JP7301094B2 - Electrochemical reaction cell stack - Google Patents

Description

The technology disclosed herein relates to an electrochemical reaction cell stack.

A solid oxide fuel cell (hereinafter referred to as "SOFC") is known as one of fuel cells that generate electricity using an electrochemical reaction between hydrogen and oxygen. SOFCs are 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. The power generation unit includes a single fuel cell (hereinafter simply referred to as "single cell"). A single cell includes an electrolyte layer, and an air electrode and a fuel electrode facing each other in a predetermined direction (hereinafter referred to as "first direction") with the electrolyte layer interposed therebetween.

Each power generation unit 102 further includes an interconnector disposed on the first direction side with respect to the single cell, a fuel electrode side current collector positioned between the single cell and the interconnector, and a single cell and the interconnector. and a spacer positioned between. The interconnector is made of ferritic stainless steel, for example. The fuel electrode side current collector is made of, for example, nickel, a nickel alloy, stainless steel, or the like. The interconnector and the fuel electrode side current collector have different coefficients of thermal expansion. The spacer extends in a predetermined direction when viewed from the first direction.

The fuel-electrode-side current collector includes an electrode-side contact portion, an opposite-side contact portion, a connecting portion, and a tip portion (see Patent Document 1, for example). The electrode-side contact portion is in contact with the fuel electrode, and is in contact with the spacer on the side opposite to the fuel electrode. The contact on the opposite side contacts the interconnector. The connecting portion connects the electrode-side contact portion and the opposite-side contact portion. The tip portion has a portion connected to the electrode-side contact portion and located on the side opposite to the connecting portion with respect to the spacer. The tip portion extends in the direction in which the spacer extends (hereinafter referred to as "spacer extending direction") when viewed from the first direction. Each power generation unit includes a plurality of joints that join the tip of the fuel electrode side current collector and the interconnector. The plurality of joints are arranged side by side at intervals along the extending direction of the spacer when viewed from the first direction. When viewed from the first direction, the length of the front end portion of the fuel electrode-side current collector in the spacer extension direction is uniform.

Japanese Patent Application Laid-Open No. 2021-022471

In the conventional fuel cell stack described above, for example, when a temperature change occurs during operation, the interconnector and the fuel electrode side current collector (more strictly, the tip portion of the fuel electrode side current collector) As a result of the deformation of the tip portion of the fuel electrode side current collector due to the difference in thermal expansion between the A portion between the cells (in other words, a portion not joined to the interconnector; hereinafter referred to as a “non-joint portion”) contacts the single cell, and as a result, the non-joint portion separates the single cell and the fuel chamber (single cell). space between the cell and the interconnector) may be blocked. If the space between the single cell and the fuel chamber is blocked in this manner, the reaction gas flowing through the fuel chamber (the space between the single cell and the interconnector) is hindered from flowing into the single cell. Therefore, in this fuel cell stack, the flowability of the reaction gas flowing through the fuel chamber into the unit cells is hindered, and this may reduce the performance of the fuel cell stack.

Such a problem can be solved by replacing the "fuel electrode" with the "air electrode" and replacing the "fuel electrode side current collector" with the "air electrode side current collector" in the above fuel cell stack. It is a common problem with some fuel cell stacks. In addition, such a problem is solved by electrolysis having a plurality of electrolytic cell units, which are structural units of a solid oxide type electrolytic cell (hereinafter referred to as "SOEC") that generates hydrogen using the electrolysis reaction of water. This is also a common problem with cell stacks. In this specification, the fuel cell single cell and the electrolytic single cell are collectively referred to as the electrochemical reaction single cell, the power generation unit and the electrolytic cell unit are collectively referred to as the electrochemical reaction unit, and the fuel cell stack and the electrolytic cell are collectively referred to as the electrochemical reaction unit. The stack is collectively called an electrochemical reaction cell stack. Moreover, such a problem is not limited to SOFCs and SOECs, but is common to other types of electrochemical reaction cell stacks.

This specification discloses a technology capable of solving the above-described problems.

The technology disclosed in this specification can be implemented as the following modes.

(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 with the electrolyte layer interposed therebetween; a first conductive member arranged on the first direction side with respect to the cell; An electrochemical reaction cell stack in which a plurality of electrochemical reaction units are arranged side by side, each comprising a second conductive member different from the coefficient and a spacer positioned between the unit cell and the first conductive member, The second conductive member in the specific reaction unit that is at least one of the electrochemical reaction units is in contact with a specific electrode that is one of the air electrode and the fuel electrode, and the second conductive member is in contact with the specific electrode on the side opposite to the specific electrode. an electrode-side contact portion that contacts a spacer, an opposite-side contact portion that contacts the first conductive member, a connecting portion that connects the electrode-side contact portion and the opposite-side contact portion, and is connected to the electrode-side contact portion, and a tip portion having a portion located on the opposite side of the connecting portion with respect to the spacer, the tip portion extending in a specific direction along the spacer when viewed in the first direction. In an electrochemical reaction cell stack comprising: a plurality of joints arranged side by side at intervals along the specific direction, one of the plurality of joints being a first joint, and the joint positioned next to the first joint; is a second joint, and a direction orthogonal to an imaginary straight line passing through the center of the first joint and the center of the second joint when viewed in the first direction is a second direction, A first outer intersection point that intersects a contour line on the opposite side of the electrode-side contact portion of the distal end portion among the imaginary straight lines in the second direction overlapping the first joint portion, and a point that is closest to the first joint portion. An imaginary line segment connecting a first inner intersection point that intersects the surface of the spacer is defined as a first line segment, and among imaginary straight lines in the second direction overlapping the second joint portion, the electrode side contact of the tip portion is performed. An imaginary line segment connecting a second outer intersection point that intersects the contour line opposite to the part and a second inner intersection point that intersects the surface of the spacer closest to the second joint portion is defined as a second line segment, An imaginary line segment connecting the first outer intersection point and the second outer intersection point is defined as a third line segment, an imaginary line segment connecting the first inner intersection point and the second inner intersection point is defined as a fourth line segment, and the first When a region surrounded by a line segment, the second line segment, the third line segment, and the fourth line segment is defined as a specific region, the tip portion is missing in a part of the specific region. .

In the present electrochemical reaction cell stack, as described above, the second conductive member has a tip portion having a portion located on the opposite side of the connecting portion with respect to the spacer. Therefore, it is possible to suppress the displacement of the spacer in a predetermined direction (the direction in which the connecting portion of the second conductive member and the spacer are arranged). It is possible to suppress the deterioration of the performance of the electrochemical reaction cell stack due to deterioration of the gas flow in the space between the conductive member.

By the way, in the above-described conventional fuel cell stack (Japanese Patent Application Laid-Open No. 2021-022471), the specific region is not deficient. Therefore, in this fuel cell stack, for example, when a temperature change occurs during operation, thermal expansion between the first conductive member and the second conductive member (more strictly, the tip portion of the second conductive member) As a result of the deformation of the tip portion of the second conductive member due to the difference, the non-joint portion of the tip portion (the portion between the first joint portion and the second joint portion of the tip portion) comes into contact with the single cell. As a result, the unbonded portion may block the space between the single cell and the gas chamber (the space between the single cell and the first conductive member). If the space between the single cell and the gas chamber is blocked in this manner, the reaction gas flowing through the gas chamber (the space between the single cell and the first conductive member) is hindered from flowing into the single cell. Therefore, in this fuel cell stack, the flowability of the reaction gas flowing through the gas chamber into the single cells is hindered, which may reduce the performance of the electrochemical reaction cell stack.

On the other hand, in this electrochemical reaction cell stack, as described above, a part of the specific region is defective. Therefore, due to the difference in thermal expansion between the first conductive member and the second conductive member, the non-joint portion of the tip portion (the portion between the first joint portion and the second joint portion of the tip portion) is deformed and the non-bonded portion of the tip comes into contact with the single cell, the contact area between the non-bonded portion of the tip and the single cell is smaller than that of the configuration in which the specific region is not damaged, so the gas Inhibition of the flowability of the reactant gas flowing through the chamber into the single cell is suppressed. Therefore, according to the present electrochemical reaction cell stack, the non-joint portion of the tip portion deforms due to the difference in thermal expansion between the first conductive member and the second conductive member, and the non-joint portion of the tip portion becomes single. It is possible to suppress deterioration in the performance of the electrochemical reaction cell stack due to contact with the cells.

(2) In the above electrochemical reaction cell stack, the length of the first line segment in the second direction is L1, the length of the second line segment in the second direction is L2, and the first A virtual line segment passing through the missing portion of the tip portion in the second direction between the line segment and the second line segment, the third line segment and the fourth line segment Among the connecting virtual line segments, the length of the portion overlapping the electrode side contact portion and the tip portion is L3, the length L3/length L1 is the first ratio A1, and the length L3/length L2 is the second ratio. When the ratio is A2, both the first ratio A1 and the second ratio A2 may be 0.8 or less. In this electrochemical reaction cell stack, the contact area between the non-bonded portion at the tip and the single cell is particularly small, and it is particularly effective in hindering the flow of the reaction gas flowing through the gas chamber into the single cell. Suppressed. Therefore, according to the present electrochemical reaction cell stack, the non-bonded portion of the tip is deformed due to the difference in thermal expansion between the first conductive member and the second conductive member. It is possible to suppress deterioration in the performance of the electrochemical reaction cell stack due to contact of the non-junction with the single cell.

(3) In the above electrochemical reaction cell stack, a through hole communicating with a space on the opposite side of the connecting portion to the spacer and facing the single cell is formed in the connecting portion. It is also possible to adopt a configuration in which According to this electrochemical reaction cell stack, it is possible to further improve the flowability of the reaction gas flowing in the gas chamber (the space on the side opposite to the spacer with respect to the connecting part) into the single cell. The performance of the reaction cell stack can be further improved.

The technology disclosed in this specification can be implemented in various forms, for example, an electrochemical reaction cell stack (fuel cell stack or electrolytic cell stack), a method for manufacturing an electrochemical reaction cell stack, and the like. can be realized in the form of

1 is a perspective view showing an external configuration of a fuel cell stack 100 according to this embodiment; FIG. FIG. 2 is an explanatory view showing the XZ cross-sectional configuration of the fuel cell stack 100 at the position II-II in FIG. 1; FIG. 2 is an explanatory view showing the YZ cross-sectional configuration of the fuel cell stack 100 at the position III-III in FIG. 1; FIG. 3 is an explanatory diagram showing the 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 ; FIG. 4 is an explanatory diagram showing the YZ cross-sectional configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. 3 ; FIG. 6 is an explanatory diagram showing the XY cross-sectional configuration of the power generation unit 102 at the position VI-VI in FIG. 5; FIG. 6 is an explanatory view showing the XY cross-sectional configuration of the power generation unit 102 at the position of VII-VII in FIG. 5; FIG. 5 is an explanatory diagram showing an enlarged XZ cross-sectional configuration of a portion (X1 section in FIG. 4) of the single cell 110; FIG. 6 is an explanatory diagram showing an enlarged YZ cross-sectional configuration of a portion (X2 section in FIG. 5) of the single cell 110; FIG. 8 is an explanatory diagram showing an enlarged XY cross-sectional configuration of a portion (X3 section in FIG. 7) of the single cell 110; FIG. 11 is an explanatory diagram showing the YZ cross-sectional configuration of the unit cell 110 at the position XI-XI in FIG. 10; FIG. 8 is an explanatory diagram showing an enlarged XY cross-sectional configuration of a part of the unit cell 110 (the part corresponding to the X3 part in FIG. 7) in the modified example; 13 is an explanatory diagram showing the YZ cross-sectional configuration of the power generation unit 102 at the position of XIII-XIII in FIG. 12; FIG.

A. Embodiment:
A-1. composition:
(Configuration of fuel cell stack 100)
FIG. 1 is a perspective view showing the external configuration of the fuel cell stack 100 in this embodiment, and FIG. 2 is an explanatory diagram showing the XZ cross-sectional configuration of the fuel cell stack 100 at the position II-II in FIG. FIG. 3 is an explanatory diagram showing the YZ cross-sectional configuration of the fuel cell stack 100 at the position III-III in FIG. Each figure shows mutually orthogonal XYZ axes for specifying directions. In this specification, for the sake of convenience, the positive direction of the Z-axis is referred to as the "upward direction" and the negative direction of the Z-axis is referred to as the "downward direction." It may be installed in different orientations. The same applies to FIG. 4 and subsequent figures. Note that the Z-axis direction is an example of a first direction in the scope of claims. A fuel cell stack is an example of an electrochemical reaction cell stack in the claims.

The fuel cell stack 100 includes a plurality of (seven in this embodiment) power generation units 102 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 (the Z-axis direction in this embodiment). A 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 Z-axis direction are formed in the peripheral edge portion around the Z-axis direction of each layer (the power generating unit 102, the end plates 104 and 106) constituting the fuel cell stack 100. Corresponding holes formed in each layer communicate with each other in the Z-axis direction to form a communication hole 108 extending in the Z-axis 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 constitute the communication holes 108 are also referred to as "communication holes 108".

A bolt 22 extending in the Z-axis direction is inserted into each communication hole 108 , and the fuel cell stack 100 is fastened by the bolt 22 and nuts 24 fitted on both sides of the bolt 22 . 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 constituting the upper end of the fuel cell stack 100, and between the bolt An insulating sheet 26 is interposed between the nut 24 fitted to the other side (lower side) of the fuel cell stack 22 and the lower surface of the end plate 106 forming the lower end of the fuel cell stack 100 . However, at a location where a gas passage member 27, which will be described later, is provided, between the nut 24 and the surface of the end plate 106, the insulating sheets disposed above and below the gas passage member 27 and the gas passage member 27, respectively. 26 intervenes. The insulating sheet 26 is composed of, for example, a mica sheet, a ceramic fiber sheet, a ceramic powder sheet, a glass sheet, a glass-ceramic composite, 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, one side of the outer circumference of the fuel cell stack 100 around the Z-axis direction (the side on the positive side of the X-axis among the two sides parallel to the Y-axis) is near the midpoint. The space formed by the positioned bolt 22 (bolt 22A) and the communication hole 108 into which the bolt 22A is inserted receives the oxidant gas OG from the outside of the fuel cell stack 100, and the oxidant gas OG is introduced into each space. It functions as an oxidant gas supply manifold 161 that is a gas flow path for supplying to the power generation unit 102, and the side opposite to the side (the side on the negative side of the X axis among the two sides parallel to the Y axis) The space formed by the bolt 22 (bolt 22B) positioned near the point and the communication hole 108 into which the bolt 22B is inserted is the oxidant offgas OOG which is the gas discharged from the air chamber 166 of each power generation unit 102. to the outside of the fuel cell stack 100 as an oxidizing gas discharge manifold 162 . In this embodiment, for example, air is used as the oxidant gas OG.

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

Four gas passage members 27 are provided in the fuel cell stack 100 . Each gas passage member 27 has a hollow tubular body portion 28 and a hollow tubular branch portion 29 branched from a side surface of the main body portion 28 . A hole in the branch portion 29 communicates with a hole in 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 body portion 28 of the gas passage member 27 arranged at the position of the bolt 22A forming the oxidizing gas supply manifold 161 communicates with the oxidizing gas supply manifold 161. A hole in the body portion 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 body portion 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 the fuel gas A hole in the body portion 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 .

(Configuration of end plates 104, 106)
The pair of end plates 104 and 106 are substantially rectangular plate-shaped conductive members, and are made of, for example, stainless steel. One end plate 104 is arranged above the uppermost power generating unit 102 and the other end plate 106 is arranged below the lowermost power generating unit 102 . A pair of end plates 104 and 106 hold a plurality of power generation units 102 in a pressed state. The upper end plate 104 functions as the positive side output terminal of the fuel cell stack 100 , and the lower end plate 106 functions as the negative side output terminal of the fuel cell stack 100 .

(Configuration of power generation unit 102)
4 is an explanatory diagram showing the 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. FIG. 3 is an explanatory diagram showing a YZ cross-sectional configuration of two power generation units 102; 6 is an explanatory view showing the XY cross-sectional configuration of the power generation unit 102 at the position VI-VI in FIGS. 4 and 5, and FIG. 7 is the power generation unit at the position VII-VII in FIGS. 102 is an explanatory diagram showing an XY cross-sectional configuration; FIG. Note that the partially enlarged view shown in the upper part of FIG. 7 is not a view showing a cross-sectional structure but a perspective view.

As shown in FIGS. 4 and 5, the power generation unit 102 includes a single cell 110, a separator 120, an air electrode side frame 130, an air electrode side current collector 134, an anode side frame 140, an anode side It has current collectors 144 , spacers 149 , and a pair of interconnectors 150 forming the top layer and the bottom layer of the power generation unit 102 . It can be said that the interconnector 150 is arranged on the Z-axis direction side with respect to the single cell 110 . The separator 120, the air electrode side frame 130, the fuel electrode side frame 140, and the interconnector 150 are provided with holes corresponding to the communication holes 108 through which the bolts 22 are inserted. The power generation unit 102 is an example of an electrochemical reaction unit in the scope of claims.

The interconnector 150 is a substantially rectangular plate-shaped conductive member, and is made of, for example, ferritic stainless steel. The interconnector 150 ensures electrical continuity between the power generating units 102 and prevents mixing of reaction gases between the power generating units 102 . In this embodiment, when two power generation units 102 are arranged adjacently, one interconnector 150 is shared by the 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 . In addition, since the fuel cell stack 100 has a pair of end plates 104 and 106, the power generation unit 102 located at the top in the fuel cell stack 100 does not have the upper interconnector 150, and is located at the bottom. The generating unit 102 does not have a lower interconnector 150 (see Figures 2 and 3). The interconnector 150 is an example of a first conductive member in the claims.

The single cell 110 includes an electrolyte layer 112, and an air electrode (cathode) 114 and a fuel electrode (anode) 116 facing each other in the Z-axis direction (the direction in which the power generation units 102 are arranged) with the electrolyte layer 112 interposed therebetween. The single cell 110 of this embodiment is a fuel electrode supporting type single cell in which the electrolyte layer 112 and the air electrode 114 are supported by the fuel electrode 116 .

The electrolyte layer 112 is a substantially rectangular plate-shaped member when viewed in the Z-axis direction, and is a dense (low porosity) layer. The Z-axis direction view here means "when viewed from a direction parallel to the Z-axis direction" (the same applies to "direction view" below). The electrolyte layer 112 is formed of a solid oxide such as YSZ (yttria-stabilized zirconia), ScSZ (scandia-stabilized zirconia), SDC (samarium-doped ceria), GDC (gadolinium-doped ceria), perovskite-type oxide, or the like. there is The air electrode 114 is a substantially rectangular plate-shaped member smaller than the electrolyte layer 112 when viewed in the Z-axis direction, and is a porous layer (having a higher porosity than the electrolyte layer 112). The air electrode 114 is made of, for example, a perovskite oxide (eg, LSCF (lanthanum strontium cobalt iron oxide), LSM (lanthanum strontium manganese oxide), LNF (lanthanum nickel iron)). The fuel electrode 116 is a substantially rectangular plate-shaped member having substantially the same size as the electrolyte layer 112 when viewed in the Z-axis 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 fuel electrode side current collector 144 is, for example, 25 to 60 vol %, and the average pore diameter of this portion is, for example, 0.5 μm to 4 μm. The single cell 110 (power generation unit 102) of this embodiment having such a configuration is a solid oxide fuel cell (SOFC) using a solid oxide as an electrolyte. In addition, the fuel electrode 116 of this embodiment is an example of a specific electrode in the claims.

The separator 120 is a frame-shaped member in which a substantially rectangular hole 121 penetrating in the Z-axis direction is formed near the center, and is made of metal, for example. The peripheral portion of the separator 120 around the hole 121 faces the peripheral portion of the surface of the electrolyte layer 112 on the air electrode 114 side. The separator 120 is joined to the electrolyte layer 112 (single cell 110) by a joint portion 124 formed of a brazing material (for example, Ag brazing material) arranged at the opposing portion. The air chamber 166 facing the air electrode 114 and the fuel chamber 176 facing the fuel electrode 116 are separated by the separator 120 to prevent gas leakage from one electrode side to the other electrode side in the peripheral portion of the unit cell 110 . Suppressed.

As shown in FIG. 6, the air electrode side frame 130 is a frame-shaped member having a substantially rectangular hole 131 formed in the vicinity of the center in the Z-axis direction, and is made of an insulator such as mica. there is A hole 131 in the cathode-side frame 130 constitutes an air chamber 166 facing the cathode 114 . The air electrode-side frame 130 is in contact with the peripheral edge portion of the surface of the separator 120 opposite to the side facing the electrolyte layer 112 and the peripheral edge portion of the surface of the interconnector 150 facing the air electrode 114 . . Also, the pair of interconnectors 150 included in the power generation unit 102 are electrically insulated by the air electrode side frame 130 . The air electrode side frame 130 also has an oxidizing gas supply communication hole 132 that communicates the oxidizing gas supply manifold 161 and the air chamber 166, and an oxidizing gas supply communication hole 132 that communicates the air chamber 166 and the oxidizing gas discharge manifold 162. A discharge communication hole 133 is formed.

As shown in FIG. 7, the anode-side frame 140 is a frame-shaped member having a substantially rectangular hole 141 extending in the Z-axis direction near its center, and is made of metal, for example. A hole 141 in the anode-side frame 140 constitutes a fuel chamber 176 facing the anode 116 . The fuel electrode-side frame 140 is in contact with the periphery of the surface of the separator 120 facing the electrolyte layer 112 and the periphery of the surface of the interconnector 150 facing the fuel electrode 116 . Further, the fuel electrode side frame 140 has 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 electrode 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 quadrangular prism-shaped current collector elements, and is made 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 electrolyte layer 112 and the surface of the interconnector 150 facing the air electrode 114 . However, as described above, the uppermost power generation unit 102 in the fuel cell stack 100 does not have the upper interconnector 150, so the air electrode side current collector 134 in the power generation unit 102 is the upper end plate 104 is in contact. Since the air electrode side current collector 134 has such a configuration, it electrically connects the air electrode 114 and the interconnector 150 (or the end plate 104). In addition, in this embodiment, the air electrode side current collector 134 and the interconnector 150 are formed as an integral member. That is, a flat plate-shaped portion orthogonal to the Z-axis direction in the integrated member functions as an interconnector 150, and a plurality of projections formed so as to protrude from the flat plate-shaped portion toward the air electrode 114 The current collector element that is the part functions 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 coating, and between the air electrode 114 and the air electrode side current collector 134, A conductive bonding layer for bonding may be interposed.

As shown in FIGS. 4 and 5, the fuel electrode side current collector 144 is arranged within the fuel chamber 176 . The fuel electrode side current collector 144 is located between the single cell 110 and the interconnector 150 .

The thermal expansion coefficient of the fuel electrode side current collector 144 is different from that of the interconnector 150 . The fuel electrode side current collector 144 is made of, for example, nickel, a nickel alloy, stainless steel, or the like. The coefficients of thermal expansion of the current collector on the fuel electrode side and the interconnector can be appropriately adjusted by considering the types of materials forming them. It can be specified by measuring using TMA8310). The fuel electrode side current collector 144 is an example of a second conductive member in the claims.

Since the fuel electrode side current collector 144 has the configuration described above, it electrically connects the fuel electrode 116 and the interconnector 150 (or the end plate 106).

The spacer 149 is covered with the fuel electrode side current collector 144 . The spacer 149 is formed in a plate shape, for example, from mica. Incidentally, the plate thickness of the spacer 149 is, for example, 0.4 to 3 mm.

A-2. Operation of fuel cell stack 100:
As shown in FIGS. 2, 4 and 6, the oxidant gas is supplied 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 oxidizing gas OG is supplied to the oxidizing gas supply manifold 161 through the branch portion 29 of the gas passage member 27 and the hole of the main body portion 28, and is supplied from the oxidizing gas supply manifold 161 to each power generation unit. The oxidant gas is supplied to the air chamber 166 via the oxidant gas supply communication hole 132 of 102 . 3, 5 and 7, the fuel gas is fed through a gas pipe (not shown) connected to the 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 branch portion 29 of the gas passage member 27 and the hole of the main body portion 28, and the fuel of each power generation unit 102 is supplied from the fuel gas supply manifold 171. The gas 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, the oxygen contained in the oxidant gas OG and the hydrogen contained in the fuel gas FG in the single cell 110 Electricity is generated by an electrochemical reaction with This power generation reaction is an exothermic reaction. In each power generation unit 102, the air electrode 114 of the single cell 110 is electrically connected to one interconnector 150 through the air electrode side current collector 134, and the fuel electrode 116 is electrically connected through the fuel electrode side current collector 144. are electrically connected to the other interconnector 150 . Also, the plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. Therefore, the electrical energy generated in each power generation unit 102 is taken out from the end plates 104 and 106 that function as output terminals of the fuel cell stack 100 . Since the SOFC generates power at a relatively high temperature (for example, 700° C. to 1000° C.), the fuel cell stack 100 is heated by the heater ( (not shown).

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. Furthermore, through the holes of the body portion 28 and the branch portion 29 of the gas passage member 27 provided at the position of the oxidizing gas discharge manifold 162, fuel is supplied through a gas pipe (not shown) connected to the branch portion 29. It is discharged outside 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. Furthermore, the fuel cell stack 100 is supplied to the fuel cell stack 100 via a gas pipe (not shown) connected to the branch portion 29 through the holes of the main body portion 28 and the branch portion 29 of the gas passage member 27 provided at the position of the fuel gas discharge manifold 172 . is discharged to the outside of the

A-3. Detailed configuration of fuel electrode side current collector 144 and its surroundings:
FIG. 8 is an explanatory view showing an enlarged XZ cross-sectional configuration of a portion (X1 portion in FIG. 4) of the single cell 110. As shown in FIG. However, FIG. 8 shows a cross section of the single cell 110 at a position where a through hole TH, which will be described later, is formed in the fuel electrode side current collector 144 . FIG. 8 shows the XZ cross-sectional configuration of the single cell 110 at the position of VIII-VIII in FIG. 10, which will be described later. FIG. 9 is an explanatory view showing an enlarged YZ cross-sectional configuration of a portion (X2 section in FIG. 5) of the unit cell 110. As shown in FIG. FIG. 10 is an explanatory diagram showing an enlarged XY cross-sectional configuration of a portion of the single cell 110 (section X3 in FIG. 7). FIG. 11 is an explanatory view showing the YZ cross-sectional configuration of the single cell 110 at the position XI-XI in FIG.

As shown in FIG. 8, the fuel electrode side current collector 144 includes an electrode side contact portion 145, an opposite side contact portion 146, a connecting portion 147 (see FIG. 4), and an X-direction tip portion 148. . The electrode-side contact portion 145 contacts the fuel electrode 116 and contacts the spacer 149 on the side opposite to the fuel electrode 116 . The opposite side contact portion 146 is in contact with the interconnector 150 (more precisely, the surface of the lower interconnector 150 of the pair of interconnectors 150). However, as described above, since the lowest power generation unit 102 in the fuel cell stack 100 does not have the lower interconnector 150, the opposite contact portion 146 of the power generation unit 102 is connected to the lower end plate. 106 is in contact. The connecting portion 147 connects the electrode side contact portion 145 and the opposite side contact portion 146 (see FIG. 4). The X-direction tip portion 148 is connected to the side of the electrode-side contact portion 145 opposite to the side connected to the connecting portion 147 (X-axis negative direction side). The spacer 149 is covered with the X-direction tip portion 148 of the fuel electrode side current collector 144 , the electrode side contact portion 145 , the connecting portion 147 and the opposite side contact portion 146 . Note that the X-direction tip portion 148 is an example of the tip portion in the claims.

As described above, the spacer 149 is arranged between the electrode-side contact portion 145 and the opposite-side contact portion 146 of the fuel electrode-side current collector 144, so that the fuel electrode-side current collector 144 is not affected by temperature cycles and reactive gases. The deformation of the power generation unit 102 due to pressure fluctuations is followed, and the electrical connection between the fuel electrode 116 and the interconnector 150 (or the end plate 106) via the fuel electrode side current collector 144 is well maintained.

As shown in FIG. 9, the anode-side current collector 144 further includes a Y-direction tip 148A and a Y-direction tip 148B. The two Y-direction tip portions 148A and 148B are respectively connected to one (negative Y-axis direction) end and the other (positive Y-axis direction) end of the electrode-side contact portion 145 in the Y-axis direction.

(Further detailed configuration of X-direction tip 148 and its periphery)
As shown in FIG. 8 (and FIG. 4), the X-direction tip portion 148 of the fuel electrode-side current collector 144 is a portion located on the opposite side of the spacer 149 to the connecting portion 147 (X-axis negative direction side). have. As shown in FIG. 8, the entire X-direction tip 148 may be located on the opposite side of the spacer 149 from the connecting portion 147 (X-axis negative direction side). may be located on the opposite side of the spacer 149 to the connecting portion 147 (X-axis negative direction side). Note that “located on the side opposite to the connecting portion 147 with respect to the spacer 149 (X-axis negative direction side)” means that the connecting portion 147 is opposite to the spacer 149 (X-axis negative direction side). and positioned so as to overlap the spacer 149 when viewed in the X-axis direction.

The X-direction tip portion 148 of the fuel electrode-side current collector 144 is a first vertically extending portion 200 that extends downward from the opposite side (X-axis negative direction side) of the electrode-side contact portion 145 to the side connected to the connecting portion 147 . and an X extension portion 201 extending in the X-axis negative direction from the lower end of the first vertical extension portion 200 .

As shown in FIG. 10, the X-direction tip 148 extends in the Y-axis direction, which is the direction along the spacer 149 (in other words, the extension direction of the spacer 149) when viewed in the Z-axis direction.

As shown in FIGS. 8 and 10, each power generation unit 102 includes a plurality of electrodes that join an X-direction tip portion 148 (more specifically, an X extension portion 201) of a fuel electrode-side current collector 144 and an interconnector 150. A junction 151 is provided. The joint portion 151 of the present embodiment is a weld mark formed by welding (for example, spot welding using a laser) the X-direction tip portion 148 of the fuel electrode side current collector 144 and the interconnector 150 . As shown in FIG. 10 , the plurality of joints 151 are arranged along the Y-axis direction while being spaced apart from each other (for example, at approximately equal intervals) when viewed in the Z-axis direction. Here, "along a certain direction" may allow an error of ±20° with respect to the direction. The Y-axis direction is an example of a specific direction in the claims. The process of welding the fuel electrode side current collector 144 and the interconnector 150 must be performed while the fuel electrode side current collector 144 and the interconnector 150 are in close contact with each other. (For example, Ni foil of about 25 μm) is not easy to adhere. Therefore, as a welding method, it is preferable to adopt spot welding, which is a method of easily bringing the fuel electrode-side current collector 144 and the interconnector 150 into close contact even when a thin material is used for the fuel electrode-side current collector 144 .

Here, an area defined as follows when viewed in the Z-axis direction is referred to as a "specific area SA". That is, as shown in FIG. 10, the specific area SA is an area surrounded by a first line segment LP1, a second line segment LP2, a third line segment LP3, and a fourth line segment LP4. The center C1 of one of the plurality of joints 151 (hereinafter referred to as “first joint 151”; for example, joint 1511 in FIG. 10) and the joint 151 (hereinafter referred to as It is referred to as the “second joint portion 151.” For example, the direction perpendicular to the imaginary straight line VL passing through the center C2 of the joint portion 1512) in FIG. The first line segment LP1 is the first line segment that intersects the contour line on the side opposite to the electrode-side contact portion 145 of the X-direction tip portion 148, of the imaginary straight line in the specific orthogonal direction (X-axis direction) that overlaps the first joint portion 151. It is an imaginary line segment connecting the first outer intersection point OI1 and the first inner intersection point II1 that intersects the surface of the spacer 149 closest to the first joint portion 151 . The second line segment LP2 is the second line segment that intersects the contour line of the X-direction tip portion 148 on the side opposite to the electrode-side contact portion 145, of the imaginary straight line in the specific orthogonal direction (X-axis direction) that overlaps the second joint portion 151. It is an imaginary line segment connecting the second outer intersection point OI2 and the second inner intersection point II2 that intersects the surface of the spacer 149 closest to the second joint 151 . The third line segment LP3 is a virtual line segment connecting the first outer intersection point OI1 and the second outer intersection point OI2. A fourth line segment LP4 is a virtual line segment connecting the first inner intersection point II1 and the second inner intersection point II2. 10, the joint portion 1511, which is one of the plurality of joint portions 151, is the first joint portion 151, and the joint portion 1512, which is the joint portion 151 located next to the joint portion 1511, is the second joint portion 151. The specific area SA when the joint portion 151 is shown. The specific orthogonal direction (X-axis direction) is an example of a second direction in the scope of claims.

As shown in FIG. 10, the X-direction tip portion 148 of the anode-side current collector 144 is missing in part of the specific region SA. More specifically, in this embodiment, the fuel electrode-side current collector 144 has a plurality of cutouts CP recessed in the X-axis direction. is missing. One notch CP is formed between two adjacent joints 151 . Note that the number of cutouts CP formed between two adjacent joints 151 may be two or more. Each notch CP faces a portion of the fuel chamber 176 that is located near the fuel electrode 116 . In the present embodiment, in the specific region SA associated with any combination of two adjacent joints 151, the X-direction tip 148 of the fuel electrode-side current collector 144 is located in one of the specific regions SA as described above. missing in some parts. In FIG. 10, the notch CP has a substantially trapezoidal shape with the upper base longer than the lower base (bottom of the recess), but the shape is not particularly limited, and may be, for example, a rectangle. may Further, the corners of the cutout portion CP may be curved instead of straight, and in this case, it may become more difficult to deform (be less likely to rise).

Let L1 be the length of the first line segment LP1 in the specific orthogonal direction (X-axis direction in this embodiment), L2 be the length of the second line segment LP2 in the specific orthogonal direction (X-axis direction), and An imaginary line segment passing through the missing portion of the X-direction tip portion 148 in a specific orthogonal direction (X-axis direction) between the segment LP1 and the second line segment LP2. Let L3 be the length of the portion of the virtual line segment connecting the line segment LP4 that overlaps the electrode-side contact portion 145 and the X-direction tip portion 148, and the length L3/length L1 is a first ratio A1, and the length L3 The first ratio A1 and the second ratio A2 are both 0.8 or less when the length L2 is the second ratio A2. The first ratio A1 and the second ratio A2 are, for example, 0.5.

(Further detailed configuration of Y-direction tip portions 148A and 148B and their surroundings)
As shown in FIG. 9, the Y-direction tip portions (148A, 148B) of the fuel electrode-side current collector 144 have portions positioned on the Y-axis direction side with respect to the spacer 149. As shown in FIG. More specifically, the Y-direction tip portion 148A connected to the Y-axis negative direction end of the electrode-side contact portion 145 of the fuel electrode-side current collector 144 is the portion located on the Y-axis negative direction side with respect to the spacer 149. have. A Y-direction tip portion 148B connected to the end in the Y-axis positive direction of the electrode-side contact portion 145 of the fuel electrode-side current collector 144 has a portion positioned on the Y-axis positive direction side with respect to the spacer 149. . As shown in FIG. 9, the entire Y-direction tip portions (148A, 148B) may be positioned on the Y-axis direction side with respect to the spacer 149. may be positioned on the Y-axis direction side with respect to the spacer 149 .

In this embodiment, the Y-direction leading end portion 148A connected to the Y-axis negative direction end of the electrode-side contact portion 145 of the fuel electrode-side current collector 144 extends from the Y-axis negative direction end of the electrode-side contact portion 145. It has a second vertically extending portion 203 extending downward, and a Y extending portion 204 extending from the lower end of the second vertically extending portion 203 in the Y-axis negative direction. The second vertical extension portion 203 and the Y extension portion 204 are located on the Y-axis negative direction side with respect to the spacer 149 . Note that "located on the Y-axis negative direction side with respect to the spacer 149" means located on the Y-axis negative direction side with respect to the spacer 149 and overlapping the spacer 149 when viewed in the Y-axis direction. means

In this embodiment, the Y-direction leading end portion 148B connected to the end of the electrode-side contact portion 145 of the fuel electrode-side current collector 144 in the positive Y-axis direction extends from the end of the electrode-side contact portion 145 in the positive Y-axis direction. A third vertically extending portion 205 extending downward and a Y extending portion 206 extending from the lower end of the third vertically extending portion 205 in the positive direction of the Y axis are provided. The third vertical extending portion 205 and the Y extending portion 206 are positioned on the Y-axis positive direction side with respect to the spacer 149 . Note that "located on the Y-axis positive direction side with respect to the spacer 149" means located on the Y-axis positive direction side with respect to the spacer 149 and overlapping the spacer 149 when viewed in the Y-axis direction. means

As shown in FIG. 9, each power generation unit 102 includes a joint portion 153 that joins a Y-direction tip portion 148A (more specifically, a Y extension portion 204) of the fuel electrode side current collector 144 and the interconnector 150; A joining portion 154 that joins the Y-direction tip portion 148B (more specifically, the Y extension portion 206) of the fuel electrode-side current collector 144 and the interconnector 150 is provided. Both the joint 153 and the joint 154 of the present embodiment are weld marks formed by welding (for example, spot welding). 7 shows the state before the Y-direction tip 148A of the fuel electrode-side current collector 144 is joined to the interconnector 150 for the sake of easy understanding of the drawing. there is

(Further detailed configuration of connecting portion 147)
As shown in FIGS. 8 and 10 , the connecting portion 147 is formed with a plurality of through holes 181 that communicate with the space on the side opposite to the spacer 149 with respect to the connecting portion 147 . Each through-hole 181 faces the single cell 110 .

As shown in FIG. 10, the plurality of through-holes 181 are arranged in the Y-axis direction at intervals.

In this embodiment, the opposite side contact portion 146, the electrode side contact portion 145, the connecting portion 147, the X direction tip portion 148, the Y direction tip portion 148A, and the Y direction tip portion 148B of the fuel electrode side current collector 144 are It is composed of an integral member.

In this embodiment, the fuel electrode side current collector 144 is formed of a metal foil (eg, 10 to 800 μm thick) made of nickel, nickel alloy, stainless steel, or the like. As shown in the partially enlarged view of FIG. 7, the fuel electrode side current collector 144 is formed by making cuts in a substantially rectangular metal foil, bending and raising a plurality of rectangular portions, and forming the cutout portions in the rectangular portions. It is manufactured by notching to form the CP.

A-4. Effect of this embodiment:
As described above, the fuel cell stack 100 in this embodiment includes a plurality of power generation units 102 arranged side by side. Each power generation unit 102 includes a single cell 110 , an interconnector 150 , an anode-side current collector 144 and a spacer 149 . The single cell 110 includes an electrolyte layer 112, and an air electrode 114 and a fuel electrode 116 facing each other in the Z-axis direction with the electrolyte layer 112 interposed therebetween. The interconnector 150 is arranged on the Z-axis direction side with respect to the single cell 110 . The fuel electrode-side current collector 144 is positioned between the unit cell 110 and the interconnector 150 (more precisely, the lower interconnector 150 of the pair of interconnectors 150; The coefficient of expansion is different from the thermal expansion coefficient of interconnect 150 . A spacer 149 is located between the single cell 110 and the interconnector 150 . The fuel electrode side current collector 144 includes an electrode side contact portion 145 , an opposite side contact portion 146 , a connecting portion 147 and an X-direction tip portion 148 . The electrode-side contact portion 145 contacts the fuel electrode 116 and contacts the spacer 149 on the side opposite to the fuel electrode 116 . Opposite contact portion 146 contacts interconnector 150 . The connecting portion 147 connects the electrode side contact portion 145 and the opposite side contact portion 146 . The X-direction tip portion 148 has a portion connected to the electrode-side contact portion 145 and located on the opposite side of the spacer 149 from the connecting portion 147 . The X-direction tip portion 148 extends in the Y-axis direction (hereinafter referred to as “specific direction Y”), which is the direction along the spacer 149 when viewed in the Z-axis direction. Each power generation unit 102 includes a plurality of joints 151 that join an X-direction tip 148 of a fuel electrode-side current collector 144 and an interconnector 150 . The plurality of joint portions 151 are arranged side by side with a space therebetween along the specific direction Y when viewed in the Z-axis direction. The X-direction leading end portion 148 is missing in part of the specific area SA.

As described above, the specific area SA is an area defined as follows when viewed in the Z-axis direction. That is, the specific area SA is an area surrounded by the first line segment LP1, the second line segment LP2, the third line segment LP3, and the fourth line segment LP4. The first line segment LP1 is one of the plurality of joints 151, which is one of the plurality of joints 151, and is one of the plurality of joints 151, which is the electrode side of the virtual straight line in the specific orthogonal direction (the X-axis direction in this embodiment). It is an imaginary line segment that connects a first outer intersection point OI1 that intersects the contour line on the side opposite to the contact portion 145 and a first inner intersection point II1 that intersects the surface of the spacer 149 closest to the first joint portion 151 . The specific orthogonal direction (X-axis direction) is an imaginary straight line VL passing through the center C1 of the first joint 151 and the center C2 of the second joint 151, which is the joint 151 located next to the first joint 151. It is the orthogonal direction. The second line segment LP2 is the second line segment that intersects the contour line of the X-direction tip portion 148 on the side opposite to the electrode-side contact portion 145, of the imaginary straight line in the specific orthogonal direction (X-axis direction) that overlaps the second joint portion 151. It is an imaginary line segment connecting the second outer intersection point OI2 and the second inner intersection point II2 that intersects the surface of the spacer 149 closest to the second joint 151 . The third line segment LP3 is a virtual line segment connecting the first outer intersection point OI1 and the second outer intersection point OI2. A fourth line segment LP4 is a virtual line segment connecting the first inner intersection point II1 and the second inner intersection point II2.

In the fuel cell stack 100 of the present embodiment, as described above, the fuel electrode-side current collector 144 has a portion located on the opposite side of the spacer 149 to the connection portion 147 (X-axis negative direction side). A directional tip 148 is provided. Therefore, it is possible to suppress the displacement of the spacer 149 in the X-axis direction. A decrease in power generation performance can be suppressed.

By the way, in the above-described conventional fuel cell stack (Japanese Patent Application Laid-Open No. 2021-022471), the length of the tip portion of the fuel electrode side current collector in the specific orthogonal direction (X-axis direction) is uniform. In other words, considering the specific area SA as described above, it can be said that the specific area SA is not deficient. Therefore, in this fuel cell stack, for example, when the temperature changes during operation, the interconnector 150 and the fuel electrode side current collector 144 (more strictly, the X direction end portion of the fuel electrode side current collector 144 is 148), the X-direction tip 148 of the fuel electrode-side current collector 144 is deformed due to the difference in thermal expansion between the The portion between the first joint portion 151 and the second joint portion 151) contacts the unit cell 110, and as a result, the unit cell 110 and the fuel chamber 176 (the portion between the unit cell 110 and the interconnector 150) come into contact with the unit cell 110. space between) may become blocked. When the space between the single cell 110 and the fuel chamber 176 is blocked in this way, the reaction gas flowing through the fuel chamber 176 (the space between the single cell 110 and the interconnector 150) is not easily circulated into the single cell 110. inhibited. Therefore, in this fuel cell stack, the flowability of the reaction gas flowing through the fuel chamber 176 into the single cell 110 is hindered, which may reduce the power generation performance of the fuel cell stack 100 .

In contrast, in the fuel cell stack 100 of the present embodiment, as described above, part of the specific area SA is missing. Therefore, due to the difference in thermal expansion between the interconnector 150 and the fuel electrode side current collector 144, the non-joint portion 152 of the X-direction tip portion 148 (the first joint portion 151 of the X-direction tip portion 148 and the part between the second joint portion 151) is deformed and the non-joint portion 152 of the X-direction tip portion 148 contacts the single cell 110, compared to the configuration in which the specific region SA is not deficient, the X Since the contact area between the non-joint portion 152 of the direction leading end portion 148 and the unit cell 110 is small, it is suppressed that the flowability of the reactant gas flowing through the fuel chamber 176 into the unit cell 110 is inhibited. Therefore, according to the fuel cell stack 100 of the present embodiment, the non-joint portion 152 of the X-direction tip portion 148 is deformed due to the difference in thermal expansion between the interconnector 150 and the fuel electrode side current collector 144, A decrease in power generation performance of the fuel cell stack 100 due to contact of the non-joint portion 152 of the X-direction tip portion 148 with the single cell 110 can be suppressed.

In the fuel cell stack 100 of this embodiment, both the first ratio A1 and the second ratio A2 are 0.8 or less. In addition, as described above, the first ratio A1 is length L3/length L1. The length L3 is a virtual line segment passing through the missing portion of the X-direction tip 148 in a specific orthogonal direction (X-axis direction) between the first line segment LP1 and the second line segment LP2, It is the length of the portion of the imaginary line segment connecting the third line segment LP3 and the fourth line segment LP4 that overlaps the electrode-side contact portion 145 and the X-direction tip portion 148 . The length L1 is the length of the first line segment LP1 in the specific orthogonal direction (X-axis direction). The second ratio A2 is length L3/length L2. The length L2 is the length of the second line segment LP2 in the specific orthogonal direction (X-axis direction).

Therefore, in the fuel cell stack 100 of the present embodiment, the contact area between the non-joint portion 152 of the X-direction end portion 148 and the unit cell 110 is particularly small, and the reaction gas flowing through the fuel chamber 176 flows into the unit cell 110. Inhibition of sexuality is particularly effectively suppressed. Therefore, according to the fuel cell stack 100 of the present embodiment, the non-joint portion of the X-direction tip portion 148 is particularly effectively 152 is deformed and the non-joint portion 152 of the X-direction tip portion 148 is brought into contact with the unit cell 110, thereby suppressing deterioration in power generation performance of the fuel cell stack 100. FIG.

In the fuel cell stack 100 of the present embodiment, the connecting portion 147 is formed with a through hole 181 that communicates with the space on the side opposite to the spacer 149 with respect to the connecting portion 147 . The through hole 181 faces the single cell 110 . Therefore, according to the fuel cell stack 100 of the present embodiment, the flowability of the reaction gas flowing through the fuel chamber 176 (the space on the side opposite to the spacer 149 with respect to the connecting portion 147) into the single cell 110 is further improved. This allows the power generation performance of the fuel cell stack 100 to be further improved.

In the fuel cell stack 100 of this embodiment, the fuel electrode side current collector 144 has a Y-direction tip portion 148A having a portion located on the Y-axis direction side with respect to the spacer 149 . Therefore, it is possible to suppress the displacement of the spacer 149 in the Y-axis direction. A decrease in power generation performance can be suppressed.

B. Variant:
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 scope of the invention. For example, the following modifications are possible.

In the above embodiment, the fuel electrode side current collector 144 in some of the power generation units 102 includes the electrode side contact portion 145, the opposite side contact portion 146, the connecting portion 147, the X direction tip portion 148, and the Y direction tip Either the portion 148A or the Y-direction tip portion 148B may be omitted. If at least one fuel electrode-side current collector 144 includes the opposite side contact portion 146, the electrode side contact portion 145, the connecting portion 147, and the X-direction tip portion 148, the fuel electrode side current collector The displacement in the X-axis direction of the spacer 149 arranged between the electrode-side contact portion 145 and the opposite-side contact portion 146 of the body 144 can be suppressed. In addition, 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 has such a configuration (opposite side contact portion 146 , an electrode-side contact portion 145, a connecting portion 147, and an X-direction tip portion 148). In addition, a power generation unit in which 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 has such a configuration. 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 .

In the above embodiment (or modified example, the same applies hereinafter), the fuel electrode side current collector 144 in all or some of the power generation units 102 does not include either or both of the Y-direction tip portion 148B and the Y-direction tip portion 148B. , may be

In the above embodiment, the spacer 149 is covered with the X-direction tip portion 148 of the fuel electrode-side current collector 144 , the electrode-side contact portion 145 , the connecting portion 147 , and the opposite side contact portion 146 . In this regard, spacers 149 may be covered in any cross-section of single cell 110 , but spacers 149 may be covered only in some cross-sections of single cell 110 . Moreover, although the spacer 149 may be covered over the entire circumference, only a portion of the spacer 149 may be covered instead of the entire circumference.

In the above embodiment, the spacer 149 covered with one anode-side current collector 144 may be composed of a plurality of divided parts.

In the above embodiment, the joints 151, 153, and 154 are weld marks formed by welding, but all or part of these are formed by a joining method other than welding (for example, mechanical joining or adhesion). can be anything.

In the above-described embodiment, the anode-side current collector 144 has a plurality of notch portions CP that are notched so as to be recessed in the X-axis direction. , part of the specific area SA may be missing due to aspects other than the notch CP. FIG. 12 is an explanatory diagram showing an enlarged XY cross-sectional configuration of a portion of the single cell 110 (the portion corresponding to the X3 portion in FIG. 7) in the modification. FIG. 13 is an explanatory diagram showing the YZ cross-sectional configuration of the power generation unit 102 at the position of XIII-XIII in FIG. For example, as shown in FIGS. 12 and 13, a through hole TH penetrating in the Z-axis direction is formed in the X-direction tip portion 148 of the fuel electrode-side current collector 144, thereby forming a part of the specific region SA. It may be assumed that it is missing in In addition, in the examples of FIGS. 12 and 13, a plurality of through holes TH are formed, and the plurality of through holes TH are arranged side by side in the Y-axis direction while being spaced apart from each other when viewed in the Z-axis direction. Three through holes TH are formed between two adjacent joints 151 . The number of through-holes TH formed between two adjacent joints 151 is not limited to three and can be varied. Each through hole TH is a part of the fuel chamber 176 and faces a portion located near the fuel electrode 116 . In the specific area SA associated with any combination of two adjacent joints 151, the X-direction tip 148 of the fuel electrode-side current collector 144 is missing in part of the specific area SA as described above. The through hole TH can be formed by, for example, press working. Although each through-hole TH has a substantially circular shape in the examples of FIGS. 12 and 13, the shape is not particularly limited, and may be, for example, an elongated hole.

In the above embodiment, the X-direction tip 148 of the fuel electrode-side current collector 144 is missing in a part of the specific region SA in any combination of the joint 151 and the joint 151 next to it. The X-direction tip 148 of the anode-side current collector 144 may be missing in a part of the specific region SA only in the combination of a part of the joint 151 and the joint 151 adjacent thereto.

In the above embodiment, the electrode-side contact portion 145 of the fuel electrode-side current collector 144 is in contact with the surface of the fuel electrode 116 opposite to the side facing the electrolyte layer 112 via a bonding material. may Further, in the above-described embodiment, even if the opposite side contact portion 146 of the fuel electrode side current collector 144 is in contact with the surface of the interconnector 150 on the side facing the fuel electrode 116 via a bonding material, good.

In the above embodiment, the opposite side contact portion 146 of the fuel electrode side current collector 144, the electrode side contact portion 145, the connecting portion 147, and the X-direction tip portion 148 are configured by an integral member. Any or all of the contact portion 146, the electrode-side contact portion 145, and the connecting portion 147 may be configured by separate members.

In the fuel cell stack 100 of the above embodiment, the interconnector 150 (hereinafter referred to as the interconnector 150) in which the air electrode side current collector 134 is arranged on the upper side (one side in the Z-axis direction) of the unit cell 110 ), the electrode-side contact portion that contacts the air electrode 114, and the opposite-side contact portion and the electrode-side contact portion. and an X-axis direction tip connected to the side of the electrode-side contact portion opposite to the side connected to the connection portion (hereinafter referred to as “air electrode side X-axis direction tip”). , 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 opposite side contact portion and the electrode side contact portion. A configuration in which the tip in the axial direction is missing in a part of the specific area SA may be adopted. In this configuration as well, for the same reason as in the above embodiment, the presence of the X-axis direction tip portion on the air electrode side can suppress the positional deviation of the spacer 149 in the X-axis direction. of the fuel cell stack 100 caused by the non-joint portion of the X-axis direction tip of the air electrode side coming into contact with the single cell 110 due to the lack of the X-axis direction tip of the fuel cell stack 100 in a part of the specific area SA. A decrease in power generation performance can be suppressed. In this configuration, the upper interconnector 150 is an example of the first conductive member in the claims, the air electrode side current collector 134 is an example of the second conductive member in the claims, and the air electrode side current collector 134 is an example of the second conductive member in the claims. The pole 114 is an example of a specific electrode in the claims. In addition to such a configuration, in the fuel cell stack 100 of the above-described embodiment, the air electrode side current collector 134 is connected to the end of the electrode side contact portion 145 in the Y-axis direction. At least a part of which is provided with a Y-axis direction tip portion located on the Y-axis direction side of the air electrode side spacer (hereinafter referred to as "Y-axis direction tip portion on the air electrode side") is adopted. may be In this configuration as well, for the same reason as in the above embodiment, the presence of the Y-axis direction tip portion on the air electrode side makes it possible to suppress the displacement of the air electrode side spacer in the Y axis direction.

Further, in the above embodiments, SOFCs that generate electricity by utilizing the electrochemical reaction between the hydrogen contained in the fuel gas and the oxygen contained in the oxidant gas are used. It is also applicable to an electrolytic cell unit, which is the minimum unit of a solid oxide electrolysis cell (SOEC) that utilizes hydrogen to generate hydrogen, and an electrolytic cell stack comprising a plurality of electrolytic cell units. The configuration of the electrolysis cell stack is known, for example, as described in Japanese Patent Laid-Open No. 2016-81813. Configuration. That is, the fuel cell stack 100 in the above-described embodiment should be read as an electrolysis cell stack, and the power generation unit 102 should be read as an electrolysis cell unit.

22 (22A to 22E): Bolt 24: Nut 26: Insulating sheet 27: Gas passage member 28: Body portion 29: Branch portion 100: Fuel cell stack 102: Power generation unit 104, 106: End plate 108: Communication hole 110: Single Cell 112: Electrolyte layer 114: Air electrode 116: Fuel electrode 120: Separator 121: Hole 124: Joint 130: Air electrode side frame 131: Hole 132: Oxidant gas supply passage 133: Oxidant gas discharge passage 134: Air electrode side current collector 140: fuel electrode side frame 141: hole 142: fuel gas supply communication hole 143: fuel gas discharge communication hole 144: fuel electrode side current collector 145: electrode side contact portion 146: opposite side contact portion 147 : connecting part 148: X-direction tip part 148A, 148B: Y-direction tip part 149: Spacer 150: Interconnector 151, 153, 154: Joint part 152: Non-joint part 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 181: Through hole 200: First vertical extension 201: X extension 203: Second vertical extension 204: Y extension Part 205: Third vertical extension 206: Y extension 1511: Joint 1512: Joint CP: Notch FG: Fuel gas FOG: Fuel off-gas II1: First inner intersection II2: Second inner intersection OG: Oxidation OI1: first outer intersection point OI2: second outer intersection point OOG: oxidant off-gas SA: specific area TH: through hole

Claims (3)

a single cell including an electrolyte layer, and an air electrode and a fuel electrode facing each other in a first direction with the electrolyte layer interposed therebetween;
a first conductive member arranged on the first direction side with respect to the unit cell;
a second conductive member positioned between the single cell and the first conductive member and having a coefficient of thermal expansion different from that of the first conductive member;
An electrochemical reaction cell stack in which a plurality of electrochemical reaction units are arranged side by side, each comprising a spacer positioned between the single cell and the first conductive member,
The second conductive member in the specific reaction unit, which is at least one of the electrochemical reaction units,
an electrode-side contact portion that contacts a specific electrode that is one of the air electrode and the fuel electrode and that contacts the spacer on a side opposite to the specific electrode;
an opposite side contact portion that contacts the first conductive member;
a connecting portion that connects the electrode-side contact portion and the opposite-side contact portion;
A tip portion connected to the electrode-side contact portion and having a portion located on the side opposite to the connecting portion with respect to the spacer, the tip portion extending in a specific direction along the spacer when viewed in the first direction. an electrochemical reaction cell stack comprising:
The specific reaction unit is a plurality of joints that join the tip of the second conductive member and the first conductive member, and is spaced apart from each other along the specific direction when viewed in the first direction. Equipped with multiple joints that are lined up while being vacant,
any one of the plurality of joints is defined as a first joint, and the joint located adjacent to the first joint is defined as a second joint; and
When viewed from the first direction, a direction orthogonal to an imaginary straight line passing through the center of the first joint and the center of the second joint is defined as a second direction, and the second joint overlapping the first joint is defined as a second direction. Of the imaginary straight lines in the direction, a first outer intersection point that intersects the contour line on the side opposite to the electrode-side contact portion of the tip portion, and a first inner intersection point that intersects the surface of the spacer closest to the first joint portion. An imaginary line segment connecting the points of intersection is defined as a first line segment, and among imaginary straight lines in the second direction overlapping the second joint portion, the virtual line segment intersects the contour line on the opposite side of the electrode-side contact portion of the tip portion. and a second inner intersection point that intersects the surface of the spacer closest to the second joint portion is defined as a second line segment, and the first outer intersection point and the second outer intersection point A virtual line segment connecting the first inner intersection point and the second inner intersection point is a fourth line segment, and the first line segment, the second line segment and the When the region surrounded by the third line segment and the fourth line segment is defined as the specific region,
The tip is missing in a part of the specific region,
An electrochemical reaction cell stack characterized by: The electrochemical reaction cell stack according to claim 1,
The length of the first line segment in the second direction is L1, the length of the second line segment in the second direction is L2, and the distance between the first line segment and the second line segment is in the virtual line segment passing through the missing portion of the tip portion in the second direction, the virtual line segment connecting the third line segment and the fourth line segment in the electrode side contact When the length of the portion and the portion overlapping with the tip portion is L3, the length L3/length L1 is a first ratio A1, and the length L3/length L2 is a second ratio A2,
Both the first ratio A1 and the second ratio A2 are 0.8 or less,
An electrochemical reaction cell stack characterized by: The electrochemical reaction cell stack according to claim 1 or claim 2,
A through hole communicating with a space on the opposite side of the connecting portion to the spacer and facing the single cell is formed in the connecting portion,
An electrochemical reaction cell stack characterized by:

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