JP2019003795A - Electrochemical reaction unit and electrochemical reaction cell stack - Google Patents

Abstract

To suppress the gas leak in a gas passage owing to the deformation of a separator 120.SOLUTION: An electrochemical reaction unit comprises: a single cell; first and second interconnectors; a separator serving as a partition between gas chambers and having first and second through-holes formed therein, in which a portion surrounding the first through-hole is joined to a peripheral edge of the single cell; a frame member disposed between the separator and the first interconnector, in which third and fourth through-holes for forming the gas chambers are formed; and a glass seal part. When viewed from a first direction, the second through-hole of the separator is larger, in inner diameter, than the fourth through-hole of the frame member; an annular exposed portion exposed from the second through-hole of the separator is present around the fourth through-hole in the frame member. The glass seal part is formed so as to surround a perimeter of the gas passage, and includes a contact portion in contact with the exposed portion of the frame member over its whole perimeter.SELECTED DRAWING: Figure 6

Description

  The technology disclosed herein relates to electrochemical reaction units.

  A solid oxide fuel cell (hereinafter referred to as “SOFC”) is known as one type of fuel cell that generates electricity using an electrochemical reaction between hydrogen and oxygen. The fuel cell power generation unit constituting the SOFC includes, for example, a single cell, a separator, first and second interconnectors, a frame member, and a glass seal portion (see Patent Document 1 below). The single cell includes an electrolyte layer and an air electrode and a fuel electrode facing each other in a predetermined direction (hereinafter referred to as “first direction”) with the electrolyte layer interposed therebetween. The separator is a frame-like member in which a first through hole and a second through hole are formed, and a portion surrounding the first through hole of the separator is joined to a peripheral portion of the single cell. By the separator having such a configuration, an air chamber facing the air electrode and a fuel chamber facing the fuel electrode are partitioned. The first and second interconnectors are flat members arranged so as to face each other in the first direction across the single cell. The frame member is a frame-like member that is disposed between the separator and the first interconnector, and has a third through hole and a fourth through hole that form a fuel chamber. The glass seal portion is disposed between the separator and the second interconnector, and is in contact with both the second interconnector-side surface of the separator and the separator-side surface of the second interconnector to form an air chamber. It has a contact part to seal.

JP2015-156352A

  As described above, in the above conventional technique, the glass seal portion is disposed between the second interconnector and the separator, and is in contact with the second interconnector and the separator. Here, the separator is easily deformed as compared with other members such as a frame member. This is because, for example, the separator is joined to the single cell, and heat generated in the single cell by the electrochemical reaction is directly transferred, so that the deformation amount due to heat is large. In addition, the separator may be formed of a material that is relatively easily deformed in order to reduce stress due to a difference in thermal expansion between the single cell and the frame member. When the separator is deformed, a gap is generated between the separator and the frame member, and the gap between the gas flow path and the gas chamber (air chamber or fuel chamber), or between the gas flow path and the fuel cell power generation unit. There is a risk of gas leakage with the outside.

  Such a problem is common to the structure in which a through-hole forming an air chamber is formed in the frame member and the contact portion of the gas seal member seals the fuel chamber. Such a problem is also common to electrolytic cell units constituting a solid oxide electrolytic cell (hereinafter referred to as “SOEC”) that generates hydrogen using an electrolysis reaction of water. . In this specification, the fuel cell unit cell and the electrolysis cell are collectively referred to as an electrochemical reaction unit cell, and the fuel cell power generation unit and the electrolysis cell unit are collectively referred to as an electrochemical reaction unit.

  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 unit disclosed in the present specification includes a single cell including an electrolyte layer and an air electrode and a fuel electrode facing each other in a first direction with the electrolyte layer interposed therebetween, and the single cell interposed The first and second interconnectors facing each other in the first direction, the first through-hole and the second through-hole are formed, and a portion surrounding the first through-hole is formed in the single cell. A separator that is joined to a peripheral portion and defines an air chamber that faces the air electrode and a fuel chamber that faces the fuel electrode, and is disposed between the separator and the first interconnector; A glass member that includes a glass member that seals between the frame member in which the third through hole constituting the air chamber is formed and the fourth through hole is formed, and the frame member and the second interconnector. And a sealing portion And a gas flow path extending from the first interconnector through the fourth through hole of the frame member and the second through hole of the separator to the second interconnector is formed. In the electrochemical reaction unit, an inner diameter of the second through-hole of the separator is larger than an inner diameter of the fourth through-hole of the frame member in the first direction view, and the first in the frame member An annular exposed portion exposed from the second through hole of the separator exists around the through hole, and the glass seal portion is formed so as to surround the gas flow path; and A contact portion that contacts the exposed portion of the frame member over the entire circumference. According to this electrochemical reaction unit, the glass seal portion is formed so as to surround the gas flow path, and includes a contact portion that contacts the exposed portion of the frame member over the entire circumference. Thereby, compared with the conventional structure which the glass seal part is contacting the separator and is not contacting the frame member, generation | occurrence | production of the gas leak in the gas flow path by the deformation | transformation of a separator can be suppressed.

(2) In the electrochemical reaction unit, the glass seal portion may be separated from the separator over the entire circumference. According to the present electrochemical reaction unit, it is possible to more reliably suppress the occurrence of gas leak in the gas flow path due to the deformation of the separator as compared with the configuration in which the glass seal portion and the separator are in contact with each other.

(3) In the electrochemical reaction cell stack, in the electrochemical reaction cell stack including a plurality of electrochemical reaction units, at least one of the plurality of electrochemical reaction units is the electricity according to claim 1 or 2. It may be a structure characterized by being a chemical reaction unit. According to this electrochemical reaction cell stack, it is possible to suppress the occurrence of gas leak between the gas flow path and the air electrode or the fuel electrode due to the deformation of the separator.

  The technology disclosed in this specification can be realized in various forms. For example, a fuel cell power generation unit, a fuel cell stack including a plurality of fuel cell power generation units, and a power generation module including a fuel cell stack It can be realized in the form of a fuel cell system including a power generation module, an electrolytic cell unit, an electrolytic cell stack including a plurality of electrolytic cell units, a hydrogen generation module including an electrolytic cell stack, a hydrogen generation system including a hydrogen generation module, etc. It is.

1 is a perspective view showing an external configuration of a fuel cell stack 100 in the present embodiment. It is explanatory drawing which shows the XZ cross-section structure of the fuel cell stack 100 in the position of II-II of FIG. 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. 1. It is explanatory drawing which shows XZ cross-section structure of the two electric power generation units 102 adjacent to each other in the same position as the cross section shown in FIG. It is explanatory drawing which shows the YZ cross-section structure of the two electric power generation units 102 adjacent to each other in the same position as the cross section shown in FIG. 4 is an explanatory diagram showing a configuration in the vicinity of a glass seal portion 56 of the fuel cell stack 100. FIG.

A. 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, and FIG. 2 is an explanatory diagram showing an XZ cross-sectional configuration of the fuel cell stack 100 at a position II-II in FIG. FIG. 3 is an explanatory diagram showing a YZ cross-sectional configuration of the fuel cell stack 100 at the position of III-III 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. The same applies to FIG.

  The fuel cell stack 100 includes a plurality (seven in this embodiment) of power generation units 102, a first end plate 104, a second end plate 106, and a current collector plate 18. The seven power generation units 102 are arranged side by side in a predetermined arrangement direction (in this embodiment, the vertical direction (Z-axis direction)). The current collecting plate 18 is disposed below the power generation unit 102 located at the bottom. The first end plate 104 is disposed on the upper side of the uppermost power generation unit 102, and the second end plate 106 is disposed on the lower side of the current collector plate 18. The arrangement direction (vertical direction) corresponds to the first direction in the claims, and the power generation unit 102 corresponds to the electrochemical reaction unit in the claims.

  A plurality of (this embodiment) penetrating in the vertical direction is formed in the peripheral portion around the Z direction of each layer (the power generation unit 102, the first and second end plates 104 and 106, and the current collector plate 18) constituting the fuel cell stack 100. (In the form, eight) holes are formed, and the corresponding holes formed in each layer communicate with each other in the vertical direction, and the through holes 108 extend in the vertical direction from the first end plate 104 to the second end plate 106. Is configured. In the following description, the holes formed in each layer of the fuel cell stack 100 to form the through holes 108 may also be referred to as the through holes 108.

  Bolts 22 extending in the vertical direction are inserted into the through holes 108, and the fuel cell stack 100 is fastened by the bolts 22 and nuts 24 fitted on both sides of the bolts 22.

  The outer diameter of the shaft portion of each bolt 22 is smaller than the inner diameter of each through hole 108. Therefore, a space is secured between the outer peripheral surface of the shaft portion of each bolt 22 and the inner peripheral surface of each through hole 108. As shown in FIGS. 1 and 2, the fuel cell stack 100 is located near the midpoint of one side (the X-axis positive direction side of two sides parallel to the Y-axis) on the outer periphery around the Z-direction. The space formed by the bolt 22 (bolt 22A) and the through-hole 108 into which the bolt 22A is inserted is introduced with the oxidant gas OG from the outside of the fuel cell stack 100, and the oxidant gas OG is generated by each power generation. It functions as an oxidant gas introduction manifold 161 that is a gas flow path to be supplied to the unit 102, and is the midpoint of the side opposite to the side (X-axis negative direction side of two sides parallel to the Y-axis) The space formed by the bolts 22 (bolts 22B) located in the vicinity and the through holes 108 into which the bolts 22B are inserted has an oxidant off-gas OOG that is a gas discharged from the air chamber 166 of each power generation unit 102. Burning Functions as the oxidizing gas discharging manifold 162 for discharging to the outside of the cell stack 100. In the present embodiment, for example, air is used as the oxidant gas OG.

  Further, as shown in FIGS. 1 and 3, the vicinity of 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 of the fuel cell stack 100 around the Z direction The space formed by the bolt 22 (bolt 22D) located at the position and the through hole 108 into which the bolt 22D is inserted is introduced with the fuel gas FG from the outside of the fuel cell stack 100, and the fuel gas FG is generated by each power generation. Bolt 22 that functions as a fuel gas introduction manifold 171 to be supplied to the unit 102 and is located in the vicinity of the midpoint of the opposite side (the side on the Y axis negative direction side of the two sides parallel to the X axis). The space formed by the (bolt 22E) and the through hole 108 into which the bolt 22E is inserted is a fuel cell stack 1 that converts the fuel off-gas FOG, which is a gas discharged from the fuel chamber 176 of each power generation unit 102, into the fuel cell stack 1. Functions as a fuel gas exhaust manifold 172 for discharging to the outside of the 0. In the present embodiment, as the fuel gas FG, for example, hydrogen-rich gas obtained by reforming city gas is used.

  The fuel cell stack 100 is provided with four gas passage members 27. Each gas passage member 27 is made of metal, and 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. Further, as shown in FIG. 2, the hole of the main body portion 28 of the gas passage member 27 disposed at the position of the bolt 22 </ b> A forming the oxidant gas introduction manifold 161 communicates with the oxidant gas introduction manifold 161. The hole of the main body portion 28 of the gas passage member 27 disposed at the position of the bolt 22 </ b> B that forms the oxidant gas discharge manifold 162 communicates with the oxidant gas discharge manifold 162. Further, as shown in FIG. 3, the hole of the main body portion 28 of the gas passage member 27 arranged at the position of the bolt 22D forming the fuel gas introduction manifold 171 communicates with the fuel gas introduction manifold 171 and the fuel gas The hole of the main body portion 28 of the gas passage member 27 disposed at the position of the bolt 22 </ b> E forming the discharge manifold 172 communicates with the fuel gas discharge manifold 172.

  2 and 3, between the nut 24 fitted on one side (upper side) of the bolt 22 and the upper surface of the first end plate 104 constituting the upper end of the fuel cell stack 100, and For example, a glass material is crystallized between the nut 24 fitted on the other side (lower side) of the bolt 22 and the lower surface of the second end plate 106 constituting the lower end of the fuel cell stack 100. The sealed portion 52 is interposed. However, at locations where the gas passage member 27 is provided, seals disposed on the upper and lower sides of the gas passage member 27 and the gas passage member 27 between the nut 24 and the surface of the second end plate 106, respectively. The part 52 is interposed. The seal portion 52 is formed with holes communicating with the through holes 108 and the holes of the main body portion 28 of the gas passage member 27 described above. Two conductive members (for example, the nut 24 and the first end plate 104) that are adjacent to each other in the arrangement direction with the seal portion 52 interposed therebetween are electrically insulated by the seal portion 52, and between the two conductive members. Gas sealing performance is ensured.

(Configuration of end plates 104 and 106)
The first and second end plates 104 and 106 are substantially rectangular flat plate-shaped conductive members, and are made of, for example, stainless steel. The second end plate 106 corresponds to a flat plate-like member in the claims. The first end plate 104 includes a first protrusion 14 that protrudes in a direction substantially orthogonal to the arrangement direction (for example, the X-axis negative direction). The first protrusion 14 of the first end plate 104 functions as a positive output terminal of the fuel cell stack 100.

(Configuration of current collector 18)
The current collecting plate 18 is a substantially rectangular flat plate-shaped conductive member, and is made of, for example, stainless steel. The current collector 18 includes a second protrusion 16 that protrudes in a direction substantially orthogonal to the arrangement direction (for example, the positive direction of the X axis). The protrusion 16 of the current collector 18 functions as a negative output terminal of the fuel cell stack 100.

  Between the current collector plate 18 and the second end plate 106, a seal portion 54 formed by crystallization of a glass material and an insulating material 57 such as mica are interposed. A hole is formed in the insulating material 57 at a position corresponding to each of the through holes 108, and a seal portion 54 is disposed inside the hole. The seal portion 54 is formed with a hole communicating with each through hole 108 described above. The current collector 18 and the second end plate 106, which are two conductive members adjacent to each other in the arrangement direction with the seal 54 interposed therebetween, are electrically insulated by the seal 54, and the current collector 18 Gas sealing performance with the second end plate 106 is ensured.

(Configuration of power generation unit 102)
4 is an explanatory diagram showing an XZ cross-sectional configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. 2, and FIG. 5 is adjacent to each other at the same position as the cross section shown in FIG. It is explanatory drawing which shows the YZ cross-section structure of the two electric power generation units.

  As shown in FIGS. 4 and 5, the power generation unit 102 that is the minimum unit of power generation includes a single cell 110, a separator 120, an air electrode side frame 130, a glass seal portion 56, and an air electrode side current collector 134. A fuel electrode side frame 140, a fuel electrode side current collector 144, and a pair of interconnectors 150 constituting the uppermost layer and the lowermost layer of the power generation unit 102. A hole corresponding to the above-described through hole 108 into which the bolt 22 is inserted is formed in a peripheral portion around the Z direction in the fuel electrode side frame 140 and the interconnector 150.

  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. Therefore, a certain interconnector 150 faces an air chamber 166 facing an air electrode 114 (described later) in a power generation unit 102, and a fuel electrode 116 (described later) in another power generation unit 102 adjacent to the upper side of the power generation unit 102. Facing the fuel chamber 176 facing the front. In addition, since the fuel cell stack 100 includes the first end plate 104 and the current collector plate 18, the power generation unit 102 located at the top of the fuel cell stack 100 does not include the upper interconnector 150. The power generation unit 102 located below does not include the lower interconnector 150 (see FIGS. 2 and 3). The lower interconnector 150 corresponds to the first interconnector in the claims, and the upper interconnector 150 corresponds to the second interconnector in the claims.

  The unit cell 110 includes an electrolyte layer 112 and an air electrode 114 and a fuel electrode 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 rectangular flat plate-like member, such as YSZ (yttria stabilized zirconia), ScSZ (scandia stabilized zirconia), SDC (samarium doped ceria), GDC (gadolinium doped ceria), perovskite oxide, etc. The solid oxide is formed. The air electrode 114 is a 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)). ing. The fuel electrode 116 is a 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 made of the same material as that of the fuel electrode side frame 140, for example. The separator 120 is bonded to the electrolyte layer 112 (single cell 110) by a bonding portion 124 formed of a brazing material (for example, Ag 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 single cell 110 to which the separator 120 is bonded is also referred to as a single cell with a separator. Furthermore, the separator 120 is formed with a hole 120A that penetrates the separator 120 in the vertical direction at a position corresponding to each through hole 108 described above. The inner diameter of the hole 120A is larger than the inner diameter of the through hole 108. The hole 121 described above corresponds to the first through hole in the claims, and the hole 120A corresponds to the second through hole in the claims.

  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 edge portion of the surface of the separator 120 opposite to the side facing the electrolyte layer 112 and the peripheral edge portion of the surface of the interconnector 150 facing the air electrode 114. . That is, the air electrode side frame 130 is sandwiched between the separator 120 and the interconnector 150. Therefore, the air electrode side frame 130 realizes a seal (compression seal) for the air chamber 166. The pair of interconnectors 150 included in the power generation unit 102 is electrically insulated by the air electrode side frame 130. The air electrode side frame 130 has an oxidant gas supply communication hole 132 communicating the oxidant gas introduction manifold 161 and the air chamber 166, and an oxidant gas communicating the air chamber 166 and the oxidant gas discharge manifold 162. A discharge communication hole 133 is formed. Further, the air electrode side frame 130 is formed with holes 130A that penetrate the air electrode side frame 130 in the vertical direction at positions corresponding to the through holes 108. The inner diameter of the hole 130A is larger than the inner diameter of the through hole 108.

  A glass seal portion 56 is disposed inside each hole 130 </ b> A in the air electrode side frame 130. The glass seal portion 56 is formed by crystallizing a glass material. The configuration in the vicinity of the glass seal portion 56 (glass seal portion 56, air electrode side frame 130, separator 120) will be described later.

  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 electrolyte layer 112 and the peripheral portion of the surface of the interconnector 150 facing the fuel electrode 116. Further, the fuel electrode side frame 140 has a fuel gas supply communication hole 142 that connects the fuel gas introduction manifold 171 and the fuel chamber 176, and a fuel gas discharge communication hole 143 that connects the fuel chamber 176 and the fuel gas discharge manifold 172. And are formed. The fuel electrode side frame 140 corresponds to a frame member in the claims, the hole 141 corresponds to a third through hole in the claims, and the through hole 108 formed in the fuel electrode side frame 140 includes: This corresponds to the fourth through hole in the claims.

  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, an electrode facing portion 145, and a connecting portion 147 that connects the electrode facing portion 145 and the interconnector facing portion 146. For example, nickel or a nickel alloy It is made of stainless steel or the like. The electrode facing portion 145 is in contact with the surface of the fuel electrode 116 on the side opposite to the side facing the electrolyte layer 112, and the interconnector facing portion 146 is on the surface of the interconnector 150 on the side facing the fuel electrode 116. In contact. However, as described above, the lowermost power generation unit 102 in the fuel cell stack 100 does not include the lower interconnector 150, and therefore the interconnector facing portion 146 in the power generation unit 102 has the current collecting plate 18. Touching the surface. Since the fuel electrode side current collector 144 has such a configuration, the fuel electrode 116 and the interconnector 150 (or the current collector plate 18) are electrically connected. Note that a spacer 149 made of, for example, mica is disposed between the electrode facing portion 145 and the interconnector facing portion 146. Therefore, the fuel electrode side current collector 144 follows the deformation of the power generation unit 102 due to the temperature cycle or reaction gas pressure fluctuation, and the fuel electrode 116 and the interconnector 150 are electrically connected via the fuel electrode side current collector 144. Maintained well.

  The air electrode side current collector 134 is disposed in the air chamber 166. The air electrode side current collector 134 is composed of a plurality of current collector elements 135 having a substantially quadrangular prism shape, and is formed 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 in the uppermost position in the fuel cell stack 100 does not include the upper interconnector 150, the air electrode side current collector 134 of the power generation unit 102 has the first end. It is in contact with the surface of the plate 104. Thus, the air electrode side current collector 134 electrically connects the air electrode 114 and the interconnector 150 (or the first end plate 104). The air electrode side current collector 134 and the interconnector 150 may be formed as an integral member.

A-2. Operation of the fuel cell stack 100:
As shown in FIGS. 2 and 4, the oxidant gas OG is supplied through a gas pipe (not shown) connected to the branch portion 29 of the gas passage member 27 provided at the position of the oxidant gas introduction manifold 161. Then, the oxidant gas OG is supplied to the oxidant gas introduction manifold 161 through the branch portion 29 of the gas passage member 27 and the hole of the main body portion 28, 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 FIGS. 3 and 5, the fuel gas FG is supplied through a gas pipe (not shown) connected to the branch portion 29 of the gas passage member 27 provided at the position of the fuel gas introduction manifold 171. Then, the fuel gas FG is supplied to the fuel gas introduction manifold 171 through the branch portion 29 of the gas passage member 27 and the hole of the main body portion 28, and the fuel gas supply communication of each power generation unit 102 from the fuel gas introduction manifold 171. The fuel chamber 176 is supplied through the hole 142.

  When the oxidant gas OG is supplied to the air chamber 166 of each power generation unit 102 and the fuel gas FG is supplied to the fuel chamber 176, power is generated by an electrochemical reaction between the oxidant gas OG and the fuel gas FG in the single cell 110. Is called. 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 via the air electrode side current collector 134, and the fuel electrode 116 is connected via the fuel electrode side current collector 144. The other interconnector 150 is electrically connected. 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 taken out from the first protrusion 14 of the first end plate 104 that functions as an output terminal and the second protrusion 16 of the current collector plate 18. 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 start-up until the high temperature can be maintained by the heat generated by the power generation. (Not shown).

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

A-3. Arrangement near the glass seal 56:
FIG. 6 is an explanatory diagram showing a configuration in the vicinity of the glass seal portion 56 of the fuel cell stack 100. The upper part of FIG. 6 shows an XZ sectional configuration of the X1 portion of the power generation unit 102 in FIG. 5 in an enlarged manner, and the lower part of FIG. 6 shows the power generation unit at the position X2-X2 in the upper part of FIG. The XY cross-sectional configuration of the X1 portion of 102 is shown enlarged. FIG. 6 shows a glass seal 56 formed so as to surround the periphery of the fuel gas discharge manifold 172.

  As shown in FIG. 6, the inner diameter of the hole 120A formed in the separator 120 is larger than the inner diameter of the through-hole 108 formed in the fuel electrode side frame 140 and the interconnector 150, and viewed in the vertical direction (Z direction). The hole 120A is located outside the through hole 108 over the entire circumference. Therefore, an annular exposed portion 140 </ b> A exposed from the hole 120 </ b> A formed in the separator 120 exists around the through hole 108 on the upper surface of the fuel electrode side frame 140. Further, the inner diameter of the hole 130A formed in the air electrode side frame 130 is larger than the inner diameter of the through hole 108 formed in the fuel electrode side frame 140 and the interconnector 150, and the hole is viewed in the vertical direction (Z direction). 130A is located outside the through hole 108 over the entire circumference. Therefore, the separator 120 and the air electrode side frame 130 do not exist between the exposed portion 140A of the fuel electrode side frame 140 and the upper interconnector 150 in the vertical direction. In FIG. 6, the inner diameter of the hole 120A and the inner diameter of the hole 130A are substantially the same, but the inner diameter of the hole 120A may be larger than the inner diameter of the hole 130A, or the inner diameter of the hole 120A is smaller than the inner diameter of the hole 130A. May be.

  The glass seal portion 56 is located inside each hole 130A in the air electrode side frame 130 and each hole 120A formed in the separator 120, and is disposed so as to surround each manifold 161, 162, 171, 172. . Specifically, the glass seal portion 56 has a substantially cylindrical shape in which a hole 56A penetrating in the vertical direction is formed. The upper end surface of the glass seal portion 56 is in contact with the peripheral portion of the through hole 108 on the lower surface of the upper interconnector 150, and the lower end surface of the glass seal portion 56 penetrates the upper surface of the fuel electrode side frame 140. The peripheral portion of the hole 108 (exposed portion 140A) is in contact with the entire circumference. The glass seal portion 56 electrically insulates the fuel electrode side frame 140 and the upper interconnector 150 which are two conductive members adjacent to each other in the arrangement direction with the glass seal portion 56 interposed therebetween, and the fuel electrode side. A gas sealing property between the frame 140 and the upper interconnector 150 is ensured. The glass seal portion 56 corresponds to the glass seal portion in the claims, and the lower end surface of the glass seal portion 56 corresponds to the contact portion in the claims.

  The inner diameter of the hole 120A formed in the separator 120 is larger than the outer diameter of the glass seal portion 56, and the separator 120 and the glass seal portion 56 are separated from each other over the entire circumference. The inner diameter of the hole 130A formed in the air electrode side frame 130 is also larger than the outer diameter of the glass seal portion 56, and the air electrode side frame 130 and the glass seal portion 56 are separated from each other over the entire circumference.

  On the other hand, as described above, the air electrode side frame 130 located on the outer peripheral side of the glass seal portion 56 is sandwiched between the separator 120 and the interconnector 150 over the entire periphery. The air electrode side frame 130 ensures a seal between the air electrode side frame 130 and the separator 120 and a seal between the separator 120 and the fuel electrode side frame 140. That is, the air electrode side frame 130 ensures the gas sealing property between the air chamber 166 and the fuel chamber 176. In the fuel cell stack 100 of this embodiment, a welded portion 410 that seals between the fuel electrode side frame 140 and the separator 120 is formed (see the upper diagram in FIG. 6). The welding part 410 is formed by laser welding, for example. The welded portion 410 is continuously formed so as to surround the hole 120A formed in the separator 120 when viewed in the vertical direction. The welded portion 410 ensures the gas sealing property between the air chamber 166 and the fuel chamber 176 more reliably.

A-4. Effects of this embodiment:
As described above, in the fuel cell stack 100 of the present embodiment, the glass seal portion 56 includes gas flow paths (oxidant gas introduction manifold 161, oxidant gas discharge manifold 162, fuel gas introduction manifold 171, fuel gas discharge manifold 172. ) And a contact portion that contacts the exposed portion 140A of the fuel electrode side frame 140 without going through the separator 120 over the entire circumference. Thereby, for example, compared with a configuration in which the glass seal portion 56 is in contact with the separator 120 and is not in contact with the fuel electrode side frame 140, generation of gas leak in the gas flow path due to deformation of the separator 120 can be suppressed. it can.

  Specifically, for example, in the configuration shown in FIG. 6, it is assumed that the inner diameter of the hole 120 </ b> A formed in the separator 120 and the inner diameter of the through hole 108 formed in the fuel electrode side frame 140 are substantially the same. In the configuration in which 56 is sandwiched between the separator 120 and the upper interconnector 150, the following problem may occur. For example, the separator 120 is more easily deformed than other members such as the fuel electrode side frame 140. The reason is that, for example, the separator 120 is joined to the single cell 110 arranged so as to float between the air chamber 166 and the fuel chamber 176, and the surface of the air electrode 114 of the single cell 110 and the fuel electrode 116. Although the air electrode side current collector 134 and the fuel electrode side current collector 144 are partially in contact with each other, the heat generated in the single cell 110 due to the electrochemical reaction is directly transferred. This is because the amount of deformation due to heat is large. In addition, the separator 120 may be formed of a material that is relatively easily deformed in order to reduce stress due to a difference in thermal expansion between the single cell 110 and the fuel electrode side frame 140. In addition, 120 may be somewhat distorted by heat treatment in the manufacturing process.

  When the separator 120 is deformed, a gap is generated between the separator 120 and the fuel electrode side frame 140, and the gap between the fuel gas discharge manifold 172 and the air chamber 166 or the fuel gas discharge manifold 172 and the fuel cell is formed through the gap. There is a possibility that a gas leak of the fuel off-gas FOG may occur between the outside of the stack 100 (atmosphere). On the other hand, as described above, in the fuel cell stack 100 of the present embodiment, the glass seal portion 56 is formed so as to surround the fuel gas discharge manifold 172, and the exposed portion of the fuel electrode side frame 140 is exposed. A contact portion that contacts the entire circumference without passing through the separator 120 is included with respect to 140A. Therefore, the occurrence of gas leak in the fuel gas discharge manifold 172 can be suppressed without being affected by the difference in thermal expansion between the separator 120 and the fuel electrode side frame 140.

  In the present embodiment, the inner diameter of the hole 120A formed in the separator 120 is larger than the outer diameter of the glass seal portion 56, and the separator 120 and the glass seal portion 56 are separated from each other over the entire circumference. Even if the separator 120 is deformed, the state in which the glass seal portion 56 is sandwiched between the upper interconnector 150 and the fuel electrode side frame 140 is maintained. Therefore, compared with the configuration in which the glass seal portion 56 and the separator 120 are in contact with each other, the occurrence of gas leak in the gas flow path due to the deformation of the separator 120 can be more reliably suppressed.

B. Variation:
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.

  In the above embodiment, all four glass seal portions 56 formed so as to surround the four manifolds 161, 162, 171, and 172, respectively, with respect to the exposed portion 140 </ b> A of the fuel electrode side frame 140 over the entire circumference. However, instead of this, for example, only the part of the four glass seal portions 56 may include the contact portion. For example, only the two glass seal portions 56 that respectively surround the fuel gas introduction manifold 171 and the fuel gas discharge manifold 172 that require particularly high gas leakage properties include the contact portions, and the oxidant gas introduction manifold 161 and the oxidant gas discharge. The two glass seal portions 56 that respectively surround the manifold 162 may be sandwiched between the separator 120 and the upper interconnector 150 without including the contact portion.

  In the said embodiment, although the separator 120 and the glass seal part 56 were spaced apart over the perimeter, if the separator 120 contains the said contact part, the separator 120 and the glass seal part 56 will be a perimeter or It may be in contact with a part. Moreover, as long as the separator 120 includes the contact portion, a part of the separator 120 may overlap the glass seal portion 56 as viewed in the vertical direction. For example, the inner diameter of the hole 120A of the separator 120 is larger than the inner diameter of the glass seal portion 56 and smaller than the outer diameter of the glass seal portion 56, and the inner peripheral side of the glass seal portion 56 is the fuel electrode side frame 140 and the upper interconnector. 150, and the outer peripheral side of the glass seal portion 56 may be sandwiched between the separator 120 and the upper interconnector 150. With such a configuration, the glass seal portion 56 can ensure the gas sealability between the air chamber 166 and the fuel chamber 176 in addition to the gas sealability in the gas flow path.

  In the above embodiment, the air electrode side frame 130 and the glass seal portion 56 are separated from each other over the entire circumference. However, the air electrode side frame 130 and the glass seal portion 56 are in contact with each other over the entire circumference or a part thereof. It may be. When the air electrode side frame 130 contacts the glass seal portion 56, for example, the strength of the glass seal portion 56 can be reinforced. Further, the inner diameter of the hole 130A of the air electrode side frame 130 may be smaller than the inner diameter of the hole 120A of the separator 120. With such a configuration, the contact between the separator 120 and the glass seal portion 56 can be suppressed.

  In the above embodiment, both the compression seal by the air electrode side frame 130 and the welded portion 410 are formed in order to ensure the gas sealability between the air chamber 166 and the fuel chamber 176. Either one of the compression seal and the welded portion 410 may be formed.

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

  Moreover, in the said embodiment, although the space between the outer peripheral surface of the axial part of each bolt 22 and the inner peripheral surface of each through-hole 108 is utilized as each manifold, it replaces with this and the axis | shaft of each bolt 22 is used. An axial hole may be formed in the part, and the hole may be used as each manifold. Further, each manifold may be provided separately from each through hole 108 into which each bolt 22 is inserted.

  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. Two power generation units 102 may be provided with respective interconnectors 150. In the above embodiment, the upper interconnector 150 of the uppermost power generation unit 102 in the fuel cell stack 100 and the lower interconnector 150 of the lowermost power generation unit 102 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 an integral member. It may be. Further, the fuel electrode side frame 140 instead of the air electrode side frame 130 may be an insulator. The air electrode side frame 130 and the fuel electrode side frame 140 may have a multilayer structure.

  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.

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

  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 the member 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, even in a configuration in which another layer is provided between the electrolyte layer 112 and the air electrode 114, 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 cell unit 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 cell units. The configuration of the electrolytic cell stack is well known as described in, for example, Japanese Patent Application Laid-Open No. 2006-81813, and thus will not be described in detail here. It is a configuration. That is, the fuel cell stack 100 in the above-described embodiment may be read as an electrolytic cell stack, the power generation unit 102 may be read as an electrolytic cell unit, and the single cell 110 may be read as an electrolytic single cell. However, when the electrolysis cell stack is operated, a voltage is applied between the two electrodes so that the air electrode 114 is positive (anode) and the fuel electrode 116 is negative (cathode), and through the through hole 108. Water vapor as a source gas is supplied. 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 through hole 108. Also in the electrolytic cell unit and the electrolytic cell stack having such a configuration, the glass seal portion is formed so as to surround the gas flow path, and the entire periphery of the exposed portion of the frame member, as in the above embodiment. If the contact portion is included, the occurrence of gas leak in the gas flow path due to the deformation of the separator can be suppressed.

14: 1st protrusion part 16: 2nd protrusion part 18: Current collector plate 22: Bolt 24: Nut 27: Gas passage member 28: Main body part 29: Branch part 52, 54: Seal part 56: Glass seal part 56A : Hole 57: Insulating material 100: Fuel cell stack 102: Power generation unit 104, 106: End plate 108: Through hole 110: Single cell 112: Electrolyte layer 114: Air electrode 116: Fuel electrode 120: Separator 120A, 121: Hole 124 : Junction 130: Air electrode side frame 130A, 131: Hole 132: Oxidant gas supply communication hole 133: Oxidant gas discharge communication hole 134: Air electrode side current collector 135: Current collector element 140: Fuel electrode side frame 140A: Exposed portion 141: Hole 142: Fuel gas supply communication hole 143: Fuel gas discharge communication hole 144 Fuel electrode side current collector 145: Electrode facing portion 146: Interconnector facing portion 147: Connection portion 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 410: Welded part FG: Fuel gas FOG: Fuel off gas OG: Oxidant gas OOG: Oxidant off gas

Claims (3)

A single cell including an electrolyte layer and an air electrode and a fuel electrode facing each other in a first direction across the electrolyte layer;
First and second interconnectors facing each other in the first direction across the single cell;
A first through hole and a second through hole are formed, and a portion surrounding the first through hole is joined to a peripheral portion of the single cell, and faces the air chamber facing the air electrode and the fuel electrode. A separator that partitions the fuel chamber
A frame member that is disposed between the separator and the first interconnector, and has a third through hole that forms the fuel chamber or the air chamber and a fourth through hole;
Sealing between the frame member and the second interconnector, and comprising a glass seal portion containing glass,
An electrochemical system in which a gas flow path extending from the first interconnector through the fourth through hole of the frame member and the second through hole of the separator to the second interconnector is formed. In reaction units,
In the first direction view, the inner diameter of the second through hole of the separator is larger than the inner diameter of the fourth through hole of the frame member, and the periphery of the fourth through hole in the frame member Has an annular exposed portion exposed from the second through hole of the separator,
The said glass seal part is formed so that the circumference | surroundings of the said gas flow path may be enclosed, and the contact part which contacts the said exposed part of the said frame member over a perimeter is characterized by the above-mentioned. The electrochemical reaction unit according to claim 1,
The electrochemical reaction unit, wherein the glass seal portion is spaced from the separator over the entire circumference. In an electrochemical reaction cell stack comprising a plurality of electrochemical reaction units,
The electrochemical reaction cell stack according to claim 1, wherein at least one of the plurality of electrochemical reaction units is the electrochemical reaction unit according to claim 1.

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