JP2011035289A - Method of manufacturing backside integrated sheet for solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a backside integrated sheet for a solar cell module, capable of preventing warpage of an integrated sheet in manufacturing the integrated sheet while laminating a back sheet and a backside side filler. <P>SOLUTION: In the method of manufacturing a backside integrated sheet for a solar cell module for laminating a back sheet used on the backside of the solar cell module and a filler on the backside, a laminate passed through a laminating process is wound up so that the filler is outside to form a wound body and is preserved as the wound body for a predetermined period. Preferably, the filler is EVA (ethylene-vinyl acetate copolymer), and the laminating method is preferably a molten pressing of the filler onto the back sheet. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a back surface integrated sheet for a solar cell module, and more specifically, a solar cell module in which a back sheet used on the back surface side of a solar cell module and a back surface side filler are laminated in advance. The present invention relates to a method for manufacturing a back surface integrated sheet.

  In recent years, solar cells as a clean energy source have attracted attention due to the growing awareness of environmental issues. In general, in a solar cell module constituting a solar cell, a transparent front substrate, a front surface side filler, a solar cell element, a back side filler, and a back sheet (also referred to as a back surface protective sheet) are sequentially stacked from the light receiving surface side. And has a function of generating electric power when sunlight enters the solar cell element.

  The front surface side filler and the back surface side filler are members provided so as to sandwich the solar cell element from the front surface side and the back surface side of the solar cell element, and function as an adhesive that adheres the solar cell element to other members. It is required to exhibit a function of protecting the solar cell element from external impacts. As such a filler sheet, EVA (ethylene-vinyl acetate copolymer) -based, PVB (polyvinyl butyral) -based, silicone-based resins, and the like have been proposed. The back sheet is a member provided on the back surface of the solar cell module, and is required to have a function of preventing water vapor or the like that affects the solar cell element from entering from the outside of the solar cell module. As such a back sheet, for example, a composite film of a fluororesin film and a metal foil is used.

  Each member of the transparent front substrate, the front side filler, the solar cell element, the back side filler and the backsheet constituting the solar cell module is laminated in this order, for example, a lamination method in which vacuum suction is applied to perform thermocompression bonding. Manufactured using. The members constituting the solar cell module are often stacked manually. In general, since each member constituting the solar cell module has a large area, it is very laborious and labor to manually stack these members. As one method for reducing such labor, it is conceivable to use an integrated sheet in which a plurality of members are laminated in advance (see Patent Document 1).

  For example, if two sheet-like members are laminated in advance to form an integrated sheet, it can be said that there are advantages in terms of reducing the man-hours in manufacturing the solar cell module and simplifying the transportation and management of the members. As a lamination method, conventionally known lamination methods such as a dry lamination method, a melt extrusion method, and a thermal lamination method are known.

JP 2000-91610 A

  However, in these laminating methods, as a problem arising from the difference in shrinkage rate between the respective members to be integrated, there is a warp (curl) of the integrated sheet after lamination. Such a problem of warping of the laminated body usually occurs even in an ordinary laminated packaging material, etc. In particular, each member constituting the solar cell module as described above is usually laminated in a plane by manual work. Is done. And since it is a large area, when an integrated sheet curls, the operation | work which overlaps will become difficult and workability | operativity will fall remarkably. Also, since the filler sheet is usually as thick as several hundred microns, the problem of curling is significant when integrated with the back sheet.

  If the stacking is performed in a state where a large amount of warpage has occurred, naturally the positioning accuracy is likely to be incorrect, and the stacking of modules cannot be performed accurately, and quality problems are likely to occur. In particular, when a module is formed with the end portion of the integrated sheet folded back by mistake, it becomes a fatal problem and greatly affects the product yield.

  Thus, the problem of the warpage of the integrated sheet in the solar cell module member has become a major problem to be solved to the extent that it cannot be compared with other uses.

  The present invention has been made in view of the above situation, and among the members constituting the solar cell module, in particular, when a back sheet and a back side filler are laminated in advance to produce an integrated sheet. An object of the present invention is to provide a method for producing a back surface integrated sheet for a solar cell module that can suppress the warpage of the integrated sheet and can greatly improve the productivity.

  As a result of intensive studies to solve the above problems, the present inventors have found that warping can be suppressed by paying attention to the winding direction immediately after lamination of a long laminate, and have completed the present invention. Specifically, the present invention provides the following.

(1) This invention is a manufacturing method of the back surface integrated sheet for solar cell modules which laminates | stacks the back sheet used for the back surface side of a solar cell module, and the filler of a back surface side,
A laminated body that has undergone a laminating process is wound up so that the filler is on the outside, and is taken up as a wound body, and is stored in a state of the wound body for a certain period of time. It is a manufacturing method.

  (2) Moreover, this invention is a manufacturing method of the back surface integrated sheet for solar cell modules as described in (1) by which the storage in the state of the said winding body is performed at 30-50 degreeC for at least 24 hours or more.

  (3) Moreover, this invention is a back integrated sheet for solar cell modules as described in (1) or (2) in which the said filler mainly contains the ethylene-vinyl acetate copolymer whose vinyl acetate content is 15-45 mass%. It is a manufacturing method.

(4) The solar cell according to (1) or (2), wherein the filler mainly includes a metallocene linear low-density polyethylene having a density in the range of 0.870 to 0.890 g / cm ^3. It is a manufacturing method of the back surface integrated sheet for modules.

  (5) In the solar cell module according to any one of (1) to (4), in the present invention, the stacking step is a step of melting and extruding a resin composition constituting the filler on a back sheet. It is a manufacturing method of a back surface integrated sheet.

  According to the present invention, among the members constituting the solar cell module, in particular, when the back sheet and the back surface side filler are laminated in advance to produce the back surface integrated sheet, the back surface integrated sheet is effectively warped. The manufacturing method of the back surface integrated sheet for solar cell modules which can prevent and can improve productivity and quality significantly can be provided.

It is an expanded sectional view which shows an example of the back surface integrated sheet obtained by the manufacturing method of this invention. It is an expanded sectional view which shows an example of the solar cell module using the back surface integrated sheet of FIG. It is the schematic which shows an example of the lamination | stacking method in the manufacturing method of this invention. It is the schematic which shows the measuring method of the curvature amount of the back surface integrated sheet obtained by the manufacturing method of this invention.

  Hereinafter, an embodiment of a method for producing a back surface integrated sheet for solar cell modules of the present invention (hereinafter also simply referred to as a back surface integrated sheet) will be described.

<Backside integrated sheet>
First, an embodiment of the back integrated sheet of the present invention shown in FIG. 1 will be described. The back surface integrated sheet 1 of the present embodiment is manufactured by one embodiment of the method for manufacturing a back surface integrated sheet of the present invention described later. The back surface integrated sheet 1 of the present invention is formed by joining a back sheet 2 and a back surface side filler 3. Hereinafter, these members will be described. In the solar cell module 10 shown in FIG. 2, the filler 3 (see FIG. 1) included in the back integrated sheet 1 of the present invention and the filler provided between the solar cell element 11 and the transparent front substrate 13. In the following description, the former will be referred to as the back side filler 3 and the latter will be referred to as the front side filler 12, respectively.

[Back sheet]
The back sheet 2 used in the back surface integrated sheet 1 of the present embodiment is also called a back surface protection sheet, and prevents water vapor and gas that adversely affect the solar cell element 11 included in the solar cell module 10 from entering. Provided for. For this reason, it is preferable that the back sheet 2 is formed from a material having a high water vapor barrier property and a high gas barrier property.

  The back sheet 2 is excellent in mechanical or chemical strength, specifically, various fastnesses such as weather resistance, heat resistance, water resistance, light resistance, wind pressure resistance, yield resistance, chemical resistance, and puncture resistance. It is an excellent resin sheet. Examples of such resin sheets include polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, polyvinyl chloride resins, fluorine Resins, poly (meth) acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate, polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyaryls Various resin sheets such as phthalate resin, silicone resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyurethane resin, acetal resin, cellulose resin, etc. It is possible to use.

  Among these resin sheets, in particular, a biaxially stretched polyethylene terephthalate resin, a fluorine resin ETFE (tetrafluoroethylene / ethylene copolymer) or PVDF (polyvinylidene fluoride) film or sheet is preferably used. In this specification, the term “resin sheet” is used as the name of a product obtained by processing these resins into a sheet shape, but this term is used as a concept including a resin film.

  In the present embodiment, as the various resin sheets, for example, one or more of the various resins described above are used, and an extrusion method, a cast molding method, a T-die method, a cutting method, an inflation method, and the like. Examples thereof include those formed by using a film forming method.

  In forming the above-mentioned various resins, for example, sheet processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slip properties, mold release properties, flame retardancy, Various plastic compounding agents, additives and the like can be added for the purpose of improving and modifying moldability, electrical characteristics, strength, colorability and the like.

  The backsheet 2 may have a vapor deposition film of metal or metal oxide, or may be combined with a metal foil in order to impart water vapor barrier properties and gas barrier properties. Further, the back sheet 2 may be a laminate having a plurality of layers made of the above various resin sheets, a resin sheet having a metal or metal oxide film deposition film, a metal foil, or the like.

[Back side filler]
Next, the back surface side filler 3 will be described. The back surface side filler 3 used by the back surface integrated sheet 1 of this embodiment is a member provided so that the solar cell element 11 may be pinched | interposed with the surface side filler 12, and the solar cell element 11 is adhere | attached on another member. In addition to functioning as an adhesive, it functions to protect the solar cell element 11 from external impacts. The back surface side filler 3 has a thermoplastic resin as a main component and is laminated on the surface of the back sheet 2 by a predetermined method.

  The resin constituting the back side filler 3 is not particularly limited, but preferably has thermoplasticity and exhibits flexibility when processed into a sheet shape. Examples of such resins include EVA (ethylene-vinyl acetate copolymer) based resins, PVB (polyvinyl butyral) based resins, silicone based resins, polyethylene based resins, and the like. These resins can be used alone or in combination of two or more depending on the required performance.

As the polyethylene resin, a copolymer of ethylene and α-olefin is preferably used from the viewpoint of imparting flexibility to the back surface side filler sheet 3. An example of such a resin is a metallocene linear low density polyethylene. The metallocene linear low density polyethylene is synthesized using a metallocene catalyst which is a single site catalyst. Such a polyethylene resin has few side chain branches and a uniform distribution of comonomer. For this reason, it can be set as the polyethylene-type resin with narrow molecular weight distribution and a small density, and can provide a softness | flexibility to a sheet | seat. From the viewpoint of suppressing warpage, it is preferably a metallocene linear low density polyethylene having a density in the range of 0.870 to 0.890 g / cm ³ , and the α-olefin has 6 to 8 carbon atoms. Is preferred.

  The polyethylene resin preferably further contains a silane copolymer obtained by copolymerizing an α-olefin and an ethylenically unsaturated silane compound as a comonomer. By using such a resin, adhesiveness between a member such as the solar cell element 11 and the front surface side filler 12 and the back surface side filler 3 can be obtained. A silane copolymer obtained by copolymerizing an α-olefin and an ethylenically unsaturated silane compound as a comonomer is described, for example, in JP-A-2003-46105. By using the copolymer as a component of the back surface side filler 3 of the solar cell module, it is excellent in strength, durability and the like, and also has weather resistance, heat resistance, water resistance, light resistance, wind pressure resistance, and yield resistance. In addition, it is excellent in other aptitudes, and exhibits extremely excellent heat-fusibility without being affected by manufacturing conditions such as thermocompression bonding for manufacturing the solar cell module 10, stably, at low cost, and for various uses. Can be manufactured. Such a silane copolymer is a copolymer obtained by copolymerizing at least an α-olefin and an ethylenically unsaturated silane compound as a comonomer and, if necessary, further using another unsaturated monomer as a comonomer. Furthermore, the modified product or condensate thereof is also included.

  In addition, as resin which comprises the other back surface side filler 3, the resin of EVA (ethylene-vinyl acetate copolymer) type | system | group whose vinyl acetate content is 15-45 mass% is used preferably from a flexible point. The more flexible the material, the smaller the warpage of the integrated sheet. This point will be described in more detail in the embodiments described later.

  The resin mentioned as the resin constituting the back surface side filler 3 is processed into a sheet shape by, for example, a conventionally known extrusion process such as a T-die method, and can be used as the back surface side filler sheet 3. The Moreover, you may laminate | stack by extruding directly on a back sheet by the melt filler extrusion method mentioned later.

  As shown in FIG. 1, in the present embodiment, an embossed surface 31 on which uneven embossing is performed exists on the surface 3 a opposite to the laminated surface side surface 3 b side of the back surface side filler 3. . For this reason, it is preferable that the surface 3a of the back surface side filler 3 used for manufacture of the back surface integrated sheet 1 for solar cell modules is provided with an embossed surface 31 in advance or after lamination. In providing the embossed surface 31 on the front surface 3a of the back surface side filler sheet 3, a known method can be used without particular limitation. In addition, you may form the embossing surface 31 in the surface 1a after preparation of the back surface integrated sheet 1 for solar cell modules.

  The embossed surface 31 is provided on the surface 1a of the back surface integrated sheet 1 for the solar cell module of the present embodiment, so that, for example, the back surface integrated sheet 1 for the solar cell module is wound and stored. When stacked and stored, the occurrence of a blocking phenomenon in which adjacent back surface integrated sheets for solar cell modules stick to each other can be suppressed. Further, the layer on which the solar cell element 11 is provided has a part where the element exists and a part where it does not exist, or there is a ribbon wire (not shown) for electrically coupling the element and the element, It has space in some places. When assembling the solar cell module 10, the back surface side filler material sheet 3 becomes a member in contact with the solar cell element 11, but the embossed surface 31 is on the surface 1 a on the back surface side filler material sheet 3 side in contact with the solar cell element 11. By providing, the air of the space which exists in the layer of the solar cell element 11 can be discharged | emitted efficiently in the case of the vacuum lamination process in the assembly of the solar cell module 10. FIG. From the above viewpoint, the surface roughness Ra of the laminated embossed surface 31 after integration is preferably 2.0 to 13.0 μm, and more preferably 2.0 to 10.0 μm.

<Lamination process>
The manufacturing method of the back surface integrated sheet of this embodiment is a method for manufacturing the back surface integrated sheet 1 already described. The laminating method is not particularly limited, and is a dry laminating method in which bonding is performed through an adhesive. The thermal lamination method of softening or melting the side facing the back sheet by heating from the back sheet side simultaneously with pressurizing the back sheet and the back side filler sheet in these thickness directions, on the back sheet, Examples thereof include a melt filler extrusion method in which a resin composition constituting the filler is melt extruded.

  Among these, from the viewpoint of warpage reduction, a dry laminating method and a molten filler extrusion method that can reduce the internal stress of the back surface side filler during lamination are preferable, and a molten filler extrusion method is particularly preferable.

  And in this invention, it is characterized by making a laminated body which passed through this lamination process into a winding body by winding up so that a back surface side filler may become an outer side, and storing for a fixed period in the state of the said winding body .

  FIG. 3 is an example in the dry laminating method or the thermal lamination method, and the back sheet 2 is fed out from one winding body on the upper right side of FIG. 3, and the sheet-like shape is taken from the other winding body on the lower right side in FIG. The back surface side filler 2 is fed out, and both sheets are laminated by the nip roll 20 to form the back surface integrated sheet 1, which is wound up again to obtain the wound body 15. At this time, the winding direction of the winding body 15 is wound so that the arrow direction, that is, the back side filler is on the outside.

  That is, in the back surface integrated sheet, warpage occurs due to shrinkage of the back surface side filler, so that the warpage direction is the back surface side filler on the inner peripheral surface side of the warp, and the back surface sheet is the outer peripheral surface side of the warp. For this reason, it becomes possible to reduce a curvature by giving the winding habit of the opposite direction at the time of winding. At this time, in order to make the tension uniform in the winding length direction during winding, it is preferable to wind up with a constant torque as a taper tension according to the winding diameter.

  Moreover, said winding habit can be effectively imparted by holding the wound body for a predetermined period in order to impart the winding habit. Preferred storage conditions are at 30-50 ° C. for at least 24 hours. In addition, since aging in the dry laminating method satisfies the above storage conditions, this can be used as a storage process. That is, in the dry laminating method, there is substantially no storage step.

<Solar cell module>
Next, an example of the solar cell module 10 in which the back integrated sheet 1 according to an embodiment of the present invention is used will be described with reference to FIG.

  As shown in FIG. 2, the solar cell module 10 is laminated in order of the back surface integrated sheet 1, the solar cell element 11, the front surface side filler sheet 12, and the transparent front substrate 13 from the back surface 10 b side of the solar cell module 10. Composed. In addition, the back surface integrated sheet 1 is laminated | stacked so that the side 1b of the back sheet 2 may correspond with the back surface 10b of a solar cell module. For this reason, the back surface side filler sheet 3 included in the back surface integrated sheet 1 is provided in contact with the solar cell element 11. Moreover, the surface side filler sheet 12 in the solar cell module 10 is not particularly limited, but the same material as the back side filler sheet 3 already described can be used.

  For example, the solar cell module 10 is formed by sequentially laminating the members forming each of the above layers and then integrating them by vacuum suction or the like, and then thermocompression-bonding each of the above layers as an integrally formed body by a molding method such as a lamination method. Can be manufactured.

  As mentioned above, although the manufacturing method of the back surface integrated sheet for solar cell modules of this invention was shown concretely showing embodiment and embodiment, this invention is not limited to the said embodiment and embodiment. The present invention can be implemented with appropriate modifications within the scope of the configuration of the present invention.

  Hereinafter, the present invention will be described in more detail with reference to examples.

<Backside filler>
Filler composition A (polyethylene-based A) and filler sheet A:
A linear low density polyethylene having a density of 0.901 g / cm ³ and a melt mass flow rate at 190 ° C. of 2 g / 10 min was used as a base resin, and this base resin was used as a master batch A1.
100 parts by mass of a linear low density polyethylene resin having a density of 0.901 g / cm ³ and a melt mass flow rate at 190 ° C. of 1 g / 10 min, 3 parts by mass of vinylmethoxysilane, and t as a radical generator -0.1 part by weight of butyl-peroxyisobutyrate was mixed, melted and kneaded at 200 ° C to obtain a silane-modified resin. This silane-modified resin was designated as master batch A2.
Next, 4.6 parts by mass of a hindered amine-based light stabilizer, 3.4 parts by mass of a benzophenone-based UV absorber, phosphorus, 91.5 parts by mass of a linear low-density polyethylene resin having a density of 0.924 g / cm ³ 0.5 part by mass of the system heat stabilizer was mixed, melted and processed to obtain a master batch A3.
The filler composition A was obtained by adding 20 parts by mass of the master batch A2 and 5 parts by mass of the master batch A3 to 80 parts by mass of the master batch A1. By using this filler composition A as a sheet using a φ150 mm extruder and a film forming machine having a 1000 mm wide T-die, a filler sheet A having a total thickness of 400 μm was produced.

Filler composition B (polyethylene B) and filler sheet B:
A1 linear low-density polyethylene is a copolymer of ethylene and 1-hexene, and has a density of 0.880 g / cm ³ and a melt mass flow rate (MFR) at 190 ° C. of 3.4 g / 10 min. A filler composition B and a filler sheet B were obtained under the same conditions as the filler composition A except that the metallocene-based linear low-density polyethylene was used.

Filler composition C (EVA-based) and filler sheet C:
Ethylene-vinyl acetate copolymer resin (EVA; melt mass flow rate 2 g / 10 min, vinyl acetate pigment 25% by mass) was used as the base resin.
With respect to 100 parts by mass of this base resin, 1.5 parts by mass of a crosslinking agent (2,5-dimethylhexane, 2,5-dihydroperoxide), 0.2% of a silane coupling agent (γ-chloropropyltrimethoxysilane) Part by mass and 2.0 parts by mass of a crosslinking aid (triallyl isocyanurate) were added to obtain a filler composition C. By making this filler composition C into a sheet using a φ150 mm extruder and a film molding machine having a 1000 mm wide T-die, a filler sheet C having a total thickness of 400 μm was produced.

<Back sheet>
White PET 50 μm (trade name: Lumirror) and aluminum foil 20 μm were bonded together by a dry laminating method through a urethane adhesive to obtain a back sheet.

The filler or filler sheet of (A) to (C) above is laminated with the corona-treated backsheet aluminum foil surface by the laminating method of (a) to (c) below so that the backside filler is on the outside. A wound body having a width of 1000 mm × 500 m was obtained with a constant torque. This was subjected to storage treatment at 40 ° C. for 72 hours except for (a), and the back integrated sheets of the examples were obtained. For (a), the aging process was a storage process.
(A) Dry lamination: The above filler sheet and back sheet were laminated via a urethane adhesive, and then subjected to an aging treatment at 45 ° C. for 72 hours.
(B) Extrusion of molten filler: The resin composition having the composition shown in Table 1 was laminated by extruding 400 μm on a corona-treated back sheet using a film forming machine having a T die.
(C) Thermal lamination: Each of the above-mentioned filler sheet and back sheet was laminated by thermal lamination under the condition of 120 ° C. dielectric roll heating.

  Comparative example: A winding body of a comparative example was obtained under the same conditions as in the example except that the winding direction was reversed so that the back surface filler was inside.

  Evaluation Example: The warpage amount was measured by the following method for the back surface integrated sheets of the above Examples and Comparative Examples. The results are summarized in Table 1.

<Measurement method of warpage>
As shown in FIG. 4, when a test piece of A4 size is cut out from the back surface integrated sheet so that MD (flow direction) is A4 long side (297 mm) and spread on a horizontal plate with the filler side facing upward Y ₁ (mm) was measured with a scale for the height of the filler side warpage at the end of the long side (see FIG. 4A). Incidentally, was overlapped and displayed if warpage to curl more Y ₂ are overlapped as shown in vigorous FIG 4 (b). The results are shown in Table 1.

  As is apparent from Table 1, the amount of warpage can be suppressed by making the winding direction of the winding body the outer side filler. As the lamination method, a dry lamination method and a melt filler extrusion method are preferable, and a melt filler extrusion method is most preferable. It can also be seen that the lower density olefin B and EVA are preferred as the filler.

DESCRIPTION OF SYMBOLS 1 Back integrated sheet 2 Back sheet 3 Back surface side filler 10 Solar cell module 11 Solar cell element 12 Surface side filler 13 Transparent front substrate 15 Winding body

Claims (5)

A back sheet used for the back surface side of the solar cell module, and a back surface side filler, a method for producing a back surface integrated sheet for solar cell modules, comprising:
A laminated body that has undergone a laminating process is wound up so that the filler is on the outside, and is taken up as a wound body, and is stored in a state of the wound body for a certain period of time. Production method.   The manufacturing method of the back surface integrated sheet for solar cell modules of Claim 1 with which the storage in the state of the said winding body is performed at 30-50 degreeC for at least 24 hours or more.   The manufacturing method of the back surface integrated sheet for solar cell modules of Claim 1 or 2 with which the said filler mainly contains the ethylene-vinyl acetate copolymer whose vinyl acetate content is 15-45 mass%. The manufacturing method of the back surface integrated sheet for solar cell modules of Claim 1 or 2 with which the said filler mainly contains the metallocene linear low density polyethylene which is the range of density 0.870-0.890g / cm < ³ >.   The manufacturing method of the back surface integrated sheet for solar cell modules of any one of Claim 1 to 4 whose said lamination process is a process of melt-extruding the resin composition which comprises a filler on a backsheet.

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