JP2005222819A - Manufacturing method of fuel cell separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a separator for a fuel cell, which can prevent insufficient material filling at a corner of a convex portion of the separator, ensure sufficient processing accuracy, and has good moldability.
SOLUTION: A fuel cell including a concave portion forming a flow channel and a convex portion defining the concave portion by press-molding a powdery molding material 60 in which graphite and a thermosetting resin are mixed with a molding die. In the method of manufacturing the separator 30 for use, when the molding material is filled in the mold in which the protruding strip portion 93 for forming the concave portion and the concave strip portion 94 for forming the convex portion are formed, it is opposed to the concave strip portion. The molding material is biased and supplied using the slit plate 120 so that the filling amount of the molding material in the part to be performed is larger than the filling amount of the molding material in the part facing the ridge.
[Selection] Figure 5

Description

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

  A single cell of a fuel cell has a separator for separating fuel gas from air and the like. The separator is formed by pressing and compressing a mixed powder of graphite and a thermosetting resin (for example, see Patent Document 1).

  The separator needs to form a flow channel for allowing fuel gas, air, or the like to flow therethrough. For this reason, the separator includes a concave portion forming a flow channel and a convex portion that partitions the concave portion.

However, the channel groove has a fine and complicated shape. For this reason, conventionally, there is a risk of insufficient material filling at the corners of the convex portions of the separator, it is difficult to ensure sufficient processing accuracy, and there is a problem in moldability.
Japanese Patent Laid-Open No. 8-180892

  The present invention has been made to solve the problems associated with the above-described conventional technology, and can prevent the material from being insufficiently filled at the corners of the convex portions of the separator, ensuring sufficient processing accuracy and good An object of the present invention is to provide a method for producing a separator for a fuel cell having excellent moldability.

In order to achieve the above object, the present invention relates to a concave part forming a flow channel and a convex part that divides the concave part by press molding a powdery molding material mixed with graphite and a thermosetting resin with a molding die. A method of manufacturing a separator for a fuel cell comprising:
When filling the molding material in which the convex part for forming the concave part and the concave part for forming the convex part are formed with the molding material, the molding material is filled in the part facing the concave part. The fuel cell separator manufacturing method is characterized in that the molding material is biased and supplied so that the amount thereof is larger than the filling amount of the molding material in the portion facing the protruding portion.

  According to the present invention, the molding material is satisfactorily filled up to the corner of the concave portion of the molding die for forming the convex portion of the separator, and insufficient filling of the material at the corner of the convex portion of the separator is caused. It is possible to prevent and ensure sufficient processing accuracy. That is, the manufacturing method of the separator for fuel cells which has favorable moldability can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1A is a cross-sectional view showing a single cell 10 of the fuel cell, and FIG. 1B is a plan view showing a fuel cell separator 30.

  A fuel cell is used in the form of a fuel cell stack in which a large number of single cells 10 are stacked, for example, as a driving source for an automobile.

  The single cell 10 is a battery that can obtain electricity in the process of obtaining water by reacting hydrogen and oxygen by utilizing the reverse principle of electrolysis of water. The illustrated single cell 10 is used for a polymer electrolyte fuel cell. This single cell 10 includes a solid polymer film 21, a pair of electrodes 22 and 23 formed on both sides of the solid polymer film 21 in which a catalyst layer is formed, and a separator 30 disposed on both sides of the electrodes 22 and 23. Have.

  The separator 30 includes concave portions 41 and 43 that form flow channel grooves 31, 32, 33, and 34 and convex portions 42 and 44 that partition the concave portions 41 and 43. More specifically, the outer surface 30a of the separator 30 on the electrode 22 side is formed with a concave portion 41 that forms a flow channel 31 for circulating cooling water and a convex portion 42 that partitions the concave portion 41, and is formed on the inner surface 30b. Are formed with a recess 43 that forms a flow channel 32 for circulating fuel gas (hydrogen) and a protrusion 44 that defines the recess 43. The outer surface 30a of the separator 30 on the electrode 23 side is formed with a concave portion 41 forming a flow channel 33 for circulating cooling water and a convex portion 42 defining the concave portion 41, and an inner surface 30b is provided with an oxidizing agent. A concave portion 43 that forms a flow channel 34 for circulating gas (air) and a convex portion 44 that partitions the concave portion 43 are formed.

  The shape and arrangement of the channel grooves 31 to 34 need to consider gas diffusibility, pressure loss, discharge of generated water, cooling performance, etc., and as shown in FIG. It has a configuration.

  FIG. 2A is a schematic cross-sectional view showing an embodiment of a separator molding machine 50 that embodies a method for manufacturing a fuel cell separator 30 according to the present invention, and FIG. 5 is a cross-sectional view showing a slit plate 120 used when filling 60. FIG. In addition, what pressure-molded the molding material 60 is called the "separator-shaped molded object 61" (refer FIG.6 (B)). The molded body 61 is thermally cured to obtain a separator 30 as a part (see FIG. 6C).

  The separator molding machine 50 includes a molding die 70 for press-molding a powdered molding material 60 in which graphite and a thermosetting resin are mixed, a heating unit 100, and a cooling unit 110. The thermosetting resin is, for example, a phenol resin or an epoxy resin. In addition, it is preferable that the resin contained in the molding material 60 has a small diameter, thereby increasing the reaction rate and reducing the space between the graphite, thereby improving the strength of the separator 30 obtained. It is.

  The mold 70 has an upper mold 80 and a lower mold 90 that are relatively close to and away from each other. The upper die 80 has an upper die 81 and an upper punch 82 that can move up and down with respect to the upper die 81. The lower die 90 includes a lower die 91 and a lower punch 92 that can move up and down with respect to the lower die 91. The upper punch 82 and the lower punch 92 have an inner surface shape that matches the outer shape of the separator 30. That is, the upper punch 82 and the lower punch 92 are provided with convex strips 83 and 93 for forming the concave portions 41 forming the flow channel grooves 31 to 34 of the separator 30 and concave portions for forming the convex portions 42 of the separator 30. Strips 84 and 94 are formed. The molding material 60 filled in the cavity 71 is pressure-molded by the upper punch 82 and the lower punch 92 to form a separator-shaped molded body 61. Although not shown, the molding die 70 includes a clamping mechanism for clamping the upper and lower dies 81 and 91, a pressing mechanism for pressing the molding material 60 with the upper and lower punches 82 and 92, and a separator after molding. A known mechanism or member such as an extraction rod for pushing up 30 from the lower mold 90 and taking it out is provided.

  The heating means 100 is used to heat the molding die 70 to increase the temperature of the molded body 61 and to thermoset the resin contained in the molded body 61. The heating means 100 is also used to heat at least a part of the thermosetting resin by heating the molding material 60 at a temperature lower than the temperature at which the thermosetting resin is cured, that is, the temperature at which the crosslinking reaction starts. . The heating means 100 is disposed inside the upper mold 80 and the lower mold 90 and has a heat medium passage through which a heat medium is introduced. The heat medium is not particularly limited, but high-temperature oil is preferable in consideration of cost and handleability. Since the heat medium has a large heat capacity and good heating performance, it is possible to rapidly heat the molded body 61 to the thermosetting temperature of the resin contained in the molded body 61. Further, by controlling the temperature and supply amount of the heat medium, the molding material 60 can be heated at a temperature lower than the temperature at which the thermosetting resin is cured, and at least a part of the thermosetting resin can be melted.

  The cooling means 110 is used for lowering and taking out the temperature of the molded separator 30 by cooling the mold 70 after completion of thermosetting. The cooling means 110 is disposed inside the upper mold 80 and the lower mold 90 and has a refrigerant passage into which a refrigerant is introduced. The refrigerant is not particularly limited, but low temperature water is preferable in consideration of cost and handleability.

  The slit plate 120 is formed with a slit 121 that allows the molding material 60 to pass therethrough and a shielding portion 122 that prevents the molding material 60 from passing therethrough. When the molding plate 70 is filled with the molding material 60, the slit plate 120 has a filling amount of the molding material 60 in the portion facing the concave strip portions 84 and 94 of the molding material 60 in the portion facing the convex strip portions 83 and 93. It is used for supplying the molding material 60 so as to be larger than the filling amount. The slit 121 is formed in a pattern that matches the pattern of the concave portions 84 and 94 of the mold 70, that is, the pattern of the convex portions 42 and 44 of the separator 30. The thickness t of the slit plate 120 is set to be equal to or greater than the length obtained by adding the compression allowance of the molding material 60 to the depth d of the recesses 84 and 94. This is because the molding material 60 supplied in an uneven manner is suitably compressed to obtain a molded body 61 having a good shape.

  Next, a method for manufacturing the fuel cell separator 30 will be described.

  FIGS. 3A to 3C are cross-sectional views for explaining a procedure for supplying the molding material 60 in a previous stage in which the molding material 60 is supplied in an uneven manner, FIGS. 4A, 4B, and 5A. FIGS. 6A to 6C are cross-sectional views for explaining a procedure for supplying the molding material 60 in an uneven manner using the slit plate 120, and FIGS. It is sectional drawing with which it uses for description at the time of completion of pressure molding and thermosetting. In these drawings, the heating means 100 and the cooling means 110 are not shown.

  For example, the nozzle 130 connected to a container (not shown) holding a powdery molding material 60 in which graphite and a thermosetting resin are mixed is moved from a standby position, and the cavity 71 of the lower mold 90 is moved. Place above. Then, as shown in FIG. 3A, the nozzle 130 is moved while discharging the molding material 60, and the molding material 60 is supplied to the cavities 71 of the lower mold 90 almost evenly. When the supply of the molding material 60 is continued and the amount required to fill the cavity 71 of the lower mold 90 is reached, the discharge of the molding material 60 from the nozzle 130 is temporarily stopped.

  Although it is conceivable to subsequently supply the molding material 60 in an uneven manner, the surface of the molding material 60 already supplied in the molding die 70 is scraped and flattened before the molding material 60 is supplied in an uneven manner. It is preferable. Defines the filling amount of the molding material 60 in the part facing the concave strips 84 and 94 and the filling amount of the molding material 60 in the part facing the convex strips 83 and 93 after the molding material 60 is supplied in an uneven manner. This is because the set amount is set accurately.

  Therefore, as shown in FIGS. 3B and 3C, the scraping plate 131 is moved along the upper surface of the lower mold 90, and the surface of the molding material 60 is scraped and flattened. Since the molding material 60 is not heated, the molding material 60 removed from the lower mold 90 can be used again. For this reason, the yield of material improves.

  In the present embodiment, the molding material 60 is biased and supplied using the slit plate 120. Therefore, as shown in FIG. 4A, the slit plate 120 is placed on the upper surface of the lower mold 90. Thereafter, as shown in FIG. 4B, the discharge of the molding material 60 from the nozzle 130 is resumed, and the nozzle 130 is moved. When the amount required to fill the slit 121 is reached, the discharge of the molding material 60 from the nozzle 130 is terminated. The nozzle 130 is retracted to a standby position where it does not interfere with the mold 70.

  It is conceivable to remove the slit plate 120 subsequently, but before removing the slit plate 120, it is preferable to scrape and flatten the surface of the molding material 60 already supplied into the slit 121. In the same manner as described above, the filling amount of the molding material 60 in the portion facing the concave stripe portions 84 and 94 and the molding in the portion facing the convex stripe portions 83 and 93 after the molding material 60 is supplied biased. This is to accurately set the filling amount of the material 60 to a prescribed amount.

  Therefore, as shown in FIGS. 5A and 5B, the scraping plate 131 is moved along the upper surface of the slit plate 120, and the surface of the molding material 60 already supplied into the slit 121 is scraped flat. To. Since the molding material 60 is not heated, the molding material 60 removed from the slit plate 120 can be used again. For this reason, the yield of material improves.

  Further, before removing the slit plate 120, the molding material 60 is heated at a temperature lower than the temperature at which the thermosetting resin is cured to melt at least a part of the thermosetting resin, and the molding material 60 is supplied unevenly. It is preferable to maintain a different shape. When the slit plate 120 is removed, the shape supplied with the molding material 60 is prevented from collapsing, and as a result, the molding material in a portion facing the concave portions 84 and 94 after the slit plate 120 is removed. This is because the filling amount of 60 and the filling amount of the molding material 60 at the portions facing the ridges 83 and 93 are accurately maintained at the prescribed amounts.

  Therefore, after the surface of the molding material 60 already supplied in the slit 121 is scraped and flattened (see FIG. 5B), the heating means 100 is operated to control the temperature and supply amount of the heat medium. Thus, at least a part of the thermosetting resin is melted by heating the molding material 60 at a temperature lower than the temperature at which the thermosetting resin is cured. When the resin is melted, both the molding material 60 filled in the cavity 71 of the lower mold 90 and the molding material 60 filled in the slit 121 are integrated with a viscosity with a force that does not collapse the shape. . Therefore, as shown in FIG. 5C, the slit plate 120 can be removed while maintaining the shape in which the molding material 60 is supplied in an uneven manner.

  There is a concern that the boundary surface between the molding material 60 supplied to the lower mold 90 and the molding material 60 supplied into the slit 121 may become weak. However, there is no difference in material temperature as in the casting water boundary or resin injection molding interface, and because of the integration with the thermosetting resin in the material by heating after pressure molding, the strength problem is Does not occur. Further, even if at least a part of the thermosetting resin is melted in order to maintain the shape in which the molding material 60 is supplied in an uneven manner, the original thermosetting is caused by heating after the pressure molding. The problem does not arise as well.

  Next, as shown in FIG. 6A, the upper die 80 is lowered and brought close to the lower die 90, and the upper and lower dies 81 and 91 are clamped. Thereafter, as shown in FIG. 6B, the molding material 60 is pressure-molded by the upper and lower punches 82 and 92 in the non-heated state. At this time, since the molding material 60 is not thermally cured, the corners of the lower mold 90 and the upper mold 80 are satisfactorily filled.

  Thereafter, a heat medium is introduced into the heat medium passage and the mold 70 is heated, whereby the temperature of the molded body 61 is raised and the resin contained in the molded body 61 is thermally cured. When the heating rate of the molded body 61 is low, the resin in the middle of curing moves to the surface and corners and concentrates locally, thereby forming a resin-rich portion, resulting in poor graphite dispersion. In the present embodiment, since the molded body 61 is rapidly heated by the heat medium, it is possible to prevent the formation of a resin-rich portion and suppress poor graphite dispersion. Furthermore, rapid heating shortens the thermosetting time, and the cycle time can be shortened.

  When the thermosetting is completed and the separator 30 is formed as shown in FIG. 6C, the introduction of the heat medium into the heat medium passage is stopped, while the refrigerant is introduced into the refrigerant passage and the mold 70 is cooled. To do. When the temperature of the separator 30 falls to, for example, room temperature, the upper and lower molds 80 and 90 are opened, and the separator 30 is taken out. Since the separator 30 is rapidly cooled by the refrigerant through the mold 70, the cooling time is shortened, and the cycle time can be further shortened.

  7 (A) and 7 (B) are diagrams conceptually showing the behavior of the material flow in the concave strips 84 and 94 when the molding material 60 is pressure-molded, and FIG. The case of this manufacturing method is shown, and FIG. 5B shows the case of a comparative manufacturing method. In contrast, the surface of the filled molding material 60 is formed flat. Although a part of the upper punch 82 is shown, the same flow behavior occurs in the lower punch 92.

  In the case of proportionality, the molding material 60 is pushed out by the convex strips 83, 93 of the upper and lower punches 82, 92 as shown by arrows in FIG. Exhibits a flowing behavior. Since the degree of transfer (distance, amount, etc.) of the molding material 60 is large, a situation where the material is not sufficiently filled in the corner portions of the concave portions 84 and 94 is likely to occur, and the material defect portion 62 is generated. Therefore, the separator-shaped molded body 61 cannot ensure sufficient processing accuracy. Therefore, in the separator 30 after molding, the convex portions 42 and 44 become weak or gas or the like permeates, and the characteristics of the fuel cell become insufficient.

  On the other hand, in the present embodiment, as indicated by an arrow in FIG. 7A, the molding material 60 behaves as if it is pushed out of the concave stripe portions 84 and 94 and flows. For this reason, the material is sufficiently and satisfactorily filled up to the corners of the concave portions 84 and 94, and the material defect portion 62 as in the proportional proportion does not occur. Therefore, the separator-shaped molded body 61 has good processing accuracy. Therefore, in the separator 30 after molding, the convex portions 42 and 44 do not become weak, and gas or the like does not permeate, and a fuel cell having sufficient characteristics can be obtained.

  As described above, according to the present embodiment, the ridges 83 and 93 for forming the recesses 41 and 43 of the separator 30 and the ridges 84 and 94 for forming the projections 42 and 44 are formed. When the molding material 60 is filled with the molding material 60, the filling amount of the molding material 60 at the portion facing the recesses 84 and 94 is larger than the filling amount of the molding material 60 at the portion facing the protrusions 83 and 93. Since the molding material 60 is supplied biased so as to increase, the molding material 60 is good up to the corners of the concave strips 84 and 94 of the molding die 70 for forming the convex portions 42 and 44 of the separator 30. It is possible to prevent the material from being insufficiently filled at the corners of the convex portions 42 and 44 of the separator 30 and to ensure sufficient processing accuracy. That is, the manufacturing method of the separator 30 for fuel cells which has favorable moldability can be provided.

  In addition, since the surface of the molding material 60 already supplied in the mold 70 is flattened before the molding material 60 is supplied in an uneven manner, the concave stripe after the molding material 60 is supplied in an uneven manner. The amount of filling of the molding material 60 at the part facing the parts 84, 94 and the amount of filling of the molding material 60 at the part facing the protruding strips 83, 93 can be accurately set to the prescribed amount, and sufficient processing accuracy Can be provided. In addition, the material yield can be improved.

  In addition, since the slit plate 120 is used, the operation of supplying the molding material 60 in an uneven manner can be performed easily and quickly.

  In addition, since the slit 121 is formed in a pattern that matches the pattern of the concave stripe portions 84 and 94, the convex portions 42 and 44 for defining the concave portions 41 and 43 forming the flow channel grooves 31 to 34 can be easily and easily formed. It can be formed with sufficient processing accuracy.

  Moreover, since the thickness of the slit plate 120 is set to be equal to or longer than the depth of the concave strip portions 84 and 94 plus the compression allowance of the molding material 60, the concave portion 41 forming the channel grooves 31 to 34 is formed. , 43 can be formed with simple and sufficient processing accuracy.

  Further, before removing the slit plate 120, the surface of the molding material 60 already supplied into the slit 121 is rubbed and flattened, so that the concave portions 84 and 94 after the molding material 60 is supplied in an uneven manner. The amount of filling of the molding material 60 in the portion facing the surface and the amount of filling of the molding material 60 in the portion facing the ridges 83 and 93 can be accurately set to a prescribed amount, and fuel with sufficient processing accuracy A battery separator 30 can be provided. In addition, the material yield can be improved.

  Further, before removing the slit plate 120, the molding material 60 is heated at a temperature lower than the temperature at which the thermosetting resin is cured to melt at least a part of the thermosetting resin, and the molding material 60 is supplied unevenly. Since the shape is maintained, after the slit plate 120 is removed, the filling amount of the molding material 60 in the portion facing the concave strip portions 84 and 94 and the portion facing the convex strip portions 83 and 93 are obtained. The fuel cell separator 30 can be provided in which the filling amount of the molding material 60 can be accurately maintained at a specified amount and sufficient processing accuracy is ensured. In addition, the material yield can be improved.

  In order to maintain the shape in which the molding material 60 is supplied in an uneven manner, a heating means is disposed on the slit plate 120, and the molding material 60 is heated at a temperature lower than the temperature at which the thermosetting resin cures to be thermoset. At least a part of the functional resin may be melted.

  Moreover, although embodiment which supplies the molding material 60 biased using the slit board 120 was demonstrated, this invention is not limited to this case. By supplying the molding material 60 from the nozzle 130, the molding material 60 can be supplied evenly.

  Moreover, the heating means 100 is not limited to a form using a heat medium, and electromagnetic induction heating, ultrasonic heating, resistance heating (resistance heating element), or the like can be applied as appropriate. Electromagnetic induction heating and ultrasonic heating are preferable from the viewpoint of rapid heating, as in the case of a heating medium. Furthermore, electromagnetic induction heating is also preferable in that it has a function of directly heating carbon contained in the molded body 61.

  FIG. 8 is a schematic cross-sectional view showing another embodiment of a separator molding machine 50 that embodies the method for manufacturing a fuel cell separator 30 according to the present invention. Note that members that are the same as those shown in FIG. 2 are given the same reference numerals, and descriptions thereof are partially omitted. Further, the heating means 100 and the cooling means 110 are not shown.

  A mold 70 of a separator molding machine 50 according to another embodiment has an upper mold 80 and a lower mold 90 that are relatively close to and away from each other, like the separator molding machine 50 shown in FIG. A plurality of split dies 85 are provided on the upper punch 82 of the upper die 80. The split mold 85 constitutes a concave strip portion 84 for forming the convex portions 42 and 44 of the separator 30.

  At the time of pressure molding of the molding material 60, the molding material 60 that is supplied in an uneven manner and is located in the concave portion 84 is pressed by each split mold 85. The pressing force by the split mold 85 is preferably set to be higher than the pressing force by the ridge 83 of the upper punch 82. If it does in this way, the behavior (refer FIG. 7 (A)) in which the molding material 60 in the recessed stripe parts 84 and 94 will be extruded from the said recessed stripe parts 84 and 94 will flow reliably will arise, and the recessed stripe part 84 will be produced. , 94 can be more fully and satisfactorily filled into the corners. Therefore, the separator-shaped molded body 61 has better processing accuracy.

  It should be noted that the lower punch 92 of the lower mold 90 can also be provided with a split mold that constitutes the recess 94.

  The present invention can be applied to an application for manufacturing a fuel cell separator.

1A is a cross-sectional view showing a single cell of a fuel cell, and FIG. 1B is a plan view showing a fuel cell separator. FIG. 2A is a schematic cross-sectional view showing an embodiment of a separator molding machine that embodies a method for manufacturing a fuel cell separator according to the present invention, and FIG. 2B is a diagram in which a molding material is filled in the separator molding machine. It is sectional drawing which shows the slit board used in the case. FIGS. 3A to 3C are cross-sectional views for explaining the procedure of supplying the molding material in the previous stage of supplying the molding material in an uneven manner. 4 (A) and 4 (B) are cross-sectional views for explaining a procedure for supplying a molding material in an uneven manner using a slit plate. FIGS. 5A to 5C are cross-sectional views for explaining a procedure for supplying the molding material in an uneven manner using a slit plate. 6 (A) to 6 (C) are cross-sectional views for explaining the completion of mold clamping, molding material pressure molding, and thermosetting. 7 (A) and 7 (B) are diagrams conceptually showing the behavior of the material flow in the recess when the molding material is pressure-molded, and FIG. 7 (A) is based on the manufacturing method of the embodiment. FIG. 5B shows the case of a comparative manufacturing method. It is a schematic sectional drawing which shows other embodiment of the separator molding machine which embodies the manufacturing method of the separator for fuel cells which concerns on this invention.

Explanation of symbols

10 single cell,
21 solid polymer membrane,
22, 23 electrodes,
30 Separator for fuel cell,
31-34 channel grooves,
41, 43 Recesses forming flow channel grooves,
42, 44 convex part,
50 separator molding machine,
60 molding materials,
61 Separator-shaped molded body,
70 mold,
80 upper mold,
81 top die,
82 top punch,
83 ridges,
84 Recessed section,
85 split type,
90 Lower mold,
91 Lower die,
92 Lower punch,
93 ridges,
94 Concave part,
100 heating means,
110 cooling means,
120 slit plate,
121 slits,
122 shielding part,
130 nozzles,
131 Frayed board.

Claims (7)

A fuel cell separator having a concave portion forming a flow channel and a convex portion defining the concave portion is manufactured by pressure molding a powdery molding material obtained by mixing graphite and a thermosetting resin with a molding die. In the method
When filling the molding material in which the convex part for forming the concave part and the concave part for forming the convex part are formed with the molding material, the molding material is filled in the part facing the concave part. A method for producing a fuel cell separator, characterized in that the molding material is biased and supplied so that the amount thereof is larger than the filling amount of the molding material in a portion facing the ridge.   2. The method for producing a fuel cell separator according to claim 1, wherein the surface of the molding material already supplied in the molding die is scraped and flattened before the molding material is supplied in an uneven manner.   2. The fuel cell separator according to claim 1, wherein the molding material is biased and supplied using a slit plate in which a slit that allows passage of the molding material and a shielding portion that prevents passage of the molding material is formed. 3. Manufacturing method.   4. The method for manufacturing a fuel cell separator according to claim 3, wherein the slit is formed in a pattern that matches the pattern of the recess.   4. The fuel cell separator according to claim 3, wherein the thickness of the slit plate is set to be equal to or greater than the depth of the concave portion plus the compression allowance of the molding material. 5. Method.   4. The method for producing a fuel cell separator according to claim 3, wherein the surface of the molding material already supplied in the slit is scraped and flattened before removing the slit plate.   Before removing the slit plate, the molding material is heated at a temperature lower than the temperature at which the thermosetting resin cures to melt at least a part of the thermosetting resin, and the molding material is held in an unevenly supplied shape. The method for producing a fuel cell separator according to claim 3, wherein:

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