Manufacturing method of fuel cell separator

Abstract

To provide a manufacturing method of a fuel cell separator capable of reducing variations in thickness of the separator.SOLUTION: A separator manufacturing method includes a heating step, a press step and a channel molding step. In the heating step, a sheet material formed by dispersing carbon material particles in a thermoplastic resin is heated to a temperature higher than a fusing point of the thermoplastic resin. In the press step, the sheet material heated in the heating step is pressed using a first metal die, such that the sheet material is molded into a predetermined thickness and then, the sheet material is cooled together with the first metal die. In the channel molding step, the sheet material pressed by the first metal die is pressed using a second metal die, thereby molding a gas channel in the sheet material. A sheet material whose content of the thermoplastic resin is 20 wt.% or more and 30 wt.% or less and content of the carbon material particles is 70 wt.% or more and 80 wt.% or less is used.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Conventionally, a polymer electrolyte fuel cell is constructed by stacking a plurality of power generation cells. The power generation cell includes a power generation section having a membrane electrode assembly and two separators that sandwich the power generation section. The separators are provided with a plurality of gas flow paths through which reactant gases flow.

[0003] Patent Document 1 discloses a method for manufacturing a fuel cell separator made of a mixture of carbon powder and a thermoplastic resin. In this method, the mixture is first extruded to form a sheet-like molded product. Then, a pressure roller having grooves corresponding to the shape of the gas flow passages is used to transfer the grooves to the sheet-like molded product. In this way, a separator provided with gas flow passages is manufactured. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-198062 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the thickness of such a separator varies greatly across the entire separator, the contact area between the separator and the power generation section may decrease, which may increase the contact resistance between them. For this reason, in order to improve the performance of fuel cells, it is desirable to reduce the variation in the thickness of the separator. [Means for solving the problem]

[0006] A method for manufacturing a fuel cell separator for solving the above problem is a method for manufacturing a fuel cell separator comprising a thermoplastic resin and electrically conductive carbon material particles, and having a gas flow path through which a reactive gas flows, the method comprising: a heating step of heating a sheet material formed by dispersing the carbon material particles in the thermoplastic resin; a pressing step of pressing the sheet material heated in the heating step using a first mold to form the sheet material to a predetermined thickness, and then cooling the sheet material together with the first mold; and a flow path forming step of pressing the sheet material pressed by the first mold using a second mold to form the gas flow path in the sheet material, wherein the sheet material has a thermoplastic resin content of 20% by weight to 30% by weight and a carbon material particle content of 70% by weight to 80% by weight, and the heating step heats the sheet material to a temperature higher than the melting point of the thermoplastic resin.

[0007] According to this method, a sheet material is heated to a temperature higher than the melting point of a thermoplastic resin in a heating step, and is molded to a predetermined thickness in a pressing step and cooled. Then, a gas flow path is molded in the sheet material in a flow path molding step.

[0008] Here, the content of thermoplastic resin in the sheet material is 20% by weight or more and 30% by weight or less, and the content of carbon material particles is 70% by weight or more and 80% by weight or less. By heating such a sheet material to a temperature higher than the melting point of the thermoplastic resin, it is possible to increase the fluidity of the thermoplastic resin and suppress deformation of the sheet material compared to the case of heating to a temperature below the melting point. This makes it possible to reduce the variation in thickness of the sheet material that has been subjected to the pressing process. Then, in the flow path forming process, gas flow paths are formed in the sheet material with reduced thickness variation. Therefore, it is possible to reduce the variation in thickness throughout the separator. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a fuel cell provided with a fuel cell separator according to an embodiment. [Diagram 2] FIG. [Diagram 3] 3 is a flowchart showing the steps of a method for manufacturing a fuel cell separator in order. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. 11 is a cross-sectional view showing a state before a second mold is clamped in a flow path molding step. [Figure 9] 13 is a cross-sectional view showing a state after the second mold is clamped in a flow path molding step. FIG. [Figure 10] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, one embodiment of a method for producing a fuel cell separator will be described with reference to FIGS. In each drawing, some of the components may be exaggerated or simplified, and the dimensional ratios of each component may differ from the actual ratios.

[0011] (Fuel cell configuration) First, a fuel cell in which a fuel cell separator is provided will be described. As shown in FIG. 1, the fuel cell includes a cell stack 10 in which a plurality of power generating cells 11 are stacked.

[0012] The power generating cell 11 includes a sheet-like membrane electrode gas diffusion layer assembly 20 and two separators 30 that sandwich the membrane electrode gas diffusion layer assembly 20 in the thickness direction. The membrane electrode gas diffusion layer assembly 20 includes a membrane electrode assembly 21, an anode gas diffusion layer 25, and a cathode gas diffusion layer .

[0013] The membrane electrode assembly 21 includes an electrolyte layer 22 formed of, for example, a solid polymer membrane, and an anode electrode layer 23 and a cathode electrode layer 24 that sandwich the electrolyte layer 22 in the thickness direction.

[0014] The anode gas diffusion layer 25 covers the surface of the anode electrode layer 23 opposite the electrolyte layer 22. The cathode gas diffusion layer 26 covers the surface of the cathode electrode layer 24 opposite the electrolyte layer 22. The anode gas diffusion layer 25 and the cathode gas diffusion layer 26 are both made of carbon fiber, for example.

[0015] (Configuration of separator 30) One separator 30 in the power generating cell 11 is provided on the surface of the anode gas diffusion layer 25 opposite the anode electrode layer 23. The other separator 30 in the power generating cell 11 is provided on the surface of the cathode gas diffusion layer 26 opposite the cathode electrode layer 24.

[0016] The separator 30 has, for example, a rectangular plate shape. The separator 30 is made of a thermoplastic resin and electrically conductive carbon material particles. Inside the separator 30, the carbon material particles are dispersed in the thermoplastic resin throughout the thickness direction.

[0017] 2, the separator 30 has a plurality of gas flow paths 31 extending in parallel with each other at intervals, and a plurality of ribs 32 extending along the gas flow paths 31 between adjacent gas flow paths 31. That is, the separator 30 has the gas flow paths 31 and the ribs 32 alternately arranged in parallel.

[0018] The gas flow passages 31 are groove-shaped and open toward the membrane electrode gas diffusion layer assembly 20. Hydrogen gas as a reactant gas flows through the gas flow passages 31 of one separator 30. Air as a reactant gas flows through the gas flow passages 31 of the other separator 30.

[0019] In the power generation cell 11, one of the separators 30 is disposed so that the top surface of each rib 32 is in contact with the anode gas diffusion layer 25. This allows hydrogen gas flowing through each gas flow channel 31 to be supplied to the anode electrode layer 23 through the anode gas diffusion layer 25.

[0020] The other separator 30 is disposed so that the top surface of each rib 32 is in contact with the cathode gas diffusion layer 26. This allows the air flowing through each gas flow passage 31 to be supplied to the cathode electrode layer 24 through the cathode gas diffusion layer 26.

[0021] In the membrane electrode assembly 21, hydrogen gas supplied to the anode electrode layer 23 and air supplied to the cathode electrode layer 24 undergo an electrochemical reaction to generate electricity. (Method of manufacturing separator 30) Next, a method for producing the separator 30 will be described.

[0022] As shown in FIG. 3, in the method for producing the separator 30, a heating step, a transporting step, a pressing step, a first cooling step, a flow path forming step, and a second cooling step are performed in this order. As shown in FIGS. 4 to 10, in manufacturing the separator 30, the separator 30 is manufactured from a sheet material 40 formed by dispersing carbon material particles in a thermoplastic resin.

[0023] Here, when the total amount of the sheet material 40 is taken as 100% by weight, the sheet material 40 contains, for example, 25% by weight of thermoplastic resin and 75% by weight of carbon material particles. As the thermoplastic resin, one material may be used alone or two or more materials may be used in appropriate combination from polyphenylene sulfide (PPS), polyamide (PA), polytetrafluoroethylene (PTFE), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene (PP), polyethersulfone (PES), polyphenylene ether (PPE), polycarbonate (PC), etc. The thermoplastic resin in this embodiment is polyamide. The melting point of polyamide is about 280°C.

[0024] As the carbon material particles, for example, one type of material from natural graphite, artificial graphite, and expanded graphite can be used alone, or two or more types of materials can be used in appropriate combination. Examples of natural graphite include flake graphite, lump graphite, and soil graphite. The carbon material particles of this embodiment are flake graphite. The average particle diameter of the flake graphite is, for example, 40 μm.

[0025] Although not shown in the drawings, when forming the sheet material 40, a uniform powder composition is first obtained using a pulverizer that grinds thermoplastic resin particles and carbon material particles together by friction or impact force. The obtained powder composition is then heated and melted, and cooled and solidified using a double belt press device including a pressurized heating section and a pressurized cooling section, thereby forming the sheet material 40.

[0026] Each step in the method for producing the separator 30 will be described below. (Heating process) 4, in the heating step, first, the sheet material 40 is sandwiched between two metal plates 100 in the thickness direction. Then, the sheet material 40 sandwiched between the two metal plates 100 is heated together with the two metal plates 100 in a heating furnace 110. By heating the sheet material 40 in the heating furnace 110, the sheet material 40 is easily heated uniformly.

[0027] In the heating step, the sheet material 40 is heated to a temperature higher than the melting point of the thermoplastic resin. This causes the thermoplastic resin to melt. In this embodiment, the sheet material 40 is heated to 300°C to 350°C.

[0028] The metal plate 100 may be made of a metal material such as carbon steel, which has a relatively low thermal conductivity and thermal expansion coefficient. A release layer 101 having releasability is provided on the surface of each metal plate 100 facing the sheet material 40. The release layer 101 is, for example, a coating layer containing a fluorine compound.

[0029] (transfer process) 5, in the transfer step, the sheet material 40 heated in the heating step is transferred from the heating furnace 110 to the first mold 130 while being contained in a thermally insulating heat-retaining container 120. At this time, the sheet material 40 is transferred while being contained in the heat-retaining container 120 while being sandwiched between two metal plates 100.

[0030] (Pressing process) As shown in FIG. 6, in the pressing step, the sheet material 40 is pressed by a first die 130.

[0031] Here, the configuration of the first mold 130 will be described. The first mold 130 includes a fixed mold 131 and a movable mold 134 that is movable toward and away from the fixed mold 131. The fixed mold 131 and the movable mold 134 are provided with molding surfaces 132 and 135 that face each other and mold the sheet material 40, respectively. In addition, heaters 133 and 136 for heating the fixed mold 131 and the movable mold 134 are provided inside the fixed mold 131 and the movable mold 134, respectively. In addition, cooling channels 137 and 138 through which a refrigerant flows for cooling the fixed mold 131 and the movable mold 134 are provided inside the fixed mold 131 and the movable mold 134, respectively.

[0032] In the pressing process, an elastic member 140 is interposed between the fixed die 131 and the metal plate 100. Similarly, an elastic member 140 is interposed between the movable die 134 and the metal plate 100. The elastic member 140 is in the form of a sheet configured to be elastically deformable. The elastic member 140 is configured to include, for example, glass fiber and fluororubber.

[0033] The first mold 130 is heated by the heaters 133, 136 before the pressing step is started. That is, in the pressing step, the sheet material 40 is pressed in a state in which the first mold 130 is heated. In the pressing step, the first mold 130 is preferably heated to, for example, 100°C to 350°C. In this embodiment, the first mold 130 is heated to a temperature higher than about 280°C, which is the melting point of the thermoplastic resin, more specifically, to 330°C to 350°C.

[0034] In the pressing process, the sheet material 40 heated in the heating process is pressed together with the two metal plates 100 by the first die 130, so that the sheet material 40 is formed to a predetermined thickness. In this embodiment, the predetermined thickness refers to the thickness of the separator 30. In the pressing process, the sheet material 40 is pressed in a state in which the elastic member 140 is interposed between each metal plate 100 and the first die 130, and in a state in which the release layer 101 is interposed between each metal plate 100 and the sheet material 40.

[0035] In the pressing process, after the sheet material 40 is formed to the above-mentioned predetermined thickness, the sheet material 40 is cooled together with the first die 130. Such cooling is performed by flowing a refrigerant through the cooling passages 137 and 138 of the first die 130. The cooling of the first die 130 is performed in a state in which the first die 130 is clamped.

[0036] Cooling the sheet material 40 reduces the fluidity of the thermoplastic resin. This makes it easier to maintain the shape of the sheet material 40 after the pressing process. That is, in the pressing process, after the sheet material 40 is pressed by the first die 130, the sheet material 40 is cooled until the thermoplastic resin solidifies to such an extent that the shape of the sheet material 40 is maintained.

[0037] (1st cooling process) As shown in FIG. 7, in the first cooling step, the sheet material 40 that has been subjected to the pressing step is cooled and solidified in a state in which it is sandwiched between two first metal members 150 in the thickness direction.

[0038] In the first cooling step, the sheet material 40 is air-cooled at room temperature in a state where it is sandwiched between the two first metal members 150. Thereby, the sheet material 40 is cooled to, for example, 100° C. or lower.

[0039] The first metal member 150 has, for example, a plate shape. A metal material having a relatively high thermal conductivity and a relatively small thermal expansion coefficient is preferable as the first metal member 150. The material of the first metal member 150 may be, for example, copper or a copper alloy.

[0040] (Flow path forming process) As shown in FIG. 8, in the flow passage forming step, the sheet material 40 is pressed by a second die 160.

[0041] Here, the configuration of the second mold 160 will be described. The second mold 160 includes a fixed mold 161 and a movable mold 164 that is provided so as to be movable toward and away from the fixed mold 161. The fixed mold 161 and the movable mold 164 are provided with molding surfaces 162 and 165 that face each other and mold the sheet material 40, respectively. The molding surfaces 162 and 165 are provided with a plurality of grooves 162a and 165a for transferring the gas flow paths 31 and the ribs 32 to the sheet material 40, respectively. In addition, the fixed mold 161 and the movable mold 164 are provided with heaters 163 and 166 for heating them, respectively. In addition, the fixed mold 161 and the movable mold 164 are provided with cooling paths 167 and 168 through which a refrigerant flows for cooling them, respectively.

[0042] As shown in FIG. 9, in the flow passage forming step, the sheet material 40 is pressed by a second die 160, so that the gas flow passages 31 and the ribs 32 are formed in the sheet material 40. The second mold 160 is heated by the heaters 163, 166 before the flow path forming step is started. That is, in the flow path forming step, the sheet material 40 is pressed in a state in which the second mold 160 is heated. In the flow path forming step, it is preferable that the second mold 160 is heated to a temperature lower than the melting point of the thermoplastic resin, more specifically, to 50°C to 160°C. In this embodiment, the second mold 160 is heated to a temperature near about 90°C, which is the glass transition temperature of the thermoplastic resin.

[0043] (Second cooling process) As shown in FIG. 10, in the second cooling step, the sheet material 40 that has been subjected to the flow passage forming step is cooled and solidified in a state in which it is sandwiched between two second metal members 170 in the thickness direction.

[0044] The second metal member 170 has, for example, a plate shape. A metal material having a relatively high thermal conductivity and a relatively small thermal expansion coefficient is preferable for the second metal member 170. The material for the second metal member 170 may be, for example, copper or a copper alloy.

[0045] In the second cooling step, the sheet material 40 is air-cooled at room temperature in a state where it is sandwiched between the two second metal members 170. Thereby, the sheet material 40 is cooled to a temperature near room temperature, for example.

[0046] Although not shown in the drawings, after the second cooling step, a punching step is performed in which the sheet material 40 is punched by a press device. The punching step includes, for example, a step of providing through holes in the sheet material 40 and a step of trimming the outer periphery of the sheet material 40.

[0047] The operation and effects of this embodiment will be described. (1) The method for manufacturing the separator 30 includes a heating step, a pressing step, and a flow path forming step. In the heating step, the sheet material 40 formed by dispersing carbon material particles in a thermoplastic resin is heated to a temperature higher than the melting point of the thermoplastic resin. In the pressing step, the sheet material 40 heated in the heating step is pressed using a first die 130 to form the sheet material 40 to a predetermined thickness, and then the sheet material 40 is cooled together with the first die 130. In the flow path forming step, the sheet material 40 pressed by the first die 130 is pressed using a second die 160 to form the gas flow paths 31 in the sheet material 40. The sheet material 40 used has a thermoplastic resin content of 25% by weight and a carbon material particle content of 75% by weight.

[0048] According to this method, the sheet material 40 is heated to a temperature higher than the melting point of the thermoplastic resin in the heating step, and is molded to a predetermined thickness in the pressing step and cooled. Then, the gas flow paths 31 are molded in the sheet material 40 in the flow path molding step.

[0049] Here, the content of the thermoplastic resin in the sheet material 40 is 20% by weight or more and 30% by weight or less, and the content of the carbon material particles is 70% by weight or more and 80% by weight or less. By heating such a sheet material 40 to a temperature higher than the melting point of the thermoplastic resin, it is possible to increase the fluidity of the thermoplastic resin and suppress the deformation of the sheet material 40 compared to the case of heating to a temperature below the melting point. This makes it possible to reduce the variation in thickness of the sheet material 40 that has been subjected to the pressing process. Then, in the flow path forming process, the gas flow paths 31 are formed in the sheet material 40 with reduced thickness variation. Therefore, it is possible to reduce the variation in thickness in the entire separator 30.

[0050] Furthermore, since the fluidity of the thermoplastic resin is increased in the heating step, the press load of the first die 130 can be reduced in the pressing step. Furthermore, by heating the sheet material 40 to a temperature higher than the melting point of the thermoplastic resin, the thermoplastic resin is prevented from being unevenly distributed inside the separator 30. This makes it possible to prevent cracks and pinholes from occurring in the separator 30.

[0051] (2) In the heating step, the sheet material 40 is heated in the heating furnace 110. The method for producing the separator 30 includes a transfer step of transferring the sheet material 40 from the heating furnace 110 to the first die 130 between the heating step and the pressing step.

[0052] For example, when the heating step is performed by heating the first mold 130, it is necessary to heat the first mold 130 to a temperature higher than the melting point of the thermoplastic resin. In this case, it takes a long time to cool the first mold 130 that has been heated to a temperature higher than the melting point in the pressing step.

[0053] In this regard, according to the above method, the sheet material 40 is heated by equipment separate from the first mold 130 and then transferred to the first mold 130. Therefore, it is not necessary to heat the first mold 130 to a temperature higher than the melting point. This makes it possible to shorten the time required to cool the sheet material 40 in the pressing process. Therefore, it is possible to suppress a decrease in the productivity of the separator 30.

[0054] (3) In the transfer step, the sheet material 40 is transferred while being contained in the heat-retaining container 120 . According to this method, it is possible to suppress a decrease in temperature of the sheet material 40 while the sheet material 40 is being transferred from the heating furnace 110 to the first die 130. This makes it possible to suppress a decrease in the fluidity of the thermoplastic resin. This makes it possible to reduce the press load of the first die 130 in the press process.

[0055] (4) In the pressing step, the sheet material 40 is pressed with the first die 130 in a heated state. According to this method, it is possible to suppress a decrease in temperature of the sheet material 40 during the pressing process until the sheet material 40 placed on the first die 130 is pressed. This makes it possible to suppress a decrease in the fluidity of the thermoplastic resin. This makes it possible to reduce the pressing load of the first die 130 during the pressing process.

[0056] (5) In the heating step, the sheet material 40 is sandwiched between two metal plates 100 in the thickness direction, and the sheet material 40 is heated together with the two metal plates 100. In the pressing step, the sheet material 40 is pressed via two metal plates 100.

[0057] According to this method, in the heating step, the sheet material 40 is heated together with the two metal plates 100. Then, in the pressing step, the sheet material 40 is pressed via the two heated metal plates 100. This makes it possible to suppress a decrease in the temperature of the sheet material 40 before the pressing step is performed. This makes it possible to reduce the pressing load of the first die 130 in the pressing step.

[0058] Furthermore, according to the above method, in both the heating step and the pressing step, the sheet material 40 is sandwiched between the two metal plates 100. Therefore, deformation of the sheet material 40 due to thermal expansion in the heating step and deformation of the sheet material 40 due to thermal contraction in the pressing step can be suppressed.

[0059] (6) In the pressing step, the sheet material 40 is pressed in a state in which the elastic members 140 are interposed between each of the two metal plates 100 and the first die 130. According to this method, the elastic member 140 is elastically deformed by the press load of the first die 130, and the press load is easily applied uniformly to the entire sheet material 40 via the two metal plates 100. Therefore, it is possible to further reduce the variation in thickness of the sheet material 40 that has been subjected to the press process.

[0060] (7) In the pressing step, the sheet material 40 is pressed with the release layer 101 having releasability interposed between each of the two metal plates 100 and the sheet material 40 . According to this method, since the release layer 101 is interposed between each metal plate 100 and the sheet material 40 after the pressing process, it is possible to improve the releasability of each metal plate 100 from the sheet material 40. Therefore, the separator 30 can be easily manufactured.

[0061] (8) The manufacturing method of the separator 30 includes a first cooling process between the pressing process and the flow path forming process, in which the sheet material 40 is sandwiched between two first metal members 150 in the thickness direction and cooled to solidify.

[0062] According to this method, the sheet material 40 dissipates heat through the two first metal members 150, so that the thermoplastic resin can be solidified quickly after the pressing process. This allows the flow passage molding process to start early, and therefore the productivity of the separator 30 can be improved.

[0063] Furthermore, according to the above method, since the sheet material 40 is sandwiched between the two first metal members 150 in the first cooling step, deformation of the sheet material 40 due to thermal contraction can be suppressed. (9) In the flow path forming step, the sheet material 40 is pressed in a state where the second die 160 is heated to a temperature lower than the melting point of the thermoplastic resin.

[0064] According to this method, it is possible to soften the thermoplastic resin while maintaining the dimensional accuracy of the sheet material 40 molded to a predetermined thickness. This makes it possible to easily mold the gas flow passages 31 in the sheet material 40 in the flow passage molding step.

[0065] (10) The method for manufacturing the separator 30 includes, after the flow path forming step, a second cooling step of cooling and solidifying the sheet material 40 in a state where the sheet material 40 is sandwiched between two second metal members 170 in the thickness direction.

[0066] According to this method, the sheet material 40 dissipates heat via the two second metal members 170, so that the thermoplastic resin can be solidified quickly after the flow passages are formed, and therefore the productivity of the separator 30 can be improved.

[0067] Furthermore, according to the above method, since the sheet material 40 is sandwiched between the two second metal members 170 in the second cooling step, deformation of the sheet material 40 due to thermal contraction can be suppressed. (11) A homogeneous powder composition obtained using a grinder for grinding thermoplastic resin particles and carbon material particles is heated and melted using a double belt press device including a pressurized heating section and a pressurized cooling section, and then cooled and solidified to form a sheet material 40.

[0068] According to this method, the carbon material particles are connected to each other in a highly controlled composite structure, so that the sheet material 40 having high thermal conductivity and electrical conductivity is formed. According to this method for manufacturing a separator using the sheet material 40, the composite structure of the sheet material 40 can be maintained, and the thermal and electrical performance can be reflected in the separator 30 without impairing the performance.

[0069] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0070] The second metal member 170 may be made of a metal material other than copper or a copper alloy. The second cooling step may be omitted. In this case, for example, the sheet material 40 may be cooled and solidified by cooling the second mold 160.

[0071] In the flow path forming step, the sheet material 40 may be pressed by the second die 160 without the second die 160 being heated. The first metal member 150 may be made of a metal material other than copper or a copper alloy.

[0072] The first cooling step may be omitted. In this case, for example, the sheet material 40 may be cooled and solidified by cooling the first mold 130. The release layer 101 may be, for example, a release sheet provided between the metal plate 100 and the sheet material 40 separately from the metal plate 100 .

[0073] The release layer 101 can be omitted from the metal plate 100. In the pressing process, the two elastic members 140 may be omitted. In the heating step, the two metal plates 100 may be omitted and only the sheet material 40 may be heated. In this case, in the pressing step, the sheet material 40 may be directly pressed by the first die 130.

[0074] In the pressing step, the sheet material 40 may be pressed by the first die 130 without the first die 130 being heated. In the transfer step, the heat-retaining container 120 can be omitted.

[0075] In the heating step, the sheet material 40 may be heated by heating the first mold 130 with heaters 133 and 136 instead of the heating furnace 110. In this case, it is preferable that the sheet material 40 is heated with the first mold 130 being clamped. [Explanation of symbols]

[0076] 30…Separator 31...Gas flow path 40…Sheet material 100...Metal plate 101...Release layer 110...Heating furnace 120…Thermos container 130…First mold 140...Elastic member 150…First metal member 160…Second mold 170...Second metal member

Claims

1. A method for manufacturing a separator for a fuel cell, the separator comprising a thermoplastic resin and electrically conductive carbon material particles, and having a gas flow passage through which a reaction gas flows, comprising the steps of: a heating step of heating a sheet material formed by dispersing the carbon material particles in the thermoplastic resin; a pressing step of pressing the sheet material heated in the heating step with a first die to form the sheet material into a predetermined thickness, and then cooling the sheet material together with the first die; a flow passage forming step of pressing the sheet material pressed by the first die with a second die to form the gas flow passage in the sheet material, The sheet material has a thermoplastic resin content of 20% by weight or more and 30% by weight or less, and a carbon material particle content of 70% by weight or more and 80% by weight or less, In the heating step, the sheet material is heated to a temperature higher than the melting point of the thermoplastic resin, In the pressing step, the sheet material is pressed in a heated state with the first die, In the flow channel forming step, the sheet material is pressed in a state where the second mold is heated to a temperature lower than the melting point of the thermoplastic resin. A method for manufacturing a separator for a fuel cell.

2. In the heating step, the sheet material is heated in a heating furnace, A transfer step of transferring the sheet material from the heating furnace to the first die is provided between the heating step and the pressing step. A method for producing the fuel cell separator according to claim 1.

3. In the transporting step, the sheet material is transported in a state where it is contained in a heat-insulating container. A method for producing the fuel cell separator according to claim 2.

4. In the heating step, the sheet material is sandwiched between two metal plates in a thickness direction, and the sheet material is heated together with the two metal plates; In the pressing step, the sheet material is pressed via the two metal plates. A method for producing the fuel cell separator according to any one of claims 1 to 3.

5. In the pressing step, the sheet material is pressed in a state in which an elastic member is interposed between each of the two metal plates and the first die. A method for producing the fuel cell separator according to claim 4.

6. In the pressing step, the sheet material is pressed in a state in which a release layer having a releasability is interposed between each of the two metal plates and the sheet material. A method for producing a fuel cell separator according to claim 4 or 5.

7. A cooling process is provided between the pressing process and the flow path forming process, in which the sheet material is sandwiched between two metal members in a thickness direction and cooled to be solidified. A method for producing a fuel cell separator according to any one of claims 1 to 6.

8. a cooling step of cooling and solidifying the sheet material while sandwiched between two metal members in a thickness direction after the flow path forming step; A method for producing the fuel cell separator according to any one of claims 1 to 7.

9. a homogeneous powder composition obtained by using a pulverizer for pulverizing the thermoplastic resin particles and the carbon material particles is heated and melted using a double belt press device including a pressurizing heating section and a pressurizing cooling section, and then cooled and solidified to form the sheet material; A method for producing a fuel cell separator according to any one of claims 1 to 8.

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