Electrochemical Reaction Module

Abstract

To suppress occurrence of defects caused by a target element being contained in gas discharged from a discharge manifold, in a post-stage device to which the gas is supplied.SOLUTION: An electrochemical reaction module includes: a plurality of unit cells each including an electrolyte layer comprising a solid oxide and an air electrode and a fuel electrode facing each other with the electrolyte layer sandwiched therebetween; at least one manifold defining member; and a passage defining member. The at least one manifold defining member includes a manifold defining member with a first surface that defines a discharge manifold where gas flows, the gas passing through each cell-side gas passage facing a specific electrode which is one of the air electrode and the fuel electrode of each unit cell. The passage defining member contains a target element that is at least one of Mn and Fe, and has a surface defining an upstream gas passage located upstream of the discharge manifold. A specific compound including a specific element forming a compound with the target element exists on the first surface of the manifold defining member.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The technology disclosed herein relates to an electrochemical reaction module. [Background technology]

[0002] Solid oxide fuel cells (hereinafter referred to as "SOFCs") are known as one type of fuel cell that generates electricity using an electrochemical reaction between hydrogen and oxygen. SOFCs are generally used in the form of a fuel cell module that includes a fuel cell stack in which multiple unit cells are arranged in a predetermined direction.

[0003] The fuel cell stack is provided with an exhaust manifold for exhausting gas. More specifically, the fuel cell stack is provided with at least one of an oxidant gas exhaust manifold through which gas that has passed through a cell-side gas flow passage facing the air electrode of each unit cell flows, and a fuel gas exhaust manifold through which gas that has passed through a cell-side gas flow passage facing the fuel electrode of each unit cell flows (see, for example, Patent Document 1). The gas exhausted from the exhaust manifold may be supplied to a downstream device (for example, a combustor, another fuel cell stack, or the fuel cell stack in which the exhaust manifold is formed).

[0004] The fuel cell module also has an upstream gas flow passage formed therein, the upstream gas flow passage being located upstream of the exhaust manifold. At least a portion of the upstream gas flow passage is defined by a surface of a flow passage defining member. The flow passage defining member may be formed of a material containing at least one of a target element selected from the group consisting of Mn and Fe. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-22560 Summary of the Invention [Problem to be solved by the invention]

[0006] In a configuration in which the flow path defining member is made of a material containing the above-mentioned target element (Mn and / or Fe), when the fuel cell module becomes hot (e.g., 600°C or higher) during operation, the target element contained in the flow path defining member is dispersed into the gas flowing through the upstream gas flow path. The gas flowing through the upstream gas flow path is discharged from the fuel cell stack via an exhaust manifold and then supplied to the above-mentioned subsequent stage device. As a result, the target element is contained in the gas supplied to the subsequent stage device, and there is a risk of malfunction (e.g., clogging of the combustion nozzle in the combustor, cracks in the electrolyte layer in other fuel cell stacks or in the fuel cell stack itself) due to the target element precipitating in the subsequent stage device as an oxide (e.g., Mn3O4 or Fe2O3).

[0007] These issues are also common to electrolysis cell modules that include an electrolysis cell stack in which multiple electrolysis unit cells, which are constituent units of solid oxide electrolysis cells (hereinafter referred to as "SOEC") that generate hydrogen using the electrolysis reaction of water, are arranged. In this specification, the single fuel cell cell and the single electrolysis cell are collectively referred to as the single electrochemical reaction cell, the fuel cell stack and the electrolysis cell stack are collectively referred to as the electrochemical reaction cell stack, and the fuel cell module and the electrolysis cell module are collectively referred to as the electrochemical reaction module.

[0008] This specification discloses a technique that can solve the above-mentioned problems. [Means for solving the problem]

[0009] The technology disclosed in this specification can be realized, for example, in the following forms.

[0010] (1) The electrochemical reaction module disclosed in the present specification includes a plurality of electrochemical reaction single cells, at least one manifold defining member, and a flow path defining member. Each of the electrochemical reaction single cells includes an electrolyte layer made of a solid oxide, and an air electrode and a fuel electrode that face each other with the electrolyte layer in between, and are arranged in a predetermined direction. At least one manifold defining member includes a manifold defining member having a first surface that defines an exhaust manifold through which gas flows that has passed through each cell-side gas flow path facing a specific electrode that is one of the air electrode and the fuel electrode of each of the electrochemical reaction single cells. The flow path defining member contains a target element that is at least one of Mn and Fe, and has a surface that defines an upstream gas flow path located upstream of the exhaust manifold. A specific compound containing a specific element that forms a compound with the target element is present on the first surface of the manifold defining member.

[0011] In this electrochemical reaction module, a specific compound containing a specific element that forms a compound with a target element, which is at least one of Mn and Fe, is present on the first surface of a manifold defining member having a first surface that defines an exhaust manifold. Therefore, even if the target element contained in the flow path defining member is scattered into the upstream gas flow path when the electrochemical reaction module is heated to a high temperature during operation, etc., the target element can be captured by the specific element contained in the specific compound in the exhaust manifold located downstream of the upstream gas flow path. Therefore, in a downstream device to which the gas exhausted from the exhaust manifold is supplied, the occurrence of a malfunction caused by the target element being contained in the gas can be suppressed.

[0012] (2) In the electrochemical reaction module, the manifold defining member having the first surface may have a metal part and a coating layer covering the surface of the metal part, and the specific compound may be discretely formed on the surface of the coating layer, which is the first surface. By adopting this configuration, it is possible to disperse stress caused by volume expansion and contraction during a reaction in which a target element is captured by a specific element contained in the specific compound, and as a result, it is possible to suppress the occurrence of cracks in the coating layer.

[0013] (3) In the electrochemical reaction module, the metal part may contain the specific element. By adopting this configuration, the specific element can be continuously supplied from the metal part to the surface of the coating layer in the manifold defining member, and the function of capturing the target element by the specific compound present on the surface of the coating layer can be continuously maintained.

[0014] (4) In the electrochemical reaction module, the content of the specific element in the surface of the coating layer may be greater than the content of the specific element in the metal part. By adopting this configuration, the specific element can effectively capture the target element on the surface of the coating layer.

[0015] (5) In the electrochemical reaction module, the at least one manifold defining member may include a manifold defining member having a second surface defining a supply manifold for supplying gas to the cell-side gas flow path of each of the electrochemical reaction single cells, and the specific compound may be present on the second surface of the manifold defining member. By adopting this configuration, the target element in the gas supplied to the cell-side gas flow path of each electrochemical reaction single cell through the supply manifold can be captured by the specific compound present on the second surface, and the occurrence of defects (e.g., cracks in the electrolyte layer) caused by the target element being scattered in the cell-side gas flow path can be suppressed.

[0016] The technology disclosed in this specification can be realized in various forms, for example, in the form of an electrochemical reaction module (fuel cell module or electrolysis cell module) or a manufacturing method thereof. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell module 10 according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a perspective view showing an external configuration of a fuel cell stack 100 according to an embodiment of the present invention. [Diagram 3] FIG. 3 is an explanatory diagram showing the XZ cross-sectional configuration of the fuel cell stack 100 taken along the line III-III in FIG. 2. [Figure 4] FIG. 4 is an explanatory diagram showing the XZ cross-sectional configuration of the fuel cell stack 100 taken along the line IV-IV in FIG. 2. [Diagram 5] FIG. 3 is an explanatory diagram showing the YZ cross-sectional configuration of the fuel cell stack 100 at the VV position in FIG. 2. [Figure 6] 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. [Figure 7] 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. [Figure 8] FIG. 1 is an explanatory diagram showing a detailed configuration of a fuel electrode side frame 140. [Figure 9] FIG. 1 is an explanatory diagram showing a detailed configuration of a fuel electrode side frame 140. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] A. Embodiment: A-1. Configuration of fuel cell module 10: 1 is an explanatory diagram showing a schematic configuration of a fuel cell module 10 in this embodiment. The fuel cell module 10 includes a fuel cell stack 100 and other devices (such as a reformer / heater 330 described below). Below, the configuration of the fuel cell stack 100 will first be described, and then the configurations of the other devices constituting the fuel cell module 10 will be described. The fuel cell module 10 is an example of an electrochemical reaction module in the claims.

[0019] A-2. Configuration of fuel cell stack 100: FIG. 2 is a perspective view showing the external configuration of the fuel cell stack 100 in this embodiment. 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. 2, and FIG. 4 is an explanatory diagram showing the XZ cross-sectional configuration of the fuel cell stack 100 at the position IV-IV in FIG. 2. FIG. 5 is an explanatory diagram showing the YZ cross-sectional configuration of the fuel cell stack 100 at the position VV in FIG. 2. Each figure shows mutually orthogonal XYZ axes for specifying directions (similarly in other figures). In this specification, for convenience, the positive direction of the Z axis is called the upward direction, and the negative direction of the Z axis is called the downward direction, but the fuel cell stack 100 may actually be installed in a direction different from these directions.

[0020] As shown in FIGS. 2 to 5, the fuel cell stack 100 includes a plurality of (seven in this embodiment) fuel cell power generating units (hereinafter simply referred to as "power generating units") 102, a lower end separator 189, and a pair of end plates 104, 106. The seven power generating units 102 are arranged side by side in a predetermined arrangement direction (vertical direction in this embodiment). One of the pair of end plates 104, 106 (hereinafter referred to as "upper end plate 104") is arranged on the upper side of a power generating block 103 composed of the seven power generating units 102, and the other of the pair of end plates 104, 106 (hereinafter referred to as "lower end plate 106") is arranged below the lower end separator 189 arranged below the power generating block 103. The pair of end plates 104, 106 are arranged to sandwich the power generating block 103 and the lower end separator 189 from above and below.

[0021] 2 and 5, holes are formed in the upper surface of each layer (upper end plate 104, each power generating unit 102, lower end separator 189) constituting fuel cell stack 100 near the four corners of the outer periphery about the Z axis direction, penetrating each layer in the vertical direction, and screw holes are formed in the upper surface of lower end plate 106 near the four corners of the outer periphery about the Z axis direction. 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 fuel cell stack 100 to form bolt holes 109 may also be referred to as bolt holes 109.

[0022] A bolt 22 is inserted into each bolt hole 109. The lower end of each bolt 22 is screwed into a threaded hole formed in the lower end plate 106, and a nut 24 is fitted onto the upper end of each bolt 22. The lower surface of the nut 24 abuts against the upper surface of the end plate 104 via an insulating sheet 26. The layers of the fuel cell stack 100 are fastened together by the bolts 22 and nuts 24 configured in this way. The insulating sheet 26 is made of, for example, a mica sheet, a ceramic fiber sheet, a ceramic powder sheet, a glass sheet, a glass ceramic composite, or the like.

[0023] 2 to 4, four holes are formed in the peripheral portion around the Z axis direction of each layer constituting the fuel cell stack 100 (each power generating unit 102, lower-end separator 189, lower end plate 106), vertically penetrating each layer, and corresponding holes formed in each layer are vertically connected to each other to form communication holes 108 extending vertically 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 communication holes 108 may also be referred to as communication holes 108.

[0024] 2 and 3, one of the communication holes 108 functions as an air electrode side supply manifold 161, which is a gas flow path through which an oxidant gas OG is introduced from outside the fuel cell stack 100 and the oxidant gas OG is supplied to an air chamber 166 (described later) of each power generating unit 102, and the other communication hole 108 functions as an air electrode side exhaust manifold 162, which is a gas flow path through which an oxidant off-gas OOG, which is a gas exhausted from the air chamber 166 of each power generating unit 102, is exhausted to the outside of the fuel cell stack 100. For example, air is used as the oxidant gas OG. The air electrode side supply manifold 161 is an example of a supply manifold in the claims, and the air electrode side exhaust manifold 162 is an example of an exhaust manifold in the claims.

[0025] 2 and 4, the other communication hole 108 functions as a fuel electrode side supply manifold 171, which is a gas flow path through which a fuel gas FG is introduced from outside the fuel cell stack 100 and the fuel gas FG is supplied to a fuel chamber 176 (described later) of each power generating unit 102, and the other communication hole 108 functions as a fuel electrode side exhaust manifold 172, which is a gas flow path through which a fuel off-gas FOG, which is a gas exhausted from the fuel chamber 176 of each power generating unit 102, is exhausted to the outside of the fuel cell stack 100. For example, hydrogen-rich gas obtained by reforming city gas is used as the fuel gas FG. The fuel electrode side supply manifold 171 is an example of a supply manifold in the claims, and the fuel electrode side exhaust manifold 172 is an example of an exhaust manifold in the claims.

[0026] In this specification, a manifold defining member refers to a member having a surface that defines at least a portion of each of the manifolds 161, 162, 171, and 172. In this embodiment, the manifold defining members are the lower end plate 106, the lower end separator 189, and each of the members that configure the power generating unit 102 (the single cell separator 120, the air electrode side frame 130, the fuel electrode side frame 140, and the interconnector separator 180, which will be described later).

[0027] The fuel cell stack 100 is provided with four gas passage members 27. Each gas passage member 27 has a hollow cylindrical main body 28 and a hollow cylindrical branch portion 29 branched from a side surface of the main body 28. A hole of the branch portion 29 communicates with a hole of the main body 28. A gas pipe (not shown) is connected to the branch portion 29 of each gas passage member 27. As shown in FIG. 3, a hole of the main body 28 of the gas passage member 27 arranged at the position of the air electrode side supply manifold 161 communicates with the air electrode side supply manifold 161, and a hole of the main body 28 of the gas passage member 27 arranged at the position of the air electrode side exhaust manifold 162 communicates with the air electrode side exhaust manifold 162. 4, holes in main body 28 of gas passage member 27 arranged at the position of fuel electrode side supply manifold 171 communicate with fuel electrode side supply manifold 171, and holes in main body 28 of gas passage member 27 arranged at the position of fuel electrode side exhaust manifold 172 communicate with fuel electrode side exhaust manifold 172. An insulating sheet 26 is interposed between each gas passage member 27 and the surface of lower end plate 106.

[0028] (Configuration of end plates 104, 106) As shown in FIG. 2 to FIG. 5, the pair of end plates 104, 106 are flat plate-shaped members with an approximately rectangular outer shape as viewed in the Z-axis direction, and are made of a conductive material such as stainless steel. Holes 32, 34 are formed near the center of the pair of end plates 104, 106, penetrating in the Z-axis direction. As viewed in the Z-axis direction, the contours of the holes 32, 34 formed in each of the pair of end plates 104, 106 include each unit cell 110, which will be described later. Therefore, the compressive force in the Z-axis direction generated by fastening with each bolt 22 and nut 24 acts mainly on the periphery of each power generating unit 102 (the portion on the outer periphery side of each unit cell 110, which will be described later). In this embodiment, the upper end plate 104 functions as a positive output terminal of the fuel cell stack 100, and the lower end plate 106 functions as a negative output terminal of the fuel cell stack 100.

[0029] (Configuration of the lower end separator 189) 3 to 5, the lower-end separator 189 is a flat member having a substantially rectangular outer shape when viewed in the Z-axis direction, and is made of, for example, metal. The peripheral portion of the lower-end separator 189 is sandwiched between the power generation block 103 and the lower end plate 106, and is joined to the lower end plate 106 by, for example, welding, and is electrically connected to the lower end plate 106.

[0030] (Configuration of generating unit 102) Figure 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 Figure 3, and Figure 7 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 Figure 4.

[0031] 6 and 7, the power generating unit 102 includes a single fuel cell (hereinafter referred to as a "single cell") 110, a single cell separator 120, a pair of interconnectors 190 constituting the uppermost and lowermost layers of the power generating unit 102, an interconnector separator 180, an air electrode side frame 130, a fuel electrode side frame 140, and a fuel electrode side current collecting portion 144. Holes constituting each of the communication holes 108 functioning as each of the manifolds 161, 162, 171, 172 and holes constituting each of the bolt holes 109 are formed in the peripheral portions around the Z axis direction of the single cell separator 120, the air electrode side frame 130, the fuel electrode side frame 140, and the interconnector separator 180.

[0032] The unit cell 110 includes an electrolyte layer 112, an air electrode 114 and an anode 116 which face each other in the Z-axis direction with the electrolyte layer 112 in between, and an intermediate layer 118 disposed between the electrolyte layer 112 and the air electrode 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, air electrode 114, intermediate layer 118) which constitute the unit cell 110. The unit cell 110 is an example of an electrochemical reaction unit cell as defined in the claims.

[0033] 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 (for example, stabilized zirconia such as 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 (for example, LSCF (lanthanum strontium cobalt iron oxide)). The fuel electrode 116 is a substantially rectangular flat-plate member having approximately 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 intermediate layer 118 is a substantially rectangular flat-plate member having approximately 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) and YSZ. The intermediate layer 118 has the function of suppressing 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 to produce a highly resistive substance (e.g., SrZrO3).

[0034] The single cell separator 120 is a frame-like member having a substantially rectangular through hole 121 formed in the center and penetrating in the vertical direction, and is made of, for example, metal. A 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 (for example, Ag brazing) arranged in the facing portion. The single cell separator 120 partitions an air chamber 166 facing the air electrode 114 and a fuel chamber 176 facing the fuel electrode 116, thereby suppressing gas leakage (cross leakage) from one electrode side to the other electrode side at the peripheral portion of the single cell 110.

[0035] The single cell separator 120 includes an inner portion 126 including a 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 plate-shaped 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.

[0036] 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 of the periphery of the through-hole of the single cell separator 120 and the surface of the single cell 110 (the electrolyte layer 112 in this embodiment). The glass seal portion 125 effectively suppresses the above-mentioned cross leak.

[0037] 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, for example, ferritic stainless steel. A conductive coating layer 194 made of, for example, a spinel type oxide is formed on at least a part of the surface of the interconnector 190 facing the air chamber 166. In addition, an oxide film 198 is formed on at least a part of the surface of the interconnector 190 facing the fuel chamber 176. The oxide film 198 is composed of, for example, an inner layer containing Cr2O3 (chromia) and an outer layer containing, for example, MnCr2O4. In the following, the interconnector 190 covered with the coating layer 194 and the oxide film 198 is simply referred to as the interconnector 190. The interconnector 190 contains at least one of Mn and Fe as a target element. The interconnector 190 has a surface that defines a part of the fuel chamber 176. The fuel chamber 176 is an upstream gas flow passage located upstream of the anode-side exhaust manifold 172. Therefore, the interconnector 190 corresponds to a flow passage defining member having a surface that defines the upstream gas flow passage.

[0038] In each power generating unit 102, the upper interconnector 190 is disposed above the single cell 110. Each air electrode side current collecting portion 134 of the upper interconnector 190 is bonded to the air electrode 114 of the single cell 110 via a conductive bonding material 196 made of, for example, a spinel type oxide, and is thereby electrically connected to the air electrode 114 of the single cell 110. In each power generating unit 102, the lower interconnector 190 is disposed below the single cell 110 and is electrically connected to the fuel electrode 116 of the single cell 110 via a fuel electrode side current collecting portion 144 described later. The interconnector 190 ensures electrical conduction between the power generating units 102 and suppresses the mixing of reaction gases between the power generating units 102. In this embodiment, when two power generating units 102 are disposed adjacent to each other, one interconnector 190 is shared by the two adjacent power generating units 102. That is, the upper interconnector 190 of a certain power generating unit 102 is made of the same material as the lower interconnector 190 of another power generating unit 102 adjacent to the upper side of that power generating unit 102. Also, since the fuel cell stack 100 includes a lower end separator 189, the power generating unit 102 located at the bottom most of the fuel cell stack 100 does not include a lower interconnector 190 (see Figures 3 to 5).

[0039] The interconnector separator 180 is a frame-like member having a substantially rectangular through hole 181 formed in the vicinity of the center penetrating in the vertical direction, and is made of, for example, metal. A portion of the interconnector separator 180 surrounding 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 plate portion 150 of the interconnector 190. Of a pair of interconnector separators 180 included in a certain power generating unit 102, the upper interconnector separator 180 partitions the air chamber 166 of the power generating unit 102 from the fuel chamber 176 of the other power generating unit 102 adjacent to the power generating unit 102 on the upper side. Furthermore, of a pair of interconnector separators 180 included in a certain power generating unit 102, the lower interconnector separator 180 separates the fuel chamber 176 of that power generating unit 102 from the air chamber 166 of the other power generating unit 102 adjacent to that power generating unit 102 on the lower side. In this manner, the interconnector separator 180 suppresses gas leakage between the power generating units 102 at the periphery of the power generating units 102. The interconnector separator 180 joined to the upper interconnector 190 of the power generating unit 102 located at the uppermost position in the fuel cell stack 100 is electrically connected to the upper end plate 104.

[0040] The separator 180 for the interconnector includes an inner portion 186 including a peripheral portion of the through hole of the separator 180 for the interconnector, 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 plate-shaped extending in a direction substantially perpendicular to the Z-axis direction. The connecting portion 188 is curved so as to protrude downward with respect to 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.

[0041] The air electrode side frame 130 is a frame-shaped member having a substantially rectangular hole 131 formed near the center penetrating in the vertical 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 interconnector separator 180, and functions as a seal member that ensures gas sealing between them (i.e., gas sealing of the air chamber 166). In addition, the air electrode side frame 130 electrically insulates a pair of interconnector separators 180 included in the power generation unit 102 (i.e., a pair of interconnectors 190). The air electrode side frame 130 is formed with an air electrode side supply communication channel 132 that connects the air electrode side supply manifold 161 and the air chamber 166, and an air electrode side discharge communication channel 133 that connects the air chamber 166 and the air electrode side discharge manifold 162. The space (gas channel) formed by combining the air chamber 166, the air electrode side supply communication channel 132, and the air electrode side discharge communication channel 133 is an example of a cell side gas channel as defined in the claims.

[0042] The fuel electrode side frame 140 is a frame-like member having a substantially rectangular hole 141 formed near the center penetrating in the vertical direction, and is made of, for example, metal. The hole 141 of the fuel electrode side frame 140 constitutes a fuel chamber 176 facing 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 interconnector separator 180. The fuel electrode side frame 140 is formed with a fuel electrode side supply communication passage 142 that communicates between the fuel electrode side supply manifold 171 and the fuel chamber 176, and a fuel electrode side discharge communication passage 143 that communicates between the fuel chamber 176 and the fuel electrode side discharge manifold 172. The space (gas flow path) formed by the fuel chamber 176, the fuel electrode side supply communication flow path 142, and the fuel electrode side discharge communication flow path 143 is an example of a cell side gas flow path in the claims.

[0043] The fuel electrode side current collecting portion 144 is disposed in the fuel chamber 176. The fuel electrode side current collecting portion 144 includes an interconnector facing portion 146, an electrode facing portion 145, and a connecting portion that connects 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. However, as described above, the power generating unit 102 located at the bottom of the fuel cell stack 100 does not include the lower interconnector 190, and therefore the interconnector facing portion 146 of the fuel electrode side current collecting portion 144 of the power generating unit 102 is in contact with the lower end separator 189. The fuel electrode side current collecting portion 144 is configured as described above, and thus electrically connects the fuel electrode 116 and the interconnector 190 (or the lower end separator 189). A spacer 149 made of, for example, mica is disposed between the electrode facing portion 145 of the fuel electrode side current collecting portion 144 and the interconnector facing portion 146. Therefore, the fuel electrode side current collecting portion 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 end separator 189) via the fuel electrode side current collecting portion 144 is maintained well.

[0044] A-3. Configuration of devices other than the fuel cell stack 100 in the fuel cell module 10: Next, the configuration of the devices other than the fuel cell stack 100 in the fuel cell module 10 will be described. As shown in FIG. 1, the fuel cell module 10 includes an auxiliary device 300 including an evaporator 310 and a reformer / heater 330, and various flow paths connecting each device. Each device (fuel cell stack 100, auxiliary device 300) is housed in a heat-insulating space 351 surrounded by a heat insulating material 350. In FIG. 1, for convenience, the heat insulating material 350 is shown to have a simple rectangular shape that covers the periphery of all the devices, but in reality, it covers the periphery of all the devices and also covers the periphery of each device. In FIG. 1, the flow of gas (including raw fuel gas RFG, fuel gas FG, and fuel off-gas FOG) on the fuel electrode side is indicated by a dashed line, the flow of gas (including oxidant gas OG and oxidant off-gas OOG) on the air electrode side is indicated by a solid line, the flow of exhaust gas EG is indicated by a dashed line, and the flow of water is indicated by a two-dot chain line.

[0045] The evaporator 310 is a box-shaped member with a space formed therein, and is made of, for example, metal. The evaporator 310 is a device for evaporating water WA to generate water vapor. A pure water introduction flow path 251 for introducing the water WA is connected to the evaporator 310. The pure water introduction flow path 251 is mainly composed of piping, and an ion exchange resin, a purified water tank / float, and a flow control mechanism (not shown) are provided on the pure water introduction flow path 251. The water WA supplied from a water supply source to the pure water introduction flow path 251 has calcium ions and the like removed by the ion exchange resin, is purified and stored in the purified water tank / float, and is introduced into the evaporator 310 as pure water at a flow rate controlled by the flow control mechanism.

[0046] A raw fuel gas introduction passage 261 for introducing the raw fuel gas RFG is connected to the evaporator 310. The raw fuel gas introduction passage 261 is mainly composed of piping, and a flow control mechanism and a hydrodesulfurizer, neither of which are shown, are provided on the raw fuel gas introduction passage 261. The raw fuel gas RFG supplied from a gas source to the raw fuel gas introduction passage 261 is introduced into the evaporator 310 at a flow rate controlled by the flow control mechanism, with sulfur components removed in the hydrodesulfurizer.

[0047] Also connected to the evaporator 310 are an exhaust gas relay passage 226 for sending the exhaust gas EG from a housing 335 (described later) of the reformer / heater 330 to the evaporator 310, a mixed gas passage 228 for sending the mixed gas from the evaporator 310 to a reformer 331 (described later) of the reformer / heater 330, and an exhaust gas discharge passage (not shown) for discharging the exhaust gas EG from the evaporator 310. These passages are mainly constituted by piping.

[0048] The reformer / heater 330 includes a reformer 331, a combustor 333, and a housing 335. The housing 335 is a sealed container made of, for example, metal, and houses the reformer 331 and the combustor 333. The housing 335 has a double-wall structure having an inner wall 336 and an outer wall 337, and a heat transfer fin 339 is disposed in an air passage 338 formed between the inner wall 336 and the outer wall 337. Note that a part of the heat transfer fin 339 is not shown in FIG. 1. An air introduction passage 271 for introducing an oxidizing gas OG (air) is connected to the housing 335. The air introduction passage 271 is mainly made of piping, and a flow rate control mechanism (not shown) is provided on the air introduction passage 271. The oxidizing gas OG supplied to the air introduction passage 271 is introduced into the air passage 338 of the housing 335 at a flow rate controlled by the flow rate control mechanism. In addition, an air electrode side gas supply passage 61 for sending out an oxidant gas OG toward an air electrode side supply manifold 161 of the fuel cell stack 100 is connected to the housing 335. The air electrode side gas supply passage 61 is mainly composed of piping.

[0049] The reformer 331 is a box-shaped member with a space formed therein, and is made of, for example, metal. The reformer 331 is a device for reforming (steam reforming) the raw fuel gas RFG to generate the fuel gas FG. A catalyst for promoting the reforming reaction is disposed inside the reformer 331. As described above, the mixed gas flow path 228 for sending the mixed gas from the evaporator 310 to the reformer 331 is connected to the reformer 331. In addition, the fuel electrode side gas supply flow path 71 for sending the fuel gas FG toward the fuel electrode side supply manifold 171 of the fuel cell stack 100 is connected to the reformer 331. The fuel electrode side gas supply flow path 71 is mainly composed of piping.

[0050] The combustor 333 is a box-shaped member with a space formed therein, and is made of, for example, metal. The combustor 333 is a device for combusting the oxidant off-gas OOG and the fuel off-gas FOG. A catalyst for promoting the combustion of the oxidant off-gas OOG and the fuel off-gas FOG may be disposed in the combustor 333. The combustor 333 is connected to an air electrode side gas discharge flow path 240 through which the oxidant off-gas OOG is sent out from the air electrode side discharge manifold 162 of the fuel cell stack 100, and a fuel electrode side gas discharge flow path 230 through which the fuel off-gas FOG is sent out from the fuel electrode side discharge manifold 172 of the fuel cell stack 100. These flow paths are mainly constituted by piping.

[0051] A-4. Operation of the fuel cell module 10: Next, the operation of the fuel cell module 10 will be described. As shown in FIG. 1, the oxidant gas OG is introduced into the air flow path 338 formed in the housing 335 of the reformer / heater 330 through the air introduction flow path 271. The oxidant gas OG introduced into the air flow path 338 flows through the air flow path 338 while being heated by the combustion heat generated by the combustor 333, and is supplied to the air electrode side supply manifold 161 of the fuel cell stack 100 through the air electrode side gas supply flow path 61 in an increased temperature state. As shown in FIG. 3 and FIG. 6, the oxidant gas OG supplied to the air electrode side supply manifold 161 is supplied to the air chamber 166 through the air electrode side supply communication flow path 132 of each power generation unit 102.

[0052] As shown in FIG. 1, when raw fuel gas RFG is supplied to the evaporator 310 through the raw fuel gas introduction passage 261 and water WA is supplied to the evaporator 310 through the pure water introduction passage 251, the water WA is evaporated in the evaporator 310 using the heat of the exhaust gas EG introduced through the exhaust gas relay passage 226 to generate water vapor, and the water vapor is mixed with the raw fuel gas RFG. The raw fuel gas RFG mixed with the water vapor is introduced from the evaporator 310 through the mixed gas passage 228 to the reformer 331, where it is steam reformed, and as a result, hydrogen-rich fuel gas FG is generated. The generated fuel gas FG is supplied to the fuel electrode side supply manifold 171 of the fuel cell stack 100 through the fuel electrode side gas supply passage 71. As shown in FIG. 4 and FIG. 7, the fuel gas FG supplied to the fuel electrode side supply manifold 171 is supplied to the fuel chamber 176 through the fuel electrode side supply communication passage 142 of each power generation unit 102.

[0053] 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 of each power generating unit 102 by an electrochemical reaction between oxygen contained in the oxidant gas OG and hydrogen contained in 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 one of the interconnectors 190, and the fuel electrode 116 is electrically connected to the other of the interconnectors 190 via the fuel electrode side current collector 144. In addition, the multiple power generating units 102 included in the fuel cell stack 100 are electrically connected in series. Therefore, the electric energy generated in each power generating unit 102 is taken out from the end plates 104, 106 that function as the output terminals of the fuel cell stack 100. Note that the SOFC generates power at a relatively high temperature (for example, 700°C to 1000°C).

[0054] As shown in Figures 1, 3 and 6, the oxidant off-gas OOG discharged from the air chamber 166 of each power generating unit 102 to the air electrode side exhaust manifold 162 via the air electrode side exhaust communication passage 133 is introduced from the fuel cell stack 100 to the combustor 333 via the air electrode side gas exhaust passage 240. Also, as shown in Figures 1, 4 and 7, the fuel off-gas FOG discharged from the fuel chamber 176 of each power generating unit 102 to the fuel electrode side exhaust manifold 172 via the fuel electrode side exhaust communication passage 143 is introduced from the fuel cell stack 100 to the combustor 333 via the fuel electrode side gas exhaust passage 230. The oxidant off-gas OOG and the fuel off-gas FOG introduced into the combustor 333 are mixed and combusted in the combustor 333, and then discharged as exhaust gas EG to the evaporator 310 via the exhaust gas relay passage 226. The heat generated in the combustor 333 promotes the reforming reaction in the reformer 331 and heats the fuel cell stack 100.

[0055] A-5. Detailed configuration of the fuel electrode side frame 140: Figures 8 and 9 are explanatory diagrams showing a detailed configuration of the fuel electrode side frame 140. Figure 8 shows an enlarged view of the configuration of part X1 in Figure 7, and Figure 9 shows an enlarged view of the configuration of part X2 in Figure 7.

[0056] As described above, the fuel electrode side frame 140 is a manifold defining member having a surface that defines at least a portion of the manifold. More specifically, as shown in Fig. 8, the fuel electrode side frame 140 has a first surface 41 that defines a fuel electrode side exhaust manifold 172 that exhausts fuel off-gas FOG. Also, as shown in Fig. 9, the fuel electrode side frame 140 has a second surface 42 that defines a fuel electrode side supply manifold 171 that supplies fuel gas FG.

[0057] As shown in FIG. 8 and FIG. 9, the fuel electrode side frame 140 has a metal part 140a and a coating layer 140b that covers the surface of the metal part 140a. The metal part 140a is made of, for example, ferritic stainless steel. The coating layer 140b includes an inner layer 140c and an outer layer 140d that covers the outside of the inner layer 140c. The first surface 41 and the second surface 42 described above are the surfaces of the coating layer 140b (outer layer 140d). The inner layer 140c is made of, for example, Cr2O3 (chromia), and the outer layer 140d is made of, for example, Al2O3 (alumina). By making the outer layer 140d of alumina, it is possible to effectively prevent Cr contained in the metal part 140a from scattering into the manifold.

[0058] As shown in FIG. 8, the specific compound 43 is present on the first surface 41 that defines the fuel electrode side exhaust manifold 172 in the fuel electrode side frame 140. The specific compound 43 is a compound containing a specific element that forms a compound with the above-mentioned target element (at least one of Mn and Fe). The specific element is, for example, Ti, S, etc., and the specific compound is, for example, TiO2 (titania), Al2(SO4)3 (aluminum sulfate), etc. As shown in FIG. 8, the specific compound 43 is formed discretely (in islands) on the first surface 41 of the fuel electrode side frame 140. Since the specific compound 43 contains a specific element that forms a compound with the target element, when the target element (for example, Mn) is contained in the fuel off-gas FOG flowing through the fuel electrode side exhaust manifold 172, the target element is captured by the specific compound 43 present on the first surface 41.

[0059] 9, the specific compound 43 is also present on the second surface 42 that defines the fuel electrode side supply manifold 171 in the fuel electrode side frame 140. The specific compound 43 is formed discretely (in islands) on the second surface 42 of the fuel electrode side frame 140. When a target element (e.g., Mn) is contained in the fuel gas FG flowing through the fuel electrode side supply manifold 171, the target element is captured by the specific compound 43 present on the second surface 42.

[0060] In this embodiment, the metal part 140a of the fuel electrode side frame 140 contains the specific element. However, the content ratio of the specific element in the surface of the coating layer 140b of the fuel electrode side frame 140 is larger than the content ratio of the specific element in the metal part 140a. The content ratio of the specific element in the coating layer surface is the average value of the content ratio of the specific element at 10 points when 10 points are analyzed by point analysis in a field of view in which the coating layer surface is enlarged by 1000 times or less (for example, 1000 times) using EDS (energy dispersive X-ray spectroscopy). Specifically, the content ratio of the specific element can be determined by taking the sum of the mass concentrations of inorganic elements excluding oxygen detected by point analysis as 100%. The content ratio of the specific element in the metal part is the average value of the content ratio of the specific element at 10 points when 10 points are analyzed by point analysis in a field of view in which the cross section of the metal part is enlarged by 1000 times or less (for example, 1000 times) using EDS. The content of the specific element is determined in the same manner as the content of the specific element on the surface of the coating layer.

[0061] The fuel electrode side frame 140 having such a configuration can be manufactured by, for example, performing a heat treatment (for example, 1000°C in air for 10 hours) on a base material of ferritic stainless steel containing Al, Cr, and a specific element at a predetermined concentration. That is, by such a heat treatment, an inner layer 140c and an outer layer 140d are formed on the metal part 140a, and further, the specific element is precipitated as an oxide from the grain boundaries of the particles constituting the outer layer 140d, and an island-like specific compound 43 is formed on the surface of the outer layer 140d. However, other methods (for example, a method of applying and attaching the specific compound 43 to the surface of the fuel electrode side frame 140, etc.) may be adopted as a manufacturing method for the fuel electrode side frame 140.

[0062] A-6. Example: A sample fuel cell stack 100 was fabricated. At this time, titania was disposed as the specific compound 43 on the surface defining the manifold in the fuel electrode side frame 140. A durability test was conducted on this fuel cell stack 100 at 850°C for 2000 hours. The fuel utilization rate was 82%, and the current density was 0.47 A / cm.2 After the durability test, the fuel cell stack 100 was disassembled, and EDS mapping was performed on the surface defining the manifold in the fuel electrode side frame 140. It was found that the mapping positions of Mn and Ti overlapped. This confirmed that the specific compound 43 could capture Mn, which is a target element in the gas flowing through the manifold.

[0063] In addition, a similar durability test was performed using another sample of the fuel cell stack 100, and EDS mapping of the surface defining the manifold in the fuel electrode side frame 140 was performed. As a result, the mapping positions of Fe and Ti overlapped. Therefore, it was confirmed that the specific compound 43 can capture Fe, which is a target element in the gas flowing through the manifold.

[0064] A-7. Advantages of this embodiment: As described above, the fuel cell module 10 of this embodiment includes a plurality of unit cells 110 arranged in a predetermined direction, an anode side frame 140 serving as a manifold defining member, and an interconnector 190 serving as a flow path defining member. Each unit cell 110 includes an electrolyte layer 112 made of a solid oxide, and an air electrode 114 and an anode 116 facing each other with the electrolyte layer 112 interposed therebetween. The anode side frame 140 has a first surface 41 that defines an anode side exhaust manifold 172 through which gas flows that has passed through the cell side gas flow paths (fuel chamber 176, anode side supply communication flow path 142, and anode side exhaust communication flow path 143) facing the anode 116 of each unit cell 110. The interconnector 190 contains at least one of the target elements Mn and Fe, and has a surface that defines an upstream gas flow path (fuel chamber 176) located upstream of the anode side exhaust manifold 172. A specific compound 43 containing a specific element that forms a compound with a target element is present on a first surface 41 that defines an exhaust manifold 172 on the fuel electrode side of the frame 140 on the fuel electrode side.

[0065] Thus, in this embodiment, the specific compound 43 containing a specific element that forms a compound with a target element, which is at least one of Mn and Fe, is present on the first surface 41 of the fuel electrode side frame 140 having the first surface 41 that defines the fuel electrode side exhaust manifold 172 through which the gas that has passed through the cell side gas flow passage facing the fuel electrode 116 of each unit cell 110 flows. Therefore, even if the target element contained in the interconnector 190 is scattered into the upstream gas flow passage (fuel chamber 176) when the fuel cell module 10 is heated to a high temperature during operation, etc., the target element can be captured by the specific element contained in the specific compound in the fuel electrode side exhaust manifold 172 located downstream of the upstream gas flow passage. Therefore, in a downstream device (e.g., combustor 333) to which the gas exhausted from the fuel electrode side exhaust manifold 172 is supplied, the occurrence of a malfunction (e.g., clogging of the combustion nozzle in the combustor 333) caused by the target element being contained in the gas can be suppressed.

[0066] In this embodiment, the fuel electrode side frame 140 having the first surface 41 has a metal part 140a and a coating layer 140b covering the surface of the metal part 140a, and the specific compound 43 is formed discretely on the surface of the coating layer 140b which is the first surface 41. Therefore, it is possible to disperse stress caused by volume expansion and contraction during a reaction in which the target element is captured by the specific element contained in the specific compound 43, and as a result, it is possible to suppress the occurrence of cracks in the coating layer 140b.

[0067] In this embodiment, the metal part 140a of the fuel electrode side frame 140 contains the specific element. Therefore, in the fuel electrode side frame 140, the specific element can be continuously supplied from the metal part 140a to the surface of the coating layer 140b, and the function of capturing the target element by the specific compound 43 present on the surface of the coating layer 140b can be continuously maintained.

[0068] In this embodiment, the content ratio of the specific element on the surface of the coating layer 140b of the fuel electrode side frame 140 is higher than the content ratio of the specific element in the metal part 140a. Therefore, the target element can be effectively captured by the specific element on the surface of the coating layer 140b.

[0069] Moreover, in this embodiment, the fuel electrode side frame 140 has a second surface 42 that defines a fuel electrode side supply manifold 171 that supplies gas to the cell side gas flow path of each unit cell 110, and the specific compound 43 is also present on the second surface 42. Therefore, the target element in the fuel gas FG supplied to the cell side gas flow path of each unit cell 110 through the fuel electrode side supply manifold 171 can be captured by the specific compound 43 present on the second surface 42, and the occurrence of defects (e.g., cracks in the electrolyte layer 112) caused by the target element being scattered in the cell side gas flow path can be suppressed.

[0070] 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.

[0071] The configurations of the fuel cell module 10 and its components in the above embodiment are merely examples and can be modified in various ways. For example, in the above embodiment, the specific compound 43 is formed discretely on the surface that defines the manifold in the fuel electrode side frame 140, but the specific compound 43 may be formed continuously on the surface.

[0072] In the above embodiment, the fuel electrode side frame 140 has the metal part 140a and the coating layer 140b, but the fuel electrode side frame 140 may not have the coating layer 140b. In the above embodiment, the coating layer 140b of the fuel electrode side frame 140 includes the inner layer 140c and the outer layer 140d, but the coating layer 140b may have a single layer structure or a structure of three or more layers. In the above embodiment, the metal part 140a contains the specific element, but the metal part 140a may not contain the specific element. In the above embodiment, the content ratio of the specific element on the surface of the coating layer 140b is larger than the content ratio of the specific element in the metal part 140a, but this is not necessarily required.

[0073] In the above embodiment, the specific compound 43 is present on the surface that defines the manifold in the fuel electrode side frame 140, but instead of this, or in addition to this, the specific compound 43 may be present on the surface that defines the manifold in other manifold defining members (e.g., the lower end plate 106, the lower end separator 189, the single cell separator 120, the interconnector separator 180, etc.).

[0074] The specific compound 43 may be present on a surface of the manifold defining member that defines the anode-side exhaust manifold 172, but may not be present on a surface of the manifold defining member or another manifold defining member that defines the anode-side supply manifold 171. Conversely, the specific compound 43 may be present on a surface of the manifold defining member that defines the anode-side supply manifold 171, but may not be present on a surface of the manifold defining member or another manifold defining member that defines the anode-side exhaust manifold 172.

[0075] In the above embodiment, the specific compound 43 is present on the surface of the exhaust manifold and / or the supply manifold on the fuel electrode side, but instead of this, or in addition to this, the specific compound 43 may be present on the surface of the exhaust manifold and / or the supply manifold on the air electrode side. The electrode (fuel electrode 116 and / or air electrode 114) corresponding to the manifold in which the specific compound 43 is present is an example of the specific electrode in the claims.

[0076] In the above embodiment, the interconnector 190 as a flow path defining member contains the target element (Mn and / or Fe), but instead of or in addition to this, other flow path defining members (for example, the lower end plate 106, the lower end separator 189, the single cell separator 120, the interconnector separator 180, the gas passage member 27, various pipes forming the air electrode side gas supply flow path 61 and the fuel electrode side gas supply flow path 71 connected to the fuel cell stack 100, etc.) may contain the target element. In addition, the material forming the flow path defining members may be metal, ceramics, or other materials.

[0077] In the above embodiment, the SOFC 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 unit cell, 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 module including an electrolysis cell stack having a plurality of electrolysis unit cells. The configuration of the electrolysis cell is publicly known, for example, as described in JP 2016-81813 A, and will not be described in detail here, but it has a configuration similar to that of the fuel cell in the above embodiment. That is, the fuel cell module 10 in the above embodiment may be read as an electrolysis cell module, the fuel cell stack 100 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 module 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, an electrolysis reaction of water 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. In an electrolysis cell module having such a configuration, if a configuration similar to that of the above embodiment is adopted, it is possible to suppress the occurrence of malfunctions in a downstream device to which the gas discharged from the manifold is supplied, caused by the gas containing a target element.

[0078] 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 cells (or electrolysis cells) (so-called cylindrical flat plate type or cylindrical type). [Explanation of symbols]

[0079] 10: fuel cell module 22: bolt 24: nut 26: insulating sheet 27: gas passage member 28: main body 29: branching portion 32, 34: hole 41: first surface 42: second surface 43: specific compound 61: air electrode side gas supply flow path 71: fuel electrode side gas supply flow path 100: fuel cell stack 102: power generation unit 103: power generation block 104: upper end plate 106: lower end plate 108: communication hole 109: bolt hole 110: single cell 112: electrolyte layer 114: air electrode 116: fuel electrode 118: intermediate layer 120: single cell separator 121: through hole 124: joint 125: glass seal portion 126: inner portion 127: outer portion 128: connection portion 130: air electrode side frame 131: Hole 132: Air electrode side supply communication channel 133: Air electrode side exhaust communication channel 134: Air electrode side current collecting section 140: Anode side frame 140a: Metal section 140b: Coating layer 140c: Inner layer 140d: Outer layer 141: Hole 142: Anode side supply communication channel 143: Anode side exhaust communication channel 144: Anode side current collecting section 145: Electrode facing section 146: Interconnector facing section 149: Spacer 150: Flat plate section 161: Air electrode side supply manifold 162: Air electrode side exhaust manifold 166: Air chamber 171: Anode side supply manifold 172: Anode side exhaust manifold 176: Fuel chamber 180: Interconnector separator 181: Through hole 186: Inner section 187: Outer section 188: Connection portion 189: Lower end separator 190: Interconnector 194: Coating layer 196: Conductive bonding material 198: Oxide coating 226: Exhaust gas relay passage 228: Mixed gas passage 230: Fuel electrode side gas exhaust passage 240: Air electrode side gas exhaust passage 251: Pure water inlet passage 261: Raw fuel gas inlet passage 271: Air inlet passage 300: Auxiliary device 310: Evaporator 330: Reformer / heater 331: Reformer 333: Combustor 335: Housing 336: Inner wall 337: Outer wall 338: Air passage 339: Heat transfer fin 350: Heat insulation material 351: Heat insulation space

Claims

1. A plurality of electrochemical reaction unit cells each including an electrolyte layer made of a solid oxide, and an air electrode and a fuel electrode facing each other with the electrolyte layer therebetween, the cells being arranged in a predetermined direction; At least one manifold defining member including a first surface defining an exhaust manifold through which gas flows that has passed through each cell-side gas flow passage facing a specific electrode, which is one of the air electrode and the fuel electrode, of each of the electrochemical reaction single cells; a flow passage defining member including a surface defining an upstream gas flow passage located upstream of the exhaust manifold, the surface defining the upstream gas flow passage and including a target element selected from the group consisting of Mn and Fe; An electrochemical reaction module comprising: a specific compound including a specific element that forms a compound with the target element is present on the first surface of the manifold defining member; The specific element is Ti or S. Electrochemical reaction module comprising:

2. 2. The electrochemical reaction module of claim 1, The manifold defining member having the first surface comprises: Metal parts and A coating layer covering a surface of the metal part; having the specific compound is discretely formed on the surface of the coating layer which is the first surface; Electrochemical reaction module comprising:

3. 3. The electrochemical reaction module according to claim 2, The metal portion contains the specific element. Electrochemical reaction module comprising:

4. The electrochemical reaction module according to claim 2 or 3, The content ratio of the specific element in the surface of the coating layer is greater than the content ratio of the specific element in the metal portion. Electrochemical reaction module comprising:

5. The electrochemical reaction module according to any one of claims 1 to 3, the at least one manifold-defining member includes a manifold-defining member having a second surface that defines a supply manifold that supplies gas to the cell-side gas flow passage of each of the electrochemical reaction sub-cells; the specific compound is present on the second surface of the manifold defining member; Electrochemical reaction module comprising:

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