JP4653978B2 - Fuel cell stack - Google Patents

Description

  The present invention has an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of an electrolyte, and the electrolyte / electrode structure and the separator are alternately stacked, and at least a cooling medium penetrates in the stacking direction. Alternatively, the present invention relates to a fuel cell stack in which a fluid communication hole through which any one of reaction gases flows is formed.

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

  In this fuel cell, a fuel gas, for example, a gas mainly containing hydrogen (hereinafter also referred to as hydrogen-containing gas) is supplied to the anode side electrode, while an oxidant gas, for example, A gas or air mainly containing oxygen (hereinafter also referred to as oxygen-containing gas) is supplied. In the fuel gas supplied to the anode side electrode, hydrogen is ionized on the electrode catalyst and moves to the cathode side electrode side through the electrolyte membrane. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy.

  In the above fuel cell, a fuel gas channel for flowing fuel gas to the anode side electrode and an oxidant gas channel for flowing oxidant gas to the cathode side 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.

  Generally, a fuel cell constitutes an internal manifold in which a fluid supply communication hole and a fluid discharge communication hole penetrating in the stacking direction of the separator are provided inside the fuel cell. The fuel gas, the oxidant gas, and the cooling medium, which are fluids, are supplied to the fuel gas flow path, the oxidant gas flow path, and the cooling medium flow path from the fluid supply communication holes, and then the fluid discharge communication holes. Have been discharged.

  As this type of internal manifold type fuel cell, “Fuel Cell Manifold” of Patent Document 1 is known. As shown in FIG. 5, this Patent Document 1 includes a module 1 in which a plurality of single cells are stacked, and a fuel cell stack 3 is configured by disposing end plates 2 at both ends of the module 1 in the stacking direction. ing. In the fuel cell stack 3, a refrigerant manifold 4, a fuel gas manifold 5, and an oxidant gas manifold (not shown) are provided so as to penetrate in the stacking direction.

  A flange 7 of the refrigerant pipe 6 a and the fuel gas pipe 6 b is screwed to the end plate 2, and fluid flow paths 8 a and 8 b communicating with the refrigerant manifold 4 and the fuel gas manifold 5 are formed in the flange 7. ing. O-ring grooves 9a and 9b are formed around the fluid flow paths 8a and 8b, and refrigerant and fuel gas are prevented from leaking between the end plate 2 and the flange 7 in the O-ring grooves 9a and 9b. O-rings R1 and R2 for mounting are mounted.

JP 2002-343406 A (FIG. 7)

  In the above-mentioned Patent Document 1, there is a possibility that a liquid junction may occur due to cooling water flowing through the refrigerant manifold 4 or generated water introduced into the fuel gas manifold 5, and when the cooling water or generated water comes into contact with the metal part, Corrosion due to electrical contact may be caused in this metal part.

  Therefore, it is desirable that the flange 7 of the refrigerant pipe 6a and the fuel gas pipe 6b be formed of resin fuel in order to prevent rust and the like due to electric contact. However, when the flange 7 is screwed to the end plate 2, the resin flange 7 is easily deformed, and the fluid flow paths 8 a and 8 b provided in the flange 7 and the end plate 2 are formed only by the O-rings R 1 and R 2. There is a problem that sufficient sealing performance with the refrigerant manifold 4 and the fuel gas manifold 5 cannot be secured.

  The present invention solves this type of problem, and can securely and firmly hold a resin sealing portion that seals the fluid communication hole in the fuel cell stack, and improves the sealing performance with a simple configuration. An object of the present invention is to provide a fuel cell stack that can be realized.

  The present invention has an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of an electrolyte, and the electrolyte / electrode structure and the separator are alternately stacked, and at least a cooling medium penetrates in the stacking direction. Alternatively, the fuel cell stack is formed with a fluid communication hole through which either of the reaction gas flows.

  The fuel cell stack is disposed in communication with the fluid communication hole, and has a flow path member having a flange portion, a superposition member that overlaps the flange portion in the stacking direction to form a seal portion, And a reinforcing member that is disposed so as to cover the region overlapping with the seal portion along the stacking direction and sandwich the flange portion with the seal portion.

  The reinforcing member is preferably formed of a material having a larger elastic coefficient than the flow path member. Further, end plates are disposed at both ends in the stacking direction of the fuel cell stack, and the overlapping member is an insulating cylindrical member disposed on the inner peripheral surface of the fluid flow path formed in at least one of the end plates. It is preferable.

  Furthermore, it is preferable that a lip-shaped seal portion constituting a seal portion is provided around the flange portion of the insulating cylindrical member.

  Moreover, it is preferable that a flow path member and a reinforcement member comprise the piping manifold connected to a fluid flow path, and the said piping manifold is attached to one end plate. Furthermore, it is preferable that the flow path member includes an undercut portion that holds the reinforcing member.

  Furthermore, the fluid communication hole includes a fuel gas supply communication hole for supplying fuel gas to the laminate of the electrolyte / electrode structure and the separator, and a fuel gas discharge communication hole for discharging the fuel gas from the stack, In the fuel gas supply part communicating with the fuel gas supply communication hole and the fuel gas discharge part communicating with the fuel gas discharge communication hole, it is preferable that all parts contacting the fuel gas are formed of resin.

  Here, a terminal plate, an insulating plate, an end plate, and a manifold as necessary are arranged on both sides of the laminate, and the fuel gas supply unit and the fuel gas discharge unit include, for example, the terminal plate, end plate, And provided in the manifold. When the manifold is configured only on one end plate and one terminal plate side, the fuel gas supply unit and the fuel gas discharge unit may not be provided on the other end plate and the other terminal plate side.

  The fluid communication hole includes a cooling medium supply communication hole that supplies a cooling medium and a cooling medium discharge communication hole that discharges the cooling medium, and includes a cooling medium supply unit that communicates with the cooling medium supply communication hole and the cooling medium discharge. As for the cooling medium discharge part connected to a communicating hole, it is preferable that all the parts which contact a cooling medium are formed with resin. A cooling medium supply part and a cooling medium discharge | emission part are provided in a terminal plate, an end plate, and a manifold, for example.

  According to the present invention, since the flange portion of the flow path member is sandwiched between the sealing portion and the reinforcing member of the overlapping member along the stacking direction, the seal portion is held only by the resin along the stacking direction. In comparison with the above, deformation or displacement of the seal portion is effectively prevented. Thereby, it is possible to prevent the occurrence of electrolytic corrosion with a simple configuration and to improve the sealing performance of the resin seal portion.

  FIG. 1 is a partially exploded perspective view of a fuel cell stack 10 according to the first embodiment of the present invention.

  The fuel cell stack 10 is mounted on a vehicle such as an automobile, for example. Although not shown, the fuel cell stack 10 includes an oxidant gas supply unit that supplies an oxidant gas, such as an oxygen-containing gas (such as air), and a fuel gas supply unit that supplies a fuel gas, such as a hydrogen-containing gas. And a cooling medium supply unit that supplies a cooling medium, such as pure water or ethylene glycol, is connected.

  The fuel cell stack 10 includes a stacked body 14 in which a plurality of power generation cells 12 are stacked in the direction of arrow A, and an end plate is interposed at both ends of the stacked body 14 with a terminal plate 16 and an insulating plate 18 interposed therebetween. 20a and 20b are arranged. The end plates 20a and 20b are fastened in the stacking direction by fastening bolts (not shown).

  Each power generation cell 12 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 22, and first and second metal separators 24 and 26 having a thin plate shape that sandwich the electrolyte membrane / electrode structure 22. . Instead of the first and second metal separators 24 and 26, for example, a carbon plate may be adopted.

  In order to supply an oxidant gas supply communication hole 28a for supplying an oxidant gas to one end edge of the long side direction (arrow B direction) of the power generation cell 12 in the direction of the arrow A to supply an oxidant gas. The cooling medium supply communication hole 30a and the fuel gas discharge communication hole 32b for discharging the fuel gas are provided.

  The other end edge of the power generation cell 12 in the long side direction communicates with each other in the direction of the arrow A, the fuel gas supply communication hole 32a for supplying fuel gas, and the cooling medium discharge communication hole for discharging the cooling medium. 30b and an oxidant gas discharge communication hole 28b for discharging the oxidant gas are provided.

  The electrolyte membrane / electrode structure 22 includes, for example, a solid polymer electrolyte membrane 34 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 36 and a cathode side electrode 38 that sandwich the solid polymer electrolyte membrane 34. With.

  The anode side electrode 36 and the cathode side electrode 38 are uniformly coated on the surface of the gas diffusion layer with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 34.

  The first metal separator 24 is provided with a fuel gas flow path 40 that communicates the fuel gas supply communication hole 32 a and the fuel gas discharge communication hole 32 b on the surface facing the electrolyte membrane / electrode structure 22. The first metal separator 24 is provided with a cooling medium flow path 42 that communicates the cooling medium supply communication hole 30a and the cooling medium discharge communication hole 30b on the opposite surface.

  The second metal separator 26 is provided with an oxidant gas flow path 44 on the surface facing the electrolyte membrane / electrode structure 22, and the oxidant gas flow path 44 communicates with the oxidant gas supply communication hole 28 a and the oxidant gas discharge communication. It communicates with the hole 28b. The second metal separator 26 overlaps with the first metal separator 24 on the opposite surface, and the cooling medium flow path 42 is integrally formed.

  The fuel gas flow path 40, the cooling medium flow path 42, and the oxidant gas flow path 44 are configured by, for example, a plurality of grooves extending in the direction of arrow B. A seal member (not shown) is integrally formed on the peripheral portions of the surfaces of the first and second metal separators 24 and 26.

  As shown in FIGS. 2 and 3, the oxidant gas supply communication hole 28a, the cooling medium supply communication hole 30a, the fuel gas discharge communication hole 32b, the fuel gas supply communication hole 32a, the cooling medium discharge communication hole 30b, and the oxidant gas discharge. On each rectangular inner peripheral surface of the communication hole 28b, an insulating cylindrical member, for example, an insulating grommet (polymerized member) 46 is disposed so as to straddle the terminal plate 16, the insulating plate 18 and the end plate 20a.

  The insulating grommet 46 is made of, for example, a sealing material such as EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroplane, or acrylic rubber, a cushioning material, or a packing material. The flange portions 50a and 50b are integrally formed at both ends of the body 48 which is the communication hole fitting portion. The flange portions 50a and 50b are provided with lip-shaped seal portions 52a and 52b protruding outward.

  The end plate 20a is formed with a plurality of screw holes 54a surrounding the oxidant gas supply communication hole 28a, the cooling medium supply communication hole 30a, and the fuel gas discharge communication hole 32b. A plurality of screw holes 54b are formed surrounding the medium discharge communication hole 30b and the oxidant gas discharge communication hole 28b.

  Piping manifolds 56 and 58 are fixed to the end plate 20 a on the surface opposite to the laminated body 14. The piping manifolds 56 and 58 are provided with mounting plate-like portions 60a and 60b disposed at both ends in the lateral direction (arrow B direction) of the end plate 20a. A plurality of holes 62a and 62b are formed coaxially with the screw holes 54a and 54b of the end plate 20a in each of the mounting plate-like parts 60a and 60b. Screws 63 are inserted into the holes 62a and 62b, and the tips of the screws 63 are screwed into the screw holes 54a and 54b, whereby the pipe manifolds 56 and 58 are fixed to the end plate 20a.

  Resin piping members (flow path members) 64a, 66a, and 68b communicating with the oxidant gas supply communication hole 28a, the cooling medium supply communication hole 30a, and the fuel gas discharge communication hole 32b are integrated with the mounting plate-like portion 60a. Arranged individually. The tubular piping members 64a, 66a and 68b are provided with a flange portion 69 and an undercut portion 71 at the respective base end portions.

  Further, the attachment plate-like portion 60a is formed of a resin having a larger elastic coefficient than the piping members 64a, 66a and 68b. The attachment plate-like portion 60a is provided with a reinforcing portion 70 disposed so as to cover the lip-like seal portion 52a of each insulating grommet 46, that is, the region H overlapping with the seal portion, in the stacking direction.

  The reinforcing portion 70 has a thin plate shape and is set in a shape corresponding to each rectangular inner peripheral surface, and is disposed in the undercut portions 71 of the piping members 64a, 66a, and 68b. The reinforcing portion 70 and the lip-shaped seal portion 52a which is a seal portion of the insulating grommet 46 sandwich the flange portion 69.

  Resin piping members (flow path members) 68a, 66b, and 64b communicating with the fuel gas supply communication hole 32a, the cooling medium discharge communication hole 30b, and the oxidant gas discharge communication hole 28b are integrated with the mounting plate-shaped portion 60b. Arranged individually. The attachment plate-like portion 60b is configured in the same manner as the attachment plate-like portion 60a described above, and the same components are denoted by the same reference numerals and detailed description thereof is omitted.

  In the pipe manifolds 56, 58, the mounting plate-like portions 60a, 60b are filled with the molten resin in a state in which the mounting plate-like portions 60a, 60b are disposed in a molding die (not shown), so that the flanges are attached to the mounting plate-like portions 60a, 60b. The part 69 and each undercut part 71 can be formed.

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

  First, the oxidant gas is supplied from the piping member 64 a to the oxidant gas supply communication hole 28 a of the fuel cell stack 10. On the other hand, the fuel gas is supplied from the piping member 68 a to the fuel gas supply communication hole 32 a of the fuel cell stack 10. Further, the cooling medium is supplied from the piping member 66 a to the cooling medium supply communication hole 30 a of the fuel cell stack 10.

  As shown in FIG. 1, in the fuel cell stack 10, oxidant gas is introduced into the oxidant gas flow path 44 of the second metal separator 26 from the oxidant gas supply communication hole 28 a, and the electrolyte membrane / electrode structure 22. It moves along the cathode side electrode 38. On the other hand, the fuel gas is introduced into the fuel gas flow path 40 of the first metal separator 24 from the fuel gas supply communication hole 32 a and moves along the anode side electrode 36 of the electrolyte membrane / electrode structure 22.

  Therefore, in each electrolyte membrane / electrode structure 22, the oxidant gas supplied to the cathode side electrode 38 and the fuel gas supplied to the anode side electrode 36 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 38 flows along the oxidant gas discharge communication hole 28b, and is then discharged to the piping member 64b connected to the end plate 20a. Similarly, the fuel gas consumed by being supplied to the anode side electrode 36 is discharged to the fuel gas discharge communication hole 32b, flows, and discharged to the piping member 68b connected to the end plate 20a.

  In addition, a cooling medium such as pure water or ethylene glycol is introduced into the cooling medium flow path 42 between the first and second metal separators 24 and 26 and then flows along the arrow B direction. This cooling medium cools the electrolyte membrane / electrode structure 22, then moves through the cooling medium discharge communication hole 30 b and is discharged to the piping member 66 b connected to the end plate 20 a for circulation.

  In this case, in the first embodiment, as shown in FIG. 3, the piping manifold 56 includes a resin piping member 64 a communicating with the oxidant gas supply communication hole 28 a, and the piping member 64 a and the insulating grommet 46. Are overlapping in the stacking direction. And the reinforcement part 70 which comprises the attachment plate-shaped part 60a is arrange | positioned at the undercut part 71 provided in the piping member 64a.

  The reinforcing portion 70 is disposed so as to cover the region H overlapping the lip-shaped seal portion 52a along the stacking direction, and the lip-shaped seal portion 52a is connected to the piping member 64a and the reinforcing portion 70 and the insulating grommet 46 (and the insulating grommet 46). It is clamped between the end plate 20a) on which the grommet 46 is mounted. That is, the flange portion 69 of the piping member 64a is sandwiched between the reinforcing portion 70 and the lip-shaped seal portion 52a.

  For this reason, when the lip-shaped seal portion 52a of the insulating grommet 46 is pressed against the flange portion 69 of the piping member 64a in a state where the piping manifold 56 is attached to the end plate 20a, the flange portion is under the holding action of the reinforcing portion 70. It is possible to effectively prevent 69 from being deformed or displaced. This is because the reinforcing portion 70 is made of a resin having a larger elastic coefficient than the piping member 64a.

  Thereby, it is possible to improve the sealing performance at the sealing portion between the resin piping member 64a and the insulating grommet 46 with a simple configuration, and the generated water or the cooling water is in contact with the metal mounting plate 60a. And there is an effect that the generation of rust and the like due to electrical contact can be reliably prevented.

  The piping members 64b, 66a, 66b, 68a and 68b and the insulating grommets 46 also have the same effect as the piping member 64a.

  Furthermore, in the first embodiment, the piping member 64 a is provided with an undercut portion 71, and the reinforcing portion 70 is accommodated and held in the undercut portion 71. Therefore, it is possible to reliably prevent the piping member 64a and the reinforcing portion 70 from separating from each other with a simple configuration.

  FIG. 4 is an enlarged cross-sectional view of a main part of a fuel cell stack 100 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.

  The fuel cell stack 100 includes an insulating grommet 46a attached to the end plate 20a, and an insulating grommet 46b attached integrally to the terminal plate 16 and the insulating plate 18.

  In the second embodiment configured as described above, the insulating grommet 46a and the piping manifolds 56 and 58 have the same effects as those of the first embodiment. In addition, in the insulating grommets 46a and 46b, the end portions of the end plate 20a and the insulating plate 18 are disposed so as to cover the region H1 that overlaps the lip-shaped seal portion 52b that is a mutual seal portion in the stacking direction. Thereby, even if a tightening force acts on the insulating grommets 46a and 46b in the stacking direction, it is possible to satisfactorily prevent the insulating grommets 46a and 46b from being deformed or displaced.

1 is a partially exploded perspective view of a fuel cell stack according to a first embodiment of the present invention. It is a perspective explanatory view of the piping manifold and insulating grommet which constitute the fuel cell stack. It is a cross-sectional explanatory drawing of the said piping manifold and the said insulation grommet. It is a section explanatory view of a piping manifold and insulating grommets which constitute a fuel cell stack concerning a 2nd embodiment of the present invention. FIG. 6 is an exploded perspective view of a manifold according to Patent Document 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,100 ... Fuel cell stack 12 ... Power generation cell 16 ... Terminal plate 18 ... Insulating plate 20a, 20b ... End plate 22 ... Electrolyte membrane and electrode structure 24, 26 Metal separator 28a ... Oxidant gas supply communication hole 28b ... Oxidant Gas discharge communication hole 30a ... Cooling medium supply communication hole 30b ... Cooling medium discharge communication hole 32a ... Fuel gas supply communication hole 32b ... Fuel gas discharge communication hole 40 ... Fuel gas flow path 42 ... Cooling medium flow path 44 ... Oxidant gas flow Path 46, 46a, 46b ... Insulation grommet 48 ... Body 50a, 50b, 69 ... Flange 52a, 52b ... Lip-like seal part 56, 58 ... Piping manifold 60a, 60b ... Mounting plate-like parts 64a, 64b, 66a, 66b, 68a, 68b ... piping member 70 ... reinforcing part 71 ... undercut part

Claims (6)

It has an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of the electrolyte, and the electrolyte / electrode structure and the separator are alternately stacked, and at least a cooling medium or a reactive gas penetrates in the stacking direction. A fuel cell stack in which a fluid communication hole for flowing either one is formed,
A flow path member disposed in communication with the fluid communication hole and having a flange portion;
A superposition member that overlaps the flange portion in the stacking direction and constitutes a seal portion;
A reinforcing member that is disposed on the outside in the radial direction of the flow path member, is disposed so as to cover a region overlapping with the seal portion along the stacking direction, and sandwiches the flange portion with the seal portion;
Equipped with a,
End plates are disposed at both ends in the stacking direction of the fuel cell stack,
The overlapping member is an insulating cylinder member disposed on an inner peripheral surface of the fluid communication hole formed in at least one end plate, and the sealing portion is configured in a flange portion of the insulating cylinder member a fuel cell stack lip seal portions which is characterized by Rukoto provided orbiting.   2. The fuel cell stack according to claim 1, wherein the reinforcing member is made of a material having a larger elastic coefficient than that of the flow path member. The fuel cell stack according to claim 1 or 2 , wherein the flow path member and the reinforcing member constitute a pipe manifold communicating with the fluid communication hole,
The fuel cell stack, wherein the pipe manifold is attached to the one end plate. The fuel cell stack according to any one of claims 1 to 3, wherein the flow path member is cut in order to retain said reinforcing member, radially inward of the flange portion from an outer periphery of the flange portion missing A fuel cell stack comprising an undercut portion. 2. The fuel cell stack according to claim 1, wherein the fluid communication hole includes a fuel gas supply communication hole that supplies fuel gas to a stack of the electrolyte / electrode structure and the separator, and the fuel gas is supplied from the stack. It has a fuel gas discharge communication hole for discharging
The fuel gas supply section communicating with the fuel gas supply communication hole and the fuel gas discharge section communicating with the fuel gas discharge communication hole are all formed of a resin in contact with the fuel gas. Battery stack. 2. The fuel cell stack according to claim 1, wherein the fluid communication hole includes a cooling medium supply communication hole that supplies a cooling medium and a cooling medium discharge communication hole that discharges the cooling medium,
The cooling medium supply part communicating with the cooling medium supply communication hole and the cooling medium discharge part communicating with the cooling medium discharge communication hole are all formed of a resin in contact with the cooling medium. stack.

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