JP2004134090A - Manufacturing method and manufacturing device of stainless steel separator for solid polymer fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method and a manufacturing device of a separator applicable to a low-cost and high-durability solid polymer fuel cell free from warping or rippling of the separator as a whole. <P>SOLUTION: In the manufacturing method of the stainless steel separator for the solid polymer fuel cell having a flat part at a periphery as well as a projection part and a recess part to become a gas flow channel at the part except the periphery, a material part fitted with the projection part and the recess part to become the gas flow channel is heated to 60°C to 150°C, a part or whole part of the material part to become the flat part at the periphery is cooled to 0°C to 20°C to give the material a temperature gradient, and is later overhung molded in a repeated cross section shape of a projection part and a recess part. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing a stainless steel separator used in a polymer electrolyte fuel cell used for an automobile driven by electric power, a small-scale power generation system, and the like.
[0002]
[Prior art]
With increasing awareness of environmental conservation, the transition from the current internal combustion engine using fossil fuels to electric drive type vehicles using hydrogen-based polymer electrolyte fuel cells and distributed cogeneration systems is being considered worldwide. I have. In order to make these new technologies widely available to the general public, it is necessary to promote the development of technologies related to cost reduction and high reliability, including the fuel supply system.
In recent years, the development of fuel cells for electric vehicles has begun to progress rapidly with the success of the development of solid polymer materials.
[0003]
Unlike polymer electrolyte fuel cells, which are conventional alkaline fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, and solid electrolyte fuel cells, solid polymer fuel cells use a hydrogen ion selective permeation type organic membrane as the electrolyte. A fuel cell characterized by the fact that, in addition to pure hydrogen, hydrogen gas obtained by reforming alcohols is used as fuel, and power is extracted by electrochemically controlling the reaction with oxygen in the air. System. Solid polymer membranes function well even when they are thin, and since the electrolyte is fixed in the membrane, they function as electrolytes when the dew point in the battery is controlled, so fluidity such as aqueous electrolytes and molten salt electrolytes Another feature is that the battery itself can be designed to be compact and simple without the need to use a medium having a certain size.
The polymer electrolyte fuel cell is a single cell with a sandwich structure consisting of a separator having a hydrogen flow path, a fuel electrode, a solid polymer membrane, an air (oxygen) electrode, and a separator having an air (oxygen) flow path. A stack in which the single cells are stacked is used. Therefore, both sides of the separator have independent flow paths, one side is a hydrogen path, and the other side is a flow path of air and generated water.
[0004]
As a constituent material of the polymer electrolyte fuel cell that operates in a region below the boiling point of the cooling aqueous solution, the temperature is not so high, and it is possible to sufficiently exhibit corrosion resistance and durability under the environment, Furthermore, carbon-based materials have been used by machining to form an arbitrary flow path shape, such as by cutting, but stainless steel and titanium have been used to reduce costs and downsize, that is, to make separators thinner. Technological development for the application of is progressing.
[0005]
Conventionally, as stainless steels for fuel cells, Patent Document 1 (Japanese Patent Application Laid-Open No. Hei 4-247852), Patent Document 2 (Japanese Patent Application Laid-Open No. Hei 4-358844), Patent Document 3 (Japanese Patent Application Laid-Open No. Hei 7-188870), Patent As disclosed in Document 4 (JP-A-8-165546), Patent Document 5 (JP-A-8-225892), and Patent Document 6 (JP-A-8-31620), high corrosion resistance is required. There are stainless steels for fuel cells that operate in a molten carbonate environment.
Further, as disclosed in Patent Document 7 (Japanese Patent Application Laid-Open No. 6-264193), Patent Document 8 (Japanese Patent Application Laid-Open No. 6-293914), and Patent Document 9 (Japanese Patent Application Laid-Open No. 9-67672), The invention of a solid oxide fuel cell material operating at a high temperature of one hundred degrees has been made.
[0006]
Further, Patent Document 10 (Japanese Patent Application Laid-Open No. 10-228914) discloses that a stainless steel (SUS304) is stretch-formed (also referred to as press-formed) for the purpose of obtaining a fuel cell separator having low contact resistance with an electrode of a unit cell. ) To form a bulged portion formed of a large number of irregularities on the inner peripheral portion, and form a gold plating layer having a thickness of 0.01 to 0.02 μm on the bulging tip side end surface of the bulged formed portion. A fuel cell separator is disclosed, wherein the fuel cell separator is interposed between the stacked unit cells when forming the fuel cell, and the electrodes of the unit cell and the bulging molded portion are used. There is disclosed a technique in which a gold plating layer formed on an end surface of a bulging tip side is disposed so as to abut, and a reaction gas passage is defined between a fuel cell separator and an electrode. In addition, Patent Document 11 (Japanese Patent Application Laid-Open No. 5-29909) discloses a press-processed corrugated bipolar plate having a wavy shape for processing at low cost. Regarding molding using a roll, Patent Document 12 (Japanese Patent Application Laid-Open No. 2000-202532) discloses a manufacturing method in which a flat plate is sandwiched between dies and the dies are compressed by rolling rolls.
[0007]
As for warm working, a large member is soaked by a mold heating heater and a material heating heater in Patent Document 13 (Japanese Patent Application Laid-Open No. 6-234025), and the hot working blow molding and vacuum forming methods are used. A molding method for extending a large-sized member with a smaller deformation resistance is disclosed. Patent Document 14 (Japanese Patent Application Laid-Open No. 6-304672) discloses a high-temperature bulge in which a plate material is heated using a heated pressurized medium. A forming method is disclosed in which a large deformation amount of a plate material is obtained by a forming method and a pressing force required for forming is reduced. Further, in Patent Document 15 (Japanese Patent Application Laid-Open No. 7-47431), using a press-molding die apparatus provided with a high-pressure high-temperature gas outlet and a heating element in a die punch, the proof stress during processing is reduced to improve the formability. A warm forming method is disclosed which improves and reduces springback.
[0008]
However, when a polymer electrolyte fuel cell was actually manufactured based on these technologies, the following technical problems were found.
a) The separator is assumed to have a shape in which a bulge-formed portion composed of a large number of irregularities is formed on the inner peripheral portion by press molding. Ductile cracking occurs in the bulging formed portion, and particularly, corner portions of the uneven portion are apt to break because bending distortion is increased. Further, since stainless steel having an increased alloy composition for improving long-term reliability has lower workability than SUS304, it is difficult to press-mold into this shape.
b) In the method of forming a repetitive shape of irregularities by press molding, when the separator becomes large, the press load increases and large-scale equipment is required.
c) In the manufacturing method of compressing the mold with a roll, the productivity is low in opening and closing the mold, material handling, and the like, and the rigidity of the mold makes it difficult to accurately apply a rolling load.
d) In bulge molding or blow molding, it is suitable for stretch forming in one direction. However, in stretch forming of a separator having a repeating shape of irregularities, it becomes difficult to stretch and form an ultrathin plate uniformly in both directions.
e) When the material of the flat portion around the convex portion and the concave portion serving as the gas flow path is formed by processing, a flat portion around the separator has a wavy shape, and when the fuel cell stack is constructed as shown in FIG. Gas performance and water leakage occur.
[0009]
[Patent Document 1] JP-A-4-247852 [Patent Document 2] JP-A-4-358844 [Patent Document 3] JP-A-7-188870 [Patent Document 4] JP-A-8-165546 [Patent] Reference 5 Japanese Patent Application Laid-Open No. 8-225892 [Patent Document 6] Japanese Patent Application Laid-Open No. 8-31620 [Patent Document 7] Japanese Patent Application Laid-Open No. 6-264193 [Patent Document 8] Japanese Patent Application Laid-Open No. 6-293940 [Patent Document 9] Japanese Patent Application Laid-Open No. 9-67672 [Patent Document 10] Japanese Patent Application Laid-Open No. 10-228914 [Patent Document 11] Japanese Patent Application Laid-Open No. 5-29909 [Patent Document 12] Japanese Patent Application Laid-Open No. 2000-202532 [Patent Document 13] [Patent Document 14] Japanese Patent Application Laid-Open No. 6-304672 [Patent Document 15] Japanese Patent Application Laid-Open No. 7-47431
[Problems to be solved by the invention]
In view of the above problems, the present invention can be applied to a low-cost, high-durability type polymer electrolyte fuel cell. It is an object of the present invention to provide a method and apparatus for manufacturing a separator in which uneven portions are uniformly formed and a peripheral flat portion has a small wavy shape.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, based on the operation principle of the polymer electrolyte fuel cell, a detailed study of the material behavior at the time of molding processing has resulted in the completion of the present invention. It is on the street.
(1) In a method of manufacturing a stainless steel separator for a polymer electrolyte fuel cell having a flat portion in the periphery and a convex portion and a concave portion serving as a gas flow path in a portion excluding the periphery, the material is heated to 60 ° C to 150 ° C. And thereafter, forming a stainless steel separator for a polymer electrolyte fuel cell by stretch forming into a repetitive cross-sectional shape of a convex portion and a concave portion.
(2) In the method for manufacturing a stainless steel separator for a polymer electrolyte fuel cell, which has a flat portion in the periphery and a portion excluding the periphery has a convex portion and a concave portion serving as a gas channel, the convex portion and the concave portion serving as a gas channel. Is heated to 60 ° C. to 150 ° C., and a part or the whole of the material portion to be a flat portion around the periphery is cooled so as to be 40 to 150 ° C. lower than the heating temperature, so that a temperature gradient is applied to the material. A method for manufacturing a separator for a polymer electrolyte fuel cell, comprising: forming a protrusion and a recess in a repetitive cross section.
(3) The method for producing a stainless steel separator for a polymer electrolyte fuel cell according to the above (1), wherein a part or all of a material portion to be a peripheral flat portion is cooled to 0 ° C to 20 ° C.
(4) A solid polymer having a material heating device at the front stage and a pair of upper and lower pressing rolls on the surface of which the surface has been subjected to uneven processing similar to the repetitive cross-sectional shape of the projections and recesses of the separator at the latter stage. For manufacturing stainless steel separators for portable fuel cells.
(5) It has a material heating device and a material cooling device at the front stage, and has a pair of upper and lower pressing rolls on the surface of which the surface has been subjected to uneven processing similar to the repetitive cross-sectional shape of the projections and recesses of the separator at the latter stage. For manufacturing stainless steel separators for polymer electrolyte fuel cells.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, details of the present invention will be described.
As described above, in the process of forming the separator having the repetitive cross-sectional shape of the concave-convex portion, a problem may occur in which the peripheral flat portion has a wavy shape.
The present inventors have focused on warm working, which has conventionally been used as a countermeasure for reducing the deformation resistance of the work material and reducing the springback by reducing the proof stress, and designed roll dies for various shapes. As a result of forming a prototype and providing a function of warmly heating the material in the preceding stage of the roll mold and performing forming processing, it has been found that the entire separator can be reduced in waving, cracking, and breaking. FIG. 1 shows an example of a sectional view of the separator 1 according to the present invention. Stainless steel has temperature dependency of flow stress, especially austenitic stainless steel tends to cause work hardening due to martensite phase transformation at room temperature, and improves fluidity by suppressing phase transformation by warm working. be able to. In addition, with respect to ferritic stainless steel, since slip deformation due to the movement of dislocations, which is a main cause of work hardening, also has temperature dependence, the fluidity of warm working is improved. Therefore, since the deformation resistance is reduced and the elongation of the material is improved due to the improvement of the fluidity due to the warm working, it is possible to stably form the repetitive cross-sectional shape of the protrusions and the recesses of the separator without cracking or breaking. it can. If the temperature of the warm working is too high, the breaking force is reduced due to softening, and if the temperature is too low, the fluidity is not improved.
[0013]
The present inventors further locally warm only the portions to be processed into the convex portions and concave portions serving as gas flow paths, and locally cool part or all of the surrounding flat portions 20 to form irregularities. It has been found that by lowering the heating temperature of the flat part by 40 to 150 ° C., the fluidity is reduced so that the material of the flat part is not drawn into the center, and the wavy shape of the separator can be reduced. If the temperature of the flat portion is not lower than the heating temperature of the uneven portion by 40 ° C. or more, the reduction of the wavy shape of the separator is not sufficient, and if the temperature is lower than the heating temperature of the uneven portion by more than 150 ° C., it is difficult to process and brittle fracture easily occurs. Therefore, it is preferable to cool part or all of the flat portion so as to be in the above-mentioned temperature range. It is preferable that the entire area for cooling the flat portion is set, but the above effect can be obtained by cooling a part of the flat area. In the case where a part is cooled, it is preferable to cool a surface parallel to the longitudinal direction of the groove shape of the concavo-convex portion that is more easily drawn into the central portion.
If the temperature of the surrounding flat portion is too low, brittle fracture occurs, so it is more desirable to cool to 0 ° C to 20 ° C.
As a material of the separator, a graphite plate, a metal plate, or the like can be used from the viewpoints of electron conductivity, corrosion resistance, and airtightness.
[0014]
Next, the manufacturing apparatus of the present invention will be described.
FIG. 3 shows an example of the cross-sectional shape on one side from the center axis of the upper roll 31a and the lower roll 31b, and has a roll flat portion 41 for rolling a flat flat portion. The roll gap h of the roll flat portion 41 is set to be smaller than the original thickness of the plate material to be processed so that rolling can be performed, and the roll gap h is 90.0 to 99.8 of the thickness of the plate material. % Is desirable. The roll gap h1 of the uneven portion at the center portion is 70 to 90 times the original thickness of the plate material to be processed in order to obtain a good separator shape having a flat top and low contact resistance (large contact area). % Is desirable. On the other hand, if the width B of the roll flat portion 41 is excessively large, the roll body length becomes longer, the amount of roll deflection increases, and the forming process becomes uneven. The width B of the roll flat portion 41 is preferably 5 to 20% of the width B1 of the roll central uneven portion 42.
[0015]
In FIG. 4, the separator is continuously rotated by a pair of molding press rolls 31 a and 31 b having a surface with irregularities, and rotating while transferring the pattern of the irregularities 35 on the surface to the plate material. An example of a rolling roll in a manufacturing apparatus to be manufactured in a typical manner is shown. Immediately before the press-down rolls 31a, 31b, side guides 32a, 32b each having a groove having a thickness of about the plate are provided at the center of the vertical roll in order to prevent meandering of the plate material.
Alternatively, a method may be used in which the sprocket holes 33 are punched at both ends of the plate material at a fixed pitch in advance, and the sprocket wheels 34a and 34b position the sprocket holes 33. FIG. 5 shows an example of a positioning mechanism using a sprocket wheel. The arrows in the figure indicate the direction of transport of the plate material. The separator is continuously formed by rotating the stainless steel plate material by a pair of shaping pressing rolls 31a and 31b whose surfaces have been subjected to unevenness while transferring the unevenness pattern 3 on the surface to the thin plate. Can be manufactured.
[0016]
FIG. 6 is a schematic diagram illustrating an example of the surface shape of the final forming press roll. The irregularities of the pressing rolls 31a and 31b for forming have a structure in which convex portions and concave portions are repeated along the axial direction of the pressing rolls.
[0017]
FIG. 7 is a schematic diagram of a manufacturing apparatus in which a heating-roll-type material heating device 51 is combined with press-down rolls 31a and 31b. As the heating roll 51, an electric heating type in which a sheathed heater is incorporated in the roll, a heating medium circulation type in which a heating medium such as oil or hot water is circulated, a steam heating type, or the like is used. The material of the contact surface of the heating roll 51 is desirably a copper alloy of a good heat conductor. The set temperature of the heating roll 51 is determined in consideration of the processing temperature of the plate material, the ambient temperature, the distance L between the heating roll 51 and the forming rolls 31a and 31b, the passing speed, and the like.
In order to heat all of the material, the width of the heating roll 51 may be set to be equal to or greater than the width of the material, and if only the uneven portion of the separator is heated and part or all of the flat portion is cooled, heating may be performed. The heating means may be provided only for the width of the material corresponding to the roll 51, and the cooling means may be provided as needed so that a predetermined temperature difference is provided at a portion corresponding to the flat portion.
Further, the above-mentioned heating type warm heating device may be incorporated into the pressing roll for molding to carry out molding.
[0018]
FIG. 8 is a schematic diagram of a manufacturing apparatus in which a hot water shower-type material heating device 52 is combined with a pressing roll 31a, 31b.
FIG. 9 is a schematic diagram of a manufacturing apparatus in which a heater-type material heating device 53 and a pressing roll for forming are combined. The heater 53 is locally heated using a lamp heater, a ceramic heater, or the like.
FIG. 10 is a schematic diagram of a manufacturing apparatus in which a heating roll type material heating device 51 and a material cooling device 54 are combined with the pressing rolls 31a and 31b for molding. In FIG. 10, the heating roll 51 is used as the material heating device, but a hot water shower type, a heater type, or a method in which a heating device is incorporated in a pressing roll for molding may be used. The set temperatures of the heating roll 51 and the cooling roll 54 are as follows: the processing temperature of the sheet material, the ambient temperature, the distance L1 between the heating roll 51 and the cooling roll 54, the distance L2 between the cooling roll 54 and the forming press rolls 31a and 31b, Determined in consideration of speed, etc. As a cooling method of the cooling roll, a method using a refrigerant such as gas or water is used.
[0019]
FIG. 11 is a schematic view of a local heating roll, and FIG. 12 is a schematic view of a local cooling roll. The material is locally heated and removed by the heat transfer surface portions 55 and 56, and the other portions are at room temperature. It is preferable that the heat transfer surface portion is formed of a copper alloy of a good heat conductor or the like, and a heat insulating portion 57 is provided at a boundary of the heat transfer surface portion.
[0020]
(Example)
An uneven pattern as shown in FIG. 13 was formed by machining on a pair of forming rolls having a diameter of 200 mm and a length of 300 mm. The cross-sectional shape is as shown in FIG. 4, and the uneven portion has a width of 250 mm and a length (arc length) of 150 mm. On the other hand, the convex portion of the pressing roll for molding has a convex shape with a radius of curvature of 0.5 mm, the bottom portion is a smooth surface with a width of 0.5 mm, and the groove depth is 0.5 mm. The roll gap h is 0.095 mm, and the roll flat portion B is 30 mm.
Using a device as shown in FIGS. 4 and 10, a plate is continuously supplied from a coil of austenitic stainless steel SUS316 having a plate width of 290 mm and a plate thickness of 0.1 mm, and the uneven portions of the upper and lower pressing rolls 31 a and 31 b for forming. The processing was performed with the roll gap h1 of 0.08 mm. The material of the rolling roll was SKD11. The material of the heat transfer surfaces 55 and 56 of the heating roll 51 and the cooling roll 54 is brass C2600. The heating roll 51 has a diameter of 100 mm, a length of 250 mm, the heat transfer portion width W1 is 200 mm, and the cooling roll 54 has a diameter of 100 mm. , Length 100 mm, and heat transfer part width W2 were 25 mm. The interval L1 between the heating roll 51 and the cooling roll 54 was 50 mm, and the interval L2 between the cooling roll 54 and the vertical pressing rolls 31a and 31b was 200 mm. The passing speed was set to 400 mm / sec, the temperature of the heating roll was set to 110 ° C., the temperature of the cooling roll was set to 2 ° C., and the portions other than heating or cooling were set to room temperature. The temperature of the sheet material during the forming process was about 90 ° C. in the central part and about 10 ° C. in the peripheral flat part. The vertical rolling roll was provided with a rotation synchronizing means by a servomotor, and a ball bearing of high accuracy grade was provided on the rolling roll bearing so as not to generate a relative displacement in the roll axis direction.
[0021]
The plate formed without irregularities cracking or breaking, after drilling for introduction and discharge of fuel gas and cooling water, etc., cut at predetermined length, the unit cell separator It could be manufactured. Further, even after cutting, the wavy shape which was initially several mm was reduced to several μm or less by using the present apparatus, and a good shape was obtained. Thereafter, after performing appropriate surface treatments and the like, the fuel cell stack was constructed and performance tests were performed.No gas leakage or water leakage occurred, and the fuel cell was favorably used as a fuel cell using the separator according to the manufacturing method of the present invention. It was confirmed to work.
The forming process by the method of the present invention has a corrugation generation rate of 1/1000 or less, when compared to a case where a similar uneven shape having a width of 250 mm x a length of 150 mm is performed by a normal press working without using a heating and cooling roll. The conventional single-stage press required a load of about 5,000 tons, whereas the present invention requires about 40 tons, and can be manufactured with an extremely inexpensive apparatus.
[0022]
【The invention's effect】
INDUSTRIAL APPLICABILITY The present invention facilitates highly accurate press forming of a stainless steel separator for a polymer electrolyte fuel cell, and is extremely effective as a technique for realizing a low-cost polymer electrolyte fuel cell.
[Brief description of the drawings]
FIG. 1 is an example of a cross-sectional view of a separator manufactured according to the present invention.
FIG. 2 is a schematic view showing an example of constructing a polymer electrolyte fuel cell stack using a separator manufactured according to the present invention.
FIG. 3 is a schematic view showing an example of a cross-sectional shape of a pressing roll in the present invention.
FIG. 4 is a schematic view showing an example of a pressing roll in the separator manufacturing apparatus according to the present invention.
FIG. 5 is a schematic view showing an example of a material positioning mechanism using a sprocket wheel.
FIG. 6 is a schematic view showing an example of the surface shape of a pressing roll in the separator manufacturing apparatus according to the present invention.
FIG. 7 is a schematic view of a manufacturing apparatus in which a heating-roll-type material heating apparatus and a forming-down roll are combined.
FIG. 8 is a schematic diagram of a manufacturing apparatus in which a hot water shower-type material heating apparatus and a pressing roll for forming are combined.
FIG. 9 is a schematic diagram of a manufacturing apparatus in which a heater-type material heating apparatus and a forming draft roll are combined.
FIG. 10 is a schematic diagram of a manufacturing apparatus in which a heating roll type material heating device and a material cooling device are combined with a pressing roll for forming.
FIG. 11 is a schematic view of a local heating roll.
FIG. 12 is a schematic view of a local cooling roll.
FIG. 13 is a schematic view showing another example of the surface shape of a pressing roll for molding in the present invention.
[Explanation of symbols]
1: Separator 7: concave portion (fuel gas flow channel) 8: convex portion (oxygen (air) flow channel)
9: flat part around the separator 10: seal plate 11: electrode (carbon fiber current collector) 12: solid polymer film 20: flat parts 31a, 31b: pressing rolls 32a, 32b for molding: side guide 33: sprocket hole 34a, 34b: sprocket wheel 35: uneven portion 41: roll flat portion 42: roll center uneven portion 43: uneven portion 51: heating roll 52: hot water shower 53: heater 54: cooling roll 55: heat transfer surface 56 of heating roll: cooling Roll heat transfer surface 57: heat insulation

Claims (5)

In the method for manufacturing a stainless steel separator for a polymer electrolyte fuel cell having a flat portion in the periphery and a portion excluding the periphery having a convex portion and a concave portion serving as a gas flow path, the material is heated to 60 ° C. to 150 ° C. A method for producing a stainless steel separator for a polymer electrolyte fuel cell, wherein the stainless steel separator is stretched and formed into a repetitive cross-sectional shape of a projection and a depression. In the method for manufacturing a stainless steel separator for a polymer electrolyte fuel cell having a flat portion in the periphery and a portion excluding the periphery having a convex portion and a concave portion serving as a gas flow channel, a convex portion and a concave portion serving as a gas flow channel are provided. The material part to be heated is heated to 60 ° C. to 150 ° C., and a part or all of the material part to be a flat part in the periphery is cooled so as to be 40 to 150 ° C. lower than the heating temperature, thereby giving a temperature gradient to the material, Thereafter, a method for producing a separator for a polymer electrolyte fuel cell, comprising forming a projection into a repetitive cross-sectional shape of a convex portion and a concave portion. 3. The method for producing a stainless steel separator for a polymer electrolyte fuel cell according to claim 2, wherein a part or all of a material portion to be a peripheral flat portion is cooled to 0C to 20C. A polymer electrolyte fuel cell having a material heating device in the first stage, and a pair of upper and lower pressing rolls on the surface of which the surface is subjected to uneven processing similar to the repetitive cross-sectional shape of the convex and concave portions of the separator in the subsequent stage. For manufacturing stainless steel separator. A solid height characterized by having a material heating device and a material cooling device in the first stage, and a pair of upper and lower pressing rolls on the surface of which the surface has been subjected to unevenness processing similar to the repeated cross-sectional shape of the convex and concave portions of the separator in the subsequent stage. Equipment for manufacturing stainless steel separators for molecular fuel cells.

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