JP6878257B2 - Current collector-electrochemical reaction single cell complex and electrochemical reaction cell stack - Google Patents

Description

The techniques disclosed herein relate to current collector-electrochemical reaction single cell complexes.

As one of the types of fuel cells that generate electricity by utilizing the electrochemical reaction of hydrogen and oxygen, a solid oxide fuel cell (hereinafter, also referred to as "SOFC") having an electrolyte layer containing a solid oxide is used. Are known. The current collector-fuel cell single cell composite (hereinafter, simply referred to as “composite”) constituting the SOFC includes, for example, an electrolyte layer and an air electrode and a fuel electrode facing each other in the first direction with the electrolyte layer in between. A single cell including the above, and a conductive current collecting member arranged on the air electrode side of the single cell for collecting the electric power generated by the single cell. Generally, the current collecting member arranged on the air electrode side of the single cell has a protruding portion protruding toward the air electrode. By joining the air electrode and the protruding portion of the current collecting member by a conductive joint portion, the air electrode and the current collecting member are electrically connected.

Conventionally, in a cross section parallel to the first direction including a protrusion, a joint, and an air electrode, the outlines of two end portions located on both sides of the second direction orthogonal to the first direction at the joint are formed. , A configuration is known which is an inclined straight line extending linearly so as to be separated from each other as it approaches the air electrode (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-339904

In the configuration in which the outer line of the end portion of the joint portion is an inclined straight line as described above, the performance of the complex may be deteriorated. The possible causes for this are as follows. That is, in order to improve the performance of the complex, it is preferable that the oxidizing agent gas from the air chamber is sufficiently diffused in the central portion of the joint portion located between the protruding portion and the air electrode. However, in the configuration in which the outer line of the end portion of the joint portion is an inclined straight line as described above, the exposed surface of the joint portion exposed to the air chamber facing the air electrode due to the presence of the end portion whose outer line is an inclined straight line. The distance between the joint and the central part of the joint is long. Therefore, it is considered that the performance of the complex deteriorates due to insufficient diffusion of the oxidant gas from the air chamber into the central portion of the joint.

It should be noted that such a problem is also a common problem in the configuration in which the protruding portion of the current collector member arranged on the fuel electrode side of the single cell and the fuel electrode are joined by a conductive joint portion. Further, such a problem is caused by a current collecting member-electrolytic cell complex constituting a solid oxide fuel cell (hereinafter, also referred to as “SOEC”) that generates hydrogen by utilizing an electrolysis reaction of water. Is also a common issue. In this specification, the current collector-fuel cell single cell complex and the current collector-electrolytic cell complex are collectively referred to as a current collector-electrochemical reaction single cell complex.

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

The techniques disclosed herein can be realized, for example, in the following forms.

(1) The current collector-electrochemical reaction single cell composite disclosed in the present specification includes an electrolyte layer containing a solid oxide, an air electrode and a fuel that face each other in a first direction with the electrolyte layer interposed therebetween. A single cell including a pole, and a protruding portion arranged on one electrode side of the air electrode and the fuel electrode of the single cell, projecting toward the one electrode and separated from the one electrode. In a current collecting member-electrochemical reaction single cell composite comprising a current collecting member having a current collecting member and a joint portion in which the protruding portion and one of the electrodes are joined to have conductivity and pores are present, the protruding portion is provided. In at least one cross section parallel to the first direction, including the portion, the junction, and the one electrode, the junction comprises a central portion located between the protrusion and the one electrode. An end portion located on at least one side of the second direction orthogonal to the first direction with respect to the central portion is included, and the outline of the end portion becomes closer to the one electrode. It includes a curved line curved toward the central portion so as to be separated from the central portion, passes through a portion closest to the one electrode at the boundary between the protruding portion and the end portion of the joint portion, and is said to be described. The position on the outer line of the end portion intersecting with the first virtual straight line parallel to the second direction is set as the first position, and among the portions of the end portion having the thinnest thickness in the first direction. The position on the outer line at the portion closest to the central portion is set as the second position, the second virtual straight line passing through the first position and parallel to the first direction, and the second When the position where the third virtual straight line passing through the position and intersecting the third virtual straight line parallel to the second direction intersects with the third position, the first position, the second position, and the third position are defined as the third position. The ratio of the area of the specific region surrounded by the fourth virtual straight line connecting the first position and the second position and the curved line is 20% with respect to the area of the virtual triangle whose apex is the position of. That is all. In this current collector-electrochemical reaction single cell complex, the outline of the end portion of the joint includes a curved line curved toward the center portion so as to move away from the central portion of the joint as it approaches one of the electrodes. I'm out. Further, the ratio of the area of the specific region formed by the curved line to the area of the virtual triangle including the curved line is 20% or more. Therefore, for example, as compared with the case where the outer line of the end portion of the joint portion is linear, the area of the exposed surface of the joint portion exposed to the gas chamber facing the electrode becomes larger and the exposed surface and the exposed surface are exposed. The separation distance from the central part of the joint is shortened. As a result, according to the current collector-electrochemical reaction single cell composite, the current collector-electrochemical reaction single cell is caused by the fact that the gas from the gas chamber is not sufficiently diffused to the central portion at the joint. It is possible to suppress the deterioration of the performance of the complex.

(2) In the current collector-electrochemical reaction single cell complex, the first distance between the first position and the third position in the at least one cross section is the second position. It may be configured to be longer than the second distance between the third position and the third position. In this current collector-electrochemical reaction single cell complex, the first distance between the first position and the third position is the second distance between the second position and the third position. Longer. As a result, the gas from the gas chamber is diffused to the central portion by making the entire exposed surface of the end portion of the joint portion closer to the central portion of the joint portion as compared with the configuration in which the first distance is shorter than the second distance. It is possible to more effectively suppress the deterioration of the performance of the current collector-electrochemical reaction single cell composite due to insufficient diffusion of gas.

(3) In the current collector-electrochemical reaction single cell complex, in at least one cross section, the one electrode may be configured to be the air electrode. In the present current collector-electrochemical reaction single cell composite, the present invention is applied to a joint portion for joining a protruding portion and an air electrode of a current collector member arranged on the air electrode side. As a result, the gas from the gas chamber is not sufficiently diffused to the central portion of the junction where the current density is particularly high and many electrons are present in the junction, so that the current collector-electrochemical reaction single cell composite is formed. It is possible to effectively suppress the deterioration of performance.

(4) In the current collector-electrochemical reaction single cell composite, the current collector has a plurality of the protrusions, and each of the two protrusions adjacent to each other in the at least one cross section. The end portions of the joint portions that join the one electrode and the one electrode may be connected to each other. In this current collector-electrochemical reaction single cell complex, the end portions of the joints that join each of the two adjacent protrusions and the electrodes are connected to each other. As a result, peeling between the joint portion and the electrode can be suppressed as compared with the configuration in which the end portions of the joint portions adjacent to each other are separated from each other.

The technique disclosed in the present specification can be realized in various forms, and includes, for example, a current collector-fuel cell single cell complex, a fuel cell power generation unit, and a plurality of fuel cell power generation units. Fuel cell stack, power generation module with fuel cell stack, fuel cell system with power generation module, current collector-electrolytic cell complex, electrolytic cell unit, electrolytic cell stack with multiple electrolytic cell units, hydrogen with electrolytic cell stack It can be realized in the form of a generation module, a hydrogen generation system including a hydrogen generation module, or the like.

It is a perspective view which shows the appearance structure of the fuel cell stack 100 in embodiment. It is explanatory drawing (XZ sectional view) which shows schematic structure of the power generation unit 102. It is explanatory drawing (YZ sectional view) which shows schematic structure of the power generation unit 102. It is explanatory drawing (XY sectional view) which shows schematic structure of the power generation unit 102. It is explanatory drawing (XY sectional view) which shows schematic structure of the power generation unit 102. It is explanatory drawing which enlarges and shows the structure of the X1 part (current collector element 135, the junction layer 138 and the air electrode 114) in FIG. It is explanatory drawing which shows the diffusion effect of the oxidant gas OG in the complex 200 of an Example and the complex 200X of a comparative example. It is explanatory drawing which shows the performance evaluation result.

A. Embodiment:
A-1. Constitution:
(Structure of fuel cell stack 100)
FIG. 1 is an external perspective view schematically showing the configuration of the fuel cell stack 100 in the present embodiment. FIG. 1 shows XYZ axes that are orthogonal to each other to specify the direction. In the present specification, for convenience, the Z-axis positive direction is referred to as an upward direction, and the Z-axis negative direction is referred to as a downward direction, but the fuel cell stack 100 is installed in a direction different from such an orientation. May be good. The same applies to FIGS. 2 and later.

The fuel cell stack 100 is arranged so as to sandwich a plurality of (seven in this embodiment) power generation units 102 arranged side by side in a predetermined arrangement direction (vertical direction in this embodiment) and seven power generation units 102 from above and below. It is provided with a pair of end plates 104 and 106. The number of power generation units 102 included in the fuel cell stack 100 shown in FIG. 1 is merely an example, and the number of power generation units 102 is appropriately determined according to the output voltage and the like required for the fuel cell stack 100. The arrangement direction (vertical direction) corresponds to the first direction in the claims.

A plurality of (eight in this embodiment) through holes 108 extending in the vertical direction from the upper end plate 104 to the lower end plate 106 are formed on the peripheral edge of the fuel cell stack 100 in the Z direction. Each layer constituting the fuel cell stack 100 is tightened and fixed by a bolt 22 inserted into each through hole 108 and a nut 24 fitted in the bolt 22.

The outer diameter of the shaft portion of each bolt 22 is smaller than the inner diameter of each through 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 through hole 108. Bolt 22 (bolt 22A) and a through hole located near the midpoint of one side (the side on the positive side of the X axis of the two sides parallel to the Y axis) on the outer circumference of the fuel cell stack 100 around the Z direction. The space formed by the 108 and the oxidant gas OG is introduced from the outside of the fuel cell stack 100 and functions as an oxidant gas introduction manifold 161 which is a gas flow path for supplying the oxidant gas OG to each power generation unit 102. However, it is formed by a bolt 22 (bolt 22B) located near the midpoint of the side opposite to the side (the side on the negative side of the X-axis of the two sides parallel to the Y-axis) and the through hole 108. The space functions as an oxidant gas discharge manifold 162 that discharges the oxidant off-gas OOG, which is the gas discharged from the air chamber 166 of each power generation unit 102, to the outside of the fuel cell stack 100 (see FIG. 2). Further, with the bolt 22 (bolt 22D) located near the middle point of the other side (the side on the positive direction side of the Y axis among the two sides parallel to the X axis) on the outer circumference of the fuel cell stack 100 around the Z direction. The space formed by the through hole 108 functions as a fuel gas introduction manifold 171 in which the fuel gas FG is introduced from the outside of the fuel cell stack 100 and supplies the fuel gas FG to each power generation unit 102, and is opposite to the side thereof. The space formed by the bolt 22 (bolt 22E) located near the midpoint of the side side (the side in the negative direction of the Y axis of the two sides parallel to the X axis) and the through hole 108 is each power generation. It functions as a fuel gas discharge manifold 172 that discharges the fuel off-gas FOG, which is the gas discharged from the fuel chamber 176 of the unit 102, to the outside of the fuel cell stack 100 (see FIG. 3). In the present embodiment, for example, air is used as the oxidant gas OG, and hydrogen-rich gas obtained by modifying, for example, city gas is used as the fuel gas FG.

(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 in a pressed state. 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.

(Structure of power generation unit 102)
2 to 5 are explanatory views schematically showing the configuration of the power generation unit 102. FIG. 2 shows the cross-sectional configuration of the power generation unit 102 at the position of II-II in FIGS. 1, 4 and 5, and FIG. 3 shows the position of III-III in FIGS. 1, 4 and 5. The cross-sectional configuration of the power generation unit 102 in FIG. 4 is shown, FIG. 4 shows the cross-sectional configuration of the power generation unit 102 at the position of IV-IV in FIG. 2, and FIG. 5 shows the position of VV in FIG. The cross-sectional structure of the power generation unit 102 in the above is shown.

As shown in FIGS. 2 and 3, the power generation unit 102, which is the minimum unit of power generation, includes a single cell 110, a separator 120, an air pole side frame 130, an air pole side current collector 134, and a fuel pole side frame. It includes 140, a fuel electrode side current collector 144, and a pair of interconnectors 150 that form the uppermost layer and the lowermost layer of the power generation unit 102. Holes corresponding to the through holes 108 into which the bolts 22 described above are inserted are formed in the peripheral edges of the separator 120, the air pole side frame 130, the fuel pole side frame 140, and the interconnector 150 in the Z direction.

The interconnector 150 is a substantially rectangular flat plate-shaped conductive member, and is made of, for example, ferritic stainless steel. The interconnector 150 ensures electrical continuity between the power generation units 102 and prevents mixing of reaction gases between the power generation units 102. In the present embodiment, when two power generation units 102 are arranged adjacent to each other, one interconnector 150 is shared by 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 a pair of end plates 104 and 106, the power generation unit 102 located at the top of the fuel cell stack 100 does not have the upper interconnector 150 and is located at the bottom. The power generation unit 102 does not include the lower interconnector 150.

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

The electrolyte layer 112 is a substantially rectangular flat plate-shaped member and contains at least Zr, and solid oxides such as YSZ (yttria-stabilized zirconia), ScSZ (scandia-stabilized zirconia), and CaSZ (calcia-stabilized zirconia). It is formed by objects. 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 (lanternstrontium cobalt iron oxide), LSM (lanternstrontium manganese oxide), LNF (lantern 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 composed of Ni and ceramic particles, a Ni-based alloy, or the like. As described above, the single cell 110 (power generation unit 102) of the present embodiment is a solid oxide fuel cell (SOFC) that uses a solid oxide as an electrolyte.

The separator 120 is a frame-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 edge of the surface of the electrolyte layer 112 on the side of the air electrode 114. The separator 120 is bonded to the electrolyte layer 112 (single cell 110) by a bonding portion 124 formed of a brazing material (for example, Ag wax) arranged at the opposite portion thereof. The separator 120 partitions the air chamber 166 facing the air electrode 114 and the fuel chamber 176 facing the fuel electrode 116, and a gas leak from one electrode side to the other electrode side at the peripheral edge of the single cell 110. It is suppressed. The single cell 110 to which the separator 120 is joined is also referred to as a single cell with a separator.

As shown in FIGS. 2 to 4, 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, for example, an insulator such as mica. Has been done. 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, the oxidant gas supply communication hole 132 that communicates the oxidant gas introduction manifold 161 and the air chamber 166, and the oxidant gas that communicates the air chamber 166 and the oxidant gas discharge manifold 162. A discharge communication hole 133 is formed.

As shown in FIGS. 2, 3 and 5, the fuel pole 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 formed of, for example, metal. ing. 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 of the surface of the separator 120 facing the electrolyte layer 112 and the peripheral edge 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.

As shown in FIGS. 2, 3 and 5, 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, a plurality of electrode facing portions 145, and a connecting portion 147 connecting each electrode facing portion 145 and the interconnector facing portion 146, for example, nickel. It is made of nickel alloy, stainless steel, etc. Specifically, the fuel electrode side current collector 144 is manufactured by making a notch in a square flat plate member and processing the plurality of square portions so as to bend them up. The bent square portion becomes the electrode facing portion 145, the flat plate portion in a perforated state other than the bent portion becomes 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. In addition, in the partially enlarged view in FIG. 5, in order to show the manufacturing method of the fuel electrode side current collector 144, the state before the bending raising process of a part of a plurality of square portions is completed is shown. The electrode facing portion 145 is in contact with the surface of the fuel pole 116 opposite to the side facing the electrolyte layer 112, and the interconnector facing portion 146 is on the surface of the interconnector 150 facing the fuel pole 116. Are in contact. However, as described above, since the power generation unit 102 located at the bottom of the fuel cell stack 100 does not have the lower interconnector 150, the interconnector facing portion 146 in the power generation unit 102 is the lower end plate. It is in contact with 106. Since the fuel pole side current collector 144 has such a configuration, the fuel pole 116 and the interconnector 150 (or the end plate 106) are electrically connected to each other. A spacer 149 formed of, for example, mica is arranged between the electrode facing portion 145 and the interconnector facing portion 146. Therefore, the fuel pole 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 pole 116 and the interconnector 150 (or the end plate 106) via the fuel pole side current collector 144 follow. Good electrical connection with is maintained.

As shown in FIGS. 2 to 4, 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 columnar current collector elements 135, and is formed of, for example, a metal containing Cr (chromium) such as ferritic stainless steel. The air pole side current collector 134 is in contact with the surface of the air pole 114 on the side opposite to the side facing the electrolyte layer 112 and the surface of the interconnector 150 on the side facing the air pole 114. However, as described above, since the power generation unit 102 located at the top of the fuel cell stack 100 does not have the upper interconnector 150, the air electrode side current collector 134 in the power generation unit 102 has an 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. The air electrode side current collector 134 and the interconnector 150 may be formed as an integral member. In the present embodiment, the air electrode 114 corresponds to one electrode in the claims, the air electrode side current collector 134 corresponds to the current collector member in the claims, and the current collector element 135 is Corresponds to the protruding part in the claims.

As shown in FIGS. 2 and 3, the surface of the air electrode side current collector 134 is covered with a conductive coat 136. The coat 136 contains a spinel-type oxide containing at least one of Zn (zinc), Mn (manganese), Co (cobalt), and Cu (copper) (for example, Mn _1.5 Co _1.5 O ₄ or _{Mn Co 2).} It is formed of O ₄ , ZnCo ₂ O ₄ , ZnMnCoO ₄ , and CuMn ₂ O ₄ ). The formation of the coat 136 on the surface of the air electrode side current collector 134 is performed by a well-known method such as spray coating, inkjet printing, spin coating, dip coating, plating, sputtering, and thermal spraying. As described above, in the present embodiment, the air electrode side current collector 134 and the interconnector 150 are formed as an integral member. Therefore, in reality, the interface with the interconnector 150 in the surface of the air electrode side current collector 134 is not covered by the coat 136, while at least the flow path of the oxidant gas in the surface of the interconnector 150. The surface facing the surface (that is, the surface of the interconnector 150 on the air electrode 114 side, the surface facing the through hole 108 constituting the oxidant gas introduction manifold 161 and the oxidant gas discharge manifold 162, etc.) is covered with the coat 136. There is. Further, a film of chromium oxide may be formed by heat treatment on the air electrode side current collector 134. In that case, the coat 136 is not the film, but the air electrode side current collector 134 on which the film is formed. It is a layer formed to cover. In the following description, unless otherwise specified, the air electrode side current collector 134 (or current collector element 135) means "air pole side current collector 134 (or current collector element 135) covered with coat 136". To do.

The air electrode 114 and the air electrode side current collector 134 are bonded by a conductive bonding layer 138. Bonding layer 138, similar to the coating 136, spinel type oxide containing at least one of Zn and Mn and Co and Cu _(e.g., Mn _{1.5 Co} 1.5 _{O 4} and MnCo ₂ O _4, ZnCo ₂ It is formed of O ₄ , ZnMnCoO ₄ , CuMn ₂ O ₄ ). In this embodiment, the coat 136 and the bonding layer 138 are formed of spinel-type oxides having the same main component elements. The main component element referred to here is a metal element constituting a spinel-type oxide. In addition, identification of spinel-type oxides can be realized by performing X-ray diffraction and elemental analysis. The bonding layer 138 is printed on, for example, a portion of the surface of the air electrode 114 where the paste for the bonding layer faces the tip of each current collector element 135 constituting the air electrode side current collector 134. It is formed by firing under predetermined conditions with the tip of the electric body element 135 pressed against the paste. The bonding layer 138 electrically connects the air electrode 114 and the air electrode side current collector 134. I mentioned earlier that the air pole side current collector 134 is in contact with the surface of the air pole 114, but to be precise, the air pole side current collector 134 (covered by the coat 136) and the air pole 114. A bonding layer 138 is interposed between them. The joint layer 138 corresponds to the joint in the claims. Further, the complex including the single cell 110, the air electrode side current collector 134, and the junction layer 138 (hereinafter referred to as “complex 200”) is a current collector-electrochemical reaction single cell complex within the scope of the claims. Is. The detailed configuration of the current collector element 135 (current collector 134 on the air electrode side) and the junction layer 138 will be described later.

A-2. Power generation operation in the fuel cell stack 100:
As shown in FIG. 2, when the oxidant gas OG is supplied to the oxidant gas introduction manifold 161, the oxidant gas OG passes the oxidant gas supply communication hole 132 of each power generation unit 102 from the oxidant gas introduction manifold 161. After that, it is supplied to the air chamber 166. Further, as shown in FIG. 3, when the fuel gas FG is supplied to the fuel gas introduction manifold 171, the fuel gas FG passes through the fuel gas supply communication hole 142 of each power generation unit 102 from the fuel gas introduction manifold 171 and fuels. It is supplied to room 176.

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, power is generated by the electrochemical reaction of the oxidant gas OG and the fuel gas FG in the single cell 110. Will be. In each power generation unit 102, the air pole 114 of the single cell 110 is electrically connected to one of the interconnectors 150 via an air pole side current collector 134 (and coat 136, junction layer 138), and the fuel pole 116 is fuel. It is electrically connected to the other interconnector 150 via the pole side current collector 144. Further, the plurality of power generation units 102 included in the fuel cell stack 100 are 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 electricity at a relatively high temperature (for example, 700 to 1000 degrees Celsius), the fuel cell stack 100 is a heater until the high temperature can be maintained by the heat generated by the power generation after the start-up. May be heated by.

As shown in FIG. 2, the oxidant off-gas OOG (oxidant gas not used in the power generation reaction in each power generation unit 102) passes from the air chamber 166 through the oxidant gas discharge communication hole 133 and the oxidant gas discharge manifold 162. , Is discharged to the outside of the fuel cell stack 100. Further, as shown in FIG. 3, the fuel off-gas FOG (fuel gas not used for the power generation reaction in each power generation unit 102) passes from the fuel chamber 176 through the fuel gas discharge communication hole 143 and the fuel gas discharge manifold 172 to fuel the fuel. It is discharged to the outside of the battery stack 100.

A-3. Detailed configuration of current collector element 135 and junction layer 138:
FIG. 6 is an enlarged explanatory view showing the configuration of the X1 portion (current collector element 135, junction layer 138 and air electrode 114) in FIG. As shown in FIGS. 3 and 6, the current collector element 135 projects from the interconnector 150 toward the air pole 114 and is separated from the air pole 114. In the present embodiment, in a cross section parallel to the vertical direction including the current collector element 135, the junction layer 138, and the air pole 114 (hereinafter, referred to as “YZ cross section of the current collector element 135 or the like”), the air pole side collection. The width in the lateral direction (Y-axis direction) substantially orthogonal to the vertical direction (Z-axis direction) of each current collector element 135 constituting the electric body 134 is substantially the same over the entire length of the current collector element 135 in the vertical direction. ing. Further, the bonding layer 138 has pores. Specifically, the bonding layer 138 is a porous body. Therefore, the oxidant gas OG from the air chamber 166 diffuses into the bonding layer 138.

Further, in the YZ cross section of the current collector element 135 or the like, the bonding layer 138 satisfies the following first requirement (first requirement A to first requirement C).
First Requirement A: "The bonding layer 138 includes a central portion 138A and an end portion 138B located on at least one side in the lateral direction (Y direction) with respect to the central portion 138A."
The central portion 138A is a portion of the bonding layer 138 located between the current collector element 135 and the air electrode 114 in the vertical direction (Z direction). The end portion 138B is a portion of the joint layer 138 located laterally to the central portion 138A in the lateral direction. The end portion 138B is located on the lateral end side of the outline of the current collector element 135 and covers at least a part of the side sides substantially parallel to the vertical direction. In FIG. 6, end portions 138B are located on both sides of the central portion 138A in the joint layer 138 in the lateral direction.

First Requirement B: "The outline of the end portion 138B facing the air chamber 166 is inclined so as to be separated from the central portion 138A of the joint layer 138 as it approaches the air pole 114, and is on the central portion 138A side. Contains curved lines that are curved. "
In FIG. 6, the outlines of the two end portions 138B located on both sides in the lateral direction (Y direction) in the junction layer 138 joining one current collector element 135 are separated from each other as they approach the air pole 114. It includes an inclined curved line 138C which is inclined and curved toward the central portion 138A.

First requirement C: "Connecting the first position P1 and the second position P2 to the area of the virtual triangle whose vertices are the first position P1, the second position P2, and the third position P3. The ratio of the area of the specific region R surrounded by the fourth virtual straight line L4 and the inclined curved line 138C is 20% or more. "
The first position P1 is a position where the first virtual straight line L1 and the outline of the end portion 138B intersect. The first virtual straight line L1 is a virtual straight line that passes through a portion closest to the air pole 114 at the boundary between the current collector element 135 and the end portion 138B of the junction layer 138 and is parallel to the lateral direction (Y direction). ..
The second position P2 is a position on the outer line of the end portion 138B at the portion closest to the central portion 138A among the portions having the thinnest vertical (Z direction) thickness of the end portion 138B.
The third position P3 is a position where the second virtual straight line L2 and the third virtual straight line L3 intersect. The second virtual straight line L2 is a virtual straight line that passes through the first position P1 and is parallel in the vertical direction. The third virtual straight line L3 is a virtual straight line that passes through the second position P2 and is parallel to the lateral direction. It should be noted that each position, virtual straight line, etc. can be specified from the SEM image when the cross section (YZ cross section) parallel to the vertical direction of the current collector element 135 is photographed with a scanning electron microscope (SEM). .. At this time, the vertical line segment between the first position P1 and the third position P3 and the horizontal line segment between the second position P2 and the third position P3 are parallel to the line segment in the SEM image. It is preferable to shoot at a magnification of 1/2 or more (more preferably 3/4 or more) of the width in the direction. Further, regarding the identification of the inclined curved line 138C, for example, using a digital microscope (VHX-5000 manufactured by KEYENCE CORPORATION), a plurality of straight lines arranged at predetermined intervals in a direction orthogonal to the vertical line segment or the horizontal line segment in the SEM image. It is preferable that the intersection with the outer line of the end portion 138B is connected.

Further, in the YZ cross section of the current collector element 135 or the like, the bonding layer 138 satisfies the second requirement below.
Second requirement: "The first distance ΔZ between the first position P1 and the third position P3 is longer than the second distance ΔY between the second position P2 and the third position P3. . "

Further, in the YZ cross section of the current collector element 135 or the like, the bonding layer 138 satisfies the following third requirement.
Third requirement: "The end portions 138B of the bonding layers 138 that join each of the two current collector elements 135 adjacent to each other and the air electrode 114 are connected to each other."
As described above, when the bonding layer 138 satisfies the third requirement, the entire surface of the air electrode 114 on the air electrode side current collector 134 side is opposed to the current collector element 135 in a plan view. The bonding layer 138 is integrally formed not only in the regions but also in the non-opposing regions between the opposing regions adjacent to each other. Further, in the complex 200 of the present embodiment, the bonding layer 138 satisfies the third requirement in both directions (Y direction and X direction) orthogonal to each other. Further, in the complex 200 of the present embodiment, the bonding layer 138 is formed in a region of 90% or more of the entire surface of the air electrode 114 on the air electrode side current collector 134 side.

In addition, as an example of the manufacturing method of the bonding layer 138 satisfying the first requirement and the second requirement, there are the following method 1 and method 2.
Method 1: In the firing step for joining the current collector element 135 and the air electrode 114 described above, a method of adjusting the firing shrinkage rate of the bonding layer 138 when the bonding layer 138 is formed from the paste for the bonding layer. Is. The larger the firing shrinkage rate of the bonding layer 138, the more easily the outer line of the end portion 138B of the bonding layer 138 is curved. Therefore, by adjusting the firing shrinkage rate of the bonding layer 138, the bonding layer 138 satisfying the first requirement and the second requirement can be manufactured. In order to increase the firing shrinkage rate of the bonding layer 138, for example, the content of the binder contained in the paste for the bonding layer may be increased, or the particles of the metal material (Zn or the like) contained in the paste for the bonding layer may be increased. The diameter may be reduced.
Method 2: By applying a paste for one bonding layer on the air electrode 114 and drying it, and then applying a paste for another bonding layer on the paste for one bonding layer after drying and drying it. is there. At this time, by making the firing shrinkage rate of the paste for another bonding layer larger than the firing shrinkage rate of the paste for one bonding layer, the outer line of the end portion 138B of the bonding layer 138 is likely to be curved. A bonding layer 138 that satisfies the first requirement and the second requirement can be manufactured.

A-4. Effect of this embodiment:
As described above, in the composite 200 of the present embodiment, the bonding layer 138 has the above-mentioned first requirement A “the bonding layer 138 has the central portion 138A and the center in the YZ cross section of the current collector element 135 or the like. The end portion 138B located on at least one side in the lateral direction (Y direction) with respect to the portion 138A is included. ” Therefore, according to the composite 200 of the present embodiment, the contact area between the bonding layer 138 and the air electrode 114 is wider than that in the configuration in which the bonding layer 138 does not include the end portion 138B, and as a result, the current collector element. The joint strength between the 135 and the air electrode 114 can be increased.

Further, in the composite 200 of the present embodiment, the joint layer 138 has an outer line facing the air chamber 166 of the first requirement B “end portion 138B” in the YZ cross section of the current collector element 135 or the like, and the outer line faces the air pole 114. It is separated from the central portion 138A of the joint layer 138 as it approaches, and includes a curved line curved toward the central portion 138A. ” The ratio is 20% or more. " Therefore, according to the complex 200 of the present embodiment, the oxidizing agent from the air chamber 166 is located in the central portion 138A of the bonding layer 138, as compared with the configuration in which the outer line of the end portion 138B of the bonding layer 138 is an inclined straight line. It is possible to prevent the performance of the complex 200 from being deteriorated due to insufficient diffusion of the gas OG. This point will be explained in detail next.

FIG. 7 is an explanatory diagram showing the diffusion effect of the oxidant gas OG in the complex 200 of the example and the complex 200X of the comparative example. The composite 200 of the embodiment has a configuration in which the outer line of the end portion 138B of the joint layer 138 is an inclined curved line 138C, and the joint layer 138 satisfies all of the above-mentioned first requirements A to C. The composite 200X of the comparative example has a configuration in which the outline of the end portion 138BX of the bonding layer 138X is an inclined straight line 138CX, and the bonding layer 138 satisfies the above-mentioned first requirement A, but the first requirement B, Does not satisfy C.

The shaded area H in FIG. 7 means a region near the exposed surface in which the distance from the outer lines of the end portions 138B and 138BX of the bonding layers 138 and 138X (exposed surfaces of the bonding layers 138 and 138X) is within a predetermined distance. To do. Further, a graph showing the distribution of the current density is shown on the lower side of FIG. 7. As shown in FIG. 7, the current density is high in the central portions 138A and 138AX (particularly near the interface with the air electrode 114) of the bonding layers 138 and 138X, which contributes to the power generation reaction (ionization reaction of the oxidant gas OG). There are many electrons that do. Therefore, the higher the diffusibility of the oxidant gas OG from the air chamber 166 to the central portions 138A and 138AX of the bonding layers 138 and 138X, the more the composite 200 and 200X with respect to the supply amount of the oxidant gas OG to the air chamber 166. Since the amount of power generation is large, the power generation efficiency of the composite 200, 200X is high, and the power generation performance of the fuel cell stack 100 (complex 200, 200X) can be improved.

However, in the composite 200X of the comparative example, the outer line of the end portion 138BX of the bonding layer 138X is an inclined straight line 138CX. Therefore, as a whole, the distance between the outline of the end portion 138BX of the bonding layer 138X (exposed surface of the bonding layer 138X) and the central portion 138AX of the bonding layer 138X (particularly near the interface with the air electrode 114) is long. .. Therefore, the power generation performance of the complex 200X deteriorates due to the fact that the oxidant gas OG from the air chamber 166 is not sufficiently diffused into the central portion 138AX of the bonding layer 138X. On the other hand, in the composite 200 of the embodiment, the outer line of the end portion 138B of the joint layer 138 is the inclined curved line 138C. Therefore, as a whole, the distance between the outline of the end portion 138B of the junction layer 138 (exposed surface of the junction layer 138) and the central portion 138A of the junction layer 138 (particularly near the interface with the air electrode 114) is short. .. Therefore, it is possible to suppress a decrease in the power generation performance of the complex 200X due to insufficient diffusion of the oxidant gas OG from the air chamber 166 into the central portion 138A of the bonding layer 138.

According to the composite 200 of the present embodiment, for example, as compared with the configuration in which the outer line of the end portion 138B of the joint layer 138 is a broken line, the composite 200 is damaged due to stress concentration at a specific portion of the joint layer 138. Etc. can be suppressed.

Further, in the composite 200 of the present embodiment, the bonding layer 138 is the first requirement "between the first position P1 and the third position P3" in the YZ cross section of the current collector element 135 and the like. The distance ΔZ is longer than the second distance ΔY between the second position P2 and the third position P3. ” Therefore, according to the composite 200 of the present embodiment, the entire exposed surface of the end portion 138B of the bonding layer 138 is closer to the central portion 138A as compared with the configuration in which the first distance ΔZ is shorter than the second distance ΔY. As a result, the oxidant gas OG from the air chamber 166 is easily diffused into the central portion 138A, so that the deterioration of the power generation performance of the complex 200 due to the insufficient diffusion of the oxidant gas OG can be more effectively suppressed. it can.

Further, in the composite 200 of the present embodiment, the bonding layer 138 has the third requirement "each of the two current collector elements 135 adjacent to each other and the air electrode 114" in the YZ cross section of the current collector element 135 or the like. The end portions 138B of the joining layers 138 to be joined are connected to each other. " Therefore, according to the composite 200 of the present embodiment, the separation between the bonding layer 138 and the air electrode 114 is suppressed as compared with the configuration in which the end portions 138B of the bonding layers 138 adjacent to each other are separated from each other. can do.

A-5. Performance evaluation:
Samples of a plurality of complexes were prepared, and performance evaluation was performed using the samples of the prepared multiple complexes. FIG. 8 is an explanatory diagram showing the performance evaluation result. This performance evaluation will be described below. The unit of the numerical values in the "specific area R area" column and the "virtual triangle area" column in FIG. 8 is μm ² . Further, the "area ratio" in FIG. 8 means the ratio of the area of the specific region R to the area of the above-mentioned virtual triangle. Further, "○" in each requirement column in FIG. 8 means that each requirement is satisfied, and "x" means that the same requirement is not satisfied. Further, the unit of the numerical values in the "first distance ΔZ" column and the "second distance ΔY" column in FIG. 8 is μm. Further, "determination" in FIG. 8 means the evaluation result of the power generation performance of each sample. Specifically, a fuel cell stack including a plurality of samples is configured, and for example, a voltage per composite (single cell) when power generation operation is performed at a ^{temperature of 700 ° C. and a current density of 0.5 A / cm 2.} (Power generation output) was measured. “X” in the “judgment” column indicates that the measured value of the voltage in Comparative Example 1 is used as the reference voltage, and the rate of increase (improvement rate) of the measured value of the voltage in other samples with respect to the reference voltage is less than 2%. means. "○" in the "judgment" column means that the rate of increase is 2% or more and 4% or less, and "◎" in the "judgment" column means that the rate of increase is greater than 4%. ..

A-5-1. For each sample:
As shown in FIG. 8, the performance evaluation of the complex was carried out for Comparative Examples 1 and 2 and Examples 1 to 3. In Comparative Example 1, the area ratio is 7.1%, which does not satisfy the first requirement (first requirement C). However, Comparative Example 1 satisfies the second requirement. In Comparative Example 2, the area ratio is 14.4%, which does not satisfy the first requirement (first requirement C) and does not satisfy the second requirement. On the other hand, Example 1 has an area ratio of 25.8%, Example 2 has an area ratio of 41.6%, and Example 3 has an area ratio of 48.6%. All of ~ 3 satisfy the first requirement. However, Examples 1 and 2 do not satisfy the second requirement, and only Example 3 satisfies the second requirement.

A-5-2. Evaluation results:
As shown in FIG. 8, in Comparative Examples 1 and 2, it was determined that all of them were defective (x) in the evaluation of the power generation characteristics. On the other hand, in Examples 1 to 3, it was determined that all of them were good (◯) or better in the evaluation of the power generation characteristics. From this evaluation result, it can be seen that the power generation characteristics of the complex can be improved by satisfying the first requirement including that the ratio of the area of R to the area of the virtual triangle is 20% or more. In the configuration in which the area ratio is less than 20% as in Comparative Examples 1 and 2, since the outer line of the end portion of the joint layer is also substantially linear, the outer line of the end portion (exposed surface of the joint layer). The distance between and the central part of the junction layer (especially near the interface with the air electrode) is long. Therefore, it is considered that the power generation performance of the complex is low due to the fact that the oxidant gas from the air chamber is not sufficiently diffused in the central portion of the bonding layer.

Further, in Example 3, it was determined to be the best (⊚) in the evaluation of the power generation characteristics. In the third embodiment, by further satisfying the second requirement, the entire exposed surface of the end portion of the junction layer is closer to the central portion of the junction layer as compared with the first and second embodiments, so that the air chamber is released from the air chamber. It is considered that the oxidant gas is easily diffused to the central portion, and as a result, the deterioration of the performance of the complex due to the insufficient diffusion of the oxidant gas is suppressed more effectively. Further, according to the evaluation results of Examples 1 to 3, the area ratio is more preferably 45% or more.

B. Modification example:
The technique disclosed in the present specification is not limited to each of the above-described embodiments, and can be transformed into various forms without departing from the gist thereof, and for example, the following modifications are also possible.

In the above embodiment, the bonding layer 138 is assumed to satisfy all of the first to third requirements, but it is sufficient that at least the first requirement is satisfied, and at least the second and third requirements are satisfied. It may not satisfy one. For example, the end portions 138B of the bonding layers 138 that join each of the two adjacent current collector elements 135 and the air electrode 114 are not connected to each other, and the non-opposing region of the air electrode side current collector 134 is formed. It may be exposed. Further, in the above embodiment, the first requirement is satisfied for each of the two end portions 138B located on both sides of the central portion 138A in the bonding layer 138, but at least one of the two end portions 138B is the first. The effect of the present invention can be obtained if the requirement of 1 is satisfied. Further, in the above embodiment, it is assumed that all the current collector elements 135 constituting the air electrode side current collector 134 satisfy the first requirement, but the present invention is not limited to this, and at least one current collector element 135 is satisfied. , The first requirement may be satisfied. Further, in the above embodiment, the bonding layer 138 satisfies the first requirement in the two cross sections (XZ cross section and YZ cross section) parallel to the vertical direction of the current collector element 135 and the like and orthogonal to each other. The joint layer 138 may satisfy the first requirement in at least one cross section (YZ cross section) parallel to the vertical direction of the electric body element 135 or the like. For example, the bonding layer 138 may satisfy the first requirement in all the cross sections parallel to the vertical direction such as the current collector element 135.

Further, in the above embodiment, the width of the current collector element 135 in the lateral direction (Y-axis direction) is substantially the same over the entire length of the current collector element 135 in the vertical direction. The width of the air electrode 114 may be narrowed as it approaches the air electrode 114.

Further, in the above embodiment, the end portion 138B may not cover the side side of the outer line of the current collector element 135 that is located on the end side in the horizontal direction and is substantially parallel to the vertical direction. For example, the upper end of the end portion 138B may be in contact with the facing surface (lower surface) of the current collector element 135 with the air electrode 114.

Further, in the above embodiment, an example in which the present invention is applied to a configuration in which a protruding portion of a current collector member arranged on the air electrode side of a single cell and an air electrode are joined by a conductive joint portion has been described. The present invention may be applied to a configuration in which a protruding portion of a current collector member arranged on the fuel electrode side of a single cell and a fuel electrode are joined by a conductive joint portion.

Further, in each of the above embodiments, the coat 136 and the bonding layer 138 are formed of spinel-type oxides having the same main component elements, but are formed of spinel-type oxides having different main component elements. May be good. Further, in each of the above embodiments, the coat 136 and the bonding layer 138 are formed of a spinel-type oxide containing at least one of Zn, Mn, Co, and Cu, but the spinel-type oxidation does not contain these elements. It may be formed of an object. Further, in each of the above embodiments, the coat 136 and the bonding layer 138 are formed of a spinel-type oxide, but may be formed of another material such as a perovskite-type oxide. Further, in the above embodiment, the current collector element 135 may not be covered with the coat 136.

Further, in each of the above embodiments, the electrolyte layer 112 is formed of a solid oxide, but the electrolyte layer 112 may contain other substances in addition to the solid oxide. Further, the material forming each member in each of the above embodiments is merely an example, and each member may be formed of another material. For example, in each of the above embodiments, the air electrode side current collector 134 is formed of a metal containing Cr, but the air electrode side current collector 134 is formed of another material if it is covered with the coat 136. It may have been done. Further, the shape of each current collector element 135 constituting the air pole side current collector 134 is not limited to a square columnar shape, and any other shape may be used as long as it protrudes from the interconnector 150 side to the air pole 114 side. There may be.

Further, in each of the above embodiments, a reaction prevention layer containing, for example, ceria is provided between the electrolyte layer 112 and the air electrode 114, and zirconium or the like in the electrolyte layer 112 reacts with strontium or the like in the air electrode 114. The increase in electrical resistance between the electrolyte layer 112 and the air electrode 114 may be suppressed. Further, in each of the above embodiments, the air electrode side current collector 134 and the adjacent interconnector 150 may be separate members. Further, the fuel pole side current collector 144 may have the same configuration as the air pole side current collector 134, and the fuel pole side current collector 144 and the adjacent interconnector 150 may be an integral member. Good. Further, the fuel pole side frame 140 may be an insulator instead of the air pole side frame 130. Further, the air pole side frame 130 and the fuel pole side frame 140 may have a multi-layer structure.

Further, in the above embodiment, the current collector element 135 satisfies the first requirement for all the power generation units 102 included in the fuel cell stack 100, but at least one power generation unit 102 included in the fuel cell stack 100. With such a configuration, it is possible to suppress the deterioration of the performance of the complex 200 due to the insufficient diffusion of the oxidant gas OG from the air chamber 166.

Further, in the above embodiment, the fuel cell stack 100 has a configuration in which a plurality of flat plate-shaped single cells 110 are laminated, but the present invention is described in another configuration, for example, International Publication No. 2012/1655409. As described above, the same applies to a configuration in which a plurality of substantially cylindrical fuel cell single cells are connected in series.

Further, in the above embodiment, the SOFC that generates power by utilizing the electrochemical reaction between hydrogen contained in the fuel gas and oxygen contained in the oxidizing agent gas is targeted, but the present invention comprises an electrolysis reaction of water. It is also applicable to an electrolytic cell unit, which is the smallest unit of a solid oxide fuel cell (SOEC) that uses it to generate hydrogen, and an electrolytic cell stack having a plurality of electrolytic cell units. The configuration of the electrolytic cell stack is not described in detail here because it is known as described in, for example, Japanese Patent Application Laid-Open No. 2016-81813, but is generally the same as the fuel cell stack 100 in the above-described embodiment. It is the composition of. That is, the fuel cell stack 100 in the above-described embodiment may be read as an electrolytic cell stack, and the power generation unit 102 may be read as an electrolytic cell unit. However, during the operation of the electrolytic cell stack, a voltage is applied between both electrodes so that the air electrode 114 is positive (anode) and the fuel electrode 116 is negative (cathode), and the voltage is applied through the through hole 108. Water vapor 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 through hole 108. Even in the electrolytic cell unit and the electrolytic cell stack having such a configuration, if the current collector element 135 satisfies at least the first requirement as in the above embodiment, the gas from the gas chamber is sufficiently sufficient. It is possible to suppress the deterioration of the performance of the current collector-electrochemical reaction single cell complex due to the non-diffusion. It plays the effect.

22: Bolt 24: Nut 100: Fuel cell stack 102: Power generation unit 104, 106: End plate 108: Through hole 110: Single cell 112: Electrolyte layer 114: Air pole 116: Fuel pole 120: Separator 121: Hole 124: Join Part 130: Air electrode side frame 131: Hole 132: Oxidizing agent gas supply communication hole 133: Oxidizing agent gas discharge communication hole 134: Air electrode side current collector 135: Current collector element 136: Coat 138, 138X: Bonding layer 138A , 138AX: Central part 138B, 138BX: End part 138C: Inclined curved line 138CX: Inclined straight line 140: Fuel pole side frame 141: Hole 142: Fuel gas supply communication hole 143: Fuel gas discharge communication hole 144: Fuel pole side current collection Body 145: Electrode facing part 146: Interconnector facing part 147: Connecting part 149: Spacer 150: Interconnector 161: Oxidizing agent gas introduction manifold 162: Oxidizing agent gas discharge manifold 166: Air chamber 171: Fuel gas introduction manifold 172: Fuel Gas discharge manifold 176: Fuel chamber 200, 200X: Complex FG: Fuel gas FOG: Fuel off gas H: Area near exposed surface L1: First virtual straight line L2: Second virtual straight line L3: Third virtual straight line L4: Fourth virtual straight line OG: Oxidizing agent gas OOG: Oxidizing agent off gas P1: First position P2: Second position P3: Third position R: Specific area Y: First distance Δ Z: Second distance Δ

Claims (4)

A single cell containing an electrolyte layer containing a solid oxide and an air electrode and a fuel electrode facing each other in the first direction across the electrolyte layer.
Wherein disposed on the air electrode side of the unit cell, and the current collecting member having a protruding portion that is spaced apart from the cathode with projecting toward the air electrode,
In a current collector-electrochemical reaction single-cell complex comprising a junction that joins the protrusion and the air electrode and has conductivity and pores.
In at least one cross section parallel to the first direction, including the protrusion, the joint, and the air electrode.
The joint includes a central portion located between the protrusion and the air electrode, and an end portion located on at least one side of the second direction orthogonal to the central portion. , Including,
The outline of the end portion includes a curved line curved toward the central portion so as to move away from the central portion as it approaches the air electrode.
On the outline of the end portion that passes through the portion closest to the air electrode at the boundary between the protrusion and the end portion of the joint and intersects the first virtual straight line parallel to the second direction. Let the position of be the first position
The position of the end portion on the outer line at the portion closest to the central portion among the portions having the thinnest thickness in the first direction at the end portion is defined as the second position.
A second virtual straight line passing through the first position and parallel to the first direction and a third virtual straight line passing through the second position and parallel to the second direction are formed. When the intersecting position is the third position,
The fourth virtual straight line connecting the first position and the second position with respect to the area of the virtual triangle having the first position, the second position, and the third position as vertices and the said. A current collector-electrochemical reaction single cell complex, characterized in that the ratio of the area of a specific region surrounded by a curved line is 20% or more. In the current collector-electrochemical reaction single cell complex according to claim 1.
In the at least one cross section
The first distance between the first position and the third position is longer than the second distance between the second position and the third position. Member-electrochemical reaction single cell complex. In the current collector-electrochemical reaction single cell complex according to claim 1 or 2.
The current collecting member has a plurality of the protruding portions, and the current collecting member has a plurality of the protruding portions.
In the at least one cross section
A current collector-electrochemical reaction single cell complex, characterized in that the end portions of the joints that join each of the two adjacent protrusions and the air electrode are connected to each other. In an electrochemical reaction cell stack with a plurality of current collector-electrochemical reaction single cell complexes.
At least one of the plurality of current collecting member-electrochemical reaction single cell complex is the current collecting member-electrochemical reaction single cell complex according to any one of claims 1 to 3. An electrochemical reaction cell stack characterized by.

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