Manufacturing method of fuel cell separator

Abstract

To provide a method for manufacturing a fuel cell separator, capable of achieving an improvement in productivity and an improvement in formability of a material sheet.SOLUTION: Provided is a method for manufacturing a fuel cell separator, in which a material sheet 11 including conductive fillers dispersed in a thermoplastic resin material is subjected to heat press molding using a heat press device, to manufacture a fuel cell separator. The method includes an adjustment process of adjusting the fluidity of the material sheet 11 before the material sheet 11 is subjected to heat press.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a separator for a fuel cell. [Background technology]

[0002] Patent Document 1 discloses a method for manufacturing a separator for a fuel cell, which includes a laminate forming step and a conductive layer forming step. In the laminate formation process, a first plate material and a pair of second plate materials are laminated in the order of second plate material, first plate material, and second plate material to form a laminate (hereinafter referred to as a material sheet). The first plate material is formed from a first mixture in which a conductive first carbon material is dispersed in a resin material. The second plate material is formed from a second mixture in which a conductive second carbon material is dispersed in a resin material. The resin material is, for example, a thermoplastic resin such as polypropylene resin. The first carbon material and the second carbon material are, for example, natural graphite such as spherical graphite.

[0003] In the conductive layer forming process, a material sheet is heated and pressurized using a press device to form a plurality of protrusions on the surface of the laminate, and a plurality of gas flow path sections located between adjacent protrusions and through which reactive gas flows. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-180150 Summary of the Invention [Problem to be solved by the invention]

[0005] When a separator is manufactured by heating and pressurizing a material sheet using the press device described in Patent Document 1, if the temperature of the press device is set high to increase the fluidity of the material sheet, the following problem occurs: After molding the material sheet, it takes a long time to cool the press device down to a temperature at which the material sheet can be removed from the press device, making it difficult to improve productivity.

[0006] To address this issue, it is conceivable to set the temperature of the press machine relatively low and preheat the blank sheet with a heater before transferring it to the press machine to increase the fluidity of the blank sheet. However, in this case, heat is transferred from the heated blank sheet to the relatively cool press machine, and the blank sheet's fluidity decreases as its temperature drops before the hot pressing is completed. As a result, the blank sheet's formability deteriorates. [Means for solving the problem]

[0007] A method for manufacturing a fuel cell separator to solve the above problem is a method for manufacturing a fuel cell separator by hot-pressing a material sheet having a conductive filler dispersed in a thermoplastic resin material using a hot-press device, and includes an adjustment step for adjusting the fluidity of the material sheet before hot-pressing the material sheet.

[0008] According to this method, the material sheet is heat-pressed in a state where the fluidity of the material sheet is adjusted. Therefore, it is possible to increase the fluidity of the material sheet while setting the temperature of the heat press device low. Therefore, it is possible to improve productivity and the formability of the material sheet.

[0009] In the above-mentioned method for manufacturing a fuel cell separator, the material sheet is formed from a paint formed by mixing the resin material, the filler, and a solvent, and in the adjustment process, it is preferable that the mass percentage concentration of the solvent in the material sheet is set to 2 wt% or more and 8 wt% or less.

[0010] According to this method, the mass percent concentration of the solvent in the material sheet is 2 wt% or more, so the material sheet can be heat-pressed while maintaining its fluidity. Also, the mass percent concentration of the solvent in the material sheet is 8 wt% or less, so cracks in the material sheet caused by excessive solvent vaporization during heat-pressing can be suppressed.

[0011] In the above-mentioned method for manufacturing a fuel cell separator, the mass percentage concentration of the solvent in the paint is 30 wt% or more and 40 wt% or less, and the material sheet is formed by extruding the paint into a strip or sheet shape using an extrusion device and then heating and drying it using a drying device, and in the adjustment process, it is preferable that the mass percentage concentration of the solvent in the material sheet be 2 wt% or more and 8 wt% or less by volatilizing part of the solvent using the drying device.

[0012] According to this method, the mass percent concentration of the solvent in the paint when extruded by the extrusion device is 30 wt% or more, so the fluidity of the paint required for smooth extrusion by the extrusion device can be obtained. Also, the mass percent concentration of the solvent in the paint when extruded by the extrusion device is 40 wt% or less, so the fluidity of the paint does not become excessively high. Therefore, the shape retention of the material sheet can be improved.

[0013] In the above-mentioned method for manufacturing a fuel cell separator, it is preferable that the material sheet has a first portion that faces the power generation section of the fuel cell and a second portion that surrounds the first portion, and that in the adjustment process, the material sheet is heated so that the degree of heating of the first portion is smaller than that of the second portion, thereby making the proportion of the solvent contained in the first portion greater than the proportion of the solvent contained in the second portion, thereby making the fluidity of the first portion greater than that of the second portion.

[0014] A groove-shaped gas flow path through which reactant gas flows is formed in the portion of the fuel cell separator facing the power generation unit. On the other hand, no gas flow path is formed in the portion of the fuel cell separator surrounding the above portion. For this reason, the first portion of the material sheet facing the power generation unit is required to have higher fluidity than the second portion surrounding the first portion.

[0015] In this regard, by heating the material sheet using the above method, the proportion of solvent contained in the first portion can be made greater than the proportion of solvent contained in the second portion, thereby making the fluidity of the first portion higher than that of the second portion.

[0016] In the above-described method for manufacturing a fuel cell separator, it is preferable that in the adjusting step, the material sheet is heated by irradiating the material sheet with infrared rays while the first portion is masked.

[0017] According to this method, by masking the first portion, it is possible to easily heat the material sheet so that the degree of heating of the first portion is smaller than that of the second portion. In the above-mentioned method for manufacturing a fuel cell separator, it is preferable that the material sheet is porous, and in the adjustment process, the surface of the material sheet facing the fixed mold of the heat press device is covered with a covering sheet formed of a thermoplastic resin having a lower thermal conductivity than the material sheet, and the material sheet and the covering sheet are heated to a temperature higher than the temperature of the heat press device.

[0018] According to this method, the material sheet is covered with a covering sheet and placed on the fixed mold in a state where it is heated to a temperature higher than that of the heat press device. Therefore, the material sheet does not come into contact with the relatively low-temperature fixed mold. Here, the covering sheet is made of a thermoplastic resin with a lower thermal conductivity than the material sheet, so heat transfer from the material sheet to the fixed mold is suppressed. This allows the temperature of the material sheet to be kept high during heat pressing, i.e., the fluidity of the material sheet can be maintained high.

[0019] Furthermore, a portion of the covering sheet softened by the heat pressing penetrates into the voids in the material sheet, which prevents the covering sheet from forming a layer of resin alone on one side of the separator, thereby preventing an increase in the contact resistance of the separator.

[0020] In the above-described method for manufacturing a fuel cell separator, it is preferable that in the adjusting step, the material sheet and the covering sheet are heated to a temperature higher than the temperature of the heat press device while both sides of the material sheet are covered with the covering sheet.

[0021] According to this method, the material sheet does not come into contact with either the fixed or movable mold. This suppresses the transfer of heat from the material sheet to either the fixed or movable mold. This makes it possible to maintain a higher temperature of the material sheet during hot pressing, i.e., to maintain high fluidity of the material sheet.

[0022] Furthermore, by providing the cover sheet, it is possible to prevent a layer of only resin from being formed on both sides of the separator. [Effects of the Invention]

[0023] According to the present invention, it is possible to improve the productivity of fuel cell separators and the formability of material sheets. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a cross-sectional view of a separator according to a first embodiment. [Figure 2] FIG. 2 is an enlarged cross-sectional view of the material sheet according to the first embodiment. [Figure 3] FIG. 3 is a schematic diagram mainly showing the extrusion device and the drying device according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view of the heat press device according to the first embodiment. [Figure 5] FIG. 5 is a cross-sectional view corresponding to FIG. 4 and showing the state in which the molds are clamped. [Figure 6] FIG. 6 is a front view corresponding to FIG. 4 and showing the mold in an open state. [Figure 7] FIG. 7(a) is a perspective view of a material sheet according to the second embodiment, and FIG. 7(b) is a perspective view of a state in which a mask is placed on the material sheet according to the second embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing a material sheet body and a covering sheet according to the third embodiment. [Figure 9] FIG. 9 is a graph showing the change over time in temperature of the material sheet when the material sheet according to the third embodiment is hot-pressed. [Figure 10] FIG. 10 is a graph showing the change over time in temperature of a material sheet when the material sheet according to the comparative example of the third embodiment is hot-pressed. DETAILED DESCRIPTION OF THE INVENTION

[0025] First Embodiment A first embodiment of a method for manufacturing a fuel cell separator will be described below with reference to FIGS.

[0026] First, the general structure of a fuel cell separator (hereinafter, separator 10) will be described. As shown in FIG. 1, the separator 10 is a member that constitutes a cell by sandwiching a power generating section of a fuel cell together with other separators 10 (both not shown).

[0027] A portion 10A of the separator 10 facing the power generation unit is formed with a plurality of groove-shaped gas flow channels 10a through which the reaction gas flows. A plurality of groove-shaped coolant flow channels 10b are formed on the surface of the separator 10 opposite to the surface on which the gas flow channels 10a are formed. The coolant flow channels 10b are formed between adjacent gas flow channels 10a. A portion 10B of the separator 10 surrounding the portion 10A is not formed with the gas flow channels 10a or the coolant flow channels 10b.

[0028] The separator 10 is manufactured by heat-pressing a material sheet 11 in which a conductive filler 14 is dispersed in a thermoplastic resin material 13 using a heat press device 60 . As shown in FIG. 2, the material sheet 11 before being heat-pressed contains a resin material 13, a filler 14, and a solvent 15.

[0029] The resin material 13 is, for example, polyethersulfone (PES). The filler 14 is, for example, a carbon material, more specifically, carbon particles or carbon fibers. The solvent 15 is, for example, N-methyl-2-pyrrolidone (NMP).

[0030] Next, the manufacturing apparatus 100 for the separator 10 will be described. As shown in FIGS. 3 to 6, the manufacturing apparatus 100 includes an extrusion device 20, a conveying device 30, a drying device 40, a cutting device 50, and a heat pressing device 60.

[0031] <Extrusion device 20> 3, the extrusion device 20 is a device that extrudes the paint 12 in a strip shape. The extrusion device 20 includes a cylinder 21, a screw 22, a hopper 23, and a drive device 24.

[0032] The cylinder 21 extends horizontally. In the following description, the direction in which the cylinder 21 extends will simply be referred to as the extension direction L. At the tip of the cylinder 21 in the extension direction L, an extrusion port 21a is provided.

[0033] The screw 22 is rotatably housed within the cylinder 21 . The hopper 23 is disposed above the cylinder 21 and supplies the paint 12 into the cylinder 21 .

[0034] The driving device 24 includes a motor (not shown) that rotates the screw 22. The base end of the screw 22 is connected to an output shaft of the motor. <Conveyor device 30> As shown in FIG. 3, the conveying device 30 is adjacent to the extrusion outlet 21a of the extrusion device 20 in the extension direction L and includes a conveying belt 31 extending in the extension direction L.

[0035] The conveyor belt 31 conveys the paint 12 extruded in a strip shape from the extrusion port 21a toward the opposite side of the extrusion device 20 in the extension direction L. <Drying device 40> As shown in FIG. 3, the drying device 40 is provided midway along the conveying device 30 in the extending direction L.

[0036] The drying device 40 includes a heater 41 that heats and dries the strip-shaped paint 12. The heater 41 is provided on the opposite side of the paint 12 to the conveyor belt 31 (upper side in FIG. 3). <Cutting device 50> As shown in FIG. 3, the cutting device 50 is provided on the opposite side of the drying device 40 to the extrusion device 20 in the extension direction L.

[0037] The cutting device 50 cuts the strip-shaped paint 12 to a predetermined length to form the material sheet 11. The cutting device 50 is equipped with a cutting blade 51 that moves up and down. <Heat press device 60> As shown in FIG. 4, the heat press device 60 includes a fixed mold 61 and a movable mold 65 that is arranged above the fixed mold 61 and is configured to be able to move up and down.

[0038] A lower insert 62 is provided on the upper part of the fixed mold 61. A lower molding surface 63 is formed on the upper surface of the lower insert 62. The lower molding surface 63 has a plurality of recessed grooves 64 that form a plurality of gas flow paths 10a. A heater (not shown) is built into the fixed mold 61.

[0039] An upper insert 66 is provided at the bottom of the movable die 65. An upper molding surface 67 is formed on the bottom surface of the upper insert 66. The upper molding surface 67 has a plurality of ridges 68 that form a plurality of coolant flow paths 10b. A heater (not shown) is built into the movable die 65.

[0040] Next, a procedure for manufacturing the separator 10 using the manufacturing apparatus 100 will be described. As shown by arrow A in FIG. 3, the paint 12 formed by mixing the resin material 13, the filler 14, and the solvent 15 is poured into the hopper .

[0041] Here, the mass percent concentration of the solvent 15 contained in the paint 12 is preferably 30 wt % or more and 40 wt % or less. The paint 12 is supplied into the cylinder 21 through a hopper 23 .

[0042] As shown by arrow B in FIG. 3, the paint 12 supplied into the cylinder 21 is extruded by the screw 22 from the extrusion port 21 a onto the conveyor belt 31 in a strip shape. The paint 12 is conveyed by the conveyor belt 31 and is heated and dried when passing through the drying device 40 .

[0043] Here, the drying device 40 heats and evaporates part of the solvent 15 contained in the paint 12, so that the mass percent concentration of the solvent 15 in the material sheet 11 becomes 2 wt% or more and 8 wt% or less.

[0044] The dried paint 12 is cut as it passes through the cutting device 50, thereby forming the material sheet 11 of a predetermined length. 4, the material sheet 11 is carried into a heat press device 60. More specifically, the material sheet 11 is placed on a lower insert 62.

[0045] Thereafter, the heater is energized to heat the fixed mold 61 and the movable mold 65 to a first predetermined temperature, which is, for example, 400°C. Then, as shown in FIG. 5, the movable die 65 is lowered to the bottom dead center, whereby the material sheet 11 is heat-pressed.

[0046] Thereafter, the heater is de-energized, and the temperatures of the fixed mold 61 and the movable mold 65 begin to decrease. When the temperatures of the fixed mold 61 and the movable mold 65 are cooled to a second predetermined temperature that is lower than the first predetermined temperature, the movable mold 65 is raised to the top dead center to open the mold, and the material sheet 11 is removed from the lower insert 62, as shown in Fig. 6. The second predetermined temperature is, for example, 200°C.

[0047] In the first embodiment, the step of heating and drying the paint 12 corresponds to the adjusting step described in the "Means for solving the problems" section. The operation of this embodiment will be described.

[0048] The mass percent concentration of the solvent 15 contained in the paint 12 is 30 wt% or more and 40 wt% or less. Thereafter, the paint 12 is heated and dried to volatilize the solvent 15 to form the material sheet 11, and the mass percent concentration of the solvent 15 contained in the material sheet 11 is set to 2 wt% or more and 8 wt% or less.

[0049] In this way, by adjusting the mass percent concentration of the solvent 15 in the adjustment step, the material sheet 11 is heat-pressed in a state in which the fluidity of the material sheet 11 is adjusted. The effects of this embodiment will be described.

[0050] (1-1) The method for manufacturing a fuel cell separator includes a conditioning step before the material sheet 11 is heat-pressed. According to this method, the above-mentioned effect is achieved, and it is possible to increase the fluidity of the material sheet 11 while setting the temperature of the heat press device 60 low. Therefore, it is possible to improve the productivity and the formability of the material sheet 11.

[0051] (1-2) The mass percent concentration of the solvent 15 in the material sheet 11 is adjusted to 2 wt % or more and 8 wt % or less by the drying device 40. According to this method, the mass percent concentration of the solvent 15 in the material sheet 11 is 2 wt% or more, so that the material sheet 11 can be heat-pressed while maintaining the fluidity. In addition, the mass percent concentration of the solvent 15 in the material sheet 11 is 8 wt% or less, so that it is possible to prevent cracks from occurring in the material sheet 11 due to excessive solvent 15 vaporizing during heat-pressing.

[0052] (1-3) The mass percent concentration of the solvent 15 in the paint 12 is 30 wt% or more and 40 wt% or less. Then, by volatilizing a portion of the solvent 15 using the drying device 40, the paint 12 is formed on the material sheet 11, and the mass percent concentration of the solvent 15 in the material sheet 11 is set to 2 wt% or more and 8 wt% or less.

[0053] According to this method, the mass percent concentration of the solvent 15 in the coating material 12 when extruded by the extrusion device 20 is 30 wt% or more, so that the fluidity of the coating material 12 required for smoothly extruding the coating material 12 by the extrusion device 20 can be obtained. Furthermore, the mass percent concentration of the solvent 15 in the coating material 12 when extruded by the extrusion device 20 is 40 wt% or less, so that the fluidity of the coating material 12 does not become excessively high. Therefore, the shape retention of the material sheet 11 can be improved.

[0054] Second Embodiment The second embodiment will be described below with reference to Figures 7(a) and 7(b). In the second embodiment, the same or corresponding components as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

[0055] As shown in FIG. 7(a), the material sheet 11 has a first portion 11A that becomes the portion 10A facing the power generation section of the fuel cell, and a second portion 11B that surrounds the first portion 11A. In this embodiment, the material sheet 11 is heated before being carried into the heat press device 60 so that the degree of heating of the first portion 11A is lower than that of the second portion 11B. As a result, the proportion of the solvent 15 contained in the first portion 11A is made higher than the proportion of the solvent 15 contained in the second portion 11B, thereby making the fluidity of the first portion 11A higher than that of the second portion 11B.

[0056] Specifically, as shown in Fig. 7(b), the material sheet 11 is heated by irradiating it with infrared rays while a mask 70 is placed on the first portion 11A. After heating of the material sheet 11 is completed, the mask 70 is removed. The infrared irradiation is performed by an infrared irradiation device (not shown).

[0057] The mass percentage concentration of the solvent 15 in the first portion 11A and the second portion 11B after heating is 2 wt% or more and 8 wt% or less, and the proportion of the solvent 15 contained in the first portion 11A is greater than the proportion of the solvent 15 contained in the second portion 11B.

[0058] In the second embodiment, the step of heating the material sheet 11 corresponds to the adjusting step described in the "Means for solving the problems" section. The operation of this embodiment will be described.

[0059] In the adjusting step, the material sheet 11 is heated so that the first portion 11A is heated to a smaller degree than the second portion 11B, thereby making the proportion of the solvent 15 contained in the first portion 11A greater than the proportion of the solvent 15 contained in the second portion 11B. This makes the fluidity of the first portion 11A higher than the fluidity of the second portion 11B.

[0060] The effects of this embodiment will be described. (2-1) In the heating step, the material sheet 11 is heated so that the degree of heating of the first portion 11A is smaller than that of the second portion 11B, thereby making the proportion of the solvent 15 contained in the first portion 11A greater than the proportion of the solvent 15 contained in the second portion 11B.

[0061] Groove-shaped gas flow paths 10a through which the reactant gas flows are formed in a portion 10A of the separator 10 that faces the power generation unit. On the other hand, no gas flow paths 10a are formed in a portion 10B of the separator 10 that surrounds the portion 10A. For this reason, the first portion 11A of the material sheet 11, which is the portion 10A that faces the power generation unit, is required to have higher fluidity than the second portion 11B that surrounds the first portion 11A.

[0062] In this regard, the method described above has the above-mentioned effect, and therefore the formability of the first portion 11A in which the groove shape is formed can be made higher than the formability of the second portion 11B in which the groove shape is not formed.

[0063] (2-2) In the heating step, the material sheet 11 is heated by irradiating the material sheet 11 with infrared rays while the first portion 11A is masked. According to this method, by masking the first portion 11A, it is possible to easily heat the material sheet 11 so that the degree of heating of the first portion 11A is smaller than that of the second portion 11B.

[0064] <Third embodiment> The third embodiment will be described below with reference to Figures 8 to 10. In the third embodiment, the same or corresponding configurations as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

[0065] As shown in FIG. 8, the material sheet 80 has a material sheet body 81 and a covering sheet 82. The material sheet body 81 is porous and contains a resin material 13 and a filler 14 .

[0066] The pair of covering sheets 82 respectively cover both sides of the material sheet body 81. That is, one covering sheet 82 covers the surface of the material sheet body 81 facing the fixed mold 61 of the heat press device 60. The other covering sheet 82 covers the surface of the material sheet body 81 facing the movable mold 65 of the heat press device 60.

[0067] The covering sheet 82 is made of a thermoplastic resin having a lower thermal conductivity than the material sheet body 81. The resin constituting the covering sheet 82 is, for example, polyethersulfone (PES).

[0068] The thickness of the covering sheet 82 is smaller than the thickness of the material sheet body 81. In this embodiment, before the material sheet 80 is carried into the heat press device 60, the material sheet 80 is heated by a heater (not shown) to a temperature T3 that is higher than the heat press temperature.

[0069] In the third embodiment, the process of covering both sides of the material sheet main body 81 with a pair of covering sheets 82 to form the material sheet 80, and the process of heating the material sheet 80 with a heater correspond to the adjustment process described in the "Means for solving the problem" section.

[0070] The operation of this embodiment will be described. As shown in Figure 9, in order to increase the fluidity of the material sheet 80 and perform heat press molding appropriately, it is necessary to heat press mold the material sheet 80 within a temperature range of not less than a first temperature T1 and not more than a second temperature T2.

[0071] In this embodiment, the material sheet body 81 is covered with the covering sheet 82 and heated by a heater to a temperature T3 that is higher than the heat pressing temperature of the heat pressing device 60. At time t0, the material sheet 80 is removed from the heater and carried into the heat press device 60. During this time, the temperature of the material sheet 80 gradually decreases. Then, at time t1, the material sheet 80 is placed on the fixed mold 61, and heat is transferred from the material sheet 80 to the fixed mold 61 as the material sheet 80 comes into contact with the fixed mold 61, which has a relatively low temperature. As a result, the temperature of the material sheet 80 begins to decrease more rapidly than before.

[0072] However, in this embodiment, the material sheet main body 81 does not come into contact with the fixed mold 61. In addition, the covering sheet 82 is formed of a thermoplastic resin having a lower thermal conductivity than the material sheet main body 81. This suppresses the transfer of heat from the material sheet main body 81 to the fixed mold 61. As a result, the temperature of the material sheet 80 at time t2 when the movable mold 65 reaches the bottom dead center and the hot press molding is completed becomes higher than the first temperature T1.

[0073] 10, in the case of a comparative example material sheet 80A that has a material sheet main body 81 but does not have a covering sheet 82, both surfaces of the material sheet main body 81 are in direct contact with the fixed mold 61 and the movable mold 65. Therefore, compared to this embodiment, heat from the material sheet 80A is more likely to transfer to the fixed mold 61 and the movable mold 65. As a result, the temperature of the material sheet 80A becomes lower than the first temperature T1 before time t2 when the movable mold 65 reaches the bottom dead center.

[0074] The effects of this embodiment will be described. (3-1) With the surface of the material sheet 80 that comes into contact with the lower insert 62 covered with the cover sheet 82, the material sheet 80 and the cover sheet 82 are heated to a temperature T3 that is higher than the heat press temperature.

[0075] According to this method, the above-mentioned effects are achieved, and therefore the temperature of the material sheet 80 can be kept high when hot pressing, that is, the fluidity of the material sheet 80 can be kept high. Furthermore, a portion of the covering sheet 82 softened by the heat pressing is impregnated into the voids in the material sheet 80. This prevents the covering sheet 82 from forming a layer of only resin on one side of the separator 10. This prevents an increase in the contact resistance of the separator 10.

[0076] (3-2) With both sides of the material sheet 80 covered with the cover sheet 82, the material sheet 80 and the cover sheet 82 are heated to a temperature higher than the temperature of the heat press device 60. According to this method, the material sheet 80 does not come into contact with either the lower insert member 62 or the upper insert member 66. This suppresses the transfer of heat from the material sheet 80 to either the lower insert member 62 or the upper insert member 66. This makes it possible to maintain a higher temperature of the material sheet 80 during heat pressing, i.e., to maintain high fluidity of the material sheet 80.

[0077] Furthermore, by providing the cover sheet 82, it is possible to prevent a layer of only resin from being formed on both sides of the separator 10. <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0078] In the third embodiment, only the surface of the material sheet main body 81 that contacts the fixed mold 61 may be covered with the covering sheet 82. Even in this case, the material sheet main body 81 does not contact the fixed mold 61 when the material sheet 80 is placed on the fixed mold 61, and therefore the above-described effect (3-1) can be achieved.

[0079] In the second embodiment, if it is possible to irradiate only the second portion 11B with infrared rays, the mask 70 can be omitted. In the first and second embodiments, for example, a method of forming the coating material 12 into a strip or sheet shape can be employed without using the extrusion device 20. Even in this case, it is sufficient that the mass percent concentration of the solvent 15 in the material sheet 11 is set to 2 wt % or more and 8 wt % or less before the material sheet 11 is heat-pressed. [Explanation of symbols]

[0080] 10...Separator 10A…part 10a...gas flow path 10B...part 10b...coolant flow path 11...Material sheet 11A…First part 11B…Second part 12…Paint 13...Resin material 14...Filler 15...Solvent 20...Extrusion device 21...Cylinder 21a...Extrusion port 22...Screw 23...Hopper 24...Drive unit 30...Transportation device 31...Conveyor belt 40...Drying device 41...Heater 50...Cutting device 51...Cutting blade 60...Heat press device 61…Fixed type 62...Bottom nesting 63…Lower molding surface 64...Groove 65…Movable type 66...Top nesting 67…Upper molding surface 68...projection 70...Mask 80...Material sheet 80A...Material sheet 81...Material sheet body 82...Covering sheet 100...Manufacturing equipment

Claims

1. A method for manufacturing a fuel cell separator by hot press molding a material sheet in which a conductive filler is dispersed in a thermoplastic resin material using a hot press device, comprising: The method further includes an adjusting step of adjusting the fluidity of the material sheet before the material sheet is heat-pressed, the material sheet is formed from a paint formed by mixing the resin material, the filler, and a solvent, The mass percent concentration of the solvent in the paint is 30 wt % or more and 40 wt % or less, The material sheet is formed by extruding the paint into a strip or sheet shape using an extrusion device and then heating and drying the extrusion material using a drying device; In the adjusting step, a part of the solvent is volatilized by the drying device, so that the mass percent concentration of the solvent in the material sheet is set to 2 wt % or more and 8 wt % or less. A method for manufacturing a separator for a fuel cell.

2. A method for manufacturing a separator for a fuel cell by heat-pressing a material sheet in which a conductive filler is dispersed in a thermoplastic resin material using a heat press device, comprising: The method further includes an adjusting step of adjusting the fluidity of the material sheet before the material sheet is heat-pressed, the material sheet is formed from a paint formed by mixing the resin material, the filler, and a solvent, the material sheet has a first portion that faces a power generation unit of the fuel cell and a second portion that surrounds the first portion, In the adjusting step, the material sheet is heated so that the degree of heating of the first portion is smaller than that of the second portion, thereby increasing the proportion of the solvent contained in the first portion to be greater than the proportion of the solvent contained in the second portion, thereby increasing the fluidity of the first portion to be greater than the fluidity of the second portion; In the adjusting step, the mass percent concentration of the solvent in the material sheet is set to 2 wt % or more and 8 wt % or less. A method for manufacturing a separator for a fuel cell.

3. In the adjustment step, the material sheet is heated by irradiating the material sheet with infrared rays while the first portion is masked. A method for producing the fuel cell separator according to claim 2.

4. A method for manufacturing a separator for a fuel cell by heat-pressing a material sheet having a conductive filler dispersed in a thermoplastic resin material using a heat press device, comprising: The method further includes an adjusting step of adjusting the fluidity of the material sheet before the material sheet is heat-pressed, The material sheet is porous, In the adjusting step, a surface of the material sheet facing the fixed mold of the heat press device is covered with a covering sheet formed of a thermoplastic resin having a lower thermal conductivity than the material sheet, and the material sheet and the covering sheet are heated to a temperature higher than the temperature of the heat press device. A method for manufacturing a separator for a fuel cell.

5. In the adjusting step, both sides of the material sheet are covered with the covering sheet, and the material sheet and the covering sheet are heated to a temperature higher than the temperature of the heat press device. A method for producing the fuel cell separator according to claim 4.

6. A method for manufacturing a separator for a fuel cell by heat-pressing a material sheet having a conductive filler dispersed in a thermoplastic resin material using a heat press device, comprising: The method further includes an adjusting step of adjusting the fluidity of the material sheet before the material sheet is heat-pressed, the material sheet has a first portion that faces a power generation unit of the fuel cell and a second portion that surrounds the first portion, In the adjusting step, the fluidity of the first portion is made higher than the fluidity of the second portion. A method for manufacturing a separator for a fuel cell.

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