JP7232224B2 - Electrochemical reaction cell stack - Google Patents

Description

The technology disclosed by this specification relates to an electrochemical reaction cell stack.

A solid oxide fuel cell (hereinafter referred to as "SOFC") is known as one type of fuel cell that generates power using an electrochemical reaction between hydrogen and oxygen. A fuel cell power generation unit (hereinafter referred to as a "power generation unit"), which is a structural unit of an SOFC, includes a fuel cell single cell (hereinafter referred to as a "single cell"), an interconnector, and a single cell separator.

The single cell includes an electrolyte layer, an air electrode arranged on one side of the electrolyte layer in a predetermined direction (hereinafter referred to as "first direction"), and an air electrode arranged on the other side of the electrolyte layer in the first direction. and a fuel electrode. The interconnector is arranged on one side of the air electrode in the first direction and electrically connected to the air electrode. The single cell separator has a substantially plate shape. The single-cell separator is formed with a through-hole penetrating in the first direction (hereinafter referred to as "first separator through-hole"). A portion of the single-cell separator surrounding the first separator through-hole is located between the electrolyte layer and the interconnector.

JP 2020-9744 A

In conventional fuel cells, temperature changes during operation cause the unit cells and interconnectors to thermally expand or contract and warp, shortening the distance between the unit cells and interconnectors. Separators and interconnectors may come into contact with each other. This may cause a short circuit between the single cell separator and the interconnector.

Such problems are also common to electrolytic cell stacks, which are a form of solid oxide electrolysis 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) The electrochemical reaction cell stack disclosed in the present specification includes an electrolyte layer, an air electrode disposed on one side of the electrolyte layer in the first direction, and an air electrode disposed on one side of the electrolyte layer in the first direction. a fuel electrode arranged on the other side; an interconnector arranged on the one side of the air electrode, the interconnector being electrically connected to the air electrode; and having a first separator through-hole penetrating in the first direction, wherein the first separator inner circumference is a portion surrounding the first separator through-hole Each section includes a single cell separator positioned between the electrolyte layer and the interconnector plate section, and is composed of a plurality of electrochemical reaction units arranged side by side in the first direction. is located between the first separator inner peripheral portion and the interconnector, and is between the first separator inner peripheral portion and the interconnector when viewed in the first direction A plurality of insulating portions having overlapping portions are arranged along the circumferential direction of the inner peripheral portion of the first separator while being spaced apart from each other.

According to this electrochemical reaction cell stack, when the unit cells and interconnectors are warped due to thermal expansion or thermal contraction due to temperature changes during operation, the existence of the plurality of insulating portions described above prevents the single cell separator from Short-circuiting with the interconnector can be suppressed.

Since the insulating part faces the air chamber through which the oxidant gas passes (strictly speaking, it is the space between the single cell and the interconnector, and is part of the air chamber), it is necessary to avoid the oxidant gas as much as possible. It is preferable to have a configuration that does not impede the flow (and thus the diffusibility). If, in place of the plurality of insulating portions described above, an insulating portion formed along the entire circumference of the inner peripheral portion of the first separator is provided, the flow of the oxidant gas is hindered, and oxidation is prevented. Diffusivity of agent gas is remarkably reduced. On the other hand, in the electrochemical reaction cell stack of the present invention, a plurality of insulating portions are arranged along the circumferential direction of the inner peripheral portion of the first separator while being separated from each other. Since there is a space for the oxidizing gas to flow between the oxidizing portion and the oxidizing portion, obstruction of the flow of the oxidizing gas is reduced. Therefore, according to the present electrochemical reaction cell stack, compared with the configuration including the insulating portion formed along the entire circumferential direction of the inner peripheral portion of the first separator, the decrease in diffusibility of the oxidant gas is suppressed. can do.

(2) In the above electrochemical reaction cell stack, the at least one insulating portion may entirely overlap the single cell when viewed in the first direction.

In a configuration in which only a portion of a certain insulating portion (hereinafter referred to as a “specific insulating portion”) overlaps a single cell, each member (especially a single The cell separator) is particularly prone to thermal expansion or thermal contraction in the vicinity of the boundary between the portion overlapping the single cell and the portion not overlapping the single cell among the specific insulating portions when viewed from the first direction. Therefore, cracks may occur near the boundary between a portion of the specific insulating portion that overlaps the unit cell and a portion that does not overlap the unit cell when viewed in the first direction.

On the other hand, in the present electrochemical reaction cell stack, since the entire at least one insulating portion overlaps the single cell when viewed in the first direction, during operation of the electrochemical reaction cell stack, Even when each member (particularly, the single cell separator) thermally expands or contracts, cracking of the at least one insulating portion can be suppressed.

(3) In the above electrochemical reaction cell stack, when viewed in the first direction, the plurality of insulating portions are arranged along a second direction crossing the direction of gas flow in the air chamber facing the air electrode. composed of an upstream insulating portion located upstream of the air electrode in the gas flow direction, and a plurality of the insulating portions arranged along the second direction, wherein the gas At least one of a downstream side insulating portion group located downstream of the air electrode in the flow direction may be provided. According to the present electrochemical reaction cell stack, by including at least one of the above-described upstream insulating subgroup and downstream insulating subgroup, the decrease in the diffusibility of the oxidant gas is more effectively suppressed. be able to.

(4) In the above electrochemical reaction cell stack, assuming that an imaginary straight line passing through the center of the air electrode and along the flow direction of the gas is defined as a first straight line when viewed in the first direction, the upstream side Between adjacent insulating portions in a central side group composed of any of the plurality of insulating portions included in a specific insulating portion group that is at least one of the insulating portion group and the downstream side insulating portion group The interval is composed of a plurality of the insulating portions included in the specific insulating portion group, the insulating portions being further from the first straight line than the central side group. It may be configured to be larger than the spacing between adjacent insulating portions in the end groups.

During operation of the electrochemical reaction cell stack, the temperature on the center side of the air electrode in the air chamber as viewed in the first direction tends to be higher than the temperature on the end side. Due to the occurrence of such a temperature gradient, the oxidant gas is less likely to flow toward the center of the air electrode in the air chamber viewed from the first direction, and more likely to flow toward the ends. Therefore, in a configuration in which the distance between adjacent insulating portions in the upstream side insulating portion group is uniform, the gas flow in the air chamber on the center side of the air electrode and the gas flow on the end side will be uneven. , which degrades the electrical performance of the electrochemical reaction cell stack.

On the other hand, in the present electrochemical reaction cell stack including the upstream side insulating portion group, as described above, when viewed from the first direction, the adjacent insulating portions in the central side group of the upstream side insulating portion group The spacing is greater than the spacing between adjacent insulating portions in the end groups. With such a configuration, compared to a configuration in which the intervals between adjacent insulating portions in the upstream side insulating portion group are uniform, the gas flow in the air chamber on the center side of the air electrode and the end side becomes uniform with the gas flow in Similarly, in the present electrochemical reaction cell stack including the downstream side insulating portion group, for the same reason as the above-described upstream side insulating portion group, the distance between adjacent insulating portions in the downstream side insulating portion group is The gas flow is uniform at the center side of the air electrode in the air chamber and at the end sides, compared to a configuration in which the is uniform. Therefore, according to the present electrochemical reaction cell stack including the specific insulating portion group (at least one of the upstream insulating portion group and the downstream insulating portion group), the electrical performance of the electrochemical reaction cell stack is degraded. can be suppressed more effectively.

(5) In the above electrochemical reaction cell stack, in at least one specific cross section along the first direction, the cell separator includes an inner portion including the first separator inner peripheral portion, and the and an outer portion located on the outer peripheral side of the inner portion, and a connecting portion connecting the inner portion and the outer portion and protruding in the first direction with respect to both the inner portion and the outer portion. and may be provided.

In the present electrochemical reaction cell stack, since the single cell separator has the above-described inner portion, outer portion, and connecting portion, the distance between the single cell and the interconnector is likely to be shortened. Therefore, the present invention having a plurality of insulating portions as described above is particularly suitable for the present electrochemical reaction cell stack having such a configuration.

(6) In the above electrochemical reaction cell stack, an interconnector separator having a substantially plate shape and having a second separator through-hole penetrating in the first direction, the second separator an interconnector separator having a second separator inner peripheral portion surrounding a through-hole connected to the outer peripheral portion of the interconnector; and a pair of end members respectively positioned on both sides of the electrochemical reaction block in the first direction. and a fastening member that is inserted into a through-hole that penetrates the single cell separator, the interconnector separator, and the pair of end members in the first direction and fastens the electrochemical reaction block. may be

Since the present electrochemical reaction cell stack is configured to include the above-described interconnector separator, a pair of end members, and a fastening member, deformation in which the distance between the single cell and the interconnector is shortened easily occurs. Therefore, the present invention having a plurality of insulating portions as described above is particularly suitable for the present electrochemical reaction cell stack having such a configuration.

(7) In the above electrochemical reaction cell stack, the insulating portion may be made of glass or ceramic. According to this electrochemical reaction cell stack, it is possible to stably ensure good insulation of the insulating portion even when used in a high-temperature environment.

1 is a perspective view showing the external configuration of a fuel cell stack 100 according to this embodiment; FIG. Explanatory drawing 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. Explanatory diagram showing the XY cross-sectional configuration of the fuel cell stack 100 at the position VI-VI in FIG.

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 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, and the Y-axis direction corresponds to the second 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 generating 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 communication hole 108 corresponds to a through hole into which a fastening member is inserted, and the bolt 22 and the nut 24 correspond to fastening members in the claims.

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 . A hole in the branch portion 29 communicates with a hole in the main body portion 28 . A gas pipe (not shown) is connected to the branch portion 29 of each gas passage member 27 . Further, as shown in FIG. 2, the hole of the body portion 28 of the gas passage member 27 arranged at the position of the bolt 22A forming the 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 in the Z-axis direction, and are made of a conductive material such as stainless steel. Holes 32 and 34 penetrating in the Z-axis direction are formed near the center of the pair of end plates 104 and 106, respectively. As viewed in the Z-axis direction, 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 compressive force in the Z-axis direction by 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 single cell 110 described later). The upper end plate 104 and the lower end plate 106 correspond to a pair of end members in the claims.

(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 Z-axis 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. Constructed of an insulating material. A hole 94 communicating with the hole 32 of the upper end plate 104 and penetrating in the Z-axis direction is formed near the center of the upper insulating sheet 92 . As viewed in the Z-axis direction, the inner peripheral line of the hole 94 formed in the upper insulating sheet 92 includes each unit cell 110 described later. In this embodiment, the inner circumference of the hole 94 formed in the upper insulating sheet 92 substantially matches the inner circumference of the hole 32 formed in the upper end plate 104 as viewed in the Z-axis direction.

(Configuration of Terminal Plates 70, 80)
The pair of terminal plates 70 and 80 is a plate-like member having a substantially rectangular outer shape when viewed in the Z-axis direction, and is made of a conductive material such as stainless steel. A hole 71 penetrating in the Z-axis direction is formed near the center of the upper terminal plate 70 . As viewed in the Z-axis direction, 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 matches the inner circumference of the hole 32 formed in the upper end plate 104 as viewed in the Z-axis direction. The upper terminal plate 70 has a projecting portion 78 projecting outward from the outer circumference of the upper end plate 104 as viewed in the Z-axis direction, and the projecting portion 78 functions as a plus side output terminal of the fuel cell stack 100. do. In addition, the lower terminal plate 80 includes a projecting portion 88 projecting outward from the outer peripheral line of the lower end plate 106 as viewed in the Z-axis direction. Functions as an output pin.

(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, ten insulating portions 129 (129a, . . . , 129j), a pair of interconnectors 190 and a pair of and an IC separator 180 . 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 cross section of the fuel cell stack 100 shown in FIGS. 4 and 5 corresponds to the specific cross section in the claims.

The single cell 110 includes an electrolyte layer 112, an air electrode 114 arranged on one side (upper side) of the electrolyte layer 112 in the Z-axis direction, and an air electrode 114 arranged on the other side (lower side) of the electrolyte layer 112 in the Z-axis direction. It comprises an anode 116 and an intermediate layer 118 positioned between the electrolyte layer 112 and the cathode 114 . 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 electrolyte layer 112 is a substantially rectangular plate-shaped member when viewed in the Z-axis direction, 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 in the Z-axis direction, 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 in the Z-axis direction, and is formed of, for example, Ni (nickel), a cermet made of Ni and ceramic particles, a Ni-based alloy, or the like. ing. The intermediate layer 118 is a substantially rectangular plate-shaped member having substantially the same size as the air electrode 114 when viewed in the Z-axis direction, 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.

The single-cell separator 120 is a frame-like member having a substantially rectangular hole 121 (hereinafter referred to as “first separator through-hole 121”) extending in the Z-axis direction near the center. It is made of a conductive material such as. The single cell separator 120 has a substantially plate shape. The vertical thickness of the single cell separator 120 is, for example, about 0.05 mm or more and 0.2 mm or less, and is thinner than the vertical thickness (eg, 1 mm) of each of the frames 130 and 140 . 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 interconnector 190 (in the upper specific power generation unit 102X described later, the top interconnector 190X ) is located between Further, 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. In other words, the welded portion 241 that joins the single cell separator 120 and the fuel electrode frame 140 is formed at the position where the single cell separator 120 and the fuel electrode frame 140 are in contact with each other.

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 substantially flat plates extending in a direction substantially orthogonal to the Z-axis direction. Moreover, the connecting portion 128 has a curved shape that protrudes downward (in the Z-axis direction) with respect to both the inner portion 126 and the outer portion 127 . The lower side (fuel chamber 176 side) of connecting portion 128 is a convex portion, and the upper side (air chamber 166 side) portion of connecting portion 128 is a concave portion. Therefore, the connecting portion 128 includes portions whose positions in the Z-axis direction are different from those of the inner portion 126 and the outer portion 127 .

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 (the electrolyte layer in this embodiment) 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 interconnector 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 collectors 134 projecting from the flat plate portion 150 toward the air electrode 114 side. (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 Z-axis direction. In this embodiment, the surface of the interconnector 190 (the surface facing the air chamber 166) is formed with a conductive coating layer 194 made of, for example, spinel oxide. Below, the interconnector 190 covered with the covering layer 194 is simply referred to as the interconnector 190 . The interconnector 190 (more specifically, each air electrode-side current collector 134 of the interconnector 190) is connected to the air electrode 114 of the unit cell 110 via a conductive bonding material 196 made of, for example, spinel oxide. are spliced. Further, the surface of the interconnector 190 (the surface facing the fuel chamber 176 or the upper specific space 58 described below) is coated with a , a specific treatment (eg, annealing treatment) may be performed. The interconnectors 190 (except for the topmost interconnector 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 addition, in this embodiment, when two power generation units 102 are arranged adjacently, one interconnector 190 is shared by the two adjacent power generation units 102 . That is, the upper interconnector 190 in one power generation unit 102 is the same member as the lower interconnector 190 in another power generation unit 102 adjacent to the upper side of the power generation unit 102 . In addition, the lower interconnector 190 of the power generation unit 102 located on the lowest side in the fuel cell stack 100 is electrically connected to the lower terminal plate 80 via a conductive joint material 196 . In addition, the upper interconnector 190 (hereinafter also referred to as the "top interconnector 190X") of the power generation unit 102 located at the uppermost position in the fuel cell stack 100 (hereinafter also referred to as the "upper specific power generation unit 102X") is , IC separator 180 (hereinafter also referred to as “uppermost IC separator 180X”) and/or other members (connecting member 48, cover member 50, cover separator 60) to be described later to the upper terminal plate 70. electrically connected. That is, the upper terminal plate 70 is electrically connected to the power generation block 103 . The uppermost interconnector 190X is arranged below the upper terminal plate 70 in the Z-axis direction.

The IC separator 180 is a frame-shaped member having a substantially rectangular second separator through-hole 181 penetrating in the Z-axis direction near the center, and is made of a conductive material such as metal. The IC separator 180 has a substantially plate shape. In the present embodiment, a portion 182 (hereinafter referred to as “(hereinafter referred to as “second separator through-hole 182”)”) of the IC separator 180 surrounding the second separator through-hole 181 is the interconnector 190 ( It is joined to the upper surface of the outer peripheral portion of the flat plate portion 150) by laser welding. In other words, the welded portion 232 that joins the IC separator 180 and the interconnector 190 is formed at the position where the IC separator 180 and the interconnector 190 are in contact with each other. A portion of the welded portion 232 is exposed on the upper surface of the welded member (IC separator 180), and a portion of the welded portion 232 extends into the member to be welded (interconnector 190). Therefore, the IC separator 180 separates the air chamber 166 facing the air electrode 114 in one power generation unit 102 and the fuel chamber 176 facing the fuel electrode 116 in the other power generation unit 102 adjacent to that power generation unit 102. It is partitioned, and gas leak (cross leak) from one electrode side to the other electrode side in the outer peripheral portion of the interconnector 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 laser welding. In other words, the welded portion 231 that joins the IC separator 180 and the fuel electrode frame 140 is formed at the position where the IC separator 180 and the fuel electrode frame 140 are in contact with each other. 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 . The IC separator 180 corresponds to the interconnector separator in the claims.

Similar to 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 Z-axis direction near the center. It is made of metal. Further, in the present embodiment, the peripheral portion of the through hole in the uppermost IC separator 180X is joined to the upper surface of the outer peripheral portion of the uppermost interconnector 190X by laser welding. In other words, the welded portion 212 that joins the uppermost IC separator 180X and the uppermost interconnector 190X is formed at the position where the uppermost IC separator 180X and the uppermost interconnector 190X contact each other. 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. In other words, the welded portion 211 that joins the uppermost IC separator 180X and the upper terminal plate 70 is formed at the position where the uppermost IC separator 180X and the upper terminal plate 70 are in contact with each other.

The IC separator 180 has an inner portion 186 including a second separator through-hole (portion surrounding the second separator through-hole 181) 182 of the IC separator 180, and an outer portion 187 located outside 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 substantially flat plates extending in a direction substantially orthogonal to the Z-axis direction. Moreover, the connecting portion 188 has a curved shape that protrudes downward (in the Z-axis direction) with respect to both the inner portion 186 and the outer portion 187 .

The cathode-side frame 130 is a frame-shaped member having a substantially rectangular hole 131 penetrating in the Z-axis direction near the center, 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 consists of the outer peripheral portion of the surface of the single-cell separator 120 opposite to the side facing the electrolyte layer 112 (upper side) and the side facing the air chamber 166 of the upper IC separator 180 (lower side). 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 interconnectors 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 penetrating in the Z-axis direction near the center, and is made of metal, for example. A hole 141 in the anode-side frame 140 constitutes a fuel chamber 176 facing the anode 116 . The fuel electrode-side frame 140 is 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 interconnector 190, and is made of, for example, nickel, 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 interconnector 190 , an electrode facing portion 145 and an interconnector facing portion 146 . It has a connecting portion 147 that connects the . 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 disposed between the interconnector 190 and the elastic portion 149 in the Z-axis direction, and the electrode-facing portion 145 of the conductive portion 144 is disposed in the Z-axis direction. It is arranged between the pole 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 interconnector 190 are electrically connected via the fuel electrode side current collecting member 148. is well maintained. The configuration of the insulating portion 129 will be described later.

(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 in the Z-axis direction, and is made of a conductive material (for example, metal). Further, the surface of the cover member 50 (the surface facing the upper specific space 58 described later) is subjected to a specific treatment 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 adjacent to and separated from the upper interconnector 190 (top interconnector 190X) included in the upper specific power generation unit 102X in the Z-axis direction. 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 interconnector 190X. there is The upper specific space 58 is located 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 61 extending in the Z-axis direction near the center thereof, and is made of a conductive material such as metal. In the present embodiment, the portion of the cover separator 60 surrounding the hole 61 (hereinafter referred to as the “through hole surrounding portion”) is joined to the upper surface of the outer peripheral portion of the cover member 50 by laser welding. In other words, the welded portion 222 that joins the cover separator 60 and the cover member 50 is formed at the position where the cover separator 60 and the cover member 50 are in contact with each other. 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. In other words, the welded portion 221 that joins the cover separator 60 and the upper terminal plate 70 is formed at the position where the cover separator 60 and the upper terminal plate 70 are in contact with each other. The upper specific space 58 is defined by the cover separator 60 (and the uppermost IC separator 180X joined to the uppermost interconnector 190X).

The cover separator 60 includes an inner portion 66 including the through-hole peripheral portion (portion surrounding the hole 61) of the cover separator 60, an outer portion 67 located outside the inner portion 66, and the inner portion 66 and the outer portion 67. and a connection portion 68 that connects the In this embodiment, the inner portion 66 and the outer portion 67 are substantially flat plates extending in a direction substantially orthogonal to the Z-axis direction. Further, the connecting portion 68 has a curved shape that protrudes downward from both the inner portion 66 and the outer portion 67 .

Further, as shown in FIGS. 4 and 5, the fuel cell stack 100 of this embodiment further includes a connecting member 48 arranged in the upper specific space 58. As shown in FIG. 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 interconnector 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 interconnector 190X, and an interface with the cover member facing portion 45. It has a connecting portion 47 that connects with the connector facing portion 46 . The elastic portion 49 is a portion for ensuring the elasticity of the connecting member 48, and is made of mica or the like, for example. The interconnector facing portion 46 of the conductive portion 44 is arranged between the uppermost interconnector 190X and the elastic portion 49 in the Z-axis direction, and the cover member facing portion 45 of the conductive portion 44 is disposed in the Z-axis direction. It is arranged between the cover member 50 and the elastic portion 49 in the direction.

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 on one side (upper side) of the power generation block 103 in the Z-axis direction, and includes the upper terminal plate 70, the uppermost interconnector 190X, the cover member 50, and the connection member 48. , a top IC separator 180X, and a cover separator 60. As shown in FIG. 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 interconnector 190 via the conductive bonding material 196, and the fuel electrode 116 is connected to the interconnector 190 via the fuel electrode side collector member 148. electrically connected. That is, the plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. In the fuel cell stack 100, the upper interconnector 190 (top interconnector 190X) of the uppermost power generation unit 102 (upper specific power generation unit 102X) is electrically connected to the upper terminal plate 70, The lower interconnector 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 offgas 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 Further, as shown in FIGS. 3 and 5, the fuel offgas 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. 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. Configuration of insulating portion 129:
FIG. 6 is an explanatory diagram showing the XY cross-sectional configuration of the fuel cell stack 100 at the position VI-VI in FIG. The configuration of the insulating portion 129 will be described below with reference to FIGS. 4 and 6. FIG.

As described above, the fuel cell stack 100 of this embodiment includes ten insulating portions 129 (129a, . . . , 129j). Each insulating portion 129 is made of glass. Each insulating portion 129 has a substantially chevron shape when viewed in the Y-axis direction as shown in FIG. 4, and a substantially circular shape when viewed in the Z-axis direction as shown in FIG.

As shown in FIG. 4, each insulating portion 129 is arranged on the upper surface of the first separator inner circumferential portion 122 (the portion surrounding the first separator through-hole 121 in the single-cell separator 120).

Each insulating portion 129 is located between the first separator inner periphery 122 and the interconnector 190 . In the present embodiment, each insulating portion 129 is positioned outside the glass seal portion 125 and separated from the glass seal portion 125 when viewed in the Z-axis direction.

Each insulating portion 129 overlaps the first separator inner peripheral portion 122 and the interconnector 190 when viewed in the Z-axis direction. Therefore, it can be said that each insulating portion 129 has a portion that overlaps the first separator inner peripheral portion 122 and the interconnector 190 when viewed in the Z-axis direction.

In this embodiment, each insulating portion 129 (each of ten insulating portions 129 in this embodiment) as a whole overlaps the single cell 110 when viewed in the Z-axis direction.

As shown in FIG. 6, the ten insulating portions 129 (129a, . I'm in.

Five insulating portions 129 (129a, . . . , 129e) out of ten insulating portions 129 (129a, . , and are arranged along the Y-axis direction (the direction intersecting with the flow direction FD of the oxidant gas OG in the air chamber 166). The five insulating portions 129 (129a, . . . , 129e) are arranged in the negative Y-axis direction in the order 129a, 129b, 129c, 129d, 129e. Hereinafter, the group G1 composed of the five insulating portions 129 (129a, . . . , 129e) will be referred to as "upstream side insulating portion group G1".

A straight line L1 shown in FIG. 6 (hereinafter referred to as “first straight line L1”) is an imaginary straight line passing through the center C of the air electrode 114 and along the flow direction FD of the oxidizing gas OG when viewed in the Z-axis direction. is. Note that the center C of the air electrode 114 may be interpreted as the center of gravity of the air electrode 114 . Hereinafter, among the five insulating portions 129 (129a, . Then, the group G11 composed of the three insulating portions 129b, 129c, 129d) is referred to as a "central side group G11", and a plurality of insulating portions separated from the first straight line L1 as compared with the central side group G11. A group G12 composed of the insulating portions 129 (in this embodiment, four insulating portions 129a, 129b, 129d, and 129e) is called an "end side group G12." Note that the “group B composed of a plurality of insulating portions 129 farther from the first straight line L1 than in the group A” here means “at least one insulating portion included in the group B. 129 is a group that satisfies the condition that "it is farther from the first straight line L1 than any of the insulating portions 129 included in group A".

When viewed in the Z-axis direction, the distance between the adjacent insulating portions 129 in the center side group G11 (the distance I12 between the insulating portions 129b and 129c, and the distance I13 between the insulating portions 129c and 129d) is , the distance between adjacent insulating portions in the end group G12 (the distance I11 between the insulating portions 129a and 129b and the distance I14 between the insulating portions 129d and 129e). In this embodiment, the interval I12 between the insulating portions 129b and 129c and the interval I13 between the insulating portions 129c and 129d are the same. Also, the interval I11 between the insulating portions 129a and 129b and the interval I14 between the insulating portions 129d and 129e are the same.

Like the five insulating portions 129 (129a, . The five insulating portions 129 (129f, . . . , 129j) of are located downstream of the air electrode 114 in the X-axis direction and are arranged along the Y-axis direction. The five insulating portions 129 (129f, . . . , 129j) are arranged in the negative Y-axis direction in the order 129f, 129g, 129h, 129i, 129j. Hereinafter, the group G2 composed of the five insulating portions 129 (129f, . . . , 129j) will be referred to as "downstream insulating portion group G2". In addition, among the five insulating portions 129 (129f, . Then, the group G21 composed of the three insulating portions 129g, 129h, 129i) is referred to as a "central side group G21", and a plurality of insulating portions separated from the first straight line L1 as compared with the central side group G21. A group G22 composed of the insulating portions 129 (in this embodiment, four insulating portions 129f, 129g, 129i and 129j) is called an "end side group G22".

When viewed in the Z-axis direction, the distance between the adjacent insulating portions 129 in the center side group G21 (the distance I22 between the insulating portions 129g and 129h and the distance I23 between the insulating portions 129h and 129i) is , the distance between adjacent insulating portions in the end group G22 (the distance I21 between the insulating portions 129f and 129g and the distance I24 between the insulating portions 129i and 129j). In this embodiment, the interval I22 between the insulating portion 129g and the insulating portion 129h and the interval I23 between the insulating portion 129h and the insulating portion 129i are the same. Also, the interval I21 between the insulating portion 129f and the insulating portion 129g and the interval I24 between the insulating portion 129i and the insulating portion 129j are the same.

Moreover, the power generation unit 102 of this embodiment further includes a felt member 41 . As shown in FIG. 6, in the air chamber 166, the felt members 41 are positioned at both ends (in the Z-axis direction) of the direction (Y-axis direction) perpendicular to the main flow direction (X-axis direction) of the oxidant gas OG (single cell position). 110 at a position not overlapping with the air electrode 114). Although not shown, the felt members 41 are positioned at both ends (in the Z-axis direction) of the fuel chamber 176 in the direction (X-axis direction) orthogonal to the main flow direction (Y-axis direction) of the fuel gas FG. A position not overlapping the air electrode 114 of the unit cell 110) is also filled. Due to the presence of the felt member 41, the oxidizing gas OG supplied to the air chamber 166 or the fuel gas FG supplied to the fuel chamber 176 passes through the region that does not contribute much to power generation and is discharged from the air chamber 166 or the fuel chamber 176. can be suppressed, and the power generation efficiency can be improved.

A-4. Effect of this embodiment:
As described above, the fuel cell stack 100 of this embodiment includes the power generation block 103 composed of a plurality of (seven in this embodiment) power generation units 102 arranged side by side in the Z-axis direction (vertical direction). . The power generation unit 102 includes a single cell 110 , an interconnector 190 and a single cell separator 120 . The single cell 110 includes an electrolyte layer 112, an air electrode 114 arranged on one side (upper side) of the electrolyte layer 112 in the Z-axis direction, and an air electrode 114 arranged on the other side (lower side) of the electrolyte layer 112 in the Z-axis direction. and a fuel electrode 116 . The interconnector 190 is arranged on one side (upper side) of the air electrode 114 in the Z-axis direction, and is electrically connected to the air electrode 114 . The single cell separator 120 is a member having a substantially plate shape and having a first separator through-hole 121 penetrating in the Z-axis direction. First separator inner peripheral portion 122 (the portion of first separator inner peripheral portion 122 surrounding first separator through-hole 121 ) is located between electrolyte layer 112 and interconnector 190 . The fuel cell stack 100 is located between the first separator inner peripheral portion 122 and the interconnector 190 and has a portion overlapping the first separator inner peripheral portion 122 and the interconnector 190 as viewed in the Z-axis direction. A plurality (10 in this embodiment) of insulating portions 129 (129a, . . . , 129j) are provided. A plurality of insulating parts 129 (129a, .

According to the fuel cell stack 100 of this embodiment, when the unit cells 110 and the interconnectors 190 are warped due to thermal expansion or thermal contraction due to temperature changes during operation, the plurality of insulating portions 129 (129a, . . . , 129j), short-circuiting between the single cell separator 120 and the interconnector 190 can be suppressed.

Since the insulating portion 129 faces an air chamber 166 (strictly speaking, a space between the single cell 110 and the interconnector 190 and a part of the air chamber 166) through which the oxidant gas OG passes, It is preferable to have a configuration that does not impede the flow (and thus diffusion) of the oxidant gas OG as much as possible. If, instead of the plurality of insulating portions 129 described above, an insulating portion formed over the entire circumferential direction of the first separator inner peripheral portion 122 is provided, the flow of the oxidant gas OG is obstructed. , and the diffusibility of the oxidant gas OG is remarkably lowered. In contrast, in the fuel cell stack 100 of the present embodiment, a plurality of insulating portions 129 are arranged along the circumferential direction of the first separator inner peripheral portion 122 while being spaced apart from each other. Since there is a space between the insulating portion 129 and the insulating portion 129 through which the oxidant gas OG flows, the obstruction to the flow of the oxidant gas OG is reduced. Therefore, according to the fuel cell stack 100 of the present embodiment, diffusion of the oxidant gas OG is greater than that of the configuration including the insulating portion 129 formed over the entire circumference of the first separator inner peripheral portion 122 in the circumferential direction. It is possible to suppress the decrease in sexuality.

From the viewpoint of suppressing the short circuit between the single cell separator 120 and the interconnector 190 as described above, the width of the insulating portion 129 in the Z-axis direction is set to be equal to that of the first separator inner peripheral portion 122 and the interconnector 190. (In this embodiment, the flat plate portion 150) is preferably 20% or more of the width (width in the Z-axis direction) of the space, and more preferably 30% or more. In addition, from the viewpoint of suppressing the short circuit between the single cell separator 120 and the interconnector 190 as described above and suppressing the decrease in the diffusibility of the oxidant gas OG, the Y-axis direction ( The distance between the adjacent insulating portions 129 in the direction in which the plurality of insulating portions 129 are arranged) is 100% or more and 500% or less of the width of the adjacent insulating portions 129 (the width in the Y-axis direction). is particularly preferable, and it is more preferably 200% or more and 400% or less.

In addition, in the fuel cell stack 100 of this embodiment, the entire insulating portion 129 (each of the ten insulating portions 129 in this embodiment) overlaps the single cell 110 as viewed in the Z-axis direction.

In a configuration in which only a portion of a certain insulating portion 129 (hereinafter referred to as a “specific insulating portion”) overlaps with the unit cell 110, each member (especially the unit The cell separator 120) tends to thermally expand or contract in the vicinity of the boundary between the portion overlapping the unit cell 110 and the portion not overlapping the unit cell 110 among the specific insulating portions when viewed in the Z-axis direction. Therefore, cracks may occur near the boundary between a portion of the specific insulating portion that overlaps the unit cell 110 and a portion that does not overlap the unit cell 110 as viewed in the Z-axis direction.

In contrast, in the fuel cell stack 100 of the present embodiment, the insulating portions 129 (ten insulating portions 129 in the present embodiment) as a whole overlap the unit cells 110 as viewed in the Z-axis direction. Thus, cracking of the insulating portion 129 can be suppressed even when each member (in particular, the single cell separator 120) thermally expands or contracts during operation of the fuel cell stack 100. FIG.

Further, the fuel cell stack 100 of this embodiment includes an upstream insulating subgroup G1. The upstream side insulating portion group G1 includes a plurality of insulating portions 129 (in this embodiment) arranged along the Y-axis direction (the direction intersecting the flow direction FD of the oxidant gas OG in the air chamber 166) when viewed in the Z-axis direction. In form, it is a group composed of five insulating portions (129a, . . . , 129e). The upstream side insulating partial group G1 is located upstream of the air electrode 114 in the X-axis direction (the flow direction FD of the oxidant gas OG). According to the fuel cell stack 100 of the present embodiment, by including the above-described upstream insulating subgroup G1, it is possible to more effectively suppress the deterioration of the diffusibility of the oxidant gas OG.

Further, the fuel cell stack 100 of this embodiment includes a downstream insulating subgroup G2. The downstream side insulating subgroup G2 extends along the Y-axis direction (the direction intersecting the flow direction (X-axis direction) FD of the oxidant gas OG in the air chamber 166 facing the air electrode 114) when viewed in the Z-axis direction. 129 (in this embodiment, five insulating portions (129f, . . . , 129j)) arranged in a row. The downstream side insulating subgroup G2 is located downstream of the air electrode 114 in the X-axis direction (the flow direction FD of the oxidant gas OG). According to the fuel cell stack 100 of the present embodiment, by including the downstream insulating subgroup G2 described above, it is possible to more effectively suppress a decrease in the diffusibility of the oxidant gas OG.

Further, in the fuel cell stack 100 of the present embodiment, when viewed in the Z-axis direction, the distance (I12, I13) between the adjacent insulating portions 129 in the center side group G11 of the upstream side insulating portion group G1 is It is larger than the spacing (I11, I14) between adjacent insulating portions 129 in G12. It is a group composed of a plurality of insulating portions 129 (three insulating portions 129b, 129c, 129d in this embodiment) included in the center side group G11. The end side group G12 is a plurality of insulating portions 129 included in the upstream side insulating portion group G1 (129a, . It is a group composed of a plurality of insulating portions 129 (in this embodiment, four insulating portions 129a, 129b, 129d and 129e) separated from one straight line L1. The first straight line L1 is an imaginary straight line passing through the center C of the air electrode 114 and along the flow direction FD of the oxidant gas OG when viewed in the Z-axis direction.

During operation of the fuel cell stack 100, the temperature of the center side of the air electrode 114 in the air chamber 166 when viewed in the Z-axis direction tends to be higher than the temperature of the end side. Due to the occurrence of such a temperature gradient, the oxidizing gas OG is less likely to flow toward the center of the air electrode 114 in the air chamber 166 as viewed in the Z-axis direction, and more likely to flow toward the ends. Therefore, in a configuration in which the distance between the adjacent insulating portions 129 in the upstream insulating portion group G1 (129a, . Non-uniformity in flow and gas flow at the edges degrades the electrical performance of the fuel cell stack 100 .

In contrast, in the fuel cell stack 100 of the present embodiment, as described above, the distance (I12, I13) is larger than the interval (I11, I14) between the adjacent insulating portions 129 in the end group G12. With such a configuration, compared to the configuration in which the intervals between the adjacent insulating portions 129 in the upstream side insulating portion group G1 (129a, . . . , 129e) are uniform, the air chamber 166 The gas flow at the center side of the air electrode 114 and the gas flow at the end sides are uniform. Therefore, according to the fuel cell stack 100 of the present embodiment, deterioration of the electrical performance of the fuel cell stack 100 can be suppressed.

Further, in the fuel cell stack 100 of the present embodiment, when viewed in the Z-axis direction, the distance (I22, I23) between the adjacent insulating portions 129 in the central group G21 of the downstream insulating portion group G2 is It is larger than the spacing (I21, I24) between adjacent insulating portions 129 in G22. The central side group G21 is formed by a plurality of insulating portions 129 (three insulating portions 129g, 129h, 129i in this embodiment) included in the downstream side insulating portion group G2 (129f, . . . , 129j). It is the group that is constructed. The end side group G22 is a plurality of insulating portions 129 included in the downstream side insulating portion group G2 (129f, . It is a group composed of a plurality of insulating portions 129 (in this embodiment, four insulating portions 129f, 129g, 129i and 129j) separated from one straight line L1.

In the fuel cell stack 100 of the present embodiment, for the same reason as in the upstream insulating subgroup G1 described above, adjacent insulating portions in the downstream insulating subgroup G2 (129a, . . . , 129e) Compared to the uniform spacing configuration of 129, the gas flow in the air chamber 166 on the center side of the cathode 114 and the gas flow on the edge side are uniform. Therefore, according to the fuel cell stack 100 of the present embodiment, deterioration of the electrical performance of the fuel cell stack 100 can be suppressed more effectively.

From the viewpoint of uniforming the gas flow on the central side of the air electrode 114 in the air chamber 166 and the gas flow on the end side, the adjacent insulating portions in the central side group G11 of the upstream side insulating subgroup G1 The intervals (I22, I23) between the insulating portions 129 are preferably 120% or more, more preferably 150% or more, of the intervals (I21, I24) between the adjacent insulating portions 129 in the end group G12. The same applies to the central side group G21 and the end side group G22 of the downstream side insulating partial group G2.

Further, in the fuel cell stack 100 of the present embodiment, in a cross section along the Z-axis direction (for example, the cross section shown in FIGS. 4 and 5), the single cell separator 120 includes a first separator inner peripheral portion 122. It has an inner portion 126 , 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 . The connecting portion 128 protrudes in the Z-axis direction with respect to both the inner portion 126 and the outer portion 127 .

In the fuel cell stack 100 of the present embodiment, the single cell separator 120 is configured to include the inner portion 126, the outer portion 127, and the connecting portion 128 described above, so that the distance between the single cell 110 and the interconnector 190 is likely to become shorter. Therefore, the present invention including the plurality of insulating portions 129 described above is particularly suitable for the fuel cell stack 100 of this embodiment having such a configuration.

In addition, the fuel cell stack 100 of this embodiment includes an interconnector separator 180, and an upper end plate 104 and a lower end plate 106 (a pair of end members) positioned on both sides of the power generation block 103 in the Z-axis direction. , bolts 22 and nuts 24 (fastening members) for fastening the power generation block 103 . The interconnector separator 180 has a substantially plate shape and is formed with a second separator through-hole 181 penetrating in the Z-axis direction. A second separator inner peripheral portion 182 (a portion surrounding the second separator through-hole 181 ) of the interconnector separator 180 is connected to the outer peripheral portion of the interconnector 190 . The upper end plate 104 and the lower end plate 106 (a pair of end members) are positioned on both sides of the power generation block 103 in the Z-axis direction. The bolt 22 (fastening member) is inserted into the communication hole 108 passing through the unit cell separator 120 , the interconnector separator 180 , the upper end plate 104 and the lower end plate 106 in the Z-axis direction, and fastens the power generation block 103 . have concluded.

The fuel cell stack 100 of this embodiment includes the above-described interconnector separator 180, the upper end plate 104 and the lower end plate 106 (a pair of end members), and the bolts 22 and nuts 24 (fastening members). As a result, deformation that shortens the distance between the unit cell 110 and the interconnector 190 is likely to occur. Therefore, the present invention including the plurality of insulating portions 129 described above is particularly suitable for the fuel cell stack 100 of this embodiment having such a configuration.

Moreover, in the fuel cell stack 100 of the present embodiment, the insulating portion 129 is made of glass. Therefore, according to the fuel cell stack 100 of the present embodiment, good insulation of the insulating portion 129 can be stably ensured even when used in a high-temperature environment.

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-described 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 other materials.

In addition, in the above-described embodiment (or modified examples, the same applies hereinafter), the shape and dimensions of the insulating portion 129 can be variously modified. Also, the number of insulating portions 129 may be changed. In addition, the distance between adjacent insulating portions 129 can also be varied.

Further, in the above embodiment, the insulating portion 129 may be made of ceramic.

Moreover, in the above-described embodiment, the plurality of insulating portions 129 do not need to be members independent of each other, and may be configured to be connected by a connecting portion that connects them to each other. Therefore, for example, in the above embodiment, the five insulating portions 129 (129a, . A configuration having a rod-shaped connecting portion arranged on the surface of the insulating portion 129 and connecting five insulating portions 129 (129a, . . . , 129e) may be employed.

Further, in the above-described embodiment, the insulating portion 129 may be arranged at a place other than the upper surface of the first separator inner peripheral portion 122, and is positioned inside the glass seal portion 125 when viewed in the Z-axis direction. It may be in contact with the glass seal portion 125 .

In the above embodiment, the insulating portion 129 includes a portion overlapping the first separator inner peripheral portion 122 and the interconnector 190 and a portion overlapping the first separator inner peripheral portion 122 and the interconnector 190 when viewed in the Z-axis direction. It may be a configuration having both a portion that does not overlap with.

In the above embodiment, the insulating portion 129 may have a portion overlapping the unit cell 110 and a portion not overlapping the unit cell 110 when viewed in the Z-axis direction.

Further, in the above embodiment, the fuel cell stack 100 may include only one of the upstream insulating subgroup G1 and the downstream insulating subgroup G2.

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 electrolysis cell stacks comprising a plurality of electrolysis single cells, which are the building blocks of a solid oxide electrolysis 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: 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 facing portion 47: connecting portion : Connection member 48a: Connection member 49: Elastic portion 50: Cover member 58: Upper specific space 60: Cover separator 61: Hole 66: Inner portion 67: Outer portion 68: Connecting portion 70: Upper terminal plate 71: Hole 72: Fuel gas supply communication hole 78: Protrusion 80: Lower terminal plate 81: Hole 82: Fuel gas supply communication hole 88: Protrusion 92: Upper insulating sheet 94: Hole 96: Lower insulating sheet 100: Fuel cell stack 102: Power generation unit 102X: Upper specific power generation unit 103: Power generation block 104: Upper end plate 106: Lower end plate 108: Communication hole 110: Single cell 112: Electrolyte layer 114: Air electrode 116: Fuel electrode 118: Intermediate layer 120: Single Cell Separator 121: Hole 124: Joint 125: Glass seal portion 126: Inner portion 127: Outer portion 128: Connecting portion 129 (129a, ..., 129j): Insulating portion 130: Air electrode side frame 131: Hole 132: Oxidant gas supply passage 133: Oxidant gas discharge passage 134: Air electrode side current collector 140: Fuel electrode side frame 141: Hole 142: Fuel gas supply passage 143: Fuel gas discharge passage 144: Conductive Electrode part 145: Electrode facing part 146: Interconnector facing part 147: Connecting part 148: Fuel electrode side collector 149: Elastic part 150: Flat plate part 161: Oxidant gas supply manifold 162: Oxidant gas discharge manifold 166: Air Chamber 171: Fuel gas supply manifold 172: Fuel gas discharge manifold 176: Fuel chamber 180: Separator for IC 180X: Separator for uppermost IC 181: Hole 181X: Hole 186: Inner part 187: Outer part 188: Connecting part 190: Inter Connector 190X: Top Interconnector 190Y: Bottom Interconnector 194: Coating Layer 196: Conductive Joining Material 211: Welding Portion 211a: Welding Part 212: Welded part 212a: Welded part 221: Welded part 221a: Welded part 222: Welded part 222a: Welded part 231: Welded part 232: Welded part 241: Welded part 270: Upper terminal unit C: Center of air electrode 114 FG : fuel gas FOG: fuel off-gas L1: first straight line OG: oxidant gas OOG: oxidant off-gas

Claims (7)

a unit cell comprising an electrolyte layer, an air electrode arranged on one side of the electrolyte layer in the first direction, and a fuel electrode arranged on the other side of the electrolyte layer in the first direction;
an interconnector arranged on the one side of the air electrode and electrically connected to the air electrode;
A single-cell separator having a substantially plate shape and having first separator through-holes penetrating in the first direction, wherein the first separator is a portion surrounding the first separator through-holes. a single cell separator having an inner peripheral portion positioned between the electrolyte layer and the interconnector and joined to the single cell ;
each comprising an electrochemical reaction block composed of a plurality of electrochemical reaction units arranged side by side in the first direction,
having a portion located between the first separator inner peripheral portion and the interconnector and overlapping the first separator inner peripheral portion and the interconnector when viewed in the first direction; and A plurality of insulating portions having a portion overlapping with the unit cell when viewed in the first direction , wherein the plurality of insulating portions are arranged while being separated from each other along the circumferential direction of the inner peripheral portion of the first separator. comprising a part
An electrochemical reaction cell stack characterized by: The electrochemical reaction cell stack according to claim 1,
the entirety of the at least one insulating portion overlaps the single cell when viewed in the first direction;
An electrochemical reaction cell stack characterized by: The electrochemical reaction cell stack according to claim 1 or claim 2,
When viewed in the first direction, the plurality of insulating portions are arranged along a second direction that intersects the direction of gas flow in the air chamber facing the air electrode. An upstream insulating portion group positioned upstream of the air electrode and a plurality of the insulating portions arranged along the second direction, and located downstream of the air electrode in the direction of gas flow. at least one of a downstream insulating subgroup located at
An electrochemical reaction cell stack characterized by: The electrochemical reaction cell stack according to claim 3,
When viewed from the first direction,
When an imaginary straight line passing through the center of the air electrode and along the flow direction of the gas is defined as a first straight line,
Adjacent insulating properties in a central side group composed of a plurality of the insulating portions included in a specific insulating portion group that is at least one of the upstream side insulating portion group and the downstream side insulating portion group The distance between the portions is determined by any of the plurality of the insulating portions included in the specific insulating portion group, the plurality of the insulating portions being farther from the first straight line than the central side group. greater than the spacing between adjacent insulating portions in the end group to be constructed,
An electrochemical reaction cell stack characterized by: An electrochemical reaction cell stack according to any one of claims 1 to 4,
In a specific cross section that is at least one cross section along the first direction,
The single cell separator is
an inner portion including the first separator inner peripheral portion;
an outer portion located on the outer peripheral side of the inner portion;
a connecting portion that connects the inner portion and the outer portion and protrudes in the first direction with respect to both the inner portion and the outer portion;
comprising
An electrochemical reaction cell stack characterized by: An electrochemical reaction cell stack according to any one of claims 1 to 5,
A separator for an interconnector having a substantially plate shape and having a second separator through-hole penetrating in the first direction, the second separator inner peripheral portion surrounding the second separator through-hole an interconnector separator connected to the outer periphery of the interconnector;
a pair of end members respectively positioned on both sides of the electrochemical reaction block in the first direction;
a fastening member that is inserted into the through-hole that penetrates the single cell separator, the interconnector separator, and the pair of end members in the first direction and that fastens the electrochemical reaction block;
An electrochemical reaction cell stack characterized by: An electrochemical reaction cell stack according to any one of claims 1 to 6,
The insulating portion is made of glass or ceramic,
An electrochemical reaction cell stack characterized by:

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