JP6734707B2 - Current collecting member-electrochemical reaction single cell composite and electrochemical reaction cell stack - Google Patents

Description

The technology disclosed herein relates to a current collecting member-electrochemical reaction single cell composite.

A solid oxide fuel cell (hereinafter referred to as "SOFC") having an electrolyte layer containing a solid oxide is known as one of the types of fuel cells that generate electricity by utilizing an electrochemical reaction between hydrogen and oxygen. 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 the electric energy obtained by the power generation reaction in the single cell. The current collecting member is configured to have a plurality of convex portions in contact with the surface of the electrode in order to exhibit a current collecting function without disturbing the supply of the reaction gas into the electrode (see, for example, Patent Document 1). .. In the present specification, a structure composed of a single cell and a current collecting member is referred to as a current collecting member-fuel cell single cell composite body.

JP, 2014-216297, A

In the conventional current collecting member-fuel cell single cell composite, 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 contacts the plurality of convex portions of the electrode. There is a risk that the single cell may be cracked and a single cell may crack.

In addition, such a problem is caused by an electrolytic single cell, which is a constituent unit of a solid oxide type electrolytic cell (hereinafter, referred to as “SOEC”) that generates hydrogen by utilizing an electrolysis reaction of water, and a current collecting member. This is also a common problem in 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 current collecting member-electrochemical reaction single cell composite. Further, such a problem is not limited to SOFCs and SOECs, and is a problem common to current collector-electrochemical reaction single cell composites composed of other types of electrochemical reaction single cells and current collectors. is there.

This specification discloses a technique capable of solving the above-mentioned problems.

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

(1) A current collecting member-electrochemical reaction single cell composite disclosed in the present specification is an electrochemical including an electrolyte layer and an air electrode and a fuel electrode that face each other in a first direction with the electrolyte layer interposed therebetween. A reaction single cell, a current collecting member having a plurality of convex portions arranged on the specific electrode side which is at least one of the air electrode and the fuel electrode of the electrochemical reaction single cell, and which is in contact with the surface of the specific electrode, In the current collecting member-electrochemical reaction single cell composite body, the specific electrode is a first portion that is at least a part of a protrusion overlapping region that overlaps the protrusion in the first direction, A first portion that is located next to the first portion in a second direction orthogonal to the first direction and that has a lower porosity than a second portion that is a portion that does not overlap the convex portion in the first direction view. Has a part. According to the current collecting member-electrochemical reaction single cell composite body, in the specific electrode, 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, is low. Therefore, the strength of the first portion can be increased, and the occurrence of cracks in the electrochemical reaction single cell due to the load concentration from the current collector can be suppressed. Further, in the specific electrode, since the second portion that does not overlap the convex portion in the first direction has a high porosity, it is possible to suppress the decrease in the diffusibility of the reaction gas in the specific electrode.

(2) In the current collecting member-electrochemical reaction single cell composite body, the specific electrode includes a conductive metal, and the content rate (vol%) of the conductive metal in the first portion is the second level. The constitution may be higher than the content rate (vol%) of the conductive metal in the portion. According to the current collecting member-electrochemical reaction single cell composite body, in the specific electrode, the content ratio 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. It is possible to improve the conductivity of the electrochemical reaction single cell.

(3) In the current collecting member-electrochemical reaction single cell composite, the specific electrode includes oxide ion conductive ceramic particles, and the content ratio 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 body, in the specific electrode, the strength of the first portion, which is a portion where the load from the current collecting member acts intensively, can be effectively improved. The generation of cracks in the electrochemical reaction single cell can be effectively suppressed.

(4) In the current collecting member-electrochemical reaction single cell composite body, 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 overlapping region. It may have a certain configuration. According to the current collecting member-electrochemical reaction single cell composite body, all the portions from the surface on the electrolyte layer side to the surface on the current collecting member side in the protrusion overlapping region of the specific electrode are the first portions having low porosity. Therefore, the occurrence of cracks in the electrochemical reaction single cell can be effectively suppressed.

(5) In the current collecting member-electrochemical reaction single cell composite body, in the first direction, of a region occupied by the first portion in the convex overlapping region with respect to a 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 body, cracking of the electrochemical reaction single cell is suppressed while suppressing a decrease in gas diffusibility 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 first portions. According to the current collecting member-electrochemical reaction single cell composite body, by providing a plurality of first portions having high strength while suppressing a decrease in gas diffusibility of the specific electrode as a whole, the electrochemical reaction single cell composite The generation of cracks can be effectively suppressed.

(7) In the current collecting member-electrochemical reaction single cell composite body, the specific electrode may have a plurality of first portions that overlap with the plurality of convex portions in the first direction. Good. According to the current collecting member-electrochemical reaction single cell composite body, while suppressing a decrease in gas diffusibility of the specific electrode as a whole, a plurality of first portions having high strength are arranged in a direction orthogonal to the first direction. By providing it, it is possible to more effectively suppress the occurrence of cracks in the electrochemical reaction single cell.

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

FIG. 3 is a perspective view showing an external configuration of the fuel cell stack 100 according to the first embodiment. FIG. 2 is an explanatory diagram showing an XZ sectional configuration of the fuel cell stack 100 at a position II-II in FIG. 1. It is explanatory drawing which shows the YZ cross-section structure of the fuel cell stack 100 in the position of III-III of FIG. FIG. 3 is an explanatory diagram showing an XZ sectional configuration of two power generation units 102 adjacent to each other at the same position as the section shown in FIG. 2. It is explanatory drawing which shows the YZ cross-section structure of two adjacent power generation units 102 in the same position as the cross section shown in FIG. FIG. 3 is an explanatory diagram showing a detailed configuration of a fuel electrode 116. 5 is an explanatory diagram showing porosity at each position of a 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 identification method of thickness Tx of the 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 regarding the current collection member-single cell composite body 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 identification method of thickness Tx of the 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 a fuel cell stack 100 according to the first embodiment, and FIG. 2 is an explanatory diagram showing an XZ sectional configuration of the fuel cell stack 100 at a position II-II in FIG. 3 is an explanatory diagram showing a YZ sectional configuration of the fuel cell stack 100 at a position of III-III in FIG. In each drawing, XYZ axes that are orthogonal to each other for specifying directions are shown. In the present specification, for convenience, the Z-axis positive direction is referred to as the upward direction, and the Z-axis negative direction is referred to as the downward direction. However, the fuel cell stack 100 is actually different from such an orientation. It may be installed. The same applies to FIG. 4 and subsequent figures.

The fuel cell stack 100 includes a plurality of (seven in the present embodiment) fuel cell power generation units (hereinafter, simply referred to as “power generation units”) 102 and a pair of end plates 104 and 106. The seven power generation units 102 are arranged side by side in a predetermined array direction (up and down direction in this embodiment). The pair of end plates 104 and 106 are arranged so as to sandwich the assembly including the 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 this embodiment) holes penetrating in the up-down direction are formed at the peripheral edge around the Z direction of each layer (power generation unit 102, end plates 104, 106) forming the fuel cell stack 100. , The holes corresponding to each other formed in each layer communicate with each other in the vertical direction, and 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 hole formed in each layer of the fuel cell stack 100 to form the communication hole 108 may also be referred to as the communication hole 108.

A bolt 22 extending in the vertical direction is inserted into each communication hole 108, and the fuel cell stack 100 is fastened by the bolt 22 and the nuts 24 fitted on both sides of the bolt 22. As shown in FIGS. 2 and 3, between the nut 24 fitted on one side (upper side) of the bolt 22 and the upper surface of the end plate 104 that constitutes the upper end of the fuel cell stack 100, and between the bolts. An insulating sheet 26 is interposed between the nut 24 fitted to the other side (lower side) of 22 and the lower surface of the end plate 106 that constitutes the lower end of the fuel cell stack 100. However, at a place where a gas passage member 27 described later is provided, between the nut 24 and the surface of the end plate 106, the gas passage member 27 and the insulating sheets arranged on the upper side and the lower side of the gas passage member 27, respectively. 26 and 26 are interposed. The insulating sheet 26 is composed of, for example, a mica sheet, a ceramic fiber sheet, a ceramic powder sheet, a glass sheet, a glass ceramic composite 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 side on the X-axis positive direction side of the two sides parallel to the Y-axis) on the Z-direction outer periphery. The oxidant gas OG is introduced from the outside of the fuel cell stack 100 into the space formed by the bolt 22 (bolt 22A) and the communication hole 108 into which the bolt 22A is inserted, and the oxidant gas OG is used to generate electricity. A midpoint that functions as an oxidant gas introduction manifold 161 that is a gas flow path that supplies the unit 102 and is a side opposite to the side (side on the X-axis negative direction side of two sides parallel to the Y-axis). The space formed by the bolt 22 (bolt 22B) located in the vicinity and the communication hole 108 through which the bolt 22B is inserted, the oxidant off-gas OOG which is the gas discharged from the air chamber 166 of each power generation unit 102. It functions as an oxidant gas discharge manifold 162 that discharges the fuel cell stack 100 to the outside. In this embodiment, for example, air is used as the oxidant gas OG.

In addition, as shown in FIGS. 1 and 3, near the midpoint of one side (the Y-axis positive direction side of the two sides parallel to the X-axis) on the outer periphery of the fuel cell stack 100 around the Z-direction. The fuel gas FG is introduced from the outside of the fuel cell stack 100 into the space formed by the bolt 22 (bolt 22D) located at the position and the communication hole 108 into which the bolt 22D is inserted, and the fuel gas FG is used for power generation. A bolt 22 that functions as the fuel gas introduction manifold 171 that supplies the unit 102 and is located near the midpoint of the side opposite to the side (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, the fuel off gas FOG, which is the gas discharged from the fuel chamber 176 of each power generation unit 102, is discharged to the outside of the fuel cell stack 100. And functions as a fuel gas discharge manifold 172 for discharging the fuel gas. In this 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 portion 29 communicates with the hole of the main body portion 28. A gas pipe (not shown) is connected to the branch portion 29 of each gas passage member 27. Further, as shown in FIG. 2, the hole of the main body portion 28 of the gas passage member 27 arranged at the position of the bolt 22A 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 arranged at the position of the bolt 22B forming the oxidant gas discharge manifold 162 communicates with the oxidant gas discharge manifold 162. Further, as shown in FIG. 3, the hole of the 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. The hole of the main body portion 28 of the gas passage member 27 arranged at the position of the bolt 22E forming the discharge manifold 172 communicates with the fuel gas discharge manifold 172.

(Structure of end plates 104 and 106)
The pair of end plates 104 and 106 are substantially rectangular flat plate-shaped conductive members, and are made of, for example, stainless steel. One end plate 104 is arranged above the power generation unit 102 located at the top, and the other end plate 106 is arranged below the power generation unit 102 located at the bottom. A plurality of power generation units 102 are sandwiched by a pair of end plates 104 and 106 while being pressed. 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 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 an explanatory view showing a YZ section composition of two power generation units 102.

As shown in FIGS. 4 and 5, the power generation unit 102 includes a unit 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 forming 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 interconnector 150 have holes around the Z direction, which correspond to the communication holes 108 into which the bolts 22 are inserted.

The interconnector 150 is a substantially rectangular flat plate-shaped conductive member that is larger than the single cell 110 when viewed in the Z direction, and is made of, for example, ferritic stainless steel. The interconnector 150 secures electrical continuity between the power generation units 102 and prevents reaction gas from mixing between the power generation units 102. In this embodiment, when the two power generation units 102 are arranged adjacent to each other, one interconnector 150 is shared by the two adjacent power generation units 102. That is, the upper interconnector 150 in a certain power generation unit 102 is the same member as the lower interconnector 150 in another power generation unit 102 adjacent to the upper side of the power generation unit 102. Further, since the fuel cell stack 100 includes the pair of end plates 104 and 106, the power generation unit 102 located at the top of the fuel cell stack 100 does not include the upper interconnector 150, but 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 of the power generation units 102) with the electrolyte layer 112 interposed therebetween. The unit cell 110 of the present embodiment is a fuel electrode supporting type unit cell in which the fuel electrode 116 supports the electrolyte layer 112 and the air electrode 114.

The electrolyte layer 112 is a substantially rectangular plate-shaped member, and includes, for example, YSZ (yttria-stabilized zirconia), ScSZ (scandia-stabilized zirconia), SDC (samarium-doped ceria), GDC (gadolinium-doped ceria), and perovskite-type oxide. It is formed of a solid oxide such as. The air electrode 114 is a substantially rectangular flat plate-shaped member, and is formed of, for example, a perovskite type oxide (for example, LSCF (lanthanum strontium cobalt iron oxide), LSM (lanthanum strontium manganese oxide), LNF (lanthanum nickel iron)). Has been done. The fuel electrode 116 is a substantially rectangular flat plate-shaped member, and is formed of, for example, Ni (nickel), a cermet made of Ni and ceramic particles, a Ni-based alloy, or the like. The fuel electrode 116 corresponds to the specific electrode in the claims. The configuration of the fuel electrode 116 will be described in detail later. As described above, the unit 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-shaped member in which a substantially rectangular hole 121 penetrating in the vertical direction is formed near the center, and is formed of, for example, metal. The peripheral portion of the hole 121 in the separator 120 faces the peripheral portion of the surface of the electrolyte layer 112 on the air electrode 114 side. The separator 120 is joined to the electrolyte layer 112 (single cell 110) by a joining portion 124 formed of a brazing material (for example, Ag brazing material) arranged in the facing portion. The separator 120 separates an air chamber 166 facing the air electrode 114 and a fuel chamber 176 facing the fuel electrode 116, and gas leakage from one electrode side to the other electrode side in the peripheral portion of the unit cell 110 is prevented. Suppressed.

The air electrode side frame 130 is a frame-shaped 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 constitutes an air chamber 166 facing the air electrode 114. The air electrode side frame 130 is in contact with the peripheral edge of the surface of the separator 120 opposite to the side facing the electrolyte layer 112, and the peripheral edge of the surface of the interconnector 150 facing the air electrode 114. .. Further, the air electrode side frame 130 electrically insulates between the pair of interconnectors 150 included in the power generation unit 102. Further, in the air electrode side frame 130, an oxidant gas supply communication hole 132 that communicates the oxidant gas introduction manifold 161 and the air chamber 166, and an oxidant gas that communicates 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-shaped 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 constitutes a fuel chamber 176 facing the fuel electrode 116. The fuel electrode side frame 140 is in contact with the peripheral edge portion of the surface of the separator 120 facing the electrolyte layer 112 and the peripheral edge portion of the surface of the interconnector 150 facing the fuel electrode 116. Further, in the fuel electrode side frame 140, a fuel gas supply communication hole 142 that communicates the fuel gas introduction manifold 171 and the fuel chamber 176, and a fuel gas discharge communication hole 143 that communicates the fuel chamber 176 and the fuel gas discharge manifold 172. And are formed.

The fuel electrode side current collector 144 is arranged 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 connecting the electrode facing portion 145 and the interconnector facing portion 146. For example, nickel or a nickel alloy. , Stainless steel, etc. In the present embodiment, the fuel electrode side current collector 144 is made of Ni foil. A conductive bonding layer 310 is arranged on substantially the entire surface of the electrode facing portion 145 on the side 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 has a surface opposite to the side of the fuel electrode 116 facing the electrolyte layer 112 (that is, the side of the fuel electrode 116 facing the fuel electrode side current collector 144). And is in contact with a "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, the lowermost power generation unit 102 in the fuel cell stack 100 does not include the lower interconnector 150. Therefore, the interconnector facing portion 146 of the power generation unit 102 has a lower end plate. It is in contact with 106. 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. A spacer 149 made of mica, for example, is arranged 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. A good electrical connection with is maintained.

As shown in FIG. 4, in the present embodiment, the fuel electrode side current collector 144 is manufactured by making a cut in a rectangular flat plate-shaped member and processing it so as to bend and bend a plurality of rectangular portions. The bent rectangular portion serves as the electrode facing portion 145, the flat plate portion having a hole other than the bent portion serves as the interconnector facing portion 146, and the portion connecting the electrode facing portion 145 and the interconnector facing portion 146 is connected. It becomes part 147. Note that the partially enlarged view shown in FIG. 4 shows a state before the bending and bending of a part of the plurality of rectangular portions is completed in order to show the method for manufacturing the fuel electrode side current collector 144. Further, in the present embodiment, the electrode facing portion 145 and the bonding layer 310 are arranged in a substantially grid shape (on each intersection of the grid) when viewed in the Z direction. The area of each electrode facing portion 145 (that is, the area of the bonding layer 310) when viewed in the Z direction is, for example, 1 to 1000 (mm ² ).

In this specification, in each power generation unit 102, the assembly of the bonding layer 310, the fuel electrode side current collector 144, and the interconnector 150 located on the fuel electrode 116 side of the single cell 110 is referred to as the fuel electrode side current collector. It is called member 400. Since the fuel electrode side current collecting member 400 is configured as described above, a plurality of flat plate-shaped members (interconnectors 150) larger than the single cell 110 when viewed in the Z direction and a plurality of members contacting the current collecting member facing surface S1 of the fuel electrode 116 are provided. (A collection 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 protrusion 410 ”. ) And (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 protrusions 410 corresponds to the plurality of protrusions in the claims. In addition, in the present specification, a structure composed of the unit cell 110 and the fuel electrode side current collecting member 400 (fuel electrode side current collector 144, bonding layer 310, interconnector 150) is referred to as a current collecting member-fuel cell. A single cell composite (hereinafter, simply referred to as “current collecting member-single cell composite”) 107.

The air electrode side current collector 134 is arranged in the air chamber 166. The air electrode side current collector 134 is composed of a plurality of substantially square pole-shaped current collector elements 135, and is made of, for example, ferritic stainless steel. The air electrode side current collector 134 is in contact with the surface of the air electrode 114 opposite to the side facing the electrolyte layer 112 and the surface of the interconnector 150 facing the air electrode 114. However, as described above, since the uppermost power generation unit 102 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 is the upper end plate. It is in contact with 104. 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 this embodiment, the air electrode side current collector 134 and the interconnector 150 are formed as an integral member. That is, of the integrated member, a flat plate-shaped portion orthogonal to the vertical direction (Z-axis direction) functions as the interconnector 150, and is formed so as to project from the flat plate-shaped portion toward the air electrode 114. The current collector elements 135 that are a plurality of convex portions function as the air electrode side current collector 134. In addition, an integrated member of the air electrode side current collector 134 and the interconnector 150 may be covered with a conductive coat, and both of them may be provided between the air electrode 114 and the air electrode side current collector 134. A conductive bonding layer for bonding 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 a 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 a 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 is made from the fuel gas introduction manifold 171. It is supplied to the fuel chamber 176 through the hole 142.

When the oxidant gas OG is supplied to the air chamber 166 of each power generation unit 102 and the fuel gas FG is supplied to the fuel chamber 176, 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 with. This power generation reaction is an exothermic reaction. In each power generation unit 102, the air electrode 114 of the unit cell 110 is electrically connected to one interconnector 150 via the air electrode side current collector 134, and the fuel electrode 116 via the fuel electrode side current collector 144. It is electrically connected to the other interconnector 150. Further, the plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. Therefore, the electric energy generated in each power generation unit 102 is taken out from the end plates 104 and 106 that function as the output terminals of the fuel cell stack 100. Since the SOFC generates electric power at a relatively high temperature (for example, 700° C. to 1000° C.), the fuel cell stack 100 is heated by a heater ( It may be heated by (not shown).

The oxidant off-gas OOG exhausted from the air chamber 166 of each power generation unit 102 is exhausted to the oxidant gas exhaust manifold 162 via the oxidant gas exhaust communication hole 133 and further oxidized as shown in FIGS. 2 and 4. The fuel cell stack 100 passes 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, and through the gas pipe (not shown) connected to the branch portion 29. Is discharged to the outside. Further, the fuel off-gas FOG discharged from the fuel chamber 176 of each power generation unit 102 is discharged to the fuel gas discharge manifold 172 through the fuel gas discharge communication hole 143 as shown in FIGS. To the outside of the fuel cell stack 100 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 exhaust manifold 172 and the gas pipe (not shown) connected to the branch portion 29. Is 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 the configuration of the X1 portion of FIG. 4 in an enlarged manner. 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) near the fuel electrode side current collector 144 in the Z direction, and is a portion including 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 the surface of the fuel electrode 116 facing the electrolyte layer 112 (hereinafter, referred to as “electrolyte layer facing surface S2”). 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, the air electrode 114) forming the single cell 110, and diffuses the fuel gas FG supplied from the fuel chamber 176. In addition, it is a layer that functions as a field for collecting the electricity obtained by the power generation reaction. In addition, the active layer 210 is a layer that mainly functions as a place of reaction between oxide ions supplied from the electrolyte layer 112 and hydrogen contained in the fuel gas FG supplied from the fuel chamber 176 through the substrate layer 220. is there.

In the present embodiment, both the active layer 210 and the substrate layer 220 of the fuel electrode 116 are formed by cermet of Ni which is a conductive metal and YSZ particles which are oxide ion conductive ceramics. Further, in the present embodiment, in order to enhance the activity of the active layer 210, the Ni content rate (vol %) in the active layer 210 is higher than the Ni content rate in the substrate layer 220. Also, in order to increase the strength of the substrate layer 220, the thickness of the substrate layer 220 is thicker than the thickness of the active layer 210 in the Z direction. In addition, the porosity (vol %) of the substrate layer 220 is higher than that of the active layer 210 in order to enhance the gas diffusibility of the substrate layer 220.

Further, 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 a direction orthogonal to the Z direction (hereinafter, “plane direction”). When divided into a first portion PA1 and a second portion PA2 arranged in line), the porosity of the first portion PA1 is lower than the porosity of the second portion PA2. Here, the first portion PA1 is opposed to the tip surface (that is, the fuel electrode 116 of the bonding layer 310) of the current collecting member convex portion 410 (the assembly of the electrode facing portion 145 and the bonding layer 310) when viewed in the Z direction. This is a portion included in the convex portion overlapping region AR1 that overlaps with the surface on the side of performing the projection. Therefore, the first portion PA1 is a portion where the load from the fuel electrode side current collecting member 400 concentrates, and is a portion which is located in the main conduction path with the fuel electrode side current collecting member 400. Can be said. The second portion PA2 is a portion included in the convex portion non-overlapping area AR2 that does not overlap the tip end surface of the current collecting member convex portion 410 when viewed in the Z direction. As described above, in the present embodiment, in the specific region SA of the substrate layer 220, in the first portion PA1 that overlaps with the tip end surface of the current collecting member protrusion 410 when viewed in the Z direction, the current collecting member protrusion when viewed in the Z direction. The porosity is lower than that of the second portion PA2 that does not overlap the leading end surface of 410.

In the present embodiment, the first portion PA1 has a lower porosity than the second portion PA2, so that the content ratio of the conductive metal (Ni) and the oxide ion conductive ceramics (YSZ) particles is low. (Vol%) is high. In addition, 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 addition, in the present embodiment, the plurality of first portions PA1 and the plurality of second portions PA2 are present on the substrate layer 220, and each second portion PA2 corresponds to the two first portions PA1 in the plane direction. Located in 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) showing the porosity at each position on the virtual line L1 (see FIG. 6) that equally divides the convex overlap region AR1 in the plane direction in the cross section of the fuel electrode 116 is shown. Has been done. That is, the curve C(L1) shows the porosity at each position of the convex overlap region AR1 of the fuel electrode 116. As shown in FIG. 6, points P11 to 14 in the upper part of FIG. 7 are intersections between the virtual line L1 and the boundaries of the respective parts of the fuel electrode 116. Further, in the lower part of FIG. 7, in the cross section of the fuel electrode 116, a curve C (L2 indicating porosity at each position on a virtual line L2 (see FIG. 6) that equally divides the convex non-overlapping region AR2 in the plane direction. )It is shown. That is, the curve C(L2) shows the porosity at each position of the convex non-overlapping region AR2 of the fuel electrode 116. Note that, as shown in FIG. 6, points P21 to P24 in the lower part of FIG. 7 are intersections of the virtual line L2 and the boundary of each part of the fuel electrode 116.

As shown in the lower part of FIG. 7, in the convex 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. The porosity of the active layer 210 is also substantially constant. As described above, the porosity of the active layer 210 is lower than that of the substrate layer 220.

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

Further, 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 (the convex overlapping region AR1 thereof) is 50% or less. Therefore, the proportion of the first portion PA1 in the entire fuel electrode 116 is relatively small.

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

(Preparation of green sheet for fuel electrode substrate layer)
Organic beads (15% by weight with respect to the mixed powder), which are pore-forming materials, and butyral resin, for a mixed powder (100 parts by weight) of NiO powder (50 parts by weight) and YSZ powder (50 parts by weight). Then, DOP which is a plasticizer, a dispersant, and a mixed solvent of toluene and ethanol 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 polymethylmethacrylate or polystyrene. The obtained slurry is thinned by a doctor blade method to produce a plurality of fuel electrode substrate layer green sheets having a predetermined thickness. The ratio of the NiO powder to the YSZ powder in the green sheet for the fuel electrode substrate layer can be changed as appropriate as long as the performance is satisfied. For example, even if NiO powder:YSZ powder is 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 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 by spraying or printing to the region corresponding to the first portion PA1 described above. After coating the low-viscosity NiO, the target green sheet for the fuel electrode substrate layer is impregnated with NiO by leaving it for a predetermined time. As a result, the content 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 can be increased. The porosity of the can be reduced.

(Preparation of green sheet for fuel electrode active layer)
To 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, a dispersant, and a toluene+ethanol mixed solvent were added. In addition, they are mixed in a ball mill to prepare a slurry. The obtained slurry is thinned by a doctor blade method to prepare a green sheet for a fuel electrode active layer having a predetermined thickness (for example, 10 μm to 30 μm). The ratio between the NiO powder and the YSZ powder in 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 ratio of 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 the YSZ powder.

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

(Preparation of Laminated Body of Electrolyte Layer 112 and 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. Further, by firing at about 1350° C., a laminated body of the electrolyte layer 112 and the fuel electrode 116 (active layer 210 and substrate layer 220) is obtained. The first layer PA1 and the second portion PA2 having the above-described configuration are formed on the substrate layer 220 of the fuel electrode 116 in the produced stack.

(Formation of air electrode 114)
A mixed solution of La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ powder and isopropyl alcohol is prepared. The prepared mixed liquid is spray-coated on the surface of the electrolyte layer 112 in the above-mentioned laminated body, and baked at 1100° C. to form the air electrode 114. Through the above steps, the unit cell 110 is manufactured.

After that, the remaining assembly process (for example, joining of the fuel electrode side current collector 144 and the unit cell 110 (fuel electrode 116) or fastening with the bolt 22) is performed. For example, at the time of joining the fuel electrode side current collector 144 and the unit cell 110 (fuel electrode 116), of the surface of the fuel electrode 116 on the substrate layer 220 side (collector facing surface S1) of the unit cell 110. , The area for facing the electrode facing portion 145 of the fuel electrode side current collector 144 (that is, the surface of the first portion PA1) is printed with the bonding layer paste, and the electrode facing portion 145 is pressed against the paste. By firing under the conditions described above, the bonding layer 310 that bonds 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 composite body 107 of the present embodiment is arranged on the single cell 110 and the fuel electrode 116 side of the single cell 110, and a 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 the fuel electrode side current collector 144, bonding layer 310) is provided. .. Further, in the current collecting member-single cell composite body 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 convex portion overlapping region AR1 that overlaps with the current collecting member convex 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 which is located in the main conduction path with 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 the current collecting member convex portion 410 when viewed in the Z direction. In the current collecting member-single cell composite body 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 composite body 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 concentrates on each convex portion overlapping region AR1 of the fuel electrode 116. However, in the current collecting member-single cell composite body 107 of the present embodiment, the porosity of the first portion PA1 which is a part of the convex overlapping region AR1 in which the load from the fuel electrode side current collecting member 400 acts intensively. Is low, it is possible to increase the strength of the first portion PA1, and it is possible to suppress the occurrence of cracks in the unit cell 110 due to the concentration of load from the fuel electrode side current collecting member 400.

Note that, for example, by reducing the porosity of the entire specific region SA in the fuel electrode 116, it is possible to suppress the occurrence of cracks in the single cell 110. However, with such a configuration, the diffusibility of the fuel gas FG is reduced 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 composite body 107 of the present embodiment, of the specific region SA of the fuel electrode 116, only the first portion PA1 overlapping the current collecting member convex portion 410 when viewed in the Z direction has a porosity. Is low, and the porosity of the second portion PA2, which does not overlap the current collecting member convex portion 410 when viewed in the Z direction, is maintained in a high porosity state. Therefore, in the current collecting member-single cell composite body 107 of the present embodiment, it is possible to suppress the occurrence of cracks in 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 composite body 107 of the present embodiment, the fuel electrode 116 contains a conductive metal (Ni), and the conductive metal content rate (vol%) of the first portion PA1 is the second. Is higher than the conductive metal content of the portion PA2. Therefore, according to the current collecting member-single cell composite body 107 of the present embodiment, in the fuel electrode 116, the conductive metal of the first portion PA1 located in the main conduction path with the fuel electrode side current collecting member 400. Can be increased, and the conductivity of the single cell 110 can be improved.

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

Further, in the current collecting member-single cell composite body 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 convex overlapping region AR1 thereof). Is 50% or less. Therefore, according to the current collecting member-single cell composite body 107 of the present embodiment, cracking of the single cell 110 occurs while suppressing a decrease in gas diffusivity by keeping the porosity of the fuel electrode 116 as a whole high to some extent. Can be suppressed.

Further, in the current collecting member-single cell composite body 107 of the present embodiment, the fuel electrode 116 has a plurality of first portions PA1 overlapping 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 composite body 107 of the present embodiment, a plurality of first portions PA1 having high strength are provided side by side in the plane direction while suppressing a decrease in gas diffusibility of the fuel electrode 116 as a whole. As a result, the occurrence of cracks in the unit cell 110 can be suppressed even more effectively.

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

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

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

Note that, as shown in FIG. 6, in the cross section of the fuel electrode 116, the thickness Tw (for example, 10 μm) that overlaps with the tip end surface of the current collecting member convex portion 410 in the Z direction (that is, is located in the convex portion overlapping region AR1). ) Of the first window W1 does not overlap with the tip surface of the current collecting member convex portion 410 when viewed in the Z direction (that is, is located in the convex portion non-overlapping area AR2), and is adjacent to the first window W1 in the plane direction. The pair with the second window W2 having the thickness Tw positioned is sequentially set while being shifted 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. And the porosity of the area to be filled. In a pair of a first window W1 and a second window W2, if the porosity of the area defined by the first window W1 is lower than the porosity of the area defined by the second window W2, the first window W1 The area defined by W1 corresponds to the first portion PA1, and the area defined by the second window W2 corresponds to the second portion PA2.

(Method of specifying the thickness Tx of the first portion 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) showing the porosity at each position on the imaginary line L1 is substantially linear from the intersection P11 with the current collector facing surface S1 toward the Z axis positive direction. , The porosity decreases in the vicinity of the boundary between the other portion and the first portion PA1 and then becomes substantially linear again in the first portion PA1. An imaginary line Lm that is equidistant from the two substantially linear portions of the curve C(L1) is identified, an intersection of the imaginary line Lm and the curve C(L1) is identified, and the position of the intersection (point P12). 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. In the following, of the configurations of the fuel electrode 116a (single cell 110a) in the second embodiment, the same configurations as the configurations of the fuel electrode 116 (single cell 110) in the above-described first embodiment are denoted by the same reference numerals. Therefore, the description thereof will be appropriately omitted.

As shown in FIG. 8, in the second embodiment, the position of the specific area 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 collector member facing surface S1 of the substrate layer 220. Also in the second embodiment, the first portion PA1 of the specific region SA that overlaps the tip surface of the current collecting member convex portion 410 when viewed in the Z direction overlaps the tip surface of the current collecting member convex portion 410 when viewed in the Z direction. The porosity is low, the content of the conductive metal is high, and the content of the oxide ion conductive ceramic particles is high as compared with the second portion PA2 that does not become.

In the current collecting member-single cell composite body 107 including the single cell 110a and the fuel electrode side current collecting member 400 of the second embodiment, like the current collecting member-single cell composite body 107 of the first embodiment described above, Since the porosity of the first portion PA1 that is a portion where the load from the fuel electrode side current collecting member 400 acts intensively is low, the strength of the first portion PA1 can be increased, and the fuel electrode side current collecting member can be increased. It is possible to suppress the occurrence of cracks in the unit cell 110a due to load concentration from 400. Further, in the current collecting member-single cell composite body 107 of the second embodiment, the porosity of only the first portion PA1 of the specific region SA of the fuel electrode 116a overlapping the current collecting member convex portion 410 when viewed in the Z direction has a porosity. Since the second portion PA2, which is made low and does not overlap the current collecting member convex portion 410 when viewed in the Z direction, has a high porosity, the diffusion of the fuel gas FG at the fuel electrode 116a is reduced. Can be suppressed.

In the current collecting member-single cell composite body 107 of the second embodiment, the conductive metal content of the first portion PA1 is the same as that of the first embodiment described above, and the conductive metal of the second portion PA2 is the same. Therefore, 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 in the fuel electrode 116a can be increased, and the unit cell can be increased. The conductivity of 110a can be improved.

Further, in the current collecting member-single cell composite body 107 of the second embodiment, the content of the oxide ion conductive ceramics particles in the first portion PA1 is the second portion PA2 as in the first embodiment described above. Since it is higher than the content rate of the oxide ion conductive ceramic particles of No. 1, it is possible to effectively improve 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. Therefore, it is possible to effectively prevent the single cell 110a from being cracked due to the concentration of the load from the fuel electrode side current collecting member 400.

Further, in the current collecting member-single cell composite body 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 is the same as in the first embodiment described above. Since the ratio of Tx is 50% or less, it is possible to suppress the occurrence of cracks in the unit cell 110a while keeping the porosity of the fuel electrode 116a high as a whole to suppress the decrease in gas diffusibility. You can

Further, in the current collecting member-single cell composite body 107 of the second embodiment, as in the above-described first embodiment, the fuel electrode 116a has a plurality of overlapping current collecting member convex portions 410 when viewed in the Z direction. Since the first portion PA1 is provided, a plurality of the first portions PA1 having high strength are arranged side by side in the plane direction while suppressing the deterioration of the gas diffusibility of the fuel electrode 116a as a whole, and thus the unit cell 110a is cracked. Can be suppressed more effectively.

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 of identifying the thickness Tx of the first portion PA1 in the second embodiment. In the cross section of the fuel electrode 116a of the second embodiment, FIG. 9 shows a curve C(L1) showing the porosity at each position on a virtual line L1 (see FIG. 8) that equally divides the convex overlap region AR1 in the plane direction. )It is shown. As shown in FIG. 9, in the second embodiment, the curve C(L1) is substantially linear in the first portion PA1 arranged on the current collecting member facing surface S1 side, and the curve C(L1) is different from the first portion PA1. The porosity increases near the boundary with the part, and then becomes linear again in other parts. An imaginary line Lm that is equidistant from the two substantially linear portions of the curve C(L1) is identified, an intersection of the imaginary line Lm and the curve C(L1) is identified, and a current collecting member is located from the position of the intersection. 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. In the following, of the configurations of the fuel electrode 116b (single cell 110b) in the third embodiment, the same configurations as the configurations of the fuel electrode 116 (single cell 110) in the first embodiment described above will be denoted by the same reference numerals. Therefore, the description thereof will be appropriately omitted.

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

In the current collecting member-single cell composite body 107 including the single cell 110b and the fuel electrode side current collecting member 400 of the third embodiment, like the current collecting member-single cell composite body 107 of the first embodiment described above, Since the porosity of the first portion PA1 that is a portion where the load from the fuel electrode side current collecting member 400 acts intensively is low, the strength of the first portion PA1 can be increased, and the fuel electrode side current collecting member can be increased. It is possible to suppress cracking of the single cell 110b due to load concentration from 400. In particular, in the current collecting member-single cell composite body 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 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 composite body 107 of the third embodiment, the porosity of only the first portion PA1 of the specific region SA of the fuel electrode 116b overlapping the current collecting member convex portion 410 when viewed in the Z direction has a porosity. Since the second portion PA2, which is made low and does not overlap the current collecting member convex portion 410 when viewed in the Z direction, has a high porosity, the diffusion of the fuel gas FG at the fuel electrode 116b is reduced. Can be suppressed.

Further, in the current collecting member-single cell composite body 107 of the third embodiment, the conductive metal content of the first portion PA1 is the same as that of the first embodiment described above, and the conductive metal of the second portion PA2 is the same. Therefore, 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 in the fuel electrode 116b can be increased, and the unit cell can be increased. The conductivity of 110b can be improved. In particular, in the current collecting member-single cell composite body 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 made of conductive metal. Since it is the first portion PA1 having a high content rate of, the conductivity of the single cell 110b can be effectively improved.

Further, in the current collecting member-single cell composite body 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. Since it is higher than the content rate of the oxide ion conductive ceramic particles of No. 1, it is possible to effectively improve 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. Therefore, it is possible to effectively prevent the single cell 110b from being cracked due to the concentration of the load from the fuel electrode side current collecting member 400. In particular, in the current collecting member-single cell composite body 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 the first portion PA1 has a high content rate of the conductive ceramic particles, it is possible to effectively suppress the occurrence of cracks in the single cell 110b.

Further, in the current collecting member-single cell composite body 107 of the third embodiment, similar to the above-described first embodiment, the fuel electrode 116b 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, cracking of the unit cell 110b is caused by arranging a plurality of first portions PA1 having high strength in the plane direction while suppressing a decrease in gas diffusibility of the fuel electrode 116b as a whole. Can be suppressed more effectively.

D. Fourth Embodiment:
FIG. 11 is an explanatory diagram showing a detailed configuration of the fuel electrode 116c in the fourth embodiment. In the following, of the configurations of the fuel electrode 116c (single cell 110c) in the fourth embodiment, the same configurations as the configurations of the fuel electrode 116 (single cell 110) in the above-described first embodiment are denoted by the same reference numerals. Therefore, the description thereof will be appropriately omitted.

As shown in FIG. 11, the fourth embodiment is different from the first embodiment described above in that two specific regions SA are present in the fuel electrode 116c. Specifically, in the fourth embodiment, in the fuel electrode 116c, the 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 the substrate layer 220 in the substrate layer 220. There is a second specific area SA2 that is an area having a thickness Tx(2) from the current collector facing surface S1. Also in the fourth embodiment, the first portion PA1 of each specific area SA that overlaps the tip surface of the current collecting member convex portion 410 when viewed in the Z direction is the same as the tip 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 the conductive metal is high, and the content of the oxide ion conductive ceramic particles is high.

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

In the current collecting member-single cell composite body 107 including the single cell 110c and the fuel electrode side current collecting member 400 of the fourth embodiment, like the current collecting member-single cell composite body 107 of the first embodiment described above, Since the porosity of the first portion PA1 that is a portion where the load from the fuel electrode side current collecting member 400 acts intensively is low, the strength of the first portion PA1 can be increased, and the fuel electrode side current collecting member can be increased. It is possible to suppress the occurrence of cracks in the unit cell 110c due to load concentration from 400. In particular, in the current collecting member-single cell composite body 107 of the fourth embodiment, since the two first portions PA1 having a low porosity are present in each convex overlap region AR1, the single cell 110c is cracked. This can be effectively suppressed. Further, in the current collecting member-single cell composite body 107 of the fourth embodiment, the porosity of only the first portion PA1 of the specific region SA of the fuel electrode 116c overlapping the current collecting member convex portion 410 when viewed in the Z direction has a porosity. Since the second portion PA2, which is made low and does not overlap the current collecting member convex portion 410 when viewed in the Z direction, has a high porosity, the diffusion of the fuel gas FG at the fuel electrode 116c is reduced. Can be suppressed.

Further, in the current collecting member-single cell composite body 107 of the fourth embodiment, the conductive metal content rate (vol %) of the first portion PA1 is the second portion PA2 as in the above-described first embodiment. Therefore, 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 can be increased in the fuel electrode 116c. Therefore, the conductivity of the single cell 110c can be improved. In particular, in the current collecting member-single cell composite body 107 of the fourth embodiment, two first portions PA1 having a high content ratio of the conductive metal are present in each convex portion overlapping region AR1, so that the single cell 110c has the same structure. The conductivity can be effectively improved.

Further, in the current collecting member-single cell composite body 107 of the fourth embodiment, the content (vol%) of the oxide ion conductive ceramics particles in the first portion PA1 is the same as that of the first embodiment described above. Since the content of the oxide ion conductive ceramics particles in the second portion PA2 is higher than that in the second portion PA2, 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 cracking due to the load concentration from the fuel electrode side current collecting member 400. Particularly, in the current collecting member-single cell composite body 107 of the fourth embodiment, two first portions PA1 having a high content rate of the oxide ion conductive ceramics particles are present in each convex portion overlapping region AR1, It is possible to effectively suppress the occurrence of cracks in the unit cell 110c.

Further, in the current collecting member-single cell composite body 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 the first embodiment described above. Since the ratio of the total of Tx is 50% or less, by maintaining the porosity of the fuel electrode 116c as a whole high to some extent, it is possible to suppress the deterioration of the gas diffusibility and suppress the occurrence of cracks in the single cell 110c. can do.

Further, in the current collecting member-single cell composite body 107 of the fourth embodiment, similar to the above-described first embodiment, the fuel electrode 116c has a plurality of overlapping current collecting member convex portions 410 when viewed in the Z direction. Since the first portion PA1 is provided, a plurality of the first portions PA1 having high strength are arranged side by side in the plane direction while suppressing the deterioration of the gas diffusibility of the fuel electrode 116c as a whole, whereby the unit cell 110c is cracked. Can be suppressed more effectively.

E. Example:
FIG. 12 is an explanatory diagram showing the configuration of an example of the current collecting member-single cell composite body 107 of each of the embodiments described above. In FIG. 12, for each of Examples 1 to 3, the content of the conductive metal (Ni) in the first portion PA1 and the second portion PA2, the content of the oxide ion conductive ceramics (YSZ) particles, 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. 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 the first embodiment, it is possible to suppress the occurrence of cracks in the unit cell 110 while suppressing the decrease in the diffusibility of the fuel gas FG at the fuel electrode 116, and to improve the conductivity of the unit cell 110. be able to.

In Example 2, the first portion PA1 has a lower porosity, a higher content ratio of the conductive metal, and a higher content ratio of the oxide ion conductive ceramic particles, as compared with the second part PA2. Therefore, in the second embodiment, it is possible to effectively suppress the occurrence of cracks in the single cell 110 while suppressing the decrease in the diffusibility of the fuel gas FG at the fuel electrode 116, and also to improve the conductivity of the single cell 110. Can be improved.

F. Modification:
The technology disclosed in the present specification is not limited to the above-described embodiment, and can be modified into various forms without departing from the gist thereof, for example, the following modifications are also possible.

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

Further, in the above-described embodiment, the position of the specific area SA on the fuel electrode 116 is merely an example, and can be variously modified. 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, and in the second embodiment, the specific area SA is in the substrate layer 220. Although it is described as a region having a thickness Tx from the current collecting member facing surface S1, as shown in FIG. 13, the specific region SA is also seen 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 modified example shown in FIG. 13 is specified by the following method. FIG. 14 is an explanatory diagram showing a method of identifying the thickness Tx of the first portion PA1 in the modification shown in FIG. FIG. 14 is a curve C showing the porosity at each position on the virtual line L1 (see FIG. 13) that equally divides 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 collector member facing surface S1 in the positive Z-axis direction, and the porosity is near the boundary between the other portion and the first portion PA1. After that, it becomes substantially straight again in the first portion PA1. An imaginary line Lm1 that is equidistant from these two substantially linear portions of the curve C(L1) is specified, and the intersection of the imaginary line Lm1 and the curve C(L1) (in the case where there are a plurality of intersections, the current collector member faces each other). 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 portion PA1 on the current collector facing surface S1 side. Further, as shown in FIG. 14, the curve C(L1) is located in the vicinity of the boundary between the first portion PA1 and the other portion in the Z-axis positive direction from the substantially linear portion of the first portion PA1. The porosity increases, and it becomes linear again in other parts. An imaginary line Lm2 that is equidistant from these two substantially linear portions of the curve C(L1) is specified, and the intersection of the imaginary line Lm2 and the curve C(L1) (if there are a plurality of intersections, the interface BO is most A close intersection (excluding the intersection on the interface BO) is specified, and the position of the intersection is set as the 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.

Further, in the above embodiment, the bonding layer 310 is provided between the electrode facing portion 145 of the fuel electrode side current collector 144 and the current collector facing surface S1 of the fuel electrode 116, but the bonding layer 310 is provided. Alternatively, 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 of the first portion PA1 of the fuel electrode 116 is made lower than the porosity of the second portion PA2, the occurrence of cracks in the unit cell 110 can be suppressed.

Further, the configuration of the fuel electrode side current collector 144 in the above embodiment is merely an example, and can be variously modified. 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-shaped portion (interconnector 150) orthogonal to the Z direction. And a plurality of convex portions (air electrode side current collector 134) formed so as to project from the flat plate-shaped portion toward the fuel electrode 116. Further, in such a configuration, the surface of the flat plate-shaped portion on the side opposite to the side on which the plurality of convex portions are formed may not be a flat surface, but may be a surface having irregularities.

Further, in the above embodiment, regarding 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, it does not necessarily have to be such a configuration. For at least one first portion PA1 of the fuel electrode 116, the porosity of the first portion PA1 may be lower than the porosity of the second portion PA2 adjacent to the first portion PA1. With such a configuration, it is possible to suppress the occurrence of cracks in the unit cell 110 near the position of the first portion PA1. In order to effectively suppress the occurrence of cracks in the unit cell 110, the porosity of the first portion PA1 is 50% or more of all the first portions PA1 of the fuel electrode 116, and It is preferable that the porosity is lower than that of the second portion PA2 adjacent to the portion PA1. When the number of the first parts PA1 in the fuel electrode 116 is 20 or less, the porosity of all the first parts PA1 is specified by the specifying method. Further, when the number of the first portions PA1 in the fuel electrode 116 exceeds 20, the porosity of any 20 first portions PA1 is specified by the specifying method described above, and the specified porosity is obtained. Based on this, the configuration of the other first portion PA1 is estimated.

In addition, in each of the above-described embodiments, the content rate (vol%) of the conductive metal in the first portion PA1 is higher than the content rate (vol%) of the conductive metal in the second portion PA2. It is not necessary to have such a relationship, and for example, the conductive metal content of the first portion PA1 may be equal to the conductive metal content of the second portion PA2. Further, in the above-described embodiment, the content rate (vol%) of the oxide ion conductive ceramics particles in the first portion PA1 is smaller than the content rate (vol%) of the oxide ion conductive ceramics particles in the second portion PA2. Although it is supposed to be high, it is not always necessary to have such a relationship. For example, the content of the oxide ion conductive ceramics particles in the first portion PA1 is the content of the oxide ion conductive ceramics 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 above-described fuel electrode 116. That is, the air electrode 114 is a first portion that is at least a part of a region (projection overlapping region) that overlaps with the air electrode side current collector 134 when viewed in the Z direction, and is adjacent to the first portion in the plane direction. It may be configured to have a first portion that is located and has a lower porosity than the second portion that is a portion that does not overlap the air electrode side current collector 134 when viewed in the Z direction. By doing so, it is possible to suppress the occurrence of cracks in the single cell 110 while suppressing the decrease in the diffusibility of the oxidant gas OG in the air electrode 114, and to improve the conductivity of the single cell 110. be able to.

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

In addition, the material forming each member in the above embodiment is merely an example, and each member may be formed of another material. For example, in the above embodiment, the fuel electrode 116 is formed by cermet of Ni which is a conductive metal and particles of YSZ which is an oxide ion conductive ceramics. However, as the conductive metal, a metal other than Ni is used. (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 ceramics.

In the present specification, the fact that the member B and the member C face each other with the member (or a portion having the member, the same applies hereinafter) sandwiched therebetween 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 the member A and the member B or the 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 in between.

Further, the method of manufacturing the fuel cell stack 100 in the above embodiment is merely an example, and can be variously modified. For example, in the above-described embodiment, the low-viscosity NiO is applied to the surface of the specific green sheet for the fuel electrode substrate layer 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 on the fuel electrode 116, it is not always necessary to apply the conductive metal or its oxide (for example, NiO), and such a structure may be formed by another method. The single cell 110 may be manufactured.

Further, in the above-described embodiment, the SOFC that generates electric power by utilizing the electrochemical reaction between hydrogen contained in the fuel gas and oxygen contained in the oxidant gas is targeted, but the present invention is directed to the electrolysis reaction of water. It is similarly applicable to an electrolytic single cell that is a constituent unit of a solid oxide electrolytic cell (SOEC) that uses hydrogen to generate hydrogen, and an electrolytic cell stack including a plurality of electrolytic single cells. The configuration of the electrolysis cell stack is publicly known as described in, for example, Japanese Patent Application Laid-Open No. 2014-207120, and therefore will not be described in detail here. It is a composition. 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 as an electrolytic cell unit, and the single cell 110 as an electrolytic single cell. However, during the operation of the electrolysis cell stack, a voltage is applied between both electrodes so that the air electrode 114 becomes positive (anode) and the fuel electrode 116 becomes negative (cathode), and at the same time through the communication hole 108. Steam as a raw material gas is supplied. As a result, an electrolysis reaction of water occurs in each electrolytic cell unit, hydrogen gas is generated in the fuel chamber 176, and hydrogen is taken out of the electrolytic cell stack through the communication hole 108.

Further, although the solid oxide fuel cell (SOFC) has been described as an example in the above embodiment, the present invention may be applied to other types of fuel cells (or electrolytic cells) such as a molten carbonate fuel cell (MCFC). Applicable.

22: Bolts 24: Nuts 26: Insulation sheet 27: Gas passage member 28: Main body part 29: Branch part 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: Joint part 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 part 146: Interconnector facing part 147: Connecting part 149: Spacer 150: Interconnector 161: Oxidizing gas introduction manifold 162: Oxidizing gas discharge manifold 166: Air chamber 171: Fuel gas introduction manifold 172: Fuel gas exhaust 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 (6)

An electrochemical reaction single cell including an electrolyte layer and an air electrode and a fuel electrode facing each other in the first direction with the electrolyte layer interposed therebetween, and at least one of the air electrode and the fuel electrode of the electrochemical reaction single cell. Is disposed on the specific electrode side, which is a current collector having a plurality of convex portions in contact with the surface of the specific electrode, and a current collector-electrochemical reaction single cell composite,
The specific electrode is a first portion that is at least a part of a convex portion overlapping region that overlaps the convex portion when viewed in the first direction, and is the first portion in a second direction orthogonal to the first direction. have a first second of the first portion porosity is less than the portion is a portion which does not overlap with the protrusion in the direction viewed along with located next to the part,
The specific electrode has a plurality of the first portions that overlap with each of the plurality of convex portions in the first direction, and the current collecting member-electrochemical reaction single cell composite body. The current collecting member-electrochemical reaction single cell composite according to claim 1,
The specific electrode includes a conductive metal,
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. The current collecting member-electrochemical reaction single cell complex according to claim 1 or 2,
The specific electrode includes oxide ion conductive ceramic particles,
The content rate (vol%) of the oxide ion conductive ceramics particles in the first portion is higher than the content rate (vol%) of the oxide ion conductive ceramics particles in the second portion. A current collecting member-electrochemical reaction single cell composite. The current collecting member-electrochemical reaction single cell complex according to any one of claims 1 to 3,
The first portion is a whole portion 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. The current collecting member-electrochemical reaction single cell composite body according to any one of claims 1 to 3,
In the first direction, a ratio of a thickness of a region occupied by the first portion in the convex overlapping region to a thickness of the convex overlapping region is 50% or less. Current collector-electrochemical reaction single cell composite. 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 member-electrochemical reaction single cell complexes is the current collecting member-electrochemical reaction single cell complex according to any one of claims 1 to 5. An electrochemical reaction cell stack characterized by.

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