JP2021170524A - Separator for fuel cell and method for manufacturing separator for fuel cell - Google Patents

Abstract

To provide a separator for a fuel cell that can suppress increase of a contact resistance, and a method for manufacturing the separator for a fuel cell.SOLUTION: A separator 20 has a base material 21. The base material 21 includes: a first conductive layer 50 containing a first conductive carbon material 51, the first conductive layer being formed in a resin material 52; and a second conductive material 60 containing a second conductive carbon material 61, the second conductive material being next to the first conductive layer 50 on at least one side of the first conductive layer 50 in a thickness direction and also being joined to the first conductive layer by the resin material 52.SELECTED DRAWING: Figure 2

Description

The present invention relates to a fuel cell separator and a method for manufacturing a fuel cell separator.

Patent Document 1 discloses a fuel cell separator in which a carbon material is dispersed in a resin. The separator is produced by heating and pressurizing a mixture of expanded graphite powder and a thermosetting resin or a thermoplastic resin using a mold.

Japanese Unexamined Patent Publication No. 11-354138

By the way, in the separator described in Patent Document 1, by pressurizing the mixture during production, the resin existing between the carbon materials exudes on both sides in the thickness direction of the separator, and the carbon material exudes the thickness of the separator. It may be unevenly distributed in the central part in the vertical direction. In this case, a region having a resin ratio higher than that of the other portions is formed in the vicinity of the surface of the separator. As a result, the contact resistance of the separator may increase.

An object of the present invention is to provide a fuel cell separator and a method for manufacturing a fuel cell separator capable of suppressing an increase in contact resistance.

The fuel cell separator for achieving the above object includes a base material, and the base material contains a conductive first carbon material, and has a first conductive layer formed in the resin material. It contains a conductive second carbon material, is formed adjacent to the first conductive layer on at least one side in the thickness direction of the first conductive layer, and is bonded to the first conductive layer via the resin material. A second conductive layer is provided.

According to the same configuration, the first conductive layer and the second conductive layer constituting the separator come into contact with each other in the thickness direction. As a result, a conductive path is formed inside the separator via the first conductive layer and the second conductive layer. Further, on the surface of the separator on which the second conductive layer is formed, it is suppressed that the ratio of the resin material is higher than that of the other portions. Therefore, an increase in the contact resistance of the separator can be suppressed.

In the fuel cell separator, the second conductive layer is preferably formed on both sides of the first conductive layer in the thickness direction.
According to the same configuration, the conductive paths are formed on both sides of the first conductive layer in the thickness direction. In addition, it is suppressed that the ratio of the resin material on both sides of the separator is higher than that of the other parts. Therefore, an increase in the contact resistance of the separator can be further suppressed.

In the fuel cell separator, the second carbon material constituting the second conductive layer bonded to the one side of the first conductive layer has first carbon particles and an average particle diameter of the first carbon particles. It is preferable that the surface of the second conductive layer is composed of only the second carbon material, including the second carbon particles having an average particle diameter smaller than that of the second carbon particles.

In the power generation section of a fuel cell, water is generated by an electrochemical reaction of the reaction gas supplied to the fuel cell. The water thus generated (hereinafter referred to as generated water) is discharged to the outside of the power generation unit by the pressure of the reaction gas. However, when the amount of produced water is large, the pressure loss of the reaction gas may increase excessively. Therefore, it is preferable that the generated water is discharged to the outside of the power generation unit at an early stage.

According to the above configuration, a large number of fine irregularities are formed on the surface of the second conductive layer formed on one side of the first conductive layer by the second carbon material containing the first carbon particles and the second carbon particles. Will be done. As a result, the surface of the separator on which the second conductive layer is formed is brought into contact with the power generation section, so that the generated water generated in the power generation section is discharged from the surface of the second conductive layer through a large number of fine irregularities. It becomes easy to be done. Therefore, the dischargeability of the produced water can be improved.

Further, according to the above configuration, the surface of the second conductive layer is composed of only the second carbon material. That is, the resin material of the first conductive layer is not exposed on the surface on one side of the separator. Therefore, an increase in the contact resistance of the separator can be suppressed.

Further, a method for manufacturing a separator for a fuel cell for achieving the above object is a plate material forming step of forming a plate material from a mixture in which a conductive first carbon material is dispersed in a resin material, and a plate material forming step in the thickness direction of the plate material. The thickness of the plate material is obtained by heating and pressurizing the plate material on which the conductive second carbon material is arranged and the plate material on which the second carbon material is arranged. A first conductive layer containing the first carbon material is formed in the central portion in the longitudinal direction, and a second conductive layer containing the second carbon material is adjacent to the first conductive layer on one side of the plate material. A step of forming a conductive layer to be formed is provided.

According to this method, in the conductive layer forming step, the plate material on which the second carbon material is arranged is heated and pressurized, so that the first carbon material dispersed in the resin material is unevenly distributed in the central portion in the thickness direction. Will come to do. On the other hand, a second conductive layer is formed adjacent to the first conductive layer via a resin material in the vicinity of at least one surface in the thickness direction of the plate material. Therefore, on the surface of the separator on which the second conductive layer is formed, it is suppressed that the ratio of the resin material is higher than that of the other portions. According to the separator manufactured in this way, it is possible to exert an action effect similar to the action effect of the above-mentioned fuel cell separator.

In the method for manufacturing a fuel cell separator, in the second carbon material arranging step, the second carbon material is arranged on both side surfaces in the thickness direction of the plate material, and in the conductive layer forming step, the plate material is said to be said. It is preferable to form the second conductive layer on both sides.

According to this method, it is possible to obtain an action and effect similar to the action and effect of the fuel cell separator.
In the method for producing a separator for a fuel cell, in the second carbon material arranging step, the second carbon material is arranged on the entire surface of the plate material on one side, and the first carbon particles are used as the second carbon material. It is preferable to use one containing the second carbon particles having an average particle size smaller than the average particle size of the first carbon particles.

According to this method, in the process of arranging the second carbon material, the entire surface on one side of the plate material is covered with the second carbon material containing the first carbon particles and the second carbon particles. As a result, the surface of the second conductive layer formed on one side of the plate material in the conductive layer forming step is likely to be composed of only the second carbon material. That is, the resin material is less likely to be exposed from the surface on one side of the separator. According to the separator manufactured in this way, since the action effect is similar to the action effect of the fuel cell separator, the discharge property of the produced water can be enhanced. In addition, an increase in the contact resistance of the separator can be suppressed.

According to the present invention, an increase in contact resistance of a fuel cell separator can be suppressed.

A cross-sectional view of a fuel cell stack centered on a single cell having the separator for the first embodiment of the fuel cell separator. Sectional drawing of the separator for a fuel cell of the same embodiment. Sectional drawing of the extrusion molding machine of the same embodiment. Sectional drawing of the plate material of the same embodiment. The cross-sectional view which shows the state which the 2nd carbon material is arranged on the plate material of the same embodiment. Sectional drawing of the press apparatus of the same embodiment. FIG. 5 is a cross-sectional view of the fuel cell separator of the second embodiment. The cross-sectional view which shows the state which the 2nd carbon material is arranged on the plate material of the same embodiment.

<First Embodiment>
Hereinafter, the first embodiment of the fuel cell separator and the method for manufacturing the fuel cell separator will be described with reference to FIGS. 1 to 6.

In each drawing, a part of the configuration may be exaggerated or simplified for convenience of explanation. In addition, the dimensional ratio of each part may differ from the actual one.
As shown in FIG. 1, the fuel cell separator of the present embodiment (hereinafter, referred to as a separator 20) is used for the stack 100 of the polymer electrolyte fuel cell. The separator 20 is a general term for the first separator 30 and the second separator 40, which will be described later.

The stack 100 has a structure in which a plurality of single cells 10 are stacked. The single cell 10 includes a power generation unit 11 sandwiched between a first separator 30 on the anode side and a second separator 40 on the cathode side.

The power generation unit 11 is composed of a membrane electrode assembly 12, an anode-side gas diffusion layer 15 and a cathode-side gas diffusion layer 16 that sandwich the membrane electrode assembly 12. The anode-side gas diffusion layer 15 is provided between the membrane electrode assembly 12 and the first separator 30. The cathode side gas diffusion layer 16 is provided between the membrane electrode assembly 12 and the second separator 40. Both the anode-side gas diffusion layer 15 and the cathode-side gas diffusion layer 16 are formed of carbon fibers.

The membrane electrode assembly 12 includes an electrolyte membrane 13 made of a solid polymer material having good proton conductivity in a wet state, and a pair of electrode catalyst layers 14 sandwiching the electrolyte membrane 13. A catalyst such as platinum is supported on each electrode catalyst layer 14 in order to promote the electrochemical reaction of the reaction gas in the fuel cell.

The first separator 30 is a gas that extends along the ridges 31 and flows a reaction gas between a plurality of ridges 31 that extend in parallel at intervals from each other and two ridges 31 that are adjacent to each other. It has a flow path 32. Each ridge 31 is in contact with the anode-side gas diffusion layer 15. The ridge 31 and the gas flow path 32 extend in a direction orthogonal to the paper surface of FIG.

The second separator 40 is a gas that extends along the ridges 41 and flows between the plurality of ridges 41 that extend in parallel at intervals from each other and the two ridges 41 that are adjacent to each other. It has a flow path 42. Each ridge 41 is in contact with the cathode side gas diffusion layer 16. The ridge 41 and the gas flow path 42 extend in a direction orthogonal to the paper surface of FIG.

A fuel gas flow path through which fuel gas as a reaction gas flows is formed in a portion of the first separator 30 partitioned by the gas flow path 32 and the anode-side gas diffusion layer 15. An oxidation gas flow path through which an oxidation gas as a reaction gas flows is formed in a portion of the second separator 40 partitioned by the gas flow path 42 and the cathode side gas diffusion layer 16. In the present embodiment, the fuel gas flowing through the fuel gas flow path is hydrogen, and the oxidation gas flowing through the oxidation gas flow path is air.

A cooling water flow path through which cooling water flows is formed in a portion partitioned by the back surface of the ridge 31 of the first separator 30 and the back surface of the ridge 41 of the second separator 40.
As shown in FIG. 2, the separator 20 includes a plate-shaped base material 21. The base material 21 contains a conductive first carbon material 51, contains a first conductive layer 50 formed in the resin material 52, and a conductive second carbon material 61, and has a thickness of the first conductive layer 50. It is provided with second conductive layers 60 formed on both sides in the direction. The second conductive layer 60 is formed adjacent to the first conductive layer 50, and is bonded to the first conductive layer 50 via the resin material 52.

Examples of the first carbon material 51 include natural graphite such as spheroidal graphite. Examples of the resin material 52 include thermoplastic resins such as polypropylene resin. Examples of the second carbon material 61 include natural graphite such as expanded graphite.

Next, a method for manufacturing the separator 20 will be described.
As shown in FIG. 3, first, a plate material P is formed from a mixture in which the first carbon material 51 is dispersed in the resin material 52 by using an extrusion molding machine 200 (plate material forming step).

Here, the extrusion molding machine 200 will be described.
The extrusion molding machine 200 has a cylinder 201, a screw 202 housed in the cylinder 201, a first hopper 203 for supplying the resin material 52 in the cylinder 201, and a first carbon material 51 for supplying the first carbon material 51 in the cylinder 201. It is equipped with 2 hoppers 204. The second hopper 204 is provided on the tip end side of the cylinder 201 with respect to the first hopper 203.

A die 205 having a discharge port 205a is provided at the tip of the cylinder 201. Further, a heater 206 for heating the inside of the cylinder 201 is provided on the outer peripheral portion of the cylinder 201.

The screw 202 is connected to a drive device 207 having a motor (not shown) and is rotatably provided in the cylinder 201. By rotating the screw 202, the resin material 52 supplied from the first hopper 203 and the first carbon material 51 supplied from the second hopper 204 are mixed, and a mixture thereof is brought to the tip of the cylinder 201. It is transported toward. At this time, the resin material 52 is melted by being heated by the heater 206.

The plate material P is formed by extruding the mixture of the first carbon material 51 and the resin material 52 from the discharge port 205a of the die 205. The plate material P is cut into a predetermined shape by a cutting device (not shown).

As shown in FIG. 4, in the plate material P, the first carbon material 51 is dispersed in the resin material 52 over the entire thickness direction.
As shown in FIG. 5, next, the second carbon material 61 is arranged on both side surfaces of the plate material P in the thickness direction (second carbon material arrangement step). In the present embodiment, the powder of the second carbon material 61 is adhered to both side surfaces of the plate material P.

As shown in FIG. 6, next, by using the press device 300 to heat and pressurize the plate material P on which the second carbon material 61 is arranged, the first conductivity is formed in the central portion of the plate material P in the thickness direction. The layer 50 is formed, and the second conductive layer 60 is formed adjacent to the first conductive layer 50 on both sides of the plate material P in the thickness direction (conductive layer forming step).

Here, the press device 300 will be described.
The press device 300 includes a lower die 301 and an upper die 305 provided so as to be able to advance and retreat with respect to the lower die 301.

At the center of the lower mold 301, a protruding portion 302 protruding toward the upper mold 305 is provided. The protrusion 302 is provided with a die 303 for forming the ridges 31, 41 and the gas flow paths 32, 42 on the plate material P. A heating wire 304 is built in the lower mold 301.

At the center of the upper mold 305, a protruding portion 306 protruding toward the lower mold 301 is provided. The protrusion 306 is provided with punches 307 for forming the ridges 31, 41 and the gas flow paths 32, 42 on the plate material P. The punch 307 and the die 303 are provided so as to face each other. A heating wire 308 is built in the upper mold 305.

Next, the lower mold 301 and the upper mold 305 are heated to a predetermined temperature by supplying an electric current to the heating wires 304 and 308. After that, the plate material P on which the second carbon material 61 is arranged is placed on the die 303 of the lower mold 301, and the plate material P is sandwiched between the lower mold 301 and the upper mold 305. As a result, the plate material P is heated and softened.

Next, the plate material P is pressurized by the lower mold 301 and the upper mold 305. As a result, the plate material P is deformed according to the shapes of the die 303 and the punch 307. After that, when the plate material P is cooled, the resin material 52 is cured to form the first conductive layer 50 and the second conductive layer 60. At this time, the ridges 31, 41 and the gas flow paths 32, 42 are formed on the plate material P.

In this way, the separator 20 is manufactured.
The operation of this embodiment will be described.
The first conductive layer 50 and the second conductive layer 60 constituting the separator 20 come into contact with each other in the thickness direction. As a result, a conductive path is formed inside the separator 20 via the first conductive layer 50 and the second conductive layer 60. Further, on the surface of the separator 20 on which the second conductive layer 60 is formed, it is suppressed that the ratio of the resin material 52 is larger than that of the other portions.

The effect of this embodiment will be described.
(1) The separator 20 includes a base material 21. The base material 21 contains the first carbon material 51, contains the first conductive layer 50 formed in the resin material 52, and the second carbon material 61, and is on at least one side of the first conductive layer 50 in the thickness direction. It includes a second conductive layer 60 formed adjacent to the first conductive layer 50 and bonded to the first conductive layer 50 via a resin material 52.

According to such a configuration, since the above-mentioned action is obtained, an increase in the contact resistance of the separator 20 can be suppressed.
(2) The second conductive layer 60 is formed on both sides of the first conductive layer 50 in the thickness direction.

According to such a configuration, the conductive paths are formed on both sides of the first conductive layer 50 in the thickness direction. Further, it is suppressed that the ratio of the resin material 52 on both sides of the separator 20 is larger than that of the other portions. Therefore, an increase in the contact resistance of the separator 20 can be further suppressed.

(3) In the plate material forming step, the plate material P is formed from a mixture in which the first carbon material 51 is dispersed in the resin material 52. In the second carbon material arranging step, the second carbon material 61 is arranged on at least one surface of the plate material P in the thickness direction. In the conductive layer forming step, the plate material P on which the second carbon material 61 is arranged is heated and pressurized to form the first conductive layer 50 including the first carbon material 51 in the central portion in the thickness direction of the plate material P. At the same time, a second conductive layer 60 containing the second carbon material 61 is formed adjacent to the first conductive layer 50 on one side of the plate material P.

According to such a method, in the conductive layer forming step, the plate material P on which the second carbon material 61 is arranged is heated and pressurized, so that the first carbon material 51 dispersed in the resin material 52 is in the thickness direction. It becomes unevenly distributed in the central part. On the other hand, a second conductive layer 60 is formed adjacent to the first conductive layer 50 via the resin material 52 in the vicinity of at least one surface of the plate material P in the thickness direction. Therefore, on the surface of the separator 20 on which the second conductive layer 60 is formed, it is suppressed that the ratio of the resin material 52 is higher than that of the other portions.

(4) In the second carbon material arranging step, the second carbon material 61 is arranged on both side surfaces of the plate material P in the thickness direction. In the conductive layer forming step, the second conductive layer 60 is formed on both sides of the plate material P in the thickness direction.

According to such a method, an effect similar to the above-mentioned effect (2) can be obtained.
<Second Embodiment>
Hereinafter, the second embodiment of the method for manufacturing the fuel cell separator and the fuel cell separator will be described with reference to FIGS. 7 and 8, focusing on the differences from the first embodiment.

In each drawing, a part of the configuration may be exaggerated or simplified for convenience of explanation. In addition, the dimensional ratio of each part may differ from the actual one.
Regarding the configurations of the second embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and the configurations corresponding to the first embodiment are designated by the reference numerals “**” of the first embodiment as “**”. By adding the code "1 **" to which "100" is added, the duplicate description may be omitted.

As shown in FIG. 7, the separator 120 includes a plate-shaped base material 121. The base material 121 contains the conductive first carbon material 51, contains the first conductive layer 50 formed in the resin material 52, and the conductive second carbon material 161. The thickness of the first conductive layer 50. It is provided with second conductive layers 160 formed on both sides in the direction. Each second conductive layer 160 constitutes the surface of the base material 121, that is, the surface of the separator 120.

Examples of the first carbon material 51 include natural graphite such as spheroidal graphite. Examples of the resin material 52 include thermoplastic resins such as polyether sulfone (PES).

The second carbon material 161 constituting the second conductive layer 160 includes first carbon particles 162 and second carbon particles 163 having an average particle size smaller than the average particle size of the first carbon particles 162.

The "average particle size" in the present specification refers to the particle size when the integrated value in the volume-based particle size distribution measured by a laser diffraction / scattering method or the like is 50%, that is, the median size. In each figure, for convenience, the carbon particles having the median diameter of the first carbon particles 162 of the first carbon particles 162 and the median diameter of the second carbon particles 163 of the second carbon particles 163 are shown. The carbon particles having are shown in the figure.

Examples of the first carbon particles 162 include natural graphite such as spheroidal graphite. Examples of the second carbon particles 163 include artificial graphite. The first carbon material 51 of the first conductive layer 50 and the first carbon particles 162 of the second conductive layer 160 in the present embodiment are the same type of carbon material.

Each of the second conductive layers 160 is bonded to the first conductive layer 50 via the resin material 52 of the first conductive layer 50. On the surface of each of the second conductive layers 160, the first carbon particles 162 and the second carbon particles 163 are exposed from the resin material 52. More specifically, the surface of each second conductive layer 160 is composed of only the second carbon material 161. Therefore, the resin material 52 is not exposed on the surface of each of the second conductive layers 160. In other words, the entire resin material 52 is covered with the second carbon material 161 on both sides of the separator 120 in the thickness direction.

From the above, in the second conductive layer 160 facing the power generation unit 11, the first carbon particles 162 and the second carbon particles 163 contained in the second conductive layer 160 are in contact with the power generation unit 11.

Next, a method of manufacturing the separator 120 will be described. In the method for manufacturing the separator 120, the second carbon material arranging step is different from the method for manufacturing the separator 20 of the first embodiment.
As shown in FIG. 8, in the second carbon material arranging step, the second carbon material 161 is arranged on the entire surfaces on both sides of the plate material P in the thickness direction. In the present embodiment, an amount of the second carbon material 161 that is more than the amount of the second carbon material 161 required to cover the entire resin material 52 in the second conductive layer 160 is applied in the thickness direction of the plate material P. Adhere to both sides. Therefore, the entire surfaces on both sides of the plate material P in the thickness direction are covered with the second carbon material 161.

In the conductive layer forming step, the second conductive layer 160 is formed adjacent to the first conductive layer 50 on both sides of the plate material P in the thickness direction. At this time, the second carbon material 161 is bonded to the first conductive layer 50 via the resin material 52 of the first conductive layer 50. As described above, since an excessive amount of the second carbon material 161 is attached to the plate material P, a part of the second carbon material 161 does not bond with the first conductive layer 50 and is second conductive. It remains on the surface of layer 160. In the present embodiment, after the second carbon material arranging step, a step of removing the second carbon material 161 remaining on the surface of the second conductive layer 160 is performed.

The operation of this embodiment will be described.
In the power generation unit 11, water is generated by the electrochemical reaction of the reaction gas. The water thus generated (hereinafter referred to as generated water) is discharged to the outside of the power generation unit 11 through the gas flow path 42 by the pressure of the reaction gas. However, when the amount of produced water is large, the pressure loss of the reaction gas may increase excessively. Therefore, it is preferable that the generated water is discharged to the outside of the power generation unit 11 at an early stage.

According to the above configuration, the surface of the second conductive layer 160 formed on both sides of the first conductive layer 50 in the thickness direction is formed by the second carbon material 161 containing the first carbon particles 162 and the second carbon particles 163. , Many fine irregularities are formed. As a result, the surface of the separator 120 on which the second conductive layer 160 is formed is brought into contact with the power generation unit 11, so that the generated water generated in the power generation unit 11 travels through a large number of fine irregularities to the second conductive layer 160. It becomes easy to be discharged from the surface of.

The effect of this embodiment will be described.
According to the present embodiment, in addition to the effects (1) to (4) in the first embodiment, the following effects can be newly obtained.

(5) The second carbon material 161 of the second conductive layer 160 includes first carbon particles 162 and second carbon particles 163 having an average particle size smaller than the average particle size of the first carbon particles 162. The surface of the second conductive layer 160 is composed of only the second carbon material 161.

According to such a configuration, since the above-mentioned action is exhibited, the dischargeability of the produced water can be enhanced.
Further, according to the above configuration, the surface of the second conductive layer 160 is composed of only the second carbon material 161. That is, the resin material 52 of the first conductive layer 50 is not exposed on the surfaces on both sides of the separator 120 in the thickness direction. Therefore, an increase in the contact resistance of the separator 120 can be suppressed.

(6) In the second carbon material arranging step, the second carbon material 161 is arranged on the entire surfaces on both sides of the plate material P in the thickness direction. As the second carbon material 161, a material containing first carbon particles 162 and second carbon particles 163 having an average particle size smaller than the average particle size of the first carbon particles 162 is used.

According to such a method, in the second carbon material arranging step, the entire surfaces on both sides of the plate material P in the thickness direction are covered with the second carbon material 161 including the first carbon particles 162 and the second carbon particles 163. .. As a result, the surfaces of the second conductive layer 160 formed on both sides of the plate material P in the thickness direction in the conductive layer forming step are likely to be formed only by the second carbon material 161. That is, the resin material 52 is less likely to be exposed from the surfaces on both sides of the separator 120 in the thickness direction. According to the separator 120 produced in this way, since the effect according to the above effect (5) is exhibited, the dischargeability of the produced water can be enhanced. In addition, an increase in the contact resistance of the separator 120 can be suppressed.

<Change example>
Each of the above embodiments can be modified and implemented as follows. Each of the above embodiments and the following modified examples can be implemented in combination with each other within a technically consistent range.

In the plate material forming step of each of the above embodiments, a mixture in which the first carbon material 51 and the resin material 52 are mixed in advance may be supplied into the cylinder 201 of the extrusion molding machine 200.
In the plate material forming step of each of the above embodiments, the mixture of the first carbon material 51 and the resin material 52 is heated by using a belt press machine provided with a pair of belts facing each other instead of the extrusion molding machine 200. The plate material P may be formed by pressurizing.

-In the second carbon material arranging step of each of the above-described embodiments, the powders of the second carbon materials 61 and 161 may be sprinkled on the surface of the die 303 of the lower mold 301. In this case, when the plate material P is pressed by the die 303 and the punch 307, the powders of the second carbon materials 61 and 161 adhere to the resin material 52 on the surface of the plate material P facing the die 303.

-In the second carbon material arranging step of the first embodiment, a paint containing the powder of the second carbon material 61 and the resin material as a binder is applied to the surface of the plate material P by, for example, a coater or a spray. You may do it. The second conductive layer 60 of the separator 20 manufactured by such a method contains the second carbon material 61 and the resin material. At this time, the resin material 52 contained in the first conductive layer 50 and the resin material contained in the second conductive layer 60 may be the same resin material or different resin materials from each other. ..

-In each of the above embodiments, the second conductive layers 60 and 160 may be formed only on one surface of the first conductive layer 50 in the thickness direction. In this case, in the second carbon material arranging step, the second carbon materials 61 and 161 may be arranged only on one surface of the plate material P in the thickness direction.

The second conductive layers 60 and 160 of each of the above embodiments are preferably formed on the entire surface of the portions of the separators 20 and 120 facing the power generation unit 11, but are not necessarily formed on the entire surface. May be good. For example, the second conductive layers 60 and 160 may be formed only on the top surfaces of the ridges 31 and 41 of the separators 20 and 120.

-In the first embodiment, the resin material 52 may be a thermoplastic resin other than polypropylene resin.
-In the second embodiment, the resin material 52 may be a thermoplastic resin other than the polyether sulfone.

-In each of the above embodiments, the resin material 52 may be a thermosetting resin such as an epoxy resin.
-In the first embodiment, the first carbon material 51 and the second carbon material 61 are different carbon materials from each other, but these may be the same carbon material.

-In the first embodiment, the first carbon material 51 may be any conductive carbon material, and may be, for example, artificial graphite, natural graphite other than spheroidal graphite, or the like. The second carbon material 61 may be any conductive carbon material, and may be, for example, artificial graphite, natural graphite other than expanded graphite, or the like.

-In each of the above embodiments, the first conductive layer 50 may contain, in addition to the first carbon material 51, a carbon material different from the first carbon material 51, conductive particles made of metal, or the like. .. In addition to the second carbon materials 61 and 161, the second conductive layers 60 and 160 may contain a carbon material different from the second carbon materials 61 and 161, conductive particles made of metal, and the like.

-In the second embodiment, the first carbon material 51 of the first conductive layer 50 and the first carbon particles 162 of the second conductive layer 160 are the same type of carbon material, but these are different types of carbon. It may be a material.

-In the second embodiment, the first carbon particles 162 and the second carbon particles 163 may be the same type of carbon material.
-In each of the above embodiments, the separators 20 and 120 may be applied only to the first separator 30 on the anode side, or may be applied only to the second separator 40 on the cathode side.

P ... Plate material 20, 120 ... Separator 21, 121 ... Base material 50 ... First conductive layer 51 ... First carbon material 52 ... Resin material 60, 160 ... Second conductive layer 61, 161 ... Second carbon material 162 ... First Carbon particles 163 ... Second carbon particles

Claims (6)

A fuel cell separator equipped with a base material.
The base material is
A first conductive layer containing a conductive first carbon material and formed in the resin material,
It contains a conductive second carbon material, is formed adjacent to the first conductive layer on at least one side in the thickness direction of the first conductive layer, and is bonded to the first conductive layer via the resin material. The second conductive layer is provided.
Separator for fuel cells. The second conductive layer is formed on both sides of the first conductive layer in the thickness direction.
The fuel cell separator according to claim 1. The second carbon material constituting the second conductive layer bonded to the one side of the first conductive layer has the first carbon particles and an average particle size smaller than the average particle size of the first carbon particles. Containing with the second carbon particles having
The surface of the second conductive layer is composed of only the second carbon material.
The fuel cell separator according to claim 1 or 2. It is a method of manufacturing a separator for a fuel cell.
A plate material forming step of forming a plate material from a mixture in which a conductive first carbon material is dispersed in a resin material, and
A second carbon material arranging step of arranging a conductive second carbon material on at least one surface in the thickness direction of the plate material, and
By heating and pressurizing the plate material on which the second carbon material is arranged, a first conductive layer containing the first carbon material is formed in the central portion in the thickness direction of the plate material, and the plate material in the plate material. A conductive layer forming step of forming a second conductive layer containing the second carbon material on one side adjacent to the first conductive layer is provided.
A method for manufacturing a separator for a fuel cell. In the second carbon material arranging step, the second carbon material is arranged on both side surfaces in the thickness direction of the plate material.
In the conductive layer forming step, the second conductive layer is formed on both sides of the plate material.
The method for manufacturing a fuel cell separator according to claim 4. In the second carbon material arranging step, the second carbon material is arranged on the entire surface of the plate material on the one side.
As the second carbon material, a material containing first carbon particles and second carbon particles having an average particle size smaller than the average particle size of the first carbon particles is used.
The method for manufacturing a fuel cell separator according to claim 4 or 5.

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