JP6059552B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack having a fuel cell in which an electrolyte membrane / electrode structure provided with electrodes on both sides of an electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure in which an anode electrode is disposed on one side of an electrolyte membrane made of a polymer ion exchange membrane and a cathode electrode is disposed on the other surface side ( MEA) is provided with a power generation cell sandwiched between separators. A fuel cell is usually incorporated in a fuel cell vehicle as an in-vehicle fuel cell stack, for example, by stacking a predetermined number of power generation cells.

  In the above fuel cell, a fuel gas channel for flowing fuel gas to the anode electrode and an oxidant gas channel for flowing oxidant gas to the cathode electrode are provided in the plane of the separator. Furthermore, between the separators, a cooling medium flow path for flowing the cooling medium is provided along the surface direction of the separator.

  The end plate disposed at one end in the stacking direction includes, for example, a fuel gas supply passage for supplying fuel gas to the fuel gas passage, and a fuel gas discharge passage for discharging used fuel gas from the fuel gas passage. Fluid communication holes such as an oxidant gas supply communication hole for supplying oxidant gas to the oxidant gas flow path and an oxidant gas discharge communication hole for discharging used oxidant gas from the oxidant gas flow path are formed. May have been.

  In this internal manifold type fuel cell, a piping structure is employed to connect each communication hole and external equipment. As this type of technology, for example, a pipe structure of a fuel cell stack disclosed in Patent Document 1 is known.

  As shown in FIG. 9, the piping structure of Patent Document 1 has a fuel cell stack 2 that generates electricity by reacting a fuel gas and an oxidant gas by an electrochemical reaction, and supplies the oxidant gas to the fuel cell stack 2. From the oxidant gas inlet pipe 3, the cooling water inlet pipe 4 for supplying cooling water to the fuel cell stack 2, the fuel gas outlet pipe 5 for discharging fuel gas from the fuel cell stack 2, and the fuel cell stack 2 A cooling water outlet pipe 6 for discharging cooling water, a fuel gas inlet pipe 7 for supplying fuel gas to the fuel cell stack 2, an oxidant gas outlet pipe 8 for discharging oxidant gas from the fuel cell stack 2, And a fuel cell manifold 9 for connecting each pipe such as the oxidant gas inlet pipe 3 to the fuel cell stack 2.

JP 2006-228632 A

  By the way, in said piping structure, each piping is bent at the angle of about 90 degree | times, and is comprised by L shape. For this reason, there is a problem that a large pressure loss is likely to occur inside the pipe, and the smooth circulation of the fluid is not performed.

  The present invention solves this type of problem, and provides a fuel cell stack capable of suppressing pressure loss in piping as much as possible and allowing fluid to flow smoothly and uniformly. With the goal.

  The present invention has a fuel cell in which an electrolyte membrane / electrode structure provided with electrodes on both sides of an electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked and end plates are arranged at both ends in the stacking direction. And at least one of the end plates communicates with the fluid communication hole and external piping in the stacking direction of the fuel cell. The present invention relates to a fuel cell stack to which a connecting pipe is connected.

In this fuel cell stack, the connecting pipe is provided with a fluid inlet connected to the external pipe, a fluid outlet connected to the fluid communication hole, and a curved line between the fluid inlet and the fluid outlet. It has the piping intermediate part set to an opening cross-sectional area larger than an opening cross-sectional area. A portion pipe intermediate portion from the opening range of the front view of the fluid outlet, which have a bulging portion that bulges to the side opposite to the fluid inlet, constituting the inside of the curved shape of the pipe intermediate portion, said Projecting toward the opposite side of the fluid inlet and projecting toward the bulging portion .

In this fuel cell stack, the fluid flow direction at the fluid inlet is preferably set to a direction orthogonal to the fluid flow direction of the fluid communication hole. The pipe intermediate part is a part constituting the curved outer side of the pipe intermediate part, and is a bulge region that bulges to a part closer to the fluid inlet than the bulge and to the opposite side of the fluid outlet. It is preferable to have.

  According to the present invention, the pipe intermediate portion of the connection pipe is set to have an opening cross-sectional area larger than the opening cross-sectional area of the fluid outlet, and is curved, and from the opening range in front view of the fluid outlet, Has a bulging portion that bulges on the opposite side. Accordingly, the pressure loss of the fluid is suppressed as much as possible in the connecting pipe, so that the fluid can be circulated smoothly and uniformly.

  In addition, the connecting pipe is curved on the way. As a result, the layout of the piping structure can be improved and the fuel cell can be made compact in the stacking direction.

1 is a schematic perspective view of a fuel cell stack according to an embodiment of the present invention. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. It is a perspective explanatory view showing the inside of oxidant gas supply connection piping which constitutes the fuel cell stack. It is a section explanatory view of the above-mentioned oxidizing gas supply connection piping. It is a figure which shows the speed contour in the oxidizing gas supply connection piping of a comparative example. It is a figure which shows the speed contour in the oxidizing gas supply connection piping of this embodiment. It is a figure which shows the pressure contour line of the oxidizing agent gas exit vicinity of the said comparative example. It is a figure which shows the pressure contour line of the oxidizing gas outlet vicinity of this embodiment. It is a perspective explanatory view of a piping structure of patent documents 1.

  As shown in FIG. 1, the fuel cell stack 10 according to the embodiment of the present invention is mounted on, for example, a fuel cell electric vehicle (not shown). In the fuel cell stack 10, a plurality of fuel cells 12 are stacked in the horizontal direction (arrow B direction) with the electrode surface in an upright posture. Note that the fuel cell stack 10 may be configured by stacking a plurality of fuel cells 12 in the direction of gravity.

  At one end in the stacking direction of the fuel cell 12, a first terminal plate 14a, a first insulating plate 16a, and a first end plate 18a are sequentially disposed outward. At the other end of the fuel cell 12 in the stacking direction, a second terminal plate 14b, a second insulating plate 16b, and a second end plate 18b are sequentially disposed outward.

  A first power output terminal 20a connected to the first terminal plate 14a extends outward from the center portion of the horizontally long first end plate 18a. A second power output terminal 20b connected to the second terminal plate 14b extends outward from the center portion of the horizontally long second end plate 18b.

  Between the sides of the first end plate 18a and the second end plate 18b, both ends of the connecting bar 22 are fixed by screws 24, and a plurality of stacked fuel cells 12 are subjected to a tightening load in the stacking direction (arrow B direction). Give.

  As shown in FIG. 2, the fuel cell 12 includes an electrolyte membrane / electrode structure 26, and a cathode side separator 28 and an anode side separator 30 that sandwich the electrolyte membrane / electrode structure 26.

  The cathode-side separator 28 and the anode-side separator 30 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate whose surface is subjected to anticorrosion treatment. The cathode-side separator 28 and the anode-side separator 30 have a rectangular planar shape, and are formed into a concavo-convex shape by pressing a metal thin plate into a wave shape. For example, a carbon separator may be used as the cathode side separator 28 and the anode side separator 30 instead of the metal separator.

  The cathode side separator 28 and the anode side separator 30 have a horizontally long shape, and are configured such that the long side extends in the horizontal direction (arrow A direction) and the short side extends in the gravity direction (arrow C direction). The In addition, you may comprise so that a short side may extend in a horizontal direction and a long side may extend in a gravitational direction.

  A rectangular shape (or a triangular shape) such as a rectangular shape that communicates with each other in the arrow B direction and supplies an oxidant gas, for example, an oxygen-containing gas, to one edge of the long side direction (arrow A direction) of the fuel cell 12 The oxidant gas supply communication hole 32a and a fuel gas supply communication hole 34a having a rectangular shape (or a triangular shape) such as a rectangle for supplying a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge in the long side direction of the fuel cell 12 communicates with each other in the direction of arrow B, and has a rectangular (or triangular) fuel gas discharge communication hole 34b such as a rectangle for discharging the fuel gas, and an oxidant. A rectangular (or triangular) oxidant gas discharge communication hole 32b for discharging gas is provided.

  Both ends of the fuel cell 12 in the short side direction (arrow C direction) (one side in the horizontal direction), that is, on the side of the oxidant gas supply communication hole 32a and the fuel gas supply communication hole 34a are in the direction of arrow B. Two cooling medium supply communication holes 36a having a rectangular shape (or a triangular shape) such as a rectangle for supplying the cooling medium are provided vertically on opposite sides.

  The fuel cell 12 communicates with each other in the direction of arrow B on the other side (the other end in the horizontal direction) of both ends in the short side direction, that is, on the fuel gas discharge communication hole 34b and the oxidant gas discharge communication hole 32b side. In addition, two rectangular (or triangular) cooling medium discharge communication holes 36b such as a rectangle for discharging the cooling medium are provided vertically on opposite sides.

  The electrolyte membrane / electrode structure 26 includes, for example, a solid polymer electrolyte membrane 38 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode electrode 40 and an anode electrode 42 sandwiching the solid polymer electrolyte membrane 38. Prepare.

  The cathode electrode 40 and the anode electrode 42 are formed by uniformly applying a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof to the surface of the gas diffusion layer. And an electrode catalyst layer (not shown) to be formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 38.

  An oxidant gas flow path 44 that connects the oxidant gas supply communication hole 32a and the oxidant gas discharge communication hole 32b is formed on the surface 28a of the cathode separator 28 facing the electrolyte membrane / electrode structure 26. The oxidant gas channel 44 is formed by a plurality of wavy channel grooves (or linear channel grooves) extending in the direction of arrow A.

  A fuel gas flow path 46 that connects the fuel gas supply communication hole 34a and the fuel gas discharge communication hole 34b is formed on the surface 30a of the anode separator 30 facing the electrolyte membrane / electrode structure 26. The fuel gas channel 46 is formed by a plurality of wave-like channel grooves (or linear channel grooves) extending in the direction of arrow A.

  Between the surface 30b of the anode-side separator 30 and the surface 28b of the adjacent cathode-side separator 28, there is a cooling medium channel 48 communicating with the cooling medium supply communication holes 36a, 36a and the cooling medium discharge communication holes 36b, 36b. It is formed. The cooling medium flow path 48 extends in the horizontal direction and allows the cooling medium to flow over the electrode range of the electrolyte membrane / electrode structure 26.

  A first seal member 50 is integrally formed on the surfaces 28 a and 28 b of the cathode side separator 28 around the outer peripheral edge of the cathode side separator 28. A second seal member 52 is integrally formed on the surfaces 30 a and 30 b of the anode separator 30 so as to go around the outer peripheral edge of the anode separator 30.

  As the first seal member 50 and the second seal member 52, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushion material Alternatively, an elastic seal member such as a packing material is used.

  As shown in FIG. 1, the oxidant gas communicating with the oxidant gas supply communication hole 32a, the oxidant gas discharge communication hole 32b, the fuel gas supply communication hole 34a, and the fuel gas discharge communication hole 34b is connected to the first end plate 18a. A supply connection pipe 54a, an oxidant gas discharge connection pipe 54b, a fuel gas supply connection pipe 56a, and a fuel gas discharge connection pipe 56b are attached.

  The oxidant gas supply connecting pipe 54 a has a plate-like attachment portion 58, and the plate-like attachment portion 58 is disposed corresponding to the oxidant gas supply communication hole 32 a of the first end plate 18 a through the seal 60. . The plate-like attachment portion 58 is fixed to the first end plate 18a by screws 62. A main body portion 64 is integrally formed from the plate-like attachment portion 58, and a circular oxidant gas inlet (fluid inlet) 66 is provided at the tip of the main body portion 64.

  As shown in FIGS. 1 and 3, a rectangular (or triangular) oxidant gas outlet (fluid outlet) 68 that communicates with the oxidant gas supply communication hole 32 a is formed in the plate-like attachment portion 58. The oxidant gas supply connection pipe 54a is located between the oxidant gas inlet 66 and the oxidant gas outlet 68, and has a pipe intermediate part 70 that is curved with an angle of about 90 °. As shown in FIG. 4, the oxidant gas flow direction of the oxidant gas inlet 66 is set to a direction orthogonal to the oxidant gas flow direction of the oxidant gas supply communication hole 32a.

  As shown in FIGS. 3 and 4, the opening cross-sectional area W <b> 1 of the pipe intermediate portion 70 is set to a value larger than the opening cross-sectional area W <b> 2 of the oxidant gas inlet 66 and the open cross-sectional area W <b> 3 of the oxidant gas outlet 68. (W1> W2, W1> W3). As shown in FIG. 4, the pipe intermediate portion 70 has a bulging portion 72 that bulges to the opposite side of the oxidant gas inlet 66 from the opening range of the oxidant gas outlet 68 in front view.

  The inner wall surface 54ai of the oxidant gas supply connecting pipe 54a is formed smoothly from the oxidant gas inlet 66 to the pipe intermediate part 70 and from the oxidant gas outlet 68 to the pipe intermediate part 70, respectively. The inner wall surface 54ai of the oxidant gas supply connecting pipe 54a is constituted by only an outward curved surface that is smoothly continuous as a whole and curved outward in the pipe length direction. That is, the inner wall surface 54ai of the oxidant gas supply connecting pipe 54a is not provided with a portion that is curved or bent (reduced portion) inward.

  The oxidant gas discharge connection pipe 54b is configured in the same manner as the oxidant gas supply connection pipe 54a described above, and the same components are denoted by the same reference numerals and detailed description thereof is omitted. To do. The oxidant gas supply connection pipe 54a and the oxidant gas discharge connection pipe 54b are connected to an external device (not shown) such as a humidifier through an external pipe (not shown), for example.

  As shown in FIG. 1, the fuel gas supply connection pipe 56a and the fuel gas discharge connection pipe 56b are configured in the same manner as the oxidant gas supply connection pipe 54a, and the same reference numerals are used for the same components. A detailed description is omitted. The fuel gas supply connection pipe 56a and the fuel gas discharge connection pipe 56b are connected to an external device (not shown) via an external pipe (not shown).

  The second end plate 18b has a cooling medium supply connection pipe (not shown) that communicates integrally with the upper and lower cooling medium supply communication holes 36a, 36a and a cooling that communicates integrally with the upper and lower cooling medium discharge communication holes 36b, 36b. A medium discharge connecting pipe (not shown) is attached.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied from the oxidant gas supply connection pipe 54a of the first end plate 18a to the oxidant gas supply communication hole 32a. A fuel gas such as a hydrogen-containing gas is supplied from the fuel gas supply connection pipe 56a of the first end plate 18a to the fuel gas supply communication hole 34a.

  On the other hand, a coolant such as pure water, ethylene glycol, or oil is supplied from the coolant supply connection pipe of the second end plate 18b to the pair of coolant supply passages 36a.

  As a result, as shown in FIG. 2, the oxidant gas is introduced into the oxidant gas flow path 44 of the cathode-side separator 28 from the oxidant gas supply communication hole 32 a. The oxidant gas moves in the direction of arrow A along the oxidant gas flow path 44 and is supplied to the cathode electrode 40 of the electrolyte membrane / electrode structure 26.

  On the other hand, the fuel gas is supplied from the fuel gas supply communication hole 34 a to the fuel gas flow path 46 of the anode side separator 30. The fuel gas moves in the direction of arrow A along the fuel gas flow path 46 and is supplied to the anode electrode 42 of the electrolyte membrane / electrode structure 26.

  Therefore, in the electrolyte membrane / electrode structure 26, the oxidizing gas supplied to the cathode electrode 40 and the fuel gas supplied to the anode electrode 42 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Done.

  Next, the oxidant gas supplied to and consumed by the cathode electrode 40 of the electrolyte membrane / electrode structure 26 circulates in the direction of arrow B along the oxidant gas discharge communication hole 32b, and from the oxidant gas discharge connection pipe 54b. It is discharged (see FIG. 1). On the other hand, the fuel gas supplied to and consumed by the anode electrode 42 of the electrolyte membrane / electrode structure 26 flows in the direction of arrow B along the fuel gas discharge communication hole 34b and is discharged from the fuel gas discharge connection pipe 56b. .

  The cooling medium supplied to the pair of cooling medium supply communication holes 36 a is introduced into the cooling medium flow path 48 between the cathode side separator 28 and the anode side separator 30. The cooling medium once flows in the direction of arrow C and then moves in the direction of arrow A to cool the electrolyte membrane / electrode structure 26. The cooling medium moves outward in the direction of arrow C, then flows in the direction of arrow B along the pair of cooling medium discharge communication holes 36b, and is discharged from the cooling medium discharge connecting pipe.

  In this case, in this embodiment, as shown in FIGS. 3 and 4, the oxidant gas supply connection pipe 54 a has an opening cross-sectional area W1 of the pipe intermediate portion 70 larger than an opening cross-sectional area W3 of the oxidant gas outlet 68. A large value is set (W1> W3). Further, as shown in FIG. 4, the pipe intermediate portion 70 has a bulging portion 72 that bulges from the opening range of the oxidant gas outlet 68 in a front view to the side opposite to the oxidant gas inlet 66. .

  For this reason, the pressure loss of the oxidant gas is suppressed as much as possible in the oxidant gas supply connecting pipe 54a. Therefore, the oxidant gas supply communication hole 32a has an effect that the oxidant gas can be smoothly and uniformly circulated from the external pipe (not shown) through the oxidant gas supply connection pipe 54a. .

  Moreover, the oxidant gas supply connecting pipe 54a is curved at an angle of approximately 90 degrees along the way. As a result, the layout of the piping structure can be improved and the fuel cell stack 10 can be compactly configured in the stacking direction. The same effect can be obtained with the fuel gas supply connecting pipe 56a.

  Here, as shown in FIG. 5, an oxidant gas supply connecting pipe 54comp. Was prepared as a comparative example. The oxidant gas supply connecting pipe 54comp. Has an oxidant gas inlet 66comp., An oxidant gas outlet 68comp., And a pipe intermediate part 70comp., And the opening cross-sectional area of the pipe intermediate part 70comp. It has the same value as the opening cross-sectional area of 68comp. The pipe intermediate part 70comp. Is bent at an angle of about 90 degrees and does not have the bulging part 72 of the present embodiment.

  An experiment was performed to detect the flow velocity and pressure in the pipe using the oxidant gas supply connection pipe 54comp. As a comparative example and the oxidant gas supply connection pipe 54a according to the present embodiment. As a result, in the oxidant gas supply connecting pipe 54comp., As shown by the speed contour line in FIG. 5, the speed in the pipe largely fluctuates partly, and in particular, in the vicinity of the oxidant gas outlet 68comp. 70comp.s was formed. For this reason, there is a problem that the oxidant gas cannot be uniformly supplied to the oxidant gas supply communication hole 32a.

  On the other hand, in the present embodiment, the flow velocity in the vicinity of the oxidant gas outlet 68 is made uniform as shown by the velocity contour in FIG. Therefore, the oxidant gas can be supplied uniformly and reliably to the oxidant gas supply communication hole 32a.

  Further, in the oxidant gas supply connecting pipe 54comp., As shown by the pressure contour line in FIG. 7, a remarkable pressure distribution was generated in the vicinity of the oxidant gas outlet 68comp. On the other hand, in this embodiment, a uniform pressure distribution is obtained in the vicinity of the oxidant gas outlet 68 as shown by the pressure contours in FIG. 8, and the oxidant gas is favorably supplied to the oxidant gas supply communication holes 32a. Can be supplied.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Fuel cell 18a, 18b ... End plate 26 ... Electrolyte membrane electrode assembly 28 ... Cathode side separator 30 ... Anode side separator 32a ... Oxidant gas supply communication hole 32b ... Oxidant gas discharge communication hole 34a ... fuel gas supply communication hole 34b ... fuel gas discharge communication hole 36a ... cooling medium supply communication hole 36b ... cooling medium discharge communication hole 38 ... solid polymer electrolyte membrane 40 ... cathode electrode 42 ... anode electrode 44 ... oxidant gas flow path 46 ... fuel gas flow path 48 ... cooling medium flow path 54a ... oxidant gas supply connection pipe 54ai ... inner wall surface 54b ... oxidant gas discharge connection pipe 56a ... fuel gas supply connection pipe 56b ... fuel gas discharge connection pipe 66 ... oxidant gas Inlet 68 ... Oxidant gas outlet 70 ... Pipe intermediate part 72 ... Swelling part

Claims (3)

A fuel cell in which an electrolyte membrane / electrode structure having electrodes provided on both sides of the electrolyte membrane and a separator are stacked; a plurality of the fuel cells are stacked; end plates are disposed at both ends in the stacking direction; In addition, a fluid communication hole for flowing at least a reaction gas or a fluid as a cooling medium is formed in the stacking direction of the fuel cell, and at least one of the end plates has a connection pipe that connects the fluid communication hole and an external pipe. A connected fuel cell stack,
The connecting pipe is provided with a fluid inlet connected to the external pipe, a fluid outlet connected to the fluid communication hole, and a curved cross section between the fluid inlet and the fluid outlet. A pipe intermediate part set to a larger opening cross-sectional area,
The pipe intermediate site, the opening range of the front view of the fluid outlet, have a bulging portion that bulges to the side opposite to the fluid inlet,
The fuel cell stack is characterized in that a portion constituting the inside of the curved shape of the pipe intermediate portion protrudes toward the opposite side of the fluid inlet and protrudes toward the bulging portion .   2. The fuel cell stack according to claim 1, wherein a fluid flow direction of the fluid inlet is set in a direction orthogonal to a fluid flow direction of the fluid communication hole. 3. 3. The fuel cell stack according to claim 1, wherein the pipe intermediate portion is a portion constituting an outer side of the curved shape of the pipe intermediate portion, and the fluid inlet side is located at a portion closer to the fluid inlet than the bulge portion. A fuel cell stack having a bulging region that bulges on the opposite side of the outlet.

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