JP6827672B2 - Electrochemical reaction cell stack - Google Patents

Description

The techniques disclosed herein relate to electrochemical reaction cell stacks.

A solid oxide fuel cell (hereinafter referred to as "SOFC") having an electrolyte layer containing a solid oxide is known as one of the types of fuel cells that generate electricity by utilizing an electrochemical reaction between hydrogen and oxygen. Has been done. A fuel cell single cell (hereinafter, simply referred to as “single cell”), which is a constituent unit of SOFC, has an electrolyte layer and air that faces each other in a predetermined direction (hereinafter, referred to as “first direction”) across the electrolyte layer. Includes poles and fuel poles.

SOFCs are generally a structure in which a plurality of single cells are arranged side by side in the first direction (hereinafter referred to as "fuel cell block") and a pair of flat plates facing each other in the first direction with the fuel cell block interposed therebetween. It is used in the form of a fuel cell stack with members (also called "end plates"). The fuel cell stack is formed with a gas flow path (also referred to as a "manifold") that extends over the entire fuel cell block. The gas flow path is used for supplying reaction gas (oxidizing agent gas or fuel gas) to each single cell contained in the fuel cell stack and discharging off-gas from each single cell (for example, Patent Document 1). reference).

JP-A-2015-88264

In the conventional fuel cell stack configuration, the flat plate member is penetrated in the first direction at a position overlapping the gas flow path (manifold) in the first directional view on one of the pair of flat plate members (end plates). Gas holes are formed. The reaction gas is supplied to the gas flow path from a gas supply unit such as a pipe provided outside the fuel cell stack through a gas hole formed in the flat plate-shaped member. Therefore, in the above-mentioned conventional fuel cell stack configuration, there is a problem that the temperature of the reaction gas supplied to the gas flow path is not sufficiently high, and as a result, the power generation performance is not sufficiently high. Further, in the conventional configuration of the fuel cell stack, for example, when a combustor for burning off gas discharged from the fuel cell stack is provided, the fuel cell stack is arranged outside the fuel cell stack and formed on the fuel cell stack. A gas pipe or the like connecting the gas discharge port and the gas supply port formed in a member such as a combustor is required. As a result, there is a problem that the configuration of the gas pipe or the like becomes large and complicated, and the configuration of the module including the fuel cell stack and the gas pipe or the like outside the fuel cell stack becomes large and complicated.

The first direction of such a problem is that the electrolytic single cell, 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. This is also a common problem for electrolytic cell stacks having a plurality of electrolytic cell blocks arranged side by side. In the present specification, the fuel cell stack and the electrolytic cell stack are collectively referred to as an "electrochemical reaction cell stack". Moreover, such a problem is common not only to SOFC and SOEC but also to other types of electrochemical reaction cell stacks.

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 cell stack disclosed in the present specification includes an electrochemical reaction single cell containing an electrolyte layer and an air electrode and a fuel electrode facing each other in a first direction with the electrolyte layer interposed therebetween. A plurality of electrochemical reaction blocks arranged side by side in the first direction, and a plurality of flat plates arranged side by side in the first direction at a position on one side of the first direction with respect to the electrochemical reaction block. In an electrochemical reaction cell stack comprising a member and a plurality of gas flow paths extending over the electrochemical reaction block, at the one end in the first direction of the plurality of tabular members. A plurality of gas holes are formed on the outer surface, which is the surface on one side of the outer flat member, which is the located flat member, at a position not overlapping with the gas flow path in the first direction. Inside the structure composed of the plurality of flat plate-shaped members, a plurality of communicating gas flow paths for communicating the respective gas holes and the respective gas flow paths are formed, and the plurality of flat plate-shaped members Inside, on the one-sided surface in the first direction of the inner flat plate structure composed of one or more of the flat plate-like members arranged between the outer flat plate-like member and the electrochemical reaction block. A first recess forming the first communicating gas flow path in the plurality of communicating gas flow paths is formed, and the surface of the inner flat plate structure on the other side in the first direction is described. A second recess forming the second communicating gas flow path among the plurality of communicating gas flow paths is formed. In the present electrochemical reaction cell stack, the reaction gas introduced into the electrochemical reaction cell stack from the outside flows into the communicating gas flow path from the gas hole provided in the outer flat plate member, and then flows into the gas flow path. .. When the reaction gas passes through the communication gas flow path, the temperature of the reaction gas rises due to the heat from the electrochemical reaction single cell. Therefore, according to the present electrochemical reaction cell stack, the temperature of the reaction gas flowing into the gas flow path is raised as compared with the configuration in which the reaction gas directly flows into the gas flow path from the outside of the electrochemical reaction cell stack. It is possible to improve the reaction efficiency of power generation and hydrogen production. As a result, the performance of the electrochemical reaction cell stack can be improved. Further, in the present electrochemical reaction cell stack, since the communicating gas flow path is formed inside the structure composed of a plurality of flat plate-shaped members, the length of the piping outside the electrochemical reaction cell stack is shortened. be able to. As a result, it is possible to realize miniaturization and simplification of the configuration of the module including the electrochemical reaction cell stack and the gas pipe or the like outside the electrochemical reaction cell stack. Further, the first recess forming the first communicating gas flow path is formed on the surface of the inner flat plate structure on one side in the first direction, and the second recess forming the second communicating gas flow path. Is formed on the surface of the inner flat plate structure on the other side in the first direction. Therefore, compared to the case where the first recess and the second recess are formed on the same surface of the inner flat plate structure, there is a difference between the first communication gas flow path and the second communication gas flow path. It is possible to suppress gas leakage.

(2) In the electrochemical reaction cell stack, the plurality of gas flow paths include a gas flow path for supplying an oxidant gas, a gas flow path for discharging the oxidant gas, and a gas flow path for supplying fuel gas. The plurality of gas holes include a gas flow path for discharging fuel gas, a gas hole for supplying oxidant gas, a gas hole for discharging oxidant gas, and a gas hole for supplying fuel gas. A gas hole for discharging fuel gas, and one of the first communicating gas flow path and the second communicating gas flow path includes the gas hole for supplying the oxidizing agent gas. The communicating gas flow path for supplying the oxidant gas, which communicates with the gas flow path for supplying the oxidant gas, and the gas hole for discharging the oxidant gas and the gas flow path for discharging the oxidant gas are communicated with each other. The first communication gas flow path and the other communication gas flow path in the second communication gas flow path include the communication gas flow path for discharging the oxidant gas, and the other communication gas flow path is a gas hole for supplying the fuel gas. Fuel gas discharge that communicates with the fuel gas supply communication gas flow path that communicates with the fuel gas supply gas flow path, and the fuel gas discharge gas hole and the fuel gas discharge gas flow path. Of the first recess and the second recess, the recess constituting the one communicating gas flow path constitutes the communicating gas flow path for supplying the oxidizing agent gas. The recess for supplying the oxidant gas and the recess for discharging the oxidant gas constituting the communicating gas flow path for discharging the oxidant gas, and the recess for supplying the oxidant gas and the oxidant The recess for gas discharge is formed on the same surface of the inner flat plate structure, and among the first recess and the second recess, the recess constituting the other communicating gas flow path is The fuel gas includes a recess for supplying a fuel gas constituting the communicating gas flow path for supplying the fuel gas and a recess for discharging the fuel gas forming the communicating gas flow path for discharging the fuel gas. The recess for supply and the recess for discharging fuel gas may be formed on the same surface of the inner flat plate structure. According to the present electrochemical reaction cell stack, leakage between the oxidant gas and the fuel gas can be more reliably suppressed.

(3) In the electrochemical reaction cell stack, at least a part of the first recess and the second recess may overlap in the first direction. According to the present electrochemical reaction cell stack, at least one of the first recess and the second recess is secured longer than in the case where the first recess and the second recess are arranged so as not to overlap each other. , The degree of freedom of layout can be improved.

(4) In the electrochemical reaction cell stack, welding marks are formed on the outer surface of the outer flat plate member along a virtual line surrounding the first communicating gas flow path in the first directional view. It may be configured as such. According to the present electrochemical reaction cell stack, the sealing property of the communicating gas flow path can be improved, and gas leakage from the communicating gas flow path can be suppressed.

(5) In the electrochemical reaction cell stack, a rib extending along the longitudinal direction of the recess may be formed in at least one recess of the first recess and the second recess. According to this electrochemical reaction cell stack, it is possible to suppress the pressure loss of gas in the communicating gas flow path while suppressing the deformation of the recess.

(6) The electrochemical reaction cell stack may be configured to include a gas combustion unit arranged at a position on one side of the first direction with respect to the plurality of flat plate-shaped members. According to the present electrochemical reaction cell stack, the gas flowing through the first recess and the second recess can be heated by the heat from the gas fuel section. As a result, the temperature of the reaction gas flowing into the gas flow path can be raised more efficiently, and the reaction efficiency of power generation and hydrogen generation can be improved.

The techniques disclosed in the present specification can be realized in various forms, for example, an electrochemical reaction cell stack (fuel cell stack or electrolytic cell stack), an electrochemical reaction cell stack and a gas pipe, and the like. It can be realized in the form of an electrochemical reaction module provided with and a method for producing the same.

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 XY plane structure of the upper side of the fuel cell stack 100 in this embodiment. 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 YZ cross-sectional structure of the fuel cell stack 100 at the position IV-IV of FIG. It is explanatory drawing which shows the XZ cross-sectional structure of the fuel cell stack 100 at the position of VV of FIG. It is a perspective view which shows the appearance structure of each of the inner cover plate 300 and the lower end plate 106. It is explanatory drawing which shows the structure of the lower surface (XY plane) of the lower end plate 106. It is a perspective view which shows the appearance structure of each of the lower end plate 106 and the outer cover plate 200. It is explanatory drawing which shows the XZ cross-sectional structure of the outer cover plate 200 and the end plate 106 at the position of IX-IX of FIG.

A. First 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, FIG. 2 is an explanatory view showing an upper XY plane configuration of the fuel cell stack 100, and FIG. 3 is FIG. It is explanatory drawing which shows the YZ cross-sectional structure of the fuel cell stack 100 at the position of III-III, and FIG. 4 is the explanatory view which shows the YZ cross-sectional structure of the fuel cell stack 100 at the position of IV-IV of FIG. 5 is an explanatory view showing an XZ cross-sectional configuration of the fuel cell stack 100 at the position VV in FIG. 2. 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. Further, in the present specification, the direction orthogonal to the Z axis (for example, the X direction or the Y direction) is referred to as a plane direction.

As shown in FIGS. 3 to 5, the fuel cell stack 100 is installed, for example, in a heat insulating container 10 provided with a heat insulating material on the inner side surface of a housing made of stainless steel, via a support column 20.

Further, below the fuel cell stack 100, an auxiliary device 40 responsible for intake and exhaust to and from the fuel cell stack 100 is arranged. Various pipes 70 extending from the outside of the heat insulating container 10 are connected to the auxiliary device 40, and the oxidant gas OG, raw fuel gas, reformed water, and the like are introduced into the auxiliary device 40 via the pipe 70. At the same time, exhaust gas is discharged from the auxiliary device 40. Inside the auxiliary device 40, there is a reforming chamber (not shown) for reforming raw fuel gas to generate fuel gas FG, and a combustion chamber for burning off gas discharged from the fuel cell stack 100 (FIG.). Not shown) is formed. Further, various pipes 60 are provided between the auxiliary device 40 and the fuel cell stack 100, and the oxidant gas OG and the fuel gas FG are provided from the auxiliary device 40 to the fuel cell stack 100 via the pipes 60. Is introduced, and off-gas is discharged from the fuel cell stack 100 to the auxiliary device 40. The auxiliary device 40 corresponds to a gas combustion unit within the scope of claims.

As shown in FIGS. 1 to 5, the fuel cell stack 100 includes a plurality of (seven in this embodiment) fuel cell power generation unit (hereinafter, simply referred to as “power generation unit”) 102 and a pair of end plates 104, 106. The outer cover plate 200 and the inner cover plate 300 are provided. The plurality of power generation units 102 included in the fuel cell stack 100 are arranged side by side in a predetermined arrangement direction (vertical direction in this embodiment). The pair of end plates 104 and 106 are arranged so as to sandwich an aggregate (hereinafter, referred to as "power generation block 103") composed of a plurality of power generation units 102 from above and below. Further, the outer cover plate 200 is arranged below the lower end plate 106, and the inner cover plate 300 is arranged above the lower end plate 106. The arrangement direction (vertical direction) corresponds to the first direction in the claims, and the power generation block 103 corresponds to the electrochemical reaction block in the claims.

As shown in FIGS. 1, 2 and 5, a plurality of vertically penetrating peripheral portions of each power generation unit 102, each end plate 104, 106 and the inner cover plate 300 in the Z direction (the present embodiment). 8) holes are formed in each power generation unit 102, each end plate 104, 106 and the inner cover plate 300, and the corresponding holes communicate with each other in the vertical direction from one end plate 104 to the other. A fastening communication hole 108 extending in the vertical direction is formed over the end plate 106 of the above. In the following description, the holes formed in each member to form the fastening communication holes 108 may also be referred to as the fastening communication holes 108.

A bolt 22 extending in the vertical direction is inserted into each communication hole 108 for fastening, and each power generation unit 102 and each end plate 104, 106 are integrally formed by the bolt 22 and the nuts 24 fitted at both ends of the bolt 22. It has been concluded. It should be noted that between the nut 24 fitted on the upper side of each bolt 22 and the upper surface of the upper end plate 104, and the lower side of the nut 24 fitted on the lower side of each bolt 22 and the lower end plate 106. An insulating sheet 26 is interposed between the surface and the surface. 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.

Further, as shown in FIGS. 1 to 4, a plurality of holes (four in the present embodiment) penetrating in the vertical direction are formed on the peripheral edge of each power generation unit 102 in the Z direction, and each power generation is performed. Holes formed in the unit 102 and corresponding to each other communicate with each other in the vertical direction to form a communication hole 109 for a flow path extending in the vertical direction over an aggregate (power generation block 103) composed of 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 109 for the flow path may also be referred to as the communication holes 109 for the flow path.

As shown in FIGS. 1 to 3, the position is near the midpoint of one side (the side on the positive side of the Y axis among the two sides parallel to the X axis) on the outer circumference of the fuel cell stack 100 around the Z direction. The communication hole 109 for the flow path functions as an oxidant gas introduction manifold 161 which is a gas flow path for supplying the oxidant gas OG introduced into the fuel cell stack 100 to the air chamber 166 of each power generation unit 102. Specifically, the flow path communication hole 109 that functions as the oxidant gas introduction manifold 161 is formed on one side (X-axis direction) of the midpoint of the one side and the direction parallel to the side (X-axis direction). It is arranged between the nut 24 (bolt 22) located in the negative direction of the X-axis). Further, the flow path communication hole 109 located near the midpoint of the side opposite to the side (the side on the negative side of the Y axis of the two sides parallel to the X axis) is the air 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 gas discharged from the chamber 166, to the outside of the fuel cell stack 100. Specifically, the flow path communication hole 109 that functions as the oxidant gas discharge manifold 162 has a midpoint on the opposite side and one side of the midpoint in a direction parallel to the side (X-axis direction). It is arranged between the nut 24 (bolt 22) located in the (X-axis negative direction). In this embodiment, for example, air is used as the oxidant gas OG.

Further, as shown in FIGS. 1, 2 and 4, one side of the fuel cell stack 100 around the Z direction (the side on the negative side of the Y axis among the two sides parallel to the X axis). The flow path communication hole 109 located near the midpoint functions as a fuel gas introduction manifold 171 which is a gas flow path for supplying the fuel gas FG introduced into the fuel cell stack 100 to the fuel chamber 176 of each power generation unit 102. .. Specifically, the flow path communication hole 109 that functions as the fuel gas introduction manifold 171 has a midpoint of the one side and the other side (X) of the midpoint in a direction parallel to the side (X-axis direction). It is arranged between the nut 24 (bolt 22) located in the positive direction of the axis). Further, the flow path communication hole 109 located near the midpoint of the side opposite to the side (the side on the positive side of the Y-axis of the two sides parallel to the X-axis) is the fuel of each power generation unit 102. It functions as a fuel gas discharge manifold 172, which is a gas flow path for discharging the fuel off-gas FOG, which is the gas discharged from the chamber 176, to the outside of the fuel cell stack 100. Specifically, the flow path communication hole 109 that functions as the fuel gas discharge manifold 172 is the midpoint of the opposite side and the other side of the midpoint in the direction parallel to the side (X-axis direction). It is arranged between the nut 24 (bolt 22) located in the positive direction of the X-axis). In the present embodiment, for example, a hydrogen-rich gas obtained by reforming city gas is used as the fuel gas FG. Each manifold 161, 162, 171 and 172 is a gas flow path (gas flow path for supplying oxidant gas, gas flow path for discharging oxidant gas, gas flow path for supplying fuel gas) within the scope of the patent claim. , Gas flow path for fuel gas discharge).

(Structure of end plates 104, 106 and cover plates 200, 300)
The pair of end plates 104 and 106 are substantially rectangular flat plate-shaped conductive members, and are made of, for example, stainless steel. The upper end plate 104 is arranged above the power generation block 103 composed of a plurality of power generation units 102, and the lower end plate 106 is arranged below the power generation block 103. A plurality of power generation units 102 are held in a pressed state by a pair of end plates 104 and 106. In the present embodiment, 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.

The outer cover plate 200 is a flat plate-shaped conductive member, and is made of, for example, stainless steel. The outer cover plate 200 is arranged adjacent to the lower side of the lower end plate 106. The inner cover plate 300 is a flat plate-shaped conductive member, and is made of, for example, stainless steel. The inner cover plate 300 is arranged adjacent to the upper side of the lower end plate 106.

As described above, the lower end plate 106 and the cover plates 200 and 300 are located on one side (lower side) of the power generation block 103 composed of the plurality of power generation units 102 in the Z direction in the Z direction. It is a plurality of flat plate-shaped members arranged side by side. The outer cover plate 200 is a flat plate-shaped member located at one end (lower side) of the plurality of flat plate-shaped members in the Z direction, and corresponds to the outer flat plate-shaped member within the scope of claims. Further, the lower end plate 106 is a flat plate-shaped member arranged between the outer cover plate 200 and the power generation block 103 among these plurality of flat plate-shaped members, and is an inner flat plate structure within the scope of the claims. Corresponds to. The configuration of the lower end plate 106 and the cover plates 200 and 300 will be described in detail later.

(Structure of power generation unit 102)
As shown in FIGS. 3 to 5, the power generation unit 102, which is the minimum unit of power generation, includes a fuel cell single cell (hereinafter, simply referred to as “single cell”) 110, a separator 120, an air electrode side frame 130, and air. It includes a pole-side current collector 134, a fuel pole-side frame 140, a fuel pole-side current 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 above-mentioned fastening holes 108 and flow path communication holes 109 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 in the Z direction. There is. Since the power generation unit 102 includes a single cell 110, the power generation block 103 described above can also be expressed as a structure in which a plurality of single cells 110 are arranged side by side in the vertical direction.

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

The single cell 110 includes an electrolyte layer 112, an air electrode (cathode) 114 and a fuel electrode (anode) 116 facing each other in the vertical direction (arrangement direction in which the power generation units 102 are arranged) with the electrolyte layer 112 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 substantially rectangular flat plate-shaped member and contains at least Zr, and solid oxides such as YSZ (yttria-stabilized zirconia), ScSZ (scandia-stabilized zirconia), and CaSZ (calcia-stabilized zirconia). It is formed by objects. The air electrode 114 is a substantially rectangular flat plate-shaped member, and is formed of, for example, a perovskite-type oxide (for example, LSCF (lanternstrontium cobalt iron oxide), LSM (lanternstrontium manganese oxide), LNF (lantern nickel iron)). Has been done. The fuel electrode 116 is a substantially rectangular flat plate-shaped member, and is formed of, for example, Ni (nickel), a cermet composed of Ni and ceramic particles, a Ni-based alloy, or the like. As described above, the single cell 110 (power generation unit 102) of the present embodiment is a solid oxide fuel cell (SOFC) that uses a solid oxide as an electrolyte.

The separator 120 is a frame-shaped member in which a substantially rectangular hole 121 penetrating in the vertical direction is formed near the center, and is 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 joined to the single cell 110 by a joining portion formed of a brazing material (for example, Ag wax) arranged at the opposite portion thereof. The separator 120 partitions the air chamber 166 facing the air electrode 114 and the fuel chamber 176 facing the fuel electrode 116, and a gas leak from one electrode side to the other electrode side at the peripheral edge of the single cell 110. It is suppressed.

The 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. The hole 131 of the air electrode side frame 130 constitutes an air chamber 166 facing the air electrode 114. The air electrode side frame 130 is in contact with the peripheral edge of the surface of the separator 120 opposite to the side facing the single cell 110 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. As shown in FIG. 2, the air electrode side frame 130 includes an oxidant gas supply communication hole 132 that communicates the oxidant gas introduction manifold 161 and the air chamber 166, and an air chamber 166 and the oxidant gas discharge manifold 162. An oxidant gas discharge communication hole 133 that communicates with the oxidant gas is formed.

The fuel electrode side frame 140 is a frame-shaped member in which a substantially rectangular hole 141 penetrating in the vertical direction is formed near the center, and is formed of, for example, metal. Hole 141 of the fuel electrode side frame 140 constitutes a fuel chamber 176 facing the fuel electrode 116. The fuel pole side frame 140 is in contact with the peripheral edge of the surface of the separator 120 facing the single cell 110 and the peripheral edge of the surface of the interconnector 150 facing the fuel pole 116. As shown in FIG. 3, in the fuel electrode side frame 140, the fuel gas supply communication hole 142 that communicates the fuel gas introduction manifold 171 and the fuel chamber 176, and the fuel that communicates the fuel chamber 176 and the fuel gas discharge manifold 172. A gas discharge communication hole 143 is formed.

The fuel electrode side current collector 144 is arranged in the fuel chamber 176. The fuel electrode side current collector 144 is made of, for example, nickel, a nickel alloy, stainless steel, or the like. The fuel pole side current collector 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 collector 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 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. In each power generation unit 102, the fuel electrode side current collector 144 and the lower interconnector 150 may be an integral member.

The air pole side current collector 134 is arranged in the air chamber 166. The air electrode side current collector 134 is made of, for example, ferritic stainless steel. The air electrode side current collector 134 is in contact with the surface of the air electrode 114 opposite to the side facing the electrolyte layer 112 and the surface of the interconnector 150 on the side facing the air electrode 114. However, as described above, since the power generation unit 102 located at the top of the fuel cell stack 100 does not have the upper interconnector 150, the air electrode side current collector 134 in the power generation unit 102 has an upper end plate. It is in contact with 104. Since the air electrode side current collector 134 has such a configuration, the air electrode 114 and the interconnector 150 (or the end plate 104) are electrically connected. In each power generation unit 102, the air electrode side current collector 134 and the upper interconnector 150 may be an integral member.

(Structure of lower end plate 106 and cover plates 200 and 300)
FIG. 6 is a perspective view showing the appearance configurations of the inner cover plate 300 and the lower end plate 106, and FIG. 7 is an explanatory view showing the configuration of the lower surface (XY plane) of the lower end plate 106. Yes, FIG. 8 is a perspective view showing the appearance configurations of the lower end plate 106 and the outer cover plate 200, respectively. In FIG. 7, the position of the outer cover plate 200 is shown by a broken line so as to overlap the structure of the lower end plate 106.

As described above, eight fastening communication holes 108 that penetrate the lower end plate 106 in the vertical direction are formed on the peripheral edge of the lower end plate 106 in the Z direction. Further, on the upper surface of the lower end plate 106, two inner flow path recesses (grooves) 107U extending in the surface direction are formed. The upper surface of the lower end plate 106 corresponds to the surface on the other side of the inner flat plate structure in the first direction in the claims, and the inner flow path recess 107U is the second recess in the claims. Corresponds to (recess for supplying oxidant gas, recess for discharging oxidant gas).

As shown in FIGS. 2, 3, 5 to 7, the shape of the inner flow path recess 107U of the two inner flow path recesses 107U in the Z direction is the predetermined direction (Y direction). It has a linear shape extending along. One end (the end in the positive direction of the Y-axis) of the one inner flow path recess 107U is arranged at a position where it overlaps the oxidant gas introduction manifold 161 in the Z direction and communicates with the oxidant gas introduction manifold 161. doing. At the other end (end in the negative direction of the Y-axis) of the one inner flow path recess 107U, a flow path through hole 105 that penetrates the lower end plate 106 in the vertical direction is formed.

Of the two inner flow path recesses 107U, the shape of the other inner flow path recess 107U in the Z direction is a polygonal line extending in a direction intersecting the longitudinal direction of one inner flow path recess 107U while bending. The shape of. One end (the end in the negative direction of the Y-axis) of the other inner flow path recess 107U is arranged at a position where it overlaps the oxidant gas discharge manifold 162 in the Z direction and communicates with the oxidant gas discharge manifold 162. doing. At the other end (the end in the positive direction of the Y-axis) of the other inner flow path recess 107U, a flow path through hole 105 that penetrates the lower end plate 106 in the vertical direction is formed. In the Z direction, the oxidant gas introduction manifold 161 and the oxidant gas discharge manifold 162 are aligned in the direction in which the two flow path through holes 105 formed in each of the two inner flow path recesses 107U are lined up. It is almost orthogonal to the direction.

Further, ribs 178U extending along the longitudinal direction are formed in each inner flow path recess 107U. Specifically, the shape of the rib 178U formed in the one inner flow path recess 107U in the Z direction passes through the substantially central position in the lateral direction of the one inner flow path recess 107U, and It has a shape extending linearly along the longitudinal direction of the one inner flow path recess 107U. The shape of the rib 178U formed in the other inner flow path recess 107U in the Z direction passes through the substantially central position in the lateral direction of the other inner flow path recess 107U, and the other inner flow. It has a curved linear shape that extends along the longitudinal direction of the other inner flow path recess 107U while being bent so as to correspond to the shape of the road recess 107U. The height dimension of each rib 178U in the Z-axis direction may be substantially the same as the depth dimension of each inner flow path recess 107U in the Z-axis direction, or the depth of each inner flow path recess 107U in the Z-axis direction. It may be smaller than the size.

As shown in FIG. 6, the outer peripheral shape of the inner cover plate 300 in the Z direction is a substantially rectangular shape, similar to the outer peripheral shape of the lower end plate 106. Further, the inner cover plate 300 is formed with four relay holes 302 that penetrate the inner cover plate 300 in the vertical direction. The four relay holes 302 correspond to the four flow path recesses 107U and 107D formed in the lower end plate 106. As shown in FIGS. 2, 3 and 6, the two relay holes 302 corresponding to the two inner flow path recesses 107U overlap with the corresponding inner flow path recesses 107U in the Z direction, and each of them It is arranged at a position overlapping the manifolds 161, 162. When the inner cover plate 300 is arranged on the upper surface of the lower end plate 106, the portion of each inner flow path recess 107U that does not overlap with the relay hole 302 is closed by the inner cover plate 300. Therefore, a space formed by each inner flow path recess 107U is secured inside the structure composed of the inner cover plate 300 and the lower end plate 106. The two relay holes 302 corresponding to the two outer flow path recesses 107D are arranged at positions that overlap with the corresponding outer flow path recesses 107D and overlap with the respective manifolds 171 and 172 in the Z direction. Therefore, each relay hole 302 communicates with each manifold 171 and 172. A communication hole 108 for fastening is formed between a set of relay holes 302 arranged in the X-axis direction.

Further, on the lower surface of the lower end plate 106, two outer flow path recesses (grooves) 107D extending in the surface direction are formed. The lower surface of the lower end plate 106 corresponds to the surface on one side of the inner flat plate structure in the first direction in the claims, and the outer flow path recess 107D is the first recess in the claims. Corresponds to (recess for fuel gas supply, recess for fuel gas discharge).

As shown in FIGS. 2, 4, 5, 7, and 8, of the two outer flow path recesses 107D, the shape of one of the outer flow path recesses 107D in the Z direction is defined in a predetermined direction ( It has a linear shape extending along the Y direction). One end (the end in the negative direction of the Y-axis) of the one outer flow path recess 107D is arranged at a position where it overlaps with the fuel gas introduction manifold 171 in the Z direction, and the one end is on the lower side. A through hole 105 for a flow path that penetrates the end plate 106 in the vertical direction is formed. Therefore, the flow path through hole 105 formed in the outer flow path recess 107D communicates with the fuel gas introduction manifold 171 via the relay hole 302 formed in the inner cover plate 300. The other end (the end in the positive direction of the Y-axis) of the one inner flow path recess 107U overlaps with one of the four gas holes 202 described later formed in the outer cover plate 200 in the Z direction. Is located in.

Of the two outer flow path recesses 107D, the shape of the other outer flow path recess 107D in the Z direction is a polygonal line extending in a direction intersecting the longitudinal direction of one outer flow path recess 107D while bending. The shape of. One end (the end in the positive direction of the Y-axis) of the other outer flow path recess 107D is arranged at a position where it overlaps with the fuel gas discharge manifold 172 in the Z direction, and the one end is on the lower side. A through hole 105 for a flow path that penetrates the end plate 106 in the vertical direction is formed. Therefore, the flow path through hole 105 formed in the other outer flow path recess 107D communicates with the fuel gas discharge manifold 172 via the relay hole 302 formed in the inner cover plate 300. The other end (the end in the negative direction of the Y-axis) of the other outer flow path recess 107D is arranged at a position where it overlaps with one of the four gas holes 202 described later formed in the outer cover plate 200 in the Z direction. Has been done. In the Z direction, the direction in which the two flow path through holes 105 formed in each of the two outer flow path recesses 107D are aligned is the direction in which the fuel gas introduction manifold 171 and the fuel gas discharge manifold 172 are aligned. It is almost orthogonal. As shown in FIGS. 2, 5 and 7, due to the layout, when viewed through the lower end plate 106 in the Z direction, the other inner flow path recess 107U and the other outer flow flow. A part of the road recess 107D overlaps with each other, and is partitioned in the vertical direction by a lower end plate 106.

As shown in FIGS. 7 and 8, the outer peripheral shape of the outer cover plate 200 in the Z direction overlaps the outer peripheral shape of the lower end plate 106 with the fastening communication hole 108, that is, the four corners. The shape is such that a notch (external concave portion Pa) is formed at a position substantially at the center of each side. Further, the outer cover plate 200 is formed with four gas holes 202 that penetrate the outer cover plate 200 in the vertical direction. The four gas holes 202 correspond to the four flow path recesses 107U and 107D formed in the lower end plate 106. The four gas holes 202 are a plurality of gas holes (gas hole for supplying oxidant gas, gas hole for discharging oxidant gas, gas hole for supplying fuel gas, gas hole for discharging fuel gas) in the claims. ) Corresponds to.

As shown in FIGS. 2, 3 and 7, the two gas holes 202 corresponding to the two inner flow path recesses 107U are located at positions that do not overlap with the manifolds 161, 162 in the Z direction, specifically, , It is arranged at a position overlapping with the flow path through hole 105 formed in the corresponding inner flow path recess 107U. Therefore, the two gas holes 202 formed in the outer cover plate 200 communicate with the space formed by the recesses 107U for each inner flow path through the through holes 105 for the flow path.

The two gas holes 202 corresponding to the two outer flow path recesses 107D are located at positions that do not overlap with the respective manifolds 171 and 172 in the Z direction, specifically, at both ends of the corresponding outer flow path recesses 107D. Inside, it is arranged at a position overlapping the end portion where the through hole 105 for the flow path is not formed. When the outer cover plate 200 is arranged on the lower surface of the lower end plate 106, the portion of each outer flow path recess 107D that does not overlap with the gas hole 202 is closed by the outer cover plate 200. Therefore, a space formed by each outer flow path recess 107D is secured inside the structure composed of the outer cover plate 200 and the lower end plate 106. The space formed by the recesses 107U and 107D for each flow path is opened to the outside of the fuel cell stack 100 through the gas hole 202, and the corresponding manifolds 161 and 162 are opened through the through hole 105 for the flow path. It communicates with 171 and 172. That is, a communication gas flow path that communicates the gas hole 202 and each manifold 161, 162, 171 and 172 is formed by the space formed by the recesses 107 for each flow path. Hereinafter, the communicating gas flow path communicating with the oxidant gas introduction manifold 161 is referred to as an oxidant gas introduction communication flow path 163, and the communicating gas flow path communicating with the oxidant gas discharge manifold 162 is referred to as an oxidant gas discharge communication flow path. The communication gas flow path that communicates with the fuel gas introduction manifold 171 is referred to as fuel gas introduction communication flow path 173, and the communication gas flow path that communicates with the fuel gas discharge manifold 172 is referred to as fuel gas discharge communication flow path 174. .. The fuel gas introduction communication flow path 173 and the fuel gas discharge communication flow path 174 are the first communication gas flow paths (the communication gas flow path for supplying fuel gas and the communication gas flow for fuel gas discharge) within the scope of the patent claim. The oxidant gas introduction communication flow path 163 and the oxidant gas discharge communication flow path 164 correspond to the second communication gas flow path (communication gas flow path for supplying the oxidant gas, oxidation) within the scope of the patent claim. Corresponds to a continuous gas flow path for discharging agent gas).

As shown in FIG. 3, a pipe 60 for introducing the oxidant gas OG from the auxiliary device 40 is connected to the oxidant gas introduction communication flow path 163, and the oxidant gas discharge communication flow path 164 is connected to the oxidant gas discharge communication flow path 164. A pipe 60 for discharging the oxidant off-gas OOG to the auxiliary device 40 is connected. Further, as shown in FIG. 4, a pipe 60 for introducing fuel gas FG from the auxiliary device 40 is connected to the fuel gas introduction communication flow path 173, and fuel is connected to the fuel gas discharge communication flow path 174. A pipe 60 for discharging the off-gas FOG to the auxiliary device 40 is connected.

As shown in FIGS. 7 and 8, the outer cover plate 200 is welded to the lower end plate 106. More specifically, on the lower surface of the outer cover plate 200, an outer peripheral welding mark 220 that joins the outer cover plate 200 and the lower end plate 106 along the vicinity of the outer peripheral line OL of the outer cover plate 200 in the Z direction. Is formed. Further, on the lower surface of the outer cover plate 200, a welding mark for the flow path that joins the outer cover plate 200 and the lower end plate 106 along the virtual line VL surrounding each flow path recess 107 in the Z direction. 210 is formed. As a result, the communication gas flow path formed by the recesses 107 for each flow path (oxidizer gas introduction communication flow path 163, oxidizer gas discharge communication flow path 164, fuel gas introduction communication flow path 173, fuel gas discharge communication flow path). The sealing property of the road 174) is enhanced. The flow path welding mark 210 corresponds to a welding mark within the scope of the claims.

As shown in FIG. 9, which shows the XZ cross-sectional configuration of the position of IX-IX in FIG. 7, a welding recess 230 is formed on the lower surface (Z-axis negative direction side) of the outer cover plate 200, and the outer circumference is formed. The welding mark 220 and the welding mark 210 for the flow path are formed in the welding recess 230. Further, the outer peripheral welding mark 220 and the flow path welding mark 210 are separated from the side surface of the welding recess 230. As shown in FIG. 6, the inner cover plate 300 may also be joined to the lower end plate 106 by welding in the same manner as the outer cover plate 200.

A-2. Operation of fuel cell stack 100:
As shown in FIG. 3, the oxidant gas OG introduced into the auxiliary device 40 via the external pipe 70 of the heat insulating container 10 is oxidized provided in the fuel cell stack 100 from the auxiliary device 40 via the pipe 60. It is introduced into the agent gas introduction communication flow path 163. The oxidant gas OG introduced into the oxidant gas introduction communication flow path 163 is supplied to the oxidant gas introduction manifold 161 from the oxidant gas introduction communication flow path 163, and the oxidizer gas introduction manifold 161 oxidizes each power generation unit 102. It is supplied to the air chamber 166 through the agent gas supply communication hole 132. Further, as shown in FIG. 4, when the raw material fuel gas or reformed water is introduced into the auxiliary device 40 via the pipe 70 outside the heat insulating container 10, the raw material fuel gas is modified in the reforming chamber of the auxiliary device 40. The quality of the fuel gas FG is generated, and the generated fuel gas FG is introduced into the fuel gas introduction communication flow path 173 provided in the fuel cell stack 100 via the pipe 60. The fuel gas FG introduced into the fuel gas introduction communication flow path 173 is supplied to the fuel gas introduction manifold 171 from the fuel gas introduction communication flow path 173, and is supplied from the fuel gas introduction manifold 171 to the fuel gas supply communication hole 142 of each power generation unit 102. It is supplied to the fuel chamber 176 via.

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 (or the upper end plate 104) via the air pole side current collector 134, and the fuel pole 116 is the fuel pole. It is electrically connected to the other interconnector 150 (or the lower end plate 106) via the side current collector 144. 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. (Not shown) may be heated.

As shown in FIG. 3, the oxidant off-gas OOG discharged from the air chamber 166 to the oxidant gas discharge manifold 162 through the oxidant gas discharge communication hole 133 of each power generation unit 102 is oxidized from the oxidant gas discharge manifold 162. It is discharged to the agent gas discharge communication flow path 164, and is discharged from the oxidant gas discharge communication flow path 164 to the auxiliary device 40 via an external pipe 60 of the fuel cell stack 100. Further, as shown in FIG. 4, the fuel off-gas FOG discharged from the fuel chamber 176 to the fuel gas discharge manifold 172 through the fuel gas discharge communication hole 143 of each power generation unit 102 discharges fuel gas from the fuel gas discharge manifold 172. It is discharged to the communication flow path 174, and is discharged from the fuel gas discharge communication flow path 174 to the auxiliary device 40 via the external pipe 60 of the fuel cell stack 100. The oxidant off-gas OOG and the fuel off-gas FOG discharged to the auxiliary device 40 are mixed and burned in the fuel chamber provided in the auxiliary device 40, and are discharged to the outside of the heat insulating container 10 via the pipe 70.

A-3. Effect of this embodiment:
As described above, in the fuel cell stack 100 of the present embodiment, the power generation block 103 in which a plurality of single cells 110 (power generation unit 102) are arranged side by side in the vertical direction and one side in the vertical direction with respect to the power generation block 103 ( At the position (lower side), an end plate 106 and cover plates 200 and 300, which are a plurality of flat plate-like members arranged side by side in the vertical direction, are provided. Further, the fuel cell stack 100 is formed with manifolds 161, 162, 171 and 172, which are gas flow paths extending over the power generation block 103. Further, among the plurality of flat plate-shaped members, the end plate 106 and the cover plates 200, 300, the outer cover plate 200 (outer flat plate-shaped), which is a flat plate-shaped member located at one end (lower side) in the vertical direction. On the surface (outer surface) of the one side (lower side) of the member), gas holes 202 are formed at positions that do not overlap with the manifolds 161, 162, 171 and 172 in the Z direction. Further, inside the structure composed of the plurality of flat plate-shaped members (end plate 106 and cover plates 200, 300), a gas hole 202 provided on the lower surface of the outer cover plate 200 and each manifold 161, 162, 171 , 172 and each communication gas flow path (oxidizer gas introduction communication flow path 163, oxidizer gas discharge communication flow path 164, fuel gas introduction communication flow path 173, fuel gas discharge communication flow path 174) are formed. There is. Therefore, in the fuel cell stack 100 of the present embodiment, the oxidant gas OG and the fuel gas FG introduced into the fuel cell stack 100 via the pipe 60 are introduced from the gas holes 202 provided on the lower surface of the outer cover plate 200. It flows into each communication gas flow path (oxidizer gas introduction communication flow path 163 and fuel gas introduction communication flow path 173) formed inside the structure composed of the end plate 106 and the cover plates 200 and 300, and then flows into the communication flow path. It flows into each manifold (oxidizer gas introduction manifold 161 and fuel gas introduction manifold 171). As described above, since the power generation reaction in each single cell 110 is an exothermic reaction, when the oxidant gas OG and the fuel gas FG pass through the respective communication gas flow paths 163 and 173, the heat from the single cell 110 is generated. The temperature of the oxidant gas OG and the fuel gas FG rises. Therefore, according to the fuel cell stack 100 of the present embodiment, each manifold 161 is compared with a configuration in which the oxidant gas OG and the fuel gas FG directly flow into the manifolds 161 and 171 from the outside of the fuel cell stack 100. The temperature of the oxidant gas OG and the fuel gas FG flowing into 171 can be raised, and the temperature of the single cell 110 is lowered by the oxidant gas OG and the fuel gas FG which are directly supplied from the outside and have a relatively low temperature. Can be suppressed. As a result, the reaction efficiency of power generation in each single cell 110 can be improved, and as a result, the power generation performance of the fuel cell stack 100 can be improved.

Further, in the fuel cell stack 100 of the present embodiment, since each communicating gas flow path 163, 164, 173, 174 is formed inside the structure composed of the end plate 106 and the cover plates 200, 300, the fuel The length of the external pipe 60 of the battery stack 100 can be shortened. As a result, it is possible to suppress a decrease in the temperature of the oxidant gas OG and the fuel gas FG that have passed through the auxiliary device 40. Further, it is possible to realize miniaturization and simplification of the configuration of a module including the fuel cell stack 100 and an external gas pipe or the like of the fuel cell stack 100. Further, since the length of the external pipe 60 of the fuel cell stack 100 is short, it is suppressed that the temperatures of the oxidant off-gas OOG and the fuel off-gas FOG discharged from the fuel cell stack 100 are lowered, so that the oxidant-off gas OOG is suppressed. And the fuel off-gas FOG can be efficiently burned in the auxiliary device 40.

Further, the fuel cell stack 100 of the present embodiment is composed of a flat plate-shaped member other than the outer flat plate-shaped member, the outer cover plate 200, among the plurality of flat plate-shaped members, the end plate 106 and the outer cover plate 200. On one side (lower side) of the inner flat plate structure (that is, the end plate 106), a flow path recess 107 constituting each communication gas flow path 163, 164, 173, 174 is formed, and an outer cover plate is formed. The gas hole 202 of the 200 is arranged at a position where it overlaps with the corresponding flow path recess 107 in the Z direction, and the portion of the flow path recess 107 that does not overlap with the gas hole 202 is closed by the outer cover plate 200. ing. Therefore, according to the fuel cell stack 100 of the present embodiment, each communicating gas flow path is inside the structure composed of the outer cover plate 200 and the end plate 106 while suppressing the increase in the thickness of the outer cover plate 200. 163,164,173,174 can be formed.

Moreover, in the fuel cell stack 100 of the present embodiment, the first communication gas flow path (fuel gas introduction communication flow path 173 and fuel gas discharge communication flow path 174) used for supplying the fuel gas FG and discharging the fuel off gas FOG. ) Is formed on the surface (lower surface) on one side of the inner flat plate structure (lower end plate 106). Further, a second communication gas flow path (oxidizer gas introduction communication flow path 163 and) which is formed independently of the first communication gas flow path and is used for supplying the oxidant gas OG and discharging the oxidant off-gas OOG. The inner flow path recess 107U constituting the oxidant gas discharge communication flow path 164) is formed on the other surface (upper surface) of the inner flat plate structure. Therefore, compared with the case where the recess for the flow path forming the first communication gas flow path and the recess for the flow path forming the second communication gas flow path are formed on the same surface of the inner flat plate structure. Therefore, it is possible to suppress gas leakage between the first communication gas flow path and the second communication gas flow path.

Further, as described above, in the present embodiment, the inner flow path recess 107U and the outer flow path recess 107D are formed on the surfaces (upper surface and lower surface) located opposite to each other on the end plate 106, respectively. Therefore, even if the inner flow path recess 107U and the outer flow path recess 107D are arranged so as to overlap each other when viewed through the end plate 106 in the Z direction (FIGS. 2 and 5). And FIG. 7), it is possible to suppress the occurrence of gas leakage between the inner flow path recess 107U and the outer flow path recess 107D. Therefore, as compared with the case where the inner flow path recess 107U and the outer flow path recess 107D are arranged so as not to overlap, at least one of the inner flow path recess 107U and the outer flow path recess 107D is secured longer. , The degree of freedom in the layout of the flow path recess 107 in the end plate 106 can be improved.

Further, in the fuel cell stack 100 of the present embodiment, a welding mark 210 for the flow path is formed on the lower surface of the outer cover plate 200 along the virtual line VL surrounding each communicating gas flow path 173, 174 in the Z direction. There is. Therefore, according to the fuel cell stack 100 of the present embodiment, the sealing performance of each of the communicating gas flow paths 173 and 174 can be improved, and gas leakage from each of the communicating gas flow paths 173 and 174 can be suppressed.

Further, in the fuel cell stack 100 of the present embodiment, the welding recess 230 is formed on the lower surface of the outer cover plate 200, and the flow path welding mark 210 is formed in the welding recess 230. Therefore, according to the fuel cell stack 100 of the present embodiment, it is possible to prevent the flow path welding marks 210 from protruding from the lower surface of the outer cover plate 200. Similarly, in the fuel cell stack 100 of the present embodiment, since the outer peripheral welding mark 220 is also formed in the welding recess 230, it is possible to prevent the outer peripheral welding mark 220 from protruding from the lower surface of the outer cover plate 200. it can.

Ribs 178U and 178D extending along the longitudinal direction of the flow path recess 107 are formed in each flow path recess 107. As a result, the portion of the end plate 106 that is thinned by forming the flow path recess 107 is reinforced, so that the deformation of the portion is suppressed and the gas in each communicating gas flow path is suppressed. Pressure loss can be suppressed.

Further, the oxidant gas introduction communication flow path 163, the oxidizer gas discharge communication flow path 164, the fuel gas introduction communication flow path 173, and the fuel gas discharge communication flow path 174 are arranged between the power generation block 103 and the auxiliary device 40. ing. Thereby, the gas flowing through each communication gas flow path 163, 164, 173, 174 can be heated more effectively by the heat from the auxiliary device 40.

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 fuel cell stack 100 in the above embodiment is merely an example and can be variously modified. For example, in the above embodiment, it is said that each communication gas flow path 163, 164, 173, 174 is formed by forming the flow path recess 107 in the end plate 106, but instead of the end plate 106 or , In addition to the end plate 106, a similar flow path recess is formed in a flat plate-shaped member other than the end plate 106 (for example, a terminal plate arranged between the power generation block 103 and the end plate 106) to communicate with each other. Gas channels 163,164,173,174 may be formed.

Further, in the above embodiment, it is assumed that each communicating gas flow path 163, 164, 173, 174 is formed inside a structure composed of three flat plate-shaped members, an end plate 106 and a cover plate 200, 300. However, each communicating gas flow path 163, 164, 173, 174 may be formed inside a structure composed of two or four or more flat plate-shaped members. For example, in the above embodiment, the end plate 106 is composed of a plurality of flat plate-shaped members, and each communicating gas is inside a structure composed of the plurality of flat plate-shaped members constituting the end plate 106 and the cover plates 200 and 300. Channels 163, 164, 173, 174 may be formed. In this case, a through hole in the vertical direction is formed in one or more of the plurality of flat plate-shaped members constituting the end plate 106, and the side of the through hole facing the power generation block 103 constitutes the end plate 106. The through hole may function as each communicating gas flow path 163,164,173,174 by being closed by another flat member.

Further, in the above embodiment, the outer flow path recess 107D is formed on the surface of one flat plate-shaped member (end plate 106) on one side in the first direction, and the surface on the other side in the first direction. Although it is said that the inner flow path recess 107U is formed in the inner flow path, the outer flow path recess 107D is formed on the surface of one side of the inner flat plate structure composed of a plurality of flat plate-like members, and the other side is formed. The inner flow path recess 107U may be formed on the surface of the above. Further, for example, in the above embodiment, when the inner flat plate structure is composed of a plurality of flat plate-shaped members, two outer flow path recesses 107D may be formed on one side surface of the flat plate-shaped members different from each other. The two inner flow path recesses 107U may be formed on the other surface of the flat plate-like members different from each other.

Further, in the above embodiment, four flow path recesses 107 corresponding to each of the four gas flow paths (manifolds 161, 162, 171 and 172) are formed in the inner flat plate structure. A flow path recess 107 corresponding to at least one gas flow path of the four gas flow paths is formed on the surface of one side of the inner flat plate structure in the first direction, and the other side in the first direction is formed. It suffices that a flow path recess 107 corresponding to at least one other gas flow path is formed on the surface. For example, in the above embodiment, one of the four gas holes 202 is arranged at a position where it overlaps with the oxidant gas discharge manifold 162 in the Z direction, and the end plate 106 has an oxidant gas discharge manifold 162. The inner flow path recess 107U corresponding to the above may not be formed. Further, the other one of the four gas holes 202 is arranged at a position where it overlaps with the fuel gas discharge manifold 172 in the Z direction, and the end plate 106 has an inner flow corresponding to the fuel gas discharge manifold 172. The road recess 107U may not be formed. According to these configurations, the temperatures of the oxidant gas OG and the fuel gas FG flowing into the manifolds 161 and 171 can be raised, and the reaction efficiency of power generation in each single cell 110 can be improved, and as a result. , The power generation performance of the fuel cell stack 100 can be improved. Further, in the inner flat plate structure, the outer flow path recess 107D corresponding to the oxidant gas introduction manifold 161 is formed on the surface on one side thereof, and the oxidant gas discharge manifold 162 is supported on the surface on the other side. The inner flow path recess 107U may be formed. As a result, leakage between the gas flow path for supplying the oxidant gas OG and the gas flow path for discharging the oxidant off-gas OOG can be suppressed.

In the above embodiment, the length of one inner flow path recess 107U and the length of one outer flow path recess 107D are the same, but they may be different from each other. Further, although the length of the other inner flow path recess 107U and the length of the other outer flow path recess 107D are the same, they may be different from each other. For example, the length of the outer flow path recess 107D to which the fuel gas FG is supplied may be made longer than the length of the inner flow path recess 107U to which the oxidant gas OG is supplied to further warm the fuel gas FG. Good.

In the above embodiment, it is assumed that the inner flow path recess 107U and the outer flow path recess 107D partially overlap each other in the Z direction, but the inner flow path recess 107U and the outer flow path recess 107D are different from each other. , They may not overlap each other in the Z direction. However, as described in, for example, International Publication No. 2016/63157, a fuel cell including a heat exchange section in which a heat exchange flow path for flowing an oxidant gas for heat exchange is formed between power generation units. In a stack, multiple gas channels are complicated. Therefore, it becomes difficult to form a channel recess in the inner flat plate structure so that the communicating gas flow path communicating with each gas flow path does not communicate with each other. In such a case, the present invention is applied, and further, the flow path recess formed on one surface and the flow path recess formed on the other surface of the inner flat plate structure overlap in the Z direction. By arranging in such a manner, it is possible to improve the degree of freedom in the arrangement layout of the flow path recesses in the inner flat plate structure.

In the above embodiment, the inner cover plate 300 is arranged between the power generation block 103 and the end plate 106, but there is no inner cover plate 300 and the power generation block 103 and the end plate 106 are arranged so as to be adjacent to each other. It may be. In this case, for example, the interconnector 150 located at one end of the power generation block 103 may also function as the inner cover plate 300.

Further, at least a part of each communication gas flow path 163, 164, 173, 174 may be formed on the upper side of the fuel cell stack 100. For example, a cover plate may be arranged on the upper surface of the upper end plate 104, and a communicating gas flow path may be formed inside a structure composed of the upper end plate 104 and the cover plate. Further, it is not necessary that all of the communication gas flow paths 163, 164, 173, and 174 are formed in the fuel cell stack 100, and at least one communication gas flow path may be formed.

Further, in the above embodiment, the flow path communication hole 109 is provided separately from the fastening communication hole 108, but at least one of the fastening communication holes 108 provided in the fuel cell stack 100 is for the flow path. It may also function as a communication hole 109.

Further, in the above embodiment, it is assumed that the entire flow path welding mark 210 and the outer peripheral welding mark 220 are formed in the welding recess 230, but only a part of the flow path welding mark 210 and the outer peripheral welding mark 220 is formed. It may be formed in the welding recess 230.

Further, in the above embodiment, at least one of the flow path welding mark 210 and the outer peripheral welding mark 220 may not be formed. Further, in the above embodiment, the welding recess 230 may not be formed on the outer cover plate 200.

Further, in the above embodiment, the shape of the outer cover plate 200 or the like described using the virtual line VL is not essential and can be variously deformed.

In the above embodiment, the shape of the ribs 178U and 178D in the Z direction may not be along the longitudinal direction of the corresponding flow path recess 107. Further, the rib may not be formed in at least one of the four flow path recesses 107.

Further, in the above embodiment, the number of power generation units 102 (single cell 110) included in the fuel cell stack 100 is only an example, and the number of power generation units 102 (single cell 110) is required for the fuel cell stack 100. It is appropriately determined according to the output voltage and the like. Further, in the above embodiment, between one power generation unit 102 and another power generation unit 102, a layer having no power generation function and having conductivity (for example, a layer for securing a gas flow path in the plane direction). May intervene. Even in this case, the structure in the range from the uppermost power generation unit 102 to the lowest power generation unit 102 (that is, including the layer having no power generation function and having conductivity) is the power generation block 103. ..

Further, the material forming each member in the above embodiment is merely an example, and each member may be formed of another material. For example, the cover plates 200 and 300 and the end plate 106 may be made of the same material.

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

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 single cell, which is a constituent unit of a solid oxide fuel cell (SOEC) that generates hydrogen by utilizing it, and an electrolytic cell stack including a plurality of electrolytic single cells. 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 flow path communication hole 109 is used. Water vapor as a raw material gas is supplied through. 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 flow path communication hole 109. Even in the electrolytic cell stack having such a configuration, if the configuration is the same as that of the above embodiment, the same operation and effect as that of the above embodiment can be obtained.

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

10: Insulation container 20: Support 22: Bolt 24: Nut 26: Insulation sheet 40: Auxiliary device 60, 70: Piping 100: Fuel cell stack 102: Power generation unit 103: Power generation block 104, 106: End plate 105: For flow path Through hole 107: Recess for flow path 107D: Recession for outer flow path 107U: Recession for inner flow path 108: Communication hole for fastening 109: Communication hole for flow path 110: Single cell 112: Electrolyte layer 114: Air electrode 116: Fuel Pole 120: Separator 121: Hole 130: Air pole side frame 131: Hole 132: Oxidizing agent gas supply communication hole 133: Oxidizing gas discharge communication hole 134: Air pole side current collector 140: Fuel pole side frame 141: Hole 142 : Fuel gas supply communication hole 143: Fuel gas discharge communication hole 144: Fuel electrode side current collector 150: Interconnector 161: Oxidizing agent gas introduction manifold 162: Oxidizing agent gas discharge manifold 163: Oxidizing agent gas introduction communication flow path 164: Oxidizing agent gas discharge communication flow path 166: Air chamber 171: Fuel gas introduction manifold 172: Fuel gas discharge manifold 173: Fuel gas introduction communication flow path 174: Fuel gas discharge communication flow path 176: Fuel chamber 178U, 178D: Rib 200: Outer cover plate 202: Gas hole 210: Welding mark for flow path 220: Outer peripheral welding mark 230: Welding recess 300: Inner cover plate 302: Relay hole FG: Fuel gas FOG: Fuel off gas OG: Oxidating agent gas OL: Outer line OOG: Oxidizing agent off gas Pa: External recess VL: Virtual line

Claims (6)

An electrochemical reaction block in which a plurality of electrochemical reaction single cells including an electrolyte layer and an air electrode and a fuel electrode facing each other in the first direction across the electrolyte layer are arranged side by side in the first direction.
A plurality of flat plate-shaped members arranged side by side in the first direction at a position on one side of the first direction with respect to the electrochemical reaction block.
In an electrochemical reaction cell stack in which a plurality of gas flow paths extending over the electrochemical reaction block are formed.
The outer surface of the outer flat plate member, which is the outer flat plate member located at the one end of the plurality of flat plate members in the first direction, has the first surface on the outer surface. A plurality of gas holes are formed at positions that do not overlap with the gas flow path in the directional view.
Inside the structure composed of the plurality of flat plate-shaped members, a plurality of communicating gas flow paths for communicating the gas holes and the gas flow paths are formed.
Among the plurality of flat plate-shaped members, the inner flat plate structure composed of one or a plurality of the flat plate-shaped members arranged between the outer flat plate-shaped member and the electrochemical reaction block in the first direction. On the surface on one side thereof, a first recess forming the first communicating gas flow path among the plurality of communicating gas flow paths is formed.
The first person direction other side of the surface of the said inner flat structure, that the second recess constituting the second communicating gas flow path of the plurality of communication gas channel is formed It features an electrochemical reaction cell stack. In the electrochemical reaction cell stack according to claim 1,
The plurality of gas flow paths include a gas flow path for supplying oxidant gas, a gas flow path for discharging oxidant gas, a gas flow path for supplying fuel gas, and a gas flow path for discharging fuel gas. Including
The plurality of gas holes include a gas hole for supplying an oxidant gas, a gas hole for discharging the oxidant gas, a gas hole for supplying the fuel gas, and a gas hole for discharging the fuel gas.
One of the first communicating gas flow path and the second communicating gas flow path has a gas hole for supplying the oxidant gas and a gas flow path for supplying the oxidant gas. The communicating gas flow path for supplying the oxidant gas and the communication gas flow path for discharging the oxidant gas communicating with the gas hole for discharging the oxidant gas and the gas flow path for discharging the oxidant gas. Including
The first communicating gas flow path and the other communicating gas flow path in the second communicating gas flow path communicate the gas hole for supplying the fuel gas and the gas flow path for supplying the fuel gas. Includes a communicating gas flow path for supplying fuel gas and a communicating gas flow path for discharging fuel gas that communicates the gas hole for discharging the fuel gas and the gas flow path for discharging the fuel gas.
Of the first recess and the second recess, the recesses constituting one of the communicating gas flow paths are the recesses for supplying the oxidant gas and the recesses forming the communicating gas flow path for supplying the oxidant gas. The recess for discharging the oxidant gas, which constitutes the communicating gas flow path for discharging the oxidant gas, and the recess for supplying the oxidant gas and the recess for discharging the oxidant gas are inside the same. It is formed on the same surface in the flat plate structure and
Among the first recess and the second recess, the recesses constituting the other communicating gas flow path are the recess for supplying fuel gas forming the communicating gas flow path for supplying fuel gas and the recess for supplying fuel. The recess for discharging fuel gas including the recess for discharging fuel gas constituting the communicating gas flow path for discharging gas, and the recess for supplying fuel gas and the recess for discharging fuel gas are the same in the inner flat plate structure. An electrochemical reaction cell stack characterized by being formed on the surface. In the electrochemical reaction cell stack according to claim 1 or 2.
An electrochemical reaction cell stack, characterized in that at least a part of the first recess and the second recess overlap in the first directional view. In the electrochemical reaction cell stack according to any one of claims 1 to 3.
An electrochemical reaction characterized in that a welding mark is formed on the outer surface of the outer flat plate member along an imaginary line surrounding the first communicating gas flow path in the first directional view. Cell stack. In the electrochemical reaction cell stack according to any one of claims 1 to 4.
An electrochemical reaction cell stack, wherein at least one of the first recess and the second recess is formed with ribs extending along the longitudinal direction of the recess. In the electrochemical reaction cell stack according to any one of claims 1 to 5.
An electrochemical reaction cell stack comprising a gas combustion unit arranged at a position on one side of the plurality of flat plate-shaped members in the first direction.

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