JP2013161549A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell stack capable of surely discharging a stagnant water in a reactive gas exhausting continuous hole to the outside with a simple and compact structure.SOLUTION: A fuel cell stack 10 comprises a plurality of fuel cells 12, and a first end plate 20a and a second end plate 20b are provided on both edges in a lamination direction of fuel cells 12. A knock pin 62 for positioning a laminate 14 is arranged between the first end plate 20a and the second end plate 20b. A discharging channel 68 communicating an oxidant gas exhausting continuous hole 36b and the outside of the second end plate 20b, is arranged on the knock pin 62. The discharging channel 68 communicates with the oxidant gas exhausting continuous hole 36b via a connection channel 70 of an insulating plate 18b.

Description

  The present invention includes a laminate in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a fuel cell in which a separator is laminated, and end plates at both ends in the lamination direction of the laminate. The present invention relates to a fuel cell stack.

  For example, a polymer electrolyte fuel cell is a power generation cell in which an electrolyte membrane / electrode structure (MEA) in which an anode electrode and a cathode electrode are arranged on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched by separators. It has. This type of fuel cell is usually used as an in-vehicle fuel cell stack, for example, by stacking a predetermined number of power generation cells.

  In a fuel cell stack, an internal manifold is often configured to supply a fuel gas and an oxidant gas, which are reaction gases, to the anode electrode and the cathode electrode of each stacked power generation cell. The internal manifold includes a reaction gas supply communication hole and a reaction gas discharge communication hole that are provided through the power generation cell in the stacking direction.

  In this type of fuel cell stack, it is necessary to stack a large number of power generation cells, particularly when used for in-vehicle use. For this reason, each electric power generation cell must be positioned correctly, for example, the assembly method of the fuel cell currently disclosed by patent document 1 is known.

  As shown in FIG. 9, the assembling method is such that a cell assembly positioning hole 3 is formed in a pressurizing plate 2 for pressurizing the stack 1, and the positioning hole 3 is made of a long PTFE with a chamfered end surface. The knock pin 4 is inserted in an upright state. Next, the cells 5 in which the positioning holes 3 are formed are stacked in such a manner that the positioning holes 3 are sequentially fitted to the knock pins 4 and stacked. Thereafter, the stack 1 is fastened and fixed.

JP-A-9-134734

  By the way, during power generation of the fuel cell, generated water is generated on the cathode electrode side by an electrochemical reaction between hydrogen and oxygen. Since this generated water is discharged to the oxidant gas discharge communication hole (reactive gas discharge communication hole), the generated water condenses in the oxidant gas discharge communication hole, and stagnant water is likely to be generated. On the other hand, the produced water is back-diffused to the anode electrode side and discharged to the fuel gas discharge communication hole (reactive gas discharge communication hole). Therefore, the back diffused product water is condensed in the fuel gas discharge communication hole, and retained water is easily generated.

  At that time, in Patent Document 1 described above, in order to discharge the accumulated water in the reaction gas discharge communication hole to the outside of the stack 1, it is necessary to newly provide a dedicated drainage mechanism (drain mechanism). As a result, a space for a drainage mechanism must be provided in the stack 1, and the stack 1 is increased in size, and a dedicated seal structure is required, resulting in an increase in the number of parts.

  An object of the present invention is to solve this kind of problem, and to provide a fuel cell stack capable of reliably discharging the accumulated water in the reaction gas discharge communication hole to the outside with a simple and compact configuration. And

  The present invention includes a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and extends at least in the stacking direction of the plurality of fuel cells to react gas The present invention relates to a fuel cell stack provided with a stacked body provided with reaction gas discharge communication holes for discharging gas, and provided with end plates at both ends in the stacking direction of the stacked body.

  In this fuel cell stack, a rod member that extends in the stacking direction and is positioned between the end plates and serves as a knock pin for positioning the stack or a clamp pin that clamps and holds the stack integrally is disposed between the end plates. The rod member adjacent to the gas discharge communication hole is provided with a drainage flow path that connects the reaction gas discharge communication hole and the outside of the end plate.

  In this fuel cell stack, the fuel cells are preferably stacked in the horizontal direction in a standing posture, and the rod member is preferably disposed at a position equal to or lower than the height of the reaction gas discharge communication hole.

  Further, in this fuel cell stack, an insulating plate is disposed on the side of the end plate on the laminate side, and the insulating plate is connected to the reaction gas discharge communication hole and the drainage flow channel. Is preferably provided.

  According to the present invention, a rod member which is a knock pin for positioning the laminated body or a fastening pin for fastening and holding the laminated body integrally is provided, and the reactive gas discharge communication hole and the outside of the end plate are provided on the rod member. A drainage flow path is provided.

  For this reason, the accumulated water in the reaction gas discharge communication hole is discharged to the outside of the fuel cell stack through the drainage channel of the rod member. In addition, since the rod member itself functions as a drain mechanism, there is no need to provide a dedicated drain mechanism. Therefore, a dedicated seal structure or the like is not necessary, and an increase in the number of parts can be suppressed. This makes it possible to reliably discharge the accumulated water in the reaction gas discharge communication hole to the outside with a simple and compact configuration.

1 is a schematic perspective explanatory view of a fuel cell stack according to a first embodiment of the present invention. It is a partial cross section side view of the said fuel cell stack. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. It is front explanatory drawing of the 2nd separator which comprises the said fuel cell stack. It is a perspective view showing a knock pin of the fuel cell stack. FIG. 5 is a schematic perspective explanatory view of a fuel cell stack according to a second embodiment of the present invention. It is a partial cross section side view of the said fuel cell stack. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. 10 is an explanatory diagram of a method for assembling a fuel cell disclosed in Patent Document 1. FIG.

  As shown in FIG. 1, the fuel cell stack 10 according to the first embodiment of the present invention is a stack in which a plurality of fuel cells (power generation cells) 12 are stacked in a horizontal position (arrow B direction) in a standing posture. A body 14 is provided.

  As shown in FIGS. 1 and 2, the first end plate 20a and the second end plate 20b are arranged at both ends in the stacking direction of the stacked body 14 via terminal plates 16a and 16b and insulating plates 18a and 18b. Established. The terminal plates 16a and 16b are set to have a smaller surface area than the insulating plates 18a and 18b, and are accommodated in the openings 21a and 21b formed at the center of the insulating plates 18a and 18b (see FIG. 2).

  An output terminal 22a connected to the terminal plate 16a extends from the center of the first end plate 20a, while an output terminal 22b connected to the terminal plate 16b extends from the center of the second end plate 20b. Exists.

  As shown in FIG. 1, the first end plate 20 a and the second end plate 20 b have a horizontally long (or vertically long) rectangular shape, and a connecting bar 24 is disposed between each side. Each connecting bar 24 is fixed at both ends to the first end plate 20a and the second end plate 20b via bolts 26, and applies a tightening load in the stacking direction (arrow B direction) to the plurality of stacked fuel cells 12. .

  As shown in FIG. 3, the fuel cell 12 has a horizontally long (or vertically long) rectangular shape, and the electrolyte membrane / electrode structure 30 is sandwiched between the first separator 32 and the second separator 34. The 1st separator 32 and the 2nd separator 34 are comprised by metal separators and carbon separators, such as a steel plate, a stainless steel plate, an aluminum plate, or a plating treatment steel plate, for example.

  One end edge of the fuel cell 12 in the direction of arrow A (the horizontal direction in FIG. 3) communicates with each other in the direction of arrow B, which is the stacking direction, and oxidant for supplying an oxidant gas, for example, an oxygen-containing gas An agent gas supply communication hole 36a and a fuel gas discharge communication hole (reaction gas discharge communication hole) 38b for discharging a fuel gas, for example, a hydrogen-containing gas, are arranged in the arrow C direction (vertical direction).

  The other end edge of the fuel cell 12 in the direction of arrow A communicates with each other in the direction of arrow B, and an oxidant gas discharge communication hole (reactive gas discharge communication hole) 36b for discharging oxidant gas, and fuel gas Are provided in the direction indicated by the arrow C.

  A coolant supply passage 40a for supplying a coolant is provided at the upper edge of the fuel cell 12 in the arrow C direction, and the coolant is provided at the lower edge of the fuel cell 12 in the arrow C direction. Is provided with a cooling medium discharge communication hole 40b.

  An oxidant gas flow path 42 communicating with the oxidant gas supply communication hole 36 a and the oxidant gas discharge communication hole 36 b is provided on the surface 32 a of the first separator 32 facing the electrolyte membrane / electrode structure 30. The oxidant gas flow channel 42 has a plurality of serpentine-shaped flow channel grooves 42a meandering in the vertical direction (the direction of arrow C).

  As shown in FIG. 4, the surface 34a of the second separator 34 facing the electrolyte membrane / electrode structure 30 is provided with a fuel gas passage 44 communicating with the fuel gas supply communication hole 38a and the fuel gas discharge communication hole 38b. It is done. The fuel gas channel 44 has a plurality of serpentine-shaped channel grooves 44a meandering in the vertical direction (direction of arrow C).

  A cooling medium that connects the cooling medium supply communication hole 40a and the cooling medium discharge communication hole 40b between the surface 32b of the first separator 32 and the surface 34b of the second separator 34 that constitute the fuel cells 12 adjacent to each other. A flow path 46 is provided (see FIG. 3).

  The first separator 32 and the second separator 34 are respectively provided with seal members 48 and 50 integrally or individually. The seal members 48 and 50 use, for example, a seal material such as EPDM, NBR, fluoro rubber, silicon rubber, fluorosilicon rubber, butyl rubber, natural rubber, styrene rubber, chloroplane, or acrylic rubber, a cushion material, or a packing material. To do.

  The electrolyte membrane / electrode structure 30 includes, for example, a solid polymer electrolyte membrane 52 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode electrode 54 and an anode electrode 56 that sandwich the solid polymer electrolyte membrane 52. Prepare.

  The cathode electrode 54 and the anode electrode 56 are an electrode catalyst formed by uniformly applying a gas diffusion layer 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 having a layer. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 52.

  In one diagonal position of the fuel cell 12, specifically, positioning holes 58 and 60 are provided in the vicinity of the oxidant gas discharge communication hole 36b and in the vicinity of the fuel gas discharge communication hole 38b, respectively. As shown in FIG. 4, the positioning hole 58 is located outside the oxidant gas discharge communication hole 36b and below the height of the oxidant gas discharge communication hole 36b (including the same height, the same applies hereinafter). Is provided. Similarly, the positioning hole 60 is provided outside the fuel gas discharge communication hole 38b and at a position below the height of the fuel gas discharge communication hole 38b.

  As shown in FIG. 5, the first end plate 20 a and the second end plate 20 b extend in the stacking direction and are cylindrical knock pins (rod members) that are integrally inserted into the positioning holes 58 and 60. ) 62 and 64 are disposed. The knock pins 62 and 64 are preferably fitted in the positioning holes 58 and 60 without any gaps.

  The knock pins 62 and 64 are preferably formed of a resin such as SUS (stainless steel), aluminum, iron, PPS (polyphenylene sulfide), carbon, or the like. The knock pins 62 and 64 are held on the first end plate 20a and the second end plate 20b by nuts 66, respectively.

  As shown in FIG. 2, the knock pin 62 is provided with a drainage flow path 68 that communicates the oxidizing gas discharge communication hole 36 b and the outside of the second end plate 20 b. The drainage flow path 68 extends from the end of the knock pin 62 on the second end plate 20 b side to the position corresponding to the insulating plate 18 b inward in the axial direction, and then bends and opens from the outer periphery of the knock pin 62. . The drainage flow path 68 may be formed from the end portion of the knock pin 62 on the first end plate 20a side depending on the layout or the like.

  The insulating plate 18 b is provided with a connecting channel 70 that communicates the oxidizing gas discharge communication hole 36 b and the drainage channel 68. The connection channel 70 has a bent shape, and a portion extending in the stacking direction communicates with the oxidant gas discharge communication hole 36b, while a portion extending in the direction crossing the stacking direction is a flow for drainage. It communicates with the road 68.

  A seal member (O-ring) 72 is disposed at a boundary portion between the connection channel 70 and the drainage channel 68 so as to surround the opening of the drainage channel 68 of the knock pin 62. Instead of the seal member 72, a pair of seal members (O-rings) 72 a may be provided around the knock pins 62 on both sides of the opening of the drainage flow path 68.

  The knock pin 64 is configured in the same manner as the knock pin 62 described above, and is provided with a drainage flow path 68 that communicates the fuel gas discharge communication hole 38b and the outside of the second end plate 20b (see FIG. 5). Other detailed explanation is omitted.

  As shown in FIG. 1, the first end plate 20a includes an oxidant gas supply communication hole 36a, an oxidant gas discharge communication hole 36b, a fuel gas supply communication hole 38a, a fuel gas discharge communication hole 38b, and a cooling medium supply communication hole. 40a and a cooling medium discharge communication hole 40b are formed, and a manifold member is connected to these, though not shown.

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

  First, as shown in FIG. 3, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas supply communication hole 36a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas supply communication hole 38a. Further, a coolant such as pure water, ethylene glycol, or oil is supplied to the coolant supply passage 40a.

  For this reason, the oxidant gas is introduced into the oxidant gas flow path 42 of the first separator 32 from the oxidant gas supply communication hole 36a. The oxidant gas is supplied to the cathode electrode 54 constituting the electrolyte membrane / electrode structure 30 while meandering in the vertical direction along the plurality of flow channel grooves 42a.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 44 of the second separator 34 from the fuel gas supply communication hole 38a. The fuel gas is supplied to the anode electrode 56 constituting the electrolyte membrane / electrode structure 30 while meandering in the vertical direction along the plurality of flow passage grooves 44a.

  Therefore, in the electrolyte membrane / electrode structure 30, the oxidant gas supplied to the cathode electrode 54 and the fuel gas supplied to the anode electrode 56 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is called.

  Subsequently, the oxidant gas consumed by being supplied to the cathode electrode 54 is discharged in the direction of arrow B along the oxidant gas discharge communication hole 36b. On the other hand, the fuel gas supplied to and consumed by the anode electrode 56 is discharged in the direction of arrow B along the fuel gas discharge communication hole 38b.

  The cooling medium supplied to the cooling medium supply communication hole 40 a is introduced into the cooling medium flow path 46 between the first separator 32 and the second separator 34 and then circulates in the direction of arrow C. The cooling medium is discharged from the cooling medium discharge communication hole 40b after the electrolyte membrane / electrode structure 30 is cooled.

  By the way, in each fuel cell 12, generated water is generated on the cathode electrode 54 side by the above-described electrochemical reaction. This generated water is discharged from the oxidant gas passage 42 to the oxidant gas discharge communication hole 36b. On the other hand, in the anode electrode 56, the generated water is reversely diffused, and this generated water is discharged from the fuel gas flow path 44 to the fuel gas discharge communication hole 38b.

  In this case, in the first embodiment, as shown in FIG. 2, the knock pin 62 is provided with a drainage flow path 68 that communicates the oxidizing gas discharge communication hole 36b and the outside of the second end plate 20b. Yes. The insulating plate 18b is provided with a connecting channel 70 that communicates the oxidizing gas discharge communication hole 36b and the drainage channel 68.

  Therefore, the accumulated water in the oxidant gas discharge communication hole 36b is discharged from the connection channel 70 of the insulating plate 18b to the outside of the fuel cell stack 10 through the drainage channel 68 of the knock pin 62.

  Moreover, since the knock pin 62 itself functions as a drain mechanism, it is not necessary to provide a dedicated drain mechanism. Therefore, a dedicated seal structure or the like is not necessary, and an increase in the number of parts can be suppressed. Thereby, the effect that it becomes possible to discharge | emit the staying water of the oxidant gas discharge | emission communication hole 36b reliably outside with a simple and compact structure is acquired.

  On the other hand, the knock pin 64 is provided with a drainage flow path 68 that connects the fuel gas discharge communication hole 38b and the outside of the second end plate 20b (see FIG. 5). For this reason, the effect that it becomes possible to discharge | emit the stagnant water of the fuel gas discharge communicating hole 38b outside reliably with a simple and compact structure is acquired.

  FIG. 6 is an exploded perspective view of a fuel cell stack 80 according to the second embodiment of the present invention. The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 6 and 7, the fuel cell stack 80 includes a stacked body 14 in which a plurality of fuel cells (power generation cells) 82 are stacked in the horizontal direction (arrow B direction) in a standing posture. A first end plate 84a and a second end plate 84b are disposed at both ends in the stacking direction of the fuel cell stack 80, and the fuel cell stack 80 includes the first end plate 84a and the second end plate 84b. Are clamped and held in the stacking direction by four clamping pins (rod members) 86a, 86b, 86c and 86d. A nut 88 is screwed into the fastening pins 86a, 86b, 86c and 86d.

  As shown in FIG. 8, in the fuel cell 82, the electrolyte membrane / electrode structure 90 is sandwiched between the first separator 92 and the second separator 94. The 1st separator 92 and the 2nd separator 94 are comprised by metal separators and carbon separators, such as a steel plate, a stainless steel plate, an aluminum plate, or a plating treatment steel plate, for example.

  In the fuel cell 82, the positions of the oxidant gas supply communication hole 36a and the fuel gas discharge communication hole 38b are opposite to those of the fuel cell 12 according to the first embodiment. The oxidant gas channel 42 has a plurality of linear channel grooves 42b extending in the direction of arrow A, and the fuel gas channel 44 similarly has a plurality of linear flow channels extending in the direction of arrow A. It has a road groove 44b.

  At the corner of the fuel cell 82, that is, in the vicinity of the oxidant gas discharge communication hole 36b, in the vicinity of the fuel gas supply communication hole 38a, in the vicinity of the oxidant gas supply communication hole 36a and in the vicinity of the fuel gas discharge communication hole 38b. Circular openings 96a, 96b, 96c and 96d are provided.

  The opening 96a is provided outside the oxidant gas discharge communication hole 36b and at a position below the height of the oxidant gas discharge communication hole 36b. Similarly, the opening 96d is provided outside the fuel gas discharge communication hole 38b and at a position below the height of the fuel gas discharge communication hole 38b. The fastening pins 86a, 86b, 86c and 86d are inserted into the openings 96a, 96b, 96c and 96d with a gap, for example.

  As shown in FIG. 7, the clamping pin 86a is provided with a drainage flow path 68 that communicates the oxidizing gas discharge communication hole 36b and the outside of the second end plate 84b. The insulating plate 18b is provided with a connecting flow path 70 that communicates the oxidizing gas discharge communication hole 36b and the drainage flow path 68 of the clamping pin 86a. Similarly, the fastening pin 86d is provided with a drainage channel (not shown) that communicates the fuel gas discharge communication hole 38b and the outside of the second end plate 84b.

  In the second embodiment configured as described above, the fastening pin 86a is provided with a drainage flow path 68 that communicates the oxidizing gas discharge communication hole 36b and the outside of the second end plate 84b. The fastening pin 86d is also provided with a drainage channel (not shown) that communicates the fuel gas discharge communication hole 38b and the outside of the second end plate 84b. The insulating plate 18b is provided with a connection channel 70 that connects the oxidant gas discharge communication hole 36b and the drainage channel 68, and a connection channel that connects the fuel gas discharge communication hole 38b and the drainage channel. It has been. That is, the fastening pins 86a and 86d can also function as a drain mechanism.

  Thereby, with the simple and compact configuration, it is possible to reliably discharge the staying water in the oxidant gas discharge communication hole 36b to the outside, and the same effects as in the first embodiment can be obtained.

  In the second embodiment, the fastening pins 86a to 86d are inserted into the openings 96a to 96d provided in the fuel cell 82 in the stacking direction, but the present invention is not limited to this.

  For example, the first end plate 84a, the second end plate 84b, and the insulating plate 18b may be set to have outer dimensions larger than those of the fuel cell 82, and the clamping pins 86a to 86d may be disposed outside the fuel cell 82. . That is, the fuel cell 82 is not provided with the openings 96a to 96d, and the fastening pins 86a to 86d may be configured to be inserted into the first end plate 84a, the second end plate 84b, and the insulating plate 18b. Good.

DESCRIPTION OF SYMBOLS 10, 80 ... Fuel cell stack 12, 82 ... Fuel cell 14 ... Laminated body 20a, 20b, 84a, 84b ... End plate 30, 90 ... Electrolyte membrane and electrode structure 32, 34, 92, 94 ... Separator 36a ... Oxidant Gas supply communication hole 36b ... Oxidant gas discharge communication hole 38a ... Fuel gas supply communication hole 38b ... Fuel gas discharge communication hole 40a ... Cooling medium supply communication hole 40b ... Cooling medium discharge communication hole 42 ... Oxidant gas flow path 44 ... Fuel Gas channel 46 ... cooling medium channel 52 ... solid polymer electrolyte membrane 54 ... cathode electrode 56 ... anode electrode 58, 60 ... positioning hole 62, 64 ... knock pin 68 ... drain channel 70 ... connection channel 72, 72a ... Seal members 86a-86d ... Fastening pins 96a-96d ... Openings

Claims (3)

A reaction having a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked and extending in the stacking direction of at least a plurality of the fuel cells to discharge a reaction gas A fuel cell stack comprising a stack provided with gas discharge communication holes, and provided with end plates at both ends in the stacking direction of the stack,
Between the end plates, a rod member that extends in the laminating direction and is a knock pin for positioning the laminated body or a fastening pin for fastening and holding the laminated body integrally is disposed,
The fuel cell stack according to claim 1, wherein the rod member adjacent to the reaction gas discharge communication hole is provided with a drainage flow path that connects the reaction gas discharge communication hole and the outside of the end plate. The fuel cell stack according to claim 1, wherein the fuel cells are stacked horizontally in a standing posture,
The fuel cell stack, wherein the rod member is disposed at a position equal to or lower than a height of the reaction gas discharge communication hole. The fuel cell stack according to claim 1 or 2, wherein an insulating plate is disposed on a side portion of the end plate on the stacked body side,
The fuel cell stack according to claim 1, wherein the insulating plate is provided with a connection channel that communicates the reactive gas discharge passage and the drain channel.

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