JP2008004300A - Press separator for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the partial decrease in conductivity between the surface of a press separator in a power generation region and other members and equalize the conductivity. <P>SOLUTION: When a plurality of fluid channels 35 containing parts having different curvatures from each other are arranged in parallel, in at least one surface of the press separator 20, the width in at least any one fluid channel 35 is made wider in a part having a larger curvature out of the parts having different curvatures. The parts where the curvatures of the fluid channel 35 are different include a straight channel 35s in a straight part S and a curved channel 35t in a turn part T of the fluid channel 35, for example. Preferably, the one surface is the surface on a membrane-electrode assembly side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell press separator. More specifically, the present invention relates to an improvement in the structure or shape of the press separator, and further relates to a molding die for the press separator, a manufacturing method, and the like.

  In general, a fuel cell (for example, a polymer electrolyte fuel cell) has a structure in which a cell is formed by sandwiching a membrane-electrode assembly (MEA) with, for example, a pair of separators, and a plurality of such cells are stacked. It has become.

  As a separator capable of reducing the size of such a fuel cell, a separator (metal separator) made of a metal (for example, stainless steel) that is stronger and thinner than a carbon-based material is often used. According to the metal separator, the number of parts can be reduced by utilizing the spring property (flexibility) of the separator itself. In this case, the groove-like fluid flow paths on the front and back surfaces of the metal separator are generally formed by press molding, and according to this, an integral fluid flow path is formed on the front and back surfaces of the separator. can do.

Conventionally, as a press separator for such a fuel cell, a so-called serpentine-type press separator having a so-called serpentine flow path bent so as to meander in the middle (so-called serpentine-type press separator) is also used (for example, Patent Document 1). reference).
JP 2003-242994 A

  However, in the press separator, the curvature of the bent part (turn part) of the serpentine flow path is larger than that of the other part (for example, the straight part). -The contact area with the electrode assembly (MEA) may be reduced. In such a case, there is a problem in that the conductivity in the power generation region may be inferior.

  Accordingly, the present invention provides a fuel cell press separator capable of suppressing the partial inferior conductivity between the surface of the press separator in the power generation region and other members and homogenizing the conductivity. For the purpose.

  In order to solve this problem, the present inventor has made various studies. From the viewpoint of ensuring conductivity in the power generation region, it is preferable that the contact area between the separator and the MEA is sufficiently ensured. However, in actuality, the contact area is reduced at the turn portion of the fluid flow path, which may result in poor conductivity. The inventor who examined this point does not have the same contact area between the MEA and the separator even if the straight part and the turn part described above are press-molded so as to have the same flow path pitch (same repetition width). Focused on that. This is because the shoulder portion (both corners) of the convex portion of the cross section of the flow path is bent at the time of press molding, particularly at the turn portion (at the time of molding, the corner R is increased so that the shoulder portion is pulled, For example, even if the cross-sectional shape shown by the imaginary line in FIG. 6 is intended, the separator is actually shown by the solid line. (See FIG. 6). In this case, since the width of the flat portion formed between the shoulder portions (both corners) is narrowed, the contact area between the MEA and the separator is reduced by that much, particularly in the turn portion. The present inventor, who has further studied the above points, has obtained knowledge that leads to the solution of such problems.

  The present invention is based on such findings, and is a press separator in which a plurality of fluid flow paths including portions having different curvatures are arranged in parallel, and at least one of the surfaces of the press separator is at least one of the press separators. The width of the fluid channel is wider in the portion with the larger curvature among the portions with different curvatures.

  The fluid flow path, which is wider at the part with the larger curvature, was formed at the part with the smaller curvature even if the shoulder part (both corners) of the convex part slipped and the flat part became narrower during press molding. It is possible to ensure a flat portion having a width equal to or greater than that of the fluid flow path. According to this, even in a turn part that is prone to deform in cross-section during press molding, a contact area equivalent to or larger than that of the straight part is realized, and the conductivity between the MEA and the separator is prevented from being partially inferior. Can be homogenized.

  In such a fuel cell press separator, the one surface is preferably a surface on the membrane-electrode assembly side. If the fluid flow path of the turn part is widened at least on the surface on the membrane-electrode assembly side, the contact area between the MEA and the separator can be suppressed from decreasing in the turn part.

  The fluid flow path of the fuel cell press separator is a serpentine-type flow path formed so as to meander in the plane of the separator. According to the present invention, in a fuel cell press separator having such a serpentine-type flow path, it is possible to suppress partial inferior conductivity between the MEA and the separator.

  Furthermore, in the fuel cell press separator of the present invention, the portions where the curvatures of the fluid flow paths are different from each other are a straight path in the straight portion and a curved path in the turn portion of the fluid flow path.

  Moreover, it is preferable that the said fluid flow path is a thing with the arrangement | positioning space | interval in the said curved path wider than the arrangement | positioning space | interval in the said linear path. It is possible to suppress a decrease in the contact area between the MEA and the separator in the turn portion by setting a wide arrangement interval (a pitch of arrangement of adjacent flow paths) in the curved path.

  In the fuel cell press separator according to the present invention, in each of the fluid flow paths, the straight path and the curved path communicate with each other at the turn portion. In this case, the grooves constituting the fluid flow path are connected so as to continue from the straight portion to the turn portion.

  In addition, it is preferable that the plurality of fluid flow paths in the fuel cell press separator have a total flow path width in the turn portion wider than a total flow path width in the straight portion. If the total flow path width in the turn part is widened, the width of each fluid flow path in the turn part can be increased accordingly, so that the contact area between the MEA and the separator is reduced in the turn part. Easy to suppress.

  Furthermore, in the fluid flow channel, it is preferable that an arrangement interval between adjacent flow channels is wider in the turn portion than in the straight portion. If the flow path arrangement interval in the turn part is wide, the width of each fluid flow path in the turn part can be increased by that much, so the contact area between the MEA and the separator is reduced in the turn part. It becomes easy to suppress.

  The molding die according to the present invention has a mold for press-molding the above-described fuel cell press separator.

  Furthermore, a method for producing a fuel cell press separator using this molding die is also preferred.

  The fuel cell according to the present invention includes any of the fuel cell press separators described above.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to suppress that the electrical conductivity between the press separator surface and other members in a power generation area | region is partially inferior, and to make the electrical conductivity between these uniform.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  1 to 5 show an embodiment of a press separator for a fuel cell according to the present invention. This press separator 20 is a separator having a structure in which a plurality of fluid passages (for example, an oxidizing gas passage 34 or a hydrogen gas passage 35) including portions having different curvatures are arranged in parallel. . Further, in the press separator 20 of the present embodiment, on at least one surface, the flow path width in at least one of the fluid flow paths is wider in a portion having a larger curvature among portions having different curvatures. Is.

  In the embodiment described below, first, a schematic configuration of a fuel cell stack in which a cell (power generation cell) 2 and a plurality of cells 2 constituting the fuel cell 1 are stacked will be described, and then the cell 2 is configured. The structure of the press separator (hereinafter also simply referred to as a separator) 20 will be described in detail. 1, detailed illustrations of the gas flow path 35 and the cooling water flow path 36 formed in the press separator 20 are omitted, and an example of the gas flow path 34 (35) is illustrated in FIG. .

  FIG. 1 shows a schematic configuration of a cell 2 of a fuel cell 1 in the present embodiment. The cells 2 configured as shown in the figure are sequentially stacked to form a cell stack 3 (see FIG. 2). Further, in the fuel cell stack composed of the cell stack 3 or the like, for example, both ends of the stack are sandwiched between a pair of end plates 8, and a restraining member including a tension plate 9 is arranged so as to connect the end plates 8 to each other. In this state, a load in the stacking direction is applied and fastened (see FIG. 2).

  The fuel cell 1 including such a fuel cell stack can be used as, for example, an in-vehicle power generation system of a fuel cell vehicle (FCHV; Fuel Cell Hybrid Vehicle), but is not limited thereto. It can be used as a power generation system mounted on various mobile bodies (for example, ships, airplanes, etc.), self-propelled devices such as robots, and also as a stationary power generation system.

  The cell 2 includes an electrolyte, specifically, a membrane-electrode assembly (hereinafter referred to as MEA) 30 and a pair of separators 20 sandwiching the MEA 30 (in FIG. 1, reference numerals 20a and 20b are attached respectively). Etc.) (see FIG. 1). The MEA 30 and the separators 20a and 20b are formed in a substantially rectangular plate shape. Further, the MEA 30 is formed so that its outer shape is smaller than the outer shape of each separator 20a, 20b.

  The MEA 30 includes a polymer electrolyte membrane (hereinafter also simply referred to as an electrolyte membrane) 31 made of a polymer material ion exchange membrane, and a pair of electrodes (an anode side diffusion electrode and a cathode side diffusion electrode) sandwiching the electrolyte membrane 31 from both sides. 32a and 32b (see FIG. 1). The electrolyte membrane 31 is formed larger than the electrodes 32a and 32b. The electrodes 32a and 32b are joined to the electrolyte membrane 31 by, for example, a hot press method while leaving the peripheral edge portion 33.

  The electrodes 32a and 32b constituting the MEA 30 are made of, for example, a porous carbon material (diffusion layer) carrying a catalyst such as platinum attached to the surface thereof. One electrode (anode) 32a is supplied with hydrogen gas as a fuel gas (reactive gas), and the other electrode (cathode) 32b is supplied with an oxidizing gas (reactive gas) such as air or an oxidant. An electrochemical reaction is generated in the MEA 30 by the gas, and the electromotive force of the cell 2 is obtained.

  The separator 20 (20a, 20b) is made of a gas impermeable conductive material. Examples of the conductive material include carbon and a hard resin having conductivity, and metals such as aluminum and stainless steel. The base material of the separator 20 (20a, 20b) of the present embodiment is formed of a plate-like metal (metal separator), and a film with excellent corrosion resistance is provided on the surface of the base material on the electrodes 32a, 32b side. (For example, a film formed by gold plating) is formed.

  Further, a groove-like flow path constituted by a plurality of concave portions is formed on both surfaces of the separators 20a and 20b. These flow paths can be formed by press molding in the case of the separators 20a and 20b of the present embodiment in which the base material is formed of, for example, a plate-like metal. The groove-shaped flow path formed in this way constitutes an oxidizing gas flow path 34, a hydrogen gas flow path 35, or a cooling water flow path 36. More specifically, a plurality of gas passages 35 for hydrogen gas are formed on the inner surface on the electrode 32a side of the separator 20a, and a plurality of cooling water passages 36 are formed on the back surface (outer surface). (See FIG. 1). Similarly, a plurality of gas channels 34 for oxidizing gas are formed on the inner surface of the separator 20b on the electrode 32b side, and a plurality of cooling water channels 36 are formed on the back surface (outer surface) (FIG. 1). reference). For example, in the case of the present embodiment, regarding the two adjacent cells 2, 2, when the outer surface of the separator 20 a of one cell 2 and the outer surface of the separator 20 b of the cell 2 adjacent to this are combined, The channel 36 is integrated so that a channel having a rectangular or honeycomb cross section is formed.

  Furthermore, as described above, the separators 20a and 20b have a relationship in which at least the uneven shape for forming a fluid flow path is reversed between the front surface and the back surface. More specifically, in the separator 20a, the back surface of the convex shape (convex rib) forming the hydrogen gas gas flow path 35 is a concave shape (concave groove) forming the cooling water flow path 36, and the gas flow path The back surface of the concave shape (concave groove) forming 35 is a convex shape (convex rib) forming the cooling water channel 36. Furthermore, in the separator 20b, the back surface of the convex shape (convex rib) that forms the gas flow path 34 of the oxidizing gas has a concave shape (concave groove) that forms the cooling water flow path 36, and the concave that forms the gas flow path 34. The back surface of the shape (concave groove) is a convex shape (convex rib) forming the cooling water flow path 36.

  Further, in the vicinity of the longitudinal ends of the separators 20a and 20b (in the case of this embodiment, in the vicinity of one end shown on the left side in FIG. 1), the manifold 15a on the inlet side of the oxidizing gas, hydrogen gas An outlet side manifold 16b and a cooling water outlet side manifold 17b are formed. For example, in the case of this embodiment, these manifolds 15a, 16b, and 17b are formed by substantially rectangular or trapezoidal through holes provided in the separators 20a and 20b (see FIG. 1). Further, an oxidant gas outlet side manifold 15b, a hydrogen gas inlet side manifold 16a, and a cooling water inlet side manifold 17a are formed at opposite ends of the separators 20a and 20b. In the case of this embodiment, these manifolds 15b, 16a, and 17a are also formed by substantially rectangular or trapezoidal through holes (see FIG. 1). In FIG. 3, the reference numerals of the manifolds are shown in a form in which the suffixes a and b are omitted.

  Among the manifolds as described above, the inlet side manifold 16a and the outlet side manifold 16b for the hydrogen gas in the separator 20a are connected to the inlet side communication passage 61 and the outlet side communication passage 62 formed in the separator 20a in a groove shape. Each communicates with a gas flow path 35 of hydrogen gas. Similarly, the inlet side manifold 15a and the outlet side manifold 15b for the oxidizing gas in the separator 20b are oxidized via the inlet side communication passage 63 and the outlet side communication passage 64 formed in the separator 20b in a groove shape. The gas communicates with the gas flow path 34 (see FIG. 1). Further, the inlet side manifold 17a and the outlet side manifold 17b of the cooling water in each separator 20a, 20b are connected to each separator 20a, 20b through an inlet side communication passage 65 and an outlet side communication passage 66 formed in a groove shape. Each communicates with the cooling water passage 36. With the configuration of the separators 20a and 20b as described above, the cell 2 is supplied with oxidizing gas, hydrogen gas, and cooling water. As a specific example, when the cells 2 are stacked, for example, hydrogen gas passes from the inlet side manifold 16a of the separator 20a through the communication passage 61 and flows into the gas flow path 35, and is supplied to the power generation of the MEA 30. After that, the fluid passes through the communication passage 62 and flows out to the outlet side manifold 16b.

  The first seal member 13a and the second seal member 13b are both formed of a plurality of members (for example, four small rectangular frames and a large frame for forming a fluid flow path) (FIG. 1). Among these, the first seal member 13a is provided between the MEA 30 and the separator 20a. More specifically, a part of the first seal member 13a is a peripheral portion 33 of the electrolyte membrane 31 and a gas flow path 35 of the separator 20a. It is provided so that it may interpose between the surrounding parts. The second seal member 13b is provided between the MEA 30 and the separator 20b. More specifically, a part of the second seal member 13b is a peripheral portion 33 of the electrolyte membrane 31 and the gas channel 34 of the separator 20b. It is provided so as to be interposed between the surrounding portions.

  Furthermore, a plurality of members (for example, four small rectangular frames and a large frame for forming a fluid flow path) are formed between the separators 20b and 20a of the adjacent cells 2 and 2. A third seal member 13c is provided (see FIG. 1). The third seal member 13c is provided so as to be interposed between a portion around the cooling water passage 36 in the separator 20b and a portion around the cooling water passage 36 in the separator 20a, and seals between them. It is.

  In addition, as the first to third seal members 13a to 13c, an elastic body (gasket) that seals a fluid by physical contact with an adjacent member, or an adhesive that is bonded by chemical bonding with an adjacent member. An agent or the like can be used. For example, in this embodiment, a member that is physically sealed by elasticity is employed as each of the seal members 13a to 13c, but instead, a member that is sealed by a chemical bond such as the adhesive described above may be employed.

  The frame-shaped member 40 is a member made of, for example, resin (hereinafter also referred to as a resin frame) that is sandwiched between the separators 20a and 20b together with the MEA 30. For example, in this embodiment, a thin frame-shaped resin frame 40 is interposed between the separators 20a and 20b, and the resin frame 40 sandwiches at least a part of the MEA 30, for example, a portion along the peripheral edge 33 from the front side and the back side. I have to. The resin frame 40 provided in this way functions as a spacer between the separators 20 (20a, 20b) that supports the fastening force, functions as an insulating member, and as a reinforcing member that reinforces the rigidity of the separator 20 (20a, 20b). Demonstrate the function.

  Next, the configuration of the fuel cell 1 will be briefly described (see FIG. 2). The fuel cell 1 in the present embodiment has a cell stack 3 formed by stacking a plurality of cells 2, and is sequentially arranged outside the cells 2 and 2 located at both ends of the cell stack 3 with output terminals. An electric plate, an insulating plate, and an end plate 8 are arranged (see FIG. 2). Further, the tension plate 9 that restrains the cell stack 3 and the like in a stacked state is provided so as to bridge between both end plates 8 and 8, and for example, a pair is opposed to both sides of the stack. Is arranged (see FIG. 2). The tension plate 9 is connected to the end plates 8 and 8 and maintains a state in which a predetermined fastening force (compression load) is applied in the stacking direction of the cell stack 3. In addition, an insulating film (not shown) is formed on the inner surface of the tension plate 9 (the surface facing the cell stack 3) in order to prevent leakage and sparks. The insulating film is formed by, for example, an insulating tape attached to the inner surface of the tension plate 9, or a resin coating applied so as to cover the surface. Reference numeral 12 denotes a pair of plate-like members for sandwiching an elastic module made of, for example, a coil spring that applies a fastening force (compression load) to the fuel cell stack (see FIG. 2).

  Next, the structure of the separator (press separator) 20 for the fuel cell 1 according to the present invention will be described (see FIG. 3 and the like).

  The separator 20 in the present embodiment is a so-called serpentine type formed so that the fluid flow path is folded halfway. The fluid channel formed in such a meandering shape has a shape in which a plurality of channels including portions having different curvatures are arranged in parallel to each other (see FIG. 3). Here, the fluid flow path includes both the oxidizing gas flow path 34 and the hydrogen gas flow path 35 described above, but in this embodiment, the hydrogen gas flow path 35 is exemplified. (See FIG. 3).

  Here, portions having different curvatures in the gas flow path (fluid flow path) 35 are, for example, a straight path 35 s mainly constituting the straight portion S and a curved path 35 t mainly constituting the turn portion T, for example. It is each part combined in order to form a serpentine type flow path. The turn part T is a part mainly constituted by a curved path 35t in order to form a folded part of the serpentine type flow path, and is combined with the straight part S mainly constituted by a straight path 35s to form the serpentine type flow path. (See FIG. 3). 3 illustrates a serpentine type flow path having a relatively simple shape, but this is only an example. For example, the turn portion T may include a straight path 35s, or the straight portion S may be curved. A path 35t may be included.

  In the separator 20 having such a structure, the curved path 35t described above is provided so that the flow path width is at least as wide as the flow path width in the straight path 35s (see FIG. 3). This will be described in more detail with reference to the cross-sectional shape of the separator 20 (see FIGS. 4 and 5). The flow path pitch (arrangement interval of adjacent flow paths) Pb of the curved path 35t shown in FIG. It is set to be larger than the flow path pitch Pa of the straight path 35s shown (Pb> Pa). In such a case, even if deformation occurs during press molding, the width Fb of the flat portion of the separator 20 in the curved path 35t is at least as wide as the width Fa of the flat portion of the separator 20 in the straight path 35s. (See FIGS. 4 and 5).

  That is, at the time of press molding, deformation is more likely to occur in the curved path 35t than in the straight path 35s. For example, even if a cross-sectional shape as indicated by an imaginary line in FIG. End up. In this case, as shown in the figure, the shoulder portions (both corners) of the convex portion of the flow path cross section become slack and become gentle, and the width Fb of the flat portion formed between the shoulder portions (both corners) becomes smaller. As a result, it becomes narrower (Fb → Fb ′), and as a result, the contact area between the MEA 30 and the separator 20 in the turn part T may decrease. In this regard, in the present embodiment, the flow path width of the curved path 35t is formed wide in advance (the flow path pitch Pb is made larger than Pa), so that the cross-sectional shape is deformed as described above, and the width Fb of the flat portion. Even if it becomes narrow, it is possible to secure at least a width equal to the flat portion width Fa in the straight path 35s. In other words, since the curved path 35t is widened in advance by taking into account the deformation (a decrease in the width of the flat portion) associated with press forming, the influence of the difference between the intended shape and the actual shape is avoided. It is possible. According to the above, it is possible to suppress the occurrence of bias in the contact area between the surface of the separator 20 and the MEA 30 in the power generation area of the fuel cell 1. Therefore, it is possible to suppress that the conductivity between both members is partially inferior, thereby making the conductivity uniform.

  In the present embodiment, the flow path width of the curved path 35t is widened for the gas flow path 35 of hydrogen gas, and the curved path (34t) of the gas flow path 34 for the oxidizing gas is also not shown in FIG. Is wider than the straight path (34s). In such a case, it is possible to suppress the occurrence of bias in the contact area between the separator 20 and the MEA 30 on either the anode side or the cathode side of the MEA 30 and to homogenize the conductivity between the two members.

  As shown in FIG. 3, in the present embodiment, a straight path 35 s and a curved path 35 t communicate with each other in a plurality of gas flow paths (fluid flow paths) 35. That is, one gas flow path 35 has a structure in which not only the straight portion S but also the turn portion T communicates from the hydrogen gas inlet side manifold 16a to the outlet side manifold 16b (see FIG. 3). The separator 20 of this embodiment having such a structure is characteristic in the following points.

  That is, in the case of the metal separator 20 in which integral fluid passages are formed on the front and back by press molding, the gas passage 35 for hydrogen gas (or the gas passage 34 for oxidizing gas) and the cooling water passage 36 are on the front and back sides. Will be formed simultaneously. In this case, as a structure for establishing the flow between the manifold and the fluid flow path for both hydrogen gas (or oxidizing gas) and cooling water, a plurality of protrusions protruding on the front side and another plurality of protrusions protruding on the back side are provided. Conventionally, an embossed portion made of a material and a space between these protrusions are circulated. In the case of the serpentine-type separator 20, such an embossed part may be arranged at the folded part (turn part) of the fluid flow path. However, in the embossed portion, it is necessary to secure the respective flow paths of hydrogen gas (or oxidizing gas) and cooling water on both the front and back surfaces of the separator 20, so that the total thickness (total height) of the separator 20 is determined for each flow. As a result of apportioning by the road, the height of each flow passage is limited. From such a technical background, when the embossed portion is arranged in the folded portion, the generated water accompanying power generation may stay in the embossed portion. In this case, there is a possibility that the power generation region decreases as the number of flow paths through which the gas can flow decreases, or that the accumulated generated water freezes due to a temperature drop and affects the electrode. Furthermore, the pressure loss (differential pressure) of the flow path increases at the embossed portion, and the embossed portion has a small contact area between the separator 20 and the MEA 30, which may be disadvantageous in that the power generation efficiency is inferior. is there.

  On the other hand, in the case of the separator 20 of the present embodiment in which the gas flow paths 35 (34) communicate with each other as described above, there is no such embossed portion, and one groove is formed from the inlet to the outlet. Since the structure continues, pressure loss (differential pressure) is unlikely to increase and it is easy to suppress the retention of generated water. For this reason, it is easy to suppress reduction of the power generation area due to the staying water, and it is possible to avoid the influence of the electrodes due to the influence of freezing. Furthermore, since the gas flow path 35 (34) continues and the contact portion with the MEA 30 also continues, a similar contact area can be secured between the straight portion S and the turn portion T, thereby increasing the power generation output. Can also be achieved. In particular, the fact that the embossed portion is eliminated so that the reduction of the power generation region can be suppressed is coupled with the fact that the flat portion width Fb in the turn portion T is secured as described above to suppress the bias of the contact region. This is preferable in that the electrical conductivity between 20 and MEA 30 can be further homogenized. As described above, in the separator 20 of this embodiment in which characteristic structures are combined, it is also possible to obtain a synergistic effect due to these.

  According to the separator 20 having the structure as described above, in the power generation region, that is, in the region where a reaction gas (hydrogen gas and oxidizing gas) flows between the MEA 30 of the separator 20 and a chemical reaction occurs, It is possible to suppress partial inferior conductivity between the MEA 30 and homogenize the conductivity between them.

  Moreover, according to the separator 20 of the present embodiment, it is also characteristic that a fundamentally different effect can be obtained from the carbon separator. In other words, as the characteristics of the metal separator, it is difficult to achieve both the gas flow (reactive gas flow) and the refrigerant flow (cooling water flow) because of the structure in which the unevenness is reversed on both sides. It can be mentioned that it contains structural constraints, which are very different from carbon separators. However, as explained so far, according to the separator 20 of the present embodiment, the conductivity with the MEA 30 that directly affects power generation can be homogenized in the cell plane, and the restrictions peculiar to the metal separator different from the carbon separator are eliminated. It is characteristic in that it can.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the present embodiment, the case where the present invention is applied to the gas flow path of the reactive gas (hydrogen gas and oxidizing gas) (particularly, the hydrogen gas flow path 35) has been described, but the technology is applied to the cooling water flow path 36. Of course it is also possible. In such a case, the conductivity (conductivity) between the adjacent cells 2 can be homogenized in the cell plane, so that the conductivity in the cell stack 3 can be further improved as a whole. become able to. In this case, it is possible to make the conductivity uniform not only on the MEA 30 side surface of the separator 20 but also on both surfaces including the refrigerant side surface.

  In addition, paying attention to the total flow path width of the gas flow paths 35 (34) in the separator 20, it is also preferable to set the total flow path width in the turn part T wider than the total flow path width in the straight part S. If the total flow path width in the turn part T is widened, the width of each gas flow path 35 (34) in the turn part T can be uniformly widened accordingly. The conductivity can be homogenized throughout the turn part T. For example, the technology according to the present invention can be applied to only a few (for example, one) of the gas flow paths 35 (34) arranged in parallel, but the conductivity between the MEA 30 and the separator 20 is not limited. From the viewpoint of homogenizing the whole in the power generation region, it is desirable to apply to all the gas flow paths 35 (34).

  Although not shown in particular, a mold for press-molding the separator 20 described above (for example, a mold designed so that the fluid flow path width in the turn portion is wider than that in the straight portion S). According to the mold, the separator 20 according to the present embodiment can be easily press-molded (including a roll press). Therefore, if the molding using such a mold is performed, a characteristic separator 20 different from the conventional structure can be manufactured.

It is a disassembled perspective view which shows the structural example of the cell in this embodiment. It is a perspective view which shows roughly the structural example of a fuel cell stack. 1 is a diagram illustrating an embodiment of the present invention, and schematically illustrates a structure of a metal separator on a fluid flow path (hydrogen gas flow path) side. It is sectional drawing in the IV line part of FIG. 3 which shows the structural example of a straight path. It is sectional drawing in the V-line part of FIG. 3 which shows the structural example of a curved path. It is sectional drawing which shows schematically a mode that a fluid flow path deform | transforms especially in a turn part at the time of press molding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell, 2 ... Cell, 20 (20a, 20b) ... Separator (press separator), 30 ... MEA (membrane-electrode assembly), 34 ... Gas flow path (fluid flow path) of oxidizing gas, 34s ... Oxidizing gas 35t ... Hydrogen gas gas channel (fluid channel), 35s ... Hydrogen gas gas channel, 35t ... Hydrogen gas Curve path of gas flow path, S ... Straight part of fluid flow path, T ... Turn part of fluid flow path

Claims (11)

A press separator in which a plurality of fluid flow paths including portions having different curvatures are arranged in parallel,
A fuel cell characterized in that, on at least one surface of the press separator, at least one of the fluid channels has a wider channel width in a portion having a larger curvature among the portions having different curvatures. Press separator.   2. The fuel cell press separator according to claim 1, wherein the one surface is a surface on the membrane-electrode assembly side.   3. The fuel cell press separator according to claim 1, wherein the fluid channel is a serpentine-type channel formed to meander in the plane of the separator. 4.   4. The fuel cell press according to claim 1, wherein the portions having different curvatures of the fluid flow path are a straight path in a straight portion and a curved path in a turn portion of the fluid flow path. 5. Separator.   5. The fuel cell press separator according to claim 4, wherein the fluid flow path has a wider arrangement interval in the curved path than an arrangement interval in the straight path.   6. The fuel cell press separator according to claim 4, wherein in each of the fluid flow paths, the straight path and the curved path communicate with each other at the turn portion.   The fuel cell according to any one of claims 4 to 6, wherein the plurality of fluid flow paths have a total flow path width in the turn portion that is greater than a total flow path width in the straight portion. Press separator.   8. The fuel cell press separator according to claim 4, wherein in the fluid flow path, an interval between adjacent flow paths is wider in the turn part than in the straight part. 9. .   A molding die having a mold for press-molding the fuel cell press separator according to claim 1.   A method for producing a press separator for a fuel cell, wherein the molding die according to claim 9 is used.   A fuel cell comprising the fuel cell press separator according to claim 1.

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