JP2005243293A - Solid polymer electrolyte membrane for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid polymer electrolyte membrane for a fuel cell capable of simplifying fabrication of the fuel cell by improving its handleability as a simple body and through it. <P>SOLUTION: This solid polymer electrolyte membrane 20 for a fuel cell is used in manufacturing the fuel cell while being sequentially paid out from a state wound in rolled form. The solid polymer electrolyte membrane includes swollen parts 23 respectively formed on a pair of edge sides 20a nearly parallel with the paying-out direction (X-direction), and each having a thickness larger than that of a body part 22 forming an area interlaid between a pair of electrodes. The swollen parts provide the body part with shape holding force for preventing the body part from curling up in the paying-out direction by curling tendency. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a solid polymer electrolyte membrane for a fuel cell that is used while being sequentially drawn out from a state of being wound into a roll during the production of the fuel cell.

  For example, a single cell of a polymer electrolyte fuel cell is configured such that a solid polymer electrolyte membrane as a cation exchange membrane is sandwiched between a pair of electrodes, and the outside is sandwiched between a pair of separators (for example, patents). Reference 1). The solid polymer electrolyte membrane is formed in a thin film in order to suppress a voltage drop due to its resistance. A solid polymer electrolyte membrane, which is a thin film, has poor handling properties because it has little force to retain its shape.

  In Patent Document 1, a solid polymer electrolyte membrane sandwiched between a pair of electrodes is further surrounded by a porous reinforcing member to constitute an integrated electrode. The whole of the plurality of parts improves the handling property of the solid polymer electrolyte membrane.

However, in Patent Document 1, the handling property of the solid polymer electrolyte membrane alone is not considered, and the deformation of the solid polymer electrolyte membrane alone cannot be sufficiently suppressed.
JP 2003-142127 A

  The present invention has been made in order to solve the problems associated with the above-described prior art, and has excellent handling properties as a single unit. Through this, the solid for a fuel cell can simplify the production of the fuel cell. An object is to provide a polymer electrolyte membrane.

In order to achieve the above object, the present invention provides a solid polymer electrolyte membrane for a fuel cell that is used while being fed out from a state wound in a roll shape in the production of a fuel cell.
Including a bulging portion that is provided on each of a pair of edges substantially parallel to the feed-out direction and has a size larger than a thickness of a main body portion that forms an area interposed between the pair of electrodes;
The bulging portion is a solid polymer electrolyte membrane for a fuel cell, which imparts a shape retention force to the main body portion to prevent the main body portion from being rounded in the feed-out direction due to a curl.

  According to the present invention, since the main body portion is prevented from being rounded in the feeding direction by the shape holding force applied from the bulging portion, the solid polymer electrolyte membrane holds the flat shape which is the original shape. In addition, the handling property by itself becomes good. Through this, the manufacture of the fuel cell can be simplified.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a single cell 10 of a solid polymer fuel cell to which a solid polymer electrolyte membrane 20 for a fuel cell according to an embodiment of the present invention is applied. FIG. 2A is a perspective view showing a state in which the solid polymer electrolyte membrane 20 wound in a roll shape is unwound in the production of a fuel cell, and FIG. 2B is a view in FIG. It is sectional drawing which follows the 2B-2B line. 2A indicates the feeding direction of the solid polymer electrolyte membrane 20 fed out from the rolled state, and the Y axis indicates a direction orthogonal to the feeding direction (X direction). Is shown.

  A fuel cell is used in the form of a fuel cell stack in which a large number of single cells 10 are stacked, for example, as a driving source for an automobile.

  The single cell 10 is a battery that can obtain electricity in the process of obtaining water by reacting hydrogen and oxygen by utilizing the reverse principle of electrolysis of water. The single cell 10 includes a solid polymer electrolyte membrane 20 as a cation exchange membrane, a pair of electrodes 31 and 32 on which a catalyst layer is formed, and a pair of separators 41 and 42. The single cell 10 is configured such that the solid polymer electrolyte membrane 20 is sandwiched between a pair of electrodes 31 and 32 and the outside is sandwiched between a pair of separators 41 and 42. The separator 41 on the electrode 31 side is formed with a channel groove 43 for circulating cooling water and a channel groove 44 for circulating fuel gas (hydrogen). In the separator 42 on the electrode 32 side, a channel groove 45 for circulating cooling water and a channel groove 46 for circulating oxidant gas (air) are formed. The shape and arrangement of the channel grooves 43 to 46 need to consider gas diffusibility, pressure loss, discharge of generated water, cooling performance, and the like, and have a fine and complicated configuration.

  The solid polymer electrolyte membrane 20 is a polymer membrane having a function of moving hydrogen ions. The solid polymer electrolyte membrane 20 is formed in a thin film (for example, about several tens of μm to 100 μm) in order to suppress a voltage drop due to its resistance.

  As shown in FIG. 2 (A), the formed solid polymer electrolyte membrane 20 is stored or stored in a state of being wound around a core material 21 in a roll shape, and is used while being fed out sequentially when manufacturing a fuel cell. It is provided.

  As shown in FIG. 2B, the solid polymer electrolyte membrane 20 is provided on each of the pair of edges 20a substantially parallel to the feeding direction (X direction), and between the pair of electrodes 31 and 32. The bulging part 23 which has a dimension larger than the thickness dimension of the main-body part 22 which makes | forms the area | region interposed in is included. The bulging part 23 of the example of illustration is provided in the edge part of the edge 20a, and has cross-sectional circular shape. When assembling the unit cell 10, the main body portion 22 is sandwiched between the pair of electrodes 31 and 32, and the bulging portion 23 protrudes from the electrodes 31 and 32 and is disposed between the pair of separators 41 and 42. (See FIG. 1). The height h of the bulging portion 23 from the surface of the main body portion 22 is set to be larger than the thickness of each electrode 31, 32. Although it mentions later, it is for making the bulging part 23 exhibit a gas seal function.

  The bulging portion 23 imparts to the main body portion 22 a shape retention force that prevents the main body portion 22 from being rounded in the feeding direction (X direction) due to the curl. That is, while the solid polymer electrolyte membrane 20 is stored in a state of being wound in a roll shape, the main body portion 22 is likely to be curled. For this reason, when the solid polymer electrolyte membrane 20 is unwound, a force that tends to round in the unwinding direction (X direction) acts on the main body portion 22 due to the curl. On the other hand, since the bulging portion 23 has a size larger than the thickness of the main body portion 22, the bulging portion 23 is less likely to be curled compared to the main body portion 22 and tries to maintain a flat shape that is the original shape. Strong force, that is, shape retention. When the solid polymer electrolyte membrane 20 is drawn out, the bulging portion 23 imparts a shape retention force to the main body portion 22. As a result, the main body 22 is prevented from curling in the feed-out direction (X direction) against the curving force acting on the main body 22.

  FIG. 3 is a view showing a forming apparatus 50 for forming the solid polymer electrolyte membrane 20 having the bulging portion 23.

  The bulging portion 23 is preferably formed integrally with the main body portion 22 from the same material as that constituting the main body portion 22. This is because the solid polymer electrolyte membrane 20 including the bulging portion 23 can be easily formed.

  The forming apparatus 50 includes an upper roller 51 and a lower roller 52, and small diameter portions 51 a and 52 a for forming the main body portion 22 and a bulging portion 23 are formed in each of the rollers 51 and 52. Annular grooves 51b and 52b having a semicircular cross section are formed. By passing the material of the solid polymer electrolyte membrane 20 between the upper and lower rollers 51 and 52 pressed against each other as indicated by arrows, the main body portion 22 and the bulging portion 23 are integrally formed from the same material. The formed solid polymer electrolyte membrane 20 is molded.

  FIGS. 4A to 4E are conceptual diagrams for explaining a procedure for further forming the reinforcing portion 24 on the solid polymer electrolyte membrane 20 including the bulging portion 23. In FIG. 4, the bulging portion 23 and the reinforcing portion 24 are shown separated from the edges 20 a and 20 b for easy understanding.

  The solid polymer electrolyte membrane 20 is provided on each of the pair of edges 20b substantially parallel to the direction (Y direction) orthogonal to the feeding direction (X direction) and is larger than the wall thickness of the main body 22. Further including a reinforcing portion 24 having The reinforcing portion 24 in the illustrated example is provided on both surfaces of the edge 20b and has a semicircular cross section (see FIG. 4C). When assembling the unit cell 10, the reinforcing portion 24 protrudes from the electrodes 31 and 32 and is disposed between the pair of separators 41 and 42, similarly to the bulging portion 23. The height h of the reinforcing portion 24 from the surface of the main body portion 22 is set to be larger than the thickness of each of the electrodes 31 and 32. Although mentioned later, it is for making the reinforcement part 24 exhibit a gas seal function.

  The reinforcing portion 24 imparts a shape holding force to the main body portion 22 that prevents the main body portion 22 from curling in a direction (Y direction) substantially orthogonal to the feeding direction (X direction). That is, since the thin main body portion 22 has almost no force for holding the shape, the thin body portion 22 may be rounded in a direction (Y direction) perpendicular to the feeding direction (X direction). On the other hand, since the reinforcing portion 24 has a size larger than the thickness of the main body portion 22, compared with the main body portion 22, the force for holding the flat shape, which is the original shape, that is, the shape holding force. strong. When the solid polymer electrolyte membrane 20 is unwound, the reinforcing portion 24 imparts a shape retention force to the main body portion 22. As a result, the main body 22 is prevented from being rounded in a direction (Y direction) substantially orthogonal to the feeding direction (X direction).

  The reinforcing portion 24 is formed from a material different from the material constituting the main body portion 22. This is because a material suitable for the function of the reinforcing portion 24 and a material suitable for the molding method of the reinforcing portion 24 can be freely selected. The material for forming the reinforcing portion 24 is not particularly limited, and for example, silicon rubber that can be injection-molded and can be elastically deformed can be suitably used.

  Referring to FIG. 4, a molding apparatus for molding reinforcing portion 24 includes a molding die 55 for injection molding the material of reinforcing portion 24, and a cutter 56 for cutting solid polymer electrolyte membrane 20 to a predetermined length. Have. In the molding die 55, the reinforcing portion 24 is injection-molded on each of the pair of edges 20b substantially parallel to the Y direction.

  When molding the reinforcing portion 24, first, the fed solid polymer electrolyte membrane 20 is carried into the molding die 55 (FIG. 4A). The main body portion 22 is prevented from being rounded in the feeding direction (X direction) by the shape holding force applied from the bulging portion 23. For this reason, the fed solid polymer electrolyte membrane 20 can be easily carried into the molding die 55. Next, the reinforcing portion 24 is formed by injection molding the material of the reinforcing portion 24 (FIGS. 4B and 4C). And the solid polymer electrolyte membrane 20 is cut | disconnected by predetermined length with the cutter 56 (FIG.4 (D)).

  The rectangular cut piece 25 is provided with a bulging portion 23 on each of a pair of edges 20a substantially parallel to the X direction, and a reinforcing portion 24 is provided on each of the pair of edges 20b substantially parallel to the Y direction. (FIG. 4E). The cut piece 25 is prevented from being rounded in the X direction by the shape holding force applied by the bulging portion 23, and is prevented from being rounded in the Y direction by the shape holding force provided by the reinforcing portion 24. Holds the shape. Therefore, the handleability of the solid polymer electrolyte membrane 20 alone becomes good, and it becomes easy to perform the joining operation with the electrodes 31 and 32 and the assembling operation with the separators 41 and 42 performed thereafter.

  With reference to FIG. 1, in the solid polymer electrolyte membrane 20 of the present embodiment, the bulging portion 23 constitutes a sealing means 26 between the separators 41 and 42. The bulging portion 23 is elastically deformed by a pair of separators 41 and 42 being pressed against each other at portions protruding from the electrodes 31 and 32. Similarly, in the solid polymer electrolyte membrane 20 of the present embodiment, the reinforcing portion 24 also constitutes a sealing means between the separators 41 and 42. In the reinforcing portion 24, the pair of separators 41 and 42 are pressed against each other at the portions protruding from the electrodes 31 and 32, and are elastically deformed.

  Gas sealing is performed when the bulging portion 23 and the reinforcing portion 24 are in pressure contact with the separators 41 and 42. In order to seal the solid polymer electrolyte membrane 20 since the members (the bulging portion 23 and the reinforcing portion 24) that enhance the handling performance of the single polymer electrolyte membrane simultaneously function to seal the gas flowing through the flow channel grooves 44 and 46. Compared with a mode in which only the members are separately provided, the number of parts can be reduced and the manufacturing process can be simplified.

  As described above, according to the present embodiment, in the solid polymer electrolyte membrane 20 for a fuel cell that is used while being sequentially fed out from a state wound in a roll during the production of the fuel cell, the feeding direction (X And a bulge having a dimension larger than the wall thickness of the main body 22 that is provided on each of the pair of edges 20a substantially parallel to the direction) and that is interposed between the pair of electrodes 31 and 32. The bulging portion 23 includes a portion 23, and the bulging portion 23 imparts a shape holding force to the main body portion 22 to prevent the main body portion 22 from being rounded in the feeding direction (X direction) due to the curl so that the solid polymer electrolyte membrane 20 is The flat shape, which is the original shape, is maintained, and the handling property by itself is good. Through this, the manufacture of the fuel cell can be simplified.

  It further includes a reinforcing portion 24 provided on each of the pair of edges 20b substantially parallel to the direction (Y direction) orthogonal to the feeding direction (X direction) and having a size larger than the thickness of the main body portion 22. The reinforcing portion 24 gives the main body portion 22 a shape holding force that prevents the main body portion 22 from curling in a direction (Y direction) substantially orthogonal to the feeding direction (X direction). Further, the flat shape, which is the original shape, is further maintained, and the handling property as a single unit is further improved. Through this, the manufacture of the fuel cell can be simplified.

  Since the bulging portion 23 is formed integrally with the main body portion 22 from the same material as that constituting the main body portion 22, the solid polymer electrolyte membrane 20 including the bulging portion 23 can be easily formed. .

  Since the reinforcing part 24 is formed of a material different from the material constituting the main body part 22, a material suitable for the function of the reinforcing part 24 and a material suitable for the molding method of the reinforcing part 24 can be freely selected.

  Since the bulging part 23 constitutes a sealing means 26 between the separators 41 and 42 and the reinforcing part 24 constitutes a sealing means between the separators 41 and 42, the solid polymer electrolyte membrane 20 alone Since the members (the bulging portion 23 and the reinforcing portion 24) that improve the handleability at the same time exert the function of sealing the gas, the number of parts can be reduced compared to a configuration in which a member only for sealing is separately provided. Reduction and simplification of the manufacturing process can be achieved.

(Modification)
FIGS. 5A to 5C are diagrams showing a modification of the shape of the bulging portion 23.

  The bulging part 23 can adopt an appropriate shape in consideration of the rounding prevention function and the gas sealing function of the main body part 22. For example, a form in which the bulging part 23 is formed in a double manner with a slight gap (FIG. 5A), a form in which the bulging part 23 having a rectangular cross section is formed (FIG. 5B), two pieces The form (FIG.5 (C)) etc. which form the double clip formed by connecting the bulging part 23 can be illustrated. Similarly, an appropriate shape can be adopted for the reinforcing portion 24 in consideration of the rounding prevention function and the gas sealing function of the main body portion 22.

  The protruding portion of the solid polymer electrolyte membrane 20 that protrudes from the electrodes 31 and 32 is located at a substantially central portion between the pair of separators 41 and 42. For this reason, when forming the bulging part 23 and the reinforcement part 24 which also have a gas seal function, it is preferable that the cross-sectional shape of the bulging part 23 and the reinforcement part 24 is a symmetrical shape centering | focusing on the main-body part 22. FIG. . This is for ensuring a uniform pressing force between the separators 41 and 42. When the thickness dimensions of the electrodes 31 and 32 are different, the cross-sectional shapes of the bulging portion 23 and the reinforcing portion 24 may be asymmetrical about the main body portion 22 in order to ensure a uniform pressing force. .

  In addition, although the bulging part 23 and the reinforcement part 24 provided with a gas seal function were demonstrated, it is good also as the bulging part 23 and the reinforcement part 24 provided only with the curling prevention function of the main-body part 22. FIG. In this case, the bulging portion 23 and the reinforcing portion 24 can be formed only on either the front surface or the back surface of the main body portion 22.

  The present invention can be applied to uses for producing a solid polymer electrolyte membrane for a fuel cell.

FIG. 1 is a cross-sectional view showing a single cell of a polymer electrolyte fuel cell to which a solid polymer electrolyte membrane for a fuel cell according to an embodiment of the present invention is applied. FIG. 2 (A) is a perspective view showing a state in which the solid polymer electrolyte membrane wound in a roll shape is drawn out during the production of a fuel cell, and FIG. 2 (B) is a diagram of FIG. 2 (A). It is sectional drawing which follows the 2B-2B line. It is a figure which shows the shaping | molding apparatus which shape | molds a solid polymer electrolyte membrane provided with a swelling part. FIGS. 4A to 4E are conceptual diagrams for explaining a procedure for further forming a reinforcing portion on a solid polymer electrolyte membrane having a bulging portion. FIGS. 5A to 5C are diagrams showing a modification of the shape of the bulging portion.

Explanation of symbols

10 single cell,
20 solid polymer electrolyte membrane,
20a A pair of edges substantially parallel to the feeding direction,
20b A pair of edges substantially parallel to the direction orthogonal to the feeding direction,
21 Core material,
22 body part,
23 bulges,
24 reinforcements,
25 cut pieces,
26 sealing means,
31, 32 electrodes,
41, 42 separator,
50 molding equipment,
51 Upper roller,
51a, 52a small diameter part,
51b, 52b annular groove,
52 Lower roller,
55 Mold,
56 cutters,
X The feeding direction of the solid polymer electrolyte membrane,
Y A direction perpendicular to the feeding direction (X direction).

Claims (6)

In the solid polymer electrolyte membrane for a fuel cell to be used while being sequentially drawn out from a state wound in a roll during the production of the fuel cell,
Including a bulging portion that is provided on each of a pair of edges substantially parallel to the feed-out direction and has a size larger than a thickness of a main body portion that forms an area interposed between the pair of electrodes;
A solid polymer electrolyte membrane for a fuel cell, wherein the bulging portion imparts a shape holding force to the main body portion to prevent the main body portion from being rounded in the feeding direction due to a curl. A reinforcing portion provided on each of a pair of edges substantially parallel to the direction orthogonal to the feeding direction, and having a size larger than the thickness of the main body portion;
2. The solid height for a fuel cell according to claim 1, wherein the reinforcing portion imparts a shape holding force to the main body portion to prevent the main body portion from being rounded in a direction substantially orthogonal to the feeding direction. Molecular electrolyte membrane.   2. The solid polymer electrolyte membrane for a fuel cell according to claim 1, wherein the bulging portion is formed integrally with the main body portion from the same material as that constituting the main body portion.   3. The solid polymer electrolyte membrane for a fuel cell according to claim 2, wherein the reinforcing portion is made of a material different from a material constituting the main body portion.   2. The solid polymer electrolyte membrane for a fuel cell according to claim 1, wherein the bulging portion constitutes a sealing means between the separator and the separator.   3. The solid polymer electrolyte membrane for a fuel cell according to claim 2, wherein the reinforcing portion constitutes a sealing means between the separator and the separator.

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