JPH11195422A - Manufacture of separator for fuel cell and the separator for the fuel sell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a separator having a sufficient conductivity and a gas impermeability according to an easy manufacturing method. SOLUTION: Material powder composed of carbon powder and binder is prepared, first of all, in order to manufacture a separator (step S100). A quantity of the binder used in this step is less than a theoretical quantity of the binder required theoretically to close a cavity formed inside of a carbon member obtained by press molding on the assumption that only the carbon powder is press molded in the conditions of heat press molding carried out later. A separator member is obtained by heat press molding the prepared material powder in a die. The separator member is impregnated with a prescribed impregnant (step S130), then the separator is finished by heat curing the impregnant after cleaning its surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a fuel cell separator and a fuel cell separator, and more particularly, to a fuel cell comprising a plurality of single cells stacked, provided between adjacent single cells. The present invention relates to a fuel cell separator that forms a fuel gas flow path and an oxidizing gas flow path between electrodes and separates a fuel gas and an oxidizing gas, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Heretofore, as a fuel cell separator of this type, there has been known a separator obtained by molding a material obtained by adding a predetermined binder to carbon powder as a raw material, followed by firing, carbonization and graphitization. (See, for example, JP-A-8-22
No. 2241). When carbonized and graphitized by firing the molded carbon material in this way, phenol resin and the like added as a binder to the carbon material generates water in the firing process, and the generated water enters the separator. Bubbles may be generated, and the gas impermeability of the fired separator may be impaired. Therefore, usually, in order to ensure gas impermeability of the separator, a process of impregnating the calcined separator with a thermosetting resin such as a phenol resin to block generated bubbles is performed.

Alternatively, as another method of manufacturing a separator, there has been proposed a method in which a mixture of a graphite material and a predetermined amount of a phenol resin as a binder is heated and press-molded at a temperature at which the resin does not become graphitic ( For example,
JP-A-60-246568 and the like). With such a configuration, the steps of carbonization and graphitization are not required, so that the manufacturing process can be simplified, and a separator that achieves sufficient conductivity and gas impermeability can be easily manufactured. it can.

[0004]

However, of the two methods described above, when a fuel cell separator is manufactured by firing formed carbon to carbonize and graphitize, the firing step involves the following steps. The entire carbon member shrinks. Therefore, usually, a material obtained by adding a binder to a raw material is formed into a block shape, fired, and cut out from the fired block-shaped carbon material to obtain a plate-like member. Processing was performed to obtain a desired separator shape. When the above-described operation of resin impregnation is performed on the member that has been machined into the desired shape, the separator is completed. As described above, when the manufacturing method including the firing step is used, there is an inconvenience that the entire manufacturing process is complicated, such as a need for a mechanical processing step, thereby increasing the manufacturing cost.

On the other hand, when a fuel cell separator is manufactured by adding a binder made of a thermosetting resin to a graphite material and performing hot press molding at a temperature at which the resin does not become graphitic, a hot press molding is required. Although a separator having a shape can be easily manufactured, since a binder is added to the graphite material, the conductivity of the separator may be impaired due to the effect of the binder, and the resistance may increase. That is, as the amount of the binder having no conductivity increases, the conductivity of the entire separator also decreases.
In addition, during hot press molding, a binder may be deposited on the surface of the separator, and when a fuel cell is assembled using such a separator, the contact resistance between the separator and the electrode increases. In order to prevent such inconveniences, a configuration may be considered in which the separator surface is removed after hot press molding to remove the binder deposited on the surface.However, with such a configuration, the surface is removed for each separator. Therefore, the manufacturing process is complicated, and the advantage of simple hot press molding is lost.

An object of the present invention is to solve such a problem and to produce a separator having sufficient conductivity and gas impermeability by a simple production method. The following configuration was adopted for the manufacturing method and the fuel cell separator.

[0007]

The method of manufacturing a fuel cell separator according to the present invention comprises the steps of: (a) pressing a raw material composed of a powder containing at least a conductive substance in a predetermined mold; Forming a separator member having a predetermined shape, and (b) impregnating the separator member formed in the step (a) with a predetermined impregnating agent;
Closing a gap formed between the powders constituting the raw material in the separator member with the impregnating agent, wherein a fuel cell separator is obtained from the separator member.

According to the method of manufacturing a fuel cell separator of the present invention having the above-described structure, a separator member is formed by pressure molding, and a separator is obtained from the separator member. The manufacturing process can be simplified as compared with a manufacturing method of cutting out a shape. Further, since the separator member is impregnated with the impregnating agent to close the gap formed in the separator member, a separator having sufficient gas impermeability can be manufactured.

Here, as the impregnating agent for impregnating the separator member, for example, a thermosetting resin having sufficient heat resistance at the operating temperature of the fuel cell can be used. When using a thermosetting resin, this is dispersed in a predetermined solvent, the separator member is immersed in the liquid, the impregnating agent is impregnated into the gap in the separator member, and the separator member is heated. What is necessary is just to heat-harden a resin. Also,
As long as the thermoplastic resin does not melt within the operating temperature range of the fuel cell, it can be used in place of the thermosetting resin.

In the method for producing a fuel cell separator according to the present invention, the conductive substance is carbon, and the powder to be subjected to the pressure molding is a powder made of carbon under the pressure at the time of the pressure molding. Assuming that the carbon member was obtained by pressure molding, a binder having a smaller amount than the theoretical amount required to close the gap formed between the carbon powders in the carbon member is further added to the carbon powder. The powder may be added.

With this configuration, the carbon separator can be manufactured by a simple method of pressure molding, and there is no need to perform complicated steps such as machining and firing. In addition, since the amount of the binder is smaller than the theoretical amount described above, the binder oozes out on the surface of the separator member formed by the pressure molding during the pressure molding as in the case of using the binder having the theoretical amount or more. There is no risk of forming a layer. When such a binder layer is formed on the surface of the separator member, the conductivity of the separator obtained from the separator member decreases, and when this separator is used in a fuel cell, the contact resistance in the fuel cell increases. . Further, if the binder oozes out during the pressure molding to form a layer, the releasability of the separator member after the pressure molding is deteriorated. Furthermore, the bleeding-out binder forms "burrs", and removing the burrs may complicate the manufacturing process.

[0012] Further, since the binder is used in an amount smaller than the theoretical amount, the carbon powder can be sufficiently adhered to each other in the separator member formed by pressure molding. Therefore, the binder layer is not formed between the carbon powders and the conductivity of the separator is not reduced. Further, when a thermosetting resin is used as the binder, the time required for curing the thermosetting resin is shorter due to the smaller amount of the binder, and the time required for manufacturing is shorter.

Here, the amount of the binder added to the carbon powder is not less than the minimum amount at which the member obtained by pressure molding has strength enough to withstand the impregnation step. The amount may be determined as appropriate so that the undesired amount of the binder does not ooze out on the surface. The theoretical value of such a binder amount is the amount obtained when assuming that a carbon member is obtained by pressing and molding only carbon powder, and in addition to the powder obtained by adding another substance to carbon powder. Alternatively, the amount may be obtained when it is assumed that the carbon member is formed. That is, if a powder obtained by further adding another substance such as a hydrophilic substance to carbon powder is used as the raw material,
When it is assumed that the carbon member is obtained by pressure-molding the powder to which the other substances are added, the amount of the binder actually used may be set as a smaller amount than the theoretically required amount of the binder. Of course, when another substance is further added to the carbon powder, if the amount of the other substance is small and has little influence, the theoretical amount obtained when only the carbon powder is used may be used.

In the method of manufacturing a fuel cell separator according to this embodiment, the powder containing at least the conductive substance may be a metal powder.

With such a structure, the metal separator can be manufactured by a simple method of pressure molding, and complicated steps such as machining are not required. Further, a lighter separator can be obtained as compared with a separator manufactured by cutting out a desired shape from a metal block. If the separator becomes lighter, the whole fuel cell using the same becomes lighter, which is particularly advantageous when this fuel cell is used as a power source for transportation.

Here, the raw material may be mixed with a powder of another substance in addition to the above-mentioned metal powder. For example, by further adding a hydrophilic substance,
The separator may be given predetermined hydrophilicity.

The method for manufacturing a fuel cell separator further comprises (c) sintering the separator member formed in the step (a), and the step (b) includes the step (c). It may be a step of impregnating the impregnating agent into the separator member sintered in the above.

By sintering the separator member in this manner, the conductivity and strength of the separator obtained from this separator member can be improved. Of course, if the separator member formed in the step (a) has sufficient conductivity and strength, the sintering step may not be performed.

In the method of manufacturing a fuel cell separator, the surface of the metal powder is formed of a substance which can maintain conductivity in an environment in which the manufactured separator is used when used in a fuel cell. Configurations that are coated powders are also suitable.

With this configuration, the separator does not deteriorate during use of the fuel cell, and the performance of the fuel cell does not deteriorate. The main cause of the deterioration of the metal separator during use of the fuel cell and the deterioration of the performance of the fuel cell is that the metal constituting the separator is oxidized and a layer made of an oxide metal having poor conductivity is used. Formed on the separator surface. Therefore, in order to maintain conductivity when the separator is used in a fuel cell, it is necessary to coat the metal powder with a metal which is hardly oxidized in a use environment of the fuel cell or which maintains conductivity even if oxidized. Is desirable. Of course, the metal powder may be coated with a substance other than a metal as long as it is stable and can maintain high conductivity in a use environment of the fuel cell.

Further, since each of the metal powders constituting the separator is coated with the above-mentioned substance, it is possible to obtain a separator which is much less likely to deteriorate as compared with a metal separator whose surface is coated only with the above-mentioned substance. Can be. In other words, even if the coating layer on the separator surface falls off due to deterioration over time or an external force applied during use of the fuel cell, since the individual metal powder constituting the separator is coated, the effect of the coating is lost. There is no end. On the other hand, when only the surface is coated with the above-mentioned substance, the effect of the coating is lost if a part of the coating layer falls off.

Here, the substance covering the metal powder is selected from titanium (Ti), nickel (Ni), titanium nitride (TiN), chromium nitride (CrN), gold (Au), and carbon (C). Metal. These metals have a low ionization tendency and are not easily oxidized, or have sufficient conductivity even if oxidized, and can achieve the above-described effects.

The method of manufacturing a fuel cell separator according to the present invention further comprises the steps of: (d) cleaning the separator member impregnated with the predetermined impregnating agent in the step (b), and then impregnating the separator member surface with the impregnation. A step of washing away the agent may be further provided.

According to such a method for manufacturing a fuel cell separator, the impregnating agent layer formed on the separator member surface in the step of impregnating the impregnating agent is removed by a simple method of washing, so that the conductivity deteriorates. The production process does not become complicated because the layer of the impregnating agent to be removed is removed. Here, the washing operation may be performed using water or warm water if the impregnating agent is water-soluble, and if a non-water-soluble impregnating agent is used, a solvent capable of dissolving the impregnating agent is appropriately selected. Cleaning may be performed.

In the method for producing a fuel cell separator, the impregnating agent may be a water-soluble thermosetting resin containing an acrylic resin as a main component and further copolymerizing an epoxy resin and an ester. Good. Since such a resin is water-soluble, the layer of the impregnating agent formed on the surface of the separator member by the operation of impregnating the separator member can be easily washed away by washing with warm water.

In the fuel cell separator of the present invention, the predetermined impregnating agent used in the step (a) is:
It may contain a hydrophilic substance.

By impregnating the impregnating agent containing a hydrophilic substance in this way, a predetermined hydrophilicity can be imparted to the separator. When the separator is imparted with hydrophilicity, the effect of improving drainage in the gas flow path formed by the concavo-convex structure provided on the separator surface inside the fuel cell using the separator is obtained. In other words, in a fuel cell, generated water is generated as the electrochemical reaction progresses, and this generated water stays in the gas flow path to block the flow path, which causes inconvenience. The drainage from the flow path is improved, and such inconvenience can be prevented. In addition,
The hydrophilicity of the impregnating agent is such that by impregnating the impregnating agent with the separator member, hydrophilicity can be imparted to the separator member such that the contact angle of the separator obtained from the separator member is 40 degrees or less. It is desirable that

The fuel cell separator of the present invention is a fuel cell separator comprising a metal member, wherein the metal member has minute voids scattered therein, and at least a part of the void is carbonized and graphitized. The gist is that a resin not filled is filled.

Since such a fuel cell separator is a metal member, it has sufficient conductivity as a fuel cell separator, and a resin that is not carbonized and graphitized fills minute spaces scattered inside the separator. As a result, sufficient gas impermeability as a fuel cell separator can be realized.

In the fuel cell separator of the present invention,
When the separator is used in a fuel cell, the metal member may be an aggregate of metal powders whose surfaces are coated with a metal capable of maintaining conductivity in an environment in which the separator is used.

In such a fuel cell separator, since the individual metal powders constituting the separator are coated with a metal that can maintain conductivity in a fuel cell operating environment, when the metal powder is used in a fuel cell, In addition, even when the surface layer is deteriorated, the conductivity is not impaired.

In the fuel cell separator of the present invention, the metal member may be a sintered metal member. By performing sintering, the conductivity and strength of the fuel cell separator formed of a metal member are further improved.

In such a fuel cell separator of the present invention, the metal coating the metal powder is titanium (T
i), a metal selected from nickel (Ni), titanium nitride (TiN), chromium nitride (CrN), gold (Au), and carbon (C). Since these metals have a low ionization tendency and are hardly oxidized, or have a property of maintaining sufficient conductivity even when oxidized, a separator, which is an aggregate of metal powder coated on the surface with these metals, is used as a fuel cell. By using this, the conductivity of the separator can be sufficiently ensured during use of the fuel cell.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the structure and operation of the present invention described above, embodiments of the present invention will be described below based on examples. First, for convenience of explanation,
The configuration and operation of a fuel cell including a separator manufactured according to the method for manufacturing a separator according to the first embodiment of the present invention will be described with reference to FIGS. 3 to 5, and subsequently, the first embodiment of the present invention will be described. Will be described.

A fuel cell provided with a separator manufactured according to the method of manufacturing a separator according to the first embodiment of the present invention has a stack structure in which a plurality of unit cells as constituent units are stacked. FIG. 3 is a schematic cross-sectional view illustrating the configuration of a single cell 28 which is a structural unit of a fuel cell, and FIG.
8 is an exploded perspective view showing the configuration of FIG. 8, and FIG. 5 is a perspective view showing the appearance of the stack structure 14 in which the single cells 28 are stacked.

The fuel cell of this embodiment is a polymer electrolyte fuel cell. The polymer electrolyte fuel cell includes a membrane made of a polymer having good conductivity in a wet state as an electrolyte layer. In such a fuel cell, a fuel gas containing hydrogen is supplied to the cathode side, and an oxidizing gas containing oxygen is supplied to the anode side, and the following electrochemical reaction proceeds.

H ₂ → 2H ⁺ + 2e ⁻ (1) (1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2) H ₂ + (1/2) O ₂ → H ₂ O (3) )

Equation (1) represents the reaction at the anode, and equation (2) represents the reaction at the cathode. In the entire fuel cell, the reaction shown in equation (3) proceeds. As described above, the fuel cell directly converts chemical energy of the fuel supplied to the fuel cell into electric energy, and is known as a device having extremely high energy efficiency. As shown in FIG. 3, a single cell 28, which is a structural unit of the fuel cell, includes an electrolyte membrane 21 and
Anode 22 and cathode 23, separator 30
a and 30b.

The anode 22 and the cathode 23 are gas diffusion electrodes having a sandwich structure with the electrolyte membrane 21 interposed therebetween. The separators 30a and 30b sandwich the anode 2 while sandwiching the sandwich structure from both sides.
A flow path for the fuel gas and the oxidizing gas is formed between the fuel cell 2 and the cathode 23. Anode 22 and separator 30a
Is formed between the cathode 23 and the separator 30b.
5P is formed. When actually assembling the fuel cell, a predetermined number of the single cells 28 are stacked to form the stack structure 14.

FIG. 3 shows that ribs forming a gas flow path are formed only on one side of each of the separators 30a and 30b. However, in an actual fuel cell, as shown in FIG. The ribs 54 and 55 are formed on both surfaces of the separators 30a and 30b, respectively. The ribs 54 formed on one surface of each of the separators 30a and 30b form a fuel gas flow path 24P with the adjacent anode 22, and the ribs 55 formed on the other surface of the separator 30 are provided in adjacent single cells. An oxidizing gas flow path 25 </ b> P is formed with the cathode 23. Therefore, the separators 30a and 30b form a gas flow path between the gas diffusion electrodes and separate the flow of the fuel gas and the oxidizing gas between the adjacent single cells. As described above, the separators 30a and 30b are not distinguished in terms of form or function in a fuel cell actually assembled, and are hereinafter generally referred to as separators 30.

The shape of the ribs 54 and 55 formed on the surface of each separator may be any shape as long as a gas flow path is formed and a fuel gas or an oxidizing gas can be supplied to the gas diffusion electrode. In this embodiment, the ribs 54 and 55 formed on the surface of each separator have a plurality of groove-like structures formed in parallel. In FIG. 3, the fuel gas flow path 24P and the oxidizing gas flow path 25P are shown in parallel to schematically represent the configuration of the single cell 28. However, in the separator 30 actually used when assembling the fuel cell, The ribs 54 and 55 are formed on both surfaces of the separator 30 so that the ribs 54 and the ribs 55 are in directions orthogonal to each other.

Here, the electrolyte membrane 21 is a proton-conductive ion exchange membrane formed of a solid polymer material, for example, a fluorine-based resin, and has good electric conductivity in a wet state. In this embodiment, a Nafion membrane (manufactured by DuPont) is used.
It was used. The surface of the electrolyte membrane 21 is coated with platinum as a catalyst or an alloy of platinum and another metal. As a method of applying the catalyst, a carbon powder supporting platinum or an alloy composed of platinum and another metal is prepared, and the carbon powder supporting the catalyst is dispersed in an appropriate organic solvent, and an electrolytic solution (eg, Aldrich Chemi) is used.
Cal Co., Nafion Solution) was added in an appropriate amount to form a paste, and screen printing was performed on the electrolyte membrane 21. Alternatively, a configuration in which a paste containing the carbon powder supporting the catalyst is formed into a film to form a sheet, and the sheet is pressed on the electrolyte membrane 21 is also suitable.

The anode 22 and the cathode 23 are both formed of carbon cloth woven with carbon fiber yarns. In the present embodiment, the anode 22 and the cathode 23 are formed of carbon cloth, but a configuration formed of carbon paper or carbon felt made of carbon fiber is also suitable.

The separator 30 is made of molded carbon obtained by compressing a carbon material. Around the separator 30, four hole structures are provided. The fuel gas holes 50 and 51 communicate with the ribs 54 forming the fuel gas flow path 34P, and the oxidizing gas holes 52 and 53 communicate with the ribs 55 forming the oxidizing gas flow path 35P. When the fuel cell is assembled, the fuel gas holes 50 and 51 provided in each separator 30 form a fuel gas supply manifold 56 and a fuel gas discharge manifold 57 that penetrate inside the fuel cell in the stacking direction. In addition, each separator 30
The oxidizing gas holes 52 and 53 provided in the oxidizing gas supply manifold 5 penetrate the fuel cell similarly in the stacking direction.
8 and the oxidizing gas discharge manifold 59 are formed.

When assembling the fuel cell including the above-described members, the separator 30, the anode 22, the electrolyte membrane 21, the cathode 23, and the separator 30 are sequentially stacked in this order. The plates 38 and 39 and the end plates 40 and 41 are arranged to complete the stack structure 14 shown in FIG. Current collector 3
The output terminals 36A and 37A are provided in the reference numerals 6 and 37, respectively, so that the electromotive force generated in the fuel cell can be output.

The order of lamination of the members when forming the stack structure 14 is as described above, but a predetermined sealing member is provided around the electrolyte membrane 21 in a region in contact with the separator 30. The sealing member serves to prevent the fuel gas and the oxidizing gas from leaking from the inside of each unit cell and to prevent the fuel gas and the oxidizing gas from being mixed in the stack structure 14.

The end plate 40 has two hole structures as shown in FIG. One is a fuel gas hole 42 and the other is an oxidizing gas hole 44. The insulating plate 38 and the current collecting plate 36 adjacent to the end plate 40 are similar to each other at positions corresponding to the two hole structures of the end plate 40.
Form a two-hole structure. The fuel gas hole 42 opens at the center of the fuel gas hole 50 provided in the separator 30. When the fuel cell is operated, the fuel gas hole 42 is connected to a fuel supply device (not shown), and a hydrogen-rich fuel gas is supplied into the fuel cell. Similarly, the oxidizing gas hole 44 is formed at a position corresponding to the center of the oxidizing gas hole 52 provided in the separator 30.
When operating the fuel cell, the oxidizing gas hole 44 is connected to an oxidizing gas supply device (not shown), and an oxidizing gas containing oxygen is supplied into the fuel cell. Here, the fuel gas supply device and the oxidizing gas supply device are devices that humidify and pressurize a predetermined amount of each gas and supply the gas to the fuel cell.

The end plate 41 has two hole structures at different positions from the end plate 40.
The insulating plate 39 and the current collecting plate 37 also have two hole structures at the same positions as the end plate 41. One of the hole gas structures 43 provided in the end plate 41
Is opened at a position corresponding to the center of the fuel gas hole 51 provided in the separator 30. The oxidizing gas hole 45 which is another hole structure is an oxidizing gas hole 53 provided in the separator 30.
Is opened at a position corresponding to the central part of. When operating the fuel cell, a fuel gas exhaust device (not shown) is connected to the fuel gas hole 43, and an oxidizing gas exhaust device (not shown) is connected to the oxidizing gas hole 45.

The stack structure 14 composed of the members described above is held in a state where a predetermined pressing force is applied in the stacking direction, and the fuel cell is completed. The configuration for pressing the stack structure 14 is not shown because it does not directly correspond to the main part of the present invention. In order to hold the stack structure 14 while pressing it, the stack structure 14 may be tightened using bolts and nuts, or a stack storage member having a predetermined shape may be prepared, and the stack storage member may be stacked inside the stack storage member. After the structure 14 is housed, both ends of the stack housing member may be bent to apply a pressing force to the stack structure 14.

Next, the flow of the fuel gas and the oxidizing gas in the fuel cell having the above configuration will be described. The fuel gas is introduced into the fuel cell from the above-described predetermined fuel gas supply device through a fuel gas hole 42 formed in the end plate 40. Inside the fuel cell, the fuel gas is supplied via a fuel gas supply manifold 56 to the fuel gas flow path 24P provided in each unit cell 28, and is subjected to an electrochemical reaction that proceeds on the cathode side of each unit cell 28. The fuel gas discharged from the fuel gas flow path 24P gathers in the fuel gas discharge manifold 57, reaches the fuel gas holes 43 of the end plate 41, is discharged from the fuel gas holes 43 to the outside of the fuel cell, and has a predetermined shape. It is led to a fuel gas discharge device.

Similarly, the oxidizing gas is introduced into the fuel cell from the above-mentioned predetermined oxidizing gas supply device through the oxidizing gas holes 44 formed in the end plate 40. In the fuel cell, the oxidizing gas is supplied to the oxidizing gas flow path 25P of each unit cell 28 via the oxidizing gas supply manifold 58, and is subjected to an electrochemical reaction that proceeds on the anode side of each unit cell 28. The oxidizing gas discharged from the oxidizing gas passage 25P gathers in the oxidizing gas discharge manifold 59 and reaches the oxidizing gas holes 45 of the end plate 41.
5 to the predetermined oxidizing gas discharging device.

Next, a method of manufacturing the separator 30 corresponding to the main part of the present invention will be described. FIG. 1 is an explanatory view showing a manufacturing process of the separator 30 of the present embodiment, and FIG.
FIG. 4 is an explanatory diagram showing a state of press forming in a process shown in FIG. The manufacturing process of the separator 30 shown in FIG. 1 is a process in which the raw material powder obtained by adding a binder to carbon powder is molded by a hot press. However, the amount of the binder to be added to the raw material powder is small, After the step, a step of impregnating the press-formed member with an impregnating agent is further provided.

First, prior to describing the method of manufacturing the separator 30, a necessary theoretical binder amount as a reference for the amount of binder added to the raw fuel powder will be described. FIG.
It is explanatory drawing showing the relationship between molding pressure and green compact bulk density. In FIG. 6, the horizontal axis represents the pressure applied to the raw material powder when pressing for molding. The vertical axis represents the bulk density of the green compact, which is obtained by press-molding only the carbon powder without adding a binder at the pressure shown on the horizontal axis, and calculating the theoretical density of the completed member by the density of the carbon crystal. It is a value relatively expressed as 100. Such a value of the theoretical density can be obtained by comparing the density obtained from the volume and the weight of the member obtained by press-molding only the powder with the density of the carbon crystal. The graph of FIG. 6 was created by measuring the bulk density of the green compact at five different points for the pressure during press molding.

When the carbon powder is press-molded as described above, the carbon particles in the carbon powder are pressed together. As a result, in the member obtained by the press molding, a gap having a size corresponding to the pressure at the time of pressing is formed. It is formed between each carbon particle. The size of this gap becomes smaller as the pressure during pressing increases. Therefore, as the pressure at the time of pressing increases, the density of the member obtained by press molding increases, and the airtightness (gas impermeability) of the member improves.

In FIG. 6, the theoretically required binder amounts are given in parentheses at the five points measured. The theoretical required binder amount is calculated from the theoretical density obtained as described above.
The amount of voids (the total amount of voids formed between the particles of carbon powder in the part obtained by pressure molding) in each member obtained by press-molding only the carbon powder is calculated, and a binder described later is used. The weight of the binder used to fill the voids is expressed as a percentage of the weight of the carbon powder. When a molded carbon member is manufactured by hot press molding by adding a binder to carbon powder, ideally, a molded carbon member having no voids can be manufactured by adding a binder corresponding to this theoretically required binder amount. Will be. Conventionally, when actually performing hot press forming, due to unevenness of pressure in the press surface due to the shape of the mold used for press forming, etc., it is possible to obtain molded carbon with sufficiently closed pores for,
Press molding was performed by adding a binder in an amount exceeding the theoretically necessary binder amount to the carbon powder.

Next, a method for manufacturing the separator 30 will be described with reference to FIG. To manufacture the separator 30,
First, a raw material powder is prepared (step S100).
This raw material powder was prepared by mixing flaky natural graphite powder as a carbon powder and methyl ethyl ketone (M
The mixture was uniformly mixed with a binder diluted with EK) to form a slurry, which was dried and then pulverized. Here, using a thermosetting resin and a curing accelerator as a binder,
The amount of the binder to be added was smaller than the theoretical amount of binder determined corresponding to the molding pressure based on FIG. 6 at the molding pressure selected in the heat press molding step described later.

The amount of the binder to be added to the carbon powder at the time of preparing the raw material powder in step S100 is smaller than the theoretical amount of binder as described above, and the thermosetting resin constituting the binder is once heated by press molding. At the time of softening, the amount is set such that the binder spreads sufficiently between the carbon powders and the strength of the member obtained by press molding is kept to a minimum. It is necessary that the strength of the member obtained by press molding be sufficiently resistant to the subsequent steps (treatment of impregnating with an impregnating agent).

Further, the amount of the binder added to the carbon powder also affects the time required for thermosetting the thermosetting resin during hot press molding. As the amount of the binder added to the carbon powder increases, the time required for thermosetting the thermosetting resin constituting the binder increases, so that the time required for hot press molding increases, thereby increasing the entire manufacturing process of the separator. The time required will be longer. Also, when the amount of the binder added to the carbon powder increases, the binder softened by heating exudes to the surface of the member formed by the press molding during the heat press molding, and partially adheres to the surface of the resulting separator. A binder layer is formed. Furthermore, if the amount of binder added to the carbon powder is large,
In the step of hot press molding, in a mold for press molding, a softened binder enters between members constituting the mold, and "burrs" are formed in the press-molded member. When such "burrs" occur, a step of removing the "burrs" is required after press molding. In addition, since the binder has a predetermined adhesiveness, the amount of the binder is large, and when the binder exudes to the surface of the member formed by press molding, when the member is removed from the press molding die. The releasability deteriorates.

In consideration of the above-mentioned inconvenience that may occur when the amount of binder is increased, the amount of binder to be added to the carbon powder is 50 to 8 times the theoretical amount of binder obtained from FIG.
It is preferably set to 0%. In this embodiment, the amount of the binder is 60 times the amount of the binder (10% of the carbon powder) required when the surface pressure during molding is 0.5 ton / cm ^2.
% (6% of carbon powder).

The thermosetting resin is a resin that causes a thermosetting reaction when heated to a predetermined temperature, and gives a predetermined hardness to the separator 30 mainly composed of carbon powder, Play a role in binding together. As a thermosetting resin that can be used as a binder, a thermosetting reaction occurs when heated,
It suffices if the operating temperature of the fuel cell and each component of the gas supplied to the fuel cell are stable. For example, phenol resins, epoxy resins, urea resins, melamine resins, unsaturated polyester resins, alkyd resins, and the like can be used. In order to realize sufficient binding properties and strength in the separator 30, a plurality of thermosetting resins may be selected and used in combination. In this example, as the thermosetting resin, an epoxy equivalent is a cresol novolac type epoxy resin having an equivalent of 214 grams,
A novolak type epoxy resin having an OH equivalent of 103 gram equivalent is used, and an imidazole compound is added to the epoxy resin as a curing accelerator for the epoxy resin.
It was added at a rate of 5%. The binder having such a configuration was diluted with an organic solvent (MEK) and added at the above ratio to the carbon powder.

In step S100, the slurry prepared by mixing the carbon powder and the binder was dried and pulverized to prepare the raw material powder. However, drying and granulation were simultaneously performed using a spray dryer or the like. You may do it. If the raw material powder can be uniformly mixed, dry kneading, in which the raw material powder is mixed without using a solvent, at a temperature at which the resin does not cure (from room temperature to about 100 ° C.), instead of the wet kneading described above, may be used. You may do it.

Here, at the time of adjusting the above-mentioned raw materials, powder materials were used. However, each of these materials was formed into a shape that can be mixed to an acceptable degree by wet kneading or dry kneading as described above. I just need. In order to mix the materials sufficiently, it is preferable that the raw material is composed of particles of about 1 to 300 μm.

The raw material powder thus prepared is put into a mold having a predetermined shape (step S110). A state in which the raw fuel powder is charged into the mold 60 is schematically shown in FIG. This mold 60 has an uneven surface on its inner surface by which the raw fuel powder is press-molded using the mold 60 so that the separator 30 having the shape shown in FIG. 4 can be formed. Here, the surface pressure is 0.5 ton / cm ² , 180
By pressing at 30 ° C., the separator 30 shown in FIG.
A separator member having the same shape as that described above is obtained (Step S120). The surface pressure at the time of pressing may be different as long as the separator 30 to be manufactured has sufficient strength, and the above-mentioned binder amount may be appropriately adjusted according to the selected surface pressure. As described above, the amount of the binder included in the separator member obtained in step S120 is smaller than the theoretically required amount of binder (6% of the carbon powder in the present embodiment). The density is about 92%, and the gas impermeability is insufficient.

At the time of press forming in step S120,
By heating the mold at 180 ° C., the thermosetting resin constituting the binder dissolves and a thermosetting reaction occurs, and a predetermined strength can be given to the separator member simultaneously with press molding. Here, the heating temperature at the time of press molding may be a condition under which the above-described resin dissolution and thermosetting reaction occurs, and is appropriately determined, for example, within a temperature range of 140 to 220 ° C. for 1 to 30 minutes. be able to. Alternatively, after press-molding in a temperature range (80 to 100 ° C.) in which the thermosetting resin dissolves but does not cause a thermosetting reaction, the formed separator member is placed in a predetermined heating furnace at 140 to 220 ° C. for 30 minutes. The thermosetting resin may be thermoset by heating for up to 600 minutes. In this case, by dissolving the thermosetting resin at the time of press molding, the thermosetting resin can be spread between the carbon powders and sufficient binding properties can be obtained. In addition, since it is not necessary to complete the thermosetting reaction at the time of pressing, the time of the pressing step can be reduced, and the thermosetting reaction can be performed collectively later, which is advantageous when a large number of separators are manufactured. Becomes The heating performed for the thermosetting reaction may be performed within a temperature range and a heating time in which the selected thermosetting resin can be thermoset and the constituent materials such as the thermosetting resin do not deteriorate.

When the above-described press molding is performed, if the air in the mold is taken into the raw material powder and the press is performed, air remains in the molded separator member and bubbles are generated in the separator member. May be formed.
The separator member is provided with sufficient gas impermeability by a step of impregnation with an impregnating agent described later, but in order to prevent undesired bubbles from being formed locally, the inside of the mold is pressed during press molding. Exhaust to 10 torr or less,
It is good also as composition which prevents that air remains in a separator member.

Since the separator member obtained in the step of hot press molding in step S130 has insufficient gas impermeability as described above, the separator member is then impregnated with an impregnating agent, Are filled with the impregnating agent to impart sufficient gas impermeability to the separator member (step S130). In this step S130, as the impregnating agent, it can be easily washed off from the surface of the separator member in a washing step described later, and can be thermally cured in a drying step described later to impart a predetermined hydrophilicity to the separator. (The separator impregnated with the impregnating agent has a contact angle of 40
Thermosetting resin). For example, an organic resin obtained by copolymerizing an epoxy resin and an ester resin with an acrylic resin as a main component, a silicate composite inorganic polymer (silicon resin), or the like can be used. The separator member is placed under vacuum (20 torr) in an impregnation tank filled with these impregnating agents.
Immersion under the following reduced pressure), followed by pressure impregnation (pressure 5a).
tm or more).

Next, the separator member impregnated with the impregnating agent is washed with warm water to wash away the impregnating agent adhering to the surface of the separator member (step S140). Further, the separator member whose surface has been cleaned is
It is dried at 50 ° C., and the thermosetting resin as the impregnating agent is thermoset (step S150) to complete the separator 30 having sufficient gas impermeability.

The separator 3 manufactured as described above
FIG. 7 shows a result of assembling a fuel cell using the sample No. 0 and examining the current-voltage characteristics. FIG. 7 also shows, as a comparative example, current-voltage characteristics in a fuel cell using a graphitized carbon produced according to a conventionally known technique and a separator made of molded carbon produced according to a conventionally known technique. Here, a separator made of graphitized carbon manufactured according to a conventionally known technique is obtained by kneading a carbon powder and a phenol resin, molding the mixture, firing and graphitizing the resultant, and then performing machining to form a predetermined shape. In addition, gas impermeability is ensured by impregnation with a resin. The separator made of molded carbon manufactured according to a conventionally known technique is manufactured by adding a sufficient amount of a binder made of a thermosetting resin to carbon powder, kneading the mixture, and then performing hot press molding. That is, when hot press molding is performed under the same conditions as in the above embodiment, the amount (specifically, the amount of carbon powder) exceeds the theoretical binder amount (10% of the amount of carbon powder) necessary to fill the voids in the molded carbon. 14%) of the separator.

As shown in FIG. 7, the fuel cell assembled using the separator 30 of the present embodiment has almost the same current-voltage characteristics as the fuel cell assembled using the conventionally known separator made of graphitized carbon. And excellent cell characteristics compared to a fuel cell assembled using a conventionally known separator made of molded carbon. That is, a sufficiently high output voltage could be maintained even when the output current value became large. Here, the inferior cell characteristics of a fuel cell assembled using a conventionally known separator made of molded carbon is that the binder dissolved by heating on the surface of the molded separator stains when molded by a hot press. And a binder layer is formed on the separator surface. Since the binder made of thermosetting resin does not have conductivity, when a fuel cell is assembled using such a separator, the internal resistance of the fuel cell increases and the output voltage when the output current value is large is sufficiently secured. It will be difficult to do.

According to the separator manufacturing method of the present embodiment described above, since the separator member is manufactured by hot press molding without performing the firing step, a machine for cutting out a predetermined shape from the fired body. Since a processing step is not required, the manufacturing process can be simplified and the manufacturing cost can be reduced. In addition, since the separator member is impregnated with the impregnating agent after the heat press molding step, a separator having sufficient gas impermeability and sufficient strength can be manufactured.

Further, in the separator manufacturing method of the present embodiment, the amount of the binder added to the raw material to be subjected to the hot press molding is theoretically necessary to completely close the voids formed between the carbon particles by the press molding. Since the binder amount is smaller than the required binder amount, the following effects can be obtained. First
In addition, the time required for thermosetting the thermosetting resin constituting the binder is shorter, and the time for performing the hot press molding can be shortened. Secondly, since no excessive binder is interposed between the carbon powders constituting the separator, the conductivity of the separator can be sufficiently ensured. When the hot press molding is performed by adding an amount of the binder exceeding the theoretical binder amount described above to the carbon powder, an excessive amount of the binder forms a binder layer between the carbon powders, and the carbon powder does not contact with each other, so that the carbon powder does not contact. May be impaired. When the amount of the binder is small as described above, since the carbon powder is press-formed in a state where the carbon powders are sufficiently in contact with each other, good conductivity can be secured.

Third, since excessive binder does not exude on the surface of the separator member during hot press molding, when a fuel cell is assembled using such a separator, the internal resistance of the fuel cell is reduced. Fuel cell showing sufficient current-voltage characteristics without increasing the fuel cell voltage. As in the past, when carbon powder mixed with an amount of binder exceeding the theoretical binder amount is hot-press-molded, a binder layer may be formed on the separator surface, and a fuel cell incorporating such a separator may be used. In such a case, the internal resistance of the fuel cell increases and the cell performance decreases. In order to avoid such a situation, it was necessary to further add a step of shaving off the binder layer that had exuded onto the surface of the separator in the manufacturing process of the separator.

Further, in the separator manufacturing method of the present embodiment, since the resin which can be easily washed away by hot water washing is used as the impregnating agent for impregnating the separator member manufactured by the hot press molding, it is easy to carry out hot water washing. By such an operation, it is possible to easily suppress an increase in contact resistance generated when the separators are stacked. Since the layer of the impregnating agent formed on the surface of the separator can be easily washed away by hot water washing, it is not necessary to perform a complicated mechanical treatment such as scraping off the surface of the separator.

In the method of manufacturing a separator according to this embodiment, a hydrophilic resin is used as an impregnating agent for impregnating the separator member manufactured by hot press molding.
Predetermined hydrophilicity can be imparted to the manufactured separator. By assembling a fuel cell using such a separator, it is possible to improve drainage in a gas flow path in the fuel cell, and the gas flow path in the fuel cell is blocked by water generated by a cell reaction or the like. It is possible to prevent the inconvenience of being caused. In the fuel cell, the electrochemical reaction shown in the above-described equations (1) to (3) proceeds, but at this time, as shown in the equation (2), generated water is generated on the anode side. In the case where the separator that forms the unevenness forming the gas flow path on the surface has hydrophilicity, the generated water is guided to the gas flow path wall surface having the hydrophilic property and is discharged. As a result, it is possible to prevent the gas flow path from remaining in the gas flow path and blocking the gas flow path.

In the first embodiment, the separator 3
Although the flaky natural graphite powder was used as the carbon powder used as the raw material of No. 0, other types of carbon powders may be used. In addition to the flaky natural graphite powder, for example, carbon black, thermally expanded graphite, or the like can be used, and may be appropriately selected in consideration of conditions such as cost.

In the first embodiment, carbon powder was used as a raw material of the separator, and a binder was added to the carbon powder, and the separator member obtained by hot press molding was used.
Although the separator was manufactured by impregnation with an impregnating agent, the same manufacturing method can be applied to a case where a metal material is used as a raw material of the separator. Normally, when a separator is manufactured from a metal material, a method of cutting out a member having a predetermined shape from a metal block is used, but the metal powder is used as a raw material, and the metal powder is press-molded to obtain the first embodiment. Similarly, a separator member can be manufactured, and the separator member can be further impregnated with an impregnating agent to manufacture a separator. Such a method will be described below as a second embodiment.

FIG. 8 is an explanatory view showing a manufacturing process of the separator 130 of the second embodiment. The separator 130 is
It has the same shape as the separator 30 of the first embodiment, and is used by being incorporated in the fuel cell described above, but is characterized by using metal powder as a raw material. Separator 130
First, raw material powder is prepared (step S200). In the second embodiment, as the raw material powder,
A metal powder obtained by tin plating each titanium particle of the titanium powder was prepared. In the metal powder used as the raw material powder, the powder base material may be any metal that is stable under the operating conditions (supplied gas and temperature) of the fuel cell, for example, titanium, nickel, chromium, stainless steel, etc. You can choose. When the separator is made of metal instead of carbon, the surface of the metal is generally further coated with a particularly stable metal for the purpose of imparting sufficient corrosion resistance to the separator. In this embodiment,
Each particle of the metal powder used as the raw material powder was plated. Examples of metals used for plating include titanium, nickel, titanium nitride, chromium nitride, gold, carbon,
Tin or the like can be used, and may be appropriately selected in consideration of durability, cost, and the like required for the fuel cell. In addition,
The particle size of the metal powder prepared in step S200 was several tens of μm.

The raw material powder thus prepared is put into a mold having a predetermined shape (step S210). The step of introducing the raw material powder into the mold is the same as the step S210 shown in FIG. 1 in the first embodiment, and the used mold is the same as the mold 60 shown in FIG. Mold. After putting the raw fuel powder into the mold of the predetermined shape,
When pressing is performed at a predetermined surface pressure, a metal separator member having the same shape as the separator 30 shown in FIG. 4 is obtained (Step S220). The surface pressure at the time of pressing is set as a pressure at which the separator 130 finally manufactured from the separator member obtained by press molding has sufficient strength. The temperature at the time of press molding may be room temperature, but it may be heated to about 100 ° C. to increase the fluidity of the raw material powder. In the present embodiment, press molding was performed under the conditions of 0.5 ton / cm ² and 80 ° C.

Next, the separator member obtained by the press forming in step S220 is sintered (step S225). By performing this sintering process, the conductivity and strength of the separator member are improved. Note that if the conductivity and strength of the separator member that is not subjected to the sintering process is sufficient for a separator to be incorporated in a fuel cell, the step S225 may not be performed. The separator member sintered in step S225 has a porosity (a ratio of the total amount of voids formed therein to the volume of the separator member) of about 20%, and the gas impermeability of the separator is insufficient. It is in a state.

As described above, the separator member obtained in the press molding step of step S225 has insufficient gas impermeability. Therefore, as in the first embodiment, the separator member is impregnated with an impregnating agent. To impregnate the gaps between the carbon powders constituting the separator member with the impregnating agent, thereby imparting sufficient gas impermeability to the separator member. Impregnating the separator member with an impregnating agent, cleaning the separator surface,
Steps S230 to S250 for drying and curing the impregnating agent are the same as steps S130 to S150 described in the first embodiment based on FIG. 1, and therefore detailed description is omitted. . By performing the same processes as in steps S130 to S150, the gaps in the separator member are closed with the impregnating agent to complete the separator 130 having sufficient gas impermeability.

A result of assembling a fuel cell using the separator 130 of the second embodiment manufactured as described above and examining the current-voltage characteristics thereof is shown in FIG. 7 together with the result of the first embodiment. As shown in FIG. 7, the fuel cell assembled using the separator 130 of the second embodiment exhibited sufficient cell characteristics superior to the fuel cell assembled using the conventionally known separator made of molded carbon. . That is, a sufficiently high output voltage could be maintained even when the output current value became large.

According to the method of manufacturing the separator of the second embodiment described above, the following effects can be obtained as in the method of manufacturing the separator of the first embodiment. That is, since the separator member is manufactured by press molding, a machining process for cutting out a predetermined shape is not required, so that the manufacturing process can be simplified and the manufacturing cost can be reduced. In addition, since the separator member is impregnated with the impregnating agent after the press molding step, a separator having sufficient gas impermeability can be manufactured. Furthermore, since a resin that can be easily washed away by hot water washing is used as an impregnating agent to be impregnated into the separator member, the simple operation of hot water washing increases contact resistance generated when the separators are stacked. Can be easily suppressed.
Since the layer of the impregnating agent formed on the surface of the separator can be easily washed away by hot water washing, it is not necessary to perform a complicated mechanical treatment such as scraping off the surface of the separator. Further, since the impregnating agent to be impregnated into the separator member is a resin having hydrophilicity, predetermined hydrophilicity can be imparted to the manufactured separator. Therefore,
By assembling a fuel cell using such a separator, it is possible to improve drainage in a gas flow path in the fuel cell, and the gas flow path in the fuel cell is blocked by water generated by a cell reaction or the like. It is possible to prevent the inconvenience of being caused.

Further, according to the method of manufacturing the separator of the second embodiment, since the raw material made of metal powder is pressed and formed, the metal material is cut into a predetermined shape from the metal block as compared with the case where the member is cut out from the metal block. There is an advantage that the degree of freedom of the shape at the time of manufacturing the separator made is increased. Therefore, as compared with the case of cutting out by machining, the manufacturing process can be simplified, and the irregularities and the like provided on the separator surface to form the gas flow path in the fuel cell can be designed to be more free. Becomes possible. In addition, by pressing the metal powder, in the separator, since voids are generated between the metal powder,
The weight of the separator is reduced as compared with a metal separator manufactured by cutting a predetermined shape from a metal block. Therefore, the weight of the entire fuel cell assembled using the separator can be reduced, which is particularly advantageous when manufacturing a fuel cell used as a power supply for transportation.

Further, since the raw material of the separator 130 is plated with individual metal powder, there is an effect that the corrosion resistance of the entire separator can be improved. That is, even if a part of the surface layer of the separator is damaged due to deterioration over time or external force applied to the separator during operation of the fuel cell, individual particles in the metal powder constituting the separator are plated. Therefore, the corrosion resistance does not decrease. On the other hand, a separator manufactured by cutting a member of a predetermined shape from a metal block is usually plated on the surface to improve corrosion resistance, but in such a case, plating is performed only on the surface of the separator. Since the layer is formed, it is difficult to realize sufficient corrosion resistance. That is, if a part of the surface plating layer is damaged by the above-mentioned deterioration or external force, the effect of protecting the inside of the separator is lost, and the corrosion resistance of the separator is reduced.

In the embodiment described above, the separator 3
Although the fuel cell including the fuel cell and the separator 130 is a polymer electrolyte fuel cell, the separator according to the present invention can be applied to other types of fuel cells if the manufactured separator can withstand the usage environment of the fuel cell. I do not care.

The embodiments of the present invention have been described above.
The present invention is not limited to such embodiments at all, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a manufacturing process of a separator 30 according to a first embodiment.

FIG. 2 is an explanatory diagram illustrating a state in which a separator 30 is manufactured by pressure molding.

FIG. 3 is a schematic cross-sectional view illustrating a configuration of a single cell 28.

FIG. 4 is an exploded perspective view illustrating a configuration of a fuel cell.

FIG. 5 is a perspective view illustrating an appearance of a stack structure 14 in which unit cells 28 are stacked.

FIG. 6 is an explanatory diagram illustrating a relationship between a molding pressure and a bulk density of a green compact.

FIG. 7 is an explanatory diagram showing current-voltage characteristics of a fuel cell assembled using the separator 30.

FIG. 8 is an explanatory diagram illustrating a manufacturing process of the separator 130 according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 14 ... Stack structure 21 ... Electrolyte membrane 22 ... Anode 23 ... Cathode 30a, 30b ... Separator 24P ... Fuel gas flow path 25P ... Oxidation gas flow path 28 ... Single cell 30 ... Separator 34P ... Fuel gas flow path 35P ... Oxidation gas flow path 36, 37 ... current collecting plate 36A, 37A ... output terminal 38, 39 ... insulating plate 40, 41 ... end plate 42 ... fuel gas hole 43 ... fuel gas hole 44 ... oxidizing gas hole 45 ... oxidizing gas hole 50, 51 ... fuel Gas holes 52, 53 ... Oxidizing gas holes 54, 55 ... Ribs 56 ... Fuel gas supply manifold 57 ... Fuel gas discharge manifold 58 ... Oxidizing gas supply manifold 59 ... Oxidizing gas discharge manifold 60 ... Mold 130 ... Separator

Claims (13)

[Claims] 1. A method of manufacturing a fuel cell separator, comprising: (a) press-forming a raw material comprising a powder containing at least a conductive substance in a predetermined mold to form a separator member having a predetermined shape. (B) impregnating the separator member formed in the step (a) with a predetermined impregnating agent to form a gap formed between the powders constituting the raw material in the separator member, A method of obtaining a fuel cell separator from the separator member. 2. The method for manufacturing a fuel cell separator according to claim 1, wherein the conductive substance is carbon, and the powder to be subjected to the pressure molding is formed under a pressure at the time of the pressure molding. Assuming that a carbon member was obtained by press-molding a powder made of carbon in the above, a binder having an amount smaller than the theoretical amount required to close the voids formed between the carbon powders in the carbon member. A method for producing a fuel cell separator, which is a powder further added to the carbon powder. 3. The method according to claim 1, wherein the powder containing at least the conductive substance is a metal powder. 4. The method for manufacturing a fuel cell separator according to claim 3, further comprising: (c) sintering the separator member formed in the step (a), wherein the step (b) is performed. And (c) impregnating the separator member sintered in the step (c) with the impregnating agent. 5. The metal powder whose surface is coated with a substance capable of maintaining conductivity in a use environment when the manufactured separator is used for a fuel cell. Of producing a fuel cell separator. 6. The material for coating the metal powder is titanium (Ti), nickel (Ni), titanium nitride (Ti).
N), chromium nitride (CrN), gold (Au), carbon (C)
The method for producing a fuel cell separator according to claim 5, wherein the metal is a metal selected from the group consisting of: 7. The method for producing a fuel cell separator according to claim 1, wherein (d) washing the separator member impregnated with a predetermined impregnating agent in the step (b), A method for manufacturing a fuel cell separator, further comprising a step of washing out the impregnating agent attached to the surface of the separator member. 8. The method for producing a fuel cell separator according to claim 7, wherein the impregnating agent is a water-soluble thermosetting resin containing an acrylic resin as a main component and further copolymerizing an epoxy resin and an ester. 9. The method for producing a fuel cell separator according to claim 1, wherein the predetermined impregnating agent used in the step (a) contains a hydrophilic substance. Method. 10. A fuel cell separator comprising a metal member, wherein the metal member has minute voids scattered therein, and at least a part of the void is filled with a resin that has not been carbonized and graphitized. Fuel cell separator. 11. The fuel according to claim 10, wherein the metal member is an aggregate of metal powders whose surfaces are coated with a metal capable of maintaining conductivity in an environment where the separator is used in a fuel cell. Battery separator. 12. The fuel cell separator according to claim 10, wherein the metal member is a sintered metal member. 13. The metal coating the metal powder is titanium (Ti), nickel (Ni), titanium nitride (Ti).
N), chromium nitride (CrN), gold (Au), carbon (C)
13. The fuel cell separator according to claim 11, which is a metal selected from the group consisting of: