JP2018098001A - Electrochemical reaction cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve performance of an electrochemical reaction cell stack.SOLUTION: An electrochemical reaction cell stack comprises: an electrochemical reaction block in which a plurality of electrochemical reaction unit cells are arranged in a first direction; and a plurality of plate-like members arranged in one direction side of the first direction to the electrochemical reaction block. A plurality of gas flowing passages are formed in the electrochemical reaction cell stack. In an external side surface in an external flat-plane like member positioned at an edge of the one direction in the plurality of flat-plane like members, a gas hole is formed at a position not overlapped with the gas flowing passage in a first direction view. In an inner part of a structure constructed by the plurality of flat-plane like members, a communication gas flowing passage that communicates the gas hole with the gas flowing passage is formed. In a front surface of one direction in an inner flat-plane like member arranged between the external side flat-plane like member and the electrochemical reaction block, a first concave part constructing a first communication gas flowing passage is formed. In the front surface of the other direction, a second concave part constructing a second communication gas flowing passage is formed.SELECTED DRAWING: Figure 2

Description

  The technology disclosed herein relates to an electrochemical reaction cell stack.

  One type of fuel cell that generates electricity using an electrochemical reaction between hydrogen and oxygen is a solid oxide fuel cell (hereinafter referred to as “SOFC”) having an electrolyte layer containing a solid oxide. It has been. 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 facing each other in a predetermined direction (hereinafter referred to as “first direction”) across the electrolyte layer. Electrode and fuel electrode.

  The SOFC is generally a structure in which a plurality of single cells are arranged in the first direction (hereinafter referred to as “fuel cell block”), and a pair of flat plates facing each other in the first direction across the fuel cell block. It is used in the form of a fuel cell stack comprising members (also referred to as “end plates”). In the fuel cell stack, a gas flow path (also referred to as a “manifold”) extending over the entire fuel cell block is formed. The gas flow path is used for supplying a reaction gas (oxidant gas or fuel gas) to each single cell included in the fuel cell stack and discharging off-gas from each single cell (for example, Patent Document 1). reference).

Japanese Patent Laying-Open No. 2015-88264

  In the configuration of the conventional fuel cell stack, the flat plate member penetrates in the first direction at a position overlapping one of the pair of flat plate members (end plates) in the first direction as viewed in the first direction. Gas holes are formed. The reaction gas is supplied from a gas supply unit such as a pipe provided outside the fuel cell stack to the gas flow path through a gas hole formed in the flat plate member. Therefore, the configuration of the conventional fuel cell stack has 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 configuration of the conventional 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 disposed outside the fuel cell stack and formed in the fuel cell stack. Gas piping etc. which connect a gas exhaust port and the gas supply port formed in members, such as a combustor, are needed. As a result, there is a problem in that the configuration of the gas piping and the like is increased in size and complexity, and the configuration of the module including the fuel cell stack and the gas piping outside the fuel cell stack is increased in size and complexity.

  Note that such a problem is that an electrolytic single cell, which is a constituent unit of a solid oxide electrolytic cell (hereinafter referred to as “SOEC”) that generates hydrogen using an electrolysis reaction of water, is in the first direction. This is also a problem common to electrolytic cell stacks including a plurality of electrolytic cell blocks arranged side by side. In this specification, the fuel cell stack and the electrolytic cell stack are collectively referred to as “electrochemical reaction cell stack”. Such a problem is not limited to SOFC and SOEC, but is common to other types of electrochemical reaction cell stacks.

  In this specification, the technique which can solve the subject mentioned above is disclosed.

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

(1) An electrochemical reaction cell stack disclosed in the present specification includes an electrochemical reaction unit 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. A plurality of electrochemical reaction blocks arranged side by side in a first direction, and a plurality of flat plate shapes 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 An electrochemical reaction cell stack in which a plurality of gas flow paths extending across the electrochemical reaction block are formed, at one end in the first direction of the plurality of plate-shaped members. A plurality of gas holes are formed in the outer surface which is the one surface of the outer flat plate member which is the flat plate member so as not to overlap the gas flow path when viewed in the first direction. A plurality of communication gas flow paths that communicate the gas holes and the gas flow paths are formed inside the structure constituted by the plurality of flat plate members. On the surface of the one side in the first direction in the inner flat plate structure constituted by one or a plurality of the flat plate members arranged between the outer flat plate member and the electrochemical reaction block, A first recess that constitutes a first communication gas channel among the plurality of communication gas channels is formed, and the surface of the other side in the first direction of the inner plate structure is the A second recess that constitutes a second communication gas channel among the plurality of communication gas channels is formed. In this electrochemical reaction cell stack, the reaction gas introduced into the electrochemical reaction cell stack from the outside flows into the communication gas channel from the gas hole provided in the outer flat plate member, and then flows into the gas channel. . When the reaction gas passes through the communication gas flow path, the temperature of the reaction gas rises due to 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 increased as compared with the configuration in which the reaction gas flows directly into the gas flow path from the outside of the electrochemical reaction cell stack. And the reaction efficiency of power generation and hydrogen generation can be improved. As a result, the performance of the electrochemical reaction cell stack can be improved. Moreover, in this electrochemical reaction cell stack, since the communication gas flow path is formed inside the structure constituted by a plurality of flat plate-like members, the length of the piping outside the electrochemical reaction cell stack is shortened. be able to. As a result, it is possible to reduce the size and simplify the configuration of the module including the electrochemical reaction cell stack and the gas piping outside the electrochemical reaction cell stack. Moreover, the 1st recessed part which comprises a 1st communicating gas flow path is formed in the surface of the one side of the 1st direction of an inner side plate structure, and the 2nd recessed part which comprises a 2nd communicating gas flow path Is formed on the surface of the other side in the first direction of the inner flat plate structure. For this reason, compared with the case where the 1st crevice and the 2nd crevice are formed on the same surface of an inner side plate constituent object, it is between the 1st communication gas channel and the 2nd communication gas channel. Gas leakage can be suppressed.

(2) In the electrochemical reaction cell stack, the plurality of gas passages include an oxidant gas supply gas passage, an oxidant gas discharge gas passage, and a fuel gas supply gas passage. A gas flow path for discharging a fuel gas, and the plurality of gas holes include a gas hole for supplying an oxidant gas, a gas hole for discharging an oxidant gas, and a gas hole for supplying a fuel gas, A gas hole for discharging a fuel gas, and one of the first communication gas flow path and the second communication gas flow path is formed of a gas hole for supplying the oxidant gas. An oxidant gas supply communication gas channel that communicates with the oxidant gas supply gas channel, an oxidant gas discharge gas hole, and an oxidant gas discharge gas channel that communicate with each other. A communication gas flow path for discharging the oxidant gas, and the first communication gas flow path and the second communication gas. The other communication gas flow path among the flow paths is a fuel gas supply communication gas flow path that connects the fuel gas supply gas hole and the fuel gas supply gas flow path, and the fuel gas discharge. A communication gas flow path for discharging fuel gas that communicates the gas hole for fuel and the gas flow path for discharging the fuel gas, and the one communication gas among the first recess and the second recess The recesses constituting the flow path are the oxidant gas supply recesses constituting the oxidant gas supply communication gas flow path and the oxidant gas discharges constituting the oxidant gas discharge communication gas flow path. And the oxidant gas supply recess and the oxidant gas discharge recess are formed on the same surface of the inner flat plate structure, and the first recess and Of the second recesses, the recesses constituting the other communication gas flow path are: A fuel gas supply recess that forms the communication gas flow path for supplying the fuel gas; and a fuel gas discharge recess that forms the communication gas flow path for discharging the fuel gas, and the fuel gas The supply recess and the fuel gas discharge recess may be formed on the same surface of the inner flat plate structure. According to this electrochemical reaction cell stack, the leak between the oxidant gas and the fuel gas can be more reliably suppressed.

(3) The electrochemical reaction cell stack may have a configuration in which at least a part of the first concave portion and the second concave portion overlap each other when viewed in the first direction. According to the present electrochemical reaction cell stack, it is possible to ensure at least one of the first recess and the second recess is longer than when the first recess and the second recess are arranged so as not to overlap each other. , Layout flexibility can be improved.

(4) In the electrochemical reaction cell stack, a welding mark is formed on the outer surface of the outer flat plate member along an imaginary line surrounding the first communication gas channel in the first direction view. It is good also as composition which has. According to this electrochemical reaction cell stack, the sealing performance of the communication gas channel can be improved, and gas leakage from the communication gas channel can be suppressed.

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

(6) The electrochemical reaction cell stack may include a gas combustion unit disposed at a position on the one side in the first direction with respect to the plurality of flat plate members. According to this 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 unit. As a result, the temperature of the reaction gas flowing into the gas flow path can be increased more efficiently, and the reaction efficiency of power generation and hydrogen generation can be improved.

  The technology disclosed in the present specification can be realized in various forms, such as an electrochemical reaction cell stack (a fuel cell stack or an electrolytic cell stack), an electrochemical reaction cell stack and a gas pipe, and the like. It is possible to implement | achieve with forms, such as an electrochemical reaction module provided with these, the manufacturing method, etc.

1 is a perspective view showing an external configuration of a fuel cell stack 100 in the present embodiment. 2 is an explanatory diagram showing an XY plane configuration on the upper side of a fuel cell stack 100 in the present embodiment. FIG. 3 is an explanatory diagram showing a YZ cross-sectional configuration of a fuel cell stack 100 at a position of III-III in FIG. 2. FIG. 4 is an explanatory diagram showing a YZ cross-sectional configuration of the fuel cell stack 100 at a position of IV-IV in FIG. 2. FIG. 5 is an explanatory diagram showing an XZ cross-sectional configuration of the fuel cell stack 100 at a position of VV in FIG. It is a perspective view which shows each external appearance structure of the inner side cover plate 300 and the lower end plate 106. FIG. It is explanatory drawing which shows the structure of the lower surface (XY plane) of the lower end plate 106. FIG. FIG. 6 is a perspective view showing an external configuration of each of a lower end plate 106 and an outer cover plate 200. It is explanatory drawing which shows the XZ cross-sectional structure of the outer side cover plate 200 and the end plate 106 in the position of IX-IX of FIG.

A. First embodiment:
A-1. Constitution:
(Configuration of fuel cell stack 100)
FIG. 1 is a perspective view showing an external configuration of a fuel cell stack 100 in the present embodiment, FIG. 2 is an explanatory diagram showing an XY plane configuration on the upper side of the fuel cell stack 100, and FIG. FIG. 4 is an explanatory diagram showing a YZ cross-sectional configuration of the fuel cell stack 100 at a position III-III, and FIG. 4 is an explanatory diagram showing a YZ cross-sectional configuration of the fuel cell stack 100 at a position IV-IV in FIG. FIG. 5 is an explanatory diagram showing an XZ cross-sectional configuration of the fuel cell stack 100 at a position VV in FIG. In each figure, XYZ axes orthogonal to each other for specifying the direction are shown. In this specification, for the sake of convenience, the positive direction of the Z axis is referred to as the upward direction, and the negative direction of the Z axis is referred to as the downward direction. However, the fuel cell stack 100 is actually different from such an orientation. It may be installed. In this specification, a direction perpendicular 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 via a support column 20 in a heat insulating container 10 in which a heat insulating material is provided on an inner surface of a casing formed of, for example, stainless steel.

  In addition, an auxiliary device 40 that is responsible for intake and exhaust of the fuel cell stack 100 is disposed below the fuel cell stack 100. Various pipes 70 extending from the outside of the heat insulating container 10 are connected to the auxiliary device 40, and oxidant gas OG, raw fuel gas, reformed water, and the like are introduced into the auxiliary device 40 through the pipe 70. At the same time, exhaust gas is discharged from the auxiliary device 40. Inside the auxiliary device 40, a reforming chamber (not shown) for reforming the raw fuel gas to generate the fuel gas FG, and a combustion chamber for burning off-gas discharged from the fuel cell stack 100 (see FIG. (Not shown) is formed. Various pipes 60 are provided between the auxiliary device 40 and the fuel cell stack 100, and the oxidizing gas OG and the fuel gas FG are supplied from the auxiliary device 40 to the fuel cell stack 100 via the pipe 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 the gas combustion section in the claims.

  As shown in FIGS. 1 to 5, the fuel cell stack 100 includes a plurality (seven in this embodiment) of fuel cell power generation units (hereinafter simply referred to as “power generation units”) 102 and a pair of end plates 104 and 106. And an outer cover plate 200 and an inner cover plate 300. 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 the present embodiment). The pair of end plates 104 and 106 are arranged so as to sandwich an assembly composed of a plurality of power generation units 102 (hereinafter referred to as “power generation block 103”) from above and below. The outer cover plate 200 is disposed below the lower end plate 106, and the inner cover plate 300 is disposed 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 power generation units 102, end plates 104, 106, and inner cover plate 300 have a plurality of (this embodiment) penetrating in the vertical direction. 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. A fastening communication hole 108 extending in the vertical direction across the end plate 106 is formed. In the following description, a hole formed in each member to constitute the fastening communication hole 108 may also be referred to as a fastening communication hole 108.

  Bolts 22 extending in the vertical direction are inserted into the fastening communication holes 108, and each power generation unit 102 and each end plate 104, 106 are integrally formed by the bolts 22 and nuts 24 fitted to both ends of the bolts 22. It is concluded. 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. The insulating sheet 26 is made of, for example, a mica sheet, a ceramic fiber sheet, a ceramic powder sheet, a glass sheet, a glass ceramic composite agent, or the like.

  As shown in FIGS. 1 to 4, a plurality of (four in this embodiment) holes penetrating in the vertical direction are formed in the peripheral portion around the Z direction of each power generation unit 102. The holes formed in the unit 102 and corresponding to each other communicate with each other in the vertical direction, thereby forming a flow passage communication hole 109 extending in the vertical direction over the assembly (the power generation block 103) configured by the plurality of power generation units 102. . In the following description, a hole formed in each power generation unit 102 to constitute the flow passage communication hole 109 may also be referred to as a flow passage communication hole 109.

  As shown in FIG. 1 to FIG. 3, the fuel cell stack 100 is located near the midpoint of one side (the side on the Y axis positive direction side of two sides parallel to the X axis) on the outer periphery around the Z direction. The communication hole 109 for the flow path functions as an oxidant gas introduction manifold 161 that 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 passage communication hole 109 functioning as the oxidant gas introduction manifold 161 has the midpoint of the one side and one side of the midpoint in the direction parallel to the side (X-axis direction) ( It arrange | positions between the nuts 24 (bolt 22) located in the X-axis negative direction. In addition, the flow passage communication hole 109 located near the midpoint of the side opposite to the side (the side on the Y-axis negative direction side 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 that is a gas flow path for discharging the oxidant off-gas OOG that is a gas discharged from the chamber 166 to the outside of the fuel cell stack 100. Specifically, the flow passage communication hole 109 functioning 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 arrange | positions between the nuts 24 (bolt 22) located in (X-axis negative direction). In the present embodiment, for example, air is used as the oxidant gas OG.

  In addition, as shown in FIGS. 1, 2, and 4, one side of the outer periphery of the fuel cell stack 100 around the Z direction (the side on the Y axis negative direction side of the two sides parallel to the X axis) The flow passage communication hole 109 located near the midpoint functions as a fuel gas introduction manifold 171 that is a gas flow passage 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 passage communication hole 109 functioning as the fuel gas introduction manifold 171 includes the midpoint of the one side and the other side of the midpoint in the direction parallel to the side (X-axis direction) (X It arrange | positions between the nuts 24 (bolt 22) located in an axial positive direction. In addition, the flow passage communication hole 109 located near the midpoint of the side opposite to the side (the side on the Y-axis positive direction side of the two sides parallel to the X-axis) is a fuel for each power generation unit 102. It functions as a fuel gas discharge manifold 172 that is a gas flow path for discharging the fuel off-gas FOG that is a gas discharged from the chamber 176 to the outside of the fuel cell stack 100. Specifically, the flow passage communication hole 109 functioning as the fuel gas discharge manifold 172 has a midpoint on the opposite side and the other side of the midpoint in the direction parallel to the side (X-axis direction) It arrange | positions between the nut 24 (bolt 22) located in a X-axis positive direction. In the present embodiment, as the fuel gas FG, for example, hydrogen-rich gas obtained by reforming city gas is used. The manifolds 161, 162, 171, and 172 have gas passages in the claims (a gas passage for supplying an oxidant gas, a gas passage for discharging an oxidant gas, and a gas passage for supplying a fuel gas). , Corresponding to a fuel gas discharge gas flow path).

(Configuration of end plates 104 and 106 and cover plates 200 and 300)
The pair of end plates 104 and 106 are substantially rectangular flat plate-shaped conductive members, and are formed of, for example, stainless steel. The upper end plate 104 is disposed on the upper side of the power generation block 103 composed of a plurality of power generation units 102, and the lower end plate 106 is disposed on the lower side of 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 formed of, for example, stainless steel. The outer cover plate 200 is disposed 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 formed of, for example, stainless steel. The inner cover plate 300 is disposed 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 positioned at one side (lower side) in the Z direction with respect to the power generation block 103 including the plurality of power generation units 102 and in the Z direction. These are a plurality of flat members arranged side by side. Outer cover plate 200 is a flat plate member located at one end (lower side) in the Z direction among the plurality of flat plate members, and corresponds to the outer flat plate member in the claims. Further, the lower end plate 106 is a flat plate member disposed between the outer cover plate 200 and the power generation block 103 among the plurality of flat plate members. It corresponds to. The configurations of the lower end plate 106 and the cover plates 200 and 300 will be described in detail later.

(Configuration 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, an air A pole-side current collector 134, a fuel-electrode-side frame 140, a fuel-electrode-side current collector 144, and a pair of interconnectors 150 that constitute the uppermost layer and the lowermost layer of the power generation unit 102 are provided. The separator 120, the air electrode side frame 130, the fuel electrode side frame 140, and the interconnector 150 are formed with holes corresponding to the fastening communication hole 108 and the flow channel communication hole 109 described above around the Z direction. Yes. Since the power generation unit 102 includes the single cell 110, the power generation block 103 described above can be expressed as a structure in which a plurality of single cells 110 are arranged in the vertical direction.

  The interconnector 150 is a substantially rectangular flat plate-shaped conductive member, and is formed of, for example, ferritic stainless steel. The interconnector 150 ensures electrical continuity between the power generation units 102 and prevents reaction gas from being mixed 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 power generation unit 102 is the same member as the lower interconnector 150 in another power generation unit 102 adjacent to the upper side of the power generation unit 102. Further, since the fuel cell stack 100 includes the pair of end plates 104 and 106, the power generation unit 102 located at the top in the fuel cell stack 100 does not include the upper interconnector 150 and is located at the bottom. The power generation unit 102 does not include the lower interconnector 150.

  The unit cell 110 includes an electrolyte layer 112, and an air electrode (cathode) 114 and a fuel electrode (anode) 116 that face each other in the vertical direction (the arrangement direction 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 electrode-supported single cell that supports the electrolyte layer 112 and the air electrode 114 with the fuel electrode 116.

  The electrolyte layer 112 is a substantially rectangular flat plate-shaped member and contains at least Zr. For example, solid oxide such as YSZ (yttria stabilized zirconia), ScSZ (scandia stabilized zirconia), CaSZ (calcia stabilized zirconia), and the like. It is formed by things. The air electrode 114 is a substantially rectangular flat plate-shaped member, and is formed of, for example, a perovskite oxide (for example, LSCF (lanthanum strontium cobalt iron oxide), LSM (lanthanum strontium manganese oxide), LNF (lanthanum nickel iron)). Has been. The fuel electrode 116 is a substantially rectangular flat plate-like member, and is formed of, for example, Ni (nickel), cermet made of Ni and ceramic particles, Ni-based alloy, or the like. Thus, 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-like member in which a substantially rectangular hole 121 penetrating in the vertical direction is formed near the center, and is made of, for example, metal. The peripheral part of the hole 121 in the separator 120 is opposed to the peripheral part of the surface of the electrolyte layer 112 on the air electrode 114 side. The separator 120 is bonded to the single cell 110 by a bonding portion formed of a brazing material (for example, Ag brazing) disposed in the facing portion. The separator 120 divides the air chamber 166 facing the air electrode 114 and the fuel chamber 176 facing the fuel electrode 116, and gas leaks from one electrode side to the other electrode side in the peripheral portion of the single cell 110. It is suppressed.

 The air electrode side frame 130 is a frame-like member in which a substantially rectangular hole 131 penetrating in the vertical direction is formed near the center, and is formed of an insulator such as mica, for example. The hole 131 of the air electrode side frame 130 forms an air chamber 166 that faces the air electrode 114. The air electrode side frame 130 is in contact with the peripheral portion of the surface of the separator 120 opposite to the side facing the single cell 110 and the peripheral portion of the surface of the interconnector 150 facing the air electrode 114. . The air electrode side frame 130 electrically insulates 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. A communicating oxidant gas discharge communication hole 133 is formed.

  The fuel electrode side frame 140 is a frame-like member in which a substantially rectangular hole 141 penetrating in the vertical direction is formed near the center, and is made of, for example, metal. The hole 141 of the fuel electrode side frame 140 forms a fuel chamber 176 that faces the fuel electrode 116. The fuel electrode side frame 140 is in contact with the peripheral portion of the surface of the separator 120 facing the single cell 110 and the peripheral portion of the surface of the interconnector 150 facing the fuel electrode 116. As shown in FIG. 3, the fuel electrode side frame 140 has a fuel gas supply communication hole 142 that communicates the fuel gas introduction manifold 171 and the fuel chamber 176, and a 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 disposed 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 electrode side current collector 144 is in contact with the surface of the fuel electrode 116 opposite to the side facing the electrolyte layer 112 and the surface of the interconnector 150 facing the fuel electrode 116. However, as described above, the lowermost power generation unit 102 in the fuel cell stack 100 does not include the lower interconnector 150, so the fuel electrode side current collector 144 in the power generation unit 102 has the lower power connector 144. It is in contact with the end plate 106. Since the fuel electrode side current collector 144 has such a configuration, the fuel electrode 116 and the interconnector 150 (or the end plate 106) are electrically connected. 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 electrode side current collector 134 is disposed 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 facing the air electrode 114. However, as described above, since the power generation unit 102 located at the top in the fuel cell stack 100 does not include the upper interconnector 150, the air electrode side current collector 134 in the power generation unit 102 includes the upper end plate. 104 is in contact. 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.

(Configuration of lower end plate 106 and cover plates 200 and 300)
6 is a perspective view showing the external configuration of each of the inner cover plate 300 and the lower end plate 106, and FIG. 7 is an explanatory diagram showing the configuration of the lower surface (XY plane) of the lower end plate 106. FIG. 8 is a perspective view showing the external configuration of each of the lower end plate 106 and the outer cover plate 200. In FIG. 7, the position of the outer cover plate 200 is indicated by a broken line so as to overlap the configuration of the lower end plate 106.

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

  As shown in FIGS. 2, 3, and 5 to 7, one of the inner flow passage recesses 107 </ b> U, the shape of the inner flow passage recess 107 </ b> U is a predetermined direction (Y direction). It is the linear shape extended along. One end portion (the end portion in the Y-axis positive direction) of the one inner channel recess 107U is disposed at a position overlapping the oxidant gas introduction manifold 161 when viewed in the Z direction, and communicates with the oxidant gas introduction manifold 161. doing. A through-hole 105 for a flow path penetrating the lower end plate 106 in the vertical direction is formed at the other end portion (the end portion in the negative Y-axis direction) of the one inner flow path recess portion 107U.

  Of the two inner flow path recesses 107U, the other inner flow path recess 107U has a bent line shape extending in a direction intersecting with the longitudinal direction of one inner flow path recess 107U while being bent. It is the shape. One end portion (end portion in the negative Y-axis direction) of the other inner channel recess 107U is disposed at a position overlapping the oxidant gas discharge manifold 162 as viewed in the Z direction, and communicates with the oxidant gas discharge manifold 162. doing. At the other end (the end in the Y-axis positive direction) of the other inner channel recess 107U, a channel through-hole 105 that penetrates the lower end plate 106 in the vertical direction is formed. In addition, as viewed in the Z direction, the direction in which the two flow passage through holes 105 formed in each of the two inner flow passage recesses 107U are arranged is that the oxidant gas introduction manifold 161 and the oxidant gas discharge manifold 162 are arranged. It is substantially orthogonal to the direction.

  Furthermore, a rib 178U extending along the longitudinal direction is formed in each inner channel recess 107U. Specifically, the shape of the rib 178U formed in the one inner flow passage recess 107U as viewed in the Z direction passes through a substantially central position in the short direction of the one inner flow passage recess 107U, and It is the shape extended linearly along the longitudinal direction of this one inside flow path recessed part 107U. The shape of the rib 178U formed in the other inner flow path recess 107U as viewed in the Z direction passes through a substantially central position in the short side direction of the other inner flow path recess 107U, and the other inner flow path It is a polygonal line shape that is bent so as to correspond to the shape of the road recess 107U and extends along the longitudinal direction of the other inner flow path recess 107U. The height dimension in the Z-axis direction of each rib 178U may be substantially the same as the depth dimension in the Z-axis direction of each inner channel recess 107U, or the depth in the Z-axis direction of each inner channel recess 107U. It may be smaller than the size.

  As shown in FIG. 6, the outer peripheral shape of the inner cover plate 300 as viewed in the Z direction is a substantially rectangular shape, similar to the outer peripheral shape of the lower end plate 106. 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 channel 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 passage recesses 107 </ b> U overlap with the corresponding inner flow passage recesses 107 </ b> U as viewed in the Z direction, and It is arranged at a position overlapping the manifolds 161 and 162. In a state where the inner cover plate 300 is disposed on the upper surface of the lower end plate 106, a portion that does not overlap the relay hole 302 in each inner flow path recess 107 </ b> U is blocked by the inner cover plate 300. Therefore, a space constituted by each inner flow passage recess 107U is secured inside the structure constituted by the inner cover plate 300 and the lower end plate 106. The two relay holes 302 corresponding to the two outer channel recesses 107D are disposed at positions overlapping the corresponding outer channel recesses 107D and the manifolds 171 and 172 as viewed in the Z direction. For this reason, each relay hole 302 communicates with each manifold 171, 172. A fastening communication hole 108 is formed between the pair of relay holes 302 arranged in the X-axis direction.

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

  As shown in FIGS. 2, 4, 5, 7, and 8, one of the two outer channel recesses 107 </ b> D has one of the outer channel recesses 107 </ b> D having a predetermined direction ( It is a linear shape extending along the (Y direction). One end portion (end portion in the negative Y-axis direction) of the one outer channel recess 107D is disposed at a position overlapping the fuel gas introduction manifold 171 when viewed in the Z direction, A passage through-hole 105 that penetrates the end plate 106 in the vertical direction is formed. For this reason, the flow passage through hole 105 formed in the one outer flow passage recess 107 </ b> D communicates with the fuel gas introduction manifold 171 through the relay hole 302 formed in the inner cover plate 300. The other end portion (the end portion in the Y-axis positive direction) of the one inner channel recess 107U overlaps one of four gas holes 202 described later formed in the outer cover plate 200 in the Z direction view. Is arranged.

  Of the two outer channel recesses 107D, the other outer channel recess 107D has a bent line shape extending in a direction intersecting with the longitudinal direction of one outer channel recess 107D while being bent. It is the shape. One end portion (the end portion in the Y-axis positive direction) of the other outer flow path recess portion 107D is disposed at a position overlapping the fuel gas discharge manifold 172 as viewed in the Z direction. A passage through-hole 105 that penetrates the end plate 106 in the vertical direction is formed. For this reason, the flow path through hole 105 formed in the other outer flow path recess 107 </ b> D communicates with the fuel gas discharge manifold 172 via the relay hole 302 formed in the inner cover plate 300. The other end (the Y-axis negative direction end) of the other outer channel recess 107D is disposed at a position that overlaps one of four gas holes 202 (described later) formed in the outer cover plate 200 as viewed in the Z direction. Has been. As viewed in the Z direction, the direction in which the two flow passage through holes 105 formed in each of the two outer flow passage 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, in view of the layout, when viewed through the lower end plate 106 in the Z direction, the other inner flow passage recess 107 </ b> U and the other outer flow The road recesses 107D partially overlap each other and are partitioned in the vertical direction by the lower end plate 106.

  As shown in FIGS. 7 and 8, the outer peripheral shape of the outer cover plate 200 as viewed in the Z direction overlaps the outer peripheral shape of the lower end plate 106 with the fastening communication hole 108, that is, four corner portions. And it is the shape by which the notch (outer shape recessed part Pa) was formed in the position of the approximate center part of each edge | side. The outer cover plate 200 is formed with four gas holes 202 penetrating 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 in the claims (oxidant gas supply gas holes, oxidant gas discharge gas holes, fuel gas supply gas holes, fuel gas discharge gas holes). ).

  As shown in FIGS. 2, 3, and 7, the two gas holes 202 corresponding to the two inner flow passage recesses 107 </ b> U are positions where they do not overlap with the manifolds 161 and 162, specifically, as viewed in the Z direction. , And is disposed at a position overlapping the flow passage through hole 105 formed in the corresponding inner flow passage recess 107U. For this reason, the two gas holes 202 formed in the outer cover plate 200 communicate with the space formed by the inner flow path recesses 107 </ b> U via the flow path through holes 105.

  The two gas holes 202 corresponding to the two outer flow path recesses 107D are positioned so as not to overlap the manifolds 171 and 172 in the Z direction, specifically, at both ends of the corresponding outer flow path recesses 107D. Inside, the flow path through-hole 105 is disposed at a position overlapping with the end portion where it is not formed. In a state where the outer cover plate 200 is disposed on the lower surface of the lower end plate 106, a portion that does not overlap with the gas hole 202 in each outer flow path recess 107 </ b> D is blocked by the outer cover plate 200. Therefore, a space formed by each outer flow path recess 107 </ b> D is secured inside the structure formed by the outer cover plate 200 and the lower end plate 106. The space constituted by the flow path recesses 107U and 107D opens to the outside of the fuel cell stack 100 through the gas holes 202, and the corresponding manifolds 161, 162, through the flow path through holes 105. 171 and 172 communicate with each other. That is, a communication gas flow path that connects the gas hole 202 and the manifolds 161, 162, 171, and 172 is formed by the space formed by the flow path recesses 107. Hereinafter, the communication gas flow path communicating with the oxidant gas introduction manifold 161 is referred to as the oxidant gas introduction communication flow path 163, and the communication gas flow path communicating with the oxidant gas discharge manifold 162 is referred to as the oxidant gas discharge communication flow path. The communication gas flow path that communicates with the fuel gas introduction manifold 171 is called a fuel gas introduction communication flow path 173, and the communication gas flow path that communicates with the fuel gas discharge manifold 172 is called a fuel gas discharge communication flow path 174. . The fuel gas introduction communication channel 173 and the fuel gas discharge communication channel 174 are the first communication gas channel in the claims (the communication gas channel for supplying fuel gas, the communication gas flow for discharging fuel gas). 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 (the communication gas flow path for supplying the oxidant gas, the oxidation gas). This corresponds to a communication gas flow path for discharging the 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 channel 163, and the oxidant gas discharge communication channel 164 includes 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 the fuel gas FG from the auxiliary device 40 is connected to the fuel gas introduction communication flow path 173, and the fuel gas discharge communication flow path 174 has a fuel flow 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 joined to the lower end plate 106 by welding. More specifically, on the lower surface of the outer cover plate 200, an outer circumferential weld mark 220 that joins the outer cover plate 200 and the lower end plate 106 along the vicinity of the outer circumferential line OL of the outer cover plate 200 as viewed in the Z direction. Is formed. Further, on the lower surface of the outer cover plate 200, the flow path welding trace that joins the outer cover plate 200 and the lower end plate 106 along the virtual line VL surrounding each flow path recess 107 as viewed in the Z direction. 210 is formed. As a result, the communication gas flow paths (oxidant gas introduction communication flow path 163, oxidant gas discharge communication flow path 164, fuel gas introduction communication flow path 173, fuel gas discharge communication flow formed by the recesses 107 for each flow path are formed. The sealing performance of the path 174) is enhanced. The flow path welding mark 210 corresponds to the welding mark in the claims.

  As shown in FIG. 9 showing the XZ cross-sectional configuration at the position 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 welding mark 220 and the flow path welding mark 210 are formed in the welding recess 230. Further, the outer circumference 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 be joined to the lower end plate 106 by welding similarly to the outer cover plate 200.

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

  When the oxidant gas OG is supplied to the air chamber 166 of each power generation unit 102 and the fuel gas FG is supplied to the fuel chamber 176, oxygen contained in the oxidant gas OG and hydrogen contained in the fuel gas FG in the single cell 110. Power is generated by an electrochemical reaction. This power generation reaction is an exothermic reaction. In each power generation unit 102, the air electrode 114 of the single cell 110 is electrically connected to one interconnector 150 (or the upper end plate 104) via an air electrode side current collector 134, and the fuel electrode 116 is a fuel electrode. It is electrically connected to the other interconnector 150 (or the lower end plate 106) via the side current collector 144. The plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. Therefore, electrical energy generated in each power generation unit 102 is taken out from the end plates 104 and 106 that function as output terminals of the fuel cell stack 100. Since SOFC generates power at a relatively high temperature (for example, 700 ° C. to 1000 ° C.), the fuel cell stack 100 is heated by a heater (after the startup until the high temperature can be maintained by heat generated by power generation) (Not shown).

  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. The oxidant gas discharge communication channel 164 is discharged, and the oxidant gas discharge communication channel 164 is discharged to the auxiliary device 40 via the pipe 60 outside 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 via the fuel gas discharge communication hole 143 of each power generation unit 102 is discharged from the fuel gas discharge manifold 172. It is discharged to the communication channel 174 and discharged from the fuel gas discharge communication channel 174 to the auxiliary device 40 via the pipe 60 outside 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 discharged to the outside of the heat insulating container 10 through the pipe 70.

A-3. Effects of this embodiment:
As described above, the fuel cell stack 100 of this embodiment includes the power generation block 103 in which a plurality of single cells 110 (power generation units 102) are arranged in the vertical direction, and one side in the vertical direction with respect to the power generation block 103 ( A plurality of flat plate-shaped end plates 106 and cover plates 200 and 300 are arranged in the vertical direction at the lower side. Further, the fuel cell stack 100 is formed with manifolds 161, 162, 171, and 172 that are gas passages extending over the power generation block 103. Of the plurality of flat plate members, the end plate 106 and the cover plates 200, 300, an outer cover plate 200 (outer flat plate shape) that is a flat plate member positioned on the one side (lower side) end in the vertical direction. A gas hole 202 is formed on the one side (lower side) surface (outer surface) of the member) at a position that does not overlap the manifolds 161, 162, 171, and 172 as viewed in the Z direction. Further, the gas hole 202 provided on the lower surface of the outer cover plate 200 and the manifolds 161, 162, 171 are provided in the structure constituted by the plurality of flat plate members (the end plate 106 and the cover plates 200, 300). , 172 to communicate with each other (oxidant gas introduction communication channel 163, oxidant gas discharge communication channel 164, fuel gas introduction communication channel 173, fuel gas discharge communication channel 174). Yes. 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 from the gas holes 202 provided on the lower surface of the outer cover plate 200. It flows into each communication gas flow path (oxidant gas introduction communication flow path 163 and fuel gas introduction communication flow path 173) formed inside the structure constituted by the end plate 106 and the cover plates 200 and 300, and thereafter It flows into each manifold (oxidant 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 communication gas flow paths 163 and 173, heat from the single cell 110 is obtained. As a result, the temperatures of the oxidant gas OG and the fuel gas FG rise. Therefore, according to the fuel cell stack 100 of the present embodiment, each manifold 161, compared to the configuration in which the oxidant gas OG and the fuel gas FG flow into the manifolds 161, 171 directly 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 increased, and the temperature of the single cell 110 is lowered by the oxidant gas OG and the fuel gas FG that are directly supplied from the outside and are relatively low in temperature. This 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, each communication gas flow path 163, 164, 173, 174 is formed inside the structure constituted by the end plate 106 and the cover plates 200, 300. The length of the piping 60 outside 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 a reduction in size and a simplification of a module including the fuel cell stack 100 and a gas pipe outside the fuel cell stack 100. Further, since the length of the pipe 60 outside the fuel cell stack 100 is short, the temperature of the oxidant off-gas OOG and the fuel off-gas FOG discharged from the fuel cell stack 100 is suppressed from decreasing, and thus the oxidant off-gas OOG. In addition, 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 constituted by a flat plate member excluding the outer cover plate 200 which is an outer flat plate member among the end plate 106 and the outer cover plate 200 which are the plurality of flat plate members. On the one side (lower side) of the inner flat plate structure (that is, the end plate 106), the channel recesses 107 constituting the communication gas channels 163, 164, 173, and 174 are formed, and the outer cover plate is formed. The 200 gas holes 202 are disposed at positions corresponding to the corresponding channel recesses 107 when viewed in the Z direction, and portions of the channel recesses 107 not overlapping the gas holes 202 are blocked by the outer cover plate 200. ing. Therefore, according to the fuel cell stack 100 of the present embodiment, each communication gas flow path is provided inside the structure constituted by the outer cover plate 200 and the end plate 106 while suppressing an 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 (the fuel gas introduction communication flow path 173 and the 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 the one side of the inner flat plate structure (lower end plate 106). The second communication gas channel (oxidant gas introduction communication channel 163 and oxidant gas introduction communication channel 163 and the first communication gas channel is formed independently of the first communication gas channel and used for supplying the oxidant gas OG and discharging the oxidant off-gas OOG). The inner channel recess 107U constituting the oxidant gas discharge communication channel 164) is formed on the surface (upper surface) on the other side of the inner plate structure. For this reason, compared with the case where the concave portion for the flow path constituting the first communication gas flow path and the concave portion for the flow path constituting the second communication gas flow path are formed on the same surface of the inner flat plate structure. Thus, gas leakage between the first communication gas channel and the second communication gas channel can be suppressed.

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

  Further, in the fuel cell stack 100 of the present embodiment, flow path welding marks 210 are formed on the lower surface of the outer cover plate 200 along virtual lines VL that surround the communication gas flow paths 173 and 174 when viewed in the Z direction. Yes. Therefore, according to the fuel cell stack 100 of the present embodiment, the sealing performance of the communication gas flow paths 173 and 174 can be improved, and gas leakage from the communication 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 circumferential weld trace 220 is also formed in the welding recess 230, it is possible to suppress the outer circumferential weld trace 220 from protruding from the lower surface of the outer cover plate 200. it can.

  Each channel recess 107 is formed with ribs 178U and 178D extending along the longitudinal direction of the channel recess 107. As a result, the portion of the end plate 106 that is thinned by the formation of the channel recess 107 is reinforced, so that the gas in each communication gas channel is suppressed while suppressing deformation of the portion. Pressure loss can be suppressed.

  The oxidant gas introduction communication channel 163, the oxidant gas discharge communication channel 164, the fuel gas introduction communication channel 173, and the fuel gas discharge communication channel 174 are disposed between the power generation block 103 and the auxiliary device 40. ing. Thereby, the gas which flows through each communicating gas channel 163,164,173,174 by the heat from auxiliary device 40 can be heated more effectively.

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

  The configuration of the fuel cell stack 100 in the above embodiment is merely an example, and various modifications can be made. For example, in the above embodiment, the communication gas flow paths 163, 164, 173, and 174 are formed by forming the flow path recesses 107 in the end plate 106, but instead of the end plate 106, or Further, in addition to the end plate 106, a flat channel member other than the end plate 106 (for example, a terminal plate disposed between the power generation block 103 and the end plate 106) is provided with a similar recess for flow path so that each communication is established. Gas flow paths 163, 164, 173, 174 may be formed.

  In the above-described embodiment, the communication gas flow paths 163, 164, 173, and 174 are formed inside the structure constituted by the three plate-like members of the end plate 106 and the cover plates 200 and 300. However, the communication gas flow paths 163, 164, 173, and 174 may be formed inside a structure constituted by two or four or more flat plate-like members. For example, in the above-described embodiment, the end plate 106 is constituted by a plurality of flat plate members, and each communication gas is formed inside the structure constituted by the plurality of flat plate members constituting the end plate 106 and the cover plates 200 and 300. The flow paths 163, 164, 173, and 174 may be formed. In this case, a through hole in the vertical direction is formed in one or a plurality of flat plate 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 holes may function as the respective communication gas flow paths 163, 164, 173, and 174 by being blocked by other flat plate members.

  Further, in the above-described embodiment, the outer flow path recess 107D is formed on the surface on one side in the first direction, and the surface on the other side in the first direction in one flat plate member (end plate 106). The inner flow path recess 107U is formed in the inner flat plate structure constituted by a plurality of flat plate members, and the outer flow path recess 107D is formed on the one surface. An inner channel recess 107U may be formed on the surface of the inner channel. Further, for example, in the above-described embodiment, when the inner flat plate structure is constituted by a plurality of flat plate members, two outer flow path recesses 107D are formed on the surface of the one side of the different flat plate members. Two concave portions 107U for the inner flow path may be formed on the surface of the other side of the flat plate members different from each other.

  In the above-described embodiment, four flow path recesses 107 corresponding to each of the four gas flow paths (manifolds 161, 162, 171, 172) are formed on 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 in the first direction of the inner flat plate structure, and the other side in the first direction. It is only necessary that the channel recess 107 corresponding to at least one other gas channel is formed on the surface. For example, in the above embodiment, one of the four gas holes 202 is disposed at a position overlapping the oxidant gas discharge manifold 162 in the Z direction view, and the oxidant gas discharge manifold 162 is disposed on the end plate 106. The inner flow passage recess 107U corresponding to may not be formed. The other one of the four gas holes 202 is disposed at a position overlapping the fuel gas discharge manifold 172 as viewed 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 increased, and the reaction efficiency of power generation in each single cell 110 can be improved. The power generation performance of the fuel cell stack 100 can be improved. In addition, an outer flow path recess 107D corresponding to the oxidant gas introduction manifold 161 is formed on the one surface of the inner flat plate structure, and the oxidant gas discharge manifold 162 is formed on the other surface. An inner flow path recess 107U may be formed. Thereby, the leak 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, the length of the other inner flow path recess 107U and the length of the other outer flow path recess 107D are the same, but they may be different from each other. For example, the outer channel recess 107D to which the fuel gas FG is supplied is made longer than the inner channel recess 107U to which the oxidant gas OG is supplied so that the fuel gas FG is warmed more. Good.

  In the above embodiment, the inner channel recess 107U and the outer channel recess 107D partially overlap each other as viewed in the Z direction. However, the inner channel recess 107U and the outer channel recess 107D are different from each other. , They may not overlap each other when viewed in the Z direction. However, as described in, for example, International Publication No. 2016/63157, a fuel cell including a heat exchanging portion in which a heat exchanging channel for flowing an oxidant gas for heat exchange is formed between power generation units. In the stack, a plurality of gas flow paths become complicated. For this reason, it becomes difficult to form the recessed part for flow paths in an inner side plate structure so that the communication gas flow path connected to each gas flow path does not communicate. In such a case, the present invention is applied, and further, the channel recess formed on one surface of the inner flat plate structure and the channel recess formed on the other surface overlap in the Z direction view. By arrange | positioning in this way, the freedom degree of arrangement | positioning layout of the recessed part for flow paths in an inner side flat plate structure can be improved.

  In the above embodiment, the inner cover plate 300 is disposed between the power generation block 103 and the end plate 106. However, the inner cover plate 300 is not provided, and the power generation block 103 and the end plate 106 are disposed adjacent to each other. It may be. In this case, for example, the interconnector 150 positioned at the one end of the power generation block 103 may serve 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 disposed on the upper surface of the upper end plate 104, and a communication gas flow path may be formed inside a structure constituted by the upper end plate 104 and the cover plate. Further, it is not necessary to form all the communication gas flow paths 163, 164, 173, and 174 in the fuel cell stack 100, and it is sufficient that at least one communication gas flow path is formed.

  In the above embodiment, the flow passage 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 used for the flow passage. It may also function as the communication hole 109.

  Moreover, in the said embodiment, although the welding mark 210 for flow paths and the outer periphery welding mark 220 are all formed in the recessed part 230 for welding, only a part of the welding marks 210 for flow paths and the outer periphery welding marks 220 are shown. It may be formed in the recess 230 for welding.

  Moreover, in the said embodiment, at least one of the flow path welding trace 210 and the outer periphery welding trace 220 does not need to be formed. In the above embodiment, the welding recess 230 may not be formed in the outer cover plate 200.

  Moreover, in the said embodiment, the shapes, such as the outer side cover plate 200 demonstrated using the virtual line VL, are not essential and can be variously deformed.

  In the above-described embodiment, the shape of the ribs 178U and 178D viewed in the Z direction may be a shape that does not follow the longitudinal direction of the corresponding flow path recess 107. Further, at least one of the four flow path recesses 107 may not have a rib.

  In the above embodiment, the number of power generation units 102 (single cells 110) included in the fuel cell stack 100 is merely an example, and the number of power generation units 102 (single cells 110) is required for the fuel cell stack 100. It is determined appropriately according to the output voltage and the like. In the above-described embodiment, a conductive layer that does not have a power generation function between one power generation unit 102 and another power generation unit 102 (for example, a layer for securing a gas flow path in the plane direction). May be interposed. Even in this case, the structure in the range from the uppermost power generation unit 102 to the lowermost power generation unit 102 (that is, including a conductive layer that does not have the power generation function) is the power generation block 103. .

  Moreover, the material which forms each member in the said embodiment is an illustration to the last, and each member may be formed with another material. For example, the cover plates 200 and 300 and the end plate 106 may be formed of the same material.

  In the present specification, the fact that the member B and the member C are opposed to each other across the member (or a part having the member, the same applies hereinafter) A is not limited to the form in which the member A and the member B or C are adjacent to each other, It includes a form in which another component is interposed between member A and member B or 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.

  In the above embodiment, the SOFC that generates electricity using the electrochemical reaction between hydrogen contained in the fuel gas and oxygen contained in the oxidant gas is targeted. The present invention can be similarly applied to an electrolytic single cell that is a constituent unit of a solid oxide electrolytic cell (SOEC) that generates hydrogen by using hydrogen, and an electrolytic cell stack including a plurality of electrolytic single cells. The configuration of the electrolysis cell stack is well known as described in, for example, Japanese Patent Application Laid-Open No. 2006-81813, and therefore will not be described in detail here, but is roughly the same as the fuel cell stack 100 in the above-described embodiment. It is the composition. That is, the fuel cell stack 100 in the above-described embodiment may be read as an electrolytic cell stack, the power generation unit 102 may be read as an electrolytic cell unit, and the single cell 110 may be read as an electrolytic single cell. However, when the electrolytic cell stack is operated, 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 passage communication hole 109 is used. Water vapor as a source gas is supplied through As a result, an electrolysis reaction of water occurs in each electrolysis cell unit, hydrogen gas is generated in the fuel chamber 176, and hydrogen is taken out of the electrolysis cell stack through the flow passage communication hole 109. Even in an electrolytic cell stack having such a configuration, the same operation and effect as in the above embodiment can be achieved if the configuration is similar to that in the above embodiment.

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

DESCRIPTION OF SYMBOLS 10: Thermal insulation container 20: Strut 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 paths Through hole 107: Channel recess 107D: Outer channel recess 107U: Inner channel recess 108: Fastening communication hole 109: Channel communication hole 110: Single cell 112: Electrolyte layer 114: Air electrode 116: Fuel Electrode 120: Separator 121: Hole 130: Air electrode side frame 131: Hole 132: Oxidant gas supply communication hole 133: Oxidant gas discharge communication hole 134: Air electrode side current collector 140: Fuel electrode side frame 141: Hole 142 : Fuel gas supply communication hole 143: Fuel gas discharge communication hole 144: Fuel electrode side current collector 150: Connector 161: Oxidant gas introduction manifold 162: Oxidant gas discharge manifold 163: Oxidant gas introduction communication channel 164: Oxidant gas discharge communication channel 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 trace for flow path 220: Outer welding mark 230: For welding Recess 300: Inner cover plate 302: Relay hole FG: Fuel gas FOG: Fuel off-gas OG: Oxidant gas OL: Peripheral line OOG: Oxidant off-gas Pa: External recess VL: Virtual line

Claims (6)

An electrochemical reaction block in which a plurality of electrochemical reaction single cells each including an electrolyte layer and an air electrode and a fuel electrode facing each other in a first direction across the electrolyte layer are arranged in the first direction;
A plurality of plate-like 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 across the electrochemical reaction block are formed,
The outer surface, which is the surface of the one side of the outer flat plate member, which is the flat plate member located at the end of the one side in the first direction among the plurality of flat plate members, A plurality of gas holes are formed at positions that do not overlap with the gas flow path in a direction view,
A plurality of communication gas flow paths that connect the gas holes and the gas flow paths are formed inside the structure constituted by the plurality of flat plate members,
Of the plurality of plate-like members, the first plate in the inner plate structure constituted by one or a plurality of the plate-like members disposed between the outer plate-like member and the electrochemical reaction block. On the surface of the one side, a first recess that forms a first communication gas channel among the plurality of communication gas channels is formed,
A second recess that constitutes a second communication gas channel of the plurality of communication gas channels is formed on the surface of the other side in the first direction of the inner flat plate structure. Characteristic electrochemical reaction cell stack. The electrochemical reaction cell stack according to claim 1,
The plurality of gas flow paths include a gas flow path for supplying an oxidant gas, a gas flow path for discharging an 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 an oxidant gas, a gas hole for supplying a fuel gas, and a gas hole for discharging a fuel gas,
One of the first communication gas flow channel and the second communication gas flow channel includes a gas hole for supplying the oxidant gas and a gas flow channel for supplying the oxidant gas. A communicating gas flow path for supplying oxidant gas that communicates, and a communicating gas flow path for discharging oxidant gas that communicates the gas hole for discharging oxidant gas and the gas flow path for discharging oxidant gas. Including
The other communication gas flow channel among the first communication gas flow channel and the second communication gas flow channel communicates the fuel gas supply gas hole and the fuel gas supply gas flow channel. A communication gas flow path for fuel gas supply, a communication gas flow path for fuel gas discharge that communicates the gas hole for fuel gas discharge and the gas flow path for fuel gas discharge,
Of the first recess and the second recess, the recess constituting the one communication gas flow path includes an oxidant gas supply recess forming the oxidant gas supply communication path, and A recess for discharging the oxidant gas constituting the communication 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 arranged on the inner side. It is formed on the same surface in the flat plate structure,
Of the first recess and the second recess, the recess that constitutes the other communication gas flow path includes a fuel gas supply recess that constitutes the fuel gas supply communication gas, and the fuel. A fuel gas discharge recess that constitutes a communication gas flow path for gas discharge, and the fuel gas supply recess and the fuel gas discharge recess are the same in the inner plate structure. An electrochemical reaction cell stack, characterized by being formed on a surface. The electrochemical reaction cell stack according to claim 1 or 2,
The electrochemical reaction cell stack, wherein at least a part of the first concave portion and the second concave portion overlap each other when viewed in the first direction. In the electrochemical reaction cell stack according to any one of claims 1 to 3,
The outer surface of the outer flat plate member is formed with welding marks along an imaginary line surrounding the first communication gas flow path when viewed in the first direction. Cell stack. In the electrochemical reaction cell stack according to any one of claims 1 to 4,
The electrochemical reaction cell stack, wherein a rib extending along a longitudinal direction of the concave portion is formed in at least one of the first concave portion and the second concave portion. In the electrochemical reaction cell stack according to any one of claims 1 to 5,
An electrochemical reaction cell stack comprising a gas combustion section disposed at a position on the one side in the first direction with respect to the plurality of plate-like members.

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