JP7222000B2 - Electrochemical reaction cell stack and method for manufacturing electrochemical reaction cell stack - Google Patents

Description

The technology disclosed by this specification relates to an electrochemical reaction cell stack and a method for manufacturing 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 stacks (hereinafter referred to as "power generation blocks") 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"). (for example, Patent Document 1). 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 first direction with the electrolyte layer interposed therebetween. A single cell has a portion (hereinafter referred to as a “power generating portion”) where the electrolyte layer, the air electrode, and the fuel electrode overlap in the first direction.

The power generation unit further has a current collecting member and a joint. The current collecting member is arranged on the side opposite to the electrolyte layer in the first direction with respect to one of the air electrode and the fuel electrode (hereinafter referred to as the "specific electrode"), and is electrically connected to the specific electrode. . The joint portion is a conductive member positioned between the single cell and the current collecting member in the first direction and joining the single cell and the current collecting member.

The fuel cell stack described above is manufactured through the following preparation steps and pressurization steps. The preparing step prepares a composite including a plurality of pre-bonded power generation units arranged side by side in a first direction. The pre-bonded power generation unit includes a single cell, a current collecting member disposed on the side opposite to the electrolyte layer in the first direction with respect to a specific electrode (one of the air electrode and the anode), and A member comprising a pre-bonding joint positioned between a unit cell and a current collecting member. The pre-joining joint is a member that becomes a joint and contains a conductive material.

In the pressurizing step, the joint is formed by pressurizing the composite in the first direction. The manufacture of the fuel cell stack is completed through the preparation process and pressurization process described above.

JP 2020-9744 A

In the conventional fuel cell described above, for example, in the step of forming the specific electrode (one of the air electrode and the fuel electrode) by a method such as screen printing, the thickness of the specific electrode (thickness in the first direction, hereinafter the same) ) may occur. For example, a plurality of single cells manufactured under the same manufacturing conditions (for example, a plurality of single cells included in the same lot) have approximately the same variation in thickness. When screen printing is used, the thickness of the single cell generally increases from the film formation start side toward the film formation end side in the film formation direction. Due to such variations in the thickness of the specific electrode, variations in the thickness of the composite may occur. In that case, there is a risk that the single cell will crack due to the concentration of the pressure applied to a relatively thick portion of the composite during the pressure step.

Such problems are also common to electrolytic cell stacks, which are a form of solid oxide type electrolytic cells (hereinafter referred to as "SOEC") that generate hydrogen using the electrolysis reaction of water. It is an issue. In this specification, the fuel cell stack and the electrolysis cell stack are collectively referred to as "electrochemical reaction cell stack".

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

The technology disclosed in this specification can be implemented, for example, in the following forms.

(1) An electrochemical reaction stack disclosed in the present specification is 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 single cell having a power generation portion in which the electrolyte layer, the air electrode, and the fuel electrode overlap in a first direction, and a specific electrode, which is one of the air electrode and the fuel electrode, in the first direction. a current collecting member disposed on the side opposite to the electrolyte layer and electrically connected to the specific electrode; and a conductive joint that joins the current collecting member, the electrochemical reaction stack comprising a plurality of electrochemical reaction units arranged side by side in the first direction, wherein Visually, a rectangular imaginary area that includes all the power generation units included in the plurality of electrochemical reaction units, and each side of the rectangle corresponds to one of the power generation units of the plurality of electrochemical reaction units Each region of 3 rows and 3 columns obtained by vertically and horizontally dividing each of the adjacent virtual regions into three is defined as a divided region, and the divided region located in the i-th row and the j-th column is defined as a divided region (i, j) (i= 1, 2, 3, j = 1, 2, 3), and in each power generation unit, among the portions located in each of the eight divided regions excluding the divided region (2, 2), the first is defined as the thickest divided region, the position of the thickest divided region in at least one specific single cell is the specific single cell is different from the position of the thickest divided region in at least one of the single cells other than

In a configuration in which the positions of the thickest divided regions in all the single cells included in the plurality of electrochemical reaction units are the same (hereinafter referred to as “comparative configuration 1”), the electrochemical reaction When the pressure is concentrated on the portion of the cell stack that is located in the thickest divided region when viewed from the first direction, cracking of the single cell is particularly likely to occur.

On the other hand, in the present electrochemical reaction stack, as described above, the position of the thickest divided region in the specific single cell which is at least one single cell is the thickest divided region in at least one single cell other than the specific single cell. is different from the position of Therefore, in the electrochemical reaction stack of the present invention, in comparison with the comparative configuration 1, the portion of the electrochemical reaction cell stack located in the thickest divided region when viewed in the first direction is added. Concentration of pressure is suppressed. Therefore, according to the present electrochemical reaction stack, it is possible to suppress the cracking of the single cells due to the concentration of the applied pressure on a part of the electrochemical reaction cell stack (the part located in the thickest divided region). .

(2) In the electrochemical reaction stack, a group composed of the divided region (1,1), the divided region (2,1), and the divided region (3,1) is defined as a first group, and the divided region (1) , 3), the divided region (2, 3), and the divided region (3, 3) are defined as a second group, the plurality of unit cells included in the plurality of electrochemical reaction units is a first single cell which is the single cell having any of the divided regions included in the first group as the thickest divided region, and any of the divided regions included in the second group and a second single cell which is the single cell having the thickest divided region.

The first group and the second group face each other across the center point of the virtual area when viewed from the first direction. It can be said that the thickest divided regions of the single cell are evenly distributed in the circumferential direction of the first straight line (virtual straight line in the first direction passing through the center point of the virtual region). In this electrochemical reaction stack, the thickest divided regions of the first unit cell and the second unit cell are evenly dispersed in the circumferential direction of the first straight line, so that the electrochemical reaction cell The circumferential positions of the first straight lines of the thicker portion of the stack are also evenly distributed. Therefore, according to the present electrochemical reaction stack, cracking of the single cells due to the concentration of the applied pressure on a part of the electrochemical reaction cell stack (the part located in the thickest divided region) can be effectively prevented. can be suppressed.

(3) In the above electrochemical reaction stack, the second single cell rotates about a straight line in the first direction that passes through the center point of the imaginary region as the axis of rotation. is rotated by 180 degrees, and the thickest divided area is the single cell. In other words, the first single cell has the thickest divided region located at a position obtained by rotating the thickest divided region in the first single cell by 0° (or 360°) about the first straight line. It is used as a divided area. In the present electrochemical reaction stack, the positions of the thickest divided regions of the first unit cell and the second unit cell are evenly distributed in the circumferential direction of the first straight line. The circumferential positions of the first straight lines in the relatively thick portions of the reaction cell stack are also evenly distributed. Therefore, according to the present electrochemical reaction stack, cracking of the single cells caused by the concentration of the applied pressure on a part of the electrochemical reaction cell stack (the part located in the thickest divided region) can be effectively prevented. can be suppressed.

(4) In the above electrochemical reaction stack, when viewed in the first direction, the power generating section of the first single cell and the power generating section of the second single cell have outer edges aligned. It is good also as a structure which is a rectangle of the same size. According to this electrochemical reaction stack, the positions of the thickest divided regions are evenly dispersed in the circumferential direction of the first straight line as described above, and the first single cell, The shapes of the second single cells can match each other.

(5) In the electrochemical reaction stack, a group composed of the divided region (1,1), the divided region (1,2), and the divided region (1,3) is defined as a third group, and the divided region (3 , 1), the divided region (3, 2), and the divided region (3, 3) as a fourth group, the plurality of unit cells included in the plurality of electrochemical reaction units further includes a third single cell which is the single cell having any of the divided regions included in the third group as the thickest divided region; and a fourth unit cell which is the unit cell having the division region as the thickest division region. The third group and the fourth group face each other across the center point of the virtual region when viewed from the first direction, and the facing direction is the same as the facing direction of the first group and the second group. are perpendicular to each other, so that the thickest divided regions of the first unit cells, . I can say. In this electrochemical reaction stack, the thickest divided regions of the first unit cells, . The circumferential positions of the first straight lines of the relatively thick portion of the chemical reaction cell stack are also particularly evenly distributed. Therefore, according to the present electrochemical reaction stack, cracking of the single cells due to the concentration of the applied pressure on a part of the electrochemical reaction cell stack (the part located in the thickest divided region) can be effectively prevented. can be suppressed.

(6) In the above electrochemical reaction stack, the third unit cell rotates about the straight line in the first direction passing through the center point of the imaginary area as the axis of rotation, and rotates the thickest divided area in the first unit cell. is rotated by 90°, the thickest divided area is the single cell, and the fourth single cell is a straight line in the first direction passing through the center point of the virtual area. may be used as the axis of rotation, and the thickest divided region in the first unit cell may be the thickest divided region located at a position obtained by rotating the thickest divided region by 270°. In the present electrochemical reaction stack, the thickest divided regions of the first unit cells, . The circumferential positions of the first straight lines of the relatively thick portion of the chemical reaction cell stack are also particularly evenly distributed. Therefore, according to the present electrochemical reaction stack, cracking of the single cell due to concentration of pressure on a portion of the electrochemical reaction cell stack (portion located in the thickest divided region) during manufacturing is prevented. , can be suppressed more effectively.

(7) In the above electrochemical reaction stack, the first single cell, the second single cell, and the third single cell included in the plurality of single cells included in the plurality of electrochemical reaction units The cell and the fourth unit cell are arranged in the order of the first unit cell, the third unit cell, the second unit cell, and the fourth unit cell in the first direction. , and adjacent to each other. According to the present electrochemical reaction stack, by arranging the plurality of single cells while rotating them by 90°, the above-mentioned "first direction, first single cell (0°), third A configuration in which the unit cells 110 (90°), the second unit cells 110 (180°), and the fourth unit cells 110 (270°) are arranged in this order can be easily realized (manufactured).

(8) In the above electrochemical reaction stack, when viewed from the first direction, the power generation unit of the first unit cell, the power generation unit of the second unit cell, and the power generation unit of the third unit cell Both the power generation section and the power generation section of the fourth unit cell may be configured to have the same size rectangles with aligned outer edges. According to this electrochemical reaction stack, as described above, the thickest divided regions are evenly distributed in the circumferential direction of the first straight line, and the first unit cells, . . . The shapes of the fourth single cells can match each other.

(9) In the electrochemical reaction stack, the average thickness in the first direction among the portions located in each of the eight divided regions excluding the divided region (2, 2) in each of the single cells is the thinnest divided region, the position of the thickest divided region in the specific single cell is the thinnest divided region in at least one of the single cells other than the specific single cell The configuration may be the same as the position of the area.

In a configuration in which the positions of the thickest divided regions in all the single cells included in the plurality of electrochemical reaction units are different from the thinnest divided regions (hereinafter referred to as “comparative configuration 2”), the above-described When the applied pressure is concentrated on the portion of the electrochemical reaction cell stack that is located in the thickest divided region when viewed from the first direction, cracking of the single cell is particularly likely to occur.

On the other hand, in the present electrochemical reaction stack, as described above, the position of the thickest divided region in the specific single cell, which is at least one single cell, is the thinnest divided region in at least one single cell other than the specific single cell. is the same as the position of Therefore, in the electrochemical reaction stack of the present invention, in comparison with the comparative configuration 2, the portion of the electrochemical reaction cell stack that is located in the thickest divided region when viewed in the first direction is added. Concentration of pressure is suppressed. Therefore, according to the present electrochemical reaction stack, cracking of the single cells caused by the concentration of the applied pressure on a part of the electrochemical reaction cell stack (the part located in the thickest divided region) can be effectively suppressed. can be suppressed.

(10) A method for manufacturing an electrochemical reaction cell stack disclosed in the present specification includes 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 current collecting member disposed on a side opposite to the electrolyte layer in the first direction with respect to a specific electrode, which is one of the air electrode and the fuel electrode, and electrically connected to the specific electrode; a conductive joint located between the single cell and the current collecting member in the first direction and joining the single cell and the current collecting member, respectively; In the method for manufacturing an electrochemical reaction stack including a plurality of electrochemical reaction units arranged side by side, the material to be the specific electrode is wet-formed in a film formation direction orthogonal to the first direction to form the specific electrode. a first step of forming a plurality of electrodes; the single cell having the specific electrode; the collector member disposed on the side opposite to the electrolyte layer in the first direction with respect to the specific electrode; a pre-bonding electrochemical reaction unit having a pre-bonding junction that is a member that serves as a bonding portion and is positioned between the single cell in the first direction and the current collecting member; A composite comprising a plurality of the electrochemical reaction units, wherein the plurality of pre-bonding electrochemical reaction units are arranged side by side in the first direction, and the film formation direction in the specific unit cell, which is at least one of the unit cells, is a second step of fabricating a composite having a film formation direction different from the film formation direction in at least one of the unit cells other than the specific unit cell; and a third step of forming. According to this manufacturing method, it is possible to suppress the cracking of the single cell due to the concentration of the pressure force on a part of the composite (the part located in the thickest divided region) in the third step.

In the method for manufacturing an electrochemical reaction stack described above, the second step includes forming the plurality of unit cells included in the plurality of electrochemical reaction units into first unit cells and first straight lines extending in the first direction. is the rotation axis, the second single cell is the single cell whose film formation direction is the direction obtained by rotating the film formation direction of the first single cell by 180°, and the first straight line is the rotation axis. As a third unit cell whose film formation direction is the direction obtained by rotating the film formation direction of the first unit cell by 90°, and the first straight line as a rotation axis, the and a fourth unit cell that is the unit cell whose film formation direction is the direction obtained by rotating the film formation direction of the first unit cell by 270°. may be According to this manufacturing method, by rotating and arranging the plurality of single cells by 90°, the above-mentioned "first direction, first single cell (0°), third single cell 110 (90°), the second unit cell 110 (180°), and the fourth unit cell (270°) arranged in this order can be easily realized (manufactured).

1 is a perspective view showing the external configuration of a fuel cell stack 100 according to this embodiment; FIG. Explanatory diagram showing the XZ cross-sectional configuration of the fuel cell stack 100 at the position II-II in FIG. Explanatory drawing showing the YZ cross-sectional configuration of the fuel cell stack 100 at the position III-III in FIG. 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. 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. Schematic diagram for explaining the configuration of each power generation unit 102 provided in the fuel cell stack 100 shown in FIG. Flowchart showing a method for manufacturing the fuel cell stack 100 of the present embodiment Explanatory diagrams showing a method of manufacturing the fuel cell stack 100 of the present embodiment. Explanatory diagrams showing a method of manufacturing the fuel cell stack 100 of the present embodiment.

A. This 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 Z-axis direction is referred to as the upward direction, and the negative Z-axis direction is referred to as the downward direction. may be installed. The same applies to FIG. 4 and subsequent figures. The same applies to the method of manufacturing the fuel cell stack 100 described later (in particular, the mounting direction of the composite 109 in the composite manufacturing step S13 and the joint forming step S14 described later).

The fuel cell stack 100 includes a plurality of (seven in this embodiment) fuel cell power generating units (hereinafter simply referred to as "power generating units") 102, a pair of terminal plates 70 and 80, and a pair of insulating sheets 92 and 96. and a pair of end plates 104,106. The seven power generation units 102 are arranged side by side in a predetermined arrangement direction (vertical direction in this embodiment). The arrangement direction (vertical direction) corresponds to the first direction in the claims.

One of the pair of terminal plates 70 and 80 (hereinafter referred to as "upper terminal plate 70") is mounted above an assembly (hereinafter referred to as "power generation block 103") composed of seven power generation units 102. One of the pair of insulating sheets 92 and 96 (hereinafter referred to as the "upper insulating sheet 92") is arranged above the upper terminal plate 70, and the pair of end plates 104 and 106 One of them (hereinafter referred to as the “upper end plate 104 ”) is arranged above the upper insulating sheet 92 . The other of the pair of terminal plates 70 and 80 (hereinafter referred to as the "lower terminal plate 80") is arranged below the power generation block 103 and is one of the pair of insulating sheets 92 and 96. The other (hereinafter referred to as the "lower insulating sheet 96") is arranged below the lower terminal plate 80 and is the other of the pair of end plates 104, 106 (hereinafter referred to as the "lower end plate 106"). ”) are arranged on the lower side of the lower insulating sheet 96 . More specifically, between the upper terminal plate 70 and the upper insulating sheet 92, a cover separator 60, which will be described later, is interposed. As is clear from the above description, the upper end plate 104 and the lower end plate 106 are positioned on both sides of the power generation block 103 in the Z-axis direction.

Each layer (power generation unit 102, terminal plates 70, 80, end plates 104, 106) constituting the fuel cell stack 100 has a plurality of (eight in this embodiment) penetrating in the vertical direction on the outer peripheral portion around the Z-axis direction. ) holes are formed, and corresponding holes formed in each layer communicate with each other in the vertical direction to form a communication hole 108 extending vertically from the upper end plate 104 to the lower end plate 106 . In the following description, the holes formed in each layer of the fuel cell stack 100 to form the communication holes 108 may also be referred to as the communication holes 108 .

A vertically extending bolt 22 is inserted through each communication hole 108 , and the fuel cell stack 100 is fastened by a vertical compressive force of the bolt 22 and a nut 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 upper end plate 104 and on the other side (lower side) of the bolt 22 ) and the lower surface of the lower end plate 106, an insulating sheet 26 is interposed. However, at locations where gas passage members 27 to be described later are provided, gas passage members 27 and gas passage members 27 are arranged between the nut 24 and the surface of the lower end plate 106, and on the upper and lower sides of the gas passage members 27, respectively. An insulating sheet 26 is interposed. The insulating sheet 26 is made of, for example, a mica sheet, a ceramic fiber sheet, a ceramic powder sheet, a glass sheet, a glass-ceramic composite, or the like.

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 bolt 22 (bolt 22A) positioned thereon and the communication hole 108 through 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. Functioning as an oxidant gas supply manifold 161, which is a gas flow path for supplying to the power generation unit 102, 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) located near the point and the communication hole 108 through 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.

Also, 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 through 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 through 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 . The hole of the branch portion 29 communicates with the hole of the 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 oxidant gas supply manifold 161 communicates with the oxidant 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 plate-like members having a substantially rectangular outer shape when viewed from the top and bottom, and are made of a conductive material such as stainless steel. Holes 32 and 34 are formed in the vicinity of the centers of the pair of end plates 104 and 106, respectively. When viewed from the top and bottom, the inner peripheral lines of the holes 32, 34 formed in the pair of end plates 104, 106 respectively include the unit cells 110, which will be described later. Therefore, the vertical compressive force of each bolt 22 and nut 24 acts mainly on the outer peripheral portion of each power generation unit 102 (the portion on the outer peripheral side of each unit cell 110 described later).

(Structure of insulating sheets 92 and 96)
The pair of insulating sheets 92 and 96 is a plate-like member having a substantially rectangular outer shape when viewed in the vertical direction, and is made of, for example, a mica sheet, a ceramic fiber sheet, a ceramic powder sheet, a glass sheet, a glass-ceramic composite, or the like. made of flexible materials. A hole 94 is formed near the center of the upper insulating sheet 92 so as to communicate with the hole 32 of the upper end plate 104 and penetrate vertically. When viewed from above, the inner peripheral line of the hole 94 formed in the upper insulating sheet 92 encloses each unit cell 110, which will be described later. In the present embodiment, the inner peripheral line of the hole 94 formed in the upper insulating sheet 92 substantially matches the inner peripheral line of the hole 32 formed in the upper end plate 104 when viewed in the vertical direction.

(Configuration of Terminal Plates 70, 80)
The pair of terminal plates 70 and 80 are plate-like members having a substantially rectangular outer shape when viewed from the top and bottom, and are made of a conductive material such as stainless steel. A vertically penetrating hole 71 is formed near the center of the upper terminal plate 70 . As viewed from above, the inner peripheral line of the hole 71 formed in the upper terminal plate 70 includes each unit cell 110, which will be described later. In this embodiment, the inner circumference of the hole 71 formed in the upper terminal plate 70 substantially coincides with the inner circumference of the hole 32 formed in the upper end plate 104 when viewed from above. The upper terminal plate 70 has a projecting portion 78 projecting outward from the outer peripheral line of the upper end plate 104 as viewed in the vertical direction, and the projecting portion 78 functions as a plus side output terminal of the fuel cell stack 100. . In addition, the lower terminal plate 80 has a protrusion 88 that protrudes outward from the outer peripheral line of the lower end plate 106 when viewed in the vertical direction. Functions as a terminal.

(Configuration of power generation unit 102)
FIG. 4 is an explanatory diagram showing the XZ cross-sectional configuration of two power generation units 102 adjacent to each other (two power generation units 102 located at the top) at the same position as the cross section shown in FIG. 2, and FIG. 3 is an explanatory diagram showing the YZ cross-sectional configuration of two power generation units 102 adjacent to each other (two power generation units 102 positioned at the top) at the same position as the cross section shown in FIG.

As shown in FIGS. 4 and 5, the power generation unit 102 includes a fuel cell single cell (hereinafter referred to as "single cell") 110, a single cell separator 120, an air electrode side frame 130, and a fuel electrode side frame. 140 , a fuel electrode-side current collecting member 148 , and a pair of current collecting members 190 and a pair of IC separators 180 constituting the uppermost layer and the lowermost layer of the power generation unit 102 . The single cell separator 120, the air electrode side frame 130, the fuel electrode side frame 140, and the IC separator 180 are formed with holes corresponding to the communication holes 108 through which the bolts 22 are inserted in the outer peripheral portions around the Z-axis direction. It is

The single cell 110 includes an electrolyte layer 112 , a cathode 114 positioned above the electrolyte layer 112 , an anode 116 positioned below the electrolyte layer 112 , and between the electrolyte layer 112 and the cathode 114 . and an intermediate layer 118 disposed thereon. The single cell 110 of this embodiment is a fuel electrode supporting type single cell in which the fuel electrode 116 supports the other layers (the electrolyte layer 112, the air electrode 114, and the intermediate layer 118) constituting the single cell 110. FIG. The single cell 110 has a portion (hereinafter referred to as “power generating portion”) PG where the electrolyte layer 112, the air electrode 114, and the fuel electrode 116 overlap in the vertical direction.

The electrolyte layer 112 is a substantially rectangular plate-shaped member when viewed from above, and is configured to contain a solid oxide (for example, YSZ (yttria-stabilized zirconia)). That is, the single cell 110 of this embodiment is a solid oxide fuel cell (SOFC) using a solid oxide as an electrolyte. The air electrode 114 is a substantially rectangular plate-shaped member smaller than the electrolyte layer 112 when viewed from above, and is configured to contain, for example, a perovskite oxide (for example, LSCF (lanthanum strontium cobalt iron oxide)). The fuel electrode 116 is a substantially rectangular plate-shaped member having substantially the same size as the electrolyte layer 112 when viewed from above, and is formed of, for example, Ni (nickel), a cermet made of Ni and ceramic particles, a Ni-based alloy, or the like. there is The intermediate layer 118 is a substantially rectangular plate-shaped member having substantially the same size as the air electrode 114 when viewed from above, and is configured to contain, for example, GDC (gadolinium-doped ceria) and YSZ. The intermediate layer 118 is formed so that an element (eg, Sr) diffused from the air electrode 114 reacts with an element (eg, Zr) contained in the electrolyte layer 112 to generate a high-resistance substance (eg, SrZrO ₃ ). It has a suppressing function. In addition, in this embodiment, the air electrode 114 corresponds to the specific electrode in the claims.

The single-cell separator 120 is a frame-shaped member having a substantially rectangular hole 121 (hereinafter referred to as "first separator through-hole 121") penetrating vertically in the vicinity of the center thereof. made of a conductive material. The single cell separator 120 has a substantially plate shape. A portion 122 surrounding the first separator through-hole 121 in the single-cell separator 120 (hereinafter referred to as “first separator inner peripheral portion 122”) is the surface of the electrolyte layer 112 on the air electrode 114 side (upper side). It faces the outer periphery. The single cell separator 120 is joined to the electrolyte layer 112 (single cell 110) by a joining portion 124 formed of a brazing material (for example, Ag brazing) arranged at the opposing portion. The first separator inner peripheral portion 122 (the portion surrounding the first separator through-hole 121 of the single cell separator 120) includes the electrolyte layer 112 and the collector member 190 (in the upper specific power generation unit 102X described later, the uppermost collector). 190X). In this embodiment, the outer peripheral portion of the single-cell separator 120 is joined to the upper surface of the fuel electrode-side frame 140 by laser welding, for example.

The single-cell separator 120 includes an inner portion 126 including the first separator inner peripheral portion 122, an outer portion 127 located outside the inner portion 126, and a connecting portion 128 connecting the inner portion 126 and the outer portion 127. and In this embodiment, the inner portion 126 and the outer portion 127 are generally flat plates extending in a direction generally perpendicular to the vertical direction. Moreover, the connecting portion 128 has a curved shape that protrudes downward from both the inner portion 126 and the outer portion 127 . A lower side (fuel chamber 176 side) portion of the connecting portion 128 is a convex portion, and an upper side (air chamber 166 side) portion of the connecting portion 128 is a concave portion.

A glass sealing portion 125 containing glass is arranged in the vicinity of the first separator through hole 121 in the single cell separator 120 . The glass seal portion 125 is located on the air chamber 166 side with respect to the joint portion 124, and the surface of the first separator inner peripheral portion 122 of the single cell separator 120 and the single cell 110 (in this embodiment, the electrolyte layer 112). The glass seal portion 125 effectively suppresses gas leak (cross leak) from one electrode side to the other electrode side in the outer peripheral portion of the unit cell 110 .

The current collecting member 190 is a conductive member having a substantially rectangular flat plate-shaped flat plate portion 150 and a plurality of substantially columnar air electrode side current collecting portions 134 protruding from the flat plate portion 150 toward the air electrode 114, It is made of metal (for example, ferritic stainless steel). The flat plate portion 150 is arranged so as to overlap the hole 71 of the upper terminal plate 70 when viewed in the vertical direction. In this embodiment, a conductive coating layer 194 made of spinel oxide, for example, is formed on the surface of the current collecting member 190 (the surface facing the air chamber 166). Hereinafter, the current collecting member 190 covered with the coating layer 194 is simply referred to as the current collecting member 190 . The current collecting member 190 (more specifically, each air electrode side current collecting portion 134 of the current collecting member 190) is connected to the air electrode of the single cell 110 via a conductive bonding material 196 made of, for example, a spinel oxide. 114. In addition, on the surface of the current collecting member 190 (the surface facing the fuel chamber 176 or the upper specific space 58 described later), a contaminant (for example, Cr (chromium)) from the current collecting member 190 is prevented from being released or diffused. Therefore, a specific treatment (eg, annealing treatment) may be performed. The current collecting members 190 (excluding the topmost current collecting member 190X, which will be described later) ensure electrical continuity between the power generation units 102 and prevent mixing of reaction gases between the power generation units 102 . In this embodiment, when two power generation units 102 are arranged adjacent to each other, one current collecting member 190 is shared by the two adjacent power generation units 102 . That is, the upper collector member 190 in a given power generation unit 102 is the same member as the lower collector member 190 in another power generation unit 102 adjacent to the upper side of the power generation unit 102 . In addition, the lower current collecting member 190 of the power generating unit 102 located at the lowest position in the fuel cell stack 100 is electrically connected to the lower terminal plate 80 via a conductive bonding material 196 . In addition, the current collecting member 190 (hereinafter also referred to as the "uppermost current collecting member 190X") above the power generation unit 102 (hereinafter also referred to as the "upper specific power generation unit 102X") located at the uppermost position in the fuel cell stack 100. ) is connected to the upper terminal plate via an IC separator 180 (hereinafter also referred to as a “top IC separator 180X”) and/or other members (connection member 48, cover member 50, cover separator 60) described later. 70 is electrically connected. That is, the upper terminal plate 70 is electrically connected to the power generation block 103 . Note that the uppermost collector member 190X is arranged below the upper terminal plate 70 . As is clear from the above description, it can be said that the current collecting member 190 is arranged above the air electrode 114 and is electrically connected to the air electrode 114 . This "upper side" is, in other words, "the side opposite to the electrolyte layer 112 in the vertical direction". Moreover, the current collecting member 190 referred to here is, more strictly speaking, the upper current collecting member 190 in a certain power generation unit 102 .

The IC separator 180 is a frame-like member having a substantially rectangular second separator through-hole 181 vertically penetrating near the center thereof, and is made of a conductive material such as metal. The IC separator 180 has a substantially plate shape. In this embodiment, the portion 182 surrounding the second separator through-hole 181 (hereinafter referred to as the “second separator inner peripheral portion 182”) of the IC separator 180 is the outer periphery of the current collecting member 190 (the flat plate portion 150). It is joined to the upper surface of the part, for example by laser welding. The IC separator 180 separates an air chamber 166 facing the air electrode 114 in one power generation unit 102 and a fuel chamber 176 facing the fuel electrode 116 in another power generation unit 102 adjacent to the power generation unit 102, Gas leak (cross leak) from one electrode side to the other electrode side in the outer peripheral portion of the current collecting member 190 is suppressed. Further, in this embodiment, the outer peripheral portion of the IC separator 180 is joined to the lower surface of the fuel electrode side frame 140 by, for example, laser welding. Among the pair of IC separators 180 included in a power generation unit 102, the upper IC separator 180 is connected to the air chamber 166 of the power generation unit 102 and the other power generation unit 102 adjacent to the power generation unit 102 on the upper side. and the fuel chamber 176 of the . Also, of the pair of IC separators 180 included in a certain power generation unit 102, the lower IC separator 180 is adjacent to the fuel chamber 176 of the power generation unit 102 and the power generation unit 102 on the lower side. and the air chamber 166 of the power generation unit 102 . Thus, the IC separator 180 suppresses gas leakage between the power generation units 102 in the outer periphery of the power generation units 102 .

Like the other IC separators 180, the uppermost IC separator 180X is a frame-shaped member having a substantially rectangular second separator through-hole 181X penetrating in the vertical direction near the center. formed. Further, in this embodiment, the portion surrounding the second separator through hole 181X of the uppermost IC separator 180X is joined to the upper surface of the outer peripheral portion of the uppermost current collecting member 190X by laser welding, for example. Further, in this embodiment, the outer peripheral portion of the uppermost IC separator 180X is joined to the lower surface of the upper terminal plate 70 by laser welding, for example.

The IC separator 180 has an inner portion 186 including a second separator inner peripheral portion (a portion surrounding the second separator through-hole 181) 182 of the IC separator 180, and an outer portion 187 located on the outer peripheral side of the inner portion 186. and a connecting portion 188 that connects the inner portion 186 and the outer portion 187 . In this embodiment, the inner portion 186 and the outer portion 187 are generally flat plates extending in a direction generally perpendicular to the vertical direction. Further, the connecting portion 188 has a curved shape that protrudes downward from both the inner portion 186 and the outer portion 187 .

The air electrode side frame 130 is a frame-shaped member having a substantially rectangular hole 131 penetrating vertically in the vicinity of the center thereof, and is made of an insulator such as mica, for example. A hole 131 in the cathode-side frame 130 constitutes an air chamber 166 facing the cathode 114 . The air-electrode-side frame 130 includes the outer peripheral portion of the surface of the single-cell separator 120 opposite to the electrolyte layer 112 (upper side) and the side (lower side) of the upper IC separator 180 facing the air chamber 166 . side), and functions as a sealing member that secures the gas-sealing property therebetween (that is, the gas-sealing property of the air chamber 166). Also, the cathode-side frame 130 electrically insulates between the pair of IC separators 180 included in the power generation unit 102 (that is, between the pair of collector members 190). 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.

The fuel electrode-side frame 140 is a frame-shaped member having a substantially rectangular hole 141 extending vertically through the vicinity of the center thereof, 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 formed on the outer periphery of the surface of the single cell separator 120 on the side (lower side) facing the electrolyte layer 112 and on the side (upper side) of the IC separator 180 on the lower side facing the fuel chamber 176 . It is in contact with the perimeter of the surface. 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 fuel electrode side collector member 148 is arranged in the fuel chamber 176 . The fuel electrode side collector member 148 has a conductive portion 144 and an elastic portion 149 . The conductive portion 144 is a portion that electrically connects the fuel electrode 116 and the collector member 190, and is made of, for example, nickel, a nickel alloy, stainless steel, or the like. The conductive portion 144 includes an electrode facing portion 145 in contact with the lower surface of the fuel electrode 116, an interconnector facing portion 146 in contact with the upper surface of the collector member 190, and an electrode facing portion 145 and the interconnector facing portion. 146, and a connecting portion 147 that connects with 146. In addition, the elastic portion 149 is a portion for ensuring elasticity of the fuel electrode side collector member 148, and is formed of, for example, mica. The interconnector-facing portion 146 of the conductive portion 144 is arranged vertically between the collector member 190 and the elastic portion 149 , and the electrode-facing portion 145 of the conductive portion 144 is positioned vertically above the fuel electrode. 116 and the elastic portion 149 . As a result, the fuel electrode side current collecting member 148 follows the deformation of the power generation unit 102 due to temperature cycles and reaction gas pressure fluctuations, and the fuel electrode 116 and the current collecting member 190 are electrically connected via the fuel electrode side current collecting member 148 . Good connection is maintained.

(Configuration near top of fuel cell stack 100)

As shown in FIGS. 4 and 5, the fuel cell stack 100 of this embodiment includes a cover member 50 and a cover separator 60 arranged above the uppermost power generation unit 102 (upper specific power generation unit 102X). Prepare. The cover member 50 is a substantially rectangular plate-shaped member when viewed from the top and bottom, and is made of a conductive material (for example, metal). In addition, the surface of the cover member 50 (the surface facing the upper specific space 58 described later) is subjected to a specific treatment in order to suppress the release and diffusion of contaminants (for example, Cr (chromium)) from the cover member 50. (For example, annealing treatment) may be performed. The cover member 50 is arranged within a hole 71 formed in the upper terminal plate 70 . In addition, the cover member 50 is vertically separated from and adjacent to the upper collector member 190 (top collector member 190X) included in the upper specific power generation unit 102X. That is, a space (a space formed by the holes 71 of the upper terminal plate 70, hereinafter referred to as an "upper specific space 58") is formed between the cover member 50 and the uppermost collector member 190X. ing. The upper specific space 58 is positioned above the plurality of unit cells 110 (all unit cells 110) included in the fuel cell stack 100. As shown in FIG.

The cover separator 60 is a frame-like member having a substantially rectangular hole (hereinafter referred to as a "third separator through hole") 61 extending vertically through the vicinity of the center thereof. It is made of a conductive material. In this embodiment, the portion of the cover separator 60 surrounding the third separator through-hole 61 is joined to the upper surface of the outer peripheral portion of the cover member 50 by laser welding, for example. Further, the outer peripheral portion of the cover separator 60 is joined to the upper surface of the upper terminal plate 70 by laser welding, for example. The upper specific space 58 is defined by the cover separator 60 (and the uppermost IC separator 180X joined to the uppermost collector member 190X).

The cover separator 60 has an inner portion 66 including a portion surrounding the third separator through-hole 61 of the cover separator 60, an outer portion 67 located outside the inner portion 66, and an inner portion 66. and a connecting portion 68 that connects the outer portion 67 with the outer portion 67 . In this embodiment, the inner portion 66 and the outer portion 67 are generally flat plates extending in a direction generally perpendicular to the vertical direction. Further, the connecting portion 68 has a curved shape that protrudes downward from both the inner portion 66 and the outer portion 67 .

Moreover, as shown in FIGS. 4 and 5, the fuel cell stack 100 of the present embodiment further includes a connection member 48 arranged in the upper specific space 58 . In this embodiment, the connection member 48 has the same configuration as the fuel electrode side collector member 148 . That is, the connection member 48 has the conductive portion 44 and the elastic portion 49 . The conductive portion 44 is a portion that electrically connects the cover member 50 and the uppermost collector member 190X, and is made of, for example, nickel, nickel alloy, stainless steel, or the like. The conductive portion 44 includes a cover member facing portion 45 in contact with the lower surface of the cover member 50, an interconnector facing portion 46 in contact with the upper surface of the uppermost collector member 190X, and a cover member facing portion 45. It has a connecting portion 47 that connects with the interconnector facing portion 46 . Also, the elastic portion 49 is a portion for ensuring elasticity of the connecting member 48, and is formed of, for example, mica. The interconnector facing portion 46 of the conductive portion 44 is arranged between the uppermost collector member 190X and the elastic portion 49 in the vertical direction, and the cover member facing portion 45 of the conductive portion 44 is arranged in the vertical direction. is arranged between the cover member 50 and the elastic portion 49 at the .

The fuel cell stack 100 of this embodiment has an upper terminal unit 270 near its top. Upper terminal unit 270 has a terminal structure described below. That is, the upper terminal unit 270 is arranged above the power generation block 103, and includes the upper terminal plate 70, the uppermost collector member 190X, the cover member 50, the connection member 48, and the uppermost IC separator. 180X and a separator 60 for cover. As mentioned above, upper terminal plate 70 is electrically connected to generator block 103 . Therefore, the upper terminal unit 270 including the upper terminal plate 70 is also electrically connected to the power generation block 103 . In the upper terminal unit 270, the upper terminal plate 70 is joined to the uppermost IC separator 180X and the cover separator 60 by laser welding, as described above. In other words, the upper terminal plate 70 is electrically connected to both. In the upper terminal unit 270 , the cover separator 60 is arranged on the uppermost side, and the upper insulating sheet 92 is arranged above the cover separator 60 . Also, the uppermost IC separator 180X separates the upper specific space 58 from the air chamber 166 of the upper specific power generation unit 102X.

A-2. Operation of fuel cell stack 100:
As shown in FIGS. 2 and 4, the oxidant gas OG 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. Then, the oxidizing gas OG is supplied to the oxidizing gas supply manifold 161 via the branch portion 29 of the gas passage member 27 and the hole of the main body portion 28, and the oxidizing gas OG is supplied from the oxidizing gas supply manifold 161 to each power generation unit 102. The agent gas is supplied to the air chamber 166 through the agent gas supply communication hole 132 . 3 and 5, the fuel gas FG 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 fuel gas supply manifold 171. Then, the fuel gas FG is supplied to the fuel gas supply manifold 171 via the branch portion 29 of the gas passage member 27 and the hole of the main body portion 28, and the fuel gas supply communication of each power generation unit 102 from the fuel gas supply manifold 171. It is supplied to fuel chamber 176 through 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, electric power is generated in the single cell 110 by the electrochemical reaction of the oxidant gas OG and the fuel gas FG. will be 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 the current collecting member 190 via the conductive bonding material 196, and the fuel electrode 116 is electrically connected to the current collecting member 190 via the fuel electrode side current collecting member 148. 190 is electrically connected. That is, the plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. Also, in the fuel cell stack 100, the upper current collecting member 190 (the uppermost current collecting member 190X) of the uppermost power generation unit 102 (the upper specific power generation unit 102X) is electrically connected to the upper terminal plate 70. The lower current collecting member 190 of the lowermost power generation unit 102 is electrically connected to the lower terminal plate 80 . Therefore, the electrical energy generated in each power generation unit 102 is taken out from the pair of terminal plates 70 , 80 functioning 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).

As shown in FIGS. 2 and 4, 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 and further oxidized. 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 agent gas discharge manifold 162 . is discharged to the outside of the 3 and 5, 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, and further fuel gas Through the holes in the body portion 28 and the branch portion 29 of the gas passage member 27 provided at the position of the exhaust manifold 172, the gas is supplied to the outside of the fuel cell stack 100 via a gas pipe (not shown) connected to the branch portion 29. Ejected.

A-3. Further detailed configuration of each power generating unit 102:
FIG. 6 is a schematic diagram for explaining the configuration of each power generation unit 102 provided in the fuel cell stack 100 shown in FIG. On the left side of FIG. 6, among the plurality of (seven in this embodiment) power generation units 102 (hereinafter referred to as "the plurality of power generation units 102") provided in the fuel cell stack 100, the power generation unit 102 is located at the bottom. Four (power generation units 102A, . . . , power generation units 102D, which will be described later) are shown. In FIG. 6, for the sake of convenience, the relative positions of the power generation units 102A, . ) are displaced.

Hereinafter, the power generation units 102 are referred to as "power generation unit 102A", "power generation unit 102B", ..., "power generation unit 102G" in order from the lowest power generation unit 102. The unit cells 110 provided in the power generation unit 102A are referred to as "single cells 110A", and the single cells 110 provided in the power generation unit 102B are referred to as "single cells 110B". Similarly, the unit cells 110 provided in the power generation units 102C, . The single cell 110A corresponds to the first single cell in the claims, the single cell 110C corresponds to the second single cell in the claims, and the single cell 110B corresponds to the third single cell in the claims. It corresponds to a single cell, and the single cell 110D corresponds to the fourth single cell in the claims.

The plurality of power generation units 102 (102A, . . . , 102G) are vertically adjacent to each other. Each power generation unit 102 is rectangular with the same dimensions when viewed in the vertical direction. It should be noted that the term "same size" as used herein may allow an error of up to ±3 mm (the same shall apply hereinafter).

The seven unit cells 110 (110A, . ing.

The power generation portion PG of each unit cell 110 (the portion of the unit cell 110 where the electrolyte layer 112, the air electrode 114, and the fuel electrode 116 overlap in the vertical direction) is the same size with the outer edges aligned when viewed in the vertical direction. is a rectangle of It should be noted that the phrase "the outer edges are aligned" may allow an error of up to ±3 mm (the same shall apply hereinafter).

In FIG. 6, the dashed-dotted line frame described above each power generation unit 102 indicates the virtual area VA. The virtual area VA is a rectangular area that includes all the power generation units PG included in the plurality of power generation units 102 when viewed in the vertical direction. In this embodiment, each side of the rectangle is in contact with all the power generation units PG of the plurality of power generation units 102 . Therefore, it can be said that each side of the rectangle is in contact with one of the power generation units PG of the plurality of power generation units 102 .

Each single cell 110 is a single cell (for example, a single cell included in the same lot) manufactured under the same manufacturing conditions (especially, the air electrode 114 is formed by a manufacturing method (screen printing) described later). be. Therefore, the shape of each unit cell 110 is substantially the same, and the thickness variation (distribution) within each unit cell 110 is also substantially the same. More specifically, each single cell 110 satisfies conditions (1) to (4) described later.

In the present embodiment, markings (eg1, . . . , eg4) are engraved on each unit cell 110 (illustration of the markings of the power generation units 102E, . The contents of the markings (eg1, . . . , eg4) are identification numbers for identifying each single cell 110 manufactured under the same manufacturing conditions (for example, each single cell 110 included in the same lot). The marks (eg1, . It is located at the edge of the direction perpendicular to the film formation)). Therefore, based on the positions of the markings (eg1, .

(Power generation units 102A, ..., 102D)
The power generation units 102A, . . . , 102D will be further described. In the following, each region of 3 rows and 3 columns obtained by vertically and horizontally dividing the virtual region VA into three equal parts is referred to as a divided region SA. , j) (i=1,2,3, j=1,2,3). In each power generation unit PG (more specifically, the entire power generation unit PG included in each power generation unit 102), among the portions located in each of the eight divided areas SA excluding the divided area SA(2,2) , and the divided area SA overlapping with the portion having the largest average thickness at in the vertical direction (Z-axis direction) (hereinafter simply referred to as "average thickness at") is referred to as "thickest divided area SAmax". The “average thickness at” here means, for example, the entire target portion of the power generation unit PG (the portion of the power generation unit PG located in a certain divided area SA) in each of the X-axis direction and the Y-axis direction. It is the average of measured values of thickness in the vertical direction (Z-axis direction) at 5 mm pitches (the same applies hereinafter). Further, in each power generation unit PG, among the portions located in each of the eight divided regions SA excluding the divided region SA (2, 2), the divided region SA that overlaps the portion with the smallest average thickness at is the “maximum It is referred to as "thin segmented area SAmin".

"(thickest)" in FIG. 6 indicates the "thickest divided area SAmax", and "(thinest)" indicates the "thinnest divided area SAmin". An arrow df in FIG. 6 indicates the direction of film formation when the air electrode 114 is formed by wet film formation in the manufacturing method of the fuel cell stack 100, which will be described later. Hereinafter, this film formation direction will be referred to as "film formation direction df", and the direction perpendicular to film formation direction df as viewed from above and below will be referred to as "film formation orthogonal direction".

As described above, the single cells 110A, . . . , 110D provided in the power generation units 102A, .
Condition (1):
The closer the position of the divided area SA is to the terminal side in the film formation direction df, the thicker the average thickness at of the portion of the unit cell 110 located in the divided area SA.
Condition (2):
Of the three divided areas SA located closest to the end in the film formation direction df, the divided area SA located in the center in the direction perpendicular to the film formation is the thickest divided area SAmax.
Condition (3):
(certain one) divided area SA located in the center in the film-forming orthogonal direction is the same in the film-forming direction df, and compared with the two divided areas SA located at both ends in the film-forming orthogonal direction, The average thickness at of the portion of the unit cell 110 located in the divided area SA is thick. In other words, the two divided areas SA located at the same position in the film formation direction df and located at both ends in the film formation orthogonal direction have the same position in the film formation direction df and are located at the center of the film formation orthogonal direction. The average thickness at of the portion of the unit cell 110 located in the divided area SA is thinner than the divided area SA located in .
Condition (4):
Of the three divided areas SA located closest to the ends in the direction perpendicular to the film formation (more precisely, one of the directions perpendicular to the film formation), the divided area SA located in the center of the film formation direction df is the thinnest division. area SAmin.

Specifically, the film formation direction df, the thickest divided area SAmax, and the thinnest divided area SAmin of each single cell 110 (110A, . . . , 110D) are as follows. For the single cell 110A, the film formation direction df is the positive Y-axis direction, the thickest divided area SAmax is the divided area SA(2,3), and the thinnest divided area SAmin is the divided area SA(3,2). be.

For the single cell 110B, the film formation direction df is the negative direction of the X axis, the thickest divided area SAmax is the divided area SA(3,2), and the thinnest divided area SAmin is the divided area SA(2,1). be. In other words, when the vertical virtual straight line passing through the center point C of the virtual area VA is defined as the first straight line L1, the single cell 110B is divided into the maximum thickness divisions in the single cell 110A with the first straight line L1 as the axis of rotation. It can be said that the single cell 110 has the thickest divided area SAmax as the divided area SA located at a position where the area SAmax is rotated by 90°. Note that "90°" as used herein may allow an error of up to ±5° (the same applies to other angles referred to below).

For the single cell 110C, the film formation direction df is the Y-axis negative direction, the thickest divided area SAmax is the divided area SA(2,1), and the thinnest divided area SAmin is the divided area SA(1,2). be. In other words, in the single cell 110C, the thickest divided area SAmax is the divided area SA located at a position where the thickest divided area SAmax in the single cell 110A is rotated 180° about the first straight line L1 as the rotation axis. It can be said that it is 110.

For the single cell 110D, the film formation direction df is the positive direction of the X-axis, the thickest divided area SAmax is the divided area SA(1,2), and the thinnest divided area SAmin is the divided area SA(2,3). be. In other words, in the unit cell 110C, the thickest divided area SAmax is the divided area SA located at a position where the thickest divided area SAmax in the single cell 110A is rotated 270° about the first straight line L1 as the rotation axis. It can be said that it is 110.

As is clear from the above description, the position of the thickest divided area SAmax in the specific single cell that is at least one single cell 110 is the same as the position of the thickest divided area SAmax in at least one single cell 110 other than the specific single cell. It can be said that they are different. For example, when the single cell 110A is the specific single cell, the position of the thickest divided region SAmax in the specific single cell is the position of the thickest divided region SAmax in the three single cells 110B, . . . , 110D other than the specific single cell. different.

Further, it can be said that the position of the thickest divided area SAmax in the specific single cell is the same as the position of the thinnest divided area SAmin in at least one single cell 110 other than the specific single cell. For example, when the single cell 110A is the specific single cell, the position of the thickest divided region SAmax in the specific single cell is the position of the thinnest divided region SAmin in the single cell 110D, which is at least one single cell 110 other than the specific single cell. Same as position.

A first group G1 is defined as a group composed of the divided area SA(1,1), the divided area SA(2,1), and the divided area SA(3,1). , divided area SA(2,3) and divided area SA(3,3) is defined as a second group G2, the plurality of unit cells 110 included in the plurality of power generation units 102 are , a single cell 110C that is a single cell 110 having a maximum thickness divided region SAmax (a divided region SA in a portion where the average thickness at in the vertical direction is the largest) is any of the divided regions SA included in the first group G1; It can be said that the second group G2 includes the single cell 110A which is the single cell 110 having the thickest divided area SAmax in any of the divided areas SA included in the second group G2.

Also, a group composed of divided area SA(1,1), divided area SA(1,2), and divided area SA(1,3) is defined as a third group G3, and divided area SA(3,1) , divided area SA(3,2), and divided area SA(3,3) as a fourth group G4, the plurality of unit cells 110 included in the plurality of power generation units 102 are , a single cell 110D which is a single cell 110 having a maximum thickness divided area SAmax of any divided area SA included in the third group G3, and a single cell 110D having a maximum thickness of any divided area SA included in the fourth group G4. It can be said that it includes a single cell 110B that is the single cell 110 that is the divided area SAmax.

(Power generation units 102E, ..., 102G)
The power generation units 102E, . . . , 102G will be further described. As described above, the unit cells 110E, . . . , 110G provided in the power generation units 102E, .

Specifically, the film formation direction df, the thickest divided area SAmax, and the thinnest divided area SAmin of each unit cell 110 (102E, . . . , 102G) are as follows. For the single cell 110E, the film formation direction df is the positive Y-axis direction, the thickest divided area SAmax is the divided area SA(2,3), and the thinnest divided area SAmin is the divided area SA(3,2). be. In other words, in the single cell 110E, the film formation direction df is the same as the film formation direction df in the single cell 110A, and the divided area SA located at the same location as the thickest divided area SAmax in the single cell 110A is the thickest. It can be said that the single cell 110 is the divided area SAmax.

For the single cell 110F, the film formation direction df is the negative direction of the X axis, the thickest divided area SAmax is the divided area SA(3,2), and the thinnest divided area SAmin is the divided area SA(2,1). be. In other words, the single cell 110B rotates about the first straight line L1 (vertical straight line passing through the center point C of the virtual area VA) as the axis of rotation, and the thickest divided area SAmax in the single cell 110E (and the single cell 110A). can be said to be the single cell 110 having the thickest divided area SAmax in the divided area SA located at a position rotated by 90°.

For the single cell 110G, the film formation direction df is the Y-axis negative direction, the thickest divided area SAmax is the divided area SA(2,1), and the thinnest divided area SAmin is the divided area SA(1,2). be. In other words, the single cell 110G divides the thickest divided area SA located at a position obtained by rotating the thickest divided area SAmax in the single cell 110E (and the single cell 110A) by 180° about the first straight line L1. It can be said that the single cell 110 is the area SAmax.

A-4. Manufacturing method of fuel cell stack 100:
FIG. 7 is a flow chart showing a method for manufacturing the fuel cell stack 100 of this embodiment. 8 and 9 are explanatory diagrams showing the method of manufacturing the fuel cell stack 100 of this embodiment. A method for manufacturing the fuel cell stack 100 of the present embodiment is, for example, as follows. In the following, only the unique parts in the manufacturing method of the present embodiment will be described in detail, and for the other parts, for example, the method described in Japanese Patent Application Laid-Open No. 2018-133224 may be adopted. detailed description is omitted.

(Formation of Laminate of Electrolyte Layer 112, Fuel Electrode 116, and Intermediate Layer 118)
As shown in FIG. 8, first, a laminate of electrolyte layer 112, fuel electrode 116, and intermediate layer 118 is formed (S11 in FIG. 7).

(Formation of air electrode 114)
Next, as shown in FIG. 8, a material (for example, paste) (hereinafter referred to as "air electrode material") for forming the air electrode 114 is wet-film-formed in a predetermined film-forming direction df to form the air electrode 114. are formed (as many as the number of power generation units 102 provided in the fuel cell stack 100. In this embodiment, seven are formed (S12 in FIG. 7).

Specifically, the air electrode material is applied to the surface of the intermediate layer 118 in the laminate of the electrolyte layer 112, the fuel electrode 116, and the intermediate layer 118 by screen printing (wet film formation in the film formation direction df). , drying, and then firing to form the air electrode 114 . A single cell 110 is thus obtained. A plurality of such single cells 110 are manufactured. In a plurality of unit cells 110 manufactured under the same manufacturing conditions in this way, the variation (distribution) of the thickness in each unit cell 110 is substantially the same. Specifically, the above conditions (1) to ( 4) is satisfied. Hereinafter, the process of S12 is called electrode formation process S12. The electrode forming step S12 corresponds to the first step in the claims.

(Preparation of complex 109)
Next, as shown in FIG. 9, a member (hereinafter referred to as “joining A complex 109 having a plurality of power generation units 107 (as many as the power generation units 102 provided in the fuel cell stack 100; seven in the present embodiment) is fabricated (S13 in FIG. 7). The collector member 190 is arranged on the side opposite to the electrolyte layer 112 in the vertical direction with respect to the air electrode 114 . Here, as an example of the pre-bonding portion 139, in addition to the material containing Mn listed above as the constituent material of the bonding portion 138, a thermoplastic material (for example, resin, glass, etc.) for ensuring flexibility is included. We are hiring what we do. The pre-bonding bonding portion 139 is positioned between the unit cell 110 and the collector member 190 in the vertical direction. The plurality of pre-joining power generation units 107 are arranged side by side in the vertical direction. The pre-joining power generation unit 107 corresponds to the pre-joining electrochemical reaction unit in the claims. Hereinafter, the step of S13 is referred to as a composite production step S13. The composite production step S13 corresponds to the second step in the scope of claims.

Specifically, the unit cells 110 are arranged like the above unit cells 110A, . . . , 110G (see FIG. 6). That is, for the single cell 110A, the film formation direction df is the positive Y-axis direction, the thickest divided area SAmax is the divided area SA(2,3), and the thinnest divided area SAmin is the divided area SA(3,2 ). For the single cell 110B, the film formation direction df is the negative direction of the X axis, the thickest divided area SAmax is the divided area SA(3,2), and the thinnest divided area SAmin is the divided area SA(2,1). be. For the single cell 110C, the film formation direction df is the Y-axis negative direction, the thickest divided area SAmax is the divided area SA(2,1), and the thinnest divided area SAmin is the divided area SA(1,2). be. For the single cell 110D, the film formation direction df is the positive direction of the X axis, the thickest divided area SAmax is the divided area SA(1,2), and the thinnest divided area SAmin is the divided area SA(2,3). be. For the single cell 110E, the film formation direction df is the positive Y-axis direction, the thickest divided area SAmax is the divided area SA(2,3), and the thinnest divided area SAmin is the divided area SA(3,2). be. For the single cell 110F, the film formation direction df is the negative direction of the X axis, the thickest divided area SAmax is the divided area SA(3,2), and the thinnest divided area SAmin is the divided area SA(2,1). be. For the single cell 110G, the film formation direction df is the Y-axis negative direction, the thickest divided area SAmax is the divided area SA(2,1), and the thinnest divided area SAmin is the divided area SA(1,2). be. At this time, it can be said that the film formation direction df in the specific single cell which is at least one single cell 110 is different from the film formation direction df in at least one single cell 110 other than the specific single cell.

A method of arranging each unit cell 110 like the unit cells 110A, . . . , 110G described above is as follows, for example. First, the lowermost single cell 110A is arranged. Subsequently, on the single cell 110A, the film formation direction df is rotated with respect to the film formation direction df of the single cell 110A with a first straight line L1 (vertical straight line passing through the center point C of the virtual area VA). , the single cell 110B is arranged in a direction rotated by 90°. At this time, it can be said that the unit cell 110B is the unit cell 110 whose film formation direction df is the direction obtained by rotating the film formation direction df of the unit cell 110A by 90° with the first straight line L1 as the rotation axis. Subsequently, on the unit cell 110B, the unit cell 110C whose film formation direction df is rotated by 90° from the film formation direction df of the unit cell 110B about the first straight line L1 is arranged. At this time, it can be said that the film formation direction df of the single cell 110C is obtained by rotating the film formation direction df of the single cell 110A by 180° with the first straight line L1 as the rotation axis. Subsequently, on the unit cell 110C, the unit cell 110D whose film formation direction df is rotated by 90° from the film formation direction df of the unit cell 110C about the first straight line L1 is arranged. At this time, it can be said that the film formation direction df of the single cell 110D is obtained by rotating the film formation direction df of the single cell 110A by 270° with the first straight line L1 as the rotation axis. Similarly, the unit cells 110E, . Note that the outer edges of the unit cells 110 are aligned when viewed in the vertical direction. As described above, a configuration in which the unit cells 110 are arranged like the unit cells 110A, . . . , 110G described above can be easily realized.

Next, the composite 109 is fastened by inserting the bolt 22 into the communication hole 108 formed in each member and fitting the nut 24 on both sides of the bolt 22 . The composite 109 is produced as described above. Hereinafter, the member formed by fastening the composite 109 with the bolt 22 and the nut 24 may simply be referred to as the "composite 109".

(Formation of joint portion 138)
Next, by applying pressure to the composite 109 in the vertical direction, the joint 138 is formed (S14 in FIG. 7).

Specifically, the composite 109 is placed on a workbench in a firing furnace (electric furnace), and the portion of the composite 109 that overlaps the single cell 110 in a vertical view (in other words, the bolt 22 and the nut 24 The portion on the side that is not directly fastened) is pressed from above with a jig. As a result, the air electrode 114 and the air electrode side current collector 134 are brought into a state of being in close contact with the pre-bonding joint 139 by applying a vertical compressive load to the relevant portion of the composite 109 . In this way, the pre-bonding bonding portion 139 is fired while the air electrode 114 and the air electrode-side current collector 134 are in close contact with the pre-bonding bonding portion 139 . As a result, the pre-bonding bonding portion 139 (mainly the conductive material) is heated and cured to form a bonding portion 138 . Hereinafter, the step of S14 will be referred to as a joint forming step S14. The junction forming step S14 corresponds to the third step in the claims.

(Remaining process)
Next, by performing the remaining steps such as assembly (S15 in FIG. 7), the manufacture of the fuel cell stack 100 having the configuration described above is completed.

A-5. Effect of this embodiment:
As described above, the fuel cell stack 100 of the present embodiment includes a plurality of power generation units 102 arranged side by side in the vertical direction (Z-axis direction) (hereinafter, the plurality of power generation units 102 will be referred to as "the plurality of power generation units 102 ). The power generation unit 102 has a single cell 110 , a current collecting member 190 and a junction 138 . The unit cell 110 includes an electrolyte layer 112, and an air electrode 114 and a fuel electrode 116 that face each other in the vertical direction with the electrolyte layer 112 interposed therebetween. The single cell 110 has a power generation section PG in which an electrolyte layer 112, an air electrode 114, and a fuel electrode 116 are stacked vertically. The current collecting member 190 is arranged above the air electrode 114 (on the side opposite to the electrolyte layer 112 in the vertical direction) and electrically connected to the air electrode 114 . The joint 138 is a conductive member. The joint portion 138 is positioned between the unit cell 110 and the collector member 190 in the vertical direction, and joins the unit cell 110 and the collector member 190 . The position of the thickest divided region SAmax in the specific single cell which is at least one single cell 110 is different from the position of the thickest divided region SAmax in at least one single cell 110 other than the specific single cell. A rectangular imaginary area VA that includes all the power generation units PG included in the plurality of power generation units 102 when viewed from above and below, and each side of the rectangle corresponds to one of the power generation units PG of the plurality of power generation units 102. Each of the 3 rows and 3 columns obtained by equally dividing the virtual area VA in contact with the ) (i = 1, 2, 3, j = 1, 2, 3), the thickest divided area SAmax is divided into eight divisions excluding the divided area SA (2, 2) in each power generation unit PG. Among the portions located in each of the regions SA, the divided region SA overlaps with the portion having the largest average thickness at in the vertical direction (Z-axis direction).

In a configuration in which the positions of the thickest divided regions SAmax are the same in all the unit cells 110 included in the plurality of power generation units 102 (hereinafter referred to as “comparative configuration 1”), joint formation is performed during manufacturing. In step S14, the unit cell 110 is particularly prone to cracking due to the concentration of the applied pressure on the portion of the composite 109 located in the thickest divided area SAmax when viewed from the top-bottom direction.

On the other hand, in the fuel cell stack 100 of the present embodiment, as described above, the position of the thickest divided area SAmax in at least one specific single cell 110 is located in at least one single cell other than the specific single cell. It is different from the position of the thickest divided area SAmax in 110 . Therefore, in the fuel cell stack 100 of the present embodiment, in comparison with the above-described comparative configuration 1, in the joint formation step S14, the thickest divided region SAmax in the composite 109 in the vertical direction has Concentration of the applied pressure on the positioned portion is suppressed. Therefore, according to the fuel cell stack 100 of the present embodiment, in the joint forming step S14, the single cell 110 caused by the concentration of the pressure force on a part of the composite 109 (the part located in the thickest divided area SAmax). cracking can be suppressed.

Further, in the fuel cell stack 100 of the present embodiment, the plurality of unit cells 110 included in the plurality of power generation units 102 have any of the divided areas SA included in the first group G1 as the thickest divided area SAmax. It includes a single cell 110C, which is the single cell 110, and a single cell 110A, which is the single cell 110 whose thickest divided region SAmax is any of the divided regions SA included in the second group G2. The first group G1 is a group composed of the divided area SA(1,1), the divided area SA(2,1), and the divided area SA(3,1). The second group G2 is a group composed of the divided area SA(1,3), the divided area SA(2,3), and the divided area SA(3,3). The first group G1 and the second group G2 are opposed to each other across the center point C of the virtual area VA when viewed from above and below. It can be said that the thickest divided areas SAmax of the single cells 110A and 110B are evenly distributed in the circumferential direction of the first straight line L1 (vertical virtual straight line passing through the center point C of the virtual area VA). In the fuel cell stack 100 of the present embodiment, the thickest divided regions SAmax of the single cells 110A and 110C are evenly distributed in the circumferential direction of the first straight line L1. The circumferential positions of the first straight line L1 in the relatively thick portion are also distributed evenly. Therefore, according to the fuel cell stack 100 of the present embodiment, in the joint forming step S14, the single cell 110 caused by the concentration of the pressure force on a part of the composite 109 (the part located in the thickest divided area SAmax). cracking can be more effectively suppressed.

In addition, in the fuel cell stack 100 of the present embodiment, the single cell 110C has the first straight line L1 (vertical virtual straight line passing through the center point C of the virtual area VA) as the axis of rotation. The divided area SA located at a position obtained by rotating SAmax by 180° is set as the thickest divided area SAmax. In other words, the single cell 110A divides the thickest divided area SA located at a position where the thickest divided area SAmax in the single cell 110A is rotated by 0° (or 360°) about the first straight line L1 as the rotation axis. The area is assumed to be SAmax. In the fuel cell stack 100 of the present embodiment, the thickest divided regions SAmax of the single cells 110A and 110B are evenly dispersed in the circumferential direction of the first straight line L1, so that the composite 109 The circumferential positions of the first straight line L1 in the relatively thick portion are also distributed evenly. Therefore, according to the fuel cell stack 100 of the present embodiment, in the joint forming step S14, the single cell 110 caused by the concentration of the pressure force on a part of the composite 109 (the part located in the thickest divided area SAmax). cracking can be more effectively suppressed.

In addition, in the fuel cell stack 100 of the present embodiment, the power generation unit PG of the single cell 110A and the power generation unit PG of the single cell 110C are both rectangles of the same size with aligned outer edges when viewed in the vertical direction. . Therefore, according to the fuel cell stack 100 of the present embodiment, as described above, the thickest divided areas SAmax are evenly distributed in the circumferential direction of the first straight line L1, and the unit cells 110A in the vertical view , the shapes of the single cells 110B can be made to match each other.

Further, in the fuel cell stack 100 of the present embodiment, the plurality of unit cells 110 included in the plurality of power generation units 102 further divide any of the divided areas SA included in the third group G3 into the thickest divided area SAmax. and a single cell 110B which is a single cell 110 having a maximum thickness divided area SAmax which is one of the divided areas SA included in the fourth group G4. The third group G3 is a group composed of the divided area SA(1,1), the divided area SA(1,2), and the divided area SA(1,3). A fourth group G4 is a group composed of the divided area SA(3,1), the divided area SA(3,2), and the divided area SA(3,3). The third group G3 and the fourth group G4 are opposed to each other with the center point C of the virtual area VA interposed therebetween when viewed in the vertical direction, and the opposing direction is the same as that of the first group G1 and the second group G2. . . , 110D located at such locations are evenly dispersed in the circumferential direction of the first straight line L1. . In the fuel cell stack 100 of the present embodiment, the thickest divided regions SAmax of the single cells 110A, . The circumferential position of the first straight line L1 of the relatively thick portion of is also particularly evenly distributed. Therefore, according to the fuel cell stack 100 of the present embodiment, in the joint forming step S14, the single cell 110 caused by the concentration of the pressure force on a part of the composite 109 (the part located in the thickest divided area SAmax). cracking can be more effectively suppressed.

In addition, in the fuel cell stack 100 of the present embodiment, the single cell 110B is divided by the maximum thickness in the single cell 110A with the first straight line L1 (virtual straight line in the vertical direction passing through the center point C of the virtual area VA) as the axis of rotation. The divided area SA located at a position obtained by rotating the area SAmax by 90° is set as the thickest divided area SAmax. In the single cell 110D, the thickest divided area SAmax is the divided area SA located at a position where the thickest divided area SAmax in the single cell 110A is rotated by 270° about the first straight line L1 as the rotation axis. Therefore, the single cell 110C, the single cell 110B, and the single cell 110D are obtained by rotating the thickest divided area SAmax in the single cell 110A by 90°, 180°, and 270°, respectively, about the first straight line L1 as the rotation axis. is the thickest divided area SAmax, and in the single cell 110A, as described above, the thickest divided area SAmax in the single cell 110A is set to 0° ( Alternatively, the divided area SA located at a position rotated by 360° is set as the thickest divided area SAmax. In the fuel cell stack 100 of the present embodiment, the thickest divided regions SAmax of the single cells 110A, . The circumferential position of the first straight line L1 of the relatively thick portion of is also particularly evenly distributed. Therefore, according to the fuel cell stack 100 of the present embodiment, the pressure force is concentrated on a portion of the composite 109 (the portion located in the thickest divided region SAmax) in the joint forming step S14 during manufacturing. Cracking of the single cell 110 caused by this can be suppressed more effectively.

In the fuel cell stack 100 of the present embodiment, the single cell 110A, the single cell 110C, the single cell 110B, and the single cell 110D included in the plurality of single cells 110 included in the plurality of power generation units 102 are , the unit cells 110A, 110B, 110C, and 110D are arranged in this order in the vertical direction and are adjacent to each other. Therefore, according to the fuel cell stack 100 of the present embodiment, by arranging the plurality of single cells 110 while rotating them by 90°, the above-described “vertical direction of the single cell 110A (0°), single cell A configuration in which the cells 110B (90°), the single cells 110C (180°), and the single cells 110D (270°) are arranged in this order can be easily realized (manufactured).

In addition, in the fuel cell stack 100 of the present embodiment, when viewed in the vertical direction, the power generation unit PG of the single cell 110A, the power generation unit PG of the single cell 110B, the power generation unit PG of the single cell 110C, and the power generation unit PG of the single cell 110D The PGs are rectangles of the same size with aligned outer edges. According to the fuel cell stack 100 of the present embodiment, the thickest divided areas SAmax are evenly dispersed in the circumferential direction of the first straight line L1 as described above, and the single cells 110A, . . . , the shapes of the single cells 110D can be made to match each other.

In addition, in the fuel cell stack 100 of the present embodiment, the position of the thickest divided area SAmax in the specific single cell, which is at least one single cell 110, is the thinnest divided area SAmin in at least one single cell 110 other than the specific single cell. is the same as the position of The thinnest divided area SAmin is the average thickness in the vertical direction (Z-axis direction) of the portions located in each of the eight divided areas SA excluding the divided area SA(2,2) in each unit cell 110. It is the divided area SA that overlaps with the portion where at is the smallest. The position of the thickest divided area SAmax in the specific single cell is the same as the position of the thinnest divided area SAmin in at least one single cell 110 other than the specific single cell.

In a configuration (hereinafter referred to as “comparative configuration 2”) in which the positions of the thickest divided regions SAmax in all the single cells 110 included in the plurality of power generation units 102 are different from the positions of the thinnest divided regions SAmin, if In the joint forming step S14, the single cell 110 is particularly prone to cracking due to the concentration of pressure on the portion of the composite 109 located in the thickest divided area SAmax in the vertical direction.

In contrast, in the fuel cell stack 100 of the present embodiment, as described above, the position of the thickest divided area SAmax in at least one specific single cell 110 is located in at least one single cell other than the specific single cell. It is the same as the position of the thinnest divided area SAmin in 110 . Therefore, in the fuel cell stack 100 of the present embodiment, in the manufacturing process, in comparison with the above comparative configuration 2, in the composite 109 in the joint forming step S14, the thickest divided region SAmax in the vertical view Concentration of the applied pressure on the positioned portion is suppressed. Therefore, according to the fuel cell stack 100 of the present embodiment, in the joint forming step S14, the single cell 110 caused by the concentration of the pressure force on a part of the composite 109 (the part located in the thickest divided area SAmax). can be particularly effectively suppressed.

Further, the method for manufacturing the fuel cell stack 100 of the present embodiment includes an electrode forming step S12, a composite manufacturing step S13, and a junction forming step S14. The electrode forming step S12 is a step of forming a plurality of air electrodes 114 by wet-film-forming a material for the air electrodes 114 in a film-forming direction df perpendicular to the vertical direction. The composite preparation step S13 is a step of preparing the composite 109 . The composite 109 has a single cell 110 having an air electrode 114, a current collecting member 190 arranged on the opposite side of the air electrode 114 from the electrolyte layer 112 in the vertical direction, and a pre-bonding joint 139. It is a member provided with a plurality of pre-joining power generation units 107 . The pre-joining joint portion 139 is a member that becomes the joint portion 138 . The pre-bonding bonding portion 139 is positioned between the unit cell 110 and the current collecting member 190 in the vertical direction. The plurality of pre-joining power generation units 107 are arranged side by side in the vertical direction. The film formation direction df in the specific single cell, which is at least one single cell 110, is different from the film formation direction df in at least one single cell 110 other than the specific single cell. The joining portion forming step S13 is a step of forming the joining portion 138 by applying pressure to the composite 109 in the vertical direction. According to this manufacturing method, it is possible to suppress cracking of the single cell 110 due to concentration of pressure on a portion of the composite 109 (portion located in the thickest divided region SAmax) in the joint forming step S14. can.

In addition, in the present manufacturing method, in the composite manufacturing step S13, the plurality of single cells 110 included in the plurality of power generation units 102 are composites 109 each including a single cell 110A, a single cell 110C, a single cell 110B, and a single cell 110D. It is a process of making. In the single cell 110C, the film formation direction is the direction obtained by rotating the film formation direction df of the single cell 110A by 180° with the first straight line L1 (virtual straight line in the vertical direction passing through the center point C of the virtual area VA) as the rotation axis. df. In the single cell 110B, the film formation direction df is obtained by rotating the film formation direction df in the single cell 110A by 90° with the first straight line L1 as the rotation axis. In the unit cell 110D, the film formation direction df is obtained by rotating the film formation direction df in the unit cell 110A by 270° with the first straight line L1 as the rotation axis. According to this manufacturing method, the plurality of unit cells 110 are rotated by 90° and arranged, thereby achieving the above-described “vertical direction, unit cell 110A (0°), unit cell 110C (90°), A configuration in which the single cells 110B (180°) and the single cells 110D (270°) are arranged in this order can be easily realized (manufactured).

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.

The configuration of the fuel cell stack 100 and the configuration of each part that constitutes the fuel cell stack 100 in the above embodiment are merely examples, and various modifications are possible. For example, the materials forming each member in the above-described embodiments are merely examples, and each member may be formed of another material. Also, the number of power generation units 102 and the number of unit cells 110 are merely examples, and various modifications are possible.

In the above-described embodiment (or modified example, the same shall apply hereinafter), the air electrode 114 is formed by screen printing in the electrode forming step S12. ) may form the air electrode 114 (or the anode 116). Even when another method is used, the film forming direction df may be taken into account as in the above embodiment.

The configuration of each power generation unit 102 (particularly the single cell 110) is such that "the position of the thickest divided area SAmax in a specific single cell that is at least one single cell 110 is the thickest in at least one single cell 110 other than the specific single cell. It is not limited to the configuration in the above-described embodiment, and other configurations may be used as long as the condition "the position is different from the position of the thickness division region SAmax" is satisfied. For example, the distribution of the thickness (in particular, the average thickness at) of each unit cell 110 (for example, the position of the thickest divided area SAmax and the position of the thinnest divided area SAmin) differs from that of the above embodiment. good too. Moreover, the configuration may include only a portion of the plurality of power generation units 102 (or the plurality of unit cells 110 included in the plurality of power generation units 102). Of the single cells 110A, . good too. In addition, in the above-described embodiment (or modification), between the power generation units 102 (particularly the unit cells 110) may be further provided between other power generation units 102 (particularly the single cells 110). In such a configuration as well, "the position of the thickest divided region SAmax in the specific single cell that is at least one single cell 110 is different from the position of the thickest divided region SAmax in at least one single cell 110 other than the specific single cell." For the same reason as in the above embodiment, by satisfying the condition that the pressure is concentrated on a part of the composite 109 (the part located in the thickest divided area SAmax) in the joint part forming step S14. Cracking of the single cell 110 caused by this can be suppressed.

In addition, the configuration of each power generation unit 102 (especially the single cell 110) is such that "the plurality of single cells 110 included in the plurality of power generation units 102 maximizes any of the divided areas SA included in the first group G1. includes a single cell 110 having a thickness divided area SAmax and a single cell 110 having a maximum thickness divided area SAmax that is any of the divided areas SA included in the second group G2". The configuration is not limited to the configuration in the above embodiment, and other configurations may be employed. For example, the distribution of the thickness (in particular, the average thickness at) of each unit cell 110 (for example, the position of the thickest divided area SAmax and the position of the thinnest divided area SAmin) differs from that of the above embodiment. good too. Also in such a configuration, "the plurality of single cells 110 included in the plurality of power generation units 102 are the single cells 110 in which any of the divided areas SA included in the first group G1 is the thickest divided area SAmax. , and the single cell 110 having the thickest divided region SAmax in any one of the divided regions SA included in the second group G2. It is possible to more effectively suppress cracking of the single cell 110 due to concentration of pressure on a portion of the composite 109 (portion located in the thickest divided region SAmax) in the forming step S14.

In addition, the configuration of each power generation unit 102 (particularly, the single cell 110) is such that "the single cell 110 is a single cell with a first straight line L1 (virtual straight line in the vertical direction passing through the center point C of the virtual area VA) as a rotation axis. The thickest divided area SAmax is the divided area SA located at a position where the thickest divided area SAmax in 110 is rotated by 180°." may be configured. In such a configuration as well, the single cell 110 is configured such that the maximum thickness divided area SAmax in the single cell 110 is 180° with the first straight line L1 (virtual straight line in the vertical direction passing through the center point C of the virtual area VA) as the axis of rotation. By satisfying the condition that the divided area SA located at the rotated position is the thickest divided area SAmax, for the same reason as in the above embodiment, a part of the composite 109 is formed in the joint forming step S14. Cracking of the single cell 110 due to concentration of pressure on (the portion located in the thickest divided area SAmax) can be more effectively suppressed.

In addition, the configuration of each power generation unit 102 (particularly the single cell 110) is such that "the plurality of single cells 110 included in the plurality of power generation units 102 maximizes any of the divided areas SA included in the third group G3. A single cell 110D that is a single cell 110 having a thickness divided area SAmax, and a single cell 110B that is a single cell 110 having a thickest divided area SAmax that is any of the divided areas SA included in the fourth group G4. The configuration is not limited to the configuration in the above embodiment, and other configurations may be employed as long as the condition "there is a For example, the distribution of the thickness (in particular, the average thickness at) of each unit cell 110 (for example, the position of the thickest divided area SAmax and the position of the thinnest divided area SAmin) differs from that of the above embodiment. good too. In such a configuration as well, "the plurality of single cells 110 included in the plurality of power generation units 102 are unit cells 110 in which any of the divided areas SA included in the third group G3 is the thickest divided area SAmax. a certain unit cell 110D and a unit cell 110B which is a unit cell 110 having a maximum thickness divided area SAmax of any of the divided areas SA included in the fourth group G4" is satisfied. For the same reason as in the embodiment, cracking of the single cell 110 due to concentration of pressure on a portion of the composite 109 (portion located in the thickest divided region SAmax) in the joint forming step S14 is more effectively prevented. can be effectively suppressed.

The configuration of each power generation unit 102 (particularly the single cell 110) is such that "the position of the thickest divided area SAmax in a specific single cell that is at least one single cell 110 is the thickest in at least one single cell 110 other than the specific single cell. It is not limited to the configuration in the above-described embodiment, and other configurations may be used as long as the condition "the position is the same as that of the thinly divided area SAmin" is satisfied. For example, the distribution of the thickness (in particular, the average thickness at) of each unit cell 110 (for example, the position of the thickest divided area SAmax and the position of the thinnest divided area SAmin) differs from that of the above embodiment. good too. Also in such a configuration, "the position of the thickest divided region SAmax in the specific single cell that is at least one single cell 110 is the same as the position of the thinnest divided region SAmin in at least one single cell 110 other than the specific single cell. By satisfying the condition that the pressure is concentrated on a part of the composite 109 (the part located in the thickest divided area SAmax) in the joint part forming step S14 for the same reason as in the above embodiment. Cracking of the single cell 110 caused by this can be suppressed particularly effectively.

In the above-described embodiment, the power generation units 102 are all rectangular with the same dimensions when viewed in the vertical direction, but some or all of the power generation units 102 may be configured to have unequal dimensions or non-rectangular configurations.

In the above-described embodiment, the power generating units PG of the unit cells 110 are rectangular with the same size and the outer edges are aligned when viewed in the vertical direction. It may be a non-rectangular configuration, a non-equal size configuration, or a non-rectangular configuration.

In the above embodiment, each side of the rectangle indicating (the outline of) the virtual area VA is in contact with all the power generation units PG of the plurality of power generation units 102, but the virtual area VA (the outline of) the virtual area VA is Each side of the illustrated rectangle does not need to be in contact with all of the power generation units PG of the plurality of power generation units 102 as long as it is in contact with any one of the power generation units PG.

In the above embodiment, the air electrode 114 is formed by screen printing in the electrode forming step S12. Alternatively, the fuel electrode 116) may be formed. Even when using another method, the film forming direction df in the other method may be taken into consideration, as in the above embodiment.

In the above-described embodiment, the collector member 190 is arranged on the upper side of the air electrode 114 (the side opposite to the electrolyte layer 112 in the vertical direction) and is electrically connected to the air electrode 114, and the unit cells 110 in the vertical direction and a current collecting member 190 and a conductive joint 138 that joins the single cell 110 and the current collecting member 190 . In place of or in addition to the current collecting member 190 and the joint 138, the current collecting member 190 is arranged on the lower side of the fuel electrode 116 (the side opposite to the electrolyte layer 112 in the vertical direction), and is electrically connected to the fuel electrode 116. A current collecting member to be connected (hereinafter referred to as a "fuel electrode side current collecting member") is positioned between the single cell 110 and the fuel electrode side current collecting member in the vertical direction, and the single cell 110 and the fuel electrode side current collecting member are positioned. A conductive joint portion (hereinafter referred to as a “fuel electrode side joint portion”) that joins the electrical member may also be provided. In the configuration including the fuel electrode side current collecting member and the fuel electrode side joint portion, as in the configuration including the current collecting member 190 and the joint portion 138, cracking of the single cell 110 due to the variation in the thickness of the fuel electrode 116 occurs. Although it may be a problem, "the position of the thickest divided region SAmax in a specific single cell that is at least one single cell 110 is different from the position of the thickest divided region SAmax in at least one single cell 110 other than the specific single cell. By adopting the configuration, for the same reason as in the above embodiment, the pressure force is concentrated on a part of the composite 109 (the part located in the thickest divided area SAmax) in the joint forming step S14. Cracking of the single cell 110 can be suppressed.

Further, in the above-described embodiment, the target is the fuel cell stack 100 that generates power using the electrochemical reaction between hydrogen contained in the fuel gas and oxygen contained in the oxidant gas, but the present specification discloses The technology is equally applicable to electrolytic cell stacks comprising a plurality of electrolytic single cells, which are the building blocks of a solid oxide electrolytic cell (SOEC) that utilizes the electrolysis reaction of water to produce hydrogen.

Further, in the above embodiments, a solid oxide fuel cell (SOFC) was described as an example, but the technology disclosed in this specification can be applied to other types of fuel cells (such as a molten carbonate fuel cell (MCFC)). or electrolytic cell).

22 (22A, ..., 22E): bolt 24: nut 26: insulating sheet 27: gas passage member 28: body portion 29: branching portion 32, 34: hole 44: conductive portion 45: cover member facing portion 46: interconnector Opposing part 47: Connecting part 48: Connecting member 49: Elastic part 50: Cover member 58: Upper specific space 60: Separator for cover 61: Third separator through-hole 66: Inner part 67: Outer part 68: Connecting part 70: Upper terminal plate 71: hole 78: protrusion 80: lower terminal plate 88: protrusion 92: upper insulating sheet 94: hole 96: lower insulating sheet 100: fuel cell stack 102 (102A, ..., 102G): power generation unit 102X: Upper specific power generation unit 103: Power generation block 104: Upper end plate 106: Lower end plate 107: Power generation unit before bonding 108: Communication hole 109: Composite 110 (110A, ..., 110G): Single cell 112: Electrolyte layer 114: air electrode 116: fuel electrode 118: intermediate layer 120: single cell separator 121: first separator through-hole 122: first separator inner peripheral portion 124: joint portion 125: glass seal portion 126: inner portion 127: Outer portion 128: Connecting portion 130: Air electrode side frame 131: Hole 132: Oxidant gas supply communication hole 133: Oxidant gas discharge communication hole 134: Air electrode side current collector 138: Joint 139: Pre-joining joint 140 : fuel electrode side frame 141: hole 142: fuel gas supply passage 143: fuel gas discharge passage 144: conductive portion 145: electrode facing portion 146: interconnector facing portion 147: connecting portion 148: fuel electrode side current collecting member 149: Elastic portion 150: Flat plate portion 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 180: Separator for IC 180X: Maximum Upper IC separator 181: Second separator through-hole 181X: Second separator through-hole (of the uppermost IC separator) 182: Second separator inner peripheral portion 186: Inner portion 187: Outer portion 188: Connecting portion 190: Current collecting member 190X: Uppermost current collecting member 194: Coating layer 196: Conductive bonding material 270: Upper terminal unit FG: Fuel gas FOG: Fuel off-gas L1: First straight line OG: Oxidant gas OOG: Oxidant offgas PG: Power generation unit SA: Divided area SAmax: Thickest divided area SAmin: Thinnest divided area VA: Virtual area df: Film formation direction

Claims (7)

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, wherein the electrolyte layer, the air electrode and the fuel electrode are arranged in the first direction. A single cell having a power generation unit that overlaps with
a current collecting member disposed on a side opposite to the electrolyte layer in the first direction with respect to a specific electrode, which is one of the air electrode and the fuel electrode, and electrically connected to the specific electrode;
a conductive joint located between the single cell and the current collecting member in the first direction and joining the single cell and the current collecting member;
in an electrochemical reaction cell stack comprising a plurality of electrochemical reaction units arranged side by side in the first direction, each having
A rectangular imaginary area that includes all the power generation units included in the plurality of electrochemical reaction units when viewed from the first direction, wherein each side of the rectangle is one of the plurality of electrochemical reaction units Each region of 3 rows and 3 columns obtained by equally dividing each of the vertical and horizontal regions of the virtual region in contact with the power generation unit of is a divided region, and the divided region located in the i-th row and j-th column is a divided region (i, j) (i = 1, 2, 3, j = 1, 2, 3), and in each power generation unit, each part located in each of the eight divided regions excluding the divided region (2, 2) Among them, when the divided region overlapping with the portion having the largest average thickness in the first direction is defined as the thickest divided region,
the position of the thickest divided region in at least one specific single cell is different from the position of the thickest divided region in at least one of the single cells other than the specific single cell;
A group composed of the divided area (1,1), the divided area (2,1), and the divided area (3,1) is defined as the first group, and the divided area (1,3) and the divided area (2,3) ) and the divided region (3, 3) as the second group,
the plurality of single cells included in the plurality of electrochemical reaction units,
a first unit cell which is the unit cell having any one of the divided regions included in the first group as the thickest divided region;
a second single cell that is the single cell having any of the divided regions included in the second group as the thickest divided region;
A group composed of the divided area (1,1), the divided area (1,2), and the divided area (1,3) is defined as the third group, and the divided area (3,1) and the divided area (3,2) are defined as the third group. ) and the divided region (3, 3) as the fourth group,
The plurality of single cells included in the plurality of electrochemical reaction units further
a third single cell, which is the single cell having any one of the divided regions included in the third group as the thickest divided region;
a fourth unit cell which is the unit cell having any of the divided regions included in the fourth group as the thickest divided region;
An electrochemical reaction cell stack characterized by: The electrochemical reaction cell stack according to claim 1 ,
The second unit cell is located at a position obtained by rotating the thickest divided area of the first unit cell by 180° about a straight line in the first direction passing through the center point of the virtual area as a rotation axis. the single cell having the divided region as the thickest divided region;
The third unit cell is located at a position obtained by rotating the thickest divided area of the first unit cell by 90° with a straight line in the first direction passing through the center point of the virtual area as a rotation axis. the single cell having the divided region as the thickest divided region;
The fourth unit cell is located at a location obtained by rotating the thickest divided area in the first unit cell by 270° with a straight line in the first direction passing through the center point of the virtual area as a rotation axis. The single cell having the divided region as the thickest divided region,
An electrochemical reaction cell stack characterized by: The electrochemical reaction cell stack according to claim 1 or claim 2 ,
the first unit cell, the second unit cell, the third unit cell, and the fourth unit cell included in the plurality of unit cells included in the plurality of electrochemical reaction units; teeth,
The first unit cell, the third unit cell, the second unit cell, and the fourth unit cell are arranged in this order in the first direction and are adjacent to each other.
An electrochemical reaction cell stack characterized by: An electrochemical reaction cell stack according to any one of claims 1 to 3 ,
When viewed from the first direction, the power generation unit of the first unit cell, the power generation unit of the second unit cell, the power generation unit of the third unit cell, and the fourth unit cell The power generation unit of is a rectangle of the same size with the outer edges aligned,
An electrochemical reaction cell stack characterized by: An electrochemical reaction cell stack according to any one of claims 1 to 4 ,
In each of the single cells, among the portions located in each of the eight divided regions excluding the divided region (2, 2), the divided region overlapping the portion having the smallest average thickness in the first direction When the thinnest divided area is used,
The position of the thickest divided region in the specific single cell is the same as the position of the thinnest divided region in at least one of the single cells other than the specific single cell.
An electrochemical reaction cell stack characterized by: A method of manufacturing an electrochemical reaction cell stack according to claim 1, comprising:
a first step of forming a plurality of the specific electrodes by wet film-forming a material for the specific electrode in a film-forming direction orthogonal to the first direction;
The single cell having the specific electrode, the current collecting member disposed on the side opposite to the electrolyte layer in the first direction with respect to the specific electrode, and a pre-bonding member serving as the bonding portion a pre-bonding junction positioned between the single cell in the first direction and the current collecting member, the composite comprising a plurality of pre-bonding electrochemical reaction units, wherein a plurality of The pre-bonding electrochemical reaction units are arranged side by side in the first direction, and the film formation direction in at least one of the specific single cells is the same as that of at least one of the specific single cells other than the specific single cell. a second step of fabricating a composite that is different from the film formation direction in the single cell;
a third step of forming the joint by pressing the composite in the first direction;
with
The second step is
the plurality of single cells included in the plurality of electrochemical reaction units,
a first single cell;
A second single cell which is the single cell having a direction obtained by rotating the film formation direction of the first unit cell by 180° about the first straight line in the first direction as a rotation axis. and,
a third unit cell that is the unit cell whose film formation direction is a direction obtained by rotating the film formation direction of the first unit cell by 90° about the first straight line as a rotation axis;
a fourth unit cell that is the unit cell whose film formation direction is the direction obtained by rotating the film formation direction of the first unit cell by 270° about the first straight line as a rotation axis; A step of producing the composite,
A method for manufacturing an electrochemical reaction cell stack, characterized by: A method for manufacturing an electrochemical reaction cell stack according to claim 6,
The first single cell, the second single cell, the third single cell, and the fourth single cell are single cells manufactured under the same manufacturing conditions,
A method for manufacturing an electrochemical reaction cell stack, characterized by:

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