JP6773600B2 - Electrochemical reaction unit and electrochemical reaction cell stack - Google Patents

Description

The techniques disclosed herein relate to electrochemical reaction units.

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

Further, the power generation unit includes a frame member having a gas chamber hole forming a fuel chamber (gas chamber) facing the fuel electrode of a single cell. In addition to the gas chamber holes, the frame member has a supply-side manifold hole that constitutes a fuel gas supply manifold through which gas supplied to the fuel chamber (hereinafter referred to as "fuel gas") passes, and is discharged from the fuel chamber. A hole for a discharge side manifold that constitutes a fuel gas discharge manifold through which the gas (hereinafter referred to as “fuel off gas”) passes is formed. The frame member further communicates with the supply side manifold hole and opens on the inner peripheral surface of the gas chamber hole, and communicates with the discharge side manifold hole and the inner circumference of the gas chamber hole. A discharge side communication flow path that opens to the surface is formed. Fuel gas is supplied to the fuel chamber of the power generation unit via the fuel gas supply manifold and the supply side communication flow path. Further, the fuel off gas discharged from the fuel chamber through the discharge side communication flow path is discharged to the outside through the fuel gas discharge manifold.

Further, the power generation unit includes a conductive interconnector and a conductive current collector that electrically connects the fuel electrode and the interconnector. The current collector has a plurality of current collectors conducting on the surface of the fuel electrode. The space between the current collector and the current collector of the current collector functions as a gas flow path space facing the fuel electrode (see, for example, Patent Document 1).

JP-A-2017-16909

As the configuration of the interconnector, a configuration in which a plurality of convex portions and a plurality of concave portions are formed on the surface of the side facing the fuel electrode may be adopted. In such a configuration, the main gas flow direction in the fuel chamber (that is, the midpoint of the opening of the supply side communication flow path to the inner peripheral surface of the gas chamber hole and the discharge side communication flow path in the first direction view above). In a cross section orthogonal to the midpoint of the opening to the inner peripheral surface of the gas chamber hole) and parallel to the first direction, the gas chamber is collected between the convex portion of the interconnector and the fuel electrode. When the current collecting part of the electric body is located, the fuel gas supplied to the fuel chamber is blocked by the current collecting part and does not diffuse well in the direction substantially orthogonal to the main gas flow direction, and the performance of the power generation unit. May decrease.

It should be noted that such a problem is common not only to the fuel electrode side but also to the air electrode side. In addition, such a problem is also common to the electrolytic cell unit, which is a constituent unit of a solid oxide fuel cell (hereinafter referred to as “SOEC”) that generates hydrogen by utilizing the electrolysis reaction of water. Is. In this specification, the fuel cell power generation unit and the electrolytic cell unit are collectively referred to as an electrochemical reaction unit. Moreover, such a problem is common not only to SOFC and SOEC but also to other types of electrochemical reaction units.

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

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

(1) The electrochemical reaction unit disclosed in the present specification includes an electrochemical reaction single cell including an electrolyte layer and an air electrode and a fuel electrode facing each other in a first direction across the electrolyte layer. A gas chamber hole forming a gas chamber facing a specific electrode, which is one of the fuel electrode and the air electrode, and a supply side manifold hole forming a supply side manifold through which gas supplied to the gas chamber passes. , The supply-side communication flow that communicates with the discharge-side manifold hole constituting the discharge-side manifold through which the gas discharged from the gas chamber passes and the supply-side manifold hole and opens to the inner peripheral surface of the gas chamber hole. On the frame member on which the path, the discharge side communication flow path communicating with the discharge side manifold hole and opening to the inner peripheral surface of the gas chamber hole, and the surface facing the specific electrode are formed. A conductive interconnector in which a plurality of convex portions and a plurality of concave portions are formed, and a conductive current collector that electrically connects the specific electrode and the interconnector, and each is a surface of the specific electrode. In an electrochemical reaction unit including a current collector having a plurality of current collectors arranged across a gas flow path space facing the specific electrode, and having the same supply in the first direction. A second direction connecting the midpoint of the opening of the gas chamber hole of the side communication flow path to the inner peripheral surface and the midpoint of the opening of the discharge side communication flow path to the inner peripheral surface of the gas chamber hole. In a specific cross section which is at least one cross section orthogonal to and parallel to the first direction, between the specific convex portion which is at least one convex portion formed on the interconnector and the specific electrode. Has the gas flow path space communicating with the first space in the first concave portion adjacent to one side of the specific convex portion. In this electrochemical reaction unit, a current collector is provided between the specific convex portion of the interconnector and the specific electrode in a specific cross section orthogonal to the main gas flow direction (the second direction) in the gas chamber facing the specific electrode. The gas flow path space sandwiched between the current collecting part and the current collecting part is located, and the gas flow path space is a space (first recess) in a recess (first recess) adjacent to the specific convex portion. It communicates with the space). Therefore, according to this electrochemical reaction unit, the gas supplied to the gas chamber facing the specific electrode can be satisfactorily diffused in a direction substantially orthogonal to the main gas flow direction in the gas chamber, and as a result. , The performance of the electrochemical reaction unit can be improved.

(2) In the electrochemical reaction unit, in the specific cross section, between the specific convex portion and the specific electrode, the first concave portion in the first concave portion adjacent to one side of the specific convex portion. The gas flow path space that communicates with the space and the second space in the second recess adjacent to the other side of the specific convex portion may exist. In this electrochemical reaction unit, in a specific cross section orthogonal to the main gas flow direction in the gas chamber facing the specific electrode, between the specific convex portion of the interconnector and the specific electrode, the current collector and the current collector of the current collector The gas flow path space sandwiched between the portions is located, and the gas flow path space is a space (a first recess and a second recess) adjacent to each other on both sides of the specific convex portion. It communicates with the first space and the second space). Therefore, according to the present electrochemical reaction unit, the gas supplied to the gas chamber facing the specific electrode can be more satisfactorily diffused in a direction substantially orthogonal to the main gas flow direction in the gas chamber. As a result, the performance of the electrochemical reaction unit can be effectively improved.

(3) In the electrochemical reaction unit, the gas flow path space located between the specific convex portion and the specific electrode in the specific cross section passes through the first space in the first concave portion. Therefore, it may be configured to communicate with the other gas flow path space. According to this electrochemical reaction unit, the gas supplied to the gas chamber facing the specific electrode can be better diffused in a direction substantially orthogonal to the main gas flow direction in the gas chamber, and as a result, The performance of the electrochemical reaction unit can be improved more effectively.

(4) In the electrochemical reaction unit, in the specific cross section, the first recess may be configured to face a plurality of current collectors in the first direction. In the present electrochemical reaction unit, the gas flow path space located between the specific convex portion and the specific electrode is a plurality of other spaces via the space (first space) in the concave portion (first concave portion). It will communicate with the gas flow path space of. Therefore, according to this electrochemical reaction unit, the gas supplied to the gas chamber facing the specific electrode can be diffused extremely well in a direction substantially orthogonal to the main gas flow direction in the gas chamber. As a result, the performance of the electrochemical reaction unit can be improved extremely effectively.

(5) In the electrochemical reaction unit, the plurality of current collectors of the current collector may be configured not to have gas permeability. In this electrochemical reaction unit, since the current collecting part does not have gas permeability, a decrease in gas diffusivity in a direction substantially orthogonal to the main gas flow direction in the gas chamber facing the specific electrode tends to be a problem. .. However, since each of the above configurations is adopted in this electrochemical reaction unit, the gas supplied to the gas chamber facing the specific electrode is good in a direction substantially orthogonal to the main gas flow direction in the gas chamber. As a result, the performance of the electrochemical reaction unit can be improved.

(6) In the electrochemical reaction unit, the length of the first recess in the direction orthogonal to the second direction in the first direction is the length of the first recess in the second direction. The configuration may be longer than the length. According to the present electrochemical reaction unit, the gas supplied to the gas chamber facing the specific electrode is brought into the space (first space) in the recess (first recess) which is long in the direction orthogonal to the second direction. Can be satisfactorily diffused in a direction substantially orthogonal to the main gas flow direction in the gas chamber, and as a result, the performance of the electrochemical reaction unit can be effectively improved.

(7) In the electrochemical reaction unit, the plurality of recesses formed in the interconnector in the first direction are arranged in a grid pattern in a direction orthogonal to the second direction and in the second direction. The specific cross section may be configured to include a plurality of cross sections that pass through the recesses that are different from each other. According to this electrochemical reaction unit, the gas supplied to the gas chamber facing the specific electrode is substantially orthogonal to the main gas flow direction in the gas chamber at a plurality of positions arranged in the main gas flow direction in the gas chamber. It can be well diffused in the direction, and as a result, the performance of the electrochemical reaction unit can be effectively improved.

(8) In the electrochemical reaction unit, the electrochemical reaction single cell may be configured to be a fuel cell single cell. According to this electrochemical reaction unit, the gas supplied to the gas chamber facing the specific electrode can be satisfactorily diffused in a direction substantially orthogonal to the main gas flow direction in the gas chamber, resulting in electricity. The power generation performance of the chemical reaction single cell can be improved.

The technique disclosed in the present specification can be realized in various forms, for example, an electrochemical reaction unit (fuel cell power generation unit or electrolytic cell unit), and electricity having a plurality of electrochemical reaction units. It can be realized in the form of a chemical reaction cell stack (fuel cell stack or electrolytic cell stack), a method for producing them, and the like.

It is a perspective view which shows the appearance structure of the fuel cell stack 100 in this embodiment. It is explanatory drawing which shows the XZ cross-sectional structure of the fuel cell stack 100 at the position of II-II of FIG. It is explanatory drawing which shows the YZ cross-sectional structure of the fuel cell stack 100 at the position of III-III of FIG. It is explanatory drawing which shows the XZ cross section configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. It is explanatory drawing which shows the YZ cross section configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. It is explanatory drawing which shows the XY cross-sectional structure of the power generation unit 102 at the position of VI-VI of FIG. It is explanatory drawing which shows the XY cross-sectional structure of the power generation unit 102 at the position of VII-VII of FIG. It is explanatory drawing which shows the XY cross-sectional structure of the power generation unit 102 at the position of VIII-VIII of FIG. It is explanatory drawing which shows the detailed structure of the interconnector 150 and the fuel electrode side current collector 144.

A. Embodiment:
A-1. Constitution:
(Structure of fuel cell stack 100)
FIG. 1 is a perspective view showing an external configuration of the fuel cell stack 100 according to the present embodiment, and FIG. 2 is an XZ of the fuel cell stack 100 at the position II-II of FIG. 1 (and FIGS. 6 to 8 described later). It is explanatory drawing which shows the cross-sectional structure, and FIG. 3 is an explanatory view which shows the YZ cross-sectional structure of the fuel cell stack 100 at the position III-III of FIG. 1 (and FIGS. Each figure shows XYZ axes that are orthogonal to each other to identify 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 actually installed in a direction different from such an orientation. May be done. The same applies to FIGS. 4 and later.

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

A plurality of holes (eight in this embodiment) penetrating in the vertical direction are formed on the peripheral edge of each layer (power generation unit 102, end plates 104, 106) constituting the fuel cell stack 100 in the vertical direction. The holes formed in each layer and corresponding to each other communicate with each other in the vertical direction to form a communication hole 108 extending in the vertical direction from one end plate 104 to the other end plate 106. In the following description, the holes formed in each layer of the fuel cell stack 100 to form the communication holes 108 may also be referred to as communication holes 108.

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 forming the upper end of the fuel cell stack 100, and the bolt. An insulating sheet 26 is interposed between the nut 24 fitted on the other side (lower side) of the 22 and the lower surface of the end plate 106 forming the lower end of the fuel cell stack 100. However, in the place where the gas passage member 27 described later is provided, the insulating sheets arranged on the upper side and the lower side of the gas passage member 27 and the gas passage member 27 between the nut 24 and the surface of the end plate 106, respectively. 26 is intervening. The insulating sheet 26 is made of, for example, a mica sheet, a ceramic fiber sheet, a ceramic dust sheet, a glass sheet, a glass-ceramic composite agent, or the like.

The outer diameter of the shaft portion of each bolt 22 is smaller than the inner diameter of each communication hole 108. Therefore, a space is secured between the outer peripheral surface of the shaft portion of each bolt 22 and the inner peripheral surface of each communication hole 108. As shown in FIGS. 1 and 2, 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-axis direction. In the space formed by the position bolt 22 (bolt 22A) and the communication hole 108 into which the bolt 22A is inserted, the oxidant gas OG is introduced from the outside of the fuel cell stack 100, and the oxidant gas OG is introduced into each of the spaces. It functions as an oxidizer gas introduction manifold 161 which is a gas flow path supplied to the power generation unit 102, and is inside the side opposite to the side (the side on the negative side of the X axis among the two sides parallel to the Y axis). The space formed by the bolt 22 (bolt 22B) located near the point and the communication hole 108 into which the bolt 22B is inserted is an oxidizer off-gas OOG which is a gas discharged from the air chamber 166 of each power generation unit 102. 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.

Further, as shown in FIGS. 1 and 3, the midpoint of one side (the side on the Y-axis positive direction side of the two sides parallel to the X-axis) on the outer circumference of the fuel cell stack 100 around the Z-axis direction. In the space formed by the bolt 22 (bolt 22D) located in the vicinity and the communication hole 108 into which the bolt 22D is inserted, the fuel gas FG is introduced from the outside of the fuel cell stack 100, and the fuel gas FG is introduced into each of the spaces. A bolt that functions as a fuel gas introduction manifold 171 to be supplied to the power generation unit 102 and is located near the midpoint of the opposite side (the side on the negative side of the Y axis of the two sides parallel to the X axis). The space formed by the 22 (bolt 22E) and the communication hole 108 into which the bolt 22E is inserted is provided with the fuel off-gas FOG, which is the gas discharged from the fuel chamber 176 of each power generation unit 102, outside the fuel cell stack 100. It functions as a fuel gas discharge manifold 172 that discharges to. In the present embodiment, for example, a hydrogen-rich gas obtained by reforming city gas is used as the fuel gas FG. The fuel gas introduction manifold 171 corresponds to the supply side manifold in the claims, and the fuel gas discharge manifold 172 corresponds to the discharge side manifold in the claims.

The fuel cell stack 100 is provided with four gas passage members 27. Each gas passage member 27 has a hollow tubular main body 28 and a hollow tubular branch 29 branched from the side surface of the main body 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 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 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 28 of the gas passage member 27 arranged at the position of the bolt 22D forming the fuel gas introduction manifold 171 communicates with the fuel gas introduction manifold 171 and fuel gas. The hole of the main body 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 held in a pressed state by a pair of end plates 104 and 106. The upper end plate 104 functions as a positive output terminal of the fuel cell stack 100, and the lower end plate 106 functions as a negative output terminal of the fuel cell stack 100.

(Structure of power generation unit 102)
FIG. 4 is an explanatory view showing an XZ cross-sectional configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. 2, and FIG. 5 is an explanatory view showing an XZ cross-sectional configuration at the same position as the cross section shown in FIG. It is explanatory drawing which shows the YZ cross-sectional structure of two power generation units 102. Further, FIG. 6 is an explanatory view showing the XY cross-sectional configuration of the power generation unit 102 at the position of VI-VI in FIG. 4, and FIG. 7 is an explanatory view showing the XY cross-sectional configuration of the power generation unit 102 at the position of VII-VII in FIG. FIG. 8 is an explanatory diagram showing an XY cross-sectional configuration of the power generation unit 102 at the position of VIII-VIII in FIG.

As shown in FIGS. 4 and 5, the power generation unit 102 includes a fuel cell single cell (hereinafter referred to as “single cell”) 110, a separator 120, an air electrode side frame 130, a fuel electrode side frame 140, and fuel. It includes a polar collector 144 and a pair of interconnectors 150 that form the top and bottom layers of the power generation unit 102. Holes corresponding to the communication holes 108 into which the bolts 22 described above are inserted are formed on the peripheral edges of the separator 120, the air pole side frame 130, the fuel pole side frame 140, and the interconnector 150 around the Z-axis direction.

As shown in FIG. 6, the interconnector 150 is a conductive member having a substantially rectangular outer shape in the Z-axis direction, 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 the end plate 106, the power generation unit 102 located at the bottom of the fuel cell stack 100 does not have the lower interconnector 150 (see FIGS. 2 and 3).

As shown in FIGS. 4 to 7, the portion of the interconnector 150 facing the single cell 110 has a convex portion 152 protruding downward (hereinafter referred to as “air pole side convex portion 152”) and an air pole side. A plurality of combinations with a recess 154 (hereinafter, referred to as "fuel pole side recess 154") which is arranged on the upper side of the convex portion 152 and is recessed on the air pole side convex portion 152 side are formed. Further, a recess 156 (hereinafter referred to as "air pole side recess 156") is formed between two adjacent air pole side convex portions 152, and a convex portion 158 is formed between two adjacent fuel pole side concave portions 154. (Hereinafter, referred to as "fuel electrode side convex portion 158") is formed. That is, the interconnector 150 has a fuel pole side convex portion 158 protruding upward and an air pole side concave portion 156 arranged below the fuel pole side convex portion 158 and recessed toward the fuel pole side convex portion 158. A plurality of combinations of are also formed. The plurality of fuel pole side convex portions 158 formed on the interconnector 150 correspond to the plurality of convex portions within the claims, and the plurality of fuel pole side concave portions 154 formed on the interconnector connector 150 are formed on the plurality of concave portions. Equivalent to.

Each fuel pole side convex portion 158 formed on the lower interconnector 150 of a power generation unit 102 is in direct or indirect contact with the fuel pole side current collector 144 of the power generation unit 102. Further, each air electrode side convex portion 152 of the interconnector 150 is in direct or indirect contact with the air electrode 114 of another power generation unit 102 adjacent to the lower side. Therefore, the interconnector 150 ensures electrical continuity between the power generation units 102. Each fuel pole side recess 154 formed in the lower interconnector 150 of a certain power generation unit 102 constitutes a part of a fuel chamber 176 facing the fuel pole 116 of the power generation unit 102, and a certain power generation unit 102. Each air electrode side recess 156 formed in the upper interconnector 150 in the above constitutes a part of the air chamber 166 facing the air electrode 114 of the power generation unit 102.

As shown in FIG. 6, in the present embodiment, the fuel pole side concave portion 154 and the air pole side convex portion 152 have a length in the X-axis direction in the Y-axis direction (mainly in the fuel chamber 176 described later) in the Z-axis direction. It has an elongated shape that is longer than the length in the second direction, which is the gas flow direction). Further, the fuel pole side concave portion 154 and the air pole side convex portion 152 are arranged in a grid pattern arranged in the X-axis direction and the Y-axis direction in the Z-axis direction.

In the present embodiment, the interconnector 150 is made by pressing a flat metal material to form a plurality of combinations of the air electrode side convex portion 152 and the fuel electrode side concave portion 154, and the fuel electrode side convex portion 158 and the air electrode. Manufactured by forming a plurality of combinations with the side recesses 156. More specifically, the portion between the two adjacent air pole side convex portions 152 formed by the press working becomes the air pole side concave portion 156, and the portion between the two adjacent fuel pole side concave portions 154 formed by the press working. Is the fuel electrode side convex portion 158. By forming the convex portions and concave portions of the interconnector 150 by press working, the efficiency of the manufacturing process can be improved as compared with the case where other methods such as etching are used.

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 in between. 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 flat plate-shaped member substantially rectangular in the Z-axis direction, and is, for example, YSZ (yttria-stabilized zirconia), ScSZ (scandia-stabilized zirconia), SDC (samarium-doped ceria), GDC (gadolinium-doped ceria). , Is formed of solid oxides such as perovskite-type oxides. 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 air electrode 114 is a substantially rectangular flat plate-shaped member smaller than the electrolyte layer 112 in the Z-axis direction, and is, for example, a perovskite-type oxide (for example, LSCF (lanternstrontium cobalt iron oxide), LSM (lanternstrontium manganese oxide)). , LNF (Lantern Nickel Iron)). The fuel electrode 116 is a substantially rectangular flat plate-shaped member having substantially the same size as the electrolyte layer 112 in the Z direction, and is formed of, for example, Ni (nickel), a cermet composed of Ni and ceramic particles, a Ni-based alloy, or the like. ing. The fuel electrode 116 corresponds to a specific electrode in the claims.

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 made of metal, for example. 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.

As shown in FIG. 7, the air electrode side frame 130 is a frame-shaped member in which a substantially rectangular gas chamber 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 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. .. The air electrode side frame 130 electrically insulates between the pair of interconnectors 150 included in the power generation unit 102.

The gas chamber hole 131 of the air electrode side frame 130 is a hole forming the air chamber 166 facing the air electrode 114. The gas chamber hole 131 has a first inner surface IP1 and a second inner surface IP2 facing each other in the X-axis direction. Further, the air electrode side frame 130 has an oxidant gas supply communication flow path 132 that communicates with the communication hole 108 constituting the oxidant gas introduction manifold 161 and opens to the first inner surface IP1 of the gas chamber hole 131. An oxidant gas discharge communication flow path 133 that communicates with the communication hole 108 constituting the oxidant gas discharge manifold 162 and opens to the second inner surface IP2 of the gas chamber hole 131 is formed. In the present embodiment, the air electrode side frame 130 is formed with three oxidant gas supply communication channels 132 and three oxidant gas discharge communication channels 133.

As shown in FIG. 8, the fuel electrode side frame 140 is a frame-shaped member in which a substantially rectangular gas chamber hole 141 penetrating in the vertical direction is formed near the center, and is formed of, for example, metal. 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.

The gas chamber hole 141 of the fuel electrode side frame 140 is a hole constituting the fuel chamber 176 facing the fuel electrode 116. The gas chamber hole 141 has a third inner surface IP3 and a fourth inner surface IP4 facing each other in the Y-axis direction. Further, the fuel electrode side frame 140 has a fuel gas supply communication flow path 142 that communicates with the communication hole 108 constituting the fuel gas introduction manifold 171 and opens to the third inner surface IP3 of the gas chamber hole 141, and the fuel gas. A fuel gas discharge communication flow path 143 that communicates with the communication hole 108 constituting the discharge manifold 172 and opens to the fourth inner surface IP4 of the gas chamber hole 141 is formed. In the present embodiment, the fuel electrode side frame 140 is formed with three fuel gas supply communication flow paths 142 and three fuel gas discharge communication flow paths 143.

The fuel electrode side frame 140 corresponds to the frame member in the claims, and the gas chamber hole 141 corresponds to the gas chamber hole in the claims. Further, among the communication holes 108 formed in the fuel electrode side frame 140, the communication holes 108 constituting the fuel gas introduction manifold 171 correspond to the holes for the supply side manifold in the claims, and the fuel gas discharge manifold 172 is provided. The constituent communication holes 108 correspond to the discharge-side manifold holes in the claims. Further, the fuel gas supply communication flow path 142 formed in the fuel electrode side frame 140 corresponds to the supply side communication flow path in the claims, and the fuel gas discharge communication flow path 143 is the discharge side in the claims. Corresponds to the communication flow path.

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 nickel alloy. , Stainless steel, etc. As shown in the partially enlarged view in FIG. 8, the fuel electrode side current collector 144 is manufactured by making a cut in a substantially rectangular flat plate member (for example, nickel foil) and processing the plurality of rectangular portions so as to bend them up. Rectangle. Each of the bent rectangular portions becomes the electrode facing portion 145, and the flat plate portion in which the hole OP other than the bent portion is opened becomes the interconnector facing portion 146, and the electrode facing portion 145 and the interconnector facing portion 146 are formed. The connecting portion becomes the connecting portion 147. In the partially enlarged view of FIG. 8, in order to show the manufacturing method of the fuel electrode side current collector 144, a state before the bending raising process is completed is shown for a part of the rectangular portions. 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. The fuel electrode side current collector 144 further includes a spacer 149 arranged between the electrode facing portion 145 and the interconnector facing portion 146. The spacer 149 is formed of, for example, mica. Due to the presence of the spacer 149, the electrode facing portion 145 and the like follow 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) via the fuel pole side current collector 144 The electrical connection with 106) is well maintained. The fuel electrode side current collector 144 corresponds to a current collector within the scope of the claims.

As shown in FIGS. 4 and 5, the surface of the interconnector 150 on the air electrode 114 side is covered with a conductive coat 136. Coating 136, for example, spinel-type oxides _{(e.g., MnCo 2 O 4, ZnMn 2} O 4, CuMn 2 O 4 , etc.) are formed by. The formation of the coat 136 on the surface of the interconnector 150 is performed by well-known methods such as spray coating, inkjet printing, spin coating, dip coating, plating, sputtering, and thermal spraying. The presence of the coat 136 suppresses the occurrence of a phenomenon called "Cr diffusion" in which Cr is released from the surface of the interconnector 150 and diffuses, and the interconnector 150 is abnormally oxidized due to Cr deficiency, or the diffused Cr is an air electrode. It is possible to suppress the occurrence of a phenomenon called "Cr poisoning of the air electrode" that adheres to the surface of the 114 and reduces the electrode reaction rate at the air electrode 114.

The air electrode 114 and the interconnector 150 (more specifically, each air electrode side convex portion 152 of the interconnector 150) are bonded by a conductive bonding layer 138. The bonding layer 138 is formed of, for example, a spinel-type oxide (for example, Mn _1.5 Co _1.5 O ₄ or Mn Co ₂ O ₄ , ZnCo ₂ O ₄ , ZnMn ₂ O ₄ , ZnMn CoO ₄ , Cumn ₂ O ₄ ). Has been done. The bonding layer 138 electrically connects the air electrode 114 and the interconnector 150. Earlier, it was explained that the interconnector 150 is in contact with the surface of the air electrode 114, but in the present embodiment, a bonding layer 138 is formed between the interconnector 150 covered with the coat 136 and the air electrode 114. It is intervening.

A-2. Operation of fuel cell stack 100:
As shown in FIGS. 2 and 4, the oxidant gas OG is supplied via a gas pipe (not shown) connected to the branch portion 29 of the gas passage member 27 provided at the position of the oxidant gas introduction manifold 161. Then, the oxidant gas OG is supplied to the oxidant gas introduction manifold 161 through the holes of the branch portion 29 and the main body portion 28 of the gas passage member 27, and the oxidizer gas introduction manifold 161 oxidizes each power generation unit 102. It is supplied to the air chamber 166 via the agent gas supply communication flow path 132. Further, as shown in FIGS. 3 and 5, the fuel gas FG is supplied via a gas pipe (not shown) connected to the branch portion 29 of the gas passage member 27 provided at the position of the fuel gas introduction manifold 171. Then, the fuel gas FG is supplied to the fuel gas introduction manifold 171 through the holes of the branch portion 29 and the main body portion 28 of the gas passage member 27, and the fuel gas supply communication of each power generation unit 102 is performed from the fuel gas introduction manifold 171. It is supplied to the fuel chamber 176 via the flow path 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, power is generated by the electrochemical reaction of the oxidant gas OG and the fuel gas FG in the single cell 110. Will be. This power generation reaction is an exothermic reaction. In each power generation unit 102, the air pole 114 of the single cell 110 is electrically connected to one interconnector 150 via the junction layer 138, and the fuel pole 116 is connected to the other interconnector via the fuel pole side current collector 144. It is electrically connected to 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 electricity at a relatively high temperature (for example, 700 ° C. to 1000 ° C.), the fuel cell stack 100 is a heater (for example, until the high temperature can be maintained by the heat generated by the power generation after the start-up. (Not shown) may be heated.

As shown in FIGS. 2 and 4, the oxidant off-gas OOG discharged from the air chamber 166 of each power generation unit 102 is discharged to the oxidant gas discharge manifold 162 via the oxidant gas discharge communication flow path 133, and further. The fuel cell stack passes through the holes of the main body 28 and the branch 29 of the gas passage member 27 provided at the position of the oxidant gas discharge manifold 162, and via the gas pipe (not shown) connected to the branch 29. It is discharged to the outside of 100. Further, as shown in FIGS. 3 and 5, the fuel off-gas FOG discharged from the fuel chamber 176 of each power generation unit 102 is discharged to the fuel gas discharge manifold 172 via the fuel gas discharge communication flow path 143, and further fuel. The outside of the fuel cell stack 100 via the holes of the main body 28 and the branch 29 of the gas passage member 27 provided at the position of the gas discharge manifold 172, and the gas pipe (not shown) connected to the branch 29. Is discharged to.

As shown in FIG. 8, in each power generation unit 102 constituting the fuel cell stack 100 of the present embodiment, the main flow direction of the fuel gas FG in the fuel chamber 176 is generally from the Y-axis positive direction side to the Y-axis negative direction. The direction is toward the side. The main flow direction of the fuel gas FG in the fuel chamber 176 is, for example, from the midpoint MP1 of the opening of the gas chamber hole 141 of the gas chamber hole 141 of the fuel gas supply communication flow path 142 to the third inner surface IP3 to the fuel gas discharge communication flow path 143. It can be specified as the direction toward the midpoint MP2 of the opening to the fourth inner surface IP4 of the gas chamber hole 141. Here, in the present embodiment, a plurality (three) fuel gas supply communication flow paths 142 are formed in the fuel electrode side frame 140, but in such a case, the fuel gas supply communication flow path 142 described above The midpoint MP1 of the opening of the gas chamber hole 141 to the third inner surface IP3 is an opening composed of an opening of the gas chamber hole 141 of the plurality of fuel gas supply communication channels 142 to the third inner surface IP3. It means the midpoint of the line connecting both end points (EP11, EP12) of the group. Similarly, in the present embodiment, a plurality (three) fuel gas discharge communication flow paths 143 are formed in the fuel electrode side frame 140, but in such a case, the fuel gas discharge communication flow path 143 described above The midpoint MP2 of the opening of the gas chamber hole 141 to the fourth inner surface IP4 is an opening composed of an opening of the gas chamber hole 141 of the plurality of fuel gas discharge communication flow paths 143 to the fourth inner surface IP4. It means the midpoint of the line connecting both end points (EP21, EP22) of the group.

Further, in the present embodiment, the third inner surface IP3 of the gas chamber hole 141 in which the fuel gas supply communication flow path 142 opens in the Z-axis direction has a substantially linear portion and the fuel gas discharge communication. The fourth inner surface IP4 of the gas chamber hole 141 through which the flow path 143 opens has a substantially linear portion substantially parallel to the substantially linear portion of the third inner surface IP3. Therefore, the main flow directions of the fuel gas FG in the fuel chamber 176 are, for example, a substantially linear portion of the third inner surface IP3 of the gas chamber hole 141 and the fourth of the gas chamber hole 141 in the Z-axis direction. It can also be specified as the direction in which the substantially linear portion of the inner surface IP4 faces. That is, the main flow direction of the fuel gas FG in the fuel chamber 176 is abbreviated in the third inner surface IP3 in which the fuel gas supply communication flow path 142 opens in the inner peripheral surface of the gas chamber hole 141 in the Z-axis direction. From the linear portion, the substantially linear portion on the fourth inner surface IP4 through which the fuel gas discharge communication flow path 143 opens, and toward the substantially linear portion substantially parallel to the substantially linear portion on the third inner surface IP3. It can be said that it is a direction.

The main flow direction of the fuel gas FG in the fuel chamber 176 specified by each of the above methods corresponds to the second direction in the claims.

A-3. Detailed configuration of interconnector 150 and fuel electrode side current collector 144:
FIG. 9 is an explanatory diagram showing a detailed configuration of the interconnector 150 and the fuel electrode side current collector 144. FIG. 9 shows an enlarged XZ cross-sectional configuration of the power generation unit 102 in the X1 part of FIG. As described above, since the main flow direction of the fuel gas FG in the fuel chamber 176 is the Y-axis direction, the XZ cross section shown in FIG. 9 is orthogonal to the main flow direction and the air electrode in the single cell 110. The cross section is parallel to the facing direction (Z-axis direction) of 114 and the fuel electrode 116. The XZ cross section shown in FIG. 9 corresponds to a specific cross section within the scope of claims.

As described above, the fuel electrode side current collector 144 includes an electrode facing portion 145, an interconnector facing portion 146, a connecting portion 147, and a spacer 149. In the following description, one electrode facing portion 145 in the fuel electrode side current collector 144, a connecting portion 147 connected to the electrode facing portion 145, and an interconnector facing portion overlapping the electrode facing portion 145 in the Z-axis direction. The portion of the 146 and the spacer 149 are collectively referred to as a current collector 148. The fuel electrode side current collector 144 has a plurality of current collectors 148. Each of the plurality of current collectors 148 conducts to the surface of the fuel electrode 116. Further, the space between the current collector 148 and the current collector 148 functions as a gas flow path space 210 facing the fuel electrode 116. That is, the plurality of current collectors 148 are lined up with the gas flow path space 210 facing the fuel electrode 116 interposed therebetween. The current collector 148 is configured so as not to have gas permeability. Here, the configuration having no gas permeability means a configuration that does not substantially permeate the gas. In other words, it is configured to change the flow of the gas when it comes into contact with the gas. For example, when the electrode facing portion 145 constituting the current collecting portion 148, the connecting portion 147, and the interconnector facing portion 146 are formed of nickel foil, and the spacer 149 forming the current collecting portion 148 is formed of mica, the current collecting portion 148 is formed. Has a configuration that does not have gas permeability. Since the current collector 148 is configured so as not to have gas permeability, the flow of the fuel gas FG between the two flow paths sandwiching the current collector 148 is restricted in the fuel chamber 176. The average density of the collector part 148 is, for ^{example, 1g / cm 3 ~10g / cm 3} . Further, a cross section (for example, Z-axis direction) orthogonal to the main flow direction (Y-axis direction) of the fuel gas FG in the fuel chamber 176 and parallel to the facing direction (Z-axis direction) between the air pole 114 and the fuel pole 116 in the single cell 110. (XZ cross section shown in FIG. 9), it overlaps with the electrode facing portion 145 in the Z-axis direction, and is located between the surface of the fuel pole 116 and the position of the apex of the fuel pole side convex portion 158 of the interconnector 150. The ratio of the cross-sectional area of the current collecting unit 148 to the cross-sectional area of the portion (S1 part in FIG. 9) is, for example, 30% or more.

In the power generation unit 102 of the present embodiment, in the XZ cross section shown in FIG. 9, the fuel pole side current collector 144 is collected between the fuel pole side convex portion 158 and the fuel pole 116 formed on the interconnector 150. The current collector 148 is not located, and there is a gas flow path space 210 formed between the current collector 148 and the current collector 148. The existence of the gas flow path space 210 between the fuel pole side convex portion 158 and the fuel pole 116 does not necessarily mean that the entire width direction (X-axis direction) of the fuel pole side convex portion 158 is between the fuel pole 116. The gas flow path space 210 is not limited to the form in which the gas flow path space 210 exists, and the gas flow path space 210 exists between a part of the fuel pole side convex portion 158 in the width direction and the fuel pole 116, and the width of the fuel pole side convex portion 158. Includes a form in which the current collector 148 is located between the remaining portion of the direction and the fuel pole 116.

Further, in the power generation unit 102 of the present embodiment, in the XZ cross section shown in FIG. 9, the gas flow path space 210 existing between the fuel pole side convex portion 158 and the fuel pole 116 of the interconnector 150 is the fuel. Space 220 in the fuel pole side recess 154 adjacent to one side of the pole side convex portion 158 (for example, the X-axis positive direction side) and the other side of the fuel pole side convex portion 158 (for example, the X-axis negative direction side). It communicates with the space 220 in the fuel electrode side recess 154 adjacent to the above. That is, on both sides of the fuel pole side convex portion 158 in the width direction (X-axis direction), in the gas flow path space 210 and the fuel pole side concave portion 154 existing between the fuel pole side convex portion 158 and the fuel pole 116. There is a gap 230 that communicates with the space 220. The space 220 in the fuel pole side recess 154 adjacent to one side (for example, the X-axis positive direction side) of a certain fuel pole side convex portion 158 is a first space in the first recess within the scope of claims. The space 220 in the fuel electrode side recess 154 corresponding to the fuel electrode side convex portion 158 and adjacent to the other side (for example, the X-axis positive / negative direction side) is the second recess in the second recess within the scope of the claims. Corresponds to the space of.

Further, in the power generation unit 102 of the present embodiment, in the XZ cross section shown in FIG. 9, the gas flow path space 210 existing between the fuel pole side convex portion 158 and the fuel pole 116 of the interconnector 150 is the fuel. It communicates with another gas flow path space 210 via a space 220 in the fuel pole side recess 154 adjacent to one side (for example, the X-axis positive direction side) of the pole side convex portion 158. Further, in the power generation unit 102 of the present embodiment, in the XZ cross section shown in FIG. 9, the fuel pole side concave portion adjacent to one side (for example, the X-axis positive direction side) of the fuel pole side convex portion 158 of the interconnector 150. 154 faces a plurality of (specifically, three) current collectors 148 in the Z-axis direction. Therefore, in the power generation unit 102 of the present embodiment, in the XZ cross section shown in FIG. 9, the gas flow path space 210 existing between the fuel pole side convex portion 158 and the fuel pole side 116 is the fuel pole side convex portion. The space 220 in the fuel electrode side recess 154 adjacent to the 158 communicates with the two gas flow path spaces 210 sandwiched between the three current collectors 148. In the power generation unit 102 of the present embodiment, the gas flow path space 210 existing between the fuel pole side convex portion 158 and the fuel pole 116 is inside the fuel pole side concave portion 154 adjacent to the fuel pole side convex portion 158. It communicates with two gas flow path spaces 210 sandwiched between the three current collecting portions 148 via the space 220 of the above, and further, another fuel pole side convex portion 158 adjacent to the fuel pole side concave portion 154. It communicates with another gas flow path space 210 existing between the fuel electrode 116 and the fuel electrode 116.

In the power generation unit 102 of the present embodiment, in the XZ cross section shown in FIG. 9, other fuel pole side convex portions 158 (not shown) have the same configuration as above (for example, fuel pole side convex portion 158). The gas flow path space 210 existing between the fuel electrode 116 and the fuel electrode 116 communicates with the space 220 in the fuel electrode side recess 154). Further, as described above, the fuel pole side recesses 154 of the interconnector 150 are arranged in a grid pattern arranged in the X-axis direction and the Y-axis direction in the Z-axis direction (see FIG. 6). In the power generation unit 102 of the present embodiment, another XZ cross section different from the XZ cross section shown in FIG. 9 (another fuel pole side recess 154 different from the fuel pole side recess 154 through which the XZ cross section shown in FIG. 9 passes). In any XZ cross section passing through the above, the gas flow path space 210 existing between the fuel pole side convex portion 158 and the fuel pole side 116 is the space 220 in the fuel pole side concave portion 154. The configuration that communicates with) is adopted. These XZ cross sections also correspond to specific cross sections within the scope of the claims.

A-4. Effect of this embodiment:
As described above, each power generation unit 102 constituting the fuel cell stack 100 of the present embodiment includes a single cell 110, a fuel pole side frame 140, an interconnector 150, and a fuel pole side current collector 144. .. The single cell 110 includes an electrolyte layer 112, and an air pole 114 and a fuel pole 116 that face each other in the Z-axis direction (first direction) with the electrolyte layer 112 interposed therebetween. In the fuel electrode side frame 140, a gas chamber hole 141 constituting a fuel chamber 176 facing the fuel electrode 116 and a communication hole 108 constituting a fuel gas introduction manifold 171 through which the fuel gas FG supplied to the fuel chamber 176 passes. And the communication hole 108 constituting the fuel gas discharge manifold 172 through which the fuel off-gas FOG discharged from the fuel chamber 176 passes, and the communication hole 108 constituting the fuel gas introduction manifold 171, and the third gas chamber hole 141. The fuel gas supply communication flow path 142 that opens to the inner surface IP3 of the gas chamber and the communication hole 108 that constitutes the fuel gas discharge manifold 172, and the fuel gas discharge communication flow path that opens to the fourth inner surface IP4 of the gas chamber hole 141. 143 and are formed. A plurality of fuel pole side convex portions 158 and a plurality of fuel pole side concave portions 154 are formed on the surface of the interconnector 150 on the side facing the fuel pole 116. The fuel pole side current collector 144 is a conductive member that electrically connects the fuel pole 116 and the interconnector 150, and is a gas flow that conducts to the surface of the fuel pole 116 and faces the fuel pole 116, respectively. It has a plurality of current collectors 148 arranged side by side with the road space 210 in between. Further, in the power generation unit 102 of the present embodiment, the midpoint MP1 and the fuel gas discharge communication flow path 143 of the opening to the third inner surface IP3 of the gas chamber hole 141 of the fuel gas supply communication flow path 142 in the Z-axis direction A specific cross section that is orthogonal to the direction (Y-axis direction, second direction) connecting the midpoint MP2 of the opening of the gas chamber hole 141 to the fourth inner surface IP4 and parallel to the Z-axis direction. (For example, in the XZ cross section shown in FIG. 9), the fuel pole side convex portion 158 and the fuel pole 116 formed on the interconnector 150 are adjacent to one side of the fuel pole side convex portion 158. There is a gas flow path space 210 communicating with the space 220 in the fuel electrode side recess 154.

As described above, in the power generation unit 102 of the present embodiment, the interconnector 150 has a specific cross section (for example, the XZ cross section shown in FIG. 9) orthogonal to the main gas flow direction (the second direction) in the fuel chamber 176. A gas flow path space 210 sandwiched between the current collector 148 and the current collector 148 of the fuel electrode side current collector 144 is located between the fuel pole side convex portion 158 and the fuel pole 116, and the gas flow path space 210 is located. The gas flow path space 210 communicates with the space 220 in the fuel pole side recess 154 adjacent to the fuel pole side convex portion 158. Therefore, according to the power generation unit 102 of the present embodiment, the fuel gas FG supplied to the fuel chamber 176 is satisfactorily oriented in a direction substantially orthogonal to the main gas flow direction in the fuel chamber 176 (for example, the X-axis direction). It can be diffused, and as a result, the power generation performance can be improved.

Further, in the power generation unit 102 of the present embodiment, in the specific cross section, between the fuel pole side convex portion 158 and the fuel pole 116 formed on the interconnector 150, one side of the fuel pole side convex portion 158 is formed. There is a gas flow path space 210 communicating with the space 220 in the adjacent fuel pole side recess 154 and the space 220 in the adjacent fuel pole side recess 154 on the other side of the fuel pole side convex portion 158. As described above, in the power generation unit 102 of the present embodiment, in the specific cross section orthogonal to the main gas flow direction in the fuel chamber 176, the fuel pole side is located between the fuel pole side convex portion 158 and the fuel pole 116 of the interconnector 150. The gas flow path space 210 sandwiched between the current collection unit 148 and the current collection unit 148 of the current collector 144 is located, and the gas flow path space 210 is adjacent to both sides of the fuel pole side convex portion 158. It communicates with the space 220 in the two fuel pole side recesses 154. Therefore, according to the power generation unit 102 of the present embodiment, the fuel gas FG supplied to the fuel chamber 176 can be more satisfactorily diffused in a direction substantially orthogonal to the main gas flow direction in the fuel chamber 176. As a result, the power generation performance can be effectively improved.

Further, in the power generation unit 102 of the present embodiment, in the specific cross section, the gas flow path space 210 located between the fuel pole side convex portion 158 formed on the interconnector 150 and the fuel pole 116 is on the fuel pole side. It communicates with another gas flow path space 210 via a space 220 in the fuel electrode side recess 154 adjacent to one side of the convex portion 158. Therefore, according to the power generation unit 102 of the present embodiment, the fuel gas FG supplied to the fuel chamber 176 can be more satisfactorily diffused in a direction substantially orthogonal to the main gas flow direction in the fuel chamber 176. As a result, the power generation performance can be improved more effectively. In the power generation unit 102 of the present embodiment, the fuel pole side concave portion 154 adjacent to one side of the fuel pole side convex portion 158 faces a plurality of current collectors 148 in the Z-axis direction. Therefore, in the power generation unit 102 of the present embodiment, the gas flow path space 210 located between the fuel pole side convex portion 158 and the fuel pole 116 is passed through the space 220 in the fuel pole side concave portion 154. It communicates with a plurality of other gas flow path spaces 210. Therefore, according to the power generation unit 102 of the present embodiment, the fuel gas FG supplied to the fuel chamber 176 can be diffused extremely well in a direction substantially orthogonal to the main gas flow direction in the fuel chamber 176. As a result, the power generation performance can be improved extremely effectively.

In the power generation unit 102 of the present embodiment, since the current collector 148 of the fuel electrode side current collector 144 does not have gas permeability, the direction is substantially orthogonal to the main gas flow direction in the fuel chamber 176. Deterioration of gas diffusivity tends to be an issue. However, in the power generation unit 102 of the present embodiment, since each of the above configurations is adopted, the fuel gas FG supplied to the fuel chamber 176 is oriented in a direction substantially orthogonal to the main gas flow direction in the fuel chamber 176. It can be diffused well, and as a result, the power generation performance can be improved.

Further, in the power generation unit 102 of the present embodiment, the length of the fuel electrode side recess 154 in the direction orthogonal to the main gas flow direction in the fuel chamber 176 (for example, the X-axis direction) in the Z-axis direction is the fuel chamber 176. It is longer than the length of the fuel electrode side recess 154 in the main gas flow direction (for example, the Y-axis direction) in (see FIG. 6). Therefore, according to the power generation unit 102 of the present embodiment, the fuel gas FG supplied to the fuel chamber 176 is directed to the main gas flow direction in the fuel chamber 176 by utilizing the space 220 in the fuel electrode side recess 154. It can be well diffused in the substantially orthogonal directions, and as a result, the power generation performance can be effectively improved.

Further, in the power generation unit 102 of the present embodiment, in the Z-axis direction view, the plurality of fuel pole side recesses 154 formed in the interconnector 150 are in a direction orthogonal to the main gas flow direction in the fuel chamber 176 (for example, the X-axis). The above configuration is arranged in an arbitrary plurality of specific cross sections (XZ cross sections) that are arranged in a grid pattern that is lined up in the gas flow direction (for example, the Y-axis direction) and passes through the fuel electrode side recesses 154 that are different from each other. It has been adopted. Therefore, according to the power generation unit 102 of the present embodiment, the fuel gas FG supplied to the fuel chamber 176 is set with respect to the main gas flow direction in the fuel chamber 176 at a plurality of positions arranged in the main gas flow direction in the fuel chamber 176. It can be well diffused in the directions substantially orthogonal to each other, and as a result, the power generation performance can be effectively improved.

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

The configuration of the single cell 110, the power generation unit 102, or the fuel cell stack 100 in the above embodiment is merely an example and can be variously modified. For example, in the above embodiment, a plurality of fuel pole side convex portions 158 and a plurality of fuel pole side concave portions 154 are formed on the surface of the interconnector 150 on the side facing the fuel pole 116, and the air of the interconnector 150 is formed. A plurality of air pole side convex portions 152 and a plurality of air pole side concave portions 156 are formed on the surface on the side facing the pole 114, but the convex portion is formed on the surface of the interconnector 150 on the side facing the air pole 114. And may not be provided with recesses (ie, have a substantially flat shape).

Further, in the above embodiment, the current collector 148 of the fuel electrode side current collector 144 is, for example, an electrode facing portion 145 made of metal, an interconnector facing portion 146, a connecting portion 147, and an electrode facing portion 145 and an interconnector. Although it is arranged between the facing portion 146 and is composed of, for example, a spacer 149 formed of mica, the shape and material of the current collecting portion 148 can be variously deformed. For example, the current collector 148 may be composed of a single member that contacts both the fuel electrode 116 and the interconnector 150.

Further, in the above embodiment, in one specific cross section (for example, the XZ cross section shown in FIG. 9), all the fuel pole side convex portions 158 have the above-described configuration (for example, the fuel pole side convex portion 158 and the fuel pole 116). The gas flow path space 210 existing between the two and the fuel passage space 210 communicates with the space 220 in the fuel electrode side recess 154), but it is not always necessary to have such a structure. It suffices that the above-described configuration is adopted for at least one fuel pole side convex portion 158 in the cross section.

Further, in the above embodiment, the gas flow path space existing between the above-described configuration (for example, the fuel pole side convex portion 158 and the fuel pole 116) in any plurality of specific cross sections passing through the fuel pole side concave portions 154 different from each other. The structure in which 210 communicates with the space 220 in the fuel electrode side recess 154) is adopted, but it is not always necessary to have such a structure, and the above-mentioned structure is adopted in at least one specific cross section. Just do it. From the viewpoint of satisfactorily diffusing the fuel gas FG in a direction substantially orthogonal to the main gas flow direction in the fuel chamber 176, among any plurality of specific cross sections passing through the fuel pole side recesses 154 different from each other described above, At least, a specific cross section located on the upstream side in the main gas flow direction in the fuel chamber 176 (for example, a specific cross section overlapping the portion of the single cell 110 closest to the gas upstream side when the single cell 110 is divided into three equal parts in the gas flow direction). It is preferable that the above-described configuration is adopted in the cross section).

Further, the configuration described in the above embodiment (for example, the gas flow path space 210 existing between the fuel pole side convex portion 158 and the fuel pole 116 is communicated with the space 220 in the fuel pole side concave portion 154). ) May be adopted in all the power generation units 102 included in the fuel cell stack 100, or may be adopted only in some power generation units 102 included in the fuel cell stack 100.

Further, in the above embodiment, regarding the relationship between the interconnector 150 and the fuel pole side current collector 144 arranged between the interconnector 150 and the fuel pole 116, the above configuration (for example, the fuel pole side convex portion 158) The gas flow path space 210 existing between the fuel electrode 116 and the fuel electrode 116 communicates with the space 220 in the fuel electrode side recess 154), but instead of the fuel electrode 116, the air electrode 114 side A similar configuration may be adopted. That is, for example, a conductive current collector that electrically connects the air electrode 114 and the interconnector 150 is arranged, and each of the current collectors conducts to the surface of the air electrode 114 and is conductive. For the gas chamber of the main gas flow direction in the air chamber 166 (for the gas chamber of the oxidant gas supply communication flow path 132 in the Z-axis direction), which has a plurality of current collectors arranged across the gas flow path space facing the air electrode 114. (Direction connecting the midpoint of the opening of the hole 131 to the first inner surface IP1 and the midpoint of the opening of the gas chamber hole 131 for the gas chamber of the oxidizing agent gas discharge communication flow path 133 to the second inner surface IP2). In addition, in a specific cross section which is at least one cross section parallel to the Z-axis direction, a gas flow path space exists between at least one air pole side convex portion 152 formed on the interconnector 150 and the air pole 114. A configuration may be adopted in which the gas flow path space communicates with the space in the air electrode side recess 156 adjacent to one side of the air electrode side convex portion 152. According to such a configuration, the oxidant gas OG supplied to the air chamber 166 can be satisfactorily diffused in a direction substantially orthogonal to the main gas flow direction in the air chamber 166, and as a result, the power generation performance. Can be improved.

Further, in the above embodiment, the surface of the interconnector 150 on the air electrode 114 side is covered with the coat 136, but instead of the surface on the air electrode 114 side or together with the surface on the air electrode 114 side, the interconnector The surface of the 150 on the side of the fuel pole 116 may be covered with a coat (for example, a nickel coat). Further, neither surface of the interconnector 150 may be covered with a coat. Further, in the above embodiment, the fuel pole side frame 140 is formed with the three fuel gas supply communication flow paths 142 and the three fuel gas discharge communication flow paths 143, but the fuel formed on the fuel pole side frame 140 is formed. The number of the gas supply communication flow path 142 and the fuel gas discharge communication flow path 143 may be two or less, or four or more.

Further, in the above embodiment, the number of power generation units 102 included in the fuel cell stack 100 is only 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. Further, in the above embodiment, the space between the outer peripheral surface of the shaft portion of each bolt 22 and the inner peripheral surface of each communication hole 108 is used as each manifold, but instead of this, the shaft of each bolt 22 is used. Axial holes may be formed in the portion, and the holes may be used as each manifold. Further, each manifold may be provided separately from each communication hole 108 into which each bolt 22 is inserted.

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 a constituent unit of a solid oxide fuel cell (SOEC) that generates hydrogen by utilizing it, 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, for example, as described in 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, the power generation unit 102 may be read as an electrolytic cell unit, and the single cell 110 may be read as an electrolytic single cell. However, 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 communication 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 to the outside of the electrolytic cell stack through the communication hole 108. Even in the electrolytic cell unit and the electrolytic cell stack having such a configuration, the performance can be improved by improving the gas diffusibility by adopting the same configuration as that of the above embodiment.

Further, in the above embodiment, the solid oxide fuel cell (SOFC) has been described as an example, but the present invention has a polymer electrolyte fuel cell (PEFC), a phosphoric acid fuel cell (PAFC), and a molten carbonate fuel cell. It is also applicable to other types of fuel cells (or electrolytic cells) such as fuel cells (MCFCs).

22: Bolt 24: Nut 26: Insulation sheet 27: Gas passage member 28: Main body 29: Branch 100: Fuel cell stack 102: Fuel cell power generation unit 104: End plate 106: End plate 108: Communication hole 110: Fuel cell Single cell 112: Electrolyte layer 114: Air pole 116: Fuel pole 120: Separator 121: Hole 124: Joint 130: Air pole side frame 131: Gas chamber hole 132: Oxidizing agent gas supply communication flow path 133: Oxidating agent gas Discharge communication flow path 136: Coat 138: Joint layer 140: Fuel pole side frame 141: Gas chamber hole 142: Fuel gas supply communication flow path 143: Fuel gas discharge communication flow path 144: Fuel pole side current collector 145: Electrode Facing part 146: Interconnector Facing part 147: Connecting part 148: Current collecting part 149: Spacer 150: Interconnector 152: Air pole side convex part 154: Fuel pole side concave part 156: Air pole side concave part 158: Fuel pole side convex part 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 210: Gas flow path space 220: Space 230: Gap

Claims (9)

An electrochemical reaction single cell containing an electrolyte layer and an air electrode and a fuel electrode facing each other in a first direction across the electrolyte layer.
A gas chamber hole forming a gas chamber facing a specific electrode, which is one of the fuel electrode and the air electrode, and a supply side manifold hole forming a supply side manifold through which gas supplied to the gas chamber passes. , The supply side communication flow that communicates with the discharge side manifold hole constituting the discharge side manifold through which the gas discharged from the gas chamber passes and the supply side manifold hole and opens to the inner peripheral surface of the gas chamber hole. A frame member formed with a path and a discharge-side communication flow path that communicates with the discharge-side manifold hole and opens on the inner peripheral surface of the gas chamber hole.
A conductive interconnector in which a plurality of convex portions and a plurality of concave portions are formed on the surface of the side facing the specific electrode.
Conductive current collectors that electrically connect the specific electrode and the interconnector, which are electrically connected to the surface of the specific electrode and lined up with a gas flow path space facing the specific electrode. However, with a current collector that has multiple current collectors,
In the electrochemical reaction unit with
In the first directional view, the middle point of the opening of the supply side communication flow path to the inner peripheral surface of the gas chamber hole and the opening of the discharge side communication flow path to the inner peripheral surface of the gas chamber hole. In a specific cross section which is at least one cross section orthogonal to the second direction connecting the midpoint and parallel to the first direction, the specific convex which is at least one convex portion formed on the interconnector. Between the portion and the specific electrode, there is the gas flow path space that communicates with the first space in the first recess that is adjacent to one side of the specific convex portion. Chemical reaction unit. In the electrochemical reaction unit according to claim 1,
In the specific cross section, between the specific convex portion and the specific electrode, the first space in the first concave portion adjacent to one side of the specific convex portion and the other side of the specific convex portion. An electrochemical reaction unit, characterized in that there is a second space in the second recess adjacent to and the gas flow path space communicating with the second space. In the electrochemical reaction unit according to claim 1 or 2.
In the specific cross section, the gas flow path space located between the specific convex portion and the specific electrode is connected to another gas flow path space via the first space in the first concave portion. An electrochemical reaction unit characterized by communication. In the electrochemical reaction unit according to claim 3,
An electrochemical reaction unit, characterized in that, in the specific cross section, the first recess faces the plurality of current collectors in the first direction. In the electrochemical reaction unit according to any one of claims 1 to 4.
A plurality of the current collectors of the current collector are electrochemical reaction units, characterized in that they do not have gas permeability. In the electrochemical reaction unit according to any one of claims 1 to 5.
In the first directional view, the length of the first recess in the direction orthogonal to the second direction is longer than the length of the first recess in the second direction. Chemical reaction unit. In the electrochemical reaction unit according to any one of claims 1 to 6.
In the first directional view, the plurality of recesses formed in the interconnector are arranged in a grid pattern arranged in a direction orthogonal to the second direction and in the second direction.
The specific cross section is an electrochemical reaction unit comprising a plurality of cross sections passing through the recesses that are different from each other. In the electrochemical reaction unit according to any one of claims 1 to 7.
The electrochemical reaction single cell is an electrochemical reaction unit, which is a fuel cell single cell. In an electrochemical reaction cell stack having a plurality of electrochemical reaction units arranged side by side in the first direction.
The electrochemical reaction cell stack, wherein at least one of the plurality of electrochemical reaction units is the electrochemical reaction unit according to any one of claims 1 to 8.

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