JP3357310B2 - Fuel cell separator and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell separator mainly used as an electric vehicle or a small portable power supply. A gas diffusion electrode having a sandwich structure sandwiched between cathodes (cathode) is further sandwiched from both outer sides thereof, and a fuel gas flow path and an oxidizing gas flow path are formed between the anode and the cathode to constitute a fuel cell. And a method for producing the same for a fuel cell separator of a solid polymer type or the like in which a single cell is constituted.

[0002]

_2. Description of the Related Art In a fuel cell, a fuel gas containing hydrogen is supplied to an anode, and an oxidizing gas containing oxygen is supplied to a cathode, so that H ₂ → 2H ′ + 2e ′. (1) (1/2) O ₂ + 2H ′ + 2e ′ → H ₂ O (2) An electrochemical reaction represented by the following formula is shown. As a whole, H ₂ + (（) O ₂ → H ₂ O (3) The electrochemical reaction of the following formula proceeds, and the chemical energy of such a fuel is directly converted into electric energy, thereby exhibiting a predetermined battery performance.

[0003] As a separator for a polymer electrolyte fuel cell, which is a kind of fuel cell that generates energy as described above, the installation area of the fuel cell itself is reduced as much as possible.
It is required that the thickness of the separator be reduced in order to reduce the weight, and at the same time, sufficient mechanical strength (such as bending strength) is maintained even when the thickness is reduced, and the flow path of the fuel gas and the oxidizing gas is reduced. Is required to be formed with very high precision. More specifically, regarding thinning of the separator,
Specifically, it is desirable that the thickness of the separator is 2 mm or less, and the thickness of the flat plate portion other than the convex portion is 1.0 mm or less.
The reason why mechanical strength is required irrespective of the thickness of the separator is that hundreds of separators are stacked, and the fuel cells are assembled by tightening and fixing them. When a large clamping force acts on the flat plate portion other than the convex portion forming the gas flow path of each separator, or when the handling gas acts on the front and back surfaces of the separator, the gas pressure difference between the front and back surfaces may be any one of the front and back surfaces. This is to prevent the separator from being damaged, such as cracking, when strongly acting on the surface.

The reason why high precision molding of the gas flow path is required is that, if chipping or R occurs on the surface of the corner of the projection forming the gas flow path due to poor molding accuracy, the projection is formed. The contact performance with the electrode in contact with the electrode decreases, the electrical resistivity when the separator is stacked increases, and a short-circuit phenomenon in which the fuel gas flows between the adjacent flow grooves formed between the protrusions occurs, This is to avoid adversely affecting the electromotive force efficiency of the fuel cell itself.

On the other hand, in a polymer electrolyte fuel cell,
Since the solid polymer membrane itself is acidic, the separator sandwiching the solid polymer membrane is required to have acid resistance, and in addition, hydrogen or oxygen as a fuel gas or water as a reaction product is used as a separator. It is required that the flow path for the fluid flow is made of a material having a high corrosion resistance that can prevent the formation of an oxide film and the like, because the flow path directly contacts the gas or the generated water.

[0006] As this type of separator for a polymer electrolyte fuel cell, the following (1) to (5) have been proposed. A sintered carbon separator obtained by subjecting a flat sintered carbon to cutting machining and forming a plurality of convex portions on the surface thereof. As shown in FIG. 9, a plurality of protrusions 31 are formed on the surface of the flat plate member 30 by molding a flat plate member obtained by impregnating or mixing the expanded graphite alone or a strength improving material such as a phenol resin or a pitch into the expanded graphite. And, if necessary, a metal plate 32 on the back side of the flat plate member 30.
And an expanded graphite separator formed by laminating an expanded graphite film 33. As shown in FIG. 10, a metal plate 34 is pressed so that a plurality of convex portions 35 are formed on the surface thereof, and a precious metal such as silver, zinc, or aluminum is formed on both front and back surfaces of the pressed metal plate 34. A metal separator formed by plating the film 36.

[0007]

However, among the above-mentioned conventional separators for polymer electrolyte fuel cells, the sintered carbon separator has a flat plate portion whose thickness is reduced to 1.0 mm or less by cutting machining. Not only is it difficult to perform the process, but even if the thickness of the flat plate portion can be reduced to about 1.0 mm, the mechanical strength of the thin flat plate portion is small. There is a problem that damages such as cracks are likely to occur during the cutting process.

[0008] In the expanded graphite separator, the expanded graphite is inherently poor in fluidity at the time of working and molding, so that not only the mechanical strength is small and the thickness cannot be reduced.
Abnormalities and defects such as cracks and swelling are likely to occur on the corner surface of the convex portion 31 forming the gas flow path, and it is not possible to mold the shape into a shape with high dimensional accuracy. Even when a strength improving material such as a phenolic resin is blended, although the mechanical strength is somewhat improved, the blending of the strength improving material which is originally inferior in electrical conductivity tends to deteriorate the electrical characteristics of the entire separator. Further, there is a problem that it is difficult to precisely mold the gas flow path because the mold is used to mold a thick plate member.

Further, in the case of the metal separator described above,
It is technically difficult to form the top end surface of the convex portion 35 into a precise flat shape, and it is impossible to avoid the occurrence of R at the corner portion of the convex portion 35. It is said that the contact area is reduced, and as a result, the electrical resistivity when a large number of separators are stacked during fuel cell assembly is increased, thereby hindering efficient electrical conductivity and deteriorating the electrical characteristics of the entire fuel cell. There's a problem. Incidentally, it is required that the electrical conductivity (electrical resistivity) of this type of separator be as small as possible.

[0010] The present invention has been made in view of the above-described circumstances. Even if the thickness of the fuel cell itself is reduced enough to satisfy the requirements for the reduction of the installation area and the weight reduction, excellent mechanical strength is obtained. It is an object of the present invention to provide a fuel cell separator capable of exhibiting excellent electrical characteristics while maintaining extremely high molding accuracy in the shape and dimensions of the gas flow path while maintaining the same, and a method for manufacturing the same.

[0011]

In order to achieve the above object, a fuel cell separator according to the first aspect of the present invention is a fuel cell separator mainly comprising a sheet-shaped member and a projection-forming member. The convex member is made of expanded graphite, and the sheet member is made of a material having a higher mechanical strength than the convex member made of expanded graphite. The expanded graphite convex part forming member is press-fitted into a plurality of holes of a predetermined shape formed by penetrating in the thickness direction thereof, and the two are integrated to form a plurality of parts on the surface of the sheet-like member. Are formed, and the protrusion forming member is made of expanded graphite.
Place the material in a direction perpendicular to the plane of the sheet
It is characterized by being formed by .

Further, the method for manufacturing a fuel cell separator according to the invention according to claim 7 is mainly based on only the flat plate portion.
A method for manufacturing a fuel cell separator comprising a sheet-shaped member and a convex-forming member, wherein the convex-forming member is made of expanded graphite and the sheet-like member is made of expanded graphite. A step of forming a plurality of predetermined-shaped holes by penetrating the sheet-shaped member having high mechanical strength in the thickness direction thereof, The expanded graphite material forming the expanded graphite convex portion forming member is flattened on a sheet-like member .
A plurality of projections are formed on the surface of the sheet-like member by disposing them in a direction perpendicular to the surface, press-fitting the sheet-like member from the back side to the front side, and integrating them together. And step are included.

According to the first and seventh aspects of the present invention, a sheet-like member consisting only of a flat plate portion and made of a material having high mechanical strength, and a conductive member dedicated to forming a convex portion are provided. Forming member made of expanded graphite, which is a material having excellent permeability and gas impermeability, is separately formed, and the forming member is press-fitted into a hole of a predetermined shape formed in the sheet-like member. By combining the two members as described above, it is possible to keep the mechanical strength required for the separator sufficiently while reducing the thickness of the flat plate portion and satisfying the requirements of reducing the installation area of the entire fuel cell and reducing the weight. At the same time, without forming abnormalities or defects such as cracks and swelling on the surface of the corners of the projections forming the gas flow path, the projections of a predetermined shape and dimensions are accurately molded to achieve excellent electrical characteristics. To have It is possible. In particular, since the top end surface of the separator convex portion that is in contact with the electrode is flat and made of expanded graphite, it has excellent compatibility with the electrode, and the electrical resistivity of the contact portion is reduced to improve the electrical characteristics. As a result, the performance of the fuel cell can be improved.

Here, it is desirable that the sheet-like member is made of at least one kind of flat plate material selected from the group consisting of metal, sintered carbon and resin. In addition, it is possible to reliably maintain a strength sufficient to withstand a tightening force or the like that acts upon assembling the fuel cell despite the thinning.

Further, the expanded graphite sheet material may be formed by swirling the expanded graphite sheet material.
In the case of using a material formed by winding in a wound shape or a material formed by laminating a plurality of expanded graphite sheet materials as described in claim 4, the volume of the protrusion forming member is The resistivity becomes very low, and the electrical characteristics of the entire separator can be further improved.

Further, as the sheet-like member, as described in claim 5, 6 or 8, a sheet-like material obtained by coating an expanded graphite film on the front surface, the back surface, or both the front and back surfaces of a metal or resin plate material is used. In addition to the acid resistance required for the separator sandwiching the acidic solid polymer membrane, the corrosion resistance prevents the formation of an oxide film even when it comes in contact with fuel gas such as hydrogen or oxygen or reaction product water. It is possible to have.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. First, the configuration and operation of a polymer electrolyte fuel cell as an embodiment of a fuel cell separator will be briefly described with reference to FIGS.
The polymer electrolyte fuel cell 20 is formed of, for example, a solid polymer membrane 1 which is an ion exchange membrane formed of a fluorine-based resin, and a carbon cloth, carbon paper or carbon felt woven with carbon fiber yarns. A plurality of sets of single cells 5 each comprising an anode 2 and a cathode 3 serving as a gas diffusion electrode forming a sandwich structure sandwiching the molecular film 1 from both sides and separators 4 and 4 further sandwiching the sandwich structure from both sides are laminated. It has a stack structure in which current collector plates (not shown) are arranged at both ends.

As shown in FIG. 2, the two separators 4 have fuel gas holes 6 and 7 containing hydrogen at their peripheral portions.
And oxidizing gas holes 8 and 9 containing oxygen and cooling water holes 10 are formed. When a plurality of sets of the single cells 5 are stacked,
Each hole 6, 7, 8, 9, 10 of each separator 4 penetrates through the inside of the fuel cell 20 in the longitudinal direction, and the fuel gas supply manifold, fuel gas discharge manifold, oxidizing gas supply manifold, oxidizing gas discharge manifold, cooling It is designed to form a channel.

Also, by forming a large number of projections on the surface of both separators 4, a groove 11 is formed between the projections.
The groove 1 is formed as shown in FIG.
A fuel gas flow path 12 is formed between the surface of the anode 1 and the anode 2, and an oxidizing gas flow path 13 is formed between the groove 11 and the surface of the cathode 3.

In the polymer electrolyte fuel cell 20 having the above-described structure, a fuel gas containing hydrogen supplied to the fuel cell 20 from a fuel gas supply device provided outside passes through the fuel gas supply manifold. The fuel gas is supplied to the fuel gas flow channel 12 of each unit cell 5 and undergoes an electrochemical reaction on the anode 2 side of each unit cell 5 on the anode 2 side as described in the above formula (1). The fuel gas is discharged from the fuel gas passage 12 of the cell 5 to the outside via the fuel gas discharge manifold. At the same time, an oxidizing gas (air) containing oxygen supplied to the fuel cell 20 from an oxidizing gas supply device provided outside is supplied to the oxidizing gas passage 13 of each unit cell 5 via the oxidizing gas supply manifold. Is supplied to the cathode 3 side of each unit cell 5 to cause an electrochemical reaction as shown in the above-mentioned equation (2), and the oxidized gas after the reaction flows from the oxidized gas flow path 13 of each unit cell 5 to the oxidized gas. The gas is discharged to the outside via the gas discharge manifold.

With the electrochemical reactions of the above formulas (1) and (2), the electrochemical reaction shown in the above formula (3) progresses as a whole in the fuel cell 20, and the chemical energy of the fuel is directly converted to the electric energy. By converting to energy, predetermined battery performance is exhibited. In addition, the fuel cell 20 generates heat because it is operated in a temperature range of about 80 to 100 ° C. due to the properties of the solid polymer membrane 1. Therefore, during operation of the fuel cell 20, the fuel cell 2 is supplied from a cooling water supply device provided outside.
By supplying cooling water to the cooling water channel 0 and circulating the cooling water in the cooling water channel, a rise in the temperature inside the fuel cell 20 is suppressed.

Next, the structure of the separator 4 in the polymer electrolyte fuel cell 20 having the above-described structure and operation and a method of manufacturing the same will be described. FIG. 4 is a partially cutaway perspective view showing a first embodiment of a fuel cell separator 4 according to the present invention. The fuel cell separator 4 includes a sheet-like member 14 and a protruding member 15 made of expanded graphite. Consists of As the sheet-like member 14, a metal such as SUS,
1 having a higher mechanical strength than the expanded graphite convex member 15 selected from the group consisting of sintered carbon and resin.
This sheet-like member 1 is made of a kind of flat plate material.
A plurality of holes 16 having a predetermined shape are formed in the hole 4 in the thickness direction by press working or the like.

The sheet-like member 1 having such a hole 16
5 is set on the upper surface of a lower mold 17 having a concave portion 17a at a position corresponding to the convex portion so that the back surface 14a faces upward, and the set sheet-like member 14 is set as shown in FIG. An upper die 18 having a movable press die 18a is disposed at a position corresponding to the above-mentioned protrusion forming portion, and an expanded graphite is formed on the back surface of the sheet-like member 14 below the movable press die 18a in the upper die 18. Convex part forming member 15
Place. In this state, after the upper die 18 and the lower die 17 are brought close to each other to clamp and fix the sheet-like member 14, the movable pressing die 18
a is pressed toward the lower mold 17 to thereby press-fit the convex portion forming member 15 made of expanded graphite into the hole 16 of the sheet-like member 14 to press-fit the two members 14, 15.
By forming a plurality of convex portions 19 on the surface of the sheet-like member 14, the groove portion 11 serving as the fuel gas flow channel 12 or the oxidizing gas flow channel 13 is formed between the adjacent convex portions 19, 19. Has formed.

FIG. 6 is a partially cutaway perspective view showing a second embodiment of a fuel cell separator 4 according to the present invention. In this fuel cell separator 4, a sheet member 14 is made of SUS.
And the like, and the front and back surfaces of a metal flat plate material 14a are coated with expanded graphite films 14b and 14c, respectively. Other configurations and manufacturing methods are the same as those described in the first embodiment. Description is omitted. In addition,
In the second embodiment, the expanded graphite films 14b and 14c on both the front and back surfaces of the metal flat plate material 14a have fine irregularities formed on the surface of the metal flat plate material 14a, or are coated with an adhesive such as a phenolic resin. Thereafter, the expanded graphite powder is sprayed, and then formed by pressure roller molding to form a coating by mechanically or chemically bonding.

FIG. 7 is a partially cutaway perspective view showing a third embodiment of a fuel cell separator 4 according to the present invention. The fuel cell separator 4 is composed of an expanded graphite convex part forming member 1.
5, for example, the sheet material 15a is spirally wound many times so that the long strip-shaped expanded graphite sheet material 15a can be arranged in a direction perpendicular to the plane of the sheet member 14, Since a structure formed by shaping into a convex shape is used, and the other configuration and manufacturing method are the same as those described in the first embodiment, detailed description will be omitted.

FIG. 8 is a partially cutaway perspective view showing a fourth embodiment of a fuel cell separator 4 according to the present invention. The fuel cell separator 4 is composed of an expanded graphite projection forming member 1.
As No. 5, a material formed by laminating a plurality of strip-shaped expanded graphite sheet materials 15b is used, and the other configuration and manufacturing method are the same as those described in the first embodiment. Detailed description is omitted.

The fuel cell separator 4 having the structure shown in each of the above embodiments has only a flat plate portion, and has a sheet-like member 14 having a large mechanical strength, and has excellent conductivity and gas impermeability only for forming the convex portion. The convex material forming member 15 made of expanded graphite, which is a material for
6 so that the protrusion forming member 15 is press-fitted to the both members 1.
By combining the elements 4 and 15, the thickness t of the flat plate portion is reduced to satisfy the requirements of reducing the installation area of the entire fuel cell 20 and reducing the weight thereof, while at the same time maintaining sufficient mechanical strength required for the separator 4. Without causing abnormalities or defects such as cracks and swelling on the corner surfaces of the convex portions 19,
The convex portion 19 and the groove portion 11 can be formed into a predetermined shape and a predetermined size with high precision, and can have excellent electrical characteristics. In particular, since the top end surface of the separator projection 19 in contact with the electrodes (anode 3 and cathode 4) sandwiching the solid polymer membrane 1 from both sides is flat and is made of expanded graphite,
It has excellent compatibility with the electrodes 3 and 4, and it is possible to improve the electric characteristics by reducing the electric resistivity of the contact portion, and to improve the fuel cell performance.

In particular, since the sheet-like member 14 is made of a flat material such as metal, resin or sintered carbon, the sheet-like member 14 has a sufficient tightening force acting upon assembling the fuel cell 20 despite the thinning. It is possible to reliably maintain the strength to withstand.

Further, as the convex portion forming member 15 made of expanded graphite, a member formed by winding an expanded graphite sheet material 15a as shown in the third embodiment, or as shown in the fourth embodiment, In the case of using a material formed by laminating a plurality of expanded graphite sheet materials 15b, the protrusion forming member 15 is used.
Has a very low volume resistivity, and the electrical characteristics of the entire separator 4 can be further improved.

Further, as shown in the second embodiment, the sheet-shaped member 14 is made of a metal or resin plate material 14.
By using a material in which the expanded graphite films 14b and 14c are coated on both the front and back surfaces of a, not only the acid resistance required for the separator 4 sandwiching the acidic solid polymer film 2 but also the acid resistance required
Corrosion resistance for preventing formation of an oxide film or the like even when contacting with hydrogen or oxygen serving as a fuel gas or water serving as a reaction product can be sufficiently provided.

[0031]

EXPERIMENTAL EXAMPLES Hereinafter, the present invention will be described in more detail with reference to experimental examples. Strength in the fuel cell separator of the present invention corresponding to Examples 1 to 3 and the conventional fuel cell separator corresponding to Comparative Examples 1 and 2, which were manufactured to have specifications as shown in Table 1. Each item of electrical contact resistance, molding accuracy, and corrosion resistance was measured and evaluated by the following test methods, and the results shown in Table 2 were obtained.

Strength: Measured according to the test method specified in JIS K7203. Electric contact resistance: Two separators were placed between copper plate electrodes and pressed, and then measured by measuring the current and voltage of the electrodes by a four-terminal method. Molding accuracy: R at the corner of the projection forming the gas flow path is 0.2
mm or less were rated as ○, and those exceeding 0.2 mm were rated as x. Corrosion resistance: Corrosion points were counted while observing the surface condition of the sample after the immersion treatment. Here, the corrosion area is 0.
When the number of minute corrosion portions of 01 mm ² or less is 0 to 2 / cm ² , when the number is 3 to 10 / cm ² △, 10 / c
If exceeding m ² was ×.

[0033]

[Table 1]

[0034]

[Table 2]

As is apparent from Table 1 above, the fuel cell separators of the present invention corresponding to Examples 1 to 3 all have the thickness t of the flat portion of the sheet member reduced to 1.0 mm or less. As is clear from Table 2, it is possible to maintain excellent mechanical strength and molding accuracy, and furthermore, the electrical contact resistance when the separator is stacked is small, and the corrosion resistance is improved. Is also excellent. On the other hand, the conventional fuel cell separator corresponding to Comparative Example 1 has a molding thickness and corrosion resistance that are comparable to those of the product of the present invention, but the flat plate has a wall thickness of 1.2 mm and is required as a separator. Not only does it not achieve the required thinness, but also the mechanical strength is insufficient. Also,
The conventional fuel cell separator corresponding to Comparative Example 2 has little problem with respect to thinness and mechanical strength, but is extremely inferior in terms of molding accuracy and adversely affects the efficient electromotive action of the fuel cell. I understood.

[0036]

As described above, according to the first and seventh aspects of the present invention, the thickness of the flat plate portion of the separator can be reduced to satisfy the demand for a reduction in the installation area and the weight of the entire fuel cell. In addition to maintaining sufficient mechanical strength required for the projections, the projections of the specified shape and dimensions can be very It can be molded with high precision to have excellent electrical characteristics. In particular, it is possible to improve the conformability with the electrode by flattening the top end surface of the separator convex portion in contact with the electrode, to reduce the electrical resistivity of the contact portion, to improve the electrical characteristics, and thereby to remarkably improve the fuel cell performance. It has the effect of being able to.

According to the third and fourth aspects of the present invention, in addition to the above effects, the volume resistivity of the projection-forming member can be made extremely low, and the electrical characteristics of the entire separator can be further improved. it can.

Further, according to the invention as set forth in claim 5, 6, or 8, in addition to the above-mentioned effects, not only the acid resistance required for the separator sandwiching the acidic solid polymer membrane, but also
Even if it comes into contact with hydrogen or oxygen as a fuel gas or water as a reaction product, the formation of an oxide film or corrosion damage can be prevented, and excellent corrosion resistance can be exhibited.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a configuration of a stack structure constituting a polymer electrolyte fuel cell provided with a separator of the present invention.

FIG. 2 is an external front view of a separator in the polymer electrolyte fuel cell.

FIG. 3 is an enlarged cross-sectional view of a main part showing a configuration of a single cell which is a structural unit of the polymer electrolyte fuel cell.

FIG. 4 is a partially cutaway perspective view showing a first embodiment of a fuel cell separator according to the present invention.

FIG. 5 is a cross-sectional view for explaining a method for manufacturing the fuel cell separator.

FIG. 6 is a partially cutaway perspective view showing a second embodiment of the fuel cell separator according to the present invention.

FIG. 7 is a partially cutaway perspective view showing a third embodiment of the fuel cell separator according to the present invention.

FIG. 8 is a partially cutaway perspective view showing a fourth embodiment of the fuel cell separator according to the present invention.

FIG. 9 is a partially cutaway perspective view showing an example of a conventional fuel cell separator.

FIG. 10 is a partially cutaway perspective view showing another example of a conventional fuel cell separator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 solid polymer membrane 4 fuel cell separator 14 sheet member 14 a flat plate material 14 b, 14 c expanded graphite film 15 expanded graphite convex portion forming member 15 a, 15 b expanded graphite sheet material 16 holes 19 convex portion 20 fuel cell

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shoji Kato 541-1, Shimouchi Shinto bat, Mita City, Hyogo Prefecture Inside the Mita Plant of Nippon Pillar Industry Co., Ltd. (72) Inventor Kiyoshi Shimoyama Shimouchi, Mita City, Hyogo Prefecture No. 541 of the priest's stadium The inside of the Mita factory of Nippon Pillar Industry Co., Ltd. (56) References JP-A-2000-1248 (JP, A) JP-A-5-74469 (JP, A) JP-A-62-272465 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01M 8/00-8/24

Claims (8)

(57) [Claims] 1. A fuel cell separator mainly comprising a sheet-shaped member and a projection-forming member, wherein the projection-forming member is made of expanded graphite, and the sheet-shaped member is made of expanded graphite. The expanded graphite convex portion is formed in a plurality of holes of a predetermined shape which are formed of a material having higher mechanical strength than the forming member and are formed by penetrating the sheet-like member having high mechanical strength in the thickness direction thereof. A plurality of protrusions are formed on the surface of the sheet-like member by press-fitting the member and integrating them.
The above-mentioned convex part forming member uses the expanded graphite material as a flat sheet-shaped member.
A separator for a fuel cell, wherein the separator is formed so as to be arranged in a direction perpendicular to a plane . 2. The fuel cell separator according to claim 1, wherein said sheet-like member is made of at least one kind of flat plate material selected from the group consisting of metal, sintered carbon, and resin. 3. The fuel cell separator according to claim 1, wherein the expanded graphite convex portion forming member is formed by spirally winding an expanded graphite sheet material. 4. The fuel cell separator according to claim 1, wherein the expanded graphite protrusion forming member is formed by laminating a plurality of expanded graphite sheet materials. 5. The fuel cell separator according to claim 1, wherein the sheet-like member is formed by coating a surface of a flat metal or resin material with an expanded graphite film. 6. The fuel cell separator according to claim 1, wherein the sheet-like member is formed by coating an expanded graphite film on a back surface of a metal or resin flat plate material. 7. A method for manufacturing a fuel cell separator comprising a sheet-shaped member mainly comprising only a flat portion and a projection-forming member, wherein said projection-forming member is made of expanded graphite and said sheet The sheet-shaped member is made of a material having a higher mechanical strength than the expanded graphite protrusion forming member, and a plurality of holes having a predetermined shape are formed by penetrating the sheet-shaped member having the higher mechanical strength in the thickness direction. form a step, the expanded graphite projection forming member into the hole of a predetermined shape
Make the expanded graphite material perpendicular to the plane of the sheet-like member
Disposed in a direction to and forming a plurality of convex portions on the surface of the sheet-shaped member by integrating both being pressure inserted and fitted toward the surface side from the back side of the sheet-like member, inclusion A method for producing a fuel cell separator. 8. The method for producing a fuel cell separator according to claim 7, further comprising a step of coating at least the surface of the front and back surfaces of the flat plate material constituting the sheet member with an expanded graphite film.