JP2019096457A - Electrochemical reaction unit and electrochemical reaction cell stack - Google Patents

Abstract

To improve both of an electrical connectivity between a collector and a unit cell and a gas diffusivity near a border between the collector and the unit cell.SOLUTION: An electrochemical reaction unit comprising a unit cell 110, a collector 144 and a spacer 149 is provided in which the collector 144 includes: a plurality of cell opposition parts 145 opposite to the unit cell 110; a base part arranged on one side of a first direction to each cell opposition part 145; and a connection part connecting the base part and each cell opposition part to each other. The spacer 149 is opposite to a front surface on one side in the first direction, of each cell opposition part 145, the collector 144 has constitution in which a metal wire is kitted in a mesh-like, and each cell opposition part 145 includes a flat surface in contact with the front surface of the unit cell and has a portion where a distance L1 to the front surface opposite to the unit cell 110 from the spacer 149 to each cell opposition part 145 in the first direction is shorter than a distance L2 from the spacer to the unit cell 110.SELECTED DRAWING: Figure 8

Description

  The technology disclosed by the present specification relates to an electrochemical reaction unit.

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

  In addition, the power generation unit includes a current collector (for example, a fuel electrode side current collector) disposed on one side (for example, the fuel electrode side) of the first cell with respect to the unit cell. The current collector is a member for extracting electric power generated by a power generation reaction in a single cell. As a configuration of the current collector, a plurality of cell facing portions facing a single cell, a base disposed on one side in the first direction with respect to each cell facing portion, a base and each cell facing portion are connected A configuration including a connection portion is known (see, for example, Patent Document 1). Further, in the configuration of the current collector, by providing a spacer facing the surface on one side in the first direction of each cell facing portion, electricity between each cell facing portion of the current collector and the single cell is provided. Techniques are well known to maintain a positive connection.

JP, 2013-55042, A

  In the power generation unit including the current collector having the above-described conventional configuration, the current collector inhibits the flow of gas, so that the gas diffusivity in the vicinity of the boundary between the current collector and the single cell decreases, and the single cell performance is improved. It may decrease. Thus, in the power generation unit of the conventional configuration, it is possible to simultaneously improve the electrical connectivity between the current collector and the single cell and the gas diffusivity near the boundary between the current collector and the single cell. In terms of points, there is room for improvement.

  In addition, such a subject is a subject common to the electrolytic cell unit which is a structural unit of a solid oxide electrolytic cell (hereinafter referred to as "SOEC") which generates hydrogen by utilizing the electrolysis reaction of water. It is. In the present specification, the fuel cell power generation unit and the electrolysis cell unit are collectively referred to as an electrochemical reaction unit.

  The present specification discloses a technology that can solve the above-described problems.

  The technology disclosed in the present specification can be realized, for example, as the following form.

(1) The electrochemical reaction unit disclosed in the present specification includes a unit cell including an electrolyte layer and an air electrode and a fuel electrode facing each other in the first direction with the electrolyte layer interposed therebetween, and the unit cell A current collector disposed on one side of the first direction with respect to the plurality of cell opposing portions facing the single cell, and the first direction relative to each cell opposing portion A collector including a base disposed on one side, and a connecting part connecting the base and the cell facing parts, and the surface on the one side of the cell facing parts in the first direction In the electrochemical reaction unit provided with a facing spacer, the current collector has a configuration in which a metal wire is knitted in a mesh shape, and at least a part of the cell facing portion is a surface of the single cell. The flat surface in contact with the surface, and in the first direction Distance L1 from Sir to the surface opposed to the single cells in the cell counter unit is shorter portions than the distance L2 from the spacer to the single cell exists. In this electrochemical reaction unit, the cell facing portion has a flat surface in contact with the surface of the single cell, and the distance from the spacer to the surface facing the single cell in the cell facing portion in the first direction There is a place where L1 is shorter than the distance L2 from the spacer to the single cell. Therefore, in the present electrochemical reaction unit, the contact area between the cell facing portion of the current collector and the single cell is increased, and a space is formed between the cell facing portion of the current collector and the single cell. Therefore, according to the present electrochemical reaction unit, it is possible to improve the electrical connectivity between the current collector and the single cell, and to increase the gas diffusivity near the boundary between the current collector and the single cell. As a result, the performance of the electrochemical reaction unit can be improved.

(2) In the electrochemical reaction unit, the minimum diameter of the wire at the position of the flat surface may be 1/2 or more of the maximum diameter of the wire at a position other than the flat surface. In the present electrochemical reaction unit, the wire is not excessively crushed at the flat surface position. Therefore, according to the present electrochemical reaction unit, a space for gas diffusion can be effectively secured near the boundary between the current collector and the single cell, and the space between the current collector and the single cell can be obtained. Gas diffusivity in the vicinity of the boundary can be effectively improved.

(3) In the electrochemical reaction unit, the width W1 of the flat surface of the one wire is the width of the one wire in the direction orthogonal to the extending direction of the one wire in the first direction view. It may be configured to have a width W2 or less at a position other than the flat surface. In the present electrochemical reaction unit, the wire is not excessively crushed at the flat surface position. Therefore, according to the present electrochemical reaction unit, a space for gas diffusion can be effectively secured near the boundary between the current collector and the single cell, and the space between the current collector and the single cell can be obtained. Gas diffusivity in the vicinity of the boundary can be effectively improved.

(4) In the electrochemical reaction unit, the width W3 of the flat surface of the one wire intersects the one wire in the extending direction of the one wire in the first direction view. It may be configured to be larger than the width W4 at a position other than the flat surface of the wire. In the present electrochemical reaction unit, the wire is crushed to a certain extent or more at the position of the flat surface. Therefore, according to the present electrochemical reaction unit, the size of the flat surface can be set to a certain size or more, and the contact area between the cell facing portion of the current collector and the single cell can be effectively enlarged. As a result, the electrical connectivity between the current collector and the single cell can be effectively improved.

(5) In the electrochemical reaction unit, in a cross section parallel to both the extending direction of one of the wires and the first direction, two adjacent ones in the second direction orthogonal to the first direction The ratio of the width W6 of the specific area satisfying the condition that the distance L1 is shorter than the distance L2 in the area to the width W5 of the area sandwiched by the center positions of the flat surfaces is 0.8 or more It may be In the present electrochemical reaction unit, a specific region satisfying the condition that the distance L1 is shorter than the distance L2 is present to a certain extent or more. Therefore, according to the present electrochemical reaction unit, a space for gas diffusion can be effectively secured near the boundary between the current collector and the single cell, and the space between the current collector and the single cell can be obtained. Gas diffusivity in the vicinity of the boundary can be effectively improved.

(6) In the electrochemical reaction unit, the cell facing portion may not have a flat surface on the side facing the spacer. According to the present electrochemical reaction unit, a space for gas diffusion can be more effectively secured near the boundary between the current collector and the single cell, and the boundary between the current collector and the single cell Gas diffusivity in the vicinity can be further improved effectively.

(7) In the electrochemical reaction unit, in the first direction, the distance L3 from the unit cell to the surface facing the spacer in the cell facing portion is shorter than the distance L2 from the spacer to the unit cell It is good also as composition which a part exists. According to the present electrochemical reaction unit, since a space is formed between the cell facing portion of the current collector and the spacer, it is possible to improve the gas diffusivity in the vicinity of the boundary between the current collector and the spacer. As a result, the performance of the electrochemical reaction unit can be improved.

(8) In the electrochemical reaction unit, the unit cell may be a fuel cell unit cell. According to the present electrochemical reaction unit, it is possible to improve the electrical connectivity between the current collector and the single fuel cell, and to diffuse the gas near the boundary between the current collector and the single fuel cell. As a result, the power generation performance of the electrochemical reaction unit can be improved.

  The technology disclosed herein can be realized in various forms, for example, an electrochemical reaction unit (a fuel cell power generation unit or an electrolysis cell unit), and an electricity provided with a plurality of electrochemical reaction units. It is possible to realize in the form of a chemical reaction cell stack (fuel cell stack or electrolysis cell stack), a method of manufacturing them, and the like.

It is a perspective view showing the appearance composition of fuel cell stack 100 in an embodiment. It is explanatory drawing which shows the XZ cross-section structure of the fuel cell stack 100 in the position of II-II of FIG. It is explanatory drawing which shows YZ cross-section structure of the fuel cell stack 100 in the position of III-III of FIG. It is explanatory drawing which shows the XZ cross-section structure of the two adjacent electric power generation units 102 in the same position as the cross section shown in FIG. It is explanatory drawing which shows YZ cross-section structure of the two adjacent electric power generation units 102 in the same position as the cross section shown in FIG. It is explanatory drawing which shows XY sectional structure of the electric power generation unit 102 in the position of VI-VI of FIG. It is explanatory drawing which shows XY sectional structure of the electric power generation unit 102 in the position of VII-VII of FIG. FIG. 7 is an explanatory view showing a detailed configuration of a fuel electrode side current collector 144. It is a perspective view which shows the detailed structure of the cell opposing part 145 of the fuel electrode side collector 144. FIG. It is a perspective view which shows the detailed structure of the cell opposing part 145 of the fuel electrode side collector 144. FIG. It is explanatory drawing which shows the structure of the fuel electrode side collector 144X in a 1st comparative example. It is an explanatory view showing the composition of fuel electrode side current collection object 144Y in the 2nd comparative example. It is an explanatory view showing the composition of fuel electrode side current collection object 144a in a modification.

A. Embodiment:
A-1. Constitution:
(Configuration of fuel cell stack 100)
FIG. 1 is a perspective view showing an appearance configuration of a fuel cell stack 100 in the embodiment, and FIG. 2 is an XZ cross section of the fuel cell stack 100 at a position II-II in FIG. 1 (and FIGS. FIG. 3 is an explanatory view showing a configuration, and FIG. 3 is an explanatory view showing a YZ cross-sectional configuration of a fuel cell stack 100 at a position of III-III in FIG. 1 (and FIGS. 6 and 7 described later). In each figure, mutually orthogonal XYZ axes for specifying the direction are shown. In this specification, for convenience, the Z-axis positive direction is referred to as the upward direction, and the Z-axis negative direction is referred to as the downward direction. However, the fuel cell stack 100 actually has an orientation different from such an orientation. It may be installed. The same applies to FIG.

  The fuel cell stack 100 includes a plurality of (seven in the present embodiment) fuel cell power generation units (hereinafter simply referred to as “power generation units”) 102 and a pair of end plates 104 and 106. The seven power generation units 102 are arranged in a predetermined arrangement direction (vertical direction in the present embodiment). The pair of end plates 104 and 106 are arranged to sandwich an assembly composed of seven power generation units 102 from above and below. The arrangement direction (vertical direction) corresponds to the first direction in the claims.

  A plurality of (eight in the present embodiment) holes are formed in the peripheral portion around the Z direction of each layer (power generation unit 102, end plates 104 and 106) constituting the fuel cell stack 100. The holes formed in each layer and corresponding to each other communicate with each other in the vertical direction, and form communication holes 108 extending in the vertical direction from one end plate 104 to the other end plate 106. In the following description, 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 into each communication hole 108, and the fuel cell stack 100 is fastened by the bolt 22 and nuts 24 fitted on both sides of the bolt 22. As shown in FIGS. 2 and 3, between the nut 24 fitted on one side (upper side) of the bolt 22 and the upper surface of the end plate 104 constituting the upper end of the fuel cell stack 100, and the bolt An insulating sheet 26 is interposed between the nut 24 fitted on the other side (lower side) of the electrode 22 and the lower surface of the end plate 106 constituting the lower end of the fuel cell stack 100. However, at the places where the gas passage members 27 described later are provided, insulating sheets disposed on the upper and lower sides of the gas passage members 27 and the gas passage members 27 between the nut 24 and the surface of the end plate 106, respectively. 26 and so on. The insulating sheet 26 is made of, for example, a mica sheet, a ceramic fiber sheet, a ceramic dust sheet, a glass sheet, a glass ceramic composite agent, or the like.

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

  Further, as shown in FIGS. 1 and 3, the vicinity of the middle point of one side (the side on the Y-axis positive direction side of the two sides parallel to the X-axis) on the outer periphery of the fuel cell stack 100 around the Z direction. The fuel gas FG is introduced from the outside of the fuel cell stack 100 in the space formed by the bolt 22 (bolt 22D) located in the space and the communication hole 108 through which the bolt 22D is inserted. A bolt 22 functioning as a fuel gas introduction manifold 171 supplying to the unit 102 and located near the middle point of the opposite side of the side (the side of the two sides parallel to the X-axis in the negative Y-axis direction) A space formed by (the bolt 22E) and the communication hole 108 through which the bolt 22E is inserted is a fuel off gas FOG which is a gas discharged from the fuel chamber 176 of each power generation unit 102 as the fuel cell stack 1 Functions as a fuel gas exhaust manifold 172 for discharging to the outside of the 0. In the present embodiment, a hydrogen rich gas obtained by reforming city gas, for example, is used as the fuel gas FG.

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

(Configuration of end plates 104 and 106)
The pair of end plates 104 and 106 is a substantially rectangular flat conductive member and is made of, for example, stainless steel. One end plate 104 is disposed on the upper side of the uppermost power generation unit 102, and the other end plate 106 is disposed on the lower side of the lowermost power generation unit 102. The plurality of power generation units 102 are held in a pressed state by the pair of end plates 104 and 106. The upper end plate 104 functions as a positive output terminal of the fuel cell stack 100, and the lower end plate 106 functions as a negative output terminal of the fuel cell stack 100.

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

  As shown in FIGS. 4 and 5, the power generation unit 102 includes the unit cell 110, the separator 120, the air electrode side frame 130, the air electrode side current collector 134, the fuel electrode side frame 140, and the fuel electrode side. A current collector 144 and a pair of interconnectors 150 constituting the top layer and the bottom layer of the power generation unit 102 are provided. In the peripheral portion around the Z direction in the separator 120, the air electrode side frame 130, the fuel electrode side frame 140, and the interconnector 150, holes corresponding to the communication holes 108 through which the above-described bolts 22 are inserted are formed.

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

  The unit cell 110 includes an electrolyte layer 112, and an air electrode (cathode) 114 and a fuel electrode (anode) 116 facing each other in the vertical direction (first direction) with the electrolyte layer 112 interposed therebetween, the electrolyte layer 112 and the air electrode 114. And an intermediate layer 180 disposed therebetween. The unit cell 110 of this embodiment is a unit cell of the fuel electrode support type that supports the other layers (the electrolyte layer 112, the air electrode 114, and the intermediate layer 180) constituting the unit cell 110 with the fuel electrode 116.

  The electrolyte layer 112 is a flat plate-shaped member having a substantially rectangular shape in the Z-axis direction, and is a dense (low porosity) layer. The electrolyte layer 112 is formed of, for example, a solid oxide such as YSZ (yttria stabilized zirconia). Thus, the unit cell 110 (power generation unit 102) of the present embodiment is a solid oxide fuel cell (SOFC) using a solid oxide as an electrolyte.

  The air electrode 114 is a substantially rectangular flat plate-shaped member smaller than the electrolyte layer 112 in the Z-axis direction, and is a porous layer (having a higher porosity than the electrolyte layer 112). The air electrode 114 is made of, for example, a perovskite type oxide (for example, LSCF (lanthanum strontium cobalt iron oxide), LSM (lanthanum strontium manganese oxide), LNF (lanthanum nickel iron)).

  The fuel electrode 116 is a substantially rectangular flat plate shaped member having substantially the same size as the electrolyte layer 112 in the Z-axis direction, and is a porous layer. The fuel electrode 116 is formed of, for example, a cermet composed of Ni and oxide ion conductive ceramic particles (for example, YSZ).

The intermediate layer 180 is a substantially rectangular flat-shaped member, and is formed to include GDC (gadolinium-doped ceria). In the intermediate layer 180, an element (for example, Sr) diffused from the air electrode 114 reacts with an element (for example, Zr) contained in the electrolyte layer 112 to generate a high-resistance substance (for example, SrZrO ₃ ). Suppress.

  The separator 120 is a frame-shaped member in which a substantially rectangular hole 121 penetrating in the vertical direction is formed in the vicinity of the center, and is formed of, for example, metal. The peripheral portion of the hole 121 in the separator 120 faces the peripheral portion of the surface of the electrolyte layer 112 on the air electrode 114 side. The separator 120 is bonded to the electrolyte layer 112 (unit cell 110) by a bonding portion 124 formed of a brazing material (for example, Ag wax) disposed in the facing portion. The air chamber 166 facing the air electrode 114 and the fuel chamber 176 facing the fuel electrode 116 are separated by the separator 120, and the gas leaks from the one electrode side to the other electrode side in the peripheral portion of the unit cell 110. Be suppressed.

  As shown in FIGS. 4 to 6, the air electrode side frame 130 is a frame-like member in which a substantially rectangular hole 131 penetrating in the vertical direction is formed near the center, and is formed of an insulator such as mica, for example. ing. The hole 131 of the air electrode side frame 130 constitutes an air chamber 166 facing the air electrode 114. The air electrode side frame 130 is in contact with the peripheral portion of the surface of the separator 120 opposite to the side facing the electrolyte layer 112 and the peripheral portion of the surface of the interconnector 150 facing the air electrode 114. . Further, the air electrode side frame 130 electrically insulates between the pair of interconnectors 150 included in the power generation unit 102. Further, an oxidant gas supply passage 132 communicating the oxidant gas introduction manifold 161 with the air chamber 166, and an oxidant gas communicating the air chamber 166 with the oxidant gas discharge manifold 162 in the air electrode side frame 130. A discharge communication hole 133 is formed.

  As shown in FIGS. 4, 5 and 7, the fuel electrode side frame 140 is a frame-like member in which a substantially rectangular hole 141 penetrating in the vertical direction is formed in the vicinity of the center, and is made of metal, for example. . The hole 141 of the fuel electrode side frame 140 constitutes a fuel chamber 176 facing the fuel electrode 116. The fuel electrode side frame 140 is in contact with the peripheral portion of the surface of the separator 120 facing the electrolyte layer 112 and the peripheral portion of the surface of the interconnector 150 facing the fuel electrode 116. Further, in the fuel electrode side frame 140, a fuel gas supply passage 142 communicating the fuel gas introduction manifold 171 with the fuel chamber 176, and a fuel gas discharge passage 143 communicating the fuel chamber 176 with the fuel gas discharge manifold 172. And are formed.

  As shown in FIGS. 4, 5 and 7, the fuel electrode side current collector 144 is disposed below the unit cell 110. The fuel electrode side current collector 144 includes a base portion 146, a plurality of cell facing portions 145, and a connecting portion 147 connecting the cell facing portions 145 and the base portion 146. For example, a metal such as nickel or nickel alloy It is formed by As shown in the partial enlarged view in FIG. 7, the fuel electrode side current collector 144 is manufactured by cutting a flat plate member (in the present embodiment, a metal mesh) and processing a plurality of portions to be bent and raised. . Each portion bent and bent becomes a cell facing portion 145, and a flat plate portion with holes OP opened other than the bent portion becomes a base 146 and a portion connecting the cell facing portion 145 and the base 146 is a connecting portion 147 Become. Note that, in the partially enlarged view in FIG. 7, in order to show the manufacturing method of the fuel electrode side current collector 144, a state before bending and raising processing is completed is shown for a part of the portion to be bent and raised.

  The cell facing portion 145 of the fuel electrode side current collector 144 faces the surface (lower surface) of the fuel electrode 116 opposite to the side facing the electrolyte layer 112 and is in contact with the surface. The base portion 146 is disposed on the lower side with respect to each cell facing portion 145, and is in contact with the surface (upper surface) of the interconnector 150 on the side facing the fuel electrode 116. However, as described above, since the lowermost power generation unit 102 in the fuel cell stack 100 does not have the lower interconnector 150, the base 146 of the power generation unit 102 contacts the lower end plate 106. doing. The fuel electrode side current collector 144 electrically connects the fuel electrode 116 and the interconnector 150 (or the end plate 106) because of such a configuration. The lower side corresponds to one side in the first direction in the claims, and the fuel electrode side current collector 144 corresponds to the current collector in the claims. The configuration of the fuel electrode side current collector 144 will be described in detail later.

  Further, a spacer 149 formed of, for example, mica is disposed between each cell facing portion 145 and the base 146 of the fuel electrode side current collector 144. The spacer 149 faces the lower surface of each cell facing portion 145 and is in contact with the surface. Due to the presence of the spacer 149, the fuel electrode side current collector 144 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 150 (or the fuel electrode side current collector 144) The electrical connection with the end plate 106) is well maintained.

  As shown in FIGS. 4 to 6, the air electrode side current collector 134 is disposed in the air chamber 166. The air electrode side current collector 134 is composed of a plurality of substantially square pole shaped current collector elements 135, and is made of, for example, ferritic stainless steel. The air electrode side current collector 134 is in contact with the surface of the air electrode 114 opposite to the side facing the electrolyte layer 112 and the surface of the interconnector 150 opposite to the air electrode 114. However, as described above, since the power generation unit 102 positioned at the top in the fuel cell stack 100 does not have the upper interconnector 150, the air electrode side current collector 134 in the power generation unit 102 is the upper end plate It is in contact with 104. Because of such a configuration, the air electrode side current collector 134 electrically connects the air electrode 114 and the interconnector 150 (or the end plate 104).

  In the present embodiment, the air electrode side current collector 134 (the current collector element 135) and the interconnector 150 are formed as an integral member. That is, of the integral members, a flat plate-shaped portion orthogonal to the vertical direction (Z-axis direction) functions as the interconnector 150, and is formed to project from the flat-plate portion toward the air electrode 114. The plurality of current collector elements 135 function as the air electrode side current collector 134.

Also, as shown in FIGS. 4 and 5, the surface of the air electrode side current collector 134 (the current collector element 135) is covered with a conductive coat 136. The coat 136 is formed of, for example, a spinel type oxide (eg, Mn _1.5 Co _1.5 O ₄ , MnCo ₂ O ₄ , ZnCo ₂ O ₄ , ZnMn ₂ O ₄ , ZnMnCoO ₄ , CuMn ₂ O ₄ ) ing. As described above, in the present embodiment, since the air electrode side current collector 134 (the current collector element 135) and the interconnector 150 are formed as an integral member, the air electrode side current collector 134 is actually formed. Among the surfaces of the current collector 134 (current collector element 135), the interface with the interconnector 150 is not covered by the coat 136, while the surface of the interconnector 150 is a gas flow path through which at least the oxidant gas OG flows. The surface facing (for example, the surface on the air electrode 114 side in the interconnector 150) is covered by a coat 136. In the following description, the air electrode side current collector 134 (the current collector element 135) means "the air electrode side current collector 134 covered by the coat 136 (the current collector element 135)" unless otherwise specified. In FIG. 6, the coat 136 is not shown.

Further, as shown in FIGS. 4 and 5, the air electrode 114 and the air electrode side current collector 134 (the current collector element 135) are bonded by the bonding layer 138 having conductivity. The bonding layer 138 is formed of, for example, a spinel-type oxide (eg, Mn _1.5 Co _1.5 O ₄ , MnCo ₂ O ₄ , ZnCo ₂ O ₄ , ZnMn ₂ O ₄ , ZnMnCoO ₄ , CuMn ₂ O ₄ ) It is done. The bonding layer 138 electrically connects the air electrode 114 and the air electrode side current collector 134. Although the air electrode side current collector 134 was described earlier as being in contact with the surface of the air electrode 114, exactly, the bonding layer 138 exists between the air electrode side current collector 134 and the air electrode 114. It intervenes.

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 introduction manifold 161. Then, the oxidant gas OG is supplied to the oxidant gas introduction manifold 161 through the holes of the branch part 29 and the main body part 28 of the gas passage member 27, and the oxidant gas introduction manifold 161 oxidizes each power generation unit 102. The air is supplied to the air chamber 166 through the agent gas supply passage 132. Further, as shown in FIGS. 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 introduction manifold 171. Then, the fuel gas FG is supplied to the fuel gas introduction manifold 171 through the branch portion 29 of the gas passage member 27 and the hole of the main body portion 28, and the fuel gas supply communication of each power generation unit 102 from the fuel gas introduction manifold 171. The fuel is supplied to the fuel chamber 176 through the hole 142.

  When the oxidant gas OG is supplied to the air chamber 166 of each power generation unit 102 and the fuel gas FG is supplied to the fuel chamber 176, the single cell 110 performs power generation by the electrochemical reaction of the oxidant gas OG and the fuel gas FG. It will be. This power generation reaction is an exothermic reaction. In each power generation unit 102, the air electrode 114 of the unit cell 110 is electrically connected to the air electrode side current collector 134, and the fuel electrode 116 is electrically connected to the interconnector 150 via the fuel electrode side current collector 144. It is done. Also, the plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. Therefore, the electrical energy generated in each power generation unit 102 is taken out from the end plates 104 and 106 functioning as the output terminals of the fuel cell stack 100. Since the SOFC generates power at a relatively high temperature (eg, 700 ° C. to 1000 ° C.), the fuel cell stack 100 is heated (after start-up, until the heat can be maintained by the heat generated by the power generation). (Not shown).

  The oxidant off gas OOG discharged from the air chamber 166 of each power generation unit 102 is discharged to the oxidant gas discharge manifold 162 through the oxidant gas discharge communication hole 133 and further oxidized as shown in FIGS. 2 and 4. The fuel cell stack 100 is provided through the holes of the main body portion 28 of the gas passage member 27 and the branch portion 29 provided at the position of the agent gas discharge manifold 162 and the gas pipe (not shown) connected to the branch portion 29. Discharged to the outside of the Further, as shown in FIGS. 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 the fuel gas To the outside of the fuel cell stack 100 through a gas pipe (not shown) connected to the branch portion 29 through the holes of the main body portion 28 of the gas passage member 27 and the branch portion 29 provided at the position of the discharge manifold 172 Exhausted.

A-3. Detailed configuration of fuel electrode side current collector 144:
Next, the configuration of the fuel electrode side current collector 144 will be described in more detail. FIG. 8 is an explanatory view showing a detailed configuration of the fuel electrode side current collector 144. As shown in FIG. FIG. 8 is an enlarged view of the XZ cross-sectional configuration of the X1 portion of FIG. 9 and 10 are perspective views showing a detailed configuration of the cell facing portion 145 of the fuel electrode side current collector 144. As shown in FIG.

  As shown in FIG. 8 to FIG. 10, the fuel electrode side current collector 144 has a configuration in which metal wires (for example, made of nickel or nickel alloy) 210 and 220 are meshed in a mesh shape (hatched eye configuration) Have. More specifically, the fuel electrode side current collector 144 includes a plurality of wires (hereinafter referred to as “horizontal wires”) 210 extending in substantially one direction (in the present embodiment, in the X-axis direction in the cell facing portion 145). A plurality of wires (hereinafter, referred to as “longitudinal wires”) 220 extend in the other direction (in the present embodiment, in the Y-axis direction in the cell facing portion 145 in the present embodiment) substantially intersecting the one direction. Longitudinal wires 220 are alternately arranged on the upper and lower sides of the respective horizontal wires 210 along the extending direction of the respective horizontal wires 210, and along the extending direction of the respective longitudinal wires 220, the respective vertical wires 220. Horizontal wires 210 are alternately arranged one by one on the upper side and the lower side of. Such a configuration of the fuel electrode side current collector 144 is realized by processing a metal mesh to produce the fuel electrode side current collector 144 as described above.

  The horizontal wire 210 and the vertical wire 220 which constitute the anode side current collector 144 are wires of a substantially circular cross section. However, in the cell facing portion 145 of the fuel electrode side current collector 144, the flat surface 212 is formed on the upper side (the side facing the single cell 110) in a portion of each horizontal wire 210, and A flat surface 222 is also formed on the upper side of a portion. These flat surfaces 212 and 222 are in contact with the surface of the unit cell 110 (fuel electrode 116). On the other hand, in the cell facing portion 145 of the fuel electrode side current collector 144, no flat surface is formed on the lower side (side facing the spacer 149) of each horizontal wire 210, and the lower side of each vertical wire 220. There is no flat surface on the side. Therefore, the contact points 214 with the spacers 149 in the horizontal wires 210 and the contact points 224 with the spacers 149 in the longitudinal wires 220 are both linear. As described above, in the present embodiment, the cell facing portion 145 of the fuel electrode side current collector 144 is in surface contact with the unit cell 110 (fuel electrode 116) and in linear contact with the spacer 149. When at least a part of the flat surfaces 212 and 222 of the cell facing portion 145 is in contact with the surface of the single cell 110, at least a part of the flat surfaces 212 and 222 of the cell facing portion 145 and the single cell 110 directly The flat surface 212 of the cell facing portion 145 is not limited to the form of contact but to such an extent that the space SP between the unit cell 110 and the cell facing portion 145 is not eliminated. , 222 and the single cell 110 indirectly contact with each other. That is, when at least a part of the flat surfaces 212 and 222 of the cell facing part 145 is in contact with the surface of the single cell 110, at least a part of the flat surfaces 212 and 222 directly or through other members. Indirectly, it means contacting the surface of the single cell 110.

  In the fuel electrode side current collector 144 having such a configuration, for example, a metal mesh which is a forming material of the fuel electrode side current collector 144 is subjected to roll press processing, and flat surfaces 212 and 222 are formed on the respective wires 210 and 220. It can be realized by forming (however, by laying a high elastic body on one side, the surfaces of the wires 210 and 220 facing the spacer 149 are not crushed).

  Further, as shown in FIG. 8, in the present embodiment, in the vertical direction (Z-axis direction), from the spacer 149 to the surface facing the unit cell 110 in the cell facing portion 145 (hereinafter also referred to as “upper surface”) There is a place where the distance L1 is shorter than the distance L2 from the spacer 149 to the single cell 110. That is, in the first position P1 where the flat surface 212 is formed in the horizontal wire 210 and in the second position P2 where the flat surface 222 is formed in the vertical wire 220, the spacer 149 to the upper surface of the cell facing portion 145 The distance L1 up to is equal to the distance L2 from the spacer 149 to the single cell 110. On the other hand, at the third position P3 where the flat surfaces 212 and 222 are not formed, the distance L1 from the spacer 149 to the upper surface of the cell facing portion 145 is shorter than the distance L2 from the spacer 149 to the unit cell 110. Since the cell facing portion 145 has such a configuration, a space SP is present between the cell facing portion 145 and the single cell 110.

  As described above, in the cell facing portion 145 of the fuel electrode side current collector 144, the flat surface is not formed on the lower side (the side facing the spacer 149) in each horizontal wire 210 and each vertical wire 220. Therefore, the space SP is also present between the cell facing portion 145 and the spacer 149.

  Further, as shown in FIG. 8, in the present embodiment, from the unit cell 110 to the surface facing the spacer 149 in the cell facing portion 145 in the vertical direction (Z-axis direction) (hereinafter, also referred to as “lower surface”) There is a portion where the distance L3 of the distance L3 is shorter than the distance L2 from the spacer 149 to the single cell 110. Since the cell facing portion 145 has such a configuration, it can be said that the space SP is present between the cell facing portion 145 and the spacer 149 also in this respect.

  Further, as shown in FIG. 8, in the present embodiment, the minimum diameter R1 of the transverse wire 210 at the position of the flat surface 212 is a position other than the flat surface 212 (more specifically, adjacent to a portion having the flat surface 212 And, it is 1/2 or more of the maximum diameter R0 of the horizontal wire 210 at a position where it is not in contact with either the unit cell 110 or the spacer 149 (the same applies to the following). Further, although not shown, the minimum diameter of the longitudinal wire 220 at the position of the flat surface 222 is also equal to or larger than half of the maximum diameter of the longitudinal wire 220 at a position other than the flat surface 222 in the same manner. . That is, the horizontal wires 210 and the vertical wires 220 are not excessively crushed at the places where the flat surfaces 212 and 222 are formed.

  Further, as shown in FIG. 9, in the present embodiment, the width of the flat surface 212 of the horizontal wire 210 in the direction (Y-axis direction) orthogonal to the extending direction (X-axis direction) of the horizontal wire 210 in the vertical direction. W1 is equal to or less than the width W2 at a position other than the flat surface 212 of the lateral wire 210. Although not shown, the width of the flat surface 222 of the vertical wire 220 in the direction (X-axis direction) perpendicular to the extension direction (Y-axis direction) of the vertical wire 220 in the vertical direction as well in the same manner. Is equal to or less than the width at a position other than the flat surface 222 of the longitudinal wire 220. That is, the horizontal wires 210 and the vertical wires 220 are not excessively crushed at the places where the flat surfaces 212 and 222 are formed.

  Further, as shown in FIG. 10, in the present embodiment, the width W3 of the flat surface 212 of the lateral wire 210 intersects the lateral wire 210 in the extension direction (X-axis direction) of the lateral wire 210 in the vertical direction. Is greater than the width W4 at positions other than the flat surface 222 of the longitudinal wire 220. Although not illustrated, the width of the flat surface 222 of the vertical wire 220 intersects the vertical wire 220 in the extension direction (Y-axis direction) of the vertical wire 220 in the vertical direction as well in the vertical direction. It is larger than the width at positions other than the flat surface 212 of the transverse wire 210. That is, the horizontal wire 210 and the vertical wire 220 are crushed to a certain extent or more at the places where the flat surfaces 212 and 222 are formed.

  Further, as shown in FIG. 8, in the present embodiment, in a cross section (XZ cross section) parallel to both the extension direction and the vertical direction of the horizontal wire 210, they are adjacent to each other in the direction (X axis direction) orthogonal to the vertical direction. The ratio of the width W6 of the specific region satisfying the condition that the distance L1 is shorter than the distance L2 in the region to the width W5 of the region sandwiched by the respective center positions of the two flat surfaces 212 and 222 that are matched is 0. 8 or more (80% or more). At this time, the X-axis direction corresponds to the second direction in the claims. Further, although not shown, similarly, in a cross section (YZ cross section) parallel to both the extension direction and the vertical direction of the longitudinal wire 220, two flat surfaces adjacent to each other in the direction (Y axis direction) orthogonal to the vertical direction The ratio of the width of the specific region satisfying the condition that the distance L1 is shorter than the distance L2 in the region to the width of the region sandwiched by the central positions of 212 and 222 is 0.8 or more (80% or more) It is. At this time, the Y-axis direction corresponds to the second direction in the claims. That is, for the horizontal wire 210 and the vertical wire 220, a specific region satisfying the condition that the distance L1 is shorter than the distance L2 exists to some extent or more.

  The number of meshes of the metal mesh constituting the fuel electrode side current collector 144 is preferably 30 to 200 (more preferably 40 to 120), and the aperture ratio of the metal mesh is 25 to 70% (more preferably) Is preferably 30 to 50%, the diameter of each wire is preferably 50 to 500 μm (more preferably 60 to 250 μm), and the width of the flat surfaces 212 and 222 is 10 μm to 300 μm (more preferably) Is preferably 50 .mu.m to 240 .mu.m (note that it is more preferable that the pore diameter of the electrode contacting the fuel electrode side current collector 144 be three or more times from the viewpoint of the contactability).

A-4. Effects of the present embodiment:
As described above, each power generation unit 102 constituting the fuel cell stack 100 of the present embodiment includes the unit cell 110, the fuel electrode side current collector 144, and the spacer 149. A unit cell 110 includes an electrolyte layer 112, and an air electrode 114 and a fuel electrode 116 facing each other in the vertical direction with the electrolyte layer 112 interposed therebetween. The fuel electrode side current collector 144 is disposed on the lower side with respect to the unit cell 110, and has a configuration in which a metal wire is knitted in a mesh shape. Further, the fuel electrode side current collector 144 has a plurality of cell facing portions 145 facing the single cells 110, a base 146 disposed on the lower side with respect to each cell facing portion 145, a base 146 and each cell facing portion And a connecting portion 147 connecting the two. The spacer 149 faces the lower surface of each cell facing portion 145. The cell facing portion 145 of the fuel electrode side current collector 144 has flat surfaces 212 and 222 in contact with the surface of the unit cell 110. In the vertical direction, a distance L1 from the spacer 149 to the surface (upper surface) facing the unit cell 110 in the cell facing portion 145 is shorter than the distance L2 from the spacer 149 to the unit cell 110. Since the power generation unit 102 of this embodiment has such a configuration, as described below, improvement of the electrical connectivity between the fuel electrode side current collector 144 and the unit cell 110, and the fuel electrode side collector The improvement of the gas diffusivity in the vicinity of the boundary between the current collector 144 and the unit cell 110 can be made compatible, and the performance of the power generation unit 102 can be improved.

  FIG. 11 is an explanatory view showing a configuration of a fuel electrode side current collector 144X in the first comparative example. In the fuel electrode side current collector 144X of the first comparative example, the distance L1 from the spacer 149 to the upper surface of the cell facing portion 145X in the vertical direction is the distance from the spacer 149 as in the above embodiment (see FIG. 8). There is a place (third position P3 in FIG. 11) shorter than the distance L2 to the single cell 110. Therefore, a space SP exists between the cell facing portion 145X and the single cell 110. However, in the fuel electrode side current collector 144X of the first comparative example, unlike the above embodiment, in the cell facing portion 145X, a flat surface is formed on the upper side (side facing the single cell 110) in each horizontal wire 210. And no flat surface is formed on the upper side of each longitudinal wire 220. Therefore, in the fuel electrode side current collector 144X of the first comparative example, both the contact points 216 of the respective horizontal wires 210 with the unit cell 110 and the contact points 226 of the vertical wires 220 with the unit cell 110 are both It is linear. As described above, in the first comparative example, the cell facing portion 145X of the fuel electrode side current collector 144X is in line contact with the unit cell 110 (fuel electrode 116). Therefore, in the first comparative example, the electrical connectivity between the fuel electrode side current collector 144X and the unit cell 110 can not be improved.

  FIG. 12 is an explanatory view showing a configuration of a fuel electrode side current collector 144Y in the second comparative example. In the fuel electrode side current collector 144Y of the second comparative example, as in the above embodiment (see FIG. 8), in the cell facing portion 145Y, the upper side (the side facing the single cell 110) in a portion of each horizontal wire 210 A flat surface 212 is formed on the surface of the vertical wire 220, and a flat surface 222 is also formed on the upper side of a portion of each longitudinal wire 220. These flat surfaces 212 and 222 are in contact with the surface of the unit cell 110 (fuel electrode 116). However, in the fuel electrode side current collector 144Y of the second comparative example, unlike the above embodiment, the flat surface 212 formed on the horizontal wire 210 and the flat surface 222 formed on the vertical wire 220 are continuous with each other. As a result, there is no location where the distance L1 from the spacer 149 to the upper surface of the cell facing portion 145 is shorter than the distance L2 from the spacer 149 to the single cell 110 in the vertical direction. Therefore, in the fuel electrode side current collector 144Y of the second comparative example, there is no space SP between the cell facing portion 145Y and the unit cell 110. Therefore, in the second comparative example, the gas diffusivity in the vicinity of the boundary between the fuel electrode side current collector 144Y and the unit cell 110 can not be improved.

  On the other hand, as described above, in the fuel electrode side current collector 144 of the present embodiment, the cell facing portion 145 has the flat surfaces 212 and 222 in contact with the surface of the unit cell 110, and In the direction, there is a place where the distance L1 from the spacer 149 to the upper surface of the cell facing portion 145 is shorter than the distance L2 from the spacer 149 to the unit cell 110. Therefore, in the power generation unit 102 of the present embodiment, the contact area between the cell facing portion 145 of the fuel electrode side current collector 144 and the unit cell 110 becomes large, and the cell facing portion 145 of the fuel electrode side current collector 144 A space SP is formed between the cell 110 and the cell 110. Therefore, according to the power generation unit 102 of the present embodiment, the electrical connectivity between the fuel electrode side current collector 144 and the single cell 110 can be improved, and the fuel electrode side current collector 144 and the single cell can be improved. Gas diffusivity near the boundary between 110 and 110 can be improved, and as a result, the performance of the power generation unit 102 can be improved.

  Further, as described above, in the fuel electrode side current collector 144 of the present embodiment, the minimum diameter R1 of the horizontal wire 210 at the position of the flat surface 212 is the maximum diameter R0 of the horizontal wire 210 at a position other than the flat surface 212. Similarly for the longitudinal wire 220, the minimum diameter of the longitudinal wire 220 at the position of the flat surface 222 is 1⁄2 or more of the maximum diameter of the longitudinal wire 220 at a position other than the flat surface 222. It has become. That is, the horizontal wires 210 and the vertical wires 220 are not excessively crushed at the places where the flat surfaces 212 and 222 are formed. Therefore, according to the power generation unit 102 of the present embodiment, the space SP for gas diffusion can be effectively secured near the boundary between the fuel electrode side current collector 144 and the unit cell 110, and the fuel electrode Gas diffusivity in the vicinity of the boundary between the side current collector 144 and the unit cell 110 can be effectively improved.

  Further, as described above, in the fuel electrode side current collector 144 of the present embodiment, in the vertical direction, in the direction (Y axis direction) orthogonal to the extending direction (X axis direction) of the horizontal wire 210, the horizontal wire 210 The width W1 of the flat surface 212 in this case is equal to or less than the width W2 at a position other than the flat surface 212 of the horizontal wire 210, and the vertical wire 220 extends in the vertical direction (Y-axis direction) The width of the flat surface 222 of the longitudinal wire 220 is equal to or less than the width at a position other than the flat surface 222 of the longitudinal wire 220 in the direction (X-axis direction) orthogonal to That is, the horizontal wires 210 and the vertical wires 220 are not excessively crushed at the places where the flat surfaces 212 and 222 are formed. Therefore, according to the power generation unit 102 of the present embodiment, the space SP for gas diffusion can be effectively secured near the boundary between the fuel electrode side current collector 144 and the unit cell 110, and the fuel electrode Gas diffusivity in the vicinity of the boundary between the side current collector 144 and the unit cell 110 can be effectively improved.

  Further, as described above, in the fuel electrode side current collector 144 of the present embodiment, the width W3 of the flat surface 212 of the horizontal wire 210 in the extending direction (X-axis direction) of the horizontal wire 210 in the vertical direction is The longitudinal wire 220 is larger than the width W4 at a position other than the flat surface 222 of the longitudinal wire 220, and the longitudinal wire 220 is also the longitudinal wire in the extension direction (Y-axis direction) of the longitudinal wire 220 in the vertical direction. The width of the flat surface 222 at 220 is greater than the width at locations other than the flat surface 212 of the transverse wire 210 intersecting the longitudinal wire 220. That is, the horizontal wire 210 and the vertical wire 220 are crushed to a certain extent or more at the places where the flat surfaces 212 and 222 are formed. Therefore, according to the power generation unit 102 of the present embodiment, the size of the flat surfaces 212 and 222 can be made constant or more, and the contact area between the cell facing portion 145 of the fuel electrode side current collector 144 and the unit cell 110 Can be effectively enlarged, and as a result, the electrical connectivity between the fuel electrode side current collector 144 and the unit cell 110 can be effectively improved.

  Further, as described above, in the fuel electrode side current collector 144 of the present embodiment, in a cross section (XZ cross section) parallel to both the extension direction of the horizontal wire 210 and the vertical direction, a direction (X Width W6 of the specific area satisfying the condition that the distance L1 is shorter than the distance L2 with respect to the width W5 of the area sandwiched by the respective center positions of the two flat surfaces 212 and 222 adjacent to each other in the axial direction). In the cross section (YZ cross section) parallel to both the extension direction of the longitudinal wire 220 and the vertical direction, the ratio of the vertical axis and the vertical wire 220 is similarly adjacent to each other in the direction (Y axis direction) perpendicular to the vertical direction. A specific region satisfying the condition that the distance L1 is shorter than the distance L2 in the region with respect to the width of the region sandwiched by the respective center positions of the two flat surfaces 212 and 222 that are fitted The proportion of the width is 0.8 or more. That is, for the horizontal wire 210 and the vertical wire 220, a specific region satisfying the condition that the distance L1 is shorter than the distance L2 exists to some extent or more. Therefore, according to the power generation unit 102 of the present embodiment, the space SP for gas diffusion can be effectively secured near the boundary between the fuel electrode side current collector 144 and the unit cell 110, and the fuel electrode Gas diffusivity in the vicinity of the boundary between the side current collector 144 and the unit cell 110 can be effectively improved.

  Further, as described above, in the fuel electrode side current collector 144 of the present embodiment, the cell facing portion 145 does not have a flat surface on the side facing the spacer 149. Therefore, according to the power generation unit 102 of the present embodiment, the space SP for gas diffusion can be more effectively secured near the boundary between the fuel electrode side current collector 144 and the unit cell 110, and the fuel Gas diffusivity in the vicinity of the boundary between the electrode-side current collector 144 and the unit cell 110 can be further effectively improved. Since the electrical connectivity between the fuel electrode side current collector 144 and the spacer 149 is not required, even if the cell facing portion 145 does not have a flat surface on the side facing the spacer 149, the power generation unit There is no impact on the performance of 102.

  Further, as described above, in the fuel electrode side current collector 144 of the present embodiment, from the unit cell 110 to the surface (lower surface) facing the spacer 149 in the cell facing portion 145 in the vertical direction (Z axis direction) There is a portion where the distance L3 of the distance L3 is shorter than the distance L2 from the spacer 149 to the single cell 110. Therefore, according to the power generation unit 102 of the present embodiment, since the space SP is formed between the cell facing portion 145 and the spacer 149, the gas in the vicinity of the boundary between the fuel electrode side current collector 144 and the spacer 149 The diffusivity can be improved, and as a result, the performance of the power generation unit 102 can be improved.

B. Modification:
The technology disclosed in the present specification is not limited to the above-described embodiment, and can be modified into various forms without departing from the scope of the present invention. For example, the following modifications are also possible.

  The configuration of the unit cell 110, the power generation unit 102, or the fuel cell stack 100 in the above embodiment is merely an example, and various modifications are possible. For example, in the above embodiment, each cell facing portion 145 constituting the fuel electrode side current collector 144 is disposed to face the base 146 in the vertical direction, but each cell facing portion 145 is not necessarily in the vertical direction. It does not have to be arranged to face the base 146 at Further, in the above embodiment, the spacers 149 are disposed between the cell facing portions 145 and the base portion 146 that constitute the fuel electrode side current collector 144, but the spacers 149 are the surfaces of the cell facing portions 145. It is not necessary to be disposed between each cell facing portion 145 and the base 146 as long as it faces the

  Further, the configuration of the cell facing portion 145 in the above embodiment is merely an example, and can be variously modified. For example, in the above embodiment, in the cell facing portion 145 constituting the fuel electrode side current collector 144, the upper and lower sides of the respective horizontal wires 210 are alternately arranged one by one along the extending direction of the respective horizontal wires 210. Wires 220 are arranged, and one horizontal wire 210 is alternately arranged on the upper side and the lower side of each longitudinal wire 220 along the extension direction of each longitudinal wire 220, but the extension of each lateral wire 210 A plurality of longitudinal wires 220 are alternately arranged on the upper and lower sides of each transverse wire 210 along the direction, and / or the upper and lower sides of each longitudinal wire 220 along the extension direction of each longitudinal wire 220. A plurality of lateral wires 210 may be alternately arranged on the side. FIG. 13 is an explanatory view showing a configuration of a fuel electrode side current collector 144a in a modification. In the cell facing portion 145a constituting the fuel electrode side current collector 144a of the modified example shown in FIG. 13, along the extending direction of each horizontal wire 210, two by two alternately on the upper side and lower side of each horizontal wire 210 Wires 220 are disposed, and two transverse wires 210 are disposed alternately on the upper and lower sides of each longitudinal wire 220 along the extension direction of each longitudinal wire 220. Also in the modification shown in FIG. 13, the cell facing portion 145 has flat surfaces 212 and 222 in contact with the surface of the single cell 110 as in the above embodiment, and the cell facing portion from the spacer 149 in the vertical direction If a distance L 1 to the upper surface of 145 is shorter than the distance L 2 from spacer 149 to unit cell 110, the electrical connectivity between fuel electrode side current collector 144 and unit cell 110 is achieved. As a result, the gas diffusibility in the vicinity of the boundary between the fuel electrode side current collector 144 and the unit cell 110 can be improved, and as a result, the performance of the power generation unit 102 can be improved. .

  Further, in the above embodiment, in the cell facing portion 145 of the fuel electrode side current collector 144, the entire flat surfaces 212 and 222 formed on the wires 210 and 220 contact the single cell 110, but the flat surface 212 , 222 may be in contact with the single cell 110.

  Further, in the above embodiment, in the cell facing portion 145 of the fuel electrode side current collector 144, no flat surface is formed on the lower side (side facing the spacer 149) in each horizontal wire 210, and Although the flat surface is not formed on the lower side of the longitudinal wires 220, the flat surface may be formed on the lower side of each transverse wire 210 and / or the lower side of each longitudinal wire 220.

  In the above embodiment, the distance L3 from the spacer 149 to the unit cell 110 is the distance L3 from the unit cell 110 to the surface (lower surface) facing the spacer 149 in the cell facing portion 145 in the vertical direction (Z axis direction). Although it is assumed that there is a portion shorter than the distance L2, there may be no portion where the distance L3 is shorter than the distance L2. If there is a place where the distance L3 is shorter than the distance L2, the cell is formed regardless of whether a flat surface is formed on the lower side (the side facing the spacer 149) in each horizontal wire 210 and each vertical wire 220. The space SP can be secured between the facing portion 145 and the spacer 149, and the gas diffusivity in the vicinity of the boundary between the fuel electrode side current collector 144 and the spacer 149 can be improved. As a result, power generation The performance of unit 102 can be improved.

  In the above embodiment, the minimum diameter of the wire at the flat surface position is at least half the maximum diameter of the wire at the positions other than the flat surface for both the horizontal wire 210 and the vertical wire 220. Such a configuration may be applied to only one of the lateral wire 210 and the longitudinal wire 220. Further, in the above embodiment, the width of the flat surface of the wire is the width other than the flat surface of the wire in the direction perpendicular to the extending direction of the wire in the vertical direction, for both the horizontal wire 210 and the vertical wire 220. Although the width is smaller than the width at the position, such a configuration may be applied to only one of the horizontal wire 210 and the vertical wire 220. Further, in the above embodiment, the width of the flat surface of the wire is the flat surface of the other wire intersecting with the wire in the wire extension direction in the vertical direction for both the horizontal wire 210 and the vertical wire 220 Although the width is assumed to be larger than in the other positions, such a configuration may be applied to only one of the horizontal wire 210 and the vertical wire 220. In the above embodiment, both of the horizontal wire 210 and the vertical wire 220 have two flat surfaces adjacent to each other in the direction orthogonal to the vertical direction in a cross section parallel to both the wire extending direction and the vertical direction. The ratio of the width of the specific area satisfying the condition that the distance L1 is shorter than the distance L2 in the area to the width of the area sandwiched by the respective center positions is 0.8 or more. Such a configuration may be applied to only one of the longitudinal wires 220. In the above embodiment, although both the horizontal wire 210 and the vertical wire 220 have flat surfaces, such a configuration may be applied to only one of the horizontal wire 210 and the vertical wire 220.

  Moreover, in the said embodiment, although the single cell 110 is provided with the intermediate | middle layer 180, the single cell 110 does not necessarily need to be provided with the intermediate | middle layer 180. FIG. Moreover, in the said embodiment, although the interconnector 150 and the air electrode side collector 134 (collector element 135) are integral members, the interconnector 150 and the air electrode side collector 134 are separate members. May be In the above embodiment, the air electrode side current collector 134 (the current collector element 135) is covered by the coat 136, but the air electrode side current collector 134 may not be covered by the coat 136. Further, in the above embodiment, the air electrode side current collector 134 (the current collector element 135) is in contact with the air electrode 114 via the bonding layer 138, but the air electrode side current collector 134 is via the bonding layer 138. Alternatively, it may be in contact with the air electrode 114.

  In the above embodiment, the number of unit cells 110 (power generation units 102) included in the fuel cell stack 100 is merely an example, and the number of unit cells 110 (power generation units 102) is required of the fuel cell stack 100. It can be appropriately determined according to the output voltage and the like. Moreover, the material which comprises each member in the said embodiment is an illustration to the last, and each member may be comprised with another material.

  Further, the method of manufacturing the fuel electrode side current collector 144 or the like in the above embodiment is merely an example, and various modifications are possible.

  In addition, the configuration of the fuel electrode side current collector 144 in the above embodiment (the flat surface 212 and 222 where the cell facing portion 145 contacts the surface of the single cell 110 and the cell facing portion 145 from the spacer 149 in the vertical direction The configuration in which the distance L1 to the upper surface of L is shorter than the distance L2 from the spacer 149 to the unit cell 110) is not necessarily adopted in all of the plurality of power generation units 102 constituting the fuel cell stack 100. Instead, it may be employed in at least one of the plurality of power generation units 102 constituting the fuel cell stack 100.

  In the above embodiment, as the configuration of the fuel electrode side current collector 144, the cell facing portion 145 has flat surfaces 212 and 222 in contact with the surface of the single cell 110, and the cell 149 faces the cell in the vertical direction. Although the configuration has been described in which there is a portion where the distance L1 to the upper surface of the portion 145 is shorter than the distance L2 from the spacer 149 to the unit cell 110, instead of the fuel electrode side current collector 144, or The configuration of the air electrode side current collector 134 may be the same as that of the body 144.

  Further, in the above embodiment, SOFCs that generate electric power using electrochemical reaction between hydrogen contained in fuel gas and oxygen contained in oxidant gas are targeted, but the present invention relates to the electrolysis reaction of water The present invention is similarly applicable to an electrolysis cell unit that is a constituent unit of a solid oxide electrolytic cell (SOEC) that uses hydrogen to generate hydrogen, and an electrolysis cell stack provided with a plurality of electrolysis cell units. The configuration of the electrolytic cell stack is not described in detail here because it is known as described in, for example, JP-A-2016-81813, but it is roughly the same as the fuel cell stack 100 in the embodiment described above. Configuration. That is, the fuel cell stack 100 in the embodiment described above may be read as an electrolysis cell stack, the power generation unit 102 may be read as an electrolysis cell unit, and the single cell 110 may be read as an electrolysis single cell. However, during operation of the electrolytic cell stack, a voltage is applied between the two electrodes so that the air electrode 114 is positive (anode) and the fuel electrode 116 is negative (cathode), and through the communication hole 108 Water vapor as a source gas is supplied. As a result, an electrolysis reaction of water occurs in each electrolysis cell unit, hydrogen gas is generated in the fuel chamber 176, and hydrogen is taken out to the outside of the electrolysis cell stack through the communication hole 108. Also in the electrolytic cell unit and the electrolytic cell stack of such a configuration, if the configuration similar to that of the above embodiment is adopted, the electrical connectivity between the current collector and the electrolytic single cell can be improved, Gas diffusivity in the vicinity of the boundary between the current collector and the single electrolytic cell can be improved, and as a result, the performance of the electrolytic cell unit can be improved.

 In the above embodiment, the solid oxide fuel cell (SOFC) has been described as an example, but the present invention is also applicable to other types of fuel cells (or electrolytic cells) such as a molten carbonate fuel cell (MCFC). It is applicable.

22: Bolt 24: Nut 26: Insulating sheet 27: Gas passage member 28: Body portion 29: Branching portion 100: Fuel cell stack 102: Fuel cell power generation unit 104: End plate 106: End plate 108: Communication hole 110: Single cell 112: electrolyte layer 114: air electrode 116: fuel electrode 120: separator 121: hole 124: joint 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 135: Current collector element 136: Coat 138: Bonding layer 140: Fuel electrode side frame 141: Hole 142: Fuel gas supply communication hole 143: Fuel gas discharge communication hole 144: Fuel electrode side current collector 145 : Cell facing part 146: Base 147: Joint part 149: Spacer 15 0: Interconnector 161: Oxidizer gas introduction manifold 162: Oxidizer gas discharge manifold 166: Air chamber 171: Fuel gas inlet manifold 172: Fuel gas discharge manifold 176: Fuel chamber 180: Middle layer 210: Transverse wire 212: Flat surface 214: Contact point 216: Contact point 220: Longitudinal wire 222: Flat surface 224: Contact point 226: Contact point

Claims (9)

A single cell including an electrolyte layer, and an air electrode and a fuel electrode facing each other in a first direction across the electrolyte layer;
A current collector disposed on one side in the first direction with respect to the unit cell, the plurality of cell facing portions facing the unit cell, and the first with respect to each cell facing portion A current collector including a base disposed on the one side in a direction, and a connecting part connecting the base and the cell facing parts;
A spacer facing the surface on the one side in the first direction of each of the cell facing portions;
In the electrochemical reaction unit comprising
The current collector has a configuration in which a metal wire is knitted in a mesh shape,
The cell facing portion has a flat surface at least a portion of which contacts the surface of the single cell,
In the first direction, there is a portion where a distance L1 from the spacer to the surface of the cell facing portion facing the single cell is shorter than a distance L2 from the spacer to the single cell. Electrochemical reaction unit. In the electrochemical reaction unit according to claim 1,
An electrochemical reaction unit, wherein the minimum diameter of the wire at the position of the flat surface is 1/2 or more of the maximum diameter of the wire at a position other than the flat surface. In the electrochemical reaction unit according to claim 1 or 2,
The width W1 of the flat surface of the one wire is less than or equal to the width W2 at a position other than the flat surface of the one wire in a direction orthogonal to the extending direction of the one wire in the first direction view. An electrochemical reaction unit characterized in that The electrochemical reaction unit according to any one of claims 1 to 3
In the first direction, in the extending direction of the one wire, a width W3 of the flat surface of the one wire is a width at a position other than the flat surface of the other wire intersecting the one wire An electrochemical reaction unit characterized by being larger than W4. The electrochemical reaction unit according to any one of claims 1 to 4
In a cross section parallel to both the extending direction of one of the wires and the first direction, the center position of two flat surfaces adjacent to each other in a second direction orthogonal to the first direction An electrochemical reaction unit characterized in that the ratio of the specific region width W6 satisfying the condition that the distance L1 is shorter than the distance L2 in the region to the width W5 of the separated region is 0.8 or more. In the electrochemical reaction unit according to any one of claims 1 to 5,
The electrochemical reaction unit, wherein the cell facing portion does not have a flat surface on the side facing the spacer. In the electrochemical reaction unit according to any one of claims 1 to 6,
In the first direction, a distance L3 from the unit cell to the surface of the cell facing portion facing the spacer is shorter than the distance L2 from the spacer to the unit cell. Electrochemical reaction unit. In the electrochemical reaction unit according to any one of claims 1 to 7,
The electrochemical reaction unit, wherein the unit cell is a fuel cell unit cell. In an electrochemical reaction cell stack comprising a plurality of electrochemical reaction units arranged in the first direction,
An electrochemical reaction cell stack, wherein at least one of the plurality of electrochemical reaction units is the electrochemical reaction unit according to any one of claims 1 to 8.

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