JP2005349463A - Method for forming stripe-shaped convex and concave, and metal separator for fuel cell manufactured in the same method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming stripe-shaped convexes and concaves, which beautifully forms a plurality of stripe-shaped concaves and stripe-shaped convexes on a thin material in which a number of through holes are formed reticulately. <P>SOLUTION: The method for forming stripe-shaped concaves and convexes comprises a preliminary forming step and a final forming step. In the preliminary forming step, wavy patterns larger than those to be formed at the final forming step are formed on a lance-cut metal 11 in which a number of through holes are formed. In the final forming step, a plurality of stripe-shaped concaves 12 and stripe-shaped convexes 13 are formed on the lance-cut metal 11 subjected to the preliminary forming, and the wavy patterns on the lance-cut metal 11 are compressed to the final dimensions. The invented method can restrain the elongation of the bent portion of the lance-cut metal 11 which is greatly work-hardened, thereby preventing cracking or fracture. This enables the stripe-shaped concaves 12 and stripe-shaped convexes 13 to be formed beautifully on the lance-cut metal 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of forming a plurality of streak-like recesses and streak-like projections on a thin-walled material, in particular, a thin-walled material having a large number of through-holes formed in a mesh shape, and the same molding The present invention relates to a metal separator for a fuel cell manufactured by the method.

  Conventionally, for example, a structure of a fuel cell as shown in Patent Document 1 below is known. The metal separator in the structure of the fuel cell includes a current collector that supports the anode electrode or the cathode electrode, and a current collector support that forms a flow path for supplying fuel gas or oxidant gas to each electrode. It has become. 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 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 includes a flat plate-like first member (carbon) and a plurality of projecting pieces that are stacked on the first member and elastically contact the electrode layer of the fuel cell and form a gas flow path. And a second 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 the demand for such a fuel cell, for example, if a large number of grooves are formed in the expanded metal, the electrode passes through the through hole of the expanded metal while ensuring good contact with each electrode. The gas diffusibility to the layer can be ensured satisfactorily. 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, in a thin metal plate having a large number of through-holes such as expanded metal, work hardening (that is, concentration of residual stress) occurs during the formation of the through-holes, and there is a possibility that cracks and breaks may occur very easily when bent. .

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to provide a plurality of streak-like recesses and streak-like projections with respect to a thin material having a large number of through holes formed in a mesh shape. An object of the present invention is to provide a method for forming streak irregularities to be molded and to provide a separator for a fuel cell manufactured by the method for forming streak unevenness.

  In order to achieve the above object, a feature of the present invention is a streak uneven forming method for forming a plurality of streak recesses and streak protrusions on a thin material having a large number of through holes formed in a mesh shape. And pre-molding a corrugated shape including a plurality of concave portions and convex portions with a preforming dimension larger than a final molding size of the plurality of streaky concave portions and streaky convex portions with respect to the thin material, The plurality of streak-like recesses or streak-like projections are finally molded by being deformed while being compressed until the preformed dimensions of the shaped corrugated recesses and projections become the final molding dimensions. In this case, the thin material may be, for example, a lance 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.

  According to these, for a thin material in which a large number of through holes such as lance cut metal are formed in a mesh shape, a corrugated shape that is a gentle uneven shape is first formed by preforming so as to have a pre-formed dimension. Then, the final streak-like recesses and streak-like projections can be formed by being deformed while being compressed until reaching the final molding size. As a result, even if it is a thin material that is prone to cracking or breaking due to the effects of work hardening during the formation of through-holes, the thin material is compressed when final forming the streak-like recess and streak-like projection. However, in other words, it is possible to perform molding while reducing the dimensions of the corrugated concave and convex parts formed with the preforming dimensions. Therefore, the local elongation with respect to the bending process of the thin-walled material can be reduced, and the occurrence of cracks and breaks can be reduced. Here, the lance cut metal is formed by sequentially processing staggered cuts on a flat thin metal plate and by pressing and bending the cut cuts to form a mesh-like small-diameter through hole. .

  Another feature of the present invention is that the thin-walled material is a thin-walled material that is rolled after a large number of through holes are formed in a mesh shape. The waveform shape may be preformed in a direction different from the processed direction. In this case, the thin-walled material may be, for example, an expanded metal formed in a substantially flat plate shape by rolling after forming a large number of through holes in a mesh shape by a shear bending process on a flat metal thin plate. .

  According to these, for a thin material rolled after a large number of through-holes such as expanded metal are formed in a mesh shape, a pre-molding is formed into a wave shape in a direction different from the rolled direction, and thereafter Then, by deforming while compressing to the final molding dimension and finally forming the final streak-like concave part and the streak-like convex part, the occurrence of cracks and breaks can be reduced. Specifically, when a thin material that has undergone work hardening due to the formation of a through hole is rolled, the thin material further undergoes work hardening in the rolling direction. When bent, the elongation is extremely insufficient, and cracks and breaks tend to occur. For this reason, in preforming and final forming, it is possible to ensure the elongation necessary for bending by forming a corrugated shape, streak-like concave part and streak-like convex part in a direction different from the rolling direction, and cracking or breaking Can be reduced. Here, the expanded metal is formed by sequentially processing staggered cuts on a flat thin metal plate, and forming a small through-hole with a mesh shape by pressing and bending the cuts, and further rolling. It is made into a substantially flat plate shape. Thus, by making the expanded metal into 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 molding, and the manufacturing cost can be reduced. .

  In these cases, the preforming dimension of the preforming and the final molding dimension of the final molding are preferably dimensions in the concavo-convex forming direction of the plurality of streak-like recesses or streak-like projections. According to this, a preforming dimension and a final molding dimension can be made into the dimension of the depth direction of a streak-like recessed part, and the dimension of the height direction of a streak-like convex part, for example. Here, when forming a streak-like concave part and a streak-like convex part in a thin-walled material in which a large number of through-holes are formed in a mesh shape, or a thin-walled material that has been further rolled, Elongation with respect to bending work is required at the corners of the protrusions. For this reason, by setting the preforming dimension and the final molding dimension to the dimension in the depth direction of the streak recess and the dimension of the height method of the streak convex part, in the compression deformation at the time of final molding, the surplus of the thin material Can flow toward the corner. Accordingly, the elongation of the corner portion with respect to the bending process can be reduced, and the occurrence of cracks and breaks can be reduced.

  In these cases, the preforming continuously forms the corrugated shape on the thin-walled material, and the final forming continuously compresses the corrugated shape continuously formed by the preforming. The streak-shaped concave part and the streak-shaped convex part may be formed by being deformed while being deformed. According to this, since a streak-like recessed part and a streaky convex part can be continuously shape | molded with respect to a thin raw material, productivity can be improved significantly.

  Furthermore, another feature of the present invention is a metal separator for a fuel cell that forms a gas flow path for supplying a fuel gas and an oxidant gas to an electrode layer constituting an electrode structure of the fuel cell. The gas flow path of the metal separator is composed of a plurality of streak-like recesses and streak-like projections formed on a thin material in which a large number of through holes are formed in a mesh shape. The streak-like recess and the streak-like convex part have a preformed dimension larger than the final molding size of the plurality of streak-like recesses and the streak-like convex part with a wavy shape composed of a plurality of recesses and convex parts for the thin material. The preformed corrugated recesses and projections may be deformed while being compressed until the final molding dimensions are reached.

  According to this, a plurality of streak recesses and streak projections formed on a thin material (lance cut metal or expanded metal) in which a large number of through holes are formed in a mesh shape by the above-described streak uneven forming method. A metal separator for a fuel cell can be manufactured by molding the part. According to the manufactured metal separator for a fuel cell, the fuel gas or the oxidant gas passes through through holes formed in a thin material while ensuring good contact with the anode electrode or the cathode electrode. As a result, good gas diffusibility to the electrode layer can be secured. Thereby, 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. Therefore, the power generation efficiency of the fuel cell can be improved.

  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.

  Accordingly, as shown in FIG. 1, the gas flow path forming member 10 has a large number of streak-like recesses with respect to the lance 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. 12 and the line-shaped convex part 13 are shape | molded. Moreover, in order to reduce current collection resistance, it shape | molds so that the shaping | molding width | variety of the streaky convex part 13 may become large compared with the shaping | molding width of the streaky recessed part 12. FIG. Hereinafter, the production of the gas flow path forming member 10 will be described in detail.

  The lance cut metal 11 as a thin material is formed from a stainless plate (for example, ferritic stainless steel) having a plate thickness of about 0.1 mm to 0.2 mm. As shown in FIG. 2A, the lance cut metal 11 is formed with a large number of small-diameter through-holes having a hole diameter of about 0.1 mm to 1 mm. Further, the lance cut metal 11 is a portion in which a mesh-like through-hole is formed (hereinafter, this portion is referred to as a strand) as shown in the XX cross section of FIG. 2A in FIG. Are connected so as to overlap each other (hereinafter, this connecting portion is referred to as a bond portion 11a), and the cross-sectional shape thereof is a step shape. The lance cut metal 11 is manufactured through a lance cut metal forming process described below.

  In the lance cut metal forming step, a large number of mesh-like through holes are formed in the stainless steel plate S using a lance cut metal processing apparatus R schematically shown in FIG. The lance cut metal processing apparatus R includes a feed roller OR for supplying the stainless steel plate S, and a blade die H for sequentially shearing the stainless steel plate S to form a mesh-like through hole. 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 blade mold H is composed of 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 lance cut metal forming process using the lance cut metal processing apparatus R configured as described above, first, the feed roller OR sends the stainless steel plate S to the blade mold H by a predetermined processing length (processing pitch). When the stainless steel plate S is supplied by the feed roller OR, the upper blade UH of the blade mold H descends in the direction of the lower blade SH and shears a part of the stainless steel plate S by the mountain-shaped portion together with the lower blade SH. Process 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, the feed roller OR again feeds the stainless steel plate S to the blade mold H by the machining pitch, and the upper blade UH descends again to perform cut processing and bending elongation processing.

  Then, by repeating these operations, the lance cut metal 11 having a large number of mesh-like through holes 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 11a of the lance cut metal 11, and the lance cut metal 11 is formed into a step shape as shown in FIG. Thereby, the lance cut metal 11 is manufactured by connecting the strands so as to sequentially overlap.

  Next, with respect to the lance cut metal 11 manufactured as described above, a large number of streak-like recesses 12 and streak-like projections 13 are formed to finally produce the gas flow path forming member 10. The molding process will be described in detail. This streak uneven forming step includes a preforming step of preforming a gentle uneven shape (hereinafter referred to as a corrugated shape) with respect to the lance cut metal 11, and a lance cut metal 11 with the corrugated shape pre-formed. And a final molding step of molding the streak-like recess 12 and the streak-like projection 13.

  In the preforming process, a corrugated forming 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 lance cut metal 11 and is assembled coaxially and non-rotatably with respect to a shaft J connected to a drive device (not shown). It has been. 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). The height of the tooth of the pinion gear shape formed on the pinion tool PT and the rack shape formed on the rack tool RT is the molding dimension of the corrugated irregularities formed in the preforming process (hereinafter referred to as the preforming 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 final molding process described later.

  In the pre-forming process using the corrugating machine K configured as described above, the lance 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 lance 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. Thereby, as shown in FIG. 5A, the lance 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 waveform shape is formed. And the preforming dimension in the height direction of the waveform shape formed on the lance cut metal 11 by the preforming step is formed larger than the final forming dimension L by ΔL as shown in FIG. In other words, the cross-sectional length of the preliminarily formed lance cut metal 11 in the corrugated shape forming direction compared to 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. It is molded so that the cross-sectional length is large (long).

  Thus, the lance cut metal 11 in which the waveform shape is continuously formed by the preforming process is cut so as to be equal to the product size of the gas flow path forming member 10 and supplied to the final forming process. The final forming step is a step of finally manufacturing the gas flow path forming member 10 by forming the streak-like concave portion 12 and the streaky convex portion 13 as the final shape with respect to the lance cut metal 11 having a pre-shaped wave shape. It is. In this final forming step, as shown schematically in FIG. 6A, the streak-like recess 12 and the streak-like projection 13 are press-molded using a press-forming 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 forming step using the press molding machine O configured as described above, first, the preliminarily formed lance cut metal 11 is placed on the upper surface on which the uneven shape of the lower mold SO is formed. In this placement, as shown in FIG. 6 (a), the corrugated irregularities formed on the lance cut metal 11 are placed so as to coincide with the irregularities formed on the lower mold SO. In this state, when the upper die UO descends in the direction of the lower die SO, the uneven shape formed in the lower die SO and the upper die UO causes streaks on the lance cut metal 11 as shown in FIG. A recess 12 and a streak 13 are formed. Here, the streak-like recess 12 and the streak-like projection 13 of the finally formed lance cut metal 11 are sandwiched between the lower mold SO and the upper mold UO, so that the bond portion 11a is compressed and becomes substantially planar. It is formed.

  Here, as described above, the pre-formed dimension of the corrugated shape formed by the pre-forming process is L + ΔL, and the final formed dimensions of the streak-shaped recess 12 and the streak-shaped convex part 13 formed by the final forming process are L and It has become. For this reason, in the final forming step, the streak-shaped recess 12 and the streak-shaped protrusion 13 are formed while compressing the lance 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 a thin material having undergone work hardening, such as the lance cut metal 11, can be easily bent without being cracked or broken.

  That is, when the lance cut metal 11 is manufactured, work hardening occurs around the bond portion 11a by shearing or bending for forming a mesh-like through hole. For this reason, when the streak-like concave portion 12 and the streaky convex portion 13 are formed without performing the above-described preliminary molding, for example, the bond portion 11a exists at the corner portion of the streaky concave portion 12 or the streaky convex portion 13. If so, the elongation associated with the bending process is insufficient, and cracks and breaks occur at the bond portion 11a. On the other hand, if the corrugated shape is preformed on the lance cut metal 11 and the streak-like concave portion 12 and the streaky convex portion 13 are formed while being compressed, the surplus of the lance cut metal 11 (specifically, strand) Can flow toward the corners. Therefore, since the bond part 11a is not extended excessively with a bending process, a bending process can be performed suitably.

  The gas flow path forming member 10 manufactured in this way is used as a metal separator constituting a polymer electrolyte 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 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.

  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. If it demonstrates concretely, the gas flow path formation member 10 will be comprised by shape | molding the stripe-shaped recessed part 12 and the stripe-shaped convex part 13 in the thin lance cut metal 11. FIG. 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. Further, since the lance cut metal 11 has a large number of mesh-shaped through holes, the gas introduced into the gas conduction space is extremely between the streak-like recesses 12 and the streak-like projections 13 through the through-holes. It can be easily transmitted. Also by this, the pressure loss of gas can be reduced, and the gas conduction in the gas conduction space becomes smooth. Therefore, gas can be efficiently supplied to each electrode, and the power generation efficiency of the polymer electrolyte fuel cell can be improved.

  Further, the forming width of the streak-like concave portion 12 and the streaky convex portion 13 of the gas flow path forming member 10 is formed so that the forming width of the streaky convex portion 13 is increased. For this reason, as shown in FIG. 7, the gas flow path forming member 10 is disposed so that the streaky convex portions 13 are in contact with the anode electrode and the cathode electrode formed on the MEA 40, whereby the anode electrode and the cathode are arranged. The contact area with the electrode can be increased. Moreover, the contact area with an anode electrode and a cathode electrode can be enlarged also by forming many through-holes in the lance cut metal 11. FIG. Therefore, the current collecting resistance at the time of collecting electricity generated by the MEA 40 can be extremely reduced, and the generated electricity can be collected efficiently.

  In the embodiment described above, the streak uneven forming step is performed in order to prevent cracks and breaks when the streak-like recess 12 and the streak-like convex 13 are formed by work hardening of the bond part 11a generated during the manufacture of the lance cut metal 11. It comprised and comprised from the preforming and the last shaping | molding process. However, according to the above-described streak unevenness forming step, the streak-like concave part and the streak-like convex part are suitably formed even for a thin-walled material that is more work-hardened, that is, a thin-walled material that is inferior in formability. The gas flow path forming member 10 can be manufactured. Hereinafter, a first modification of the above embodiment will be described in detail.

  Examples of the thin-walled material that has been hardened more than the lance cut metal 11 include an expanded metal 14 that is manufactured by further rolling the lance cut metal 11 manufactured as described above. . The expanded metal 14 is also formed from a stainless steel plate (for example, ferritic stainless steel, etc.) having a plate thickness of about 0.1 mm to 0.2 mm, similar to the lance cut metal 11 described above. In the expanded metal 14, as shown in FIG. 8A, 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. Then, the expanded metal 14 is stretched as compared with the bond portion 11a of the lance cut metal 11 by rolling, as shown in the YY cross section of FIG. 8 (a) in FIG. 8 (b). And has a substantially flat plate shape. The expanded metal 14 is manufactured through an expanded metal forming process described below. Although the forming process will be described below, the expanded metal 14 is manufactured by adding a rolling process to the lance cut metal manufacturing process described above, and therefore the rolling process for rolling the lance cut metal 11 will be described in detail. To do.

  In the added rolling process, the lance 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 lance cut metal 11. Thereby, the bond part 11a of the lance cut metal 11 is rolled (stretched) by the rolling roller AR, and the expanded metal 14 is manufactured.

  Unlike the lance cut metal 11, the expanded metal 14 manufactured in this way has a substantially flat plate shape. For this reason, in the bond part 14a of the expanded metal 14, the work hardening at the time of shaping | molding of a mesh-shaped through-hole and the work hardening at the time of a rolling process arise, and the work hardening has progressed further compared with the lance cut metal 11 It has become. In this state, the elongation necessary for forming the streak-like recess 12 and the streak-like projection 13 cannot be sufficiently ensured. For example, it is considered that cracking and breakage may occur even in the preforming for forming the corrugated shape. It is done. Therefore, in this first modification, when preforming or final forming is performed on the expanded metal 14 that has progressed work hardening, as shown in FIG. 8 (a), in a direction substantially orthogonal to the rolling direction. The waveform shape, the streak-like concave part 12 and the streak-like convex part 13 are formed. Thereby, it can prevent that the bond part 14a of the expanded metal 14 is further extended by the bending to a rolling direction.

  Specifically, in the case of preforming the expanded metal 14 manufactured as described above, the expanded metal 14 is adjusted so that the supply direction is substantially perpendicular to the rolling direction. Supplied. Then, the corrugating machine K preforms a corrugated shape on the supplied expanded metal 14 as in the above embodiment. Here, in the expanded metal 14 in which the corrugated shape is formed, for example, even when the bond portion 14a is bent, since the bending direction is orthogonal to the rolling direction, the elongation due to bending is secured. The frequency of occurrence of cracks and breaks can be reduced rather than bending in the rolling direction.

  Further, by forming the corrugated shape in a direction substantially perpendicular to the rolling direction, the proportion of the strands in the formed corrugated portion increases. For this reason, in the waveform-shaped molding, the strands with small work hardening are greatly deformed, so that the elongation of the bond portions 14a with high work hardening is suppressed, and the cracks and breaks of the bond portions 14a can be prevented. Thereby, a waveform shape can be shape | molded favorably as a whole. Here, in this preforming as well, in the same manner as in the above embodiment, the preforming was performed in comparison with the cross-sectional lengths of the cross sections in the molding direction of the streak-like recesses 12 and the streaky projections 13 of the gas flow path forming member 10 The expanded metal 14 is molded so that the cross-sectional length of the cross section in the waveform shape forming direction is large (long).

  Then, the preformed expanded metal 14 is formed with the streak-like recesses 12 and the streak-like projections 13 by the press molding machine O in the final forming step, as in the above embodiment. Also in this final forming step, the streak-like recess 12 and the streak-like protrusion 13 are formed while compressing the expanded metal 14, in other words, reducing the cross-sectional length of the cross-section in the waveform forming direction. Thereby, even if it is a thin raw material with large work hardening and inferior formability like the expanded metal 14, generation | occurrence | production of a crack and a fracture | rupture can be prevented and bending can be performed favorably. Further, the gas flow path forming member 10 manufactured by forming the streak-like recesses 12 and the streak-like projections 13 in the expanded metal 14 is also adopted in the polymer electrolyte fuel cell as in the above embodiment. can do.

  As can be understood from the above description, according to the first modified example, even when the thin metal material, that is, the expanded metal 14 having a large work hardening and inferior formability, is prevented from being cracked or broken in the streak uneven forming process. can do. Moreover, about the other effect, the effect similar to the said embodiment can be anticipated.

  In the above embodiment, the pre-formed lance cut metal 11 is cut so as to be equal to the product width of the gas flow path forming member 10, and the streak recess 12 and the streak protrusion as final shapes are formed by the press molding machine O. 13 was performed. On the other hand, in order to improve productivity, it is also possible to continuously form the streak-like recess 12 and the streak-like projection 13 without cutting into the lance cut metal 11 continuously preformed. . Hereinafter, this second modification will be described in detail.

  In the second modification, a progressive press molding machine T schematically shown in FIG. 10 is used instead of the press molding machine O used in the final molding process of the above embodiment. This progressive press molding machine T is for forming the concave portions and the linear convex portions 13 for forming the linear concave portions 12 with respect to the entire width direction of the lance cut metal 11 (the vertical direction in FIG. 10). And a punch P for forming the streak-like recess 12 and the streak-like protrusion 13 in the lance cut metal 11 by entering the recess formed in the lower die SG. And a leading pad SP for fixing the lance cut metal 11 during the formation of the punch P.

  In the final molding process using this progressive press molding machine T, first, as shown in FIG. 10 (a), the streak-like recess 12 and the streak-like projection 13 formed by the previous molding cycle are fed one step. And placed on the lower mold SG. Subsequently, as shown in FIG. 10B, the leading pad SP is lowered in the direction of the streak-shaped recess 12 formed by the previous forming cycle, and the lance cut metal 11 is sandwiched and fixed together with the lower die SG. In this manner, with the lance cut metal 11 fixed, the punch P is lowered together with the lance cut metal 11 in the direction of the recess formed in the lower die SG as shown in FIG. A streak-like recess 12 and a streak-like projection 13 are formed on the metal 11.

  As described above, by repeating the forming cycle schematically shown in FIGS. 10A to 10C, the streak-like recess 12 and the streak-like projection 13 can be continuously formed in the lance cut metal 11. it can. In the final forming step by the progressive die press forming machine T, the streak-like recess 12 and the streak-like protrusion 13 are formed while the lance cut metal 11 is compressed by the lower die SG and the punch P. Thereby, it is possible to effectively prevent the corner portions of the streak-like recesses 12 and the streak-like projections 13 bent at a substantially right angle from being excessively extended (pulled). Therefore, also in the second modified example, similarly to the above-described embodiment, even a thin material that has undergone work hardening, that is, the lance cut metal 11, is prevented from being cracked or broken, and is favorably bent. be able to. Further, when the progressive press molding machine T is used in the final forming step, the streak-like recess 12 and the streak-like projection can also be obtained by feeding the lance cut metal 11 in the direction indicated by the arrow in FIG. It is possible to prevent cracks and breakage by suppressing the elongation of the corner portion in the molding of the portion 13.

  Further, in the second modified example, the streak-like recess 12 and the streak-like projection 13 are finally formed on the lance cut metal 11 using the progressive press molding machine T. The shaped recess 12 and the streaky projection 13 can be finally formed. In this case, as described in the first modification, the expanded metal 14 is preformed in a direction substantially orthogonal to the rolling direction. Then, by continuously supplying the preformed expanded metal 14 to the progressive press molding machine T, the streak-like recess 12 and the streak-like projection 13 are continuously formed on the expanded metal 14 as described above. Is done. Therefore, the streak-like recess 12 and the streak-like projection 13 can be formed well without causing cracks or breakage to the expanded metal 14.

  Further, the present invention is not limited to the above embodiment and each modification, and various modifications can be made. For example, in the said embodiment and each modification, although the streaky recessed part 12 and the streaky convex part 13 were shape | molded in the whole width direction of the lance cut metal 11 and the expanded metal 14, the lance cut metal cut out to the predetermined magnitude | size It is also possible to form the streak-like recess 12 or the streak-like projection 13 only at the substantially central portion of the 11 or the expanded metal 14. Also in this case, the corrugated shape of the preformed dimension can be formed in the preforming step, and then the streak-like concave portion 12 and the streaky convex portion 13 can be formed while being compressed in the final forming step. At this time, in the lance cut metal 11 or the expanded metal 14, the boundary portion between the corrugated shape, the substantially central portion where the streak-like concave portion 12 and the streaky convex portion 13 are formed, and the peripheral portion where the flat shape is maintained is Since the final molding is performed while being compressed after being gently deformed by the preliminary molding, the elongation due to bending is suppressed even at the boundary portion. Therefore, even when the streak-like recess 12 or the streak-like projection 13 is formed on a part of the lance cut metal 11 or the expanded metal 14, the streak-like unevenness forming method according to the present invention generates cracks or breaks. Can be molded well.

  Furthermore, for example, regarding the manufacture of the lance cut metal 11 and the expanded metal 14 described above, the lance cut metal 11 and the expanded metal 14 can be manufactured by a process other than the manufacturing process described above. Moreover, although it implemented using the corrugated molding machine K and the press molding machine O in the preforming process and final molding process mentioned above, it can preform and compress so that a preforming dimension may become larger than a final molding dimension. However, as long as final molding with the final molding dimension is possible, molding using other apparatuses is also possible. Also in this case, the same effects as those of the above-described embodiment and each modification can be expected.

It is the schematic which shows the flow-path formation member of the separator for fuel cells manufactured by the streak uneven | corrugated shaping | molding method which concerns on embodiment of this invention. (A), (b) is a figure for demonstrating the lance cut metal which forms the flow-path formation member of FIG. (A), (b) is a figure for demonstrating the lance cut manufacturing process which manufactures the lance cut metal of FIG. It is a figure for demonstrating the preforming which shape | molds a waveform shape in the lance cut metal of FIG. (A), (b) is a figure for demonstrating the waveform shape shape | molded by preforming. (A) is the schematic for demonstrating a last shaping | molding process, (b) is a figure for demonstrating the streaky recessed part and streaky convex part shape | molded by final shaping | molding. 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. (A), (b) is a figure for demonstrating the expanded metal which concerns on the 1st modification of this invention. It is a figure for demonstrating the rolling process which manufactures the expanded metal of FIG. (A)-(c) is a figure for demonstrating the final shaping | molding process which concerns on 2nd Embodiment of this invention, and finally shape | molds a stripe-shaped recessed part and a stripe-shaped convex part continuously.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Channel formation member, 11 ... Lance cut metal, 11a ... Bond part, 12 ... Streaky recessed part, 13 ... Streaky convex part, 14 ... Expanded metal, 14a ... Bond part, 20 ... Metal thin plate, 30 ... Resin frame 40 ... MEA, R ... lance cut metal processing device, K ... corrugating machine, O ... press molding machine, A ... rolling molding machine, T ... progressive press molding machine

Claims (11)

A streak uneven molding method for forming a plurality of streak recesses and streak protrusions on a thin material in which a large number of through holes are formed in a mesh shape,
Waveform shape consisting of a plurality of recesses and projections with respect to the thin material is preformed with a preforming dimension larger than the final molding dimension of the plurality of stripe-like recesses and stripe-shaped projections,
A streak characterized in that the plurality of streak-shaped concave portions or streaky convex portions are finally molded by being deformed while being compressed until the preformed dimensions of the pre-shaped corrugated concave portion and convex portion become the final molding size. -Shaped uneven forming method.   2. The streak uneven forming method according to claim 1, wherein the thin material is a lance 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. The thin-walled material is a thin-walled material that has been rolled after a large number of through-holes are formed in a mesh shape,
The streak uneven forming method according to claim 1, wherein the corrugated shape is preformed in a direction different from the direction in which the thin material is rolled.   4. The streaks according to claim 3, wherein the thin-walled material is an expanded metal formed in a substantially flat plate shape by rolling after forming a large number of through holes in a mesh shape by a shear bending process on a flat metal sheet. -Shaped uneven forming method. The preliminary molding dimensions and the final molding dimensions of the final molding are:
The streak-like unevenness forming method according to claim 1, wherein the plurality of streak-like recesses or streak-like protrusions have dimensions in the unevenness forming direction. The preforming continuously forms the corrugated shape with respect to the thin material,
The said final shaping | molding deform | transforms the waveform shape continuously shape | molded by the said preforming, compressing continuously, and shape | molds the said streaky recessed part and a streaky convex part. The method for forming streak unevenness according to any one of the above. In a metal separator for a fuel cell that forms a gas flow path for supplying a fuel gas and an oxidant gas to the electrode layer constituting the electrode structure of the fuel cell,
The gas flow path of the metal separator is composed of a plurality of streaky concave portions and streaky convex portions formed on a thin material in which a large number of through holes are formed in a mesh shape,
The plurality of streaky concave portions and streaky convex portions are:
Waveform shape consisting of a plurality of recesses and projections with respect to the thin material is preformed with a preforming dimension larger than the final molding dimension of the plurality of stripe-like recesses and stripe-shaped projections,
A metal separator for a fuel cell, wherein the preformed corrugated recesses and projections are deformed while being compressed until the preformed dimensions of the projecting parts become the final molded dimensions.   8. The metal separator for a fuel cell according to claim 7, wherein the thin material is a lance 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. The thin-walled material is a thin-walled material that has been rolled after a large number of through-holes are formed in a mesh shape,
The metal separator for a fuel cell according to claim 7, wherein the corrugated shape is preformed in a direction different from the direction in which the thin material is rolled.   10. The fuel according to claim 9, wherein the thin material is an expanded metal formed into a substantially flat plate shape by rolling a plurality of through holes formed into a mesh shape by a shear bending process on a flat metal sheet. Metal separator for batteries. The preforming dimensions and the final molding dimensions are:
The metal separator for a fuel cell according to claim 7, which is a dimension of the plurality of streak-like concave portions or the streaky convex portions in the concave-convex forming direction.

Images