JP2008287955A - Fuel cell separator and forming method of gas diffusion member to constitute fuel cell separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell separator which improves power generation efficiency of a fuel cell by reducing exhaust amount of a non-reaction gas while securing excellent gas circulation, and a forming method of a gas diffusion member. <P>SOLUTION: The separator 10 is constructed of a separator main body 11 and a collector 12 as a gas diffusion member. The main body 11 prevents mixing of a fuel gas and an oxidizer gas. The collector 12 has a first through hole group in which through holes formed in mesh-shape and step-wise are arranged in a first direction and a second through hole group arranged in a second direction different from the first direction. By this structure, excellent circulation of the introduced gas can be secured. Further, the introduced gas can be meandered by circulating it in the gas passage formed by the first through hole group and the second through hole group. Thereby, the introduced gas can be supplied excellently to an MEA 30 and power generation efficiency of the fuel cell can be improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell separator, and more particularly to a fuel cell separator employed in a polymer electrolyte fuel cell and a method for forming a gas diffusion member constituting the fuel cell separator.

  A polymer electrolyte fuel cell generally includes a membrane-electrode assembly including an anode electrode layer formed on one side of an electrolyte membrane and a cathode electrode layer formed on the other side. In the polymer electrolyte fuel cell, fuel gas (for example, hydrogen gas) and oxidant gas (for example, air) are supplied from the outside to the anode electrode layer and the cathode electrode layer, respectively. As a result, an electrode reaction occurs in the membrane-electrode assembly to generate power. For this reason, in order to improve the power generation efficiency of the polymer electrolyte fuel cell, it is important to efficiently supply the fuel gas and the oxidant gas necessary for the electrode reaction to the membrane-electrode assembly.

  Here, in the polymer electrolyte fuel cell, the fuel gas and the oxidant gas supplied from the outside are separately supplied to the anode electrode layer and the cathode electrode layer, and power is generated by a membrane-electrode reaction. A separator is provided for outputting the generated electricity to the outside. Conventionally, in order to improve the power generation efficiency of the polymer electrolyte fuel cell, it has been proposed to improve the gas supply efficiency of supplying the fuel gas or oxidant gas in the separator to the anode electrode layer or the cathode electrode layer. Yes.

  For example, the following Patent Document 1 discloses a fuel cell that employs a separator composed of a thin flat plate-like substrate and a net-like conductor. The mesh-like conductor in this conventional fuel cell is formed of, for example, expanded metal or metal lath having diamond-shaped slits, and the flow direction of fuel gas or air (oxidant gas) introduced from the outside A plurality of gas flow paths having a substantially rectangular cross-sectional shape formed in a rectangular shape are formed. And in this conventional fuel cell, the fuel gas or the oxidant gas introduced from the outside is circulated in the gas flow path formed in a substantially rectangular shape, through the mesh formed in the conductor, These gases can be supplied to the anode electrode layer or the cathode electrode layer of the membrane-electrode assembly, thereby improving the gas supply efficiency.

Further, for example, Patent Document 2 below discloses a fuel cell separator that can improve the gas supply function of the separator. The fuel cell separator includes a flat plate-like first member (carbon) and a plurality of projecting pieces stacked on the first member and elastically contacting the anode electrode layer and the cathode electrode layer and forming a gas flow path. It is comprised from the 2nd member (metal plate) in which was formed. In this conventional fuel cell separator, the turbulent flow is generated by passing through the gas flow path formed by the plurality of projecting pieces of the second member, and the fuel gas or oxidant gas supplied from the outside Is allowed to pass three-dimensionally in all directions. As a result, the fuel gas and the oxidant gas can be diffused satisfactorily, and the gas supply efficiency to the anode electrode layer and the cathode electrode layer is enhanced.
JP 2005-209470 A JP 2002-184422 A

  As described above, the mesh-like conductor in the fuel cell shown in Patent Document 1 and the second member in the fuel cell separator shown in Patent Document 2, that is, the gas diffusion member, were introduced from the outside. Fuel gas or oxidant gas can be diffused. Therefore, the gas supply efficiency to the anode electrode layer or the cathode electrode layer can be improved.

  However, in the mesh-like conductor shown in Patent Document 1 and the second member shown in Patent Document 2, the gas flow formed by the gas flow path and the projecting piece formed in a substantially rectangular cross section. For example, the path may be substantially parallel to the direction connecting the inlet for introducing the fuel gas and the oxidant gas into the interior and the outlet for leading the introduced gas to the outside. For this reason, the gas inlet formed and the outlet can be in a linear communication state by the formed gas flow path. In this state, when the introduced fuel gas and oxidant gas are passed through the gas flow path, a part of the gas flow is diffused by the meshes or protrusions formed on the conductor, and the anode electrode layer and the cathode electrode Although it is consumed by the layer, the other part is not diffused, in other words, may be discharged outside without being consumed by the anode electrode layer and the cathode electrode layer.

  Thus, in the situation where the fuel gas and the oxidant gas discharged without being consumed, that is, the unreacted gas increases, the power generation efficiency in the fuel cell cannot be improved. In other words, in order to improve the power generation efficiency in the fuel cell, it is necessary to supply the introduced fuel gas and oxidant gas to the anode electrode layer and the cathode electrode layer more efficiently and reduce the discharge amount of the unreacted gas. is there. Here, in the second member disclosed in Patent Document 2, for example, by adjusting the formation position of the projecting piece, the flow of the introduced fuel gas and oxidant gas is made more turbulent, and the anode It is considered possible to increase the gas supply amount to the electrode layer and the cathode electrode layer, that is, to reduce the discharge amount of unreacted gas.

  However, in this case, the flow resistance of the fuel gas and the oxidant gas that circulates in the gas flow path, in other words, the pressure loss increases, which may hinder the introduction of new fuel gas and oxidant gas. There is sex. In this case, as a result, fuel gas and oxidant gas supplied to the anode electrode layer and the cathode electrode layer may be insufficient, and it becomes difficult to improve the power generation efficiency of the fuel cell.

  The present invention has been made to solve the above-described problems, and its object is to improve the power generation efficiency of a fuel cell by reducing the amount of unreacted gas discharged while ensuring good gas flowability. An object of the present invention is to provide a fuel cell separator and a method for forming a gas diffusion member constituting the fuel cell separator.

  In order to achieve the above object, a feature of the present invention is a fuel cell separator for supplying a fuel gas and an oxidant gas to an electrode layer constituting an electrode structure of a fuel cell, said fuel cell A flat separator body that separates gas and oxidant gas to prevent mixed flow; a first through hole group in which a plurality of through holes formed in a mesh shape and steps are arranged in a first direction; A plurality of through-holes formed in a step-like shape and in a second direction different from the first direction, and between the separator body and the electrode layer The gas flow path for supplying the fuel gas or the oxidant gas to the electrode layer is composed of a gas diffusion member formed by the first through hole group and the second through hole group.

  According to this, the fuel gas and the oxidant gas introduced from the outside are introduced between the separator body and the electrode layer while being prevented from being mixed by the separator body. Then, the introduced fuel gas and oxidant gas are supplied to the electrode layer through a gas flow path formed by the gas diffusion member. In this case, the gas flow path formed by the gas diffusion member is formed by the first through-hole group arranged in the first direction and the second through-hole group arranged in the second direction different from the first direction. The Thus, the introduced fuel gas and oxidant gas flow while meandering in the arrangement direction of the first through hole group and the second through hole group, that is, in the first direction and the second direction.

  As described above, the fuel gas and the oxidant gas flowing through the gas flow path are diffused by meandering in addition to the diffusion by passing through the formed through hole. Therefore, since the introduced gas can be diffused well, the fuel gas or the oxidant gas can be efficiently supplied to the electrode layer, and the electrode reaction in the electrode structure can be promoted. As a result, unreacted gas can be greatly reduced, and the power generation efficiency of the fuel cell can be improved.

  Moreover, each through-hole which forms a 1st through-hole group and a 2nd through-hole group is formed in mesh shape and step shape. Accordingly, the flow resistance (pressure loss) can be reduced by preferentially flowing through the through-hole portion where the introduced fuel gas and oxidant gas are formed stepwise. As a result, new fuel gas and oxidant gas can be easily introduced into the electrode layer from the outside, and as a result, the gas necessary for the electrode reaction in the electrode structure can be sufficiently supplied, and the fuel can be supplied. The power generation efficiency of the battery can be improved.

  Further, in this case, the first through hole group and the second through hole group formed in the gas diffusion member are sequentially arranged sequentially with respect to the flow direction of the fuel gas or the oxidant gas. Good. The gas diffusion member may include a plurality of the first through-hole groups arranged in parallel and a plurality of the second through-hole groups arranged in parallel. Furthermore, the gas diffusion member includes a first through-hole group forming region in which a plurality of the first through-hole groups are formed in parallel and a second through-hole group forming region in which a plurality of the second through-hole groups are formed in parallel. It is good to form from a metal lath that has been repeatedly formed.

  According to these, the 1st through-hole group and 2nd through-hole group which are formed in a gas diffusion member can be sequentially arrange | positioned sequentially (repetitively) with respect to the distribution direction of fuel gas or oxidant gas. That is, the 1st through-hole group and the 2nd through-hole group in a gas diffusion member are arrange | positioned in series like a 1st through-hole group, a 2nd through-hole group, a 1st through-hole group ..., for example. Can do. Thereby, the introduced fuel gas and oxidant gas can be meandered and diffused more favorably according to the number (number of repetitions) of the first through-hole group and the second through-hole group. Accordingly, the fuel gas or the oxidant gas can be more efficiently supplied to the electrode layer, whereby the electrode reaction in the electrode structure can be promoted. As a result, unreacted gas can be greatly reduced, and the power generation efficiency of the fuel cell can be improved.

  In addition, a plurality of first through hole groups and second through hole groups formed in the gas diffusion member can be arranged in parallel. Thereby, the number of gas flow paths through which the introduced fuel gas and oxidant gas flow can be increased, and the flow resistance (pressure loss) can be further reduced. Therefore, new fuel gas and oxidant gas can be easily introduced into the electrode layer from the outside, and as a result, the gas necessary for the electrode reaction in the electrode structure can be sufficiently supplied, and the fuel cell It is possible to improve the power generation efficiency.

  Further, the first through-hole group forming region in which a plurality of first through-hole groups are formed in parallel and the second through-hole group forming region in which a plurality of second through-hole groups are formed in parallel are sequentially formed as gas diffusion members. The metal lath can be molded. Thereby, the 1st through-hole group and 2nd through-hole group which are formed in a gas diffusion member can be arranged sequentially (repetitively) sequentially with respect to the distribution direction of fuel gas or oxidant gas, The number of gas flow paths through which the introduced fuel gas and oxidant gas flow can be increased. Accordingly, the fuel gas and the oxidant gas can be favorably diffused, the flow resistance (pressure loss) can be suppressed, and the fuel gas or the oxidant gas can be more efficiently supplied to the electrode layer. As a result, the electrode reaction in the electrode structure can be promoted, unreacted gas can be greatly reduced, and the power generation efficiency of the fuel cell can be improved.

  Another feature of the present invention is that the gas diffusion member forming method for the fuel cell separator described above includes a fixed mold for placing a thin plate material, and a feeding direction of the thin plate material with respect to the fixed mold. It uses a molding apparatus that is arranged and moves in the plate thickness direction of the thin plate material and moves in the plate width direction of the thin plate material, and forms a through hole by shearing the thin plate material. A processing cycle in which the thin plate material is fed by a predetermined processing length, the shear mold is moved in the thickness direction of the thin plate material and retracted to form a through-hole, and the shear mold is formed into the thin plate A first step of forming the first through hole group by executing each of a plurality of preset processing positions in one direction in the plate width direction of the material, and after the first step, the thin plate material is predetermined For machining length A processing cycle for forming a through hole by moving and retracting the shearing die with respect to the thickness direction of the thin plate material to form a through hole is set in advance in the other direction in the plate width direction of the thin plate material. And a second step of forming the second through-hole group by executing each of the plurality of machining positions.

  In this case, in the second step, the last machining position among the plurality of preset machining positions in the first step is set as the plurality of preset machining positions in the second step. The machining cycle may be executed as the first machining position. In addition, the first step and the second step may be sequentially repeated. Furthermore, in this case, the shearing die preferably has a plurality of shearing blades formed at a predetermined interval, and the shearing blade has a trapezoidal shape or a triangular shape in cross section perpendicular to the feeding direction of the thin plate material. It is good to be.

  According to these, it is not necessary to use a special processing apparatus separately, and the equipment cost can be reduced. And in the 1st process and the 2nd process, since the processing cycle which forms a penetration hole for every plurality of processing positions can be performed, the 1st penetration hole group and the 2nd penetration hole group of a gas diffusion member are easy. Can be formed. In addition, since the first machining position in the second step can be matched with the last machining position in the first step, the fuel gas or the oxidant gas into which the first through hole group and the second through hole group are introduced. It can arrange | position in series with respect to the distribution direction. In addition, since the first step and the second step can be sequentially repeated, the number of arrangement of the first through hole group and the second through hole group can be easily changed. Further, since the shear type shear blade can be formed into a plurality of trapezoidal shapes or triangular shapes, a plurality of first through hole groups and second through hole groups can be easily formed in parallel.

  Further, the machining cycle in the first step is repeatedly executed for each of the preset machining positions, and the machining cycle in the second step is repeatedly executed for each of the preset machining positions. It is good to do.

  According to this, it is possible to increase the thickness of the portion where the shape of the shear type shearing blade is transferred, that is, the stepped portion, by executing the processing cycle of forming the through hole a plurality of times at the same processing position. it can. Therefore, by configuring the fuel cell separator using the gas diffusion member formed in this way, the flow resistance (pressure loss) when conducting the fuel gas or oxidant gas can be reduced, and the electrode layer The fuel gas or oxidant gas necessary for the electrode reaction can be sufficiently supplied.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a part of a polymer electrolyte fuel cell stack configured using a fuel cell separator 10 (hereinafter simply referred to as a separator 10) according to an embodiment of the present invention. is there. The fuel cell stack is formed by laminating a large number of single cells composed of two separators 10 and a frame 20 and a MEA 30 (Membrane-Electrode Assembly) disposed between the separators 10 and stacked. The

  For each unit cell, for example, when a fuel gas such as hydrogen gas and an oxidant gas such as air are introduced from the outside of the fuel cell stack, an electrode reaction occurs in the MEA 30 as an electrode structure. Is generated by. Here, in the present specification, in the following description, the fuel gas and the oxidant gas are collectively referred to simply as gas.

  As shown in FIG. 1, the separator 10 has a separator main body 11 that prevents a mixed flow of gas introduced into the fuel cell stack, and gas supplied from the outside uniformly diffuses into the MEA 30 and generates power by an electrode reaction. And a collector 12 as a gas diffusion member for collecting the generated electricity.

  The separator body 11 is formed from a metal thin plate (for example, a stainless plate having a thickness of about 0.1 mm) as a material. In addition, as a raw material which forms the separator main body 11, the steel plate etc. which gave anti-corrosion processing, such as gold plating, etc. can be employ | adopted elsewhere, for example. Moreover, it can replace with forming the separator main body 11 from a metal thin plate, and can also form a nonmetallic material (for example, carbon etc.) which has electroconductivity as a raw material.

  As shown in FIG. 2, the separator body 11 is formed in a substantially square flat plate shape, and a gas inlet 11a and a gas outlet 11b opposed to the gas inlet 11a are formed at the peripheral portion thereof. Two pairs consisting of are formed. Each pair is formed so as to be substantially orthogonal to each other.

  The gas inlet 11a is formed in a substantially elliptical through hole, and introduces fuel gas or oxidant gas supplied from the outside of the fuel cell stack into the single cell, and other stacked single cells. The fuel gas or oxidant gas supplied to the gas is circulated. The gas outlet 11b is also formed in a substantially elliptical through-hole, out of the gas introduced into the single cell, the unreacted gas is discharged to the outside by the MEA 30, and other stacked single cells. Circulate unreacted gas from

  As shown in FIG. 3A, the collector 12 is formed from a metal thin plate (hereinafter, this metal thin plate is referred to as a metal lath MR) in which a large number of small-diameter through holes are formed in a mesh shape and stepped shape. Is done. Here, the metal lath MR is formed from a thin plate material (for example, stainless steel) having a plate thickness of about 0.1 mm, for example, and the diameter of the through holes formed is about 0.1 mm to 1 mm. ing. Further, as shown in FIG. 3B, the metal lath MR is connected so that the portions where the mesh-shaped through holes are formed sequentially overlap as shown in the side view in the left-right direction in FIG. Hereinafter, this connecting portion is referred to as a bond portion), and its cross-sectional shape is a staircase shape. And this metal lath MR is manufactured through the metal lath shaping | molding process as a shaping | molding method of the gas diffusion member which comprises the separator for fuel cells so that it may demonstrate below.

  In the metal lath forming step, a large number of mesh-like through holes are formed in a stepped shape in the stainless steel plate S using a metal lath processing apparatus R schematically shown in FIG. The metal lath processing apparatus R includes a feed roller OR for sequentially feeding and supplying the stainless steel plate S, a presser mechanism OK for appropriately fixing the stainless steel plate S at the time of processing, and a mesh-like shape by sequentially shearing the stainless steel plate S. And a blade die H for forming the 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.

  The blade mold H is fixed to a base (not shown) and has a lower blade SH as a fixed mold on which the stainless steel plate S is placed, the thickness direction of the stainless steel plate S (the vertical direction in FIG. 4A), and stainless steel. It consists of an upper blade UH as a shear type that can move in the plate width direction of the plate S (perpendicular to the paper surface in FIG. 4A). And as shown in FIG.4 (b), in order to fix the stainless steel board S appropriately between the lower blades SH, the upper surface has a planar shape. The upper blade UH is movable in the plate thickness direction and plate width direction of the stainless steel plate S by an AC servo mechanism (not shown). The blade shape of the upper blade UH is a plurality of substantially trapezoidal shapes formed at predetermined intervals in order to form a cut line on the stainless steel plate S by shearing and to form a through hole by stretching. Yes.

  The metal lath forming process using the metal lath processing apparatus configured as described above is composed of two processes, a first process and a second process. That is, in the first step, the upper blade UH moves at a predetermined interval in one direction in the plate width direction of the stainless steel plate S, and the stainless steel plate S is moved in the first direction as shown in FIG. This is a step of forming through holes to be arranged (hereinafter referred to as a first through hole group). In the following description, a region where the first through hole group is formed is referred to as a first through hole group forming region. Further, in the second step, the upper blade UH moves at a predetermined interval in the plate width direction of the stainless steel plate S in the direction opposite to the first step, and as shown in FIG. This is a step of forming through holes arranged in the second direction (hereinafter referred to as a second through hole group). In the following description, a region where the second through-hole group is formed is referred to as a second through-hole group forming region. Hereinafter, this metal lath forming process will be described in detail with reference to FIGS.

  First, in the first step, as shown in FIG. 5A, the stainless steel plate S is fed to the blade mold H by a predetermined machining length by the feed roller OR while the upper blade UH is in the initial machining position. As shown in FIG. 5B, the upper blade UH descends in the direction of the lower blade SH, that is, in the plate thickness direction of the stainless steel plate S, and shears the stainless steel plate S by the substantially trapezoidal shape portion together with the lower blade SH. And cut the cut. 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 thereafter, as shown in FIG. Return until. Thus, by executing the machining cycle shown in FIGS. 5A to 5C, the state in which the blade shape of the upper blade UH is transferred to the machining portion corresponding to the initial machining position of the stainless steel plate S and Become.

  Next, the upper blade UH moves from the returned initial machining position to the first machining position set at a position separated by a predetermined interval on the right side in the plate width direction of the stainless steel plate S in FIG. Here, the interval between the machining positions in the following description, that is, the movement distance of the upper blade UH, is set to, for example, about 1/4 of the blade length WH of the upper blade UH shown in FIG.

  Then, as shown in FIG. 6A, the stainless steel plate S is fed to the blade mold H by a predetermined processing length by the feed roller OR while the upper blade UH is moved to the first processing position. Next, as shown in FIGS. 6B and 6C, the upper blade UH descends in the direction of the lower blade SH to process a cut in the stainless steel plate S and descends to the lowest point position to move the stainless steel plate S. Then, as shown in FIG. 6 (a), it returns to the first processing position. Thus, the state in which the blade shape of the upper blade UH is transferred to the machining portion corresponding to the first machining position of the stainless steel plate S by executing the machining cycle shown in FIGS. 6 (a) to 6 (c). It becomes.

  Next, the upper blade UH is positioned at a predetermined distance (about ¼ of the blade length WH of the upper blade UH) on the right side in the plate width direction of the stainless steel plate S in FIG. 6 from the returned first processing position. Move to the set second machining position. And in this 2nd process position, a process cycle is performed with respect to the stainless steel plate S similarly to the process in the 1st process position mentioned above. Thereby, the blade shape of the upper blade UH is transferred to the processing portion corresponding to the second processing position of the stainless steel plate S.

  Further, the upper blade UH is set at a position separated from the restored second machining position by a predetermined interval (about ¼ of the blade length WH of the upper blade UH) on the right side in the plate width direction of the stainless steel plate S in FIG. Move to the third machining position. And also in this 3rd process position, a process cycle is performed with respect to the stainless steel plate S similarly to the process in the 1st process position mentioned above. Thereby, the blade shape of the upper blade UH is transferred to the processing portion corresponding to the third processing position of the stainless steel plate S.

  Thus, in the first step, the upper blade UH moves to the initial machining position, the first machining position, the second machining position, and the third machining position, and executes a machining cycle on the stainless steel plate S. And if the 1st penetration hole group formation field is formed, the 2nd process will be performed continuously. Hereinafter, this second step will be described.

  In the second step, the third processing position (last processing position) in the first step is set as the initial processing position in the second step. Then, as shown in FIG. 7A, the upper blade UH is set at a position separated from the initial processing position by a predetermined interval on the left side in the plate width direction of the stainless steel plate S in FIG. Move to the first machining position. Also in this second step, the interval between the machining positions is set to about ¼ of the blade length WH of the upper blade UH, for example.

  Then, in a state where the upper blade UH is in the first processing position, the stainless steel plate S is fed to the blade mold H by a predetermined processing length by the feed roller OR. Then, as shown in FIG. 7B, the upper blade UH descends in the direction of the lower blade SH, that is, in the plate thickness direction of the stainless steel plate S, and shears the stainless steel plate S by the substantially trapezoidal shape portion together with the lower blade SH. And cut the cut. Subsequently, the upper blade UH is lowered to the lowest point position, and the stainless steel plate S in contact with the blade of the upper blade UH is bent and extended downward, and then, as shown in FIG. Return to the first machining position. Thus, by executing the machining cycle shown in FIGS. 7A to 7C, the blade shape of the upper blade UH is formed on the machining portion corresponding to the first machining position in the second step of the stainless steel plate S. It is in a transcribed state.

  Next, the upper blade UH is a predetermined interval (about ¼ of the blade length WH of the upper blade UH) on the left side in the plate width direction of the stainless steel plate S in FIG. 7 from the first processing position of the returned second step. It moves to the 2nd processing position in the 2nd process set as a position apart.

  Then, as shown in FIG. 8A, the stainless steel plate S is fed to the blade mold H by a predetermined processing length by the feed roller OR while the upper blade UH is moved to the second processing position. Next, as shown in FIGS. 8B and 8C, the upper blade UH descends in the direction of the lower blade SH to process a cut in the stainless steel plate S and descends to the lowest point position to move the stainless steel plate S. Then, as shown in FIG. 8A, the process returns to the second processing position in the second step. Thus, by executing the machining cycle shown in FIGS. 8A to 8C, the blade shape of the upper blade UH is formed on the machining portion corresponding to the second machining position in the second step of the stainless steel plate S. It is in a transcribed state.

  Next, the upper blade UH is a predetermined interval (about ¼ of the blade length WH of the upper blade UH) on the left side in the plate width direction of the stainless steel plate S in FIG. 8 from the second processing position of the returned second step. Move to the third machining position in the second step set at a distant position. And in this 3rd processing position, a processing cycle is performed to stainless steel board S like processing in the 2nd processing position mentioned above. Thereby, the blade shape of the upper blade UH is transferred to the processing portion corresponding to the third processing position in the second step of the stainless steel plate S.

  Thus, in the second step, when the upper blade UH is subjected to cut processing and bending extension processing on the stainless steel plate S at the third processing position, that is, the initial processing position in the first step, the upper blade UH is By sequentially moving from the first processing position to the third processing position in the first step, the cut and bending processes are performed on the stainless steel plate S. And the upper blade UH will move sequentially from the 1st process position of a 2nd process to the 3rd process position, and will perform with respect to the stainless steel plate S, if the cut process and bending extension process in the 3rd process position of a 1st process are performed. Perform cuts and bends. In this way, by repeatedly executing the first step and the second step, as shown in FIG. 3A, the first through-hole group forming region and the second through-hole group forming region are repeated. The formed metal lath MR is molded.

  The metal lath MR formed specifically will be described. Each through-hole formed in the first process from the initial machining position to the third machining position is in the right direction of the stainless steel plate S in FIGS. 3 and 5 to 8 ( A plurality of first through-hole groups are sequentially formed and arranged in the first direction). Moreover, each through-hole formed in the 2nd process from a 1st process position to a 3rd process position is shape | molded sequentially in the left direction (2nd direction) of the stainless steel plate S in FIG. 3 and FIGS. A plurality of second through hole groups arranged in a row are formed.

  More specifically, the metal lath MR formed by the metal lath forming step is a square having a size substantially the same as the size of the anode electrode layer AE or the cathode electrode layer CE of the MEA 30 described later so as to have a predetermined product size. And is manufactured as a collector 12.

  The collector 12 manufactured in this way is integrally fixed to the separator body 11 to form the separator 10. The fixing of the collector 12 will be briefly described below. The collector 12 is disposed at a substantially central portion of the separator body 11. And the contact part of the separator main body 11 and the collector 12 is metal-bonded by the brazing method, for example, and is integrally fixed.

  More specifically, first, a paste-like brazing material such as copper or nickel is applied to the collector 12. And the collector 12 which apply | coated the brazing material is temporarily fixed to the predetermined position of the separator main body 11. FIG. At this time, in the collector 12, the arrangement direction of the pair of gas inlets 11 a and gas outlets 11 b formed in the separator body 11 coincides with the opening direction of the through holes in the collector 12 (more specifically, the metal lath MR). Is temporarily fixed. Next, the temporarily fixed separator body 11 and collector 12 are heated at a predetermined temperature for a predetermined time in a reducing gas atmosphere, and then cooled. Thereby, the separator main body 11 and the collector 12 are joined metallically and fixed integrally.

  Here, the joining method for metallicly joining the separator body 11 and the collector 12 is not limited to the brazing method described above. That is, other methods that can metallically join the separator body 11 and the collector 12, for example, a welding method or a diffusion bonding method can be employed.

  As shown in FIG. 9, the frame 20 is composed of a pair of two resin plate bodies 21 and 22 having the same structure, and each of the two separators 10 (more specifically, the separator body 11) has its own structure. One side is fixed. The resin plate main bodies 21 and 22 have substantially the same external dimensions as the separator main body 11 and have a thickness slightly smaller than the molding height of the collector 12, that is, the metal lath MR. And with respect to the resin plate main body 21, the resin plate main body 22 rotates and arrange | positions about 90 degree | times in the same plane direction, and is laminated | stacked. The resin plate bodies 21 and 22 can employ various resin materials, and preferably glass epoxy resins.

  Further, the resin plate main bodies 21 and 22 have the same peripheral edge portions as the positions corresponding to the through holes of the gas inlet 11a and the gas outlet 11b formed in the separator main body 11 in a state where a single cell is formed. Through holes 21a and 21b and through holes 22a and 22b having substantially the same shape as each through hole are formed. The resin plate main bodies 21 and 22 are provided with receiving holes 21c and 22c for receiving the collector 12 joined to the separator main body 11 at substantially the center part thereof. The accommodating holes 21c and 22c are formed through a pair of gas inlet 11a and gas outlet 11b formed in the separator body 11 to be fixed, and the other resin plate body 21 or resin plate body 22 stacked. It is formed so as to accommodate the holes 21a, 21b or the through holes 22a, 22b.

  Thus, by forming the accommodation holes 21c and 22c, the lower surface (or upper surface) of the separator body 11 to be fixed, the inner peripheral surface of the accommodation hole 21c (or accommodation hole 22c), and the upper surface (or lower surface) of the MEA 30. A space (hereinafter, this space is referred to as a gas conduction space) is formed. For example, the fuel gas can be introduced into the gas conduction space from one gas introduction port 11a, and the oxidant gas can be introduced from the other gas introduction port 11a and the through hole 21a. Further, the unreacted gas that has passed through the gas conduction space can be led out to the outside through one gas outlet 11b and through the other gas outlet 11b and the through hole 21b.

  As shown in FIGS. 1 and 9, the MEA 30 is formed by laminating an electrolyte membrane EF and a predetermined catalyst on the electrolyte membrane EF in a layered manner, and on the gas conduction space side where fuel gas is introduced. The anode electrode layer AE to be arranged and the cathode electrode layer CE to be arranged on the gas conduction space side where the oxidant gas is introduced are used as main components. Note that the operation (electrode reaction) of the electrolyte membrane EF, the anode electrode layer AE, and the cathode electrode layer CE is not directly related to the present invention, and thus detailed description thereof is omitted.

  The electrolyte membrane EF is larger than the substantially square opening formed when the resin plate main bodies 21 and 22 of the frame 20 are laminated, and the through holes 21a and 21a are formed in a state where the resin plate main bodies 21 and 22 are laminated. 21b and the through holes 22a and 22b are formed in such a size that they are not blocked. Thus, by forming the electrolyte membrane EF, the gas introduced into the gas conduction space is prevented from leaking into the gas conduction space formed on the other side (so-called cross leak). The anode electrode layer AE and the cathode electrode layer CE as electrode layers are slightly smaller in outer dimensions than the substantially square opening formed when the resin plate bodies 21 and 22 of the frame 20 are laminated. It is said that.

  In addition, the anode electrode layer AE and the cathode electrode layer CE are configured such that the respective surface sides are covered with carbon cloth CC formed of conductive fibers. The carbon cloth CC uniformly supplies fuel gas or oxidant gas supplied into the gas conduction space to each electrode layer, and efficiently supplies electricity generated by the electrode reaction to the collector 12. To do. That is, since the carbon cloth CC is fibrous, the supplied gas is more uniformly diffused by conducting between the fibers. In addition, since the carbon cloth CC has conductivity, the generated electricity can be efficiently flowed to the collector 12. If necessary, the carbon cloth CC can be omitted.

  And a single cell is formed by laminating | stacking the separator main body 11, the collector 12, the flame | frame 20, and MEA30 one by one. Specifically, as shown in FIG. 9, the MEA 30 is disposed between the upper and lower two frames 20 that are disposed by being rotated approximately 90 degrees in the same plane, and, for example, an adhesive is applied. Accordingly, the electrolyte membrane EF of the MEA 30 is sandwiched between the frames 20 and is integrally fixed.

  The collector 12 is accommodated in the accommodating holes 21c and 22c of each frame 20 with respect to the integrally fixed frame 20 and MEA 30. At this time, the collector 12 includes the arrangement direction of the pair of gas inlets 11a and the gas outlets 11b formed in the frame 20 to be accommodated, that is, the flow direction of the introduced gas, and the collector 12 (more specifically, the metal lath MR). Are accommodated in the accommodation holes 21c and 22c of the frame 20 so that the opening directions of the through holes coincide with each other.

  Then, in a state where the collector 12 is accommodated in the accommodation holes 21 c and 22 c of the frame 20, for example, an adhesive or the like is applied to fix the separator body 11 to the frame 20 integrally. At this time, since the plate thickness of the resin plate main bodies 21 and 22 is slightly smaller than the molding height of the collector 12, the collector 12 is assembled in a state of being slightly pressed by the separator main body 11 toward the MEA 30 side. Thereby, the contact state between the collector 12 and the MEA 30 (more specifically, the carbon cloth CC) can be kept good. And the single cell formed in this way constitutes a fuel cell stack by laminating a plurality according to demand output.

  In the fuel cell stack configured as described above, as shown in FIG. 1, the gas inlets 11 a and the gas outlets 11 b of the separator body 11 are connected to the through holes 21 a and 21 b of the frame 20 between the stacked single cells. And it will be in the state which all communicated through the through-holes 22a and 22b. For this reason, in the following description in the present specification, the gas supply inner manifold, the gas outlet 11b, and the frame 20 are connected to the communication path formed by the gas inlet 11a of each single cell and the through holes 21a and 22a of the frame 20. The communication passage formed by the through holes 21b and 22b is referred to as a gas discharge inner manifold.

  When fuel gas or oxidant gas is supplied from the outside via the gas supply inner manifold, the supplied fuel gas or oxidant gas is introduced into the gas conduction space. The thus introduced fuel gas or oxidant gas is diffused uniformly in the gas conduction space by the collector 12 and is conducted.

  More specifically, the gas introduced into the gas conduction space from the gas supply inner manifold flows toward the gas discharge inner manifold while being in contact with the collector 12 disposed in the gas conduction space. Here, the collector 12 is arranged with a first angle with respect to the arrangement direction of the gas supply inner manifold (that is, the gas inlet 11a) and the gas discharge inner manifold (that is, the gas outlet 11b). The metal lath MR has a through-hole group and a second through-hole group arranged with a second angle.

  For this reason, a part of the gas introduced into the gas conduction space from the gas supply inner manifold is electrically connected to the bond portion of the collector 12 (metal lath MR). However, as shown schematically in FIG. The gas flow path formed by the first through hole group and the second through hole group is conducted. As a result, the gas introduced into the gas conduction space snakes and circulates toward the gas discharge inner manifold while colliding with the side wall surface of each through hole forming the first through hole group and the second through hole group. To do.

  And since the gas meanders and circulates in this way, the gas flow in the gas conduction space becomes a turbulent flow. Therefore, the gas introduced into the gas conduction space is uniformly diffused in the space, in other words, the gas concentration gradient is made uniform. In this way, the gas concentration gradient in the gas conduction space is made uniform, and further, when the gas passes through the carbon cloth CC, the fuel gas or the oxidant gas is supplied to the anode electrode layer AE and the cathode electrode layer CE. Evenly supplied.

  As a result, the electrode reaction region in the MEA 30 is the entire surface of the formed anode electrode layer AE and cathode electrode layer CE. As a result, by increasing the effective electrode reaction region, the electrode reaction efficiency can be greatly improved by efficiently performing an electrode reaction with the fuel gas or the oxidant gas supplied to the anode electrode layer AE and the cathode electrode layer CE. it can. And since the gas supplied with improving electrode reaction efficiency can be consumed effectively, unreacted gas can be reduced significantly. Therefore, the fuel cell can generate electricity efficiently.

  On the other hand, when the reaction efficiency of the electrode reaction in the anode electrode layer AE and the cathode electrode layer CE is improved, electricity is efficiently generated by the MEA 30. The generated electricity is taken out of the fuel cell through the collector 12 and the separator body 11. At this time, since a large number of mesh-like through holes are formed in the collector 12, the surface area per unit volume, that is, the contact area with the MEA 30 (more specifically, the carbon cloth CC) increases. Thus, by increasing the contact area with the MEA 30, the resistance (current collection resistance) when collecting the electricity generated by the MEA 30 can be extremely reduced. Thereby, the generated electricity can be collected efficiently, in other words, the current collection efficiency can be improved.

  As can be understood from the above description, according to this embodiment, gas from the outside of the fuel cell stack is prevented from being mixed by the separator body 11, and the separator body 11 and the MEA 30 (more specifically, the anode electrode AE or Between the cathode electrode CE). The introduced fuel gas and oxidant gas are supplied to the anode electrode AE and the cathode electrode CE via the gas flow path formed by the collector 12. In this case, the gas flow path formed by the collector 12 is formed by a first through hole group arranged in the first direction and a second through hole group arranged in a second direction different from the first direction. . Thus, the introduced fuel gas and oxidant gas flow while meandering in the arrangement direction of the first through hole group and the second through hole group, that is, in the first direction and the second direction.

  As described above, the fuel gas and the oxidant gas flowing through the gas flow path are diffused by meandering in addition to the diffusion by passing through the formed through hole. Therefore, the fuel gas or the oxidant gas can be efficiently supplied to the anode electrode AE or the cathode electrode CE, so that the electrode reaction in the MEA 30 can be promoted. As a result, unreacted gas can be greatly reduced, and the power generation efficiency of the fuel cell can be improved.

  Moreover, each through-hole which forms a 1st through-hole group and a 2nd through-hole group is formed in mesh shape and step shape as shown in FIG. Accordingly, the flow resistance (pressure loss) can be reduced by preferentially flowing the introduced fuel gas and oxidant gas through the first through hole group and the second through hole group formed in a stepped shape. it can. As a result, new fuel gas and oxidant gas can be easily introduced into the MEA 30 from the outside of the fuel cell stack, and as a result, sufficient gas for electrode reaction in the MEA 30 can be supplied. The power generation efficiency of the fuel cell can be improved.

  Further, the collector 12 is formed by sequentially repeating a first through hole group forming region in which a plurality of first through hole groups are formed in parallel and a second through hole group forming region in which a plurality of second through hole groups are formed in parallel. It can be formed from a metal lath MR. Accordingly, the first through hole group and the second through hole group formed in the collector 12 can be sequentially (repetitively) arranged sequentially with respect to the flow direction of the fuel gas or the oxidant gas. It is possible to increase the number of gas flow paths through which the fuel gas and the oxidant gas that have been circulated. Therefore, the fuel gas and the oxidant gas can be diffused satisfactorily, the flow resistance can be suppressed, and the fuel gas or the oxidant gas can be supplied to the MEA 30 more efficiently. As a result, the electrode reaction in the MEA 30 can be promoted, the unreacted gas can be greatly reduced, and the power generation efficiency of the fuel cell can be improved.

  In the above embodiment, the metal lath MR is formed by executing the above-described processing cycle only once at each processing position in the first step and the second step of the metal lath forming step. In this case, the metal lath can be formed by executing a plurality of machining cycles at each machining position. Hereinafter, although this modification is demonstrated, the same code | symbol is attached | subjected to the same part as the said embodiment, and the detailed description is abbreviate | omitted.

  Also in the metal lath forming process in this modified example, the first through-hole group forming region and the second through-hole group forming region are repeatedly formed on the stainless steel plate S using the metal lath processing apparatus R as in the above embodiment. However, in this modification, the machining cycle is executed twice at each machining position in the first process and the second process.

  Specifically, as in the above-described embodiment, the first machining cycle is first executed at the initial machining position. Next, the stainless steel plate S is again fed by a predetermined processing length by the feed roller OR to the blade mold H in which the upper blade UH has returned to the initial processing position. Then, the upper blade UH descends again toward the lower blade SH at the initial machining position to process the cut in the stainless steel plate S, and descends to the lowest point position to bend and extend the stainless steel plate S. Thus, by repeatedly executing the machining cycle, the blade shape is transferred to a position where the upper blade UH is displaced from the stainless steel plate S by a predetermined machining length at the initial machining position.

  Then, at each of the other machining positions in the first step and each machining position in the second step, as shown in FIG. 11, the staircase shape becomes 2 by executing the machining cycle twice as in the initial machining position. A metal lath MR ′ formed by transferring the blade shape twice is manufactured. In addition, although illustration is abbreviate | omitted, it cannot be overemphasized that the shape of the through-hole shape | molded in this modification becomes the same shape as the said embodiment. Further, in the following description, the number of executions of the machining cycle is not limited to twice, and it goes without saying that it can be executed three or more times.

  The collector 12 ′ molded using the metal lath MR ′ manufactured in this way has a larger plate thickness than the collector 12 in the above embodiment. Thereby, the inside of gas conduction space can be expanded and the flow path resistance of the gas at the time of conduction | electrical_connection can be reduced more. Furthermore, the flow resistance when the gas introduced into the gas conduction space passes through the first through hole group and the second through hole group can be reduced. As a result, the gas that conducts in the gas conduction space can be conducted smoothly, so that the reaction between the gas and the anode electrode layer AE and the cathode electrode layer CE can be promoted, and the power generation efficiency of the fuel cell is improved. Can be made. About the other effect, the effect similar to the said embodiment can be anticipated.

  In carrying out the present invention, the present invention is not limited to the above-described embodiments and modifications, and various modifications can be made.

  For example, in the above-described embodiment and modification, each machining position in the first process and the second process is set to four places including the initial machining position, but the number of machining positions set is limited to this. It is not a thing. That is, as long as the first through hole group and the second through hole group can be formed by executing the first step and the second step, any number of machining positions may be set.

  Moreover, in the said embodiment and modification, the blade shape of the upper blade UH of the metal lath processing apparatus R for shape | molding the metal lath MR and MR 'which forms the collectors 12 and 12' is made into the some shape formed by the predetermined space | interval. It was implemented as a substantially trapezoidal shape. However, for example, as shown in FIG. 12, the blade shape may be changed to an upper blade UH ′ having a substantially triangular cross section formed at a predetermined interval.

  Then, by adopting this modified upper blade UH 'and performing the metal lath forming step as in the above-described embodiment and modification, a metal lath MR "as shown in FIG. 13 can be manufactured. In this case, the distance between the machining positions in the first and second steps, that is, the movement distance of the upper blade UH ′ may be set to about ¼ of the formation interval of the substantially triangular blade, for example. Also in this case, the metal lath MR ″ to be manufactured has the first through hole group arranged in the first direction (the right direction in FIG. 13) and the second direction, as in the above embodiment and the modification. And a second through hole group arranged in the left direction in FIG. Therefore, even when the collector 12 ″ molded from the metal lath MR ″ is employed, the same effects as those of the above-described embodiment and modification can be expected.

  Further, the shape of the through holes of the collectors 12, 12 ′, 12 ″ (metal lath MR, MR ′, MR ″) is not limited to the shape of the through holes in the above-described embodiments and modifications. That is, any shape may be used as long as the first through hole group arranged in the first direction and the second through hole group arranged in the second direction different from the first direction can be formed.

  Furthermore, in the said embodiment and modification, the separator main body 11 and the collector 12 were integrally fixed by carrying out metallic joining. However, it goes without saying that the present invention can be implemented without metallicly joining the separator body 11 and the collector 12.

It is the schematic which shows a part of fuel cell stack comprised using the separator for fuel cells using the collector (gas diffusion member) which concerns on embodiment of this invention. It is the schematic perspective view which showed the separator main body which comprises the separator of FIG. (A), (b) is a figure for demonstrating the metal lath which shape | molds a collector (gas diffusion member). (A) is the schematic which showed the metal lath processing apparatus which shape | molds the metal lath of FIG. 3 schematically, (b) is a figure for demonstrating the shape of the blade type | mold of (a). (A)-(c) is the figure shown in order to demonstrate the process cycle in the initial process position of the 1st process of shape | molding the metal lath of FIG. (A)-(c) is the figure shown in order to demonstrate the process cycle in the 3rd process position from the 1st process position of the 1st process of shape | molding the metal lath of FIG. (A)-(c) is the figure shown in order to demonstrate the process cycle in the 1st process position of the 2nd process of shape | molding the metal lath of FIG. (A)-(c) is the figure shown in order to demonstrate the processing cycle in the 2nd processing position of the 2nd process which shape | molds the metal lath of FIG. 3, and a 3rd processing position. It is a schematic exploded perspective view for demonstrating the assembly | attachment state of the flame | frame and MEA shown in FIG. It is a figure for demonstrating meandering of the gas flow by the collector (gas diffusion member) arrange | positioned in gas conduction space. It is a figure for demonstrating the metal lath which forms the collector (gas diffusion member) which concerns on the modification of this invention. It is a figure for demonstrating the blade shape of the upper blade in the metal lath processing apparatus which concerns on the modification of this invention. It is a figure for demonstrating the metal lath which concerns on the modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Separator, 11 ... Separator main body, 12, 12 ', 12 "... Collector (gas diffusion member), 20 ... Frame, 30 ... MEA, MR, MR', MR" ... Metal lath

Claims (10)

A fuel cell separator for supplying a fuel gas and an oxidant gas to an electrode layer constituting an electrode structure of a fuel cell,
A flat separator body that separates the fuel gas and the oxidant gas to prevent mixed flow;
A first through hole group in which a plurality of through holes formed in a mesh shape and a step shape are arranged in a first direction, and a plurality of through holes formed in a mesh shape and a step shape are different from the first direction. A second through hole group arranged in a second direction, and a gas flow path for supplying the fuel gas or the oxidant gas to the electrode layer between the separator body and the electrode layer. A fuel cell separator comprising a gas diffusion member formed by the first through hole group and the second through hole group. The fuel cell separator according to claim 1,
The first through-hole group and the second through-hole group formed in the gas diffusion member are sequentially arranged sequentially with respect to the flow direction of the fuel gas or the oxidant gas. Fuel cell separator. The fuel cell separator according to claim 1,
The gas diffusion member is
A fuel cell separator having a plurality of first through-hole groups arranged in parallel and a plurality of second through-hole groups arranged in parallel. The fuel cell separator according to claim 1,
The gas diffusion member;
From a metal lath in which a first through-hole group forming region in which a plurality of the first through-hole groups are formed in parallel and a second through-hole group forming region in which a plurality of the second through-hole groups are formed in parallel are sequentially formed. A separator for a fuel cell, characterized by being molded. A method for forming a gas diffusion member constituting the fuel cell separator according to claim 1,
A fixed mold for placing a thin plate material, and a moving plate in the sheet thickness direction of the thin plate material that is arranged in the feeding direction of the thin plate material with respect to the fixed mold and moves in the plate width direction of the thin plate material, Using a molding device having a shearing die that forms a through hole by shearing a thin plate material,
The thin plate material is fed by a predetermined processing length, and the shear mold is moved and retracted with respect to the plate thickness direction of the thin plate material to form a through hole, and the shear mold is moved to the thin plate material. A first step of forming the first through hole group by performing each of a plurality of processing positions set in advance in one direction in the plate width direction;
After the first step, a processing cycle in which the thin plate material is fed by a predetermined processing length, the shearing mold is moved in the plate thickness direction of the thin plate material and retracted to form a through hole, And a second step of forming the second through hole group by executing a shearing die for each of a plurality of processing positions set in advance in the other direction in the sheet width direction of the thin plate material. A method for forming a gas diffusion member constituting a fuel cell separator. In the molding method of the gas diffusion member constituting the fuel cell separator according to claim 5,
In the second step, the last machining position among the plurality of preset machining positions in the first step is set as the first of the plurality of preset machining positions in the second step. A method for forming a gas diffusion member constituting a fuel cell separator, wherein the machining cycle is executed as a machining position. In the molding method of the gas diffusion member constituting the fuel cell separator according to claim 5,
A method for forming a gas diffusion member constituting a fuel cell separator, wherein the first step and the second step are sequentially repeated. In the molding method of the gas diffusion member constituting the fuel cell separator according to claim 5,
The shearing die has a plurality of shearing blades formed at predetermined intervals, and is a method for forming a gas diffusion member constituting a fuel cell separator. In the molding method of the gas diffusion member constituting the fuel cell separator according to claim 8,
The shear blade is
A method for forming a gas diffusion member constituting a fuel cell separator, wherein a cross-sectional shape perpendicular to the feeding direction of the thin plate material is a trapezoidal shape or a triangular shape. In the molding method of the gas diffusion member constituting the fuel cell separator according to claim 5,
The machining cycle in the first step is repeatedly executed a plurality of times for each preset machining position,
A method for forming a gas diffusion member constituting a fuel cell separator, wherein the processing cycle in the second step is repeatedly executed a plurality of times for each preset processing position.

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