阅读说明：本技术 燃料电池用隔板的制造方法 (Method for manufacturing separator for fuel cell ) 是由 野畑安浩 于 2020-02-04 设计创作，主要内容包括：本发明提供能够实现轻型化且能够抑制成形时的不良状况的燃料电池用隔板的制造方法。该燃料电池用隔板的制造方法(M)成形具有划分出流体的流路的流路部和在该流路部的周缘部密封流体的密封部的隔板。制造方法(M)具有：埋设工序(S1),将线材埋设于含有导电性粒子的未固化的热固化性树脂；以及成形工序(S4),使埋设了线材的热固化性树脂在模具的内部固化来成形隔板。(The invention provides a method for manufacturing a fuel cell separator, which can realize weight reduction and can inhibit bad conditions during forming. The method (M) for producing a fuel cell separator forms a separator having a flow path portion that defines a flow path for a fluid and a seal portion that seals the fluid at a peripheral edge portion of the flow path portion. The manufacturing method (M) comprises: an embedding step (S1) for embedding the wire material in an uncured thermosetting resin containing conductive particles; and a molding step (S4) in which the separator is molded by curing the thermosetting resin in which the wire material is embedded inside the mold.)

1. A method for manufacturing a separator for a fuel cell, comprising forming a separator having a flow path portion defining a flow path of a fluid and a seal portion for sealing the fluid at a peripheral edge portion of the flow path portion,

the method for manufacturing a separator for a fuel cell is characterized by comprising:

an embedding step of embedding a wire in an uncured thermosetting resin containing conductive particles; and

and a molding step of curing the thermosetting resin in which the wire material is embedded in a mold to mold the separator.

2. The method of manufacturing a separator for a fuel cell according to claim 1,

in the embedding step, the wires woven in a mesh shape are embedded in the thermosetting resin.

3. The method of manufacturing a separator for a fuel cell according to claim 2,

after the embedding step and before the forming step, the method includes:

a pre-curing step of pre-curing the thermosetting resin; and

and a conveying step of conveying the thermosetting resin, in which the wire material is embedded and pre-cured, to the mold.

4. The method of manufacturing a separator for a fuel cell according to claim 1,

the conductive particles are carbon particles, and the conductive particles are carbon particles,

in the embedding step, the volume ratio of the carbon particles contained in the thermosetting resin disposed in the region corresponding to the flow path portion is set to 65% or more and 75% or less.

5. The method of manufacturing a separator for a fuel cell according to claim 4,

in the embedding step, the volume ratio of the carbon particles contained in the thermosetting resin disposed in the region corresponding to the sealing portion is 20% or less.

Technical Field

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

Background

Conventionally, an invention related to a press forming method of a metal plate is known (see patent document 1 below). The problem of the conventional press forming method is to solve the problem generated in the press forming of the separator for the fuel cell. Specifically, the problem is that: since the projected portions of the primary forming mold have an R-shape (a shape having a curved top portion), the top surface of the projected portions of the material sheet after primary forming is curved, and it is difficult to restore the curved top surface to a flat surface during secondary forming (see paragraphs 0002 to 0004 and the like of the document).

In order to solve the above problem, the conventional press-forming method of a metal plate includes a first press step and a second press step (see claim 1 and the like of the same document). In the first pressing step, the metal plate is press-formed using a first temporary forming die and a second temporary forming die for temporary forming, thereby obtaining a temporarily formed metal plate having projections and recesses extending in a stripe shape. In the second press step, the temporarily formed metal plate is further press-formed using a first main forming die and a second main forming die for main forming.

According to this conventional press-forming method of a metal plate, in the first press step as the provisional forming, the flat top portion of the first convex portion of the first provisional forming die is brought into contact with the metal plate and presses the metal plate. Therefore, the top surface (convex surface) of the convex portion of the metal plate after the temporary forming can be made flat as compared with the case where the convex portion of the mold is formed in the R shape. In the second pressing step, which is the primary forming, the metal plate is brought into contact with the flat bottom portion of the second concave portion of the second primary forming die. Therefore, the top surface of the convex portion of the metal plate after the final forming can be made flat (see the 0006 th to 0007 th paragraphs and the like of the document).

Patent document 1: japanese laid-open patent publication No. 2018-094579

The fuel cell separator is required to be further lightweight. Therefore, the use of a resin as a material for a fuel cell separator is being investigated. When a thermosetting resin is used as the resin constituting the fuel cell separator, for example, a core material that stabilizes the shape of the uncured thermosetting resin is required. As such a core material, a sheet material such as a metal foil that is significantly thinner than the metal plate used in the above-described conventional press forming method can be used.

However, when the uncured thermosetting resin having the thin sheet as the core material is cured and molded in the mold, the flow of the thermosetting resin is disturbed in the mold, and there is a possibility that defects such as wrinkles, cracks, and a local reduction in thickness occur.

Disclosure of Invention

Provided is a method for manufacturing a fuel cell separator, wherein weight reduction can be achieved and defects during molding can be suppressed.

One aspect of the present disclosure is a method for manufacturing a separator for a fuel cell, the method comprising forming a separator having a flow path portion defining a flow path of a fluid and a seal portion for sealing the fluid at a peripheral edge portion of the flow path portion, the method comprising: an embedding step of embedding a wire in an uncured thermosetting resin containing conductive particles; and a molding step of curing the thermosetting resin in which the wire is embedded in a mold to mold the separator.

The method for manufacturing the fuel cell separator according to the above aspect may include: in the embedding step, the wires woven in a mesh shape are embedded in the thermosetting resin.

The method for manufacturing the fuel cell separator according to the above aspect may include: after the embedding step and before the forming step, the method includes: a precuring step of precuring the thermosetting resin; and a conveying step of conveying the thermosetting resin, in which the wire material is embedded and pre-cured, to the mold.

In the method of manufacturing a fuel cell separator of the above aspect, the method may include: the conductive particles are carbon particles, and in the embedding step, the volume ratio of the carbon particles contained in the thermosetting resin disposed in a region corresponding to the flow path portion is set to 65% or more and 75% or less.

The method for manufacturing the fuel cell separator according to the above aspect may include: in the embedding step, the volume ratio of the carbon particles contained in the thermosetting resin disposed in the region corresponding to the sealing portion is 20% or less.

According to the present disclosure, it is possible to provide a method for manufacturing a fuel cell separator, which can reduce the weight and suppress a problem during molding.

Drawings

Fig. 1 is a plan view showing an example of the structure of a fuel cell unit.

Fig. 2 is an enlarged cross-sectional view showing a main part of a fuel cell stack in which the fuel cell units shown in fig. 1 are stacked.

Fig. 3 is a flowchart of a method for manufacturing a fuel cell separator according to an embodiment of the present disclosure.

Fig. 4 is a plan view of the uncured thermosetting resin after the burying step shown in fig. 3 is completed.

FIG. 5 is an enlarged cross-sectional view taken along line V-V of the uncured thermosetting resin shown in FIG. 4.

Fig. 6 is a schematic view showing the states of the thermosetting resin and the mold after the end of the conveying step shown in fig. 3.

Description of reference numerals:

3: a partition plate; 3 a: a thermosetting resin; 21: a flow path; 22: a flow path; 23: a flow path; 31: a flow path section; 31 a: a thermosetting resin; 32: a sealing part; 32 a: a thermosetting resin; 33: a wire rod; 34: conductive particles; d: a mold; m: a method for producing a separator for a fuel cell; s1: burying; s2: a pre-curing process; s3: a conveying step; s4: and (5) forming.

Detailed Description

Hereinafter, an embodiment of a method for manufacturing a fuel cell separator according to the present disclosure will be described with reference to the drawings. Hereinafter, first, an example of the structure of a fuel cell unit and a fuel cell stack including a fuel cell separator will be described, and then, an embodiment of a method for manufacturing a fuel cell separator according to the present disclosure will be described

Fig. 1 is a plan view of a fuel cell unit (hereinafter, simply referred to as "unit 1"). Fig. 2 is an enlarged cross-sectional view of a main portion of a fuel cell stack (hereinafter, simply referred to as "stack 10") configured by stacking the cells 1 shown in fig. 1. The cell 1 is, for example, a polymer electrolyte fuel cell that generates an electromotive force by an electrochemical reaction between an oxidant gas such as air and a fuel gas such as hydrogen. The cell 1 includes a membrane-electrode-gas diffusion layer assembly (hereinafter, abbreviated as "MEGA 2") and a separator 3 that is in contact with the MEGA2 so as to divide the MEGA 2.

The MEGA2 is a power generation unit of the cell 1 that generates electromotive force by electrochemical reaction. The MEGA2 is sandwiched between a pair of separators 3, 3. The MEGA2 has a structure in which a membrane-electrode assembly (hereinafter, simply referred to as "MEA 4") and gas diffusion layers 7 and 7 disposed on both surfaces of the MEA4 are integrated.

The MEA4 includes an electrolyte membrane 5 and a pair of electrodes 6 and 6 joined to sandwich the electrolyte membrane 5. The electrolyte membrane 5 is constituted by a proton-conductive ion-exchange membrane made of a solid polymer material. In the case where the cell 1 does not have the gas diffusion layer 7, the MEA4 serves as the power generation unit of the cell 1.

The electrode 6 is made of, for example, a porous carbon material on which a catalyst such as platinum is supported. The electrode 6 disposed on one side of the electrolyte membrane 5 serves as an anode, and the electrode 6 on the other side serves as a cathode. Two adjacent cells 1 in the group 10 are arranged so that the electrode 6 that becomes an anode and the electrode 6 that becomes a cathode face each other.

The gas diffusion layer 7 is made of a gas-permeable conductive member such as a carbon porous body such as carbon paper or carbon cloth, or a metal porous body such as a metal mesh or foamed metal.

The separator 3 is a plate-like member made of a conductive resin, and is manufactured by a method M (see fig. 3) for manufacturing a fuel cell separator, which will be described later. The separator 3 has a structure in which wires 33 are embedded in a thermosetting resin 3a containing conductive particles 34 (see fig. 4 and 5). As the conductive particles 34, for example, carbon particles can be used. As the wire 33, for example, a metal wire such as stainless steel (SUS) or titanium, a resin wire such as rayon, or an inorganic wire such as glass fiber can be used. As the thermosetting resin 3a, for example, an epoxy resin or a phenol resin can be used.

As shown in fig. 1 and 2, the separator 3 includes a flow path portion 31 that defines the flow paths 21, 22, and 23 of the fluid, and a seal portion 32 that seals the fluid at a peripheral edge portion of the flow path portion 31. In fig. 1, the flow paths 21 and 23 on the front side of the unit 1 are shown, and the flow paths 22 and 23 on the back side of the unit 1 are not shown.

The flow path portion 31 of the separator 3 has a waveform or a concavo-convex shape in a cross section as shown in fig. 2, for example, and a plurality of stripe-shaped flow paths 21, 22, 23 extending in the longitudinal direction of the cell 1 shown in fig. 1 are formed so as to extend longitudinally through the power generation portion. In the flow path portion 31, the pair of separators 3, 3 of each cell 1 has an inner surface facing the MEGA2 in contact with the gas diffusion layer 7, and an outer surface opposite to the MEGA2 in contact with an outer surface of the separator 3 of another adjacent cell 1.

Thus, in the pair of separators 3, 3 of each cell 1, the anode-side separator 3 defines the fuel gas flow path 21 between itself and the MEGA2, and the cathode-side separator 3 defines the oxidant gas flow path 22 between itself and the MEGA 2. In the adjacent two cells 1, the outer surface of the anode-side separator 3 of one cell 1 is in contact with the outer surface of the cathode-side separator 3 of the other cell 1. This divides the flow path 23 of the refrigerant between the two adjacent units 1.

More specifically, each separator 3 has an isosceles trapezoid shape in which the top of the waveform is substantially flat, and has angular portions having equal-angle corners at both ends of the top. That is, each separator 3 has substantially the same shape when viewed from the inside facing the MEGA2 or the outside opposite to the MEGA 2. In the pair of separators 3, 3 of each cell 1, the corrugated top of the anode-side separator 3 is in surface contact with the anode-side gas diffusion layer 7 of the MEGA2, and the corrugated top of the cathode-side separator 3 is in surface contact with the cathode-side gas diffusion layer 7 of the MEGA 2.

As shown in fig. 1, the sealing portion 32 of the separator 3 seals the peripheral edge portions of the flow path portions 31 of the pair of separators 3, 3 of each unit 1, thereby preventing leakage of the gas flowing through the flow paths 21, 22 formed inside the pair of separators 3, 3. More specifically, the seal portion 32 is, for example, a portion where the pair of separators 3, 3 are in close contact with each other, and includes a seal member that seals a fluid between the pair of separators 3, 3.

The seal portion 32 is provided with manifold holes 21a and 21b communicating with the anode-side flow path 21 between the pair of separators 3 and 3, and manifold holes 22a and 22b communicating with the cathode-side flow path 22 between the pair of separators 3 and 3. The seal portion 32 is provided with manifold holes 23a and 23b for supplying and discharging the refrigerant to and from the flow paths 23 outside the pair of separators 3 and 3.

With this configuration, when the fuel gas is supplied to the anode-side flow path 21 of the MEGA2 and the oxidant gas is supplied to the cathode-side flow path 22 of the MEGA2, the electrochemical reaction occurs in the MEGA2 in each cell 1, and electromotive force is generated. The group 10 takes out electromotive force generated in the plurality of cells 1 at both ends of the stacked plurality of cells 1 and supplies the electromotive force to the outside. In the group 10, each cell 1 generates heat due to power generation, but is cooled by a coolant such as cooling water flowing through the flow path 23 between the adjacent cells 1, 1.

Next, an embodiment of a method for manufacturing a fuel cell separator according to the present disclosure will be described with reference to fig. 3. Fig. 3 is a flowchart showing an example of the steps of the method M for manufacturing a fuel cell separator according to the present embodiment. As will be described in detail later, the main features of the method M for manufacturing a fuel cell separator according to the present embodiment are as follows.

For example, as shown in fig. 1 and 2, a method M for manufacturing a fuel cell separator according to the present embodiment is a method for molding a separator 3 having a flow path portion 31 for partitioning fluid flow paths 21, 22, and 23, and a seal portion 32 for sealing the fluid at the peripheral edge portion of the flow path portion 31. The method M for manufacturing a separator for a fuel cell includes: an embedding step S1 of embedding the wire 33 in the uncured thermosetting resin 3a containing the conductive particles 34 (see fig. 4 and 5); in the molding step S4, the thermosetting resin 3a in which the wires 33 are embedded is cured inside a mold D (fig. 6) to mold the separator 3. Hereinafter, the method M for manufacturing the fuel cell separator of the present embodiment will be described in detail.

In the example shown in fig. 3, the method M for manufacturing a fuel cell separator includes the pre-curing step (temporary curing step) S2 and the transporting step S3 in addition to the embedding step S1 and the forming step S4.

Fig. 4 is a plan view of uncured thermosetting resin 3a in which wire members 33 are embedded in embedding step S1. Fig. 5 is an enlarged cross-sectional view taken along line V-V of uncured thermosetting resin 3a shown in fig. 4. The embedding step S1 is a step of embedding the wire rod 33 in the uncured thermosetting resin 3a containing the conductive particles 34 as described above. Specifically, embedding step S1 includes, for example, a first coating step, a second coating step, a wire arranging step, a third coating step, and a fourth coating step.

The first coating step is a step of applying, for example, uncured thermosetting resin 32a for forming the sealing portion 32 of the separator 3 shown in fig. 1 onto the supporting base material. Specifically, first, a paste-like uncured thermosetting resin 32a in which conductive particles 34 are kneaded is prepared. As described above, for example, carbon particles can be used as the conductive particles 34, and for example, epoxy resin or phenol resin can be used as the thermosetting resin 32 a. In the embedding step S1, the volume ratio of the carbon particles contained in the thermosetting resin 32a disposed in the region corresponding to the sealing portion 32 of the separator 3 shown in fig. 1 is preferably 20% or less.

Next, the uncured thermosetting resin 32a containing the conductive particles 34 is applied to the supporting base material by an appropriate application device such as a die coater. At this time, the uncured thermosetting resin 32a is applied in a rectangular frame shape corresponding to the shape of the sealing portion 32 shown in fig. 1. Thereby, the first coating process is ended.

After the first coating step is completed, the second coating step is performed. The second coating step is a step of applying an uncured thermosetting resin 31a for forming the flow path portion 31 of the separator 3 shown in fig. 1 onto the supporting base material. Specifically, first, a paste-like uncured thermosetting resin 31a in which conductive particles 34 are kneaded is prepared. As described above, for example, carbon particles can be used as the conductive particles 34, and for example, epoxy resin or phenol resin can be used as the thermosetting resin 31 a. In the embedding step S1, the volume ratio of the carbon particles contained in the thermosetting resin 31a disposed in the region corresponding to the flow path section 31 of the separator 3 shown in fig. 1 is preferably 65% or more and 75% or less.

Next, the uncured thermosetting resin 31a containing the conductive particles 34 is applied to the supporting base material by an appropriate application device such as a die coater. At this time, the thermosetting resin 31a is coated on the inside of the thermosetting resin 32a having a rectangular frame shape in the first coating step, and is coated on the region corresponding to the flow path section 31 shown in fig. 1. Thereby, the second coating process is ended.

In the present embodiment, a method in which the first coating step and the second coating step are sequentially performed in embedding step S1 is described. However, in other embodiments, the first coating step may be performed after the second coating step in burying step S1, or the first coating step and the second coating step may be performed simultaneously.

After the first coating step and the second coating step are completed, the wire rod arranging step is performed. The wire arrangement step is a step of arranging the wires 33 serving as the core material of the separator 3 on the thermosetting resins 31a and 32a coated in the first coating step and the second coating step. As described above, for example, a metal wire such as stainless steel (SUS) or titanium, a resin wire such as rayon, or an inorganic wire such as glass fiber can be used as the wire.

In the thermosetting resin 3a shown in fig. 4, the plurality of wires 33 includes a plurality of parallel wires 33 extending from one end to the other end in the longitudinal direction of the thermosetting resin 3a, and a plurality of parallel wires 33 extending from one end to the other end in the width direction of the thermosetting resin 3 a. That is, in the example shown in fig. 4, in the wire arranging step of the embedding step S1, the plurality of wires 33 are arranged in a state of being woven in a mesh shape on the thermosetting resins 31a, 32a, whereby the plurality of wires 33 are embedded in the thermosetting resin 3 a. In this case, the material of the wires 33 is, for example, a metal wire, the diameter of the wires 33 is, for example, about 50 μm, and the pitch of the wires 33 is, for example, about 2mm to about 3 mm.

The material, diameter, pitch, and arrangement of the wires embedded in thermosetting resin 3a in embedding step S1 are not particularly limited as long as the shape of thermosetting resin 3a can be maintained under predetermined conditions. For example, the thermosetting resin 3a may embed only a plurality of parallel wires 33 extending from one end to the other end in the longitudinal direction, or may embed only a plurality of parallel wires 33 extending from one end to the other end in the width direction. In either case, when the wires 33 are arranged on the thermosetting resins 31a and 32a coated in the first coating step and the second coating step, the wire arrangement step is completed.

After the wire rod arranging step is finished, the third coating step and the fourth coating step are performed. The third coating step is a step of coating the thermosetting resin 32a on which the wires 33 are arranged in the wire arranging step after the coating in the first coating step. The fourth coating step is a step of coating thermosetting resin 31a on which wires 33 are arranged in the wire arranging step, by coating in the second coating step. The third coating step and the fourth coating step can be performed in the same manner as the first coating step and the second coating step described above. As described above, as shown in fig. 4 and 5, thermosetting resin 3a having wires 33 embedded therein and composed of thermosetting resin 31a and thermosetting resin 32a is obtained, and embedding step S1 is completed.

The precuring step S2 is a step of precuring the thermosetting resin 3a after the embedding step S1 and before the molding step S4. Specifically, for example, the process is a step in which thermosetting resin 3a shown in fig. 4 and 5 is heated at a temperature lower than the glass transition temperature in a preheating furnace, and thereby thermosetting resin 3a can be semi-cured to a degree that stabilizes the shape without completely curing it. In addition, when it is not necessary to convey the thermosetting resin 3a after the end of the embedding step S1, or when the shape of the thermosetting resin 3a is stable without precuring, the precuring step S2 can be omitted.

Fig. 6 is a schematic view showing the state of the thermosetting resin 3a and the mold D after the end of the conveying step S3. The conveying step S3 is a step of conveying the thermosetting resin 3a, which is embedded with the wire rods 33 and pre-cured, to the mold D after the embedding step S1 and before the molding step S4. Specifically, the thermosetting resin 3a, which is embedded with the wire 33 and is pre-cured, is conveyed by an appropriate conveying device and is disposed at a predetermined position of the mold D.

The mold D includes, for example, an upper mold D1, a lower mold D2, and a lifter D3. The upper die D1 and the lower die D2 are disposed so as to face each other, for example, so as to be movable in the vertical direction, and form a cavity for molding the flow path portion 31 and the seal portion 32 of the separator 3. The lifter D3 has a rectangular frame-shaped support surface for supporting the peripheral edge of the thermosetting resin 3a, and is disposed around the lower die D2 so as to be movable in the vertical direction. In the conveying step S3, the thermosetting resin 3a is disposed on the support surface of the lifter D3, for example. The structure of the lifter D3 is an example, and any lifter structure can be used.

In the transfer step S3, the temperature of the upper mold D1 and the lower mold D2 of the mold D for transferring the thermosetting resin 3a is raised to, for example, about 180 ℃. Thereby, the temperature of the lifter D3 is raised to, for example, about 150 ℃. In the transfer step S3, the support surface of the lifter D3 that supports the thermosetting resin 3a is arranged above the cavity-forming surface of the lower mold D2. In the conveying step S3, the height H from the cavity-forming surface of the lower die D2 to the support surface of the lifter D3 on which the thermosetting resin 3a is disposed is, for example, about 5mm to about 10 mm.

The forming step S4 includes, for example, a forming/curing step and a blanking step. As described above, the molding/curing step is a step of curing the thermosetting resin 3a in which the wires 33 are embedded in the mold D to mold the separator 3. Specifically, as shown in fig. 6, after the end of the conveyance step S3, the thermosetting resin 3a is arranged on the support surface of the lifter D3 and supported above the surface of the lower die D2 on which the cavity is formed.

In this state, the lower mold D2 and the upper mold D1 are brought close to each other and clamped, whereby the thermosetting resin 3a is stored in the cavity between the lower mold D2 and the upper mold D1. At this time, the support surface of the lifter D3 is lowered to the level of the cavity-forming surface of the lower die D2. Then, the lower mold D2 and the upper mold D1 are mold-locked to mold the thermosetting resin 3a, and the thermosetting resin 3a is heated and cured by the heat of the upper mold D1 and the lower mold D2. Thereby, the molding/curing process is completed.

The punching step is a step of opening the upper die D1 and the lower die D2 after the molding/curing step, and cutting a part of the thermosetting resin 3a taken out of the lower die D2 by raising the lifter D3 with a die and a punch to mold the separator 3. Specifically, in the punching step, the peripheral edge portion of the cured thermosetting resin 3a is cut to form the sealing portion 32, and the manifold holes 21a, 21b, 22a, 22b, 23a, and 23b are opened in the sealing portion 32. This completes the punching step and the forming step S4, whereby the separator 3 shown in fig. 1 and 2 can be formed.

The operation of the method M for manufacturing a fuel cell separator according to the present embodiment will be described below.

As described above, the method M for manufacturing a fuel cell separator according to the present embodiment is a method for molding a separator 3 having a flow path portion 31 for partitioning fluid flow paths 21, 22, and 23, and a seal portion 32 for sealing the fluid at the peripheral edge portion of the flow path portion 31. The method M for manufacturing a separator for a fuel cell includes: an embedding step S1 of embedding the wire 33 in the uncured thermosetting resin 3a containing the conductive particles 34; and a molding step S4 of curing the thermosetting resin 3a in which the wires 33 are embedded in the mold D to mold the separator 3.

Thus, even if the thermosetting resin 3a disposed on the lifter D3 is softened by heat conduction from the lifter D3 or radiation heat of the lower mold D2 before the upper mold D1 and the lower mold D2 are clamped, the wire rod 33 embedded in the thermosetting resin 3a functions as a core material. Therefore, the shape of the thermosetting resin 3a is maintained by the wire rod 33, and sagging of the thermosetting resin 3a before mold clamping or contact between the thermosetting resin 3a before mold clamping and the lower mold D2 can be prevented. Therefore, the thermosetting resin 3a can be accurately arranged at a predetermined position with respect to the lower mold D2, and the separator 3 can be obtained which is mainly composed of the thermosetting resin 3a lighter than metal while suppressing defects such as wrinkles, cracks, and a local reduction in thickness.

As described above, in the embedding step S1, the wire 33 is used as a core material embedded in the thermosetting resin 3 a. Thus, in the molding step S4, when the thermosetting resin 3a is molded and cured by clamping the upper mold D1 and the lower mold D2, the range in which the thermosetting resin 3a can flow is expanded as compared with a case where a sheet material such as a metal foil is used as a core material, for example. Therefore, the separator 3 mainly composed of the thermosetting resin 3a lighter than metal can be obtained while suppressing the occurrence of defects such as wrinkles, cracks, and a local reduction in thickness in the separator 3.

In the method M for manufacturing a fuel cell separator according to the present embodiment, the wire members 33 woven into a mesh shape are embedded in the thermosetting resin 3a in the embedding step S1.

This can improve the rigidity of the wire 33 serving as the core material of the thermosetting resin 3 a. Therefore, for example, as compared with the case where the wires 33 are arranged in parallel only in one direction, the effect of maintaining the shape of the uncured sheet-like thermosetting resin 3a disposed in the mold D can be improved. Therefore, even if the thermosetting resin 3a is softened by the heat of the mold D when the thermosetting resin 3a is disposed on the lifter D3, the sagging of the thermosetting resin 3a can be more effectively prevented, and the thermosetting resin 3a can be more reliably prevented from coming into contact with the lower mold D2.

When the thermosetting resin 3a is molded in a convex shape, the net-shaped wire members 33 are plastically deformed so that the net shape becomes thick, and stay at an optimum position in the thermosetting resin 3 a. When the thermosetting resin 3a is molded into a concave shape, the net-shaped wire members 33 are plastically deformed so that the net-shaped wire members become dense, and stay at an optimum position in the thermosetting resin 3 a. As a result, the mesh-like wires 33 are freely deformed, and the mesh-like wires 33 can be prevented from being wrinkled in the mold D unlike the sheet-like core material such as a metal foil. In addition, as the wire 33 expands and contracts in this way, the wire 33 is not exposed on the surface of the thermosetting resin 3a, and the thermosetting resin 3a is cured in a state where the wire 33 is embedded in the thermosetting resin 3 a.

Therefore, the separator 3 mainly composed of the thermosetting resin 3a lighter than metal can be obtained while suppressing the occurrence of defects such as wrinkles, cracks, and a local reduction in thickness in the separator 3. The strength of the separator 3 is ensured by the strength and thickness of the cured thermosetting resin 3 a.

Further, the method M for manufacturing a fuel cell separator according to the present embodiment includes, after the embedding step S1 and before the forming step S4: a precuring step S2 of precuring the thermosetting resin 3 a; and a conveying step S3 of conveying the thermosetting resin 3a, in which the wire rod 33 is embedded and pre-cured, to the mold D.

This makes it possible to perform the embedding step S1 of embedding the wire 33 in the uncured thermosetting resin 3a outside the mold D. In the pre-curing step S2, the uncured thermosetting resin 3a in which the wire rods 33 are embedded is pre-cured, and can be conveyed to the mold D in the conveying step S3. This improves the degree of freedom in the embedding step S1 and the molding step S4, thereby improving the productivity of the separator 3.

In the method M for manufacturing a fuel cell separator according to the present embodiment, the conductive particles 34 contained in the thermosetting resin 3a are carbon particles. In the embedding step S1, as shown in fig. 4 and 5, the volume ratio of the carbon particles contained in the thermosetting resin 31a disposed in the region corresponding to the flow path section 31 of the separator 3 is set to 65% to 75%.

As a result, as shown in fig. 2, the MEGA2 can set the contact resistance between the anode-side and cathode-side separators 3, 3 that are in contact with the MEGA2 to an appropriate value for the cell 1. In the two adjacent cells 1, the contact resistance between the anode-side separator 3 of one cell 1 and the cathode-side separator 3 of the other cell 1 can be set to a value appropriate for the group 10.

When the volume ratio of the carbon particles contained in the thermosetting resin 31a is 75% or less, the strength of the flow path section 31 of the separator 3 after molding can be ensured, and the carbon particles can be prevented from falling off. On the other hand, if the volume ratio of the carbon particles contained in the thermosetting resin 31a exceeds 75%, the strength of the flow path section 31 of the separator 3 after molding may be reduced, and the carbon particles may fall off.

In the method M for manufacturing a fuel cell separator according to the present embodiment, in the embedding step S1, as shown in fig. 4 and 5, the volume ratio of carbon particles contained in the thermosetting resin 32a disposed in the region corresponding to the sealing portion 32 of the separator 3 is 20% or less.

Thus, the necessity of reducing the contact resistance with the MEGA2 is low in each cell 1, and the content of carbon particles in the thermosetting resin 32a can be sufficiently reduced in the sealing portion 32 of the separator 3 that is not in contact with the separator 3 of the adjacent cell 1. This reduces the amount of carbon particles contained in the thermosetting resin 3a constituting the separator 3, thereby reducing the production cost of the separator 3.

While the embodiments of the method for manufacturing a fuel cell separator according to the present disclosure have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments, and the present disclosure includes such modifications as design changes without departing from the scope of the present disclosure.