JP2021022471A - Electrochemical reaction cell stack - Google Patents

Abstract

To suppress degradation in power generation performance of a fuel cell stack resulting from deterioration of gas flow in a gas chamber caused by positional deviation of a spacer.SOLUTION: An electrochemical reaction cell stack comprises a second conductive member having a first contact part in contact with the surface of a first conductive member, a second contact part in contact with a first electrode that is one of an air electrode and a fuel electrode, and a connecting part for connecting the first and second contact parts. The second conductive member has a first tip connected with the side opposite from the side connected with the connecting part in the second contact part, and when assuming that at least one profile in parallel with the first direction is a specific profile, and a direction perpendicular to the first direction in the specific profile is a second direction, at least a part of the first tip of the second conductive member in specific reactive unit, i.e., at least one electrochemical reaction unit, is located on the opposite side to the side of the connecting part in the second direction for a spacer in the specific profile.SELECTED DRAWING: Figure 8

Description

The techniques disclosed herein relate to electrochemical reaction cell stacks.

A solid oxide fuel cell (hereinafter referred to as "SOFC") is known as one of the fuel cells that generate electricity by utilizing an electrochemical reaction between hydrogen and oxygen. The SOFC is generally used in the form of a fuel cell stack in which a plurality of fuel cell power generation units (hereinafter referred to as "power generation units") are arranged side by side in a predetermined direction (hereinafter referred to as "first direction"). .. The power generation unit includes a fuel cell single cell (hereinafter, simply referred to as “single cell”). The single cell includes an electrolyte layer and an air electrode and a fuel electrode that face each other in the first direction with the electrolyte layer in between.

The power generation unit also includes an interconnector arranged on the side in the first direction with respect to the single cell, a current collector on the fuel electrode side, and a spacer. The fuel electrode side current collector includes an interconnector contact portion that contacts the surface of the interconnector, an electrode contact portion that contacts the fuel electrode, and a connecting portion that connects the interconnector contact portion and the electrode contact portion. And the interconnector are electrically connected. The spacer is arranged between the interconnector contact portion and the electrode contact portion of the fuel electrode side current collector. By arranging a spacer between the interconnector contact part and the electrode contact part of the fuel electrode side current collector, the fuel electrode side current collector follows the deformation of the power generation unit due to the temperature cycle and the reaction gas pressure fluctuation. Good electrical connection between the fuel electrode and the interconnector via the fuel electrode side current collector is maintained.

JP-A-2018-185957

However, in the conventional fuel cell stack described above, the force for the fuel cell side current collector to sandwich the spacer cannot be secured due to factors such as the difference in thermal expansion of each part of the fuel cell stack (for example, the fuel electrode and the interconnector). Misalignment may occur in a direction perpendicular to the first direction of the spacer (more strictly, a direction opposite to the side of the connecting portion of the fuel electrode side current collector with respect to the spacer). Therefore, in the conventional fuel cell stack described above, there is a risk that the gas flow in the fuel chamber will deteriorate due to the displacement in the direction perpendicular to the first direction of the spacer, and eventually the power generation performance of the fuel cell stack will deteriorate. is there.

In addition, such a problem is an air provided with an interconnector contact portion that contacts the surface of the interconnector, an electrode contact portion that contacts the air electrode, and a connecting portion that connects the interconnector contact portion and the electrode contact portion. Even in a fuel cell stack in which a pole-side current collector is provided and a spacer is arranged between the interconnector contact portion and the electrode contact portion of the air pole-side current collector, the direction is perpendicular to the first direction of the spacer. It also occurs due to misalignment. Further, such a problem is an electrolysis having a plurality of electrolytic cell units, which are constituent units of a solid oxide fuel cell (hereinafter referred to as “SOEC”) that generates hydrogen by utilizing an electrolysis reaction of water. This is a common problem with cell stacks. In the present specification, the fuel cell single cell and the electrolytic single cell are collectively referred to as an electrochemical reaction single cell, and the power generation unit and the electrolytic cell unit are collectively referred to as an electrochemical reaction unit, and the fuel cell stack and the electrolytic cell are collectively referred to as an electrochemical reaction unit. The stack is collectively called an electrochemical reaction cell stack. Further, such a problem is common not only to SOFC and SOEC but also to other types of electrochemical reaction cell stacks.

This specification discloses a technique capable of solving the above-mentioned problems.

The technique disclosed in the present specification can be realized in the following forms.

(1) The electrochemical reaction cell stack disclosed in the present specification includes a single cell including an electrolyte layer, an air electrode and a fuel electrode facing each other in a first direction across the electrolyte layer, and the single cell. A first conductive member arranged on the side of the cell in the first direction, a first contact portion in contact with the surface of the first conductive member, and one of the air electrode and the fuel electrode. A second conductive member including a second contact portion that contacts the first electrode, and a connecting portion that connects the first contact portion and the second contact portion, and the second conductive portion. In an electrochemical reaction cell stack in which a plurality of electrochemical reaction units including a spacer arranged between the first contact portion and the second contact portion of the member are arranged side by side, the second conductive member Provided a first tip portion connected to the side opposite to the side connected to the connecting portion in the second contact portion, and at least one cross section parallel to the first direction was defined as a specific cross section. When the direction perpendicular to the first direction in the specific cross section is defined as the second direction, the second conductive member of the specific reaction unit which is at least one electrochemical reaction unit in the specific cross section. At least a part of the first tip portion is located on the side opposite to the side of the connecting portion in the second direction with respect to the spacer.

Here, in the above-mentioned electrochemical reaction cell stack, in the configuration in which the second conductive member does not include the first tip portion, each part of the above-mentioned electrochemical reaction cell stack (for example, the first electrode, the first one). Due to factors such as the difference in thermal expansion of the conductive member), the force for sandwiching the spacer by the second conductive member cannot be secured, and the spacer may be displaced in the second direction. Therefore, in this configuration, the displacement of the spacer in the second direction deteriorates the gas flow in the gas chamber (the gas chamber facing the first electrode), which in turn worsens the electrochemical reaction cell. The power generation performance of the stack may deteriorate.

On the other hand, in the present electrochemical reaction cell stack, as described above, in the specific cross section, the entire first tip portion of the second conductive member is connected to the spacer in the second direction. It is located on the opposite side of the section. Therefore, the presence of the first tip of the second conductive member suppresses the displacement of the spacer in the second direction. Therefore, according to the present electrochemical reaction cell stack, the gas flow in the gas chamber (the gas chamber facing the first electrode) is deteriorated due to the misalignment of the spacer in the second direction. It is possible to suppress the deterioration of the power generation performance of the electrochemical reaction cell stack.

(2) In the electrochemical reaction cell stack, the first tip portion of the second conductive member of the specific reaction unit may be joined to the first conductive member. According to the present electrochemical reaction cell stack, the displacement of the spacer in the second direction can be suppressed more effectively.

(3) In the electrochemical reaction cell stack, when the direction perpendicular to the specific cross section is set as the third direction, in the cross section perpendicular to the specific cross section, the second conductive member of the specific reaction unit is A second tip that is connected to at least one specific side of the third direction end of the second contact, at least part of which is the third with respect to the spacer. A configuration may be configured in which a second tip portion located on the specific one side of the direction is provided.

Here, in the above-mentioned electrochemical reaction cell stack, in the configuration in which the second conductive member does not include the second tip portion, each part of the above-mentioned electrochemical reaction cell stack (for example, the first electrode, the first one). Due to factors such as the difference in thermal expansion of the conductive member), the force for sandwiching the spacer by the second conductive member cannot be secured, and the spacer may be displaced in the third direction. Therefore, in this configuration, the gas flow in the gas chamber (the gas chamber facing the first electrode) deteriorates due to the displacement of the spacer in the third direction, which in turn deteriorates the electrochemistry. The power generation performance of the reaction cell stack may deteriorate.

On the other hand, in the present electrochemical reaction cell stack, as described above, in the cross section perpendicular to the specific cross section, the second conductive member of each electrochemical reaction unit is in the third direction at the electrode contact portion. A second tip that is connected to the end of the spacer and that is entirely located on the third direction side of the spacer. Therefore, according to the present electrochemical reaction cell stack, it is possible to suppress the misalignment of the spacer in the third direction.

(4) In the electrochemical reaction cell stack, the second conductive member of the specific reaction unit is joined to the first conductive member on the side in the third direction with respect to the spacer. May be. According to the present electrochemical reaction cell stack, the displacement of the spacer in the third direction can be suppressed.

(5) In the electrochemical reaction cell stack, the spacer of the specific reaction unit is a portion protruding to the outside of the second conductive member in the first directional view, and is said in the second directional view. It may be configured to have a portion overlapping the second conductive member. Also in the present electrochemical reaction cell stack, the displacement of the spacer in the third direction can be suppressed.

(6) In the electrochemical reaction cell stack, the position where the first tip portion of the second conductive member of the specific reaction unit is joined to the first conductive member is the position where the second conductive member is joined. The configuration may be such that the center of the first tip of the member in the second direction or the side closer to the spacer than the center. In the present electrochemical reaction cell stack, the position where the first tip of the second conductive member of the electrochemical reaction unit is joined to the first conductive member is relatively close to the spacer. Therefore, according to the present electrochemical reaction cell stack, the displacement of the spacer in the second direction can be suppressed more effectively.

(7) In the electrochemical reaction cell stack, the position where the first tip portion of the second conductive member of the specific reaction unit is joined to the first conductive member is the second conductive member. The configuration may be such that the center of the first tip portion of the member in the second direction or the side farther from the spacer than the center. In the present electrochemical reaction cell stack, the first tip portion of the first tip portion of the second conductive member is closer to the spacer than the position where the first tip portion is joined to the first conductive member. Since the side portion is not joined to the first conductive member, it can be freely extended to some extent when the space between the first electrode and the first conductive member is widened. .. Therefore, according to the present electrochemical reaction cell stack, the portion of the first tip portion of the second conductive member that is not joined to the first conductive member is relatively long. It is more effective to prevent the contact area between the first electrode and the electrode contact portion of the second conductive member from becoming smaller when the space between the electrode 1 and the first conductive member is widened. As a result, the deterioration of the power generation performance of the electrochemical reaction cell stack can be suppressed more effectively.

(8) In the electrochemical reaction cell stack, the second conductive member of the specific reaction unit is configured such that a space is formed between the connecting portion of the second conductive member and the spacer. It may be configured as such.

When the space between the first electrode and the first conductive member expands due to a difference in thermal expansion of each part of the electrochemical reaction cell stack (for example, the first electrode and the first conductive member). , The first electrode and the electrode contact portion of the second conductive member may be peeled off. As a result, the contact area between the first electrode and the electrode contact portion of the second conductive member becomes smaller, which may reduce the power generation performance of the electrochemical reaction cell stack.

On the other hand, in the present electrochemical reaction cell stack, as described above, the second conductive member is configured such that a space is formed between the connecting portion of the second conductive member and the spacer. ing. Therefore, in the electrode contact portion of the second conductive member, the portion on the side of the connecting portion and the portion of the interconnector contact portion 146 on the side of the connecting portion are all in contact with the first electrode. Therefore, when the space between the first electrode and the first conductive member is widened, it can be freely extended to some extent. Therefore, according to the present electrochemical reaction cell stack, the space between the first electrode and the first conductive member is widened so that the first electrode and the electrode contact portion of the second conductive member can be brought into contact with each other. It is possible to suppress the reduction of the contact area of the above, and thus the deterioration of the power generation performance of the electrochemical reaction cell stack.

(9) In the electrochemical reaction cell stack, the first tip portion may be in contact with the spacer. According to the present electrochemical reaction cell stack, the displacement of the spacer in the second direction can be suppressed more effectively.

The technique disclosed in the present specification can be realized in various forms, for example, an electrochemical reaction cell stack (fuel cell stack or electrolytic cell stack), an electrochemical reaction cell stack including an electrochemical reaction cell stack. It can be realized in the form of a reaction system (fuel cell system or electrolytic cell system), a method for producing them, and the like.

It is a perspective view which shows the appearance structure of the fuel cell stack 100 in embodiment. It is explanatory drawing which shows the XZ cross-sectional structure of the fuel cell stack 100 at the position of II-II of FIG. It is explanatory drawing which shows the YZ cross-sectional structure of the fuel cell stack 100 at the position of III-III of FIG. It is explanatory drawing which shows the XZ cross section configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. It is explanatory drawing which shows the YZ cross section configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. It is explanatory drawing which shows the XY cross-sectional structure of the power generation unit 102 at the position of VI-VI of FIG. It is explanatory drawing which shows the XY cross-sectional structure of the power generation unit 102 at the position of VII-VII of FIG. It is explanatory drawing which enlarges and shows the XZ cross-sectional structure of a part (X1 part of FIG. 4) of a single cell 110. It is explanatory drawing which enlarges and shows the YZ cross-sectional structure of a part (X2 part of FIG. 5) of a single cell 110. It is explanatory drawing which shows the protrusion 149A of the spacer 149 in the modification.

A. Embodiment:
A-1. Constitution:
(Structure of fuel cell stack 100)
FIG. 1 is a perspective view showing an external configuration of the fuel cell stack 100 in the present embodiment, and FIG. 2 is an explanatory view showing an XZ cross-sectional configuration of the fuel cell stack 100 at the position II-II of FIG. FIG. 3 is an explanatory view showing a YZ cross-sectional configuration of the fuel cell stack 100 at the position III-III of FIG. Each figure shows XYZ axes that are orthogonal to each other to identify the direction. In the present specification, for convenience, the Z-axis positive direction is referred to as "upward" and the Z-axis negative direction is referred to as "downward", but the fuel cell stack 100 is actually in such an orientation. It may be installed in a different orientation. The same applies to FIGS. 4 and later. The vertical direction (Z-axis direction) corresponds to the first direction in the claims. The fuel cell stack corresponds to the electrochemical reaction cell stack in the claims.

The fuel cell stack 100 includes a plurality of power generation units 102 (seven in this embodiment) and a pair of end plates 104 and 106. The seven power generation units 102 are arranged side by side in a predetermined arrangement direction (vertical direction in the present embodiment). The pair of end plates 104 and 106 are arranged so as to sandwich an aggregate composed of seven power generation units 102 from above and below.

A plurality of holes (eight in this embodiment) penetrating in the vertical direction are formed on the peripheral edge of each layer (power generation unit 102, end plates 104, 106) constituting the fuel cell stack 100 in the vertical direction. The holes formed in each layer and corresponding to each other communicate with each other in the vertical direction to form a communication hole 108 extending in the vertical direction from one end plate 104 to the other end plate 106. In the following description, the holes formed in each layer of the fuel cell stack 100 to form the communication holes 108 are also referred to as “communication holes 108”.

A bolt 22 extending in the vertical direction is inserted into each communication hole 108, and the fuel cell stack 100 is fastened by the bolt 22 and the nuts 24 fitted on both sides of the bolt 22. As shown in FIGS. 2 and 3, between the nut 24 fitted on one side (upper side) of the bolt 22 and the upper surface of the end plate 104 forming the upper end of the fuel cell stack 100, and the bolt. An insulating sheet 26 is interposed between the nut 24 fitted on the other side (lower side) of the 22 and the lower surface of the end plate 106 forming the lower end of the fuel cell stack 100. However, in the place where the gas passage member 27 described later is provided, the insulating sheets arranged on the upper side and the lower side of the gas passage member 27 and the gas passage member 27 between the nut 24 and the surface of the end plate 106, respectively. 26 is intervening. The insulating sheet 26 is made of, for example, a mica sheet, a ceramic fiber sheet, a ceramic dust sheet, a glass sheet, a glass-ceramic composite agent, or the like.

The outer diameter of the shaft portion of each bolt 22 is smaller than the inner diameter of each communication hole 108. Therefore, a space is secured between the outer peripheral surface of the shaft portion of each bolt 22 and the inner peripheral surface of each communication hole 108. As shown in FIGS. 1 and 2, near the midpoint of one side (the side on the positive side of the X-axis of the two sides parallel to the Y-axis) on the outer circumference of the fuel cell stack 100 around the Z-axis direction. In the space formed by the position bolt 22 (bolt 22A) and the communication hole 108 into which the bolt 22A is inserted, the oxidant gas OG is introduced from the outside of the fuel cell stack 100, and the oxidant gas OG is introduced into each of the spaces. It functions as an oxidizer gas supply manifold 161 which is a gas flow path for supplying to the power generation unit 102, and is inside the side opposite to the side (the side on the negative direction of the X axis among the two sides parallel to the Y axis). The space formed by the bolt 22 (bolt 22B) located near the point and the communication hole 108 into which the bolt 22B is inserted is an oxidizer off-gas OOG which is a gas discharged from the air chamber 166 of each power generation unit 102. Functions as an oxidant gas discharge manifold 162 that discharges the fuel cell stack 100 to the outside. In this embodiment, for example, air is used as the oxidant gas OG.

Further, as shown in FIGS. 1 and 3, the midpoint of one side (the side on the positive side of the Y-axis of the two sides parallel to the X-axis) on the outer circumference of the fuel cell stack 100 around the Z-axis direction. A fuel gas FG is introduced from the outside of the fuel cell stack 100 into the space formed by the bolt 22 (bolt 22D) located in the vicinity and the communication hole 108 into which the bolt 22D is inserted, and the fuel gas FG is introduced into each of the spaces. A bolt that functions as a fuel gas supply manifold 171 to supply to the power generation unit 102 and is located near the midpoint of the opposite side (the side on the negative side of the Y axis of the two sides parallel to the X axis). The space formed by the 22 (bolt 22E) and the communication hole 108 into which the bolt 22E is inserted is provided with the fuel off-gas FOG, which is the gas discharged from the fuel chamber 176 of each power generation unit 102, outside the fuel cell stack 100. It functions as a fuel gas discharge manifold 172 that discharges to. In the present embodiment, for example, a hydrogen-rich gas obtained by reforming city gas is used as the fuel gas FG.

The fuel cell stack 100 is provided with four gas passage members 27. Each gas passage member 27 has a hollow tubular main body 28 and a hollow tubular branch 29 branched from the side surface of the main body 28. The hole of the branch portion 29 communicates with the hole of the main body portion 28. A gas pipe (not shown) is connected to the branch portion 29 of each gas passage member 27. Further, as shown in FIG. 2, the hole of the main body 28 of the gas passage member 27 arranged at the position of the bolt 22A forming the oxidant gas supply manifold 161 communicates with the oxidant gas supply manifold 161. The hole of the main body 28 of the gas passage member 27 arranged at the position of the bolt 22B forming the oxidant gas discharge manifold 162 communicates with the oxidant gas discharge manifold 162. Further, as shown in FIG. 3, the hole of the main body 28 of the gas passage member 27 arranged at the position of the bolt 22D forming the fuel gas supply manifold 171 communicates with the fuel gas supply manifold 171 and fuel gas. The hole of the main body 28 of the gas passage member 27 arranged at the position of the bolt 22E forming the discharge manifold 172 communicates with the fuel gas discharge manifold 172.

(Structure of end plates 104 and 106)
The pair of end plates 104 and 106 are substantially rectangular flat plate-shaped conductive members, and are made of, for example, stainless steel. One end plate 104 is arranged above the power generation unit 102 located at the top, and the other end plate 106 is arranged below the power generation unit 102 located at the bottom. A plurality of power generation units 102 are held in a pressed state by a pair of end plates 104 and 106. 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.

(Structure of power generation unit 102)
FIG. 4 is an explanatory view showing an XZ cross-sectional configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. 2, and FIG. 5 is an explanatory view showing an XZ cross-sectional configuration at the same position as the cross section shown in FIG. It is explanatory drawing which shows the YZ cross-sectional structure of two power generation units 102. Further, FIG. 6 is an explanatory view showing an XY cross-sectional configuration of the power generation unit 102 at the position of VI-VI of FIGS. 4 and 5, and FIG. 7 is a power generation unit at the position of VII-VII of FIGS. 4 and 5. It is explanatory drawing which shows the XY cross-sectional structure of 102.

As shown in FIGS. 4 and 5, the power generation unit 102 includes a single cell 110, a separator 120, an air pole side frame 130, an air pole side current collector 134, a fuel pole side frame 140, and a fuel pole side. It includes a current collector 144, a spacer 149, and a pair of interconnectors 150 that form the uppermost layer and the lowermost layer of the power generation unit 102. Holes corresponding to the communication holes 108 through which the above-mentioned bolts 22 are inserted are formed in the peripheral portions of the separator 120, the air pole side frame 130, the fuel pole side frame 140, and the interconnector 150 in the Z direction.

The interconnector 150 is a substantially rectangular flat plate-shaped conductive member, and is made of, for example, ferritic stainless steel. The interconnector 150 ensures electrical continuity between the power generation units 102 and prevents mixing of reaction gases between the power generation units 102. In the present embodiment, when two power generation units 102 are arranged adjacent to each other, one interconnector 150 is shared by two adjacent power generation units 102. That is, the upper interconnector 150 in a certain power generation unit 102 is the same member as the lower interconnector 150 in another power generation unit 102 adjacent to the upper side of the power generation unit 102. Further, since the fuel cell stack 100 includes a pair of end plates 104 and 106, the power generation unit 102 located at the top of the fuel cell stack 100 does not have the upper interconnector 150 and is located at the bottom. The power generation unit 102 does not include the lower interconnector 150 (see FIGS. 2 and 3).

The single cell 110 includes an electrolyte layer 112, an air electrode (cathode) 114 and a fuel electrode (anode) 116 facing each other in the vertical direction (arrangement direction in which the power generation units 102 are arranged) with the electrolyte layer 112 in between. That is, the air pole 114 and the fuel pole 116 face each other in the vertical direction with the electrolyte layer 112 interposed therebetween. The single cell 110 of the present embodiment is a fuel pole support type single cell in which the fuel pole 116 supports the electrolyte layer 112 and the air pole 114.

The electrolyte layer 112 is a flat plate-shaped member that is substantially rectangular in the vertical direction, and is a dense layer (with a low porosity). The term "vertical view" as used herein means "when viewed from a direction parallel to the vertical direction" (the same applies to "vertical view" below). The electrolyte layer 112 is formed of, for example, a solid oxide such as YSZ (yttria-stabilized zirconia), ScSZ (scandia-stabilized zirconia), SDC (samarium-doped ceria), GDC (gadolinium-doped ceria), and perovskite-type oxide. There is. The air electrode 114 is a substantially rectangular flat plate-shaped member smaller than the electrolyte layer 112 in the vertical direction, and is a porous layer (having a higher porosity than the electrolyte layer 112). The air electrode 114 is formed of, for example, a perovskite-type oxide (for example, LSCF (lanternstrontium cobalt iron oxide), LSM (lanternstrontium manganese oxide), LNF (lantern nickel iron)). The fuel electrode 116 is a substantially rectangular flat plate-shaped member having substantially the same size as the electrolyte layer 112 in the vertical direction, and is a porous layer (having a higher porosity than the electrolyte layer 112). The thickness of the fuel electrode 116 is, for example, 200 μm to 1000 μm. The average porosity of the portion of the fuel electrode 116 near the current collector 144 on the fuel electrode side is, for example, 25 to 60 vol%, and the average porosity of the portion is, for example, 0.5 μm to 4 μm. The single cell 110 (power generation unit 102) of the present embodiment having such a configuration is a solid oxide fuel cell (SOFC) that uses a solid oxide as an electrolyte.

The separator 120 is a frame-shaped member in which a substantially rectangular hole 121 penetrating in the vertical direction is formed near the center, and is made of metal, for example. The peripheral portion of the hole 121 in the separator 120 faces the peripheral edge of the surface of the electrolyte layer 112 on the side of the air electrode 114. The separator 120 is bonded to the electrolyte layer 112 (single cell 110) by a bonding portion 124 formed of a brazing material (for example, Ag wax) arranged at the opposite portion thereof. The separator 120 partitions the air chamber 166 facing the air electrode 114 and the fuel chamber 176 facing the fuel electrode 116, and a gas leak from one electrode side to the other electrode side at the peripheral edge of the single cell 110. It is suppressed.

As shown in FIG. 6, the air electrode side frame 130 is a frame-shaped member in which a substantially rectangular hole 131 penetrating in the vertical direction is formed near the center, and is formed of, for example, 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 peripheral edge of the surface of the separator 120 opposite to the side facing the electrolyte layer 112 and the peripheral edge of the surface of the interconnector 150 facing the air electrode 114. .. Further, the air electrode side frame 130 electrically insulates between the pair of interconnectors 150 included in the power generation unit 102. Further, in the air electrode side frame 130, the oxidant gas supply communication hole 132 that communicates the oxidant gas supply manifold 161 and the air chamber 166, and the oxidant gas that communicates the air chamber 166 and the oxidant gas discharge manifold 162. A discharge communication hole 133 is formed.

As shown in FIG. 7, the fuel electrode side frame 140 is a frame-shaped member in which a substantially rectangular hole 141 penetrating in the vertical direction is formed near the center, and is formed of, for example, metal. 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 peripheral edge of the surface of the separator 120 facing the electrolyte layer 112 and the peripheral edge of the surface of the interconnector 150 facing the fuel electrode 116. Further, in the fuel electrode side frame 140, a fuel gas supply communication hole 142 that communicates the fuel gas supply manifold 171 and the fuel chamber 176, and a fuel gas discharge communication hole 143 that communicates the fuel chamber 176 and the fuel gas discharge manifold 172. And are formed.

The air pole side current collector 134 is arranged in the air chamber 166. The air electrode side current collector 134 is composed of a plurality of substantially square columnar current collector elements, and is formed of, for example, ferritic stainless steel. The air electrode side current collector 134 is in contact with the surface of the air electrode 114 opposite to the side facing the electrolyte layer 112 and the surface of the interconnector 150 on the side facing the air electrode 114. However, as described above, since the power generation unit 102 located at the top of the fuel cell stack 100 does not have the upper interconnector 150, the air electrode side current collector 134 in the power generation unit 102 has an upper end plate. It is in contact with 104. Since the air electrode side current collector 134 has such a configuration, the air electrode 114 and the interconnector 150 (or the end plate 104) are electrically connected. In the present embodiment, the air electrode side current collector 134 and the interconnector 150 are formed as an integral member. That is, the flat plate-shaped portion of the integral member that is orthogonal to the vertical direction (Z-axis direction) functions as the interconnector 150, and is formed so as to project from the flat plate-shaped portion toward the air electrode 114. The current collector elements, which are a plurality of convex portions, function as the air electrode side current collector 134. Further, the integral member of the air electrode side current collector 134 and the interconnector 150 may be covered with a conductive coat, and both are placed between the air electrode 114 and the air electrode side current collector 134. A conductive bonding layer to be bonded may be interposed.

The fuel electrode side current collector 144 is arranged in the fuel chamber 176. The fuel electrode side current collector 144 is a connecting portion 147 that connects the interconnector contact portion 146, the electrode contact portion 145, the X-axis positive direction side of the electrode contact portion 145, and the X-axis positive direction side of the interconnector contact portion 146. A first tip portion 148 and a second tip portion 148A are provided, and are formed of, for example, nickel, a nickel alloy, stainless steel, or the like. The electrode contact portion 145 is in contact with the surface of the fuel electrode 116 on the side opposite to the side facing the electrolyte layer 112. The interconnector contact portion 146 is in contact with the surface of the interconnector 150 on the side facing the fuel electrode 116. That is, the interconnector contact portion 146 is provided on the surface of the interconnector 150 arranged on the lower side (one in the vertical direction) of the single cell 110 among the pair of interconnectors 150 provided in the power generation unit 102. Are in contact. In the present embodiment, of the pair of interconnectors 150 provided in the power generation unit 102, the lower interconnector 150 corresponds to the first conductive member within the scope of the claims. However, as described above, since the power generation unit 102 located at the bottom of the fuel cell stack 100 does not have the lower interconnector 150, the interconnector contact portion 146 in the power generation unit 102 is the lower end plate. It is in contact with 106. As shown in FIG. 4, the first tip portion 148 is connected to the side opposite to the side connected to the connecting portion 147 in the electrode contact portion 145 (X-axis negative direction side). As shown in FIG. 5, the second tip portion 148A is connected to one end (Y-axis negative direction) and the other (Y-axis positive direction) end of the electrode contact portion 145 in the Y-axis direction. There is. The detailed configuration of the first tip portion 148 and the second tip portion 148A will be described later. The fuel electrode side current collector 144 corresponds to the second conductive member in the claims. The interconnector contact portion 146 corresponds to the first contact portion in the claims. The electrode contact portion 145 corresponds to the second contact portion in the claims. In the present embodiment, the Y-axis direction corresponds to the third direction in the claims.

In the present embodiment, the fuel electrode side current collector 144 is formed of, for example, a metal foil (for example, a thickness of 10 to 800 μm) formed of nickel, a nickel alloy, stainless steel, or the like. As shown in the partially enlarged view in FIG. 7, the fuel electrode side current collector 144 is manufactured by making a notch in a substantially rectangular metal leaf and processing the plurality of rectangular portions so as to bend them up.

Since the fuel pole side current collector 144 has such a configuration, the fuel pole 116 and the interconnector 150 (or the end plate 106) are electrically connected to each other. In the present embodiment, the interconnector contact portion 146 of the fuel electrode side current collector 144, the electrode contact portion 145, the connecting portion 147, the first tip portion 148, and the second tip portion 148A are configured by an integral member. Has been done.

A spacer 149 formed of, for example, mica is arranged between the electrode contact portion 145 and the interconnector contact portion 146. Therefore, the fuel electrode side current collector 144 follows the deformation of the power generation unit 102 due to the temperature cycle and the reaction gas pressure fluctuation, and the fuel electrode 116 and the interconnector 150 (or the end plate 106) via the fuel electrode side current collector 144 follow. Good electrical connection with is maintained. The plate thickness of the spacer 149 is, for example, 0.5 to 3 mm.

A-2. Operation of fuel cell stack 100:
As shown in FIGS. 2, 4 and 6, the oxidant gas is passed through a gas pipe (not shown) connected to the branch portion 29 of the gas passage member 27 provided at the position of the oxidant gas supply manifold 161. When the OG is supplied, the oxidant gas OG is supplied to the oxidant gas supply manifold 161 through the holes of the branch portion 29 and the main body portion 28 of the gas passage member 27, and each power generation unit is supplied from the oxidant gas supply manifold 161. It is supplied to the air chamber 166 through the oxidant gas supply communication hole 132 of 102. Further, as shown in FIGS. 3, 5 and 7, fuel gas is passed through a gas pipe (not shown) connected to a branch portion 29 of the gas passage member 27 provided at the position of the fuel gas supply manifold 171. When the FG is supplied, the fuel gas FG is supplied to the fuel gas supply manifold 171 through the holes of the branch portion 29 and the main body portion 28 of the gas passage member 27, and the fuel of each power generation unit 102 is supplied from the fuel gas supply manifold 171. It is supplied to the fuel chamber 176 via the gas supply communication hole 142.

When the oxidant gas OG is supplied to the air chamber 166 of each power generation unit 102 and the fuel gas FG is supplied to the fuel chamber 176, oxygen contained in the oxidant gas OG and hydrogen contained in the fuel gas FG in the single cell 110 are supplied. Power is generated by the electrochemical reaction with. This power generation reaction is an exothermic reaction. In each power generation unit 102, the air pole 114 of the single cell 110 is electrically connected to one of the interconnectors 150 via the air pole side current collector 134, and the fuel pole 116 is via the fuel pole side current collector 144. It is electrically connected to the other interconnector 150. Further, the plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. Therefore, the electric energy generated in each power generation unit 102 is taken out from the end plates 104 and 106 that function as the output terminals of the fuel cell stack 100. Since the SOFC generates electricity at a relatively high temperature (for example, 700 ° C. to 1000 ° C.), the fuel cell stack 100 is a heater (for example, until the high temperature can be maintained by the heat generated by the power generation after the start-up. (Not shown) may be heated.

The oxidant off-gas OOG discharged from the air chamber 166 of each power generation unit 102 is discharged to the oxidant gas discharge manifold 162 through the oxidant gas discharge communication hole 133 as shown in FIGS. 2, 4 and 6. Further, the fuel is passed through the holes of the main body 28 and the branch 29 of the gas passage member 27 provided at the position of the oxidant gas discharge manifold 162, and through the gas pipe (not shown) connected to the branch 29. It is discharged to the outside of the battery stack 100. Further, the fuel off-gas FOG discharged from the fuel chamber 176 of each power generation unit 102 is discharged to the fuel gas discharge manifold 172 through the fuel gas discharge communication hole 143 as shown in FIGS. 3, 5 and 7. Further, the fuel cell stack 100 is passed through the holes of the main body 28 and the branch 29 of the gas passage member 27 provided at the position of the fuel gas discharge manifold 172, and through a gas pipe (not shown) connected to the branch 29. It is discharged to the outside of.

A-3. Detailed configuration of the fuel electrode side current collector 144:
A-3-1. Detailed configuration of the first tip 148 of the fuel electrode side current collector 144:
FIG. 8 is an enlarged explanatory view showing an XZ cross-sectional configuration of a part of the single cell 110 (X1 portion in FIG. 4). In the present embodiment, in the XZ cross section shown in FIG. 8, the first tip portion 148 of the fuel electrode side current collector 144 of each power generation unit 102 is the side connected to the connecting portion 147 in the electrode contact portion 145. It includes a first vertical extension portion 200 extending downward from the opposite side (X-axis negative direction side), and an X extension portion 201 extending downward from the lower end of the first vertical extension portion 200 in the X-axis negative direction.

In the present embodiment, in the XZ cross section shown in FIG. 8, the entire first tip portion 148 of the fuel pole side current collector 144 of each power generation unit 102 is connected to the spacer 149 in the X-axis direction. It is located on the opposite side of the. Further, in the present embodiment, in the same cross section (XZ cross section shown in FIG. 8), the first vertically extended portion 200 of the first tip portion 148 is in contact with the spacer 149. Therefore, in the present embodiment, in the same cross section (XZ cross section shown in FIG. 8), the spacer 149 of each power generation unit 102 is the first tip portion 148 of the fuel electrode side current collector 144 and the electrode contact portion 145. Is covered by the connecting portion 147 and the interconnector contact portion 146. The XZ cross section shown in FIG. 8 corresponds to a specific cross section within the scope of claims. In this embodiment, the X-axis direction corresponds to the second direction in the claims.

In the present embodiment, in the fuel pole side current collector 144 of each power generation unit 102, as shown in FIG. 8, a space 180 is formed between the connecting portion 147 of the fuel pole side current collector 144 and the spacer 149. It is configured as follows.

As shown in FIGS. 7 and 8, the first tip portion 148 of the fuel pole side current collector 144 of each power generation unit 102 is joined to the interconnector 150 by spot welding. More specifically, the lower surface of the first tip portion 148 of the fuel electrode side current collector 144 is joined to the interconnector 150 by spot welding. Therefore, as shown in FIG. 8, a welding mark 151 for joining the lower surface and the interconnector 150 is formed on the lower surface of the first tip portion 148 of the fuel electrode side current collector 144. In the present embodiment, the position of the center of the welding mark 151 is closer to the spacer 149 than the center CL1 in the X-axis direction at the first tip portion 148. In other words, the position where the first tip portion 148 is joined to the interconnector 150 (the position of the center of the welding mark 151) is closer to the spacer 149 than the center CL1 in the X-axis direction of the first tip portion 148. On the side.

A-3-2. Detailed configuration of the second tip 148A of the fuel electrode side current collector 144:
FIG. 9 is an explanatory view showing an enlarged XZ cross-sectional configuration of a part of the single cell 110 (X2 portion in FIG. 5). In the present embodiment, in the YZ cross section shown in FIG. 9, the second tip portion of the fuel electrode side current collector 144 connected to the end of the electrode contact portion 145 in the positive direction of the Y axis in each power generation unit 102. The 148A includes a second vertically extending portion 203 extending downward from the end of the electrode contact portion 145 in the positive direction of the Y axis, and a Y extending portion 204 extending downward from the lower end of the second vertically extending portion 203 in the positive direction of the Y axis. ing. In the present embodiment, the second vertically stretched portion 203 and the Y stretched portion 204 are located on the Y-axis positive direction side with respect to the spacer 149. In other words, the entire second tip portion 148A is located on the Y-axis positive direction side with respect to the spacer 149. In the present embodiment, the Y-axis positive direction corresponds to the specific one in the claims, and the Y-axis negative direction corresponds to the specific one in the claims.

In the present embodiment, in the same cross section (YZ cross section shown in FIG. 9), the second fuel electrode side current collector 144 connected to the Y-axis positive end of the electrode contact portion 145 in each power generation unit 102. The tip portion 148A of the above is joined to the interconnector 150. More specifically, the Y-extended portion 204 of the second tip portion 148A of the fuel electrode side current collector 144 is joined to the interconnector 150. Therefore, as shown in FIG. 9, a welding mark 151 for joining the lower surface and the interconnector 150 is formed on the lower surface of the Y extending portion 204 of the second tip portion 148A. Note that FIG. 7 shows a state before the second tip portion 148A of the fuel electrode side current collector 144 is joined to the interconnector 150 for convenience in order to facilitate understanding of the figure.

In the present embodiment, in the same cross section (YZ cross section shown in FIG. 9), the fuel electrode side current collector 144 connected to the end of the electrode contact portion 145 in the positive direction of the Y axis in each power generation unit 102. The position of the center of the welding mark 151 formed on the lower surface of the Y extending portion 204 of the tip portion 148A of 2 is closer to the spacer 149 than the center CL2 in the Y-axis direction of the second tip portion 148A. In other words, the position where the second tip 148A of the fuel electrode side current collector 144 connected to the Y-axis positive end of the electrode contact portion 145 is joined to the interconnector 150 (the center of the welding mark 151). The position) is closer to the spacer 149 than the center CL2 in the Y-axis direction at the second tip portion 148A.

In the present embodiment, in the same cross section (YZ cross section shown in FIG. 9), the fuel electrode side current collector 144 connected to the end of the electrode contact portion 145 in the negative direction of the Y axis in each power generation unit 102. The tip portion 148A of 2 is a second vertical extension portion 203 extending downward from the end of the electrode contact portion 145 in the negative direction of the Y axis, and a Y extension portion extending downward from the lower end of the second vertical extension portion 203 in the negative direction of the Y axis. It is equipped with 204. In the present embodiment, the second vertically stretched portion 203 and the Y stretched portion 204 are located on the negative side of the Y axis with respect to the spacer 149. In other words, the entire second tip portion 148A is located on the Y-axis negative direction side with respect to the spacer 149.

In the present embodiment, in the same cross section (YZ cross section shown in FIG. 9), the second fuel electrode side current collector 144 connected to the end in the negative direction of the Y axis of the electrode contact portion 145 in each power generation unit 102. The tip portion 148A of the above is joined to the interconnector 150. More specifically, the Y-extended portion 204 of the second tip portion 148A of the fuel electrode side current collector 144 is joined to the interconnector 150. Therefore, as shown in FIG. 9, a welding mark 151 for joining the lower surface and the interconnector 150 is formed on the lower surface of the Y extending portion 204 of the second tip portion 148A.

In the present embodiment, in the same cross section (YZ cross section shown in FIG. 9), the fuel electrode side current collector 144 connected to the end of the electrode contact portion 145 in the negative direction of the Y axis in each power generation unit 102. The position of the center of the welding mark 151 formed on the lower surface of the Y extending portion 204 of the tip portion 148A of 2 is a spacer 149 rather than the center CL3 in the Y-axis direction at the second tip portion 148A of the fuel electrode side current collector 144. It is near from. In other words, the position where the second tip 148A of the fuel electrode side current collector 144 connected to the end of the electrode contact portion 145 in the negative direction of the Y axis is joined to the interconnector 150 (the center of the welding mark 151). The position) is closer to the spacer 149 than the center CL3 in the Y-axis direction at the second tip portion 148A.

A-4. Effect of this embodiment:
As described above, the fuel cell stack 100 in the present embodiment includes a plurality of power generation units 102 arranged side by side in the vertical direction (Z-axis direction). Each power generation unit 102 includes a single cell 110, an interconnector 150, a fuel electrode side current collector 144, and a spacer 149. The single cell 110 includes an electrolyte layer 112, and air poles 114 and fuel poles 116 that face each other in the vertical direction with the electrolyte layer 112 in between. The interconnector 150 is arranged on the lower side (one in the vertical direction) with respect to the single cell 110. The fuel electrode side current collector 144 connects the interconnector contact portion 146 that contacts the surface of the interconnector 150, the electrode contact portion 145 that contacts the fuel electrode 116, and the interconnector contact portion 146 and the electrode contact portion 145. A unit 147 is provided. The fuel electrode side current collector 144 includes a first tip portion 148 connected to the side opposite to the side connected to the connecting portion 147 in the electrode contact portion 145. The spacer 149 is arranged between the interconnector contact portion 146 and the electrode contact portion 145 of the fuel electrode side current collector 144. In the XZ cross section shown in FIG. 8 (cross section parallel to the vertical direction (Z axis direction)), the entire first tip portion 148 of the fuel electrode side current collector 144 is in the X axis direction with respect to the spacer 149. It is located on the side opposite to the side of the connecting portion 147 in the vertical direction (direction perpendicular to the Z-axis direction).

Here, in the fuel cell stack 100, in the configuration in which the fuel electrode side current collector 144 does not include the first tip portion 148, the thermal expansion difference of each portion of the fuel cell stack 100 (for example, the fuel electrode 116, the interconnector 150) and the like Due to the above factors, the force for sandwiching the spacer 149 by the fuel electrode side current collector 144 cannot be secured, and the spacer 149 may be displaced in the X-axis direction. Therefore, in this configuration, the displacement of the spacer 149 in the X-axis direction may deteriorate the flow of gas in the fuel chamber 176, which in turn may reduce the power generation performance of the fuel cell stack 100.

On the other hand, in the fuel cell stack 100 of the present embodiment, as described above, in the XZ cross section shown in FIG. 8, the entire first tip portion 148 of the fuel electrode side current collector 144 is relative to the spacer 149. It is located on the side opposite to the side of the connecting portion 147 in the X-axis direction. Therefore, the presence of the first tip portion 148 of the fuel electrode side current collector 144 suppresses the displacement of the spacer 149 in the X-axis direction. Therefore, according to the fuel cell stack 100 of the present embodiment, the deterioration of the power generation performance of the fuel cell stack 100 due to the deterioration of the gas flow in the fuel chamber 176 due to the displacement of the spacer 149 in the X-axis direction is suppressed. can do.

Further, in the fuel cell stack 100 of the present embodiment, the first tip portion 148 of the fuel electrode side current collector 144 of each power generation unit 102 is joined to the interconnector 150. Therefore, according to the fuel cell stack 100 of the present embodiment, the displacement of the spacer 149 in the X-axis direction can be suppressed more effectively.

Further, in the fuel cell stack 100 of the present embodiment, in the YZ cross section shown in FIG. 9 (cross section perpendicular to the XZ cross section shown in FIG. 8), the fuel pole side current collector 144 of each power generation unit 102 is A second tip 148A connected to the end of the electrode contact portion 145 in the Y-axis direction (the direction perpendicular to the vertical direction in the YZ cross section shown in FIG. 9), at least part of which is relative to the spacer 149. It includes a second tip portion 148A located on the side in the Y-axis direction (the direction perpendicular to the vertical direction in the YZ cross section shown in FIG. 9).

Here, in the fuel cell stack 100, in the configuration in which the fuel electrode side current collector 144 does not include the second tip portion 148A, the thermal expansion difference of each portion of the fuel cell stack 100 (for example, the fuel electrode 116, the interconnector 150) and the like Due to the above factors, the force for sandwiching the spacer 149 by the fuel electrode side current collector 144 cannot be secured, and the spacer 149 may be displaced in the Y-axis direction. Therefore, in this configuration, the displacement of the spacer 149 in the Y-axis direction may deteriorate the flow of gas in the fuel chamber 176, which in turn may deteriorate the power generation performance of the fuel cell stack 100.

On the other hand, in the fuel cell stack 100 of the present embodiment, as described above, in the YZ cross section shown in FIG. 9, the fuel electrode side current collector 144 of each power generation unit 102 has a positive Y-axis at the electrode contact portion 145. It is a second tip portion 148A connected to the end in the direction, and includes a second tip portion 148A which is entirely located on the Y-axis positive direction side with respect to the spacer 149. Therefore, according to the fuel cell stack 100 of the present embodiment, the displacement of the spacer 149 in the positive Y-axis direction can be suppressed. Further, as described above, in the fuel cell stack 100 of the present embodiment, in the same cross section (YZ cross section shown in FIG. 9), the fuel electrode side current collector 144 of each power generation unit 102 is Y at the electrode contact portion 145. It is a second tip portion 148A connected to the end in the negative axis direction, and includes a second tip portion 148A which is entirely located on the negative direction side of the Y axis with respect to the spacer 149. Therefore, according to the fuel cell stack 100 of the present embodiment, the displacement of the spacer 149 in the negative Y-axis direction can be suppressed.

Further, as shown in FIG. 9, in the fuel cell stack 100 of the present embodiment, the fuel pole side current collector 144 (second tip portion 148A of the fuel pole side current collector 144) of each power generation unit 102 is a spacer. It is joined to the interconnector 150 on the Y-axis direction (the direction perpendicular to the XZ cross section shown in FIG. 8) with respect to 149. Therefore, according to the fuel cell stack 100 of the present embodiment, the displacement of the spacer 149 in the Y-axis direction can be suppressed.

Further, in the fuel cell stack 100 of the present embodiment, the position where the first tip portion 148 of the fuel pole side current collector 144 of each power generation unit 102 is joined to the interconnector 150 is the fuel pole side current collector 144. The side closer to the spacer 149 than the center CL1 in the X-axis direction (the direction perpendicular to the vertical direction in the XZ cross section shown in FIG. 8; the direction perpendicular to the vertical direction and the Y-axis direction) at the first tip portion 148 of the fuel cell. Is. Therefore, the position where the first tip 148 of the fuel electrode side current collector 144 of each power generation unit 102 is joined to the interconnector 150 is relatively close to the spacer 149. Therefore, according to the fuel cell stack 100 of the present embodiment, the displacement of the spacer 149 in the X-axis direction can be suppressed more effectively.

Further, in the fuel cell stack 100 of the present embodiment, in the fuel pole side current collector 144 of each power generation unit 102, a space 180 is formed between the connecting portion 147 of the fuel pole side current collector 144 and the spacer 149. It is configured as follows.

When the space between the fuel pole 116 and the interconnector 150 is widened due to the difference in thermal expansion of each part of the fuel cell stack 100 (for example, the fuel pole 116 and the interconnector 150), the electrodes of the fuel pole 116 and the fuel pole side current collector 144 The contact portion 145 may be peeled off. As a result, the contact area between the fuel pole 116 and the electrode contact portion 145 of the fuel pole side current collector 144 becomes small, which may reduce the power generation performance of the fuel cell stack 100.

On the other hand, in the fuel cell stack 100 of the present embodiment, as described above, in the fuel electrode side current collector 144, a space 180 is formed between the connecting portion 147 of the fuel electrode side current collector 144 and the spacer 149. It is configured to. Therefore, of the electrode contact portion 145 of the fuel electrode side current collector 144, the portion on the connecting portion 147 side and the portion of the interconnector contact portion 146 on the connecting portion 147 side are both in contact with the fuel pole 116. Since there is no fuel electrode 116, it is possible to extend freely to some extent when the space between the fuel electrode 116 and the interconnector 150 is widened. Therefore, according to the fuel cell stack 100 of the present embodiment, the contact area between the fuel pole 116 and the electrode contact portion 145 of the fuel pole side current collector 144 is reduced by widening the space between the fuel pole 116 and the interconnector 150. It is possible to suppress the deterioration of the power generation performance of the fuel cell stack 100.

Further, in the fuel cell stack 100 of the present embodiment, the first tip portion 148 of the fuel electrode side current collector 144 of the power generation unit 102 is in contact with the spacer 149. Therefore, according to the fuel cell stack 100 of the present embodiment, the displacement of the spacer 149 in the X-axis direction can be suppressed more effectively.

B. Modification example:
The technique disclosed in the present specification is not limited to the above-described embodiment, and can be transformed into various forms without departing from the gist thereof. For example, the following modifications are also possible.

In the above embodiment (or a modified example, the same applies hereinafter), the electrode contact portion 145 is configured to be in contact with the surface of the fuel electrode 116 on the side opposite to the side facing the electrolyte layer 112 via a bonding material. May be good. Further, in the above embodiment, the interconnector contact portion 146 may be configured to be in contact with the surface of the interconnector 150 on the side facing the fuel electrode 116 via a bonding material.

Further, in the above embodiment, the interconnector contact portion 146 of the fuel electrode side current collector 144, the electrode contact portion 145, the connecting portion 147, and the first tip portion 148 are integrally formed of the interconnector. Any or all of the contact portion 146, the electrode contact portion 145, and the connecting portion 147 may be composed of separate members.

Further, in the above embodiment, for all the fuel electrode side current collectors 144 included in the fuel cell stack 100, the interconnector contact portion 146, the electrode contact portion 145, the connecting portion 147, and the first tip portion 148 , A second tip portion 148A is provided, but at least one fuel pole side current collector 144 included in the fuel cell stack 100 includes an interconnector contact portion 146, an electrode contact portion 145, and a connecting portion 147. And / or a configuration including a first tip portion 148 and / or a second tip portion 148A, the fuel electrode side current collector 144 is arranged between the electrode contact portion 145 and the interconnector contact portion 146. It is possible to suppress the misalignment of the spacer 149.

For example, in the above embodiment, for at least one power generation unit 102 included in the fuel cell stack 100, the interconnector contact portion 146, the electrode contact portion 145, the connecting portion 147, the first tip portion 148 and / or the first If the fuel electrode side current collector 144 including the tip portion 148A of 2 is provided, the displacement of the spacer 149 of the power generation unit 102 including the fuel electrode side current collector 144 can be suppressed. It should be noted that 50% or more (more preferably 80% or more) of the number of fuel electrode side current collectors 144 included in the power generation unit 102 is such a configuration (interconnector contact portion 146). It is particularly preferable that the electrode contact portion 145, the connecting portion 147, and the first tip portion 148 and / or the second tip portion 148A are provided). Further, a power generation unit having such a configuration in which 50% or more (more preferably 80% or more) of the number of fuel pole side current collectors 144 included in the power generation unit 102 is the fuel pole side current collector 144. It is particularly preferable that the number of 102 is 20% or more (more preferably 50% or more, still more preferably 80%) of the number of power generation units 102 included in the fuel cell stack 100.

Further, in the above embodiment, in the XZ cross section shown in FIG. 8, only a part of the first tip portion 148 of the fuel electrode side current collector 144 is the connecting portion 147 in the X-axis direction with respect to the spacer 149. The configuration may be located on the side opposite to the side. Also in this configuration, the presence of the first tip portion 148 of the fuel electrode side current collector 144 can suppress the displacement of the spacer 149 in the X-axis direction.

Further, in the above embodiment, in the YZ cross section shown in FIG. 9, only a part of the second tip portion 148A of the fuel electrode side current collector 144 is located on the Y-axis direction side with respect to the spacer 149. It may be a configuration. Also in this configuration, the presence of the second tip portion 148A of the fuel electrode side current collector 144 can suppress the displacement of the spacer 149 in the Y-axis direction.

Further, in the above embodiment, the fuel pole side current collector 144 is configured so that a space 180 is formed between the connecting portion 147 of the fuel pole side current collector 144 and the spacer 149, but the fuel pole side. The connection portion 147 of the fuel electrode side current collector 144 and the spacer 149 may be in contact with each other so that a space 180 is not formed between the connection portion 147 of the current collector 144 and the spacer 149.

In the above embodiment, the position where the first tip 148 of the fuel pole side current collector 144 is joined to the interconnector 150 is in the X-axis direction at the first tip 148 of the fuel pole side current collector 144. It may be the central CL1. Even in this configuration, the displacement of the spacer 149 in the X-axis direction can be effectively suppressed. Further, in the above embodiment, the position where the first tip portion 148 of the fuel pole side current collector 144 is joined to the interconnector 150 is the X-axis of the first tip portion 148 of the fuel pole side current collector 144. It may be the center CL1 of the direction. Even in this configuration, the displacement of the spacer 149 in the X-axis direction can be effectively suppressed.

Further, in the above embodiment, the position where the first tip portion 148 of the fuel pole side current collector 144 is joined to the interconnector 150 is the X-axis of the first tip portion 148 of the fuel pole side current collector 144. A configuration may be adopted that is farther from the spacer 149 than the center CL1 in the direction (the direction perpendicular to the vertical direction in the XZ cross section shown in FIG. 8; the direction perpendicular to the vertical direction and the Y-axis direction). In this configuration, of the first tip 148 of the fuel electrode side current collector 144, the portion closer to the spacer 149 than the position where the first tip 148 is joined to the interconnector 150 is an inter. Since it is not joined to the connector 150, it can be freely extended to some extent when the space between the fuel electrode 116 and the interconnector 150 is widened. Therefore, according to this configuration, the portion of the first tip portion 148 of the fuel electrode side current collector 144 that is not joined to the interconnector 150 is relatively long, so that the fuel electrode 116 and the interconnector 150 are combined. It is possible to more effectively suppress the decrease in the contact area between the fuel electrode 116 and the electrode contact portion 145 of the fuel electrode side current collector 144 when the space is widened, and by extension, the power generation performance of the fuel cell stack 100. The decrease can be suppressed more effectively.

In the above embodiment, the fuel electrode side current collector 144 is connected to the second tip portion 148A connected to the Y-axis positive end of the electrode contact portion 145 and to the Y-axis negative end of the electrode contact portion 145. The configuration may include only one of the connected second tip 148A. Also in this configuration, the presence of the second tip portion 148A of the fuel electrode side current collector 144 can suppress the displacement of the spacer 149 in the Y-axis direction.

Further, the fuel cell stack 100 of the above embodiment has a configuration in which the fuel electrode side current collector 144 is provided at the second tip portion 148A, thereby suppressing the displacement of the spacer 149 in the Y-axis direction. In the fuel cell stack 100 of the embodiment, as shown in FIG. 10, the fuel pole side current collector 144 does not have a second tip 148A, and the spacer 149 extends to the outside of the fuel pole side current collector 144 in a vertical view. A configuration having a protruding portion 149A which is a protruding portion and which overlaps with the fuel electrode side current collector 144 in the X-axis direction view (direction view perpendicular to the vertical direction) may be adopted. The X-axis direction view referred to here means "when viewed from a direction parallel to the X-axis direction" (the same applies to "X-axis direction view" below). In this configuration, the presence of the protrusion 149A of the spacer 149 suppresses the displacement of the spacer 149 in the Y-axis direction. Therefore, even in this configuration, the displacement of the spacer 149 in the Y-axis direction can be suppressed.

Further, in the above embodiment, the fuel electrode side current collector 144 has a cross section parallel to the vertical direction and is different from the XZ cross section shown in FIG. 8 (hereinafter, simply referred to as "another cross section"). ), A configuration including an interconnector contact portion 146, an electrode contact portion 145, a connecting portion 147, and a first tip portion 148 and / or a second tip portion 148A may be adopted. In this configuration, the presence of the first tip portion 148 of the other cross section can suppress the misalignment of the spacer 149 in the direction perpendicular to the vertical direction in the other cross section, and the second tip of the other cross section. The presence of the portion 148A can suppress the misalignment of the spacer 149 in the direction perpendicular to the other cross section.

In the fuel cell stack 100 of the above embodiment, the air electrode side current collector 134 is arranged on the upper side (one of the vertical directions) of the single cell 110 (hereinafter, the interconnector 150 is particularly referred to as the interconnector 150). When pointing, an interconnector contact portion that contacts the surface of the "upper interconnector 150"), an electrode contact portion that contacts the air electrode 114, and a connecting portion that connects the interconnector contact portion and the electrode contact portion. The interconnector is provided with a first tip portion (hereinafter, referred to as "first tip portion on the air electrode side") connected to the side of the electrode contact portion opposite to the side connected to the connecting portion. A configuration may be adopted in which a spacer (a member having the same material and shape as the spacer 149; hereinafter, referred to as an “air electrode side spacer”) is arranged between the contact portion and the electrode contact portion. Also in this configuration, for the same reason as in the case of the above embodiment, the positional deviation of the spacer on the air electrode side in the X-axis direction and the Y-axis direction becomes a problem, but due to the presence of the first tip portion on the air electrode side, there is a problem. It is possible to suppress the displacement of the spacer 149 in the X-axis direction. Further, in addition to or in addition to such a configuration, in the fuel cell stack 100 of the above embodiment, the air electrode side current collector 134 is connected to the end of the electrode contact portion 145 in the Y-axis direction. A second tip portion (hereinafter, referred to as “second tip portion on the air electrode side”) is provided, which is at least a part of the tip portion located on the Y-axis direction side with respect to the air electrode side spacer. The configuration may be adopted. Also in this configuration, for the same reason as in the case of the above embodiment, the presence of the second tip portion on the air electrode side can suppress the displacement of the air electrode side spacer in the Y-axis direction.

Further, in the above embodiment, the SOFC that generates power by utilizing the electrochemical reaction between hydrogen contained in the fuel gas and oxygen contained in the oxidizing agent gas is targeted, but the present invention comprises an electrolysis reaction of water. It is also applicable to an electrolytic cell unit, which is the smallest unit of a solid oxide fuel cell (SOEC) that uses it to generate hydrogen, and an electrolytic cell stack having a plurality of electrolytic cell units. The configuration of the electrolytic cell stack is not described in detail here because it is known as described in, for example, Japanese Patent Application Laid-Open No. 2016-81813, but is generally the same as the fuel cell stack 100 in the above-described embodiment. It is a configuration. That is, the fuel cell stack 100 in the above-described embodiment may be read as an electrolytic cell stack, and the power generation unit 102 may be read as an electrolytic cell unit.

22: Bolt 24: Nut 26: Insulation sheet 27: Gas passage member 28: Main body 29: Branch 100: Fuel cell stack 102: Power generation unit 104: End plate 106: End plate 108: Communication hole 110: Single cell 112: Electrolyte layer 114: Air pole 116: Fuel pole 120: Separator 124: Joint 130: Air pole side frame 132: Oxidizing gas supply communication hole 133: Oxidizing agent gas discharge communication hole 134: Air pole side current collector 140: Fuel Pole side frame 142: Fuel gas supply communication hole 143: Fuel gas discharge communication hole 144: Fuel pole side current collector 145: Electrode contact part 146: Interconnector contact part 147: Connection part 148: First tip part 148A: No. 2 tip 149: spacer 149A: protrusion 150: interconnector 151: welding mark 161: oxidant gas supply manifold 162: oxidant gas discharge manifold 166: air chamber 171: fuel gas supply manifold 172: fuel gas discharge manifold 176 : Fuel chamber 200: First vertical stretching section 201: X stretching section 203: Second vertical stretching section 204: Y stretching section FG: Fuel gas FOG: Fuel off gas OG: Oxidizing gas OOG: Oxidating agent off gas

Claims (9)

A single cell containing an electrolyte layer and an air electrode and a fuel electrode facing each other in the first direction across the electrolyte layer.
A first conductive member arranged on the side in the first direction with respect to the single cell,
A first contact portion that contacts the surface of the first conductive member, a second contact portion that contacts the first electrode that is one of the air electrode and the fuel electrode, and the first contact portion. A second conductive member including a connecting portion that connects the second contact portion and the second contact portion, and
In an electrochemical reaction cell stack in which a plurality of electrochemical reaction units including a spacer arranged between the first contact portion and the second contact portion of the second conductive member are arranged side by side.
The second conductive member includes a first tip portion connected to a side opposite to the side connected to the connecting portion in the second contact portion.
When at least one cross section parallel to the first direction is defined as a specific cross section and the direction perpendicular to the first direction in the specific cross section is defined as a second direction,
In the specific cross section, at least a part of the first tip of the second conductive member of the specific reaction unit, which is at least one electrochemical reaction unit, is the said in the second direction with respect to the spacer. Located on the opposite side of the connecting part,
It is characterized by an electrochemical reaction cell stack. In the electrochemical reaction cell stack according to claim 1,
The first tip portion of the second conductive member of the specific reaction unit is joined to the first conductive member.
It is characterized by an electrochemical reaction cell stack. In the electrochemical reaction cell stack according to claim 2.
When the direction perpendicular to the specific cross section is set as the third direction,
In a cross section perpendicular to the specific cross section, the second conductive member of the specific reaction unit is connected to at least one specific side of the third direction end of the second contact. A second tip that is at least partially located on the specific one side of the third direction with respect to the spacer.
It is characterized by an electrochemical reaction cell stack. In the electrochemical reaction cell stack according to claim 3,
The second conductive member of the specific reaction unit is joined to the first conductive member on the side in the third direction with respect to the spacer.
It is characterized by an electrochemical reaction cell stack. In the electrochemical reaction cell stack according to claim 1 or 2.
The spacer of the specific reaction unit has a portion that protrudes to the outside of the second conductive member in the first directional view and has a portion that overlaps the second conductive member in the second directional view.
It is characterized by an electrochemical reaction cell stack. In the electrochemical reaction cell stack according to claim 2.
The position where the first tip of the second conductive member of the specific reaction unit is joined to the first conductive member is the position of the first tip of the second conductive member at the first tip. The center in two directions or the side closer to the spacer than the center,
It is characterized by an electrochemical reaction cell stack. In the electrochemical reaction cell stack according to claim 2.
The position where the first tip of the second conductive member of the specific reaction unit is joined to the first conductive member is the position of the first tip of the second conductive member at the first tip. The center in two directions or the side farther from the spacer than the center,
It is characterized by an electrochemical reaction cell stack. In the electrochemical reaction cell stack according to any one of claims 1 to 7.
The second conductive member of the specific reaction unit is configured such that a space is formed between the connecting portion of the second conductive member and the spacer.
It is characterized by an electrochemical reaction cell stack. In the electrochemical reaction cell stack according to any one of claims 1 to 8.
The first tip is in contact with the spacer.
It is characterized by an electrochemical reaction cell stack.

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