JP2002184431A - Fuel cell separator and fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide fuel cell separators having electrodes superior in gas diffusivity and to provide a fuel cell with superior power generating performance and durability. SOLUTION: The separators 4 and 5 are so positioned as oppositely abutting on a pair of electrodes 2 and 3 clamping a solid polymer electrolyte membrane 1 from both sides and gas channels 41 and 51 are provided on the opposite faces of the electrodes 2 and 3. The fuel cell separators 4 and 5 are characterized in that the angle on the side of the gas channels 41 and 51 formed by abutment faces 48a and 88a of the separators 4 and 5 abutting on the electrodes 2 and 3 and crossing faces 46d and 90 crossing with the abutment faces 48a and 88a of side faces 46a and 86a of the gas channels 41 and 51 is an acute angle. The fuel cell is characterized in that the fuel cell separators 4 and 5 clamp the pair of electrodes 2 and 3 clamping the solid polymer electrolyte membrane 1 from both side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In order to reduce air pollution as much as possible, it is important to take measures against exhaust gas from automobiles, and as one of the measures, electric vehicles are used. Has not been reached.

[0003] Fuel cells are attracting attention as clean power generation devices that generate hydrogen by the reverse reaction of electrolysis using hydrogen and oxygen and do not emit any waste other than water. It is considered to be a clean car with a certain quality. Among the fuel cells, solid polymer electrolyte fuel cells operate at low temperatures and are most promising for automobiles.

[0004] A solid polymer electrolyte fuel cell generally has a large number of single cells stacked, and the single cell is joined with a solid polymer electrolyte membrane sandwiched between two electrodes (a fuel electrode and an oxidant electrode). The joined body of the solid polymer electrolyte membrane and the electrode is sandwiched between separators having a gas flow path for a fuel gas or an oxidizing gas.

[0005] As a role of the separator, it is important to have a structure that can sufficiently bring out the performance of a membrane-electrode assembly (hereinafter referred to as MEA). As one of them, there is a role to supply gas uniformly to the entire surface of the gas diffusion layer constituting the MEA. For that purpose, as described below, it is necessary that water clogging does not occur in the gas flow path and the diffusion layer of the separator.

FIG. 6 is a schematic sectional view of a general single cell of a solid polymer electrolyte fuel cell. A solid polymer electrolyte fuel cell uses a solid polymer electrolyte membrane 101 as an electrolyte. The MEA 110 is joined with the solid polymer electrolyte membrane 101 sandwiched between the oxidant electrode 102 and the fuel electrode 103. The oxidizer electrode 102 and the fuel electrode 103 are configured by laminating catalyst layers 102b and 103b on gas diffusion current collectors (diffusion layers) 102a and 103a, respectively, and the respective catalyst layers 102b and 103b are formed of a solid polymer electrolyte membrane 101. Facing the side.

[0007] The MEA 110 is sandwiched between the separator 104 and the separator 105 to constitute a single cell of a solid polymer electrolyte fuel cell. A fuel cell has a large number of single cells of this solid polymer electrolyte fuel cell. The oxidizing gas flow path 1 through which the oxidizing gas flows
04a is provided. The separator 105 is provided with a fuel gas passage 105a through which the fuel gas flows. The oxidizing gas is an oxygen-containing gas such as air. As the fuel gas, a hydrogen-containing gas, such as a reformed gas obtained by reforming a hydrocarbon-based fuel such as methanol or gasoline into a gas containing hydrogen, pure hydrogen, or the like is used. The oxidizing gas and the fuel gas contain water vapor for humidifying the solid polymer electrolyte membrane 101.

[0008] At the fuel electrode 103, the reaction of the formula (1) occurs. 2H ₂ → 4H ⁺ + 4e ⁻ (1) The proton H ⁺ generated at the fuel electrode 103 moves toward the oxidant electrode 102 through the solid polymer electrolyte membrane 101, and at the same time, the fuel electrode 103 Electron e ⁻ generated by
Moves to the oxidizer electrode 4 through the separator 105, the load connected between the fuel electrode 103 and the oxidizer electrode 102, and the separator 104.

On the other hand, at the oxidant electrode 4, oxygen is reduced by the reaction of the formula (2), and combines with the protons H ⁺ transferred from the fuel electrode 103 to form water. O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (2) Part of the generated water enters the solid polymer electrolyte membrane 101 due to the concentration gradient, and diffuses and moves toward the fuel electrode 103. The part evaporates and is discharged with unreacted oxidant gas. The reactions of the above formulas (1) and (2) both occur on the three-phase interface where the three members of the electrode constituent material, the electrolyte (electrolyte), and the gas, which are electronic conductors, come into contact.

In order for the reactions of the above equations (1) and (2) to proceed, the fuel gas and the oxidizing gas that have passed through the gas diffusion current collectors 102a and 103a are sufficiently supplied to the catalyst layers 102b and 103b. It is necessary to For this purpose, water vapor in the oxidizing gas and the fuel gas is supplied to the gas diffusion current collector 102.
It is important that no agglomeration occurs at a and 103a, and that water generated by the reaction of the formula (2) at the oxidant electrode 4 does not remain at the gas diffusion current collector 102a.

Therefore, the gas diffusion current collectors 102a,
3a is made to have water repellency, or the gas diffusion current collector 102a,
In general, coagulation of water is prevented by adjusting the pore diameter of 103a. However, for example, under operating conditions in a high current range, the coagulated water is
The phenomenon that the gas supply to the catalyst layer 102b is interrupted due to staying at a, that is, so-called flooding occurs, and a measure for ensuring gas diffusibility is not sufficient.

As a prior art, Japanese Patent Application Laid-Open No. 10-17258
Patent Document 6 discloses a fuel cell in which a water-absorbing member that changes the cross-sectional area of the flow path according to the amount of water absorption is provided in a part of the flow path.

[0013]

However, the prior art is effective in preventing water clogging in the gas flow path of the separator, but reduces the water clogging in the gas diffusion current collector near the contact portion with the separator. And there was a problem that gas diffusivity was insufficient.

The present invention has solved the above-mentioned problems, and provides a fuel cell separator having excellent electrode gas diffusion properties and a fuel cell having excellent power generation performance and durability.

[0015]

Means for Solving the Problems In order to solve the above technical problems, the technical means (hereinafter referred to as first technical means) taken in claim 1 of the present invention is a solid polymer electrolyte. A separator provided with a gas flow path on a surface facing the pair of electrodes sandwiching the membrane from both sides, and a contact surface of the separator with the electrode, The fuel cell separator according to claim 1, wherein an angle between a side surface of the gas flow path and an intersecting surface intersecting with the contact surface on the gas flow path side is an acute angle.

The effects of the first technical means are as follows.

That is, since the angle on the gas flow path side formed by the contact surface of the separator with the electrode and the crossing surface of the gas flow path that intersects with the contact surface is acute, the electrode on the gas flow path side surface is The shearing force applied to the electrode by the contacting corner can be reduced. As a result, the member forming the gas diffusion layer of the electrode is cut, and the formation of a new surface having no water repellency is suppressed, so that the aggregation of water at the corners can be reduced, and the gas diffusion property of the electrode can be reduced. An excellent fuel cell separator can be obtained.

Further, since the angle between the contact surface of the separator with the electrode and the crossing surface of the side surface of the gas flow passage that intersects with the contact surface is acute, the contact area between the separator and the electrode is small. And the aggregation of water at the contact surface can be reduced, and a fuel cell separator having excellent electrode gas diffusion properties can be obtained.

In order to solve the above technical problem, the technical means (hereinafter referred to as the second technical means) taken in claim 2 of the present invention is such that the gas flow path faces the electrode. 2. A contact portion having a width increasing toward the electrode, and a base portion continuing from the contact portion and located on a side opposite to the electrode and having substantially the same width. Fuel cell separator.

The effects of the second technical means are as follows.

That is, since the gas flow path is widened toward the electrode and is in contact therewith, the corner portion of the gas flow path which is in contact with the electrode alleviates the shearing force applied to the electrode. Thus, the aggregation of water at the corners can be reduced, and a fuel cell separator having excellent electrode gas diffusion properties can be obtained.

Further, since the gas flow path is widened toward the electrode and is in contact therewith, the contact area of the separator with the electrode can be reduced, and the aggregation of water on the contact surface can be reduced. Thus, a fuel cell separator having excellent electrode gas diffusion properties can be obtained.

In order to solve the above technical problem, the technical means (hereinafter referred to as third technical means) taken in claim 3 of the present invention is a gas flow direction on the side surface of the contact portion. 3. The fuel cell separator according to claim 2, wherein a cross-sectional shape perpendicular to the shape is convex toward the electrode.

The effects of the third technical means are as follows.

That is, since the cross-sectional shape of the side surface of the contact portion perpendicular to the gas flow direction is convex toward the electrode,
This curvature makes it difficult for water to stay at the corner of the gas channel side that abuts on the electrode, and also alleviates the shearing force applied to the electrode, reduces water aggregation at the corner, and reduces the A fuel cell separator having excellent gas diffusion properties can be obtained.

In order to solve the above technical problem, the technical means (hereinafter referred to as fourth technical means) taken in claim 4 of the present invention is described in any one of claims 1 to 3. And a pair of electrodes for sandwiching the solid polymer electrolyte membrane from both sides.

The effects of the fourth technical means are as follows.

That is, since a fuel cell separator having excellent electrode gas diffusion properties is used, a fuel cell having excellent power generation performance and durability can be manufactured.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventor has analyzed the cause of the occurrence of water clogging, and has conducted intensive research to eliminate the cause, leading to the present invention. FIG. 7 is an explanatory diagram for explaining the cause of water clogging. FIG. 7 is an enlarged partial cross-sectional view of the contact portion between the electrode 102 and the separator 104. The gas flow path 104 a side of the separator 104 is in contact with the electrode 102. Electrode 1
In reference numeral 02, a catalyst layer 102b is laminated on a gas diffusion current collector (diffusion layer) 102a. The gas diffusion current collector 102 a side of the electrode 102 is in contact with the separator 104.

The portion where water easily aggregates is the separator 1
04 and the gas diffusion current collector 102a. If water agglomeration occurs at the contact portion of the gas diffusion current collector 102a with the separator 104, the gas cannot diffuse at the portion of the gas diffusion current collector 102a where the coagulated water exists.
Sufficient gas is not supplied to 2b. In addition, the water agglomeration tends to cause a decrease in the water repellency of the gas diffusion current collector 102a due to the aggregation of water, and a vicious cycle occurs in which the aggregation of the water easily occurs. Therefore, the gas diffusion current collector 102a
When water agglomerates in the inside, it is necessary that the agglomerated water be quickly discharged to the outside of the gas diffusion current collector 102a.

The separator 104 and the gas diffusion current collector 102
As a cause that water is likely to coagulate in the contact portion of a,
A shear force is applied to the gas diffusion current collector 102a by the corner of the convex portion 104b of the separator 104, and the carbon fibers and the like of the gas diffusion current collector 102a subjected to the water-repellent treatment buckle, and a new surface not subjected to the water-repellent treatment is exposed. It is conceivable that water agglomeration easily occurs. Another cause is
When the separator 104 is hydrophilic, the separator 104 at the contact portion between the separator 104 and the gas diffusion current collector 102a is used.
It is considered that aggregation of water is likely to occur near the surface.

Based on the above considerations, the present inventor has determined that the corner of the convex portion 104b of the separator 104 is
by providing a means for reducing the shearing force applied to a.
The aggregation of water at the contact portion between the separator 104 and the gas diffusion current collector 102a was reduced, and the gas diffusion property of the separator was improved. In addition, the present inventor reduces the contact area between the separator 104 and the gas diffusion current collector 102a, thereby reducing the aggregation of water at the contact portion between the separator 104 and the gas diffusion current collector 102a and improving the gas diffusivity of the separator. Was. Furthermore, the present inventor has improved the power generation performance and durability of the fuel cell by manufacturing a fuel cell using such a separator.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of a single cell of a solid polymer electrolyte fuel cell according to an embodiment. As in FIG.
A (membrane-electrode assembly) 10 is joined in a state where the solid polymer electrolyte membrane 1 is sandwiched between the oxidant electrode 2 and the fuel electrode 3. The oxidizer electrode 2 and the fuel electrode 3 are configured by laminating catalyst layers 21 and 31 on gas diffusion current collectors 22 and 32, respectively, and the respective catalyst layers 21 and 31 face the solid polymer electrolyte membrane 1 side. ing. MEA 10 is divided into separator 4 and separator 5
To constitute a solid polymer electrolyte fuel cell unit cell.

The separator 4 is provided with an oxidizing gas passage 41 through which the oxidizing gas flows. The separator 5 is provided with a fuel gas passage 51 through which fuel gas flows. FIG. 2 is an explanatory front view of the separator 4. The oxidizing gas is discharged from the oxidizing gas supply manifold 42 to the oxidizing gas discharge manifold 43 through the oxidizing gas passage 41. FIG. 3 is an explanatory front view of the separator 5.
The fuel gas is discharged from the fuel gas supply manifold 52 to the fuel gas discharge manifold 53 through the fuel gas flow path 51.

(Embodiment) FIG. 4 is a partially sectional explanatory view for explaining the structure of a gas flow channel of the embodiment. Although FIG. 4 illustrates the oxidizing gas channel, the fuel gas channel has the same structure. The oxidant gas flow path 41 has a concave shape and includes a base 45 having the same width (1 mm in width) and a contact portion 46 having a width increasing toward the oxidant electrode 2. The contact portion 46 faces and contacts the oxidant electrode 2. The base 45 is continuous with the contact portion 46 and is located on the side opposite to the oxidant electrode 2.

There is a projection 48 between the oxidizing gas channels 41 adjacent to each other. The top surface of each projection 48 is on the same plane, and forms a contact surface 48a that contacts the oxidant electrode 2. The cross section of each projection 48 has the same shape, and the height 1
mm, the width is 1 mm, and the corner 49 is 0.2 mm in radius.
R surface shape.

That is, the cross-sectional shape of the side surface 46 a of the contact portion 46 swells in a convex shape toward the oxidant electrode 2. The intersection surface 46b where this side surface 46a intersects with the contact surface 48a coincides with the contact surface 48a, and the intersection surface 4a and the intersection surface 4a
The angle of 6b on the oxidant gas flow path 41 side is 0 degree.

The oxidizer electrode and the fuel electrode used in the examples were manufactured as follows. Commercially available carbon paper (made by Toray Industries,
TGP-H-060) as a polytetrafluoroethylene (hereinafter abbreviated as PTFE) particle dispersion (manufactured by Daikin Industries, Ltd.)
D-1 grade, containing 60 wt% of PTFE particles) is immersed for 1 minute in a polytetrafluoroethylene particle dilute solution diluted with water so that the polytetrafluoroethylene particle concentration becomes 15 wt%, and then dried at about 80 ° C. Let
It was kept at 390 ° C. in the air for 60 minutes to perform a water-repellent treatment.

Next, carbon black fine particles (XC72-R, manufactured by Cabot Corporation, average particle size of about 30 nm), ethylene glycol and isopropyl alcohol are mixed to form a paste. This paste is applied on the water-repellent treated carbon paper by a screen printing method,
Dry at about 80 ° C. for 1 hour to form a conductive porous layer.
The carbon paper on which the conductive porous layer is formed is
The carbon paper was treated for water repellency in the same manner as the method for treating the water repellency. This is a gas diffusion current collector.

Platinum-supported carbon (40 wt.% Platinum content)
%), Water, an ion-exchange resin solution (Aciplex solution SS-1080, manufactured by Asahi Kasei Corporation) and isopropyl alcohol to prepare a catalyst paste, and the surface of the gas diffusion current collector printed with carbon black. Above, about 0.5 mg / c as platinum amount by doctor blade method
m ² and dried to form a catalyst layer on the gas diffusion current collector. The catalyst layer formed on the gas diffusion current collector was used as an oxidizer electrode and a fuel electrode.

The oxidizer electrode 2 and the fuel electrode 3 thus manufactured are connected to the solid polymer electrolyte membrane 1 (Nafion 11 manufactured by DuPont).
2) was sandwiched and joined by hot pressing under the conditions of 160 ° C. and 4 MPa to produce MEA 10. This MEA1
0 was sandwiched between the separator 4 and the separator 5 to produce a single fuel cell.

The evaluation was performed based on the output characteristics of a single fuel cell. Air of 0.25 MPa was supplied to the oxidant gas flow path 41 as an oxidant gas (utilization rate: 40%). Hydrogen of 0.25 MPa was supplied to the fuel gas flow path 51 as a fuel gas (utilization rate: 80%). At this time, both the oxidizing gas and the fuel gas were humidified by water. The humidifying amount of the oxidizing agent was 0.1 in molar ratio to the air gas amount, and the humidifying amount of the fuel was 0.3 in molar ratio to the pure hydrogen gas amount. A power generation test was performed with the cell temperature set to 80 ° C. and the current density changed from 0 A / cm ² to 1 A / cm ² . A durability test was performed at a current density of 0.5 A / cm ^{2 for} an operation time of 1000 h.

Comparative Example The comparative example has the same structure as the example except that the cross-sectional shape of the gas passage of the separator is different.
The manufacturing methods of the solid polymer electrolyte membrane, the oxidizer electrode, the fuel electrode, and the single cell of the fuel cell were the same, and the evaluation was performed by the same method.

FIG. 8 is a partial sectional view for explaining the structure of the gas flow channel of the embodiment. FIG. 8 illustrates the oxidizing gas channel, but the fuel gas channel has the same structure. The same reference numerals as in FIG. 6 were used. The oxidizing gas channel 104a has a concave shape having the same width (width 1 mm). According to the present invention, the base 1 having the same width (width 1 mm)
Abutment portion 104d having the same width (width 1 mm) as 04c
It is composed of

There is a contact portion 104b between the oxidizing gas flow paths 104a adjacent to each other. The top surface of each contact portion 104b is on the same plane, and forms a contact surface 104e that contacts the oxidant electrode 102. The cross section of each contact portion 104b has the same shape, and is 1 mm in height and 1 mm in width.
The corner 104f has a right angle. Intersecting surface 104h where side surface 46a of contact portion 104d intersects contact surface 104e
Is equal to the side surface 104g, and the angle between the contact surface 104e and the intersection surface 104h on the oxidant gas flow path 104a side is 90 degrees.

(Evaluation Results) Table 1 shows the power generation test results of the example and the comparative example. Current density 0.2, 1.0, 1.5 A /
The output voltage at cm ² is shown. The example has higher power generation performance in the high current region (1.0, 1.5 A / cm ² ) than the comparative example. This indicates that aggregation of water is less likely to occur in the example.

[0047]

[Table 1] Table 2 shows the durability test results of the examples and the comparative examples. The output voltage at the beginning of the durability test (0 h) and at 0.5 A / cm ² after 1000 hours of operation are shown. In the example, the rate of decrease in the output voltage is smaller than in the comparative example (Example 0.7%, Comparative Example 1.2%).

[0048]

[Table 2] After the durability test, the separator 4 and the separator 5 were removed, and the MEA 10 was taken out. After making the electrode surface of the MEA 10 in contact with the separator 4 or the separator 5 horizontal, watering the electrode surface, the electrode surface was vertical, and the state of water repellency was visually observed to evaluate the water repellency. .
Water remains in the portion where the water repellency is reduced. In the water repellency evaluation before the durability test, there was no portion where water remained on the electrode surface.

In the water repellency evaluation after the durability test, in both the comparative example and the example, water hardly dropped on the electrode surface in the contact portion with the separator (the contact portion with the convex portion of the separator), and the water repellency was lowered. Was. The portion where the water remains has a band shape corresponding to the convex portion of the separator.
The band-like width was measured. In the comparative example, the width at which the water repellency was reduced was 1 to 1.1 mm, which was slightly larger than the width of the contact between the separator and the electrode (the width of the convex portion 104b was 1 mm). On the other hand, in the example, the width of the reduced water repellency is 0.4 to 0.5 mm, which is slightly smaller than the width of the contact between the separator and the electrode (the width of the top surface of the projection 48 is 0.6 mm). I was It was confirmed that the water repellency of the example was less likely to decrease than the comparative example.

In the case of the separator of the comparative example, as shown in FIG. 7, water aggregates at the contact portion between the electrode and the separator and tends to stay. In particular, this is likely to occur when the material of the separator is hydrophilic. Because, when the separator is hydrophilic, when small water agglomerates on the separator surface at the contact portion between the electrode and the separator, the small agglomerated water wets the separator surface, and even if the gas diffuses to the vicinity, the coagulated water This is because they tend to remain on the separator surface.

At the corners of the convex portion 104b, a shearing force acts on the gas diffusion current collector by the separator, buckling occurs, and a new surface of carbon fiber is exposed. Since the new surface of the carbon fiber has not been subjected to the water-repellent treatment, water aggregation is likely to occur. As a result, water agglomerates at the contact portion between the electrode and the separator, hinders gas diffusion in the gas diffusion current collector, and lowers the output voltage. Further, when the coagulated water stays at the same site, the water repellency applied to the gas diffusion current collector is reduced, and the water is more likely to coagulate. As a result, the durability of the battery performance (output voltage) is adversely affected, and the durability is reduced.

Further, at the corners of the projections 104b, the shearing force applied to the gas diffusion current collector by the separator lowers the elastic modulus of the carbon fibers of the gas diffusion current collector, causing creep of the gas diffusion current collector. As a result, the contact resistance during long-time operation increased, resulting in a decrease in durability.

On the other hand, in the case of the separator of the embodiment, the protrusion 4
Due to the curvature given to the corner of No. 8, water hardly stays at the corner, and no shearing force is applied to the carbon fiber, so that a new surface of the carbon fiber that has not been subjected to the water-repellent treatment does not easily appear. As a result, water clogging at the separator contact portion of the gas diffusion current collector is less likely to occur than in the comparative example. Is kept highly diffusible. Further, the coagulated water is less likely to stay at the same site, the water repellency of the diffusion layer is prevented from lowering, and the durability of the battery performance (output voltage) is improved.

Further, the shear force applied to the gas diffusion current collector by the separator near the corner of the convex portion 48 is reduced,
It is possible to prevent the elastic modulus of the carbon fibers of the gas diffusion current collector from lowering, make it difficult for the gas diffusion current collector to creep, and prevent an increase in contact resistance during long-time operation. Furthermore, since the contact area between the separator and the gas diffusion current collector is reduced, aggregation of water can be reduced even if the separator is hydrophilic.

FIG. 5 is a partial sectional view for explaining the structure of a gas flow channel according to a modification of the present invention. The gas flow path 81 has a concave shape, and includes a base 85 having the same width (1 mm in width) and a contact portion 86 which becomes wider toward the electrode. The contact portion 86 faces and contacts the electrode. Base 85
Is located on the opposite side of the electrode from the contact portion 86.

There is a projection 88 between the oxidizing gas channels 81 adjacent to each other. The top surface of each projection 88 is on the same plane and forms a contact surface 88a that contacts the electrode.
The cross section of each projection 88 has the same shape, a height of 1 mm,
The width is 1 mm, and the corner 89 has a C-plane shape of 0.2 mm. The side surface 86a of the contact portion 86 is a contact surface 88a.
The angle formed on the gas flow path 81 side by the intersection surface 90 intersecting with the contact surface 88a is 45 degrees.

Also in this case, the shearing force on the gas diffusion current collector due to the corner of the projection 88 can be reduced, and the contact area between the separator and the gas diffusion current collector can be reduced.
As a result, water clogging at the separator contact portion of the gas diffusion current collector is reduced, and a separator having excellent electrode gas diffusion properties and a fuel cell having excellent power generation performance and durability can be manufactured as in the examples.

[0058]

As described above, according to the present invention, a gas flow path is provided on a surface facing a pair of electrodes which sandwich a solid polymer electrolyte membrane from both sides. A separator, wherein the contact surface of the separator with the electrode and the gas flow path side formed by an intersection of the side surface of the gas flow path and the intersection surface intersecting with the contact surface are acute angles. A fuel cell separator comprising a pair of electrodes sandwiching a solid polymer electrolyte membrane from both sides of the fuel cell separator and the fuel cell separator, the fuel cell separator having excellent electrode gas diffusion properties A separator and a fuel cell having excellent power generation performance and durability can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a single cell of a solid polymer electrolyte fuel cell according to an embodiment.

FIG. 2 is an explanatory front view of a separator 4.

FIG. 3 is an explanatory front view of a separator 5;

FIG. 4 is a partial cross-sectional explanatory view illustrating the structure of a gas flow channel according to an embodiment.

FIG. 5 is a partial cross-sectional explanatory view illustrating a structure of a gas flow channel according to a modification of the present invention.

FIG. 6 is a schematic cross-sectional view of a general solid polymer electrolyte fuel cell single cell.

FIG. 7 is an explanatory diagram for explaining the cause of water clogging.

FIG. 8 is a partial cross-sectional explanatory view illustrating the structure of a gas flow channel according to an embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Solid polymer electrolyte membrane 2 ... Oxidizer electrode (electrode) 3 ... Fuel electrode (electrode) 4, 5 ... Separator 41 ... Oxidant gas flow path (gas flow path) 45, 85 ... Base 46, 86 ... Contact Part 46a, 86a ... Side surface 46b, 90 ... Intersecting surface 48a, 88a ... Contact surface 51 ... Fuel gas flow path (gas flow path)

Claims (4)

[Claims] 1. A separator having a gas flow path provided on a surface facing a pair of electrodes sandwiching a solid polymer electrolyte membrane from both sides and facing the electrodes. A fuel cell separator, wherein an angle between a contact surface with an electrode and an intersecting surface of the side surface of the gas flow path intersecting with the contact surface on the gas flow path side is an acute angle. 2. The gas flow path according to claim 1, wherein said gas flow path is opposed to said electrode, and has a width that is increased toward said electrode. The fuel cell separator according to claim 1, further comprising a base having a width. 3. The fuel cell separator according to claim 2, wherein a cross-sectional shape of the side surface of the contact portion orthogonal to a gas flow direction is convex toward the electrode. 4. A fuel cell comprising: a pair of fuel cell separators according to claim 1 with a pair of electrodes sandwiching a solid polymer electrolyte membrane from both sides.