Fuel cell stack and separator for fuel cell

Abstract

The invention relates to a fuel cell stack and a separator of a fuel cell. The fuel cell stack is provided with a plurality of stacked unit cells. Each single cell includes a power generation unit, a frame member, and a first separator and a second separator. A gasket is provided between the first separator of the first cell and the second separator of the second cell. The first separator of the first cell has a first protrusion, and the second separator of the second cell has a second protrusion. The first protruding portion and the second protruding portion are configured so as to protrude so as to abut against each other, thereby suppressing the flow of the cooling medium to the outside of the cooling flow path. The back surface of at least one of the first protrusion and the second protrusion is provided with a flat surface portion which abuts against the frame member opposite to the back surface.

Description

Technical Field

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

[0002] Japanese Patent Application Publication No. 2023-123116 describes a fuel cell stack. The fuel cell stack described in the publication includes a plurality of stacked single cells. Each single cell includes a power generation unit, a frame member disposed around the power generation unit to hold the power generation unit, and a first separator and a second separator that clamp the power generation unit and the frame member. The first separator and the second separator each have an opposing surface that faces the power generation unit and an opposite surface located on the opposite side of the opposing surface. A slot flow path for the flow of a first reaction gas is provided on the opposing surface of the first separator. A slot flow path for the flow of a second reaction gas is provided on the opposing surface of the second separator. A slot flow path for the flow of a cooling medium is provided on each opposing surface of the first separator and the second separator.

[0003] Here, any one of the stacked cells is referred to as a first cell, and the cell having the second separator stacked on the first separator of the first cell is referred to as a second cell. In this case, the first separator of the first cell is provided with a first protrusion that protrudes toward the second separator of the second cell. The second separator of the second cell is provided with a second protrusion that protrudes toward the first protrusion of the first separator of the first cell and abuts against the first protrusion.

[0004] The first and second protrusions are arranged along the extending direction of the slot flow path at a position outward from the outermost portion of the slot flow path in a direction orthogonal to both the extending direction and the stacking direction of the slot flow path (hereinafter referred to as the width direction).

[0005] The first separator and the second separator are formed by press-forming a metal plate. Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Because the first and second separators are formed by stamping metal sheets, recesses are formed on the backside of the first protrusion in the first separator and the backside of the second protrusion in the second separator. This can cause so-called bypass flow of reactant gas, where reactant gas flowing in the slot flow path flows into these recesses through the gaps between the frame member and the separator. This results in reduced reactant gas supply to the power generation section, leading to lower power generation efficiency. Therefore, it is necessary to simultaneously suppress bypass flow of the coolant and reactant gas.

[0008] Solutions to Problems

[0009] The fuel cell stack of one embodiment of the present disclosure comprises a plurality of stacked single cells, wherein each single cell comprises: a power generation unit; a frame member arranged around the power generation unit to hold the power generation unit; and a first separator and a second separator for clamping the power generation unit and the frame member, the first separator and the second separator respectively having an opposing surface opposite to the power generation unit and an opposite surface located on the opposite side of the opposing surface, a first groove flow path being provided on the opposing surface of the first separator, the first groove flow path being configured to supply a first reaction gas supplied to the power generation unit with a flow, a second groove flow path being provided on the opposing surface of the second separator, the second groove flow path being configured to supply a second reaction gas supplied to the power generation unit with a flow, and cooling flow paths being provided on the opposite surface of the first separator and the opposite surface of the second separator, respectively, the cooling flow paths being configured to supply a cooling medium flow for cooling the power generation unit with a flow 18. The cooling unit of claim 17, wherein the cooling unit comprises a first portion extending along the length of the cooling unit and a second portion extending along the length of the cooling unit. The cooling unit comprises a first portion extending along the length of the cooling unit and a second portion extending along the length of the cooling unit. The cooling unit comprises a first portion extending along the length of the cooling unit and a second portion extending along the length of the cooling unit.

[0010] A fuel cell separator according to one aspect of the present disclosure is configured to be arranged to face a power generation section of a fuel cell and a frame member provided around the power generation section to hold the power generation section. The fuel cell separator includes a facing surface configured to face the power generation section and an opposing surface located opposite the facing surface. A groove flow path is provided on the facing surface, the groove flow path configured to allow a reactant gas supplied to the power generation section to flow. A cooling flow path is provided on the opposing surface, the cooling flow path configured to allow a coolant to flow for cooling the power generation section to flow. A mounting portion is provided on the opposing surface to which a gasket is mounted. The gasket surrounds the cooling flow path and seals the separator from other separators stacked thereon. A protrusion is provided on the opposing surface, the protrusion being configured to be located between the cooling flow path and the gasket. The protrusion is configured to prevent the coolant from flowing outside the cooling flow path by protruding so as to abut against the other separators. The rear surface of the protrusion has a flat portion configured to abut against the frame member. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is an exploded perspective view of a fuel cell stack according to one embodiment.

[0012] Figure 2 yes Figure 1 Exploded perspective view of a single battery.

[0013] Figure 3 It is a plan view of the anode-side separator with the gasket bonded thereto.

[0014] Figure 4 yes Figure 3 Bottom view of the anode side separator.

[0015] Figure 5 It is along Figure 2 Cross-sectional view of line 5-5.

[0016] Figure 6 It will Figure 3 A main part is enlarged to show a top view.

[0017] Figure 7 It is along Figure 6 Cross-sectional view of line 7-7.

[0018] Figure 8 It is a plan view showing a modified example of the anode-side separator. DETAILED DESCRIPTION

[0019] Below, refer to Figures 1 to 7 An embodiment of a fuel cell stack and a fuel cell separator will be described.

[0020] In addition, in each drawing, for convenience of explanation, part of the structure is exaggerated or simplified, and therefore the dimensional ratios of each structure may differ from the actual ones.

[0021] like Figure 1 As shown, the fuel cell stack is formed by stacking a plurality of single cells 10. Figure 1 , two cells 10A and 10B are shown among the plurality of cells 10 constituting the fuel cell stack.

[0022] <Single cell 10>

[0023] like Figure 2 As shown, the cell 10 includes a membrane electrode assembly (hereinafter referred to as a power generation unit 11), a frame member 20 provided around the power generation unit 11 to hold the power generation unit 11, and an anode-side separator 30 and a cathode-side separator 40 that sandwich the power generation unit 11 and the frame member 20. The cell 10 of this embodiment is generally in the shape of a rectangular plate.

[0024] The following description will be made with the stacking direction of the plurality of cells 10 being the first direction X. Furthermore, the short side direction and long side direction of the cells 10 will be made the second direction Y and the third direction Z. The first direction X, the second direction Y, and the third direction Z constitute an orthogonal coordinate system.

[0025] The cell 10A corresponds to any one of the plurality of cells 10, and the cell 10B corresponds to the cell 10 having the cathode separator 40 stacked on the anode separator 30 of the cell 10A, among the plurality of cells 10. Hereinafter, the cell 10A will be referred to as the first cell 10A, and the cell 10B will be referred to as the second cell 10B.

[0026] like Figure 1 and Figure 2 As shown, the cell 10 has supply-side manifolds 111, 112, and 113 for supplying cooling water, fuel gas, and oxidizing gas into the cell 10. Furthermore, the cell 10 has discharge-side manifolds 115, 116, and 117 for discharging cooling water, fuel gas, and oxidizing gas from the cell 10 to the outside.

[0027] The supply-side manifolds 111 , 112 , and 113 and the discharge-side manifolds 115 , 116 , and 117 penetrate the single cells 10 in the first direction X.

[0028] The supply-side manifold 111 is provided on one side of the battery cell 10 in the second direction Y ( Figure 1 and Figure 2 on the lower left side of the ).

[0029] The discharge side manifold 115 is provided on the other side of the battery cell 10 in the second direction Y ( Figure 1 and Figure 2 on the upper right side of the ).

[0030] The supply-side manifold 113 and the discharge-side manifold 116 are provided on one side of the single cell 10 in the third direction Z ( Figure 1 and Figure 2 The supply-side manifold 113 and the discharge-side manifold 116 are sequentially arranged in the second direction Y at intervals from each other.

[0031] The supply-side manifold 112 and the discharge-side manifold 117 are provided on the other side of the unit cell 10 in the third direction Z ( Figure 1 and Figure 2 The supply-side manifold 112 and the discharge-side manifold 117 are arranged in sequence in the second direction Y at intervals from each other.

[0032] <Power Generation Unit 11>

[0033] like Figure 2 As shown, the power generation section 11 includes a solid polymer electrolyte membrane (hereinafter referred to as an electrolyte membrane), and an anode electrode and a cathode electrode provided on both surfaces of the electrolyte membrane.

[0034] The power generation unit 11 of this embodiment is formed into 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. Figure 2 In the embodiment, an anode electrode is arranged on the upper surface of the electrolyte membrane, and a cathode electrode is arranged on the lower surface of the electrolyte membrane.

[0035] <Anode-side separator 30>

[0036] like Figures 2 to 4 As shown, the anode-side separator 30 is arranged to face the anode electrode of the power generation section 11 .

[0037] The anode-side separator 30 includes supply-side manifolds 311 , 312 , 313 and discharge-side manifolds 315 , 316 , 317 , which respectively constitute the supply-side manifolds 111 , 112 , 113 and the discharge-side manifolds 115 , 116 , 117 .

[0038] like Figure 4 As shown, the anode-side separator 30 has an opposing surface 30a that faces the power generation section 11. A first slotted flow path 31 for supplying fuel gas to the power generation section 11 is provided on the opposing surface 30a. The first slotted flow path 31 is formed by a plurality of slots 31a provided on the opposing surface 30a. The first slotted flow path 31 is located between the supply-side manifold 312 and the discharge-side manifold 316 in the third direction Z. The first slotted flow path 31 extends in a generally S-shaped manner from the supply-side manifold 312 toward the discharge-side manifold 316. Furthermore, the portions of the plurality of first slotted flow paths 31 that extend along the third direction Z are curved and wavy.

[0039] The first slot flow path 31 includes a power generation region 32 facing the power generation section 11 , a supply side connection region 33 located at an end of the first slot flow path 31 on the supply side manifold 312 side, and a discharge side connection region 34 located at an end of the first slot flow path 31 on the discharge side manifold 316 side.

[0040] The power generation region 32 is located between the supply-side manifold 311 and the discharge-side manifold 315 in the second direction Y.

[0041] The supply-side connecting region 33 is located closer to the supply-side manifold 312 than the power generation section 11 in the third direction Z, and connects the power generation region 32 and the supply-side manifold 312 .

[0042] The discharge-side connecting region 34 is located closer to the discharge-side manifold 316 than the power generation section 11 in the third direction Z, and connects the power generation region 32 and the discharge-side manifold 316 .

[0043] like Figure 2 and Figure 3 As shown, the anode-side separator 30 has an opposite surface 30b located opposite to the facing surface 30a. A plurality of protrusions 31b extending along the plurality of grooves 31a constituting the first groove flow path 31 are formed on the opposite surface 30b.

[0044] The opposite surface 30b is provided with a cooling channel 35 through which a cooling medium for cooling the power generation section 11 flows. The cooling channel 35 is formed on the opposite surface 30b side of the power generation region 32 by grooves between adjacent protrusions 31b.

[0045] The anode-side separator 30 is formed by hot-pressing a plate made of a resin containing a conductive material.

[0046] <Cathode-side separator 40>

[0047] like Figures 2 to 4 As shown, the cathode-side separator 40 is arranged to face the cathode electrode of the power generation section 11 .

[0048] The cathode separator 40 of this embodiment has the same shape as the anode separator 30. The cathode separator 40 is arranged in a posture in which the anode separator 30 is reversed with an imaginary straight line L passing through the center of the anode separator 30 in the second direction Y and extending in the third direction Z as the center.

[0049] Hereinafter, the structure of the cathode-side separator 40 is denoted by adding “10” to the symbol “**” of the anode-side separator 30 , and overlapping descriptions may be omitted.

[0050] The cathode-side separator 40 includes supply-side manifolds 411 , 412 , 413 and discharge-side manifolds 415 , 416 , 417 , which respectively constitute the supply-side manifolds 111 , 112 , 113 and the discharge-side manifolds 115 , 116 , 117 .

[0051] like Figure 4 As shown, the cathode-side separator 40 has an opposing surface 40a that faces the power generation section 11. A second slot flow path 41 for supplying oxidizing gas to the power generation section 11 is provided on the opposing surface 40a. The second slot flow path 41 is formed by a plurality of slots 41a provided on the opposing surface 40a. The second slot flow path 41 is located between the supply-side manifold 413 and the discharge-side manifold 417 in the third direction Z. The second slot flow path 41 extends in a generally S-shaped manner from the supply-side manifold 413 toward the discharge-side manifold 417. Furthermore, the portions of the plurality of second slot flow paths 41 that extend along the third direction Z are curved and wavy.

[0052] The second slot flow path 41 has a power generation region 42 opposite to the power generation section 11 , a supply side connection region 43 located at the end of the second slot flow path 41 on the supply side manifold 413 side, and a discharge side connection region 44 located at the end of the second slot flow path 41 on the discharge side manifold 417 side.

[0053] The power generation region 42 is located between the supply-side manifold 411 and the discharge-side manifold 415 in the second direction Y.

[0054] The supply-side connecting region 43 is located closer to the supply-side manifold 413 than the power generation section 11 in the third direction Z, and connects the power generation region 42 and the supply-side manifold 413 .

[0055] The discharge-side connecting region 44 is located closer to the discharge-side manifold 417 than the power generation section 11 in the third direction Z, and connects the power generation region 42 and the discharge-side manifold 417 .

[0056] like Figure 2 and Figure 3 As shown, the cathode-side separator 40 has an opposite surface 40b located opposite to the facing surface 40a. A plurality of protrusions 41b extending along the plurality of grooves 41a constituting the second groove flow paths 41 are formed on the opposite surface 40b.

[0057] Furthermore, a cooling channel 45 is provided on the opposite surface 40b for allowing a coolant to flow to cool the power generation section 11. The cooling channel 45 is formed on the opposite surface 40b side of the power generation region 42 by grooves between adjacent ridges 41b.

[0058] The cathode-side separator 40 is formed by hot-pressing a plate made of a resin containing a conductive material.

[0059] Washer 50

[0060] like Figure 1 and Figure 2 As shown, the gasket 50 is provided between the anode separator 30 of the first cell 10A and the cathode separator 40 of the second cell 10B, sealing the gap between the anode separator 30 and the cathode separator 40. Furthermore, the gasket 50 surrounds the supply manifold 111, the discharge manifold 115, and the cooling channels 35 and 45.

[0061] The gasket 50 is fixed to the opposite surface 30 b of the anode-side separator 30 by, for example, an adhesive.

[0062] In the present 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.

[0063] <Frame member 20>

[0064] like Figure 2 As shown, an opening 21 is provided in the center of the frame member 20 penetrating the frame member 20 in the first direction X. The opening 21 of this embodiment is formed in a rectangular shape having a pair of sides extending in the second direction Y and a pair of sides extending in the third direction Z.

[0065] The peripheral edge of the power generation unit 11 is from one side in the first direction X ( Figure 2 The upper side of the opening 21 is joined to the inner peripheral edge of the opening 21.

[0066] The frame member 20 includes 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 .

[0067] The frame member 20 is provided with a plurality of supply-side through-holes 25 and 26 and a plurality of discharge-side through-holes 27 and 28 that penetrate the frame member 20 in the first direction X. The supply-side through-holes 25 and 26 and the discharge-side through-holes 27 and 28 are elongated holes extending in the third direction Z.

[0068] like Figure 5 As shown, the fuel gas flowing in the supply-side manifold 112 is supplied to the first tank flow path 31 through the supply-side manifold 312 and the supply-side through-holes 25 .

[0069] Although not shown in the figure, the off-gas of the fuel gas flowing in the first tank flow path 31 is discharged to the discharge-side manifold 116 through the discharge-side through-hole 27 and the discharge-side manifold 316 .

[0070] The oxidizing gas flowing in the supply-side manifold 113 is supplied to the second tank flow path 41 through the supply-side manifold 413 and the supply-side through-holes 26 .

[0071] The exhaust gas of the oxidizing gas flowing in the second tank flow path 41 passes through the discharge-side through-hole 28 and the discharge-side manifold 417 and is discharged to the discharge-side manifold 117 .

[0072] The frame member 20 is formed of a synthetic resin material.

[0073] <Details of the Structure of the Anode-Side Separator 30 and the Cathode-Side Separator 40>

[0074] like Figure 6 As shown, the anode-side separator 30 has a first protrusion 60 and a first rib 65 .

[0075] The first protrusion 60 and the first rib 65 protrude toward the side opposite to the power generation section 11. In this embodiment, the first protrusion 60 and the first rib 65 are arranged with the center C in the plane direction of the anode side separator 30 (see Figure 2 ) is the point symmetry. Therefore, in the following, only Figure 6 The first protrusion 60 and the first rib 65 arranged on the right side of the power generation section 11 will be described.

[0076] 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. The first protrusion 60 is located closer to the discharge-side manifold 315 than the discharge-side connecting region 34 in the second direction Y.

[0077] 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 short side extending along the third direction Z.

[0078] like Figure 6 As shown, the first protrusion 60 of the first cell 10A has Figure 6 The portion of the plurality of protrusions 41 b of the cathode-side separator 40 of the second unit cell 10B indicated by the two-dot chain line abuts against the portion corresponding to the supply-side connecting region 43 .

[0079] The first protrusion 60 has recesses 61 formed on its surface. In this embodiment, the recesses 61 are elongated holes, and eight of them are formed on the surface of the first protrusion 60. Figure 6 In the present embodiment, the recess 61 is inclined so as to approach the discharge manifold 315 in the second direction Y as it approaches the gasket 50 in the third direction Z.

[0080] like Figure 4 and Figure 7 As shown, a flat surface portion 62 is provided on the back surface of the first protrusion 60 so as to abut against the frame member 20 facing the back surface.

[0081] like Figure 6As shown, a plurality of first ribs 65 are provided in the portion between the supply-side manifold 311 and the cooling flow path 35 in the second direction Y and in the portion between the discharge-side manifold 315 and the cooling flow path 35 in the second direction Y. In the present embodiment, seven first ribs 65 are provided in the portion between the supply-side manifold 311 and the cooling flow path 35 in the second direction Y and in the portion between the discharge-side manifold 315 and the cooling flow path 35 in the second direction Y. The plurality of first ribs 65 are arranged at intervals from each other in the third direction Z. The first ribs 65 are inclined in such a manner that the closer they are to the supply-side manifold 313 in the third direction Z, the farther they are from the discharge-side manifold 315 in the second direction Y (see Figure 3 A groove 66 is provided on the back surface of the first rib 65 (see Figure 4 ).

[0082] As described above, the cathode separator 40 of this embodiment has the same shape as the anode separator 30 . Therefore, the portion obtained by inverting the first protrusion 60 and the first rib 65 of the anode separator 30 corresponds to the second protrusion 70 and the second rib 75 .

[0083] Figure 6 The second protrusions 70 of the cathode-side separator 40 of the second cell 10B indicated by the two-dot chain line are respectively aligned with Figure 6 The first protrusion 60 of the anode-side separator 30 of the first cell 10A indicated by the solid line is in contact with the protrusion 31 b of the discharge-side connecting region 34 . Figure 6 The concave portion 71 of the second protrusion 70 of the cathode-side separator 40 of the second cell 10B shown by the two-dot chain line is aligned with Figure 6 The first protrusion 60 of the anode-side separator 30 of the first cell 10A shown by the solid line extends so as to intersect the recess 61. Figure 6 The concave portion 71 of the cathode-side separator 40 of the second cell 10B shown by the two-dot chain line is aligned with Figure 6 The protrusions 31 b of the discharge-side connecting region 34 of the anode-side separator 30 of the first unit cell 10A, indicated by the solid line, extend so as to intersect with each other.

[0084] Figure 6 The second rib 75 of the cathode-side separator 40 of the second cell 10B shown by the two-dot chain line is aligned with Figure 6 The first ribs 65 of the anode-side separator 30 of the first unit cell 10A indicated by the solid line extend so as to be in contact with each other and to intersect with each other.

[0085] In this embodiment, the anode-side separator 30 and the cathode-side separator 40 correspond to the first and second separators of the present disclosure, respectively. Furthermore, the fuel gas and oxidizing gas in this embodiment correspond to the first and second reactant gases of the present disclosure, respectively. Furthermore, the portion of the anode-side separator 30 to which the gasket 50 is bonded corresponds to the gasket mounting portion of the present disclosure.

[0086] <Function of this embodiment>

[0087] like Figure 7 As shown, the first protrusion 60 of the anode-side separator 30 abuts the second protrusion 70 of the cathode-side separator 40, thereby preventing the coolant from flowing outside the cooling flow paths 35 and 45, i.e., bypassing the cooling medium. Therefore, the power generation section 11 can be effectively cooled by the coolant.

[0088] Furthermore, the flat surfaces 62 and 72 provided on the back surfaces of the first and second protrusions 60 and 70 abut against the frame member 20. This prevents the reaction gas from bypassing the frame member 20 and the separators 30 and 40 and flowing outside the slot channels 31 and 41.

[0089] <Effects of this embodiment>

[0090] (1) The anode-side separator 30 of the first cell 10A is provided with a first protrusion 60 located between the cooling flow path 35 and the gasket 50. The cathode-side separator 40 of the second cell 10B is provided with a second protrusion 70 located between the cooling flow path 45 and the gasket 50. The back surface of the first protrusion 60 has a flat surface portion 62 that abuts the frame member 20 facing the back surface. The back surface of the second protrusion 70 has a flat surface portion 72 that abuts the frame member 20 facing the back surface. The first protrusion 60 and the second protrusion 70 protrude so as to abut each other, thereby preventing the coolant from flowing outside the cooling flow paths 35 and 45.

[0091] According to such a configuration, since the above-mentioned function is achieved, it is possible to suppress the side flow of the coolant and the side flow of the reaction gas at the same time.

[0092] (2) The back surface of the first protrusion 60 has a flat surface portion 62 that contacts the frame member 20 facing the back surface, and the back surface of the second protrusion 70 has a flat surface portion 72 that contacts the frame member 20 facing the back surface. In other words, the back surfaces of both the first protrusion 60 and the second protrusion 70 have flat surfaces 62 and 72 that contact the corresponding frame member 20.

[0093] This structure prevents the fuel gas from flowing outside the first cell flow path 31 through the space between the frame member 20 and the anode-side separator 30. Furthermore, the oxidizing gas is prevented from flowing outside the second cell flow path 41 through the space between the frame member 20 and the cathode-side separator 40. Consequently, bypass of the fuel gas and oxidizing gas can be suppressed.

[0094] (3) The anode-side separator 30 and the cathode-side separator 40 are made of resin.

[0095] According to such a configuration, the anode-side separator 30 and the cathode-side separator 40 in which the flat surfaces 62 and 72 are provided on the back surfaces of the first protrusion 60 and the second protrusion 70 can be easily formed.

[0096] (4) The first protrusion 60 has the recess 61 on the surface of the first protrusion 60. The second protrusion 70 has the recess 71 on the surface of the second protrusion 70.

[0097] In the resin separators 30 and 40, the flat surfaces 62 and 72 that abut against the frame member 20 are provided on the back surfaces of the first and second protrusions 60 and 70, causing the thickness of the separators 30 and 40 to be locally increased. Consequently, there is a risk of poor molding of the first and second protrusions 60 and 70. Consequently, the first and second protrusions 60 and 70 may not properly contact each other, or the flat surfaces 62 and 72 may not properly contact the frame member 20.

[0098] In this regard, according to the above configuration, although the first protrusion 60 and the second protrusion 70 have the flat surfaces 62 and 72 on their back surfaces, the recesses 61 and 71 on their front surfaces can suppress the occurrence of molding defects due to a local increase in thickness.

[0099] (5) The recessed portion 61 of the first cell 10A extends so as to intersect the protrusion 41b of the second cell 10B. The recessed portion 71 of the second cell 10B extends so as to intersect the protrusion 31b of the first cell 10A.

[0100] This structure restricts the protrusion 41b from entering the recess 61 of the first protrusion 60 and the protrusion 31b from entering the recess 71 of the second protrusion 70. Therefore, by appropriately contacting the protrusions 41b and 31b with the first and second protrusions 60 and 70, the surface pressure between the separators 30 and 40 and the frame member 20 can be increased. This prevents the reaction gas from flowing sideways from the slot flow paths 31 and 41 through between the separators 30 and 40 and the frame member 20.

[0101] <Change Example>

[0102] This embodiment can be implemented by modifying as follows: This embodiment and the following modified examples can be implemented in combination with each other within a range that does not technically conflict.

[0103] In the above embodiment, the recessed portion 61 of the first protrusion 60 and the recessed portion 71 of the second protrusion 70 extend so as to intersect the protrusion 41b of the supply-side connection area 43 and the protrusion 31b of the discharge-side connection area 34, respectively. However, this is not limiting. The recessed portion 61 of the first protrusion 60 and the recessed portion 71 of the second protrusion 70 may also extend along the protrusion 41b of the supply-side connection area 43 and the protrusion 31b of the discharge-side connection area 34, respectively.

[0104] In the above embodiment, the first protrusion 60 and the second protrusion 70 have portions that abut the protrusions 41b of the supply-side connection area 43 and the protrusions 31b of the discharge-side connection area 34, respectively. However, the present invention is not limited to this. The first protrusion 60 and the second protrusion 70 do not necessarily extend to the positions where they abut the protrusions 41b of the supply-side connection area 43 and the protrusions 31b of the discharge-side connection area 34, respectively.

[0105] In the above embodiment, the recessed portions 61 and 71 are formed as elongated holes. However, the shape of the recessed portions 61 and 71 may be, for example, circular in plan view.

[0106] The recessed portions 61 and 71 of the first protrusion 60 and the second protrusion 70 may be omitted as long as the first protrusion 60 and the second protrusion 70 do not cause molding defects.

[0107] In the above embodiment, the first protrusion 60 and the second protrusion 70 are formed on the anode separator 30 and the cathode separator 40, respectively, by hot pressing a resin plate containing a conductive material. However, the present invention is not limited to this. For example, the first protrusion 60 and the second protrusion 70 may be joined to the metal anode separator 30 and the cathode separator 40, respectively, which have been formed with the first slot flow path 31 and the second slot flow path 41 by stamping.

[0108] In the above embodiment, the flat surfaces 62 and 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 . However, a flat surface may be provided on the back surface of at least one of the first protrusion 60 and the second protrusion 70 .

[0109] In the above embodiment, the first protrusion 60 is provided only between the cooling channel 35 in the third direction Z and the long side 52 of the gasket 50, but the present invention is not limited thereto. The first protrusion may also be provided between the cooling channel 35 in the second direction Y and the short side 51 of the gasket 50. For example, Figure 8As shown, two first protrusions 160 and 260 are provided on the anode-side separator 30 on both sides, outboard of the supply-side manifold 311 in the third direction Z. The first protrusion 160 includes a first portion 163 and a second portion 164. The first portion 163 is located between the cooling channel 35 and the long side 52 of the gasket 50 in the third direction Z and extends closer to the supply-side manifold 311 than the cooling channel 35 in the second direction Y. 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 channel 35 and the short side 51 of the gasket 50 in the second direction Y. The first protrusion 260 extends along the third direction Z to a position outboard of the cooling channel 35 in the third direction Z. 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 channel 35 than the supply-side manifold 311. Similarly, the cathode-side separator 40 is provided with two second protrusions 170 and 270, respectively, on either side of the supply-side manifold 411 in the third direction Z. The second protrusion 170 includes a first portion 173 and a second portion 174. The first portion 173 is located between the cooling channel 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 channel 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 channel 45 and the short side 51 of the gasket 50 in the second direction Y. The second protrusion 270 extends along the third direction Z and extends to a position further outward than the cooling channel 45 in the third direction Z. The 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 path 45 than the supply-side manifold 411 .

Claims

1. A fuel cell stack comprising a plurality of stacked cells, wherein: Each battery has: Power Generation Department; A frame member provided around the power generation unit to hold the power generation unit; and a first separator and a second separator for sandwiching the power generation unit and the frame member; The first separator and the second separator each have an opposing surface facing the power generation portion and an opposite surface located on the opposite side of the opposing surface. A first groove flow path is provided on the facing surface of the first separator, and the first groove flow path is configured to allow a first reaction gas supplied to the power generation unit to flow. A second groove flow path is provided on the facing surface of the second separator, and the second groove flow path is configured to allow a second reaction gas supplied to the power generation section to flow. A cooling flow path is provided on the opposite surface of the first separator and the opposite surface of the second separator, and the cooling flow path is configured to allow a cooling medium for cooling the power generation unit to flow. When any one of the plurality of stacked cells is referred to as a first cell and a cell having a second separator stacked on the first separator of the first cell among the plurality of stacked cells is referred to as a second cell, A gasket is provided between the first separator of the first cell and the second separator of the second cell, surrounding the cooling flow path and sealing between the first separator and the second separator. The first separator of the first cell has a first protrusion, and the second separator of the second cell has a second protrusion. The first protrusion and the second protrusion are located between the cooling flow path and the gasket, and are configured to abut against each other to suppress 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 includes a flat surface portion that abuts against a frame member facing the back surface.

2. The fuel cell stack according to claim 1, wherein: The back surface of the first protrusion has a flat surface portion that contacts the frame member facing the back surface, and the back surface of the second protrusion has a flat surface portion that contacts the frame member facing the back surface.

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

4. The fuel cell stack according to claim 3, wherein: The first protrusion has a recessed portion on a surface of the first protrusion. The second protrusion has a recessed portion on a surface of the second protrusion.

5. The fuel cell stack according to claim 4, wherein: The first tank flow path has: a power generation region portion opposite to the power generation portion; a supply-side connecting region connecting the power generation region and a supply-side manifold configured to supply the first reaction gas to the first tank flow path; and a discharge-side connecting region portion connecting the power generation region portion and a discharge-side manifold configured to discharge the first reaction gas from the first tank flow path; The second tank flow path has: a power generation region portion opposite to the power generation portion; a supply-side connecting region connecting the power generation region and a supply-side manifold configured to supply the second reaction gas to the second tank flow path; and a discharge-side connecting region portion connecting the power generation region portion and a discharge-side manifold configured to discharge the second reaction gas from the second tank flow path; A plurality of protrusions extending along a plurality of grooves constituting the first groove flow path are formed on the opposite surface of the first separator. A plurality of protrusions extending along a plurality of grooves constituting the second groove flow path are formed on the opposite surface of the second separator. The first protrusion of the first cell has a portion that abuts against a portion of the plurality of protrusions of the second separator of the second cell that corresponds to the supply-side connecting region or the discharge-side connecting region. The recessed portion of the first protrusion of the first cell extends so as to intersect the protrusion of the second separator of the second cell.

6. The fuel cell stack according to claim 4, wherein: The first tank flow path has: a power generation region portion opposite to the power generation portion; a supply-side connecting region connecting the power generation region and a supply-side manifold configured to supply the first reaction gas to the first tank flow path; and a discharge-side connecting region portion connecting the power generation region portion and a discharge-side manifold configured to discharge the first reaction gas from the first tank flow path; The second tank flow path has: a power generation region portion opposite to the power generation portion; a supply-side connecting region connecting the power generation region and a supply-side manifold configured to supply the second reaction gas to the second tank flow path; and a discharge-side connecting region portion connecting the power generation region portion and a discharge-side manifold configured to discharge the second reaction gas from the second tank flow path; A plurality of protrusions extending along a plurality of grooves constituting the first groove flow path are formed on the opposite surface of the first separator. A plurality of protrusions extending along a plurality of grooves constituting the second groove flow path are formed on the opposite surface of the second separator. The second protrusion of the second cell has a portion that abuts against a portion of the plurality of protrusions of the first separator of the first cell that corresponds to the supply-side connecting region or the discharge-side connecting region. The recessed portion of the second protrusion of the second cell extends so as to intersect the protrusion of the first separator of the first cell.

7. A separator for a fuel cell, the separator being configured to be arranged facing a power generation unit of the fuel cell and a frame member provided around the power generation unit to hold the power generation unit, wherein: The separator of the fuel cell has an opposing surface configured to face the power generation unit and an opposite surface located on the opposite side of the opposing surface. A groove flow path is provided on the facing surface, and the groove flow path is configured to allow a reaction gas supplied to the power generation unit to flow. A cooling flow path is provided on the opposite surface, and the cooling flow path is configured to allow a cooling medium to flow to cool the power generation unit. A mounting portion on which a gasket can be mounted is provided on the opposite surface. The gasket surrounds the cooling flow path and seals between the separator and other separators stacked on the separator. A protrusion is provided on the opposite surface, the protrusion being configured to be located between the cooling flow path and the gasket, and the protrusion being configured to suppress the cooling medium from flowing outside the cooling flow path by protruding in a manner abutting against the other separator. The rear surface of the protrusion has a flat surface portion configured to abut against the frame member.

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