JP6927025B2 - Fuel cell separator manufacturing equipment and fuel cell separator manufacturing method - Google Patents

Description

The present invention relates to a fuel cell separator manufacturing apparatus and a fuel cell separator manufacturing method.

The polymer electrolyte fuel cell includes a fuel cell stack formed by stacking a plurality of single cells. The single cell has a membrane electrode assembly and a pair of separators that sandwich the membrane electrode assembly.

The membrane electrode assembly includes an electrolyte membrane made of an ion exchange membrane made of a solid polymer material, a fuel electrode (anode) provided on one surface of the electrolyte membrane, and air provided on the other surface of the electrolyte membrane. It has a pole (cathode).

The pair of separators are each made of a conductive material such as metal. A gas passage for supplying a fuel gas such as hydrogen to the fuel electrode is formed on the surface of the separator provided on the fuel electrode side of the membrane electrode assembly on the fuel electrode side. A gas passage for supplying an oxidizing gas such as air is formed on the air electrode side surface of the separator provided on the air electrode side of the membrane electrode assembly. Further, the separators of the single cells adjacent to each other in the stacking direction are in contact with each other, and a cooling passage through which the cooling medium flows is formed on the facing surface of these separators.

By supplying the fuel gas and the oxidizing gas through each gas passage, an electrochemical reaction between the fuel gas and the oxidizing gas occurs in the membrane electrode junction, and an electromotive force is obtained accordingly.
Such a gas passage and a cooling passage are composed of a large number of grooves provided on both sides of the separator (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2007-48616

By the way, in order to ensure the sealing property, conductivity, and heat transferability between the separator and the membrane electrode assembly or between the separators, the back surface of the bottom surface of each groove of the separator is formed to join the separator and the membrane electrode. It is necessary to secure the contact area with the body and the contact area between the separators.

However, when trying to mold a separator material made of a metal plate material at once using a press die, there is a problem that the processing cost increases due to the high precision required for the die, and a large molding load is required. There is a problem that the device becomes large.

On the other hand, in the separator manufacturing apparatus and manufacturing method described in Patent Document 1, the separator material is first bent using a pair of first molding dies to temporarily mold the portion to be the groove portion. Next, using a pair of second molding dies, the groove portion is main-molded by compressing the separator material on which the portion is molded.

However, in this case, there is a trade-off that two types of molding dies are required and two molding steps are required.
An object of the present invention is to provide a fuel cell separator manufacturing apparatus and a fuel cell separator manufacturing method capable of molding a separator by a single pressing step while suppressing a molding load.

The apparatus for manufacturing a fuel cell separator for achieving the above object has a first having a molded surface in which a first convex portion and a pair of first concave portions provided so as to sandwich the first convex portion are extended. A second concave portion that is provided between the molding die and each of the pair of second convex portions facing each of the first concave portions and the second convex portion and facing the first convex portion is extended. A second molding die having a molding surface is provided, and a large number of grooves are formed on both sides of the metal plate material by pressing the metal plate material with the first molding die and the second molding die. The bottom surface of the second recess is provided with a ridge extending along the extending direction of the second recess, and the top surface of the first convex portion faces the ridge and is said to be the same. A concave groove extending along the extending direction of the first convex portion and having a depth larger than the protruding height of the ridge is provided.

According to the same configuration, when the metal plate material is pressed by the first molding die and the second molding die, the metal plate material is first formed into a corrugated shape so as to follow the uneven shape of each molding surface. When the first molding die and the second molding die are further brought close to each other from this state, the portion of the metal plate material that is pressed by the first convex portion and protrudes into the second concave portion (hereinafter, the first protruding portion) becomes the first. 2 Pressed against the ridge of the recess. Then, when the first molding die and the second molding die are further brought close to each other from this state, the first protruding portion is bent and deformed with the ridge as a fulcrum, and is deformed along the bottom surface of the second concave portion. After that, a compression load is applied to the portion of the metal plate material between the first convex portion and the second concave portion by the top surface of the first convex portion and the bottom surface of the second concave portion, so that the first protruding portion is formed. The tip of the separator is formed into the bottom of the groove on one side of the separator. A part of the first protruding portion facing the top surface of the first convex portion is escaped into the concave groove, but the depth of the concave groove is larger than the protruding height of the ridge. Therefore, a gap is generated between the groove and the groove.

On the other hand, the portion of the metal plate material that is pressed by the second convex portion and protrudes into the first concave portion (hereinafter referred to as the second protruding portion) is compressed by the top surface of the second convex portion and the bottom surface of the first concave portion. Weight works. As a result, the tip portion of the second protruding portion is formed on the bottom portion of the groove portion on the other surface of the separator.

As described above, according to the above configuration, the bottom portion of the groove portion on one surface of the separator is formed by compression loading, and the groove portion on the other surface is formed by compression loading while using the bending stress associated with the bending deformation. Therefore, the load required for pressing can be reduced as compared with the case where the bottoms of the grooves on both sides are formed only by compression loading. Therefore, the separator can be formed by one pressing process while suppressing the forming load.

Further, a method for manufacturing a fuel cell separator for achieving the above object is a first molding mold in which a first convex portion and a pair of first concave portions provided so as to sandwich the first convex portion are extended. , A second molding provided between each of the pair of second convex portions facing each of the first concave portions and the second convex portions, and the second concave portions facing the first convex portions are extended respectively. By pressing a metal plate material with a mold, a large number of grooves are formed on both sides thereof. The bottom surface of the second concave portion is provided with a ridge extending along the extending direction of the second concave portion, and the top surface of the first convex portion faces the ridge and is said to be the same. A concave groove extending along the extending direction of the first convex portion and having a depth larger than the protruding height of the ridge is provided, and the top surface of the second convex portion and the first concave portion are provided. While the metal plate material is formed by the compression load by the bottom surface, the bending stress is formed by using the ridge as a fulcrum prior to forming the metal plate material by the compression load by the top surface of the first convex portion and the bottom surface of the second concave portion. To act.

According to this method, it is possible to obtain an action and effect similar to the action and effect of the above-mentioned fuel cell separator manufacturing apparatus.

According to the present invention, the separator can be molded by a single pressing step while suppressing the molding load.

An enlarged cross-sectional view of a fuel cell stack centered on a single cell having the separator for one embodiment of a fuel cell separator manufacturing apparatus. The cross-sectional view of the manufacturing apparatus of the separator for a fuel cell of the same embodiment. FIG. 5 is a cross-sectional view showing a state immediately before the base material is pressed in the manufacturing process of the fuel cell separator of the same embodiment. FIG. 5 is a cross-sectional view showing a state in which the base material is being pressed in the process of manufacturing the fuel cell separator of the same embodiment. FIG. 5 is a cross-sectional view showing a state immediately after the pressing of the base material is completed in the manufacturing process of the fuel cell separator of the same embodiment.

Hereinafter, an embodiment of a fuel cell separator manufacturing apparatus will be described with reference to FIGS. 1 to 5.
The fuel cell separator manufacturing apparatus (hereinafter, manufacturing apparatus) of the present embodiment is an apparatus for manufacturing the separator 20 used in the stack 100 of the polymer electrolyte fuel cell shown in FIG. The separator 20 is a general term for a pair of separators 21 and 22 described later.

As shown in FIG. 1, the stack 100 has a structure in which a plurality of single cells 10 are stacked. The single cell 10 is a gas composed of a membrane electrode assembly 11 sandwiched between a pair of separators 21 and 22 having an uneven shape, and carbon fibers interposed between the membrane electrode assembly 11 and the separators 21 and 22. It includes a diffusion layer 14. The membrane electrode assembly 11 includes an electrolyte membrane 12 which is an ion exchange membrane, and a pair of catalyst electrode layers 13 that sandwich the electrolyte membrane 12.

On both sides of one separator 21, extending first groove portions 21a and second groove portions 21b are alternately arranged side by side. Further, on both surfaces of the other separator 22, extending first groove portions 22a and second groove portions 22b are alternately arranged side by side. The back surfaces (bottom surface and upper surface of FIG. 1) of the bottom surfaces of the first groove portions 21a and 22a of the separators 21 and 22 are in contact with each gas diffusion layer 14. The portion partitioned by the second groove portion 21b of one separator 21 and the gas diffusion layer 14 of one side is a gas flow path through which a fuel gas such as hydrogen flows. The portion partitioned by the second groove portion 22b of the other separator 22 and the other gas diffusion layer 14 is a gas flow path through which an oxidizing gas such as air flows.

Further, the back surface of the bottom surface of the second groove portion 21b of one separator 21 (upper surface of FIG. 1) and the back surface of the second groove portion 22b of the other separator 22 adjacent to the separator 21 are in contact with each other (lower surface of FIG. 1). Has been done. The portion partitioned by the first groove portion 21a of one separator 21 and the first groove portion 22a of the other separator 22 facing the first groove portion 21a is a cooling flow path through which cooling water flows.

The separators 21 and 22 are formed of, for example, a metal material such as stainless steel or titanium.
Next, the manufacturing apparatus will be described.

As shown in FIG. 2, the manufacturing apparatus includes a movable first molding die 30 and a fixed second molding die 60. The first molding die 30 is provided so as to be able to advance and retreat with respect to the second molding die 60.

The first molding die 30 has a molding surface 31 in which the extending first convex portion 40 and the first concave portion 50 are alternately provided. The first convex portion 40 has a top surface 41 and a pair of side surfaces 42. The distance between the pair of side surfaces 42 is reduced so as to be closer to the top surface 41 in the projecting direction (vertical direction in the figure) of the first convex portion 40. The corner 43 between the top surface 41 and each side surface 42 is curved. The corner between the bottom surface 51 of the first recess 50 and each side surface 42 is curved. The top surface 41 of the first convex portion 40 is provided with a concave groove 40a having an arcuate cross section extending along the extending direction of the first convex portion 40 (the direction perpendicular to the paper surface in the figure).

The second molding die 60 has a molding surface 32 in which the extending second convex portion 70 and the second concave portion 80 are alternately provided. The second convex portion 70 has a top surface 71 and a pair of side surfaces 72. The distance between the pair of side surfaces 72 is reduced so as to be closer to the top surface 71 in the projecting direction (vertical direction in the figure) of the second convex portion 70. The corners of the top surface 71 and each side surface 72 are curved. The corner between the bottom surface 81 of the second recess 80 and each side surface 72 is curved. The bottom surface 81 of the second recess 80 is provided with a ridge 80a having an arcuate cross section that faces the recess 40a and extends along the extending direction of the second recess 80 (the direction perpendicular to the paper surface in the figure). ing. The depth of the concave groove 40a is made larger than the protruding height of the ridge 80a.

Here, the inclination angle of each side surface 72 of the second convex portion 70 with respect to the bottom surface 81 of the second concave portion 80 is made larger than the inclination angle of each side surface 42 of the first convex portion 40 with respect to the bottom surface 51 of the first concave portion 50. There is.

The operation of this embodiment will be described.
In the manufacturing apparatus of this embodiment, the separator 20 is manufactured as follows.
As shown in FIG. 3, first, the base material 120, which is the material of the separator 20, is placed on the second convex portion 70 of the second molding die 60.

Next, the first molding die 30 is displaced toward the second molding die 60. As a result, as shown in FIG. 4, the base material 120 is formed into a corrugated shape so as to follow the uneven shape of the molding surfaces 31 and 32.

After that, when the first molding die 30 is further brought closer to the second molding die 60, a portion of the base material 120 that is pressed by the first convex portion 40 and protrudes into the second concave portion 80 (hereinafter, the first protruding portion). 130) is pressed against the ridge 80a of the second recess 80.

Then, when the first molding die 30 is further brought closer to the second molding die 60, the first protruding portion 130 is bent and deformed with each corner portion 43 of the first convex portion 40 and the ridge 80a as fulcrums, and the first protruding portion 130 is bent and deformed. 2 Deforms along the bottom surface 81 of the recess 80.

After that, as shown in FIG. 5, a compressive load is applied to the first protruding portion 130 of the base material 120 by the top surface 41 of the first convex portion 40 and the bottom surface 81 of the second concave portion 80. Here, a relief portion 90 is formed between the first protruding portion 130 of the base material 120 and each side surface 72 of the second convex portion 70. The length of the relief portion 90 in the width direction of the first convex portion 40 (the left-right direction of FIGS. 4 and 5) is reduced toward the top surface 71 of the second convex portion 70. As described above, since the bending stress and the compressive load (compressive stress) associated with the bending deformation are applied to the first protruding portion 130, the first protruding portion 130 is deformed so as to escape to the relief portion 90. Therefore, the tip surface of the first protruding portion 130 is a flat surface. As a result, the tip portion of the first protruding portion 130 is formed on the bottom portion of the groove portion on one surface of the separator 20. As shown in FIG. 5, a part of the first protruding portion 130 facing the top surface 41 of the first convex portion 40 is released into the concave groove 40a. As described above, since the depth of the recessed groove 40a is made larger than the protruding height of the ridge 80a, a gap 91 is formed between the recessed groove 40a and the recessed groove 40a.

On the other hand, a portion of the base material 120 that is pressed by the second convex portion 70 and protrudes into the first concave portion 50 (hereinafter, the second protruding portion 140) has a top surface 71 and a first surface of the second convex portion 70. A compressive load acts on the bottom surface 51 of the recess 50. As a result, the tip portion of the second protruding portion 140 is formed on the bottom portion of the groove portion on the other surface of the separator 20.

As shown in FIG. 4, immediately before the first protruding portion 130 is bent and deformed, the top surface 141 of the second protruding portion 140 is in a state during pressing in which a load is partially applied. Molding of the bottom of the groove of the separator 20 has not been completed. In the press molding of the base material 120, the first protruding portion 130 is first bent and deformed by the compressive load. Subsequently, the entire top surface 141 of the second protrusion 140 is pressed, and the entire top surface 131 of the first protrusion 130 is pressed. In this way, the bottoms of the grooves on both sides of the separator 20 are formed.

The effect of this embodiment will be described.
(1) The fuel cell separator manufacturing apparatus has a first molding having a molding surface 31 in which a pair of first concave portions 50 provided with the first convex portion 40 and the first convex portion 40 interposed therebetween are extended. A mold 30 is provided. Further, a second concave portion 80 provided between each of the pair of second convex portions 70 and the second convex portion 70 facing each of the first concave portions 50 and facing the first convex portion 40 is extended. A second molding die 60 having a molding surface 32 is provided. By pressing the base material 120 with the first molding die 30 and the second molding die 60, a large number of grooves are formed on both sides thereof. The bottom surface 81 of the second concave portion 80 is provided with a ridge 80a extending along the extending direction of the second concave portion 80, and the top surface 41 of the first convex portion 40 faces the ridge 80a. At the same time, a concave groove 40a extending along the extending direction of the first convex portion 40 and having a depth larger than the protruding height of the ridge 80a is provided.

According to such a configuration, since the above-mentioned action is obtained, the bottom portion of the groove portion on one surface of the separator 20 is formed by compression loading, and the groove portion on the other surface is formed by compression loading while using the bending stress associated with bending deformation. It is molded. Therefore, the load required for pressing can be reduced as compared with the case where the bottoms of the grooves on both sides are formed only by compression loading. Therefore, the separator 20 can be molded by one pressing step while suppressing the molding load.

(2) The base material 120 is formed by a compressive load from the top surface 71 of the second convex portion 70 and the bottom surface 51 of the first concave portion 50, while the top surface 41 of the first convex portion 40 and the bottom surface 81 of the second concave portion 80. Prior to molding the base material 120 by a compressive load, bending stress was applied with the ridge 80a as a fulcrum.

According to such a method, the same effect as the above effect (1) can be obtained.
This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

-A coating film containing, for example, conductive particles may be provided on at least one surface of the base material 120 by press molding.
The cross-sectional shapes of the ridge 80a and the concave groove 40a, for example, the width and height (depth) are not limited to those illustrated in the embodiment, and can be changed as appropriate.

-In the present embodiment, the first molding die 30 is moved forward and backward with respect to the second molding die 60, but the second molding die 60 may be moved forward and backward with respect to the first molding die 30. However, they may move forward and backward from each other.

The first molding die 30 may have a convex portion in which the concave groove 40a is not provided, in addition to the first convex portion 40, and the second molding die 60 may have a convex portion in addition to the second concave portion 80. It may have a recess in which the ridge 80a is not provided.

In the present embodiment, as shown in FIG. 5, a part of the first protruding portion 130 of the base material 120 facing the top surface 41 of the first convex portion 40 and the concave portion of the first convex portion 40. A gap 91 is formed between the groove 40a and the groove 40a. For example, the depth of the concave groove 40a can be set so that the above-mentioned part of the first protruding portion 130 is not forged by a compressive load, such as preventing a gap 91 from being generated.

10 ... Single cell, 11 ... Membrane electrode assembly, 12 ... Electrolyte film, 13 ... Catalyst electrode layer, 14 ... Gas diffusion layer, 20 ... Separator, 21 ... Separator, 21a ... 1st groove, 21b ... 2nd groove, 22 ... Separator, 22a ... 1st groove, 22b ... 2nd groove, 30 ... 1st molding mold, 31 ... Molding surface, 32 ... Molding surface, 40 ... 1st convex part, 40a ... Concave groove, 41 ... Top surface, 42 ... Side surface, 43 ... Corner part, 50 ... First concave part, 51 ... Bottom surface, 60 ... Second molding mold, 70 ... Second convex part, 71 ... Top surface, 72 ... Side surface, 80 ... Second concave part, 80a ... Projection Stripes, 81 ... bottom surface, 90 ... relief part, 91 ... gap, 100 ... stack, 120 ... base material, 130 ... first protrusion, 131 ... top surface, 140 ... second protrusion, 141 ... top surface.

Claims (2)

A first molding die having a molding surface formed by extending a first convex portion and a pair of first concave portions provided so as to sandwich the first convex portion, and a pair of first molds facing each of the first concave portions. A second molding die provided between each of the two convex portions and the second convex portion and having a molding surface in which a second concave portion facing the first convex portion is extended, respectively, is provided. A device for manufacturing a separator for a fuel cell, which forms a large number of grooves on both sides of a metal plate by pressing a metal plate material with a 1-mold mold and the 2nd mold.
A ridge extending along the extending direction of the second recess is provided on the bottom surface of the second recess.
On the top surface of the first convex portion, a concave groove facing the ridge and extending along the extending direction of the first convex portion and having a depth larger than the protruding height of the ridge is formed. It is provided ,
The internal angle of the second convex portion, which is the inclination angle of the side surface of the second convex portion with respect to the bottom surface of the second concave portion, is the inclination angle of the side surface of the first convex portion with respect to the bottom surface of the first concave portion. A relief portion that is larger than the internal angle of the convex portion and forms a gap between the metal plate material and the side surface of the second convex portion when the first molding die and the second molding die are combined. A device for manufacturing a fuel cell separator, which is provided in the second molding mold, and the length of the relief portion in the width direction of the first convex portion is reduced toward the top surface of the second convex portion. A first molding mold in which a first convex portion and a pair of first concave portions provided so as to sandwich the first convex portion are extended, a pair of second convex portions facing each of the first concave portions, and the said. By pressing the metal plate material with the second molding die provided between each of the second convex portions and extending the second concave portions facing the first convex portions, a large number of grooves are formed on both sides thereof. It is a method of manufacturing a separator for a fuel cell that forms
A ridge extending along the extending direction of the second recess is provided on the bottom surface of the second recess.
On the top surface of the first convex portion, a concave groove facing the ridge and extending along the extending direction of the first convex portion and having a depth larger than the protruding height of the ridge is formed. It is provided,
The top surface of the second convex portion and the bottom surface of the first concave portion form the metal plate material by a compressive load, while the top surface of the first convex portion and the bottom surface of the second concave portion compress the metal plate material. Prior to molding by, bending stress is applied with the ridge as a fulcrum.
A method for manufacturing a separator for a fuel cell.

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