Fuel cell stack and fuel cell separator

Abstract

To provide a fuel cell stack that can suppress side flows of a cooling medium while suppressing side flows of a reactant gas.SOLUTION: A fuel cell stack is formed by stacking a plurality of unit cells 10, each of which includes a power generation portion 11, a frame member 20 provided around the power generation portion to hold the power generation portion, and an anode-side separator 30 and a cathode-side separator 40 sandwiching the power generation portion and the frame member. Cooling channels 35, 45 through which a coolant flows are provided on opposite surfaces 30b, 40b of the anode-side separator and the cathode-side separator. A gasket 50 is provided between the anode-side separator 30 of a unit cell 10A and the cathode-side separator 40 of a unit cell 10B. The anode-side separator and the cathode-side separator are respectively provided with a first protrusion 60 and a second protrusion 70 located between the cooling channel and the gasket. Back surfaces of the first protrusion and the second protrusion have flat surfaces 62, 72 that abut against the frame member.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a fuel cell stack and a separator for a fuel cell. [Background technology]

[0002] Patent Document 1 describes a fuel cell stack. The fuel cell stack described in Patent Document 1 is formed by stacking multiple unit cells. Each unit cell includes a power generation unit, a frame member that surrounds the power generation unit and holds the power generation unit, and a first separator and a second separator that sandwich the power generation unit and the frame member. The first separator and the second separator have groove channels through which a first reactant gas flows and groove channels through which a second reactant gas flows, respectively, on their opposing surfaces that face the power generation unit. The first separator and the second separator have groove channels through which a coolant flows on their opposite surfaces that face the opposing surfaces.

[0003] The first separator is provided with a first protrusion that protrudes toward the second separator of another adjacent unit cell in the stacking direction of the unit cells, and the second separator is provided with a second protrusion that protrudes toward the first protrusion of the first separator of another adjacent unit cell in the stacking direction and abuts against the first protrusion.

[0004] The first convex portion and the second convex portion are arranged side by side in the extending direction of the groove flow path, outside the outermost part of the groove flow path in a direction (hereinafter referred to as the width direction) perpendicular to both the extending direction of the groove flow path and the stacking direction.

[0005] The first separator and the second separator are formed by press-forming a metal plate material. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-123116 Summary of the Invention [Problem to be solved by the invention]

[0007] Because the first separator and the second separator are formed by press-forming a metal plate, recesses are formed on the backside of the first convex portion of the first separator and the backside of the second convex portion of the second separator. This can lead to a risk of so-called bystander flow of the reactant gas, in which the reactant gas flowing through the groove flow channel flows into the recesses through the gap between the frame member and the separator. As a result, the amount of reactant gas supplied to the power generation unit is reduced, resulting in a decrease in power generation efficiency. Therefore, it is necessary to suppress bystander flow of the coolant while also suppressing bystander flow of the reactant gas. [Means for solving the problem]

[0008] A fuel cell stack for solving the above problems is a fuel cell stack formed by stacking a plurality of unit cells, each unit cell including a power generation section, a frame member provided around the power generation section to hold the power generation section, and a first separator and a second separator that sandwich the power generation section and the frame member, wherein a first groove flow path and a second groove flow path through which a first reactant gas and a second reactant gas supplied to the power generation section flow, respectively, are provided on opposing surfaces of the first separator and the second separator that face the power generation section, and a cooling medium that cools the power generation section flows on opposing surfaces of the first separator and the second separator that face the opposing surfaces. a cooling flow path that is formed between the first separator and the second separator of another unit cell stacked on the first separator; a gasket that surrounds the cooling flow path and seals the first separator and the second separator is provided between the first separator and the second separator of another unit cell; a first protrusion and a second protrusion that are positioned between the cooling flow path and the gasket and protrude so as to abut against each other to prevent the cooling medium from flowing outside the cooling flow path; and a back surface of at least one of the first protrusion and the second protrusion has a flat surface that abuts against the frame member.

[0009] With this configuration, the first protrusion of the first separator and the second protrusion of the second separator come into contact with each other, preventing the cooling medium from flowing outside the cooling flow path, i.e., preventing the cooling medium from flowing sideways, thereby enabling the power generation section to be effectively cooled by the cooling medium.

[0010] Furthermore, with the above configuration, the flat portion provided on the back surface of at least one of the first protrusion and the second protrusion abuts against the frame member, thereby preventing the reactant gas from flowing outside the groove flow path between the frame member and the separator, i.e., preventing the reactant gas from flowing sideways.

[0011] Therefore, it is possible to suppress the side flow of the reaction gas while suppressing the side flow of the cooling medium. Furthermore, a fuel cell separator for solving the above problem is a fuel cell separator that is arranged opposite a power generation section of the fuel cell and a frame member that is provided around the power generation section and holds the power generation section, and the opposing surface that faces the power generation section is provided with a groove flow path through which a reaction gas supplied to the power generation section flows, and the opposite surface that is the surface opposite the opposing surface is provided with a cooling flow path through which a cooling medium that cools the power generation section flows, and the opposite surface is provided with an attachment portion that surrounds the cooling flow path and to which a gasket that seals between the separator and other separators stacked on the separator is attached, and the opposite surface is provided with a protrusion that is located between the cooling flow path and the gasket and protrudes so as to abut against the other separator, thereby preventing the cooling medium from flowing outside the cooling flow path, and the back surface of the protrusion has a flat portion that abuts against the frame member.

[0012] With this configuration, the protrusions of one separator come into contact with the protrusions of another separator stacked on top of the separator, preventing the cooling medium from flowing outside the cooling flow path, i.e., preventing sideways flow of the cooling medium, thereby enabling the power generation section to be effectively cooled by the cooling medium.

[0013] Furthermore, with the above configuration, the flat portion provided on the back surface of the protrusion abuts against the frame member, thereby preventing the reactant gas from flowing outside the groove flow path through the gap between the frame member and the separator, i.e., preventing the reactant gas from flowing to the side.

[0014] Therefore, it is possible to suppress the side flow of the reaction gas while suppressing the side flow of the cooling medium. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is an exploded perspective view of a fuel cell stack according to one embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the unit cell of FIG. [Figure 3] FIG. 3 is a plan view of the anode-side separator with the gasket attached thereto. [Figure 4] FIG. 4 is a bottom view of the anode-side separator of FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. [Figure 6] FIG. 6 is an enlarged plan view showing the main part of FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. [Figure 8] FIG. 8 is a plan view showing a modified example of the anode-side separator. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of a fuel cell stack and a separator for a fuel cell will be described with reference to FIGS. In each drawing, for the sake of convenience, some components are shown exaggerated or simplified, and the dimensional proportions of each component may differ from the actual proportions.

[0017] As shown in Fig. 1, the fuel cell stack is formed by stacking a plurality of unit cells 10. Note that Fig. 1 shows two unit cells 10A and 10B out of the plurality of unit cells 10 that make up the fuel cell stack.

[0018] <Single cell 10> 2, the unit cell 10 includes a membrane electrode assembly (hereinafter referred to as the power generation section 11), a frame member 20 that is provided around the power generation section 11 and holds the power generation section 11, and an anode-side separator 30 and a cathode-side separator 40 that sandwich the power generation section 11 and the frame member 20. The unit cell 10 of this embodiment has a rectangular plate shape as a whole.

[0019] In the following description, the stacking direction of the multiple unit cells 10 will be referred to as a first direction X. The short side direction and long side direction of the unit cells 10 will be referred to as a second direction Y and a third direction Z, respectively. The first direction X, the second direction Y, and the third direction Z form an orthogonal coordinate system.

[0020] 1 and 2, the unit cell 10 has supply-side manifolds 111, 112, and 113 for respectively supplying cooling water, fuel gas, and oxidizing gas into the unit cell 10. The unit cell 10 also has discharge-side manifolds 115, 116, and 117 for respectively discharging the cooling water, fuel gas, and oxidizing gas inside the unit cell 10 to the outside.

[0021] The supply side manifolds 111, 112, and 113 and the discharge side manifolds 115, 116, and 117 penetrate the unit cell 10 in the first direction X. The supply-side manifold 111 is provided on one side of the unit cell 10 in the second direction Y (the lower left side in FIGS. 1 and 2).

[0022] The discharge manifold 115 is provided on the other side of the unit cell 10 in the second direction Y (upper right side in FIGS. 1 and 2). The supply-side manifold 113 and the discharge-side manifold 116 are provided on one side (the lower right side in FIGS. 1 and 2) of the unit cell 10 in the third direction Z. The supply-side manifold 113 and the discharge-side manifold 116 are arranged in sequence at intervals from each other in the second direction Y.

[0023] The supply-side manifold 112 and the discharge-side manifold 117 are provided on the other side (upper left side in FIGS. 1 and 2) of the unit cell 10 in the third direction Z. The supply-side manifold 112 and the discharge-side manifold 117 are lined up in sequence at intervals from each other in the second direction Y.

[0024] <Power Generation Section 11> As shown in FIG. 2, the power generating section 11 has a solid polymer electrolyte membrane (hereinafter referred to as electrolyte membrane), and an anode electrode and a cathode electrode provided on both sides of the electrolyte membrane.

[0025] The power generation section 11 of this embodiment has a rectangular shape having a pair of sides extending along the second direction Y and a pair of sides extending along the third direction Z. In Fig. 2, an anode electrode is disposed on the upper surface of the electrolyte membrane, and a cathode electrode is disposed on the lower surface of the electrolyte membrane.

[0026] <Anode-side separator 30> As shown in FIGS. 2 to 4, the anode separator 30 is disposed opposite the anode electrode of the power generating section 11.

[0027] The anode side separator 30 has supply side manifolds 311, 312, 313 and discharge side manifolds 315, 316, 317 which constitute the supply side manifolds 111, 112, 113 and the discharge side manifolds 115, 116, 117, respectively.

[0028] As shown in Fig. 4, the anode separator 30 has a facing surface 30a, which faces the power generation section 11, provided with first groove channels 31 for supplying fuel gas to the power generation section 11. The first groove channels 31 are formed by a plurality of grooves 31a provided in the facing surface 30a. The first groove channels 31 are located between the supply manifold 312 and the discharge manifold 316 in the third direction Z. The first groove channels 31 extend in a substantially S-shape from the supply manifold 312 toward the discharge manifold 316. The portions of the plurality of first groove channels 31 that extend in the third direction Z are curved and wavy.

[0029] The first groove flow path 31 has a power generation region portion 32 facing the power generation portion 11, a supply side connection region portion 33 located at the end of the first groove flow path 31 on the supply side manifold 312 side, and a discharge side connection region portion 34 located at the end of the first groove flow path 31 on the discharge side manifold 316 side.

[0030] The power generation region 32 is located between the supply manifold 311 and the discharge manifold 315 in the second direction Y. The supply-side connection region 33 is located closer to the supply-side manifold 312 than the power generation region 11 in the third direction Z, and connects the power generation region 32 and the supply-side manifold 312.

[0031] The discharge-side connection region 34 is located closer to the discharge-side manifold 316 than the power generation region 11 in the third direction Z, and connects the power generation region 32 and the discharge-side manifold 316 together.

[0032] As shown in Figures 2 and 3, a plurality of protrusions 31b extending along the plurality of grooves 31a that constitute the first groove flow path 31 are formed on the opposite surface 30b of the anode side separator 30, which is the surface opposite to the opposing surface 30a.

[0033] The opposite surface 30b is provided with a cooling flow path 35 through which a cooling medium flows to cool the power generation section 11. The cooling flow path 35 is formed by a groove between adjacent ridges 31b on the opposite surface 30b side of the power generation region 32.

[0034] The anode separator 30 is formed by hot pressing a resin plate containing a conductive material. <Cathode-side separator 40> As shown in FIGS. 2 to 4, the cathode separator 40 is disposed opposite the cathode electrode of the power generation section 11.

[0035] The cathode-side separator 40 of this embodiment has the same shape as the anode-side separator 30. The cathode-side separator 40 is disposed in an inverted position relative to the anode-side separator 30, centered on an imaginary line L that passes through the center of the anode-side separator 30 in the second direction Y and extends along the third direction Z.

[0036] In the following description, the configuration of the cathode-side separator 40 will be designated by a reference number obtained by adding "10" to the reference number "**" of the anode-side separator 30, and redundant explanations may be omitted.

[0037] The cathode separator 40 has supply manifolds 411, 412, 413 and discharge manifolds 415, 416, 417 which constitute the supply manifolds 111, 112, 113 and the discharge manifolds 115, 116, 117, respectively.

[0038] As shown in Fig. 4, the cathode separator 40 has a facing surface 40a, which faces the power generation unit 11, that is provided with second groove channels 41 for supplying oxidizing gas to the power generation unit 11. The second groove channels 41 are formed by a plurality of grooves 41a provided in the facing surface 40a. The second groove channels 41 are located between the supply-side manifold 413 and the discharge-side manifold 417 in the third direction Z. The second groove channels 41 extend in a substantially S-shape from the supply-side manifold 413 toward the discharge-side manifold 417. The portions of the plurality of second groove channels 41 that extend in the third direction Z are curved and wavy.

[0039] The second groove flow path 41 has a power generation area portion 42 facing the power generation portion 11, a supply side connection area portion 43 located at the end of the second groove flow path 41 on the supply side manifold 413 side, and a discharge side connection area portion 44 located at the end of the second groove flow path 41 on the discharge side manifold 417 side.

[0040] The power generation region 42 is located between the supply manifold 411 and the discharge manifold 415 in the second direction Y. The supply-side connection region 43 is located closer to the supply-side manifold 413 than the power generation region 11 in the third direction Z, and connects the power generation region 42 and the supply-side manifold 413.

[0041] The discharge-side connection region 44 is located closer to the discharge-side manifold 417 than the power generation region 11 in the third direction Z, and connects the power generation region 42 and the discharge-side manifold 417.

[0042] As shown in Figures 2 and 3, on the opposite surface 40b of the cathode side separator 40, which is the surface opposite to the opposing surface 40a, multiple protrusions 41b are formed extending along the multiple grooves 41a that constitute the second groove flow path 41.

[0043] Additionally, the opposite surface 40b is provided with a cooling flow path 45 through which a cooling medium flows to cool the power generation section 11. The cooling flow path 45 is formed by a groove between adjacent ridges 41b on the opposite surface 40b side of the power generation region 42.

[0044] The cathode separator 40 is formed by hot pressing a resin plate containing a conductive material. <Gasket 50> 1 and 2, the gasket 50 is provided between the anode-side separator 30 of the unit cell 10A and the cathode-side separator 40 of the unit cell 10B, and seals the gap between the anode-side separator 30 and the cathode-side separator 40. The gasket 50 also surrounds the supply-side manifold 111, the discharge-side manifold 115, and the cooling channels 35 and 45.

[0045] The gasket 50 is fixed to the opposite surface 30b of the anode-side separator 30 by, for example, an adhesive. In this embodiment, the gasket 50 has a rectangular frame shape in a plan view, and has a pair of short sides 51 extending along the third direction Z and a pair of long sides 52 extending along the second direction Y.

[0046] <Frame member 20> 2, an opening 21 is provided in the center of the frame member 20, penetrating the frame member 20 in the first direction X. In this embodiment, the opening 21 has a rectangular shape having a pair of sides extending along the second direction Y and a pair of sides extending along the third direction Z.

[0047] The inner periphery of the opening 21 is joined to the periphery of the power generating section 11 from one side in the first direction X (the upper side in FIG. 2). The frame member 20 has supply side manifolds 211, 212, 213 and discharge side manifolds 215, 216, 217 which respectively constitute the supply side manifolds 111, 112, 113 and the discharge side manifolds 115, 116, 117.

[0048] The frame member 20 is provided with a plurality of supply-side through holes 25, 26 and a plurality of discharge-side through holes 27, 28 that penetrate the frame member 20 in the first direction X. The supply-side through holes 25, 26 and the discharge-side through holes 27, 28 are elongated holes that extend in the third direction Z.

[0049] As shown in FIG. 5, the fuel gas flowing inside the supply-side manifold 112 is supplied to the first groove flow path 31 through the supply-side manifold 312 and the supply-side through-hole 25. Although not shown in the drawings, the off-gas of the fuel gas that has flowed through the first groove flow passage 31 is discharged to the discharge-side manifold 116 through the discharge-side through-holes 27 and the discharge-side manifold 316.

[0050] The oxidizing gas flowing in the supply-side manifold 113 is supplied to the second groove flow path 41 through the supply-side manifold 413 and the supply-side through-hole 26 . The off-gas of the oxidizing gas that has flowed through the second groove flow passage 41 is discharged to the discharge manifold 117 through the discharge through-holes 28 and the discharge manifold 417 .

[0051] The frame member 20 is made of a synthetic resin material. <Details of the configuration of the anode-side separator 30 and the cathode-side separator 40> As shown in FIG. 6, the anode separator 30 has a first protrusion 60 and a first rib 65 .

[0052] The first protrusion 60 and the first rib 65 protrude toward the opposite side from the power generation section 11. In this embodiment, the first protrusion 60 and the first rib 65 are arranged point-symmetrically about the center C (see FIG. 2) in the planar direction of the anode-side separator 30. Therefore, hereinafter, only the first protrusion 60 and the first rib 65 arranged to the right of the power generation section 11 in FIG. 7 will be described.

[0053] The first protrusion 60 is located between the cooling flow path 35 and the long side 52 of the gasket 50 in the third direction Z. In addition, the first protrusion 60 is located closer to the discharge-side manifold 315 than the discharge-side connection region 34 in the second direction Y.

[0054] The first protrusion 60 has a rectangular shape in a plan view, and has a pair of long sides extending along the second direction Y and a pair of short sides extending along the third direction Z. The first protrusion 60 has a portion that abuts against a portion of the plurality of protrusions 41b on the cathode separator 40 of the other unit cell 10B, which is indicated by the two-dot chain line in FIG.

[0055] Recesses 61 are provided on the surface of the first protrusion 60. In this embodiment, the recesses 61 are elongated holes, and eight recesses 61 are provided on the surface of the first protrusion 60. The recesses 61 extend so as to intersect with a plurality of protrusions 41b on the cathode-side separator 40 of the unit cell 10B, which are indicated by the two-dot chain line in FIG. 6. In this embodiment, the recesses 61 are inclined so that the closer they are to the gasket 50 in the third direction Z, the closer they are to the discharge-side manifold 315 in the second direction Y.

[0056] As shown in FIGS. 4 and 7, the first protrusion 60 has a rear surface provided with a flat surface 62 that comes into contact with the frame member 20. As shown in FIG. 6, a plurality of first ribs 65 are provided in a portion between the supply-side manifold 311 and the cooling channel 35 in the second direction Y, and in a portion between the discharge-side manifold 315 and the cooling channel 35 in the second direction Y. In this embodiment, seven first ribs 65 are provided in a portion between the supply-side manifold 311 and the cooling channel 35 in the second direction Y, and in a portion between the discharge-side manifold 315 and the cooling channel 35 in the second direction Y. The plurality of first ribs 65 are arranged at intervals from one another in the third direction Z. The first ribs 65 are inclined so that the closer they are to the supply-side manifold 313 in the third direction Z, the further they are from the discharge-side manifold 315 in the second direction Y (see FIG. 3). Grooves 66 are provided on the back surface of the first rib 65 (see FIG. 4).

[0057] As described above, the cathode-side separator 40 of this embodiment has the same shape as the anode-side separator 30. Therefore, the second protrusions 70 and second ribs 75 correspond to the inverted first protrusions 60 and first ribs 65 of the anode-side separator 30.

[0058] The second protrusions 70 of the cathode-side separator 40, indicated by the two-dot chain line in Fig. 6, are in contact with the first protrusions 60 of the anode-side separator 30, indicated by the solid line in Fig. 6, and the protrusions 31b of the discharge-side connection region 34. The recesses 71 of the second protrusions 70 of the cathode-side separator 40, indicated by the two-dot chain line in Fig. 6, extend so as to intersect with the recesses 61 of the first protrusions 60 of the anode-side separator 30, indicated by the solid line in Fig. 6. Furthermore, the recesses 71 of the cathode-side separator 40, indicated by the two-dot chain line in Fig. 6, extend so as to intersect with the protrusions 31b of the discharge-side connection region 34 of the anode-side separator 30, indicated by the solid line in Fig. 6.

[0059] The second rib 75 of the cathode separator 40 shown by the two-dot chain line in FIG. 6 and the first rib 65 of the anode separator 30 shown by the solid line in FIG. 6 are in contact with each other and extend so as to intersect with each other.

[0060] In this embodiment, the anode-side separator 30 and the cathode-side separator 40 correspond to the first separator and the second separator, respectively, according to the present invention. Furthermore, the fuel gas and the oxidizing gas in this embodiment correspond to the first reactant gas and the second reactant gas, respectively, according to the present invention. Furthermore, the portion of the anode-side separator 30 to which the gasket 50 is adhered corresponds to the gasket attachment portion, respectively, according to the present invention.

[0061] <Operation of this embodiment> 7, the first protrusion 60 of the anode-side separator 30 and the second protrusion 70 of the cathode-side separator 40 come into contact with each other, thereby preventing the cooling medium from flowing outside the cooling channels 35, 45, i.e., preventing the cooling medium from flowing to the side. This allows the power generation section 11 to be effectively cooled by the cooling medium.

[0062] Furthermore, the flat surfaces 62, 72 provided on the rear surfaces of the first protrusion 60 and the second protrusion 70 come into contact with the frame member 20. This prevents the reactant gas from flowing outside the groove flow paths 31, 41 between the frame member 20 and the separators 30, 40, i.e., prevents the reactant gas from flowing to the side.

[0063] <Effects of this embodiment> (1) The anode-side separator 30 and the cathode-side separator 40 of the unit cell 10B are provided with a first protrusion 60 and a second protrusion 70, respectively, which are located between the cooling channels 35, 45 and the gasket 50. The back surfaces of the first protrusion 60 and the second protrusion 70 have flat surfaces 62, 72 that abut against the frame member 20. The first protrusion 60 and the second protrusion 70 protrude so as to abut against each other, thereby preventing the coolant from flowing outside the cooling channels 35, 45.

[0064] According to this configuration, the above-mentioned effects are achieved, and therefore it is possible to suppress sideways flow of the cooling medium and sideways flow of the reactant gas. (2) The back surfaces of both the first protrusion 60 and the second protrusion 70 have flat surfaces 62 , 72 that come into contact with the frame member 20 .

[0065] This configuration prevents fuel gas from flowing outside the first groove flow passages 31 between the frame member 20 and the anode-side separator 30. Also, it prevents oxidizing gas from flowing outside the second groove flow passages 41 between the frame member 20 and the cathode-side separator 40. Therefore, it is possible to prevent the fuel gas and oxidizing gas from flowing by the side.

[0066] (3) The anode separator 30 and the cathode separator 40 are made of resin. With this configuration, the anode-side separator 30 and the cathode-side separator 40 in which the flat portions 62, 72 are provided on the rear surfaces of the first protrusions 60 and the second protrusions 70 can be easily formed.

[0067] (4) The first protrusion 60 and the second protrusion 70 have recesses 61, 71 on the surfaces thereof. In the resin separators 30, 40, the first protrusions 60 and the second protrusions 70 are provided on their rear surfaces with flat surfaces 62, 72 that come into contact with the frame member 20, which increases the thickness of the separators 30, 40 in some places. This may result in molding defects in the first protrusions 60 and the second protrusions 70. As a result, the first protrusions 60 and the second protrusions 70 may not make proper contact with each other, or the flat surfaces 62, 72 may not make proper contact with the frame member 20.

[0068] In this regard, according to the above configuration, the first protrusion 60 and the second protrusion 70 that have flat portions 62, 72 on the back surface have recesses 61, 71 on the front surface, thereby preventing molding defects caused by localized increases in thickness.

[0069] (5) The recesses 61 and 71 of the unit cell 10A extend so as to intersect with the ridges 41b and 31b of the unit cell 10B. This configuration prevents the ridges 41b, 31b from entering the recesses 61, 71 of the first and second ridges 60, 70. Therefore, by ensuring favorable contact between the ridges 41b, 31b and the first and second ridges 60, 70, it is possible to increase the surface pressure between the separators 30, 40 and the frame member 20. This makes it possible to prevent the reaction gas from flowing sideways from the grooves 31, 41 through the spaces between the separators 30, 40 and the frame member 20.

[0070] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0071] In the above embodiment, the recesses 61 of the first protrusions 60 and the recesses 71 of the second protrusions 70 extend so as to intersect with the ridges 41b of the supply-side connection region 43 and the ridges 31b of the discharge-side connection region 34, respectively. However, this is not limited to this. The recesses 61 of the first protrusions 60 and the recesses 71 of the second protrusions 70 may also extend along the ridges 41b of the supply-side connection region 43 and the ridges 31b of the discharge-side connection region 34, respectively.

[0072] In the above embodiment, the first protrusion 60 and the second protrusion 70 have portions that abut against the ridges 41b of the supply-side connection area 43 and the ridges 31b of the discharge-side connection area 34, respectively, but this is not limiting. The first protrusion 60 and the second protrusion 70 do not have to extend to positions where they abut against the ridges 41b of the supply-side connection area 43 and the ridges 31b of the discharge-side connection area 34, respectively.

[0073] In the above embodiment, the recesses 61, 71 are formed as elongated holes, but the shape of the recesses 61, 71 may be, for example, circular in plan view. The recesses 61, 71 of the first protrusion 60 and the second protrusion 70 may be omitted if molding defects do not occur in the first protrusion 60 and the second protrusion 70.

[0074] In the above embodiment, the first protrusions 60 and the second protrusions 70 are formed on the anode-side separator 30 and the cathode-side separator 40, respectively, by hot pressing a resin plate containing a conductive material, but this is not limiting. For example, the first protrusions 60 and the second protrusions 70 may be joined as separate members to the metal anode-side separator 30 and the metal cathode-side separator 40, on which the first groove flow paths 31 and the second groove flow paths 41 are formed by pressing.

[0075] In the above embodiment, flat surfaces 62, 72 that come into contact with the frame member 20 are provided on the back surfaces of both the first protrusion 60 and the second protrusion 70, but a flat surface may also be provided on the back surface of at least one of the first protrusion 60 and the second protrusion 70.

[0076] In the above embodiment, the first protrusions 60 are provided only between the cooling channels 35 and the long sides 52 of the gasket 50 in the third direction Z, but this is not limiting. A first protrusion may also be provided between the cooling channels 35 and the short sides 51 of the gasket 50 in the second direction Y. For example, as shown in FIG. 8 , the anode separator 30 is provided with two first protrusions 160, 260 on both sides of the anode separator 30 on the outer side of the supply manifold 311 in the third direction Z. The first protrusion 160 has a first portion 163 and a second portion 164. The first portion 163 is located between the cooling channels 35 and the long sides 52 of the gasket 50 in the third direction Z and extends closer to the supply manifold 311 in the second direction Y than the cooling channels 35. The second portion 164 protrudes inward in the third direction Z from the end of the first portion 163 on the supply-side manifold 311 side in the second direction Y, and is located between the cooling flow path 35 and the short side 51 of the gasket 50 in the second direction Y. The first protrusion 260 extends in the third direction Z and extends outward in the third direction Z beyond the cooling flow path 35. The outer end of the first protrusion 260 in the third direction Z is adjacent to the long side 52 of the gasket 50. The second portion 164 of the first protrusion 160 and the first protrusion 260 are located closer to the cooling flow path 35 than the supply-side manifold 311. Similarly, two second protrusions 170, 270 are provided on the cathode-side separator 40 on both sides outside the supply-side manifold 411 in the third direction Z. The second protrusion 170 has a first portion 173 and a second portion 174. The first portion 173 is located between the cooling flow passage 45 and the long side 52 of the gasket 50 in the third direction Z and extends closer to the supply side manifold 411 than the cooling flow passage 45 in the second direction Y. The second portion 174 protrudes inward in the third direction Z from the end of the first portion 173 on the supply side manifold 411 side in the second direction Y and is located between the cooling flow passage 45 and the short side 51 of the gasket 50 in the second direction Y. The second protrusion 270 extends in the third direction Z and extends further outward than the cooling flow passage 45 in the third direction Z. An outer end of the second protrusion 270 in the third direction Z is adjacent to the long side 52 of the gasket 50.The second portion 174 of the second protrusion 170 and the second protrusion 270 are located closer to the cooling flow passage 45 than the supply side manifold 411. [Explanation of symbols]

[0077] 10...Single cell 11...Power generation section 20...Frame member 21...Opening 25,26…Supply side through hole 27,28…Discharge side through hole 30...Anode side separator (first separator) 30a...Opposing surface 30b...opposite side 31...First groove channel 31a...Groove 31b...projection 32...Power generation area 33...Supply side connection area 34...Discharge side connection area 35...Cooling channel 40...Cathode side separator (second separator) 40a...opposing surface 40b...opposite side 41...Second groove channel 41a...Groove 41b...projection 42...Power generation area 43...Supply side connection area 44...Discharge side connection area 45...Cooling channel 50...Gasket 51...short side 52...long side 60...First protrusion 61...recess 62…Plane part 65...First Rib 66…Groove 70...Second protrusion 71...recess 72...Plane part 75...Second rib 111, 211, 311, 411...Supply side manifold 112, 212, 312, 412...Supply side manifold 113, 213, 313, 413...Supply side manifold 115, 215, 315, 415...Discharge side manifold 116, 216, 316, 416...Discharge side manifold 117, 217, 317, 417...Discharge side manifold 160...First protrusion 163…Part 1 164…Second part 170...Second protrusion 173…Part 1 174…Second part 260...First protrusion 270...Second protrusion

Claims

1. A fuel cell stack formed by stacking a plurality of unit cells, each unit cell including a power generation section, a frame member provided around the power generation section to hold the power generation section, and a first separator and a second separator sandwiching the power generation section and the frame member, a first groove flow path and a second groove flow path through which a first reactant gas and a second reactant gas supplied to the power generation section flow, respectively, are provided on opposing surfaces of the first separator and the second separator that face the power generation section; a cooling flow path through which a cooling medium for cooling the power generation section flows is provided on an opposite surface of each of the first separator and the second separator, the opposite surface being opposite to the opposing surface; a gasket is provided between the first separator and the second separator of another unit cell stacked on the first separator, the gasket surrounding the cooling flow path and sealing the gap between the first separator and the second separator; the first separator and the second separator of the other unit cell are provided with a first protrusion and a second protrusion that are positioned between the cooling flow path and the gasket and that protrude so as to abut against each other to prevent the cooling medium from flowing outside the cooling flow path, a back surface of at least one of the first protrusion and the second protrusion has a flat surface that abuts against the frame member; Fuel cell stack.

2. a back surface of each of the first protrusion and the second protrusion has a flat surface that abuts against the frame member; The fuel cell stack of claim 1 .

3. the first separator and the second separator are made of resin; 3. The fuel cell stack according to claim 1 or 2.

4. the first protrusion and the second protrusion have recesses on their surfaces, The fuel cell stack according to claim 3 .

5. The first groove flow path and the second groove flow path are a power generation region facing the power generation section; a supply-side connection region connecting the power generation region with a supply-side manifold that supplies the first reactant gas or the second reactant gas to the first groove flow path or the second groove flow path; a discharge-side connection region that connects the power generation region to a discharge-side manifold that discharges the first reactant gas or the second reactant gas from the first groove flow path or the second groove flow path, a plurality of protrusions extending along a plurality of grooves that form the first groove flow path and the second groove flow path are formed on the opposite surface of each of the first separator and the second separator, the first protrusion or the second protrusion has a portion that abuts against a portion of the plurality of protrusions in the second separator or the first separator of another unit cell that is stacked on the first separator or the second separator having the first protrusion or the second protrusion, the portion corresponding to the supply-side connection region or the discharge-side connection region; The recess extends so as to intersect with the ridge. The fuel cell stack according to claim 4 .

6. A separator of a fuel cell is disposed opposite a power generation section of the fuel cell and a frame member that is provided around the power generation section and holds the power generation section, a groove flow path through which a reactant gas supplied to the power generation unit flows is provided on an opposing surface that faces the power generation unit, a cooling flow path through which a cooling medium for cooling the power generation unit flows is provided on an opposite surface to the opposing surface, an attachment portion is provided on the opposite surface to which a gasket is attached, the gasket surrounding the cooling flow path and providing a seal between the separator and another separator stacked on the separator; a protrusion is provided on the opposite surface, the protrusion being located between the cooling flow path and the gasket and protruding to come into contact with the other separator, thereby preventing the cooling medium from flowing outside the cooling flow path; The back surface of the protrusion has a flat surface that abuts against the frame member. Fuel cell separator.

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