of at least one of the joints is greater than the thickness of the end member.

[0009] By making the length of at least one joint longer than the thickness of the end member, the gas passage member is supported more firmly and stress generated at the connection between the end member and the gas passage member is reduced compared to when the length of the joint is shorter than the thickness of the end member, which makes it possible to prevent damage to the connection between the end member and the gas passage member and to prevent gas from leaking to the outside.

[0010] (2) In the electrochemical reaction cell stack described in (1) above, the joint may include a first joint and a second joint different from the first joint, and when viewed from the alignment direction of the end member and the reaction block, a first imaginary line extending along the length of the first joint and a second imaginary line extending along the length of the second joint may intersect.

[0011] With this configuration, even when forces are applied to the gas passage member from different directions, the gas passage member can be firmly supported, and stress generated at the connection portion between the end member and the gas passage member can be effectively reduced.

[0012] (3) In the electrochemical reaction cell stack described in (2) above, the length of the first joint portion and the length of the second joint portion may be greater than the thickness of the end member.

[0013] With this configuration, the gas passage member is supported more firmly, and stress generated in the connection portion between the end member and the gas passage member is effectively reduced.

[0014] (4) In the electrochemical reaction cell stack described in (2) above, the end member may be provided with a base disposed along the reaction block and to which the gas passage member is connected, and a reinforcing wall rising from the base on the opposite side of the reaction block, the reinforcing wall including a first reinforcing wall and a second reinforcing wall disposed in a different orientation from the first reinforcing wall, the first joint being a joint between the first reinforcing wall and the reinforcing member, and the second joint being a joint between the second reinforcing wall and the reinforcing member.

[0015] With this configuration, the end member is reinforced by the reinforcing wall, and the reinforcing member is joined to the reinforcing wall, which further firmly supports the gas passage member and effectively reduces stress generated at the connection between the end member and the gas passage member. Moreover, because the reinforcing member is supported by the first reinforcing wall and the second reinforcing wall, which are oriented in different directions, the gas passage member can be firmly supported even when forces are applied to the gas passage member from different directions, and stress generated at the connection between the end member and the gas passage member is effectively reduced.

[0016] (5) In the electrochemical reaction cell stack according to any one of (1) to (4) above, at least one of the joints may be formed by a plurality of welding points.

[0017] By forming the joints with a plurality of welding points, deformation of the end members due to heat generated in the joining process can be suppressed compared to when the joints are, for example, linear.

[0018] (6) In the electrochemical reaction cell stack described in any one of (1) to (5) above, the end member may be provided with a base portion arranged along the reaction block and to which the gas passage member is connected, and a reinforcing wall protruding from the base portion to the side opposite the reaction block, and at least one of the joint portions may be arranged at the leading edge of the reinforcing wall.

[0019] With this configuration, force applied to the gas passage member is less likely to be transmitted to the base portion via the reinforcing member, thereby suppressing deformation of the base portion and effectively reducing stress generated at the connection portion between the end member and the gas passage member.

[0020] (7) In the electrochemical reaction cell stack described in any one of (1) to (6) above, the reinforcing member may include a reinforcing rib that protrudes from the holding portion.

[0021] With this configuration, the reinforcing rib suppresses deformation of the holding portion, which in turn suppresses deformation of the gas passage member supported by the holding portion, thereby effectively reducing stress generated at the connection portion between the end member and the gas passage member.

[0022] The technology disclosed in this specification can be realized in various forms, for example, in the form of an electrochemical reaction cell stack and a manufacturing method thereof. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing the external configuration of a fuel cell stack according to a first embodiment; [Figure 2] FIG. 2 is a cross-sectional view showing the fuel cell stack of the first embodiment taken along line II-II in FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view showing the fuel cell stack of the first embodiment taken along line III-III in FIG. 1. [Figure 4] 2 is a cross-sectional view showing two adjacent electrochemical reaction units in the fuel cell stack of the first embodiment, taken along the same line as line II-II in FIG. 1; [Figure 5] FIG. 3 is a cross-sectional view showing two adjacent electrochemical reaction units in the fuel cell stack of the first embodiment, taken along the same line as line III-III in FIG. 1; [Figure 6] FIG. 1 is an enlarged cross-sectional view showing a peripheral portion of a gas passage member according to a first embodiment; [Figure 7] FIG. 2 is an enlarged perspective view showing the peripheral portion of the gas passage member of the first embodiment; [Figure 8] FIG. 10 is an enlarged bottom view showing the reinforcing member and a portion of the second end plate joined to the reinforcing member in the first embodiment. [Figure 9] FIG. 10 is an enlarged bottom view showing the reinforcing member and a portion of the second end plate joined to the reinforcing member in the second embodiment. [Figure 10] FIG. 10 is an enlarged perspective view showing the peripheral portion of a gas passage member according to a third embodiment; [Figure 11]FIG. 10 is an enlarged bottom view showing the reinforcing member and a portion of the second end plate joined to the reinforcing member in the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] A. First embodiment: A-1. Configuration of fuel cell stack 10: The first embodiment 1 will be described with reference to Figures 1 to 8. A fuel cell stack 10 (an example of an electrochemical reaction cell stack) of this embodiment is used in a solid oxide fuel cell having an electrolyte layer 112 containing a solid oxide.

[0025] (Overall configuration of fuel cell stack 10) 1 to 3, the fuel cell stack 10 includes a power generation block 100 (an example of a reaction block), an end separator 230, a first plate 232, a second plate 260, a first terminal plate 240, a second terminal plate 250, an insulating section 220, a first end plate 210, a second end plate 270 (an example of an end member), four gas passage members 280, and four reinforcing members 400. The first end plate 210, the insulating section 220, the end separator 230, the first terminal plate 240, the power generation block 100, the second terminal plate 250, the second plate 260, and the second end plate 270 have rectangular shapes of approximately the same size and are arranged in this order, stacked in a predetermined arrangement direction (the vertical direction in FIG. 2).

[0026] As shown in Fig. 1, the fuel cell stack 10 has bolt holes BH near each of the four corners, penetrating from the first end plate 210 to the second end plate 270. A bolt B is inserted into each bolt hole BH. A nut N is screwed onto both ends of each bolt B. These bolts B and nuts N fasten the members from the first end plate 210 to the second end plate 270 together. As shown in Figs. 2 and 3, the first plate 232 is supported by the terminal separator 230, the four gas passage members 280 are connected to the second end plate 270, and the four reinforcing members 400 are joined to the second end plate to hold the four gas passage members 280, respectively.

[0027] As shown in Figures 2 and 3, the power generation block 100 is composed of multiple (seven in this embodiment) electrochemical reaction units 100U (hereinafter sometimes abbreviated as "reaction units 100U") arranged in a predetermined arrangement direction (vertical direction in Figure 2).

[0028] (Overall configuration of 100U electrochemical reaction units) 4 and 5, the electrochemical reaction unit 100U includes a single cell 110, a single cell separator 120, an air electrode frame 130, an anode frame 140, an anode current collecting member 144, two interconnectors 190, and two IC separators 180. One IC separator 180, the air electrode frame 130, the single cell separator 120, the anode frame 140, and the other IC separator 180 are stacked in this order. The single cell 110 is supported by the single cell separator 120, the two interconnectors 190 are supported by the two IC separators 180, and the anode current collecting member 144 is disposed between the single cell 110 and the interconnectors 190.

[0029] 4 and 5, the IC separator 180 and the interconnector 190 are shared by two adjacent reaction units 100U. However, as shown in Fig. 2, the reaction unit 100U located at one end (the lower end in Fig. 2) of the multiple reaction units 100U does not have the IC separator 180 and the interconnector 190 adjacent to the fuel electrode frame 140, and the second terminal plate 250 overlaps the fuel electrode frame 140.

[0030] (single cell 110) The unit cell 110 includes an electrolyte layer 112, a cathode 114, and an anode 116. As shown in Figures 4 and 5, the cathode 114, the electrolyte layer 112, and the anode 116 are stacked in this order, with a reaction prevention layer 118 interposed between the electrolyte layer 112 and the cathode 114. The unit cell 110 of this embodiment is an anode-supported unit cell in which the anode 116 supports the other layers (electrolyte layer 112, cathode 114, and reaction prevention layer 118) that make up the unit cell 110.

[0031] The electrolyte layer 112 is a rectangular, flat member having one surface (the upper surface in FIGS. 4 and 5) on which the air electrode 114 is disposed and another surface (the lower surface in FIGS. 4 and 5) parallel to the first surface on which the anode 116 is disposed. The electrolyte layer 112 is a layer containing a solid oxide (e.g., YSZ (yttria-stabilized zirconia)). The cathode 114 is a layer having a rectangular shape smaller than that of the electrolyte layer 112 and containing, for example, a perovskite-type oxide (e.g., LSCF (lanthanum strontium cobalt iron oxide)). The anode 116 is a layer having a rectangular shape substantially the same as that of the electrolyte layer 112 and containing, 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 layer having a rectangular shape substantially the same as that of the air electrode 114 and containing, for example, GDC (gadolinium-doped ceria). The reaction prevention layer 118 has the function of preventing elements (e.g., Sr) diffused from the air electrode 114 from reacting with elements (e.g., Zr) contained in the electrolyte layer 112 to produce a highly resistive substance (e.g., SrZrO3).

[0032] (Single cell separator 120) As shown in Figures 4 and 5, the single cell separator 120 is a rectangular frame-like member having a substantially rectangular through-hole 121 near the center, and is made of, for example, metal. The plate thickness of the single cell separator 120 is relatively thin, for example, 0.05 mm or more and 0.2 mm or less. The peripheral portion of the through-hole 121 in the single cell separator 120 is joined to the peripheral portion of one surface of the electrolyte layer 112 (the surface on which the air electrode 114 is disposed: the upper surface in Figures 4 and 5) with a sealant 124. The sealant 124 is made of, for example, a brazing material (Ag brazing).

[0033] (Air electrode frame 130) 4 and 5, the cathode frame 130 is a rectangular frame-like member having a substantially rectangular through-hole 131 near the center, and is made of, for example, insulating ceramics (mica, etc.). The thickness of the cathode frame 130 is preferably 0.5 to 5 mm.

[0034] (fuel electrode frame 140) As shown in FIG. 5, the fuel electrode frame 140 is a rectangular frame-like member having a substantially rectangular through-hole 141 near the center, and is made of, for example, metal.

[0035] (IC separator 180) As shown in FIGS. 4 and 5, IC separator 180 is a rectangular frame-shaped member having a through-hole 181 near the center, and is made of, for example, metal.

[0036] (Interconnector 190 and anode current collecting member 144) 4 and 5, the interconnector 190 includes a rectangular flat plate portion 191, a plurality of plate-like air electrode current collectors 192 protruding from one surface of the flat plate portion 191 toward the air electrode 114, and a coating layer 193. The flat plate portion 191 and the air electrode current collectors 192 are electrically conductive and made of a metal (e.g., ferritic stainless steel). The coating layer 193 is electrically conductive and is disposed so as to cover the surface of the air electrode current collector 192 and the surface of the flat plate portion 191 on which the air electrode current collector 192 is disposed. The flat plate portion 191 is joined to the periphery of the through hole 181 in the IC separator 180, for example, by welding.

[0037] The anode current collecting member 144 is a member that connects the interconnector 190 and the anode 116, and is formed of a conductive material such as nickel, a nickel alloy, or stainless steel. As shown in Figures 4 and 5, the anode current collecting member 144 has an interconnector facing portion 146, an electrode facing portion 145 that is parallel to the interconnector facing portion 146, and a connecting portion 147 that connects the electrode facing portion 145 and the interconnector facing portion 146, and has an overall U-shape. The electrode facing portion 145 is in contact with the anode 116, and the interconnector facing portion 146 is in contact with a flat portion 191 of the interconnector 190.

[0038] As described above, the interconnector 190 is shared by two adjacent reaction units 100U. More specifically, as shown in Figures 4 and 5, the air electrode current collecting part 192 is joined to the air electrode 114 of the unit cell 110 provided in one of the two adjacent reaction units 100U via a conductive bonding material 196 made of, for example, a spinel-type oxide, and is thereby electrically connected to the air electrode 114. The flat plate part 191 is electrically connected to the anode 116 of the unit cell 110 provided in the other of the two adjacent reaction units 100U via an anode current collecting member 144. This ensures electrical continuity between the two adjacent reaction units 100U.

[0039] However, as described above, the reaction unit 100U located at one end (the lower end in FIG. 2) of the multiple reaction units 100U does not have an interconnector 190 on the fuel electrode 116 side. The fuel electrode 116 included in this reaction unit 100U is connected to the second terminal plate 250 via the fuel electrode current collecting member 144.

[0040] A spacer 149 made of, for example, mica is disposed between the electrode facing portion 145 and the interconnector facing portion 146. This allows the anode current collecting member 144 to follow deformation of the reaction unit 100U due to temperature cycles and fluctuations in reactant gas pressure, and good electrical connection between the anode 116 and the interconnector 190 (or second terminal plate 250) via the anode current collecting member 144 is maintained.

[0041] (Air chamber 313 and fuel chamber 323) 4 and 5, the space partitioned by the single cell separator 120, the single cell 110, the air electrode frame 130, the IC separator 180, and the interconnector 190 faces the air electrode 114 and serves as an air chamber 313 (an example of a gas flow path) through which the oxidant gas OG flows. The air electrode frame 130 partitions the entire periphery of the air chamber 313 from the external space and seals the gap between the single cell separator 120 and the IC separator 180, thereby preventing gas from leaking from the air chamber 313 to the external space.

[0042] The space partitioned by the single cell separator 120, the single cell 110, the fuel electrode frame 140, the IC separator 180, and the interconnector 190 faces the fuel electrode 116 and serves as a fuel chamber 323 (an example of a gas flow path) through which the fuel gas FG flows. The fuel electrode frame 140 partitions the entire periphery of the fuel chamber 323 from the external space, and seals the gap between the single cell separator 120 and the IC separator 180, thereby preventing gas from leaking from the fuel chamber 323 to the external space.

[0043] The single cell separator 120 separates the air chamber 313 and the fuel chamber 323, thereby preventing gas leakage (cross leakage) from the air electrode 114 side to the fuel electrode 116 side or from the fuel electrode 116 side to the air electrode 114 side around the single cell 110. In addition, the IC separator 180 and the interconnector 190 prevent gas leakage between adjacent reaction units 100U.

[0044] (First end plate 210) The first end plate 210 is a member formed by pressing (bending) a single plate-like member, and is formed of a conductive material such as stainless steel. As shown in FIGS. 1 to 3 , the first end plate 210 includes a rectangular, frame-like flat portion 211 having a through-hole 212 near the center, and an outer convex portion 213 and an inner convex portion 214 that protrude from the flat portion 211 in the direction opposite the insulating portion 220 (upward in FIG. 2 ). The flat portion 211 has holes that form the bolt holes BH described above. The outer convex portion 213 protrudes from the outer periphery of the flat portion 211. The outer convex portion 213 is formed around the entire outer periphery of the flat portion 211. The inner convex portion 214 protrudes from the inner periphery of the flat portion 211. The inner convex portion 214 is formed around the entire inner periphery of the flat portion 211.

[0045] (insulating part 220) Insulating section 220 is a rectangular frame-shaped member with a through-hole near the center, and is made of, for example, an insulating material. As shown in Figure 2, insulating section 220 is sandwiched between first end plate 210 and end separator 230, thereby ensuring insulation between first end plate 210 and end separator 230.

[0046] (Terminal separator 230) As shown in FIGS. 2 and 3, the terminal separator 230 is a rectangular frame-shaped member having a through-hole 231 near the center, and is made of, for example, metal.

[0047] (First Plate 232) The first plate 232 is a rectangular, flat member made of a conductive material such as stainless steel. As shown in Figures 2 and 3, the first plate 232 is joined by welding, for example, to the periphery of the through-hole 231 in the terminal separator 230. The terminal separator 230 and the first plate 232 separate the power generating block 100 from the external space of the fuel cell stack 10.

[0048] The first plate 232 is connected to an interconnector 190 provided in the reaction unit 100U arranged at the other end (the upper end in Figure 2) of the multiple reaction units 100U that make up the power generation block 100 via a connecting member having the same structure as the anode current collecting member 144, thereby electrically connecting this reaction unit 100U and the first plate 232.

[0049] (First terminal plate 240) The first terminal plate 240 is a rectangular frame-shaped member having a through-hole 241 near the center, and is made of a conductive material such as ferritic stainless steel that forms an alumina oxide coating on its surface. The first terminal plate 240 is electrically connected to the reaction unit 100U arranged at the other end (the upper end in FIG. 2) of the multiple reaction units 100U that make up the power generation block 100 via a first plate 232 and a terminal separator 230. One end (the right end in FIG. 2) of the first terminal plate 240 protrudes laterally from the power generation block 100, and this protruding portion functions as a positive output terminal for the fuel cell stack 10.

[0050] (2nd terminal plate 250) The second terminal plate 250 is a rectangular plate-shaped member made of a conductive material such as ferritic stainless steel that forms an alumina oxide coating on its surface. As described above, the second terminal plate 250 is connected to the anode 116 provided in the reaction unit 100U arranged at one end (the lower end in FIG. 2 ) of the multiple reaction units 100U via the anode current collecting member 144, thereby electrically connecting this reaction unit 100U to the second terminal plate 250. One end (the right end in FIG. 2 ) of the second terminal plate 250 protrudes laterally from the power generation block 100, and this protruding portion functions as the negative output terminal of the fuel cell stack 10.

[0051] (Second plate 260) Second plate 260 is a rectangular, flat member made of, for example, an insulating material. The peripheral edge of second plate 260 is sandwiched between second terminal plate 250 and second end plate 270, thereby ensuring insulation between second terminal plate 250 and second end plate 270.

[0052] (Second end plate 270) Second end plate 270 is a member formed by pressing (bending) a single plate-like member, and is formed of a conductive material such as stainless steel. Second end plate 270 includes a rectangular, frame-like flat portion 271 (an example of a base) having a through-hole 272 near the center, an outer reinforcing wall 291 (an example of a reinforcing wall) and an inner reinforcing wall 296 (an example of a reinforcing wall) protruding from flat portion 271 in the direction opposite second terminal plate 250 (downward in FIGS. 2, 3, and 6), and four first retaining cylindrical portions 274. Through-hole 272 is a hole defined by a rectangular hole edge.

[0053] The flat portion 271 is placed on the power generation block 100 via the second terminal plate 250 and the second plate 260, and is disposed along the power generation block 100. The flat portion 271 has four first retaining holes 273 for retaining four gas passage members 280, respectively. Each of the four first retaining cylindrical portions 274 is a cylindrical portion that extends outward from the edge of each of the four first retaining holes 273, i.e., toward the opposite side from the power generation block 100 (downward in FIG. 6 ). The outer reinforcing wall 291 protrudes from the outer peripheral edge of the flat portion 271. The inner reinforcing wall 296 protrudes from the inner peripheral edge of the flat portion 271, i.e., from the edge of the through-hole 272.

[0054] As shown in Fig. 7, the outer reinforcing wall 291 includes a first outer reinforcing wall 292 (an example of a first reinforcing wall) and a second outer reinforcing wall 293 (an example of a second reinforcing wall) that extends in a direction different from that of the first reinforcing wall. The first outer reinforcing wall 292 is a wall that extends perpendicularly to one of the four sides that constitute the outer edge of the flat surface portion 271. The second outer reinforcing wall 293 is a wall that extends from another side that is perpendicular to the side on which the first outer reinforcing wall 292 is disposed, among the four sides that constitute the outer edge of the flat surface portion 271. The second outer reinforcing wall 293 is disposed perpendicularly to the flat surface portion 271 and the first outer reinforcing wall 292. A first reinforcing rib 294 protrudes from a tip edge 292E of the first outer reinforcing wall 292 opposite the flat surface portion 271, in a direction opposite to the inner reinforcing wall 296.

[0055] The inner reinforcing wall 296 includes a first inner reinforcing wall 297 (an example of a first reinforcing wall) and a second inner reinforcing wall 298 extending in a direction different from that of the first reinforcing wall. The first inner reinforcing wall 297 is a wall extending perpendicular to the flat surface portion 271 from one of the four sides constituting the inner peripheral edge of the flat surface portion 271 (the hole edge of the through hole 272). The first inner reinforcing wall 297 is disposed parallel to the first outer reinforcing wall 292. The second inner reinforcing wall 298 is a wall extending from another side of the four sides constituting the inner peripheral edge of the flat surface portion 271 (the hole edge of the through hole 272) that is perpendicular to the side on which the first inner reinforcing wall 297 is disposed. The second inner reinforcing wall 298 is disposed parallel to the second outer reinforcing wall 293. A second reinforcing rib 299 protrudes from a tip edge 297E of the first inner reinforcing wall 297 opposite the flat portion 271 in a direction opposite to the outer reinforcing wall 291.

[0056] The second end plate 270 is required to press and hold the power generation block 100 against the first end plate 210. For this reason, it is necessary to keep the flat surface 271 as flat as possible. The reinforcing walls 291, 296 serve to reinforce the flat surface 271 and prevent deformation of the flat surface 271. The first reinforcing rib 294 only needs to be disposed in at least the portion of the first outer reinforcing wall 292 where the reinforcing member 400 is joined, and may be disposed over the entire length of the first outer reinforcing wall 292. The same applies to the second reinforcing rib 299.

[0057] As described above, the second end plate 270 is formed by pressing (bending) a single plate-like member, and each part that constitutes the second end plate 270, i.e., the flat portion 271, the outer reinforcing wall 291, the inner reinforcing wall 296, the first reinforcing rib 294, and the second reinforcing rib 299, all have the same thickness T0.

[0058] (Manifolds 311, 312, 321, 322) 1, 2, and 3, the fuel cell stack 10 has four holes that penetrate from the power generation block 100 to the second end plate 270. The four holes are an oxidant gas supply manifold 311 (an example of a gas flow path), an oxidant gas discharge manifold 312 (an example of a gas flow path), a fuel gas supply manifold 321 (an example of a gas flow path), and a fuel gas discharge manifold 322 (an example of a gas flow path).

[0059] 2, the oxidant gas supply manifold 311 is a gas flow path that supplies the oxidant gas OG introduced from outside the fuel cell stack 10 to the air chamber 313 of each reaction unit 100U. The oxidant gas discharge manifold 312 is a gas flow path that discharges the oxidant off-gas OOG discharged from the air chamber 313 of each reaction unit 100U to the outside of the fuel cell stack 10. For example, air is used as the oxidant gas OG. The oxidant gas supply manifold 311 and the oxidant gas discharge manifold 312 are arranged on opposite sides of the air chamber 313.

[0060] As shown in Fig. 3, the fuel gas supply manifold 321 is a gas flow path that supplies fuel gas FG introduced from outside the fuel cell stack 10 to the fuel chamber 323 of each reaction unit 100U. The fuel gas discharge manifold 322 is a gas flow path that discharges fuel off-gas FOG discharged from the fuel chamber 323 of each reaction unit 100U to the outside of the fuel cell stack 10. For example, hydrogen-rich gas obtained by reforming city gas is used as the fuel gas FG. The fuel gas supply manifold 321 and the fuel gas discharge manifold 322 are arranged on opposite sides of the fuel chamber 323.

[0061] (Gas passage member 280) As shown in FIGS. 2, 3, and 6, each of the four gas passage members 280 includes a main body 281 and a flange 282. The main body 281 is cylindrical and open at both ends. The internal space of the main body 281 included in each of the four gas passage members 280 serves as a gas passage 283 that communicates with each of the four manifolds 311, 312, 321, and 322. The flange 282 is provided so as to protrude outward from one end (the lower end in FIG. 6) of the main body 281. One end (the upper end in FIG. 6) of the main body 281 included in each of the four gas passage members 280 is inserted into the first holding cylinder 274 and joined to the first holding cylinder 274 by, for example, welding. The internal space of the main body 281 communicates with the manifolds 311, 312, 321, and 322, respectively. Gas piping for supplying or discharging gas is connected to each main body portion 281. As shown in Figures 1 and 7, the flange portion 282 has a plurality of bolt holes 284. The flange portion 282 is fixed by bolts to an external device, for example, a casing of a gas supply device for supplying fuel gas and oxidant gas to the fuel cell stack 10.

[0062] (reinforcing member 400) The four reinforcing members 400 are made of metal, hold the main bodies 281 of the four gas passage members 280, and are joined to the second end plate 270. The reinforcing members 400 are disposed at intervals from the flat surface portion 271 and the first holding cylindrical portion 274, i.e., the portions of the second end plate 270 that hold the gas passage members 280, and are joined to the second end plate 270.

[0063] As shown in FIG. 6 , each reinforcing member 400 includes a holding portion 401 that holds the main body 281 and a second holding tube portion 405 extending from the holding portion 401. As shown in FIGS. 7 and 8 , the holding portion 401 is a flat plate-like portion that includes a holding portion main body 402 and an extension portion 403 extending from the holding portion main body 402. The holding portion main body 402 is a rectangular plate and is disposed parallel to and spaced apart from the flat portion 271 of the second end plate 270. The holding portion main body 402 has two parallel sides. One of the two sides is joined by welding to the leading edge 292E of the first outer reinforcing wall 292 and the first reinforcing rib 294, and the other is joined by welding to the leading edge 297E of the first inner reinforcing wall 297 and the second reinforcing rib 299. The holder body 402 has a second holder hole 404 through which the body 281 of the gas passage member 280 can be inserted.

[0064] The extension portion 403 is a rectangular plate-like portion extending from a side of the holder main body 402 other than the two sides welded to the first outer reinforcing wall 292 and the first inner reinforcing wall 297. The extension portion 403 is disposed at one end of the holder main body 402 on the first inner reinforcing wall 297 side. The tip of the extension portion 403 is joined by welding to a tip edge 293E of the second outer reinforcing wall 293 on the opposite side from the flat portion 271. As shown in FIG. 8 , the extension portion 403 is disposed so as to avoid the nuts N used to fasten the members from the first end plate 210 to the second end plate 270. In other words, the reinforcing member 400 is disposed so as not to cover the nuts N, and the space defined by the reinforcing member 400 and the outer reinforcing wall 291 allows an operator to insert a tool or the like to tighten or loosen the nuts N.

[0065] 6, the second holding cylinder portion 405 is a cylindrical portion that extends outward from the edge of the second holding hole 404, that is, on the opposite side from the second end plate 270. The main body portion 281 is inserted into the second holding hole 404 and the interior of the second holding cylinder portion 405, and is joined to the second holding cylinder portion 405 by welding. The second holding cylinder portion 405 supports a portion of the main body portion 281 that is different from the tip portion that is joined to the first holding cylinder portion 274.

[0066] As shown in FIG. 8 , a first outer joint 501 (first joint) at which the retaining portion 401 is joined to the first outer reinforcing wall 292 and the first reinforcing rib 294 extends in an elongated shape along the first outer reinforcing wall 292. A length T1, which is the distance between both ends of the first outer joint 501, is greater than a thickness T0 of the second end plate 270. Furthermore, a first inner joint 502 (first joint) at which the retaining portion 401 is joined to the first inner reinforcing wall 297 and the second reinforcing rib 299 extends in an elongated shape along the first inner reinforcing wall 297. A length T2, which is the distance between both ends of the first inner joint 502, is greater than a thickness T0 of the second end plate 270. A second joint 503 at which the extension portion 403 is joined to the second outer reinforcing wall 293 extends in an elongated shape along the second outer reinforcing wall 293. Length T3, which is the distance between both ends of second joint 503, is greater than thickness T0 of second end plate 270. When reinforcing member 400 and second end plate 270 are linearly welded together as in this embodiment, the "joint" refers to the area where the reinforcing member and end plate are fixed together, and does not include the area where reinforcing member 400 and second end plate 270 are simply in contact with each other without being fixed together.

[0067] When connecting flange portion 282 of gas passage member 280 to an external device by bolting, a force may be applied to gas passage member 280 in a direction intersecting the axial direction of main body portion 281 (the vertical direction in FIG. 6 ) due to an error in the installation position of the external device relative to fuel cell stack 10, a manufacturing tolerance of gas passage member 280, etc. If such a force is applied, the connection portion between second end plate 270 and gas passage member 280, that is, the joint portion between first holding cylindrical portion 274 and main body portion 281, may be damaged, resulting in a risk of gas leakage to the outside. To prevent this from happening, reinforcing member 400 is provided to hold gas passage member 280 and be joined to second end plate 270.

[0068] By making lengths T1, T2, T3 of joints 501, 502, 503 between reinforcing member 400 and second end plate 270 longer than thickness T0 of second end plate 270, the rigidity of joints 501, 502, 503 is increased compared to when the length of the joint is shorter than the thickness of the end plate. This makes it possible to firmly support gas passage member 280, and reduces stress generated at the connection portion between second end plate 270 and gas passage member 280. This makes it possible to prevent damage to the connection portion between second end plate 270 and gas passage member 280, and to prevent gas from leaking to the outside. In particular, when force is applied in a direction perpendicular to the longitudinal direction of joints 501, 502, 503, second end plate 270 is likely to deform and stress at the connection portion between second end plate 270 and gas passage member 280 is likely to increase. However, even in such a case, by making lengths T1, T2, T3 of joints 501, 502, 503 greater than thickness T0 of second end plate 270 and increasing the rigidity of joints 501, 502, 503, deformation of second end plate 270 can be suppressed and stress generated at the connection portion between second end plate 270 and gas passage member 280 can be reduced.

[0069] Second end plate 270 is reinforced by reinforcing walls 291, 296, and reinforcing member 400 is joined to reinforcing walls 291, 296. This further firmly supports gas passage member 280, effectively reducing stress generated in the connection portion between second end plate 270 and gas passage member 280.

[0070] Furthermore, the reinforcing member 400 is joined to the leading edges 292E, 293E, and 297E of the reinforcing walls 291 and 296 that are farthest from the flat portion 271. This makes it difficult for force applied to the gas passage member 280 to be transmitted to the flat portion 271, thereby suppressing deformation of the flat portion 271. Furthermore, heat generated from the power generation block 100 during operation of the fuel cell stack 10 is difficult to be transmitted to the reinforcing member 400, thereby suppressing deformation of the reinforcing member 400 due to heat. In addition, the distance between the position where the reinforcing member 400 holds the main body portion 281 (the joint between the second holding cylindrical portion 405 and the main body portion 281) and the connection between the second end plate 270 and the main body portion 281 is large. Therefore, even if an external force is applied to the reinforcing member 400, a larger force is required to rotationally deform the gas passage member 280 due to the external force. This suppresses deformation of the gas passage member 280.

[0071] When viewed from the arrangement direction of the second end plate 270 and the power generation block 100 (the Z-axis direction in FIG. 8), a first outer imaginary line L1 (an example of a first imaginary line) extending along the length of the first outer joint 501 and a second imaginary line L3 extending along the length of the second joint 503 intersect perpendicularly. Furthermore, a first inner imaginary line L2 (an example of a first imaginary line) extending along the length of the first inner joint 502 and the second imaginary line L3 intersect perpendicularly.

[0072] With this configuration, even when force is applied to gas passage member 280 from either the direction along joints 501 and 502 (X-axis direction in FIG. 8) or the direction along second joint 503 (Y-axis direction in FIG. 8), gas passage member 280 can be firmly supported, and stress generated at the connection portion between second end plate 270 and gas passage member 280 is effectively reduced.

[0073] A-2. Operation of fuel cell stack 10: 2, the oxidizing gas OG is supplied to the air chamber 313 through the gas passage member 280 and the oxidizing gas supply manifold 311. Also, as shown in FIG. 3, the fuel gas FG is supplied to the fuel chamber 323 through the gas passage member 280 and the fuel gas supply manifold 321.

[0074] When an oxidant gas OG is supplied to the air chamber 313 of each reaction unit 100U and a fuel gas FG is supplied to the fuel chamber 323, power is generated in the single cell 110 by an electrochemical reaction between the oxidant gas OG and the fuel gas FG. This power generation reaction is exothermic. As described above, the interconnector 190 is shared by two adjacent reaction units 100U, and the interconnector 190 ensures electrical continuity between the two adjacent reaction units 100U. In other words, the multiple reaction units 100U included in the fuel cell stack 10 are electrically connected in series. Furthermore, a second terminal plate 250 is electrically connected to the reaction unit 100U located at one end (the lower end in FIG. 2 ) of the multiple reaction units 100U, and a first terminal plate 240 is electrically connected to the reaction unit 100U located at the other end (the upper end in FIG. 2 ). As a result, electrical energy generated in each reaction unit 100U is extracted from the terminal plates 240, 250, which function as output terminals of the fuel cell stack 10. Since SOFCs generate electricity at relatively high temperatures (e.g., 700°C to 1000°C), after startup, the fuel cell stack 10 may be heated by a heater (not shown) until the high temperature can be maintained using the heat generated by power generation.

[0075] 2, the oxidant off-gas OOG discharged from the air chamber 313 of each reaction unit 100U to the oxidant gas discharge manifold 312 is discharged to the outside of the fuel cell stack 10 through the internal space of the main body 281. Also, as shown in FIG. 3, the fuel off-gas FOG discharged from the fuel chamber 323 of each reaction unit 100U to the fuel gas discharge manifold 322 is discharged to the outside of the fuel cell stack 10 through the internal space of the main body 281.

[0076] A-3. Advantages of this embodiment: As described above, the fuel cell stack 10 of this embodiment comprises a single cell 110 having an air electrode 114, an electrolyte layer 112, and a fuel electrode 116, a power generation block 100 having gas flow paths (air chamber 313, fuel chamber 323, and manifolds 311, 312, 321, 322) for supplying gas around the single cell 110, a second end plate 270 arranged on the outside of the power generation block 100, a gas passage member 280 having a gas passage 283 communicating with the manifolds 311, 312, 321, 322 and connected to the second end plate 270, a reinforcing member 400 having a holding portion 401 that holds the gas passage member 280, and joining portions 501, 502, 503 that join the second end plate 270 and the reinforcing member 400. The lengths T1, T2, and T3 of the joints 501, 502, and 503 are greater than the thickness T0 of the second end plate 270.

[0077] By making lengths T1, T2, T3 of joints 501, 502, 503 greater than thickness T0 of second end plate 270, gas passage member 280 is supported more firmly and stress generated at the connection portion between second end plate 270 and gas passage member 280 is reduced compared to when the length of the joint is shorter than the thickness of the end plate. This makes it possible to prevent damage to the connection portion between second end plate 270 and gas passage member 280 and to prevent gas from leaking to the outside.

[0078] The joints 501, 502, and 503 include a first outer joint 501, a first inner joint 502, and a second joint 503 that is different from the joints 501 and 502. When viewed from the direction in which the second end plate 270 and the power generation block 100 are arranged, a first outer imaginary line L1 extending along the length of the first outer joint 501 and a second imaginary line L3 extending along the length of the second joint 503 intersect perpendicularly. Furthermore, a first inner imaginary line L2 extending along the length of the first inner joint 502 and the second imaginary line L3 intersect perpendicularly.

[0079] With this configuration, even when force is applied to gas passage member 280 from different directions, gas passage member 280 can be firmly supported, and stress generated at the connection portion between second end plate 270 and gas passage member 280 is effectively reduced.

[0080] The second end plate 270 is disposed along the power generation block 100 and includes a flat portion 271 to which the gas passage member 280 is connected, and reinforcing walls 291, 296 rising from the flat portion 271 on the side opposite the power generation block 100. The reinforcing walls 291, 296 include a first outer reinforcing wall 292, a first inner reinforcing wall 297, and a second outer reinforcing wall 293 that is disposed in a different orientation from the reinforcing walls 292, 297. A first outer joint 501 is the joint between the reinforcing member 400 and the first outer reinforcing wall 292, a first inner joint 502 is the joint between the reinforcing member 400 and the first inner reinforcing wall 297, and a second joint 503 is the joint between the reinforcing member 400 and the second outer reinforcing wall 293.

[0081] According to this configuration, second end plate 270 is reinforced by reinforcing walls 292, 297, and reinforcing member 400 is joined to reinforcing walls 292, 297, which further firmly supports gas passage member 280 and effectively reduces stress generated at the connection between second end plate 270 and gas passage member 280. Furthermore, because reinforcing member 400 is supported by first outer reinforcing wall 292, first inner reinforcing wall 297, and second outer reinforcing wall 293, which is arranged in a different direction from these, gas passage member 280 can be firmly supported even when force is applied to gas passage member 280 from different directions, and stress generated at the connection between second end plate 270 and gas passage member 280 is effectively reduced.

[0082] In addition, joints 501, 502, 503 are arranged at the leading edges 292E, 293E, 297E of the reinforcing walls 292, 297.

[0083] With this configuration, force applied to gas passage member 280 is less likely to be transmitted to flat portion 271 via reinforcing member 400, thereby suppressing deformation of flat portion 271. This effectively reduces stress generated in the connection portion between second end plate 270 and gas passage member 280.

[0084] B. Second embodiment The second embodiment will be described with reference to Fig. 9. This embodiment differs from the first embodiment in the configuration of a first outer joint portion 501B.

[0085] The reinforcing member 400B of this embodiment has the same configuration as the first embodiment and is joined to the second end plate 270 by welding. A first outer joint 501B (first joint) where the retaining portion 401 is joined to the first outer reinforcing wall 292 and the first reinforcing rib 294 is formed by a plurality of spot-shaped welds 501P lined up in a row along the first outer reinforcing wall 292. Each weld 501P is formed by, for example, spot welding. The length T1B of the first outer joint 501B, which is represented by the length of the row of the plurality of welds 501P, is greater than the thickness T0 of the second end plate 270. The length of the row of the plurality of welds 501P is represented by the distance from the edge of a weld 501P located at one end opposite the other adjacent welds 501P to the edge of a weld 501P located at the other end opposite the other adjacent welds 501P.

[0086] When viewed from the direction in which the second end plate 270 and the power generation block 100 are aligned, the first outer virtual straight line L1B extending in the longitudinal direction of the first outer joint 501B, i.e., along the row of multiple welding points 501P, and the second virtual straight line L3 extending along the longitudinal direction of the second joint 503 intersect perpendicularly.

[0087] The other configurations are the same as those in the first embodiment, so the same components are given the same reference numerals and the description thereof will be omitted.

[0088] In this way, by forming first outer joint portion 501B by a plurality of welding points 501P, deformation of second end plate 270 due to heat generated in the joining process can be suppressed compared to when the joint portion is linear.

[0089] C. Third embodiment The third embodiment will be described with reference to Fig. 10. This embodiment differs from the first embodiment in that a reinforcing member 400C includes a third reinforcing rib 406 (an example of a reinforcing rib).

[0090] The reinforcing member 400C of this embodiment includes a holding portion 401 and a second holding cylindrical portion 405, similar to the first embodiment.

[0091] The third reinforcing rib 406 protrudes from the retaining portion 401 on the side opposite to the second end plate 270. The third reinforcing rib 406 protrudes from a side edge of the retaining portion 401 that is arranged along the first inner reinforcing wall 297. A portion of the third reinforcing rib 406 is arranged along the first inner joint portion 502, and reinforces the vicinity of the portion of the retaining portion 401 where the first inner joint portion 502 is arranged.

[0092] The other configurations are the same as those in the first embodiment, so the same components are given the same reference numerals and the description thereof will be omitted.

[0093] With this configuration, third reinforcing rib 406 suppresses deformation of holding portion 401, which in turn suppresses deformation of gas passage member 280 supported by holding portion 401. This effectively reduces stress generated in the connection portion between second end plate 270 and gas passage member 280.

[0094] D. Fourth embodiment The fourth embodiment will be described with reference to Fig. 11. This embodiment differs from the first embodiment in the shape of a reinforcing member 400D.

[0095] The reinforcing member 400D includes a holding portion 401D that holds the main body portion 281, and a second holding cylinder portion 405. The holding portion 401D is a rectangular, flat plate-shaped portion. The holding portion 401D has a second holding hole 404 through which the main body portion 281 of the gas passage member 280 can be inserted. The second holding cylinder portion 405 is a cylindrical portion that extends from the hole edge of the second holding hole 404, as in the first embodiment, and is joined to the main body portion 281 by welding.

[0096] The holding portion 401D further has a jig insertion hole 407. The jig insertion hole 407 is a through-hole disposed at a position corresponding to a nut N for fastening the members from the first end plate 210 to the second end plate 270. An operator can insert a jig or the like into this jig insertion hole 407 to tighten or loosen the nut N.

[0097] One of the four sides of the retaining portion 401D is joined by welding to the first outer reinforcing wall 292 and the first reinforcing rib 294, and the other side perpendicular to this side is joined by welding to the second outer reinforcing wall 293.

[0098] A first outer joint 501D (first joint), which is a joint between the retaining portion 401D and the first outer reinforcing wall 292 and the first reinforcing rib 294, extends in an elongated shape along the first outer reinforcing wall 292. A length T1D, which is represented by the distance between both ends of the first outer joint 501D, is greater than a thickness T0 of the second end plate 270. A second joint 503D, which is a joint between the retaining portion 401D and the second outer reinforcing wall 293, extends in an elongated shape along the second outer reinforcing wall 293. A length T3D, which is represented by the distance between both ends of the second joint 503D, is greater than a thickness T0 of the second end plate 270.

[0099] When viewed from the alignment direction of the second end plate 270 and the power generation block 100, the first outer virtual straight line L1D extending in the longitudinal direction of the first outer joint 501D and the second virtual straight line L3D extending along the longitudinal direction of the second joint 503D intersect perpendicularly.

[0100] Providing jig insertion hole 407 in holding portion 401D eliminates the need to position holding portion 401D so as to avoid nuts N. This allows joining portions 501D and 503D to be longer than when the holding portion is positioned so as to avoid parts such as nuts N that fasten members that make up fuel cell stack 10, and enables reinforcing member 400D to be firmly joined to second end plate 270.

[0101] E. Variations (1) In the above embodiment, the number of joints 501, 501B, 501D, 502, 503, 503D that join the reinforcing members 400, 400B, 400C, 400D to the second end plate 270 is three, but the number of joints may be two or less or four or more. (2) In the above embodiment, the lengths T1, T1B, T1D, T2, T3, and T3D of all of the joints 501, 501B, 501D, 502, 503, and 503D were greater than the thickness T0 of the second end plate 270, but it is also acceptable for the lengths of some of the joints to be greater than the thickness of the end member. (3) In the above embodiment, the first outer imaginary lines L1, L1B, and L1D (first imaginary lines) and the first inner imaginary line L2 intersect perpendicularly with the second imaginary lines L3 and L3D. However, the angle between the first imaginary line and the second imaginary line does not have to be 90°. Furthermore, the first imaginary line and the second imaginary line do not necessarily have to intersect. As long as the first joints and the second joints are oriented in different directions, the gas passage member can be firmly supported even when forces are applied to the gas passage member from different directions. Alternatively, all of the joints may be arranged parallel to one another. (4) In the above embodiment, the joints 501, 501B, 501D, 502, 503, and 503D were joined to the leading edges of the reinforcing walls 291 and 296, but the joints may be joined to a location on the end member other than the leading edges of the reinforcing walls. (5) In the above embodiment, the second end plate 270 includes the outer reinforcing wall 291 and the inner reinforcing wall 296. However, the reinforcing walls may be disposed in any position within the end member. For example, the reinforcing walls may be disposed on part of the outer edge or inner edge of the end member, or may be disposed on the outer edge or at a position different from the outer edge of the end member. Alternatively, the end member may not include a reinforcing wall. (6) In the above embodiment, the reinforcing members 400, 400B, 400C, and 400D were joined to the first outer reinforcing wall 292, the second outer reinforcing wall 293, and the first inner reinforcing wall 297, but the joining positions of the reinforcing members relative to the end members are arbitrary, and for example, they may be joined only to the outer reinforcing wall or only to the inner reinforcing wall. (7) In the above embodiment, the reinforcing ribs 294, 299 protrude from the first outer reinforcing wall 292 and the first inner reinforcing wall 297, respectively. However, the arrangement of the reinforcing ribs is optional. For example, the reinforcing ribs may be arranged only on the outer reinforcing wall or only on the inner reinforcing wall. Alternatively, the end member may not have reinforcing ribs. (8) In the above embodiment, all portions constituting the second end plate 270 have the same thickness T0. However, the end member may have different thicknesses depending on the portion. In this case, the thickness of the end member to be compared with the length of the joint is the thickness of the portion of the end member that is joined to the reinforcing member by the joint. (9) In the first to third embodiments, examples were shown in which the extension portion 403 was a rectangular plate-like piece, but the shape of the extension portion is arbitrary, and for example, the width of the extension portion may increase as it approaches the end member. (10) In the third embodiment, the third reinforcing rib 406 protruded from the side edge of the retaining portion 401 arranged along the first inner reinforcing wall 297, but the reinforcing rib may protrude from another side edge of the retaining portion, or may protrude from a position different from the side edge. (11) In the third embodiment, the reinforcing member 400C includes one third reinforcing rib 406, but the reinforcing member may include a plurality of reinforcing ribs. (12) In the above embodiment, the electrochemical reaction cell stack is a cell stack used in a solid oxide fuel cell (SOFC). However, the above configuration is also applicable to cell stacks used in other types of fuel cells, such as a polymer electrolyte fuel cell (PEFC), a phosphoric acid fuel cell (PAFC), or a molten carbonate fuel cell (MCFC), or to an electrolysis cell stack having, as a single cell, an electrolysis cell unit, which is a constituent unit of a solid oxide electrolysis cell (SOEC). [Explanation of symbols]

[0102] 10: Fuel cell stack (electrochemical reaction cell stack) 100: Power generation block 100U: Electrochemical reaction unit 110: Single cell 112: Electrolyte layer 114: Air electrode 116: Anode 118: Reaction prevention layer 120: Single cell separator 121: Through hole 124: Sealing material 130: Air electrode frame 131: Through hole 140: Anode frame 141: Through hole 144: Anode current collecting member 145: Electrode opposing portion 146: Interconnector opposing portion 147: Connection portion 149: Spacer 180: IC separator 181: Through hole 190: Interconnector 191: Flat portion 192: Air electrode current collecting portion 193: Coating layer 196: Conductive bonding material 210: First end plate 211: Flat portion 212: Through hole 213: Outer convex portion 214: Inner convex portion 220: Insulating portion 230: End separator 231: Through hole 232: First plate 240: First terminal plate 241: Through hole 250: Second terminal plate 260: Second plate 270: Second end plate (end member) 271: Flat portion (base portion) 272: Through hole 273: First retaining hole 274: First retaining cylindrical portion 280: Gas passage member 281: Main body portion 282: Flange portion 283: Gas passage 284: Bolt hole 291: Outer reinforcing wall (reinforcing wall) 292: First outer reinforcing wall (first reinforcing wall) 292E: Leading edge 293: Second outer reinforcing wall (second reinforcing wall) 293E: Leading edge 294: First reinforcing rib 296: Inner reinforcing wall (reinforcing wall) 297: First inner reinforcing wall (first reinforcing wall) 297E: Leading edge 298: Second inner reinforcing wall 299: Second reinforcing rib 311: Oxidant gas supply manifold (gas flow path) 312: Oxidant gas discharge manifold (gas flow path) 313: Air chamber (gas flow path) 321: Fuel gas supply manifold (gas flow path) 322: Fuel gas discharge manifold (gas flow path) 323: Fuel chamber (gas flow path) 400, 400B, 400C, 400D: Reinforcing member 401, 401D: Holding portion 402: Holding portion main body 403: Extension portion 404: Second holding hole 405: Second holding tube portion 406: Third reinforcing rib (reinforcing rib) 407: Jig insertion hole 501, 501B, 501D: First outer joint (first joint) 501P: Welding point 502: First inner joint (first joint)503, 503D: Second joint B: Bolt BH: Bolt hole FG: Fuel gas FOG: Fuel off-gas L1, L1B, L1D: First outer imaginary line (first imaginary line) L2: First inner imaginary line (first imaginary line) L3, L3D: Second imaginary line N: Nut OG: Oxidizer gas OOG: Oxidizer off-gas T0: End plate thickness T1, T1B, T1D, T2, T3, T3D: Joint length

Claims

1. a reaction block including a unit cell including an air electrode, an electrolyte layer, and a fuel electrode, the unit cell having a gas flow path for supplying gas around the unit cell; an end member disposed on the outside of the reaction block; a gas passage member having a gas passage communicating with the gas flow path and connected to the end member; a reinforcing member having a holding portion for holding the gas passage member; one or more joints joining the end member and the reinforcing member; Equipped with At least one of the joints has a length greater than a thickness of the end member. Electrochemical reaction cell stack.

2. the joint portion includes a first joint portion and a second joint portion different from the first joint portion, When viewed from the arrangement direction of the end member and the reaction block, a first imaginary line extending along the length direction of the first joint portion intersects with a second imaginary line extending along the length direction of the second joint portion. The electrochemical reaction cell stack according to claim 1 .

3. The length of the first joint portion and the length of the second joint portion are greater than the thickness of the end member. The electrochemical reaction cell stack according to claim 2 .

4. The end member is a base portion disposed along the reaction block and connected to the gas passage member; a reinforcing wall rising from the base to the opposite side of the reaction block; Equipped with the reinforcing wall includes a first reinforcing wall and a second reinforcing wall disposed in a different direction from the first reinforcing wall, the first joint portion is a joint portion between the first reinforcing wall and the reinforcing member, The second joint portion is a joint portion between the second reinforcing wall and the reinforcing member. The electrochemical reaction cell stack according to claim 2 .

5. At least one of the joints is formed by a plurality of weld points. The electrochemical reaction cell stack according to claim 1 or 2.

6. The end member is a base portion disposed along the reaction block and connected to the gas passage member; a reinforcing wall protruding from the base toward the opposite side to the reaction block; Equipped with At least one of the joints is disposed at a leading edge of the reinforcing wall. The electrochemical reaction cell stack according to claim 1 or 2.

7. The reinforcing member includes a reinforcing rib protruding from the holding portion. The electrochemical reaction cell stack according to claim 1 or 2.

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