JP6667214B2 - Fuel cell structure - Google Patents

Description

  The technology disclosed in the present specification relates to a fuel cell structure.

  A solid oxide fuel cell (hereinafter, also referred to as "SOFC") is generally used in the form of a fuel cell stack including a plurality of power generation units arranged in a predetermined direction (hereinafter, also referred to as "arrangement direction"). Is done. The power generation unit is the minimum unit of power generation, and includes an electrolyte layer and an air electrode and a fuel electrode that face each other in the arrangement direction with the electrolyte layer interposed therebetween.

  In general, a fuel cell stack has a plurality of bolt holes extending in the arrangement direction over a plurality of power generation units, and is fastened by bolts inserted into each of the plurality of bolt holes and a nut fitted to each bolt. (For example, see Patent Document 1).

JP 2014-212090 A

  In the above-described conventional configuration, the seating surface of the nut comes into contact with the surface of a member (for example, an end plate) constituting the fuel cell stack, and the fastening stress is concentrated on the contacting portion. This may reduce the fastening force and cause gas leakage and poor contact.

  Such a problem is not limited to bolts and nuts, but is a problem common to fuel cell stacks fastened by fastening members. Further, such a problem is not limited to the fuel cell stack, but is a problem common to a structure including a plurality of power generation units (this structure is referred to as a “fuel cell structure” in this specification). Further, such a problem is not limited to the SOFC, and is a problem common to other types of fuel cell structures.

  This specification discloses a technique capable of solving at least a part of the above-described problem.

  The technology disclosed in this specification can be realized, for example, as the following modes.

(1) The fuel cell structure disclosed in the present specification includes a plurality of power generation units arranged in a first direction, a shaft portion extending in the first direction and having a threaded portion, A plurality of fastening members each including a flange portion located on one side in the first direction with respect to a shaft portion, wherein the fuel cell structure fastened by the plurality of fastening members further comprises: It is arranged on the one side in the first direction with respect to a plurality of power generation units, and directly on a seating surface which is a surface on the other side in the first direction in the flange portion of the plurality of fastening members, or A first member that is in contact with the first member through the member, and the screw portion that is disposed on the other side in the first direction with respect to the plurality of power generation units and that is formed on the shaft portion of the plurality of fastening members. A second member formed with a plurality of screw holes to be screwed together; Characterized in that it obtain. According to the present fuel cell structure, the seating surface of the flange portion of each fastening member is in contact with the first member directly or via another member, and a plurality of screw holes are formed in the second member. Since the screw portion formed on the shaft portion of each fastening member is screwed into each screw hole of the second member, the fastening force is directly generated in the second member, and the second member Concentration of the fastening stress on a part of the second member can be prevented, local deformation of the second member can be suppressed, and occurrence of gas leakage and contact failure can be suppressed.

(2) In the fuel cell structure, the shaft portion and the flange portion of the fastening member may be configured as an integral member. According to the present fuel cell structure, for example, the shaft portion and the flange portion are separate from each other, and the number of screwed portions is reduced as compared with a configuration in which the shaft portion and the flange portion are screwed. The management can be facilitated, and the loosening of the threaded portion during long-term use can be suppressed.

(3) In the fuel cell structure, the position of the end of the screw portion on the other side in the first direction in the first direction is the end of the screw hole on the other side in the first direction. May be the same as the position in the first direction, or may be the other side in the first direction. According to the fuel cell structure of the present invention, the position of the end of the screw portion is on the one side in the first direction from the position of the end of the screw hole. Since the number of bites can be made constant and increased, the fastening force can be stabilized, and the durability of the threaded portion can be improved.

(4) In the above fuel cell structure, the fuel cell structure includes the plurality of power generation units, and the first member and the second member that form an end in the first direction. The battery stack may be configured such that the first member and the second member are flat members. According to the present fuel cell structure, it is possible to suppress the occurrence of gas leakage and poor contact in the fuel cell stack.

(5) In the fuel cell structure, the fuel cell structure includes a fuel cell stack including the plurality of power generation units, a combustion chamber for burning gas discharged from the fuel cell stack, and a raw fuel gas. And a reforming chamber for producing a fuel gas to be supplied to the fuel cell stack. The auxiliary unit is formed with at least one of the reforming chamber, and the second member is the auxiliary unit. It may be configured. According to the present fuel cell structure, it is possible to suppress the occurrence of gas leakage and poor contact in the power generation module including the fuel cell stack and the auxiliary device.

  The technology disclosed in the present specification can be realized in various forms, for example, a fuel cell structure, a fuel cell stack, a power generation module including a fuel cell stack and an auxiliary device, a power generation module. It can be realized in the form of a fuel cell system or the like provided.

FIG. 1 is a perspective view illustrating an external configuration of a fuel cell stack 100 according to a first embodiment. FIG. 2 is an explanatory diagram illustrating an XY plane configuration on an upper side of the fuel cell stack 100 according to the first embodiment. FIG. 3 is an explanatory diagram illustrating an XY plane configuration of a lower side of the fuel cell stack 100 according to the first embodiment. FIG. 4 is an explanatory diagram illustrating an XZ cross-sectional configuration of the fuel cell stack 100 at a position IV-IV in FIGS. 1 to 3. FIG. 5 is an explanatory diagram showing a YZ sectional configuration of the fuel cell stack 100 at a position VV in FIGS. 1 to 3. FIG. 5 is an explanatory diagram illustrating an XZ cross-sectional configuration of two power generation units 102 adjacent to each other at the same position as the cross-section illustrated in FIG. 4. FIG. 6 is an explanatory diagram illustrating a YZ cross-sectional configuration of two power generation units 102 adjacent to each other at the same position as the cross-section illustrated in FIG. 5. FIG. 7 is an explanatory diagram illustrating an XY cross-sectional configuration of a power generation unit 102 at a position VIII-VIII in FIG. 6. FIG. 7 is an explanatory diagram illustrating an XY cross-sectional configuration of a power generation unit 102 at a position of IX-IX in FIG. 6. FIG. 2 is an explanatory diagram showing an XZ cross-sectional configuration for fastening a fuel cell stack 100. FIG. 9 is an explanatory diagram showing an XZ cross-sectional configuration for fastening a fuel cell stack 100 ′ of a comparative example. FIG. 9 is an explanatory diagram showing an XZ cross-sectional configuration for fastening a fuel cell stack 100a according to a first modification of the first embodiment. FIG. 9 is an explanatory diagram showing an XZ cross-sectional configuration for fastening a fuel cell stack 100b according to a second modification of the first embodiment. FIG. 10 is an explanatory diagram showing an XZ cross-sectional configuration for fastening a fuel cell stack 100c according to a third modification of the first embodiment. It is a perspective view showing the appearance composition of fuel cell hot module 10 in a 2nd embodiment. It is explanatory drawing which shows the XZ sectional structure of the electric power generation module 20 in the position of XVI-XVI of FIG. It is explanatory drawing which shows the YZ sectional structure of the electric power generation module 20 in the position of XVII-XVII of FIG. It is explanatory drawing which shows the XY sectional structure for fastening of the electric power generation module 20 in 2nd Embodiment. It is explanatory drawing which shows the XZ sectional structure for fastening of the electric power generation module 20 in 2nd Embodiment. It is a perspective view showing the appearance composition of hot module 10f in a modification of a 2nd embodiment. It is explanatory drawing which shows the XY cross-sectional structure of the auxiliary device 200f in the modification of 2nd Embodiment.

A. First embodiment:
A-1. Constitution:
(Configuration of Fuel Cell Stack 100)
1 to 5 are explanatory diagrams schematically showing the configuration of the fuel cell stack 100 in the present embodiment. FIG. 1 shows an external configuration of the fuel cell stack 100, FIG. 2 shows a plan configuration of an upper side of the fuel cell stack 100, and FIG. FIG. 4 shows a cross-sectional configuration of the fuel cell stack 100 at the position of IV-IV in FIGS. 1 to 3, and FIG. 5 shows a cross-sectional configuration in FIGS. 1 to 3. The cross-sectional configuration of the fuel cell stack 100 at the position VV is shown. Each drawing shows XYZ axes orthogonal to each other for specifying the direction. In the present specification, for the sake of convenience, the positive direction of the Z axis is referred to as an upward direction, and the negative direction of the Z axis is referred to as a downward direction. However, the fuel cell stack 100 is actually oriented in a direction different from such a direction. It may be installed. The same applies to FIG. 6 and subsequent figures.

  The fuel cell stack 100 includes a plurality of (seven in the present embodiment) power generation units 102 and a pair of end plates 104 and 106. The seven power generation units 102 are arranged side by side in a predetermined arrangement direction (vertical direction in the present embodiment). The pair of end plates 104 and 106 are arranged so as to sandwich the seven power generation units 102 from above and below. Note that the arrangement direction (vertical direction) corresponds to the first direction in the claims.

  As shown in FIG. 1, holes penetrating in the vertical direction are formed at four corners on the outer periphery around the Z direction of each power generation unit 102, and holes formed in each layer and corresponding to each other are formed in the vertical direction. A bolt hole 109 extending in the up-down direction is formed in communication. A bolt 22 is inserted into each bolt hole 109, and the fuel cell stack 100 is fastened by each bolt 22. The configuration for fastening the fuel cell stack 100 will be described later in detail.

  As shown in FIGS. 1, 2, 4, and 5, a vertically penetrating hole is formed near the midpoint of the outer periphery of each power generation unit 102 and lower end plate 106 around the Z direction. The holes formed in each layer communicate with each other in the vertical direction to form a communication hole 108 extending in the vertical direction over each power generation unit 102 and the end plate 106.

  As shown in FIGS. 1, 2 and 4, the midpoint of one side (side of two sides parallel to the Y-axis on the X-axis positive direction side) on the outer periphery of the fuel cell stack 100 around the Z-direction. The communication hole 108 located in the vicinity functions as an oxidant gas introduction manifold 161 which is a gas flow path into which the oxidant gas OG is introduced from outside the fuel cell stack 100 and supplies the oxidant gas OG to each power generation unit 102. The communication hole 108 located near the midpoint of the opposite side (side of the two sides parallel to the Y axis on the negative side of the X axis) is connected to the air chamber 166 of each power generation unit 102. It functions as an oxidant gas discharge manifold 162 that is a gas flow path that discharges the oxidant off-gas OOG that is the discharged gas to the outside of the fuel cell stack 100. In this embodiment, for example, air is used as the oxidizing gas OG.

  As shown in FIGS. 1, 2 and 5, one side (side of two sides parallel to the X-axis on the Y-axis positive direction side) of the outer periphery of the fuel cell stack 100 around the Z-direction. The communication hole 108 located near the middle point functions as a fuel gas introduction manifold 171 which is a gas flow path through which the fuel gas FG is introduced from outside the fuel cell stack 100 and supplies the fuel gas FG to each power generation unit 102. The communication hole 108 located near the midpoint of the opposite side (side of the two sides parallel to the X axis, the side on the negative side of the Y axis) is discharged from the fuel chamber 176 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 extracted gas, to the outside of the fuel cell stack 100. In the present embodiment, for example, a hydrogen-rich gas obtained by reforming city gas is used as the fuel gas FG.

  As shown in FIGS. 1 and 3 to 5, the fuel cell stack 100 is provided with four gas passage members 27. Each gas passage member 27 has a hollow cylindrical main body portion 28 and a hollow cylindrical branch portion 29 branched from a side surface of the main body portion 28. The hole of the branch part 29 communicates with the hole of the main body part 28. A gas pipe (not shown) is connected to the branch portion 29 of each gas passage member 27. As shown in FIG. 4, the hole of the main body 28 of the gas passage member 27 disposed at the position of the oxidizing gas introduction manifold 161 communicates with the oxidizing gas introduction manifold 161 and the oxidizing gas discharge manifold 162 The hole of the main body 28 of the gas passage member 27 arranged at the position communicates with the oxidizing gas discharge manifold 162. As shown in FIG. 5, a hole of the main body 28 of the gas passage member 27 disposed at the position of the fuel gas introduction manifold 171 communicates with the fuel gas introduction manifold 171, and the position of the fuel gas discharge manifold 172. The hole of the main body portion 28 of the gas passage member 27 disposed at a position communicates with the fuel gas discharge manifold 172. The insulating sheet 26 is interposed between each gas passage member 27 and the surface of the end plate 106. The insulating sheet 26 is made of, for example, a mica sheet, a ceramic fiber sheet, a ceramic green sheet, a glass sheet, a glass ceramic composite, or the like.

(Configuration of End Plates 104 and 106)
The pair of end plates 104 and 106 are conductive members in the shape of a rectangular flat plate, and are made of, for example, a stainless material or an aluminum-added stainless material. One end plate 104 is arranged above the uppermost power generation unit 102, and the other end plate 106 is arranged below the lowermost power generation unit 102. A plurality of power generation units 102 are held in a state of being pressed by a pair of end plates 104 and 106. The upper end plate 104 functions as a positive output terminal of the fuel cell stack 100, and the lower end plate 106 functions as a negative output terminal of the fuel cell stack 100.

(Configuration of the power generation unit 102)
6 to 9 are explanatory diagrams illustrating the detailed configuration of the power generation unit 102. FIG. FIG. 6 illustrates a cross-sectional configuration of two power generation units 102 adjacent to each other at the same position as the cross section illustrated in FIG. 4, and FIG. 7 illustrates adjacent cross sections at the same position as the cross section illustrated in FIG. 5. FIG. 8 illustrates a cross-sectional configuration of the two power generation units 102, FIG. 8 illustrates a cross-sectional configuration of the power generation unit 102 at a position VIII-VIII in FIG. 6, and FIG. The sectional configuration of the power generation unit 102 at the position IX is shown.

  As shown in FIGS. 6 and 7, the power generation unit 102, which is the minimum unit of power generation, includes a single cell 110, a separator 120, an air electrode side frame 130, an air electrode side current collector 134, and a fuel electrode side frame. 140, a fuel electrode side current collector 144, and a pair of interconnectors 150 forming the uppermost layer and the lowermost layer of the power generation unit 102. The separator 120, the air electrode side frame 130, the fuel electrode side frame 140, and the periphery of the interconnector 150 around the Z direction have holes corresponding to the bolt holes 109 into which the bolts 22 are inserted, and function as manifolds. A hole corresponding to the communication hole 108 is formed (see FIGS. 8 and 9).

  The single cell 110 includes an electrolyte layer 112, and an air electrode (cathode) 114 and a fuel electrode (anode) 116 that are opposed to each other in the vertical direction (the direction in which the power generation units 102 are arranged) across the electrolyte layer 112. The unit cell 110 of the present embodiment is a unit cell of an anode supporting type in which the anode 116 supports the electrolyte layer 112 and the cathode 114.

  The electrolyte layer 112 is a rectangular plate-shaped member, for example, YSZ (yttria-stabilized zirconia), ScSZ (scandia-stabilized zirconia), SDC (samarium-doped ceria), GDC (gadolinium-doped ceria), perovskite-type oxide, and the like. Of solid oxide. The air electrode 114 is a rectangular plate-shaped member, and is formed of, for example, a perovskite-type oxide (for example, LSCF (lanthanum strontium cobalt iron oxide), LSM (lanthanum strontium manganese oxide), LNF (lanthanum nickel iron)). ing. The fuel electrode 116 is a rectangular plate-shaped member, and is formed of, for example, Ni (nickel), a cermet made 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) using a solid oxide as an electrolyte.

  The separator 120 is a frame-shaped member in which a rectangular hole 121 penetrating vertically is formed near the center, and is formed of, for example, metal. The peripheral portion of the hole 121 in the separator 120 faces the peripheral portion of the surface of the electrolyte layer 112 on the air electrode 114 side. The separator 120 is joined to the electrolyte layer 112 (single cell 110) by a joining portion 124 formed of a brazing material (for example, Ag brazing) disposed at a portion facing the separator 120. The separator 120 divides the air chamber 166 facing the air electrode 114 and the fuel chamber 176 facing the fuel electrode 116, and prevents gas leakage from one electrode side to the other electrode side at the peripheral portion of the single cell 110. Is suppressed. Note that the unit cell 110 to which the separator 120 is joined is also referred to as a unit cell with a separator.

  The interconnector 150 is a rectangular plate-shaped conductive member, and is formed of, for example, ferritic stainless steel. The interconnector 150 is arranged so as to face the unit cell 110 in the arrangement direction. The interconnector 150 secures electrical continuity between the power generation units 102 and prevents mixing of reaction gas between the power generation units 102. In this embodiment, when two power generation units 102 are arranged adjacent to each other, one interconnector 150 is shared by two adjacent power generation units 102. That is, the upper interconnector 150 in a certain power generation unit 102 is the same member as the lower interconnector 150 in another power generation unit 102 adjacent to the upper side of the power generation unit 102. Further, since the fuel cell stack 100 includes the pair of end plates 104 and 106, the power generation unit 102 located at the uppermost position in the fuel cell stack 100 does not have the upper interconnector 150 and is located at the lowermost position. The power generation unit 102 does not include the lower interconnector 150 (see FIGS. 4 and 5).

  As shown in FIG. 8, the air electrode-side frame 130 is a frame-shaped member having a rectangular hole 131 penetrating in the vertical direction in the vicinity of the center, and is formed of, for example, an insulator such as mica. The air electrode side frame 130 is disposed between the separator 120 and the interconnector 150, and faces the peripheral edge of the surface of the separator 120 opposite to the side facing the electrolyte layer 112 and faces the air electrode 114 of the interconnector 150. In contact with the peripheral edge of the surface on the side to be cleaned. The hole 131 of the cathode side frame 130 forms an air chamber 166 facing the cathode 114. Further, the pair of interconnectors 150 included in the power generation unit 102 is electrically insulated by the air electrode side frame 130. Further, the air electrode side frame 130 has an oxidizing gas supply communication hole 132 that connects the oxidizing gas introduction manifold 161 and the air chamber 166, and an oxidizing gas that connects the air chamber 166 and the oxidizing gas discharge manifold 162. A discharge communication hole 133 is formed.

  As shown in FIG. 9, the fuel electrode side frame 140 is a frame-like member having a rectangular hole 141 penetrating in the vertical direction near the center, and is formed of, for example, metal. The fuel electrode side frame 140 is disposed between the separator 120 and the interconnector 150, and has a peripheral portion of a surface of the separator 120 facing the electrolyte layer 112 and a surface of the interconnector 150 facing the fuel electrode 116. Is in contact with the peripheral edge of The hole 141 of the fuel electrode side frame 140 forms a fuel chamber 176 facing the fuel electrode 116. Further, the fuel electrode side frame 140 has a fuel gas supply communication hole 142 communicating the fuel gas introduction manifold 171 and the fuel chamber 176, and a fuel gas discharge communication hole 143 communicating the fuel chamber 176 and the fuel gas discharge manifold 172. Are formed.

  As shown in FIG. 8, the air electrode side current collector 134 is arranged in the air chamber 166. The cathode-side current collector 134 is composed of a plurality of substantially quadrangular prism-shaped conductive members arranged at predetermined intervals, and is formed of, for example, ferritic stainless steel. The air electrode side current collector 134 contacts the surface of the air electrode 114 on the side opposite to the side facing the electrolyte layer 112 and the surface of the interconnector 150 on the side opposite to the air electrode 114, thereby forming the air electrode 114. 114 and the interconnector 150 are electrically connected. The air electrode side current collector 134 and the interconnector 150 may be formed as an integral member.

  As shown in FIG. 9, the fuel electrode side current collector 144 is disposed in the fuel chamber 176. The fuel electrode side current collector 144 includes an interconnector facing portion 146, a plurality of electrode facing portions 145, and a connecting portion 147 connecting each electrode facing portion 145 and the interconnector facing portion 146. And a nickel alloy, stainless steel, or the like. Each electrode facing portion 145 contacts the surface of the anode 116 opposite to the side facing the electrolyte layer 112, and the interconnector facing portion 146 contacts the surface of the interconnect 150 facing the anode 116. I do. Therefore, the fuel electrode side current collector 144 electrically connects the fuel electrode 116 and the interconnector 150. Note that a spacer 149 formed of, for example, mica is disposed between the electrode facing portion 145 and the interconnector facing portion 146. Therefore, the anode-side current collector 144 follows the deformation of the power generation unit 102 due to the temperature cycle and the reaction gas pressure fluctuation, and the electrical connection between the anode 116 and the interconnector 150 via the anode-side current collector 144 is made. Well maintained.

A-2. Operation of the fuel cell stack 100:
As shown in FIG. 4, FIG. 6 and FIG. 8, the oxidizing gas is supplied through a gas pipe (not shown) connected to a branch portion 29 of a gas passage member 27 provided at the position of the oxidizing gas introducing manifold 161. When the OG is supplied, the oxidizing gas OG is introduced into the oxidizing gas introduction manifold 161 through the branch portion 29 of the gas passage member 27 and the hole of the main body 28, and is supplied from the oxidizing gas introduction manifold 161 to each power generation unit. The air is supplied to the air chamber 166 through the oxidizing gas supply communication hole 132 of the nozzle 102. As shown in FIGS. 5, 7 and 9, the fuel gas is supplied via a gas pipe (not shown) connected to a branch portion 29 of a gas passage member 27 provided at the position of the fuel gas introduction manifold 171. When the FG is supplied, the fuel gas FG is introduced into the fuel gas introduction manifold 171 through the branch portion 29 of the gas passage member 27 and the hole of the main body 28, and the fuel gas FG of each power generation unit 102 is supplied from the fuel gas introduction manifold 171. The fuel is supplied to the fuel chamber 176 through the gas supply communication hole 142.

  When the oxidizing gas OG is supplied to the air chamber 166 of each power generation unit 102 and the fuel gas FG is supplied to the fuel chamber 176, power generation is performed in the single cell 110 by an electrochemical reaction of the oxidizing gas OG and the fuel gas FG. Will be 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 of the interconnectors 150 via the air electrode current collector 134, and the fuel electrode 116 is connected via the fuel electrode current collector 144. It is electrically connected to the other interconnector 150. The plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. Therefore, electric energy generated in each power generation unit 102 is extracted from the end plates 104 and 106 functioning as output terminals of the fuel cell stack 100. Since the SOFC generates electric power at a relatively high temperature (for example, 700 ° C. to 1000 ° C.), the fuel cell stack 100 is heated (heated) until the high temperature can be maintained by the heat generated by the electric power generation after startup. (Not shown).

  The oxidant off-gas OOG discharged from the air chamber 166 in each power generation unit 102 is supplied from the air chamber 166 through the oxidant gas discharge communication hole 133 as shown in FIGS. The gas is discharged to the gas discharge manifold 162 and further connected to the branch portion 29 through the holes of the main body 28 and the branch portion 29 of the gas passage member 27 provided at the position of the oxidizing gas discharge manifold 162 (FIG. (Not shown) to the outside of the fuel cell stack 100. Further, the fuel off-gas FOG, which is the gas discharged from the fuel chamber 176 in each power generation unit 102, is supplied from the fuel chamber 176 through the fuel gas discharge communication hole 143 as shown in FIGS. The gas is discharged to the discharge manifold 172, and further passes through a hole of the main body 28 and the branch 29 of the gas passage member 27 provided at the position of the fuel gas discharge manifold 172, and is connected to the gas pipe (not shown). Through the fuel cell stack 100.

  In the fuel cell stack 100 of the present embodiment, as described above, a plurality of manifolds (communication holes 108) are formed separately from the plurality of bolt holes 109, so that the contaminants contained in the bolts 22 can be removed from each manifold. Is carried to the fuel chamber 176 or the air chamber 166 by the gas flow in the above, and it is possible to avoid the occurrence of the poisoning phenomenon in which the reaction speed of the electrode is reduced by adhering to the fuel electrode 116 or the air electrode 114 and each bolt 22 is When the bolts 22 are exposed to gases having different temperatures, a difference occurs in the amount of deformation due to the thermal expansion of each bolt 22, and the contact pressure of the fuel cell stack 100 fluctuates in the plane direction of the fuel cell stack 100. Gas leakage can be avoided.

A-3. Configuration for fastening fuel cell stack 100:
FIG. 10 is an explanatory diagram showing a configuration for fastening the fuel cell stack 100. As shown in FIG. FIG. 10 shows a cross-sectional configuration of the fuel cell stack 100 at a position XX in FIGS. 1 to 3. As described above, the fuel cell stack 100 is fastened by the plurality of bolts 22. As shown in FIG. 10, the bolt 22 includes a shaft 226 and a flange 228 formed at one (upper side in this embodiment) end of the shaft 226. The shaft 226 and the flange 228 are an integral member. The flange portion 228 is a portion having a larger diameter (dimension in a direction orthogonal to the axial direction of the shaft portion 226) than the shaft portion 226, and has a seat surface 229. The seat surface 229 is a surface on the shaft portion 226 side of a surface of the flange portion 228 orthogonal to the axial direction of the shaft portion 226. A screw portion 224 is formed at an end of the shaft portion 226 of the bolt 22 opposite to the flange portion 228. A male screw is formed on the outer peripheral surface of the screw part 224.

  The bolt holes 109 include a through hole formed in each power generation unit 102 and a through hole formed in the upper end plate 104. A screw hole 107 communicating with the bolt hole 109 is formed in the lower end plate 106. The screw hole 107 penetrates the lower end plate 106 in the vertical direction, and a female screw is formed on an inner peripheral surface thereof.

  The bolt 22 is inserted into the bolt hole 109, and a screw portion 224 formed on the shaft portion 226 of the bolt 22 is screwed into a screw hole 107 formed on the lower end plate 106. In this state, the shaft portion 226 of the bolt 22 is in a posture extending in the up-down direction (Z-axis direction). The flange portion 228 is located above the shaft portion 226 (on the positive side in the Z-axis direction), and the seating surface 229 of the flange portion 228 is in contact with the upper surface of the upper end plate 104.

  Further, with respect to the vertical position, the position of the lower end of the screw portion 224 of the bolt 22 is the same as the position of the lower end of the screw hole 107. Such a configuration can be realized by setting the length of the bolt 22 in consideration of the thickness of the power generation unit 102 and the end plates 104 and 106 and the amount of deformation due to the fastening load. Alternatively, it can also be realized by setting the length of the bolt 22 to be longer, and cutting the portion of the screw portion 224 that penetrates the screw hole 107 and protrudes downward after fastening.

  Although FIG. 10 shows a cross section of the fuel cell stack 100 at one bolt hole 109, the cross section of the fuel cell stack 100 at the other three bolt holes 109 has the same configuration. . Therefore, a total of four screw holes 107 are formed in the lower end plate 106, and the screw portion 224 of the bolt 22 is screwed into each screw hole 107. The fuel cell stack 100 is fastened by the bolts 22 screwed into the screw holes 107.

  Since the fuel cell stack 100 of the present embodiment has the above-described configuration for fastening, it is possible to suppress the occurrence of gas leakage and contact failure. FIG. 11 is an explanatory diagram illustrating a configuration for fastening the fuel cell stack 100 ′ of the comparative example. In the fuel cell stack 100 'of the comparative example shown in FIG. 11, the fuel cell stack 100' is fastened by the bolts 22 and the nuts 24 fitted to the bolts 22. In this comparative example, the seat surface 249 of the nut 24 is in contact with the lower surface of the lower end plate 106. For this reason, fastening stress concentrates on a contact portion of the lower end plate 106 with the seat surface 249, and the end plate 106 is locally deformed to reduce the fastening force, which may cause gas leakage or poor contact. In particular, when the fastening force is large or when the fastening state is maintained for a long period of time, the possibility is remarkable.

  On the other hand, in the fuel cell stack 100 of the present embodiment, the plurality of screw holes 107 are formed in the lower end plate 106, and the screw portion 224 formed in the shaft portion 226 of each bolt 22 is It is screwed into each screw hole 107 of the end plate 106 on the side. Therefore, the fastening force is generated directly on the lower end plate 106, and the concentration of the fastening stress on a part of the end plate 106 is avoided. Thus, local deformation of the end plate 106 can be suppressed, and occurrence of gas leakage and poor contact can be suppressed.

  Further, in the fuel cell stack 100 of the present embodiment, regarding the configuration near the upper end plate 104, since the shaft portion 226 and the flange portion 228 of the bolt 22 are an integral member, for example, the flange portion 228 is Compared to a configuration in which a nut is formed separately and the shaft portion 226 of the bolt 22 and the nut are screwed together, the number of screwed portions is reduced, so that the management of the fastening load can be facilitated and long-term use is possible. Can be prevented from loosening at the threaded portion.

  In the fuel cell stack 100 of the present embodiment, the position of the lower end of the screw portion 224 of the bolt 22 is the same as the position of the lower end of the screw hole 107 formed in the end plate 106 with respect to the vertical position. I have. Therefore, as compared with a configuration in which the lower end of the screw portion 224 is located above the lower end of the screw hole 107 (a configuration in which the screw portion 224 is inserted only halfway through the screw hole 107), the screw portion 224 and the screw Since the number of bites in the screwed portion with the hole 107 can be made constant and increased, the fastening force can be stabilized, and the durability of the screwed portion can be improved. In addition, as compared with a configuration in which the lower end of the screw portion 224 is located below the lower end of the screw hole 107 (a configuration in which the tip of the screw portion 224 protrudes from the lower side of the screw hole 107), The weight can be reduced, and as a result, the fuel cell stack 100 can be reduced in weight.

  Note that the closer the coefficient of thermal expansion of the bolt 22 and the coefficient of thermal expansion of the end plates 104 and 106 are, the more preferable it is because variation in the fastening load due to the difference in the amount of thermal expansion between the respective members can be suppressed. For example, it is preferable that the bolt 22 is formed of an Inconel material and the end plates 104 and 106 are formed of a stainless material or an aluminum-added stainless material.

  In this embodiment, the bolt 22, the upper end plate 104, the lower end plate 106, and the fuel cell stack 100 are respectively a fastening member, a first member, and a 2 and a fuel cell structure.

A-4. Modification of the first embodiment:
FIG. 12 is an explanatory diagram showing a configuration for fastening the fuel cell stack 100a in the first modification of the first embodiment. In the modification shown in FIG. 12, with respect to the vertical position, the lower end of the screw portion 224 of the bolt 22 is located below the lower end of the screw hole 107. The other configuration is the same as that of the first embodiment shown in FIG. 10, and the description thereof will be omitted by retaining the same reference numerals.

  In the fuel cell stack 100a according to the first modification of the first embodiment, a plurality of screw holes 107 are formed in the lower end plate 106 as in the first embodiment described above, and the shaft of each bolt 22 is formed. A screw portion 224 formed in the portion 226 is screwed into each screw hole 107 of the lower end plate 106. Therefore, the concentration of the fastening stress on a part of the end plate 106 can be avoided, the local deformation of the end plate 106 can be suppressed, and the occurrence of gas leakage and contact failure can be suppressed.

  Further, in the fuel cell stack 100a according to the first modified example of the first embodiment, the shaft portion 226 and the flange portion 228 of the bolt 22 are integrated members as in the first embodiment described above. The number of locations is reduced, the management of the fastening load can be facilitated, and the loosening of the threaded locations during long-term use can be suppressed.

  In the fuel cell stack 100a according to the first modification of the first embodiment, the position of the lower end of the screw portion 224 of the bolt 22 is set at the lower end of the screw hole 107 formed in the end plate 106 with respect to the vertical position. Since the position is lower than the position, the lower end position of the screw portion 224 is higher than the lower end position of the screw hole 107 (the structure in which the screw portion 224 is inserted only halfway through the screw hole 107). As compared with, the number of bites at the screwing portion between the screw portion 224 and the screw hole 107 can be constant and increased, so that the fastening force can be stabilized, and Can be improved in durability.

  FIG. 13 is an explanatory diagram illustrating a configuration for fastening the fuel cell stack 100b in the second modification of the first embodiment. In the modification shown in FIG. 13, the position of the lower end of the screw portion 224 of the bolt 22 is located above the position of the lower end of the screw hole 107 with respect to the vertical position. The other configuration is the same as that of the first embodiment shown in FIG. 10, and the description thereof will be omitted by retaining the same reference numerals.

  In the fuel cell stack 100b according to the second modification of the first embodiment, a plurality of screw holes 107 are formed in the lower end plate 106 as in the first embodiment described above, and the shaft of each bolt 22 is formed. A screw portion 224 formed in the portion 226 is screwed into each screw hole 107 of the lower end plate 106. Therefore, the concentration of the fastening stress on a part of the end plate 106 can be avoided, the local deformation of the end plate 106 can be suppressed, and the occurrence of gas leakage and contact failure can be suppressed.

  Further, in the fuel cell stack 100b according to the second modification of the first embodiment, the shaft portion 226 and the flange portion 228 of the bolt 22 are integrated members as in the first embodiment described above. The number of locations is reduced, the management of the fastening load can be facilitated, and the loosening of the threaded locations during long-term use can be suppressed.

  FIG. 14 is an explanatory diagram illustrating a configuration for fastening the fuel cell stack 100c according to the third modification of the first embodiment. In the modified example shown in FIG. 14, the flange portion 228 does not exist on the bolt 22, and instead, the nut 24 screwed into the screw portion 227 formed at the upper end of the shaft portion 226 of the bolt 22 functions as the flange portion. . The other configuration is the same as that of the first embodiment shown in FIG. 10, and the description thereof will be omitted by retaining the same reference numerals. In this modification, the bolt 22 and the nut 24 correspond to a fastening member in the claims.

  In the fuel cell stack 100c according to the third modified example of the first embodiment, the seat surface 249 of the nut 24 screwed to each bolt 22 is located on the upper side of the upper end plate 104, as in the first embodiment. A plurality of screw holes 107 are formed in the lower end plate 106 in contact with the surface, and a screw portion 224 formed in the shaft portion 226 of each bolt 22 is connected to each screw hole in the lower end plate 106. 107 is screwed. Therefore, the concentration of the fastening stress on a part of the end plate 106 can be avoided, the local deformation of the end plate 106 can be suppressed, and the occurrence of gas leakage and contact failure can be suppressed.

B. Second embodiment:
B-1. Constitution:
(Configuration of Fuel Cell Hot Module 10)
FIG. 15 is an explanatory diagram schematically showing a configuration of a fuel cell hot module (hereinafter, referred to as “hot module”) 10 in the second embodiment. In FIG. 15, in order to make the configuration of the hot module 10 easy to understand, some components are shown transparently or some components are not shown. The hot module 10 includes a power generation module 20, a heat insulating container 30 that houses the power generation module 20, and various pipes 232, 234, 236, and 238 connected to the power generation module 20. The hot module 10 may include a heater (for example, a gas burner) that heats the power generation module 20 at the time of startup or the like.

(Configuration of Insulated Container 30)
The heat insulating container 30 has a configuration in which a heat insulating material is disposed on an inner surface of a housing formed of, for example, stainless steel. Since the power generation module 20 is housed in the heat insulating container 30, the power generation module 20 is maintained at a high temperature when generating power.

(Configuration of power generation module 20)
FIG. 16 and FIG. 17 are explanatory diagrams schematically showing the configuration of the power generation module 20 in the second embodiment. FIG. 16 shows a cross-sectional configuration of the power generation module 20 at the position of XVI-XVI in FIG. 15, and FIG. 17 shows a cross-sectional configuration of the power generation module 20 at the position of XVII-XVII in FIG. I have. As shown in FIGS. 15 to 17, the power generation module 20 includes a fuel cell stack 100e and an auxiliary device 200 disposed below the fuel cell stack 100e.

(Configuration of Fuel Cell Stack 100e)
The fuel cell stack 100e of the second embodiment differs from the fuel cell stack 100 of the first embodiment in that bolts 22 are inserted not only into the respective bolt holes 109 but also into the respective communication holes 108 forming the manifold. . Specifically, the bolt 22 is inserted into each communication hole 108, and the space formed between the inner peripheral surface of the communication hole 108 and the outer peripheral surface of the shaft portion 226 of the bolt 22 is used as each manifold. Further, the fuel cell stack 100e of the second embodiment also differs from the first embodiment in the configuration for fastening described later. The other configuration of the fuel cell stack 100e according to the second embodiment is the same as the configuration of the fuel cell stack 100 according to the above-described first embodiment.

(Configuration of auxiliary device 200)
The auxiliary device 200 includes a box-shaped auxiliary device main body 210 and a fixing portion 220 formed on a side surface of the auxiliary device main body 210. The auxiliary device 200 is formed of, for example, a stainless material or an aluminum-added stainless material.

  The fixing part 220 is shaped so as to project from the side surface of the auxiliary device main body 210 in a direction perpendicular to the up-down direction. The positions of the upper ends of the auxiliary device main body 210 and the fixing part 220 are the same. That is, the upper surface of the auxiliary device 200 is constituted by the upper surface of the auxiliary device main body 210 and the upper surface of the fixing portion 220. At the position corresponding to each communication hole 108 and each bolt hole 109 of the fuel cell stack 100e in the fixing portion 220, a hole 208 communicating with the communication hole 108 or the bolt hole 109 is formed.

  The interior of the auxiliary device main body 210 is divided into two parts by the two partition walls 222, a primary combustion chamber 212, a reforming chamber 214 arranged below the primary combustion chamber 212, and a secondary combustion chamber arranged below the reforming chamber 214. And a room 216. The primary combustion chamber 212 is a chamber for mixing and burning the oxidant off-gas OOG and the fuel off-gas FOG discharged from the fuel cell stack 100 e, and through the hole 208 formed in the fixing part 220, It is in communication with the gas exhaust manifold 162 and the fuel gas exhaust manifold 172. The secondary combustion chamber 216 is a chamber for further burning the oxidant off-gas OOG and the fuel off-gas FOG mixed and burned in the primary combustion chamber 212, and a flow passage 218 vertically passing through the reforming chamber 214. Through the primary combustion chamber 212. In one or both of the primary combustion chamber 212 and the secondary combustion chamber 216, a catalyst for promoting the combustion of the oxidant off-gas OOG and the fuel off-gas FOG is arranged.

  The reforming chamber 214 is a chamber for reforming the raw fuel gas RFG to generate a hydrogen-rich fuel gas FG, and communicates with the fuel gas introduction manifold 171 through a hole 208 formed in the fixing part 220. are doing. In the reforming chamber 214, a catalyst for promoting the reforming reaction is arranged.

(Configuration of various pipes 232, 234, 236, 238)
An oxidizing gas introduction pipe 232 into which the oxidizing gas OG is introduced, a raw fuel gas introducing pipe 234 into which the raw fuel gas RFG is introduced, and the reforming water RW are introduced into the auxiliary device 200 of the power generation module 20. The reforming water introduction pipe 236 and the exhaust gas discharge pipe 238 from which the exhaust gas EG is discharged are connected. The oxidizing gas introduction pipe 232 communicates with the oxidizing gas introduction manifold 161 via a hole 208 formed in the fixing part 220. The raw fuel gas introduction pipe 234 and the reforming water introduction pipe 236 communicate with the reforming chamber 214 of the auxiliary device main body 210, and the exhaust gas discharge pipe 238 communicates with the secondary combustion chamber 216 of the auxiliary device main body 210. are doing.

B-2. Operation of the power generation module 20:
As shown in FIG. 16, the oxidizing gas OG is introduced into the oxidizing gas introducing manifold 161 from the oxidizing gas introducing pipe 232 through a hole 208 formed in the fixing portion 220, and the oxidizing gas is introduced from the oxidizing gas introducing manifold 161. The air is supplied to the air chamber 166 of each power generation unit 102. As shown in FIG. 17, the raw fuel gas RFG (city gas) and the reforming water RW are supplied from the raw fuel gas introducing pipe 234 and the reforming water introducing pipe 236, respectively, to the reforming chamber 214 of the auxiliary device main body 210. And is subjected to a reforming reaction. The fuel gas FG generated along with the reforming reaction in the reforming chamber 214 is introduced into the fuel gas introduction manifold 171 through the hole 208 formed in the fixed part 220 of the auxiliary device 200, and is supplied from the fuel gas introduction manifold 171 to The fuel is supplied to the fuel chamber 176 of the power generation unit 102.

  When the oxidizing gas OG is supplied to the air chamber 166 of each power generation unit 102 and the fuel gas FG is supplied to the fuel chamber 176, power generation is performed in each power generation unit 102 as in the first embodiment. As shown in FIG. 16, the oxidant off-gas OOG discharged from the air chamber 166 in each power generation unit 102 passes through the oxidant gas discharge manifold 162 from the air chamber 166 and the hole 208 formed in the fixing part 220 as shown in FIG. Is discharged to the primary combustion chamber 212 of the auxiliary device main body 210. Further, the fuel off-gas FOG, which is the gas discharged from the fuel chamber 176 in each power generation unit 102, passes from the fuel chamber 176 through a hole 208 formed in the fuel gas discharge manifold 172 and the fixing part 220 as shown in FIG. Is discharged to the primary combustion chamber 212 of the auxiliary device main body 210. The oxidant off-gas OOG and the fuel off-gas FOG discharged into the primary combustion chamber 212 are mixed and burned in the primary combustion chamber 212, guided to the secondary combustion chamber 216 via the flow path 218, and further combusted. It is discharged to the outside of the hot module 10 through the pipe 238. The reforming reaction in the reforming chamber 214 is promoted by the heat generated in the primary combustion chamber 212 and the secondary combustion chamber 216, and the power generation module 20 is maintained at a high temperature.

B-3. Configuration for fastening power generation module 20:
FIG. 18 and FIG. 19 are explanatory diagrams illustrating a configuration for fastening the power generation module 20 in the second embodiment. FIG. 18 shows a plan configuration on the upper side of the auxiliary device 200, and FIG. 19 shows a cross-sectional configuration of the power generation module 20 at the position of XIX-XIX in FIGS.

  As shown in FIG. 19, the bolt holes 109 include through holes formed in each power generation unit 102 and through holes formed in the pair of end plates 104 and 106. In addition, the bolt hole 109 communicates with a hole 208 formed at a position corresponding to the bolt hole 109 in the fixing portion 220. A screw hole 221 communicating with the hole 208 is formed below the hole 208 in the fixing portion 220. A female screw is formed on the inner peripheral surface of the screw hole 221. The hole in which the hole 208 and the screw hole 221 are integrated passes through the fixing portion 220 in the up-down direction.

  The bolt 22 inserted into the bolt hole 109 reaches a hole 208 formed in the fixing part 220, and a screw part 224 formed in the shaft part 226 of the bolt 22 is formed below the hole 208 in the fixing part 220. Screw holes 221. In this state, the shaft portion 226 of the bolt 22 is in a posture extending in the up-down direction (Z-axis direction). The flange portion 228 is located above the shaft portion 226 (on the positive side in the Z-axis direction), and the seating surface 229 of the flange portion 228 is in contact with the upper surface of the upper end plate 104. Further, with respect to the vertical position, the position of the lower end of the screw portion 224 of the bolt 22 is the same as the position of the lower end of the screw hole 221.

  Although FIG. 19 shows a cross section of the power generation module 20 at one bolt hole 109, the cross section of the power generation module 20 at the other three bolt holes 109 has the same configuration.

  As shown in FIGS. 16 and 17, each communication hole 108 functioning as a manifold includes a through hole formed in each power generation unit 102 and a through hole formed in a pair of end plates 104 and 106. Have been. Further, each communication hole 108 communicates with a hole 208 formed at a position corresponding to each communication hole 108 in the fixing portion 220. A screw hole 221 communicating with the hole 208 is formed below the hole 208 in the fixing portion 220. A female screw is formed on the inner peripheral surface of the screw hole 221. At the position of the communication hole 108, unlike the configuration of the position of the bolt hole 109 shown in FIG. 19, the screw hole 221 does not reach the lower surface of the fixing part 220, and the fixing part 220 is Does not penetrate in the direction.

  The bolt 22 inserted into each communication hole 108 reaches the hole 208 formed in the fixing part 220, and the screw part 224 formed in the shaft part 226 of the bolt 22 is formed below the hole 208 in the fixing part 220. Screwed into the screw hole 221. In this state, the shaft portion 226 of the bolt 22 is in a posture extending in the up-down direction (Z-axis direction). Further, the flange portion 228 is located on the upper side (the positive side in the Z-axis direction) with respect to the shaft portion 226, and the seating surface 229 of the flange portion 228 has an insulating sheet 26 arranged to ensure airtightness of the manifold. , And is in contact with the upper surface of the upper end plate 104.

  As shown in FIG. 18, the fixing portion 220 of the auxiliary device 200 is provided with four screw holes 221 provided at positions corresponding to the four bolt holes 109 and at positions corresponding to the four communication holes 108. A total of eight screw holes 221 are formed with the four screw holes 221, and the screw portion 224 of the bolt 22 is screwed into each screw hole 221. Thereby, the auxiliary device 200 and the fuel cell stack 100e are fixed, and the power generation module 20 is fastened.

  As described above, in the power generation module 20 of the present embodiment, the bearing surface 229 of the flange portion 228 of each bolt 22 is in contact with the upper surface of the upper end plate 104 directly or via another member. . Further, a plurality of screw holes 221 are formed in the auxiliary device 200, and a screw portion 224 formed in the shaft portion 226 of each bolt 22 is screwed into each screw hole 221 of the auxiliary device 200. Therefore, the fastening force is directly generated in the auxiliary device 200, and the concentration of the fastening stress on a part of the auxiliary device 200 is avoided. Accordingly, local deformation of the auxiliary device 200 can be suppressed, and occurrence of gas leakage and poor contact can be suppressed.

  In the power generation module 20 of the present embodiment, since the shaft portion 226 and the flange portion 228 of the bolt 22 are integral members with respect to the configuration near the upper end plate 104, for example, the flange portion 228 is separate from the bolt 22. As compared with the configuration in which the shaft portion 226 of the bolt 22 and the nut are screwed together, the number of screwed portions is reduced, so that the management of the fastening load can be facilitated and the long-term use can be achieved. Looseness of the screwed portion can be suppressed.

  Further, in the power generation module 20 of the present embodiment, the position of the lower end of the screw portion 224 of the bolt 22 inserted in the bolt hole 109 with respect to the vertical position is the position of the lower end of the screw hole 221 formed in the auxiliary device 200. It is in the same position as. Therefore, as compared with a configuration in which the lower end of the screw portion 224 is located above the lower end of the screw hole 221 (a configuration in which the screw portion 224 is inserted only halfway through the screw hole 221), the screw portion 224 and the screw Since the number of bites of the screwed portion with the hole 221 can be made constant and increased, the fastening force can be stabilized, and the durability of the screwed portion can be improved. Further, compared to a configuration in which the lower end of the screw portion 224 is located below the lower end of the screw hole 221 (a configuration in which the tip end of the screw portion 224 protrudes from the lower side of the screw hole 221), Weight reduction can be achieved, and as a result, the power generation module 20 can be reduced in weight.

  The closer the thermal expansion coefficient of the bolt 22 is to the thermal expansion coefficient of the end plates 104, 106 and the auxiliary device 200, the more the variation in the fastening load due to the difference in the amount of thermal expansion of each member can be suppressed. ,preferable. For example, it is preferable that the bolt 22 is formed of an Inconel material, and the end plates 104 and 106 and the auxiliary device 200 are formed of a stainless material or an aluminum-added stainless material.

  The bolt 22, the upper end plate 104, the auxiliary device 200, and the power generation module 20 in the present embodiment are respectively connected to the fastening member, the first member, and the second member in the claims. , And a fuel cell structure.

B-4. Modification of the second embodiment:
FIG. 20 is an explanatory diagram illustrating a configuration of a hot module 10f according to a modification of the second embodiment. FIG. 21 is an explanatory diagram illustrating a configuration of an auxiliary device 200f according to a modification of the second embodiment. FIG. 20 illustrates an external configuration of the hot module 10f, and FIG. 21 illustrates a plan configuration of an upper side of the auxiliary device 200f. 20 and 21 are different from the above-described second embodiment in the configuration of the fixing portion 220f of the auxiliary device 200f and the configuration for fastening the power generation module 20f. The other configuration is the same as that of the above-described second embodiment, and the description thereof will be omitted by retaining the same reference numerals.

  As shown in FIGS. 20 and 21, in a modification of the second embodiment, the fixing portion 220f of the auxiliary device 200f is, as in the second embodiment, a direction perpendicular to the vertical direction from the side surface of the auxiliary device body 210. In addition, it protrudes to a position corresponding to the four communication holes 108. The cross-sectional configuration of the power generation module 20f at the positions of XVI-XVI and XVII-XVII in FIGS. 20 and 21 is the same as the cross-sectional configuration of the power generation module 20 of the second embodiment shown in FIGS. 16 and 17, respectively. . That is, at the position of each communication hole 108, each communication hole 108 communicates with the hole 208 formed in the fixing part 220 f of the auxiliary device 200 f, and a screw hole 221 communicating with the hole 208 is formed below the hole 208. The bolt 22 inserted into each communication hole 108 reaches the hole 208, and the screw portion 224 formed on the shaft portion 226 of the bolt 22 is screwed into the screw hole 221.

  On the other hand, as shown in FIGS. 20 and 21, in the modification of the second embodiment, the fixing portion 220 f of the auxiliary device 200 f does not protrude to the position corresponding to the four bolt holes 109. Different from form. The cross-sectional configuration of the power generation module 20f at the position XX in FIGS. 20 and 21 is the same as the cross-sectional configuration of the first embodiment illustrated in FIG. That is, at the position of each bolt hole 109, a screw hole 107 communicating with the bolt hole 109 is formed in the lower end plate 106, and formed on the shaft portion 226 of the bolt 22 inserted into the bolt hole 109. The screw portion 224 is screwed into a screw hole 107 formed in the lower end plate 106.

  As described above, in the modified example of the second embodiment, with respect to the bolts 22 inserted into the respective communication holes 108, the screw portions 224 formed on the shaft portions 226 of the respective bolts 22 are provided in the respective screw holes 221 of the auxiliary device 200f. Since the screw is engaged, concentration of fastening stress on a part of the auxiliary device 200f can be avoided, local deformation of the auxiliary device 200f can be suppressed, and occurrence of gas leakage and poor contact can be suppressed. it can. Further, as for the bolts 22 inserted into the respective bolt holes 109, the screw portions 224 formed on the shaft portions 226 of the respective bolts 22 are screwed into the respective screw holes 107 of the lower end plate 106, so that the Concentration of fastening stress on a part of the plate 106 is avoided, local deformation of the end plate 106 can be suppressed, and occurrence of gas leakage and poor contact can be suppressed.

  In addition, the bolt 22, the upper end plate 104, the lower end plate 106, the auxiliary device 200f, and the power generation module 20f in the modified example of the second embodiment are respectively connected to the fastening member in the claims. They correspond to a first member, a second member, and a fuel cell structure.

C. Other 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 also possible.

  In the first embodiment, the bolts 22 are not inserted into the communication holes 108 functioning as manifolds. However, similarly to the second embodiment, the bolts 22 are inserted into the communication holes 108, and the bolts 22 are inserted. May be screwed into a screw hole formed in the end plate 106. Conversely, in the second embodiment, the bolt 22 is inserted into each communication hole 108 functioning as a manifold. However, as in the first embodiment, the bolt 22 is not inserted into each communication hole 108. It may be. In the above-described embodiment, the space between the outer peripheral surface of the shaft portion of each bolt 22 and the inner peripheral surface of each communication hole 108 is used as each manifold. A hole may be formed in the portion in the axial direction, and the hole may be used as each manifold.

  Further, in the above embodiment, the upper end plate 104 is disposed on one side in the arrangement direction with respect to the plurality of power generation units 102, and directly on the bearing surface 229 of the flange portion 228 of the plurality of bolts 22 or other Although it functions as the first member that contacts with the member, another member may function as the first member. Further, in the first embodiment, the lower end plate 106 is disposed on the other side in the arrangement direction with respect to the plurality of power generation units 102, and the lower end plate 106 has the screw portion 224 formed on the shaft portion 226 of the plurality of bolts 22. It functions as a second member in which a plurality of screw holes to be screwed are formed. In the second embodiment, the auxiliary device 200 functions as the second member, but other members function as the second member. May work.

  Further, in the above-described embodiment, it is not necessary that the female screw is formed on the entire inner peripheral surface of the screw holes 107 and 221, as long as the female screw is formed on at least a part of the inner peripheral surface. Further, in the above-described embodiment, the configuration in which the screw holes 107 and 221 penetrate to the side opposite to the side where the bolt 22 is inserted is changed to a configuration in which the screw holes 107 and 221 do not penetrate. May be changed to a configuration that does not penetrate to the side opposite to the side where the is inserted.

  In the above-described embodiment, all the bolts 22 are configured such that the screw portions 224 of the bolts 22 are screwed into the screw holes 107 and 221 formed in the end plate 104 and the auxiliary device 200. However, at least two bolts 22 are provided. With such a configuration of the bolt 22, it is possible to suppress the occurrence of gas leakage and contact failure at least for those bolts 22. Further, in the above-described embodiment, the direction of the bolts 22 in the up-down direction may be reversed in some of the bolts 22 and the remaining bolts 22. For example, in the first embodiment, all the bolts 22 are arranged so that the screw portion 224 is on the lower side, but some of the bolts 22 are arranged so that the screw portion 224 is on the upper side. Is also good. In this case, the screw portions 224 of the bolts 22 are screwed into screw holes formed in the upper end plate 104. Further, the features of the respective modifications of the first embodiment described above can be similarly applied to the second embodiment.

  Further, in the second embodiment, the upper surface of the auxiliary device 200 is constituted by the upper surface of the auxiliary device main body 210 and the upper surface of the fixing portion 220. The uppermost surface of the container 200 may be modified to be constituted by the upper surface of the auxiliary device main body 210. In this case, the upper surface of the fixing portion 220 does not contact the lower surface of the fuel cell stack 100, but the fastening force of the bolt 22 screwed into the screw hole 221 of the fixing portion 220 causes the upper surface of the auxiliary device main body 210 to The power is transmitted to the lower surface of the fuel cell stack 100 via the power supply.

  In the second embodiment, the power generation module 20 is housed in the heat insulating container 30. However, the power generation module 20 does not need to be housed in the heat insulating container 30. In the second embodiment, the auxiliary device 200 includes the primary combustion chamber 212 for burning the gas discharged from the fuel cell stack 100 and the secondary combustion for further burning the gas burned in the primary combustion chamber 212. The auxiliary device 200 includes a chamber 216 and a reforming chamber 214 for reforming the raw fuel gas RFG to generate a fuel gas FG to be supplied to the fuel cell stack 100. It is only necessary to have at least one of the chambers 214.

  Further, in the above embodiment, the bolt 22 or the combination of the bolt 22 and the nut 24 is used as the fastening member, but another type of fastening member may be used.

  Further, in the above embodiment, the number of the power generation units 102 included in the fuel cell stack 100 is merely an example, and the number of the power generation units 102 is appropriately determined according to the output voltage required for the fuel cell stack 100 and the like. In the above embodiment, the number of bolts 22 used for fastening the fuel cell stack 100 is merely an example, and the number of bolts 22 is appropriately determined according to the fastening force required for the fuel cell stack 100 and the like. .

  In the above-described embodiment, the end plates 104 and 106 function as output terminals. However, instead of the end plates 104 and 106, another member (for example, the end plate 104) connected to each of the end plates 104 and 106 is used. , 106 and the power generation unit 102) may function as output terminals.

  Further, in the above 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, but even in such a case. Alternatively, the two power generation units 102 may include respective interconnectors 150. In the above-described embodiment, the upper interconnector 150 of the power generation unit 102 located at the top in the fuel cell stack 100 and the lower interconnector 150 below the power generation unit 102 located at the lowest are omitted. These interconnectors 150 may be provided without being omitted.

  Further, in the above embodiment, the fuel electrode side current collector 144 may have the same configuration as the air electrode side current collector 134, and the fuel electrode side current collector 144 and the adjacent interconnector 150 are integrated members. It may be. Further, the fuel electrode side frame 140 instead of the air electrode side frame 130 may be an insulator. Further, the air electrode side frame 130 and the fuel electrode side frame 140 may have a multilayer structure.

  Further, the material forming each member in the above embodiment is merely an example, and each member may be formed of another material.

  In the above embodiment, the city gas is reformed to obtain the hydrogen-rich fuel gas FG. However, the fuel gas FG may be obtained from other raw materials such as LP gas, kerosene, methanol, and gasoline, Pure hydrogen may be used as the fuel gas FG.

  Further, in the above embodiment, a reaction prevention layer formed of, for example, ceria is provided between the electrolyte layer 112 and the air electrode 114, and zirconium and the like in the electrolyte layer 112 react with strontium and the like in the air electrode 114. The increase in electrical resistance between the electrolyte layer 112 and the air electrode 114 due to this may be suppressed.

 In the above embodiments, the solid oxide fuel cell (SOFC) has been described as an example. However, the present invention is not limited to the solid polymer fuel cell (PEFC), the phosphoric acid fuel cell (PAFC), and the molten carbonate fuel cell. The present invention is applicable to other types of fuel cells such as a fuel cell (MCFC).

10: Fuel cell hot module 20: Power generation module 22: Bolt 24: Nut 26: Insulation sheet 27: Gas passage member 28: Main body 29: Branch 30: Heat insulation container 100: Fuel cell stack 102: Power generation unit 104: End plate 105: screw hole 106: end plate 107: screw hole 108: communication hole 109: bolt hole 110: single cell 112: electrolyte layer 114: air electrode 116: fuel electrode 120: separator 121: hole 124: junction 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 145: electrode Direction part 146: Interconnector opposed part 147: Connecting part 149: Spacer 150: Interconnector 161: Oxidant gas introduction manifold 162: Oxidant gas discharge manifold 166: Air chamber 171: Fuel gas introduction manifold 172: Fuel gas discharge manifold 176 : Fuel chamber 200: Auxiliary device 208: Hole 210: Auxiliary device main body 212: Primary combustion chamber 214: Reforming chamber 216: Secondary combustion chamber 218: Flow path 220: Fixed part 221: Screw hole 222: Partition wall 224: Screw Part 226: Shaft 227: Screw 228: Flange 229: Seat 232: Oxidant gas introduction pipe 234: Raw fuel gas introduction pipe 236: Reformed water introduction pipe 238: Exhaust gas discharge pipe 249: Seat

Claims (5)

A plurality of power generation units arranged side by side in the first direction;
A plurality of fastening members each including a shaft extending in the first direction and having a threaded portion formed therein, and a flange located on one side of the shaft in the first direction;
In the fuel cell structure fastened by the plurality of fastening members,
It is arranged on the one side in the first direction with respect to the plurality of power generation units, and directly on a seat surface that is a surface on the other side in the first direction in the flange portion of the plurality of fastening members, or A first member that contacts through another member;
A plurality of screw holes which are arranged on the other side in the first direction with respect to the plurality of power generation units and are formed with a plurality of screw holes screwed into the screw portions formed in the shaft portions of the plurality of fastening members . A second member, wherein an outer peripheral line of the second member includes the plurality of fastening members when viewed in the first direction .
The fastening member is formed of Inconel material,
The first member and the second member are formed of a stainless material,
A fuel cell structure, wherein the plurality of power generation units are formed with a bolt hole through which the shaft portion of the fastening member passes and a communication hole through which gas supplied to the power generation unit passes. . The fuel cell structure according to claim 1,
The fuel cell structure, wherein the shaft portion and the flange portion of the fastening member are an integral member. The fuel cell structure according to claim 1 or 2,
The position of the end of the screw portion on the other side in the first direction in the first direction is compared with the position of the end of the screw hole on the other side in the first direction in the first direction. The same or the other side in the first direction. The fuel cell structure according to any one of claims 1 to 3,
The fuel cell structure is a fuel cell stack including the plurality of power generation units, and the first member and the second member forming an end in the first direction,
The fuel cell structure, wherein the first member and the second member are flat members. The fuel cell structure according to any one of claims 1 to 3,
The fuel cell structure,
A fuel cell stack including the plurality of power generation units,
An auxiliary device having at least one of a combustion chamber for burning gas discharged from the fuel cell stack and a reforming chamber for reforming raw fuel gas to generate a fuel gas to be supplied to the fuel cell stack. When,
A power generation module comprising:
The fuel cell structure, wherein the second member is the auxiliary device.

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