JP2007026812A - Manufacturing method of gas flow passage forming material, gas flow passage forming material of metal separator for fuel cell, and through-hole forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a passage forming material for a fuel cell separator which ensures good gas supply and sufficient mechanical strength. <P>SOLUTION: A primary opening area 11a where many through-holes are formed at a primary numerical aperture with high aperture ratio, and a secondary opening area 11b where many through-holes are formed at a secondary numerical aperture with an aperture ratio lower than the primary one are formed alternately in layers on a thin material (opening area forming process). Then, on the material where the through-holes are formed in such a way, a striped concave portion and striped convex portion are formed as gas flow passages. At this time, the striped concave portion and striped convex portion are formed so that the primary opening area 11a where the through-holes are formed at a primary numerical aperture may be positioned at the groove bottom on the striped concave portion (concave and convex forming process). Such a process manufactures the passage forming materials. In assembling a single cell of fuel cell, the groove bottom is brought into contact with the MEA. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a gas flow path for a fuel cell metal separator in which a plurality of streak-like recesses and streak-like projections are formed on a thin-walled material, particularly a thin-walled material having a large number of through holes formed in a mesh shape. The present invention relates to a forming member manufacturing method, a gas flow path forming member of a fuel cell metal separator manufactured by the manufacturing method, and a through hole forming apparatus for forming a through hole in a material used for the gas flow path forming member.

  Conventionally, for example, a structure of a fuel cell as shown in Patent Document 1 below is known. The metal separator in the fuel cell structure includes a current collector that supports the anode electrode or the cathode electrode, and a gas flow path forming member that forms a gas flow path for supplying fuel gas or oxidant gas to each electrode. It has a structure to provide. In addition, a large number of through-holes are formed between the current collector of the metal separator and the electrode, and an expanded metal having a large number of uneven shapes is provided on the surface thereof. Then, by appropriately adjusting the thickness (unevenness dimension) of the expanded metal, it is possible to ensure good contact between the anode electrode or cathode electrode of the fuel cell and the expanded metal, and to reduce the loss of generated electricity. It is like that.

  Further, conventionally, for example, a fuel cell in which a grooved plate material as shown in Patent Document 2 below is adopted as a gas flow path forming member of a metal separator is also known. The grooved plate material is manufactured by preforming a corrugated shape with respect to a flat clad material having a thin layer formed on the surface thereof, and then finally forming a desired groove shape. Then, by adopting the manufactured grooved plate material as a metal separator, the formed groove suitably separates fuel gas or air, and the separated fuel gas or air is separated from the anode electrode or cathode electrode of the fuel cell. It is supposed to be conductive.

Furthermore, conventionally, for example, a fuel cell separator as shown in Patent Document 3 below is known. The separator of the fuel cell has a flat plate-like first member (carbon) and a plurality of projecting pieces stacked on the first member, elastically contacting the electrode layer of the fuel cell and forming a gas flow path. It is comprised from the 2nd member (metal plate). The gas flow path formed by the plurality of projecting pieces of the second member is a space that exists around or inside the projecting piece, and the inflowing gas communicates in three dimensions in all directions. Yes. For this reason, the reaction efficiency of the gas flowing through the gas flow path is increased, the gas diffusibility with respect to the electrode layer is made more uniform, and the power generation efficiency of the fuel cell is improved.
JP-A-8-138701 JP 2003-249238 A JP 2002-184422 A

  Generally, in order to improve the power generation efficiency of a fuel cell, it is important to improve the electrode reaction and current collection efficiency. For this reason, the metal separator employed in the fuel cell efficiently collects the fuel gas and oxidant gas introduced into the fuel cell to the electrode layer and efficiently collects electricity generated by the electrode reaction. Function is required.

  By the way, in the structure of the conventional fuel cell shown by the said patent document 1, since the contact with an expanded metal and an electrode is ensured favorably, the function which collects generated electricity efficiently is satisfied. However, fuel gas or oxidant gas is supplied to the electrode by a gas-impermeable current collector support. For this reason, sufficient fuel gas or oxidant gas cannot be supplied to each electrode. In other words, gas diffusibility becomes non-uniform, and the function of supplying gas efficiently may not be satisfied.

  Further, in the conventional fuel cell shown in Patent Document 2, a groove can be accurately formed in the clad material, and sufficient contact with each electrode is ensured. For this reason, the function of efficiently collecting the generated electricity is satisfactory. However, as in the fuel cell of Patent Document 1, fuel gas or oxidant gas is supplied to the electrode through a groove formed in the gas-impermeable cladding material. For this reason, the gas diffusibility with respect to each electrode becomes non-uniform, and the function of supplying gas efficiently may not be satisfied.

  Further, in the conventional fuel cell separator disclosed in Patent Document 3, the function of supplying gas by ensuring good gas diffusibility is satisfied, but the portion in contact with the electrode layer is the protrusion piece. Since it is in the vicinity of the top surface, the current collecting resistance may increase and the current collecting efficiency may decrease. In addition, when the projecting piece is formed on a thin metal plate, the power generation efficiency required for the fuel cell may not be ensured due to molding restrictions, for example, the height restriction of the projectable projecting piece.

  In order to satisfy such a demand for a fuel cell, for example, if a metal separator flow path forming member is formed by forming a large number of grooves as flow paths in an expanded metal having a large number of through holes in a mesh shape, Gas diffusibility with respect to the electrode layer can be ensured satisfactorily by allowing the gas to pass through the expanded metal through-hole while ensuring good contact with the electrode. Therefore, it is considered that the function required for the fuel cell, that is, the function of efficiently supplying the gas and the function of efficiently collecting the generated electricity can be achieved. However, since expanded metal has a large number of through holes formed in a mesh, it is difficult to ensure mechanical strength. For example, expanded metal can be deformed by a fastening force applied during assembly of a fuel cell. There is sex. For this reason, the function of supplying gas efficiently may be impaired. Further, if the opening area of the through hole is made small in order to ensure the mechanical strength, gas diffusibility from the through hole is impaired, and there is a problem that efficient gas supply is hindered.

  The present invention has been made to solve the above-described problems, and its object is to manufacture a gas flow path forming member for a fuel cell metal separator that supplies gas satisfactorily and has sufficient mechanical strength. PROBLEM TO BE SOLVED: To provide a method, a flow path forming member of a fuel cell metal separator formed in such a manner, and a through hole forming apparatus for forming a through hole in a material used for such a fuel cell metal separator It is in.

  In order to achieve the above object, the present invention is characterized in that a gas flow path in which a gas flow path for supplying a fuel gas and an oxidant gas to an electrode layer constituting an electrode structure of a fuel cell is formed. A manufacturing method of a forming member, wherein a first material is formed by forming a plurality of through holes in a thin material with a first aperture ratio, and a plurality of through holes with a second aperture ratio lower than the first aperture ratio. The opening forming step of alternately forming the second openings formed with the holes in layers, and the thin material so that the first opening formed by the opening forming step is the groove bottom of the recess. An object of the present invention is to provide a manufacturing method including a concave-convex forming step of alternately forming a plurality of streaky concave portions and streaky convex portions as gas flow paths. In this case, the thin-walled material is, for example, a lath cut metal in which a large number of through holes are formed in a mesh shape by shear bending with respect to a flat metal thin plate, or such a lath cut metal is formed into a substantially flat plate shape by rolling. It is good that it is a molded expanded metal.

  Another feature of the present invention is that the gas flow of the fuel cell metal separator that forms gas flow paths for supplying the fuel gas and the oxidant gas to the electrode layers constituting the electrode structure of the fuel cell, respectively. In the path forming member, the gas flow path forming member includes a first opening in which a plurality of through holes are formed in a thin material at a first opening ratio, and a second opening ratio lower than the first opening ratio. The second openings in which a large number of through holes are formed are alternately formed in layers, and the thin material is used as the gas flow path so that the formed first openings become the groove bottoms of the recesses. It is to be formed by alternately forming a plurality of streaky concave portions and streaky convex portions. In this case, the thin-walled material is, for example, a lath cut metal in which a large number of through holes are formed in a mesh shape by shear bending with respect to a flat metal thin plate, or such a lath cut metal is formed into a substantially flat plate shape by rolling. It is good that it is a molded expanded metal.

  According to the present invention, a large number of through holes are first formed in a thin material. In this case, a first opening portion in which a large number of through holes are formed with a first opening ratio with a high opening ratio, and a plurality of through holes with a second opening ratio that is lower than the first opening ratio. Through holes are formed in the material so that the formed second openings are alternately formed in layers (opening forming step). And the streak-like recessed part and streak-like convex part as a gas flow path are formed in the raw material in which the through-hole was formed in this way. At this time, the streak-like concave part and the streak-like convex part are formed so that the first opening part in which the through-hole is formed with the first aperture ratio is located at the groove bottom part of the streak-like concave part (unevenness forming step). The gas flow path forming member of the fuel cell metal separator manufactured through the opening forming step and the concave-convex forming step includes a streak-like recess and a streak-like convex part that form the gas flow path, and a through-hole of the streak-like recess. The aperture ratio of the hole is higher than the aperture ratio of the through hole in the other part. That is, the opening area of the groove bottom portion of the streak-shaped recess is larger than the opening area of other portions. Therefore, the gas supply from the gas flow path to the electrode structure can be improved by bringing the groove bottom portion into contact with the electrode structure. Further, since the opening ratio of the portion other than the groove bottom of the streak-like recess is low and the opening area is small, the mechanical strength does not decrease with the increase in the opening area. Therefore, it is possible to manufacture or mold a fuel cell metal separator that has both ensured mechanical strength and improved gas diffusibility.

  Here, in the present invention, “lass-cut metal” means that a thin mesh-shaped through-hole is formed by sequentially processing staggered cuts on a flat thin metal plate and pressing and bending the cut cuts. It is formed. In addition, “expanded metal” is a thin metal plate that is formed in a zigzag pattern on a flat thin metal plate, and a small through-hole with a mesh shape is formed by pressing and bending the processed cut. It is processed into a substantially flat plate shape. Since the expanded metal is formed in a substantially flat plate shape, for example, it is not necessary to provide a process for removing unnecessary bending or unevenness in the product after final forming, and the manufacturing cost can be reduced.

  In the present invention, the “aperture ratio” refers to the ratio of the opening area of the through holes formed per unit area of the material. Therefore, in order to make the opening ratios different between the first opening and the second opening, the through holes are formed in the same shape, and the formation interval of the through holes is made different between the first opening and the second opening. Both portions can also be formed, and the formation interval of the through holes is the same, and both portions can be formed so that the hole areas themselves are different by making the shape of the through holes similar to each other. it can.

  Further, in the present invention, the “striated recess” refers to a portion formed in a groove shape in the material of the flow path forming member, and is formed on the groove bottom portion that is linearly recessed from the material plane and on both side ends of the groove bottom portion. And a side wall portion. On the other hand, the “striated convex portion” refers to a portion formed as a protrusion on the material of the flow path forming member, and is formed on the protrusion protruding linearly from the material plane and on both ends of the protrusion. And having a side wall portion. In the present invention, these streak recesses and streak projections are alternately formed on the material, and the cross-sectional uneven shape is in a state where the adjacent streak recesses and the side walls of the streak projections are sequentially shared. It is formed continuously.

  Another feature of the present invention is that the shape of the through holes formed in the first opening and the second opening is similar, and the formation interval of the through holes formed in the first opening Is to be narrower than the formation interval of the through holes formed in the second opening. By forming the first opening and the second opening in this manner, both parts can be formed with the same punch, so that a molding apparatus for molding both parts is made common. The gas flow path forming member according to the present invention can be manufactured at a low cost.

  Another feature of the present invention is used for a gas flow path forming member in which a gas flow path for supplying a fuel gas and an oxidant gas to an electrode layer constituting an electrode structure of a fuel cell is formed. A through-hole forming device for forming a large number of through-holes in a thin-walled material, a punch having a blade portion for forming a large number of through-holes in the thin-walled material, and a feeding device for feeding the thin-walled material to the punch A first opening for forming a plurality of through holes in the thin material with a first opening ratio, and a second opening for forming a plurality of through holes with a second opening ratio lower than the first opening ratio. The present invention provides a through-hole forming device including a control means for controlling the punch and / or the feeding device so that the portions are alternately formed in layers.

  According to the present invention, the through hole forming device includes a punch that forms a through hole in the material, a feed device that feeds the material to the punch, and a control unit that controls the punch and / or the feed device. And a control means forms the 1st opening part and the 2nd opening part in a layer form in a raw material by controlling at least any one of drive control of a punch, or feed control of a feeder. Thus, the apparatus which shape | molds the gas flow path formation member which concerns on this invention with a simple apparatus structure can be provided. In this case, the control means can control the feed amount of the thin material by the feed device when the through hole is formed in the first opening. For example, the feed device has a feed roller and a step motor for driving the feed roller, and the drive by the step motor is controlled so that the feed amount of the feed roller is different between the first opening and the second opening. Can do. Further, the control means sets the through-hole formation time interval by the blade portion when forming the through-hole in the first opening portion, and the through-hole formation time interval by the blade portion when forming the through-hole in the second opening portion. The punch can be controlled to be shorter. For example, an actuator that drives the blade portion can be controlled so that the reciprocating cycle of the blade portion of the punch is different between the first opening and the second opening.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a gas flow path forming member 10 used in a fuel cell and constituting a metal separator of the fuel cell. The gas flow path forming member 10 supplies a fuel gas and an oxidant gas (hereinafter simply referred to as a gas) supplied to the electrodes (anode electrode and cathode electrode) constituting the fuel cell from the outside. The electricity generated by the electrode reaction is collected. For this reason, the shape of the gas flow path forming member 10 is required to efficiently collect the generated electricity in addition to efficiently supplying the gas supplied from the outside to each electrode. That is, in order to efficiently supply the gas supplied from the outside to each electrode, the shape is required to reduce the pressure loss of the gas that is conducted. On the other hand, in order to efficiently collect the generated electricity, it is required to have a shape that increases the contact area with each electrode and reduces the current collection resistance.

  Therefore, as shown in FIG. 1, the gas flow path forming member 10 has a large number of streak-like recesses 12 with respect to the lath cut metal 11 in which a large number of mesh-like through holes are formed in order to reduce the pressure loss of the conducting gas. And the line-shaped convex part 13 is shape | molded. Further, in order to reduce the current collecting resistance, the streak-shaped recess 12 is formed so that the streak-shaped recess 12 has a larger width than the streak-shaped protrusion 13. Furthermore, the aperture ratio of the through-hole formed in the groove bottom part of the streak-like recessed part 12 is made higher than the aperture ratio of the through-hole formed in the other part. That is, assuming that the opening ratio of the groove bottom of the streak-shaped recess 12 is the first opening ratio and the opening ratio of the other portions is the second opening ratio, the second opening ratio is lower than the first opening ratio. Hereinafter, the production of the gas flow path forming member 10 will be described in detail.

  The thin-cut metal 11 as a thin material is made of a stainless steel plate having a thickness of about 0.1 mm to 0.2 mm, and a large number of small diameter through holes having a hole diameter of about 0.1 mm to 1 mm are formed in a mesh shape. It is what is done. As shown in FIG. 2, the lath cut metal 11 according to the present embodiment has substantially the same opening shape (similar shape), but the first opening 11a and the second opening have different through hole formation intervals. 11b. As shown in the figure, the first opening portion 11a has a through hole formed at a first opening ratio with a narrow interval between through holes and a high opening ratio (ratio of the opening area per unit area). On the other hand, as shown in the figure, the second opening portion 11b has a through hole formed at a wide opening interval and a second opening ratio that is lower than the first opening portion 11a. The lath cut metal 11 having such a shape is manufactured through a lath cut metal forming step (opening forming step) described below.

  In the last cut metal forming step, a number of mesh-like through holes are formed in the stainless steel plate S by using a last cut metal processing apparatus R schematically shown in FIG. The last cut metal processing apparatus R controls the feed roller OR for supplying the stainless steel plate S, the punch P for sequentially shearing the stainless steel plate S to form a mesh-like through hole, and the feed amount of the feed roller OR. A step motor M as a control device is provided. The stainless steel plate S may be a plate material cut in advance to a predetermined length, or may be a coil material wound in a coil shape. As shown in FIG. 3B, the punch P includes an upper blade UH that can move up and down and a lower blade SH that is fixed. The upper blade UH and the lower blade SH are provided with a plurality of ridges and valleys in order to form cuts in a staggered arrangement on the stainless steel plate S by shearing.

  In the lath cut metal forming process using the lath cut metal processing apparatus R configured as described above, first, the first opening 11a is formed in the material. In this case, the feed roller OR feeds the stainless steel plate S to the punch P by a predetermined processing length (processing pitch) L1 by driving the step motor M. When the stainless steel plate S is supplied by the feed roller OR, the upper blade UH of the punch P descends in the direction of the lower blade SH, and along with the lower blade SH, a part of the stainless steel plate S is sheared by the mountain-shaped portion, and the zigzag is cut. Process the alignment cuts. Furthermore, the upper blade UH descends to the lowest point position, and the stainless steel plate S that is in contact with the blade of the upper blade UH is bent and extended downward, and then returns to the upper original position. Subsequently, after the feed roller OR again feeds the stainless steel plate S to the blade die H by the processing pitch L1, the upper blade UH moves down to the left (right) by a half-valley shaped half pitch, and then the upper blade UH descends again. By doing so, cut processing and bending and stretching are performed.

  By repeating these operations, the lath cut metal 11 in which a large number of mesh-like through holes are formed at a formation interval equal to the processing pitch L1 is formed. Here, by providing valley portions in the upper blade UH and the lower blade SH, it is possible to provide a portion in which the cut is not processed in the stainless steel plate S as the upper blade UH is lowered. The portion where the cut is not processed becomes a bond portion 11c of the lath cut metal 11, and the lath cut metal 11 is formed in a step shape as shown in FIG.

  When the feeding operation of the processing pitch L1 and the shearing processing by the punch P are performed a predetermined number of times, the second opening 11b is then formed in the material. In this case, the feed roller OR feeds the stainless steel plate S to the punch P by the machining pitch L2 by driving the step motor M. Here, the processing pitch L2 is set longer than the processing pitch L1. Thus, when the stainless steel plate S is supplied from the feed roller OR at the processing pitch L2, the upper blade UH descends in the direction of the lower blade SH, and a part of the stainless steel plate S is sheared by the mountain-shaped portion together with the lower blade SH. Then cut the staggered cuts. Furthermore, the upper blade UH descends to the lowest point position, and the stainless steel plate S that is in contact with the blade of the upper blade UH is bent and extended downward, and then returns to the upper original position. Subsequently, after the feed roller OR again feeds the stainless steel plate S to the blade mold H by the machining pitch L2, and the upper blade UH moves to the left (right) by a half-valley shaped pitch, the upper blade UH descends again. By doing so, cut processing and bending and stretching are performed. Then, by repeating these operations, the lath cut metal 11 in which a large number of mesh-like through holes are formed at a formation interval equal to the machining pitch L2 is formed.

  As described above, when the stainless steel plate S is supplied to the punch P by the feed roller OR while alternately repeating the feed at the machining pitch L1 and the feed at the machining pitch L2, as shown in FIG. Lascut metal 11 in which first openings 11a in which through-holes are formed with an opening ratio of and second openings 11b in which through-holes are formed with a second opening ratio with a low opening ratio are alternately formed in layers. Can be produced. Here, in the opening forming step, since the processing pitch L1 is shorter than the processing pitch L2, the portion where the through holes are formed by the processing feed of the processing pitch L1 has a short through hole formation interval, and the through holes are densely formed. Is formed. On the other hand, in the portion where the through holes are formed by the processing feed at the processing pitch L2, the through holes are formed at long intervals, and the through holes are formed sparsely. Therefore, the portion formed by the machining feed at the machining pitch L1 becomes the first opening 11a, and the portion formed by the machining feed at the machining pitch L2 becomes the second opening 11b.

  Next, a detailed description will be given of a step of forming a large number of streak-like recesses 12 and streak-like projections 13 (irregularity forming step) on the lath cut metal 11 manufactured as described above. This step includes a first forming step of temporarily forming a concavo-convex shape on the lath cut metal 11 (hereinafter, this concavo-convex shape is referred to as a corrugated shape), and a streaky concave portion 12 on the lath cut metal 11 on which the corrugated shape is temporarily formed. And a second molding step for molding the streak-shaped convex portion 13.

  In the first molding step, a corrugated molding machine K as shown in FIG. The corrugating machine K includes a pinion gear-shaped pinion tool PT and a rack-shaped rack tool RT. The pinion tool PT has a dimension in the axial direction larger than the width dimension of the supplied lath cut metal 11, and is assembled coaxially and non-rotatably with respect to a shaft J connected to a drive device (not shown). ing. The rack tool RT is formed in a flat plate shape, and a rack shape that meshes with the pinion gear shape of the pinion tool PT is formed on the surface facing the pinion tool PT. The rack tool RT is accurately displaced in the axial direction (left-right direction in FIG. 4) in accordance with the rotation of the pinion tool PT by a feeding device (not shown). In addition, the height of the pinion gear shape formed on the pinion tool PT and the rack-shaped teeth formed on the rack tool RT are the molding dimensions of the corrugated irregularities formed in the first molding step (hereinafter referred to as the first dimension). The molding dimension) is set to be larger by a predetermined dimension ΔL than the final molding dimension L of the streak-like recess 12 and the streak-like convex part 13 to be molded in the second molding step described later.

  In the first forming step using the corrugating machine K configured as described above, the lath cut metal 11 manufactured as described above is continuously supplied to the meshing portion between the pinion tool PT and the rack tool RT. . Thus, when the lath cut metal 11 is supplied, the pinion tool PT starts to rotate by the driving force transmitted from the driving device via the shaft J. Further, the rack tool RT starts to be displaced in the axial direction by the feeding device in accordance with the rotation of the pinion tool PT. As a result, as shown in FIG. 5A, the lath cut metal 11 is continuous at the meshing portion of the pinion tool PT and the rack tool RT (specifically, the meshing portion of the pinion gear shape and the rack-shaped teeth). A wave shape is formed. In this case, the first opening 11a and the second opening 11b are alternately formed in layers in the lath cut metal 11 in the opening forming step, but the first opening 11a is formed in the protruding portion T of the rack tool RT. The lath cut metal 11 is set so as to be positioned and processed. And the 1st shaping | molding dimension in the height direction of the waveform shape shape | molded by the 1st shaping | molding process on the lath cut metal 11 is shape | molded larger by (DELTA) L than the last shaping | molding dimension L, as shown in FIG.5 (b). In other words, the corrugated shape forming direction of the lath cut metal 11 formed in the first forming step as compared with the cross-sectional length of the cross section in the forming direction of the streaky concave portion 12 and the streaky convex portion 13 of the gas flow path forming member 10. The cross-sectional length of the cross section is formed so as to be large (long).

  In this way, the lath cut metal 11 having the waveform shape continuously formed in the first forming step is cut so as to be equal to the product size of the gas flow path forming member 10 and supplied to the second forming step. The second forming step is a step of forming the streaky concave portion 12 and the streaky convex portion 13 as the final shape with respect to the lath cut metal 11 having a corrugated shape to form the gas flow path forming member 10. In the second molding step, as shown schematically in FIG. 6A, the streak-like recess 12 and the streak-like projection 13 are press-molded using a press molding machine O. The press molding machine O includes a lower mold SO fixed on the floor surface and an upper mold UO that is arranged above the lower mold SO and can move up and down. And the surface where these lower mold | type SO and upper mold | type UO oppose is formed in the uneven | corrugated shape for shape | molding the stripe-shaped recessed part 12 and the stripe-shaped convex part 13. As shown in FIG. Here, the formation width of the concave shape and the convex shape formed in the lower mold SO and the upper mold UO is set such that the formation width of the concave shape is larger than the formation width of the convex shape. Further, the formation depth of the concave shape and the formation height of the convex shape are set to be substantially equal to the final molding dimension L.

  In the final molding process using the press molding machine O configured in this way, first, the lath cut metal 11 molded in the first molding process is placed on the upper surface of the lower mold SO on which the concavo-convex shape is formed. In this placement, as shown in FIG. 6A, the corrugated irregularities formed on the lath cut metal 11 are placed so as to coincide with the irregularities formed on the lower mold SO. In this state, when the upper mold UO descends in the direction of the lower mold SO, the concave and convex shapes formed on the lower mold SO and the upper mold UO cause streaky recesses in the lath cut metal 11 as shown in FIG. 12 and the line-shaped convex part 13 are formed. Here, the streak-like recesses 12 and the streak-like projections 13 of the formed lath cut metal 11 are formed between the lower mold SO and the upper mold UO, so that the bond 11c is compressed to form a substantially flat shape. The

  Here, as described above, the molding dimension of the corrugated shape molded by the first molding process is L + ΔL, and the final molding dimension of the streak-like recess 12 and the streak-like convex part 13 molded by the second molding process is L. It has become. For this reason, in the final forming step, the streak-like recesses 12 and the streak-like protrusions 13 are formed while compressing the lath cut metal 11, in other words, reducing the cross-sectional length of the cross-section in the waveform forming direction. Thereby, it is possible to effectively prevent the corner portions of the streak-like recesses 12 and the streak-like projections 13 that are bent at a substantially right angle from being excessively extended (pulled). For this reason, even if it is a thin-walled material that has undergone work hardening by shearing, such as the lath cut metal 11, it can be easily bent without being cracked or broken.

  That is, the lath cut metal 11 is hardened around the bond portion 11c by shearing or bending to form a mesh-like through-hole at the time of manufacture. For this reason, when the streak-like concave portion 12 and the streaky convex portion 13 are formed without performing the first molding described above, for example, the bond portion 11c exists at the corner portion of the streaky concave portion 12 or the streaky convex portion 13. If it does, the elongation accompanying bending will be insufficient, and cracks and breaks will occur at the bond portion 11c. On the other hand, once the corrugated shape is once formed on the lath cut metal 11 and the streak-like recess 12 and the streak-like projection 13 are formed while being compressed, the surplus metal (specifically, the strand) of the last cut metal 11 is squared. Can flow toward the part. Therefore, since the bond part 11c is not extended excessively with a bending process, a bending process can be performed suitably.

  Moreover, in this 2nd shaping | molding process, although the wide part shape | molded by the 1st shaping | molding process is shape | molded in the part of the groove bottom part of the streaky recessed part 12, as above-mentioned, this part is 1st opening with a high opening ratio. It is the 1st opening part 11a in which the through-hole was formed at a rate. On the other hand, the aperture ratio of the other part is the 2nd opening part 11b in which the through-hole was formed with the 2nd aperture ratio. Here, the first aperture ratio is an aperture ratio higher than the second aperture ratio. Therefore, the lath cut metal 11 produced in this way has a high opening ratio only at the groove bottom of the streak-like recess 12.

  The lath cut metal 11 manufactured through the opening forming step and the concavo-convex forming step is made to have a predetermined size to be the gas flow path forming member 10. The gas flow path forming member 10 is used as a metal separator constituting a solid polymer fuel cell. The configuration of the polymer electrolyte fuel cell is not directly related to the present invention, and therefore a detailed description thereof is omitted, but will be briefly described below.

  The polymer electrolyte fuel cell is configured by laminating a large number of single cells whose structure is shown in FIG. In the single cell, a metal separator composed of the gas flow path forming member 10 and the metal thin plate 20 described above is arranged up and down, and two resin frames 30 and an MEA 40 (Membrane-Electrode Assembly: membrane-electrode) are disposed between the metal separators. Assembly). For each unit cell, fuel gas such as hydrogen gas and oxidant gas such as air are introduced from the outside of the fuel cell stack, and electricity is generated by the electrode reaction in the MEA 40.

  The metal thin plate 20 is used to prevent a mixed flow of gas introduced from the outside and introduce gas into each single cell when a large number of single cells are stacked. For this reason, the metal thin plate 20 has a gas introduction port 21 for introducing a fuel gas and an oxidant gas, and a gas outlet port 22 for discharging unreacted fuel gas and oxidant gas in the MEA 40, respectively. Is formed.

  The resin frame 30 has a shape of each through hole at a position corresponding to each through hole of the gas inlet port 21 and the gas outlet port 22 formed in the thin metal plate 20 in a state where a single cell is formed in the peripheral portion. Through holes 31 and 32 having substantially the same shape are formed. The resin frame 30 is formed with an accommodation hole 33 for accommodating the gas flow path forming member 10 at a substantially central portion thereof. The accommodation hole 33 also accommodates a pair of gas inlets 21 and gas outlets 22 formed in the metal thin plate 20 to be fixed, and through holes 31 and 32 formed in the other resin frame 30 to be laminated. It is formed to do.

  Thus, by forming the accommodation hole 33, a space (hereinafter referred to as a gas) is formed by the lower surface (or upper surface) of the metal thin plate 20 to be fixed, the inner peripheral surface of the accommodation hole 33 and the upper surface (or lower surface) of the MEA 40. A conductive space) is formed. For example, fuel gas is introduced into the gas conduction space from one gas inlet 21 of the thin metal plate 20, and oxidant gas is introduced from the other gas inlet 21 and the through hole 31 of the resin frame 30. be able to. The unreacted gas that has passed through the gas conduction space is led out to the outside through one gas outlet 22 of the thin metal plate 20 and through the other gas outlet 22 and the through hole 32 of the resin frame 30. can do. The resin frame 30 has a thickness slightly smaller than the molding height of the streak-like recess 12 and the streak-like projection 13 of the gas flow path forming member 10.

  The MEA 40 as the electrode structure includes an electrolyte membrane EF. On the surface of the electrolyte membrane EF, an anode electrode arranged on the gas conduction space side where the fuel gas is introduced and a cathode electrode arranged on the gas conduction space side where the oxidant gas is introduced are predetermined It is formed by laminating the catalyst in layers.

  A single cell is configured by laminating the gas flow path forming member 10, the resin frame 30 and the MEA 40 between the two separator bodies 20. More specifically, the MEA 40 is sandwiched between the resin frames 30 that are arranged to be rotated by approximately 90 ° in the same plane, and an adhesive or the like is applied, for example, to thereby apply the electrolyte of the MEA 40 between the resin frames 30. The membrane EF is fixed integrally. For example, an adhesive is applied to the two separator main bodies 20 in a state where the gas flow path forming member 10 is accommodated in the accommodation hole 33 to the resin frame 30 and the MEA 40 that are integrally fixed in this manner. By doing so, it is fixed integrally.

  At this time, as shown in FIG. 8, the gas flow path forming member 10 is disposed so that the streak-shaped concave portion 12 having a wide molding width and the MEA 40 (specifically, the carbon cloth CC) are in contact with each other. Further, since the thickness of the resin frame 30 is slightly smaller than the molding height of the streak-like recess 12 and the streak-like projection 13, the streak-like recess 12 is slightly pressed toward the MEA 40 by the separator body 20. It is fixed in a state. Thereby, the contact state of the gas flow path forming member 10 and the MEA 40 can be kept good. Then, after a large number of single cells formed in this way are stacked, they are fixed with a predetermined fastening force by bolts and nuts (not shown) to constitute a fuel cell stack.

  In the polymer electrolyte fuel cell in which a large number of single cells configured as described above are stacked, the fuel gas and oxidation are applied to the anode electrode and cathode electrode of the MEA 40 by the gas flow path forming member 10 manufactured through the above-described steps. The agent gas can be supplied efficiently. Specifically, the gas flow path forming member 10 is configured by forming a thin concave portion 12 and a linear convex portion 13 in a thin lath cut metal 11. For this reason, the gas introduced into the gas conduction space from the outside via the gas introduction port 21 can conduct the streak-like recess 12 or the streak-like projection 13 to significantly reduce the pressure loss. In addition, since the lath cut metal 11 has a large number of mesh-like through holes, the gas introduced into the gas conduction space is very easily between the streak-like recess 12 and the streak-like projection 13 through the through-hole. Can penetrate. In particular, in the flow path forming member 10 manufactured in the present embodiment, the opening ratio of the through hole formed in the groove bottom portion of the streak-shaped recess 12 that is in contact with the MEA 40 is higher than other portions. The gas supplied from the gas flow path forming member 10 diffuses well into the MEA 40 from the portion with the high aperture ratio. Therefore, gas can be efficiently supplied to each electrode, and the power generation efficiency of the polymer electrolyte fuel cell can be improved. In addition, since the opening ratio of the portion other than the groove bottom of the streak-shaped recess of the gas flow path member is low, the mechanical strength does not decrease with the increase in the opening ratio. Therefore, it is possible to provide a gas flow path forming member for a fuel cell separator in which gas is satisfactorily supplied and mechanical strength is sufficiently secured.

  In the above embodiment, the case where the gas flow path forming member is manufactured using the lath cut metal 11 has been described. However, in addition to the lath cut metal 11, the present invention is implemented by forming an appropriate through hole in the material. Can do. Another example of forming an appropriate through hole in the material is an example using expanded metal. The expanded metal is formed from a stainless steel plate having a plate thickness of about 0.1 mm to 0.2 mm, similar to the aforementioned lath cut metal 11. In the expanded metal, a large number of small-diameter through-holes having a hole diameter of about 0.1 mm to 1 mm are formed in a mesh shape. The expanded metal 14 is manufactured by adding a rolling process to the opening forming process in the above-described lath cut metal.

  In the added rolling process, the lath cut metal 11 manufactured as described above is rolled using a rolling machine A schematically shown in FIG. The rolling machine A includes a pair of upper and lower rolling rollers AR, and rolls the supplied lath cut metal 11. Thereby, the bond part 11c of the lath cut metal 11 is rolled (stretched) by the rolling roller AR, and the expanded metal 14 is manufactured. The expanded metal 14 manufactured in this way also has first openings 11a and second openings 11b alternately formed in layers in the opening forming process before the rolling process (see FIG. 2). Then, the streak-like recess and the streak-like convex part are formed in the unevenness forming process after the rolling process. At this time, the unevenness is so formed that the first opening part 11a having a high opening ratio becomes the groove bottom part of the streak-like recessed part 12. It is formed.

  When the gas flow path forming member 10 thus manufactured is used as the gas flow path forming member of the fuel cell separator, the gas flow path forming member is assembled by assembling the groove bottom portion of the streak-shaped recess 12 as the side in contact with the MEA 40. The gas supplied from 10 diffuses well into the MEA 40 from the portion with a high aperture ratio. Therefore, gas can be efficiently supplied to each electrode, and the power generation efficiency of the polymer electrolyte fuel cell can be improved. In addition, since the opening ratio of the portion other than the groove bottom portion of the streak-shaped recess 12 of the gas flow path forming member 10 is low, the mechanical strength is not lowered with the increase in the opening ratio. Therefore, it is possible to provide the gas flow path forming member 10 of the fuel cell separator in which the gas is satisfactorily supplied and the mechanical strength is sufficiently secured.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment and modification, A various deformation | transformation is possible. In the said embodiment and modification, in the opening formation process, the 1st opening part 11a which forms many through-holes in a raw material with a 1st opening ratio, and the 2nd opening part 11b which forms with a 2nd opening ratio In this example, the feed amount by the feed roller OR is controlled in order to form the layers alternately. Specifically, by controlling the driving of the feed roller OR by the step motor M, the feed amount (feed pitch L1) when the through hole is formed in the first opening portion 11a is changed to the through hole in the second opening portion 11b. In this example, the feed roller is controlled so as to be smaller than the feed amount (feed pitch L2) when forming the. However, the present invention can also be realized by other methods. For example, the feed amount by the feed roller OR is always constant, and instead, the formation time interval (the number of formations per unit time) of the upper blade UH of the punch P when the through hole is formed in the first opening 11a The present invention can also be realized by controlling the punch P so as to be shorter (faster) than the formation time interval when the through hole is formed in the two openings 11b. In this case, an actuator for reciprocating the upper blade UH may be controlled.

It is the schematic which shows the flow-path formation member of the metal separator for fuel cells manufactured by the streak uneven | corrugated shaping | molding method which concerns on embodiment of this invention. It is a figure which shows the formation state of the through-hole formed in the lath cut metal used for the flow-path formation member which concerns on embodiment of this invention. (A), (b) is a figure for demonstrating the lath cut manufacturing process which manufactures the lath cut metal of FIG. It is a figure for demonstrating the 1st shaping | molding process which shape | molds a waveform shape in the lath cut metal of FIG. (A), (b) is a figure for demonstrating the waveform shape shape | molded by a 1st shaping | molding process. (A) is the schematic for demonstrating a 2nd shaping | molding process, (b) is a figure for demonstrating the streaky recessed part and streaky convex part shape | molded by a 2nd shaping | molding process. It is a schematic exploded perspective view for demonstrating the structure of the fuel cell by which the flow-path formation member of FIG. 1 was employ | adopted. It is the cross-sectional schematic of the single cell in the fuel cell which employ | adopted the flow-path formation member produced in embodiment of this invention. It is a figure for demonstrating the rolling process which manufactures the expanded metal of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Channel formation member, 11 ... Lascut metal, 11a ... 1st opening part, 11b ... 2nd opening part, 11c ... Bond part, 12 ... Streaky recessed part, 13 ... Streaky convex part, 14 ... Expanded metal, 20 ... Metal thin plate, 30 ... Resin frame, 40 ... MEA, R ... Lascut metal processing device (through-hole forming device), OR ... Feed roller (feed device), M ... Step motor (control means), P ... Punch, UH ... Upper blade (blade part), SH ... lower blade (blade part), K ... corrugating machine, O ... press molding machine, A ... rolling molding machine

Claims (11)

A method for producing a gas flow path forming member in which a gas flow path for supplying a fuel gas and an oxidant gas to an electrode layer constituting an electrode structure of a fuel cell is formed,
A first opening in which a plurality of through holes are formed in a thin material with a first opening ratio, and a second opening in which a plurality of through holes are formed with a second opening ratio lower than the first opening ratio Forming openings alternately in layers, and
Concave and convex forming that alternately forms a plurality of streaky concave portions and streaky convex portions as the gas flow path in the thin material so that the first opening portion formed by the opening forming step becomes a groove bottom portion of the concave portion. And a process for producing a gas flow path forming member. In Claim 1, The shape of the through-hole formed in said 1st opening part and said 2nd opening part is substantially the same shape, The formation space | interval of the through-hole formed in said 1st opening part is said 1st. A method for manufacturing a gas flow path forming member, characterized in that it is narrower than the interval between through holes formed in two openings. 3. The gas flow path forming member according to claim 1, wherein the opening forming step is a step of forming a lath cut metal in which a large number of through holes are formed in a mesh shape by shear bending processing on the thin material. Manufacturing method. 4. The gas flow according to claim 3, further comprising a rolling step after obtaining the expanded metal by forming a lath-cut metal into a substantially flat plate shape by a rolling process after the opening forming step and before the concavo-convex forming step. A method for manufacturing a path forming member. In a gas flow path forming member of a fuel cell metal separator that forms gas flow paths for supplying a fuel gas and an oxidant gas to an electrode layer constituting an electrode structure of a fuel cell,
The gas flow path forming member includes a first opening in which a plurality of through holes are formed in a thin material at a first opening ratio, and a plurality of through holes at a second opening ratio lower than the first opening ratio. A plurality of streak-shaped recesses as the gas flow path in the thin material so that the formed second openings are alternately formed in layers, and the formed first openings are the groove bottoms of the recesses. And a gas flow path forming member formed by alternately forming streak-shaped convex portions. 6. The shape of the through holes formed in the first opening and the second opening is substantially the same shape according to claim 5, and the formation interval of the through holes formed in the first opening is the first. A gas flow path forming member characterized by being narrower than an interval between through holes formed in two openings. 7. The first opening and the second opening according to claim 5 or 6, wherein the thin material is a lath cut metal in which a large number of through holes are formed in a mesh shape by a shear bending process on a flat metal thin plate. A gas flow path forming member characterized by being molded. In claim 5 or 6, as the expanded metal formed into a substantially flat plate shape by rolling after forming a plurality of through holes in a mesh shape by a shear bending process on a flat plate metal thin plate, The gas flow path forming member, wherein the first opening and the second opening are formed. A large number of through holes are formed in a thin material used for a gas flow path forming member in which gas flow paths for supplying fuel gas and oxidant gas are formed to the electrode layers constituting the electrode structure of the fuel cell. A through-hole forming device to be formed,
A punch having a blade portion for forming a plurality of through holes in the thin material;
A feeding device for feeding the thin material to the punch;
A first opening for forming a plurality of through holes in the thin material with a first opening ratio, and a second opening for forming a plurality of through holes with a second opening ratio lower than the first opening ratio; And a control means for controlling the punch and / or the feeding device so as to be alternately formed in layers. 10. The control unit according to claim 9, wherein the control unit is configured to determine a feed amount of the thin material by the feeding device when the through hole is formed in the first opening, and the when the through hole is formed in the second opening. The through-hole forming apparatus characterized by controlling the said feeding apparatus so that it may become smaller than the feed amount of the said thin raw material by a feeding apparatus. 10. The control device according to claim 9, wherein the control means sets a through-hole formation time interval by the blade portion when the through-hole is formed in the first opening, and the blade when the through-hole is formed in the second opening. The punch is controlled so as to be shorter than the formation time interval of the through hole by the portion.

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