JP6659770B2 - Fuel cell stack - Google Patents

Description

  The present invention provides a laminate in which a plurality of power generation cells each having an electrolyte membrane / electrode structure, a resin frame member surrounding the outer periphery of the electrolyte membrane / electrode structure, and a separator, and at least one of the lamination directions of the laminate are provided. The present invention relates to a fuel cell stack including a dummy cell disposed at an end of the fuel cell stack.

  In general, a solid polymer fuel cell employs a solid polymer electrolyte membrane (hereinafter, also simply referred to as an electrolyte membrane) composed of a polymer ion exchange membrane. A fuel cell includes an electrolyte membrane-electrode structure (MEA) in which an anode electrode is provided on one surface of an electrolyte membrane and a cathode electrode is provided on the other surface.

  A power generation cell is configured by sandwiching the electrolyte membrane / electrode structure with a separator, and a stacked body is configured by stacking a plurality of power generation cells. At both ends in the stacking direction of the stack, a terminal plate for power extraction for collecting electric charges generated by each power generation cell, an end plate for holding the power generation cells in a stacked state, and the like are provided to form a fuel cell stack. You.

  By the way, the end of the laminate in the laminating direction (hereinafter, also simply referred to as the end) has a lower temperature than the center in the laminating direction of the laminate because heat is radiated through terminal plates and the like. easy. When the temperature of the end portion of the stacked body becomes low due to the influence of the outside air temperature and the dew condensation occurs, there is a concern that the diffusibility of the reaction gas decreases and the power generation stability of the fuel cell stack decreases.

  Therefore, for example, in the fuel cell stack disclosed in Patent Literature 1, a so-called dummy cell is disposed on at least one end side in the stacking direction of the stack. In the dummy cell, since a metal plate is used instead of the electrolyte membrane, no power is generated and no generated water is generated. For this reason, the dummy cell itself functions as a heat insulating layer between the terminal plate and the stacked body. Therefore, by arranging the dummy cells as described above, it is possible to suppress a temperature drop on the end side of the stacked body. That is, it is possible to suppress the influence of the outside air temperature on the fuel cell stack and improve the power generation stability.

Japanese Patent No. 4727772

  The present invention has been made in connection with this type of technology, and has as its object to provide a fuel cell stack capable of improving power generation stability by using dummy cells in which freezing is suppressed.

  In order to achieve the above object, the present invention provides an electrolyte membrane / electrode structure in which electrodes each having a gas diffusion layer made of a conductive porous material are provided on both sides of an electrolyte membrane, and an electrolyte membrane / electrode structure A laminate formed by stacking a plurality of power generation cells each having a resin frame member orbiting the outer periphery of the battery and a separator sandwiching the electrolyte membrane / electrode structure, and a dummy cell disposed at at least one end in the stacking direction of the laminate. A fuel cell stack comprising: a dummy cell comprising: a dummy structure corresponding to the electrolyte membrane / electrode structure; a dummy resin frame member surrounding the outer periphery of the dummy structure; and a dummy separator sandwiching the dummy structure. The dummy structure is formed by laminating three conductive porous bodies having different plane dimensions, and each of the separator and the dummy separator is oxidized in the laminating direction of the laminate. An oxidizing gas communication hole for flowing gas and a fuel gas communication hole for flowing fuel gas in the stacking direction of the laminate are formed, and the separator facing the one electrode of the electrolyte membrane / electrode structure has an oxidizing agent. An oxidizing gas flow path through which a gas flows is provided, and a fuel gas flow path through which a fuel gas flows is provided in a separator facing the other electrode of the electrolyte membrane / electrode structure, and a fuel gas flow path in the stacking direction of the dummy structure is provided. A first space corresponding to the oxidant gas flow path is provided between the dummy separator facing one end and one end of the dummy structure, and the dummy separator faces the other end of the dummy structure in the stacking direction. A second space corresponding to the fuel gas flow path is provided between the fuel cell and the other end of the dummy structure, and an oxidant gas can flow between the oxidant gas communication hole and the first space. Communication passage, and a dummy structure To the first space and the second space, wherein the through-hole communicating with a vertically lower part is provided.

  In this fuel cell stack, a dummy cell having a dummy structure is provided at at least one end in the stacking direction of the stack, instead of the electrolyte membrane / electrode structure of the power generation cell. Since the dummy cell is not provided with the solid polymer electrolyte membrane or the electrode catalyst layer, it does not generate power and does not generate water generated by power generation. Thereby, the dummy cell itself functions as a heat insulating layer, and the occurrence of condensation in the dummy cell can be suppressed. By providing the dummy cells on at least one end side in the stacking direction of the stacked body as described above, the heat insulating property on the end side of the stacked body can be improved. For this reason, even in a low-temperature environment, it is possible to suppress the temperature at the end portion side of the laminate from becoming lower than that at the center side. That is, power generation stability can be improved.

  In addition, since the heat insulating property at the end of the stack can be improved, the entire stack can be effectively heated even when the fuel cell stack is started in a sub-zero environment. Thereby, it is possible to prevent the generated water or the like from freezing on the end side of the laminated body, thereby preventing a voltage drop.

  A humidified oxidant gas is supplied to the inlet side of the oxidant gas communication hole of the fuel cell stack. When the water in the oxidizing gas condenses, liquid condensed water is generated, and when the condensed water jumps into the power generation cell, the diffusibility of the reaction gas may decrease. Therefore, in this fuel cell stack, the oxidant gas communication hole and the first space facing one end of the dummy structure in the stacking direction are communicated via the communication passage. This allows the oxidant gas to flow through the first space, so that even if the oxidant gas contains dew water, the dew water is collected by the dummy cell and condensed on the power generation cell. It can suppress that water jumps in.

  The liquid water such as dew condensation collected by the dummy cell is used when the flow rate of the oxidizing gas flowing through the first space is increased during the high-load power generation of the fuel cell stack, or during the drying process while the fuel cell stack is stopped, or When is dried, the discharge from the dummy cell is prompted. Since the dummy structure is provided with a through-hole that connects the first space and the second space at the lower part in the vertical direction, even if the liquid water enters the second space, the liquid water is not affected by gravity. , And is guided to the first space side through the through hole.

  As a result, the oxidizing gas flowing through the first space can further promote the drainage from the dummy cell, and can suppress the liquid water from staying inside the dummy cell. Can be prevented from freezing. Therefore, according to this fuel cell stack, the power generation stability can be improved by the dummy cells in which freezing is suppressed.

  In the above fuel cell stack, it is preferable that the through hole of the dummy structure is provided near the oxidizing gas communication hole on the outlet side of the oxidizing gas flowing through the first space. In this case, the liquid water guided from the second space to the first space via the through hole can be effectively discharged to the outside of the dummy cell (the oxidant gas communication hole on the outlet side).

  In the above fuel cell stack, the separator and the dummy separator have a rectangular shape whose longitudinal direction extends along the horizontal direction, and the oxidant gas flow path and the oxidant gas are supplied to the first space in the vertically upper part of the separator and the dummy separator. An inlet-side oxidizing gas communication hole is provided, and an outlet-side oxidizing gas communication hole through which the oxidizing gas is discharged from the oxidizing gas passage and the first space is provided vertically below the separator and the dummy separator. Is preferably provided. In this case, the liquid water in the dummy cell can be effectively guided to the oxidant gas communication hole on the outlet side by gravity, and drained well.

  In the above-described fuel cell stack, it is preferable that the first space allows the oxidant gas to flow in one direction along the longitudinal direction of the dummy separator. In this case, the liquid water in the dummy cell can be easily led to the oxidizing gas communication hole on the outlet side through the first space and drained.

  In the above-described fuel cell stack, it is preferable that a shut-off portion for shutting off the flow of the fuel gas is provided between the fuel gas communication hole and the second space. In this case, the second space, whose heat insulating property is enhanced by the non-flow of the fuel gas, functions as a heat insulating space, so that the heat insulating property of the dummy cell can be further improved. Further, fuel gas discharged from the fuel cell stack without contributing to the electrochemical reaction for power generation can be reduced.

  In the above fuel cell stack, the three conductive porous bodies are a first conductive porous body, a second conductive porous body having a larger planar dimension than the first conductive porous body, and a second conductive porous body. A third conductive porous body having a larger planar dimension than the conductive porous body, wherein the dummy resin frame member is entirely formed from the outer peripheral edge portion and the inner peripheral end of the outer peripheral edge portion via the first step surface; A third conductive porous member having a shelf protruding inward over the circumference, and a thin portion protruding inward over the entire circumference from the inner peripheral end of the shelf via the second step surface; The outer peripheral edge of the body overlaps the shelf of the dummy resin frame member, the outer peripheral edge of the second conductive porous body faces the thin portion of the dummy resin frame member, and the outer peripheral end face of the first conductive porous body. Preferably face the inner peripheral end surface of the dummy resin frame member.

  In the above fuel cell stack, it is preferable that the thickness of the second conductive porous body is larger than the height of the second step surface.

  In the above fuel cell stack, it is preferable that a space is formed between the thin portion of the dummy resin frame member and the third conductive porous body.

  According to the present invention, the power generation stability of the fuel cell stack can be improved by the dummy cells in which freezing is suppressed.

FIG. 1 is an exploded perspective view of a fuel cell stack according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line II-II of the fuel cell stack of FIG. 1. It is an exploded perspective view of a power generation cell. FIG. 3 is a front view of the first separator on the oxidant gas flow path side. It is a front view of the oxidant gas flow path side of the 2nd separator. It is a front view of the cooling medium channel side of the 3rd separator. It is a front view on the anode electrode side of MEA with a resin frame. FIG. 8 is a sectional view taken along line VIII-VIII in FIG. 7. It is a front view on the 3rd conductive porous body side of the dummy structure with a resin frame. FIG. 10 is a sectional view taken along line XX of FIG. 9. It is an exploded perspective view of a dummy structure. It is a front view of the 2nd space side of a dummy 2nd separator and a dummy 3rd separator.

  Preferred embodiments of a fuel cell stack according to the present invention will be described in detail with reference to the accompanying drawings. In the following drawings, components having the same or similar functions and effects are denoted by the same reference numerals, and repeated description may be omitted.

  As shown in FIGS. 1 and 2, the fuel cell stack 10 according to the present embodiment includes a stacked body 14 in which a plurality of power generation cells 12 are stacked in a horizontal direction (directions of arrows A1 and A2). The fuel cell stack 10 is mounted on a fuel cell vehicle such as a fuel cell electric vehicle (not shown), for example.

  As shown in FIG. 2, the first end power generation unit 16, the first dummy cell 18, and the second dummy cell 20 are arranged outward on one end side (the arrow A1 side) in the stacking direction of the stacked body 14. Further, the second end power generation unit 22 and the third dummy cell 24 are disposed outward on the other end side (the arrow A2 side) in the stacking direction of the stack 14. A terminal plate 26a, an insulator 28a, and an end plate 30a are stacked in this order on the outer side (the arrow A1 side) of the second dummy cell 20 of the stacked body 14 in this order. A terminal plate 26b, an insulator 28b, and an end plate 30b are stacked in this order on the outer side (the arrow A2 side) of the third dummy cell 24 of the stacked body 14 in this order.

  As shown in FIG. 1, a connection bar (not shown) is arranged between each side of the rectangular end plates 30a and 30b. Both ends of each connection bar are fixed to the inner surfaces of the end plates 30a and 30b via bolts (not shown) or the like, and apply a tightening load to the plurality of stacked power generation cells 12 in the stacking direction (arrow A1, A2 directions). I do. The fuel cell stack 10 may include a housing having the end plates 30a and 30b as end plates, and the stack 14 and the like may be housed in the housing.

  As shown in FIG. 3, the power generation cell 12 is configured by stacking a first separator 32, a MEA 34 with a resin frame, a second separator 36, a MEA 34 with a resin frame, and a third separator 38 in this order. . Each of the first separator 32, the second separator 36, and the third separator 38 (each separator) is made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, etc., and has a rectangular flat surface and a press work. Thus, the cross section is formed into an uneven shape.

  As shown in FIG. 1 and FIG. 3, the edges on one end side (arrow B1 side) in the long side direction (horizontal direction, arrows B1 and B2 directions) of each separator are in the directions of arrows A1 and A2 (stacking direction), respectively. And an oxidizing gas inlet communication hole 40 (oxidizing gas communication hole) and a fuel gas outlet communication hole 42 (fuel gas communication hole). The oxidizing gas inlet communication hole 40 supplies an oxidizing gas, for example, an oxygen-containing gas. The fuel gas outlet communication hole 42 discharges a fuel gas, for example, a hydrogen-containing gas. These oxidizing gas and fuel gas are collectively referred to as reaction gas.

  At the edge on the other end side (arrow B2 side) in the long side direction of each separator, a fuel gas inlet communication hole 44 (fuel gas communication hole) that individually communicates in the directions of arrows A1 and A2 to supply fuel gas. ) And an oxidizing gas outlet communication hole 46 (oxidizing gas communication hole) for discharging the oxidizing gas. The oxidant gas inlet communication hole 40, the fuel gas outlet communication hole 42, the fuel gas inlet communication hole 44, and the oxidant gas outlet communication hole 46 are collectively referred to as a reaction gas communication hole.

  An oxidant gas inlet communication hole 40 and a fuel gas inlet communication hole 44 are provided in a vertical upper portion (arrow C1 side) of each separator, and a fuel gas outlet communication hole 42 and an oxidizer gas are provided in a vertical lower portion (arrow C2 side). A gas outlet communication hole 46 is provided. The vertical direction here is the vertical direction when operating the fuel cell stack 10.

  A pair of cooling medium inlets for supplying a cooling medium, which are individually communicated in the directions of arrows A1 and A2, on the arrow B1 side of both ends in the short side direction (vertical direction, arrows C1 and C2 directions) of each separator. Each of the communication holes 48 is provided. A pair of cooling medium outlet communication holes 50 for discharging the cooling medium, which are individually communicated in the directions of the arrows A1 and A2, respectively, are provided on both ends of the separator in the short side direction on the arrow B2 side.

  As shown in FIG. 3, a cooling medium flow path 52 that connects the cooling medium inlet communication hole 48 and the cooling medium outlet communication hole 50 is formed on the surface 32 a on the arrow A1 side of the first separator 32. A plurality of inlet connection grooves 54a are formed between the cooling medium inlet communication hole 48 and the cooling medium passage 52. A plurality of outlet connection grooves 54b are formed between the cooling medium flow path 52 and the cooling medium outlet communication holes 50. Further, the surface 32a of the first separator 32 integrally surrounds the cooling medium inlet communication hole 48, the cooling medium outlet communication hole 50, the cooling medium flow path 52, the inlet connection groove 54a, and the outlet connection groove 54b. A seal member 55 for sealing with the outside in the surface direction is provided.

  As shown in FIG. 4, an oxidizing gas flow path 56 communicating with the oxidizing gas inlet communication hole 40 and the oxidizing gas outlet communication hole 46 is formed on the surface 32 b on the arrow A2 side of the first separator 32. . The oxidizing gas channel 56 includes a plurality of wavy flow channels (or straight flow channels) that are parallel to each other.

  An oxidizing gas inlet buffer portion 58 located outside the power generation region is connected to the inlet end of the oxidizing gas flow passage 56, while an outlet end of the oxidizing gas flow passage 56 is connected to the outside of the power generating region. And the oxidizing gas outlet buffer unit 60 is connected.

  A plurality of inlet connection grooves 62a are formed between the oxidant gas inlet buffer 58 and the oxidant gas inlet communication hole 40. A plurality of outlet connection grooves 62b are formed between the oxidant gas outlet buffer portion 60 and the oxidant gas outlet communication hole 46. The oxidizing gas inlet communication hole 40, the oxidizing gas outlet communication hole 46, the oxidizing gas passage 56, the oxidizing gas inlet buffer 58, the oxidizing gas outlet buffer 60, the inlet A sealing member 63 that integrally surrounds the connection groove 62a and the outlet connection groove 62b and seals the inside with the outside in the surface direction is provided. In the first separator 32, the back surface shape of the oxidizing gas flow path 56 forms a part of the cooling medium flow path 52 (see FIGS. 2 and 3).

  As shown in FIG. 3, a fuel gas flow path 66 communicating with the fuel gas inlet communication hole 44 and the fuel gas outlet communication hole 42 is formed on the surface 36 a on the arrow A1 side of the second separator 36. The fuel gas flow path 66 is composed of a plurality of wavy flow grooves (or straight flow grooves) arranged in parallel with each other. That is, in the present embodiment, each of the oxidizing gas flow path 56 and the fuel gas flow path 66 is not a so-called serpentine type but a straight type.

  A fuel gas inlet buffer 68 is located outside the power generation region at the inlet end of the fuel gas passage 66, and a fuel gas inlet buffer 68 is connected outside the power generation region at the outlet end of the fuel gas passage 66. As a result, the fuel gas outlet buffer 70 is connected. A plurality of fuel gas supply holes 72a penetrating the second separator 36 in the thickness direction are provided between the fuel gas inlet buffer 68 and the fuel gas inlet communication hole 44. A plurality of fuel gas discharge holes 72b penetrating the second separator 36 in the thickness direction are provided between the fuel gas outlet buffer 70 and the fuel gas outlet communication holes 42.

  The surface 36a of the second separator 36 integrally surrounds the fuel gas passage 66, the fuel gas inlet buffer 68, the fuel gas outlet buffer 70, the fuel gas supply hole 72a, and the fuel gas discharge hole 72b. A seal member 73 for sealing the inside with the outside in the surface direction is provided.

  As shown in FIG. 5, the surface 36 b on the arrow A2 side of the second separator 36 is provided with a fuel gas supply hole 72 a and a fuel gas discharge hole 72 b surrounded by a seal member 71, It can be configured similarly to the surface 32b on the arrow A2 side of the first separator 32 (see FIG. 4). That is, the surface 36 b of the second separator 36 is provided with the oxidizing gas passage 56 communicating with the oxidizing gas inlet communication hole 40 and the oxidizing gas outlet communication hole 46. An oxidizing gas inlet buffer 58, an oxidizing gas outlet buffer 60, an inlet connecting groove 62a, an outlet connecting groove 62b, and a seal member 63 are formed on the surface 36b of the second separator 36. .

  On the surface 36b side of the second separator 36, each of the fuel gas supply hole 72a and the fuel gas discharge hole 72b, the oxidizing gas inlet buffer 58 and the oxidizing gas outlet buffer 60 are sealed with seal members 63, 71, and the like. Is blocked by

  As shown in FIG. 3, the surface 38a on the arrow A1 side of the third separator 38 can be configured in the same manner as the surface 36a on the arrow A1 side of the second separator 36. That is, on the surface 38a of the third separator 38, the fuel gas flow path 66 communicating with the fuel gas inlet communication hole 44 and the fuel gas outlet communication hole 42 is provided. Further, a fuel gas inlet buffer 68, a fuel gas outlet buffer 70, a fuel gas supply hole 72a, a fuel gas discharge hole 72b, and a seal member 73 are formed on the surface 38a of the third separator 38. Is done.

  As shown in FIG. 6, the surface 38 b on the arrow A <b> 2 side of the third separator 38 is provided with a fuel gas supply hole 72 a and a fuel gas discharge hole 72 b surrounded by a seal member 71 except for being provided. It can be configured similarly to the surface 32a of the first separator 32 on the arrow A1 side (see FIG. 3). That is, the surface 38 b of the third separator 38 is provided with the cooling medium channel 52, the inlet connection groove 54 a, the outlet connection groove 54 b, and the seal member 55. On the surface 38b side of the third separator 38, each of the fuel gas supply hole 72a and the fuel gas discharge hole 72b, the coolant passage 52, the inlet connection groove 54a, the outlet connection groove 54b, and the like are sealed by the sealing members 55 and 71. And so on.

  As shown in FIG. 2, the coolant flow passage 52 on the surface 38 b on the arrow A2 side of the third separator 38 adjacent to the coolant separator 52 faces the coolant flow passage 52 on the surface 32 a on the arrow A1 side of the first separator 32. Thus, a cooling medium can flow through the inside.

  As shown in FIGS. 3, 5 and 6, in the second separator 36 and the third separator 38, since the sealing members 71 and 73 are provided as described above, the fuel gas inlet communication hole 44 is moved from the arrow A1 side to the arrow A1 side. The fuel gas flowing to the A2 side flows through the fuel gas supply hole 72a from the arrow A2 side to the arrow A1 side, and flows into the fuel gas inlet buffer 68 and the fuel gas flow path 66. The fuel gas flowing through the fuel gas flow path 66 and flowing into the fuel gas outlet buffer 70 flows through the fuel gas discharge hole 72b from the arrow A1 side to the arrow A2 side, and then flows through the fuel gas outlet communication hole 42. Flows from the arrow A2 side to the arrow A1 side.

  On both surfaces of each separator, a sealing member made of an elastic body (not shown) orbiting around the outer peripheral edge of each separator is integrally formed.

  As shown in FIGS. 3, 7 and 8, the resin-framed MEA 34 is configured by joining a resin frame member 82 to an outer periphery of an electrolyte membrane / electrode structure (MEA) 80. As shown in FIG. 8, the electrolyte membrane / electrode structure 80 includes, for example, a solid polymer electrolyte membrane (hereinafter simply referred to as an electrolyte membrane) 84 which is a thin film of perfluorosulfonic acid containing water. The electrolyte membrane 84 may use an HC (hydrocarbon) -based electrolyte in addition to the fluorine-based electrolyte. The electrolyte membrane 84 is sandwiched between the cathode electrode 86 and the anode electrode 88.

  The electrolyte membrane / electrode structure 80 constitutes a step-type MEA in which the plane dimensions of the cathode electrode 86 are smaller than the plane dimensions of the anode electrode 88 and the electrolyte membrane 84. Note that the cathode electrode 86, the anode electrode 88, and the electrolyte membrane 84 may be set to have the same plane dimensions. Further, the anode electrode 88 may have a smaller planar dimension than the cathode electrode 86 and the electrolyte membrane 84.

  The cathode electrode 86 includes a first electrode catalyst layer 90 joined to a surface 84a on one end side (arrow A1 side) of the electrolyte membrane 84 and a first gas diffusion layer 92 laminated on the first electrode catalyst layer 90. Have. The first electrode catalyst layer 90 has a larger planar dimension than the first gas diffusion layer 92, and has an outer peripheral exposed portion 90a that protrudes outward from an outer peripheral end surface 92a of the first gas diffusion layer 92. The first electrode catalyst layer 90 has a smaller planar dimension than the electrolyte membrane 84.

  The anode electrode 88 includes a second electrode catalyst layer 94 joined to a surface 84b on the other end side (arrow A2 side) of the electrolyte membrane 84, and a second gas diffusion layer 96 laminated on the second electrode catalyst layer 94. Having. The second electrode catalyst layer 94 and the second gas diffusion layer 96 have the same plane dimensions and are set to the same (or less than) the plane dimensions of the electrolyte membrane 84.

  The first electrode catalyst layer 90 is formed, for example, by uniformly applying porous carbon particles having a platinum alloy supported on the surface thereof together with an ion-conductive polymer binder to the surface of the first gas diffusion layer 92. The second electrode catalyst layer 94 is formed, for example, by uniformly applying porous carbon particles having a platinum alloy supported on the surface thereof to the surface of the second gas diffusion layer 96 together with an ion conductive polymer binder.

  The first gas diffusion layer 92 and the second gas diffusion layer 96 are formed from a conductive porous body such as carbon paper or carbon cloth. The plane dimension of the second gas diffusion layer 96 is set larger than the plane dimension of the first gas diffusion layer 92.

  The resin frame member 82 is made of, for example, PPS (polyphenylene sulfide), PPA (polyphthalamide), PEN (polyethylene naphthalate), PES (polyether sulfone), LCP (liquid crystal polymer), PVDF (polyvinylidene fluoride), It is composed of a resin material such as silicone resin, fluororesin, m-PPE (modified polyphenylene ether resin), PET (polyethylene terephthalate), PBT (polybutylene terephthalate), or modified polyolefin. This resin material may be composed of, for example, a film or the like.

  As shown in FIG. 3, the resin frame member 82 has a frame shape, and is disposed inside a communication hole group including communication holes 40, 42, 44, 46, 48, 50 including the oxidizing gas inlet communication hole 40, The communication holes 40, 42, 44, 46, 48, 50 are not formed. As shown in FIG. 8, the resin frame member 82 is provided with an outer peripheral edge 82b over a predetermined length inside the outer peripheral end 82a (see FIG. 7), and further inside from the outer peripheral edge 82b. Is provided with an inner bulging portion 82c.

  The inner bulging portion 82c has a shelf 82e extending inward from the inner peripheral end of the outer peripheral edge portion 82b via the first stepped surface 82d, and a shelf 82e extending inward from the inner peripheral end of the shelf 82e. And a thin portion 82g extending through the two-stepped surface 82f. The shelf 82e is thinner than the outer peripheral edge 82b, and the thinner portion 82g is thinner than the shelf 82e. The first step surface 82d, the shelf 82e, the second step surface 82f, and the thin portion 82g are provided over the entire circumference of the resin frame member 82. The outer peripheral edge of the surface 84b of the electrolyte membrane 84 contacts the surface 82ea on the arrow A2 side of the shelf 82e. At the inner end of the thin portion 82g, a bank 82h facing the outer exposed portion 90a of the first electrode catalyst layer 90 is provided over the entire circumference. A groove 82ha is provided between the bank 82h and the second step surface 82f of the thin portion 82g.

  The portion facing the groove portion 82ha of the surface 84a of the electrolyte membrane 84 and the outer peripheral exposed portion 90a of the first electrode catalyst layer 90 are filled with an adhesive 98a so as to go around the outer peripheral exposed portion 90a to provide an adhesive portion 98. . The bonding portion 98 is also filled between the inner peripheral end surface 82i of the resin frame member 82 and the outer peripheral end surface 92a of the first gas diffusion layer 92. As the adhesive 98a, for example, a fluororesin type, a silicone resin type, an epoxy resin type, or the like can be preferably used, but is not particularly limited thereto. Further, the adhesive 98a is not limited to a liquid or a solid, a thermoplastic resin, a thermosetting resin, or the like.

  The resin frame member 82 and the outer peripheral edge of the second gas diffusion layer 96 are integrated by a first joint 100 using an adhesive resin. As shown in FIG. 7, the first joining section 100 is provided so as to go around the outer peripheral edge of the second gas diffusion layer 96. As shown in FIG. 8, for example, the first joint portion 100 is formed of a resin frame member 82 by integrally forming a resin around the inner end of the outer peripheral edge portion 82 b and protruding toward the arrow A2 side. The protrusion 100a can be configured by being deformed by heating. The first joining section 100 is formed from a first resin impregnated section 100b and a first melt-solidified section 100c.

  The first resin-impregnated portion 100b is formed by impregnating the molten resin protrusion 100a into the outer peripheral edge of the second gas diffusion layer 96. The first molten and solidified portion 100c is formed between the first stepped surface 82d of the resin frame member 82 and the outer peripheral end surface 101 of the electrolyte membrane 84 and the anode electrode 88. Is formed by flowing and solidifying. In FIG. 8, the surface of the shelf 82e integrated with the first melt-solidified portion 100c and the first step surface 82d are indicated by two-dot chain lines.

  The bonding portion 98 is provided so as to go around the outer peripheral exposed portion 90a of the first electrode catalyst layer 90 and the outer peripheral end surface 92a of the first gas diffusion layer 92, or to go around the outer peripheral edge of the second gas diffusion layer 96. By providing the first joint portion 100, cross leak between the cathode electrode 86 and the anode electrode 88 and the like are prevented.

  As shown in FIG. 3, an oxidizing gas inlet buffer 102a and an oxidizing gas outlet buffer 102b are provided on a surface 82j of the resin frame member 82 on the cathode electrode 86 side (arrow A1 side). As shown in FIG. 7, a fuel gas inlet buffer portion 104a and a fuel gas outlet buffer portion 104b are provided on a surface 82k of the resin frame member 82 on the anode electrode 88 side (arrow A2 side).

  As shown in FIG. 2, the first end power generation unit 16 includes a dummy first separator 105, a resin frame-attached dummy structure 106, a dummy second separator 108 from the arrow A1 side to the arrow A2 side. The resin-framed MEA 34 and the third separator 38 are stacked in this order.

  As shown in FIGS. 2 to 4, the dummy first separator 105 has the same configuration as the first separator 32. A cooling medium channel 52 is provided on a surface 105a on one end side (arrow A1 side) of the dummy first separator 105. Further, between the surface 105b on the other end side (arrow A2 side) of the dummy first separator 105 and one end side (arrow A1 side) of the dummy structure with resin frame 106 corresponds to the oxidant gas flow path 56. A first space 109 is provided. The first space 109 communicates with the oxidizing gas inlet communication hole 40 and the oxidizing gas outlet communication hole 46 via a communication passage 125 formed in the inlet connection groove 62a and the outlet connection groove 62b. Therefore, the oxidizing gas can be circulated similarly to the oxidizing gas passage 56.

  As shown in FIGS. 9 and 10, the dummy structure with resin frame 106 is configured by joining a dummy resin frame member 111 to the outer periphery of the dummy structure 110. As shown in FIGS. 10 and 11, the dummy structure 110 includes three first conductive porous bodies 112 having different plane dimensions (surface area / outer dimensions), a second conductive porous body 114, The third conductive porous body 116 is stacked in this order from the arrow A1 side to the arrow A2 side.

  The relationship of the magnitude of the planar dimension is such that the first conductive porous body 112 <the second conductive porous body 114 <the third conductive porous body 116. Therefore, as shown in FIG. 10, the outer peripheral edge of the third conductive porous body 116 has an outer periphery protruding outward from the outer peripheral end surface 114 a of the second conductive porous body 114 over the entire periphery. An exposing part 116a is provided. On the outer peripheral edge of the second conductive porous body 114, an outer peripheral exposed portion 114b is provided that protrudes outward from the outer peripheral end surface 112a of the first conductive porous body 112 over the entire circumference.

  The first conductive porous body 112, the second conductive porous body 114, and the third conductive porous body 116 are made of the same material, and the conductive material forming the first gas diffusion layer 92 or the second gas diffusion layer 96 is formed. It can be configured using the same material as the porous material.

  In the present embodiment, the thickness of each of the first conductive porous body 112, the second conductive porous body 114, and the third conductive porous body 116 is set to the conductive thickness of the second gas diffusion layer 96. The thickness was set to be the same as that of the porous body. Thus, the dummy structure 110 can be more easily obtained by adjusting the planar dimensions of the conductive porous body as described above.

  A first conductive porous body 112, a second conductive porous body 114, a third conductive porous body 116, and a vertical lower end (arrow C 2 side) arrow B 2 side end of the dummy structure 110. Are provided in the stacking direction. In the present embodiment, the cross section orthogonal to the axial direction of the through hole 117 is circular, but is not particularly limited to this. Further, the through holes 117 formed in each of the first conductive porous body 112, the second conductive porous body 114, and the third conductive porous body 116 may have the same size as each other. Different dimensions may be used.

  As shown in FIG. 10, the laminated first conductive porous body 112 and second conductive porous body 114 are joined by an adhesive layer 118a, and the second conductive porous body 114 and the third conductive porous body 114 are joined together. The body 116 is joined by the adhesive layer 118b. For the adhesive layers 118a and 118b, an adhesive 98a may be used similarly to the adhesive part 98.

  As shown in FIGS. 9 and 10, the dummy resin frame member 111 has the same configuration as the resin frame member 82 constituting the MEA with resin frame 34 in FIGS. 7 and 8, and has an outer peripheral edge portion 82 b and an inner bulge. A portion 82c. As shown in FIG. 10, the arrow A1 side of the outer peripheral exposed portion 116a of the third conductive porous body 116 contacts the shelf 82e of the inner bulged portion 82c. Part of the outer peripheral exposed portion 116a of the third conductive porous body 116 on the arrow A1 side and part of the outer peripheral exposed portion 114b of the second conductive porous body 114 on the arrow A1 side face the thin portion 82g. . The arrow A1 side of the outer peripheral exposed portion 114b of the second conductive porous body 114 contacts the protruding end surface of the bank portion 82h.

  In the directions of arrows A1 and A2, the outer peripheral end surface 114a of the second conductive porous body 114 is disposed between the third conductive porous body 116 and the thin portion 82g. The inner peripheral end surface 82i of the dummy resin frame member 111 has an outer peripheral end surface 114a of the second conductive porous body 114 and the outer peripheral end surface 114a of the first conductive porous body 112 in a direction perpendicular to the lamination direction (the directions of the arrows A1 and A2). It is located between the outer peripheral end surface 112a. The outer peripheral end surface 112a of the first conductive porous body 112 faces the inner peripheral end surface 82i of the dummy resin frame member 111 at an interval. The height of the second step surface 82f is smaller than the thickness of the second conductive porous body 114.

  The outer peripheral exposed portion 116a of the third conductive porous body 116 and the surface 82ea on the arrow A2 side of the shelf 82e of the dummy resin frame member 111 are joined via the second joining portion 120, thereby providing a resin frame. A dummy structure 106 is configured. As shown in FIG. 9, the second bonding portion 120 is provided intermittently (in a spot shape) in the circumferential direction with respect to the outer peripheral edge of the third conductive porous body 116. The second joint 120 may be formed so as to go around the dummy structure 110.

  As shown in FIG. 10, for example, the second joint portion 120 can be formed by partially heating and deforming a resin protrusion 120 a integrally formed with the dummy resin frame member 111. In this case, the second joining section 120 is formed from the second resin impregnated section 120b and the second melt-solidified section 120c. Note that, of the resin protrusion 120a, a portion that does not constitute the second bonding portion 120, in other words, a portion that remains without being thermally deformed may be removed by machining or the like.

  The second resin impregnated portion 120b is formed by impregnating the outer periphery of the third conductive porous body 116 with the molten resin protrusion 120a. The second melt-solidified portion 120c is provided between the first stepped surface 82d of the dummy resin frame member 111 and the outer peripheral end surface 116b of the third conductive porous body 116. It is formed by flowing the portion 120a and solidifying it. In FIG. 10, the surface of the shelf 82e integrated with the second melt-solidified portion 120c and the first stepped surface 82d are indicated by two-dot chain lines. Note that the first bonding portion 100 and the second bonding portion 120 may use an adhesive 98a as in the case of the bonding portion 98.

  As shown in FIGS. 2, 3 and 12, the dummy second separator 108 is provided with an inlet shut-off portion 122a instead of the fuel gas supply hole 72a, and an outlet shut-off portion 122b instead of the fuel gas exhaust hole 72b. The configuration is the same as that of the second separator 36 except that the second separator 36 is provided. In other words, the surface 108b on the other end side (the arrow A2 side) of the dummy second separator 108 is not provided with the fuel gas supply hole 72a and the fuel gas discharge hole 72b surrounded by the seal member 71. , And the surface 36 b of the second separator 36 on the arrow A2 side. Therefore, the surface 108b of the dummy second separator 108 is configured in the same manner as the surface 32b on the other end side (the arrow A2 side) of the first separator 32 shown in FIG.

  As shown in FIGS. 2 and 4, between the surface 108b on the other end side (arrow A2 side) of the dummy second separator 108 and the cathode electrode 86 side (arrow A1 side) of the MEA 34 with the resin frame, an oxidizing agent is provided. A gas channel 56 is provided.

  As shown in FIGS. 2 and 12, the surface 108a on one end side (arrow A1 side) of the dummy second separator 108 and the other end side (third conductive porous body 116 side, arrow The second space 126 corresponding to the fuel gas flow path 66 is provided between the second space 126 and the A2 side). The second space 126 is shut off from the fuel gas inlet communication hole 44 by the inlet shutoff part 122a, and is shut off from the fuel gas outlet communication hole 42 by the outlet shutoff part 122b. That is, the flow of the fuel gas into the second space 126 is regulated by the inlet blocking portion 122a and the outlet blocking portion 122b (hereinafter, these are also collectively referred to as blocking portions). Forms an adiabatic space.

  In addition, by providing only one of the inlet blocking part 122a and the outlet blocking part 122b, the flow of the fuel gas into the second space 126 may be restricted to form a heat insulating space. Further, in the present embodiment, the shut-off portion is formed by not forming the fuel gas supply hole 72a and the fuel gas discharge hole 72b (see FIG. 3) in the dummy second separator 108. However, the present invention is not particularly limited to this. For example, the shutoff unit may be configured by closing the fuel gas supply hole 72a and the fuel gas discharge hole 72b formed through the dummy second separator 108. It is. As shown in FIG. 12, on the surface 108a of the dummy second separator 108, a sealing member 127 surrounding the second space 126 and sealing the inside with the outside in the surface direction is provided.

  A first space 109 provided on the first conductive porous body 112 side of the dummy structure 110 and a second space 126 provided on the third conductive porous body 116 side of the dummy structure 110 are formed by an oxidizing agent by the through holes 117. It communicates near the gas outlet communication hole 46.

  As shown in FIG. 2, the first dummy cell 18 includes a dummy first separator 105 (dummy separator), a resin frame-attached dummy structure 106, and a dummy second separator 108 (from the arrow A1 side to the arrow A2 side). A dummy structure with a resin frame, a dummy structure with a resin frame 106, and a dummy third separator 130 (dummy separator) are stacked in this order.

  As shown in FIGS. 2 and 3, the surface 130 b on the other end side (arrow A2 side) of the dummy third separator 130 is configured in the same manner as the surface 32 a on one end side (arrow A1 side) of the first separator 32. . As shown in FIGS. 2 and 12, a surface 130a of the dummy third separator 130 on the arrow A1 side is configured in the same manner as the surface 108a of the dummy second separator 108 on the arrow A1 side.

  As shown in FIG. 2, a coolant flow path 52 is provided between a surface 130 b of the dummy third separator 130 on the arrow A2 side and the dummy first separator 105 of the first end power generation unit 16. As shown in FIGS. 2 and 12, between the surface 130a on the arrow A1 side of the dummy third separator 130 and the third conductive porous body 116 side (arrow A2 side) of the dummy structure 106 with a resin frame, A second space 126 corresponding to the fuel gas flow path 66 is provided. Further, in the first dummy cell 18, a second space 126 is also provided between the surface 108a on the arrow A1 side of the dummy second separator 108 and the third conductive porous body 116 side of the dummy structure with resin frame 106. ing.

  In the first dummy cell 18, between the surface 105 b of the dummy first separator 105 on the arrow A2 side and the first conductive porous body 112 side of the dummy structure 106 with a resin frame, and the arrow of the dummy second separator 108. First spaces 109 are respectively formed between the surface 108b on the A2 side and the first conductive porous body 112 side of the dummy structure with resin frame 106.

  The second dummy cell 20 is stacked in the order of the dummy first separator 105, the dummy structure with resin frame 106, and the dummy third separator 130 from the arrow A1 side toward the arrow A2 side. For this reason, in the second dummy cell 20, the first first separator 105 is positioned between the surface 105b on the arrow A2 side and the first conductive porous body 112 side (the arrow A1 side) of the dummy structure with resin frame 106 on the arrow A2 side. A space 109 is provided. Further, a second space 126 is provided between a surface 130a on the arrow A1 side of the dummy third separator 130 and the third conductive porous body 116 side (arrow A2 side) of the dummy structure 106 with a resin frame. The third dummy cell 24 is configured similarly to the second dummy cell 20.

  Note that the separators that can constitute the second dummy cell 20 and the third dummy cell 24 are not limited to the above. For example, the second dummy cell 20 may be configured by stacking the dummy second separator 108, the resin frame-attached dummy structure 106, and the first separator 32 in this order from the arrow A1 side to the arrow A2 side. The third dummy cell 24 may be configured by stacking the first separator 32, the dummy structure with resin frame 106, and the dummy second separator 108 in this order from the arrow A1 side to the arrow A2 side.

  In the first dummy cell 18, the second dummy cell 20, and the third dummy cell 24 (each dummy cell), the first space 109 and the second space 126 facing each other via the dummy structure 110 communicate with the oxidant gas outlet through the through hole 117. It communicates near the hole 46.

  The second end power generation unit 22 includes, from the arrow A1 side to the A2 side, the first separator 32, the MEA with a resin frame 34, the dummy second separator 108, the dummy structure with a resin frame 106, and the dummy third The separator 130 and the separator 130 are stacked in this order. Therefore, in the second end power generation unit 22, the first space 109 is provided between the surface 108b of the dummy second separator 108 on the arrow A2 side and the first conductive porous body 112 side of the dummy structure 106 with the resin frame. Is formed.

  Further, a second space 126 is formed between a surface 130a on the arrow A1 side of the dummy third separator 130 and the third conductive porous body 116 side of the dummy structure 106 with a resin frame. The first space 109 and the second space 126 are also connected by the through hole 117 in the vicinity of the oxidant gas outlet communication hole 46.

  The terminal plates 26a and 26b are made of a material having electrical conductivity, for example, a metal such as copper, aluminum, or stainless steel. As shown in FIG. 1, terminal portions 132a and 132b extending outward in the stacking direction are provided at substantially the centers of the terminal plates 26a and 26b, respectively.

  The terminal portion 132a is inserted into the insulating tubular body 134a, penetrates through the hole 136a of the insulator 28a and the hole 138a of the end plate 30a, and protrudes outside the end plate 30a. The terminal portion 132b is inserted into the insulating cylindrical body 134b, penetrates through the hole 136b of the insulator 28b and the hole 138b of the end plate 30b, and protrudes outside the end plate 30b.

  The insulators 28a and 28b are formed of an insulating material, for example, polycarbonate (PC), phenol resin, or the like. At the center of the insulators 28a and 28b, recesses 140a and 140b that open toward the laminate 14 are formed, and the recesses 140a and 140b communicate with the holes 136a and 136b.

  The insulator 28a and the end plate 30a are provided with reaction gas communication holes. On the other hand, a cooling medium inlet communication hole 48 and a cooling medium outlet communication hole 50 are provided in the insulator 28b and the end plate 30b.

  The recess 140a houses the terminal plate 26a and the heat insulator 142, and the recess 140b houses the terminal plate 26b and the heat insulator 142. The heat insulator 142 is configured such that a heat insulating member 146 having electric conductivity is sandwiched between a pair of heat insulating plates 144 having electric conductivity. The heat insulating plate 144 is formed of, for example, a porous carbon plate having a flat shape, and the heat insulating member 146 is formed of a metal plate having a corrugated cross section.

  Note that the heat insulating plate 144 may be made of the same material as the heat insulating member 146. Further, the heat insulator 142 may include one heat insulating plate 144 and one heat insulating member 146. Furthermore, a resin spacer (not shown) may be interposed between the terminal plates 26a, 26b and the bottoms of the recesses 140a, 140b of the insulators 28a, 28b.

  The operation of the fuel cell stack 10 basically configured as described above will be described below. First, as shown in FIG. 1, an oxidizing gas such as an oxygen-containing gas is supplied to the oxidizing gas inlet communication hole 40 of the end plate 30a. A fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 44 of the end plate 30a. A cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 48 of the end plate 30b.

  The oxidizing gas supplied to the oxidizing gas inlet communication hole 40, as shown in FIGS. 4 and 5, flows through the oxidizing gas flow path 56 and the second oxidizing gas passage 56 through a communication passage 125 formed inside the inlet connection groove 62 a. It flows into one space 109. Thereby, the oxidizing gas moves from the arrow B1 side in the longitudinal direction of each separator and each dummy separator (dummy first separator 105, dummy second separator 108, dummy third separator 130) toward B2 side, The cathode electrode 86 of the electrolyte membrane / electrode structure 80 and the dummy structure 110 are supplied.

  As shown in FIG. 3, the fuel gas supplied to the fuel gas inlet communication hole 44 passes through the inside of the fuel gas supply hole 72 a to the fuel gas flow paths 66 of the second separator 36 and the third separator 38, respectively. Inflow. Thereby, the fuel gas is supplied to the anode electrode 88 of the electrolyte membrane / electrode structure 80 while moving from the arrow B2 side in the longitudinal direction of each separator toward the one side. On the other hand, as shown in FIG. 12, the second space 126 of the dummy second separator 108 and the dummy third separator 130 is blocked by the inlet blocking portion 122a from inflow of fuel gas.

  In the electrolyte membrane / electrode structure 80 to which the reaction gas has been supplied as described above, the oxidant gas supplied to each cathode electrode 86 and the fuel gas supplied to each anode electrode 88 are separated by the first electrode catalyst. Electric power is generated by being consumed by the electrochemical reaction in the layer 90 and the second electrode catalyst layer 94.

  Next, the oxidizing gas supplied to each cathode electrode 86 and partially consumed is passed from each of the oxidizing gas flow path 56 and the first space 109 through the communication passage 125 formed inside the outlet connection groove 62b. Then, the gas is discharged to the oxidant gas outlet communication hole 46. Then, the fuel gas is discharged to the outside of the fuel cell stack 10 through the oxidizing gas outlet communication hole 46 of the end plate 30a.

  Similarly, the fuel gas supplied to each anode electrode 88 and partially consumed is discharged from the fuel gas passage 66 to the fuel gas outlet communication hole 42 through the inside of the fuel gas discharge hole 72b. Then, the fuel gas is discharged to the outside of the fuel cell stack 10 through the fuel gas outlet communication hole 42 of the end plate 30a.

  At this time, the second space 126 is also blocked from the fuel gas outlet communication hole 42 by the outlet blocking portion 122b. For this reason, as described above, in addition to the entry of the fuel gas into the second space 126 by the inlet blocking portion 122a, the fuel gas enters from the fuel gas outlet communication hole 42 by the outlet blocking portion 122b. Have also been avoided. As a result, the flow of the fuel gas is blocked by the blocking portion in the second space 126, and the second space 126 functions as a heat insulating space.

  The cooling medium supplied to each cooling medium inlet communication hole 48 is supplied to the cooling medium passage 52 between the dummy third separator 130 and the first separator 32 adjacent to each other, and the third separator 38 and the first separator 32 is introduced into the cooling medium flow path 52. The cooling medium introduced from each cooling medium inlet communication hole 48 on the arrow C1 side and the cooling medium introduced from the cooling medium inlet communication hole 48 on the arrow C2 side move along the directions of arrows C1 and C2 so as to approach each other. After flowing, it flows toward the arrow B2 side, flows along the directions of arrows C1 and C2 so as to be separated from each other while cooling the electrolyte membrane / electrode structure 80, and from each cooling medium outlet communication hole 50. Is discharged.

  As described above, each dummy cell of the fuel cell stack 10 according to the present embodiment includes the dummy structure 110 corresponding to the electrolyte membrane / electrode structure 80 of the power generation cell 12. That is, since each dummy cell does not include the electrolyte membrane 84, the first electrode catalyst layer 90, and the second electrode catalyst layer 94, no power is generated, and no water is generated by power generation. Accordingly, each dummy cell itself functions as a heat insulating layer, and the occurrence of condensation in each dummy cell can be suppressed.

  By arranging the first dummy cell 18 and the second dummy cell 20 at the end of the stacked body 14 on the arrow A1 side and arranging the third dummy cell 24 at the end of the stacked body 14 on the arrow A2 side, The heat insulation on the end side of the laminate 14 can be improved. For this reason, even in a low-temperature environment, it is possible to suppress the temperature of the end portion of the stacked body 14 from becoming lower than that of the center side.

  Furthermore, since the heat insulation on the end side of the stack 14 can be enhanced, even when the fuel cell stack 10 is started in a sub-zero environment, the entire stack 14 can be effectively heated. As a result, it is possible to prevent the generated water or the like from freezing on the end side of the stacked body 14 and to cause a voltage drop.

  In particular, the oxidizing gas is supplied to the oxidizing gas inlet communication hole 40 from the arrow A1 side in a humidified state. When the water in the oxidizing gas condenses, liquid condensed water is generated, and when the condensed water jumps into the power generation cell 12, the diffusibility of the reaction gas may be reduced.

  Therefore, in the fuel cell stack 10, as described above, one end side (the first conductive porous body 112 side, arrow A1 side) of the dummy structure 106 with the resin frame in the stacking direction, the dummy first separator 105 and the dummy A communication passage 125 is provided between the second separator 108 and the second separator 108. Thus, the oxidizing gas supplied to the oxidizing gas inlet communication hole 40 of each dummy cell flows through the first space 109 via the communication path 125. For this reason, even when the oxidizing gas contains dew water, the dew water can be collected by each dummy cell to prevent the dew water from jumping into the power generation cell 12.

  The liquid water such as dew condensation collected in each dummy cell is generated when the flow rate of the oxidizing gas flowing through the first space 109 is increased during the high-load power generation of the fuel cell stack 10 or during the stopped drying process. Alternatively, when each dummy cell is in a dry state, discharge from each dummy cell is prompted. Since the dummy structure 110 is provided with the through hole 117 that connects the first space 109 and the second space 126 at the lower part in the vertical direction, even if the liquid water enters the second space 126, The liquid water flows toward the through hole 117 by gravity, and is guided to the first space 109 side through the through hole 117.

  As a result, the oxidizing gas flowing in the first space 109 can more effectively promote drainage from each dummy cell, and can prevent liquid water from staying inside each dummy cell. For this reason, it is possible to avoid freezing of each dummy cell even in a low-temperature environment. As described above, according to the fuel cell stack 10, the power generation stability can be improved by the dummy cells in which freezing is suppressed.

  As described above, in the fuel cell stack 10, the through hole 117 of the dummy structure 110 is provided near the oxidant gas outlet communication hole 46. Thereby, the liquid water guided from the second space 126 to the first space 109 via the through hole 117 can be effectively discharged to the outside of each dummy cell (oxidant gas outlet communication hole 46). .

  As described above, in the fuel cell stack 10, each separator and each dummy separator have a rectangular shape whose longitudinal direction is parallel to the horizontal direction. Further, an oxidizing gas inlet communication hole 40 is provided in a vertically upper portion (arrow C1 side) of each separator and each dummy separator, and an oxidizing gas inlet communication hole 40 is provided in a vertically lower portion (arrow C2 side) of each separator and each dummy separator. The outlet communication hole 46 is provided. As a result, the liquid water in each of the power generation cells 12 and each of the dummy cells can be effectively guided to the oxidizing gas outlet communication hole 46 by gravity, and can be drained well.

  As described above, in the fuel cell stack 10, the first space 109 allows the oxidant gas to flow in one direction along the longitudinal direction of each dummy separator. Thus, the liquid water in each dummy cell can be easily guided to the oxidizing gas outlet communication hole 46 through the first space 109 and drained.

  As described above, in the fuel cell stack 10, the other end side (the third conductive porous body 116 side, the arrow A2 side) of the dummy structure 106 with the resin frame in the stacking direction, the dummy second separator 108 and the dummy third An inlet blocking part 122a and an outlet blocking part 122b are provided between each of the separators 130. Thereby, as described above, the second space 126 functions as a heat insulating space, and thus the heat insulating properties of each dummy cell can be further improved. Further, since the flow of the fuel gas to the second space 126 is blocked, the fuel gas discharged from the fuel cell stack 10 can be reduced without contributing to the electrochemical reaction for power generation.

  The present invention is not particularly limited to the embodiment described above, and various modifications can be made without departing from the gist thereof.

  For example, in the above-described embodiment, one circular through-hole 117 is provided in the dummy structure 110 in the vicinity of the oxidizing gas outlet communication hole 46 in plan view. It is not something to be done. The through-hole 117 may be provided at any position as long as it is a vertically lower part of the dummy structure 110. Further, the through hole 117 may have any shape as long as it can communicate with the first space 109 and the second space 126. Further, a plurality of through holes 117 may be provided in the dummy structure 110.

  In the fuel cell stack 10 according to the above-described embodiment, the first end power generation unit 16, the first dummy cell 18, and the second dummy cell 20 are stacked on the arrow A1 side of the stack 14, and the arrow A2 of the stack 14 is stacked. The second end power generation unit 22 and the third dummy cell 24 are stacked on the side.

  In this manner, a greater number of dummy cells are disposed than the arrow A1 side of the laminate 14, in other words, the inlet side of the oxidant gas, than the arrow A2 side of the laminate 14, in other words, the outlet side of the oxidant gas. By doing so, it is possible to more effectively prevent the dew condensation water from entering the power generation cell 12. However, the fuel cell stack 10 only needs to include the dummy cells on at least one end side in the stacking direction of the stack 14, and the number of the dummy cells is not particularly limited.

  In addition, by interposing the first end power generation unit 16 or the second end power generation unit 22 between the power generation cell 12 and the first dummy cell 18 or the third dummy cell 24, both ends of the stacked body 14 in the stacking direction are provided. The electrolyte membrane / electrode structure 80 in the first end power generation unit 16 and the second end power generation unit 22 that perform power generation can be cooled under the same conditions as the other electrolyte membrane / electrode structures 80. . As a result, the balance between heat generation and cooling in the entire stacked body 14 can be made equal, so that power generation performance and power generation stability can be further improved.

  However, the first end power generation unit 16 and the second end power generation unit 22 are not indispensable constituent elements, and the fuel cell stack 10 includes one of the first end power generation unit 16 and the second end power generation unit 22. May be provided, or neither may be provided.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Power generation cell 14 ... Stacked body 18 ... 1st dummy cell 20 ... 2nd dummy cell 24 ... 3rd dummy cell 46 ... Oxidant gas outlet communication hole 56 ... Oxidant gas flow path 66 ... Fuel gas flow path 106 ... Dummy structure with resin frame 109 ... First space 110 ... Dummy structure 111 ... Dummy resin frame member 117 ... Through hole 125 ... Communication passage 126 ... Second space

Claims (8)

Electrolyte membrane / electrode structure in which electrodes each having a gas diffusion layer made of a conductive porous body are disposed on both sides of the electrolyte membrane, and a resin frame member orbiting the outer periphery of the electrolyte membrane / electrode structure, A fuel cell stack including a stack in which a plurality of power generation cells having an electrolyte membrane and an electrode structure sandwiching the separator are stacked, and a dummy cell disposed at at least one end in the stacking direction of the stack.
The dummy cell includes a dummy structure corresponding to the electrolyte membrane / electrode structure, a dummy resin frame member surrounding the outer periphery of the dummy structure, and a dummy separator sandwiching the dummy structure.
The dummy structure is formed by stacking three conductive porous bodies having different plane dimensions,
In each of the separator and the dummy separator, an oxidizing gas communication hole that allows an oxidizing gas to flow in the stacking direction of the stack and a fuel gas communication hole that allows a fuel gas to flow in the stacking direction of the stack are formed. And
The separator facing the one electrode of the electrolyte membrane / electrode structure is provided with an oxidizing gas flow path through which an oxidizing gas flows,
The separator facing the other electrode of the electrolyte membrane / electrode structure is provided with a fuel gas flow path through which fuel gas flows,
A first space corresponding to the oxidant gas flow path is provided between the dummy separator and one end of the dummy structure facing one end of the dummy structure in the stacking direction,
A second space corresponding to the fuel gas flow path is provided between the dummy separator facing the other end of the dummy structure in the stacking direction and the other end of the dummy structure,
A communication passage that allows the oxidant gas to flow is provided between the oxidant gas communication hole and the first space,
The fuel cell stack according to claim 1, wherein the dummy structure is provided with a through-hole communicating the first space and the second space at a vertically lower portion. The fuel cell stack according to claim 1,
The fuel cell stack according to claim 1, wherein the through hole of the dummy structure is provided in the vicinity of the oxidizing gas communication hole on the outlet side of the oxidizing gas flowing through the first space. The fuel cell stack according to claim 1 or 2,
The separator and the dummy separator are rectangular in a longitudinal direction along a horizontal direction,
The oxidant gas communication hole on the inlet side for supplying the oxidant gas to the oxidant gas flow path and the first space is provided in a vertically upper part of the separator and the dummy separator,
The oxidizing gas communication hole on the outlet side where the oxidizing gas is discharged from the oxidizing gas flow path and the first space is provided in a vertically lower portion of the separator and the dummy separator. Fuel cell stack. The fuel cell stack according to any one of claims 1 to 3,
The fuel cell stack according to claim 1, wherein the first space allows the oxidant gas to flow in one direction along a longitudinal direction of the dummy separator. The fuel cell stack according to any one of claims 1 to 4,
A fuel cell stack, characterized in that a cut-off portion for cutting off the flow of the fuel gas is provided between the fuel gas communication hole and the second space. The fuel cell stack according to any one of claims 1 to 5,
The three conductive porous bodies include a first conductive porous body, a second conductive porous body having a larger planar dimension than the first conductive porous body, and a second conductive porous body. A third conductive porous body having a larger planar dimension than the body,
The dummy resin frame member has an outer peripheral edge, a shelf protruding inward over the entire circumference from the inner peripheral end of the outer peripheral edge via the first step surface, and an inner peripheral end of the shelf. A thin portion protruding inward over the entire circumference via the second step surface,
An outer peripheral edge of the third conductive porous body overlaps the shelf of the dummy resin frame member;
The outer peripheral edge of the second conductive porous body faces the thin portion of the dummy resin frame member,
The fuel cell stack according to claim 1, wherein an outer peripheral end surface of the first conductive porous body faces an inner peripheral end surface of the dummy resin frame member. The fuel cell stack according to claim 6,
The fuel cell stack according to claim 1, wherein a thickness of the second conductive porous body is larger than a height of the second step surface. The fuel cell stack according to claim 6 or 7,
A fuel cell stack, wherein a space is formed between the thin portion of the dummy resin frame member and the third conductive porous body.

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