JP5591392B2 - Fuel cell electrolyte / electrode structure and fuel cell - Google Patents

Description

  The present invention relates to an electrolyte / electrode structure for a fuel cell in which a pair of electrodes are disposed on both sides of an electrolyte, and a fuel cell in which the electrolyte / electrode structure is sandwiched between a pair of separators.

  For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane (electrolyte) made of a polymer ion exchange membrane. In this fuel cell, an electrolyte membrane / electrode structure (electrolyte / electrode structure) in which an anode catalyst electrode and a cathode electrode made of porous carbon are disposed on both sides of a solid polymer electrolyte membrane, respectively. A unit cell is configured by being sandwiched by a separator (bipolar plate). Usually, a fuel cell stack in which a predetermined number of unit cells are stacked is used for in-vehicle use, for example.

  Generally, in the electrolyte membrane / electrode structure, the solid polymer electrolyte membrane has a larger surface area than the anode side electrode and the cathode side electrode, and the outer periphery of the solid polymer electrolyte membrane protrudes outward. Yes. However, the outer peripheral portion of the solid polymer electrolyte membrane has a problem that the mechanical strength is weak and the outer peripheral portion is easily damaged.

  Thus, for example, a solid polymer electrolyte membrane fuel cell disclosed in Patent Document 1 is known. As shown in FIG. 16, this fuel cell includes an electrolyte membrane / electrode structure 3 in which an anode 2 a and a cathode 2 b are laminated on both main surfaces of a solid polymer electrolyte membrane 1. The electrolyte membrane / electrode structure 3 is sandwiched between reaction gas supply plates 4a and 4b.

  The reaction gas supply plate 4a is provided with a fuel gas flow path 5a for supplying fuel gas to the anode 2a, while the reaction gas supply plate 4b is provided with an oxidant gas for supplying an oxidant gas to the cathode 2b. A flow path 5b is provided.

  Gas seal portions 6a and 6b are disposed between the electrolyte membrane / electrode structure 3 and the reaction gas supply plates 4a and 4b, and between the gas seal portions 6a and 6b and the solid polymer electrolyte membrane 1. Reinforcing films 7a and 7b are interposed between the two.

JP-A-5-2442897

  By the way, when a fuel cell stack is configured by stacking a plurality of the above fuel cells, reaction gas communication holes (not shown) penetrating in the stacking direction are formed in the outer peripheral edge portions of the reaction gas supply plates 4a and 4b. Yes. The fuel gas reactive gas communication hole communicates with the fuel gas flow channel 5a and supplies fuel gas to the fuel gas flow channel 5a, while the oxidant gas reactive gas communication hole communicates with the oxidant gas flow channel 5b. The oxidant gas is supplied to the oxidant gas flow path 5b. This is a so-called internal manifold structure.

  At that time, the fuel gas and the oxidant gas are generated between the reaction gas communication hole for the fuel gas and the fuel gas flow path 5a and between the reaction gas communication hole for the oxidant gas and the oxidant gas flow path 5b. In order to smoothly distribute and supply the surface, it is necessary to provide a buffer unit.

  However, in the above fuel cell, the gas seal portions 6a and 6b are disposed on the outer periphery of the solid polymer electrolyte membrane 1 with the reinforcing membranes 7a and 7b interposed therebetween, and the flow path cross section of the buffer portion is considerably It becomes narrower. As a result, the pressure loss due to the concentration of the reaction gas increases, and there is a problem that the reaction gas cannot be uniformly distributed in a sufficient amount on the power generation surface.

  The present invention solves this type of problem, and provides an electrolyte / electrode structure for a fuel cell and a fuel that can reinforce the electrolyte and distribute and supply sufficient reaction gas to the power generation surface with a compact configuration. An object is to provide a battery.

The present invention is to provided a pair of electrodes on both sides of the solid polymer electrolyte membrane is an electrolyte, the solid polymer electrolyte membrane has a larger surface area than the electrodes, projecting outwardly from the electrode The present invention relates to an electrolyte / electrode structure for a fuel cell in which a frame-shaped reinforcing portion is provided on at least one surface side of the outer peripheral portion.

In this electrolyte / electrode structure, a reaction gas passage is formed in the frame-shaped reinforcing portion for allowing a reaction gas, which is a fuel gas or an oxidant gas, to flow along the plane of the frame-shaped reinforcing portion.

  The reactive gas passage is preferably formed by joining a frame member having a passage shape to the frame-shaped reinforcing portion.

Furthermore, the present invention provides an electrolyte electrode assembly which is disposed a pair of electrodes on both sides of the solid polymer electrolyte membrane is an electrolyte, as well as sandwiched between a pair of separators, the solid polymer electrolyte membrane, from the electrode Further, the present invention relates to a fuel cell having a large surface area and having a frame-shaped reinforcing portion provided on at least one surface side of an outer peripheral portion protruding outward from the electrode.

Between the electrolyte / electrode structure and one separator, a reaction gas flow path for flowing a reaction gas, which is a fuel gas or an oxidant gas, along one electrode, and at least the reaction gas is supplied to one of the separators. A buffer portion that is circulated between the outside of the electrode and the reaction gas flow path is provided, and the frame-shaped reinforcing portion is disposed along a plane of the frame-shaped reinforcing portion at a portion corresponding to the buffer portion. A reaction gas passage for flowing the reaction gas is formed.

  Furthermore, it is preferable that a reaction gas channel portion is formed in one separator in a portion corresponding to the buffer portion so as to face the reaction gas passage.

  Moreover, it is preferable that the reaction gas flow path part is formed in the same shape as the reaction gas channel of the buffer part.

  In the electrolyte / electrode structure according to the present invention, since the frame-shaped reinforcing portion is provided on at least one surface side of the outer peripheral portion of the electrolyte, the electrolyte can be reinforced. Moreover, since the reaction gas passage is formed in the frame-shaped reinforcing portion, the thickness of the electrolyte / electrode structure itself does not increase, and the passage height of the reaction gas passage can be secured.

  Therefore, the fuel cell as a whole can be downsized, pressure loss in the reaction gas passage can be reduced, and drainage performance can be improved. Furthermore, the reaction gas can be uniformly distributed to the electrodes, and the power generation performance can be easily improved.

  In the fuel cell according to the present invention, the frame-shaped reinforcing portion is formed with a reaction gas passage for flowing the reaction gas to a portion corresponding to the buffer portion. For this reason, a sufficient cross-sectional area can be secured in the buffer part where the reaction gas flowing through the electrode reaction surface gathers, and the buffer part can be secured to the reaction gas flow path or from the reaction gas flow path to the buffer. It becomes possible to smoothly and reliably distribute and supply the reaction gas to the section.

1 is an exploded perspective view of a fuel cell according to a first embodiment of the present invention. FIG. 4 is a cross-sectional explanatory view of the fuel cell in which a plurality of unit cells are stacked. It is front explanatory drawing of the electrolyte and electrode structure which comprises the said unit cell. It is front explanatory drawing of the 1st metal separator which comprises the said unit cell. It is front explanatory drawing of the 2nd metal separator which comprises the said unit cell. It is a cross-sectional explanatory view of a fuel cell according to a second embodiment of the present invention. It is a section explanatory view of a fuel cell concerning a 3rd embodiment of the present invention. It is a disassembled perspective explanatory drawing of the fuel cell which concerns on the 4th Embodiment of this invention. FIG. 4 is a cross-sectional explanatory view of the fuel cell in which a plurality of unit cells are stacked. It is front explanatory drawing of the 1st metal separator which comprises the said unit cell. It is front explanatory drawing of the 2nd metal separator which comprises the said unit cell. It is front explanatory drawing of the electrolyte and electrode structure which comprises the said unit cell. It is a disassembled perspective explanatory drawing of the fuel cell which concerns on the 5th Embodiment of this invention. FIG. 4 is a cross-sectional explanatory view of the fuel cell in which a plurality of unit cells are stacked. It is front explanatory drawing of the 2nd carbon separator which comprises the said unit cell. 1 is a cross-sectional explanatory view of a solid polymer electrolyte membrane fuel cell disclosed in Patent Document 1. FIG.

  FIG. 1 is an exploded perspective view of a fuel cell 10 according to a first embodiment of the present invention, and FIG. 2 is a diagram illustrating the fuel cell 10 in which a plurality of unit cells 12 are stacked in the direction of arrow A and stacked. FIG.

  In the unit cell 12, the electrolyte membrane / electrode structure (electrolyte / electrode structure) 14 according to the first embodiment is sandwiched between a first metal separator 16 and a second metal separator 18. The first and second metal separators 16 and 18 are configured, for example, by pressing a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate having a metal surface subjected to anticorrosion surface treatment.

  One end edge of the unit cell 12 in the direction of arrow B (horizontal direction in FIG. 1) communicates with each other in the direction of arrow A, which is the stacking direction, and oxidant for supplying an oxidant gas, for example, an oxygen-containing gas An agent gas inlet communication hole 20a, a cooling medium inlet communication hole 22a for supplying a cooling medium, and a fuel gas outlet communication hole 24b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided in an arrow C direction (vertical direction). Are provided in an array.

  The other end edge of the unit cell 12 in the direction of the arrow B communicates with each other in the direction of the arrow A, the fuel gas inlet communication hole 24a for supplying the fuel gas, and the cooling medium outlet communication hole for discharging the cooling medium. 22b and an oxidant gas outlet communication hole 20b for discharging the oxidant gas are arranged in the direction of arrow C.

  The electrolyte membrane / electrode structure 14 includes, for example, a solid polymer electrolyte membrane 26 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 28 and an anode side electrode 30 that sandwich the solid polymer electrolyte membrane 26. With. The solid polymer electrolyte membrane 26 is set to have a larger surface area than the cathode side electrode 28 and the anode side electrode 30.

  The cathode side electrode 28 and the anode side electrode 30 are uniformly coated with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 26.

  On both sides of the outer peripheral edge of the solid polymer electrolyte membrane 26, a resin frame-like reinforcing portion (reinforcing membrane) 32 is integrally formed by, for example, injection molding, or a resin sheet is integrated by an adhesive. The As the resin material, engineering plastics, super engineering plastics (for example, PI, PPS), etc. are adopted in addition to general-purpose plastics. The reinforcing portion 32 is configured in a thin film shape than the cathode side electrode 28 and the anode side electrode 30 (see FIG. 2). The reinforcing part 32 may be provided only on one surface of the solid polymer electrolyte membrane 26.

  As shown in FIGS. 2 and 3, on the surface of the reinforcing portion 32 on the first metal separator 16 side, an oxidant gas for flowing an oxidant gas through a portion corresponding to an oxidant gas inlet buffer 44 a described later. An inlet passage 34a and an oxidant gas outlet passage 34b for flowing the oxidant gas are formed in a portion corresponding to an oxidant gas outlet buffer portion 44b described later.

  As shown in FIGS. 1 and 2, a fuel gas inlet passage 36a for flowing fuel gas through a portion corresponding to a fuel gas inlet buffer 50a described later is provided on the surface of the reinforcing portion 32 on the second metal separator 18 side. In addition, a fuel gas outlet passage 36b for flowing the fuel gas is formed in a portion corresponding to a fuel gas outlet buffer 50b described later.

  The oxidant gas inlet passage 34a and the oxidant gas outlet passage 34b are formed by frame members 38a and 38b having a desired passage shape and joined to the reinforcing portion 32. The frame members 38a and 38b are made of, for example, the same material as that of the reinforcing portion 32, and are fixed to the reinforcing portion 32 through a hot press in a state where an adhesive is applied in advance.

  Similarly, the fuel gas inlet passage 36 a and the fuel gas outlet passage 36 b are formed by frame members 40 a and 40 b having a desired passage shape and joined to the reinforcing portion 32. The frame members 40a and 40b are made of the same material as that of the reinforcing portion 32, and are fixed to the reinforcing portion 32 by hot pressing in a state where an adhesive is applied in advance. The thickness t1 between the frame members 38a and 40b (between the frame members 38b and 40a) is set to the same dimension as the thickness t2 of the electrolyte membrane / electrode structure 14 (t1 = t2). For this reason, the handleability of the electrolyte membrane / electrode structure 14 is improved, and the first and second metal separators 16 and 18 are easily pressed.

  The surface 16a of the first metal separator 16 facing the electrolyte membrane / electrode structure 14 is provided with a plurality of oxidant gas flow channel grooves 42 by forming the first metal separator 16 into a wave shape (uneven shape). It is done. The oxidant gas flow channel grooves 42 extend in parallel with each other in the direction of arrow B along the power generation surface of the cathode side electrode 28, and the oxidant gas flow channel 42 is disposed at both ends of the oxidant gas flow channel grooves 42. The part 42a and the oxidant gas outlet channel part 42b communicate with each other.

  Between the electrolyte membrane / electrode structure 14 and the first metal separator 16, an oxidant gas inlet passage 34 a and an oxidant gas inlet flow path part 42 a constitute an oxidant gas inlet buffer part 44 a, and an oxidation gas The oxidant gas outlet passage 34b and the oxidant gas outlet flow path part 42b constitute an oxidant gas outlet buffer part 44b.

  The oxidant gas inlet buffer unit 44a supplies the oxidant gas from the oxidant gas inlet communication hole 20a to the oxidant gas flow channel groove 42 in the power generation surface, while the oxidant gas outlet buffer unit 44b includes the oxidant gas. Used oxidant gas is discharged from the channel groove 42 to the oxidant gas outlet communication hole 20b.

  As shown in FIG. 4, a plurality of cooling medium flow channel grooves 46 are formed on the surface 16 b of the first metal separator 16 due to the back surface shape of the oxidant gas flow channel groove 42. At both ends of the cooling medium flow channel 46, a cooling medium inlet flow channel 46a that is the back surface shape of the oxidant gas inlet flow channel portion 42a and a cooling medium outlet flow that is the back surface shape of the oxidant gas outlet flow channel portion 42b. The road part 46b communicates.

  As shown in FIG. 5, a plurality of fuel gases are formed on the surface 18a of the second metal separator 18 facing the electrolyte membrane / electrode structure 14 by forming the second metal separator 18 into a wave shape (uneven shape). A channel groove 48 is provided. The fuel gas channel grooves 48 extend parallel to each other in the direction of arrow B along the power generation surface of the anode side electrode 30, and fuel gas inlet channels 48 a and The fuel gas outlet channel portion 48b communicates.

  Between the electrolyte membrane / electrode structure 14 and the second metal separator 18, a fuel gas inlet buffer 50 a for supplying fuel gas from the fuel gas inlet communication hole 24 a to the fuel gas flow channel groove 48 in the power generation surface; A fuel gas outlet buffer portion 50b for discharging used fuel gas from the fuel gas flow channel 48 to the fuel gas outlet communication hole 24b is provided.

  The fuel gas inlet buffer 50a is constituted by a fuel gas inlet passage 36a and a fuel gas inlet passage 48a, while the fuel gas outlet buffer 50b is composed of a fuel gas outlet passage 36b and a fuel gas outlet passage 48b. Consists of.

  As shown in FIG. 1, a plurality of cooling medium flow channel grooves 46 are formed on the surface 18 b of the second metal separator 18 due to the back surface shape of the fuel gas flow channel groove 48. At both ends of the cooling medium channel groove 46, a cooling medium inlet channel portion 46a that is the back surface shape of the fuel gas outlet channel portion 48b and a cooling medium outlet channel portion that is the back surface shape of the fuel gas inlet channel portion 48a. 46b communicates.

  As shown in FIGS. 1, 2, and 4, a first seal member 52 is provided on the outer peripheral edge portions of the surfaces 16 a and 16 b of the first metal separator 16. As shown in FIGS. 1, 2, and 5, a second seal member 54 is provided on the outer peripheral edge portions of the surfaces 18 a and 18 b of the second metal separator 18.

  The operation of the fuel cell 10 configured as described above will be described below.

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 20a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 24a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 22a.

  Therefore, the oxidant gas is introduced from the oxidant gas inlet communication hole 20a through the oxidant gas inlet buffer 44a of the first metal separator 16 into the oxidant gas flow channel 42. The oxidant gas moves in the direction of arrow B along the plurality of oxidant gas flow channel grooves 42 and is supplied to the cathode side electrode 28 of the electrolyte membrane / electrode structure 14.

  On the other hand, as shown in FIG. 5, the fuel gas is introduced from the fuel gas inlet communication hole 24 a through the fuel gas inlet buffer 50 a of the second metal separator 18 into the fuel gas flow channel groove 48. The fuel gas moves in the direction of arrow B along the plurality of fuel gas flow channel grooves 48 and is supplied to the anode side electrode 30 of the electrolyte membrane / electrode structure 14.

  Therefore, in each electrolyte membrane / electrode structure 14, the oxidant gas supplied to the cathode side electrode 28 and the fuel gas supplied to the anode side electrode 30 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed.

  The used oxidant gas passes through the oxidant gas outlet buffer 44b and is discharged to the oxidant gas outlet communication hole 20b. On the other hand, the spent fuel gas is discharged to the fuel gas outlet communication hole 24b through the fuel gas outlet buffer 50b.

  Further, the cooling medium is supplied from the cooling medium inlet communication hole 22 a to the cooling medium flow channel 46 formed between the first metal separator 16 and the second metal separator 18. The cooling medium cools the power generation surface of the electrolyte membrane / electrode structure 14 and then is discharged to the cooling medium outlet communication hole 22b.

  In this case, in the first embodiment, the solid polymer electrolyte membrane 26 constituting the electrolyte membrane / electrode structure 14 is reinforced on both sides of the outer peripheral edge portion protruding outward of the cathode side electrode 28 and the anode side electrode 30. The portion 32 is provided, and the solid polymer electrolyte membrane 26 can be reinforced well.

  In addition, as shown in FIGS. 2 and 3, the reinforcing portion 32 has an oxidant gas inlet passage 34a and an oxidant gas outlet passage 34b on the surface facing the first metal separator 16 via frame members 38a and 38b. Is formed. Therefore, the electrolyte membrane / electrode structure 14 does not have a large dimension in the thickness direction, and can secure the passage height (groove depth) of the oxidant gas inlet passage 34a and the oxidant gas outlet passage 34b. It becomes possible.

  At that time, the first metal separator 16 includes an oxidant gas inlet channel 42a having the same shape as the oxidant gas inlet channel 34a, and an oxidant gas outlet channel 42b having the same shape as the oxidant gas outlet channel 34b. Is formed.

  As a result, an oxidant gas inlet buffer portion 44a comprising the oxidant gas inlet passage 34a and the oxidant gas inlet passage portion 42a, and an oxidant comprising the oxidant gas outlet passage 34b and the oxidant gas outlet passage portion 42b. The gas outlet buffer 44b can set the flow path height to be large. Therefore, the size of the unit cells 12 in the stacking direction is not increased, the fuel cell 10 is reduced in size, and the pressure loss in the oxidant gas inlet buffer unit 44a and the oxidant gas outlet buffer unit 44b is reduced. It can be effectively reduced.

  Furthermore, it is possible to improve drainage in the oxidant gas inlet buffer 44a and the oxidant gas outlet buffer 44b, and the oxidant gas can be uniformly distributed to the cathode side electrode 28. There is an effect that the power generation performance can be easily improved.

  Similarly, frame members 40a and 40b are fixed to the reinforcing portion 32 to form a fuel gas inlet passage 36a and a fuel gas outlet passage 36b (see FIGS. 1 and 2). In the second metal separator 18, a fuel gas inlet channel portion 48 a is formed facing the fuel gas inlet passage 36 a, and a fuel gas outlet channel portion 48 b is formed facing the fuel gas outlet passage 36 b. The fuel gas inlet buffer 50a and the fuel gas outlet buffer 50b are respectively configured.

  Therefore, the flow path heights of the fuel gas inlet buffer 50a and the fuel gas outlet buffer 50b can be set large, and the thickness of the unit cell 12 does not increase. Accordingly, there is an advantage that the fuel cell 10 as a whole can be reduced in size, and the fuel gas can be uniformly distributed to the anode-side electrode 30 to improve the power generation performance.

  In the first embodiment, the oxidant gas inlet passage 34a and the oxidant gas inlet passage portion 42a are set to have the same shape, but may have different shapes. Further, in the oxidant gas outlet passage 34b and the oxidant gas outlet passage portion 42b, the fuel gas inlet passage 36a and the fuel gas inlet passage portion 48a, and the fuel gas outlet passage 36b and the fuel gas outlet passage portion 48b, It is the same.

  FIG. 6 is an explanatory cross-sectional view of a fuel cell 60 according to the second embodiment of the present invention. The same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third to fifth embodiments described below, detailed description thereof is omitted.

  The fuel cell 60 is configured by laminating a plurality of unit cells 62, and the unit cell 62 includes an electrolyte membrane / electrode structure 64 according to the second embodiment. A resin frame-shaped reinforcing portion 66 is integrally formed on both surfaces of the outer peripheral edge of the solid polymer electrolyte membrane 26 constituting the electrolyte membrane / electrode structure 64.

  The reinforcing portion 66 is provided with an oxidant gas inlet passage 34a and an oxidant gas outlet passage 34b by providing a notch on the surface on the first metal separator 16 side, and is cut on the surface on the second metal separator 18 side. By providing the notch, the fuel gas inlet passage 36a and the fuel gas outlet passage 36b are provided.

  In the second embodiment configured as described above, the reinforcing portions 66 are provided on both surfaces of the outer peripheral edge portion of the solid polymer electrolyte membrane 26, and the oxidizing gas inlet passage 34 a and the oxidizing gas outlet are provided in the reinforcing portions 66. A passage 34b, a fuel gas inlet passage 36a, and a fuel gas outlet passage 36b are integrally formed. Therefore, the dimension of the electrolyte membrane / electrode structure 64 in the thickness direction is not increased, the passage height is ensured and the drainage can be improved, and the like, as in the first embodiment. The effect is obtained.

  FIG. 7 is an explanatory cross-sectional view of a fuel cell 68 according to the third embodiment of the present invention.

  The fuel cell 68 is configured by laminating a plurality of unit cells 62a, and the unit cell 62a includes the electrolyte membrane / electrode structure 64a according to the third embodiment. A plurality of resin frame-shaped reinforcing portions 69 are integrally formed on both surfaces of the outer peripheral edge portion of the solid polymer electrolyte membrane 26 constituting the electrolyte membrane / electrode structure 64a.

  Each reinforcing portion 69 is provided corresponding to a portion between the first metal separator 16 and the second metal separator 18 that are close to each other. Between the reinforcing parts 69, the solid polymer electrolyte membrane 26 is directly exposed to the oxidant gas inlet buffer part 44a, the oxidant gas outlet buffer part 44b, the fuel gas inlet buffer part 50a, and the fuel gas outlet buffer part 50b.

  In the third embodiment configured as described above, the same effects as those of the first and second embodiments can be obtained.

  FIG. 8 is an exploded perspective view of a fuel cell 70 according to a fourth embodiment of the present invention, and FIG. 9 is a cross-sectional view of the fuel cell 70 in which a plurality of unit cells 72 are stacked.

  The unit cell 72 is configured by sandwiching an electrolyte membrane / electrode structure 74 according to the third embodiment between a first metal separator 76 and a second metal separator 78. A plurality of oxidant gas flow channel grooves 42 are provided on a surface 76 a of the first metal separator 76 facing the electrolyte membrane / electrode structure 74. An oxidant gas inlet buffer 80a and an oxidant gas outlet buffer 80b are formed at both ends of the oxidant gas flow channel 42 in the direction of arrow B. The oxidant gas inlet buffer unit 80a and the oxidant gas outlet buffer unit 80b have a plurality of embosses 82a and 82b.

  As shown in FIG. 10, a plurality of cooling medium flow channel grooves 46 are formed on the surface 76 b of the first metal separator 76. At both ends of the cooling medium passage groove 46, a cooling medium inlet buffer portion 84a that is the back surface shape of the oxidant gas inlet buffer portion 80a, and a cooling medium outlet buffer portion 84b that is the back surface shape of the oxidant gas outlet buffer portion 80b, Communicate.

  The cooling medium inlet buffer portion 84a and the cooling medium outlet buffer portion 84b have a plurality of embosses 86a and 86b, respectively.

  As shown in FIG. 11, a plurality of fuel gas flow channel grooves 48 are provided on a surface 78 a of the second metal separator 78 facing the electrolyte membrane / electrode structure 74. A fuel gas inlet buffer portion 88a and a fuel gas outlet buffer portion 88b communicate with both ends of the fuel gas passage groove 48. The fuel gas inlet buffer portion 88a and the fuel gas outlet buffer portion 88b have a plurality of embosses 90a and 90b, respectively.

  As shown in FIG. 8, a plurality of cooling medium flow channel grooves 46 are formed on the surface 78 b of the second metal separator 78. The cooling medium inlet buffer portion 84 a and the cooling medium outlet buffer portion 84 b communicate with both ends of the cooling medium flow channel 46.

  As shown in FIGS. 9 and 12, the reinforcing portions 32 are integrally formed on both surfaces of the outer peripheral edge of the solid polymer electrolyte membrane 26 constituting the electrolyte membrane / electrode structure 74. The reinforcing portion 32 is located outside both ends of the cathode side electrode 28 in the direction of arrow B, and oxidizes into a portion corresponding to the oxidant gas inlet buffer portion 80a and a portion corresponding to the oxidant gas outlet buffer portion 80b. An agent gas inlet passage 92a and an oxidant gas outlet passage 92b are formed.

  The oxidant gas inlet passage 92a is formed by an embossed shape portion of the frame member 94a joined to (or integrally formed with) the reinforcing portion 32, while the oxidant gas outlet passage 92b is joined to the reinforcing portion 32. Formed (or integrally formed) by the embossed shape portion of the frame member 94b.

  As shown in FIG. 8, the reinforcing portion 32 is located at both ends of the anode side electrode 30 in the direction of arrow B, and the fuel gas inlet buffer portion 88 a and the fuel gas outlet buffer portion 88 b are respectively provided with fuel. A gas inlet passage 96a and a fuel gas outlet passage 96b are formed.

  The fuel gas inlet passage 96a is formed by an embossed shape portion of a frame member 98a provided in the reinforcing portion 32, while the fuel gas outlet passage 96b is formed by an embossed shape portion of the frame member 98b provided in the reinforcing portion 32. The

In the fourth embodiment configured as described above, for example, the fuel gas inlet buffer portion 88 a and the fuel gas outlet buffer portion 88 b communicating with both ends of the fuel gas flow channel 48 are formed in the second metal separator 78. embossed scan 9 0a, it is configured 90b and, by a fuel gas inlet passage 96a and the fuel gas outlet passage 96b formed in the reinforcement portion 32 of the solid polymer electrolyte membrane 26.

  Therefore, the fuel gas inlet buffer portion 88a and the fuel gas outlet buffer portion 88b can set the passage height large without increasing the thickness of the unit cells 72 in the stacking direction. As a result, the fuel cell 70 can be reduced in size, the pressure loss in the fuel gas inlet buffer portion 88a and the fuel gas outlet buffer portion 88b can be reduced, and drainage can be improved. The same effects as those of the first and second embodiments can be obtained.

  FIG. 13 is an exploded perspective view of a fuel cell 100 according to a fifth embodiment of the present invention, and FIG. 14 is an explanatory cross-sectional view of the fuel cell 100 in which a plurality of unit cells 102 are stacked to form a stack. is there.

  The unit cell 102 is configured by sandwiching an electrolyte membrane / electrode structure 14 between a first carbon separator 106 and a second carbon separator 108. A plurality of oxidant gas channel grooves 42 are provided on the surface 106 a of the first carbon separator 106 facing the electrolyte membrane / electrode structure 14. At the opposite ends of the oxidant gas flow channel groove 42 in the direction of arrow B, the oxidant gas inlet flow channel 42a constituting the oxidant gas inlet buffer 44a and the oxidant gas outlet flow constituting the oxidant gas outlet buffer 44b. The road part 42b communicates.

  The surface 106b of the first carbon separator 106 is configured to be flat, for example. As shown in FIG. 15, a plurality of fuel gas channel grooves 48 are provided on the surface 108 a of the second carbon separator 108 facing the electrolyte membrane / electrode structure 14. A fuel gas inlet channel portion 48a constituting the fuel gas inlet buffer portion 50a and a fuel gas outlet channel portion 48b constituting the fuel gas outlet buffer portion 50b communicate with both ends of the fuel gas passage groove 48.

  As shown in FIG. 13, a plurality of cooling medium passage grooves 46 are formed on the surface 108 b of the second carbon separator 108. At both ends of the cooling medium channel groove 46, a cooling medium inlet channel portion 46a communicating with the cooling medium inlet communication hole 22a and a cooling medium outlet channel portion 46b communicating with the cooling medium outlet communication hole 22b communicate.

  In the fifth embodiment configured as described above, the first carbon separator 106 and the second carbon separator 108 are used in place of the metal separator, and the electrolyte membrane / electrode structure 14 is provided. Accordingly, the overall size of the fuel cell 100 can be reduced, and the oxidant gas and the fuel gas can be uniformly distributed to the cathode side electrode 28 and the anode side electrode 30, respectively. The same effect as the embodiment can be obtained. Moreover, optimum shapes can be set individually for the reaction gas surface and the cooling medium surface.

  In the fifth embodiment, the electrolyte membrane / electrode structure 14 is used. Alternatively, the electrolyte membrane / electrode structure 64, 64a, or 74 can be used.

10, 60, 68, 70, 100 ... fuel cell 12 ... unit cell 14, 64, 64a, 74 ... electrolyte membrane / electrode structure 16, 18, 76, 78 ... metal separator 20a ... oxidant gas inlet communication hole 20b ... Oxidant gas outlet communication hole 22a ... cooling medium inlet communication hole 22b ... cooling medium outlet communication hole 24a ... fuel gas inlet communication hole 24b ... fuel gas outlet communication hole 26 ... solid polymer electrolyte membrane 28 ... cathode side electrode 30 ... anode side Electrodes 32, 66, 69 ... Reinforcing portions 34a, 92a ... Oxidant gas inlet passages 34b, 92b ... Oxidant gas outlet passages 36a, 96a ... Fuel gas inlet passages 36b, 96b ... Fuel gas outlet passages 38a, 38b, 40a, 40b , 94a, 94b, 98a, 98b ... Frame member 42 ... Oxidant gas channel groove 42a ... Oxidant gas inlet channel part 42b ... Oxidant gas outlet Path portions 44a, 80a ... Oxidant gas inlet buffer portions 44b, 80b ... Oxidant gas outlet buffer portion 46 ... Cooling medium flow channel groove 48 ... Fuel gas flow channel groove 48a ... Fuel gas inlet flow channel portion 48b ... Fuel gas outlet flow Path portions 50a, 88a ... Fuel gas inlet buffer portions 50b, 88b ... Fuel gas outlet buffer portions 62, 62a, 72, 102 ... Unit cell 84a ... Cooling medium inlet buffer portion 84b ... Cooling medium outlet buffer portion 106, 108 ... Carbon separator

Claims (6)

With arranging a pair of electrodes on both sides of the solid polymer electrolyte membrane is an electrolyte, the solid polymer electrolyte membrane has a larger surface area than the electrodes, at least the outer peripheral portion projecting outwardly from the electrode A fuel cell electrolyte / electrode structure provided with a frame-shaped reinforcing portion on one surface side,
An electrolyte electrode for a fuel cell, characterized in that a reaction gas passage is formed in the frame-shaped reinforcing portion for allowing a reaction gas, which is a fuel gas or an oxidant gas, to flow along the plane of the frame-shaped reinforcing portion. Structure. The electrolyte / electrode structure according to claim 1, wherein the reaction gas passage is formed by joining a frame member having a passage shape to the frame-shaped reinforcing portion. Electrode structure. An electrolyte / electrode structure having a pair of electrodes disposed on both sides of a solid polymer electrolyte membrane , which is an electrolyte , is sandwiched between a pair of separators, and the solid polymer electrolyte membrane has a larger surface area than the electrodes. A fuel cell in which a frame-shaped reinforcing portion is provided on at least one surface side of the outer peripheral portion protruding outward from the electrode,
Between the electrolyte / electrode structure and one of the separators, a reaction gas flow path for flowing a reaction gas that is a fuel gas or an oxidant gas along one of the electrodes;
A buffer portion for allowing at least the reaction gas to flow between the outside of the one electrode and the reaction gas flow path;
Is provided,
The fuel cell according to claim 1, wherein a reaction gas passage for allowing the reaction gas to flow along a plane of the frame-shaped reinforcing portion is formed in a portion corresponding to the buffer portion in the frame-shaped reinforcing portion.   4. The fuel cell according to claim 3, wherein the reactive gas passage is formed by overlapping a frame member having a passage shape on the frame-shaped reinforcing portion.   5. The fuel cell according to claim 3, wherein one of the separators is formed with a reaction gas flow path portion facing the reaction gas passage at a portion corresponding to the buffer portion. .   6. The fuel cell according to claim 5, wherein the reaction gas flow path portion is formed in the same shape as the reaction gas passage of the buffer portion.

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