JPS60201652A - Back surface protective sheet for solar cell module - Google Patents

Abstract

PURPOSE:To contrive to shorten the process, to form a filler sheet in a thin film at solar cell module manufacturing work by a method wherein a heat-resistant resin film evaporated to both of the surfaces thereof with vitreous moistureproof films mainly consisting of silicon oxide to be substituted for metal foil as vapor barriers is provided. CONSTITUTION:A back surface protective sheet for solar cell module is constructed of a heat-resistant and weather-resistant resin film 3, a heat-resistant resin film 5 evaporated to both the surfaces thereof with glass type moistureproof films 4, 4', and an adhesive resin layer 6. The heat-resistant and weather-resistant resin film 3 is laminated on the outside surface of the glass type moistureproof film 4', and checks generation of pin holes in the glass type moistureproof film 4' according to mechanical pressure, an impact, etc. to be applied from the outside. The heat-resistant resin film 5 checks deterioration of parts such as a solar cell element and inside wirings, etc. to be caused by invasion of moisture to the inside from the outside of a solar cell module. The adhesive resin layer 6 is arranged on the innermost surface of the protective sheet, and protects parts such as a solar cell element, inside wirings, inside of the solar cell module from a mechanical shock and pressure to be applied from the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a laminated material used as a back protection sheet for a solar cell module.

(Constitution of conventional technology and its problems) The basic function of a solar cell module is to efficiently guide the sun's radiant energy to the solar cell element, and to ensure that the solar cell element and internal wiring can withstand harsh natural environments for a long period of time. The purpose is to protect. Conventionally, solar cell modules generally have an upper transparent material (9) that serves as a structural support for the entire module, as shown in Figure 1. For example, an upper transparent material (91) such as a glass plate and a coated steel plate or M foil Solar cell elements (71) made of monocrystalline silicon, etc., which are interconnected, are inserted between the back protection sheets such as fluorinated vinyl sheets sandwiched with For insulation, the space between the upper transparent material and the lower substrate material is filled with a filler (81) such as silicone resin, and the whole is filled with aluminum,
It is enclosed and fixed using a frame (101) made of stainless steel or the like.

Furthermore, in recent years, there has been a strong push for early commercialization of solar power generation as an alternative to conventional petroleum-based energy, and the filler (8) used in modules has changed from liquid silicone resin to sheet-like butyral resin, and even more. has been replaced by lower-cost ethylene-vinyl acetate copolymer resin sheets, and module composite methods are rapidly progressing toward only heat pressing.

Here, back protection sheet) (ill) protects the internal components of the solar cell module (solar cell elements, internal wiring, etc.) from external forces such as mechanical shock and pressure from the outside, and protects them from external forces such as moisture intrusion from the outside. It is an important material provided as a moisture-proof membrane to prevent the internal parts of the module from deteriorating.

Conventionally, a laminated material having a structure as shown in a cross-sectional view in FIG. 2 has been used as a back protection sheet. That is, the moisture-proof metal foil (2) is combined with the weather-resistant resin film (1).
It is a configuration in which it is sandwiched from both sides.

The weather-resistant resin film (1) is a white polyvinyl fluoride resin film that will not deteriorate due to sunlight or rain under outdoor exposure conditions when actually used as a solar cell, and a moisture-proof metal foil. As (2), for example, aluminum foil or galvanized iron foil is used.

However, when using a back protection sheet with such a structure, the mechanical strength of the white polyvinyl fluoride film is low, and the 140-15C1
During heat pressing, the protrusions on the soldered parts of the solar cell element electrodes penetrate the filler layer, and the white polyvinyl fluoride film on the inner surface that constitutes the back protection sheet is softened by the heat of ℃. There was a problem in that the solar cell element and the metal foil would be short-circuited by penetrating the metal foil (2)K in the back protection sheet and adversely affecting the battery performance.

In addition, because the filler sheet and the back protection sheet are currently separate, there are restrictions on the press pressure, temperature, and time, such as the inability to increase the press pressure due to the use of elements that are easily damaged during composite molding. The continuity and automation of the battery module manufacturing process was not achieved, the work was complicated, and there were also problems in terms of workability.

(Object of the Invention) The present invention solves the above-mentioned problems of the prior art, and provides a heat-resistant resin with a glass-like moisture-proof film mainly composed of silicon oxide deposited on both sides of the film as a moisture-proof layer in place of metal foil. By providing the film, it is possible to avoid electrical short circuits between the protrusions on the soldering part of the solar cell element electrode and the back protection sheet, and also to prevent the layer of adhesive resin that has good adhesion to the glass material. By providing it on the innermost surface as a protective layer for the glassy moisture-proof film and as a filler, which was previously separated, costs can be greatly reduced in the manufacturing process of solar cell modules, making the filler sheet thinner, etc. It is intended for down.

In addition, as a back protection sheet for solar cell modules that has a heat-resistant resin film deposited with a glass-like moisture-proof film as a moisture-proof layer instead of metal foil, a heat-resistant resin film with a glass-like moisture-proof film deposited on one side is used. Go back,
According to Japanese Patent Application No. 59-20510 filed by the present applicant, in the back protection sheet for solar cell modules of the present invention, the moisture-proof function is further enhanced by using a heat-resistant resin film with a glass-like moisture-proof film deposited on both sides. In addition, even if the glass-like moisture-proof coating on the inner surface penetrates the filler layer and pinholes occur due to contact with protrusions in the soldering of solar cell element electrode parts, the glass-like moisture-proof coating on the outer surface also remains. By providing the film, it is possible to sufficiently maintain the moisture-proof function.

(Summary of the Invention) That is, the present invention provides a heat-resistant and weather-resistant resin film that does not melt or soften at temperatures below 150°C.
The two companies provide a back protection sheet for solar cell modules that is made of a laminate of heat-resistant films with electrically insulating glass-like coatings deposited on both sides. Since there is no need to include a moisture-proof material, there is no electrical short circuit between the internal parts of the solar cell module (solar cell elements, internal wiring, etc.) and the back protection sheet, and this also reduces pressing pressure, time, temperature, etc. You can choose freely and improve the efficiency of heat press work.
In addition, since there is no risk of short circuit, the thickness of the filler sheet can be minimized, which saves on materials.
Furthermore, because the back protection sheet can be easily fused with the filler, or because the back protection sheet itself has an integrated layer of adhesive resin that functions as a filler,
What conventionally required a multi-step pressing process of backing material - filler, then filler - element can now be made into a module with only one pressing process.

(Detailed description of the invention) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 6 is a sectional view showing an embodiment of the back protection sheet for solar cell modules of the present invention, in which a heat-resistant/weather-resistant resin film (3) and a glass-like moisture-proof film 141f41' are vapor-deposited on both sides. It is composed of an adhesive resin film (5) and an adhesive resin layer (6).

The heat-resistant/weather-resistant resin film (3) is laminated on the outer surface of the glassy moisture-proof coating (4) to prevent pinholes from occurring in the glassy moisture-proof coating (4) due to external mechanical pressure, impact, etc. It is provided to prevent heat press work as a back protection sheet, and to prevent melting or deterioration due to the heat applied during the heat press process during solar cell module manufacturing. A resin film is used that does not deteriorate due to sunlight, rain, etc. even under outdoor exposure conditions when actually used as a plastic film. In particular, since heat press conditions typically involve applying heat of about 150°C, the resin film must not melt and soften at temperatures below 150°C. For example, perfluoroalkoxy resin, tetrafluoroethylene-hexafluoropropylene copolymer, halffluoroethylene 7-barfluoropropylene-
Perfluorovinyl ether terpolymer, ethylene-
In addition to fluororesin films selected from tetrafluoroethylene copolymer, chloride-hexafluoroethylene resin, polyvinylidene fluoride, and polyvinyl fluoride, polycarbonate, poly(11-methyl methacrylate), polyacrylate, or ultraviolet absorbers (such as benzophenone and There is a type of film selected from polyethylene terephthalate impregnated or kneaded with benzotriazole, etc.), or a composite film of these, and these films may be kneaded with extender pigments such as titanium oxide, and at least one side of It is acceptable even if the paper is printed solidly or with a pattern printed on it. The thickness thereof is not particularly limited as long as it can ensure the protective effect of the glassy moisture-proof film, but a film having a thickness of 12 μm or more is usually used.

A heat-resistant resin film with an electrically insulating glassy moisture-proof film f4H41' deposited on both sides (51 is a heat-resistant resin film that prevents moisture from entering the solar cell module from outside and deteriorating parts such as solar cell elements and internal wiring. The glassy moisture-proof film f4H41' is suitable for vapor deposition,
Considering continuous film formation, moisture resistance, and cost,
An inorganic film containing silicon oxide as a main component is suitable. In the case of silicon oxide, the chemical composition is usually S! Although α,
The vapor deposited film has a composition close to SiO. The thickness of the vapor-deposited film needs to be at least 2ooA or more in terms of moisture resistance, but if it exceeds 1000X, cranks are likely to occur in the film, which will actually impair the moisture resistance.
00A is preferred. In addition, the heat-resistant resin film (51) used for vapor deposition must have heat resistance so that it will not melt during the heat press during module manufacture and lose its supporting function for the vapor-deposited film, but there are no particular restrictions in terms of suitability for vapor deposition. Perfluoroalkoxy resin, tetrafluoroethylene-hexafluoropropylene copolymer, barfluoroethylene-perfluoropropylene-perfluorovinylether terpolymer, ethylene-tetrafluoroethylene copolymer, chloride-trifluoride copolymer In addition to fluororesin films selected from ethylene resin, polyvinylidene fluoride, and polyvinyl fluoride, polycarbonate, poly(1) methyl methac-11 rate, and polyac-1
), polyethylene terephthalate, poly(11amide), polyvinyl chloride, cellophane, and the like. The thickness of the heat-resistant resin film is not particularly limited as long as it is thick enough to support the vapor-deposited film, but a film having a thickness of 12 μm or more is usually used.

In the present invention, since the glassy moisture-proof film is deposited on both sides of the heat-resistant resin film, the moisture-proof property is improved compared to the case where the glassy moisture-proof film is deposited on only one side, and the glassy moisture-proof film on the inner surface is (4) Even if pinholes occur due to contact with protrusions during soldering of solar cell module element electrode parts during heat pressing for module composite, the glass-like moisture-proof coating on the outer surface (4) By providing this, moisture resistance is sufficiently maintained. Furthermore, the glassy moisture-proof coating (4)' on the inner surface also has the advantage of having good adhesion to fillers.

If an adhesive resin layer is not provided on the inner surface of the protective sheet, the innermost surface will have a glassy moisture-proof coating14)', but the fillers currently commonly used are: It is a metal oxide conductive film such as , or silicon itself, and has thermal adhesiveness with the glass plate that is the upper transparent material, and of course has a glass-like moisture-proof film (
4) It can also be easily adhered to and composited with ''. However, in order to maintain a high degree of moisture resistance, it is preferable that the surface of the glassy moisture-proof coating, which is prone to cracking, be protected until the time of heat pressing. By laminating the adhesive resin layer (6) having the function as a protective sheet, it is possible to stabilize the performance as a protective sheet and to simplify the module composite process.

The adhesive resin layer (6) is placed on the innermost surface of the protective sheet to act as a cushioning material that protects components such as the solar cell elements and internal wiring inside the solar cell module from external mechanical shock and pressure. It has the same function as the filler, which was conventionally separated from the back protection sheet, and has adhesive properties to glass and metal on the surface of solar cell elements, preferably at temperatures below 150°C. Modified resins of ethylene-vinyl acetate copolymers such as ruglycidyl methacrylate terpolymer, ethylene-vinyl acetate partially saponified product-organic acid graft quaternary copolymer, or maleic anhydride kraft polyethylene at a temperature of 120°C or less Polyester-modified resins such as carboxyl group-containing polyolefins, ethylene terephthalate)-modified alkylene ether terephthalate broth copolymers, etc. are used, and the thickness of the resin is the same as that of the back cushioning material of the solar cell module. 5 things to effectively demonstrate the effect
It is preferable that it is 0B or more.

Heat-resistant/weather-resistant resin film 1]), a heat-resistant resin film with a glass-like moisture-proof film F41 F41' deposited on both sides (51 is a dry lamination method, heat press method, etc. using an adhesive or an adhesive resin film) It can be laminated by a method, but an adhesive or adhesive film with heat resistance and weather resistance of 150°C or higher is used.Also, poly-11 vinyl butyral, ethylene-vinyl acetate copolymer and its modified resin, etc. When laminating the adhesive resin layer (6) on the glassy moisture-proof coating (4)', the adhesive resin is thermally melted and the glassy moisture-proof coating (
4) The protective sheet of the present invention can be produced using known lamination techniques, such as direct extrusion coating onto the protective sheet.

When the protective sheet of the present invention is applied to a solar cell module, the solar cell element (7), which has been wired in advance, is placed on top of the glass plate, which is the upper transparent material (9), on which the upper protective filler sheet (8) is spread. Then cover the lower protective filler layer (+8)' on top of it, or apply the back protective sheet of the present invention to the glassy moisture-proof film (4)' side or the adhesive resin layer (6) side without using it. is placed on the inner surface, and the whole is pressed at 1400° C. to 150° C. while reducing the pressure to a vacuum to fuse and integrate, and the end portions are enclosed and fixed with a frame 00) made of aluminum or the like.

As described in detail above, the back protection sheet for solar cell modules of the present invention has outstanding advantages over conventional protection sheets, especially in terms of module composite suitability. At times, short circuits between the element electrodes and the protective sheet are completely eliminated, which not only improves yield but also reduces press pressure and
Work efficiency can be improved because time, temperature, etc. can be selected more freely.

■Since there is no risk of short circuit, it is possible to minimize the thickness of the filler sheet and save on materials. ■Because a part of the back protection sheet can become a filler or can be easily fused with the filler, the conventional method required multi-step pressing under different conditions such as the back material-filler method and the filler-element method. It is possible to create a module with a single pressing process, and damage to elements is greatly reduced.Also, in terms of moisture-proofing function, the glass-like moisture-proof coating is double-layered. It has the advantage of being able to maintain a high level of moisture-proofing function even after severe mechanical pressure and impact are applied, such as during the pressing process when combining modules.

As described in detail above, the present invention provides advantages such as stabilizing the quality of solar cell modules, stabilizing manufacturing, and making it possible to save materials, and has great value in industrial fields related to solar power generation. It is something.

(Explanation of Examples) Examples of the present invention will be described below.

As a back protection sheet for a solar cell module of the present invention,
Two types of laminated materials having the following configurations were created.

Invention 1> Ultraviolet absorber kneaded polyester film (trade name Nilmirror Q-17 [manufactured by Toshi ■] thickness 25μ) / double-sided silicon oxide vapor-deposited polyester film ([manufactured by Oike Kogyo] thickness 1)
2μ) Present invention 2> Polycarbonate film (trade name: Panlite [manufactured by Teijin ■] thickness 50μ) / double-sided silicon oxide vapor deposition polyamide film ([manufactured by Oike Kogyo] thickness 15μ) / ethylene-vinyl acetate co Polymer resin layer (vinyl acetate content 36% by weight)
, thickness 400μ) of the above two types of laminated materials of the present invention and the conventional laminated materials, white polyvinyl fluoride film (trade name: Tedlar [manufactured by DuPont] thickness 68μ) /
A solar cell module with a structure similar to that shown in Figure 1 was constructed using a laminated material consisting of aluminum foil (thickness 20μ)/white polyfluorinated vinyl film (product name: Tedlar, thickness 38μ) as a back protection sheet. □ Manufactured mul.

However, when using the laminated materials of Invention 1 and the conventional example as a back protection sheet, the same sheet as the ethylene-vinyl acetate copolymer resin layer used as the adhesive resin layer in the laminated material of Invention 2 is used. A solar cell module was manufactured using this as a filler. In addition, the heat press conditions are 15
0°G −s Kq/crl −1o min.

The moisture permeability of these five types of back protection sheets for solar cell modules and the soldering of the solar cell element electrodes when 100 of each of the six types of back protection sheets were manufactured using Moseal composite solar cell modules were as follows: The following table shows the results of a comparison of the incidence of battery performance failures due to electrical shorts between the protrusions on the parts and the back protective sheet, and the workability of manufacturing operations.

As described above, by using the back protection sheet for solar cell modules of the present invention, a high degree of moisture-proofing function was obtained, and it was also effective in stabilizing battery quality and simplifying module manufacturing work. .

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of a solar cell module to which the conventional back protection sheet and the present invention are applied, FIG. 2 is a schematic cross-sectional view showing a conventional solar cell module back protection sheet, and FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows one Example of the back surface protection sheet for solar cell modules of this invention. (1) Weather-resistant resin film (2) Moisture-proof metal foil (3) Heat-resistant/weather-resistant resin film + 41 f41' Electrically insulating glassy moisture-proof film (51 Heat-resistant resin film (6) Adhesive resin layer (71 Sun) Battery element (8) Filler (9) Upper transparent material fi11 frame ■ Back protection sheet Patent application Hitotoppan Printing Co., Ltd. Representative Kazuo Suzuki No. 11"<1 Figure 2 Figure 3

Claims (1)

[Claims] Heat resistance that does not melt and soften at temperatures below 131150°C;
A back protection sheet for a solar cell module comprising a laminate in which a heat-resistant film having at least an electrically insulating glassy moisture-proof film deposited on both sides is laminated on the inner surface of a weather-resistant resin film. (2) A back protection sheet for a solar cell module according to claim 11, wherein the electrically insulating glassy moisture-proof coating is characterized by silicon oxide. (3) Adhesive to the inner surface of the electrically insulating glassy moisture-proofing coating. Claim (1) or (21) comprising a resin layer
A back protection sheet for solar cell modules as described in . (4) The solar cell module according to claim (3), wherein the adhesive resin layer is a resin layer that has adhesion to glass and metal and melts and softens at a temperature below 150°C, preferably below 120°C. Back protection sheet.