JP6981317B2 - Fuel cell stack - Google Patents

Description

The present invention relates to a fuel cell stack.

The fuel cell stack is configured by stacking a plurality of fuel cell cells, and each fuel cell has a membrane electrode assembly sandwiched between a cathode separator and an anode separator. When sandwiching the membrane electrode assembly with a separator, a method has been proposed in which the membrane electrode assembly is surrounded by a frame-shaped resin sheet, and then the membrane electrode assembly is sandwiched together with the resin sheet by both cathode and anode separators. (For example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2015-88293

The fuel cell stack is installed so that the cell stacking direction of the fuel cell cells is in a horizontal horizontal posture, but the fuel cell stack is not always in the horizontal posture. For example, in a fuel cell mounted on a moving body such as a vehicle, one end side in the cell stacking direction, for example, the front end of the fuel cell stack is below in the traveling process of the vehicle on an uphill road or the parking process on a sloped parking road surface. , The rear end of the fuel cell stack on the other end side in the cell stacking direction may be inclined so as to be upward. In such an inclined posture, the manifold for supplying and discharging fuel gas and oxide gas that penetrates the fuel cell stack in the cell stacking direction in the outer edge region of the membrane electrode assembly is also inclined, so that the water that reaches the manifold, specifically the generated water, is also inclined. It is possible that water that has permeated the electrolyte membrane (specifically, water vapor) travels through the manifold and accumulates on the lower side of the slope. When water is accumulated in the manifold in this way, in the fuel cell on the lower side of the slope where water is accumulated, water may permeate excessively into the cell, and the power generation performance of the fuel cell may not be maintained. The same applies when the fuel cell stack is tilted so that the rear end is at the bottom and the fuel cell front end is at the top. For these reasons, it has been required to maintain the power generation performance of the fuel cell when the fuel cell stack is tilted.

The present invention has been made in view of the above-mentioned problems, and can be realized as the following forms.

(1) One form of a fuel cell stack is a fuel cell in which a film electrode joint surrounded by a frame-shaped resin sheet is sandwiched together with the resin sheet by both cathode side and anode side separators in the outer edge region of the film electrode joint. A fuel cell stack in which a plurality of cells are stacked, the seat side manifold hole for gas discharge provided in the outer edge region of the resin sheet, and the seat side manifold hole opening in the outer edge region of both separators. A separator-side manifold hole for gas discharge provided with an opening shape larger than the shape forms a gas discharge manifold by laminating the fuel cell, and the fuel cell has a posture in which the fuel cell stack is installed. Has a notch formed by cutting out the bottom peripheral wall of the seat-side manifold hole in a part of the bottom portion of the gas discharge manifold in the above, and the notch is the separator-side manifold hole of both separators. The peripheral wall on the bottom side is projected from the bottom of the notch portion toward the inside of the gas discharge manifold in the partial region, and is continuously arranged in the cell stacking direction of the fuel cell.

In this form of fuel cell stack, the water that has entered the gas discharge manifold is discharged as follows. The water that has entered the gas discharge manifold stays as a water mass on the bottom side of the gas discharge manifold. The water mass that stays so as to overlap the notch forms a band along the notch. In the notch, the peripheral wall on the bottom side of the manifold hole on the separator side protrudes from the bottom of the notch, but since the manifold hole on the separator side has a larger opening shape than the manifold hole on the seat side, the peripheral wall on the bottom side of the manifold hole on the separator side is formed. In the notch, it is lower than the bottom peripheral wall of the seat side manifold hole of the notch opening. Therefore, the peripheral wall on the bottom side of the separator-side manifold hole does not serve as a flow resistance when the band-shaped water mass flows along the notch portion from the peripheral wall to the notch opening. Therefore, when the front end of the fuel cell stack is tilted and the rear end of the fuel cell stack is top with respect to the cell height direction perpendicular to the cell stacking direction, the notches continuously arranged in the cell stacking direction are also tilted. However, the band-shaped water mass in this notch from the peripheral wall on the bottom side of the separator-side manifold hole to the opening of the notch can flow out along the line of the inclined notch and be discharged from the gas discharge manifold. Due to the discharge of water from the gas discharge manifold, it is possible to prevent a situation in which excessive water is accumulated on the front end side of the fuel cell stack. The same applies when the rear end of the fuel cell stack is tilted down and the front end of the fuel cell stack is up. Therefore, according to this form of the fuel cell stack, it is possible to maintain the power generation performance of the fuel cell even when the fuel cell stack is tilted.

The present invention can be realized in various aspects. For example, it can be realized in the form of a stop control method for the fuel cell stack.

It is explanatory drawing which shows the schematic structure of the fuel cell which has the fuel cell stack which concerns on embodiment. It is explanatory drawing which shows by disassembling the fuel cell in one Embodiment of this invention. It is explanatory drawing which enlarges and outlines the air gas discharge manifold in a fuel cell stack in a cell laminated state. It is explanatory drawing which shows the gas discharge manifold in the cross-sectional view along line 4-4 of FIG. 3 in the situation where a plurality of fuel cell cells are stacked. It is explanatory drawing which shows the gas discharge manifold in the cross-sectional view along the line 5-5 of FIG. 3 in the situation where a plurality of fuel cell cells are stacked. It is explanatory drawing which shows the gas discharge manifold in the cross-sectional view along line 6-6 of FIG. 3 in the situation where a plurality of fuel cell cells are stacked. It is explanatory drawing which shows the gas discharge manifold in the cross-sectional view along line 7-7 of FIG. 3 in the situation where a plurality of fuel cell cells are laminated. It is explanatory drawing which shows typically the behavior of the water which reached the gas discharge manifold for air discharge. It is explanatory drawing which shows typically the situation that the fuel cell is tilted so that the front end of the fuel cell of the fuel cell is vertically lower.

FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell 100 having a fuel cell stack 110 according to an embodiment. The fuel cell 100 is configured by sandwiching a fuel cell stack 110 in which a plurality of fuel cell cells 110S are stacked by a pair of end plates 170F and 170E. The fuel cell 100 has a terminal plate 160F with an insulating plate 165F interposed between the end plate 170F on one end side thereof and the fuel cell 110S. Hereinafter, one end side of the fuel cell 100 in which the end plate 170F is arranged is referred to as a front end side for convenience, and the other end side on the right side of the paper surface in the drawing is referred to as a rear end side.

The fuel cell 100 also has a terminal plate 160E on the rear end side with an insulating plate 165E on the rear end side interposed between the end plate 170E on the rear end side and the fuel cell 110S. The fuel cell 110S, the terminal plates 160F and 160E, the insulating plates 165F and 165E, and the end plates 170F and 170E each have a plate structure having a substantially rectangular outer shape, and the long side is in the x-axis direction ( The short sides are arranged along the y-axis direction (vertical direction, vertical direction) in the horizontal direction. The fuel cell 110S is stacked along the z-axis direction between the end plates on the front end side and the rear end side, and the fuel cell 100 is horizontally stacked in the stacking direction (z-axis direction) of the fuel cell 110S as shown in the figure. It is installed in a vehicle or the like so that it has a horizontal posture that overlaps in the direction.

The fuel cell 100 has an oxygen-containing oxide gas air supply manifold 116 and discharge manifold 117, and a fuel gas hydrogen gas supply manifold 118 and discharge manifold 119 on the end plate 170F on the front end side. And prepare. In the figure, the air supply manifold 116 is arranged in front of the paper surface of the hydrogen gas supply manifold 118, and the air discharge manifold 117 is arranged in the back side of the paper surface of the hydrogen gas supply manifold 118. There is.

Each fuel cell 110S in the fuel cell stack 110 guides the air sent from the supply manifold 116 to the inside of the cell and the adjacent cell, and discharges the excess air that has passed through the cell to the discharge manifold 117. The same applies to hydrogen gas, and the fuel cell 110S guides the hydrogen gas sent from the supply manifold 118 to the inside of the cell and the adjacent cell, and discharges the surplus hydrogen gas that has passed through the cell to the discharge manifold 119. do. That is, air and hydrogen gas are sent from the end plate 170F side through the separate supply manifolds and returned from the fuel cell 110S on the end plate 170E side, and the surplus is for individual discharge of the end plate 170F. It is discharged from the manifold. A supply manifold 116 for air and a discharge manifold 117 may be provided on the side of the end plate 170F, and a supply manifold 118 for hydrogen gas and a discharge manifold 119 may be provided on the side of the end plate 170E. Even in this way, the air and the hydrogen gas are returned and discharged, respectively. The air is discharged together with the generated water.

The supply manifold 116 and the like described above are manifolds outside the cell and communicate with the gas manifold inside the cell described later. The fuel cell 100 also has a cooling water supply / discharge manifold, but since this cooling water supply / discharge manifold is not directly related to the gist of the present invention, the illustration thereof is omitted in FIG.

The terminal plate 160F on the front end side and the terminal plate 160E on the rear end side are current collector plates for the generated power of each fuel cell 110S, and output the power collected from the current collector terminals (not shown) to the outside.

FIG. 2 is an explanatory diagram showing the fuel cell 110S according to the embodiment of the present invention in an exploded manner. The fuel cell 110S is a polymer electrolyte fuel cell that generates electricity by being supplied with hydrogen and oxygen. The fuel cell 110S includes a power generation body 10, a resin sheet 20, a cathode side separator 40a, and an anode side separator 40b.

The power generation body 10 includes an electrolyte membrane (not shown), a catalyst layer (not shown) formed adjacent to both sides of the electrolyte membrane, and a gas diffusion layer (not shown). The electrolyte membrane is a solid polymer thin film that exhibits good proton conductivity in a wet state. The electrolyte membrane is composed of, for example, an ion exchange membrane of a fluororesin. The catalyst layer includes a catalyst that promotes a chemical reaction between hydrogen and oxygen, and carbon particles that carry the catalyst. Then, by forming a catalyst layer on both membrane surfaces of the electrolyte membrane, a membrane electrode assembly (MEA: Membrane Electrode Associate Assembly) can be obtained.

The gas diffusion layer is provided adjacent to the surface on the catalyst layer side. The gas diffusion layer is a layer that diffuses the reaction gas used for the electrode reaction along the surface direction of the electrolyte membrane, and is composed of a porous base material for the diffusion layer. As the base material for the diffusion layer, a porous base material having conductivity and gas diffusivity such as a carbon fiber base material, a graphite fiber base material, and a foamed metal is used. The electrolyte membrane, the catalyst layer, and the gas diffusion layer are collectively referred to as a membrane electrode gas diffusion layer junction (MEGA: Membrane Electrode Gass-diffusion-layer Assembly).

The resin sheet 20 is a frame-shaped resin member that surrounds the entire periphery of the power generation body 10 including the membrane electrode assembly. As the resin member, for example, polyethylene terephthalate (PET) is used in this embodiment. However, as the resin member, various other thermoplastic resin members such as polypropylene and polyethylene and rubber materials can also be used. The resin sheet 20 is provided with an opening 21 in the central region for surrounding and accommodating the power generation body 10, and the sheet side for gas supply is provided on both sides of the opening 21, specifically, on both sides of the opening 21 along the x-axis direction. It has a manifold hole 30ai, a seat-side manifold hole 30ao for gas discharge, and a cooling manifold hole 31.

The seat side manifold hole 30ai for gas supply and the seat side manifold hole 30ao for gas discharge are formed side by side in the y-axis direction, and each seat side manifold hole is for a reaction gas (hydrogen gas, air). It overlaps with one of the supply manifold 116, the discharge manifold 117, the supply manifold 118, and the discharge manifold 119 described above, and the reaction gas flows in the direction (z-axis direction) penetrating the resin sheet 20. The cooling manifold hole 31 overlaps with the cooling water supply / discharge manifold (not shown in FIG. 1), and the cooling water flows in the direction (z-axis direction) penetrating the resin sheet 20.

The resin sheet 20 includes a plurality of gas supply / discharge passages 50 between the seat-side manifold hole 30ai and the opening 21 and between the seat-side manifold hole 30ao and the opening 21. The gas supply / discharge passage 50 is formed as a sheet through hole having a long diameter in a straight path along the x-axis direction. The gas supply / discharge passage 50 serves as a gas passage path for supplying gas to the power generation body 10 on the side of the seat side manifold hole 30ai, and for gas discharge from the power generation body 10 on the side of the seat side manifold hole 30ao. It becomes a gas passage of. The gas supply / discharge path 50 may be a concave groove-shaped long-diameter gas supply / discharge path. In this case, by forming the gas supply / discharge passage 50 as a sheet through hole, the thickness of the resin sheet 20 and the thickness of the fuel cell 110S are reduced as compared with the case where the gas supply / discharge passage has a concave groove shape. be able to.

The resin sheet 20 has water repellency on the sheet surface in the region where the seat side manifold hole 30ai and the seat side manifold hole 30ao are formed, that is, the outer edge region of the power generator 10 due to the characteristics peculiar to the resin member described above. In this case, the surface of the outer edge region of the resin sheet 20 or the entire surface of the sheet may be subjected to water repellent treatment such as plasma irradiation, chemical vapor deposition, ultraviolet irradiation, or etching in the process of manufacturing the resin sheet 20.

In addition, the resin sheet 20 has a notch 32 in a part of the bottom surface of the sheet-side manifold hole 30ao for gas discharge. The cutout portion 32 is formed by cutting out the bottom peripheral side peripheral wall of the seat side manifold hole 30ao on the side away from the gas supply / discharge passage 50. As shown in FIG. 1, the base on which the notch 32 is formed is the bottom on the vertically lower side in the posture in which the fuel cell 100 is horizontally installed. The notch 32 will be described later in consideration of the relationship between the separators 40a and 40b and the separator-side manifold holes 30bo for discharging gas.

The pair of separators 40a and 40b are laminated on the resin sheet 20 so as to sandwich the power generation body 10 including the membrane electrode assembly together with the resin sheet 20 in the outer edge region of the power generation body 10. Both the separators 40a and 40b are formed by press-molding, for example, a metal plate made of stainless steel, titanium, or an alloy thereof. Therefore, the separators 40a and 40b have hydrophilicity on their surfaces due to the properties peculiar to the metal material described above. In this case, the surface of the separator in the outer edge region of the separators 40a and 40b and the entire surface of the separator may be subjected to hydrophilicity-imparting treatment such as plasma irradiation, chemical vapor deposition, ultraviolet irradiation, or etching in the manufacturing process of the separators 40a and 40b.

In the present embodiment, the separator 40a is a separator on the cathode side, and the separator 40b is a separator on the anode side. Both the separators 40a and 40b have a separator-side manifold hole 30bi for gas supply, a separator-side manifold hole 30bo for gas discharge, and a cooling manifold hole 31 in the outer edge region of the power generator 10. The cooling manifold hole 31 overlaps with the cooling manifold hole 31 of the resin sheet 20, and the cooling water flows in the direction (z-axis direction) penetrating both the separators 40a and 40b. The separators 40a and 40b form an inter-cell cooling flow path between the overlapping fuel cell 110S, but since the inter-cell cooling flow path is not directly related to the gist of the present invention, the illustration thereof is shown in FIG. Is omitted.

The separator side manifold holes 30bi and the separator side manifold holes 30bo of the separators 40a and 40b are used for supplying and discharging reaction gas (hydrogen gas, air) to the membrane electrode assembly of the generator 10, and are used for supplying and discharging the reaction gas (hydrogen gas, air) to the sheet side manifold of the resin sheet 20. It overlaps the hole 30ai and the separator side manifold hole 30bo, respectively. In the present embodiment, in the figure, each of the above-mentioned manifold holes of the resin sheet 20 and the separators 40a and 40b has a rectangular shape, but a triangular, polygonal, or irregularly shaped opening-shaped manifold hole may be used. Regardless of the shape of the separator side manifold hole 30bi and the separator side manifold hole 30bo, the opening shape is larger than the seat side manifold hole 30ai and the seat side manifold hole 30ao of the resin sheet 20 described above. There is. In the present embodiment, the manifold formed by overlapping the seat side manifold hole 30ao and the separator side manifold hole 30bo is hereinafter referred to as a gas discharge manifold 30. In the gas discharge manifold 30, the sheet-side manifold hole 30ao for gas discharge of the resin sheet 20 and the separator-side manifold hole 30bo for gas discharge of both the separators 40a and 40b are overlapped by stacking the fuel cell 110S. It is formed by.

Both the separators 40a and 40b are provided with a flow path 41 from the separator-side manifold hole 30bi on the supply side of the reaction gas (hydrogen gas, air) to the separator-side manifold hole 30bo on the discharge side. The flow path 41 is formed by the unevenness of the separators 40a and 40b, and has a flow path configuration of a plurality of lines branched from the distribution flow path 42 in the vicinity of the separator side manifold hole 30bi on the supply side. Then, the flow path 41 merges in the vicinity of the separator side manifold hole 30bo on the discharge side to form a merging flow path 43. The distribution flow path 42 overlaps and communicates with the gas supply / discharge passage 50 of the resin sheet 20 in the vicinity of the separator side manifold hole 30bi on the supply side, and the merging flow path 43 is made of resin in the vicinity of the separator side manifold hole 30bo on the discharge side. It overlaps with the gas supply / discharge passage 50 of the sheet 20 and communicates with the gas supply / discharge passage 50. As a result, the reaction gas (hydrogen gas, air) that has flowed into the separator-side manifold hole 30bi on the supply side and the sheet-side manifold hole 30ai of the resin sheet 20 that overlaps the separator-side manifold hole 30bi is distributed from the gas supply / discharge passage 50 of the resin sheet 20 to the distribution flow path. It passes through 42, flows through the flow paths 41 of a plurality of lines, and is supplied to the power generation body 10. The reaction gas (hydrogen gas, air) that has passed through the flow path 41 passes through the gas supply / discharge passage 50 from the merging flow path 43, and is the sheet-side manifold of the separator-side manifold hole 30bo on the discharge side and the resin sheet 20 that overlaps the hole 30bo. It is discharged from the hole 30ao.

FIG. 3 is an explanatory view showing an enlarged view of the air gas exhaust manifold 30 in the fuel cell stack 110 in a cell-stacked state. The gas discharge manifold 30 is a manifold hole for air discharge on the lower left side in the fuel cell 110S of FIG. FIG. 4 is an explanatory view showing a gas discharge manifold 30 in a cross-sectional view along line 4-4 of FIG. 3 in a situation where a plurality of fuel cell 110S are stacked. FIG. 5 is an explanatory view showing a gas discharge manifold 30 in a cross-sectional view along line 5-5 of FIG. 3 in a situation where a plurality of fuel cell 110S are stacked. FIG. 6 is an explanatory view showing a gas discharge manifold 30 in a cross-sectional view along line 6-6 of FIG. 3 in a situation where a plurality of fuel cell 110S are stacked. FIG. 7 is an explanatory view showing a gas discharge manifold 30 in a cross-sectional view along line 7-7 of FIG. 3 in a situation where a plurality of fuel cell 110S are stacked.

As shown in FIG. 3, the sheet-side manifold hole 30ao of the resin sheet 20 and the separator-side manifold holes 30bo of the separators 40a and 40b overlap to form a gas discharge manifold 30. The cathode side separator 40a, the resin sheet 20, and the anode side separator 40b are in a laminated state. Since the opening shape of the sheet-side manifold hole 30ao of the resin sheet 20 is smaller than the opening shape of the separator-side manifold hole 30bo as described above, the resin sheet 20 is formed at the bottom of the gas discharge manifold 30. The tip is located inside the gas discharge manifold 30 from the tips of both the anode side and cathode side separators. That is, in the resin sheet 20, as shown in FIG. 4, the resin sheet 20 has the bottom wall surface 30 at of the bottom wall in the seat side manifold hole 30ao in the cell height direction (y-axis direction) perpendicular to the cell stacking direction. It protrudes from the bottom wall surface 30bt of the bottom side peripheral wall in the hole 30bo. Further, in the resin sheet 20, the side wall surface 30as of the seat side manifold hole 30ao is formed from the side wall surface 30bs of the separator side manifold hole 30bo along the horizontal direction (x-axis direction) as shown in FIGS. 6 and 7. It is protruding. The same applies to the ceiling side peripheral wall in the separator side manifold hole 30bo. Due to the protrusion of the peripheral wall of the manifold hole of the resin sheet 20, contact between the separator 40a facing each other across the resin sheet 20 and the peripheral wall of the manifold hole of the separator 40b due to bending is avoided, and insulation between the separators is ensured.

The separators 40a and 40b are bent so as to be away from the resin sheet 20 around the hole peripheral wall of the separator side manifold hole 30bo, and as shown in FIG. 4, the side and side wall surfaces 30as of the bottom wall surface 30at of the sheet side manifold hole 30ao. On the side, a gap recess 23 is formed on the front and back sheet surfaces of the resin sheet 20. The gap recess 23 is a recess whose bottom side is inclined, and in a single fuel cell 110S, it is a recess up to the bottom wall surface 30bt or the side wall surface 30bs of the separators 40a and 40b. On the other hand, in the state where the fuel cell 110S is laminated, it is formed as a recess up to the bottom wall surface 30 at or the side wall surface 30 as of the resin sheet 20. In the fuel cell 110S of the present embodiment, in order to reduce the amount of liquid water retained in the gap recess 23, the depth of the gap recess 23 of the cell alone is set to about 1.0 to 1.4 mm, and a resin sheet is used. By setting the protrusion length D of 20 to a depth of about 0.6 to 1.0 mm, a water retention space of about 1.6 to 2.4 mm is provided as a gap recess 23 in a state where the fuel cell 110S is laminated. rice field. Since the separators 40a and 40b forming the gap recess 23 have hydrophilicity on the surface and the resin sheet 20 having the gap recess 23 on the sheet surface has water repellency, the fuel cell 110S has a gap recess. In the surrounding area of the place 23, the water repellency is exhibited on the bottom side of the recess and the hydrophilicity is exhibited on the opening side of the recess. The depth dimension of the gap recess 23 may be appropriately set according to the inter-cell pitch, the size of the gas discharge manifold 30, or the maximum gas supply / discharge amount of the reaction gas. Not limited.

The gas supply / discharge passage 50 of the resin sheet 20 overlaps with the separators 40a and 40b, leaving the gas introduction portion 51 in the vicinity of the seat side manifold hole 30ao. Of the separators 40a and 40b, the cathode side separator 40a has a merging flow path 43 in the vicinity of the separator side manifold hole 30bo as shown in FIG. 2, and the merging flow path 43 is as shown in FIG. In addition, it overlaps with the gas supply / discharge path 50. Therefore, the gas supply / discharge passage 50 is involved in the air discharge in the fuel cell 110S in the air gas discharge manifold 30 shown in FIG. 3 between the separator 40a on the cathode side and the resin sheet 20. On the other hand, since the anode-side separator 40b does not have a merging flow path 43 in the vicinity of the separator-side manifold hole 30bo for air discharge, the gas supply / discharge passage 50 does not participate in air discharge. The involvement of the gas supply / discharge passage 50 in the gas supply / discharge is the same in the gas manifold for supplying air and the gas manifold for supplying / discharging hydrogen gas. The hydrogen gas that has flowed into the gas manifold for supply due to the involvement of gas supply / discharge in the gas supply / discharge passage 50 passes through the flow path 41 of the separator 40b on the anode side and is a membrane electrode assembly of the power generator 10. Is supplied to the gas discharge manifold 30 and discharged from the gas discharge manifold 30. Further, the air that has flowed into the gas manifold for supply passes through the flow path 41 of the separator 40a on the cathode side, is supplied to the membrane electrode assembly of the power generator 10, and is discharged from the gas discharge manifold 30. In the resin sheet 20 of the present embodiment, as described above, the gas supply / discharge passage 50 involved in the gas supply / discharge is provided in the cell height direction (as shown in FIG. 3) with respect to the bottom wall surface 30bt of the separator side manifold hole 30bo. It is provided to a low position in the y-axis direction).

Between the adjacent fuel cell 110S, a gasket 60 surrounding the gas discharge manifold 30 is provided between the separator 40a of one fuel cell 110S and the separator 40b of the other fuel cell 110S. .. The gasket 60 is adhered to the separator 40a, and the gas discharge manifold 30 is sealed between the cells by laminating the fuel cell 100. The gasket 60 is formed of, for example, silicone rubber. A cooling flow path through which cooling water flows from the cooling manifold hole 31 is formed between adjacent fuel cell cells 110S, and even in this cooling flow path, the gasket 60 seals the cooling flow path.

As shown in FIG. 3, the notch 32 of the resin sheet 20 in the seat-side manifold hole 30ao for air discharge is away from the center of the bottom wall surface 30 at from the gas introduction portion 51 which is the air outlet to the gas discharge manifold 30. The notches are formed so as to be separated from each other, and in the laminated state of the fuel cell 110S, they are continuously arranged as a single line in the cell stacking direction. In FIG. 3, the notch portion 32 is magnified for the purpose of clearly indicating the notch portion 32. In the fuel cell stack 110 of the present embodiment, the notch width of the notch portion 32 is 2 to 5 mm, and the notch depth is 0.3 to 0.6 mm in consideration of the depth of the gap recess 23 described above. did. By adjusting the dimensions in this way, as shown in FIGS. 3 and 5, the cutout portion 32 has a cutout portion bottom portion 32t of the bottom wall surface 30bt of the bottom side peripheral wall of the separator side manifold hole 30bo of both separators 40a and 40b. Protruding from. Therefore, as shown in FIG. 3, the bottom wall surface 30bt of the bottom side peripheral wall of the separator side manifold hole 30bo at the portion protruding from the bottom portion 32t of the notch portion is continuously arranged in the cell stacking direction.

In the fuel cell stack 110 of the present embodiment described above, even if water W reaches the seat side manifold hole 30ao and the separator side manifold hole 30bo that overlap each other so as to form the gas discharge manifold 30 for air discharge, this water W is retained in the gap recess 23 on the front and back sheet surfaces of the resin sheet 20 at the bottom of the gas discharge manifold 30. The water W reaching the gas discharge manifold 30 is generated water mixed in the exhaust air from the gas supply / discharge passage 50. The fuel cell stack 110 maintains this water retention state by the resin sheet 20 whose tip is located inside at the bottom of the gas discharge manifold 30. If the amount of water W reaching the gas discharge manifold 30 is small, the fuel cell stack 110 transfers the water W retained in the gap 23 to the gas on the lower side (−y axis direction) in the vertical direction shown in FIG. It is guided to the membrane electrode assembly of the power generation body 10 from the merging flow path 43 and the flow path 41 shown in FIG. 7 via the supply / discharge path 50. Even if the amount of water W reaching the gas discharge manifold 30 for discharging air increases, the fuel cell stack 110 discharges water W as follows when the fuel cell 100 is tilted.

FIG. 8 is an explanatory diagram schematically showing the behavior of the water W reaching the gas discharge manifold 30 for air discharge. When a large amount of water W exceeding the water retention amount in the gap recess 23 of each cell reaches the gas discharge manifold 30 in each fuel cell 110S, the water W discharges gas as shown in the upper part of FIG. It stays as a water mass on the bottom side of the fuel cell 30. As shown by the white arrow in the figure, the water W staying in this way flows from the gap recess 23 in the fuel cell 110S toward the notch 32, or from the portion overlapping the opening of the notch 32 to the notch 32. As shown in the lower part of FIG. 8, it flows and becomes a band-shaped water mass along the line of the cutouts 32.

In the notch 32, the bottom wall surface 30bt of the bottom peripheral wall of the separator side manifold hole 30bo protrudes from the notch bottom 32t, but the separator side manifold hole 30bo has a larger opening shape than the seat side manifold hole 30ao, so that the separator side The bottom side peripheral wall of the manifold hole 30bo is lower than the notch opening, that is, the bottom wall surface 30at in the notch 32. Therefore, as shown in FIGS. 3 and 8, the water W of the band-shaped water mass between the bottom wall surface 30bt of the peripheral wall and the opening of the notch is along the line of the notch 32 in the bottom side peripheral wall of the separator side manifold hole 30bo. It does not become a resistance of the flow when it flows.

FIG. 9 is an explanatory diagram schematically showing a situation in which the fuel cell 100 is tilted so that the front end of the fuel cell 100 is vertically downward. The inclined posture of the fuel cell 100 shown in the figure may occur in the process in which the vehicle equipped with the fuel cell 100 is traveling on an uphill road or parked on the inclined road surface. The manifold 30 is also tilted. In such an inclined posture, the notch 32 continuously arranged in the cell stacking direction is also inclined, and in this notch 32, the strip-shaped water between the bottom wall surface 30bt of the bottom peripheral wall of the separator side manifold hole 30bo and the opening of the notch 32. As shown by the white arrow in the figure, the water W of the lump flows out along the arrangement of the inclined notches 32 and is discharged from the gas discharge manifold 30. Due to the discharge of the water W from the gas discharge manifold 30, it is unlikely that the water W will be excessively accumulated on the front end side of the fuel cell. The same applies to the case where the rear end of the fuel cell of the fuel cell 100 is tilted vertically downward and the front end of the fuel cell is upward. Therefore, according to the fuel cell stack 110 of the present embodiment, it is possible to maintain the power generation performance of the fuel cell 110S even when the fuel cell stack 110 is tilted.

In the fuel cell stack 110 of the present embodiment, even when the fuel cell 100 is in the horizontal posture, the water W formed into a band-shaped water mass in the notch 32 due to the exhaust air flowing through the gas discharge manifold 30 is directed to the downstream side. Extrude. As a result, water W is less likely to remain in the gas discharge manifold 30. Therefore, since the residual water can be prevented from freezing while the fuel cell 100 is stopped in a cold environment, the startability in a cold environment is improved.

The fuel cell stack 110 of the present embodiment has water repellency on the sheet surface of the formation region of the seat side manifold hole 30ao in the resin sheet 20 constituting the gas discharge manifold 30, and the separator side manifold hole 30bo in the separators 40a and 40b. The surface of the separator in the formation region is hydrophilic. Therefore, the water W held in the gap recesses 23 on both sides of the resin sheet 20 in the gas discharge manifold 30 becomes a band-shaped water mass and is taken by the water W flowing down along the notch 32, and the gap recesses. It is drained from the place 23. From this point as well, it is useful for maintaining the power generation performance when the fuel cell stack 110 is tilted.

In the fuel cell stack 110 of the present embodiment, the peripheral walls of the separator side manifold holes 30bo in the separators 40a and 40b on both sides of the resin sheet 20 face each other directly in the formation region of the notch 32. However, since the notch width of the notch portion 32 is sufficiently small, it is possible to avoid contact between the peripheral walls of the manifold holes in the separators 40a and 40b due to bending, and it is possible to secure insulation between the separators even in the formation region of the notch portion 32.

In the fuel cell stack 110 of the present embodiment, as shown in FIG. 3, the notch 32 is formed so as to be far from the center of the bottom wall surface 30 at from the gas supply / discharge passage 50, and therefore for gas discharge from the gas supply / discharge passage 50. The water W that has been retained in the gap 23 can be moved to the side of the notch 32 by the air blown out to the manifold 30. Therefore, the collection of water W to the formed portion of the cutout portion 32 is promoted, and the above-mentioned discharge efficiency of water W is enhanced.

As shown in FIG. 3, the fuel cell stack 110 of the present embodiment provides the gas supply / discharge passage 50 at a position lower than the bottom wall surface 30bt of the separator side manifold hole 30bo in the cell height direction (y-axis direction). The water W retained in the gap 23 can be reliably guided to the power generation body 10 via the gas supply / discharge passage 50.

The fuel cell stack 110 of the present embodiment guides the water W retained in the gap recess 23 to the membrane electrode assembly of the power generator 10 via the gas supply / discharge passage 50, but the amount thereof is retained in the gap recess 23. Limited to a small amount of water. Therefore, according to the fuel cell stack 110 of the present embodiment, the humidification of the power generation body 10 by the water W retained in the gap recess 23 is not excessive, and the power generation performance of the fuel cell 110S is inadvertently deteriorated. Will not come.

The present invention is not limited to the above-described embodiment, and can be realized with various configurations within a range not deviating from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each embodiment described in the column of the outline of the invention are for solving a part or all of the above-mentioned problems, or one of the above-mentioned effects. It is possible to replace or combine as appropriate to achieve the part or all. Further, if the technical feature is not described as essential in the present specification, it can be appropriately deleted.

In the above-described embodiment, the gap recess 23 is also formed on the side wall and the ceiling wall of the gas discharge manifold 30, but the gap recess 23 between the side wall and the ceiling wall may be omitted.

In the above-described embodiment, all the fuel cell 110S laminated between the end plate 170F and the end plate 170E are used as cells having the notch 32, but the present invention is not limited to this. For example, the fuel cell 110S excluding a predetermined range on the end plate side (for example, 2 to 5% of the number of stacked cells) is a fuel cell having a notch 32, and the fuel cell 110S in a predetermined range on the end plate side is used. May be a fuel cell without a notch 32.

In the above-described embodiment, the notch 32 is formed at the bottom of the seat side manifold hole 30ao in the resin sheet 20 in the gas discharge manifold 30 for air discharge, but the resin sheet 20 is also formed in the hydrogen gas discharge manifold. The cutout portion 32 may be formed in the seat side manifold hole 30ao.

In the above-described embodiment, in the gas discharge manifold 30 for air discharge, a notch 32 is formed at the bottom of the seat side manifold hole 30ao in the resin sheet 20, but two notches 32 or two cuts 32 are formed at the bottom. Multiple muscles may be formed.

In the above-described embodiment, the fuel cell 100 is installed in a vehicle or the like so that the stacking direction of the fuel cell 110S overlaps in the horizontal direction, and the gas discharge manifold 30 extends horizontally, but the present invention is not limited to this. .. For example, it can be applied to the fuel cell stack 110 in which the gas discharge manifold 30 is inclined from the front end to the rear end of the stack in a situation where the fuel cell 100 is in a horizontal position.

10 ... Generator 20 ... Resin sheet 21 ... Opening 23 ... Gap recess 30 ... Gas exhaust manifold 30ai ... Seat side manifold hole 30ao ... Seat side manifold hole 30as ... Side wall surface 30at ... Bottom wall surface 30bi ... Separator side manifold hole 30bo ... Separator side manifold hole 30bs ... Side wall surface 30bt ... Bottom wall surface 31 ... Cooling manifold hole 32 ... Notch 32t ... Notch bottom 40a ... Separator 40b ... Separator 41 ... Flow path 42 ... Distribution flow path 43 ... Confluence flow path 50 ... Gas supply / exhaust passage 51 ... Gas introduction part 60 ... Gasket 100 ... Fuel cell 110 ... Fuel cell stack 110S ... Fuel cell cell 116 ... Supply manifold 117 ... Discharge manifold 118 ... Supply manifold 119 ... Discharge manifold 160E ... Terminal Plate 160F ... Terminal plate 165E ... Insulation plate 165F ... Insulation plate 170E ... End plate 170F ... End plate D ... Overhang length W ... Water

Claims (1)

A fuel cell stack consisting of a plurality of fuel cell cells in which a membrane electrode assembly surrounded by a frame-shaped resin sheet is sandwiched between the cathode side and anode side separators in the outer edge region of the membrane electrode assembly together with the resin sheet. There,
A sheet-side manifold hole for gas discharge provided in the outer edge region of the resin sheet, and a gas discharge separator provided in the outer edge region of both separators with an opening shape larger than the opening shape of the sheet-side manifold hole. The side manifold holes form a gas discharge manifold by stacking the fuel cell cells.
The fuel cell is
It has a notch formed by cutting out the bottom peripheral wall of the seat side manifold hole in a part of the bottom surface of the gas discharge manifold in the posture in which the fuel cell stack is installed.
The notch is
The peripheral wall on the bottom side of the separator-side manifold hole of both separators is projected from the bottom of the notch toward the inside of the gas discharge manifold in the partial region, and is continuous in the cell stacking direction of the fuel cell. Lined up,
Fuel cell stack.

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