JP6867974B2 - 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 with the electrolyte layer in between.

In addition, the power generation unit is a plate-shaped interconnector that prevents mixing of the reaction gas while ensuring electrical connection with other adjacent power generation units, and is arranged between the interconnector and the air electrode to electrify both. It is provided with an air electrode side current collecting member to be connected. Conventionally, it is known that a plurality of substantially square columnar conductive members are used as the air electrode side current collecting member, and the interconnector and the air electrode side current collecting member are integrated members (for example, a patent). Reference 1). In this configuration, the flat plate-shaped portion of the integrated member functions as an interconnector, and a plurality of convex portions formed so as to project from the flat plate-shaped portion toward the air electrode are current collecting members on the air electrode side. Functions as.

Japanese Unexamined Patent Publication No. 2018-41570

In the power generation unit, in order to suppress the decrease in gas diffusivity in the air chamber facing the air electrode and the increase in pressure loss, it is preferable to secure the height of the air chamber to some extent or more. In the conventional configuration of the interconnector and the air electrode side current collecting member, if the height of the air electrode side current collecting member is increased to some extent or more in order to secure the height of the air chamber to some extent or more, the air electrode side current collecting member becomes There is a problem that the weight is increased, and as a result, for example, the heat capacity is increased and the startability of the device is lowered. Further, since the integrated member of the conventional interconnector and the air electrode side current collecting member is generally manufactured by press working, the press pressure is required to increase the height of the air electrode side current collecting member to a certain level or more. It is necessary to increase the size and press time, which poses a problem in terms of ease of manufacture.

It should be noted that such a problem is not limited to the air electrode side current collector member arranged between the interconnector and the air electrode, but also to the fuel electrode side current collector member arranged between the interconnector and the fuel electrode. This is a common issue. Further, such a problem is not limited to the fuel cell power generation unit, but 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. This is also a common issue for electrolytic cell units. 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 the solid oxide fuel cell but also to other types of electrochemical reaction units.

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

The techniques disclosed herein 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 with the electrolyte layer interposed therebetween, and the electricity. A plate-shaped interconnector arranged on the specific electrode side of at least one of the air electrode and the fuel electrode of the chemical reaction single cell, and a collection of conductivity arranged between the interconnector and the specific electrode. In the electrochemical reaction unit including the electric member, the current collecting member has a plate-like shape in contact with the surface of the interconnector, and has a base portion having a through hole extending in the first direction and the first one. A plurality of plate-shaped cell contact portions that are arranged so as to overlap the through holes of the base portion and are in contact with the surface of the specific electrode, and the penetrations at the ends of the cell contact portions and the base portion. The electrochemical reaction unit is further composed of an elastic body and is housed in the through hole of the base portion in the first direction, including a connecting portion connecting an end facing the hole. Moreover, a spacer having a shape extending from the surface of the interconnector to the surface of each cell contact portion is provided.

The electrochemical reaction unit includes a plate-shaped interconnector and a conductive current collecting member arranged between the interconnector and the specific electrode. The current collecting member includes a plate-shaped base portion in contact with the surface of the interconnector, a plurality of plate-shaped cell contact portions in contact with the surface of the specific electrode, and a connecting portion connecting each cell contact portion and the base portion. Therefore, according to this electrochemical reaction unit, the increase in the weight of the current collector member is suppressed by adjusting the length and angle of the connecting portion to keep the distance between the base portion and the cell contact portion above a certain level. However, the height of the gas chamber can be easily secured above a certain level. Further, since the current collector member having such a structure can be easily manufactured by, for example, punching or bending a flat plate material, it is also excellent in terms of ease of manufacture.

However, in such a configuration of the current collecting member, the rigidity (difficulty of deformation) at each position of the current collecting member is not uniform. Specifically, the rigidity of the current collecting member at the position of the connecting portion is higher than the rigidity of the current collecting member at the position of the cell contact portion. Therefore, when a load is applied to the electrochemical reaction unit in the first direction, stress is concentrated near the connecting portion of the current collector member, which may cause cracking of the electrochemical reaction single cell. is there.

However, the electrochemical reaction unit includes a spacer made of an elastic body. The spacer is housed in the through hole of the base portion of the current collecting member in the first direction, and has a shape extending from the surface of the interconnector to the surface of each cell contact portion. Therefore, the presence of the spacer supplements the rigidity of the contact portion of each cell of the current collector member, and as a result, it is possible to suppress the concentration of stress near the connecting portion, and the electrochemical reaction single cell cracks. Can be suppressed.

Further, in this electrochemical reaction unit, the spacer has a shape extending from the surface of the interconnector to the surface of each cell contact portion in the first direction, and does not overlap with the base portion (runs on the base portion). Absent). Therefore, as compared with the configuration in which the spacer rides on the base portion, the concentration of stress at each position of the current collecting member can be effectively suppressed, and it is effective that the electrochemical reaction single cell cracks. Can be suppressed.

As described above, according to the present electrochemical reaction unit, it is possible to secure the height of the gas chamber to a certain level or more while suppressing the increase in the weight of the current collector member, and to improve the ease of manufacturing the current collector member. At the same time, it is possible to effectively suppress the occurrence of cracking of the electrochemical reaction single cell.

(2) In the electrochemical reaction unit, the thickness of the base portion in the first direction may be one tenth or more of the thickness of the electrochemical reaction single cell in the first direction. Good. In this electrochemical reaction unit, the thickness of the base portion in the first direction is relatively thick. In a configuration in which the thickness of the base portion is relatively thick, when the spacer rides on the base portion, stress tends to be particularly concentrated near the position where the spacer rides on the base portion. In this electrochemical reaction unit, the spacer is shaped so as to extend from the surface of the interconnector to the surface of each cell contact portion in the first direction, and does not ride on the base portion, so that the thickness of the base portion is increased. Even in a relatively thick structure, the concentration of stress at each position of the current collecting member can be effectively suppressed, and the occurrence of cracking of the electrochemical reaction single cell can be effectively suppressed.

(3) In the electrochemical reaction unit, the boundary between each cell contact portion and each said connecting portion is substantially parallel to the second direction orthogonal to the first direction, and the spacer is the second. The structure may be such that the base portion is in contact with the inner peripheral surface of the through hole so that the movement along the direction of the base portion is restricted. According to the present electrochemical reaction unit, the displacement of the spacer in the second direction can be suppressed. Therefore, according to this electrochemical reaction unit, the spacer is displaced in the second direction and does not come into contact with a part of the cell contact portion, and the stress is concentrated in the vicinity of the connecting portion corresponding to the cell contact portion, and the electrochemical reaction is performed. It is possible to suppress the occurrence of a situation in which the reaction single cell is cracked.

(4) In the electrochemical reaction unit, the boundary between each cell contact portion and each said connecting portion is substantially parallel to the second direction orthogonal to the first direction, and the spacer is the first. The configuration may be such that the base portion is in contact with the inner peripheral surface of the through hole so that the movement along the third direction orthogonal to both the direction of the base portion and the second direction is restricted. According to the present electrochemical reaction unit, the displacement of the spacer in the third direction can be suppressed. If the spacer shifts toward the connecting portion in the third direction, the spacer increases the rigidity at the connecting portion, so that stress is concentrated near the connecting portion and cracking of the electrochemical reaction single cell may occur. There is. On the contrary, when the spacer is displaced to the side away from the connecting portion in the third direction, the effect of reinforcing the rigidity at the position of the cell contact portion by the spacer is reduced, so that the stress is also concentrated near the connecting portion and the electrochemical reaction occurs. There is a risk of single cell cracking. According to the present electrochemical reaction unit, the displacement of the spacer in the third direction can be suppressed, so that the occurrence of cracking of the electrochemical reaction single cell can be effectively suppressed.

(5) In the electrochemical reaction unit, a space in which the spacer does not exist is secured between the interconnector and a part of the cell contact portion on the connecting portion side in the first direction. May be good. According to this electrochemical reaction unit, it is possible to reliably suppress the spacer from interfering with the connecting portion of the current collecting member, and such interference applies a stress other than compression (shear stress, etc.) to the spacer, and the spacer is used. Can be prevented from being damaged.

(6) In the electrochemical reaction unit, the boundary between each cell contact portion and each connection portion is substantially parallel to the second direction orthogonal to the first direction, and the first direction and the connection portion are described. The end of each cell contact portion in the third direction orthogonal to both of the second directions, which is opposite to the boundary with the connecting portion, overlaps the spacer in the first directional view. It may be configured. According to this electrochemical reaction unit, the presence of the spacer can improve the contact property (current collector property) between the cell contact portion of the current collector member and the specific electrode, and the electrical performance of the electrochemical reaction unit can be improved. Can be improved.

(7) In the electrochemical reaction unit, the boundary between each cell contact portion and each connection portion is substantially parallel to the second direction orthogonal to the first direction, and the first direction and the connection portion are described. The end of each cell contact portion in the third direction orthogonal to both of the second directions, which is opposite to the boundary with the connecting portion, does not overlap with the spacer in the first directional view. It may be configured. According to this electrochemical reaction unit, even if the thickness of the spacer varies, it is possible to suppress the concentration of stress near the end on the opposite side of the boundary with the connecting portion at each cell contact portion. , Electrochemical reaction It is possible to suppress the occurrence of cracking of a single cell.

(8) In the electrochemical reaction unit, the boundary between each cell contact portion and each connection portion is substantially parallel to the second direction orthogonal to the first direction, and the base portion has the said. A plurality of the through holes arranged side by side in a third direction orthogonal to both the first direction and the second direction are formed, and the electrochemical reaction unit is formed in the plurality of through holes. A configuration may be configured in which a plurality of the spacers provided so as to be separated from each other are provided. According to this electrochemical reaction unit, the spacer suppresses the obstruction of the gas flow in the gas chamber as compared with the configuration in which a plurality of spacers provided corresponding to the plurality of through holes are connected to each other. It is possible to improve the gas diffusivity and reduce the pressure loss.

(9) In the electrochemical reaction unit, the boundary between each of the cell contact portions and each of the connecting portions is substantially parallel to the second direction orthogonal to the first direction, and the cell contact portion of each of the cell contact portions. The width along the second direction may be smaller than the width along the third direction orthogonal to both the first direction and the second direction. According to this electrochemical reaction unit, the area that becomes the main gas flow path while increasing the total area of the cell contact portion that exerts the current collecting function with respect to the total area of the current collecting member in the first direction view. Can be increased, so that the performance of the electrochemical reaction unit can be further 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 XZ 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 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-sectional structure of two power generation units 102 adjacent to each other at the position of VI-VI of FIG. 7 and 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 FIGS. 4 to 6. It is explanatory drawing which shows the XY cross-sectional structure of the power generation unit 102 at the position of VIII-VIII of FIGS. 4 to 6. It is explanatory drawing which shows schematic structure of the power generation unit 102a in 2nd Embodiment. It is explanatory drawing which shows schematic structure of the air electrode side current collecting member 134 in the 1st modification. It is explanatory drawing which shows schematic structure of the air electrode side current collecting member 134 in the 2nd modification. It is explanatory drawing which shows schematic structure of the air electrode side current collector 134 in the 3rd modification.

A. First Embodiment:
A-1. Device configuration:
(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 a perspective view of the fuel cell stack 100 at the position II-II of FIG. 1 (and FIGS. 7 and 8 described later). It is explanatory drawing which shows the XZ cross-sectional structure, and FIG. 3 is the explanatory view which shows the XZ cross-sectional structure of the fuel cell stack 100 at the position III-III of FIG. 1 (and FIG. 7 and FIG. 8 described later). 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 in a direction different from such an orientation. It may be installed. The same applies to FIGS. 4 and later. Further, in the present specification, the direction orthogonal to the Z-axis direction is referred to as a plane direction.

The fuel cell stack 100 includes a plurality of (seven in this embodiment) fuel cell power generation units (hereinafter, simply referred to as “power generation units”) 102, and a pair of end plates 104 and 106. The seven power generation units 102 are arranged side by side in a predetermined 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.

As shown in FIG. 1, each layer is vertically penetrated around the four corners of the outer periphery of each layer (each power generation unit 102, end plate 104, 106) constituting the fuel cell stack 100 in the Z-axis direction. The holes are formed, and the holes formed in each layer and corresponding to each other communicate with each other in the vertical direction to form a bolt hole 109 extending in the vertical direction from one end plate 104 to the other end plate 106. A bolt 22 is inserted into each bolt hole 109, and the fuel cell stack 100 is fastened by each bolt 22 and a nut (not shown).

Further, as shown in FIGS. 1 to 3, holes are formed in the vicinity of the outer periphery of each power generation unit 102 around the Z-axis direction in the vertical direction, and each power generation unit 102 is formed. The holes corresponding to each other are vertically communicated with each other to form a communication hole 108 extending in the vertical direction over a plurality of power generation units 102. In the following description, the holes formed in each power generation unit 102 to form the communication holes 108 may also be referred to as communication holes 108.

As shown in FIGS. 1 and 2, the fuel cell stack 100 is located near 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. The communication hole 108 is a gas flow path in which the oxidant gas OG is introduced from the outside of the fuel cell stack 100 and the oxidant gas OG is supplied to the air chamber 166 described later in each power generation unit 102. The communication hole 108 located near 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) is from the air chamber 166 of each power generation unit 102. It functions as an oxidant gas discharge manifold 162, which is a gas flow path for discharging the oxidant off gas OOG, which is the discharged gas, to the outside of the fuel cell stack 100. As the oxidant gas OG, for example, air is used.

Further, as shown in FIGS. 1 and 3, among the sides constituting the outer periphery of the fuel cell stack 100 in the Z-axis direction, the vicinity of the side closest to the communication hole 108 functioning as the above-mentioned oxidant gas discharge manifold 162. In the other communication hole 108 located in, the fuel gas FG is introduced from the outside of the fuel cell stack 100, and the fuel gas FG is introduced into the fuel gas flow path which is a gas flow path for supplying the fuel gas FG to the fuel chamber 176 described later in each power generation unit 102. The other communication holes 108 located near the side closest to the communication holes 108 that function as the manifold 171 and function as the oxidant gas introduction manifold 161 described above are the gases discharged from the fuel cell 176 of each power generation unit 102. It functions as a fuel gas discharge manifold 172, which is a gas flow path for discharging a certain fuel off-gas FOG to the outside of the fuel cell stack 100. As the fuel gas FG, for example, a hydrogen-rich gas obtained by reforming city gas is used.

(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. As shown in FIGS. 2 and 3, four flow path through holes 107 are formed in the lower end plate 106. The four flow path through holes 107 communicate with the oxidant gas introduction manifold 161, the oxidant gas discharge manifold 162, the fuel gas introduction manifold 171 and the fuel gas discharge manifold 172, respectively.

(Structure of gas passage member 27, etc.)
As shown in FIGS. 2 and 3, the fuel cell stack 100 further has four gas passages arranged on the opposite side (that is, the lower side) of the plurality of power generation units 102 with respect to the lower end plate 106. A member 27 is provided. The four gas passage members 27 are arranged at positions overlapping with the oxidant gas introduction manifold 161, the oxidant gas discharge manifold 162, the fuel gas introduction manifold 171 and the fuel gas discharge manifold 172, respectively. Each gas passage member 27 has a main body portion 28 in which a hole communicating with the flow path through hole 107 of the lower end plate 106 is formed, and a tubular branch portion 29 branched from the side surface of the main body portion 28. doing. 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. An insulating sheet 26 is arranged between the main body 28 of each gas passage member 27 and the end plate 106. 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.

(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 the XZ cross-sectional configuration of the 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 XZ cross-sectional structure of two power generation units 102, and FIG. 6 is the explanatory view which shows the YZ cross-sectional structure of two power generation units 102 which are adjacent to each other at the position of VI-VI of FIG. 7 and FIG. Is. Further, FIG. 7 is an explanatory view showing an XY cross-sectional configuration of the power generation unit 102 at the position of VII-VII of FIGS. 4 to 6, and FIG. 8 is a power generation unit at the position of VIII-VIII of FIGS. 4 to 6. It is explanatory drawing which shows the XY cross-sectional structure of 102.

As shown in FIGS. 4 to 6, the power generation unit 102 includes a single cell 110, a separator 120, an air pole side frame 130, an air pole side current collector 134, a fuel pole side frame 140, and a fuel pole side. It includes a current collector member 144 and a pair of interconnectors 150 that form the uppermost layer and the lowermost layer of the power generation unit 102. Holes forming communication holes 108 that function as the above-mentioned manifolds 161, 162, 171 and 172 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. Or, holes forming each bolt hole 109 are formed.

The interconnector 150 is a substantially rectangular flat plate-shaped conductive member, and is made of, for example, ferritic stainless steel. The interconnector 150 is a member for ensuring an electrical connection between the power generation units 102 and preventing mixing of the reaction gas between the power generation units 102. In the present embodiment, the surface of the interconnector 150 on the side facing the air electrode 114, which will be described later, is covered with the conductive coat 151. Coating 151, for _example, it is formed by Mn 2 CoO ₄ and _{MnCo 2 O 4, ZnCo 2 O} 4, ZnMnCoO 4, spinel oxides such CuMn ₂ O _4. The formation of the coat 151 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 151 suppresses the release and diffusion of Cr (chromium) from the interconnector 150 to the air electrode 114 side, Cr adheres to the surface of the air electrode 114, and the electrode reaction rate at the air electrode 114 decreases. The occurrence of a phenomenon called "Cr poisoning of the air electrode 114" is suppressed. In the following description, unless otherwise specified, "interconnector 150" means "interconnector 150 covered with coat 151". Further, 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 (see FIGS. 2 and 3).

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 flat plate-shaped member that is substantially rectangular in the Z-axis direction, and is a dense layer. The electrolyte layer 112 is formed of, for example, a solid oxide such as YSZ (yttria-stabilized zirconia), ScSZ (scandia-stabilized zirconia), SDC (samarium-doped ceria), GDC (gadolinium-doped ceria), and perovskite-type oxide. There is. The air electrode 114 is a substantially rectangular flat plate-shaped member smaller than the electrolyte layer 112 in the Z-axis direction, and is a porous layer. The air electrode 114 is formed of, for example, a perovskite type oxide (for example, LSCF (lanternstrontium cobalt iron oxide), LSM (lanternstrontium manganese oxide), LNF (lantern nickel iron)). The air electrode 114 in this embodiment corresponds to a specific electrode in the claims. The fuel electrode 116 is a substantially rectangular flat plate-shaped member having substantially the same size as the electrolyte layer 112 in the Z-axis direction, and is a porous layer. The fuel electrode 116 is formed of, for example, a cermet composed of Ni and oxide ion conductive ceramic particles (for example, YSZ). 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 made of, for example, a metal such as stainless steel. 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. A seal member (for example, a glass seal member) that seals between the air chamber 166 and the fuel chamber 176 may be further provided near the joint between the single cell 110 and the separator 120.

As shown in FIGS. 4 to 7, 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 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 holes 131 formed in the air electrode side frame 130 form an air chamber 166 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 flow path 132 that communicates the oxidant gas introduction manifold 161 and the air chamber 166, and the oxidant that communicates the air chamber 166 and the oxidant gas discharge manifold 162. A gas discharge communication flow path 133 is formed.

As shown in FIGS. 4 to 6 and 8, the fuel electrode side frame 140 is a frame-shaped member in which a substantially rectangular hole 141 penetrating in the vertical direction is formed near the center, and is, for example, a metal such as stainless steel. Is formed by. 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. A hole 141 formed in the fuel electrode side frame 140 constitutes a fuel chamber 176 facing the fuel electrode 116. Further, in the fuel electrode side frame 140, a fuel gas supply communication flow path 142 that communicates the fuel gas introduction manifold 171 and the fuel chamber 176, and a fuel gas discharge communication flow that communicates the fuel chamber 176 and the fuel gas discharge manifold 172. A road 143 is formed.

As shown in FIGS. 4 to 7, the air electrode side current collecting member 134 is a conductive member arranged between the interconnector 150 and the air electrode 114 of the single cell 110, and is formed of, for example, ferritic stainless steel. Has been done. The air pole side current collecting member 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 collecting member 134 in the power generation unit 102 is the upper end plate. It is in contact with 104. Since the air electrode side current collecting member 134 has such a configuration, the air electrode 114 and the interconnector 150 (or the end plate 104) are electrically connected. The configuration of the air electrode side current collecting member 134 will be described in more detail later.

In the present embodiment, the air electrode side current collecting member 134 is covered with a conductive coat 38 similar to the coat 151 covering the above-mentioned interconnector 150. As a result, the release / diffusion of Cr from the current collecting member 134 on the air electrode side is suppressed, and the generation of Cr poisoning of the air electrode 114 is suppressed. In the following description, unless otherwise specified, the "air pole side current collecting member 134" means the "air pole side current collecting member 134 covered with the coat 38". Further, in the present embodiment, the air electrode side current collecting member 134 and the air electrode 114 are bonded by a conductive bonding layer 138. The bonding layer 138 is formed of, for example, spinel-type oxides such as _{Mn 2} CoO ₄ , Mn Co ₂ O ₄ , ZnCo ₂ O ₄ , ZnMn CoO ₄ , and CuMn ₂ O _4. The bonding layer 138 is formed, for example, by printing the bonding layer paste on the current collecting member 134 on the air electrode side and firing the bonding layer paste under predetermined conditions while pressing the bonding layer paste against the surface of the air electrode 114. can do. In the present specification, when the air electrode side current collecting member 134 is in contact with the surface of the air electrode 114, the two are in contact with each other via a bonding layer 138 that joins the air electrode side current collecting member 134 and the air electrode 114. including.

As shown in FIGS. 4 to 6 and 8, the fuel electrode side current collecting member 144 is a conductive member arranged between the interconnector 150 and the fuel electrode 116 of the single cell 110, and is, for example, nickel or It is formed of nickel alloy foil or mesh. The fuel pole side current collecting member 144 is in contact with the surface of the fuel pole 116 on the side opposite to the side facing the electrolyte layer 112 and the surface of the interconnector 150 on the side facing the fuel pole 116. 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 fuel electrode side current collecting member 144 in the power generation unit 102 is on the lower side. It is in contact with the end plate 106. Since the fuel pole side current collecting member 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 configuration of the fuel electrode side current collector 144 will be described in more detail later.

The fuel electrode side current collector 144 and the fuel electrode 116 may be joined by a conductive bonding layer. In that case, when the fuel electrode side current collector 144 comes into contact with the surface of the fuel electrode 116. Includes a state in which the fuel electrode side current collector 144 and the fuel electrode 116 are in contact with each other via a bonding layer.

A-2. Operation of fuel cell stack 100:
As shown in FIGS. 2, 4 and 7, the oxidant gas is passed through a gas pipe (not shown) connected to the branch portion 29 of the gas passage member 27 provided at the position of the oxidant gas introduction manifold 161. When the OG is supplied, the oxidant gas OG is delivered to the oxidant gas introduction manifold 161 via the branch portion 29 of the gas passage member 27, the main body portion 28, and the through hole 107 for the flow path of the lower end plate 106. Is supplied to the air chamber 166 from the oxidant gas introduction manifold 161 via the oxidant gas supply communication flow path 132 of each power generation unit 102. Further, as shown in FIGS. 3, 5 and 8, the fuel gas is passed through a gas pipe (not shown) connected to the branch portion 29 of the gas passage member 27 provided at the position of the fuel gas introduction manifold 171. When the FG is supplied, the fuel gas FG is supplied to the fuel gas introduction manifold 171 via the branch portion 29 of the gas passage member 27, the main body portion 28, and the through hole 107 for the flow path of the lower end plate 106. Then, it is supplied from the fuel gas introduction manifold 171 to the fuel chamber 176 via the fuel gas supply communication flow path 142 of each power generation unit 102.

When the oxidant gas OG is supplied to the air chamber 166 of each power generation unit 102 and the fuel gas FG is supplied to the fuel chamber 176, oxygen contained in the oxidant gas OG and hydrogen contained in the fuel gas FG in the single cell 110 are supplied. Power is generated by the electrochemical reaction with. 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 of the interconnectors 150 via the air pole side current collector 134, and the fuel pole 116 is via the fuel pole side current collector 144. It is electrically connected to the other interconnector 150. Further, the plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. Therefore, the electric energy generated in each power generation unit 102 is taken out from the end plates 104 and 106 that function as the output terminals of the fuel cell stack 100. Since the SOFC generates electricity at a relatively high temperature (for example, 700 ° C. to 1000 ° C.), the fuel cell stack 100 is a heater (for example, after the start-up, until the high temperature can be maintained by the heat generated by the power generation. It may be heated by (not shown).

The oxidant off-gas OOG discharged from the air chamber 166 of each power generation unit 102 is discharged to the oxidant gas discharge manifold 162 via the oxidant gas discharge communication flow path 133 as shown in FIGS. 2, 4 and 7. Then, it is connected to the branch portion 29 via the main body portion 28 and the branch portion 29 of the gas passage member 27 provided at the position of the through hole 107 for the flow path of the lower end plate 106 and the oxidant gas discharge manifold 162. It is discharged to the outside of the fuel cell stack 100 via the gas pipe (not shown). Further, the fuel off-gas FOG discharged from the fuel chamber 176 of each power generation unit 102 is discharged to the fuel gas discharge manifold 172 via the fuel gas discharge communication flow path 143 as shown in FIGS. 3, 5, and 8. Further, it was connected to the branch portion 29 via the through hole 107 for the flow path of the lower end plate 106, the main body portion 28 and the branch portion 29 of the gas passage member 27 provided at the position of the fuel gas discharge manifold 172. It is discharged to the outside of the fuel cell stack 100 via a gas pipe (not shown).

In each power generation unit 102 constituting the fuel cell stack 100 of the present embodiment, the main flow direction of the oxidizing agent gas OG in the air chamber 166 (as shown in FIG. 7, from the X-axis positive direction side to the X-axis negative direction side). (Direction toward) and the main flow direction of the fuel gas FG in the fuel chamber 176 (direction from the negative X-axis side to the positive X-axis side as shown in FIG. 8) are substantially opposite directions (directions facing each other). ). That is, the power generation unit 102 (fuel cell stack 100) of the present embodiment is a counterflow type SOFC.

A-3. Detailed configuration of the fuel electrode side current collector 144:
Next, the detailed configuration of the fuel electrode side current collector 144 will be described. As shown in FIGS. 4 to 6 and 8, the fuel electrode side current collecting member 144 has a base portion 146, a plurality of cell contact portions 145, and a plurality of connecting portions 147.

The base portion 146 of the fuel pole side current collector 144 is in contact with the surface of the interconnector 150 (or the end plate 106, the same applies hereinafter) on the side facing the fuel pole 116, and is electrically connected to the interconnector 150. It is a plate-shaped part. The base portion 146 is joined to the interconnector 150 by, for example, laser welding or resistance welding. The base portion 146 is formed with a plurality of through holes 40 that penetrate the base portion 146 in the thickness direction (that is, extend in the Z-axis direction).

Each cell contact portion 145 of the fuel pole side current collector 144 is a plate-shaped portion of the fuel pole 116 that is in contact with the surface of the fuel pole 116 opposite to the side facing the electrolyte layer 112 and is electrically connected to the fuel pole 116. Is. The shape of each cell contact portion 145 in the Z-axis direction is substantially rectangular. Further, the plurality of cell contact portions 145 are arranged in a grid pattern along the X direction and the Y direction in the Z-axis direction. Each cell contact portion 145 is arranged so as to overlap the base portion 146 in the Z-axis direction.

Each connecting portion 147 of the fuel electrode side current collecting member 144 is a plate-shaped portion connecting the end portion of each cell contact portion 145 and the end portion of the base portion 146 facing the through hole 40.

As described above, the fuel electrode side current collecting member 144 includes a base portion 146 electrically connected to the interconnector 150, a plurality of cell contact portions 145 electrically connected to the fuel electrode 116, and each cell contact portion. Since it has a connecting portion 147 connecting the 145 and the base portion 146, the fuel electrode 116 and the interconnector 150 are electrically connected as described above.

The fuel electrode side current collector 144 having such a configuration is completed, for example, by punching a flat plate material for manufacturing the fuel electrode side current collector 144, as shown in the partially enlarged view in FIG. In the state, cuts are made in each of the three sides of the rectangular region that becomes each cell contact portion 145 and each connecting portion 147, and then the flat plate material after the punching process is bent to form each cell contact portion 145 and each connecting portion 147. It can be manufactured by forming each connecting portion 147. In the partially enlarged view of FIG. 8, in order to show the method of manufacturing the fuel electrode side current collector 144, a part of the state before the bending process is shown.

A fuel pole side spacer 149 formed of an elastic material (elastic body) such as mica is arranged between each cell contact portion 145 and the base portion 146 of the fuel pole side current collector member 144. Due to the presence of the fuel pole side spacer 149, 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 via the fuel pole side current collector 144. Good electrical connection with 150 (or end plate 106) is maintained.

A-4. Detailed configuration of the air electrode side current collector 134:
Next, the detailed configuration of the air electrode side current collecting member 134 will be described. As shown in FIGS. 4 to 7, the air electrode side current collecting member 134 has a base portion 136, a plurality of cell contact portions 135, and a plurality of connecting portions 137.

The base portion 136 of the air electrode side current collecting member 134 is in contact with the surface of the interconnector 150 (or the end plate 104, the same applies hereinafter) on the side facing the air electrode 114, and is electrically connected to the interconnector 150. It is a plate-shaped part. In the present embodiment, the thickness of the base portion 136 (the size in the Z-axis direction) is one tenth or more of the thickness of the single cell 110. The thickness of the base portion 136 is preferably less than half the height of the air chamber 166 (distance from the surface of the air electrode 114 to the surface of the interconnector 150). The thickness of the base portion 136 is, for example, 0.1 mm to 0.5 mm. The base portion 136 is joined to the interconnector 150 by, for example, laser welding or resistance welding. The base portion 136 is formed with a plurality of through holes 30 that penetrate the base portion 136 in the thickness direction (that is, extend in the Z-axis direction). As shown in FIG. 7, in the present embodiment, each through hole 30 formed in the base portion 136 is a hole having a long shape in the X-axis direction. Further, in the base portion 136, the plurality of through holes 30 are arranged so as to be arranged in the Y-axis direction.

Each cell contact portion 135 of the air pole side current collecting member 134 is a plate-shaped portion of the air pole 114 that is in contact with the surface of the air pole 114 on the side opposite to the side facing the electrolyte layer 112 and is electrically connected to the air pole 114. Is. The shape of each cell contact portion 135 in the Z-axis direction is substantially rectangular. Further, the plurality of cell contact portions 135 are arranged in a grid pattern along the X direction and the Y direction in the Z-axis direction. Each cell contact portion 135 is arranged so as to overlap the through hole 30 formed in the base portion 136 in the Z-axis direction. In the present embodiment, the width W1 of each cell contact portion 135 along the X-axis direction is smaller than the width W2 along the Y-axis direction. Further, the end 33 on the Y-axis positive direction side of each cell contact portion 135 is a free end that is not fixed or connected to anything. The X-axis direction corresponds to the second direction in the claims, and the Y-axis direction corresponds to the third direction in the claims.

Each connecting portion 137 of the air electrode side current collecting member 134 has a plate shape connecting the end portion 32 on the negative direction side of the Y axis in each cell contact portion 135 and the end portion 31 facing the through hole 30 in the base portion 136. It is a part. Each connecting portion 137 is not parallel to the cell contact portion 135 or the base portion 136. That is, each connecting portion 137 has a plate shape that intersects a virtual plane (XY plane) orthogonal to the Z-axis direction. Further, the boundary between each connecting portion 137 and each cell contact portion 135 is substantially parallel in the X-axis direction.

As described above, the air electrode side current collecting member 134 includes a base portion 136 electrically connected to the interconnector 150, a plurality of cell contact portions 135 electrically connected to the air electrode 114, and each cell contact portion. Since it has a connecting portion 137 connecting the 135 and the base portion 136, the air electrode 114 and the interconnector 150 are electrically connected as described above.

The air electrode side current collecting member 134 having such a configuration is formed by punching, for example, a flat plate member for manufacturing the air electrode side current collecting member 134, so that each cell contact portion 135 and each connecting portion are in a completed state. A hole corresponding to the outer shape of each through hole 30 is formed while leaving a portion to be 137, and then the flat plate member after the hole is bent to form each cell contact portion 135 and each connecting portion 137. By doing so, it can be produced.

An air electrode side spacer 139 is arranged between each cell contact portion 135 of the air electrode side current collecting member 134 and the interconnector 150. The air electrode side spacer 139 is a member having a substantially rectangular parallelepiped shape, and is formed of an elastic material (elastic body) such as mica. In the present specification, the elastic material (elastic body) means a material having a Young's modulus of 100 GPa or less. In the present embodiment, one air pole side spacer 139 is provided for each of the groups composed of the plurality of cell contact portions 135 arranged in the X-axis direction. The air electrode side spacers 139 corresponding to each group of the cell contact portions 135 are separated from each other.

As shown in FIGS. 6 and 7, each air electrode side spacer 139 has a shape extending from the surface of the interconnector 150 to the surface of each cell contact portion 135 in the Z-axis direction. Each air pole side spacer 139 (more specifically, a part of the air pole side spacer 139 on the interconnector 150 side) is a through hole 30 formed in the base portion 136 of the air pole side current collector member 134 in the Z-axis direction. It is housed inside. That is, each air pole side spacer 139 does not overlap with the base portion 136 of the air pole side current collecting member 134 in the Z-axis direction (does not ride on the base portion 136).

Further, as shown in FIG. 7, each air pole side spacer 139 is formed from one end to the other end of the through hole 30 formed in the base portion 136 of the air pole side current collecting member 134 in the X-axis direction. It has a shape that extends to. Therefore, each air electrode side spacer 139 is in contact with the inner peripheral surface of the through hole 30 in the positive direction of the X-axis and the negative direction of the X-axis. That is, each air electrode side spacer 139 is in contact with the inner peripheral surface of the through hole 30 so that the movement along the X-axis direction is restricted. In addition, in this specification, the fact that two members are in contact with each other is not limited to the mode in which the two members are in contact with each other, and the minimum value of the distance between the two members is 1 mm or less. means. If the minimum value of the distance between each air pole side spacer 139 and the inner peripheral surface of the through hole 30 is 1 mm or less, it can be said that the movement of each air pole side spacer 139 along the X-axis direction is restricted.

Further, as shown in FIG. 7, the portion of each through hole 30 formed in the base portion 136 on the positive direction side of the Y-axis constitutes a wide portion 34 having a width in the X-axis direction wider than the other portions. Each air electrode side spacer 139 has a shape extending from one end to the other end of the wide portion 34 of the through hole 30 in the Y-axis direction. Therefore, each air electrode side spacer 139 abuts on the inner peripheral surface of the wide portion 34 of the through hole 30 in the positive direction of the Y axis, and the inner peripheral surface (wide) of the wide portion 34 of the through hole 30 in the negative direction of the Y axis. It is in contact with the interface) between the portion 34 and the other portion. That is, each air electrode side spacer 139 is in contact with the inner peripheral surface of the through hole 30 (the wide portion 34) so that the movement along the Y-axis direction is restricted. As described above, in the present specification, the fact that two members are in contact with each other is not limited to the mode in which the two members are in contact with each other, and the minimum value of the distance between the two members is 1 mm or less. It means that there is. If the minimum value of the distance between each air pole side spacer 139 and the inner peripheral surface of the through hole 30 (wide portion 34) is 1 mm or less, the movement of each air pole side spacer 139 along the Y-axis direction is performed. It can be said that it is regulated.

Further, since each air electrode side spacer 139 has the above-described configuration, the end portion (free end) 33 on the side opposite to the boundary with the connecting portion 137 in each cell contact portion 135 of the air electrode side current collecting member 134. Overlaps the air electrode side spacer 139 in the Z-axis direction (see FIGS. 6 and 7). Further, in the Z-axis direction, a space 39 in which the air electrode side spacer 139 does not exist is secured between the interconnector 150 and a part of the air electrode side current collecting member 134 on the connecting portion 137 side of each cell contact portion 135. (See Fig. 6). In other words, in the Z-axis direction, there is a space 39 between the interconnector 150 and a part of the air electrode side current collecting member 134 on the connecting portion 137 side of each cell contact portion 135, and the space 39 has a space 39. There is no member including the air electrode side spacer 139. That is, a part of the air electrode side current collecting member 134 on the connecting portion 137 side of each cell contact portion 135 faces (faces) the interconnector 150 in the Z-axis direction without interposing another member. ..

A-5. 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, an interconnector 150, and an air electrode side current collecting member 134. 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 with the electrolyte layer 112 interposed therebetween. The interconnector 150 is a plate-shaped member arranged on the air electrode 114 side of the single cell 110. The air electrode side current collecting member 134 is a conductive member arranged between the interconnector 150 and the air electrode 114. The air electrode side current collecting member 134 includes a base portion 136, a plurality of cell contact portions 135, and a connecting portion 137. The base portion 136 is a plate-shaped member in contact with the surface of the interconnector 150, and a through hole 30 extending in the Z-axis direction is formed. Each cell contact portion 135 is a plate-shaped member that is arranged so as to overlap the through hole 30 of the base portion 136 in the Z-axis direction and is in contact with the surface of the air electrode 114. The connecting portion 137 is a member that connects the end portion 32 of each cell contact portion 135 and the end portion 31 facing the through hole 30 in the base portion 136. Further, the power generation unit 102 further includes an air electrode side spacer 139 made of an elastic body. The air electrode side spacer 139 is housed in the through hole 30 of the base portion 136 in the Z-axis direction, and has a shape extending from the surface of the interconnector 150 to the surface of each cell contact portion 135. Since each power generation unit 102 constituting the fuel cell stack 100 of the present embodiment has the above-described configuration, as described below, the air chamber 166 while suppressing an increase in the weight of the air electrode side current collector member 134. It is possible to secure a certain height or more, improve the ease of manufacturing the air electrode side current collecting member 134, and effectively suppress the occurrence of cracking of the single cell 110. ..

In the power generation unit 102, in order to suppress a decrease in gas diffusivity in the air chamber 166 facing the air electrode 114 and suppress an increase in pressure loss, it is necessary to secure a certain height or more of the air chamber 166. preferable. In the conventional configuration in which a plurality of substantially square columnar conductive members are used as the air electrode side current collecting member, the height of the air electrode side current collecting member is increased to some extent or more in order to secure the height of the air chamber 166 to some extent or more. There is a problem that the weight of the current collector on the air electrode side increases, and as a result, for example, the heat capacity increases and the startability of the device decreases. Further, in the conventional configuration in which the interconnector and the air electrode side current collecting member are integrated members, the height of the air electrode side current collecting member is set to a certain level or more when the integrated member is manufactured by press working. It is necessary to increase the press pressure and lengthen the press time, which poses a problem in terms of ease of manufacture.

On the other hand, the power generation unit 102 of the present embodiment includes a plate-shaped interconnector 150 and a conductive air electrode side current collecting member 134 arranged between the interconnector 150 and the air electrode 114. The air electrode side current collecting member 134 includes a plate-shaped base portion 136 in contact with the surface of the interconnector 150, a plurality of plate-shaped cell contact portions 135 in contact with the surface of the air electrode 114, and each cell contact portion 135 and the base portion. Includes a connecting portion 137 connecting with 136. Therefore, according to the power generation unit 102 of the present embodiment, the distance between the base portion 136 and the cell contact portion 135 is set to a certain value or more by adjusting the length and angle of the connecting portion 137, thereby collecting the air pole side. It is possible to easily secure the height of the air chamber 166 or more while suppressing an increase in the weight of the electric member 134. Further, the air electrode side current collector 134 having such a configuration can be easily manufactured by, for example, punching or bending a flat plate material, and is therefore excellent in terms of ease of manufacture.

However, in the configuration of the air electrode side current collecting member 134 in the present embodiment, the rigidity (difficulty of deformation) at each position of the air electrode side current collecting member 134 is not uniform. Specifically, the rigidity of the air electrode side current collecting member 134 at the position of the connecting portion 137 is compared with the rigidity of the air electrode side current collecting member 134 at the position of the cell contact portion 135 (particularly near the free end 33). It gets higher. Therefore, when a load in the Z-axis direction is applied to the power generation unit 102 (fuel cell stack 100), stress is concentrated in the vicinity of the connecting portion 137 of the air electrode side current collecting member 134, and as a result, the single cell 110 There is a risk of cracking.

However, the power generation unit 102 of the present embodiment includes an air electrode side spacer 139 made of an elastic body. The air pole side spacer 139 is housed in the through hole 30 of the base portion 136 of the air pole side current collecting member 134 in the Z-axis direction, and from the surface of the interconnector 150 to the surface of each cell contact portion 135. It has an elongated shape. Therefore, the presence of the air electrode side spacer 139 supplements the rigidity of each cell contact portion 135 of the air electrode side current collector member 134, and as a result, it is possible to suppress the concentration of stress in the vicinity of the connecting portion 137. It is possible to suppress the occurrence of cracking of the single cell 110.

Further, in the power generation unit 102 of the present embodiment, the air electrode side spacer 139 has a shape extending from the surface of the interconnector 150 to the surface of each cell contact portion 135 in the Z-axis direction, and overlaps with the base portion 136. Not (not on the base 136). Therefore, as compared with the configuration in which the air electrode side spacer 139 rides on the base portion 136, stress concentration at each position of the air electrode side current collecting member 134 can be effectively suppressed, and the single cell 110 is cracked. Can be effectively suppressed from occurring.

As described above, according to the power generation unit 102 of the present embodiment, it is possible to secure the height of the air chamber 166 or more while suppressing the increase in the weight of the air electrode side current collecting member 134, and the air electrode side. The ease of manufacturing the current collecting member 134 can be improved, and the occurrence of cracks in the single cell 110 can be effectively suppressed.

In particular, in the power generation unit 102 of the present embodiment, the thickness of the base portion 136 of the air electrode side current collecting member 134 in the Z-axis direction is relatively thick, which is one tenth or more of the thickness of the single cell 110. In a configuration in which the thickness of the base portion 136 is relatively thick, when the air electrode side spacer 139 rides on the base portion 136, stress tends to be particularly concentrated near the position where the air electrode side spacer 139 rides on the base portion 136. As described above, in the power generation unit 102 of the present embodiment, the air electrode side spacer 139 has a shape extending from the surface of the interconnector 150 to the surface of each cell contact portion 135 in the Z-axis direction, and is a base portion. Since it does not ride on 136, even in a configuration in which the base portion 136 is relatively thick, stress concentration at each position of the air electrode side current collecting member 134 can be effectively suppressed, and the single cell 110 can be used. It is possible to effectively suppress the occurrence of cracks.

Further, in the power generation unit 102 of the present embodiment, the air electrode side spacer 139 is arranged in the X-axis direction (in the direction orthogonal to the Z-axis direction, the extending direction of the boundary between each cell contact portion 135 and each connecting portion 137). It is in contact with the inner peripheral surface of the through hole 30 of the base portion 136 so that the movement along the line is restricted. Therefore, according to the fuel cell power generation unit 102 of the present embodiment, the misalignment of the air electrode side spacer 139 in the X-axis direction can be suppressed. Therefore, according to the fuel cell power generation unit 102 of the present embodiment, the air electrode side spacer 139 is displaced in the X-axis direction and does not come into contact with a part of the cell contact portions 135, and the connecting portion corresponding to the cell contact portion 135. It is possible to suppress the occurrence of a situation in which stress is concentrated in the vicinity of 137 and the single cell 110 is cracked.

Further, in the power generation unit 102 of the present embodiment, the air electrode side spacer 139 is the extending direction of the boundary between each cell contact portion 135 and each connecting portion 137 in the direction orthogonal to the Z axis direction. It is in contact with the inner peripheral surface of the through hole 30 of the base portion 136 so that the movement along the direction perpendicular to the X-axis direction is restricted. Therefore, according to the fuel cell power generation unit 102 of the present embodiment, the misalignment of the air electrode side spacer 139 in the Y-axis direction can be suppressed. When the air electrode side spacer 139 shifts to the side closer to the connecting portion 137 in the Y-axis direction (Y-axis negative direction side), the air electrode side spacer 139 increases the rigidity at the position of the connecting portion 137, so that the vicinity of the connecting portion 137 Stress is concentrated on the cell 110, which may cause cracking of the single cell 110. On the contrary, when the air electrode side spacer 139 shifts to the side away from the connecting portion 137 in the Y-axis direction (Y-axis positive direction side), the effect of reinforcing the rigidity at the position of the cell contact portion 135 by the air electrode side spacer 139 decreases. Therefore, the stress may be concentrated in the vicinity of the connecting portion 137 and the single cell 110 may be cracked. According to the fuel cell power generation unit 102 of the present embodiment, the misalignment of the air electrode side spacer 139 in the Y-axis direction can be suppressed, so that the occurrence of cracking of the single cell 110 can be effectively suppressed. it can.

Further, in the power generation unit 102 of the present embodiment, in the Z-axis direction, the air electrode side spacer 139 is located between the interconnector 150 and a part of the air electrode side current collecting member 134 on the connecting portion 137 side of each cell contact portion 135. Space 39 is secured where there is no such thing. Therefore, according to the power generation unit 102 of the present embodiment, it is possible to surely suppress the air electrode side spacer 139 from interfering with the connecting portion 137 of the air electrode side current collecting member 134, and the air electrode due to such interference. It is possible to prevent the air electrode side spacer 139 from being damaged by applying a stress other than compression (shear stress or the like) to the side spacer 139.

Further, in the power generation unit 102 of the present embodiment, the direction orthogonal to the X-axis direction, which is the extending direction of the boundary between each cell contact portion 135 and each connecting portion 137, among the directions orthogonal to the Z-axis direction. ), The end (free end) 33 on the side opposite to the boundary of each cell contact portion 135 with the connecting portion 137 overlaps with the air electrode side spacer 139 in the Z-axis direction. Therefore, according to the power generation unit 102 of the present embodiment, the presence of the air electrode side spacer 139 provides a contact property (current collector property) between the cell contact portion 135 of the air electrode side current collector member 134 and the air electrode 114. It can be improved, and the electrical performance of the power generation unit 102 can be improved.

Further, in the power generation unit 102 of the present embodiment, each cell contact portion 135 and each connecting portion 137 are connected to the base portion 136 of the air electrode side current collecting member 134 in the Y-axis direction (in the direction orthogonal to the Z-axis direction). A plurality of through holes 30 arranged side by side in a direction orthogonal to the X-axis direction, which is the extending direction of the boundary, are formed, and the power generation unit 102 is provided corresponding to the plurality of through holes 30 and is provided with each other. A plurality of separated air electrode side spacers 139 are provided. Therefore, according to the power generation unit 102 of the present embodiment, the air electrode side spacer 139 is used as compared with the configuration in which the plurality of air electrode side spacers 139 provided corresponding to the plurality of through holes 30 are connected to each other. It is possible to suppress the obstruction of the gas flow in the air chamber 166, improve the gas diffusivity, and reduce the pressure loss.

Further, in the power generation unit 102 of the present embodiment, each cell contact portion 135 and each connecting portion 137 in the X-axis direction (in the direction orthogonal to the Z-axis direction) of each cell contact portion 135 of the air electrode side current collecting member 134. The width W1 along the extending direction of the boundary) is smaller than the width W2 along the Y-axis direction (the direction orthogonal to the Z-axis direction and the direction orthogonal to the X-axis direction). Therefore, according to the power generation unit 102 of the present embodiment, the total area of the cell contact portion 135 that exerts the current collecting function is increased with respect to the total area of the air electrode side current collecting member 134 in the Z-axis direction. Since the area of the main gas flow path (the space extending in the X-axis direction located between the groups composed of the plurality of cell contact portions 135 arranged in the X-axis direction) can be increased, the performance of the power generation unit 102 can be improved. It can be further improved.

B. Second embodiment:
FIG. 9 is an explanatory diagram schematically showing the configuration of the power generation unit 102a in the second embodiment. FIG. 9 shows a configuration of a part of the air pole side current collecting member 134 and the air pole side spacer 139 in the power generation unit 102a of the second embodiment. In the following, among the configurations of the power generation unit 102a of the second embodiment, the same configurations as the configurations of the power generation unit 102 of the first embodiment described above will be appropriately described by adding the same reference numerals.

As shown in FIG. 9, in the power generation unit 102a of the second embodiment, mainly the configuration of the base portion 136 of the air electrode side current collecting member 134 and the configuration of the air electrode side spacer 139 are the power generation of the first embodiment. It is different from the unit 102. Specifically, in the power generation unit 102a of the second embodiment, the edge on the Y-axis positive direction side of the wide portion 34 of each through hole 30 formed in the base portion 136 is each cell of the air electrode side current collecting member 134. The contact portion 135 is located on the Y-axis negative direction side from the end portion (free end) 33 on the side opposite to the boundary with the connecting portion 137. Similar to the power generation unit 102 of the first embodiment, the air electrode side spacer 139 has a shape extending from one end of the wide portion 34 of the through hole 30 to the other end in the Y-axis direction. ing. Therefore, in the power generation unit 102a of the second embodiment, the end (free end) 33 of each cell contact portion 135 of the air pole side current collecting member 134 does not overlap with the air pole side spacer 139 in the Z-axis direction.

Since the power generation unit 102a of the second embodiment has the above configuration, stress is concentrated near the end (free end) 33 of each cell contact portion 135 even if the thickness of the air electrode side spacer 139 varies. It is possible to suppress the occurrence of cracking of the single cell 110.

C. 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.

FIG. 10 is an explanatory diagram schematically showing the configuration of the air electrode side current collecting member 134 in the first modification. As shown in FIG. 10, each cell contact portion 135 of the air electrode side current collecting member 134 intersects the Y axis, not the Y axis direction, from the connection position with the connecting portion 137 (in the Y axis and the X axis). It may be extended in the direction of intersection or in the direction parallel to the X-axis).

FIG. 11 is an explanatory diagram schematically showing the configuration of the air electrode side current collecting member 134 in the second modification. As shown in FIG. 11, the directions in which the connecting portions 137 and the cell contact portions 135 extend from the base portion 136 of the air electrode side current collecting member 134 do not necessarily have to be the same, but are different from each other (for example, the Z axis). In the directional view, some connecting portions 137 and the like extend from the base portion 136 to the negative direction side of the Y axis, and some other connecting portions 137 and the like extend from the base portion 136 to the positive direction side of the Y axis). Good.

FIG. 12 is an explanatory diagram schematically showing the configuration of the air electrode side current collecting member 134 in the third modification. As shown in FIG. 12, in the base portion 136 of the air electrode side current collecting member 134, the connecting portion 137 and the cell contact portion 135 may extend from the ends on both sides of the through hole 30.

Further, the configuration of the power generation unit 102 or the fuel cell stack 100 of the above embodiment (and the modified example, the same applies hereinafter) is merely an example and can be variously modified. For example, the configurations (shape, material, etc.) of the air electrode side current collector 134 and the air electrode side spacer 139 in the above embodiment are merely examples and can be variously deformed.

Further, in the above embodiment, the interconnector 150 is covered with the coat 151, but the interconnector 150 may not be covered with the coat 151. Similarly, in the above embodiment, the air electrode side current collecting member 134 is covered with the coat 38, but the air electrode side current collecting member 134 may not be covered with the coat 38. Further, in the above embodiment, the bonding layer 138 is interposed between the air electrode side current collecting member 134 and the air electrode 114, but the bonding layer 138 is interposed between the air electrode side current collecting member 134 and the air electrode 114. May not intervene.

Further, in the above embodiment, the bolt holes 109 are provided independently of the communication holes 108 for each manifold, but the independent bolt holes 109 are not provided, and the communication holes 108 for each manifold are used as bolt holes. May also be used. Further, in the above embodiment, a counterflow type in which the main flow direction of the oxidant gas OG in the air chamber 166 and the main flow direction of the fuel gas FG in the fuel chamber 176 are substantially opposite directions will be described as an example. However, the present invention is also applicable to other types (such as a coflow type in which the two flow directions are substantially the same, a cross flow type in which the two flow directions intersect, and the like).

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, an intermediate layer may be arranged between the air electrode 114 and the electrolyte layer 112. Further, the material constituting each member in the above embodiment is merely an example, and each member may be composed of another material.

Further, in the above embodiment, the configuration of the air pole side current collecting member 134 arranged between the interconnector 150 and the air pole 114 and the air pole side spacer 139 arranged in the vicinity of the air pole side current collecting member 134 will be described. However, as for the fuel pole 116 side, a current collector and a spacer having the same configurations as those of the air pole side current collector 134 and the air pole side spacer 139 may be used. In that case, the fuel electrode 116 corresponds to the specific electrode in the claims.

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 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 a configuration. That is, the fuel cell stack 100 in the above-described embodiment may be read as an electrolytic cell stack, the power generation unit 102 may be read as an electrolytic cell unit, and the single cell 110 may be read as an electrolytic single cell. However, 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, if the current collecting member and the spacer having the same configuration as those in the above embodiment are used, the height of the gas chamber is kept constant while suppressing an increase in the weight of the current collecting member. The above can be ensured, the ease of manufacturing the current collector member can be improved, and the occurrence of cracking of the electrolytic single cell can be effectively suppressed.

22: Bolt 26: Insulation sheet 27: Gas passage member 28: Main body 29: Branch 30: Through hole 31: End 32: End 33: End 34: Wide part 38: Coat 39: Space 40: Through hole 100: Fuel cell stack 102: Fuel cell power generation unit 104: End plate 106: End plate 107: Through hole for flow path 108: Communication hole 109: Bolt hole 110: Single cell 112: Electrolyte layer 114: Air electrode 116: Fuel electrode 120: Separator 121: Hole 124: Joint 130: Air pole side frame 131: Hole 132: Oxidizing agent gas supply communication flow path 133: Oxidizing agent gas discharge communication flow path 134: Air pole side current collecting member 135: Cell contact part 136: Base part 137: Connecting part 138: Joint layer 139: Air pole side spacer 140: Fuel pole side frame 141: Hole 142: Fuel gas supply communication flow path 143: Fuel gas discharge communication flow path 144: Fuel pole side current collection Member 145: Cell contact part 146: Base part 147: Connecting part 149: Fuel electrode side spacer 150: Interconnector 151: Coat 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 FG: Fuel gas FOG: Fuel off gas OG: Oxidating agent gas OOG: Oxidating agent off gas

Claims (10)

An electrochemical reaction single cell containing an electrolyte layer and an air electrode and a fuel electrode facing each other in the first direction across the electrolyte layer.
A plate-shaped interconnector arranged on a specific electrode side of at least one of the air electrode and the fuel electrode of the electrochemical reaction single cell,
A conductive current collecting member arranged between the interconnector and the specific electrode,
In the electrochemical reaction unit with
The current collector member
A plate-shaped base portion that is in contact with the surface of the interconnector and has a through hole extending in the first direction, and a base portion.
A plurality of plate-shaped cell contact portions that are arranged so as to overlap the through holes of the base portion in the first directional view and are in contact with the surface of the specific electrode.
A connecting portion connecting the end portion of each cell contact portion and the end portion of the base portion facing the through hole,
Including
The electrochemical reaction unit further
A spacer composed of an elastic body, housed in the through hole of the base portion in the first direction, and having a shape extending from the surface of the interconnector to the surface of each cell contact portion .
The thickness of the base portion in the first direction is one tenth or more of the thickness of the electrochemical reaction single cell in the first direction.
An electrochemical reaction unit characterized by that. In the electrochemical reaction unit according to claim 1,
The boundary between each of the cell contact portions and each of the connecting portions is substantially parallel to the second direction orthogonal to the first direction.
The spacer is in contact with the inner peripheral surface of the through hole of the base portion so that movement along the second direction is restricted.
An electrochemical reaction unit characterized by that. In the electrochemical reaction unit according to claim 1 or 2.
The boundary between each of the cell contact portions and each of the connecting portions is substantially parallel to the second direction orthogonal to the first direction.
The spacer abuts on the inner peripheral surface of the through hole of the base portion so that movement along a third direction orthogonal to both the first direction and the second direction is restricted. ing,
An electrochemical reaction unit characterized by that. In the electrochemical reaction unit according to any one of claims 1 to 3.
In the first direction, a space in which the spacer does not exist is secured between the interconnector and a part of the cell contact portion on the connecting portion side.
An electrochemical reaction unit characterized by that. In the electrochemical reaction unit according to any one of claims 1 to 4.
The boundary between each of the cell contact portions and each of the connecting portions is substantially parallel to the second direction orthogonal to the first direction.
The end of each cell contact portion in the third direction orthogonal to both the first direction and the second direction, which is opposite to the boundary with the connecting portion, is viewed in the first direction. , Overlapping with the spacer,
An electrochemical reaction unit characterized by that. In the electrochemical reaction unit according to any one of claims 1 to 4.
The boundary between each of the cell contact portions and each of the connecting portions is substantially parallel to the second direction orthogonal to the first direction.
The end of each cell contact portion in the third direction orthogonal to both the first direction and the second direction, which is opposite to the boundary with the connecting portion, is viewed in the first direction. , Does not overlap with the spacer,
An electrochemical reaction unit characterized by that. In the electrochemical reaction unit according to any one of claims 1 to 6.
The boundary between each of the cell contact portions and each of the connecting portions is substantially parallel to the second direction orthogonal to the first direction.
The base portion is formed with a plurality of the through holes arranged side by side in a third direction orthogonal to both the first direction and the second direction.
The electrochemical reaction unit comprises a plurality of spaced spacers provided corresponding to the plurality of through holes.
An electrochemical reaction unit characterized by that. In the electrochemical reaction unit according to any one of claims 1 to 7.
The boundary between each of the cell contact portions and each of the connecting portions is substantially parallel to the second direction orthogonal to the first direction.
The width of each cell contact portion along the second direction is smaller than the width along the third direction orthogonal to both the first direction and the second direction.
An electrochemical reaction unit characterized by that. In the electrochemical reaction unit according to any one of claims 1 to 8.
The electrochemical reaction single cell is a fuel cell single cell.
An electrochemical reaction unit characterized by that. 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 9.

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