Fuel cell separator and fuel cell stack

Abstract

To easily position laminated units, and suppress the deformation of a separator.SOLUTION: A fuel cell stack 16 includes a power generation cell laminate 12 in which a plurality of laminate units E each having an electrolyte membrane / electrode structure 30 and a separator 28 are laminated in the lamination direction. The separator 28 is provided with a positioning portion 58 for positioning the laminate units E by laminating the laminate units in the stacking direction. Ribs 118 projecting in the thickness direction of the separator and extending in the plane direction of the separator are provided on the peripheral edge portion 114 of the positioning portion 58 of the separator 28.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a separator for a fuel cell that forms a stacking unit of a power-generating cell stack, and to a fuel cell stack including the separator. [Background technology]

[0002] Generally, fuel cells are used in the form of a fuel cell stack including a power generation cell laminate in which a plurality of power generation cells (unit fuel cells) are stacked, and end plates and the like disposed on both ends of the power generation cell laminate in the stacking direction. A power generation cell is configured by sandwiching a membrane electrode assembly between a pair of separators. In this type of fuel cell stack, a so-called internal manifold may be configured to supply fluids such as reactant gases to each membrane electrode assembly of the power generation cell stack. In this case, in order to ensure good fluid sealing, it is necessary that the stack units of the power generation cell stack are stacked in a state where they are positioned with high precision.

[0003] Therefore, for example, as disclosed in Patent Document 1, it is conceivable to provide a positioning hole in the stacking unit. The positioning holes of each stacking unit are arranged so that the stacking units are positioned at a predetermined stacking position by overlapping each other in the stacking direction. By providing the positioning holes in this way, it becomes possible to easily position the stacking units, for example, using an assembly device having a base plate with a knock pin protruding therefrom. That is, a knock pin is inserted into the positioning hole, and a plurality of stacking units are stacked on the base plate while the inner peripheral surface of the positioning hole is aligned with the outer peripheral surface of the knock pin. As a result, the positioning holes are overlapped in the stacking direction, and the plurality of stacking units can be stacked in a state where they are positioned relative to each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-196849 A Summary of the Invention [Problem to be solved by the invention]

[0005] When stacking the stack units as described above, there is a concern that the stack units may be deformed due to frictional force generated between the inner circumferential surface of the positioning hole and the outer circumferential surface of the knock pin. In a power generation cell stack, adjacent separators must be kept in an electrically insulated state, so that it is necessary to suppress deformation of the separators in the stack units.

[0006] The present invention is devised to solve these types of problems, and has an object to provide a separator for a fuel cell and a fuel cell stack that allow easy positioning of stack units relative to each other and suppress deformation of the separator. [Means for solving the problem]

[0007] One aspect of the present invention is a fuel cell stack comprising a power generation cell stack in which a plurality of stacking units each consisting of an electrolyte membrane-electrode assembly having electrodes disposed on both sides of an electrolyte membrane and a separator are stacked in a stacking direction, the separator being provided with a positioning portion that positions the stacking units relative to each other when stacked in the stacking direction, and the peripheral portion of the positioning portion of the separator being provided with a rib that protrudes in the separator thickness direction and extends in the separator surface direction.

[0008] Another aspect of the present invention is a separator for a fuel cell that is stacked on an electrolyte membrane-electrode assembly in which electrodes are disposed on both sides of an electrolyte membrane to form a stack unit of a power generation cell stack, in which a positioning portion is provided for positioning the stack units relative to each other by stacking the stack units in the stacking direction, and a rib is provided on the peripheral portion of the positioning portion of the separator, protruding in the thickness direction of the separator and extending in the separator surface direction. Effect of the Invention

[0009] The separator is provided with positioning parts that position the stacking units relative to each other by stacking them in the stacking direction. For example, by stacking a plurality of stacking units while aligning the positioning parts with a guide bar or the like, the positioning parts can be stacked relative to each other in the stacking direction. As a result, the plurality of stacking units can be easily stacked in a state where they are positioned relative to each other.

[0010] In addition, the peripheral portion of the separator positioning portion is provided with a rib that protrudes in the separator thickness direction and extends in the separator surface direction. This increases the rigidity of the peripheral portion of the separator positioning portion, making it less likely to deform. Therefore, for example, when the positioning portion is aligned with the guide bar to overlap the positioning portion as described above, even if friction occurs between the positioning portion and the guide bar, deformation of the separator can be suppressed.

[0011] Therefore, according to the present invention, the stack units can be easily positioned relative to each other, and deformation of the separator can be suppressed. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view of a fuel cell stack according to an embodiment of the present invention. [Diagram 2] 1 is an exploded perspective view of a power generating cell including a separator for a fuel cell according to an embodiment of the present invention. [Diagram 3] FIG. 2 is an explanatory diagram of the MEA side of a separator (first bipolar plate). [Figure 4] 4A is an enlarged view of the peripheral portion of the first positioning portion of FIG. 3, FIG. 4B is an enlarged view of the peripheral portion of the second positioning portion of FIG. 3, and FIG. 4C is an enlarged view of the peripheral portion of the third positioning portion of FIG. 3. [Diagram 5] 13 is a perspective view of a rib provided on the periphery of a third positioning portion of the separator. FIG. [Figure 6] 2 is a schematic plan view of a manufacturing apparatus for manufacturing a power generating cell laminate of a fuel cell stack. FIG. [Figure 7] FIG. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. 6. [Figure 8] 8 is an explanatory diagram showing a state in which a pressure unit is brought close to the mounting table in FIG. 7. FIG. [Figure 9] FIG. 9 is an explanatory diagram showing a state in which a pressure unit is brought even closer to the mounting table in FIG. 8. [Figure 10] 13 is a perspective explanatory view of a peripheral edge portion of a third positioning portion provided with a rib according to a modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A preferred embodiment of a fuel cell separator and a fuel cell stack according to the present invention will be described in detail with reference to the accompanying drawings. In the following drawings, the same reference numerals are used to designate components having the same or similar functions and effects, and repeated description may be omitted.

[0014] A fuel cell stack 16 including a fuel cell separator 28 according to this embodiment shown in FIG. 1 can be mounted on a fuel cell vehicle, such as a fuel cell electric vehicle (not shown), or can be used as a stationary type. The fuel cell stack 16 includes a power generating cell stack 12. The power generating cell stack 12 is formed by stacking a plurality of power generating cells 14 in a stacking direction (arrow A direction). At one end side (arrow A1 side) of the power generating cell stack 12 in the stacking direction, a terminal plate 18a, an insulator 20a, and an end plate 22a are disposed outward in this order. At the other end side (arrow A2 side) of the power generating cell stack 12 in the stacking direction, a terminal plate 18b, an insulator 20b, and an end plate 22b are disposed outward in this order.

[0015] The insulators 20a, 20b are formed of an insulating material such as polycarbonate (PC) or phenol resin. Each of the insulators 20a, 20b may be composed of a plurality of sheets (for example, two sheets) stacked in the stacking direction. Although not shown, a recess that is recessed toward the side away from the power generation cell stack 12 may be formed on the surface of each of the insulators 20a, 20b facing the power generation cell stack 12, and the terminal plates 18a, 18b may be disposed in the recess.

[0016] A connecting bar 24 is disposed between each side of the end plates 22a, 22b. Both ends of each connecting bar 24 are fixed to the inner surface of the end plates 22a, 22b via bolts or the like, and apply a compressive load (clamping load) in the stacking direction to the power generation cell stack 12. The fuel cell stack 16 may be configured to include a housing with the end plates 22a, 22b as end plates, and to house the power generation cell stack 12 and the like in the housing.

[0017] 2, the power generating cell 14 has a resin-framed MEA 26 and a set of separators 28 that sandwich the resin-framed MEA 26. The resin-framed MEA 26 is constructed by surrounding the outer periphery of a membrane electrode assembly (MEA) 30 with a resin frame member 32. The membrane electrode assembly 30 has an electrolyte membrane 34, an anode electrode 36 provided on one surface (the side of the arrow A2) of the electrolyte membrane 34, and a cathode electrode 38 provided on the other surface (the side of the arrow A1) of the electrolyte membrane 34.

[0018] The electrolyte membrane 34 is, for example, a solid polymer electrolyte membrane (cation exchange membrane) such as a thin film of perfluorosulfonic acid containing moisture, and is sandwiched between the anode electrode 36 and the cathode electrode 38. Note that the electrolyte membrane 34 may be an HC (hydrocarbon)-based electrolyte in addition to a fluorine-based electrolyte.

[0019] Each of the anode electrodes 36 has an anode electrode catalyst layer and an anode gas diffusion layer, both of which are not shown. The anode electrode catalyst layer is bonded to one surface (the side of the arrow A2) of the electrolyte membrane 34. The anode gas diffusion layer is laminated on the anode electrode catalyst layer. Each of the cathode electrodes 38 has a cathode electrode catalyst layer and a cathode gas diffusion layer, both of which are not shown. The cathode electrode catalyst layer is bonded to the other surface (the side of the arrow A1) of the electrolyte membrane 34. The cathode gas diffusion layer is laminated on the cathode electrode catalyst layer.

[0020] The anode electrode catalyst layer is formed, for example, by uniformly applying porous carbon particles having a platinum alloy supported on their surfaces to the surface of the anode gas diffusion layer together with an ion-conductive polymer binder, while the cathode electrode catalyst layer is formed, for example, by uniformly applying porous carbon particles having a platinum alloy supported on their surfaces to the surface of the cathode gas diffusion layer together with an ion-conductive polymer binder.

[0021] The cathode gas diffusion layer and the anode gas diffusion layer are formed from a conductive porous sheet such as carbon paper or carbon cloth. A porous layer (not shown) may be provided at least one between the cathode electrode catalyst layer and the cathode gas diffusion layer and between the anode electrode catalyst layer and the anode gas diffusion layer.

[0022] The resin frame member 32 has a frame shape, and for example, its inner peripheral edge is joined to the outer peripheral edge of the membrane electrode assembly 30. By providing the resin frame member 32 on the outer periphery of the membrane electrode assembly 30 in this manner, it becomes possible to reduce the area of ​​the relatively expensive electrolyte membrane 34 required to constitute one power generating cell 14, for example.

[0023] The joining structure between the resin frame member 32 and the membrane electrode assembly 30 is not particularly limited, but may be, for example, such that the inner peripheral edge of the resin frame member 32 is sandwiched between the outer peripheral edge of the cathode gas diffusion layer and the outer peripheral edge of the anode gas diffusion layer. In this case, the inner peripheral edge face of the resin frame member 32 may be close to, abut against, or overlap the outer peripheral edge face of the electrolyte membrane 34.

[0024] Instead of the above-mentioned joining structure, the resin frame member 32 may be constructed by making the outer peripheral edge of the electrolyte membrane 34 protrude outward beyond the cathode gas diffusion layer and the anode gas diffusion layer, and providing frame-shaped films on both sides of the outer peripheral edge of the electrolyte membrane 34. In other words, the resin frame member 32 may be constructed by joining a plurality of stacked frame-shaped films with an adhesive or the like.

[0025] 1 and 2, the oxidant gas inlet manifold 40a, the coolant inlet manifold 42a, and the fuel gas outlet manifold 44b are arranged in the direction of arrow C on the periphery of one end (arrow B1 side) in the long side direction of the power generation cell 14, the end plate 22a, and the insulators 20a, 20b. The fuel gas inlet manifold 44a, the coolant outlet manifold 42b, and the oxidant gas outlet manifold 40b are arranged in the direction of arrow C on the periphery of the other end (arrow B2 side) in the long side direction of the power generation cell 14, the end plate 22a, and the insulators 20a, 20b.

[0026] An oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet manifold 40a. A coolant such as at least one of pure water, ethylene glycol, and oil is supplied to the coolant inlet manifold 42a. A fuel gas such as a hydrogen-containing gas is discharged from the fuel gas outlet manifold 44b. A fuel gas is supplied to the fuel gas inlet manifold 44a. A coolant is discharged from the coolant outlet manifold 42b. An oxidant gas is discharged from the oxidant gas outlet manifold 40b.

[0027] The oxidant gas inlet manifolds 40a provided in each of the power generating cells 14, the end plates 22a, and the insulators 20a, 20b in the power generating cell stack 12 communicate with each other in the stacking direction. That is, the oxidant gas inlet manifold 40a penetrates the end plates 22a, the insulators 20a, 20b, and the power generating cell stack 12 in the stacking direction. Similarly, the coolant inlet manifold 42a, the fuel gas outlet manifold 44b, the fuel gas inlet manifold 44a, the coolant outlet manifold 42b, and the oxidant gas outlet manifold 40b also penetrate the end plates 22a, the insulators 20a, 20b, and the power generating cell stack 12 in the stacking direction.

[0028] In this embodiment, an example is shown in which each power generating cell 14 is provided with one each of the oxidant gas inlet manifold 40a, the coolant inlet manifold 42a, the fuel gas outlet manifold 44b, the fuel gas inlet manifold 44a, the coolant outlet manifold 42b, and the oxidant gas outlet manifold 40b (hereinafter, these are also collectively referred to simply as "manifolds"). However, the number of each manifold provided in each power generating cell 14 is not particularly limited, and may be one or more. Furthermore, the shape and arrangement of each manifold are not limited to those of this embodiment shown in Figs. 1 and 2, and can be set appropriately according to the required specifications.

[0029] 2, separator 28 is rectangular with a pair of long sides facing each other in the direction of arrow C and a pair of short sides facing each other in the direction of arrow B. Separator 28 is formed by integrally joining the outer peripheries of stacked first bipolar plates 46 and second bipolar plates 48 by welding, brazing, crimping, or the like. Each of first bipolar plates 46 and second bipolar plates 48 is formed by pressing a cross section of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, a titanium plate, or a thin metal plate whose metal surface has been subjected to a corrosion-resistant surface treatment into a corrugated shape.

[0030] In addition, the separator 28 is not limited to being formed by joining the first bipolar plate 46 and the second bipolar plate 48, and may be formed from a single metal plate (bipolar plate). In addition, an insulating resin material may be provided on the outer edge of the separator 28.

[0031] The first bipolar plate 46 and the second bipolar plate 48 incorporated into the power generating cell stack 12 as the separator 28 each have an MEA side 46a, 48a which faces the resin framed MEA 26, and a refrigerant side 46b, 48b which is the reverse side.

[0032] 3, the MEA side surface 46a of the first bipolar plate 46 has a plurality of ridges extending linearly in the direction of arrow B. Linear oxidant gas flow paths 50 are provided in grooves between these ridges. The ridges and the oxidant gas flow path 50 may be wavy. The oxidant gas flow path 50 is fluidly connected to the oxidant gas inlet manifold 40a and the oxidant gas outlet manifold 40b, thereby allowing the oxidant gas to flow in the surface direction of the separator 28 (the direction of arrows B and C).

[0033] Furthermore, a metal bead seal 52a protruding toward the resin-framed MEA 26 (FIG. 2) is integrally provided, for example, by press molding, on the MEA side surface 46a of the first bipolar plate 46. Instead of the metal bead seal 52a, a convex elastic seal made of an elastic material such as rubber may be provided on the MEA side surface 46a.

[0034] The metal bead seal 52a of the first bipolar plate 46 wraps around the outer periphery of the oxidant gas flow field 50, the oxidant gas inlet manifold 40a, and the oxidant gas outlet manifold 40b so as to connect these flow fields to one another. The metal bead seal 52a also wraps around the fuel gas inlet manifold 44a, the fuel gas outlet manifold 44b, the coolant inlet manifold 42a, and the coolant outlet manifold 42b individually to prevent the fuel gas and the coolant from flowing into the oxidant gas flow field 50.

[0035] 2, the MEA side surface 48a of the second bipolar plate 48 is provided with a plurality of ridges extending linearly in the direction of arrow B. Linear fuel gas flow channels 54 are provided in the grooves between these ridges. The ridges and the fuel gas flow channels 54 may be wavy. The fuel gas flow channels 54 are fluidly connected to the fuel gas inlet manifold 44a and the fuel gas outlet manifold 44b, thereby allowing the fuel gas to flow in the surface direction of the separator 28 (the direction of arrows B and C).

[0036] Moreover, a metal bead seal 52b protruding toward the resin-framed MEA 26 is integrally provided, for example, by press molding, on the MEA side surface 48a of the second bipolar plate 48. Instead of the metal bead seal 52b, a convex elastic seal made of an elastic material such as rubber may be provided on the MEA side surface 48a.

[0037] The metal bead seal 52b of the second bipolar plate 48 wraps around the outer periphery of the fuel gas flow field 54, the fuel gas inlet manifold 44a, and the fuel gas outlet manifold 44b so as to connect the fuel gas flow field 54, the fuel gas inlet manifold 44a, and the fuel gas outlet manifold 44b to each other. The metal bead seal 52b also wraps around the oxidant gas inlet manifold 40a, the oxidant gas outlet manifold 40b, the coolant inlet manifold 42a, and the coolant outlet manifold 42b individually to prevent the oxidant gas and the coolant from flowing into the fuel gas flow field 54.

[0038] A coolant flow passage 56 is provided between the coolant side 46b of the first bipolar plate 46 and the coolant side 48b of the second bipolar plate 48, which are joined together. The coolant flow passage 56 fluidly communicates with the coolant inlet passage 42a and the coolant outlet passage 42b to allow the coolant to flow in the surface direction of the separator 28 (the direction of arrows B and C).

[0039] The coolant flow field 56 is formed by overlapping the back surface shape of the MEA side surface 46a of the first bipolar plate 46, in which the oxidant gas flow field 50 is formed, with the back surface shape of the MEA side surface 48a of the second bipolar plate 48, in which the fuel gas flow field 54 is formed. In addition, the peripheries of the communication holes on the refrigerant side surfaces 46b, 48b of the first bipolar plate 46 and the second bipolar plate 48 facing each other are joined by welding, brazing, or the like.

[0040] The power generating cell stack 12 is formed by stacking a plurality of stacking units E (FIG. 2) each including, for example, one separator 28 (first bipolar plate 46 and second bipolar plate 48) and one resin-framed MEA 26 (membrane electrode assembly 30) superimposed and joined together. In the stacking unit E, the outer edge of the resin frame member 32 is preliminarily joined to the outer edge of the separator 28 by welding or adhesion. Note that the stacking unit E is not limited to one including one separator 28 and one resin-framed MEA 26 superimposed and joined together. The stacking unit E may be any unit that can finally form the power generating cell stack 12 by stacking a plurality of stacking units E. The stacking unit E may also be formed in a state in which the resin frame member 32 and the separator 28 are not joined together.

[0041] A positioning portion 58 is provided on the separator 28 of the stacking unit E. When stacking a plurality of stacking units E, the positioning portions 58 of the stacking units E are overlapped in the stacking direction, so that the stacking units E are accurately positioned relative to each other. In this embodiment, the positioning portion 58 is a groove (recess) formed by cutting out the edge portion 28a of the separator 28 from the outside toward the inside of the separator 28. The shape of the positioning portion 58 when viewed in the stacking direction is rectangular.

[0042] 3 and 4A to 4C, in this embodiment, the positioning portion 58 has a first positioning portion 58a, a second positioning portion 58b, and a third positioning portion 58c. That is, a total of three positioning portions 58 are provided on one separator 28. As shown in Fig. 3, the first positioning portion 58a is provided in the vicinity of the end portion on the arrow C1 side of the short side on the arrow B1 side of the separator 28.

[0043] The second positioning portion 58b is provided in the vicinity of the end portion on the arrow C2 side of the short side on the arrow B2 side of the separator 28. That is, the first positioning portion 58a and the second positioning portion 58b are disposed at diagonal positions of the separator 28. Note that the first positioning portion 58a and the second positioning portion 58b may be in an opposite positional relationship in the direction of the arrow C.

[0044] The third positioning portion 58c is provided approximately in the center of the long side on the arrow C2 side of the separator 28. In the following, when the first positioning portion 58a, the second positioning portion 58b, and the third positioning portion 58c are not to be distinguished from one another, they are also collectively referred to simply as positioning portion 58.

[0045] As shown in FIG. 4A to FIG. 4C, each of the positioning portions 58 has a first side 110 that is located inside the separator 28 relative to the edge portion 28a (long side and short side) of the separator 28 and that is along the extending direction of the edge portion 28a, and a pair of second sides 112 that extend from both ends of the extending direction of the first side 110 toward the edge portion 28a of the separator 28. That is, as shown in FIG. 4A, the first side 110 of the first positioning portion 58a is located on the arrow B2 side relative to the short side of the separator 28 on the arrow B1 side and along the extending direction of the short side (arrow C direction). The pair of second sides 112 of the first positioning portion 58a extend from both ends of the extending direction (arrow C direction) of the first side 110 toward the arrow B1 side. That is, the second sides 112 of the first positioning portions 58a face each other at an interval in the arrow C direction.

[0046] 4B, the first side 110 of the second positioning portion 58b is closer to the arrow B1 side than the short side on the arrow B2 side of the separator 28 and is aligned along the extension direction (arrow C direction) of the short side. The pair of second sides 112 of the second positioning portion 58b extend from both ends of the extension direction (arrow C direction) of the first side 110 toward the arrow B2 side. In other words, the second sides 112 of the second positioning portion 58b face each other with a gap in between in the arrow C direction.

[0047] 4C, the first side 110 of the third positioning portion 58c is closer to the arrow C1 side than the long side on the arrow C2 side of the separator 28 and is aligned along the extension direction (arrow B direction) of the long side. The pair of second sides 112 of the third positioning portion 58c extend from both ends of the extension direction (arrow B direction) of the first side 110 toward the arrow C2 side. In other words, the second sides 112 of the third positioning portion 58c face each other with a gap in between in the arrow B direction.

[0048] Hereinafter, the length of the first side 110 of the positioning portion 58 is also referred to as the width, and the length of the second side 112 is also referred to as the depth. The arrangement and number of the positioning portions 58 provided for the stacking unit E are not limited to those shown in FIG. 3, and can be set in various ways depending on, for example, the shapes of the separator 28 and the resin-framed MEA 26. In this embodiment, as shown in FIG. 2, the outer edge of the resin frame member 32 in the power generating cell 14 is overlapped with the outer edge of the separator 28. A groove portion 32a is provided in the outer edge of the resin frame member 32 in a portion facing the positioning portion 58 of the separator 28. When viewed in the stacking direction, the size of the groove portion 32a is larger than the size of the positioning portion 58.

[0049] 5, a weld 116 for welding the first bipolar plate 46 and the second bipolar plate 48 is provided along the peripheral edge 114 of the positioning portion 58 of the separator 28. That is, the weld 116 is provided in a line shape extending along the first side 110 and the second side 112 of the positioning portion 58, on the inner side of the separator 28 relative to each of the first side 110 and the second side 112.

[0050] A rib 118 that protrudes in the separator thickness direction (arrow A direction) and extends in the separator surface direction (arrows B and C directions) is provided on the peripheral portion 114 of the positioning portion 58 of the separator 28. In this embodiment, the rib 118 is provided protruding toward the arrow A1 side in the separator thickness direction with respect to both the first bipolar plate 46 and the second bipolar plate 48. In other words, when the separator 28 is viewed from the arrow A2 side, the rib 118 of each of the first bipolar plate 46 and the second bipolar plate 48 has a concave shape that recesses toward the arrow A1 side.

[0051] However, the rib 118 may be provided on at least one of the first bipolar plate 46 and the second bipolar plate 48. The rib 118 may protrude toward the arrow A2 side in the separator thickness direction. That is, when the separator 28 is viewed from the arrow A1 side, the rib 118 may have a concave shape that is recessed toward the arrow A2 side. Furthermore, when the rib 118 is provided on both the first bipolar plate 46 and the second bipolar plate 48, the direction in which the rib 118 provided on the first bipolar plate 46 protrudes and the direction in which the rib 118 provided on the second bipolar plate 48 protrudes may be opposite to each other, although not shown. In this embodiment, the cross-sectional shape of the rib 118 when viewed in the direction of the arrow B is a trapezoid, but is not particularly limited to this. For example, the cross-sectional shape of the rib 118 when viewed in the direction of the arrow B may be a rectangle, a triangle, another polygon, an arc, or the like.

[0052] In this embodiment, the rib 118 has two first ribs 118a and two second ribs 118b. Each of the two first ribs 118a extends from the first side 110 of the positioning portion 58 toward the inside of the separator 28. The extension direction of each first rib 118a is perpendicular to the first side 110. The two first ribs 118a are arranged in parallel with an interval in the extension direction of the first side 110. One of the two second ribs 118b extends from one of the pair of second sides 112 toward the inside of the separator 28. The other of the two second ribs 118b extends from the other of the pair of second sides 112 toward the inside of the separator 28. The extension direction of the second ribs 118b is perpendicular to the second side 112.

[0053] However, it is sufficient that the rib 118 has at least one of the first rib 118a and the second rib 118b. Furthermore, the number and extending direction of each of the first ribs 118a and the second ribs 118b are not particularly limited, and can be set appropriately according to the required specifications.

[0054] Each of the first rib 118a and the second rib 118b is provided so as to avoid the welded portion 116, in other words, it is divided by the welded portion 116 in the middle of the extending direction. Therefore, each of the first rib 118a and the second rib 118b is provided on the positioning portion 58 side of the welded portion 116 (between the welded portion 116 and the positioning portion 58) and on the inside of the separator 28 of the welded portion 116 (opposite the positioning portion 58 across the welded portion 116). Note that the first rib 118a and the second rib 118b may be provided so as to extend crossing the welded portion 116 without avoiding it. Also, only one of the first rib 118a and the second rib 118b (for example, the second rib 118b) may be arranged so as to avoid the welded portion 116, and the other (for example, the first rib 118a) may be provided so as to extend crossing the welded portion 116.

[0055] 1 to 3, a brief description will be given of the operation of the fuel cell stack 16 including the power generation cell stack 12. When generating electricity in the fuel cell stack 16, fuel gas is supplied to the fuel gas inlet passage 44a, oxidant gas is supplied to the oxidant gas inlet passage 40a, and a coolant is supplied to the coolant inlet passage 42a.

[0056] 3, the oxidant gas is introduced into the oxidant gas flow path 50 from the oxidant gas inlet manifold 40a, moves along the oxidant gas flow path 50 in the direction of arrow B, and is supplied to the cathode 38 of the membrane electrode assembly 30. On the other hand, the fuel gas is introduced into the fuel gas flow path 54 from the fuel gas inlet manifold 44a, moves along the fuel gas flow path 54 in the direction of arrow B, and is supplied to the anode 36 of the membrane electrode assembly 30, as shown in FIG.

[0057] Therefore, in each electrolyte membrane electrode assembly 30, the oxidant gas supplied to the cathode electrode 38 and the fuel gas supplied to the anode electrode 36 are consumed by electrochemical reactions in the cathode electrode catalyst layer and the anode electrode catalyst layer, generating electricity.

[0058] The oxidant gas (oxidant exhaust gas) that is not consumed in the electrochemical reaction flows from the oxidant gas flow path 50 into the oxidant gas outlet manifold 40b, flows through the oxidant gas outlet manifold 40b in the direction of arrow A and is discharged from the fuel cell stack 16. Similarly, the fuel gas (fuel exhaust gas) that is not consumed in the electrochemical reaction flows from the fuel gas flow path 54 into the fuel gas outlet manifold 44b, flows through the fuel gas outlet manifold 44b in the direction of arrow A and is discharged from the fuel cell stack 16.

[0059] The cooling medium is introduced into the cooling medium flow path 56 through the cooling medium inlet manifold 42a and moves along the cooling medium flow path 56 in the direction of arrow B, exchanging heat with the membrane electrode assembly 30. After heat exchange, the cooling medium flows into the cooling medium outlet manifold 42b, flows through the cooling medium outlet manifold 42b in the direction of arrow A, and is discharged from the fuel cell stack 16.

[0060] An example of a manufacturing apparatus 10 for manufacturing a power generating cell stack 12 by stacking a plurality of stacking units E while overlapping the positioning portions 58 will be described below with main reference to Figs. 6 to 9. The manufacturing apparatus 10 can be applied, for example, to a case where a plurality of stacking units E are stacked in the stacking direction indicated by the arrow X to obtain the power generating cell stack 12 of Fig. 1. In this embodiment, the plurality of stacking units E are stacked from the lower side (arrow X2 side) toward the upper side (arrow X1 side). That is, the stacking direction of the stacking units E in the manufacturing apparatus 10 is along the vertical direction (gravity direction).

[0061] The manufacturing apparatus 10 includes a mounting table 60, a pressure unit 62, a drive mechanism 64, a guide bar 66, and a support mechanism 68. Note that the pressure unit 62 and the drive mechanism 64 are not shown in the manufacturing apparatus 10 in Fig. 6. In addition, in order to explain the positional relationship between the positioning unit 58 and the rib 118 and the guide bar 66 in the stacking unit E in Fig. 6, the positioning unit 58 and the rib 118 are shown for convenience, regardless of whether the upper surface of the stacking unit E is a separator 28 or not.

[0062] The mounting table 60 has a mounting surface 70 on which the stacking units E are stacked in a stacking direction (the direction of the arrow X). The pressure unit 62 is driven by a drive mechanism 64, so that it can approach or move away from the mounting table 60 in the stacking direction.

[0063] A guide post 72 extending in the stacking direction is protruded outward from the mounting surface 70 of the mounting table 60. The pressure unit 62 is also provided with an engagement portion 74 that engages with the guide post 72 when the pressure unit 62 approaches the mounting table 60 to a predetermined distance, as shown in Figs. 8 and 9. In this embodiment, the engagement portion 74 is a through hole provided in the pressure unit 62, and engages with the guide post 72 by the guide post 72 being slidably inserted therethrough. With the engagement portion 74 engaged with the guide post 72, the pressure unit 62 approaches or moves away from the mounting table 60, thereby guiding the movement direction of the pressure unit 62 to be along the stacking direction.

[0064] Further, the pressure applying unit 62 is provided with a pressure applying surface 76 and a contact portion 78. As shown in Fig. 8 and Fig. 9, when the pressure applying unit 62 approaches the mounting table 60, the pressure applying surface 76 contacts the stacking unit E stacked on the mounting surface 70. When the pressure applying unit 62 approaches the mounting table 60, the contact portion 78 contacts the upper surface of the guide bar 66.

[0065] The guide bar 66 protrudes from the mounting surface 70 of the mounting table 60 in the stacking direction, and is movable in the stacking direction relative to the mounting surface 70. Therefore, by bringing the pressing unit 62 further closer to the mounting table 60 with the abutting portion 78 of the pressing unit 62 in contact with the upper surface of the guide bar 66, it is possible to move the guide bar 66 together with the pressing unit 62 at the same speed.

[0066] In this embodiment, the guide bar 66 is a square bar extending along the stacking direction. Hereinafter, the side of the guide bar 66 toward the mounting table 60 in the extending direction is also referred to as the base end side (arrow X2 side), and the side opposite to the mounting table 60 is also referred to as the tip end side (arrow X1 side). The guide bar 66 is provided corresponding to the number and arrangement of the positioning parts 58 provided in the stacking unit E to be stacked on the mounting surface 70. For this reason, in this embodiment, as shown in FIG. 6, three guide bars 66 corresponding to the first positioning part 58a, the second positioning part 58b, and the third positioning part 58c of the stacking unit E are provided on the mounting table 60. These three guide bars 66 can be configured similarly to each other except for their arrangement relative to the mounting surface 70.

[0067] As shown in Figs. 7 to 9, specifically, the guide bar 66 has a main body portion 80, a narrow portion 82, and a stopper portion 84. The main body portion 80, the narrow portion 82, and the stopper portion 84 are arranged in this order from the tip end side to the base end side in the extension direction of the guide bar 66. Although not shown in the drawings, the narrow portion 82 and the stopper portion 84 are separably integrated. In the extension direction of the main body portion 80, most of the tip side of the main body portion 80 protrudes from the mounting surface 70 in the stacking direction. The length by which the main body portion 80 protrudes from the mounting surface 70 is longer than the length in the stacking direction of a predetermined number of stacking units E that constitute the power generation cell stack 12 when the stacked units are stacked on the mounting surface 70.

[0068] The main body 80 also has an insertion portion 86 and an exposed portion 88. When the stacking unit E is stacked on the placement surface 70, the insertion portion 86 is inserted into the positioning portion 58 of the stacking unit E. When the insertion portion 86 is inserted into the positioning portion 58, the exposed portion 88 is disposed outside the positioning portion 58 as viewed in the stacking direction. That is, the shape of the main body 80 as viewed in the stacking direction corresponds to the shape of the positioning portion 58 as viewed in the stacking direction. In this embodiment, the shape of the guide bar 66 as viewed in the stacking direction is rectangular, and the length of the side along the width direction of the positioning portion 58 is slightly shorter than the width of the positioning portion 58. Also, the length of the side along the depth direction of the positioning portion 58 is longer than the depth of the positioning portion 58.

[0069] With the insertion portion 86 inserted into the positioning portion 58 as described above, the stacking unit E can be stacked on the mounting surface 70 while aligning the positioning portion 58 along the guide bar 66, thereby guiding the stacking unit E to a predetermined stacking position on the mounting surface 70. The multiple stacking units E stacked on the mounting surface 70 in this manner have their positioning portions 58 overlapped in the stacking direction via the guide bar 66. This makes it possible to stack the multiple stacking units E in a state where they are positioned relative to one another.

[0070] Although not shown, the outer dimensions of a cross section perpendicular to the extending direction of the narrow portion 82 are smaller than the above-mentioned outer dimensions of the main body portion 80 and the stopper portion 84. Therefore, a first step portion 90 is formed between the main body portion 80 and the narrow portion 82. In addition, a second step portion 92 is formed between the narrow portion 82 and the stopper portion 84. In this embodiment, the above-mentioned outer dimensions of the main body portion 80 and the stopper portion 84 are the same, but may be different from each other.

[0071] The base end side of the main body 80, the narrow portion 82, and the stopper portion 84 are inserted into a support hole 94 formed in the mounting table 60 along the stacking direction, and are movable within the support hole 94 along the stacking direction. Although not shown, the dimensions of a cross section perpendicular to the extension direction of the support hole 94 are the same as or slightly larger than the above-mentioned outer dimensions of the main body 80 and the stopper portion 84. Therefore, the main body 80 and the stopper portion 84 are slidable within the support hole 94 along the stacking direction, and the extension direction of the guide bar 66 is maintained in a state along the stacking direction.

[0072] A throttle portion 96 is provided in the support hole 94 between the first step portion 90 and the second step portion 92 of the guide bar 66 inserted into the support hole 94. When viewed in the extending direction of the support hole 94, the throttle portion 96 protrudes from the inner wall surface of the support hole 94 toward the center of the support hole 94, and a through hole 96a through which the narrow portion 82 is inserted is formed in the center. Although not shown, the cross-sectional dimension of the through hole 96a in the direction perpendicular to the extending direction of the support hole 94 is smaller than the above-mentioned outer dimensions of the main body portion 80 and the stopper portion 84 and slightly larger than the above-mentioned outer dimensions of the narrow portion 82.

[0073] An end face 96b on the tip side of the narrowed portion 96 faces the first step portion 90 with a gap therebetween. An elastic member 98 is disposed between the end faces 96b on the tip side of the narrowed portion 96 and the first step portion 90. In this embodiment, the elastic member 98 is a coil spring, and the direction of expansion and contraction thereof is along the stacking direction. The narrowed portion 82 is inserted into the inner diameter side of the elastic member 98. The elastic member 98 resiliently biases the guide bar 66 in a direction protruding from the mounting surface 70.

[0074] An end face 96c on the base end side of the narrowed portion 96 faces the second step portion 92 so as to be able to abut against it. As described above, the guide bar 66, which is resiliently biased by the elastic member 98, is restricted from moving any further in the direction protruding from the mounting surface 70 by the abutment between the end face 96c on the base end side of the narrowed portion 96 and the second step portion 92 (FIG. 7). As shown in FIGS. 8 and 9, the elastic member 98 is elastically deformed in the direction in which it is compressed between the end face 96b on the tip end side of the narrowed portion 96 and the first step portion 90, so that the guide bar 66 is able to move in the direction of entering the mounting surface 70. At this time, the second step portion 92 is separated from the end face 96c on the base end side of the narrowed portion 96.

[0075] A support bar 100 is provided near the guide bar 66 of the mounting table 60, protruding along the guide bar 66 in the stacking direction. The support bar 100 is fixed to the mounting table 60, and a recess 102 (FIG. 6) is formed in which the exposed portion 88 of the guide bar 66 is accommodated so as to be slidable in the stacking direction. The length of protrusion of the support bar 100 from the mounting surface 70 is shorter than the length in the stacking direction of the multiple stack units E compressed on the mounting surface 70 (FIG. 9), as will be described later. The support bar 100 and the support hole 94 of the mounting table 60 support the guide bar 66 movably in the stacking direction, thereby constituting a support mechanism 68 capable of maintaining the extension direction of the guide bar 66 along the stacking direction.

[0076] Hereinafter, an example of a manufacturing method for obtaining the power generating cell stack 12 of FIG. 1 by stacking a plurality of stacking units E using the manufacturing apparatus 10 of FIGS. 6 to 9 will be described. In the manufacturing method of the power generating cell stack 12, a stacking step is first performed. In the stacking step, as shown in FIG. 7, the pressurizing unit 62 is moved to a position away from the mounting table 60 by the driving mechanism 64. As a result, the contact portion 78 of the pressurizing unit 62 is also separated from the guide bar 66. Therefore, the guide bar 66 is disposed at a position where the second step portion 92 abuts against the end face 96c on the base end side of the narrowed portion 96 with respect to the support hole 94 of the mounting table 60 due to the elastic force of the elastic member 98. In other words, the protruding length of the main body portion 80 from the mounting surface 70 becomes maximum.

[0077] In this state, a predetermined number of stacking units E that constitute the power generating cell stack 12 are stacked on the mounting surface 70. Specifically, the insertion portions 86 of the guide bar 66 are inserted in the stacking direction into the positioning portions 58 of the stacking units E. Then, the stacking unit E is moved from above to below while aligning the positioning portions 58 with the insertion portions 86. This movement may be performed by dropping the stacking unit E onto the mounting surface 70 with the insertion portions 86 inserted into the positioning portions 58.

[0078] As described above, the stacking unit E is guided to the stacking position by aligning the positioning portion 58 with the insertion portion 86. In this manner, by stacking the multiple stacking units E while guiding them to the stacking position, the positioning portion 58 of each stacking unit E is positioned in a state where it is overlapped in the stacking direction via the guide bar 66. That is, a predetermined number of stacking units E can be stacked on the placement surface 70 in a state where positional deviation between the stacking units E is suppressed.

[0079] Next, a compression step is performed. In the compression step, the driving mechanism 64 moves the pressure unit 62 closer to the mounting table 60 on which the plurality of laminated units E have been laminated in the lamination step. As a result, as shown in FIG. 8, the pressure surface 76 of the pressure unit 62 comes into contact with the laminated units E. Also, the contact portion 78 of the pressure unit 62 comes into contact with the tip side of the guide bar 66. From this state, as shown in FIG. 9, the pressure unit 62 is further moved closer to the mounting table 60, thereby compressing the plurality of laminated units E between the mounting surface 70 of the mounting table 60 and the pressure surface 76 of the pressure unit 62.

[0080] At this time, the guide bar 66 is also pressed against the pressure applying portion 62 via the contact portion 78. As a result, the guide bar 66 moves in a direction to enter the inside of the support hole 94 of the mounting table 60 against the elastic force of the elastic member 98. That is, in the compression step, the guide bar 66, with the insertion portion 86 aligned with the positioning portion 58, is moved in the same direction as the movement direction of the pressure applying portion 62, compressing the multiple stacking units E.

[0081] In the compression step, the timing at which the pressurizing surface 76 contacts the laminate unit E may be the same as or earlier than the timing at which the contact portion 78 contacts the tip side of the guide bar 66. For example, it is possible to adjust the timing at which the pressurizing surface 76 contacts the laminate unit E and the timing at which the contact portion 78 contacts the guide bar 66 by adjusting the relative positions of the pressurizing surface 76 and the contact portion 78 in the stacking direction, or by adjusting the protruding length of the main body portion 80 of the guide bar 66 from the mounting surface 70. Therefore, in the compression step, it is possible to adjust the relationship between the timing at which the laminate unit E is compressed and starts to move and the timing at which the guide bar 66 starts to move.

[0082] Next, for example, a fixing mechanism (not shown) is used to maintain the plurality of stacking units E in a compressed state in a compression step. This makes it possible to obtain a power generating cell stack 12 in which a compressive load is applied while the stacking units E are positioned relative to one another.

[0083] The magnitude of the compressive load applied to the plurality of stacking units E in the compression step can be set to various values ​​as necessary. The compression step may be performed multiple times with a release step in between. In the release step, the driving mechanism 64 moves the pressure unit 62 in a direction away from the mounting table 60 to reduce or zero the compressive load. This makes it possible to perform, for example, an aging process for promoting initial creep on the plurality of stacking units E.

[0084] From the above, the separator 28 according to this embodiment is provided with positioning sections 58 that position the stacking units E relative to each other by stacking them in the stacking direction. For this reason, for example, by using the manufacturing apparatus 10, the positioning sections 58 can be stacked relative to each other in the stacking direction by stacking a plurality of stacking units E on the mounting table 60 while aligning the positioning sections 58 along the guide bar 66 or the like. This allows the plurality of stacking units E to be easily stacked in a state where they are positioned relative to each other.

[0085] In addition, a rib 118 that protrudes in the separator thickness direction and extends in the separator surface direction is provided on the peripheral portion 114 of the positioning portion 58 of the separator 28. This increases the rigidity of the peripheral portion 114 of the positioning portion 58 of the separator 28, making it less likely to deform. For this reason, for example, when the positioning portion 58 is aligned with the guide bar 66 to overlap the positioning portions 58 as described above, even if friction occurs between the positioning portion 58 and the guide bar 66, deformation of the separator 28 can be suppressed.

[0086] Therefore, in the separator 28 according to this embodiment and the fuel cell stack 16 including the separator 28, the stacking units E can be easily positioned relative to each other, and deformation of the separator 28 can be suppressed.

[0087] Furthermore, in the above embodiment, when the stacked stack units E are compressed between the mounting table 60 and the pressure unit 62, the guide bar 66 is aligned with the positioning portion 58 to maintain the relative positions of the stack units E. This makes it possible to compress the stack units E in the stacking direction while effectively preventing the stack units E from shifting from their relative positions. In this way, when a compressive force is applied to the stack units E with the guide bar 66 aligned with the positioning portion 58, friction and the like generated between the positioning portion 58 and the guide bar 66 makes it easier for bending stress to occur in the peripheral portion 114 of the positioning portion 58.

[0088] Even in this case, in the separator 28 according to this embodiment, the rigidity of the peripheral portion 114 of the positioning portion 58 is increased by the rib 118, so that deformation of the peripheral portion 114 of the positioning portion 58 can be effectively suppressed. In other words, it is possible to obtain the power generating cell stack 12 by applying a compressive load to the multiple stacking units E while suppressing misalignment of the stacking units E and deformation of the separator 28.

[0089] In the fuel cell stack 16 according to the above embodiment, the positioning portion 58 is a groove in the shape of an edge portion 28a of the separator 28 cut from the outside toward the inside of the separator 28. In this case, a plurality of stacking units E can be easily positioned relative to one another with a simple configuration in which the insertion portion 86 of the rod-shaped guide bar 66 is inserted into the groove-shaped positioning portion 58. In addition, because the positioning portion 58 is groove-shaped, it is easier to increase the rigidity of the peripheral portion 114 of the positioning portion 58 than, for example, when the positioning portion 58 is a convex portion (not shown) that protrudes outward in the separator surface direction from the edge portion 28a of the separator 28.

[0090] The positioning portion 58 may be a protrusion that protrudes outward from the edge 28a of the separator 28 in the separator surface direction. In this case, the edge of the protrusion may be provided with a rib 118. The guide bar 66 may be formed with a groove (not shown) that extends along the stacking direction. With the positioning portion 58 inserted into this groove, the stacking unit E is stacked on the mounting surface, thereby guiding the stacking unit E to the stacking position. Although not shown, the positioning portion 58 may be a through hole that penetrates the separator 28 in the thickness direction.

[0091] Furthermore, the shape of positioning portion 58 as viewed in the stacking direction is not limited to a rectangle having first side 110 and second side 112, and may be, for example, an arc shape or a polygon other than a rectangle. Furthermore, when the shape of positioning portion 58 as viewed in the stacking direction is a polygon, the corners may be rounded.

[0092] In the fuel cell stack 16 according to the embodiment described above, the positioning portion 58 has a first side 110 that is located on the inside of the separator 28 relative to the edge 28a of the separator 28 and that is aligned with the extending direction of the edge 28a, and a pair of second sides 112 that extend from both ends of the first side 110 in the extending direction toward the edge 28a of the separator 28, and the rib 118 has at least one of a first rib 118a that extends from the first side 110 toward the inside of the separator 28 and a second rib 118b that extends from the second side 112 toward the inside of the separator 28. By configuring the rib 118 in this way, it is possible to effectively increase the rigidity of the peripheral portion 114 of the positioning portion 58 and suppress deformation of the separator 28.

[0093] In the fuel cell stack 16 according to the above embodiment, the separator 28 is a joint of a stacked first bipolar plate 46 and a second bipolar plate 48, and a welding portion 116 for welding the first bipolar plate 46 and the second bipolar plate 48 is provided along the peripheral portion 114 of the positioning portion 58, and a rib 118 is provided on at least one of the first bipolar plate 46 and the second bipolar plate 48.

[0094] In this way, even when the separator 28 is a joint of the first bipolar plate 46 and the second bipolar plate 48, the provision of ribs 118 on the peripheral portion 114 of the positioning portion 58 to increase rigidity can suppress deformation of the separator 28. Furthermore, the provision of welded portions 116 on the peripheral portion 114 of the positioning portion 58 can suppress deformation of the first bipolar plate 46 and the second bipolar plate 48 in a direction separating them from each other. Note that the welded portions 116 do not necessarily have to be provided on the peripheral portion 114 of the positioning portion 58.

[0095] In the fuel cell stack 16 according to the above embodiment, the ribs 118 are provided on the inside of the separator 28 relative to the welded portion 116, excluding the welded portion 116, and between the welded portion 116 and the positioning portion 58. In general, the first bipolar plate 46 and the second bipolar plate 48 are joined to form the separator 28 after the rib 118 is provided on at least one of them. For this reason, the process of forming the welded portion 116 is facilitated by providing the rib 118 in advance, avoiding the portion where the welded portion 116 of the peripheral portion 114 of the positioning portion 58 is to be formed. In addition, since the welded portion 116 can be formed well, the first bipolar plate 46 and the second bipolar plate 48 can be firmly joined to effectively suppress deformation of the separator 28.

[0096] In the fuel cell stack 16 according to the above embodiment, the separator 28 is rectangular having a pair of opposing long sides and a pair of opposing short sides, and the positioning portion 58 has a first positioning portion 58a provided on one of the pair of short sides of the separator 28, a second positioning portion 58b provided on the other of the pair of short sides, and a third positioning portion 58c provided on one of the pair of long sides.

[0097] In the fuel cell stack 16 according to the above embodiment, the first positioning portion 58a and the second positioning portion 58b are disposed at diagonal positions of the separator 28, and the third positioning portion 58c is disposed in the center of the long side.

[0098] By providing the positioning portion 58 as described above, it is possible to effectively prevent the laminate units E from being misaligned relative to one another, and also to effectively prevent the separators 28 from being deformed.

[0099] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention.

[0100] 4A to 5, etc., in the above embodiment, the second rib 118b extends from the second side 112 of the positioning portion 58 toward the inside of the separator 28 in a direction perpendicular to the second side 112. Also, the second rib 118b is divided midway in the extending direction by the welded portion 116, so that the second rib 118b is provided on both the side closer to the positioning portion 58 than the welded portion 116 and the side closer to the inside of the separator 28 than the welded portion 116.

[0101] However, as shown in FIG. 10, for example, the second rib 118b may be composed of only a portion provided between the welded portion 116 and the positioning portion 58. In this case, the rib 118 may further include a third rib 118c in addition to the first rib 118a and the second rib 118b. The third rib 118c is provided on the peripheral portion 114 of the positioning portion 58, on the opposite side of the positioning portion 58 (the second rib 118b) across the welded portion 116. The third rib 118c extends from the edge portion 28a of the separator 28 toward the inside of the separator 28 in a direction perpendicular to the edge portion 28a of the separator 28 (direction along the welded portion 116). In the extending direction of the third rib 118c, an end portion 118ce on the opposite side to the edge portion 28a of the separator 28 faces the second rib 118b across the welded portion 116.

[0102] By forming the rib 118 in the above-described shape shown in Fig. 10, the rib 118 can be formed more easily than when the rib 118 is interrupted midway in the extending direction by the welded portion 116, as in the case of the second rib 118b of the rib 118 shown in Figs. 4A to 5. In addition, by providing the third rib 118c extending in a direction different from that of the second rib 118b, the rigidity of the peripheral portion 114 of the positioning portion 58 can be effectively increased, and deformation of the separator 28 can be suppressed. [Explanation of symbols]

[0103] 10... Manufacturing device 12... Power generating cell stack 28...Separator 28a...Edge 30...Electrolyte membrane / electrode structure 34...Electrolyte membrane 36: Anode electrode 38: Cathode electrode 58... Positioning portion 58a... First positioning portion 58b...Second positioning portion 58c...Third positioning portion 110...First side 112...Second side 114...periphery 116...weld 118...Rib 118a...First rib 118b...2nd rib 118c...3rd rib E…Layer unit

Claims

1. A fuel cell stack including a power generation cell laminate in which a plurality of laminate units each including a membrane electrode assembly having electrodes disposed on both sides of an electrolyte membrane and a separator are laminated in a stacking direction, The separator is provided with a positioning portion that positions the stacking units relative to each other by being stacked in the stacking direction, the positioning portion is a groove formed by cutting an edge portion of the separator from the outside toward the inside of the separator, or a through hole penetrating the separator in a thickness direction, a rib is provided on a peripheral edge of the positioning portion of the separator, the rib protruding in a thickness direction of the separator and extending in a surface direction of the separator; A fuel cell stack, wherein the ribs are arranged at intervals so as to surround the positioning portion.

2. A fuel cell stack including a power generation cell laminate in which a plurality of laminate units each including a membrane electrode assembly having electrodes disposed on both sides of an electrolyte membrane and a separator are laminated in a stacking direction, The separator is provided with a positioning portion that positions the stacking units relative to each other by being stacked in the stacking direction, a rib is provided on a peripheral edge of the positioning portion of the separator, the rib protruding in a thickness direction of the separator and extending in a surface direction of the separator; A fuel cell stack, wherein the positioning portion is a groove formed by cutting an edge of the separator from an outer side toward an inner side of the separator.

3. 3. The fuel cell stack according to claim 2, the positioning portion has a first side along an extension direction of the edge portion, the first side being located on the inner side of the separator than the edge portion of the separator, and a pair of second sides extending from both ends of the first side in the extension direction toward the edge portion of the separator, A fuel cell stack, wherein the rib includes at least one of a first rib extending from the first side toward the inside of the separator and a second rib extending from the second side toward the inside of the separator.

4. The fuel cell stack according to any one of claims 1 to 3, the separator is a composite of a first bipolar plate and a second bipolar plate stacked together, a welding portion for welding the first bipolar plate and the second bipolar plate to each other along the peripheral edge of the positioning portion; The rib is provided on at least one of the first bipolar plate and the second bipolar plate.

5. 5. The fuel cell stack according to claim 4, a rib provided on a side of the positioning portion excluding the welded portion and on an inner side of the separator relative to the welded portion, the rib being provided on the side of the positioning portion excluding the welded portion;

6. The fuel cell stack according to any one of claims 1 to 5, the separator has a rectangular shape having a pair of long sides opposed to each other and a pair of short sides opposed to each other, A fuel cell stack, wherein the positioning portion includes a first positioning portion provided on one of the pair of short sides of the separator, a second positioning portion provided on the other of the pair of short sides, and a third positioning portion provided on one of the pair of long sides.

7. 7. The fuel cell stack according to claim 6, the first positioning portion and the second positioning portion are disposed at diagonal positions of the separator, The third positioning portion is a fuel cell stack disposed in the center of the long side.

8. A separator for a fuel cell is laminated on a membrane electrode assembly having electrodes disposed on both sides of an electrolyte membrane to form a stacking unit of a power generation cell stack, a positioning portion is provided for positioning the stacking units relative to each other by stacking the stacking units in a stacking direction; the positioning portion is a groove formed by cutting an edge portion of the separator from the outside toward the inside of the separator, or a through hole penetrating the separator in a thickness direction, a rib is provided on a peripheral edge of the positioning portion of the separator, the rib protruding in a thickness direction of the separator and extending in a surface direction of the separator; The ribs are arranged at intervals so as to surround the positioning portion. A separator for fuel cells.

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