JP7104008B2 - Fuel cell stack - Google Patents

Description

The present invention relates to a fuel cell stack in which dummy cells are laminated at at least one end in a stacking direction of a laminated body in which a plurality of power generation cells are stacked.

Generally, a polymer electrolyte fuel cell employs a solid polymer electrolyte membrane (hereinafter, also simply referred to as an electrolyte membrane) made of a polymer ion exchange membrane. The fuel cell includes an electrolyte membrane / electrode structure (MEA) in which an anode electrode is disposed on one surface of the electrolyte membrane and a cathode electrode is disposed on the other surface.

A power generation cell is formed by sandwiching the electrolyte membrane / electrode structure with a separator, and a laminated body is formed by laminating a plurality of power generation cells. A fuel cell stack is configured by providing terminal plates for collecting electric charges generated by each power generation cell, end plates for holding the power generation cells in a stacked state, and the like at both ends of the stack in the stacking direction. To.

By the way, the end side of the laminated body in the laminating direction (hereinafter, also simply referred to as the end side) is lower in temperature than the central side in the laminating direction of the laminated body because heat dissipation is promoted through the terminal plate or the like. easy. If the end side of the laminate becomes cold due to the influence of the outside temperature and dew condensation occurs, the diffusivity of the fuel gas and oxidant gas (reaction gas) will decrease, and there is a concern that the power generation stability of the fuel cell stack will decrease. be.

Therefore, for example, in the fuel cell stack disclosed in Patent Document 1, so-called dummy cells are arranged on at least one end side of the laminated body in the stacking direction. Since this dummy cell uses a metal plate instead of the electrolyte membrane, it does not generate electricity and does not generate generated water. Therefore, the dummy cell itself functions as a heat insulating layer between the terminal plate and the laminated body. Therefore, by arranging the dummy cells as described above, it is possible to suppress the temperature drop on the end side of the laminated 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. 4727972

The present invention has been made in connection with this kind of technique, and an object of the present invention is to provide a fuel cell stack capable of improving low temperature startability and power generation stability.

One aspect of the present invention includes a laminated body in which a plurality of power generation cells are laminated, and a dummy structure in which the laminated bodies are laminated at at least one end in the stacking direction, and each power generation cell is a first electrolyte. It has a film / electrode structure, a second electrolyte film / electrode structure, a first separator, a second separator, and a third separator, and the first separator, the first electrolyte film / electrode structure, and the like. A fuel cell stack in which the second separator, the second electrolyte film / electrode structure, and the third separator are laminated in this order, and the dummy structure is a dummy conductor corresponding to the electrolyte film / electrode structure. The end power generation cell, which is the power generation cell having the dummy separator sandwiching the dummy conductor and arranged at the end of the stack in the stacking direction, and the end power generation cell adjacent to the end power generation cell. A cooling medium flow path through which a cooling medium flows is provided between the dummy structure and the dummy structure, and the dummy structure has an end dummy cell arranged at an outer end portion in the stacking direction, and the end dummy cell is provided. , The dummy conductor is sandwiched between the two dummy separators .

In this fuel cell stack, a cooling medium flow path through which a cooling medium flows is provided between an end power generation cell and a dummy structure adjacent to the end power generation cell. For example, when the fuel cell stack is started (low temperature start) in a low temperature environment such as below freezing point, the temperature of the cooling medium becomes higher than that of the end power generation cell due to power generation or the like. Therefore, by providing the cooling medium flow path as described above and facilitating the heat transfer of the cooling medium flowing through the cooling medium flow path to the end power generation cell, the end power generation cell can be easily transferred even in a low temperature environment. It becomes possible to raise the temperature quickly. As a result, the low temperature startability of the fuel cell stack can be improved.

Further, the dummy cell includes a dummy conductor instead of the electrolyte membrane / electrode structure of the power generation cell. That is, since the dummy cell does not have a solid polymer electrolyte membrane or an electrode catalyst layer, it does not generate electricity and does not generate water generated by the power generation. As a result, the dummy cell itself functions as a heat insulating layer, and the formation of dew condensation on the dummy cell can be suppressed. By laminating such dummy cells on at least one end side of the laminated body in the laminating direction, the heat insulating property on the end side of the laminated body can be improved. Therefore, it is possible to prevent the temperature on the end side of the laminated body from becoming lower than that on the center side, thereby improving the power generation stability of the fuel cell stack.

It is an exploded perspective view of the fuel cell stack which concerns on embodiment of this invention. FIG. 2 is a cross-sectional view taken along the line II-II of the fuel cell stack of FIG. It is an exploded perspective view of a power generation cell. It is a front view of the oxidant gas flow path side of the 1st separator (the 1st space side of the 1st dummy separator and the 2nd dummy separator). 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 flow path side of the 3rd separator. It is a front view of the 2nd dummy separator and the 3rd dummy separator on the 2nd space side.

A suitable embodiment of the fuel cell stack according to the present invention will be described in detail with reference to the accompanying drawings. In the following figures, components having the same or similar functions and effects may be designated by the same reference numerals, and repeated description may be omitted.

As shown in FIGS. 1 and 2, in the fuel cell stack 10 according to the present embodiment, a plurality of power generation cells 12 are stacked in the horizontal direction (arrows A1 and A2 directions) or in the gravity direction (arrows C1 and C2 directions). The laminated body 14 is provided. 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, in the following, the power generation cell 12 arranged on one end side (arrow A1 side) of the laminated body 14 in the stacking direction is also referred to as a first end power generation cell 12a. Further, the power generation cell 12 arranged on the other end side (arrow A2 side) of the laminated body 14 in the stacking direction is also referred to as a second end power generation cell 12b. In the present embodiment, each of the first-end power generation cell 12a and the second-end power generation cell 12b is arranged at the end of the laminated body 14 in the stacking direction.

A dummy structure 15a is laminated on the first end power generation cell 12a of the laminated body 14. The dummy structure 15a has an intermediate dummy cell 16 and a first end dummy cell 18. That is, the intermediate dummy cell 16 and the first end dummy cell 18 are laminated outward in this order on the first end power generation cell 12a.

Further, a dummy structure 15b is laminated on the second end power generation cell 12b of the laminated body 14. The dummy structure 15b has a second end dummy cell 20. That is, the second end dummy cell 20 is laminated on the second end power generation cell 12b. The intermediate dummy cell 16, the first end dummy cell 18, and the second end dummy cell 20 are also collectively referred to as a “dummy cell”.

The terminal plate 26a, the insulator 28a, and the end plate 30a are laminated in this order on the outer side (arrow A1 side) of the first end dummy cell 18 of the laminated body 14. The terminal plate 26b, the insulator 28b, and the end plate 30b are laminated in this order on the outer side (arrow A2 side) of the second end dummy cell 20 of the laminated body 14.

As shown in FIG. 1, a connecting bar (not shown) is arranged between each side of the rectangular end plates 30a and 30b. Both ends of each connecting bar are fixed to the inner surfaces of the end plates 30a and 30b via bolts (not shown), and a tightening load in the stacking direction (arrows A1 and A2) is applied to the plurality of stacked power generation cells 12. do. Although not shown, the fuel cell stack 10 may include a housing having end plates 30a and 30b as end plates, and may be configured to accommodate the laminated body 14 and the like in the housing.

As shown in FIG. 3, the power generation cell 12 includes a first separator 32, a first electrolyte membrane / electrode structure 34a, a second separator 36, a second electrolyte membrane / electrode structure 34b, and a third separator 38. And are laminated in this order. Each of the first separator 32, the second separator 36, and the third separator 38 (collectively referred to as "separator") is composed of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or the like, and has a flat surface. In addition to being rectangular, it is formed into an uneven cross-sectional shape by press working or the like.

As shown in FIG. 3, the oxidants are individually communicated with the edges of the separators 32, 36, and 38 on the long side direction (arrow B1 side) in the arrow A1 and A2 directions (stacking directions), respectively. A gas inlet communication hole 40 and a fuel gas outlet communication hole 42 are provided. An oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 40. A fuel gas such as a hydrogen-containing gas is discharged to the fuel gas outlet communication hole 42. These oxidant gas and fuel gas are also collectively referred to as reaction gas.

Fuel gas inlet communication holes 44 to which fuel gas is supplied by individually communicating with the edges of the separators 32, 36, and 38 on the other end side (arrow B2 side) in the long side direction in the directions of arrows A1 and A2, respectively. And the oxidant gas outlet communication hole 46 from which the oxidant gas is discharged is provided. The oxidant gas inlet communication hole 40, the fuel gas outlet communication hole 42, the fuel gas inlet communication hole 44, and the oxidizer gas outlet communication hole 46 are also collectively referred to as “reaction gas communication hole”.

A pair of cooling medium inlets to which cooling media are supplied by individually communicating in the arrows A1 and A2 directions on the arrow B1 side of both end edges of the separators 32, 36, and 38 in the short side directions (arrows C1 and C2 directions). Communication holes 48 are provided respectively. As the cooling medium, pure water, ethylene glycol, oil or the like can be used. A pair of cooling medium outlet communication holes 50 are provided on the arrow B2 side of both end edges of the separators 32, 36, and 38 in the short side direction so as to communicate individually in the arrows A1 and A2 directions and discharge the cooling medium. Be done.

As shown in FIG. 3, a cooling medium flow path 52 that communicates the cooling medium inlet communication hole 48 and the cooling medium outlet communication hole 50 is formed on the surface 32a of the first separator 32 on the arrow A1 side. A plurality of inlet connecting grooves 54a are formed between the cooling medium inlet communication hole 48 and the cooling medium flow path 52. A plurality of outlet connecting grooves 54b are formed between the cooling medium flow path 52 and the cooling medium outlet communication hole 50. Further, on the surface 32a of the first separator 32, the cooling medium inlet communication hole 48, the cooling medium outlet communication hole 50, the cooling medium flow path 52, the inlet connecting groove 54a, and the outlet connecting groove 54b are integrally surrounded, and the inside thereof is surrounded. A sealing member 55 that seals the outside in the surface direction is provided.

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

The oxidant gas inlet buffer portion 58 located outside the power generation region is connected to the inlet side end of the oxidant gas flow path 56, while the outlet side end of the oxidant gas flow path 56 is outside the power generation region. The oxidant gas outlet buffer portion 60 is connected to the position at.

A plurality of inlet connecting grooves 62a are formed between the oxidant gas inlet buffer portion 58 and the oxidant gas inlet communication hole 40. A plurality of outlet connecting grooves 62b are formed between the oxidant gas outlet buffer portion 60 and the oxidant gas outlet communication hole 46. On the surface 32b of the first separator 32, an oxidant gas inlet communication hole 40, an oxidizer gas outlet communication hole 46, an oxidizer gas flow path 56, an oxidizer gas inlet buffer portion 58, an oxidizer gas outlet buffer portion 60, and an inlet A sealing member 63 is provided that integrally surrounds the connecting groove 62a and the outlet connecting groove 62b and seals the inside thereof with the outside in the surface direction. In the first separator 32, the shape of the back surface of the oxidant 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 36a of the second separator 36 on the arrow A1 side. The fuel gas flow path 66 is composed of a plurality of wavy flow path grooves (or linear flow path grooves) that are parallel to each other.

The fuel gas inlet buffer portion 68 is connected to the inlet side end of the fuel gas flow path 66 located outside the power generation region, while the outlet side end of the fuel gas flow path 66 is located outside the power generation region. The fuel gas outlet buffer section 70 is connected to the fuel gas outlet buffer section 70. 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 portion 68 and the fuel gas inlet communication hole 44. A plurality of fuel gas discharge holes 72b that penetrate the second separator 36 in the thickness direction are provided between the fuel gas outlet buffer portion 70 and the fuel gas outlet communication hole 42.

A fuel gas flow path 66, a fuel gas inlet buffer portion 68, a fuel gas outlet buffer portion 70, a fuel gas supply hole portion 72a, and a fuel gas discharge hole portion 72b are integrally surrounded on the surface 36a of the second separator 36. A sealing member 73 is provided to seal the inside with the outside in the surface direction.

As shown in FIG. 5, the surface 36b on the arrow A2 side of the second separator 36 is provided with the fuel gas supply hole 72a and the fuel gas discharge hole 72b surrounded by the seal member 71, except that the surface 36b is provided with the fuel gas discharge hole 72b. It can be configured in the same manner as the surface 32b (see FIG. 4) on the arrow A2 side of the first separator 32. That is, the surface 36b of the second separator 36 is provided with an oxidant gas flow path 56 that communicates with the oxidant gas inlet communication hole 40 and the oxidant gas outlet communication hole 46. Further, on the surface 36b of the second separator 36, an oxidant gas inlet buffer portion 58, an oxidant gas outlet buffer portion 60, an inlet connecting groove 62a, an outlet connecting groove 62b, and a seal member 63 are formed. ..

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, and the oxidant gas inlet buffer portion 58 and the oxidant gas outlet buffer portion 60 are sealed by the sealing members 63 and 71. It is blocked.

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, the surface 38a of the third separator 38 is provided with a fuel gas flow path 66 that communicates with the fuel gas inlet communication hole 44 and the fuel gas outlet communication hole 42. Further, on the surface 38a of the third separator 38, a fuel gas inlet buffer portion 68, a fuel gas outlet buffer portion 70, a fuel gas supply hole portion 72a, a fuel gas discharge hole portion 72b, and a seal member 73 are formed. Will be done.

As shown in FIG. 6, the surface 38b on the arrow A2 side of the third separator 38 is provided with the fuel gas supply hole portion 72a and the fuel gas discharge hole portion 72b surrounded by the seal member 71, except that the fuel gas supply hole portion 72a and the fuel gas discharge hole portion 72b are provided. It can be configured in the same manner as the surface 32a (see FIG. 3) on the arrow A1 side of the first separator 32. That is, the surface 38b of the third separator 38 is provided with the cooling medium flow path 52, the inlet connecting groove 54a, the outlet connecting groove 54b, 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 cooling medium flow path 52, the inlet connecting groove 54a, the outlet connecting groove 54b, and the like are sealed members 55 and 71. Is blocked by.

As shown in FIG. 2, in the power generation cells 12 adjacent to each other in the laminated body 14, the cooling medium flow path 52 of the surface 38b on the arrow A2 side of the third separator 38 and the surface 32a on the arrow A1 side of the first separator 32 The cooling medium flow path 52 faces the cooling medium flow path 52, and the cooling medium can flow through the inside thereof. That is, in the laminated body 14, a cooling medium flow path 52 through which a cooling medium flows is provided between adjacent power generation cells 12.

As shown in FIGS. 3, 5 and 6, since the sealing members 71 and 73 are provided in the second separator 36 and the third separator 38 as described above, the fuel gas inlet communication hole 44 is indicated by an arrow from the arrow A1 side. The fuel gas flowing to the A2 side flows through the fuel gas supply hole portion 72a from the arrow A2 side to the arrow A1 side and flows into the fuel gas inlet buffer portion 68 and the fuel gas flow path 66. Further, the fuel gas flowing through the fuel gas flow path 66 and flowing into the fuel gas outlet buffer portion 70 flows through the fuel gas discharge hole portion 72b from the arrow A1 side to the arrow A2 side, and then the fuel gas outlet communication hole 42. Is circulated from the arrow A2 side to the arrow A1 side. On both sides of each of the separators 32, 36, 38, a sealing member made of an elastic body (not shown) orbiting the outer peripheral edge of the separators 32, 36, 38 is integrally molded.

As shown in FIG. 3, the first electrolyte membrane / electrode structure 34a and the second electrolyte membrane / electrode structure 34b are configured in substantially the same manner as each other. These first electrolyte membrane / electrode structure 34a and second electrolyte membrane / electrode structure 34b are also collectively referred to as "electrolyte film / electrode structure". A resin frame member 82 is bonded to the outer periphery of the electrolyte membrane / electrode structures 34a and 34b. As shown in FIG. 2, the electrolyte membrane / electrode structures 34a and 34b include, for example, a solid polymer electrolyte membrane (hereinafter, also simply referred to as an electrolyte membrane) 84 which is a thin film of perfluorosulfonic acid containing water. In addition to the fluorine-based electrolyte, the electrolyte membrane 84 may use an HC (hydrocarbon) -based electrolyte. The electrolyte membrane 84 is sandwiched between the cathode electrode 86 and the anode electrode 88.

The cathode electrode 86 includes a first electrode catalyst layer (not shown) bonded to a surface on one end side (arrow A1 side) of the electrolyte film 84, and a first gas diffusion layer 92 laminated on the first electrode catalyst layer. Have. The anode electrode 88 includes a second electrode catalyst layer (not shown) bonded to the other end side (arrow A2 side) of the electrolyte film 84, and a second gas diffusion layer 96 laminated on the second electrode catalyst layer. Has.

The first electrode catalyst layer is formed, for example, by uniformly coating the surface of the first gas diffusion layer 92 with porous carbon particles on which a platinum alloy is supported on the surface together with an ion conductive polymer binder. The second electrode catalyst layer is formed, for example, by uniformly coating the surface of the second gas diffusion layer 96 together with porous carbon particles on which a platinum alloy is supported on the surface together with an ion conductive polymer binder. The first gas diffusion layer 92 and the second gas diffusion layer 96 are formed of a conductive porous body such as carbon paper or carbon cloth.

The resin frame member 82 includes, for example, PPS (polyphenylene sulfide), PPA (polyphthalamide), PEN (polyethylene naphthalate), PES (polyester sulfone), LCP (liquid crystal polymer), PVDF (polyfluoride vinylidene), and the like. 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 made of, for example, a film or the like.

As shown in FIG. 3, the resin frame member 82 has a frame shape and is arranged inside a communication hole group including communication holes 40, 42, 44, 46, 48, 50 including an oxidant gas inlet communication hole 40. The communication holes 40, 42, 44, 46, 48, 50 are not formed. An oxidant gas inlet buffer portion 102a and an oxidant gas outlet buffer portion 102b are provided on the surface of the resin frame member 82 on the cathode electrode 86 side (arrow A1 side). Although not shown, a fuel gas inlet buffer portion and a fuel gas outlet buffer portion are provided on the surface of the resin frame member 82 on the anode electrode 88 side (arrow A2 side).

As shown in FIG. 2, the intermediate dummy cell 16 adjacent to the outside of the first end power generation cell 12a of the laminated body 14 in the stacking direction (arrow A1 side) is a first dummy separator from the arrow A1 side toward the arrow A2 side. The 105, the first dummy conductor 106a, the second dummy separator 108, the second dummy conductor 106b, and the third dummy separator 130 are laminated and formed in this order. The first dummy conductor 106a and the second dummy conductor 106b are configured in substantially the same manner as each other. These first dummy conductor 106a and second dummy conductor 106b are also collectively referred to as "dummy conductor".

As shown in FIGS. 2 to 4, the first dummy separator 105 (FIGS. 2 and 4) is configured in the same manner as the first separator 32. That is, a cooling medium flow path 52 (see FIG. 3) is provided on the surface 105a on one end side (arrow A1 side) of the first dummy separator 105. Further, as shown in FIG. 2, between the surface 105b on the other end side (arrow A2 side) of the first dummy separator 105 and the first dummy conductor 106a, a first one corresponding to the oxidant gas flow path 56 is formed. Space 109 is provided.

As shown in FIG. 4, the first space 109 includes the oxidant gas inlet communication hole 40 and the oxidant gas outlet communication hole 46 via the communication passage 125 formed in the inlet connecting groove 62a and the outlet connecting groove 62b. Communicate with. Therefore, the oxidant gas can be circulated in the same manner as the oxidant gas flow path 56.

As shown in FIG. 2, the dummy conductors 106a and 106b are formed by stacking three conductive porous bodies 107 having different plane dimensions (surface area / external dimensions). The three conductive porous bodies 107 are made of, for example, the same materials as each other, and are made of the same material as the conductive porous bodies constituting the first gas diffusion layer 92 or the second gas diffusion layer 96. be able to. The dummy conductors 106a and 106b are not limited to the above configuration, and may be any member exhibiting conductivity, and the number of the members is not particularly limited.

A dummy resin frame member (not shown) is integrated on the outer periphery of the dummy conductors 106a and 106b. The dummy resin frame member can be configured in substantially the same manner as the resin frame member 82 of the power generation cell 12 shown in FIG.

As shown in FIG. 7, the second dummy separator 108 is provided with an inlet blocking portion 122a in place of the fuel gas supply hole portion 72a (see FIG. 3), and replaces the fuel gas discharge hole portion 72b (see FIG. 3). It is configured in the same manner as the second separator 36 (see FIG. 3) except that the outlet blocking portion 122b is provided.

That is, on the surface 108b (see FIG. 2) on the other end side (arrow A2 side) of the second dummy separator 108, the fuel gas supply hole portion 72a and the fuel gas discharge hole portion 72b surrounded by the seal member 71 of FIG. 5 are formed. It is configured in the same manner as the surface 36b on the arrow A2 side of the second separator 36, except that it is not provided. Therefore, the surface 108b of the second dummy separator 108 is configured in the same manner as the surface 32b on the other end side (arrow A2 side) of the first separator 32 shown in FIG.

As shown in FIG. 2, between the surface 108b on the other end side (arrow A2 side) of the second dummy separator 108 and the second dummy conductor 106b, a first space 109 corresponding to the oxidant gas flow path 56 Is provided. As shown in FIGS. 2 and 7, a second space corresponding to the fuel gas flow path 66 is provided between the surface 108a on one end side (arrow A1 side) of the second dummy separator 108 and the first dummy conductor 106a. 126 is provided.

The second space 126 is blocked from the fuel gas inlet communication hole 44 by the inlet blocking portion 122a, and is blocked from the fuel gas outlet communication hole 42 by the outlet blocking portion 122b. That is, since the inlet blocking portion 122a and the outlet blocking portion 122b (hereinafter, collectively referred to as a blocking portion) regulate the flow of fuel gas into the second space 126, the inside of the second space 126 is inside. A heat insulating space is formed. By providing only one of the inlet blocking portion 122a and the outlet blocking portion 122b, the flow of fuel gas to the second space 126 may be restricted and a heat insulating space may be formed.

As shown in FIG. 7, on the surface 108a on one end side (arrow A1 side) of the second dummy separator 108, a sealing member 127 that surrounds the second space 126 and seals the inside thereof with the outside in the surface direction is provided. ing.

The surface 130b on the other end side (arrow A2 side) of the third dummy separator 130 in FIG. 2 is configured to have a substantially mirror image relationship with the surface 32a on one end side (arrow A1 side) of the first separator 32 shown in FIG. .. Further, as shown in FIG. 7, the surface 130a on one end side (arrow A1 side) of the third dummy separator 130 is configured in the same manner as the surface 108a on one end side (arrow A1 side) of the second dummy separator 108.

As shown in FIG. 2, a cooling medium flow path 52 is provided between the surface 130b on the other end side (arrow A2 side) of the third dummy separator 130 and the first separator 32 of the first end power generation cell 12a. Further, a second space 126 corresponding to the fuel gas flow path 66 is provided between the surface 130a on one end side (arrow A1 side) of the third dummy separator 130 and the second dummy conductor 106b.

The first end dummy cell 18 is provided adjacent to the outside of the intermediate dummy cell 16 in the stacking direction (arrow A1 side). That is, the intermediate dummy cell 16 is arranged between the first end power generation cell 12a and the first end dummy cell 18. The first end dummy cell 18 is formed by laminating a second dummy separator 108, a second dummy conductor 106b, and a third dummy separator 130 in this order from the arrow A1 side to the arrow A2 side.

Therefore, in the first end dummy cell 18, the first space is between the surface 108b on the arrow A2 side of the second dummy separator 108 arranged on the outside in the stacking direction (arrow A1 side) and the second dummy conductor 106b. 109 is provided. A second space 126 is provided between the surface 108a on the arrow A1 side of the second dummy separator 108 and the heat insulating body 142 described later.

Further, in the first end dummy cell 18, the second space 126 is between the surface 130a on the arrow A1 side of the third dummy separator 130 arranged inside the stacking direction (arrow A2 side) and the second dummy conductor 106b. Is provided. A cooling medium flow path 52 is provided between the surface 130b on the arrow A2 side of the third dummy separator 130 and the first dummy separator 105 of the intermediate dummy cell 16.

The second end dummy cell 20 adjacent to the outer side (arrow A2 side) of the second end power generation cell 12b of the laminated body 14 is the first dummy separator 105 and the first dummy cell separator 105 from the arrow A1 side toward the arrow A2 side. The 1 dummy conductor 106a and the second dummy separator 108 are laminated and formed in this order.

Therefore, in the second end dummy cell 20, the surface 105a on the arrow A1 side of the first dummy separator 105 arranged inside the stacking direction (arrow A1 side) and the third separator 38 of the second end power generation cell 12b. A cooling medium flow path 52 is provided between the two. A first space 109 is provided between the surface 105b on the arrow A2 side of the first dummy separator 105 and the first dummy conductor 106a.

Further, in the second end dummy cell 20, the second space 126 is between the surface 108a on the arrow A1 side of the second dummy separator 108 arranged on the outside in the stacking direction (arrow A2 side) and the first dummy conductor 106a. Is provided. A first space 109 is provided between the surface 108b on the arrow A2 side of the second dummy separator 108 and the heat insulating body 142.

The separators that can form the first end dummy cell 18 and the second end dummy cell 20 are not limited to the above. For example, the first end dummy cell 18 may be formed by stacking the second dummy separator 108, the first dummy conductor 106a, and the first dummy separator 105 in this order from the arrow A1 side to the arrow A2 side. The second end dummy cell 20 may be formed by laminating the third dummy separator 130, the second dummy conductor 106b, and the second dummy separator 108 in this order from the arrow A1 side to the arrow A2 side.

The terminal plates 26a and 26b are made of a conductive material, 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 center of the terminal plates 26a and 26b, respectively.

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

The insulators 28a and 28b are made of an insulating material such as polycarbonate (PC) or phenol resin. Recesses 140a and 140b opened toward the laminated body 14 are formed in the central portions of the insulators 28a and 28b, 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, the insulator 28b and the end plate 30b are provided with a cooling medium inlet communication hole 48 and a cooling medium outlet communication hole 50.

The recess 140a houses the terminal plate 26a and the heat insulating body 142, and the recess 140b houses the terminal plate 26b and the heat insulating body 142. The heat insulating body 142 is configured by sandwiching a conductive heat insulating member 146 between a pair of conductive heat insulating plates 144. The heat insulating plate 144 is made of, for example, a porous carbon plate having a flat shape, and the heat insulating member 146 is made of a metal plate having a corrugated cross section.

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

Basically, the operation of the fuel cell stack 10 configured as described above will be described. First, as shown in FIG. 1, the oxidant gas is supplied to the oxidant gas inlet communication hole 40 of the end plate 30a arranged on the arrow A1 side, and the fuel gas is supplied to the fuel gas inlet communication hole 44. The cooling medium is supplied to the cooling medium inlet communication hole 48 of the end plate 30b arranged on the A2 side.

As shown in FIGS. 4 and 5, the oxidant gas supplied to the oxidant gas inlet communication hole 40 passes through the oxidant gas flow path 56 and the second passage 125 formed inside the inlet connecting groove 62a. It flows into one space 109. As a result, the oxidant gas is supplied to the cathode electrodes 86 of the electrolyte membrane / electrode structures 34a and 34b and the dummy conductors 106a and 106b while moving in the directions of arrows B1 and B2.

As shown in FIG. 3, the fuel gas supplied to the fuel gas inlet communication hole 44 flows into the fuel gas flow path 66 of the second separator 36 and the third separator 38, respectively, through the fuel gas supply hole portion 72a. .. As a result, the fuel gas is supplied to the anode electrodes 88 of the electrolyte membrane / electrode structures 34a and 34b while moving in the directions of arrows B1 and B2. On the other hand, as shown in FIG. 7, the inflow of fuel gas is blocked by the inlet blocking portion 122a in the second space 126 of the second dummy separator 108 and the third dummy separator 130.

In the electrolyte membrane / electrode structures 34a and 34b to which the reaction gas is supplied as described above, the oxidant gas supplied to each cathode electrode 86 and the fuel gas supplied to each anode electrode 88 are first. Power is generated by being consumed by an electrochemical reaction in the electrode catalyst layer and the second electrode catalyst layer.

Next, as shown in FIGS. 4 and 5, the oxidant gas supplied to each cathode electrode 86 and partially consumed is discharged from each of the oxidant gas flow path 56 and the first space 109 to the outlet connecting groove 62b. It is discharged to the oxidant gas outlet communication hole 46 through the communication passage 125 formed inside. Then, it is discharged to the outside of the fuel cell stack 10 through the oxidant gas outlet communication hole 46 of the end plate 30a of FIG.

Similarly, as shown in FIG. 3, the fuel gas supplied to each anode electrode 88 and partially consumed is a fuel gas outlet communication hole from the fuel gas flow path 66 through the inside of the fuel gas discharge hole 72b. It is discharged to 42. Then, it is discharged to the outside of the fuel cell stack 10 through the fuel gas outlet communication hole 42 of the end plate 30a of FIG.

At this time, as shown in FIG. 7, the second space 126 is also blocked from the fuel gas outlet communication hole 42 by the outlet blocking portion 122b. Therefore, as described above, the inflow of fuel gas is blocked by the inlet blocking portion 122a and the fuel gas enters the second space 126 through the fuel gas outlet communication hole 42 by the outlet blocking portion 122b. Is also avoided. As a result, the second space 126 functions as a heat insulating space because the flow of fuel gas is blocked by the blocking portions 122a and 122b.

As shown in FIG. 2, the cooling medium supplied to each cooling medium inlet communication hole 48 is introduced into the cooling medium flow path 52 between the first separator 32 and the third separator 38 of the power generation cells 12 adjacent to each other. To. Further, the cooling medium flow path 52 between the first separator 32 of the first end power generation cell 12a and the third dummy separator 130 of the intermediate dummy cell 16, and the third separator 38 and the second end of the second end power generation cell 12b. The cooling medium flow path 52 between the first dummy separator 105 of the partial dummy cell 20 and the cooling medium flow path between the first dummy separator 105 of the intermediate dummy cell 16 and the third dummy separator 130 of the first end dummy cell 18. Introduced in each of 52. That is, the first end power generation cell 12a and the second end power generation cell 12b (collectively referred to as the end power generation cell) and the dummy structures 15a and 15b adjacent to the end power generation cells 12a and 12b. A cooling medium flow path 52 is provided between them, and a cooling medium flows through the cooling medium flow path 52.

As shown in FIGS. 3 and 6, 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 approach each other. After flowing along the directions of arrows C1 and C2, it flows toward the arrow B2 side, and while cooling the electrolyte membrane / electrode structures 34a and 34b, it flows along the directions of arrows C1 and C2 so as to be separated from each other. Is distributed and discharged from each cooling medium outlet communication hole 50.

As described above, in the fuel cell stack 10 according to the present embodiment, cooling in which a cooling medium flows between the end power generation cells 12a and 12b and the dummy structures 15a and 15b adjacent to the end power generation cells 12a and 12b. A medium flow path 52 is provided. For example, when the fuel cell stack 10 is started (low temperature start) in a low temperature environment such as below freezing point, the temperature of the cooling medium becomes higher than that of the end power generation cells 12a and 12b due to power generation. By heating the cooling medium outside the fuel cell stack 10 with a heater or the like (not shown), the temperature of the cooling medium may be higher than the temperatures of the end power generation cells 12a and 12b. Therefore, by providing the cooling medium flow path 52 as described above and facilitating the heat transfer of the cooling medium flowing through the cooling medium flow path 52 to the end power generation cells 12a and 12b, the heat of the cooling medium flow path 52 can be easily transferred to the end power generation cells 12a and 12b in a low temperature environment. It is possible to quickly raise the temperature of the end power generation cells 12a and 12b. As a result, the low temperature startability of the fuel cell stack 10 can be improved.

Further, each of the dummy cells 16, 18 and 20 of the fuel cell stack 10 includes dummy conductors 106a and 106b instead of the electrolyte membrane / electrode structures 34a and 34b of the power generation cell 12. That is, since the dummy cells 16, 18 and 20 do not include the electrolyte membrane 84, the first electrode catalyst layer and the second electrode catalyst layer, they do not generate electricity and do not generate water generated by the power generation. As a result, the dummy cells 16, 18 and 20 themselves function as a heat insulating layer, and the formation of dew condensation on the dummy cells 16, 18 and 20 can be suppressed.

By laminating the dummy structures 15a and 15b having such dummy cells 16, 18 and 20 on at least one end side of the laminated body 14 in the laminating direction, the heat insulating property on the end side of the laminated body 14 is enhanced. Can be done. Therefore, it is possible to prevent the temperature on the end side of the laminate 14 from becoming lower than that on the center side, and even in a low temperature environment, the generated water or the like freezes on the end side of the laminate 14. It is possible to suppress the occurrence of voltage drop. As a result, the power generation stability of the fuel cell stack 10 can be improved.

Further, as described above, the dummy structures 15a and 15b enhance the heat insulating property on the end side of the laminated body 14, so that the entire temperature including the end portion of the laminated body 14 can be effectively raised. The low temperature startability can be improved. From the above, according to the fuel cell stack 10 according to the present embodiment, it is possible to improve the low temperature startability and the power generation stability.

The dummy structures 15a and 15b of the fuel cell stack 10 according to the above embodiment have end dummy cells 18 and 20 arranged at outer ends in the stacking direction, and the end dummy cells 18 and 20 are dummy conductors. It was decided that 106a and 106b were formed by being sandwiched between two dummy separators 105, 108 and 130. In this case, the end dummy cells 18 and 20 having a simple structure can enhance the heat insulating property on the end side of the laminated body 14.

The dummy structures 15a and 15b of the fuel cell stack 10 according to the above embodiment have intermediate dummy cells 16 arranged between the end power generation cells 12a and 12b and the end dummy cells 18 and 20, and the intermediate dummy cells 16 Has a first dummy conductor 106a, a second dummy conductor 106b, a first dummy separator 105, a second dummy separator 108, and a third dummy separator 130, and the first dummy separator 105 and the first dummy separator 105 It was decided that the dummy conductor 106a, the second dummy separator 108, the second dummy conductor 106b, and the third dummy separator 130 are laminated in this order.

Since such an intermediate dummy cell 16 has a laminated structure similar to that of the power generation cell 12, it can be easily manufactured, and moreover, it is provided with a plurality of dummy conductors 106a and 106b and dummy separators 105, 108 and 130. The heat insulating property on the end side of the laminated body 14 can be effectively enhanced.

In the fuel cell stack 10 according to the above embodiment, the dummy separator 108 disposed at the outer end portion of the end dummy cells 18 and 20 in the stacking direction is configured in the same manner as the second dummy separator 108. In this case, the cooling medium flow path 52 can be easily provided between the adjacent end power generation cells 12a and 12b or the intermediate dummy cell 16 while simplifying the manufacturing process of the end dummy cells 18 and 20.

In the fuel cell stack 10 according to the above embodiment, the cooling medium flow path 52 through which the cooling medium flows is provided between the end dummy cells 18 and 20 and the intermediate dummy cell 16. In this case, the heat of the cooling medium flowing through the cooling medium flow path 52 can quickly raise the temperature of the end power generation cells 12a and 12b even in a low temperature environment, and the end side of the laminated body 14 can be raised. It is possible to improve the heat insulating property of. Thereby, the low temperature startability and the power generation stability can be further improved.

In the fuel cell stack 10 according to the above embodiment, the dummy structures 15a and 15b are laminated on both ends of the laminated body 14 in the stacking direction, respectively. In this case, since the heat insulating property on both ends of the laminated body 14 can be improved, the low temperature startability and the power generation stability can be further effectively improved.

By the way, in the fuel cell stack 10, the oxidant gas in a humidified state is supplied to the oxidant gas inlet communication hole 40. When the water in the oxidant gas condenses to form liquid dew water, and the dew water jumps into the power generation cell 12, the diffusibility of the fuel gas and the oxidant gas may decrease.

In the fuel cell stack 10 according to the above embodiment, dummy cells 16, 18 and 20 are provided at the stacking direction ends of the laminated body 14, and the first dummy cells 16, 18 and 20 through which the oxidant gas flows. Space 109 is provided. Therefore, even if the oxidant gas contains dew condensation water, the dew condensation water can be collected by the dummy cells 16, 18 and 20, so that the dew condensation water jumps into the power generation cell 12. Can be suppressed. In particular, by disposing a larger number of dummy cells 16 and 18 on one end side (arrow A1 side) of the laminated body 14 to which the oxidizing agent gas is supplied than on the other end side (arrow A2 side), dew condensation occurs on the power generation cell 12. The ingress of water can be suppressed more effectively. As a result, it becomes possible to further improve the power generation stability of the fuel cell stack 10.

On the other hand, in the above embodiment, the dummy cells 16, 18 and 20 are provided with the second space 126 (insulation space) through which the fuel gas does not flow by the blocking portions 122a and 122b. The heat insulating property of 20 can be further improved, and 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 above-described embodiment, and various modifications can be made without departing from the gist thereof.

In the above embodiment, the dummy structure 15a includes the first end dummy cell 18 and the intermediate dummy cell 16, and the dummy structure 15b includes the second end dummy cell 20. However, it is not particularly limited to this. For example, in the fuel cell stack 10 according to the modified example, the dummy structures 15a and 15b include at least one dummy cell having the same configuration as the intermediate dummy cell 16 described above, and the first end dummy cell 18 and the second end portion described above. The dummy cell 20 may not be provided.

Further, the fuel cell stack 10 may be provided with dummy structures 15a and 15b on at least one end side of the laminated body 14 in the stacking direction, and the number of dummy cells 16, 18 and 20 included in each of the dummy structures 15a and 15b is particularly limited. It is not something that is done. Further, the number and configuration of the dummy conductors 106a and 106b and the dummy separators 105, 108 and 130 constituting the dummy cells 16, 18 and 20 are not particularly limited. The dummy cells 16, 18 and 20 may be configured so that the cooling medium flow path 52 can be formed between the dummy cells 16 and 18 and 20 and the adjacent power generation cells 12 without generating power.

10 ... Fuel cell stack 12 ... Power generation cell 12a, 12b ... End power generation cell 14 ... Laminated body 15a, 15b ... Dummy structure 16 ... Intermediate dummy cell 18 ... First end dummy cell 20 ... Second end dummy cell 32 ... First separator 34a ... 1st electrolyte membrane / electrode structure 34b ... 2nd electrolyte membrane / electrode structure 36 ... 2nd separator 38 ... 3rd separator 105 ... 1st dummy separator 106a ... 1st dummy conductor 106b ... 2nd dummy conductor 108 ... 2nd dummy separator 130 ... 3rd dummy separator

Claims (5)

A laminated body in which multiple power generation cells are laminated, and
A dummy structure laminated at at least one end in the stacking direction of the laminated body is provided.
Each of the power generation cells has a first electrolyte membrane / electrode structure, a second electrolyte membrane / electrode structure, a first separator, a second separator, and a third separator, and the first separator, the said. A fuel cell stack in which the first electrolyte membrane / electrode structure, the second separator, the second electrolyte membrane / electrode structure, and the third separator are laminated in this order.
The dummy structure has a dummy conductor corresponding to the electrolyte membrane / electrode structure and a dummy separator sandwiching the dummy conductor.
A cooling medium through which a cooling medium flows between an end power generation cell, which is a power generation cell, arranged at an end of the laminated body in the stacking direction and a dummy structure adjacent to the end power generation cell. A flow path is provided ,
The dummy structure has an end dummy cell arranged at the outer end in the stacking direction.
The end dummy cell is a fuel cell stack formed by sandwiching the dummy conductor between two dummy separators . In the fuel cell stack according to claim 1 .
The dummy structure has an intermediate dummy cell disposed between the end power generation cell and the end dummy cell.
The intermediate dummy cell has a first dummy conductor, a second dummy conductor, a first dummy separator, a second dummy separator, and a third dummy separator, and the first dummy separator and the first dummy separator. A fuel cell stack in which a conductor, the second dummy separator, the second dummy conductor, and the third dummy separator are laminated in this order. In the fuel cell stack according to claim 2 .
The dummy separator disposed at the outer end portion of the end dummy cell in the stacking direction is a fuel cell stack having the same configuration as the second dummy separator. In the fuel cell stack according to claim 2 or 3 .
A fuel cell stack in which the cooling medium flow path through which a cooling medium flows is provided between the end dummy cell and the intermediate dummy cell. In the fuel cell stack according to any one of claims 1 to 4 .
A fuel cell stack in which the dummy structure is laminated on both ends of the laminated body in the stacking direction.

Images