JP2011028939A - Fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent blocking of a channel caused by the collapse of a connecting bridge to the utmost, with an economical and a simple structure. <P>SOLUTION: A fuel cell 12 making up the fuel cell stack 10 is formed by holding an electrolytic film-electrode structure 14 between a first metal separator 16 and a second metal separator 18. The first metal separator 16 is provided with a connecting bridge 28a communicatively connecting an oxidizer gas channel 26 to an oxidizer gas inlet communicating hole 20a. The connecting bridge 28a has a plurality of resin passage members 32a arranged intermittently apart from each other on a surface 16a, where passages 33a are formed between the resin passage members 32a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the present invention, an electrolyte / electrode structure having a pair of electrodes disposed on both sides of an electrolyte and a metal separator are laminated, and at least a fluid that is any one of a fuel gas, an oxidant gas, and a cooling medium is supplied to the metal separator. The present invention relates to a fuel cell stack in which a fluid flow path that flows in the direction of the surface and fluid communication holes that supply the fluid in the stacking direction are formed.

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

  In the fuel cell described above, a fuel gas channel (fluid channel) for flowing a fuel gas (fluid) facing the anode side electrode and an oxidant gas (face) facing the cathode side electrode in the plane of the separator. And an oxidant gas flow path (fluid flow path) for flowing a fluid. Further, a fuel gas inlet communication hole and a fuel gas outlet communication hole that are fluid communication holes that penetrate the separator in the stacking direction and communicate with the fuel gas flow path, and an oxidant gas flow path An oxidant gas inlet communication hole and an oxidant gas outlet communication hole, which are fluid communication holes communicating with each other, are formed.

  A cooling medium flow path (fluid flow path) for cooling the electrolyte membrane / electrode structure is provided between the separators, and a fluid communication hole that penetrates in the stacking direction and communicates with the cooling medium flow path. A cooling medium inlet communication hole and a cooling medium outlet communication hole are formed. That is, an internal manifold type fuel cell is configured.

  In that case, the fluid flow path and the fluid communication hole communicate with each other via a connection flow path (connection bridge portion) having parallel grooves and the like in order to flow the fluid smoothly and evenly. However, when the separator and the electrolyte / electrode structure are clamped and fixed with a seal member interposed therebetween, the seal member enters the connecting flow path, and the desired sealing performance cannot be maintained. In addition, there is a problem that the fluid does not flow well.

  Therefore, in the polymer electrolyte fuel cell stack disclosed in Patent Document 1, a meandering reaction gas, for example, an oxidant gas flow path 2 is formed in the plane of the separator 1 as shown in FIG. . The oxidant gas flow channel 2 communicates with an oxidant gas supply through hole 3 and an oxidant gas discharge through hole 4 that penetrate the peripheral edge of the separator 1 in the stacking direction. A packing 5 is disposed in the separator 1, and the through holes 3, 4 and the oxidant gas flow path 2 are communicated with each other in the plane of the separator 1, and other through holes are sealed from these.

  In the connection channels 6a and 6b that connect the through holes 3 and 4 and the oxidant gas channel 2, the SUS plate 7 is disposed so as to cover the connection channels 6a and 6b. The SUS plate 7 is configured in a rectangular shape, and ears 7a and 7b are provided at two locations, respectively, and the ears 7a and 7b are fitted into a step 8 formed on the separator 1.

  Thus, in Patent Document 1, since the SUS plate 7 covers the connection flow paths 6a and 6b, the polymer film (not shown) and the packing 5 do not fall into the oxidant gas flow path 2, The desired sealing performance can be ensured, and an increase in the pressure loss of the reaction gas can be prevented.

JP 2001-266911 A

  In the above Patent Document 1, there are cases where the connecting flow paths 6a and 6b are formed on the surface of the separator 1 via rubber bridges (rubber flow path members). However, there is a possibility that the connection flow paths 6a and 6b may be blocked due to deformation of the rubber bridge due to fluctuations in the load on the seal, durability deterioration of the rubber, and the like. For this reason, the supply failure of oxidant gas etc. arises and there exists a problem that the output performance of a fuel cell falls.

  The present invention solves this type of problem, and provides a fuel cell stack capable of preventing as much as possible blockage of a flow path due to collapse of a connecting bridge portion with an economical and simple configuration. With the goal.

  In the present invention, an electrolyte / electrode structure having a pair of electrodes disposed on both sides of an electrolyte and a metal separator are laminated, and at least a fluid that is any one of a fuel gas, an oxidant gas, and a cooling medium is supplied to the metal separator. The present invention relates to a fuel cell stack in which a fluid flow path that flows in the surface direction and a fluid communication hole that supplies the fluid in the stacking direction are formed.

  The metal separator is provided with a connection bridge portion that communicates between the fluid flow path and the fluid communication hole, and the connection bridge portion includes a resin passage member that is provided integrally with the metal separator. Yes.

  A covering member is preferably interposed between the metal separator and the resin passage member.

  Furthermore, it is preferable that the plurality of resin passage members are intermittently spaced apart from each other on the metal separator.

  Furthermore, it is preferable that the plurality of resin passage members are continuously formed on the metal separator via the resin connection portion.

  Moreover, it is preferable that the resin-made passage members are integrally formed on both surfaces of the metal separator through openings provided in the metal separator.

  Furthermore, it is preferable that a seal member is integrally formed on the metal separator, and the resin-made passage member and the seal member are formed by overlapping a part of each other in the stacking direction.

  According to this invention, since a connection bridge part has a resin-made channel | path member, the dimensional change by durability deterioration can be favorably suppressed compared with a rubber bridge part. Therefore, it is possible to prevent as much as possible the blockage of the flow path due to the collapse of the connecting bridge portion with an economical and simple configuration, ensuring a smooth flow of the fluid and ensuring the desired output performance. can do.

1 is an exploded perspective view of a main part of a fuel cell constituting a fuel cell stack according to a first embodiment of the present invention. FIG. 2 is a sectional view of the fuel cell stack taken along line II-II in FIG. 1. It is explanatory drawing of one surface of the 1st metal separator which comprises the said fuel cell stack. It is principal part perspective explanatory drawing of the said 1st metal separator. It is explanatory drawing of one surface of the 2nd metal separator which comprises the said fuel cell stack. It is a principal part perspective explanatory drawing of the 1st metal separator which comprises the fuel cell stack which concerns on the 2nd Embodiment of this invention. It is principal part perspective explanatory drawing of the 1st metal separator which comprises the fuel cell stack which concerns on the 3rd Embodiment of this invention. It is principal part perspective explanatory drawing of the 1st metal separator which comprises the fuel cell stack which concerns on the 4th Embodiment of this invention. It is principal part perspective explanatory drawing of the 1st metal separator which comprises the fuel cell stack which concerns on the 5th Embodiment of this invention. It is principal part perspective explanatory drawing of the 1st metal separator which comprises the fuel cell stack concerning the 6th Embodiment of this invention. It is principal part cross-sectional explanatory drawing of the fuel cell stack which concerns on the 7th Embodiment of this invention. It is principal part perspective explanatory drawing of the 1st metal separator which comprises the said fuel cell stack. It is explanatory drawing of the separator which comprises the fuel cell stack currently disclosed by patent document 1. FIG.

  As shown in FIGS. 1 and 2, the fuel cell stack 10 according to the first embodiment of the present invention has a plurality of fuel cells 12 stacked in the horizontal direction (arrow A direction) or the vertical direction (arrow C direction). Configured.

  In the fuel cell 12, an electrolyte membrane / electrode structure (electrolyte / electrode structure) 14 is sandwiched between a first metal separator 16 and a second metal separator 18. The first metal separator 16 and the second metal separator 18 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or the like, and are pressed into a corrugated plate shape to form a flow path to be described later. ing.

  As shown in FIG. 1, one end edge of the fuel cell 12 in the arrow B direction (horizontal direction in FIG. 1) communicates with each other in the arrow A direction, which is the stacking direction, and contains an oxidant gas, for example, oxygen An oxidant gas inlet communication hole 20a for supplying gas, a cooling medium inlet communication hole 22a for supplying a cooling medium, and a fuel gas outlet communication hole 24b for discharging a fuel gas, for example, a hydrogen-containing gas, Arranged in the direction of arrow C (vertical direction).

  The other end edge of the fuel cell 12 in the direction of arrow B communicates with each other in the direction of arrow A, the fuel gas inlet communication hole 24a for supplying fuel gas, and the cooling medium outlet communication hole for discharging the cooling medium. 22b and an oxidant gas outlet communication hole 20b for discharging the oxidant gas are arranged in the direction of arrow C.

  As shown in FIGS. 1 and 3, an oxidant gas channel (fluid channel) 26 extending in the direction of arrow B is provided on the surface 16a of the first metal separator 16 on the electrolyte membrane / electrode structure 14 side. It is done. The oxidant gas flow path 26 includes a plurality of grooves provided by forming the first metal separator 16 into a wave shape. The oxidant gas flow path 26 communicates with the oxidant gas inlet communication hole 20a and the oxidant gas outlet communication hole 20b through connection bridge portions 28a and 28b. A part of the coolant flow path 29 that is the back surface shape of the oxidant gas flow path 26 is formed on the surface 16 b of the first metal separator 16.

  A first seal member (rubber seal member) 30 is integrally formed on the surfaces 16a and 16b of the first metal separator 16 by injection molding or the like around the outer peripheral edge of the first metal separator 16. The first seal member 30 uses, for example, a seal material such as EPDM, NBR, fluorine rubber, silicon rubber, fluorosilicon rubber, butyl rubber, natural rubber, styrene rubber, chloroplane, or acrylic rubber, a cushion material, or a packing material. To do.

  As shown in FIGS. 3 and 4, the connecting bridge portion 28a includes a plurality of resin passage members 32a that are spaced apart from each other on the surface 16a and are intermittently arranged in the direction of the arrow C. A passage 33a is formed between 32a. The resin-made passage member 32a may be integrally formed on the surface 16a of the first metal separator 16 by, for example, insert molding or the like, or may be integrally formed by being attached to the surface 16a after being formed separately. .

  The resin passage member 32a is made of, for example, PPS (polyphenylene sulfide), LCP (liquid crystal polymer), PTFE (polytetrafluoroethylene), PA (polyamide), PEN (polyether nitrile), or PEEK (polyether ether ketone). Composed.

  Similarly to the above-described connection bridge portion 28a, the connection bridge portion 28b includes a plurality of resin passage members 32b, and a passage 33b is formed between the resin passage members 32b, and detailed description thereof is omitted. (See FIG. 3).

  As shown in FIGS. 1 and 5, the surface 18a of the second metal separator 18 on the electrolyte membrane / electrode structure 14 side communicates with the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b. A fuel gas channel (fluid channel) 34 extending in the direction is formed. The fuel gas flow path 34 includes a plurality of grooves, and the fuel gas flow path 34 communicates with the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b via connection bridge portions 36a and 36b. A part of the coolant flow path 29 that is the back surface shape of the fuel gas flow path 34 is formed on the surface 18 b of the second metal separator 18.

  A second seal member (rubber seal member) 38 is integrally formed on the surfaces 18a and 18b of the second metal separator 18 by injection molding or the like around the outer peripheral end portion of the second metal separator 18. The second seal member 38 is configured the same as the first seal member 30.

  As shown in FIG. 5, the connecting bridge portion 36a has a plurality of resin passage members 40a arranged in the direction of arrow C, and a passage 42a is formed between the resin passage members 40a. Similarly, the connecting bridge portion 36b has a plurality of resin passage members 40b, and a passage 42b is formed between the resin passage members 40b.

  As shown in FIG. 1, a cooling medium flow path (fluid flow path) communicating with the cooling medium inlet communication hole 22 a and the cooling medium outlet communication hole 22 b is provided on a surface 18 b opposite to the surface 18 a of the second metal separator 18. 29 is formed. Connection bridge portions 44a and 44b are formed in the vicinity of the cooling medium inlet communication hole 22a and the cooling medium outlet communication hole 22b. The connecting bridge portions 44a and 44b have a plurality of resin passage members 46a and 46b arranged in the direction of arrow C, and passages 48a and 48b are formed between the resin passage members 46a and 46b.

  As shown in FIGS. 1 and 2, the electrolyte membrane / electrode structure 14 includes, for example, a solid polymer electrolyte membrane 50 in which a perfluorosulfonic acid thin film is impregnated with water, and the solid polymer electrolyte membrane 50 sandwiched between them. An anode side electrode 52 and a cathode side electrode 54 are provided.

  The anode side electrode 52 and the cathode side electrode 54 are composed of a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles having a platinum alloy supported on the surface are uniformly applied to the surface of the gas diffusion layer. And have. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 50 so as to face each other with the solid polymer electrolyte membrane 50 interposed therebetween.

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

  First, as shown in FIG. 1, a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 24a, and an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 20a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 22a.

  Therefore, as shown in FIG. 5, the fuel gas is introduced into the fuel gas flow path 34 after passing through the connection bridge portion 36 a from the fuel gas inlet communication hole 24 a of the second metal separator 18. In the fuel gas passage 34, the fuel gas is supplied to the anode side electrode 52 constituting the electrolyte membrane / electrode structure 14 while moving in the arrow B direction.

  On the other hand, as shown in FIGS. 2 to 4, the oxidant gas is introduced from the oxidant gas inlet communication hole 20 a to the first metal separator 16 through the connection bridge portion 28 a and into the oxidant gas flow path 26. As a result, the oxidant gas is supplied to the cathode side electrode 54 constituting the electrolyte membrane / electrode structure 14 while moving in the direction of the arrow B in the oxidant gas flow path 26.

  Therefore, in the electrolyte membrane / electrode structure 14, the oxidant gas supplied to the cathode side electrode 54 and the fuel gas supplied to the anode side electrode 52 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the consumed fuel gas supplied to the anode side electrode 52 is discharged to the fuel gas outlet communication hole 24b through the connection bridge portion 36b (see FIG. 5). Similarly, the oxidant gas supplied and consumed by the cathode side electrode 54 is discharged to the oxidant gas outlet communication hole 20b through the connection bridge portion 28b (see FIG. 3).

  Further, as shown in FIG. 1, the cooling medium supplied to the cooling medium inlet communication hole 22a is introduced into the cooling medium flow path 29 between the first and second metal separators 16 and 18 through the connection bridge portion 44a. After that, it circulates in the arrow B direction. The cooling medium cools the electrolyte membrane / electrode structure 14 and then is discharged to the cooling medium outlet communication hole 22b through the connection bridge portion 44b.

  In this case, in the first embodiment, as shown in FIGS. 2 to 4, the connecting bridge portion 28 a provided in the first metal separator 16 has a plurality of resin passage members 32 a arranged in the direction of arrow C. A passage 33a is formed between the resin passage members 32a.

  For this reason, the connection bridge part 28a can suppress the dimensional change by durability deterioration favorably compared with a normal rubber bridge part. Moreover, it is difficult for the fuel cell 12 to be compressed and deformed due to the stack load. Accordingly, it is possible to prevent the passage 33a from being blocked by the collapse of the connecting bridge portion 28a as much as possible with an economical and simple configuration, and the fuel cell 12 ensures a smooth flow of the oxidant gas. The effect that the desired output performance can be reliably maintained is obtained.

  Similarly, in the other connecting bridge portions 28b, 36a, 36b, 44a and 44b, it is possible to ensure smooth circulation of the fuel gas and the cooling medium. The same applies to the second and subsequent embodiments described below.

  As shown in FIG. 6, the 1st metal separator 60 which comprises the fuel cell stack which concerns on the 2nd Embodiment of this invention provides the connection bridge | bridging part 62a. The connection bridge portion 62a has a plurality of resin passage members 66a arranged continuously in the direction of arrow C via the resin connection portion 64a on the surface 60a of the first metal separator 60, and the resin passage member. A passage 68a is formed between 66a.

  In the second embodiment configured as described above, no gap is particularly generated between the connecting bridge portion 62 a and the first metal separator 60. This makes it possible to prevent potential difference corrosion of the first metal separator 60 as much as possible, and obtain the same effects as those of the first embodiment. In addition, since the plurality of resin passage members 66a are integrally formed through the resin connection portion 64a, the manufacture is facilitated and the removal from the first metal separator 60 is prevented as much as possible. Can do.

  As shown in FIG. 7, the 1st metal separator 70 which comprises the fuel cell stack which concerns on the 3rd Embodiment of this invention provides the connection bridge | bridging part 72a. The connecting bridge portion 72a is provided on the surface 70a of the first metal separator 70, and includes a plurality of resin passage members 76a arranged continuously in the direction of arrow C between the resin connecting portions 74a, 74a on both sides. Have. A passage 78a is formed between the resin passage members 76a.

  In the third embodiment configured as described above, the same effects as those of the first and second embodiments can be obtained. Furthermore, it is possible to prevent the passage 78a from being blocked as much as possible.

  As shown in FIG. 8, the 1st metal separator 80 which comprises the fuel cell stack which concerns on the 4th Embodiment of this invention provides the connection bridge | bridging part 28a of 1st Embodiment. Between the first metal separator 80 and the resin-made passage member 32a constituting the connection bridge portion 28a, a covering member, for example, a rubber covering molding portion 82 is interposed.

  The rubber coating forming part 82 is formed on the surface 80a of the first metal separator 80 integrally with the first seal member 30 or separately. The rubber covering molding portion 82 may be composed of a rubber film. The same applies to the fifth and sixth embodiments described below.

  As shown in FIG. 9, the 1st metal separator 90 which comprises the fuel cell stack which concerns on the 5th Embodiment of this invention provides the connection bridge | bridging part 62a of 2nd Embodiment. A covering member, for example, a rubber-covered molded portion 92 is interposed between the first metal separator 90 and the resin-made connecting portion 64a constituting the connecting bridge portion 62a. The rubber coating forming portion 92 is formed on the surface 90a of the first metal separator 90 integrally with the first seal member 30 or separately.

  As shown in FIG. 10, the 1st metal separator 100 which comprises the fuel cell stack which concerns on the 6th Embodiment of this invention provides the connection bridge | bridging part 72a of 3rd Embodiment. A covering member, for example, a rubber-covered molded part 102 is interposed between the first metal separator 100 and the resin-made connecting part 74a constituting the connecting bridge part 72a. The rubber covering molding portion 102 is molded on the surface 100a of the first metal separator 100 integrally with the first seal member 30 or separately.

  In the fourth to sixth embodiments configured as described above, the same effects as in the first to third embodiments can be obtained. Moreover, the rubber-coated molded parts 82, 92 and 102 can prevent the metal potential difference corrosion well and prevent the elution of metal ions.

  As shown in FIG. 11, the fuel cell 112 constituting the fuel cell stack 110 according to the seventh embodiment of the present invention has an electrolyte membrane / electrode structure 14 in the first metal separator 114 and the second metal separator 18. It is pinched.

  As shown in FIGS. 11 and 12, the first metal separator 114 is provided with a connection bridge portion 116a, and the connection bridge portion 116a includes a resin passage member 118a. A plurality of holes (openings) 120 are formed in the first metal separator 114, and the resin passage member 118a is integrally formed on both surfaces 114a and 114b of the first metal separator 114 via the holes 120. The A passage 122a is formed between the resin passage members 118a.

  A first seal member 124 is integrally formed on the outer peripheral edge of the first metal separator 114 over both surfaces 114a and 114b. The resin-made passage member 118a and the first seal member 124 are formed by overlapping a part of each other in the stacking direction (arrow A direction).

  In the seventh embodiment configured as described above, the resin-made passage member 118 a is integrally formed on both surfaces 114 a and 114 b of the first metal separator 114 via the hole 120. Accordingly, the resin passage member 118a and the first metal separator 114 can be more firmly and reliably integrated. Moreover, for example, when the resin material is supplied from one surface 114a, the rubber-covered molded portion 102 is supplied to the opposite surface 114b through the hole 120, so that the manufacturing is facilitated.

  Further, the resin passage member 118a and the first seal member 124 are formed by overlapping a part of each other in the stacking direction. For this reason, water does not enter from the gap between the resin-made passage member 118a and the first seal member 124, and the swelling of the first seal member 124 can be prevented as much as possible.

  In the first to seventh embodiments, the configuration in which the electrolyte membrane / electrode structure is sandwiched between two metal separators is adopted, but the present invention is not limited to this. For example, a power generation unit that includes three metal separators and two electrolyte membrane / electrode structures, and alternately stacks the metal separators and the electrolyte membrane / electrode structures, and uses a cooling medium between the power generation units. You may employ | adopt the fuel cell stack which forms a flow path and laminates | stacks the said electric power generation unit.

DESCRIPTION OF SYMBOLS 10,110 ... Fuel cell stack 12, 112 ... Fuel cell 14 ... Electrolyte membrane electrode assembly 16, 18, 60, 70, 80, 90, 100, 114 ... Metal separator 20a ... Oxidant gas inlet communication hole 20b ... Oxidation Agent gas outlet communication hole 22a ... Cooling medium inlet communication hole 22b ... Cooling medium outlet communication hole 24a ... Fuel gas inlet communication hole 24b ... Fuel gas outlet communication hole 26 ... Oxidant gas flow path 28a, 28b, 36a, 36b, 44a, 44b, 62a, 72a, 116a ... Connection bridge portion 29 ... Cooling medium flow path 30, 38, 124 ... Seal members 32a, 32b, 40a, 40b, 46a, 46b, 66a, 76a, 118a ... Resin passage members 33a, 33b , 42a, 42b, 48a, 48b, 68a, 78a, 122a ... passage 34 ... fuel gas passage 50 ... solid polymer battery Shitsumaku 52 ... anode 54 ... cathode 64a, 74a ... resin linking unit 82,92,102 ... rubber film forming unit 120 ... the hole

Claims (6)

An electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of the electrolyte and a metal separator are laminated, and at least a fluid that is any one of a fuel gas, an oxidant gas, or a cooling medium is disposed in the surface direction of the metal separator. A fuel cell stack in which a fluid flow path for flowing and a fluid communication hole for supplying the fluid in the stacking direction are formed,
The metal separator is provided with a connection bridge portion that communicates between the fluid flow path and the fluid communication hole,
The fuel cell stack, wherein the connection bridge portion includes a resin passage member provided integrally with the metal separator.   2. The fuel cell stack according to claim 1, wherein a covering member is interposed between the metal separator and the resin passage member.   3. The fuel cell stack according to claim 1, wherein the plurality of resin passage members are intermittently formed apart from each other on the metal separator. 4.   3. The fuel cell stack according to claim 1, wherein the plurality of resin passage members are continuously formed on the metal separator via a resin connection portion. 4.   2. The fuel cell stack according to claim 1, wherein the resin passage member is integrally formed on both surfaces of the metal separator through openings provided in the metal separator. The fuel cell stack according to claim 1 or 5, wherein a seal member is integrally formed on the metal separator,
The fuel cell stack, wherein the resin passage member and the seal member are formed by overlapping a part of each other in the stacking direction.

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