JP4482414B2 - Unit fuel cell - Google Patents

Description

  The present invention relates to a unit fuel cell comprising an electrode membrane structure and a pair of separators sandwiching the electrode membrane structure in a polymer electrolyte fuel cell.

Conventionally, a method of manufacturing a unit fuel cell that includes an electrode membrane structure and a pair of separators that sandwich the electrode membrane structure has been proposed (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 2002-246044 (FIG. 5)

Patent document 1 is demonstrated based on the following figure.
FIG. 12 is a diagram for explaining the basic configuration of the prior art, in which a membrane electrode film structure 103 is arranged between two separators 101 and 102 to which a liquid seal has been applied in advance, and holding jigs 104 and 105 are arranged from above and below. And put in an oven or the like to heat, cure the liquid seal, and temporarily assemble the unit fuel cell. At this time, in order to position the membrane electrode film structure 103 with respect to the separators 101 and 102, clips 106 and 106 that support the edge of the membrane electrode film structure 103 are used.

  However, since the clips 106 and 106 are attached manually, the clips 106 and 106 are attached to the edge of the membrane electrode membrane structure 103, which requires man-hours. In addition, when assembling a stack with a plurality of unit fuel cells, there is a problem that the unit fuel cells are scattered.

  Then, this invention makes it a subject to provide the unit fuel cell which can fix a separator and a polymer electrolyte membrane, without using a clip.

  According to the first aspect of the present invention, a pair of separators are formed by integrally forming a sealing material on the edge of the separator body, a plate-like electrode film structure is placed on one separator, and the other electrode film structure is placed on the other electrode film structure. In the unit fuel cell on which the separator is mounted and the sealing material ensures airtightness, the edge of the separator body is a U-shaped cross-section piece that can be attached to the separator body by fitting, and a resin formed by injection molding Material, one U-shaped cross-section piece is composed of a non-translucent thermoplastic resin material, the other U-shaped cross-section piece is composed of a translucent thermoplastic resin material, and the U-shaped cross-section pieces overlap each other. The laser beam that has passed through the other U-shaped cross-section piece is joined by melting and solidifying the boundary between the U-shaped cross-section pieces.

In the invention according to claim 1, a pair of separators sandwiching the electrode membrane structure is arranged, and the edges of the separator main body covered with these separators can be attached to the separator main body by fitting; And a resin material formed by injection molding, one U-shaped cross-section piece is composed of a non-translucent thermoplastic resin material, and the other U-shaped cross-section piece is composed of a translucent thermoplastic resin material.
Because the U-shaped cross piece is sandwiched between the edges of the separator body, even when the separator is warped, swelled, or distorted when molding the unit fuel cell, correct it and suppress the occurrence of seal film defects There is an advantage that can be.

Then, the separators were overlapped, a laser beam was applied to the U-shaped cross-sectional piece, and the boundary part between the separators was melted and solidified to be joined.
Since the laser beam passes through a transparent member such as an acrylic plate, when a transparent holding member is placed on the seal material, the U-shaped cross-section pieces are easily pressed by the weight of the holding member, and from above. It can be easily joined by applying a laser beam.

By placing the pressing member on the sealing material, the separator can be brought into close contact with the electrode film structure without using a holding jig such as a clip and can be easily joined with a laser beam.
As a result, there is an advantage that the number of assembling steps can be reduced because the operation can be easily performed.
In addition, since the separators can be firmly joined by a laser beam, there is no problem that the joined separators are scattered in the step of laminating unit fuel cells.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.

  FIG. 1 is a diagram for explaining the fitting of a U-shaped cross-section piece to the edge of the separator body. A U-shaped cross-section piece 61 having a height H is prepared in the separator body 11. And it shows fitting the prepared U-shaped cross-section piece 61 to the edge 66 of the separator main body 11.

FIG. 2 is a cross-sectional view of the main part of the separator before the U-shaped cross-section piece according to the present invention is arranged and the sealing material is integrally formed. The separator main body 11 with the U-shaped cross-section piece 61 attached to the lower mold 62 is set. The upper mold 64 is covered.
Next, a molten sealing material is injected into the cavities 63 and 65 of the injection mold 60 to integrally mold the sealing material on the separator body 11.

  FIG. 3 is a completed view of the separator according to the present invention. The separator 15 has a U-shaped cross-section piece 61 having a height corresponding to the total vertical height H of the sealing material 14 fitted to the edge 66 of the separator body 11. After the separator body 11 with the U-shaped cross-section piece 61 is set in the injection mold 60, the molten sealing material is injected into the cavities 63 and 65 of the injection mold 60. Then, the mold body is opened and the separator body 11 with the sealing material 14 and the U-shaped cross-section piece is opened and the upper mold 64 is opened.

  By setting the U-shaped cross-section piece 61 on the edge 66 of the separator body 11, even if the separator body 11 is warped, swelled or distorted, it is possible to correct them and suppress the occurrence of sealing film defects. it can. As a result, the separator 15 without distortion can be obtained.

In addition, since the upper and lower surfaces 12 and 13 of the separator main body 11 can be simultaneously held by the U-shaped cross-sectional piece 61, it is possible to save the trouble of holding the upper and lower surfaces individually in order to correct the distortion of the separator main body 11.
As a result, the manufacturing cost can be reduced.

The injected molten sealing material 14 is silicone rubber, and the U-shaped cross-section piece 61 is a member containing silicon or a silicon compound.
Since silicon or a silicon compound is contained in the U-shaped cross-sectional piece 61, the same component as that of the sealing material, which is a liquid rubber to be injection-molded, is included. can get.
By the above manufacturing method, the fuel cell separator 15 including the sealing material 14 on the upper and lower surfaces 12 and 13 of the edge 66 of the separator body 11 can be manufactured.

  Even if the U-shaped cross-section piece 61 is fitted to the edge 66 of the separator body 11 and the U-shaped cross-section piece 61 is molded so as to be embedded in the sealing material 14, even if the separator is warped, swelled or distorted, They can be corrected and the occurrence of sealing film defects can be suppressed.

  FIG. 4 is a diagram for preparing a separator and an electrode film structure according to the present invention, and the dimension G of the cross-sectional shape of the seal surface is zero because of sandwiching the plate-like electrode film structure. It shows that a separator, a separator secured by the thickness Gb of the electrode film structure, and a separator having two types of specifications are prepared.

FIG. 5 is a cross-sectional view of the principal part of the unit fuel cell showing that the U-shaped cross-section pieces are joined together with a laser beam in a state where the upper and lower sides of the electrode membrane structure according to the present invention are sandwiched between sealing members formed integrally with the separator body. It indicates that the boundary portion between the separators is joined with a laser beam.
On the base jig 56 serving as a base, one separator 15 prepared in FIG. 4, the electrode film structure 55, and the other separator 15 are placed in order, and from above, a translucent member such as an acrylic plate, for example. 57, and the electrode film structure 55 is sandwiched between the sandwiching surfaces 58 of the separator, embedded in the lower surface of one separator 15, and one U-shaped cross-sectional piece 61 formed of the non-translucent thermoplastic resin material 25; The other U-shaped cross-section piece 61 embedded in the upper surface of the other separator 15 and formed of the translucent thermoplastic resin material 24 is brought into close contact with the other separator 15. Then, the laser beam L is applied to the edge portion, and the boundary portion 22 is melted and solidified to be joined.

  That is, the sealing material 14 is composed of a U-shaped cross-section piece 61 that can be attached to the edge of the separator body 11 by fitting, and a resin material 71 formed by injection molding, and one U-shaped cross-section piece 61 is not transparent. The U-shaped cross-section piece 61 is composed of the light-type thermoplastic resin material 25, the other U-shaped cross-section piece 61 is composed of the light-transmitting thermoplastic resin material 24, and the U-shaped cross-section pieces 61, 61 are overlapped with each other. The boundary portion 22 between the U-shaped cross-section pieces 61 and 61 is melted and solidified by the laser beam that has passed therethrough.

Since the laser beam L passes through a translucent member 57 such as an acrylic plate, when the translucent member 57 is placed on the U-shaped cross-section piece 61, the sealing material is caused by its own weight. 14 can be pressed and brought into close contact with each other, and can be easily fixed by applying a laser beam L thereto.
As a result, the separator 15 can be brought into close contact with the electrode film structure 55 and can be joined by the laser beam L without using a holding jig such as a clip. Since there is no need to set the holding jig and the work can be performed easily, there is an advantage that the number of assembling steps can be reduced.

In addition, since the separators 15 can be firmly bonded to each other, there is no possibility that the bonded separators 15 are separated in the step of stacking the unit fuel cells 23.
Further, the edge 66 of the separator body 11 is sandwiched between the U-shaped cross-section pieces 61.
Since the U-shaped cross-section piece 61 is sandwiched between the edge 66 of the separator body 11, even when the separator 15 is warped, swelled or distorted when the unit fuel cell 23 is molded, the separator 15 is corrected and the sealing material film The occurrence of defects can be suppressed.

In the present embodiment, a diode laser is used as the laser beam generator, but it may be a YAG laser or a carbon dioxide gas laser, and is not limited to that type.
Further, the wavelength of the laser beam is determined based on the trade-off between the translucency of the resin on the other side and the running cost.

FIG. 6 is a completed view of a unit fuel cell according to the present invention. The unit fuel cell 23 can be manufactured by solidifying.
Unit fuel cells 23 are formed, and by stacking these unit fuel cells 23, a fuel cell stack free from erroneous assembly can be easily manufactured.

  Further, since the separators 15 can be firmly bonded by the laser beam L, there is no possibility that the bonded separators 15 are separated in the step of stacking the unit fuel cells 23.

FIG. 7 is an explanatory view of injection molding according to another embodiment.
(A) is a figure which shows setting the separator main body provided with the spherical holding member 16 to the injection mold, and setting the separator main body 11 with the spherical holding member 16 attached to the first lower mold 42, Place the mold 43. The upper mold 43 is provided with gates 44 and 45 for injecting molten sealing material, and injected from a cylinder (not shown) for supplying the molten sealing material to the gates 44 and 45 via runners 46 and 47 serving as supply paths. It is a mold that can do.
When the upper mold 43 is aligned with the first lower mold 42 and the injection mold 41 is closed, the spherical holding member 16 attached to the separator body 11 contacts the cavity 51 of the upper mold 43.

In (b), a molten sealing material is injected into the cavity 51 through the gate 44 using a cylinder (not shown). When the sealing material is solidified, the first lower mold 42 is removed from the upper mold 43.
In (c), the second lower mold 54 is aligned with the upper mold 43.

At this time, since the holding member 16 attached to the separator body 11 is brought into contact with the cavity 51 of the upper mold 43 and the separator body 11, the separator body 11 is not warped, swelled, or distorted.
As a result, a separator 15 in which the sealing material 14 is coated to a certain thickness can be obtained.

The sealing material 14 is silicone rubber, and the holding member contains silicon or a silicon compound.
Since silicone rubber is used as the sealing material, effects of insulation, heat resistance, water repellency, aging resistance and chemical resistance can be obtained.

In addition, since the spherical holding member 16 contains silicon or a silicon compound, the spherical holding member 16 contains the same components as the silicone rubber that is the sealing material to be injection-molded, and between the sealing material 14 and the holding member 16. A preferred bond is obtained.
In addition, after the spherical holding member 16 is arranged, a primer containing silicon or a silicon compound is applied to the surface of the spherical holding member 16 and injection molding of the molten sealing material is performed, so that the sealing material 14 and the spherical holding member 16 are further spherical. It is also possible to improve the bonding with the holding member 16.

  6D is a view showing a state in which a molten sealing material is injected into the cavity 52 of the second lower mold 54 from another gate 45 provided in the upper mold 43, and the second lower mold 54 is aligned with the upper mold 43; A molten sealing material is injected into the cavity 52 through the gate 45 using a cylinder (not shown).

  By injecting the molten sealing material into the cavity 52 from the gate 45, even if warpage, undulation, distortion, and the like are generated, they can be corrected and the occurrence of sealing film defects can be suppressed.

The separator body 11 integrally formed with the seal material 14 requires a pair of two members per unit fuel cell.
Accordingly, the dimension G of the cross-sectional shape of the sealing surface is such that the separator 15 having a dimension G of zero and the separator 15 secured by the thickness of the electrode film structure are in relation to sandwiching the plate-like electrode film structure. Two types of separators are required, and in this example, the process of forming a separator having a specification in which only the thickness Ga of the electrode film structure is secured is shown.

  FIG. 8 is a diagram showing another embodiment of FIG. 3. A spherical holding member 16 is attached to a part of the separator main body 11, and the spherical holding member 16 is molded so as to be embedded in the sealing material 14. Even if waviness and distortion occur, they can be corrected and occurrence of sealing film defects can be suppressed.

  FIG. 9 is a diagram showing another embodiment of FIG. 4. As described above, the dimension G of the cross-sectional shape of the seal surface is the separator 14 having a dimension G of zero because the plate-like electrode film structure is sandwiched. And a separator having a thickness Ga of the electrode film structure and a separator having two types of specifications are prepared.

  FIG. 10 is a diagram showing another embodiment of FIG. 5. On the base jig 56 serving as a base, one separator 15 prepared in FIG. 9, the electrode film structure 55, and the other separator 55 are placed. From above, a translucent member 57 such as an acrylic plate is placed, and the lower surface 21a of the separator and the upper surface 21b of the separator are brought into close contact with the electrode film structure 55 sandwiched between the sandwiching surfaces 58 and 58 of the separator. Then, the laser beam L is applied to the edge portion, and the boundary portion 21 is melted and solidified to be joined.

  That is, a pair of separators 15 is formed by integrally forming the sealing material 14 on the edge 11 a of the separator body 11, and a plate-like electrode film structure 55 is placed on one separator 15, and the other electrode film structure 55 is placed on the other electrode film structure 55. In a set of three unit fuel cells 23 in which the separator 15 is mounted and the sealing member 14 ensures airtightness, the sealing member 14 formed on one separator 15 is replaced by a translucent thermoplastic resin material 24. The sealing material 14 formed on the other separator 15 is constituted by a non-translucent thermoplastic resin material 25, the separators 15 are overlapped with each other, and the laser beam L passed through the one separator 15 The boundary portion 22 is joined by melting and solidifying.

Since the laser light L is transmitted through a translucent member 57 such as an acrylic plate, when the translucent member 57 is placed on the seal member 14, the sealing material can be easily formed by its own weight. It can be easily joined by pressing 14, 14 and applying the laser beam L from above.
By placing the translucent member 57 on the sealing material 14, the separator 15 can be brought into close contact with the electrode film structure 55 without using a holding jig such as a clip and can be easily joined with the laser beam L. it can. As a result, the manufacturing cost for assembly can be reduced.

  FIG. 11 is a diagram showing another embodiment of FIG. 6. A unit fuel cell 23 can be manufactured by overlapping the sealing materials 14, applying a laser beam L, and melting and solidifying the boundary 22 between the separators 15. .

Unit fuel cells 23 are formed, and by stacking these unit fuel cells 23, a fuel cell stack free from erroneous assembly can be easily manufactured.
In addition, since the separators 15 can be firmly bonded to each other by a laser beam, the bonded separators 15 are not likely to be separated in the step of stacking the unit fuel cells 23.

  In this embodiment, polyphenylene sulfide (PPS resin) is used as the resin constituting the U-shaped cross-section piece or the spherical holding member, and the light-transmitting thermoplastic resin material is used as it is. As the mold thermoplastic resin material, a material obtained by adding carbon to a PPS resin is used, but the material is not limited to this. For example, nylon, polyacetal, polycarbonate, modified polyphenylene oxide, polybutylene terephthalate, reinforced polyethylene terephthalate, polysulfone, wholly aromatic polyester, polyether ketone, polyimide, polyether imide, etc. can be used.

  The present invention is suitable for a unit fuel cell.

It is a figure explaining fitting a U-shaped cross section piece to the edge of a separator main part. It is principal part sectional drawing of the separator before arrange | positioning the U-shaped cross-section piece which concerns on this invention, and integrally forming a sealing material. It is a completion drawing of the separator concerning the present invention. It is a figure which prepares the separator and electrode film structure which concern on this invention. It is principal part sectional drawing of a unit fuel cell which shows joining a U-shaped cross-section piece with a laser beam in the state clamped by the sealing material integrally formed in the separator main body from the upper and lower sides of the electrode membrane structure which concerns on this invention. FIG. 2 is a completed view of a unit fuel cell according to the present invention. It is explanatory drawing of the injection molding which concerns on another Example. It is another Example figure of FIG. It is another Example figure of FIG. It is another Example figure of FIG. It is another Example figure of FIG. It is a figure explaining the basic composition of the conventional technology.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Separator main body, 11a ... Edge of separator main body, 14 ... Sealing material, 15 ... Separator, 22 ... Boundary part, 23 ... Unit fuel cell, 24 ... Translucent thermoplastic resin material, 25 ... Non-transparent thermoplastic Resin material, 55... Electrode membrane structure, 61.

Claims (1)

A pair of separators are formed by integrally forming a sealing material on the edge of the separator body, a plate-like electrode film structure is placed on one separator, the other separator is placed on this electrode film structure, and the sealing material In a unit fuel cell that is designed to ensure airtightness,
The edge of the separator body is composed of a U-shaped cross-section piece that can be attached to the separator body by fitting, and a resin material formed by injection molding, and one U-shaped cross-section piece is made of a translucent thermoplastic resin material. The other U-shaped cross-section piece is made of a non-transparent thermoplastic resin material, the U-shaped cross-section pieces are overlapped with each other, and the U-shaped cross-section pieces are passed through the laser beam. A unit fuel cell characterized by being joined by melting and solidifying the boundary part.

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