JPS6240783A - Back protection sheet for solar cell module - Google Patents

Abstract

PURPOSE:To form a back protection sheet in which a burr or a bridge of a solder is penetrated by laminating a high moisture resistant film on the inner surface of a weather resistance resin film, further laminating a thermal bondable resin layer on the inner surface to reduce the thickness of the resin, and thereby preventing moisture from penetrating from the end. CONSTITUTION:A heat resistant and weather resistant film 41, a high moisture resistant film 42 and a bondable resin layer 43 are provided. The film 41 is formed to provide a hot press operability as a back protective sheet to be necessary as a resin film which is not melted nor softened at 150 deg.C or lower. The layer 43 has itself a bondability to a glass or metal of the surface of a solar cell and further a bondability to a glass substrate, and is preferably made of a resin which is melted and softened at 120 deg.C or lower. The intermediate layer 42 is required for high moisture resistance and no penetration in case of contacting with a burr or a bridge of a solder.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a back protection sheet for solar cell modules.
In particular, it relates to a back protection sheet for a simple solar cell module.

[Conventional technology]

Due to the demand for low cost and mass production of solar cell modules, amorphous silicon semiconductors,
Recently, a large number of simple solar cell modules using rho-group compound semiconductors and the like have been manufactured.

To explain this, a conceptual diagram is shown in Fig. 2, in which an element (2) is formed by vapor deposition or printing on a transparent substrate such as a transparent plastic plate or glass plate, and a metal wire or metal foil 13) is formed on a transparent substrate such as a transparent plastic plate or glass plate. After soldering the back side protective sheet (4), the terminal is attached to the element (1) which is closely attached to the board (1).
2) The end portion I211 of the layer and metal, foil or metal foil (3). At this time, the role of the back protection sheet (4) is to protect the element (2) and the wiring 111I made of metal wire or metal foil.
Therefore, it is required to have excellent weather resistance, moisture permeation resistance, adhesion to the substrate 11), and physical strength.

As the back protection sheet (4), a laminate of "polyvinyl sulfide/aluminum foil/polyvinyl fluoride/adhesive resin" has been known from the viewpoint of weather resistance, moisture permeability, adhesion to the substrate, etc. However, as mentioned above, the metal wire or metal foil (3) is soldered to the element (2), so the barbs of this solder, called bridges, pierce the back protective sheet.

In order to prevent contact with the aluminum foil of the back protection sheet, the thickness of the adhesive resin cannot be made sufficiently thin. Also, a back protection sheet that does not contain aluminum foil is being considered, but the solder pads or bridges are made of poly7
If vinyl chloride film is damaged, its weather resistance will deteriorate and it will no longer be able to withstand heating and cooling over a long period of time, for example, 1,000 years. Therefore, in either case, the thickness of the adhesive resin cannot be made sufficiently thin, and it is at most 50 μm, and in practical terms, the thickness is 100 μm? I need.

However, adhesive resin is essentially a substrate (1).

It is sufficient to have a good adhesive on the element (2), metal layer or metal foil (3), and it is not only uneconomical to increase the thickness as described above, but also the moisture permeability of this adhesive resin is low. Because of their large size, they tend to allow moisture to permeate through their edges, which has the disadvantage of reducing the power generation efficiency of solar cells.

[Purpose of the invention]

Accordingly, an object of the present invention is to provide a back protection sheet that prevents moisture permeation from the edges by reducing the thickness of the adhesive resin, and that does not cause puncture caused by solder flakes or bridges.

[Summary of the invention]

To achieve this objective, the present invention provides a back surface for a solar cell module, characterized in that a highly moisture-proof film is coated on the inner surface of a weather-resistant resin film, and a heat-adhesive resin layer is further laminated on the inner surface. Provide a catch sheet.

[Detailed description of the invention]

The present invention will be described in detail below with reference to one drawing. FIG. 1 is a cross-sectional view showing one embodiment of the back protection sheet for solar cell modules of the present invention, and shows a heat-resistant and weather-resistant film T4.
11. Highly moisture-proof film, 4z, adhesive resin layer (43
).

Heat-resistant/weather-resistant resin film (4υ is provided as a back protection sheet to provide heat press workability, and does not melt or deteriorate due to the heat applied during the heat press process during solar cell module manufacturing. In addition, a resin film is used that does not deteriorate due to sunlight, rain, etc. even under outdoor exposure conditions when actually used as a solar cell.In particular, heat press conditions usually apply heat of about 150C, so 150C The resin film must not melt and soften at the following temperatures.For example, perfluoroalkoxy resin, tetrafluoroethylene-hexafluoropylene copolymer, perfluoroethylene-perfluoropropylene-berfluorovinyl ether tri-E copolymer In addition to a fluororesin film selected from ethylene-47 modified ethylene copolymer, chloride-trifluoride ethyl V resin, polyvinylidene fluoride, and polyvinyl fluoride, polycarbonate, polymethyl methacrylate, polyacrylate, or ultraviolet absorber. There is a type of film selected from polyethylene terephthalate impregnated or kneaded with (for example, benzophenone, benzotriazole, etc.) or a composite film thereof.

Next, the adhesive resin layer (43) provided as the innermost layer of the back cover sheet will be explained. Furthermore, it has adhesive properties to glass substrates and has 15
It is made of a resin that melts and softens at a temperature of less than 0.00C, preferably 120C or less.

Specifically, ethyne-vinyl acetate copolymers such as polyvinyl butyral, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-glycidyl methacrylate terpolymer, ethyne-vinyl acetate partially saponified product-existing organic acid graft quaternary copolymer, etc. Modified polymer resins or carboxyl group-containing polyone fins such as maleic anhydride grafted polyethylene.

A resin made of any one of polyester modified resins such as ethylene terephthalate-modified alkylene ether terephthalate block copolymer is used, and its thickness is 3.
It is 0μ or less. The transparency of maleic anhydride kraft polyethylene is approximately 1 oy/, 2.
The modified resin of ethylene-vinyl acetate copolymer known as Dumilan (Shikinichi Yakuhin) is hygroscopic and has a very high moisture permeability.

In view of the spirit of the present invention, this adhesive resin layer (4) is preferably formed as thin as possible, for example, 30 μm or less.

Next, the middle layer of the back protection sheet (highly moisture-proof film) 14
Let's explain about z.

This intermediate layer 142+ is required not only to have high moisture resistance but also to not break through when hit by solder or a screw. Regarding moisture resistance, if the adhesive resin layer (43) has a lower moisture permeability, a certain effect can be expected.
Preferably, it has a moisture permeability of 5 f/i/24 hr or less.

A film that satisfies these conditions has a molecular weight of 30
00,000 or more ultra-high molecular weight polyethylene (moisture permeability 1-7f/
, j・24hr, ), glass fiber or glass powder for 30~
Polyethylene mixed with 50% by weight (moisture permeability 5-51/I.24 hrj, etc.)

In addition, the lamination method for the heat-resistant/weather-resistant resin film (41J) and the highly moisture-proof resin film (47J) is not limited to the dry lamination method using an adhesive, the heat lamination method, etc., and the adhesive resin layer (431 and As mentioned above, the lamination method may be dry lamination, heat lamination, extrusion lamination using an extruder, etc., and is not particularly limited.

<Effects of the Invention> As described above, since the protective sheet of the present invention can reduce the thickness of the adhesive resin layer, it is possible to prevent moisture permeation from the edges, and it also has good weather resistance. Since a highly moisture-proof film is placed between the adhesive resin film and the adhesive resin layer, there is no solder pricking or puncture caused by bridges, and therefore there is no deterioration in the weather resistance of the weather-resistant resin film. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the back protection sheet, and FIG. 2 is a conceptual diagram of the solar cell module. (1)...Transparent substrate (2)...Element (3
)...Metal wire or metal foil (4)...Back protection sheet t4D...Weather-resistant resin film (421...Highly moisture-proof film (43)...Adhesive resin layer

Claims (3)

[Claims] (1) A back protection sheet for a solar cell module, characterized in that a highly moisture-proof film is laminated on the inner surface of a weather-resistant resin film, and an adhesive resin layer is further laminated on the inner surface. (2) The back protection sheet for a solar cell module according to claim (1), wherein the thickness of the heat-adhesive resin layer is 30 μm or less. (3) Moisture permeability of highly moisture-proof film is 5g/m^2.24
Claim No. 1 (1) characterized in that the
) or (2), the back protective sheet for a solar cell module.