JP2023149965A - Separator for fuel cell and power generation cell - Google Patents

Abstract

To provide a separator for a fuel cell that is easy to manufacture.SOLUTION: A second separator 18 (separator for a fuel cell) of a power generation cell 10 includes a second separator body 72, and a porous member 74, and a groove-shaped oxidizing gas channel 76 is formed on the surface of the porous member 74 facing in the opposite direction from the second separator body 72. The oxidizing gas channel 76 has a plurality of branch portions 86 in which one linear channel 82 branches into two branch channels 84. The first angle θ1 formed by the two branch channels 84 branching from each of the plurality of branch portions 86 is smaller than 180°.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fuel cell separator and a power generation cell.

The power generation cell includes an electrolyte membrane/electrode assembly and a set of separators disposed on both sides of the electrolyte membrane/electrode assembly. The electrolyte membrane/electrode assembly includes an electrolyte membrane and a pair of electrodes disposed on both sides of the electrolyte membrane.

For example, Patent Document 1 discloses a separator in which a concave reactive gas channel is formed on the surface facing the electrode of a separator body in the form of a metal plate, and a plurality of protrusions made of a porous material are provided on the bottom surface of the reactive gas channel. (Separator for fuel cells) is disclosed.

Japanese Patent Application Publication No. 2010-129299

In the above-described fuel cell separator, it is necessary to attach a plurality of protrusions to the separator body, so there is a possibility that the fuel cell separator cannot be easily manufactured.

The present invention aims to solve the above-mentioned problems.

One aspect of the present invention is a fuel cell separator that is stacked on an electrolyte membrane/electrode assembly in which electrodes are provided on both sides of an electrolyte membrane, the separator comprising a plate-shaped separator body, and the electrode of the separator body. a porous member provided on a surface facing the separator body through which a reaction gas can flow, and a groove-shaped reaction gas flow path is formed on a surface of the porous member facing opposite to the separator body. , the reaction gas flow path has a plurality of branch portions in which one linear flow path branches into two branch flow paths, and the angle formed by the two branch flow paths branching from each of the plurality of branch portions. is a fuel cell separator whose angle is smaller than 180°.

Another aspect of the present invention is an electrolyte membrane/electrode assembly having an electrolyte membrane and a pair of electrodes disposed on both sides of the electrolyte membrane; The power generation cell includes a set of separators, one of which is the above-mentioned fuel cell separator.

According to the present invention, since the reactive gas flow path is formed in the porous member provided in the separator body, it is possible to easily manufacture a fuel cell separator. Further, the reaction gas flow path has a plurality of branch portions in which one linear flow path branches into two branch flow paths. Therefore, the reaction gas flowing through the linear channel hits a wall portion (branch wall portion) located between the two branch channels of the porous member, and thereby flows into two branch channels. At this time, the reaction gas flows through the inside of the branch wall portion, which is a part of the porous member, and is guided to the electrode. Therefore, the reaction gas can be efficiently supplied to the entire electrode. Furthermore, since the angle formed by the two branch channels branching from each of the plurality of branch parts is smaller than 180°, pressure loss of the reaction gas due to the branch wall part can be suppressed. Therefore, the reaction gas can be smoothly distributed downstream along the reaction gas flow path.

FIG. 1 is a partially omitted exploded perspective view of a fuel cell stack including a power generation cell according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a plan view of the porous member of FIG. 1.

As shown in FIG. 1, a plurality of power generation cells 10 according to an embodiment of the present invention are stacked in the thickness direction (direction of arrow A) to form a fuel cell stack 12. The fuel cell stack 12 is mounted, for example, on a fuel cell electric vehicle (not shown) as an on-vehicle fuel cell stack. Note that the direction in which the plurality of power generation cells 10 are stacked may be either the horizontal direction or the direction of gravity.

The power generation cell 10 is formed in a horizontally long rectangular shape. However, the power generation cell 10 may be formed in a vertically long rectangular shape. The power generation cell 10 includes an MEA member 14 (MEA: Membrane Electrode Assembly), a first separator 16, and a second separator 18 (fuel cell separator). The MEA member 14 includes an MEA 20 (electrolyte membrane/electrode assembly) and a resin frame member 22 (resin frame portion).

The first separator 16 is disposed on one surface of the MEA member 14 (the surface in the direction of arrow A1). The second separator 18 is disposed on the other surface of the MEA member 14 (the surface in the direction of arrow A2). The first separator 16 and the second separator 18 sandwich the MEA member 14 from the direction of arrow A.

The first separator 16 and the second separator 18 are bonded to each other by a plurality of bonding lines (not shown) to form a bonded separator 24. The first separator 16 and the second separator 18 are joined together by welding, brazing, caulking, or the like at their outer peripheries while being stacked on top of each other. The detailed structure of the first separator 16 and the second separator 18 will be described later.

In FIG. 2, the MEA 20 generates electricity through an electrochemical reaction between a fuel gas (one reaction gas) and an oxidant gas (the other reaction gas). MEA 20 includes an electrolyte membrane 26, an anode electrode 28, and a cathode electrode 30. The electrolyte membrane 26 is, for example, a solid polymer electrolyte membrane (cation exchange membrane). The solid polymer electrolyte membrane is, for example, a thin film of perfluorosulfonic acid containing water. For the electrolyte membrane 26, an HC (hydrocarbon) electrolyte can be used in addition to a fluorine electrolyte. The electrolyte membrane 26 is sandwiched between an anode electrode 28 and a cathode electrode 30.

The anode electrode 28 has a first electrode catalyst layer 32 and a first gas diffusion layer 34 . The first electrode catalyst layer 32 is joined to one surface 26a of the electrolyte membrane 26. The first gas diffusion layer 34 is stacked on the first electrode catalyst layer 32. The first electrode catalyst layer 32 includes, for example, porous carbon particles on which a platinum alloy is supported. The porous carbon particles are uniformly applied to the surface of the first gas diffusion layer 34 together with an ion-conductive polymer binder.

The cathode electrode 30 has a second electrode catalyst layer 36 and a second gas diffusion layer 38. The second electrode catalyst layer 36 is joined to the other surface 26b of the electrolyte membrane 26. The second gas diffusion layer 38 is laminated on the second electrode catalyst layer 36. The second electrode catalyst layer 36 includes, for example, porous carbon particles on which a platinum alloy is supported. The porous carbon particles are uniformly applied to the surface of the second gas diffusion layer 38 together with an ion-conductive polymer binder. Each of the first gas diffusion layer 34 and the second gas diffusion layer 38 is made of carbon paper, carbon cloth, or the like.

As shown in FIG. 1, the resin frame member 22 is a frame-shaped sheet surrounding the outer periphery of the MEA 20. As shown in FIG. The resin frame member 22 has electrical insulation properties. Examples of the constituent materials of the resin frame member 22 include PPS (polyphenylene sulfide), PPA (polyphthalamide), PEN (polyethylene naphthalate), PES (polyether sulfone), LCP (liquid crystal polymer), and PVDF (polyfluorofluoride). Examples include vinylidene chloride), silicone resin, fluororesin, m-PPE (modified polyphenylene ether resin), PET (polyethylene terephthalate), PBT (polybutylene terephthalate), and modified polyolefin.

An oxidant gas supply communication hole 40a, a coolant supply communication hole 42a, and a fuel gas discharge communication hole 44b are provided at one end edge in the long side direction of the power generation cell 10 (the edge in the direction of arrow B1). The oxidant gas supply communication hole 40a, the coolant supply communication hole 42a, and the fuel gas discharge communication hole 44b are arranged in the short side direction (arrow C direction) of the power generation cell 10.

Oxidizing gas (for example, oxygen-containing gas) flows through the oxidizing gas supply communication hole 40a in the direction of arrow A2. A cooling medium (for example, pure water, ethylene glycol, oil, etc.) flows through the cooling medium supply communication hole 42a in the direction of arrow A2. Fuel gas (for example, hydrogen-containing gas) flows through the fuel gas discharge communication hole 44b in the direction of arrow A1.

A fuel gas supply communication hole 44a, a coolant discharge communication hole 42b, and an oxidant gas discharge communication hole 40b are provided at the other edge in the long side direction of the power generation cell 10 (the edge in the direction of arrow B2). . The fuel gas supply communication hole 44a, the coolant discharge communication hole 42b, and the oxidant gas discharge communication hole 40b are arranged in the direction of arrow C.

Fuel gas flows through the fuel gas supply communication hole 44a in the direction of arrow A2. A cooling medium (refrigerant) flows through the cooling medium discharge communication hole 42b in the direction of arrow A1. Oxidant gas flows through the oxidant gas discharge communication hole 40b in the direction of arrow A1.

The arrangement, shape, and size of the communication holes (oxidant gas supply communication hole 40a, etc.) described above are not limited to the present embodiment, and may be appropriately set according to the required specifications.

As shown in FIGS. 1 and 2, the first separator 16 includes a plate-shaped first separator body 46. As shown in FIGS. The first separator body 46 is, for example, a thin metal plate such as a steel plate, a stainless steel plate, or an aluminum plate. The first separator body 46 may be subjected to anti-corrosion surface treatment. The first separator body 46 is formed in a rectangular shape.

A fuel gas flow path 48 extending in the long side direction (direction of arrow B) of the power generation cell 10 is provided on the surface of the first separator body 46 facing the MEA member 14 (hereinafter referred to as "surface 46a"). . The fuel gas passage 48 fluidly communicates with the fuel gas supply communication hole 44a and the fuel gas discharge communication hole 44b. The fuel gas flow path 48 supplies fuel gas to the anode electrode 28.

The fuel gas passage 48 has a plurality of passage grooves 52 formed between a plurality of passage protrusions 50 extending in the direction of arrow B. That is, in the fuel gas flow path 48, the flow path protrusions 50 and the flow path grooves 52 are arranged alternately in the flow path width direction (arrow C direction). The plurality of channel protrusions 50 and the plurality of channel grooves 52 are integrally provided in the first separator main body 46 by press molding. The channel protrusion 50 and the channel groove 52 extend linearly in the direction of arrow B. However, the channel protrusion 50 and the channel groove 52 may extend in the direction of the arrow B in a wavy manner.

In FIG. 1, a first seal portion 62 is provided on the surface 46a of the first separator body 46 to prevent leakage of a reactant gas (oxidant gas or fuel gas) or a fluid that is a cooling medium. The first seal portion 62 extends linearly when viewed from the separator thickness direction (arrow A direction). However, the first seal portion 62 may extend in a wavy shape when viewed from the separator thickness direction (stacking direction).

The first seal portion 62 is formed into a trapezoidal or rectangular cross section by press-molding the first separator body 46. However, the first seal portion 62 may be a rubber seal. The first seal portion 62 includes a plurality of first communication hole seal portions 64 and a first flow path seal portion 66 . The plurality of first communication hole seal parts 64 individually surround the plurality of communication holes (oxidizing gas supply communication hole 40a, etc.). The first flow path seal portion 66 is provided on the outer periphery of the first separator body 46 .

A first supply bridge 68 for guiding the fuel gas from the fuel gas supply communication hole 44a to the fuel gas flow path 48 is provided in the first flow path seal portion 66 surrounding the fuel gas supply communication hole 44a. A first exhaust bridge 70 for guiding the fuel gas flowing through the fuel gas passage 48 to the fuel gas exhaust passage 44b is provided in the first passage sealing portion 66 surrounding the fuel gas exhaust passage 44b.

The second separator 18 includes a plate-shaped second separator main body 72 and a porous member 74. The second separator body 72 is, for example, a thin metal plate such as a steel plate, a stainless steel plate, or an aluminum plate. The second separator main body 72 may be subjected to anti-corrosion surface treatment. The second separator main body 72 is formed in a rectangular shape.

The porous member 74 is joined to the surface of the second separator body 72 facing the cathode electrode 30 (hereinafter referred to as "surface 72a"). The porous member 74 is formed in a rectangular shape. Porous member 74 is formed of a metal material. The porous member 74 has a three-dimensional network structure. Oxidizing gas can flow through the porous member 74.

An oxidizing gas flow path 76 (reactive gas flow path) is formed on a surface 74a of the porous member 74 facing the cathode electrode 30 (a surface facing in the opposite direction to the first separator body 46). The oxidant gas passage 76 fluidly communicates with the oxidant gas supply communication hole 40a and the oxidant gas discharge communication hole 40b. The oxidizing gas flow path 76 supplies oxidizing gas to the cathode electrode 30 .

The oxidant gas flow path 76 extends from one end (end in the direction of arrow B1) to the other end (end in the direction of arrow B2) of the porous member 74. In FIG. 2, the oxidizing gas flow path 76 is a groove with a rectangular cross section. The groove bottom surface 76a of the oxidizing gas flow path 76 is formed by the porous member 74. In other words, the groove depth of the oxidizing gas flow path 76 is shallower than the thickness of the porous member 74. The oxidant gas flow path 76 is integrally provided in the porous member 74 by, for example, press molding.

As shown in FIG. 3, the oxidant gas flow path 76 is formed in a honeycomb shape when viewed from above in the thickness direction of the porous member 74 (as viewed from the direction of arrow A1). That is, the oxidant gas flow path 76 is formed by connecting a plurality of hexagonal polygonal flow path portions 78 to each other when viewed from above in the thickness direction of the porous member 74.

In other words, the portion of the porous member 74 surrounded by the polygonal channel portion 78 forms a hexagonal polygonal portion 80 when viewed from above in the thickness direction of the porous member 74 . The polygonal section 80 has a shape corresponding to the shape of the polygonal flow path section 78. The polygonal portion 80 contacts or is close to the cathode electrode 30 (see FIG. 2).

In this embodiment, the polygonal flow path portion 78 is formed in a regular hexagonal shape. However, the polygonal flow path portion 78 is not limited to a regular hexagonal shape, and may be formed in a hexagonal shape other than a regular hexagonal shape. Further, the polygonal flow path section 78 may be formed in a polygonal shape other than a hexagonal shape, such as a triangular shape, a quadrangular shape, or a pentagonal shape.

The oxidant gas flow path 76 includes a plurality of linear flow paths 82 , a plurality of branch flow paths 84 , a plurality of branch portions 86 , and a plurality of merging portions 88 . Each branch portion 86 is a portion where one linear channel 82 branches into two branch channels 84 . The plurality of branch parts 86 have a first branch part 86a and a second branch part 86b. The first branch portion 86a and the second branch portion 86b are arranged alternately at intervals in a direction (direction of arrow C) orthogonal to the flow direction of the oxidant gas in the oxidant gas flow path 76 (direction of arrow B2). There is. Note that the direction of flow of the oxidant gas is the direction from one end of the second separator body 72 to the other end. In other words, the flow direction of the oxidant gas is the direction from the inlet end to the outlet end of the oxidant gas flow path 76.

In the merging section 88, one of the two branch channels 84 branched from the first branch section 86a and one of the two branch channels 84 branched from the second branch section 86b are connected to the first branch section 86a. and a portion that merges into one linear flow path 82 of a branch portion 86 located downstream of the second branch portion 86b. The plurality of branch portions 86 and the plurality of merging portions 88 are alternately arranged toward the downstream of the oxidant gas flow path 76.

Each polygonal flow path portion 78 includes three branch portions 86 and three merging portions 88. The three branch parts 86 and the three merging parts 88 are located at the vertices (hexagonal vertices) of the polygonal flow path part 78. Further, each polygonal flow path section 78 includes four branch flow paths 84 and two linear flow paths 82. A corner located on the most upstream side (arrow B1 direction) of each polygonal part 80 forms a branch wall part 90 located between the two branch channels 84. The branch wall portion 90 is located on an extension of the linear flow path 82.

In each branch portion 86, the first angle θ1 formed by the two branch channels 84 (the angle of the branch wall portion 90) is smaller than 180°. In each merging portion 88, a second angle θ2 between the linear flow path 82 and the branch flow path 84 branched from the first branch portion 86a is smaller than 180°. Further, in each merging portion 88, a third angle θ3 formed between the branch flow path 84 branched from the second branch portion 86b and the linear flow path 82 is smaller than 180°. Specifically, each of the first angle θ1, the second angle θ2, and the third angle θ3 is 120°.

In FIG. 1, a second seal portion 92 is provided on the surface 72a of the second separator body 72 to prevent leakage of a reactant gas (oxidant gas or fuel gas) or a fluid that is a cooling medium. The second seal portion 92 extends linearly when viewed from the separator thickness direction (arrow A direction). However, the second seal portion 92 may extend in a wavy shape when viewed from the separator thickness direction (stacking direction).

The second seal portion 92 has a trapezoidal or rectangular cross section by press-molding the second separator main body 72. However, the second seal portion 92 may be a rubber seal. The second seal portion 92 includes a plurality of second communication hole seal portions 94 and a second passage seal portion 96 . The plurality of second communication hole seal portions 94 individually surround the plurality of communication holes (oxidant gas supply communication hole 40a, etc.). The second flow path seal portion 96 is provided on the outer periphery of the first separator body 46.

A second supply bridge 98 for guiding the oxidant gas from the oxidant gas supply communication hole 40 a to the oxidant gas flow path 76 is provided in the second passage seal portion 96 surrounding the oxidant gas supply communication hole 40 a. A second exhaust bridge 100 for guiding the oxidizing gas that has passed through the oxidizing gas flow path 76 to the oxidizing gas exhausting hole 40b is provided in the second passage sealing portion 96 surrounding the oxidizing gas exhaust passage 40b. It will be done.

Between the surface 46b of the first separator main body 46 and the surface 72b of the second separator main body 72, which are joined to each other, there is a cooling medium flow that fluidly communicates with the cooling medium supply communication hole 42a and the coolant discharge communication hole 42b. A channel 102 is formed.

The power generation cell 10 configured in this manner operates as follows.

First, as shown in FIG. 1, fuel gas is supplied to the fuel gas supply communication hole 44a. The oxidizing gas is supplied to the oxidizing gas supply communication hole 40a. The cooling medium is supplied to the cooling medium supply communication hole 42a.

The fuel gas is introduced into the fuel gas passage 48 of the first separator 16 from the fuel gas supply communication hole 44a via the first supply bridge 68. The fuel gas is supplied to the anode electrode 28 of the MEA 20 while flowing through the fuel gas passage 48 in the direction of arrow B1.

On the other hand, the oxidizing gas is introduced from the oxidizing gas supply communication hole 40a to the oxidizing gas passage 76 of the second separator 18 via the second supply bridge 98. The oxidizing gas introduced into the oxidizing gas flow path 76 flows into the plurality of linear flow paths 82 .

As shown in FIG. 3, the oxidizing gas introduced into the linear channel 82 hits the branch wall 90 at the branch section 86 (the first branch section 86a and the second branch section 86b), thereby forming two branch channels. 84. Subsequently, the oxidant gas branched from the first branch part 86a and the oxidant gas branched from the second branch part 86b merge into the linear flow path 82 at the merging part 88. That is, the oxidant gas alternately flows through the linear flow path 82 and the branch flow path 84 toward the downstream of the oxidant gas flow path 76 (in the direction of arrow B2). In other words, the oxidizing gas alternately flows through the branching portion 86 and the merging portion 88 toward the downstream of the oxidizing gas flow path 76 (in the direction of arrow B2). The oxidant gas is supplied to the cathode electrode 30 of the MEA 20 while flowing in the oxidant gas flow path 76 in the direction of arrow B2.

Further, the oxidant gas flows into the polygonal section 80 from the branch wall section 90 of the porous member 74 at the branch section 86 . The oxidizing gas that has flowed into the polygonal section 80 is supplied to the cathode electrode 30 while flowing inside the polygonal section 80 . Thereby, the oxidant gas is uniformly supplied to the entire cathode electrode 30.

Therefore, in the MEA 20, the fuel gas supplied to the anode electrode 28 and the oxidant gas supplied to the cathode electrode 30 are consumed by electrochemical reactions within the first electrode catalyst layer 32 and the second electrode catalyst layer 36. Ru. As a result, power is generated. At this time, protons are generated at the anode electrode 28, and these protons pass through the electrolyte membrane 26 and move to the cathode electrode 30. On the other hand, at the cathode electrode 30, water is generated by protons, electrons, and oxygen in the oxidant gas.

Next, the partially consumed fuel gas supplied to the anode electrode 28 is discharged as fuel off-gas from the fuel gas passage 48 via the first discharge bridge 70 to the fuel gas discharge communication hole 44b. The oxidizing gas consumed by the cathode electrode 30 is discharged as oxidizing off-gas from the oxidizing gas passage 76 through the second exhaust bridge 100 to the oxidizing gas exhaust communication hole 40b.

Furthermore, water generated at the cathode electrode 30 (produced water) is discharged together with the oxidant off-gas. Specifically, the generated water in the portion of the cathode electrode 30 facing the oxidant gas flow path 76 flows directly from the cathode electrode 30 to the oxidant gas flow path 76 . On the other hand, the generated water in the portion of the cathode electrode 30 facing the polygonal section 80 of the porous member 74 passes through the inside of the polygonal section 80 and is guided to the oxidizing gas channel 76 . Thereby, it is possible to suppress the generated water from remaining in a part of the cathode electrode 30.

The coolant supplied to the coolant supply communication hole 42a is introduced into the coolant flow path 102 formed between the first separator 16 and the second separator 18. The cooling medium flows in the direction of arrow B after being introduced into the cooling medium flow path 102. After cooling the MEA 20, this cooling medium is discharged from the cooling medium discharge communication hole 42b.

This embodiment has the following effects.

According to this embodiment, since the oxidant gas flow path 76 is formed in the porous member 74 provided in the second separator main body 72, the second separator 18 can be manufactured easily. Further, the oxidant gas flow path 76 has a plurality of branch portions 86 in which one linear flow path 82 branches into two branch flow paths 84 . Therefore, the oxidizing gas flowing through the linear flow path 82 hits the wall portion (branch wall portion 90) located between the two branch flow paths 84 of the porous member 74, so that the oxidant gas flows through the two branch flow paths 84. It flows in two parts. At this time, the oxidizing gas flows through the inside of the branch wall portion 90 (inside the polygonal portion 80 ) that is a part of the porous member 74 and is guided to the cathode electrode 30 . Therefore, the oxidant gas can be efficiently supplied to the entire cathode electrode 30. Furthermore, since the first angle θ1 formed by the two branch channels 84 branching from each of the plurality of branch portions 86 is smaller than 180°, pressure loss of the oxidant gas due to the branch wall portion 90 can be suppressed. Therefore, the oxidizing gas can be smoothly circulated downstream along the oxidizing gas flow path 76.

The groove bottom surface 76a of the oxidizing gas flow path 76 is formed by the porous member 74.

According to such a configuration, the second separator 18 can be manufactured even more easily.

The plurality of branch portions 86 include a first branch portion 86 a and a second branch portion 86 b that are arranged in parallel in a direction perpendicular to the flow direction of the oxidant gas in the oxidant gas flow path 76 . In the oxidizing gas flow path 76, one of the two branch flow paths 84 branched from the first branch portion 86a and one of the two branch flow paths 84 branched from the second branch portion 86b are connected to the second branch portion 86b. It has a plurality of merging portions 88 that merge into one linear flow path 82 of the branching portion 86 located downstream of the first branching portion 86a and the second branching portion 86b. In each of the plurality of merging sections 88, the angle between each of the two branch channels 84 and the one linear channel 82 (the second angle θ2 and the third angle θ3) is smaller than 180°.

According to such a configuration, the oxidizing gas can be more smoothly distributed downstream along the oxidizing gas flow path 76.

The plurality of branch portions 86 and the plurality of merging portions 88 are alternately arranged toward the downstream of the oxidant gas flow path 76.

According to such a configuration, the oxidant gas can be supplied to the entire cathode electrode 30 more efficiently.

The oxidizing gas flow path 76 is formed by connecting a plurality of hexagonal polygonal flow path portions 78 to each other in a plan view from the thickness direction of the porous member 74. The plurality of branch parts 86 and the plurality of merging parts 88 are located at the vertices of each of the plurality of polygonal flow path parts 78.

According to such a configuration, a plurality of branch portions 86 and a plurality of merging portions 88 can be alternately arranged toward the downstream side of the oxidant gas flow path 76 with a simple configuration.

Each of the plurality of polygonal flow path portions 78 is formed into a regular hexagonal shape when viewed from above in the thickness direction of the porous member 74.

According to such a configuration, the oxidizing gas can be more smoothly distributed downstream along the oxidizing gas flow path 76.

The porous member 74 has a three-dimensional network structure.

According to such a configuration, the oxidant gas that has flowed into the inside of the branch wall portion 90 can be efficiently guided to the cathode electrode 30.

Note that the present invention is not limited to the embodiments described above, and can take various configurations without departing from the gist of the present invention.

This embodiment discloses the following contents.

The above embodiment is a fuel cell separator (18) that is laminated on an electrolyte membrane/electrode assembly (20) in which electrodes (28, 30) are arranged on both sides of an electrolyte membrane (26), and is plate-shaped. a separator main body (72), and a porous member (74) provided on the surface (72a) of the separator main body facing the electrode and through which a reaction gas can flow; A groove-shaped reaction gas flow path (76) is formed on the surface (74a) facing in the opposite direction from the main body, and the reaction gas flow path has one linear flow path (82) divided into two branched flow paths. (84), the angle (θ1) formed by the two branch flow paths branching from each of the plurality of branch parts is smaller than 180°; A separator is disclosed.

In the fuel cell separator described above, the groove bottom surface (76a) of the reaction gas flow path may be formed of the porous member.

In the above fuel cell separator, the plurality of branch parts include a first branch part (86a) and a second branch part (86b) arranged in parallel in a direction perpendicular to the flow direction of the reaction gas in the reaction gas flow path. ), the reaction gas flow path includes one of the two branch flow paths branched from the first branch portion and one of the two branch flow paths branched from the second branch portion. has a plurality of merging parts (88) that merge with the one linear flow path of a branch part located downstream of the first branch part and the second branch part, and each of the plurality of merging parts In this case, the angles (θ2, θ3) between each of the two branch channels and the one linear channel may be smaller than 180°.

In the fuel cell separator described above, the plurality of branch parts and the plurality of merging parts may be arranged alternately toward the downstream of the reaction gas flow path.

In the fuel cell separator described above, the reaction gas flow path is formed by connecting a plurality of hexagonal polygonal flow path portions (78) to each other in a plan view from the thickness direction of the porous member; The plurality of branch parts and the plurality of merging parts may be located at the vertices of each of the plurality of polygonal flow path parts.

In the fuel cell separator described above, each of the plurality of polygonal flow path portions may be formed in a regular hexagonal shape in the plan view.

In the above fuel cell separator, the porous member may have a three-dimensional network structure.

The above embodiment includes an electrolyte membrane/electrode assembly having an electrolyte membrane and a pair of electrodes disposed on both sides of the electrolyte membrane, and a set of separators disposed on both sides of the electrolyte membrane/electrode assembly. (16, 18), and one side of the set of separators is the above-mentioned fuel cell separator.

10... Power generation cell 16... First separator 18... Second separator (fuel cell separator)
20... MEA (electrolyte membrane/electrode assembly) 26... Electrolyte membrane 28... Anode electrode 30... Cathode electrode 72... Second separator body (separator body)
74... Porous member 76... Oxidizing gas flow path (reactive gas flow path)
78... Polygonal flow path portion 82... Linear flow path 84... Branch flow path 86... Branch portion 86a... First branch portion 86b... Second branch portion 88... Merging portion θ1... First angle θ2... Second angle θ3...Third angle

Claims (8)

A fuel cell separator that is laminated on an electrolyte membrane/electrode structure in which electrodes are arranged on both sides of the electrolyte membrane,
A plate-shaped separator body,
a porous member provided on the surface of the separator body facing the electrode and through which a reactive gas can flow;
A groove-shaped reaction gas flow path is formed on a surface of the porous member facing in a direction opposite to the separator main body,
The reaction gas flow path has a plurality of branch parts where one linear flow path branches into two branch flow paths,
The separator for a fuel cell, wherein the angle formed by the two branch channels branching from each of the plurality of branch portions is smaller than 180°. The fuel cell separator according to claim 1,
A fuel cell separator, wherein the groove bottom surface of the reaction gas flow path is formed of the porous member. The fuel cell separator according to claim 1 or 2,
The plurality of branch parts include a first branch part and a second branch part arranged in parallel in a direction perpendicular to the flow direction of the reaction gas in the reaction gas flow path,
The reaction gas flow path is such that one of the two branch flow paths branched from the first branch portion and one of the two branch flow paths branched from the second branch portion are connected to the first branch flow path. A branch part and a plurality of merging parts that merge with the one linear flow path of a branch part located downstream of the second branch part,
In each of the plurality of merging sections, the angle between each of the two branch channels and the one linear channel is smaller than 180°. The fuel cell separator according to claim 3,
In the fuel cell separator, the plurality of branch parts and the plurality of merging parts are alternately arranged toward the downstream of the reaction gas flow path. The fuel cell separator according to claim 4,
The reaction gas flow path is formed by a plurality of hexagonal polygonal flow path portions connected to each other when viewed from above in the thickness direction of the porous member,
In the fuel cell separator, the plurality of branch parts and the plurality of merging parts are located at the vertices of each of the plurality of polygonal flow path parts. The fuel cell separator according to claim 5,
In the fuel cell separator, each of the plurality of polygonal flow path portions is formed in a regular hexagonal shape when viewed from above. The fuel cell separator according to any one of claims 1 to 6,
The porous member is a fuel cell separator having a three-dimensional network structure. an electrolyte membrane/electrode structure having an electrolyte membrane and a pair of electrodes disposed on both sides of the electrolyte membrane;
A power generation cell comprising a set of separators disposed on both sides of the electrolyte membrane/electrode structure,
A power generation cell, wherein one of the set of separators is a fuel cell separator according to any one of claims 1 to 7.

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