JP6645765B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack.

  In some cases, stagnant water is generated upstream of the fuel gas discharge passage provided in the fuel cell stack. In order to discharge such stagnant water, a configuration in which a drain pipe is provided in the fuel gas discharge channel is known. Specifically, the opening end on the suction side of the drain pipe is disposed upstream of the fuel gas discharge flow path, and the opening end on the discharge side is connected to a portion depressurized by the back pressure valve. With such a connection, a pressure difference is generated at both ends of the drainage pipe. This pressure difference causes the retained water to be sucked and discharged (Patent Document 1).

JP 2001-266925 A

  In the case of the above prior art, it is necessary to provide a back pressure valve, and further, a flow path for installing the back pressure valve is required. An object of the present invention is to solve the above problem by discharging accumulated water by a simple method without using a large-scale structure.

The present invention has been made to solve the above problems, and can be realized as the following embodiments.
A first embodiment according to the present invention is a fuel cell stack in which a plurality of cells each including a joined body including an electrolyte membrane and a separator sandwiching the joined body are stacked. The fuel cell stack is formed by the plurality of cells, the fuel gas supplied to the fuel cell stack, a fuel gas supply flow path for flowing into the assembly, and formed by the plurality of cells, A fuel gas discharge passage for discharging fuel gas flowing out of the assembly to the outside of the fuel cell stack; a first opening end disposed in the fuel gas discharge passage; And a second open end located downstream of the end of the fuel gas discharge flow path. The pipe is arranged such that the first open end and the second open end are accommodated in the fuel gas discharge flow path in the fuel cell stack in a state where the first open end and the second open end are opened without being connected to other pipes. is set up. According to this embodiment, the water remaining in the fuel gas discharge channel can be discharged by a simple method of adding a pipe. The retained water can be discharged by the above-mentioned pipe because the pressure at the first open end is higher than the pressure at the second open end. Such a pressure difference occurs because the fuel gas flows through the fuel gas discharge flow path, causing a pressure loss.

  According to one aspect of the present invention, there is provided a fuel cell stack in which a plurality of cells each including a joined body including an electrolyte membrane and a separator sandwiching the joined body are stacked. The fuel cell stack is formed by the plurality of cells, and a fuel gas supply flow path for allowing the fuel gas supplied to the fuel cell stack to flow into the assembly is formed by the plurality of cells; A fuel gas discharge passage for discharging fuel gas flowing out of the assembly to the outside of the fuel cell stack; a first opening end disposed in the fuel gas discharge passage, and the first opening; A pipe having a second open end located on the downstream side of the fuel gas discharge flow path from the end. According to this embodiment, the water remaining in the fuel gas discharge channel can be discharged by a simple method of adding a pipe. The retained water can be discharged by the above-mentioned pipe because the pressure at the first open end is higher than the pressure at the second open end. Such a pressure difference occurs because the fuel gas flows through the fuel gas discharge flow path, causing a pressure loss.

  In the above aspect, a plate for sealing an upstream end of the fuel gas discharge passage may be provided; the first open end may be at least partially in contact with the plate. According to this aspect, the retained water is more easily discharged.

  In the above embodiment, the first opening end may have a notch. According to this aspect, the first opening end is less likely to be blocked by another member, impurities, or the like.

  In the above aspect, the pipe has a configuration in which a resin flow path member and a metal flow path member are connected, and the metal flow path member is more than the resin flow path member. It may be located on the upstream side of the fuel gas discharge channel. According to this aspect, the position of the pipe is stabilized by the weight of the metal flow path member.

  In the above aspect, the second opening end may be located on the downstream side of the fuel gas discharge channel from the cell located on the most downstream side of the fuel gas exhaust channel. According to this aspect, by disposing the second opening end as described above, the pressure loss is further increased, and as a result, the retained water is more easily discharged.

  In the above aspect, a main flow path through which the gas flowing through the fuel gas discharge flow path passes, and a sub flow path that joins the main flow path are provided, and a merging pipe is provided in the fuel gas discharge flow path; The flow path area of the main flow path is smaller than the flow path area of the fuel gas discharge flow path; the sub flow path is connected to the second open end at an open end communicating with a portion joining the main flow path. May be done. According to this aspect, when the gas flowing through the fuel gas discharge flow path flows into the main flow path, the pressure decreases. Since the sub flow path communicates with a portion where it merges with the main flow channel, and the opening end of the sub flow channel is connected to the second opening end, the merging portion communicates with the first opening end. For this reason, the pressure difference between the first opening end and the junction is increased by the pressure drop. As a result, the accumulated water is more easily discharged.

  The present invention can be realized in various forms other than the above. For example, it can be realized as a method of discharging accumulated water.

FIG. 2 is a schematic perspective view showing the configuration of a fuel cell stack. Sectional drawing of a fuel cell stack. Sectional drawing which expanded the pipe vicinity. The figure which shows the range from an insulating plate to a terminal plate about az direction. FIG. 4 is a cross-sectional view showing a state in which water stays on the rear end side of the fuel gas discharge channel. Sectional drawing which shows a mode that a stagnant water is discharged. The figure explaining the modification 1. The figure explaining the modification 2. The figure explaining the modification 3. The figure explaining the modification 3.

  FIG. 1 is a schematic perspective view showing the configuration of the fuel cell stack 10. The fuel cell stack 10 is mounted on an automobile and generates electric power to supply power to a driving motor and the like.

  The fuel cell stack 10 has a structure in which a stack of the fuel cells 100 is sandwiched between a pair of end plates 170F and 170E. The stacked body of the fuel cells 100 is formed by stacking a plurality of fuel cells 100 in the z direction (stacking direction).

  The fuel cell stack 10 has a terminal plate 160F with an insulating plate 165F interposed between an end plate 170F on one end side and the fuel cell 100. Hereinafter, one end side of the fuel cell stack 10 on which the end plate 170F is disposed is referred to as a front end side for convenience, and the other end side on the back side in the drawing is referred to as a rear end side.

  Similarly, the fuel cell stack 10 has a rear terminal plate 160E between the rear end plate 170E and the fuel cell 100 with a rear insulating plate 165E interposed therebetween. Each of the fuel cell 100, the terminal plates 160F and 160E, the insulating plates 165F and 165E, and the end plates 170F and 170E has a plate structure having a substantially rectangular outer shape. The sides are arranged along the y direction.

  The end plate 170F, the insulating plate 165F, and the terminal plate 160F on the front end side include a fuel gas supply hole 102IN, a fuel gas discharge hole 102OT, an oxidizing gas supply hole 104IN, an oxidizing gas discharge hole 104OT, and a cooling water supply hole 106IN. And a cooling water discharge hole 106OT.

  The oxidizing gas supply hole 104IN is arranged along the x direction (long side direction) at the outer edge of the lower end of the front end plate 170F, and the oxidizing gas discharge hole 104OT is arranged along the x direction at the outer edge at the upper end. It is arranged. The fuel gas supply hole 102IN is disposed at the upper end in the y-direction (short side direction) of the right edge of the front end plate 170F, and the fuel gas discharge hole 102OT is located in the y-direction of the left edge. It is located at the lower end. The cooling water supply hole 106IN is disposed below the fuel gas supply hole 102IN along the y direction, and the cooling water discharge hole 106OT is disposed above the fuel gas discharge hole 102OT along the y direction. . Each of the above-described supply and discharge holes is divided into a plurality of supply and discharge holes in the fuel cell 100.

  The front end terminal plate 160F and the rear end terminal plate 160E are current collecting plates for the generated power of each fuel cell 100, and output the power collected from the current collecting terminal 161 to the outside. The terminal plates on the front end side and the rear end side differ in the presence or absence of supply / discharge holes, and other configurations are almost the same.

  The virtual plane V shown in FIG. 1 is shown to show a cross section of FIG. 4 described later. A broken line shown on the outer surface of the fuel cell stack 10 indicates an intersection with the virtual plane V.

  FIG. 2 is a cross-sectional view of the fuel cell stack 10, showing a surface where the anode-side separator 120 is exposed as a boundary between the fuel cells 100.

  The fuel cell 100 includes an anode-side separator 120, a cathode-side separator (not shown), and an adhesive seal (not shown). The adhesive seal holds a MEGA (Membrane Electrode & Gas Diffusion Layer Assembly) and seals the outer periphery of the MEGA.

  The fuel cell 100 holds the MEGA by sandwiching the adhesive seal holding the MEGA between the anode-side separator 120 and the cathode-side separator.

  MEGA is an assembly formed by sandwiching a membrane electrode assembly (MEA: Membrane Electrode Assembly) with a gas diffusion layer (Gas Diffusion Layer / GDL). The MEA has a configuration in which a pair of catalyst electrode layers are formed on both surfaces of an electrolyte membrane. Note that the MEGA may be referred to as an MEA.

  The anode-side separator 120 and the cathode-side separator are made of a member having gas impermeability and electron conductivity. For example, the anode-side separator 120 is formed of a carbon member made of dense carbon or the like which is made gas-impermeable by compressing carbon particles, or a metal member made of press-formed stainless steel or titanium. In this embodiment, the anode-side separator 120 was manufactured by press-molding stainless steel.

  The anode-side separator 120 includes a plurality of grooved fuel gas flow paths on the surface on the MEGA side, and includes a plurality of grooved cooling water flow paths on the opposite surface. Both flow paths are alternately arranged on the front and back surfaces of the separator.

  The anode-side separator 120 includes fuel gas supply holes 102IN and fuel gas discharge holes 102OT, a plurality of oxidizing gas supply holes 104IN and oxidizing gas discharge holes 104OT, and a plurality of cooling water supply holes 106IN as supply / discharge holes constituting a manifold. And a cooling water discharge hole 106OT. Similarly, the cathode-side separator has a similar configuration.

  By stacking the fuel cells 100, a plurality of fuel gas supply holes 102IN are connected. A flow path formed by connecting a plurality of fuel gas supply holes 102IN is referred to as a fuel gas supply flow path 80. The fuel gas supply channel 80 functions as a channel for guiding the fuel gas (hydrogen) supplied to the fuel cell stack 10 to each MEGA. The fuel gas guided to each MEGA flows into a fuel gas flow path provided in the anode-side separator 120 included in each MEGA.

  Similarly, a flow path formed by connecting a plurality of fuel gas discharge holes 102OT is referred to as a fuel gas discharge flow path 90. The fuel gas discharge passage 90 functions as a passage for discharging the fuel gas flowing out of the fuel gas passage provided in the anode-side separator 120 to the outside of the fuel cell stack 10. As shown in FIG. 2, a pipe 200 is provided in the fuel gas discharge channel 90.

  FIG. 3 is an enlarged sectional view of the vicinity of the pipe 200. The pipe 200 is held in the fuel gas discharge channel 90 by a hook 180. As shown in FIG. 3, the hook portion 180 has a hook-like cross-sectional shape, and restricts the movement of the tube 200 in the xy plane direction. FIG. 1 omits illustration of the hook 180.

  As shown in FIG. 3, the flow passage area of the pipe 200 is smaller than the flow passage area of the fuel gas discharge flow passage 90. As shown in FIG. 3, the pipe 200 is arranged such that the outer peripheral surface is in contact with the bottom surface of the fuel gas discharge channel 90.

  FIG. 4 shows the AA cross section shown in FIGS. 1 and 3. FIG. 4 shows a range from the insulating plate 165F to the terminal plate 160E in the z direction. FIG. 4 does not show the boundaries between the fuel cells 100 for convenience of illustration. Reference numeral 100 in FIG. 4 indicates a stacked body including a plurality of fuel cells 100.

  The flow direction in the fuel gas discharge channel 90 is a positive direction in the z direction, that is, a direction from the rear end to the front end. The upstream end of the fuel gas discharge channel 90 is sealed by a terminal plate 160E.

  The tube 200 is a hollow member formed of resin and having a front end side open end 210F and a rear end side open end 210E. As shown in FIG. 4, the pipe 200 has a notch in a part of the rear end side open end 210 </ b> E. The end face formed by this notch is a part of the rear end side open end 210E.

  The tube 200 is arranged such that the notch is located below the center axis in the y direction, and that a part of the rear end side opening end 210E is in contact with the terminal plate 160E. The part in contact with the terminal plate 160E is a part that is not notched.

  Tube 200 has a length in the z-direction approximately equal to the distance from terminal plate 160F to terminal plate 160E. For this reason, the front end side opening end 210F is located near the terminal plate 160F.

  FIG. 5 is a cross-sectional view showing a state in which water stays at the rear end side of the fuel gas discharge passage 90. The causes of the generation of such stagnant water include stopping supply and discharge of the fuel gas and tilting of the fuel cell stack 10 as shown in FIG. The reason why the fuel cell stack 10 tilts is that an automobile equipped with the fuel cell stack 10 tilts. When tilted in this manner, the retained water enters the flow path of the pipe 200 through the rear end opening end 210E.

  FIG. 6 is a cross-sectional view showing a state in which accumulated water is discharged. The discharge of the stagnant water is realized by the tube 200 functioning as a straw, as shown in FIG. That is, due to the pressure difference between the vicinity of the rear end opening end 210E and the vicinity of the front end opening end 210F, the retained water flows in the pipe 200 from the rear end opening end 210E toward the front end opening end 210F against the gravity. It flows.

  The pressure difference is caused by the pressure loss caused by the flow of the fuel gas. In FIG. 6, the pressure near the rear end opening end 210E is shown as pressure Pe, and the pressure near the front end opening end 210F is shown as pressure Pf. (Pressure Pe-Pressure Pf) corresponds to the pressure difference.

  According to the above-described embodiment, the stagnant water is efficiently discharged by the simple method of installing the pipe 200 in the fuel gas discharge passage 90 even under severe conditions in which the rear end is inclined downward. it can. In particular, the rear open end 210E is arranged so as to be in contact with the terminal plate 160F, and the rear open end 210E is provided with a cutout. Water can be discharged efficiently.

  FIG. 7 is a diagram illustrating the first modification. The fuel cell stack 10 of the first modification does not include the hook portion 180 but includes a tube 200a instead of the tube 200. The pipe 200a includes a main flow path member 270 and a weight 280.

  The main flow path member 270 is formed of resin, similarly to the pipe 200 of the embodiment. The weight 280 is made of metal (for example, iron), and is heavier than the main flow path member 270. The weight 280 is a ring-shaped member, and a region surrounded by the inner peripheral surface in the ring shape functions as a flow path. The weight 280 is connected to the main flow path member 270 so that the flow path formed by the inner peripheral surface and the flow path in the main flow path member 270 are connected. The arrangement of the tube 200b is stabilized by the weight of the weight 280.

  The weight 280 is disposed so as to contact the terminal plate 160 </ b> E on the side opposite to the connection portion with the main flow path member 270. That is, the tube 200a is arranged so as to contact the terminal plate 160E.

  The weight 280 includes a plurality of notches 288. The notch 288 is formed so as to cut out a contact surface with the terminal plate 160E. The stagnant water can flow into the weight 280 from the fuel gas discharge channel 90 through the notch 288. The stagnant water flowing into the weight 280 passes through the main flow path member 270 and is discharged to the outside as in the embodiment.

  According to the first modification, the position of the tube 200a can be stabilized by the weight of the weight 280 without the hook portion 180.

  FIG. 8 is a diagram illustrating a second modification. The fuel cell stack 10 of Modification 2 includes a tube 200b instead of the tube 200 in the embodiment. Further, a terminal plate 160Fb is provided instead of the terminal plate 160F, and an insulating plate 165Fb is provided instead of the insulating plate 165F.

  As in the embodiment, the tube 200b has a cutout in a part of the rear end side open end 210E, and is arranged such that a part of the rear end side open end 210E contacts the terminal plate 160E.

  Tube 200b is longer than tube 200. Therefore, as shown in FIG. 8, the front open end 210F of the tube 200b is located closer to the front end (positive side in the z direction) than the terminal plate 160Fb. That is, the front end side opening end 210F of the tube 200b is located further downstream than the fuel cell 100 located at the most downstream side of the fuel gas discharge channel 90.

  The opening shapes of the terminal plate 160Fb and the insulating plate 165Fb are changed from the embodiment. This is to allow the front end side open end 210F to be located on the front end side of the terminal plate 160Fb.

  According to the second modification, the pressure difference between the rear-side opening end 210E and the front-side opening end 210F is increased by arranging the front-side opening end 210F further downstream than in the embodiment. Therefore, the accumulated water is further efficiently discharged.

  9 and 10 are diagrams illustrating a third modification. FIG. 9 is a view of the same cross section as FIG. FIG. 10 shows a BB cross section shown in FIG.

  The fuel cell stack 10 of Modification 3 includes a tube 200c instead of the tube 200, and further includes a junction tube 300. In the fuel cell stack 10 of Modification 3, the terminal plate 160Fc is used instead of the terminal plate 160F, the insulating plate 165Fc is used instead of the insulating plate 165F, and the end plate 170Fc is used instead of the end plate 170F so that the junction tube 300 can be installed. Is provided.

  As in the embodiment, the tube 200c has a notch in a part of the rear end opening end 210E, and is arranged such that a part of the rear end opening end 210E contacts the terminal plate 160E.

  The merging pipe 300 has a main flow channel 310 and a sub flow channel 320 provided therein. The main flow path 310 is a flow path that connects the fuel gas discharge flow path 90 and the outside of the fuel cell stack 10. The sub flow path 320 is a flow path for joining the fluid flowing out of the pipe 200c to the main flow path 310. A portion where the main flow channel 310 and the sub flow channel 320 are connected is referred to as a connection portion 322.

  As shown in FIG. 9, the main passage 310 has a smaller passage area than the fuel gas discharge passage 90. For this reason, the gas flowing from the fuel gas discharge channel 90 into the main channel 310 has a higher flow velocity and lower pressure. For this reason, the pressure difference between the rear end side opening end 210E and the connecting portion 322 is larger than the pressure difference in the embodiment. As a result, the accumulated water is more efficiently discharged.

  The present invention is not limited to the embodiments, examples, and modifications of the present specification, and can be realized by various configurations without departing from the gist thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each of the forms described in the Summary of the Invention section are for solving some or all of the problems described above, or In order to achieve some or all of the above-described effects, replacement and combination can be appropriately performed. If the technical features are not described as essential in this specification, they can be deleted as appropriate. For example, the following are exemplified.

  A configuration including a weight as in the first modification, and a configuration in which the rear open end is disposed downstream of the fuel cell located at the most downstream side of the fuel gas discharge channel as in the second modification. May be combined.

  A configuration having a weight as in Modification 1 and a configuration using a merging pipe as in Modification 3 may be combined.

Notches need not be provided in the tube. In this case, the rear end side open end does not have to be in contact with the terminal plate.
The entire rear end side open end may be brought into contact with the terminal plate. In this case, a through hole may be provided in the terminal plate. The through-hole forms a curved flow path connecting the flow path in the pipe and the fuel gas discharge flow path.

  The junction pipe may be arranged in the fuel gas discharge channel 90. Even with this arrangement, if the flow passage area of the main flow passage is smaller than the flow passage area of the fuel gas discharge flow passage 90, the same effect as that of the third modification is obtained by the main flow passage functioning as a throttle. be able to.

  A flow path member having only a main flow path may be used instead of the junction pipe. In this case, by arranging the front open end of the pipe in the main flow path, the same effect as that of the third modification can be obtained.

  The tubes need not be arranged straight along the stacking direction, but may be arranged diagonally or may be bent in the middle.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 80 ... Fuel gas supply flow path 90 ... Fuel gas discharge flow path 100 ... Fuel cell cell 102IN ... Fuel gas supply hole 102OT ... Fuel gas discharge hole 103 ... Outer edge 104IN ... Oxidation gas supply hole 104OT ... Oxidation gas Discharge hole 106IN Cooling water supply hole 106OT Cooling water discharge hole 120 Anode side separator 160E Terminal plate 160F Terminal plate 160Fb Terminal plate 160Fc Terminal plate 161 Current collecting terminal 165E Insulating plate 165F Insulating plate 165Fb Insulating plate 165Fc ... Insulating plate 170E ... End plate 170F ... End plate 170Fc ... End plate 180 ... Hook 200 ... Tube 200a ... Tube 200b ... Tube 200c ... Tube 210E ... Rear end opening end (first opening) )
210F: front end side open end (second open end)
270: Main flow path member 300: Confluence pipe 310: Main flow path 320: Sub flow path 322: Connection

Claims (6)

A fuel cell stack in which a plurality of cells each including a joined body including an electrolyte membrane and a separator sandwiching the joined body are stacked.
A fuel gas supply channel formed by the plurality of cells and supplied to the fuel cell stack, for flowing the fuel gas into the assembly.
A fuel gas discharge channel formed by the plurality of cells and flowing out of the fuel cell from the assembly, for discharging the fuel gas to the outside of the fuel cell stack,
A pipe disposed in the fuel gas discharge flow path, the pipe having a first open end, and a second open end located downstream of the fuel gas discharge flow path with respect to the first open end;
With
The pipe is arranged such that the first open end and the second open end are accommodated in the fuel gas discharge flow path in the fuel cell stack in a state where the first open end and the second open end are opened without being connected to other pipes. The installed fuel cell stack.   The pipe is held in the fuel gas discharge channel by a hook portion protruding from a wall surface of the fuel gas discharge channel, and the hook portions allow movement of the plurality of cells in a long side direction and a short side direction. Restricted
  The fuel cell stack according to claim 1. A plate for sealing an upstream end of the fuel gas discharge channel,
It said first open end, a fuel cell stack according to claim 1 or claim 2 in contact with the plate at least in part. The fuel cell stack according to any one of claims 1 to 3 , wherein the first open end has a notch. The pipe has a configuration in which a resin flow path member and a metal flow path member are connected, and the metal flow path member has a higher fuel gas discharge flow rate than the resin flow path member. The fuel cell stack according to any one of claims 1 to 4 , which is located on an upstream side of a road. It said second open end, the fuel than the cell most located downstream of the gas discharge channel, any one of claims 1 located downstream of the fuel gas discharge channel to claim 5 Item 8. The fuel cell stack according to Item 1.

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