JP2017224525A - Collector member-electrochemical reaction single cell composite body, and electrochemical reaction cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit cracks of an electrochemical reaction single cell from occurring.SOLUTION: A collector member-electrochemical reaction single composite body comprises: an electrochemical reaction single cell including an air electrode and a fuel electrode opposite to each other in a first direction by sandwiching an electrolyte layer and an electrolyte layer; and a collector member which is disposed on a specific electrode side of the single cell and has a plurality of protrusions in contact with the surface of the specific electrode. The specific electrode has a first portion which is at least one portion of a protrusion overlap area where overlap with the protrusion is made in a first direction view. In a second direction orthogonal to the first direction, the first portion is located next to the first portion and has lower porosity than the second portion where overlap with the protrusion is not made in the first direction view.SELECTED DRAWING: Figure 6

Description

  The technology disclosed by the present specification relates to a current collecting member-electrochemical reaction single cell composite.

  One type of fuel cell that generates electricity using an electrochemical reaction between hydrogen and oxygen is a solid oxide fuel cell (hereinafter referred to as “SOFC”) having an electrolyte layer containing a solid oxide. It has been. A fuel cell single cell (hereinafter simply referred to as “single cell”) that is a constituent unit of SOFC includes an electrolyte layer, and an air electrode and a fuel electrode that face each other in a predetermined direction with the electrolyte layer interposed therebetween.

  The SOFC is provided with a current collecting member that collects electric energy obtained by a power generation reaction in a single cell. The current collecting member is configured to have a plurality of convex portions that are in contact with the surface of the electrode in order to exhibit the current collecting function without hindering the supply of the reaction gas into the electrode (see, for example, Patent Document 1). . In the present specification, a structure including a single cell and a current collecting member is referred to as a current collecting member-fuel cell single cell complex.

JP 2014-216297 A

  In the conventional current collecting member-fuel cell single cell complex, since the plurality of convex portions of the current collecting member are in contact with the surface of the electrode, the load from the current collecting member is in contact with the plurality of convex portions of the electrode. There is a risk that the single cell will break.

 Such a problem is caused by the fact that an electrolytic single cell and a current collecting member are constituent units of a solid oxide electrolytic cell (hereinafter referred to as “SOEC”) that generates hydrogen using an electrolysis reaction of water. This is also a problem common to the current collecting member-electrolytic single cell composite composed of: In the present specification, the current collecting member-fuel cell single cell composite and the current collecting member-electrolytic single cell composite are collectively referred to as a current collecting member-electrochemical reaction single cell composite. Such a problem is not limited to SOFC and SOEC, but is also a problem common to current collector-electrochemical reaction single cell composites composed of other types of electrochemical reaction single cells and current collection members. is there.

  In this specification, the technique which can solve the subject mentioned above is disclosed.

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

(1) A current collecting member-electrochemical reaction single cell complex disclosed in this specification includes an electrolyte layer and an air electrode and a fuel electrode facing each other in a first direction with the electrolyte layer interposed therebetween. A current collecting member having a plurality of protrusions disposed on a specific electrode side that is at least one of the air electrode and the fuel electrode of the reaction single cell, and the electrochemical reaction single cell; and In the current collecting member-electrochemical reaction single cell complex comprising: the specific electrode is a first part that is at least a part of a convex overlapping region that overlaps the convex part when viewed in the first direction, A first lower porosity than a second portion that is located next to the first portion in a second direction orthogonal to the first direction and that does not overlap the convex portion when viewed in the first direction. It has a part. According to the current collecting member-electrochemical reaction single cell complex, the porosity of the first portion which is at least a part of the convex overlapping region where the load from the current collecting member acts intensively in the specific electrode is low. Therefore, the strength of the first portion can be increased, and the occurrence of cracking of the electrochemical reaction single cell due to the load concentration from the current collecting member can be suppressed. In the specific electrode, since the porosity of the second portion that does not overlap with the convex portion in the first direction is high, it is possible to suppress a decrease in the diffusibility of the reaction gas in the specific electrode.

(2) In the current collecting member-electrochemical reaction single cell complex, the specific electrode includes a conductive metal, and the content (vol%) of the conductive metal in the first portion is the second value. It is good also as a structure higher than the content rate (vol%) of the said conductive metal of the part. According to the current collecting member-electrochemical reaction single cell complex, in the specific electrode, the content of the conductive metal in the first portion located in the main conduction path between the current collecting member and the current collecting member can be increased. The conductivity of the electrochemical reaction single cell can be improved.

(3) In the current collecting member-electrochemical reaction single cell complex, the specific electrode includes oxide ion conductive ceramic particles, and the content of the oxide ion conductive ceramic particles in the first portion ( (vol%) may be higher than the content (vol%) of the oxide ion conductive ceramic particles in the second portion. According to the current collecting member-electrochemical reaction single cell composite, the strength of the first portion, which is the portion where the load from the current collecting member acts intensively, can be effectively improved in the specific electrode. The occurrence of cracks in the electrochemical reaction single cell can be effectively suppressed.

(4) In the current collecting member-electrochemical reaction single cell complex, the first portion is the entire portion from the surface on the electrolyte layer side to the surface on the current collecting member side in the convex portion overlapping region. It is good also as a certain structure. According to the current collecting member-electrochemical reaction single cell composite, the first portion having a low porosity in all portions from the surface on the electrolyte layer side to the surface on the current collecting member side in the convex overlapping region of the specific electrode Therefore, the occurrence of cracking of the electrochemical reaction single cell can be effectively suppressed.

(5) In the current collecting member-electrochemical reaction single cell complex, in the first direction, the region occupied by the first portion in the convex overlapping region with respect to the thickness of the convex overlapping region. The thickness ratio may be 50% or less. According to the current collecting member-electrochemical reaction single cell composite, it is possible to prevent the electrochemical reaction single cell from cracking while suppressing a decrease in gas diffusivity by keeping the porosity of the specific electrode as a whole high to some extent. Can be suppressed.

(6) In the current collecting member-electrochemical reaction single cell complex, the specific electrode may have a plurality of the first portions. According to the current collecting member-electrochemical reaction single cell complex, by providing a plurality of high-strength first portions while suppressing a decrease in gas diffusibility as a whole of the specific electrode, Generation of cracks can be effectively suppressed.

(7) In the current collecting member-electrochemical reaction single cell complex, the specific electrode may include a plurality of the first portions that overlap each of the plurality of convex portions when viewed in the first direction. Good. According to the current collecting member-electrochemical reaction single cell complex, a plurality of first portions having high strength are arranged in a direction orthogonal to the first direction while suppressing a decrease in gas diffusibility as a whole of the specific electrode. By providing, generation | occurrence | production of the crack of an electrochemical reaction single cell can be suppressed more effectively.

  The technology disclosed in the present specification can be realized in various forms, for example, a current collecting member-electrochemical reaction single cell composite (a current collecting member-fuel cell single cell composite or a current collector). Electric member-electrolytic single cell composite), current collecting member-electrochemical reaction unit (fuel cell power generation unit or electrolytic cell unit) comprising an electrochemical reaction single cell composite, a plurality of current collecting members-electrochemical reaction single cell or It can be realized in the form of an electrochemical reaction cell stack (fuel cell stack or electrolytic cell stack) including an electrochemical reaction unit, a manufacturing method thereof, and the like.

1 is a perspective view showing an external configuration of a fuel cell stack 100 in a first 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. FIG. 3 is an explanatory diagram showing a YZ cross-sectional configuration of a fuel cell stack 100 at a position of III-III in FIG. It is explanatory drawing which shows XZ cross-section structure of the two electric power generation units 102 adjacent to each other in the same position as the cross section shown in FIG. It is explanatory drawing which shows the YZ cross-section structure of the two electric power generation units 102 adjacent to each other in the same position as the cross section shown in FIG. 4 is an explanatory diagram showing a detailed configuration of a fuel electrode 116. FIG. 4 is an explanatory diagram showing the porosity at each position of the fuel electrode 116. FIG. It is explanatory drawing which shows the detailed structure of the fuel electrode 116a in 2nd Embodiment. It is explanatory drawing which shows the specific method of thickness Tx of 1st part PA1 in 2nd Embodiment. It is explanatory drawing which shows the detailed structure of the fuel electrode 116b in 3rd Embodiment. It is explanatory drawing which shows the detailed structure of the fuel electrode 116c in 4th Embodiment. It is explanatory drawing which shows the structure of the Example about the current collection member-single cell composite_body | complex 107 of each embodiment. It is explanatory drawing which shows the detailed structure of the fuel electrode 116 in a modification. It is explanatory drawing which shows the specific method of thickness Tx of 1st part PA1 in a modification.

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

  The fuel cell stack 100 includes a plurality (seven in this embodiment) of 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 side by side in a predetermined arrangement direction (vertical direction in the present embodiment). The pair of end plates 104 and 106 are arranged so as to sandwich an 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 penetrating in the vertical direction are formed in the peripheral portion around the Z direction of each layer (power generation unit 102, end plates 104, 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 to form a communication hole 108 extending in the vertical direction from one end plate 104 to the other end plate 106. In the following description, the holes formed in each layer of the fuel cell stack 100 to form the communication holes 108 may also be referred to as communication holes 108.

  Bolts 22 extending in the vertical direction are inserted into the communication holes 108, and the fuel cell stack 100 is fastened by the bolts 22 and nuts 24 fitted on both sides of the bolts 22. 2 and 3, between the nut 24 fitted on one side (upper side) of the bolt 22 and the upper surface of the end plate 104 constituting the upper end of the fuel cell stack 100, and the bolt An insulating sheet 26 is interposed between the nut 24 fitted on the other side (lower side) of 22 and the lower surface of the end plate 106 constituting the lower end of the fuel cell stack 100. However, in a place where a gas passage member 27 described later is provided, an insulating sheet disposed between the nut 24 and the surface of the end plate 106 on the upper and lower sides of the gas passage member 27 and the gas passage member 27, respectively. 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 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, the fuel cell stack 100 is located near the midpoint of one side (the X-axis positive direction side of two sides parallel to the Y-axis) on the outer periphery around the Z-direction. The space formed by the bolt 22 (bolt 22A) and the communication hole 108 through which the bolt 22A is inserted is introduced with the oxidant gas OG from the outside of the fuel cell stack 100, and the oxidant gas OG is generated by each power generation. It functions as an oxidant gas introduction manifold 161 that is a gas flow path to be supplied to the unit 102, and is the midpoint of the side opposite to the side (X-axis negative direction side of two sides parallel to the Y-axis) The space formed by the bolts 22 (bolts 22B) located in the vicinity and the communication holes 108 through which the bolts 22B are inserted contains the oxidant off-gas OOG that is the gas discharged from the air chamber 166 of each power generation unit 102. Burning 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 midpoint of one side (the side on the Y axis positive direction side of two sides parallel to the X axis) on the outer periphery of the fuel cell stack 100 around the Z direction The space formed by the bolt 22 (bolt 22D) positioned at the position and the communication hole 108 through which the bolt 22D is inserted is introduced with the fuel gas FG from the outside of the fuel cell stack 100, and the fuel gas FG is generated by each power generation. Bolt 22 that functions as a fuel gas introduction manifold 171 to be supplied to the unit 102 and is located in the vicinity of the midpoint of the opposite side (the side on the Y axis negative direction side of the two sides parallel to the X axis). The space formed by the (bolt 22E) and the communication hole 108 through which the bolt 22E is inserted is a fuel cell stack 1 that uses the fuel off-gas FOG that 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, as the fuel gas FG, for example, hydrogen-rich gas obtained by reforming city gas is used.

  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 part 29 communicates with the hole of the main body part 28. A gas pipe (not shown) is connected to the branch portion 29 of each gas passage member 27. Further, as shown in FIG. 2, the hole of the main body portion 28 of the gas passage member 27 disposed at the position of the bolt 22 </ b> A forming the oxidant gas introduction manifold 161 communicates with the oxidant gas introduction manifold 161. The hole of the main body portion 28 of the gas passage member 27 disposed at the position of the bolt 22 </ b> B that forms the oxidant gas discharge manifold 162 communicates with the oxidant gas discharge manifold 162. Further, as shown in FIG. 3, the hole of the main body portion 28 of the gas passage member 27 arranged at the position of the bolt 22D forming the fuel gas introduction manifold 171 communicates with the fuel gas introduction manifold 171 and the fuel gas The hole of the main body portion 28 of the gas passage member 27 disposed at the position of the bolt 22 </ b> E forming the discharge manifold 172 communicates with the fuel gas discharge manifold 172.

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

(Configuration of power generation unit 102)
4 is an explanatory diagram showing an XZ cross-sectional configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. 2, and FIG. 5 is adjacent to each other at the same position as the cross section shown in FIG. It is explanatory drawing which shows the YZ cross-section structure of the two electric power generation units.

  As shown in FIGS. 4 and 5, the power generation unit 102 includes a single cell 110, a separator 120, an air electrode side frame 130, an air electrode side current collector 134, a fuel electrode side frame 140, and a fuel electrode side. A current collector 144 and a pair of interconnectors 150 constituting the uppermost layer and the lowermost layer of the power generation unit 102 are provided. The separator 120, the air electrode side frame 130, the fuel electrode side frame 140, and the periphery of the interconnector 150 around the Z direction are formed with holes corresponding to the communication holes 108 through which the bolts 22 are inserted.

  The interconnector 150 is a substantially rectangular flat plate-shaped conductive member larger than the single cell 110 as viewed in the Z direction, and is made of, for example, ferritic stainless steel. The interconnector 150 ensures electrical continuity between the power generation units 102 and prevents reaction gas from being mixed between the power generation units 102. In the present embodiment, when two power generation units 102 are arranged adjacent to each other, one interconnector 150 is shared by two adjacent power generation units 102. That is, the upper interconnector 150 in a power generation unit 102 is the same member as the lower interconnector 150 in another power generation unit 102 adjacent to the upper side of the power generation unit 102. Further, since the fuel cell stack 100 includes the pair of end plates 104 and 106, the power generation unit 102 located at the top in the fuel cell stack 100 does not include the upper interconnector 150 and is located at the bottom. The power generation unit 102 does not include the lower interconnector 150 (see FIGS. 2 and 3).

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

  The electrolyte layer 112 is a substantially rectangular flat plate-shaped member. For example, YSZ (yttria stabilized zirconia), ScSZ (scandia stabilized zirconia), SDC (samarium doped ceria), GDC (gadolinium doped ceria), perovskite oxide It is formed with solid oxides such as. The air electrode 114 is a substantially rectangular flat plate-shaped member, and is formed of, for example, a perovskite oxide (for example, LSCF (lanthanum strontium cobalt iron oxide), LSM (lanthanum strontium manganese oxide), LNF (lanthanum nickel iron)). Has been. The fuel electrode 116 is a substantially rectangular flat plate-like member, and is formed of, for example, Ni (nickel), cermet made of Ni and ceramic particles, Ni-based alloy, or the like. The fuel electrode 116 corresponds to a specific electrode in the claims. The configuration of the fuel electrode 116 will be described in detail later. Thus, the single cell 110 (power generation unit 102) of the present embodiment is a solid oxide fuel cell (SOFC) that uses a solid oxide as an electrolyte.

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

 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. The hole 131 of the air electrode side frame 130 forms an air chamber 166 that faces the air electrode 114. The air electrode side frame 130 is in contact with the peripheral edge portion of the surface of the separator 120 opposite to the side facing the electrolyte layer 112 and the peripheral edge portion of the surface of the interconnector 150 facing the air electrode 114. . The pair of interconnectors 150 included in the power generation unit 102 is electrically insulated by the air electrode side frame 130. The air electrode side frame 130 has an oxidant gas supply communication hole 132 communicating the oxidant gas introduction manifold 161 and the air chamber 166, and an oxidant gas communicating the air chamber 166 and the oxidant gas discharge manifold 162. A discharge communication hole 133 is formed.

  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 near the center, and is made of, for example, metal. The hole 141 of the fuel electrode side frame 140 forms a fuel chamber 176 that faces 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, the fuel electrode side frame 140 has a fuel gas supply communication hole 142 that connects the fuel gas introduction manifold 171 and the fuel chamber 176, and a fuel gas discharge communication hole 143 that connects the fuel chamber 176 and the fuel gas discharge manifold 172. And are formed.

  The fuel electrode side current collector 144 is disposed in the fuel chamber 176. The fuel electrode side current collector 144 includes an interconnector facing portion 146, an electrode facing portion 145, and a connecting portion 147 that connects the electrode facing portion 145 and the interconnector facing portion 146. For example, nickel or a nickel alloy It is made of stainless steel or the like. In the present embodiment, the fuel electrode side current collector 144 is formed of Ni foil. A conductive bonding layer 310 is disposed on substantially the entire surface of the electrode facing portion 145 facing the fuel electrode 116. In the present embodiment, the bonding layer 310 is made of NiO (nickel oxide). The bonding layer 310 disposed on the surface of the electrode facing portion 145 is a surface of the fuel electrode 116 opposite to the side facing the electrolyte layer 112 (that is, the side of the fuel electrode 116 facing the fuel electrode side current collector 144). Hereinafter, it is in contact with the current collecting member facing surface S1). The interconnector facing portion 146 is in contact with the 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 include the lower interconnector 150, the interconnector facing portion 146 in the power generation unit 102 has a lower end plate. 106 is in contact. Since the fuel electrode side current collector 144 and the bonding layer 310 have such a configuration, the fuel electrode 116 and the interconnector 150 (or the end plate 106) are electrically connected. Note that a spacer 149 made of, for example, mica is disposed between the electrode facing portion 145 and the interconnector facing portion 146. Therefore, the fuel electrode side current collector 144 follows the deformation of the power generation unit 102 due to the temperature cycle and the reaction gas pressure fluctuation, and the fuel electrode 116 and the interconnector 150 (or the end plate 106) via the fuel electrode side current collector 144. The electrical connection with is maintained well.

As shown in FIG. 4, in this embodiment, the fuel electrode side current collector 144 is manufactured by cutting a rectangular flat plate member and bending the plurality of rectangular portions. The bent rectangular portion becomes the electrode facing portion 145, the flat plate portion other than the bent raised portion becomes the interconnector facing portion 146, and the portion connecting the electrode facing portion 145 and the interconnector facing portion 146 is connected. Part 147. In addition, in the partial enlarged view shown in FIG. 4, in order to show the manufacturing method of the fuel electrode side collector 144, the state before the bending raising process of a part of several rectangular part is shown. In the present embodiment, the electrode facing portion 145 and the bonding layer 310 are arranged in a substantially lattice shape (on each intersection of the lattice) as viewed in the Z direction. As viewed in the Z direction, the area of each electrode facing portion 145 (that is, the area of the bonding layer 310) is, for example, 1 to 1000 (mm ² ).

  In this specification, in each power generation unit 102, an assembly of the bonding layer 310, the fuel electrode side current collector 144, and the interconnector 150 positioned on the fuel electrode 116 side of the single cell 110 is used as the fuel electrode side current collector. This is referred to as member 400. Since the fuel electrode side current collecting member 400 has the configuration as described above, a plurality of plate-shaped members (interconnectors 150) larger than the single cell 110 and the current collecting member facing surface S1 of the fuel electrode 116 are in contact with each other as viewed in the Z direction. Convex portion (an assembly of the electrode facing portion 145 of the fuel electrode side current collector 144 and the bonding layer 310 provided on the surface of the electrode facing portion 145, hereinafter referred to as “current collecting member convex portion 410”. ) (See FIG. 6). The fuel electrode side current collecting member 400 corresponds to the current collecting member in the claims, and the plurality of current collecting member convex portions 410 correspond to the plurality of convex portions in the claims. Further, in this specification, a structure including the single cell 110 and the fuel electrode side current collecting member 400 (the fuel electrode side current collector 144, the bonding layer 310, and the interconnector 150) is referred to as a current collecting member-fuel cell. This is referred to as a single cell composite (hereinafter simply referred to as “current collecting member-single cell composite”) 107.

  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 current collector elements 135 having a substantially quadrangular prism shape, and is formed of, for example, ferritic stainless steel. The air electrode side current collector 134 is in contact with the surface of the air electrode 114 opposite to the side facing the electrolyte layer 112 and the surface of the interconnector 150 facing the air electrode 114. However, as described above, since the power generation unit 102 located at the top in the fuel cell stack 100 does not include the upper interconnector 150, the air electrode side current collector 134 in the power generation unit 102 includes the upper end plate. 104 is in contact. Since the air electrode side current collector 134 has such a configuration, the air electrode 114 and the interconnector 150 (or the end plate 104) are electrically connected. In the present embodiment, the air electrode side current collector 134 and the interconnector 150 are formed as an integral member. That is, a flat plate portion perpendicular to the vertical direction (Z-axis direction) of the integrated member functions as the interconnector 150 and is formed so as to protrude from the flat plate portion toward the air electrode 114. The current collector element 135 that is a plurality of convex portions functions as the air electrode side current collector 134. Moreover, the integral member of the air electrode side current collector 134 and the interconnector 150 may be covered with a conductive coat, and between the air electrode 114 and the air electrode side current collector 134, A conductive bonding layer to be bonded may be interposed.

A-2. Operation of the 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 branch portion 29 of the gas passage member 27 and the hole of the main body portion 28, and the oxidant gas introduction manifold 161 oxidizes each power generation unit 102. It is supplied to the air chamber 166 through the agent gas supply communication hole 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 chamber 176 is supplied 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, oxygen contained in the oxidant gas OG and hydrogen contained in the fuel gas FG in the single cell 110. Power is generated by an electrochemical reaction. This power generation reaction is an exothermic reaction. In each power generation unit 102, the air electrode 114 of the single cell 110 is electrically connected to one interconnector 150 via the air electrode side current collector 134, and the fuel electrode 116 is connected via the fuel electrode side current collector 144. The other interconnector 150 is electrically connected. The plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. Therefore, electrical energy generated in each power generation unit 102 is taken out from the end plates 104 and 106 that function as output terminals of the fuel cell stack 100. Since SOFC generates power at a relatively high temperature (for example, 700 ° C. to 1000 ° C.), the fuel cell stack 100 is heated by a heater (after the startup until the high temperature can be maintained by heat generated by 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 via the oxidant gas discharge communication hole 133 as shown in FIGS. The fuel cell stack 100 is connected to the branch portion 29 via a gas pipe (not shown) 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 outside. 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 via the fuel gas discharge communication hole 143, and further to the fuel gas. The gas passage member 27 provided at the position of the discharge manifold 172 passes through the body portion 28 and the branch portion 29 and passes through a gas pipe (not shown) connected to the branch portion 29 to the outside of the fuel cell stack 100. Discharged.

A-3. Detailed configuration of the fuel electrode 116:
FIG. 6 is an explanatory diagram showing a detailed configuration of the fuel electrode 116. FIG. 6 shows an enlarged view of the configuration of the X1 portion of FIG. As shown in FIG. 6, the fuel electrode 116 includes a substrate layer 220 and an active layer 210. The substrate layer 220 is a portion on the side (lower side) close to the fuel electrode side current collector 144 in the Z direction, and includes the current collecting member facing surface S1. The active layer 210 is a portion located between the substrate layer 220 and the electrolyte layer 112 in the Z direction, and is a surface facing the electrolyte layer 112 in the fuel electrode 116 (hereinafter referred to as “electrolyte layer facing surface S2”). It is a part including.

  The substrate layer 220 of the fuel electrode 116 mainly supports the other layers (the active layer 210, the electrolyte layer 112, and the air electrode 114) constituting the single cell 110, and diffuses the fuel gas FG supplied from the fuel chamber 176. And a layer functioning as a field for collecting electricity obtained by the power generation reaction. The active layer 210 is a layer that functions mainly as a reaction field between oxide ions supplied from the electrolyte layer 112 and hydrogen contained in the fuel gas FG supplied from the fuel chamber 176 via the substrate layer 220. is there.

  In this embodiment, both the active layer 210 and the substrate layer 220 of the fuel electrode 116 are formed by cermet of Ni as a conductive metal and YSZ particles as an oxide ion conductive ceramic. In this embodiment, in order to increase the activity of the active layer 210, the Ni content (vol%) in the active layer 210 is higher than the Ni content in the substrate layer 220. In addition, in order to increase the strength of the substrate layer 220, the thickness of the substrate layer 220 is larger than the thickness of the active layer 210 in the Z direction. Further, the porosity (vol%) of the substrate layer 220 is higher than the porosity of the active layer 210 in order to increase the gas diffusibility of the substrate layer 220.

  In the present embodiment, a region of the substrate layer 220 having a thickness Tx from the interface BO with the active layer 210 (hereinafter referred to as “specific region SA”) is perpendicular to the Z direction (hereinafter referred to as “plane direction”). In other words, the porosity of the first portion PA1 is lower than the porosity of the second portion PA2. Here, the first portion PA1 faces the tip surface of the current collecting member convex portion 410 (the assembly of the electrode facing portion 145 and the bonding layer 310) (that is, the fuel electrode 116 of the bonding layer 310) as viewed in the Z direction. This is a portion included in the convex overlapping area AR1 that overlaps the surface on the side to be processed. Therefore, the first portion PA1 is a portion where the load from the fuel electrode side current collecting member 400 acts intensively and is a portion located in a main conduction path between the first electrode PA1 and the fuel electrode side current collecting member 400. It can be said. The second portion PA2 is a portion included in the convex non-overlapping region AR2 that does not overlap the tip surface of the current collecting member convex portion 410 when viewed in the Z direction. Thus, in the present embodiment, in the first portion PA1 that overlaps the tip surface of the current collecting member convex portion 410 when viewed in the Z direction in the specific area SA of the substrate layer 220, the current collecting member convex portion when viewed in the Z direction. The porosity is lower than that of the second portion PA2 that does not overlap the tip surface of 410.

  In the present embodiment, the content of the conductive metal (Ni) and oxide ion conductive ceramics (YSZ) particles in the first part PA1 is lower than that in the second part PA2. (Vol%) is high. In the present embodiment, the configuration of the region other than the specific region SA in the substrate layer 220 (porosity, conductive metal content, etc.) is substantially the same as the configuration of the second portion PA2. In the present embodiment, the substrate layer 220 includes a plurality of first portions PA1 and a plurality of second portions PA2, and each second portion PA2 includes two first portions PA1 in the plane direction. Located between.

  FIG. 7 is an explanatory diagram showing the porosity at each position of the fuel electrode 116. In the upper part of FIG. 7, a curve C (L1) indicating the porosity at each position on the virtual line L1 (see FIG. 6) that equally divides the protrusion overlapping area AR1 in the plane direction in the cross section of the fuel electrode 116 is shown. Has been. That is, the curve C (L1) indicates the porosity at each position of the convex overlap region AR1 of the fuel electrode 116. As shown in FIG. 6, points P <b> 11 to P <b> 14 in the upper part of FIG. In the lower part of FIG. 7, in the cross section of the fuel electrode 116, a curve C (L2) indicating the porosity at each position on the virtual line L2 (see FIG. 6) equally dividing the convex non-overlapping region AR2 in the surface direction. )It is shown. That is, the curve C (L2) indicates the porosity at each position of the convex non-overlapping region AR2 of the fuel electrode 116. As shown in FIG. 6, points P <b> 21 to P <b> 24 in the lower part of FIG. 7 are intersections between the virtual line L <b> 2 and the boundary of each part in the fuel electrode 116.

  As shown in the lower part of FIG. 7, in the non-overlapping region AR2 of the fuel electrode 116, the porosity is substantially constant in the entire substrate layer 220 including the second portion PA2. Also in the active layer 210, the porosity is substantially constant. As described above, the porosity of the active layer 210 is lower than the porosity of the substrate layer 220.

  On the other hand, as shown in the upper part of FIG. 7, in the convex part overlapping area AR1 in the fuel electrode 116, the porosity of the part other than the first part PA1 in the substrate layer 220 is the convex part non-overlapping area shown in the lower part of FIG. Although the porosity of the substrate layer 220 of AR2 is substantially the same, the porosity of the first portion PA1 in the substrate layer 220 is lower than the porosity of other portions in the substrate layer 220. That is, the porosity of the first portion PA1 in the substrate layer 220 is lower than the porosity of the second portion PA2. Note that the porosity of the active layer 210 is lower than the porosity of the substrate layer 220 as in the convex non-overlapping region AR2.

  In the present embodiment, the ratio of the thickness Tx of the region occupied by the first portion PA1 to the thickness To of the entire fuel electrode 116 (projection overlapping region AR1) is 50% or less. Therefore, the ratio of the first portion PA1 in the entire fuel electrode 116 is relatively small.

A-4. Manufacturing method of fuel cell stack 100:
A method of manufacturing the fuel cell stack 100 having the above-described configuration is, for example, as follows. First, the single cell 110 is manufactured. A method for manufacturing the single cell 110 is, for example, as follows.

(Preparation of green sheet for fuel electrode substrate layer)
With respect to the mixed powder (100 parts by weight) of the NiO powder (50 parts by weight) and the YSZ powder (50 parts by weight), organic beads (15% by weight with respect to the mixed powder) as a pore former, butyral resin, Then, DOP which is a plasticizer, a dispersant, and a toluene + ethanol mixed solvent are added and mixed by a ball mill to prepare a slurry. The organic beads are, for example, spherical particles formed of a polymer such as polymethyl methacrylate or polystyrene. The obtained slurry is thinned by a doctor blade method to produce a plurality of green sheets for a fuel electrode substrate layer having a predetermined thickness. Note that the ratio of the NiO powder and the YSZ powder in the green sheet for the fuel electrode substrate layer can be appropriately changed as long as the performance is satisfied. For example, the NiO powder: YSZ powder may be 60:40 or 40:60. I do not care. That is, the NiO powder can be appropriately changed between 40 to 60 parts by weight so that the mixed powder of the NiO powder and the YSZ powder becomes 100 parts by weight, and the rest can be changed to the YSZ powder.

  Of the plurality of prepared fuel electrode substrate layer green sheets, a pattern corresponding to the arrangement of the current collecting member convex portions 410 is formed on the surface of the fuel electrode substrate layer green sheet corresponding to the specific region SA in the substrate layer 220 described above. Using a mask (considering shrinkage due to firing), low-viscosity NiO is applied to the region corresponding to the first portion PA1 by spraying or printing. After applying the low-viscosity NiO, it is allowed to stand for a predetermined time, so that NiO is impregnated into the target fuel electrode substrate layer green sheet. Thereby, the content rate of NiO in the region corresponding to the first portion PA1 in the fuel electrode substrate layer green sheet corresponding to the specific region SA can be increased, and accordingly, the region corresponding to the first portion PA1. The porosity can be reduced.

(Preparation of green sheet for fuel electrode active layer)
For a mixed powder (100 parts by weight) of NiO powder (60 parts by weight) and YSZ powder (40 parts by weight), butyral resin, DOP as a plasticizer, dispersant, and toluene + ethanol mixed solvent. In addition, the slurry is prepared by mixing with a ball mill. The obtained slurry is thinned by a doctor blade method to produce a green sheet for a fuel electrode active layer having a predetermined thickness (for example, 10 μm to 30 μm). In addition, the ratio of the NiO powder and the YSZ powder of the green sheet for the fuel electrode active layer can be appropriately changed as long as the performance is satisfied. For example, even if the NiO powder: YSZ powder is 50:50 or 40:60 I do not care. That is, the NiO powder can be appropriately changed between 40 to 60 parts by weight so that the mixed powder of the NiO powder and the YSZ powder becomes 100 parts by weight, and the rest can be changed to the YSZ powder.

(Preparation of electrolyte sheet green sheet)
To the YSZ powder (100 parts by weight), a butyral resin, DOP as a plasticizer, a dispersant, and a toluene + ethanol mixed solvent are added and mixed in a ball mill to prepare a slurry. The obtained slurry is thinned by a doctor blade method to produce a green sheet for an electrolyte layer having a predetermined thickness (for example, 10 μm).

(Preparation of a laminate of the electrolyte layer 112 and the fuel electrode 116)
The green sheet for the fuel electrode substrate layer, the green sheet for the fuel electrode active layer, and the green sheet for the electrolyte layer are attached and degreased at about 280 ° C. Furthermore, by firing at about 1350 ° C., a laminate of the electrolyte layer 112 and the fuel electrode 116 (the active layer 210 and the substrate layer 220) is obtained. In the substrate layer 220 of the fuel electrode 116 in the manufactured laminate, the first portion PA1 and the second portion PA2 having the above-described configuration are formed.

(Formation of air electrode 114)
A mixed solution composed of La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ powder and isopropyl alcohol is prepared. The prepared mixed solution is spray-coated on the surface of the electrolyte layer 112 in the laminate and fired at 1100 ° C. to form the air electrode 114. The single cell 110 is manufactured through the above steps.

  Thereafter, the remaining assembly steps (for example, joining of the fuel electrode side current collector 144 and the single cell 110 (fuel electrode 116) or fastening with the bolt 22) are performed. For example, when the fuel electrode side current collector 144 and the single cell 110 (fuel electrode 116) are joined, the surface of the fuel electrode 116 in the single cell 110 on the substrate layer 220 side (current collection member facing surface S1) The paste for the bonding layer is printed on the region facing the electrode facing portion 145 of the fuel electrode side current collector 144 (that is, the surface of the first portion PA1), and the electrode facing portion 145 is pressed against the paste in a predetermined state. By firing under the above conditions, the bonding layer 310 for bonding the electrode facing portion 145 of the fuel electrode side current collector 144 and the substrate layer 220 of the fuel electrode 116 is formed. In addition, the manufacturing of the fuel cell stack 100 having the above-described configuration is completed by performing the remaining assembly steps.

A-5. Effects of this embodiment:
As described above, the current collecting member-single cell complex 107 of the present embodiment is disposed on the fuel cell 116 side of the single cell 110 and the plurality of current collecting members in contact with the surface of the fuel electrode 116. A fuel electrode side current collecting member 400 (fuel electrode side current collector 144, bonding layer 310, interconnector 150) having a convex portion 410 (electrode facing portion 145 of fuel electrode side current collector 144, bonding layer 310). . Further, in the current collecting member-single cell complex 107 of the present embodiment, the fuel electrode 116 (the substrate layer 220 thereof) has the first portion PA1 and the second portion PA2. The first portion PA1 is a part of the protruding portion overlapping area AR1 that overlaps with the current collecting member protruding portion 410 (an assembly of the electrode facing portion 145 and the bonding layer 310) when viewed in the Z direction. That is, the first portion PA1 is a portion where the load from the fuel electrode side current collecting member 400 acts intensively and is a portion located in the main conduction path between the first electrode PA1 and the fuel electrode side current collecting member 400. . The second portion PA2 is a portion that is located next to the first portion PA1 in the direction (plane direction) orthogonal to the Z direction and does not overlap with the current collecting member convex portion 410 when viewed in the Z direction. In the current collecting member-single cell complex 107 of the present embodiment, the first portion PA1 has a lower porosity (vol%) than the second portion PA2.

  As described above, in the current collecting member-single cell complex 107 of the present embodiment, since the plurality of current collecting member convex portions 410 of the fuel electrode side current collecting member 400 are in contact with the surface of the fuel electrode 116, the fuel electrode The load from the side current collecting member 400 acts intensively on each convex overlapping area AR1 in the fuel electrode 116. However, in the current collecting member-single cell complex 107 of the present embodiment, the porosity of the first portion PA1 that is a part of the convex overlap region AR1 where the load from the fuel electrode side current collecting member 400 acts intensively. Therefore, the strength of the first portion PA1 can be increased, and cracking of the single cell 110 due to load concentration from the fuel electrode side current collecting member 400 can be suppressed.

 For example, it is possible to prevent the single cell 110 from cracking by reducing the porosity of the entire specific region SA in the fuel electrode 116. However, in such a configuration, the diffusibility of the fuel gas FG decreases in the entire specific region SA of the fuel electrode 116, and the power generation performance may be reduced. On the other hand, in the current collecting member-single cell complex 107 of the present embodiment, the porosity of only the first portion PA1 overlapping the current collecting member convex portion 410 when viewed in the Z direction in the specific area SA of the fuel electrode 116. The second portion PA2 that does not overlap with the current collecting member convex portion 410 as viewed in the Z direction is maintained in a high porosity state. Therefore, in the current collecting member-single cell complex 107 of the present embodiment, it is possible to suppress the occurrence of cracking of the single cell 110 while suppressing a decrease in the diffusibility of the fuel gas FG in the fuel electrode 116.

  Further, in the current collecting member-single cell complex 107 of the present embodiment, the fuel electrode 116 includes a conductive metal (Ni), and the content (vol%) of the conductive metal in the first portion PA1 is the second. It is higher than the content of the conductive metal in the portion PA2. Therefore, according to the current collecting member-single cell complex 107 of the present embodiment, the conductive metal of the first portion PA1 located in the main conduction path between the fuel electrode 116 and the fuel electrode side current collecting member 400. Therefore, the conductivity of the single cell 110 can be improved.

  Further, in the current collecting member-single cell complex 107 of the present embodiment, the fuel electrode 116 includes particles of oxide ion conductive ceramics (YSZ), and includes the oxide ion conductive ceramic particles of the first portion PA1. The rate (vol%) is higher than the content of the oxide ion conductive ceramic particles in the second portion PA2. Therefore, according to the current collecting member-single cell complex 107 of the present embodiment, the strength of the first portion PA1, which is a portion where the load from the fuel electrode side current collecting member 400 acts intensively, is effectively improved. Therefore, it is possible to effectively prevent the single cell 110 from cracking.

  Further, in the current collecting member-single cell complex 107 of the present embodiment, the ratio of the thickness Tx of the region occupied by the first portion PA1 to the thickness To of the entire fuel electrode 116 (the protruding portion overlapping region AR1). Is 50% or less. Therefore, according to the current collecting member-single cell complex 107 of the present embodiment, cracking of the single cell 110 occurs while suppressing a decrease in gas diffusibility by keeping the porosity of the fuel electrode 116 as a whole to some extent. This can be suppressed.

  Further, in the current collecting member-single cell complex 107 of the present embodiment, the fuel electrode 116 has a plurality of first portions PA1 that overlap with each of the plurality of current collecting member convex portions 410 when viewed in the Z direction. Therefore, according to the current collecting member-single cell complex 107 of the present embodiment, a plurality of high-strength first portions PA1 are arranged side by side in the surface direction while suppressing a decrease in gas diffusibility of the fuel electrode 116 as a whole. Thereby, generation | occurrence | production of the crack of the single cell 110 can be suppressed still more effectively.

A-6. Analysis method of fuel electrode 116:
The method for analyzing the fuel electrode 116 is, for example, as follows.

(Method for specifying content of conductive metal and oxide ion conductive ceramic particles)
The content of the conductive metal or oxide ion conductive ceramic particles at each position (each region) of the fuel electrode 116 is specified by the following method. An element mapping image (for example, 5000 times) by FIB-SEM (acceleration voltage 1.5 kV) is set at a position (region) where the content rate in the cross section is to be specified by setting a cross section of the single cell 110 orthogonal to the plane direction. obtain. By calculating the area ratio of the corresponding element at the position (region) in the obtained image, the content ratio of the conductive metal or oxide ion conductive ceramic particles is specified.

(Porosity identification method)
The porosity at each position (each region) of the fuel electrode 116 is specified by the following method. In the same manner as the content rate specifying method described above, an SEM image (for example, 5000 times) obtained by FIB-SEM is obtained, and a plurality of lines parallel to the surface direction are arranged at predetermined intervals at the position (region) in the obtained image. (Eg, 1 μm to 5 μm intervals). The length of the portion corresponding to the pores on each straight line is measured, and the ratio of the total length of the portions corresponding to the pores to the total length of the straight line is defined as the porosity on the line. By calculating the average value of the porosity in a plurality of straight lines drawn to the position (region) where the porosity is to be specified, the porosity at the position (region) is specified.

  As shown in FIG. 6, in the cross section of the fuel electrode 116, a thickness Tw (for example, 10 μm) that overlaps with the front end surface of the current collecting member convex portion 410 (that is, located in the convex overlapping region AR1) as viewed in the Z direction. ) And the first window W1 in the Z direction as viewed in the Z direction (ie, located in the non-overlapping region AR2) and adjacent to the first window W1 in the surface direction. A pair with the second window W2 having a thickness Tw is set in order while shifting by a predetermined distance (for example, 1 μm) in the Z direction, and is defined by the porosity of the region defined by the first window W1 and the second window W2. The porosity of the area to be determined is specified. In a certain pair of the first window W1 and the second window W2, when the porosity of the region defined by the first window W1 is lower than the porosity of the region defined by the second window W2, the first window The region defined by W1 corresponds to the first portion PA1, and the region defined by the second window W2 corresponds to the second portion PA2.

(Identification method of thickness Tx of 1st part PA1)
The thickness Tx of the first portion PA1 in the first embodiment is specified by the following method. As shown in the upper part of FIG. 7, the curve C (L1) indicating the porosity at each position on the imaginary line L1 is substantially linear from the intersection P11 with the current collecting member facing surface S1 in the positive direction of the Z axis. The porosity decreases in the vicinity of the boundary between the other part and the first part PA1, and then becomes substantially linear again in the first part PA1. An imaginary line Lm that is equidistant from the two substantially linear portions of the curve C (L1) is specified, an intersection of the imaginary line Lm and the curve C (L1) is specified, and the position of the intersection (point P12) The distance from the substrate layer 220 to the point P13 on the interface BO between the substrate layer 220 and the active layer 210 is specified as the thickness Tx of the first portion PA1.

B. Second embodiment:
FIG. 8 is an explanatory diagram showing a detailed configuration of the fuel electrode 116a in the second embodiment. Hereinafter, among the configurations of the fuel electrode 116a (single cell 110a) in the second embodiment, the same reference numerals are given to the same configurations as those of the fuel electrode 116 (single cell 110) in the first embodiment described above. Therefore, the description thereof is omitted as appropriate.

  As shown in FIG. 8, in the second embodiment, the position of the specific region SA in the fuel electrode 116a is different from that in the first embodiment described above. Specifically, in the second embodiment, the specific area SA is an area having a thickness Tx from the current collecting member facing surface S1 in the substrate layer 220. Also in the second embodiment, in the specific area SA, the first portion PA1 that overlaps the front end surface of the current collector member convex portion 410 when viewed in the Z direction overlaps with the front end surface of the current collector member convex portion 410 when viewed in the Z direction. Compared with the second portion PA2 that does not become, the porosity is low, the content of conductive metal is high, and the content of oxide ion conductive ceramic particles is high.

  In the current collecting member-single cell complex 107 including the single cell 110a and the fuel electrode side current collecting member 400 of the second embodiment, as in the current collecting member-single cell complex 107 of the first embodiment described above, Since the porosity of the first part PA1, which is the part where the load from the fuel electrode side current collecting member 400 acts intensively, is low, the strength of the first part PA1 can be increased, and the fuel electrode side current collecting member It is possible to prevent the single cell 110a from cracking due to load concentration from 400. Further, in the current collecting member-single cell complex 107 of the second embodiment, the porosity of only the first portion PA1 that overlaps the current collecting member convex portion 410 as viewed in the Z direction in the specific area SA of the fuel electrode 116a. Since the porosity of the second portion PA2 that is lowered and does not overlap with the current collector projection 410 as viewed in the Z direction is maintained at a high level, the diffusibility of the fuel gas FG in the fuel electrode 116a is reduced. Can be suppressed.

  Further, in the current collecting member-single cell complex 107 of the second embodiment, the conductive metal content of the first part PA1 is the conductive metal of the second part PA2, as in the first embodiment described above. Therefore, in the fuel electrode 116a, the content of the conductive metal in the first portion PA1 located in the main conduction path between the fuel electrode 116a and the fuel electrode side current collecting member 400 can be increased. The conductivity of 110a can be improved.

  Moreover, in the current collection member-single cell complex 107 of the second embodiment, the content of the oxide ion conductive ceramic particles in the first portion PA1 is the second portion PA2 as in the first embodiment described above. Therefore, the strength of the first portion PA1, which is a portion where the load from the fuel electrode side current collecting member 400 acts intensively, can be effectively improved. Further, it is possible to effectively prevent the single cell 110a from being cracked due to the load concentration from the fuel electrode side current collecting member 400.

  Further, in the current collecting member-single cell complex 107 of the second embodiment, the thickness of the region occupied by the first portion PA1 with respect to the total thickness To of the fuel electrode 116a, as in the first embodiment described above. Since the ratio of Tx is 50% or less, it is possible to suppress the occurrence of cracking of the single cell 110a while suppressing the decrease in gas diffusivity by maintaining the porosity of the fuel electrode 116a as a whole to some extent. Can do.

  Further, in the current collecting member-single cell complex 107 of the second embodiment, as in the first embodiment described above, the fuel electrode 116a overlaps each of the plurality of current collecting member convex portions 410 when viewed in the Z direction. Since the first portion PA1 is provided, cracking of the single cell 110a is generated by providing a plurality of high-strength first portions PA1 arranged in the plane direction while suppressing a decrease in gas diffusibility as a whole of the fuel electrode 116a. Can be more effectively suppressed.

  Note that the thickness Tx of the first portion PA1 in the second embodiment is specified by the following method. FIG. 9 is an explanatory diagram showing a method for specifying the thickness Tx of the first portion PA1 in the second embodiment. In FIG. 9, in the cross section of the fuel electrode 116a of the second embodiment, a curve C (L1) indicating the porosity at each position on an imaginary line L1 (see FIG. 8) that equally divides the convex overlap region AR1 in the surface direction. )It is shown. As shown in FIG. 9, in the second embodiment, the curve C (L1) is substantially linear in the first part PA1 disposed on the current collecting member facing surface S1 side, and the first part PA1 and the other part The porosity increases in the vicinity of the boundary with the part, and then becomes substantially linear again in the other part. A virtual line Lm that is equidistant from the two substantially linear portions of the curve C (L1) is specified, an intersection point between the virtual line Lm and the curve C (L1) is specified, and a current collecting member is determined from the position of the intersection point The distance to the facing surface S1 is specified as the thickness Tx of the first portion PA1.

C. Third embodiment:
FIG. 10 is an explanatory diagram showing a detailed configuration of the fuel electrode 116b in the third embodiment. Hereinafter, among the configurations of the fuel electrode 116b (single cell 110b) in the third embodiment, the same reference numerals are given to the same configurations as those of the fuel electrode 116 (single cell 110) in the first embodiment described above. Therefore, the description thereof is omitted as appropriate.

  As shown in FIG. 10, the third embodiment is different from the first embodiment described above in that the entire fuel electrode 116 b is a specific region SA. That is, in the third embodiment, all portions from the current collecting member facing surface S1 to the electrolyte layer facing surface S2 in the convex overlapping region AR1 of the fuel electrode 116b are the first portion PA1, and the convex portion of the fuel electrode 116b. All portions from the current collecting member facing surface S1 to the electrolyte layer facing surface S2 in the non-overlapping region AR2 are second portions PA2. Also in the third embodiment, in the specific area SA, the first portion PA1 that overlaps the front end surface of the current collector member convex portion 410 when viewed in the Z direction overlaps with the front end surface of the current collector member convex portion 410 when viewed in the Z direction. Compared with the second portion PA2 that does not become, the porosity is low, the content of conductive metal is high, and the content of oxide ion conductive ceramic particles is high.

  In the current collecting member-single cell complex 107 including the single cell 110b and the fuel electrode side current collecting member 400 of the third embodiment, as in the current collecting member-single cell complex 107 of the first embodiment described above, Since the porosity of the first part PA1, which is the part where the load from the fuel electrode side current collecting member 400 acts intensively, is low, the strength of the first part PA1 can be increased, and the fuel electrode side current collecting member It is possible to prevent the single cell 110b from being cracked due to load concentration from 400. In particular, in the current collecting member-single cell complex 107 of the third embodiment, all the portions from the current collecting member facing surface S1 to the electrolyte layer facing surface S2 in the convex overlapping region AR1 of the fuel electrode 116b have a porosity. Since the first portion PA1 is low, it is possible to effectively prevent the single cell 110b from cracking. Further, in the current collecting member-single cell complex 107 of the third embodiment, the porosity of only the first portion PA1 that overlaps the current collecting member convex portion 410 as viewed in the Z direction in the specific area SA of the fuel electrode 116b. Since the porosity of the second portion PA2 that is lowered and does not overlap with the current collecting member convex portion 410 when viewed in the Z direction is maintained in a high state, the diffusibility of the fuel gas FG in the fuel electrode 116b is reduced. Can be suppressed.

  Further, in the current collecting member-single cell complex 107 according to the third embodiment, the conductive metal content of the first part PA1 is equal to that of the second part PA2, as in the first embodiment described above. Therefore, in the fuel electrode 116b, the content of the conductive metal in the first portion PA1 located in the main conduction path between the fuel electrode 116b and the fuel electrode side current collecting member 400 can be increased. The conductivity of 110b can be improved. In particular, in the current collecting member-single cell complex 107 of the third embodiment, all the portions from the current collecting member facing surface S1 to the electrolyte layer facing surface S2 in the convex overlapping region AR1 of the fuel electrode 116b are electrically conductive metal. Therefore, the conductivity of the single cell 110b can be effectively improved.

  Moreover, in the current collection member-single cell complex 107 of the third embodiment, the content of the oxide ion conductive ceramic particles in the first portion PA1 is the second portion PA2 as in the first embodiment described above. Therefore, the strength of the first portion PA1, which is a portion where the load from the fuel electrode side current collecting member 400 acts intensively, can be effectively improved. Further, it is possible to effectively prevent the single cell 110b from cracking due to the load concentration from the fuel electrode side current collecting member 400. In particular, in the current collecting member-single cell complex 107 of the third embodiment, all the portions from the current collecting member facing surface S1 to the electrolyte layer facing surface S2 in the convex overlapping region AR1 of the fuel electrode 116b are oxide ions. Since it becomes 1st part PA1 with a high content rate of electroconductive ceramic particle, it can suppress effectively that the crack of the single cell 110b generate | occur | produces.

  Further, in the current collecting member-single cell complex 107 of the third embodiment, as in the first embodiment described above, the fuel electrode 116b overlaps each of the plurality of current collecting member convex portions 410 when viewed in the Z direction. Since the first portion PA1 is provided, cracks in the single cell 110b are generated by providing a plurality of high-strength first portions PA1 arranged in the plane direction while suppressing a decrease in gas diffusibility as a whole of the fuel electrode 116b. Can be more effectively suppressed.

D. Fourth embodiment:
FIG. 11 is an explanatory diagram showing a detailed configuration of the fuel electrode 116c in the fourth embodiment. Hereinafter, among the configurations of the fuel electrode 116c (single cell 110c) in the fourth embodiment, the same reference numerals are given to the same configurations as those of the fuel electrode 116 (single cell 110) in the first embodiment described above. Therefore, the description thereof is omitted as appropriate.

  As shown in FIG. 11, the fourth embodiment differs from the first embodiment described above in that two specific regions SA exist in the fuel electrode 116c. Specifically, in the fourth embodiment, the fuel electrode 116c has a first specific region SA1 that is a region having a thickness Tx (1) from the interface BO with the active layer 210 in the substrate layer 220, and There is a second specific region SA2 that is a region having a thickness Tx (2) from the current collecting member facing surface S1. Also in the fourth embodiment, in each specific area SA, the first portion PA1 overlapping the front end surface of the current collecting member convex portion 410 when viewed in the Z direction is the same as the front end surface of the current collecting member convex portion 410 when viewed in the Z direction. Compared with the second portion PA2 that does not overlap, the porosity is low, the content of conductive metal is high, and the content of oxide ion conductive ceramic particles is high.

  In the fourth embodiment, the total thickness Tx of the region occupied by the first part PA1 in each specific region SA (= Tx (1) + Tx (2)) with respect to the thickness To of the entire fuel electrode 116c. The ratio is 50% or less.

  In the current collecting member-single cell complex 107 including the single cell 110c and the fuel electrode side current collecting member 400 of the fourth embodiment, as in the current collecting member-single cell complex 107 of the first embodiment described above, Since the porosity of the first part PA1, which is the part where the load from the fuel electrode side current collecting member 400 acts intensively, is low, the strength of the first part PA1 can be increased, and the fuel electrode side current collecting member It is possible to prevent the single cell 110c from being cracked due to load concentration from 400. In particular, in the current collecting member-single cell complex 107 according to the fourth embodiment, since there are two first portions PA1 having a low porosity in each convex portion overlapping area AR1, the single cell 110c is cracked. This can be effectively suppressed. Further, in the current collecting member-single cell complex 107 of the fourth embodiment, the porosity of only the first portion PA1 that overlaps the current collecting member convex portion 410 as viewed in the Z direction in the specific area SA of the fuel electrode 116c. Since the porosity of the second portion PA2 that is lowered and does not overlap with the current collecting member convex portion 410 as viewed in the Z direction is maintained at a high level, the diffusibility of the fuel gas FG in the fuel electrode 116c is reduced. Can be suppressed.

  Moreover, in the current collection member-single cell complex 107 of the fourth embodiment, the conductive metal content (vol%) of the first portion PA1 is the second portion PA2 as in the first embodiment described above. In the fuel electrode 116c, the content of the conductive metal in the first portion PA1 located in the main conduction path between the fuel electrode 116c and the fuel electrode side current collecting member 400 may be increased. In addition, the conductivity of the single cell 110c can be improved. In particular, in the current collecting member-single cell complex 107 according to the fourth embodiment, each of the convex portion overlapping areas AR1 includes two first portions PA1 having a high conductive metal content. The conductivity can be effectively improved.

  Moreover, in the current collection member-single cell complex 107 of the fourth embodiment, the content rate (vol%) of the oxide ion conductive ceramic particles in the first portion PA1 is the same as in the first embodiment described above. Since the content of the oxide ion conductive ceramic particles in the second portion PA2 is higher, the strength of the first portion PA1, which is a portion where the load from the fuel electrode side current collecting member 400 acts intensively, is effectively improved. Therefore, it is possible to effectively prevent the single cell 110c from being cracked due to load concentration from the fuel electrode side current collecting member 400. In particular, in the current collecting member-single cell complex 107 of the fourth embodiment, there are two first portions PA1 having a high content of oxide ion conductive ceramic particles in each convex portion overlapping area AR1, The occurrence of cracking of the single cell 110c can be effectively suppressed.

  In the current collecting member-single cell complex 107 of the fourth embodiment, the thickness of the region occupied by the first portion PA1 with respect to the total thickness To of the fuel electrode 116c is the same as in the first embodiment described above. Since the total ratio of Tx is 50% or less, the porosity of the fuel electrode 116c as a whole is kept high to a certain extent, thereby suppressing a decrease in gas diffusibility and suppressing the occurrence of cracks in the single cell 110c. can do.

  Further, in the current collecting member-single cell complex 107 of the fourth embodiment, as in the first embodiment described above, the fuel electrode 116c is overlapped with each of the plurality of current collecting member convex portions 410 when viewed in the Z direction. Since the first portion PA1 is provided, cracks in the single cell 110c are generated by providing a plurality of high-strength first portions PA1 arranged in the plane direction while suppressing a decrease in gas diffusibility as the entire fuel electrode 116c. Can be more effectively suppressed.

E. Example:
FIG. 12 is an explanatory diagram showing a configuration of an example of the current collecting member-single cell complex 107 of each embodiment described above. In FIG. 12, for each of Examples 1 to 3, the content of conductive metal (Ni), the content of oxide ion conductive ceramics (YSZ) particles in the first part PA1 and the second part PA2, The porosity is shown.

  In Examples 1 and 3, the first portion PA1 has a lower porosity and a higher conductive metal content than the second portion PA2. Note that the content of the oxide ion conductive ceramic particles is substantially the same in the first portion PA1 and the second portion PA2. Therefore, in Example 1, while suppressing the fall of the diffusibility of the fuel gas FG in the fuel electrode 116, it can suppress that the single cell 110 cracks, and improves the electroconductivity of the single cell 110. be able to.

  In Example 2, the first part PA1 has a lower porosity, a higher content of conductive metal, and a higher content of oxide ion conductive ceramic particles than the second part PA2. Therefore, in Example 2, while suppressing the fall of the diffusibility of the fuel gas FG in the fuel electrode 116, it can suppress effectively that the crack of the single cell 110 generate | occur | produces, and the electroconductivity of the single cell 110 is also possible. Can be improved.

F. Variations:
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 gist thereof. For example, the following modifications are possible.

  The configuration of the fuel cell stack 100 in the above embodiment is merely an example, and various modifications can be made. For example, in the above embodiment, the fuel electrode 116 is configured by two layers of the active layer 210 and the substrate layer 220. However, the fuel electrode 116 may have a single-layer configuration, or by three or more layers. It may be configured.

  Moreover, in the said embodiment, the position of specific area | region SA in the fuel electrode 116 is an example to the last, and can deform | transform variously. For example, in the first embodiment, the specific area SA is an area having a thickness Tx from the interface BO with the active layer 210 in the substrate layer 220. In the second embodiment, the specific area SA is in the substrate layer 220. Although it is assumed that the region has a thickness Tx from the current collecting member facing surface S1, as shown in FIG. 13, the specific region SA is also from the interface BO with the active layer 210 in the substrate layer 220 from the current collecting member facing surface S1. It may be a region separated from

  Further, the thickness Tx of the first portion PA1 in the modification shown in FIG. 13 is specified by the following method. FIG. 14 is an explanatory diagram showing a method for specifying the thickness Tx of the first portion PA1 in the modification shown in FIG. FIG. 14 shows a curve C indicating the porosity at each position on an imaginary line L1 (see FIG. 13) equally dividing the convex overlap region AR1 in the plane direction in the cross section of the fuel electrode 116 of the modified example shown in FIG. (L1) is shown. As shown in FIG. 14, the curve C (L1) is substantially linear from the current collecting member facing surface S1 in the positive Z-axis direction, and the porosity is in the vicinity of the boundary between the other part and the first part PA1. After that, the first portion PA1 becomes substantially straight again. An imaginary line Lm1 that is equidistant from these two substantially linear portions in the curve C (L1) is identified, and the intersection of the imaginary line Lm1 and the curve C (L1) (when there are a plurality of intersections, the current collecting member faces) (The intersection point closest to the surface S1) is specified, and the position of the intersection point is defined as the boundary of the first part PA1 on the current collecting member facing surface S1 side. Further, as shown in FIG. 14, the curve C (L1) is near the boundary between the first part PA1 and the other part from the substantially linear part in the first part PA1 toward the positive direction of the Z-axis. The porosity increases and becomes substantially linear again in other parts. An imaginary line Lm2 that is equidistant from these two substantially linear portions in the curve C (L1) is identified, and the intersection of the imaginary line Lm2 and the curve C (L1) (if there are multiple intersections, the interface BO is the most). A near intersection (except for an intersection on the interface BO) is specified, and the position of the intersection is set as a boundary on the interface BO side of the first portion PA1. The distance between the two boundaries described above is specified as the thickness Tx of the first portion PA1.

  In the above embodiment, the bonding layer 310 is interposed between the electrode facing portion 145 of the fuel electrode side current collector 144 and the current collecting member facing surface S1 of the fuel electrode 116, but the bonding layer 310 is provided. Instead, the electrode facing portion 145 of the fuel electrode side current collector 144 may be in direct contact with the current collecting member facing surface S1 of the fuel electrode 116. That is, the current collecting member convex portion 410 may be configured by the electrode facing portion 145. Even in such a configuration, if the porosity in the first portion PA1 of the fuel electrode 116 is lower than the porosity in the second portion PA2, the occurrence of cracks in the single cell 110 can be suppressed.

  In addition, the configuration of the fuel electrode side current collector 144 in the above embodiment is merely an example, and various changes can be made. For example, the fuel electrode side current collector 144 has the same configuration as the integrated member of the air electrode side current collector 134 and the interconnector 150 in the above embodiment, that is, a flat plate portion (interconnector 150) orthogonal to the Z direction. And a plurality of convex portions (air electrode side current collector 134) formed so as to protrude from the flat plate portion toward the fuel electrode 116. In such a configuration, the surface of the flat plate portion opposite to the side on which the plurality of convex portions are formed may be a surface on which irregularities are formed instead of a flat surface.

  Further, in the above-described embodiment, for all the first portions PA1 in the fuel electrode 116, the porosity in the first portion PA1 is lower than the porosity in the second portion PA2 adjacent to the first portion PA1. However, such a configuration is not necessarily required. With respect to at least one first portion PA1 in the fuel electrode 116, the porosity in the first portion PA1 may be lower than the porosity in the second portion PA2 adjacent to the first portion PA1. With such a configuration, the occurrence of cracks in the single cell 110 in the vicinity of the position of the first portion PA1 can be suppressed. In order to effectively suppress the occurrence of cracks in the unit cell 110, the porosity in the first portion PA1 is about 50% or more of all the first portions PA1 in the fuel electrode 116. The porosity is preferably lower than the porosity of the second portion PA2 adjacent to the portion PA1. When the number of first portions PA1 in the fuel electrode 116 is 20 or less, the porosity is specified for all the first portions PA1 by the specifying method. Further, when the number of the first portions PA1 in the fuel electrode 116 exceeds 20, the porosity is specified for any 20 first portions PA1 by the specifying method, and the specified porosity is set. Based on this, the configuration of the other first part PA1 is estimated.

  In each of the above embodiments, the conductive metal content (vol%) of the first part PA1 is higher than the conductive metal content (vol%) of the second part PA2. For example, the content of the conductive metal in the first portion PA1 may be equal to the content of the conductive metal in the second portion PA2. Moreover, in the said embodiment, the content rate (vol%) of the oxide ion conductive ceramic particle of 1st part PA1 is from the content rate (vol%) of the oxide ion conductive ceramic particle of 2nd part PA2. Although it is said that it is high, it is not always necessary to have such a relationship. For example, the content of the oxide ion conductive ceramic particles in the first portion PA1 is the content of the oxide ion conductive ceramic particles in the second portion PA2. It may be equal to the rate.

  Further, instead of the fuel electrode 116 or together with the fuel electrode 116, the air electrode 114 may have the same configuration as the fuel electrode 116 described above. That is, the air electrode 114 is a first part that is at least a part of a region (convex overlapping region) that overlaps the air electrode side current collector 134 when viewed in the Z direction, and is adjacent to the first part in the plane direction. It is good also as a structure which has a 1st part in which a porosity is lower than the 2nd part which is located and does not overlap with the air electrode side electrical power collector 134 by Z direction view. In this way, it is possible to suppress the occurrence of cracking of the single cell 110 while suppressing the decrease in diffusibility of the oxidant gas OG in the air electrode 114, and to improve the conductivity of the single cell 110. be able to.

  In the above embodiment, the number of unit cells 110 included in the fuel cell stack 100 is merely an example, and the number of unit cells 110 is appropriately determined according to the output voltage required for the fuel cell stack 100 or the like.

  Moreover, the material which forms each member in the said embodiment is an illustration to the last, and each member may be formed with another material. For example, in the above embodiment, the fuel electrode 116 is formed by cermet of Ni which is a conductive metal and YSZ particles which are oxide ion conductive ceramics. However, a metal other than Ni is used as the conductive metal. (For example, Cu or Mo) may be used, and ceramics other than YSZ (for example, CSZ or ScSZ) may be used as the oxide ion conductive ceramic.

  In the present specification, the fact that the member B and the member C are opposed to each other across the member (or a part having the member, the same applies hereinafter) A is not limited to the form in which the member A and the member B or the member C are adjacent to each other. It includes a form in which another component is interposed between member A and member B or member C. For example, another layer may be provided between the electrolyte layer 112 and the air electrode 114. Even with such a configuration, it can be said that the air electrode 114 and the fuel electrode 116 face each other with the electrolyte layer 112 interposed therebetween.

  Further, the method of manufacturing the fuel cell stack 100 in the above embodiment is merely an example, and various modifications can be made. For example, in the above-described embodiment, the application of the low-viscosity NiO to the surface of the specific fuel electrode substrate layer green sheet is performed before the firing step for producing the laminate of the electrolyte layer 112 and the fuel electrode 116. However, the low-viscosity NiO may be applied after the firing step. Further, in order to form the first portion PA1 having a low porosity in the fuel electrode 116, it is not always necessary to apply a conductive metal or an oxide thereof (for example, NiO). The single cell 110 may be manufactured.

  In the above embodiment, the SOFC that generates electricity using the electrochemical reaction between hydrogen contained in the fuel gas and oxygen contained in the oxidant gas is targeted. The present invention can be similarly applied to an electrolytic single cell that is a constituent unit of a solid oxide electrolytic cell (SOEC) that generates hydrogen by using hydrogen, and an electrolytic cell stack including a plurality of electrolytic single cells. The configuration of the electrolytic cell stack is well known as described in, for example, Japanese Patent Application Laid-Open No. 2014-207120 and will not be described in detail here. However, the configuration is generally the same as that of the fuel cell stack 100 in the above-described embodiment. It is a configuration. That is, the fuel cell stack 100 in the above-described embodiment may be read as an electrolytic cell stack, the power generation unit 102 may be read as an electrolytic cell unit, and the single cell 110 may be read as an electrolytic single cell. However, when the electrolysis cell stack is operated, 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). 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 of the electrolysis cell stack through the communication hole.

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

22: Bolt 24: Nut 26: Insulating sheet 27: Gas passage member 28: Body portion 29: Branch portion 100: Fuel cell stack 102: Fuel cell power generation unit 104: End plate 106: End plate 107: Current collecting member-fuel cell Single cell composite 108: Communication hole 110: Single cell 112: Electrolyte layer 114: Air electrode 116: Fuel electrode 120: Separator 121: Hole 124: Junction 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 140: Fuel electrode side frame 141: Hole 142: Fuel gas supply communication hole 143: Fuel gas discharge communication hole 144: Fuel electrode Side current collector 145: Electrode facing portion 146: Interconnector facing portion 147: Connection 149: Spacer 150: Interconnector 161: Oxidant gas introduction manifold 162: Oxidant gas discharge manifold 166: Air chamber 171: Fuel gas introduction manifold 172: Fuel gas discharge manifold 176: Fuel chamber 210: Active layer 220: Substrate layer 310: Bonding layer 400: Fuel electrode side current collecting member 410: Current collecting member convex portion

Claims (8)

An electrochemical reaction unit cell including an electrolyte layer and an air electrode and a fuel electrode facing each other in the first direction across the electrolyte layer, and at least one of the air electrode and the fuel electrode of the electrochemical reaction unit cell In the current collecting member-electrochemical reaction single cell complex comprising: a current collecting member that is disposed on the specific electrode side and has a plurality of convex portions that are in contact with the surface of the specific electrode.
The specific electrode is a first portion that is at least a part of a convex overlapping region that overlaps the convex when viewed in the first direction, and the first electrode in a second direction orthogonal to the first direction. And a first portion having a lower porosity than a second portion that is located next to the second portion and does not overlap the convex portion when viewed in the first direction. Chemical reaction single cell complex. In the current collection member-electrochemical reaction single cell complex according to claim 1,
The specific electrode includes a conductive metal,
The current collecting member-electrochemistry, wherein the content (vol%) of the conductive metal in the first portion is higher than the content (vol%) of the conductive metal in the second portion. Reaction single cell complex. In the current collection member-electrochemical reaction single cell complex according to claim 1 or 2,
The specific electrode includes oxide ion conductive ceramic particles,
The content (vol%) of the oxide ion conductive ceramic particles in the first portion is higher than the content (vol%) of the oxide ion conductive ceramic particles in the second portion. A current collecting member-electrochemical reaction single cell composite. In the current collection member-electrochemical reaction single cell complex according to any one of claims 1 to 3,
The first part is the entire part from the surface on the electrolyte layer side to the surface on the current collecting member side in the convex overlapping region, and the current collecting member-electrochemical reaction single cell composite body. In the current collection member-electrochemical reaction single cell complex according to any one of claims 1 to 3,
In the first direction, the ratio of the thickness of the region occupied by the first portion in the convex overlap region to the thickness of the convex overlap region is 50% or less, Current collecting member-electrochemical reaction single cell composite. In the current collection member-electrochemical reaction single cell complex according to any one of claims 1 to 5,
The specific electrode has a plurality of the first portions, and is a current collecting member-electrochemical reaction single cell composite. In the current collection member-electrochemical reaction single cell complex according to claim 6,
The current collecting member-electrochemical reaction single cell complex, wherein the specific electrode has a plurality of the first portions overlapping with the plurality of convex portions as viewed in the first direction. In an electrochemical reaction cell stack comprising a plurality of current collecting members-electrochemical reaction single cell composites arranged side by side in the first direction,
At least one of the plurality of current collecting members-electrochemical reaction single cell composites is the current collecting member-electrochemical reaction single cell composites according to any one of claims 1 to 7. An electrochemical reaction cell stack.

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