JP5298758B2 - Gas flow path forming member used for power generation cell of fuel cell and manufacturing method thereof - Google Patents

Description

  The present invention relates to a gas flow path forming member interposed between a gas diffusion layer and a separator in a power generation cell of a fuel cell, and a method for manufacturing the same.

  Conventionally, as a polymer electrolyte fuel cell, what was indicated by patent documents 1 is proposed. This fuel cell is composed of a fuel cell stack in which power generation cells are stacked. The power generation cell includes a membrane-electrode assembly in which an anode electrode layer is formed on one side of an electrolyte membrane and a cathode electrode layer is formed on the other side. Further, the anode electrode layer and the cathode electrode layer are supplied with a fuel gas such as hydrogen gas and an oxidant gas such as air via a gas flow path forming member (collector), thereby forming a membrane-electrode assembly. An electrode reaction occurs to generate electricity. The generated electricity is output to the outside through a collector and a plate-like separator.

Both the gas flow path forming members are required to have an ability to efficiently supply the fuel gas and the oxidant gas to the anode electrode layer and the cathode electrode layer. For this reason, Patent Document 1 discloses an improved gas flow path forming member. This gas flow path forming member is formed of a lath cut metal made of a thin metal plate in which a large number of small through holes having a predetermined shape are formed. In this lath cut metal, for example, a substantially hexagonal through hole is formed in a mesh shape by performing a lath cut process on a stainless steel plate having a thickness of about 0.1 mm. Moreover, the part which forms the mesh-shaped hexagonal through-hole, ie, the ring part (strand), is connected so that it may overlap one another, and the cross-sectional shape is stepped.
JP 2007-87768 A

  In the power generation cell constituting the fuel cell stack, a gas diffusion layer made of carbon paper formed of conductive fibers is interposed between the surfaces of both electrode layers and the gas flow path forming member. The fuel gas and the oxidant gas are efficiently diffused while the fuel gas and the oxidant gas pass through the minute gaps of the gas diffusion layer, and the fuel gas and the oxidant gas are appropriately supplied to each electrode layer. Further, the power generation cell has the following configuration in order to properly make electrical contact between both gas diffusion layers and the gas flow path forming member. A plurality of power generation cells are stacked to form a fuel cell stack. At this time, the upper and lower two separators of the single power generation cell are pressed in a slightly approaching direction, and the gas flow path forming member is pressed against the gas diffusion layer. For this reason, when the conventional gas flow path forming member is used, the following phenomenon occurs. That is. As shown in FIG. 17, for example, in a state where the gas flow path forming member 21 is interposed between the gas diffusion layer 19 bonded to the anode electrode layer 17 and the separator 23, the separator 23 is pressed downward in the drawing. The Then, the contact portion 29 of the gas flow path forming member 21 is strongly pressed against the gas diffusion layer 19. For this reason, since the contact part 29 bites into the gas diffusion layer 19 as shown in FIG. 18, there is the following problem.

  A part of the gas diffusion layer 19 is cut and broken by the contact portion 29, and the function as the gas diffusion layer is lowered. Further, a part of the gas diffusion layer enters the gas flow path of the gas flow path forming member 21, and the effective area is reduced. For this reason, since the pressure loss of the fuel gas increases, there is a problem that the amount of fuel gas supplied decreases and the power generation efficiency decreases. Further, the cut carbon fibers of the gas diffusion layer are caused to flow by the fuel gas and adhere to the capillary narrow gas flow path of the gas flow path forming member, resulting in clogging, which impedes the flow of the fuel gas. This reduces power generation efficiency. Further, there is a problem that the amount of biting of the contact portion 29 of the gas flow path forming member 21 varies for each power generation cell, and the stability of the power generation voltage decreases.

  On the other hand, as shown in FIG. 8, only the shearing blade 33b is formed in the first shearing die 33 located in the lower portion, and the concave portions 34b and the convex portions 34a are alternately formed in the second shearing die 34 located in the upper portion. A method of forming a lath cut metal from a thin metal plate using the lath cut molding apparatus was also employed. In this case, as will be described in detail later, the half ring portion formed on the metal thin plate by the concave portion 34b is moved downward by the half ring portion formed by the convex portion 34a. The bent flat part is formed in the half ring part of the lath cut metal (gas flow path forming member 21) corresponding to the recessed part 34b. As shown in FIG. 19, the bent flat portion 29 a formed in the contact portion 29 of the gas flow path forming member 21 that is in contact with the gas diffusion layer 19 is in surface contact with the gas diffusion layer 19. Therefore, the problem caused by the biting of the contact portion 29 described above can be solved. However, since the bent flat portion 29a is formed widely by one raising / lowering operation of the second shearing die 34, the thickness T dimension of the gas flow path forming member 21 is reduced, and the effective area of the gas flow path is increased. There is a problem that the power generation efficiency is reduced.

  The present invention solves the above-mentioned problems in the prior art, and can suppress the contact portion of the gas flow path forming member from biting into the gas diffusion layer made of the gas diffusion layer, etc. An object of the present invention is to provide a gas flow path forming member used in a power generation cell capable of improving the efficiency and a manufacturing method thereof.

In order to solve the above problems, the invention according to claim 1 is characterized in that a gas flow path forming member is interposed between the gas diffusion layer formed in the electrode layer of the electrode structure and the separator, and the gas flow A gas flow path used in a power generation cell of a fuel cell configured to supply a fuel gas or an oxidant gas to the electrode layer through a gas flow path formed in a path forming member and generate power by an electrode reaction in the electrode layer In the forming member, the gas flow path forming member is formed of a lath cut metal made of a thin metal plate in which a large number of ring portions having through holes of a predetermined shape are connected by a connecting plate portion, and the ring is formed. Forming a bent flat surface portion in surface contact with the gas diffusion layer at a contact portion in contact with the surface of the gas diffusion layer, and connecting the plate portion between the bent flat portion and the connecting plate portion of the ring portion. Same as Forming a non-bent flat portion so as to be positioned on a surface, the bent flat portion and the non-bending plane unit state, and are not molded by plastic deformation by Rasukatto molding device, a plurality of ring portions connecting plate The structure connected by the portion has a first half ring portion composed of a non-bending flat portion and a bending flat portion, and inclined plate portions connected to both sides of the non-bending flat portion and the bending flat portion, and adjacent first A first portion having a plurality of first half-ring portions connected by connecting plate portions, a non-bending flat portion, a bending flat portion, a non-bending flat portion, and A plurality of second half ring portions each having a second half ring portion made of an inclined plate portion connected to both sides of the bent plane portion, wherein the inclined plate portions of the adjacent second half ring portions are connected by a connecting plate portion. A second portion having a half ring portion, wherein the first portion and the second portion are the first portion The second half ring part is arranged with a half pitch deviation with respect to the ring part, and the connecting plate part of the first part and the non-bent flat part of the half ring part of the second part are in the same plane. The gist of the present invention is that the components are connected so as to form .

The gist of a second aspect of the present invention is that, in the first aspect, each of the ring portions is formed in a pentagonal shape or a hexagonal shape as viewed from the gas flow path direction.
According to a third aspect of the present invention, there is provided a method for producing a gas flow path forming member used in the power generation cell of the fuel cell according to the first or second aspect, wherein the first shearing type having a linear shearing blade, the concave portion and the convex shape are provided. Using a second shearing die provided with a shearing blade for forming a plurality of cuts in a thin metal plate in cooperation with the shearing blade at each convex portion at a plurality of locations at a predetermined pitch, A half ring portion including the bent flat portion with respect to an end portion of the metal thin plate in a state in which the metal thin plate is fed at a first feed amount so as to protrude from the first shearing type shearing blade to the second shearing type side. After the first step and the first step, the metal thin plate is fed in a second feed amount so as to protrude from the first shear type shear blade toward the second shear type side. A second step of forming a half ring part including the non-bent flat part with respect to the metal thin plate; After the second step, in fed's state so as to protrude the metal thin plate to said second shearing side of the shear blade of the first shearing at a first feed amount, the metal the second shearing A third step of forming a half ring portion including the bent flat portion with respect to an end portion of the thin metal plate by offsetting in a direction orthogonal to the feeding direction of the thin plate, and after the third step, the thin metal plate is A fourth ring for forming the half ring portion including the non-bent flat portion with respect to the metal thin plate in a state where the feed blade is fed so as to protrude to the second shear die side with respect to the first shear die shear blade at two feed amounts. The process, the first and second steps, and the third and fourth steps are alternately repeated, and a ring portion having a through hole is formed in a mesh shape at a large number of locations on a thin metal plate, thereby forming a lath cut metal. Including the step of performing.

The gist of the invention described in claim 4 is that, in claim 3, the second step is continuously performed a plurality of times, and the fourth step is continuously performed a plurality of times.
(Function)
In this invention, since the bent flat portion is formed in the contact portion that comes into contact with the gas diffusion layer such as carbon paper in the outer peripheral edge of the ring portion that forms the through hole of the gas flow path forming member, the surface of the gas diffusion layer On the other hand, the bent flat portion is brought into surface contact. For this reason, the contact portion does not bite into the gas diffusion layer, the destruction of the gas diffusion layer is prevented, and the destroyed gas diffusion layer enters the gas passage of the gas flow path forming member and the effective area of the gas passage Will not decrease.

  In addition, since the present invention is such that the bent flat portion and the non-bent flat portion are formed by twice the lath cut processing, a wide bent flat portion is formed in the entire width direction of the ring portion by a single lath cut processing. Compared with the above, the formation width of the bent flat portion can be reduced, and the thickness dimension of the gas flow path forming member can be increased correspondingly, the effective area of the gas flow path can be increased, and the power generation efficiency can be improved. Can do.

  According to the present invention, the contact portion of the gas flow path forming member can be prevented from biting into the gas diffusion layer made of carbon paper or the like, and the thickness dimension of the gas flow path forming member can be increased. The effective area of the gas channel can be increased, and the power generation efficiency of the fuel cell can be improved.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
The polymer electrolyte fuel cell stack 11 of this embodiment is formed by stacking a large number of power generation cells 12 as shown in FIG.

  As shown in FIGS. 1 and 2, the power generation cell 12 has a rectangular frame shape, and includes first and first synthetic rubber (or synthetic resin) first and second fuel gas passage spaces S1 and oxidant gas passage spaces S2. Two frames 13 and 14 and MEA 15 (Membrane-Electrode-Assembly) as an electrode structure disposed between the frames 13 and 14 are provided. The power generation cell 12 includes a first gas flow path forming member 21 made of metal housed in the fuel gas passage space S1 and a second gas flow path made of metal housed in the oxidant gas passage space S2. And a forming member 22. Further, the power generation cell 12 includes a first separator 23 made of titanium or a titanium alloy having a flat chamber shape bonded to the upper surface of the frame 13 and the first gas flow path forming member 21, and the frame 14 and the second gas. A second separator 24 made of titanium or a titanium alloy bonded to the lower surface of the flow path forming member 22 is provided. In FIG. 2, the configuration of the gas flow path forming members 21 and 22 is shown in a simplified form as a flat plate.

  On the two opposite parallel sides of the first frame 13, long hole-shaped gas passages 13 a and 13 b are formed, respectively. Gas passages 14a and 14b are formed in two opposite parallel sides of the second frame 14, respectively. The gas passages 13a and 13b and the gas passages 14a and 14b are formed on sides that do not correspond to each other.

  The MEA 15 includes an electrolyte membrane 16 as shown in FIGS. 1 and 2, an anode electrode layer 17 and a cathode electrode layer 18 formed by laminating a predetermined catalyst on the upper and lower surfaces of the electrolyte membrane 16 shown in the drawing, The electrode layers 17 and 18 are composed of gas diffusion layers 19 and 20 made of, for example, carbon paper having electrical conductivity bonded to the surfaces of the electrode layers 17 and 18, respectively.

Gas inlets 23a and 24a are formed on two orthogonal sides of the first and second separators 23 and 24, and gas outlets 23b and 24b are formed on the other two orthogonal sides.
As shown in FIG. 3, the first and second gas flow path forming members 21 and 22 are formed of a metal lath cut metal 25 (hereinafter simply referred to as a lath metal) having a plate thickness of about 0.1 mm. As shown in FIG. 4, the lath metal 25 has substantially hexagonal through holes 26 formed in a staggered manner at a large number of locations. A portion where the through hole 26 is formed is called a ring portion 27, and these ring portions 27 are connected so as to sequentially overlap each other by a connecting plate portion 28 (portions given with dots in FIG. 3).

  As shown in FIGS. 3 and 4, the upper half ring portion R1 of the ring portion 27 is integrally connected to the pair of left and right first inclined plate portions 27a and the upper end portions of both inclined plate portions 27a. It is comprised by the 1st flat plate part 27b. The lower half ring portion R2 in the figure of the ring portion 27 is composed of a pair of left and right second inclined plate portions 27c and a second flat plate portion 27d integrally connected to the lower ends of both the second inclined plate portions 27c. It is configured.

  As shown in FIG. 3, the connecting plate portion 28 is the same plate portion as the second flat plate portion 27 d of the ring portion 27. A first contact portion 29 that is in contact with the surface of the gas diffusion layer 19 is formed at an end portion of the first flat plate portion 27b of the ring portion 27 opposite to the connection plate portion 28 (flat plate portion 27d). . The bent flat portion 29a is formed in the first contact portion 29, and the bent flat portion 29a is in surface contact with the gas diffusion layer 19 (20) as shown in FIGS. An end portion of the second flat plate portion 27d connected to the first flat plate portion 27b of the ring portion 27 serves as a second contact portion 30 that is in line contact with the inner surface of the first or second separator 23, 24.

  A first flat plate portion 27b between the bent flat portion 29a and the connecting plate portion 28 (lower flat plate portion 27d) is a non-bending flat portion 27f located on the same plane as the connecting plate portion 28. . As shown in FIG. 5, the bending angle α of the bending plane portion 29a with respect to the connecting plate portion 28 (non-bending plane portion 27f) is set in a range of 60 to 70 °, and in this embodiment is set to 65 °. Yes. A first flat plate portion 27b is formed by the non-bending flat portion 27f and the bending flat portion 29a.

  As shown in FIG. 1, the first and second gas flow path forming members 21 and 22 are disposed in the fuel gas passage space S1 and the oxidant gas passage space S2 of the first and second frames 13 and 14, respectively. The surfaces of the gas diffusion layers 19 and 20 and the inner surfaces of the first and second separators 23 and 24 are in contact with each other.

  As indicated by an arrow G1 in FIG. 2, the fuel gas introduced into the fuel gas passage space S1 from one gas inlet 23a of the first separator 23 is one gas outlet 23b and the gas passage 14b of the second frame 14. The first gas flow path forming member 21 is accommodated so as to flow to one gas outlet port 24 b of the second separator 24. As indicated by an arrow G2 in FIG. 2, the oxidant introduced into the oxidant gas passage space S2 of the second frame 14 from the other gas introduction port 23a of the first separator 23 through the gas passage 13a of the first frame 13. The second gas flow path forming member 22 is accommodated so that the gas flows through the gas passage 13b of the first frame 13 to the other gas outlet 23b and the other gas outlet 24b of the second separator 24.

  In this embodiment, the first and second frames 13 are designed from the viewpoint of sealing the gas on the contact surface between the first frame 13 and the electrolyte membrane 16 and the contact surface between the first frame 13 and the second frame 14 shown in FIG. , 14 are formed of synthetic rubber. For this reason, when the fuel cell stack 11 is configured by stacking the power generation cells 12, the first and second gas flow path forming members 21 and 22 are connected to the first and second separators 23, 22 by the fastening load of the stack 11. 24 is assembled in a state of being slightly pressed to the MEA 15 side. Accordingly, the surface contact state between the bent flat surface portion 29 a of the first contact portion 29 of the first gas flow path forming member 21 and the gas diffusion layer 19 is appropriately maintained. The second gas flow path forming member 22 side is configured in the same manner as the above-described structure on the gas flow path forming member 21 side.

  In the fuel cell stack 11, between the stacked power generation cells 12, one gas introduction port 23 a of the first separator 23 and one gas introduction port 24 a of the second separator 24 are fuel gas passages of the first frame 13. Through the space S1 and the gas passage 14a of the second frame 14, all are in communication with each other, and a fuel gas (hydrogen gas) flow passage is formed. On the other hand, the other gas introduction port 23a of the first separator 23 and the other gas introduction port 24a of the second separator 24 pass through the gas passage 13b of the first frame 13 and the oxidant gas passage space S2 of the second frame 14, respectively. All are in communication with each other, and an oxidant gas (air) flow passage is formed. The fuel gas and the oxidant gas supplied to the fuel gas flow passage and the oxidant gas flow passage are supplied to the fuel gas passage space S1 and the oxidant gas passage space by the first and second gas flow passage forming members 21 and 22, respectively. It will flow uniformly in S2. That is, the fuel gas in the fuel gas passage space S1 becomes turbulent by passing through a large number of zigzag through holes 26 formed in the first gas flow path forming member 21, and the fuel gas is in the gas passage space S1. It is in a state of being uniformly diffused inside. The fuel gas is appropriately diffused by passing through the gas diffusion layer 19, and the fuel gas is uniformly supplied to the anode electrode layer 17. Electric power is generated by the electrode reaction occurring in the MEA 15 by supplying the fuel gas and the oxidant gas. Since a plurality of power generation cells 12 are stacked, a desired output can be obtained.

Next, a lath cut molding apparatus used in the method for manufacturing the first and second gas flow path forming members 21 and 22 will be described.
The first gas flow path forming member 21 is molded using a lath cut molding apparatus shown in FIG. This lath cut forming apparatus includes a pair of upper and lower feed rollers 31 for sequentially supplying the metal thin plates 25A. In addition, the forming apparatus includes a forming mechanism 32 that cuts the thin plate 25A at a large number of locations and bends and stretches the metal thin plate 25A corresponding to the cut so as to be plastically deformed. By this forming mechanism 32, a large number of hexagonal through holes 26 (ring portions 27) having a mesh shape are formed in the metal thin plate 25 </ b> A in a step shape, and the lath metal 25 is formed.

  As shown in FIG. 8, the forming mechanism 32 includes, in a predetermined position, a first shear die 33 fixed to a support base (not shown), a vertical direction and a feeding direction of the metal thin plate 25A by an elevator mechanism and an offset mechanism (not shown). The second shearing die 34 is capable of reciprocating in the orthogonal width direction (direction orthogonal to the paper surface of FIG. 7). A straight shearing blade 33b is formed on an edge of the upper surface 33a that supports the thin metal plate 25A of the first shearing die 33 on the downstream side in the feed direction of the thin metal plate 25A, and the lower side of the shearing blade 33b is a planar position. It is a regulation surface 33c.

  On the lower portion of the second shearing die 34, convex portions 34a and concave portions 34b are alternately formed at a plurality of locations at a predetermined pitch in the horizontal direction. A horizontal molding surface 34c is formed at the lower end of the convex portion 34a of the second shear mold 34, and inclined molding surfaces 34d are formed on both the left and right sides of the convex portion 34a. The left and right side surfaces of the concave portion 34b are the same molding surfaces as the inclined molding surface 34d of the convex portion 34a. A horizontal molding surface 34e is formed on the inner top surface of the recess 34b. An inverted trapezoidal shape that cuts the thin metal plate 25A in cooperation with the shearing blade 33b of the first shearing die 33 at the upstream edge of the metal thin plate 25A in the feeding direction of the forming surface 34c and the inclined forming surface 34d. A shearing blade 34f is formed.

Next, a method of forming the gas flow path forming member 21 using the forming apparatus configured as described above will be described with reference to FIGS.
By the feed roller 31 shown in FIG. 7, as shown in FIG. 9A, the thin metal plate 25A is fed at a predetermined first feed amount L1 (for example, 0.2 mm) more than the shear blade 33b of the first shear die 33. It is sent so as to protrude partway in the molding region on the downstream side in the direction. In this state, the second shear mold 34 is lowered toward the first shear mold 33, and a part of the thin metal plate 25A is sheared by the shear blade 33b of the first shear mold 33 and the shear blade 34f of the second shear mold 34. Thus, a large number of cuts are formed. Next, as shown in FIGS. 10A and 10B, the second shear die 34 is lowered to the lowest point position, and the metal thin plate 25A in contact with the convex portion 34a of the second shear die 34. Bend down and extend. A portion bent and stretched by the convex portion 34a has a substantially inverted trapezoidal shape as shown in FIG. On the contrary, the metal thin plate 25A that has entered the recess 34b has a substantially trapezoidal shape.

  In the first step, the second flat plate portion 27d (the connecting plate portion 28) that forms the lower half ring portion R2 of the ring portion 27 has the convex portion 34a as shown in FIG. Since it is forced down by the horizontal molding surface 34c, it is molded in a horizontal state. However, since the metal thin plate 25A corresponding to the concave portion 34b is not provided with a convex portion that enters the concave portion 34b in the first shearing die 33, it is not forcedly pushed from below. For this reason, the first flat plate portion 27b of the upper half ring portion R1 of the ring portion 27 formed by the recess 34b is downward with respect to the shearing blade 33b of the first shearing die 33 as shown in FIG. The bent flat portion 29 a having a bending angle α is formed with respect to the horizontal metal thin plate 25 </ b> A, and this becomes the first contact portion 29. Thereafter, as shown in FIGS. 11A and 11B, the second shearing die 34 returns from the lowest point position to the upper original position.

  Subsequently, as shown in FIG. 11A, the metal thin plate 25A is moved by the feed roller 31 shown in FIG. 7 at a predetermined second feed amount L2 (for example, 0.1 mm) from the shearing blade 33b of the first shearing die 33. Is also fed so as to protrude to the second shearing die 34 side. In this state, as shown in FIGS. 12 (a) and 12 (b), the second shearing die 34 is lowered again at the same position where it is not offset in the left-right direction, and the upper edge of the ring portion 27 is placed on the edge of the metal thin plate 25A. Half ring part R1 and lower half ring part R2 are formed. At this time, the first flat plate portion 27b of the upper half ring portion R1 is in a free state like the first contact portion 29. However, the second feed amount L2 of the first flat plate portion 27b is equal to that of the contact portion 29. It is smaller than the first feed amount L1. For this reason, the first flat plate portion 27b is positioned in the vicinity of the shearing blade 33b of the first shearing die 33, and can easily follow the horizontal forming surface 34e of the recess 34b of the second shearing die 34, and the sagging downward is almost eliminated. Disappear. For this reason, the first flat plate portion 27b on the rear side of the bent flat portion 29a does not hang downward as shown in FIG. 12B, and is held in a substantially horizontal state, and the first flat plate portion 27b is not bent flat. Part 27f. By this second step, the half ring portions R1 and R2 including the non-bending flat portion 27f are formed.

  As described above, the half ring portions R1 and R2 that are originally formed by one molding operation are molded in two steps, and the bent plane portion 29f that is molded the first time is followed by the non-bent plane portion 27f. Therefore, the formation width of the bent flat portion 29a is suppressed to an appropriate width as compared with the case where the formation is performed only once.

  Next, as shown in FIG. 13A, after the second shearing die 34 is raised and moved to the original position, the thin metal plate 25A is again fed by the first feed amount L1. Further, as shown in FIG. 13B, after moving the second shearing die 34 to the right or left by, for example, a half pitch of the arrangement pitch of the ring portions 27, the second shearing die 34 is moved as described above. The metal sheet 25A is lowered and formed as shown in FIGS. 14 (a) and 14 (b). A plurality of ring portions 27 are formed by forming a half ring portion R1 above the half ring portion R2 and forming a half ring portion R2 above the half ring portion R1. After this third step, as shown in FIGS. 15 (a) and 15 (b), the second thin plate 34 remains in the offset state as described above, and the thin metal plate 25A is fed by the second feed amount L2, and the second The shearing die 34 is lowered to mold the half ring portions R1 and R2 as shown in FIGS. By this fourth step, the half ring portions R1 and R2 including the non-bending flat portion 27f are formed.

  Thereafter, the lath metal 25 is formed as shown in FIGS. 3 to 5 by alternately repeating the first and second steps and the third and fourth steps described above. As shown in FIG. 3, the lath metal 25 is formed with a ring portion 27 having a large number of mesh-like through holes 26 in a staggered manner.

  The thin metal plate 25A that is not sheared by the shearing blade 34f provided on the convex portion 34a of the second shearing die 34 remains as a portion where the cut is not processed in the lath metal 25. The ring part 27 is connected so that it may overlap one another by the connection plate part 28 (second flat plate part 27d) being the unbroken part, and the cross-sectional shape of the lath metal 25 is as shown in FIG. 3 and FIG. It is formed in steps.

  When the manufacture of the lath metal 25 is completed in this way, the first and second gas flow path forming members 21 and 22 shown in FIGS. 1 and 2 are formed by cutting the lath metal 25 into a predetermined dimension.

  The first gas flow path forming member 21 manufactured as described above is incorporated in the power generation cell 12 as shown in FIG. 1, and the first gas flow path forming member 21 is formed on the upper surface of the gas diffusion layer 19 as shown in FIG. The bent flat surface portion 29 a of the first contact portion 29 of the path forming member 21 is in surface contact, and the second contact portion 30 is in line contact with the back surface of the first separator 23.

According to the first and second gas flow path forming members 21 and 22 of the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the first and second gas flow path forming members 21 and 22 housed in the fuel gas passage space S1 and the oxidant gas passage space S2 of the first and second frames 13 and 14 are replaced with the lath metal 25. Was molded by. Then, a bent flat portion 29 a was formed with respect to the first contact portion 29 that is in contact with the surface of the gas diffusion layer 19 of the ring portion 27 of the lath metal 25. For this reason, the contact state between the gas diffusion layer 19 formed from the fiber and the first contact portion 29 can be in surface contact, and the first contact portion 29 is prevented from biting into the surface of the gas diffusion layer 19. Can do. Accordingly, the gas diffusion layers 19 and 20 enter the fuel gas flow path and the oxidant gas flow path of the first and second gas flow path forming members 21 and 22, and the fuel gas passage space S1 and the oxidant gas passage space S2 It is possible to prevent the effective cross-sectional area from being reduced, and it is possible to avoid a reduction in power generation efficiency due to a decrease in the supply amount of fuel gas and oxidant gas.

  Further, as compared with the case where the first contact portion 29 is in line contact with the gas diffusion layers 19, 20, the electrical connection between the gas diffusion layers 19, 20 and the first and second gas flow path forming members 21, 22 is achieved. By appropriately connecting, the flow of electricity from the gas diffusion layers 19 and 20 to the first and second gas flow path forming members 21 and 22 becomes smooth, and the current collection efficiency can be improved. Furthermore, damage to the contact portions of the gas diffusion layers 19 and 20 with which the first contact portion 29 is contacted can be prevented. For this reason, it is possible to prevent, for example, carbon fibers cut from the carbon paper forming the gas diffusion layers 19 and 20 from being clogged in the gas passages of the gas flow path forming members 21 and 22, and to ensure power generation performance. .

  (2) In the above embodiment, the ring portion 27 is formed in one step by the first shearing die 33 which is not originally provided except the shearing blade 33b and the second shearing die 34 having the convex portion 34a and the concave portion 34b. The half ring portions R1 and R2 were each formed in two steps. For this reason, as shown in FIG. 5, the formation width W1 of the bent flat portion 29a is narrowed, and the dimension of the thickness T1 of the gas flow path forming member 21 is set to be larger than that in a single step. Therefore, the effective area of the gas flow path in the gas flow path forming member 21 can be secured, the gas can be properly supplied, and the power generation efficiency can be improved. If the half ring portions R1 and R2 are molded in a single process, the bent flat portion 29a of the contact portion 29 has a larger formation width W2 as shown by the two-dot chain line in FIG. The contact portion 29 is displaced downward, and the thickness T2 decreases. For this reason, the effective area of the gas flow path of the gas flow path forming member 21 is reduced, and the power generation efficiency is reduced.

  (3) In the above-described embodiment, since it is only necessary to use the first shear mold 33 and the second shear mold 34 having a simple structure shown in FIGS. Can be simplified, and the bent flat portion 29 a can be easily formed with respect to the first contact portion 29 of the ring portion 27.

In addition, you may change the said embodiment as follows.
Although not shown, a molding surface for sandwiching the metal thin plate 25A may be provided between the front side surface of the first shearing die 33 and the horizontal molding surface 34c of the convex portion 34a of the second shearing die 34. . In this case, the second flat plate portion 27d of the ring portion 27 can be prevented from being bent.

The second step shown in FIGS. 11 and 12 and the fourth step shown in FIGS. 15 and 16 may be performed in a plurality of times.
In the embodiment, the second shear mold 34 is offset in the left-right direction by a half pitch of the formation pitch of the convex portions and the concave portions 34a and 34b of the second shear mold 34, and the half ring portions R1 and R2 are formed. However, the offset amount may be changed as appropriate. Further, the ring portions 27 need not be arranged in a staggered manner.

-You may shape the shape of the said ring part 27 to pentagonal shape other than hexagonal shape, for example.
-As a material of the 1st, 2nd gas flow path formation members 21 and 22, you may use metal plates, such as a stainless plate, aluminum, copper, etc. which have electroconductivity.

FIG. 3 is a partially omitted vertical cross-sectional view of a fuel cell stack in which power generation cells including first and second gas flow path forming members of the present invention are stacked. The perspective view of the state which isolate | separated the component of the power generation cell. The partial expansion perspective view of the 1st gas flow path formation member used for a power generation cell. The partial front view of the 1st gas flow path formation member. The fragmentary sectional view of the 1st gas channel formation member. The expanded fragmentary sectional view of the lamination | stacking state of a gas diffusion layer, the 1st gas flow path formation member, and a 1st separator. Sectional drawing which shows the lath metal lath cut molding apparatus. The partial perspective view of a 1st shear type and a 2nd shear type. (A) is a sectional side view which shows the manufacturing process of a gas flow path formation member, (b) is a partial front view similarly. (A) is a sectional side view which shows the manufacturing process of a gas flow path formation member, (b) is a partial front view similarly. (A) is a sectional side view which shows the manufacturing process of a gas flow path formation member, (b) is a partial front view similarly. (A) is a sectional side view which shows the manufacturing process of a gas flow path formation member, (b) is a partial front view similarly. (A) is a sectional side view which shows the manufacturing process of a gas flow path formation member, (b) is a partial front view similarly. (A) is a sectional side view which shows the manufacturing process of a gas flow path formation member, (b) is a partial front view similarly. (A) is a sectional side view which shows the manufacturing process of a gas flow path formation member, (b) is a partial front view similarly. (A) is a sectional side view which shows the manufacturing process of a gas flow path formation member, (b) is a partial front view similarly. Sectional drawing which shows the laminated structure of the gas diffusion layer of a conventional power generation cell, a gas flow path formation member, and a separator. Sectional drawing which shows the state by which the separator was pressed with respect to the gas diffusion layer. Sectional drawing which shows the laminated structure of the gas diffusion layer of a conventional power generation cell, a gas flow path formation member, and a separator.

Explanation of symbols

  R1, R2 ... half ring part, 27 ... ring part, 12 ... power generation cell, 17 ... electrode layer, 19, 20 ... gas diffusion layer, 21, 22 ... gas flow path forming member, 25 ... lath cut metal, 25A ... metal thin plate , 26 ... through-hole, 27 f ... non-bending flat part, 28 ... connecting plate part, 29 ... contact part, 29 a ... bending flat part, 33 ... first shearing type, 33b, 34f ... shearing blade, 34 ... second shearing type , 34a ... convex portion, 34b ... concave portion.

Claims (4)

A gas flow path forming member is interposed between the gas diffusion layer formed in the electrode layer of the electrode structure and the separator, and the fuel gas or the gas layer is formed in the electrode layer by the gas flow path formed in the gas flow path forming member. In the gas flow path forming member used for the power generation cell of the fuel cell configured to supply the oxidant gas and generate power by the electrode reaction in the electrode layer,
The gas flow path forming member is formed of a lath cut metal made of a thin metal plate formed by connecting a plurality of ring portions having through holes of a predetermined shape by a connecting plate portion, and the ring portion of the ring portion A bent flat portion that is in surface contact with the gas diffusion layer is formed at a contact portion that contacts the surface of the gas diffusion layer, and is flush with the connecting plate portion between the bent flat portion and the connecting plate portion of the ring portion. the non-bending flat portion formed so as to be located, the bent flat portion and the non-bending plane unit state, and are not molded by plastic deformation by Rasukatto molding device,
A structure in which a plurality of ring parts are connected by a connecting plate part includes a non-bending flat part and a bending flat part, and a first half ring part comprising inclined plate parts connected to both sides of the non-bending flat part and the bending flat part. A first portion having a plurality of first half-ring portions connected by connecting plate portions, and a non-bending plane portion and a bending plane portion. And a second half ring part composed of an inclined plate part connected to both sides of the non-bending flat part and the bent flat part, and the inclined plate parts of the adjacent second half ring parts are connected plate parts. A second portion having a plurality of second half-ring portions connected, the first portion and the second portion being a second half-ring portion relative to the first half-ring portion Are arranged in a state shifted by a half pitch, and the connecting plate portion of the first portion and the non-bending flat portion of the half ring portion of the second portion are the same plane. Gas flow path forming member used in the power generation cell of a fuel cell characterized by so as to form a connected structure. 2. The gas flow path forming member used in a power generation cell of a fuel cell according to claim 1, wherein each of the ring portions is formed in a pentagonal shape or a hexagonal shape as viewed from a gas flow path direction. In the manufacturing method of the gas flow path formation member used for the power generation cell of the fuel cell according to claim 1 or 2,
A first shear type having a linear shear blade;
A second shearing die having a plurality of recesses and projections at a predetermined pitch and provided with a shearing blade for forming a plurality of cuts in the metal thin plate in cooperation with the shearing blade at each projection. make use of,
A half ring portion including the bent flat portion with respect to an end portion of the metal thin plate in a state in which the metal thin plate is fed at a first feed amount so as to protrude from the first shearing type shearing blade to the second shearing type side. A first step of molding
After the first step, the thin metal plate is fed to the metal thin plate with a second feed amount so as to protrude from the first shearing type shearing blade to the second shearing type side. A second step of forming a half ring part including the part;
After the second step, the metal plate is fed at a first feed amount so as to protrude from the first shearing type shearing blade toward the second shearing type, and the second shearing type is moved to the metal. A third step of forming a half ring part including the bent plane part with respect to an end part of the metal thin plate by offsetting in a direction perpendicular to the feeding direction of the thin plate;
After the third step, the non-bent flat surface of the metal thin plate is fed to the metal thin plate in a state where the metal thin plate is fed at a second feed amount so as to protrude from the first shearing type shearing blade to the second shearing type side. A fourth step of forming the half ring part including the part;
The above first and second steps and the third and fourth steps are alternately repeated, and a ring portion having through holes is formed in a mesh shape at a large number of locations on the metal thin plate, and a lath cut metal is formed; ,
The manufacturing method of the gas flow path formation member used for the power generation cell of a fuel cell characterized by including these. 4. A gas flow path forming member for use in a power generation cell of a fuel cell according to claim 3, wherein the second step is continuously performed a plurality of times, and the fourth step is continuously performed a plurality of times. Method.

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