Method for manufacturing a fuel cell separator

Abstract

A method for manufacturing a fuel cell separator includes: heating a sheet; pressing the sheet using a first mold so that the sheet is formed into a predetermined thickness; cooling the sheet that has been formed into a predetermined thickness together with the first mold; and pressing the sheet that has undergone cooling using a second mold so as to form gas channels in the sheet. In the sheet, the content of the thermoplastic resin is greater than or equal to 20% by weight and less than or equal to 30% by weight, and the content of the carbon material particles is greater than or equal to 70% by weight and less than or equal to 80% by weight. Heating the sheet includes heating the sheet to a temperature higher than the melting point of the thermoplastic resin.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a fuel cell separator plate. Background Art

[0002] Conventionally, a polymer electrolyte fuel cell includes stacked power generation cells. Each power generation cell includes a power generation part having a membrane electrode assembly and two separator plates holding the power generation part. Each separator plate includes gas channels through which reaction gas flows.

[0003] Japanese Patent Application Laid-Open No. 2002-198062 discloses a method for manufacturing a fuel cell separator plate, which includes a mixture of carbon powder and a thermoplastic resin. In this manufacturing method, the mixture is extruded to form a sheet molded product. Then, a roll having grooves formed corresponding to the gas channels is used to transfer the grooves to the sheet molded product. Thus, a separator plate including gas channels is manufactured.

[0004] In such a separator plate, when the thickness variation of the entire separator plate is large, the contact area between the separator plate and the power generation part may be reduced, increasing the contact resistance therebetween. Therefore, in order to improve the performance of the fuel cell, it is desirable to reduce the variation in the thickness of the separator plate. Summary of the Invention

[0005] The present invention content is provided to introduce some concepts in a simplified form, which will be further described in the following detailed description. The present invention content is not intended to indicate the key features or essential features of the claimed subject matter, nor is it intended to assist in determining the scope of the claimed subject matter.

[0006] Provided is a method for manufacturing a fuel cell separator plate that solves the above problems. The fuel cell separator plate is made of a material including a thermoplastic resin and conductive carbon material particles. The fuel cell separator plate includes gas channels through which reaction gas flows. The method includes: heating a sheet made of a material including a thermoplastic resin and conductive carbon material particles dispersed in the thermoplastic resin; pressing the sheet heated in the heating using a first mold to form the sheet having a predetermined thickness; cooling the sheet that has been formed to have the predetermined thickness by pressing using the first mold together with the first mold; and pressing the sheet that has undergone the cooling using a second mold to form the gas channels in the sheet. In the sheet, the content of the thermoplastic resin is greater than or equal to 20% by weight and less than or equal to 30% by weight, and the content of the carbon material particles is greater than or equal to 70% by weight and less than or equal to 80% by weight. Heating the sheet includes heating the sheet to a temperature higher than the melting point of the thermoplastic resin.

[0007] Other features and aspects will be apparent from the following detailed description, drawings, and technical solutions. Description of the Drawings

[0008] Figure 1 is a cross-sectional view schematically showing the structure of a fuel cell provided with a fuel cell separator according to an embodiment.

[0009] Figure 2 is a perspective view showing the fuel cell separator.

[0010] Figure 3 is a flowchart sequentially showing the steps of a method for manufacturing a fuel cell separator.

[0011] Figure 4 is a cross-sectional view showing the heating step.

[0012] Figure 5 is a cross-sectional view showing the transporting step.

[0013] Figure 6 is a cross-sectional view showing the pressing step.

[0014] Figure 7 is a cross-sectional view showing the first cooling step.

[0015] Figure 8 is a cross-sectional view showing the state where the second mold is not yet locked in the channel forming step.

[0016] Figure 9 is a cross-sectional view showing the state where the second mold has been locked in the channel forming step.

[0017] Figure 10 is a cross-sectional view showing the second cooling step.

[0018] Throughout the drawings and the detailed description, like reference numerals refer to like elements. The drawings may not be drawn to scale, and for clarity, illustration, and convenience, the relative dimensions, proportions, and depictions of the elements in the drawings may be exaggerated. Detailed Description

[0019] This detailed description provides a comprehensive understanding of the described method, apparatus, and / or system. Variations and equivalents of the described method, apparatus, and / or system will be apparent to those skilled in the art. The sequence of operations is exemplary, and except for operations that must be performed in a specific order, it will be apparent to those skilled in the art that they can be changed. Descriptions of functions and structures known to those skilled in the art may be omitted.

[0020] Exemplary embodiments may have different forms and are not limited to the examples described. However, the described examples are detailed and complete and convey the full scope of the disclosure to those skilled in the art.

[0021] In this specification, "at least one of A and B" should be understood to mean "only A, only B, or both A and B".

[0022] Now, a method of manufacturing a fuel cell separator according to an embodiment will be described with reference to Figures 1 to 10 the drawings.

[0023] Some parts of the components in the drawings may be exaggerated or simplified. In addition, the dimensional ratios of the components in the drawings may be different from the actual dimensional ratios.

[0024] Structure of a fuel cell

[0025] First, a fuel cell provided with a fuel cell separator will be described.

[0026] As Figure 1 shown, the fuel cell includes a cell stack 10 having stacked power generation cells 11.

[0027] Each power generation cell 11 includes a sheet-like membrane electrode gas diffusion layer assembly 20 and two separators 30 that hold the membrane electrode gas diffusion layer assembly 20 in the thickness direction.

[0028] 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 26.

[0029] The membrane electrode assembly 21 includes an electrolyte layer 22, an anode electrode layer 23, and a cathode electrode layer 24. The electrolyte layer 22 is, for example, a solid polymer membrane. The anode electrode layer 23 and the cathode electrode layer 24 hold the electrolyte layer 22 in the thickness direction.

[0030] The anode gas diffusion layer 25 covers the surface of the anode electrode layer 23 opposite to the electrolyte layer 22. The cathode gas diffusion layer 26 covers the surface of the cathode electrode layer 24 opposite to the electrolyte layer 22. The anode gas diffusion layer 25 and the cathode gas diffusion layer 26 are made of, for example, carbon fiber.

[0031] Structure of the separator 30

[0032] One separator 30 in the power generation cell 11 is located on the surface of the anode gas diffusion layer 25 opposite to the anode electrode layer 23. The other separator 30 in the power generation cell 11 is located on the surface of the cathode gas diffusion layer 26 opposite to the cathode electrode layer 24.

[0033] The separator 30 has, for example, a rectangular shape. Each separator 30 is made of a material containing a thermoplastic resin and conductive carbon material particles. In the separator 30, the carbon material particles are dispersed throughout the thermoplastic resin in the thickness direction.

[0034] As Figure 2As shown, the separator 30 includes gas channels 31 and ribs 32. The gas channels 31 extend in parallel and are spaced apart from each other. The ribs 32 all extend between adjacent gas channels 31 along the gas channels 31. That is, the separator 30 includes gas channels 31 and ribs 32 that are alternately arranged in parallel.

[0035] Each gas channel 31 has the shape of a groove that opens toward the membrane electrode gas diffusion layer assembly 20. Hydrogen (reaction gas) flows through the gas channels 31 of one separator 30. Air (reaction gas) flows through the gas channels 31 of the other separator 30.

[0036] In the power generation cell 11, one separator 30 is configured such that the top surfaces of the respective ribs 32 are in contact with the anode gas diffusion layer 25. This allows the hydrogen flowing through the gas channels 31 to be supplied to the anode electrode layer 23 through the anode gas diffusion layer 25.

[0037] The other separator 30 is configured such that the top surfaces of the respective ribs 32 are in contact with the cathode gas diffusion layer 26. This allows the air flowing through the gas channels 31 to be supplied to the cathode electrode layer 24 through the cathode gas diffusion layer 26.

[0038] In the membrane electrode assembly 21, the hydrogen supplied to the anode electrode layer 23 and the air supplied to the cathode electrode layer 24 undergo an electrochemical reaction to generate electricity.

[0039] Method for manufacturing the separator 30

[0040] Now, a method for manufacturing each separator 30 will be described.

[0041] As Figure 3 shown, the method for manufacturing the separator 30 includes a heating step, a conveying step, a pressing step, a first cooling step, a channel forming step, and a second cooling step that are performed in sequence.

[0042] As Figures 4 to 10 shown, the separator 30 is manufactured from a sheet 40. The sheet 40 is made of a material containing a thermoplastic resin and conductive carbon material particles dispersed in the thermoplastic resin.

[0043] In the case where the total weight of the sheet 40 is 100% by weight, the sheet 40 contains, for example, 25% by weight of the thermoplastic resin and 75% by weight of the carbon material particles.

[0044] For example, one of polyphenylene sulfide (PPS), polyamide (PA), polytetrafluoroethylene (PTFE), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene (PP), polyethersulfone (PES), polyphenylene ether (PPE), and polycarbonate (PC) can be used alone as the thermoplastic resin. Alternatively, two or more of these materials can be used in combination as the thermoplastic resin. The thermoplastic resin of the present embodiment is polyamide. The melting point of the polyamide is about 280 °C.

[0045] For example, one of natural graphite, artificial graphite, and expanded graphite can be used as the carbon material particles. Alternatively, two or more of these materials can be used in combination as the carbon material particles. Examples of natural graphite include flake graphite, massive graphite, and earthy graphite. The carbon material particles of the present embodiment are flake graphite. The flake graphite has an average particle size of, for example, 40 μm.

[0046] Although not shown in the drawings, in the case of forming the sheet 40, first, a grinding machine that grinds the powder by frictional force or impact force is used to grind the thermoplastic resin particles and the carbon material particles to obtain a uniform powder composition. In addition, a twin-belt pressing system including a pressure heating section and a pressure cooling section is used to heat and melt the obtained powder composition, and then cool and solidify the powder composition. Thereby, the sheet 40 is formed.

[0047] Now, the steps in the method of manufacturing the separator 30 will be described.

[0048] Heating step

[0049] As Figure 4 shown, in the heating step, first, the sheet 40 is held between two metal plates 100 in the thickness direction. Then, the two metal plates 100 and the sheet 40 held between the two metal plates 100 are heated in a heating furnace 110. Heating the sheet 40 by the heating furnace 110 contributes to the uniform heating of the sheet 40.

[0050] In the heating step, the sheet 40 is heated to a temperature higher than the melting point of the thermoplastic resin. This melts the thermoplastic resin. In the present embodiment, the sheet 40 is heated to 300 °C to 350 °C.

[0051] The metal plates 100 can be made of, for example, a metal material having a relatively low thermal conductivity and a relatively low coefficient of thermal expansion, such as carbon steel.

[0052] The surfaces of the respective metal plates 100 facing the sheet 40 each include a release layer 101 having releasability. The release layer 101 is, for example, a coating containing a fluorine compound.

[0053] Transporting step

[0054] As Figure 5As shown, in the transportation step, with the sheet 40 accommodated in the heat-insulating container 120, the sheet 40 heated in the heating step is transported from the heating furnace 110 to the first mold 130. When the sheet 40 is being transported, the sheet 40 is held between two metal plates 100 and is accommodated in the heat-insulating container 120.

[0055] Pressing step

[0056] As Figure 6 shown, in the pressing step, the sheet 40 is pressed using the first mold 130.

[0057] Now, the structure of the first mold 130 will be described.

[0058] The first mold 130 includes a fixed mold 131 and a movable mold 134 that can move toward and away from the fixed mold 131. The fixed mold 131 and the movable mold 134 respectively include opposing forming surfaces 132, 135, and the sheet 40 is formed on the forming surfaces 132, 135. The fixed mold 131 includes a heater 133 for heating the fixed mold 131. The movable mold 134 includes a heater 136 for heating the movable mold 134. The fixed mold 131 includes a cooling channel 137 through which a refrigerant for cooling the fixed mold 131 flows. The movable mold 134 includes a cooling channel 138 through which a refrigerant for cooling the movable mold 134 flows.

[0059] In the pressing step, an elastic member 140 is disposed between the fixed mold 131 and one of the metal plates 100. Similarly, the elastic member 140 is disposed between the movable mold 134 and the other metal plate 100. The elastic member 140 is an elastically deformable sheet. The elastic member 140 is made of a material containing, for example, glass fiber and fluororubber.

[0060] Before the pressing step starts, the first mold 130 is heated by the heaters 133, 136. That is, in the pressing step, the sheet 40 is pressed using the heated first mold 130. In the pressing step, it is preferable to heat the first mold 130 to, for example, 100°C to 350°C. In the present embodiment, the first mold 130 is heated to a temperature higher than approximately 280°C (which is the melting point of the thermoplastic resin); more specifically, it is heated to 330°C to 350°C.

[0061] In the pressing step, the sheet 40 heated in the heating step and the two metal plates 100 are pressed by the first mold 130 so that the sheet 40 has a predetermined thickness. In the present embodiment, the predetermined thickness refers to the thickness of the partition 30. In the pressing step, the sheet 40 is pressed in a state where each elastic member 140 is located between the corresponding metal plate 100 and the first mold 130 and in a state where each release layer 101 is located between the corresponding metal plate 100 and the sheet 40.

[0062] In the pressing step, the sheet 40 is formed to have a predetermined thickness and then cooled together with the first mold 130. This cooling is performed by passing a refrigerant through the cooling channels 137, 138 of the first mold 130. The first mold 130 is cooled in a state where it is locked.

[0063] The cooling of the sheet 40 reduces the fluidity of the thermoplastic resin. This allows the shape of the sheet 40 that has undergone the pressing step to be easily maintained. That is, the pressing step includes pressing the sheet 40 using the first mold 130 and cooling the pressed sheet 40 until the thermoplastic resin is cured to the extent that the shape of the pressed sheet 40 is maintained.

[0064] First cooling step

[0065] As Figure 7 shown, in the first cooling step, the sheet 40 that has undergone the pressing step is cooled and cured while being held between two first metal members 150 in the thickness direction.

[0066] In the first cooling step, while the sheet 40 is held between two first metal members 150, the sheet 40 is air-cooled at room temperature. Thus, the sheet 40 is cooled to, for example, below 100°C.

[0067] The first metal member 150 is, for example, plate-shaped. Preferably, the first metal member 150 is made of a metal material having a relatively high thermal conductivity and a relatively low coefficient of thermal expansion. The first metal member 150 can be made of, for example, copper or a copper alloy.

[0068] Channel forming step

[0069] As Figure 8 shown, in the channel forming step, the sheet 40 is pressed using the second mold 160.

[0070] Now, the structure of the second mold 160 will be described.

[0071] The second mold 160 includes a fixed mold 161 and a movable mold 164 that can move toward and away from the fixed mold 161. The fixed mold 161 and the movable mold 164 respectively include opposing forming surfaces 162, 165, and the sheet 40 is formed on the forming surfaces 162, 165. The forming surface 162 includes a groove 162a. The forming surface 165 includes a groove 165a. The grooves 162a, 165a are used to transfer the gas passage 31 and the rib 32 to the sheet 40. The fixed mold 161 includes a heater 163 for heating the fixed mold 161. The movable mold 164 includes a heater 166 for heating the movable mold 164. The fixed mold 161 includes a cooling passage 167 through which a refrigerant for cooling the fixed mold 161 flows. The movable mold 164 includes a cooling passage 168 through which a refrigerant for cooling the movable mold 164 flows.

[0072] As Figure 9 shown, in the channel forming step, the second mold 160 is used to press the sheet 40 so that the gas passage 31 and the rib 32 are formed in the sheet 40.

[0073] Before the start of the channel forming step, the second mold 160 is heated by the heaters 163, 166. That is, in the channel forming step, the sheet 40 is pressed using the heated second mold 160. In the channel forming step, it is preferable to heat the second mold 160 to a temperature lower than the melting point of the thermoplastic resin; more specifically, to a temperature of 50°C to 160°C. In the present embodiment, the second mold 160 is heated to approximately 90°C, which is the glass transition temperature of the thermoplastic resin.

[0074] Second cooling step

[0075] As Figure 10 shown, in the second cooling step, the sheet 40 that has undergone the channel forming step is cooled and solidified while being held between two second metal members 170 in the thickness direction.

[0076] The second metal member 170 is, for example, plate-shaped. It is preferable that the second metal member 170 is made of a metal material having a relatively high thermal conductivity and a relatively low coefficient of thermal expansion. The second metal member 170 can be made of, for example, copper or a copper alloy.

[0077] In the second cooling step, while the sheet 40 is held between two second metal members 170, the sheet 40 is air-cooled at room temperature. Therefore, the sheet 40 is cooled to a temperature around room temperature, for example.

[0078] After the second cooling step, a stamping step (not shown) is performed to stamp the sheet 40 using a pressing device. The stamping step includes, for example, the step of arranging through holes in the sheet 40 and the step of trimming the outer peripheral portion of the sheet 40.

[0079] The operation and advantages of the present embodiment will now be described.

[0080] (1) The method of manufacturing the separator 30 includes a heating step, a pressing step, and a channel forming step. The heating step includes heating the sheet 40 to a temperature higher than the melting point of the thermoplastic resin. The sheet 40 is made of a material including a thermoplastic resin and conductive carbon material particles dispersed in the thermoplastic resin. The pressing step includes pressing the sheet 40 heated in the heating step using the first mold 130 to form a sheet having a predetermined thickness. The pressing step also includes cooling the sheet 40 that has been formed to have a predetermined thickness by pressing using the first mold 130 together with the first mold 130. The channel forming step includes pressing the sheet 40 after being pressed by the first mold 130 using the second mold 160 to form gas channels 31 in the sheet 40. That is, the channel forming step includes pressing the sheet 40 cooled in the pressing step using the second mold 160 to form gas channels 31 in the sheet 40. In the sheet 40, the content of the thermoplastic resin is 25% by weight, and the content of the carbon material particles is 75% by weight.

[0081] In this method, the sheet 40 heated to a temperature higher than the melting point of the thermoplastic resin in the heating step is formed to have a predetermined thickness and cooled in the pressing step. Then, in the channel forming step, gas channels 31 are formed in the sheet 40.

[0082] In the sheet 40, the content of the thermoplastic resin is greater than or equal to 20% by weight and less than or equal to 30% by weight, and the content of the carbon material particles is greater than or equal to 70% by weight and less than or equal to 80% by weight. Compared with heating such a sheet 40 to a temperature lower than the melting point, heating the sheet 40 to a temperature higher than the melting point of the thermoplastic resin increases the fluidity of the thermoplastic resin and limits the situation where the sheet 40 loses its shape. This reduces the thickness variation of the sheet 40 that has undergone the pressing step. In the channel forming step, gas channels 31 are formed in the sheet 40 in which the thickness variation has been reduced. Therefore, the thickness variation of the entire separator 30 is reduced.

[0083] In addition, the increase in the fluidity of the thermoplastic resin in the heating step reduces the pressing load of the first mold 130 in the pressing step.

[0084] In addition, heating the sheet 40 to a temperature higher than the melting point of the thermoplastic resin limits the situation where the thermoplastic resin is unevenly distributed in the separator 30. This limits the generation of cracks or pinholes in the separator 30.

[0085] (2) The heating step includes heating the sheet 40 in the heating furnace 110. The method for manufacturing the partition 30 includes a transporting step of transporting the sheet 40 from the heating furnace 110 to the first mold 130 between the heating step and the pressing step.

[0086] For example, when heating the first mold 130 for the heating step, it is necessary to heat the first mold 130 to a temperature higher than the melting point of the thermoplastic resin. In this case, the pressing step requires a long period of time until the cooling of the first mold 130 that has been heated to a temperature higher than the melting point is completed.

[0087] In the above method, the sheet 40 is heated in a device different from the first mold 130 and then transported to the first mold 130. This eliminates the need to heat the first mold 130 to a temperature higher than the melting point. Therefore, the sheet 40 cools for a shorter period of time in the pressing step. Thus, a decrease in the productivity of the partition 30 is restricted.

[0088] (3) The transporting step includes transporting the sheet 40 in a state where the sheet 40 is accommodated in the heat-insulating container 120.

[0089] When the sheet 40 is transported from the heating furnace 110 to the first mold 130, this method restricts the decrease in the temperature of the sheet 40. This restricts the decrease in the fluidity of the thermoplastic resin, thereby reducing the pressing load of the first mold 130 in the pressing step.

[0090] (4) The pressing step includes pressing the sheet 40 using the heated first mold 130.

[0091] When the sheet 40 in the first mold 130 is pressed in the pressing step, this method restricts the decrease in the temperature of the sheet 40. This restricts the decrease in the fluidity of the thermoplastic resin, thereby reducing the pressing load of the first mold 130 in the pressing step.

[0092] (5) The heating step includes heating the two metal plates 100 and the sheet 40 while holding the sheet 40 between the two metal plates 100 in the thickness direction.

[0093] The pressing step includes pressing the sheet 40 between the two metal plates 100.

[0094] In this method, the sheet 40 and the two metal plates 100 are heated in the heating step. Then, in the pressing step, the sheet 40 is pressed between the two metal plates 100. This restricts the decrease in the temperature of the sheet 40 when performing the pressing step. Therefore, the pressing load of the first mold 130 in the pressing step is reduced.

[0095] In addition, in the above method, the sheet 40 is held between two metal plates 100 during the heating step and the pressing step. This restricts the deformation of the sheet 40 during thermal expansion in the heating step and the deformation of the sheet 40 during thermal contraction in the pressing step.

[0096] (6) The pressing step includes pressing the sheet 40 in a state where each elastic member 140 is located between a corresponding one of the two metal plates 100 and the first mold 130.

[0097] In this method, when the elastic member 140 is elastically deformed due to the pressing load of the first mold 130, the pressing load easily acts on the entire sheet 40 through the two metal plates 100 in a uniform manner. This further reduces the thickness variation of the sheet 40 that has undergone the pressing step.

[0098] (7) The pressing step includes pressing the sheet 40 in a state where each mold release layer 101 having mold release properties is located between a corresponding one of the two metal plates 100 and the sheet 40.

[0099] In this method, after the pressing step, each mold release layer 101 is located between the corresponding metal plate 100 and the sheet 40. This improves the mold release property of the metal plate 100 from the sheet 40 and thus contributes to the manufacture of the partition 30.

[0100] (8) The method for manufacturing the partition 30 includes a first cooling step between the pressing step and the channel forming step. In the first cooling step, the sheet 40 is cooled and solidified while being held between two first metal members 150 in the thickness direction of the sheet 40.

[0101] In this method, heat is radiated from the sheet 40 through the two first metal members 150. Therefore, the thermoplastic resin after the pressing step is quickly solidified. This allows the channel forming step to start quickly, thus improving the productivity of the partition 30.

[0102] In addition, in the above method, in the first cooling step, the sheet 40 is held between two first metal members 150. This restricts the deformation of the sheet 40 during thermal contraction.

[0103] (9) The channel forming step includes pressing the sheet 40 with a second mold 160 heated to a temperature lower than the melting point of the thermoplastic resin.

[0104] This method maintains the dimensional accuracy of the sheet 40 having a predetermined thickness and softens the thermoplastic resin. Therefore, in the channel forming step, it is easy to form the gas channels 31 in the sheet 40.

[0105] (10) The method of manufacturing the separator 30 includes a second cooling step after the channel forming step. In the second cooling step, the sheet 40 is cooled and solidified while being held between two second metal members 170 in the thickness direction.

[0106] In this method, heat is radiated from the sheet 40 through the two second metal members 170. This rapidly solidifies the thermoplastic resin after the channel is formed, thereby improving the productivity of the separator 30.

[0107] Further, in the above method, the sheet 40 is held between the two second metal members 170 in the second cooling step. This restricts the deformation of the sheet 40 during thermal shrinkage.

[0108] (11) The method of manufacturing the separator 30 includes forming the sheet 40 by cooling and solidifying a uniform powder composition using a double-belt pressing system after heating and melting the powder composition. The powder composition is obtained using a grinder that grinds thermoplastic resin particles and carbon material particles. The double-belt pressing system includes a pressure heating section and a pressure cooling section.

[0109] In this method, the carbon material particles are coupled to each other using a highly controlled hybrid structure of the sheet 40. This forms a sheet 40 having a high thermal conductivity and a high coefficient of thermal expansion. The method of manufacturing the separator using such a sheet 40 maintains the hybrid structure and reflects the thermal and electrical properties of the separator 30 without degrading the performance.

[0110] Variation

[0111] The present embodiment can be modified as follows. The present embodiment and the following variations can be combined as long as they are technically consistent with each other.

[0112] The second metal member 170 can be made of a metal material other than copper or a copper alloy.

[0113] The second cooling step can be omitted. In this case, the sheet 40 can be cooled and solidified by, for example, cooling the second mold 160.

[0114] In the channel forming step, the second mold 160 can be used to press the sheet 40 without heating the second mold 160.

[0115] The first metal member 150 can be made of a metal material other than copper or a copper alloy.

[0116] The first cooling step can be omitted. In this case, the sheet 40 can be cooled and solidified by, for example, cooling the first mold 130.

[0117] The release layer 101 can be, for example, a release sheet, and each release sheet is disposed separately from the corresponding metal plate 100 between the metal plate 100 and the sheet 40.

[0118] Each release layer 101 can be omitted from the corresponding metal plate 100.

[0119] In the pressing step, the two elastic members 140 can be omitted.

[0120] In the heating step, the two metal plates 100 can be omitted, and only the sheet 40 can be heated. In this case, in the pressing step, the first mold 130 can be used to directly press the sheet 40.

[0121] In the pressing step, the first mold 130 can be used to press the sheet 40 without heating the first mold 130.

[0122] In the transportation step, the heat-insulating container 120 can be omitted.

[0123] In the heating step, the sheet 40 can be heated by using heaters 133, 136 to heat the first mold 130 instead of using the heating furnace 110. In this case, it is preferable to heat the sheet 40 in a state where the first mold 130 is locked.

[0124] Without departing from the spirit and scope of the claims and their equivalents, various changes in form and detail can be made to the above examples. These examples are for illustrative purposes only and not for the purpose of limitation. The description of the features in each example should be considered applicable to similar features or aspects in other examples. Appropriate results can be achieved if the operations are performed in a different order, and / or if the components in the illustrated system, architecture, device, or circuit are combined differently and / or replaced or supplemented by other components or their equivalents. The scope of the present disclosure is not limited by the specific embodiments, but by the claims and their equivalents. All changes within the scope of the claims and their equivalents are included in the present disclosure.

Claims

1. A method for manufacturing a fuel cell separator, the fuel cell separator being made of a material comprising a thermoplastic resin and conductive carbon material particles, the fuel cell separator including gas channels through which reaction gas flows, the method comprises: heating a sheet made of a material comprising a thermoplastic resin and conductive carbon material particles dispersed in the thermoplastic resin; pressing the sheet heated during the heating using a first mold, thereby forming the sheet having a predetermined thickness; cooling together with the first mold the sheet that has been formed to have the predetermined thickness by pressing using the first mold; and pressing the sheet that has undergone the cooling using a second mold, thereby forming the gas channels in the sheet, wherein, in the sheet, the content of the thermoplastic resin is greater than or equal to 20% by weight and less than or equal to 30% by weight, and the content of the carbon material particles is greater than or equal to 70% by weight and less than or equal to 80% by weight, heating the sheet includes heating the sheet to a temperature higher than the melting point of the thermoplastic resin, and pressing the sheet using the second mold includes pressing the sheet using the second mold heated to a temperature lower than the melting point of the thermoplastic resin.

2. The method for manufacturing a fuel cell separator according to claim 1, wherein, heating the sheet includes heating the sheet in a heating furnace, and the method further includes transporting the sheet from the heating furnace to the first mold between heating the sheet and pressing the sheet using the first mold.

3. The method for manufacturing a fuel cell separator according to claim 2, wherein, transporting the sheet includes transporting the sheet in a state where the sheet is accommodated in a heat-insulating container.

4. The method for manufacturing a fuel cell separator according to claim 1, wherein, pressing the sheet using the first mold includes pressing the sheet using the heated first mold.

5. The method for manufacturing a fuel cell separator according to claim 1, wherein, heating the sheet includes heating the two metal plates and the sheet in a state where the sheet is held between the two metal plates in the thickness direction, and, pressing the sheet using the first mold includes pressing the sheet between the two metal plates.

6. The method for manufacturing a fuel cell separator according to claim 5, wherein, pressing the sheet using the first mold includes pressing the sheet in a state where an elastic member is located between the first mold and each of the two metal plates.

7. The method for manufacturing a fuel cell separator according to claim 5, wherein, pressing the sheet using the first mold includes pressing the sheet in a state where a release layer is located between the sheet and each of the two metal plates, wherein the release layer has releasability.

8. The method for manufacturing a fuel cell separator according to claim 1, further comprises: Between cooling the sheet together with the first mold and pressing the sheet using the second mold, the sheet is cooled and solidified while being held between two metal members in the thickness direction of the sheet.

9. The method for manufacturing a fuel cell separator according to claim 1, further comprising: After pressing the sheet using the second mold, the sheet is cooled and solidified while being held between two metal members in the thickness direction of the sheet.

10. The method for manufacturing a fuel cell separator according to any one of claims 1 to 9, further comprising: Forming the sheet by cooling and solidifying a uniform powder composition after heating and melting the powder composition using a double-belt pressing system, wherein the powder composition is obtained using a grinder that grinds particles of the thermoplastic resin and particles of the carbon material, and the double-belt pressing system includes a pressure heating section and a pressure cooling section.

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