JP2007305325A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve both short circuit prevention and rectifying effect in a fuel cell provided with a metallic separator and a metallic support frame. <P>SOLUTION: In the fuel cell FC, the respective protruding parts 61 and respective dented parts 51 are mutually separated and arranged both in the parallel direction and a perpendicular direction to faces of the metallic support frame 50 and the metallic separators 60a, 60b. That is, thickness of a seal member 10 is made to be the thickness that a prescribed gap is formed between the tip part of the respective protruding parts 61 and the bottom face of the respective dented parts 51. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell composed of single cells or a fuel cell in which a plurality of single cells are stacked.

  2. Description of the Related Art Fuel cell systems that use inorganic oxide as an electrolyte and operate at a relatively high operating temperature, for example, solid oxide fuel cells (SOFC) and hydrogen permeable membrane fuel cells (HMFC) are known. From the viewpoint of power generation efficiency, a thin electrolyte is desired, but inorganic oxides generally have brittle characteristics. Therefore, in a fuel cell system using a thin inorganic oxide as an electrolyte, it is preferable to include a support frame for supporting and reinforcing the electrolyte.

  For example, in a hydrogen separation membrane fuel cell including a membrane electrode assembly in which a hydrogen permeable metal layer is formed on one surface of a solid electrolyte and a cathode electrode is formed on the other surface, a membrane is used to reinforce the membrane electrode assembly. A support frame that supports the outer edge of the electrode assembly is used (see, for example, Patent Document 1).

JP 2005-243427 A

  However, in a fuel cell system operated at a high operating temperature, the support frame is also required to have heat resistance. Carbon materials become brittle when used at high operating temperatures, and the strength against fastening load when stacking single cells is insufficient. Ceramic materials are excellent in heat resistance, but sufficient for fastening load when stacking single cells. There is a problem of not having strength. Therefore, a metal support frame tends to be used as the support frame.

  In addition, the metal separator or the support frame is used to introduce a reaction gas from the reaction gas supply manifold to the membrane electrode assembly, or from the membrane electrode assembly to the reaction gas discharge manifold. A rectifying fin for guiding gas is formed or provided. Generally, a support frame including a membrane electrode assembly is sandwiched between metal separators via a gasket.

  Therefore, for example, when conductive rectifying fins are formed on a metal support frame and the height of the rectifying fins is high, a short circuit occurs between the metal separator and the metal support frame. There was a problem that it occurred. On the other hand, if the height of the rectifying fins is lowered to avoid a short circuit, there is a problem that a sufficient rectifying effect cannot be obtained.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to achieve both prevention of a short circuit and a rectifying effect in a fuel cell including a metal separator and a metal support frame.

  In order to solve the above problems, a first aspect of the present invention provides a fuel cell. A fuel cell according to a first aspect of the present invention is a metal electrode having a membrane electrode assembly and a plate-like metal support frame that supports an outer edge of the membrane electrode assembly, and having one or a plurality of indentations. A support frame; a pair of metal separators disposed on both sides of the metal support frame, the metal separator having one or more projecting portions corresponding to the respective indentations; and the metal support frame A reaction gas internal flow path formed by the metal separator and the pair of metal separators, and an insulating seal member disposed between the metal support frame and the pair of metal separators. The separation distance between the separator and the metal support frame is such that the pressure loss of the flow path formed by the protrusions and the recesses is higher than the pressure loss of the reaction gas internal flow path. And an insulating sealing member defining the distance which the the bottom of the tip and the respective recess of the protruding portion is separated.

  According to the fuel cell of the first aspect of the present invention, the distance between each metal separator and the metal support frame is equal to or less than the length of each protrusion, and the tip of each protrusion and each recess. Since the bottom part of the part is separated, a short circuit between the metal support frame and the pair of metal separators can be prevented, and a sufficient rectifying effect can be obtained.

  A second aspect of the present invention provides a fuel cell. The fuel cell according to the second aspect of the present invention includes a pair of metal separators having one or a plurality of indentations, a membrane electrode assembly, and a plate-like metal support that supports the outer edge of the membrane electrode assembly. A metal support frame having one or a plurality of protrusions corresponding to each of the recesses, the metal support frame and the pair of metal separators being disposed on both surfaces of the pair of metal separators A reactive gas internal flow path formed by a metal separator, and an insulating seal member disposed between the metal support frame and the pair of metal separators, each of the metal separator and the metal The separation distance from the manufactured support frame is such that the pressure loss of the flow path formed by each of the protrusions and the recesses is higher than the pressure loss of the reaction gas internal flow path. Comprising a tip with an insulating sealing member, wherein the prescribed distance of the bottom of each recess is separated.

  According to the fuel cell of the second aspect of the present invention, the separation distance between each metal separator and the metal support frame is equal to or less than the length of each protrusion, and the tip of each protrusion and each recess. Since the bottom part of the part is separated, a short circuit between the metal support frame and the pair of metal separators can be prevented, and a sufficient rectifying effect can be obtained.

  In the fuel cell according to the first or second aspect of the present invention, the seal member includes a tip portion of each protrusion in the same plane as the opening surface of each recess or included in each recess. By defining the separation distance as described above, the pressure loss of the flow path formed by the protrusions and the recesses may be higher than the pressure loss of the reaction gas internal flow path. In order to flow in the flow path formed by each protrusion and each dent, the tip of each protrusion is included in the same plane as the opening surface of each dent or included in each dent. The direction is changed, and the pressure loss increases.

  In the fuel cell according to the first or second aspect of the present invention, the pair of metal separators further includes a reaction gas supply unit for supplying a reaction gas to the membrane electrode assembly, The protruding portion may be a rectification unit that is formed between the reaction gas supply unit and the membrane electrode assembly and rectifies the reaction gas supplied from the reaction gas supply unit to the membrane electrode assembly. . In this configuration, it is possible to supply the reaction gas that has undergone desired rectification from the reaction gas supply unit to the membrane electrode assembly by each protrusion.

  In the fuel cell according to the first or second aspect of the present invention, the pair of metal separators further includes a reaction gas discharge part for discharging a reaction gas from the membrane electrode assembly, and each protrusion May be a rectification unit that is formed between the membrane electrode assembly and the reaction gas discharge unit and rectifies the reaction gas discharged from the membrane electrode assembly to the reaction gas discharge unit. In this configuration, the reaction gas subjected to desired rectification can be discharged from the membrane electrode assembly to the reaction gas discharge portion by each protrusion.

  In the fuel cell according to the first or second aspect of the present invention, the membrane electrode assembly may be a hydrogen separation membrane type membrane electrode assembly. By providing this configuration, the operating temperature required for the operation of the fuel cell can be lowered.

  In the fuel cell according to the first or second aspect of the present invention, each protrusion and each recess may have a rectangular cross section. By providing this configuration, the rectifying effect of the reaction gas can be improved.

  In the fuel cell according to the first or second aspect of the present invention, a diffusion layer may be disposed between the membrane electrode assembly and each metal separator. By providing this configuration, the diffusibility of the reaction gas can be improved.

  Hereinafter, a fuel cell according to the present invention will be described based on examples with reference to the drawings.

Configuration of Fuel Cell System A fuel cell system FCS that is commonly used in the following embodiments will be described with reference to FIGS. FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system used in this embodiment. FIG. 2 is an explanatory view showing a part of a cut surface of the fuel cell in FIG. 1 cut along a cutting line XX. FIG. 3 is an explanatory view showing the anode side of the metal support frame used in this embodiment. FIG. 4 is an explanatory view showing the cathode side of the metal support frame used in this embodiment. FIG. 5 is an explanatory view showing the surface of the anode-side metal separator used in this embodiment that faces the metal support frame.

  The fuel cell system FCS according to the present embodiment includes a fuel cell FC formed of a stacked body in which a plurality of single cells 100 are stacked, and reforming as a fuel gas supply source that supplies hydrogen gas as a fuel gas to the fuel cell FC. Device FR. By using the reformer FR as a fuel gas supply source, a fuel gas having a temperature equivalent to the operating temperature range of the fuel cell FC can be input to the fuel cell FC. The fuel cell FC includes a fuel gas (anode gas) supply unit 25a, an oxidizing gas (cathode gas) supply unit 26a, a refrigerant supply unit 27a, a fuel gas discharge unit 25b, an oxidation gas discharge unit 26b, and a refrigerant discharge unit 27b. .

  The fuel gas supply unit 25a of the fuel cell FC and the reformer FR are connected via a fuel gas supply pipe 200. In the vicinity of the reformer FR of the fuel gas supply pipe 200, a pressure regulating valve V1 for adjusting the fuel gas pressure supplied to the fuel cell FC to a predetermined pressure is disposed. For example, pure hydrogen or a hydrogen-containing gas (hydrogen-rich gas) is used as the fuel gas, and air (atmosphere) is used as the oxidizing gas.

  A fuel gas discharge pipe 201 is connected to the fuel gas discharge portion 25b. In the present embodiment, the fuel gas discharge pipe 201 is branched into a discharge branch pipe 201 a communicating with the atmosphere and a circulation branch pipe 201 b connected to the fuel gas supply pipe 200. A valve V2 is disposed in the discharge branch pipe 201a. When the valve V2 is closed, the fuel off-gas discharged from the fuel gas discharge unit 25b is supplied again into the fuel cell FC. On the other hand, when the valve V2 is opened, the fuel off-gas discharged from the fuel gas discharge unit 25b is discharged into the atmosphere. In general, the composition of the fuel off gas when the valve V2 is opened is mostly nitrogen and water vapor.

  The fuel gas supplied from the fuel gas supply unit 25a into the fuel cell FC passes through the fuel gas supply manifold 20a formed by the support frame 50, the separators 60a and 60b, and the seal member 10 to the anode of the electrolyte membrane. Supplied. The fuel gas consumed in the electrolyte membrane is discharged from the fuel gas discharge portion 25b to the fuel gas discharge pipe 201 via the fuel gas discharge manifold 20b formed by the support frame 50, the separators 60a and 60b, and the seal member 10. The

  An oxidizing gas (generally air) supplied from the oxidizing gas supply unit 26a into the fuel cell FC by an oxidizing gas supply pump (not shown) is formed by the support frame 50, the separators 60a and 60b, and the seal member 10. Is supplied to the cathode of the electrolyte membrane via the oxidizing gas supply manifold 21a. The oxidizing gas subjected to the electromotive reaction in the electrolyte membrane passes from the oxidizing gas discharge part 26b to the outside of the fuel cell FC via the oxidizing gas discharge manifold 21b formed by the support frame 50, the separators 60a and 60b, and the seal member 10. Is discharged.

  The refrigerant (generally pure water) supplied from the refrigerant supply unit 27a to the inside of the fuel cell FC passes through the refrigerant supply manifold 22a formed by the support frame 50, the separators 60a and 60b, and the seal member 10. It is supplied to the refrigerant flow path formed on the back surfaces (the surfaces not facing the electrolyte membrane) of the separators 60a and 60b. The refrigerant that is supplied to the refrigerant flow path and absorbs a part of the heat generated by the electromotive reaction is discharged through the refrigerant discharge manifold 22b formed by the support frame 50, the separators 60a and 60b, and the seal member 10. It guide | induces to the heat radiator which is not shown in figure from the part 27b. The refrigerant guided to the radiator is repeatedly supplied to the refrigerant supply unit 27a by the circulation pump.

  With reference to FIG. 2, the internal structure of the unit cell 100 constituting the fuel cell FC will be briefly described. The unit cell 100 includes a metal support frame 50 disposed between the pair of metal separators 60a and 60b and the pair of metal separators 60a and 60b as a fuel cell constituent member.

  The metal separators 60a and 60b are gas-impermeable and conductive plates used to separate the fuel gas and the oxidizing gas. A plurality of refrigerant flow paths 62a and 62b for allowing the refrigerant to flow are formed on the back surfaces of the separators 60a and 60b, that is, on the contact surfaces between the separators 60a and 60b. Each separator 60a, 60b is formed from, for example, a stainless steel material having excellent corrosion resistance.

  The metal support frame 50 is a metal frame for supporting a non-self-supporting membrane electrode assembly (MEA) 30, and in this embodiment, supports the membrane electrode assembly 30 over the entire anode side. A grid-like portion 56 is provided. The grid portion 56 includes a plurality of holes 561 for guiding the fuel gas to the membrane electrode assembly 30. The metal support frame 50 is made of, for example, a stainless steel material having excellent corrosion resistance. The metal support frame 50 and the membrane electrode assembly 30 are joined to each other by, for example, a known cladding method or laser welding.

  The membrane electrode assembly 30 used in the present embodiment is a hydrogen permeable membrane type membrane electrode assembly. The membrane electrode assembly 30 includes an electrolyte layer 31, a hydrogen permeable membrane layer 32, and a cathode 33.

The electrolyte layer 31 is formed of a solid electrolyte having proton conductivity. In the present embodiment, the electrolyte layer 31 is formed of a perovskite solid oxide such as BaCe _0.8 Y _0.2 O ₃ or SrZr _0.8 In _0.2 O ₃ . Since the electrolyte layer 31 is formed on the dense hydrogen permeable membrane layer 32, it is possible to reduce the thickness sufficiently. Thus, since the membrane resistance of the electrolyte layer 21 can be reduced by forming the electrolyte layer 21 thinner, the temperature is lower than the operating temperature of the conventional solid oxide fuel cell, for example, 400 ° C. to 600 ° C. The fuel cell can be operated.

  The hydrogen permeable membrane layer 32 is a layer formed of a metal having hydrogen permeability, and is formed of palladium (Pd) in this embodiment. In addition to the property of allowing hydrogen to permeate, palladium has an activity of dissociating hydrogen molecules when hydrogen permeates. The hydrogen permeable membrane layer 32 further functions as an anode in the fuel cell FC.

  The cathode 34 is a metal layer formed on the electrolyte layer 32 and is formed of a noble metal having catalytic activity that promotes an electrochemical reaction. In this embodiment, the cathode 24 is made of palladium. When the cathode 34 is composed of other kinds of noble metals that do not have hydrogen permeability, such as platinum (Pt), the cathode 34 is formed between the outer side of the cathode 34 (separator 60a side) and the electrolyte layer 31 by forming it sufficiently thin. What is necessary is just to ensure gas permeability in between.

  In the present embodiment, the gas diffusion property is given to the fuel gas internal flow path 37a formed by the grid portion 56 of the support frame 50 and the separator 60b, and the oxidizing gas internal flow path 37c formed by the cathode 34 and the separator 60a. In order to improve, an anode side gas diffusion layer 38a and a cathode side gas diffusion layer 38c are provided. Each gas diffusion layer 38a, 38c is a porous layer, and is constituted by a member having conductivity and gas permeability. As each gas diffusion layer 38a, 38c, for example, a metal porous body such as foam metal or metal mesh, or a carbon porous body such as carbon paper can be used.

  Between the metal support frame 50 and the metal separators 60a and 60b, a fuel cell seal member 10 for stopping the fuel gas and the oxidizing gas inside the unit cell 100 is disposed. The fuel cell seal member 10 is made of a material excellent in heat resistance, sealability, and insulation, for example, an inorganic material.

  The fuel gas supplied to the fuel gas supply manifold 25a shown in FIG. 1 is supplied to the anode side of the membrane electrode assembly 30 via the anode side gas diffusion layer 38a. The oxidizing gas supplied to the oxidizing gas supply manifold 26a is supplied to the cathode side of the membrane electrode assembly 30 through the cathode side gas diffusion layer 38c.

  The metal support frame 50 will be described with reference to FIGS. First, a configuration common to the anode surface (FIG. 3) and the cathode surface (FIG. 4) of the metal support frame 50 will be described below. The metal support frame 50, together with the separators 60a and 60b and the seal member 10 when stacked, has a fuel gas supply manifold forming portion 520a that forms the fuel gas supply manifold 25a, and a fuel gas discharge manifold forming portion 520b that forms the fuel gas discharge manifold 25b. It has. Similarly, the metal support frame 50 includes an oxidizing gas supply manifold forming portion 521a that forms the oxidizing gas supply manifold 26a, and an oxidizing gas discharge manifold forming portion 521b that forms the oxidizing gas discharge manifold 26b. The metal support frame 50 further includes a refrigerant supply manifold forming portion 522a that forms the refrigerant supply manifold 27a when stacked, and a refrigerant discharge manifold forming portion 522b that forms the refrigerant discharge manifold 27b.

  On both sides of the anode surface and the cathode surface of the metal support frame 50, metal separators 60a and 60b are provided to rectify each reaction gas flowing in the fuel gas internal channel 37a and the oxidizing gas internal channel 37c in a desired direction. A plurality of indentations 51 for receiving the tip of the formed projecting portion (also referred to as a rectifying portion) 61 are formed. The dent 51 is formed on the metal support frame 50 by, for example, cutting or etching. The relationship between the projecting portion 61 and the recessed portion 51 will be described later.

  On the anode surface of the metal support frame 50, as described above, the lattice-like portion 56 that supports the membrane electrode assembly 30 from the bottom surface on the anode side is provided. The lattice-like portion 56 may be formed by punching when the metal support frame 50 is manufactured, or an opening corresponding to the metal support frame 50 is formed, and a plurality of holes such as punching metal and expanded metal, Alternatively, it may be provided by joining another member having a slit. Since the metal support frame 50 only needs to support at least the outer edge of the membrane electrode assembly 30, the opening having a flange portion for receiving the outer edge of the membrane electrode assembly 30 without providing the lattice-like portion 56. You may have only. In this case, the area of the opening viewed from the cathode surface of the metal support frame 50 is substantially the same as the area of the membrane electrode assembly 30, and the opening area of the anode surface is the opening of the cathode surface by the area of the flange portion. Smaller than part area.

  The metal separator 60b used in the present embodiment will be described with reference to FIG. The metal separator 60b is, together with the metal support frame 50 and the seal member 10 when stacked, a fuel gas supply manifold forming portion 620a that forms the fuel gas supply manifold 25a, and a fuel gas discharge manifold forming portion 620b that forms the fuel gas discharge manifold 25b. It has. Similarly, the metallic separator 60b includes an oxidizing gas supply manifold forming portion 621a that forms the oxidizing gas supply manifold 26a, and an oxidizing gas discharge manifold forming portion 621b that forms the oxidizing gas discharge manifold 26b. The metal separator 60b further includes a refrigerant supply manifold forming portion 622a that forms the refrigerant supply manifold 27a when stacked, and a refrigerant discharge manifold forming portion 622b that forms the refrigerant discharge manifold 27b.

  A plurality of protrusions 61 for rectifying each reaction gas flowing in the fuel gas internal flow path 37a and the oxidation gas internal flow path 37c in a desired direction are provided on the surface of the metal separator 60b facing the metal support frame 50. Is formed. The protruding portion 61 is formed on the metal separator 60b by, for example, cutting, etching, or pressing.

  Here, the anode-side metal separator 60b has been described as an example, but the cathode-side separator 60a is similarly formed with a plurality of manifold forming portions and a plurality of protruding portions 61.

Configuration of the projecting portion 61 and the recessed portion 51:
The configuration of the protrusion 61 and the recess 51 will be described in detail with reference to FIGS. FIG. 6 is a plan view of the unit cell as viewed from the anode side. For the sake of explanation, the structure formed on the metal support frame and the components disposed between the metal support frame and the metal separator are shown. It is indicated by a dotted line. 7 is a cross-sectional view showing a cross section of the unit cell taken along the line YY in FIG. FIG. 8 is an explanatory diagram showing an enlarged view of the projecting portion and the recessed portion in FIG.

  Since FIG. 6 shows the anode surface of the metal support frame 50, the seal member 10 is not disposed in the fuel gas supply manifold forming portion 520a and the fuel gas discharge manifold forming portion 520b. Therefore, the fuel gas supplied from the fuel gas supply manifold forming part 520a to the fuel gas internal flow path 37a is rectified by the plurality of rectifying parts 61 and guided to the fuel gas discharge manifold forming part 520b as indicated by arrows. It is burned.

  In addition, the rectification direction of the fuel gas shown in FIG. 6 is an example, and is appropriately changed according to conditions. For example, the rectifying unit 61 may be arranged so that the fuel gas and the oxidizing gas flow in parallel to the longitudinal direction of the metal support frame 50. That is, the arrangement pattern of the rectifying unit 61 is appropriately arranged depending on how the fuel gas is allowed to flow.

  Although the cathode surface of the metal support frame 50 is not shown, the seal member 10 is not disposed on the oxidizing gas supply manifold forming portion 521a and the oxidizing gas discharge manifold forming portion 521b in the metal support frame 50. Therefore, the oxidizing gas supplied from the oxidizing gas supply manifold forming part 521a to the oxidizing gas internal flow path 37c is rectified by the plurality of rectifying parts 61 and guided to the oxidizing gas discharge manifold forming part 521b.

  As is clear from FIG. 6, the outer wall of the tip of each protrusion 61 received in each recess 51 is separated from the inner wall of each recess 51, and each protrusion 61 and each recess There is no electrical contact with 51. The positional relationship between each protrusion 61 and each recess 51 will be described with reference to FIGS.

  As shown in FIGS. 7 and 8, the protrusions 61 and the recesses 51 are not only in the direction parallel to the surfaces of the metal support frame 50 and the metal separators 60a and 60b but also in the vertical direction. They are spaced apart. That is, the thickness (height) of the seal member 10 is set such that a predetermined gap is formed between the distal end portion of each protruding portion 61 and the bottom surface of each indented portion 51.

  The rectifying unit rectifies the flow of the fluid by restricting the flow direction of the fluid to a direction along the rectifying unit (a direction substantially parallel to the rectifying unit). However, if the tip of the rectifying unit and the support frame are separated from each other, the fluid straddles (passes through) the tip of the rectifying unit, that is, the fluid flows in a direction crossing the rectifying unit. The rectifying effect of the period cannot be obtained. Therefore, in general, in order to obtain a rectifying effect by the rectifying unit, the height of the rectifying unit is preferably high. That is, when the rectification | straightening part is formed in the separator, it is preferable that the front-end | tip part of a rectification | straightening part and a support frame are adjoining.

  On the other hand, when the support frame and the separator are made of a conductive material, a short circuit occurs between the support frame and the separator due to contact between the tip of the rectifying unit and the support frame. In a fuel cell, since a fastening load is applied in the stacking direction, if the stacking direction and the extending direction of the tip of the rectifying unit match, the tip of the rectifying unit and the support frame are required to be separated to some extent. Is done. As a result, the rectification effect is reduced.

  On the other hand, in the fuel cell FC according to the present embodiment, both the insulation and the rectifying effect are achieved by adopting a configuration in which the tip of each protruding portion 61 as the rectifying portion is disposed in each of the recessed portions 51. ing. In the present embodiment, since the tip of the projecting portion 61 is disposed in the recessed portion 51, the direction of the flow is necessary for the slip flow indicated by the arrow F1 in FIGS. 7 and 8 to straddle the projecting portion 61. It must be changed approximately 90 degrees, ie from horizontal to vertical. Generally, the change in the flow direction becomes resistance, and the fluid has a characteristic of flowing in a portion having a low resistance, so that the flow in the changed direction is suppressed or eliminated. Furthermore, in this embodiment, the separation distance between the outer wall of the projecting portion 61 and the inner wall of the dent portion 51 is short, and the pressure loss (flow channel resistance) of the flow channel 511 formed by both 61 and 51 Compared with the flow path 37a or the oxidizing gas internal flow path 37c, it becomes extremely large. In the present embodiment, the ratio between the pressure loss of the flow path 511 and the pressure loss of the reaction gas internal flow paths 37a and 37c is, for example, 10: 1.

  As a result, the direction of the flow of the slip flow F1 is changed to the direction indicated by the arrow F2, and the flow straddling the protruding portion 61 can be suppressed or eliminated. Further, the flow straddling the projecting portion 61 is suppressed or prevented by the change of the flow direction and the large pressure loss of the flow path 511, so that the tip portion of the projecting portion 61 and the bottom portion of the dent portion 51 are separated from each other. The distance can be relatively large. Therefore, if the separation distance is set in consideration of the fastening load applied at the time of lamination, electrical contact between the metal support frame 50 and the metal separators 60a and 60b can be prevented. When the cells 100 are stacked, there is almost no movement or displacement in the direction perpendicular to the stacking direction, that is, the direction parallel to the surfaces of the metal support frame 50 and the metal separators 60a and 60b. The distance between the outer wall of the portion 61 and the inner wall of the dent 51 may be shorter than the distance between the tip of the protrusion 61 and the bottom of the dent 51.

  In addition, in order to change the direction of the flow of the slip flow, it is desirable that the shape of the protruding portion 61 and the indented portion 51 is a rectangle or a shape having a sharp edge. good. For example, the protrusion 61 may have a hemispherical tip, and the dent 51 may have a hemispherical dent.

  As described above, according to the fuel cell FC according to the present embodiment, the tips of the protruding portions 61 formed on the metal separators 60a and 60b as the rectifying portions are formed on the metal support frame 50. Arranged in each recess 51. Therefore, the distance between the tip of the protrusion 61 and the bottom of the dent 51 can be made relatively large to achieve insulation between the metal support frame 50 and the metal separators 60a and 60b. The rectifying effect can be improved by suppressing or preventing the slip flow across the portion 61.

  The present embodiment may be modified as shown in FIG. FIG. 9 is an explanatory view showing a modification of this embodiment. In the above embodiment, the protrusions 61 are formed on the metal separators 60 a and 60 b, and the dent 51 is formed on the metal support frame 50. On the other hand, in this modification, the protrusion 52 is formed on the metal support frame 50, and the recess 63 is formed on the metal separator 60a (60b). Also in this modification, the insertion allowance of the projecting portion 52 with respect to the recessed portion 63 is adjusted by the height (thickness) of the seal member 10.

  Also in this modification, since the same relationship as described in the above embodiment exists between the protruding portion 52 and the indented portion 63, the same advantages as in the above embodiment can be obtained.

Other examples:
(1) Although the hydrogen permeable membrane type membrane electrode assembly has been described as an example in each of the above embodiments, it can be applied to a non-self-supporting solid oxide type membrane electrode assembly that needs to be supported by a support frame. Needless to say you get. Even in a non-self-supporting solid oxide membrane electrode assembly, a metal material must be used as a frame for supporting the membrane electrode assembly from the viewpoint of fastening weight and high operating temperature. This is because it is necessary to ensure insulation between the separator and the separator.

(2) In the above embodiment, the example in which the protruding portion 61 is included in the recessed portion 51 has been described. However, the distal end surface of the protruding portion 61 and the opening surface of the recessed portion 51 are the same. It may be arranged in the plane. Also in this case, the slip flow cannot directly straddle (pass) the protruding portion 61, and the slip flow can be suppressed or prevented.

(3) In the above embodiment, the example in which the outer periphery of the protrusion 61 (52) and the inner wall of the recess 51 (63) are close to each other has been described. The pressure loss of the flow path 511 is made higher than the pressure loss of the reaction gas internal flow paths 37a and 37c by providing an annular protrusion or a dot-like protrusion on the protruding portion 61 or the recessed portion 51 with a certain distance from the inner wall of 51. You may do it.

(4) In each of the above embodiments, the space between the dent 51 and the dent 51 is wide, and each dent is formed in a groove shape. However, a portion where the corresponding protrusion 61 is not disposed is also cut. Alternatively, the protrusion 61 may be surrounded by a thin wall portion by etching. In this case, the cross-sectional area of the reaction gas internal channels 37a and 37c can be enlarged, and the change in flow rate can be flexibly handled. On the other hand, the pressure loss of the flow path 511 can be maintained higher than the pressure loss of the reaction gas internal flow paths 37a and 37c.

(5) In each of the embodiments described above, the metal material is used as the support frame 50 and the separators 60a and 60b. However, the conductive material is another conductive material, and has the same pair-fastening performance as that of the metal material. Any material can be used in the same manner. This is because the good insulation provided by the rectifying member 51 used in each of the above embodiments is required.

(6) In the embodiment of the fuel cell system described above, the metal support frame 50 including the lattice-like portion 56 has been described. However, the metal frame provided with the opening without using the lattice-like portion 56 is used. Also good.

(7) In the above embodiment, the fuel cell constituent member that supports the membrane electrode assembly 30 is called the metal support frame 50, but it may be called a battery plate. The metal separators 60a and 60b may be called flow path plates.

  As mentioned above, although this invention was demonstrated based on the Example, embodiment mentioned above is for making an understanding of this invention easy, and does not limit this invention. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

It is explanatory drawing which shows schematic structure of the fuel cell system used for a present Example. It is explanatory drawing which shows a part of cut surface which cut | disconnected the fuel cell in FIG. 1 by the cutting line XX. It is explanatory drawing which shows the anode side of the metal support frame used for a present Example. It is explanatory drawing which shows the cathode side of the metal support frame used for a present Example. It is explanatory drawing which shows the opposing surface with the metal support frame of the anode side metal separator used for a present Example. It is the top view which looked at the cell from the anode side which shows the structure currently formed in the metal support frame, and the structural member arrange | positioned between the metal support frame and the metal separator with a dotted line. It is sectional drawing which shows the cross section which cut | disconnected the cell by the YY cutting | disconnection line in FIG. It is explanatory drawing which expands and shows the protruding part and dent part in FIG. It is explanatory drawing which shows the modification of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell sealing member 25a ... Fuel gas supply manifold 25b ... Fuel gas discharge manifold 26a ... Oxidation gas supply manifold 26b ... Oxidation gas discharge manifold 27a ... Refrigerant supply manifold 27b ... Refrigerant discharge manifold 30 ... Membrane electrode assembly 31 ... Electrolyte Layer 32 ... Hydrogen permeable membrane layer 33 ... Cathode 37a ... Fuel gas internal flow path 37c ... Oxidation gas internal flow path 38a ... Anode side gas diffusion layer 38c ... Cathode side gas diffusion layer 50 ... Metal support frame 51 ... Recessed portion 52 ... Protruding part (rectifying part)
56 ... Grid-shaped portion 561 ... Hole 520a ... Fuel gas supply manifold forming portion 520b Fuel gas discharge manifold forming portion 521a ... Oxidizing gas supply manifold forming portion 521b ... Oxidizing gas discharge manifold forming portion 522a ... Refrigerant supply manifold forming portion 522b ... Refrigerant discharge Manifold forming part 60a ... Cathode separator 60b ... Anode separator 61 ... Protruding part (rectifying part)
62a, 62b ... Refrigerant flow path 63 ... Recessed portion 620a ... Fuel gas supply manifold forming portion 620b Fuel gas discharge manifold forming portion 621a ... Oxidizing gas supply manifold forming portion 621b ... Oxidizing gas discharge manifold forming portion 622a ... Refrigerant supply manifold forming portion 622b ... Refrigerant discharge manifold forming part 100 ... Single cell 200 ... Fuel gas supply pipe 201 ... Fuel gas discharge pipe 201a ... Discharge branch pipe 201b ... Circulation branch pipe FCS ... Fuel cell system

Claims (8)

A fuel cell,
A membrane electrode assembly;
A plate-like metal support frame that supports the outer edge of the membrane electrode assembly, and a metal support frame having one or more indentations,
A pair of metal separators disposed on both surfaces of the metal support frame, the metal separator having one or a plurality of protrusions corresponding to each of the dents;
A reaction gas internal flow path formed by the metal support frame and the pair of metal separators;
An insulating seal member disposed between the metal support frame and the pair of metal separators, wherein a distance between each metal separator and the metal support frame is set to each protrusion. The pressure loss of the flow path formed by each of the recesses is higher than the pressure loss of the reaction gas internal flow path, and the distance between the tip of each protrusion and the bottom of each recess is defined. A fuel cell comprising an insulating sealing member. A fuel cell,
A pair of metal separators having one or more indentations;
A membrane electrode assembly;
A plate-shaped metal support frame that supports an outer edge of the membrane electrode assembly, wherein the pair of metal separators are disposed on both surfaces thereof, and one or a plurality of protrusions corresponding to the indentations are provided. A metal support frame having,
A reaction gas internal flow path formed by the metal support frame and the pair of metal separators;
An insulating seal member disposed between the metal support frame and the pair of metal separators, wherein a distance between each metal separator and the metal support frame is set to each protrusion. The pressure loss of the flow path formed by each of the recesses is higher than the pressure loss of the reaction gas internal flow path, and the distance between the tip of each protrusion and the bottom of each recess is defined. A fuel cell comprising an insulating sealing member. The fuel cell according to claim 1 or 2,
The sealing member is
The protrusions and the dents are defined by defining the separation distance so that the front ends of the protrusions are included in the same plane as the opening surface of the dents or included in the dents. A fuel cell in which the pressure loss of the flow path formed by the above is made higher than the pressure loss of the reaction gas internal flow path. The fuel cell according to any one of claims 1 to 3,
The pair of metal separators further includes a reaction gas supply unit for supplying a reaction gas to the membrane electrode assembly,
Each of the protrusions is a rectification unit that is formed between the reaction gas supply unit and the membrane electrode assembly and rectifies the reaction gas supplied from the reaction gas supply unit to the membrane electrode assembly. battery. The fuel cell according to any one of claims 1 to 4, wherein
The pair of metal separators further includes a reaction gas discharge part for discharging reaction gas from the membrane electrode assembly,
Each of the protrusions is a rectification unit that is formed between the membrane electrode assembly and the reaction gas discharge unit and rectifies the reaction gas discharged from the membrane electrode assembly to the reaction gas discharge unit. battery. The fuel cell according to any one of claims 1 to 5,
The fuel cell is a hydrogen separation membrane type membrane electrode assembly. The fuel cell according to any one of claims 1 to 6,
The protrusions and the recesses each have a rectangular cross section. The fuel cell according to any one of claims 1 to 7,
A fuel cell in which a diffusion layer is disposed between the membrane electrode assembly and each metal separator.

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