JP2009218465A - Sealing film for solar battery module, and solar battery module using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing film for solar battery module improved in long-term reliability by ensuring high insulation to be required in Europe, etc., and suppression of deterioration due to an external environment, and to provide a solar battery module using the film. <P>SOLUTION: The sealing film for solar battery module comprises at least: (i) a resin film layer constituted by including a biaxial orientation foaming film; and (ii) a layer constituted of at least one selected from a group including metal, metal oxide, an inorganic compound, and an organic compound. The biaxial orientation foaming film is constituted of a resin composition having poly-p-phenylene sulfide as a main component, and has apparent specific gravity (ρ) of 0.60-1.30. The solar battery module is constituted using the sealing film for solar battery module. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sealing film for a solar cell module and a solar cell module using the sealing film. More specifically, the present invention significantly improves durability (hydrolysis resistance, harmful gas resistance, etc.) with high voltage compatibility. It is related with the sealing film for solar cell modules excellent in long-term reliability, and the solar cell module using the same.

  In recent years, solar cells attracting attention as a next-generation energy source have rapidly spread and are being developed for residential use, industrial use, and the like. In Europe in particular, it is rapidly spreading as a domestic power source rather than for residential use, and has been put into practical use on a large scale. In Europe, where the penetration rate is increasing, the transmission voltage is high, and the insulation (partial discharge voltage) required for the sealing film for solar cell modules is as high as 1000V compared to 600V in Japan and the United States.

  On the other hand, from the viewpoint of the processability of the solar cell module sealing film and the production of the solar cell module using the same, it is required to reduce the thickness of the solar cell module sealing film and maintain flexibility. Yes. That is, when the sealing film is thick, there is a problem that the element of the solar cell is damaged because it is hard, the bonding process cannot be easily performed, and the price of the sealing film is increased.

  In addition, solar cell modules are often installed for a long period of time in areas with a lot of moisture including ponds and rivers, and in areas where toxic gas is generated, such as sewage treatment plants, livestock farms, and volcanic areas. Therefore, there is an increasing demand for resistance to hydrolysis and harmful gases.

The following are known as conventional sealing films for solar cell modules.
(1) Commercially available products in which a fluororesin sheet and / or a polyethylene terephthalate film (hereinafter may be abbreviated as a PET film) as a base material and an aluminum foil having a thickness of several tens of μm as a gas barrier layer are provided. .
(2) A laminate in which a PET film, a metal oxide deposition layer for gas barrier properties and a white PET film are laminated has also been proposed (see, for example, Patent Document 1).
(3) Moreover, in addition to the improvement of hydrolysis resistance, the sealing film consisting of a PET film and a gas barrier layer is whitened to improve the reflection efficiency and weather resistance, and further the apparent specific gravity of the PET film is 0.85 to 1. .37 has been proposed to reduce weight, reduce leakage current, and improve insulation (see, for example, Patent Document 2).
(4) For use in harsh environments such as volcanoes, hot springs, water and sewage facilities, poly-p-phenylene sulfide (hereinafter sometimes abbreviated as PPS) as a gas-resistant layer on the outermost layer of the solar cell module sealing film. Proposed to provide a biaxially oriented poly-p-phenylene sulfide film (hereinafter sometimes abbreviated as PPS film) layer on a support film for a solar cell module (for example, see Patent Document 3) or a gas barrier layer provided with a certain layer. (See, for example, Patent Document 4).
(5) It is also known to improve weight reduction, cushioning, tearing strength, and impact resistance while maintaining heat resistance and the like by using a PPS film having low specific gravity by generating bubbles in the film (for example, patents) Reference 5).
No. 2002-100808 No. 2002-26354 No. 2003-31824 2005-86104 JP-A-3-134029

However, the conventional sealing film has the following problems, and development to the sealing film application for solar cell modules has been limited.
Although the thing using aluminum foil for the gas barrier layer of (1) term is excellent in gas barrier property, there existed a problem in the insulation of the sealing film and weight reduction.
The sealing film of item (2) is superior in insulation compared to item (1), but the total thickness of 300 to 400 μm is required for 1000 V, which is required in Europe. The workability of the stop film is difficult, and the solar cell element may be damaged when the solar cell module is assembled.
The sealing film of item (3) is excellent in insulation even when the insulation voltage is 1000V, which is a European requirement, but it has a thickness of less than 300 μm. Development in fields where safety and toxic gas resistance are required are limited.
The sealing film using the PPS film of (4) and (5) is excellent in the environmental resistance, but the thickness of the sealing film is increased in order to be compatible with 1000 V, and the same as in (2) There was a problem.
Although the PPS film having a low specific gravity is proposed in the item (5), there is no description about the development of the sealing film for solar cell modules utilizing the excellent insulating property, and no development has been made.

  Therefore, in view of the above-mentioned problems of the prior art, the present invention uses a sealing film for a solar cell module, which has further improved long-term reliability, with high insulation required in Europe and the like, and deterioration due to the external environment. It is intended to provide a solar cell module.

  The present invention employs the following means in order to solve such problems.

  That is, the solar cell module sealing film of the present invention comprises at least (i) a resin film layer including a biaxially oriented foam film, and (ii) a metal, a metal oxide, an inorganic compound, and an organic compound. And an apparent specific gravity (ρ) of the biaxially oriented foamed film composed of a resin composition containing poly-p-phenylene sulfide as a main component is 0. It is a biaxially oriented foam film of 60-1.30.

  Moreover, the solar cell module of this invention is comprised using this sealing film for solar cell modules, It is characterized by the above-mentioned.

  The sealing film for solar cell module of the present invention is more excellent in long-term reliability that can withstand the high insulation voltage required particularly in Europe and can withstand harsh external environments (high temperature, high humidity, toxic gas atmosphere). It became a sealing film. It is also effective in reducing weight. Moreover, the solar cell module using the sealing film for the solar cell module of the present invention can provide a highly insulating material that is highly resistant to thermal degradation, hydrolysis degradation, and poisonous gas degradation. it can.

  The present invention has intensively studied the above problems, that is, the high insulation required in Europe and deterioration due to the external environment, and has further improved long-term reliability. When a low specific gravity PPS film having excellent hydrolyzability and chemical resistance and generating bubbles in the film was used for the sealing film, it was investigated to solve such problems all at once. In other words, high insulation, thinning of the sealing film due to the high insulation, and environmental resistance (heat resistance, hydrolysis resistance, toxic gas resistance, etc.) of the sealing film are greatly improved, and long-term reliability is further improved. It is possible to provide an excellent sealing film for solar cell modules.

  As shown in FIG. 1, the basic structure of the solar cell module sealing film of the present invention is composed of two layers of a resin film layer and a gas barrier layer, and is collectively referred to as a front sheet or a back sheet. Since the stop film is opaque, it is preferably used for the back sheet.

  Here, the resin film layer is a layer composed of a plastic film, and plays a role in electrical insulation and mechanical protection of the encapsulated solar cell element. In the present invention, in order to impart both the characteristics of severe external environment resistance and high insulating properties, the resin film layer contains poly-p-phenylene sulfide (hereinafter sometimes abbreviated as PPS) as a main component. It is necessary to be configured to include a layer of a low-specific gravity biaxially oriented PPS film (hereinafter sometimes abbreviated as a low-specific gravity PPS film) that is composed of a resin composition and has bubbles generated therein. . The resin film layer may include a plastic film other than the low specific gravity PPS film.

  Examples of the film other than the low specific gravity PPS film include unstretched and stretched films, for example, polyester films made of PET, polyethylene naphthalate, etc., such as polytetrafluoroethylene (PTFE), tetrafluoroethylene and perfluoroalkyl vinyl ether. Perfluoroalkoxy resin (PFA), tetrafluoroethylene hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether / hexafluoropropylene copolymer (EPE)), tetrafluoro Copolymer of ethylene and ethylene or propylene (ETFE), polychlorotrifluoroethylene resin (PCTFE), copolymer of ethylene and chlorotrifluoroethylene resin (EC FE), vinylidene fluoride resin (PVDF), vinyl fluoride resin (PVF), etc.), olefin, nylon, polyimide, aromatic polyamide, high specific gravity PPS film (apparent specific gravity) Can be used as an example, but a PET film, a PEN film, or a high specific gravity PPS film alone or a laminated film is particularly preferred from the balance of processability, mechanical strength, weather resistance, price, and the like. Further, these films may be provided with bubbles in the inside thereof to reduce the specific gravity.

  The basic structure of the sealing film of the present invention is shown in FIG. The thickness of the resin film layer of the solar cell module sealing film is (A), and the thickness of the low specific gravity PPS film in the resin film layer is (B). When the ratio (B / A × 100) is 10% or more, more preferably 15% or more, deterioration due to severe external environment (high temperature, high humidity, toxic gas, etc.), which is one of the objects of the present invention, is achieved. A suppression effect can be achieved, which is preferable.

  Further, the low specific gravity PPS film layer may be divided into several layers and, of course, the entire resin film layer may be a low specific gravity PPS film. The low specific gravity PPS film may be a composite film of two or more layers with a high specific gravity PPS layer. A PPS film may be used as a base film for a gas barrier layer, which will be described later. In this case, a high specific gravity PPS film (hereinafter sometimes abbreviated as a PPS film) is preferably employed.

  Next, a layer (hereinafter referred to as a gas barrier layer) composed of at least one selected from the group consisting of metals, metal oxides, inorganic compounds and organic compounds according to the present invention is a layer having a barrier property against water vapor and oxygen. Specifically, it is a layer composed of at least one selected from the group consisting of metals, metal oxides, inorganic compounds such as silica, and organic compounds, and is formed by a known method such as vapor deposition, sputtering, or coating. Is.

Gas barrier layer according to the present invention is important towards the vapor barrier, the initial value of the water vapor transmission rate measured according to the standard of JIS K7129-1992 (value before aging) is preferably 2.0g ^/ m 2 ^/ 24hr A layer that achieves the following:

  Suitable constituent compositions of such a gas barrier layer include aluminum oxide and silicon oxide. The gas barrier layer may be provided directly on the resin film layer of the present invention by the above method, or may be provided on the resin film layer via an adhesive after being once provided on another film. The latter method is used because the price is low. Although it does not specifically limit as another film in this case, Generally, PET, PEN, PPS, and a fluorine-type film are used preferably. Although the thickness of these films is not particularly limited, those having a thickness in the range of 5 to 25 μm are preferably employed from the viewpoints of workability such as vapor deposition, sputtering and coating, and economical efficiency.

  Here, the PPS of the resin composition containing poly-p-phenylene sulfide (PPS) as a main component of the present invention is preferably 90 mol% or more, more preferably 95 mol% or more of the following formula (1): The polymer which consists of a structural unit shown by these. When the PPS component is less than 90 mol%, the crystallinity, thermal transition temperature, melting point, etc. of the polymer are low, and the heat resistance, hydrolysis resistance, mechanical properties, chemical resistance, which are the characteristics of the resin composition containing PPS as the main component. It may damage the sex.

  In the PPS resin, as long as it is less than 10 mol%, preferably less than 5 mol% of the repeating unit, other units containing a copolymerizable sulfide bond may be contained. In this case, the structural unit may be either a random type or a block type copolymerization method.

In the present invention, the resin composition containing PPS as a main component refers to a composition containing 50 mass% or more of PPS. When the PPS content is less than 50% by mass, the mechanical properties, heat resistance, hydrolysis resistance, hygroscopic dimensional stability, chemical resistance, etc. of the layer made of the composition of the sealing film for solar cell module of the present invention, etc. Damage. Further, the remaining less than 50% by mass in the composition may contain additives such as polymers other than PPS, inorganic or organic fillers, lubricants, and colorants. Further, the melt viscosity of the PPS composition is easily in the range of 100 to 50000 poise, more preferably 500 to 20000 poise, at 300 ° C. shear rate of 200 sec ⁻¹ , so that the film can be easily formed.

  A biaxially oriented film made of a PPS resin composition is a film formed by melt-extruding, biaxially stretching and heat-treating a resin composition containing PPS as a main component. The thickness is preferably in the range of 5 to 300 μm from the viewpoint of characteristics. A PPS film containing an additive in the above range and colored in white, black, or the like may be used.

  The apparent specific gravity referred to in the present invention was determined by measurement according to ASTM-D1505. The apparent specific gravity of the low specific gravity PPS film of the present invention is in the range of 0.60 to 1.30, preferably 0.60. Those in the range of ˜1.20 are preferred. When the apparent specific gravity is less than 0.50, the strength of the film itself is weak, it is difficult to process the sealing film for solar cell module of the present invention, and when incorporated in the solar cell module, the film is laminated on the outermost package of the sealing film. If it is done, it will be easily destroyed by scattered sand, wind and rain. Conversely, when the apparent specific gravity exceeds 1.30, the amount of bubbles inside the film is small, and the effect of improving insulation (partial discharge voltage) is reduced.

  The term “foaming” as used in the present invention means that bubbles (voids) are present in the PPS film layer of the present invention, and the presence of the voids can be confirmed by observing the cross section of the film with an electron microscope or the like.

  In the present invention, in order to quantitatively represent the generation amount of the voids, the thickness deformation rate C% [C = α−β / calculated from the deformation amount of the film when a light load and a heavy load are respectively applied to the film. α × 100: where α is the film thickness (μm) at light load, and β is the film thickness (μm) at heavy load]. The film deformation rate is preferably 9 to 50%, more preferably 12 to 35% for the same reason as the preferred range of apparent specific gravity.

  In the present invention, a high specific gravity PPS layer may be laminated on at least one surface of the low specific gravity PPS layer, or two or more PPS layers having different apparent specific gravity as referred to in the present invention may be combined.

  The solar cell module of the present invention refers to a system that converts sunlight into electricity, and an example of the structure is shown in FIG. That is, the front sheet layer, the filling adhesive resin layer, the solar cell element, the filling adhesive resin layer, and the back sheet layer are basically configured from the side on which sunlight is incident. Some of these solar cell modules are incorporated in the roof of a house, installed in farm ponds, ranches, wastewater and sewage treatment facilities, volcanoes, hot spring areas, buildings and fences, and used in electronic parts. Some of the solar cell modules transmit light called daylighting type or see-through type and are used for soundproof walls such as windows, highways and railways. A flexible type has also been put into practical use.

  Here, the front sheet layer is a layer provided for the purpose of efficiently making sunlight incident and protecting the internal solar cell element, and a gas barrier layer is laminated on glass or a highly transparent, high light transmittance plastic, film, etc. Is generally used.

  Further, the filling adhesive resin layer is a layer for the purpose of adhesion and filling for storing and sealing the solar cell element between the front sheet and the back sheet, weather resistance, water resistance (hydrolysis resistance), Transparency, adhesiveness, etc. are required. Preferable examples include ethylene vinyl acetate copolymer resin (sometimes abbreviated as EVA), polyvinyl butyral, ethylene vinyl acetate partial oxide, silicon resin, ester resin, olefin resin, and the like. Is the most common. Further, the back sheet layer is intended to protect the solar cell element on the back side of the solar cell module, and is required to block water vapor, electrically insulate, and mechanical properties.

  The solar cell module sealing film of the present invention is generally the above-described front sheet and back sheet, but the present invention is characterized by the use of an opaque low specific gravity (in which bubbles are generated) layer. For this reason, it is preferable to use the back sheet layer for the purpose of insulation and mechanical protection rather than the front sheet on which sunlight is incident. The configuration is basically the two layers of the resin film layer and the gas barrier layer described above. The total thickness is preferably in the range of 30 to 500 μm, more preferably in the range of 35 to 300 μm, from the viewpoint of mechanical strength, electrical insulation and workability, and weight reduction.

  Moreover, the solar cell module sealing film of the present invention may be coated or laminated with a material having an ultraviolet absorption effect for the purpose of weather resistance. A circuit may be formed on the surface of the sealing film with a metal layer, a conductive resin layer, a transparent conductive layer, or the like.

  Next, an example is demonstrated about the manufacturing method of the sealing film for solar cell modules of this invention.

  First, the manufacturing method of the low specific gravity PPS film which comprises the sealing film for solar cell modules of this invention is described. PPS uses a method in which an alkali sulfide and p-dichlorobenzene are reacted in a polar solvent at high temperature and high pressure. In particular, it is preferable to react sodium sulfide and p-dichlorobenzene in an amide-based high-boiling polar solvent such as N-methyl-pyrrolidone. In this case, in order to adjust the degree of polymerization, it is particularly preferable to add a so-called polymerization aid such as a caustic alkali or an alkali metal carboxylate and react at 230 to 280 ° C. The pressure in the polymerization system and the polymerization time are appropriately determined depending on the type and amount of the auxiliary agent used and the desired degree of polymerization. Furthermore, it is preferable to wash the obtained polymer with water or an organic solvent not containing metal ions for the purpose of removing by-product salts and polymerization aids during polymerization.

External particles are added to the PPS thus obtained because air bubbles are formed in the film during the biaxial stretching process. As the external particles used in the present invention, organic polymer particles and / or inorganic particles composed of oxides, carbides, nitrides or inorganic salts of elements of Group II, III, and IV of the Periodic Table of Elements can be used. Of these, external particles satisfying the following formula are particularly preferable in relation to the addition amount of X (X mass%) and the average particle diameter (Y μφ) of the external particles.
・ 0.4 ≦ Y ≦ 2.5 (1)
・ X ≦ 40 (2)
(13-5Y) ≦ X ≦ (100-35Y) (3).

  Preferable examples of the organic polymer particles include divinylbenzene / styrene copolymer (crosslinked), polyimide, silicone resin particles and the like. Further, the temperature at the time of 10% weight loss in the heating weight loss curve is preferably 370 ° C., more preferably 390 ° C., and particularly preferably 420 ° C. or more, from the viewpoint of discharge stability at the time of melt extrusion. The upper limit of the temperature at the time of 10% weight loss is not particularly limited, but usually about 600 ° C. is the production limit.

  Examples of the inorganic particles include synthetic calcium carbide, heavy calcium carbonate, carbon black, titanium monoxide, titanium dioxide, CaF2, LiF, MgF3, wet silica, colloidal silica, dry silica, aluminum silicate, calcium silicate, sulfuric acid. Barium, aluminum oxide, aluminum hydroxide, calcium phosphate and the like are preferably used.

  In the present invention, the true density of the external particles is preferably 4.5 or less, more preferably 3.5 or less. When the density exceeds the above range, it is difficult to develop a specific gravity which is a feature of the present invention.

  Two or more kinds of the above external particles may be mixed and used.

  In terms of reducing the specific gravity, the average particle diameter Y of the external particles and the additive amount X of the external particles in the present invention satisfy the ranges of the above formulas (1), (2), and (3) at the same time. Particularly preferred. That is, if the range of the formula (1) is not satisfied, it is difficult to control the specific gravity. Further, if the ranges of the formulas (1) and (2) are not satisfied, film tearing during film formation, filter clogging during melt extrusion, and the like are likely to occur, and the productivity of the film may be reduced. If the range of the formula (3) is not satisfied, the balance between the amount of bubbles generated inside the film and the increase in the specific gravity of the film due to the added external particles cannot be controlled, and it may be difficult to control the specific gravity of the film.

  The PPS resin composition of the present invention is produced by melt-kneading by mixing PPS, external particles, and additives having various functions, if necessary, in the above suitable mixing range. First, the external particles are produced in the form of a slurry (hereinafter sometimes abbreviated as particle slurry) dispersed in a liquid having a boiling point of preferably 180 to 290 ° C., more preferably 180 to 250 ° C. with a ball mill or the like. A mixture obtained by uniformly mixing the PPS polymer with a PPS polymer using a high-speed stirrer such as a Henschel mixer is supplied to a melt extruder having at least one stage vent hole, and the liquid component is first removed from the vent hole after melt kneading in the melt extruder. It is particularly preferable to produce by extruding from a suitable die. Even when an extruder having two or more stages of vent holes is used, it is preferable that the final venting is performed in a molten state of the polymer, and some liquid components in the unmelted mixture are partially removed from some of the vent holes. Even in this case, the ratio is preferably 50% by mass or less of the liquid component. In any case, it is most preferable for the kneading of the present invention to create a state in which the liquid, external particles, and molten polymer coexist in the cylinder of the extruder.

  In this way, the liquid component in the polymer can remove adverse effects caused by vaporization of the liquid, such as foaming, as compared with the case where the finally obtained resin composition is processed by an extruder without vent holes. Preferable examples of the liquid include ethylene glycol, triethylene glycol, N-methylpyrrolidone, diphenyl ether, etc., but those that cannot melt PPS at a temperature higher than the boiling point as in the former two. Particularly preferred. In addition, the content of external particles in the slurry is preferably in the range of 10 to 70% by mass in the film forming process.

  The PPS resin composition thus obtained is adjusted so as to have a desired addition amount, vacuum-dried and then sequentially known biaxial stretching method, simultaneous biaxial stretching method using a tenter method or a tubular method, etc. To obtain a biaxially oriented film.

  The drying conditions of the PPS resin composition are usually performed at a temperature of 120 to 200 ° C. for 3 hours or longer (the degree of vacuum is 0 to 80 mmHg). The conditions for biaxial stretching vary somewhat depending on the properties of the polymer used and the stretching method, but in the case of sequential biaxial stretching, the longitudinal direction of the film (hereinafter sometimes abbreviated as MD) and the width direction (hereinafter referred to as TD). In some cases, the stretching temperature is in the range of 85 to 105 ° C., the stretch ratio is 1.5 to 4.5, and the stretch ratio of MD and TD (stretch ratio of MD / stretch ratio of TD) is 0. The range of .6 to 1.3 is preferable in terms of the uneven thickness of the film, the control of the molecular orientation, and the balance of the heat shrinkage rate. Further, the degree of orientation OF is controlled to 0.33 to 0.75 in both the Edge direction and the End direction, and the ratio of both directions (Edge direction / End direction) is preferably 0.7 to 1.4, more preferably 0.8. The range of -1.3 is particularly good in terms of prevention of environmental degradation of mechanical properties, heat resistance, and chemical resistance. Here, the degree of orientation OF measured from the Edge direction (or End direction) is an X-ray plate photograph by X-ray incidence from a direction parallel to the film surface and parallel to the width direction (or longitudinal direction). The blackening degree in the 30 ° direction (Iφ = same as the blackening degree (Iφ = 0 °) when the diffraction ring from the (200) plane of the PPS crystal is scanned radially on the equator with a microdensitometer. 30 °) is defined by the ratio Iφ = 30 / Iφ = 0 °.

  The biaxially stretched PPS film thus obtained is further subjected to a heat treatment temperature of preferably 240 ° C. to the melting point of the polymer, more preferably 250 ° C. to the melting point of the polymer, and a time of 1 to 60, under a limit shrinkage of 15% or less. Heat treatment is performed in the range of seconds, and the low specific gravity PPS film of the present invention can be obtained. Moreover, it is preferable that the surface treatment and the anchor coat process aiming at improving easy-adhesion are performed on the front and back of the film.

  As the resin film other than the low specific gravity PPS film constituting the sealing film for a solar cell module of the present invention, a PET film, a PEN film, a PPS film, a fluorine-based film, a polyimide, an aromatic polyamide film, or the like can be used. Generally, a commercially available film product can also be employed. Moreover, it is preferable that the surface treatment and the anchor coat process aiming at improving easy-adhesion are performed on the front and back of the film.

  As the resin film layer of the present invention, a low specific gravity PPS film of the present invention or a laminated film with the above-mentioned various films is used. Lamination is performed by applying a known adhesive solution such as urethane, polyester, acrylic, epoxy, etc., using a known method such as a gravure roll coater, reverse coater, die coater, etc., and heating at a temperature of 50 to 120 ° C. It can be laminated by a roll press method or the like. Further, the adhesive is cured as necessary. Of course, it is also included in the present invention to perform lamination without using an adhesive layer, such as performing surface treatment such as plasma treatment and heat fusion lamination.

  Next, the gas barrier layer according to the present invention is formed on at least one surface of a film such as a PPS film, a polyester film such as a PET film or a polyethylene naphthalate film, or a fluorine-based film, for example, aluminum oxide, silicon oxide, magnesium oxide, tin oxide, oxide A film of a simple substance or a mixture of metal oxides such as titanium can be formed by a known vacuum deposition method or sputtering method. Of course, several layers of the same or different metal oxide layers may be laminated. In this case, the thickness of the gas barrier layer is usually selected from the range of 100 to 2000 angstroms. Moreover, it is rather preferable that the surface of the film is subjected to a known surface treatment for easy adhesion before providing the gas barrier layer.

  Next, the solar cell module sealing film of the present invention is obtained by laminating a gas barrier layer on at least one surface of the resin film layer obtained above. As described above, the gas barrier layer can be provided directly on the resin film layer by vacuum deposition or sputtering with an inorganic material such as a metal oxide. In addition, a film in which a gas barrier layer is once laminated on a film layer (hereinafter referred to as a gas barrier layer support film) can also be laminated on a resin film layer. In this case, a well-known adhesive solution such as urethane, polyester, acrylic or epoxy is applied to the surface of the gas barrier layer support film layer or resin film layer by a known method such as a gravure roll coater, reverse coater or die coater. Then, the gas barrier layer supporting film layer and the resin film layer are laminated at a temperature of 50 to 120 ° C. by a method such as a heated roll press method. At this time, the gas barrier layer may be provided on either side of the gas barrier layer supporting film.

  In addition, when laminating a layer having weather resistance according to the present invention, the layer is laminated on the at least one surface of the sealing film by the above-described method via the adhesive layer used above, or weather resistance. A resin solution can be applied and laminated by a known coating method.

  Here, the thickness (B) μm of the PPS film in the resin film layer (including the resin film layer provided with the gas barrier layer) of the sealing film is the thickness (A) of the entire sealing film obtained above. ) When the lamination ratio is 10% or more with respect to μm, the environmental resistance (heat resistance, hydrolysis resistance, weather resistance, harmful gas resistance, etc.) of the solar cell module sealing film can be maintained over a long period of time. Therefore, it is preferable. That is, the effect of maintaining the environmental resistance of the sealing film for solar cell modules by the PPS film comes to appear. If the lamination ratio is less than 10%, the environmental resistance of the solar cell module sealing film may be lowered. This PPS film may be laminated in one layer or several layers separately.

  Next, the manufacturing method of the solar cell module of this invention is demonstrated.

  The solar cell module of the present invention is configured, for example, in the form shown in FIG. For example, a transparent plate glass is prepared for the front layer, the sealing film layer obtained above is prepared for the back sheet layer, and both sides of the solar cell element are filled with an adhesive resin layer such as EVA having a thickness of 100 to 1000 μm as described above. The front layer and the sealing film (preferably with the gas barrier layer facing the resin film) can be laminated. In the present invention, a sealing film having front layer side transparency, weather resistance, and hydrolysis resistance can also be used for the purpose of weight reduction. Furthermore, it is more preferable to use a resin layer surface having weather resistance on the incident side of sunlight. Moreover, the sealing film in the case of using for a back sheet may be colored white or black. Here, well-known methods can be used as the lamination method, but the vacuum lamination method is preferable because defects such as wrinkles and bubbles are less likely to occur and the layers can be uniformly laminated. The laminating temperature is usually in the range of 100 to 180 ° C. Furthermore, the lead cell which can take out electricity is provided, and it fixes with exterior material, and the solar cell module of this invention is obtained.

  The following examples illustrate the present invention in more detail. First, the evaluation method of the various characteristics of the sealing film for solar cell modules obtained by each Example and the comparative example is demonstrated.

<Physical properties and evaluation methods, evaluation criteria>
(1) the apparent specific gravity light liquid film, n- heptane (0.68 g / cm ^3), the heavy liquid, measured according to ASTM-D15005-1968 using carbon tetrachloride (1.59 g / cm ³⁾ did. As a measurement sample, a low specific gravity PPS film portion was cut out from the solar cell module sealing film, the number of measurements was 2, and the apparent specific gravity was the average value.

(2) Film deformation rate A 10 g base is attached to the top of the spindle of a Mitsubishi dial gauge (No. 2109-10, probe: 3 mmφ hard ball), and the spindle is lifted and placed on the film sample set on the measuring table. A 50 g weight is placed on the pedestal as a light load, and the thickness after 5 seconds is read. This thickness is α μm. Further, the weight of the pedestal is replaced with a heavy load of 500 g, and the thickness after 5 seconds is read. This thickness is β μm. From these numerical values, the film deformation rate C (%) was calculated by the following formula.
C = (α−β) / α × 100.

(3) Specific gravity of external particle It calculated | required by the pycnometer method using xylene or an aqueous solution of sodium hexametaphosphate (0.003 mol / L) as a solvent (average value of two measurements).

(4) Average particle diameter of external particles External particles are added to a dispersion solvent such as methanol or ethanol and dispersed by an ultrasonic dispersion method. The obtained dilute dispersion of external particles is dropped on a smooth sample stage and sufficiently dried to prepare a sample for measuring average particle diameter. Alternatively, PPS is removed from the film by a plasma low-temperature ashing method (for example, PR-503 manufactured by Yamato Kagaku), and external particles are exposed to prepare an average particle size measurement sample. The treatment conditions are selected such that PPS is ashed but external particles are not damaged. This is observed with a scanning electron microscope (SEM), and the image of the particles (light density produced by the particles) is connected to an image analyzer (for example, QTM900 manufactured by Cambridge Instrument). The treatment was performed, and the numerical average diameter D determined thereby was defined as the average particle diameter.
・ D = ΣDi / n
Here, Di is the equivalent-circle diameter of the particles, and n is the number.

(5) Lamination ratio (A / B)
The cross section of the sealing film for solar cell module was observed with a 10 to 200 times optical microscope, photographed, the dimensions of the cross section photograph were measured, and the lamination ratio (A / B × 100) was determined and displayed in% (different locations) Is represented by the average value measured three times). Here, the B layer is the total thickness of only the film layer of the sealing film layer. The number of samples for each example / comparative example is three, and the thickness at three locations per sample is measured, so the average value of a total of nine locations was taken as the lamination ratio of each example / comparative example.

(6) Insulation voltage (PDC) of solar cell sealing film
The insulation voltage was measured by applying a voltage under conditions of 23 ° C. and 65% RH using a partial discharge tester KPD2050 manufactured by Kikusui Electronics Co., Ltd.

(7) Insulation improvement effect The insulation voltage was judged according to the following criteria as compared with a conventional sealing film not using a foamed PPS film. In addition, the insulation voltage of the sealing film which does not use a foam film was measured beforehand for every thickness of the sealing film, and compared with the numerical value.
○: The insulation voltage value is more than 1.2 times that of the conventional product, which greatly improves insulation and greatly improves reliability.
Δ: Although the insulation voltage value is 1.1 times or more and less than 1.2 times that of the conventional product and the insulation is improved, the effect is small.
X: The insulation voltage value is less than 1.1 times that of the conventional product, and the effect of improving insulation is not recognized.

(8) Water vapor transmission rate The water vapor transmission rate of the sealing film was measured based on the method B of JIS K7129-1992 (the measurement condition was set to a temperature of 40 ° C and a humidity of 90% RH).

(9) Hydrolysis resistance A 10 mm wide (150 mm long) cut is made in advance so that the tensile strength can be measured in an 80 mm × 200 mm size sealing film and aged in an atmosphere of 85 ° C. × 93% RH for 2000 hours. The breaking strength before and after the aging was measured based on JIS C2151-1990, and was comparatively evaluated by the ratio (retention rate (%)) calculated by the following formula. The number of evaluations was 5 for each example and comparative example, and the average retention rate was determined according to the following criteria. If the retention rate is 40% or more (◯ or Δ), it is a pass.
・ (Breaking strength after aging) / (Breaking strength before aging) × 100
○: Retention rate of break strength is 50% or more Δ: Retention rate of break strength is 40% or more and less than 50% ×: Retention rate of break strength is less than 40%.

(10) Weather resistance Five cycles of the following cycle were carried out using an accelerated tester iSuper UW tester. The breaking strength was measured by the same method as in (9) above, and the retention rate was obtained and evaluated. The number of evaluations was 5 for each example and comparative example, and the average retention rate was determined according to the following criteria. If the retention rate is 30% or more (◯ or Δ), it is a pass. 1 cycle: UV irradiation for 8 hours in an atmosphere at a temperature of 60 ° C. and a humidity of 50% RH, followed by aging for 4 hours in a dew condensation state (temperature 35 ° C., humidity 100% RH).
○: Retention rate of break strength is 40% or more Δ: Retention rate of break strength is 30% or more and less than 40% ×: Retention rate of break strength is less than 30%.

(11) Heat resistance The sealing film was cut into a size of 10 mm × 200 mm and a set of 5 pieces was aged in a hot air oven at 150 ° C. for 1000 hours. The breaking strength was measured by the same method as in (9) above, and the retention rate was obtained and evaluated. The number of evaluations was 5 for each example and comparative example, and the average retention rate was determined according to the following criteria. If the retention rate is 50% or more (◯ or Δ), it is a pass.
○: Retention rate of breaking strength is 60% or more Δ: Retention rate of breaking strength is 50% or more and less than 60% ×: Retention rate of breaking strength is less than 50%

(12) Hazardous gas resistance The sealing film was sampled in the same manner as in the test of (11) above, and the sample was put into a 500 cc autoclave containing 10 cc of aqueous ammonia and aged at 50 ° C. for 100 hours. The breaking strength was measured by the same method as in (9) above, and the retention rate was obtained and evaluated. The number of evaluations was 5 for each example and comparative example, and the average retention rate was determined according to the following criteria. If the retention rate is 30% or more (◯ or Δ), it is a pass.
○: Retention rate of break strength is 40% or more Δ: Retention rate of break strength is 30% or more and less than 40% ×: Retention rate of break strength is less than 30%.

(13) Mechanical strength of sealing film From the repulsive force of the film when the sealing film was pressed in the thickness direction, the mechanical strength was determined according to the following criteria.
○: There is a repulsive force, and the mechanical strength for protection of the enclosed solar cell element is sufficient.
Δ: The repulsive force is slightly weak, but the encapsulated solar cell element has a mechanical strength of a possible level.
X: Mechanical strength at a level where the repulsive force is weak and it is difficult to protect the encapsulated solar cell element.

(14) Overall evaluation of sealing film (overall evaluation)
The test results of the sealing film were evaluated according to each criterion, and the following criteria were used as comprehensive evaluation.
○: When all the test items are ○: Δ: When all or some of the test items have △, but there is no X ×: When all or some of the test items have “X”.

(15) Evaluation of output of solar cell module Based on JIS C8917-1998, an environmental test of the solar cell module was performed, and the output of the photovoltaic power before and after the test was measured and indicated by the following output reduction rate (%). The output reduction rate is determined according to the following criteria, and if it is ◯ or Δ, it is a pass.
{(Photovoltaic value before test) − (Photovoltaic value after test)} / (Photovoltaic value before test) × 100 (%)
○: Output reduction rate is less than 7% Δ: Output reduction rate is 7% or more and less than 10% ×: Output reduction rate is 10% or more.

<Example 1>
(1) Polymerization of PPS Sodium sulfide 32 kg (250 mol, containing 40% by mass of crystal water), sodium hydroxide 100 g, sodium benzoate 36.1 kg (250 mol), and N-methyl-2-pyrrolidone (hereinafter referred to as autoclave) 79.2 kg (abbreviated as NMP) was charged, and the temperature was gradually raised to 205 ° C. while stirring, and 7.0 liters of distillate containing 6.9 kg of water was removed. To the residual mixture, 37.5 kg (255 mol) of 1,4-dichlorobenzene (hereinafter abbreviated as DCB) and 20 kg of NMP were added and polymerized at 250 ° C. for 5 hours. The obtained reaction product was washed 8 times alternately with hot water using ion-exchanged water and NMP, and dried in a vacuum dryer at 80 ° C. for 24 hours. The resulting PPS powder polymer had a melt viscosity of 4100 poise, a glass transition temperature of 90 ° C., and a melting point of 285 ° C.

(2) Preparation of PPS resin composition To the PPS powder obtained in (1) above, an ethylene glycol slurry of heavy calcium carbonate having an equal number N of 7.5 and an average particle diameter of 1.1 μm according to Rosin-Lambler distribution ( 40 parts by mass of a solid concentration of 50% by mass) was added, and the mixture was stirred and mixed at 50 ° C. at high speed using a Henschel mixer. This mixture was melted at a temperature of 320 ° C. with a counter-rotating twin-screw extruder having a single-stage vent hole, and ethylene glycol was removed from the melted PPS resin at the vent portion. After that, it was pushed out from a 3 mmφ die in a goat shape, cooled in water and then cut short to prepare PPS resin composition pellets. Let the obtained PPS resin composition be PPS-1. The polymer contained 16.8% by mass of calcium carbonate based on the PPS polymer.

(3) Production of Low Specific Gravity Biaxially Oriented PPS Film PPS-1 obtained in (2) above was dried at 180 ° C. under reduced pressure at 10 mmHg for 3 hours, and melted at a temperature of 310 ° C. with a 40 mm aperture extruder. , Filtered through a metal fiber filter (95% cut hole diameter 10 μm), extruded from a T-die having a straight lip 400 mm long and 1.5 mm wide, and cast on a metal drum maintained at a surface temperature of 25 ° C. And solidified by cooling to obtain an unstretched sheet having a thickness of 1100 μm. Next, the film is guided to a stretching apparatus composed of a roll group, and the film temperature is stretched 3.7 times at a temperature of 99 ° C. and a stretching speed of 30000% / min. The film was stretched at a stretching temperature of 1000 ° C. and a stretching ratio of 3.5 times, and further heat-treated at a temperature of 270 ° C. for 10 seconds in a subsequent heat treatment chamber in the same tenter to perform 5% relaxation in the width direction. The film thus obtained had a thickness of 100 μm. The apparent specific gravity of this film was 0.65, and the deformation rate of the film was 34%. This film is designated PPSF-1.

(4) Adjustment of resin film layer
(A) Production of PET film
Ethylene glycol (64 parts) was mixed with dimethyl terephthalate (100 parts by mass), and 0.06 parts of magnesium acetate and 0.03 part of antimony trioxide were added as catalysts, and the temperature was raised to 150 to 235 ° C. An exchange reaction was performed.

  0.02 part of trimethyl phosphate was added thereto, and the temperature was gradually raised and reduced, and polymerization was carried out at a temperature of 285 ° C. for 3 hours. The intrinsic viscosity [η] of the obtained polyethylene terephthalate (PET) was 0.57. This polymer was cut into chips having a length of 4 mm.

  The PET having an intrinsic viscosity [η] of 0.57 obtained above was placed in a rotary heating vacuum apparatus (rotary dryer) having a temperature of 220 ° C. and a vacuum degree of 0.5 mmHg, and heated for 20 hours with stirring. The intrinsic viscosity of the PET thus obtained was 0.75. This polymer is designated as PET-1.

  A master chip containing 10% by mass of silica (particle size: 0.3 μm) was mixed with PET-1 in an amount of 0.1% by mass with stirring using a mixer, and then the temperature was 180 ° C. and the degree of vacuum was 0. It was vacuum dried at 0.5 mmHg for 3 hours, cast into a 90 mm caliber melt extruder and electrostatically adhered to a cooling drum maintained at 25 ° C. The extrusion temperature was 270-290 ° C. The thickness of the obtained sheet was 550 μm. This sheet was stretched 3.0 times in the longitudinal direction of the film at a temperature of 90 ° C. by successive biaxial stretching, then the film was supplied to the subsequent tenter and stretched 3.0 times in the width direction at a temperature of 95 ° C. . Furthermore, it heat-processed at the temperature of 220 degreeC in the same tenter after that, and relaxed 5% in the width direction. The film thus obtained has a thickness of 50 μm and is designated as PETF-1.

(B) Production of Resin Film Layer PPS-F-1 and PET-F-1 obtained above were laminated in a two-layer configuration of PPSF-1 / PET-1 via the following adhesive. In the lamination, the adhesive was applied to one surface of PET-F-1 by the gravure coater method, and the adhesive coating thickness was adjusted to 5 μm after drying the solvent. The drying conditions were 100 ° C. and 5 minutes. The lamination method was a hot press roll method, the temperature was 100 ° C., and the pressure was 2 kg linear pressure. Further, the adhesive was cured for 3 days at a temperature of 40 ° C. (referred to as resin film-1).
Adhesive: A urethane-based adhesive (manufactured by Toyo Morton Co., Ltd .: Adcoat 76P1) was used, and the mixing ratio of the main agent and the curing agent was 100/1, and the coating agent concentration was adjusted to 25% by mass. Further, ethyl acetate was used as a solvent for dilution.

(5) Production of Gas Barrier Layer A 12 μm thick PET film (Toray Lumirror (registered trademark) S10) was used as a gas barrier layer support film, and a silicon oxide film having a thickness of 800 angstroms was formed on this film by sputtering ( Gas barrier layer-1).

(6) Manufacture of solar cell module sealing film Adhesive in the same manner as in (4)-(b) above, with the silicon oxide layer being the inner surface on the PET surface of resin film-1 obtained previously. Laminated. Water vapor permeability of the sealing film obtained thus was was 0.5g ^/ m 2 ^/ 24hr (a sealing film -1).

<Example 2>
Using heavy calcium carbonate having an equal number of 7.1 and an average particle size of 1.5 μm by the method of Example 1 for the PPS polymer obtained in Example 1, the concentration of calcium carbonate added was 16.8. A weight% PPS resin composition (PPS-2) was obtained.

  Using this PPS-2, a low specific gravity biaxially oriented PPS film having a thickness of 100 μm was obtained by the method of Example 1 (this film is referred to as PPSF-2). The apparent specific gravity of the film was 0.77, and the deformation rate of the film was 24%.

  Furthermore, it processed into the sealing film for solar cell modules by the method of Example 1, and the same conditions using this PPSF-2, PETF-1 used in Example 1, and a gas burr layer-1. Let the obtained sealing film be sealing film-2.

<Example 3>
Heavy calcium carbonate having an equal number of 6.9 and an average particle diameter of 1.1 μm was used for the PPS polymer obtained in Example 1 by the method of Example 1, and the amount of calcium carbonate added was 16.8. It adjusted so that it might become weight%.
The PPS resin composition thus obtained is designated as PPS-3.

  Next, using this PPS-3, a PPS film having a thickness of 100 μm (the film is referred to as PPSF-3) was obtained by the method of Example 1. The apparent specific gravity of this film was 1.10, and the deformation rate of the film was 18%.

  Furthermore, the sealing film for solar cell modules was comprised for this film and PETF-1 and gas barrier layer-1 which were used in Example 1 by the same method and the same conditions as Example 1. Let the obtained sealing film be sealing film-3.

<Example 4>
Using heavy calcium carbonate having an equal number of 8.3 and an average particle size of 0.6 μm by the method of Example 1 to the PPS polymer obtained in Example 1, the amount of calcium carbonate added was 11.0. It adjusted so that it might become weight%.
The PPS resin composition thus obtained is designated PPS-4.

  Next, using this PPS-4, a PPS film having a thickness of 100 μm was obtained by the method of Example 1 (this film is referred to as PPSF-4). The apparent specific gravity of this film was 1.26, and the deformation rate of the film was 11%.

  Furthermore, the sealing film for solar cell modules was comprised for this film and PETF-1 and gas barrier layer-1 which were used in Example 1 by the same method and the same conditions as Example 1. Let the obtained sealing film be sealing film-4.

<Comparative Example 1>
A PPS resin composition (PPS-5) was obtained in the same manner as in Example 1 using heavy calcium carbonate having an equal number of 7.5 and an average particle size of 1.1 μm. The amount of the outer particles added to the composition was adjusted to 6.5% by weight.

  Next, using this PPS-5, a PPS film having a thickness of 100 μm (hereinafter referred to as PPSF-5) was obtained by the method of Example 1. The apparent specific gravity of this film was 1.33, and the deformation rate of the film was 5%.

  Furthermore, the sealing film for solar cell modules was created by PETF-1 and gas barrier layer-1 which were used in Example 1 and the same method and conditions as Example 1. Let the obtained sealing film be sealing film-5.

<Comparative Example 2>
A PET film having a thickness of 200 μm was obtained by the method of Example 1. This film is designated as PETF-2. Using this film and the gas barrier layer-1, a sealing film for a solar cell module in which the resin film layer was only a PET film was prepared by the method and conditions of Example 1. Let this sealing film be sealing film-6.

<Comparative Example 3>
Transesterification was carried out according to a conventional method using 100 parts by mass of dimethylene terephthalate, 64 parts by mass of ethylene glycol and 0.09 parts by mass of calcium acetate, and an ethylene glycol solution containing 0.20% by mass of trimethyl phosphate was added. An ethylene glycol slurry containing 12% by mass of 1 μm calcium carbonate was added, and 0.03% by mass of antimony trioxide was added to obtain a 0.58 PET polymer (referred to as PET-2).

  The polymer was stretched by the same method as PETF-1 in Example 1, with a stretching temperature of 92 ° C. on both axes, a stretching ratio of 2.9 times in length, and 3.0 times in width. Other conditions were the same as PETF-1 of Example 1, and a film having a thickness of 100 μm was obtained. This film had an apparent specific gravity of 1.02. The deformation amount of the film was 25%. This film is designated as PETF-3.

  Next, a sealing film for a solar cell module was prepared using the same method and conditions as in Example 1 using PETF-1, the PETF-3, and the gas barrier layer-1 obtained in Example 1 (referred to as sealing film-7). ).

<Example 5>
Using PPS-3 of Example 3, a low specific gravity PPS film (PPSF-6) having a thickness of 15 μm was obtained in the same manner as in Example 3. In addition, a PET film having a thickness of 135 μm was obtained by the method of Example 1 using PET-1 of Example 1 (PETF-4). Next, using the PPSF-6, PETF-4, and gas barrier layer-1, a solar cell module sealing film was prepared in the same manner as in Example 1 (referred to as sealing film-8).

<Example 6>
By the method of Example 5, a PPS film (PPSF-7) having a thickness of 50 μm and a PET film (PETF-5) having a thickness of 100 μm were obtained. Moreover, the sealing film for solar cell modules was created with these films and gas barrier layer-1 similarly to Example 5 (it is set as sealing film-9).

<Example 7>
Using PPS-5 of Comparative Example 1, a biaxially oriented PPS film having a thickness of 50 μm was obtained by the method of Comparative Example 1 (referred to as PPSF-7). This film, PPSF-7 of Example 6, PETF-1 of Example 1, and gas barrier layer-1 were laminated in this order by the method of Example 1 to obtain a solar cell module sealing film (sealing film) −10).

<Examples 10 to 16, Comparative Examples 4 to 6>
A solar cell module is manufactured using the sealing film for solar cell modules of the sealing films-1 to 10 of Examples 1 to 7 and Comparative Examples 1 to 3.
A flat glass (manufactured by Asahi Glass: float plate glass) generally called white plate glass having a thickness of 4 mm was prepared for the front sheet layer. 400 μm thick EVA sheet / solar cell element (PIN type solar cell element bonded with a bonding film) / 400 μm thick EVA sheet / glass plate on the gas barrier layer side of each sealing film, A simple lead wire was taken and thermocompression bonded by a known vacuum laminating method. The laminating temperature was 150 ° C. The relationship between the 10 types of solar cell modules thus obtained and the sealing film used is shown in Table 1.

  The results of evaluation of each example and comparative example are shown in comparison with Tables 2 to 5.

(Summary)
Tables 2 to 4 show the results of evaluation of the solar cell module sealing film of the present invention, and Table 5 shows the results of evaluation of the solar cell module of the present invention. The sealing film for solar cell module of the present invention uses a biaxially oriented foamed PPS film excellent in heat resistance, hydrolysis resistance, chemical resistance, etc., under severe use environment (high temperature, high humidity, harmful In a gas atmosphere, etc., the reduction in the output of the solar cell module can be suppressed, and the insulation can be significantly improved. It can be seen that a film is obtained.

  The sealing films of Examples 1 to 4 and Comparative Example 1 were obtained by using resin films composed of a biaxially oriented foamed PPS film and a biaxially oriented PET film. This is an evaluation of the relationship between the degree of foaming (apparent specific gravity, thickness change rate), insulation and mechanical strength. As the apparent specific gravity decreases and the degree of foaming increases, the electrical insulation voltage intended by the present invention is improved and the insulation is increased. On the contrary, the deformation rate in the thickness direction of the film increases, the mechanical strength as the sealing film decreases, and the workability of the sealing film also decreases. That is, it is understood that the apparent specific gravity is particularly preferably in the range of 0.60 to 1.30 (more preferably 0.60 to 1.20) from the insulating properties, mechanical strength, and workability. Moreover, it turns out that it is excellent in heat resistance, hydrolysis resistance, and poisonous gas resistance compared with the sealing film which consists of a resin film of the PET film single film of the comparative example 2 and the comparative example 3. Sealing film-7 using the foamed PET film of Comparative Example 3 has an effect of improving insulation by the foamed layer, but has poor environmental resistance, and is not suitable for use in severe environments. Examples 5 and 6 (sealing films-8 and 9) are obtained by changing the lamination ratio (A / B) of the PPS film of the present invention with respect to the thickness of the resin film. As compared with the sealing film-3 of Example 3 using a PPS film having the same apparent specific gravity, it can be seen that the insulation improvement effect decreases and the resistance to severe environments decreases as the lamination ratio decreases. That is, in order to efficiently achieve the object of the present invention, the lamination ratio is preferably 10% or more. In addition, Example 7 shows that the object of the present invention can be achieved even when a PPS film having a low apparent specific gravity and a PPS film having a high specific gravity and a low foaming degree are used.

  Although the characteristics of the solar cell module were evaluated using the sealing film of the present invention and the sealing film of the comparative example (10 types of solar cell modules of Examples 10 to 16 and Comparative Examples 4 to 6), the sealing of the present invention It was confirmed that the solar cell module using the stop film is excellent in insulation, has a small output reduction, and is a much better solar cell module than the conventional one.

  The present invention relates to a sealing film for a solar cell module and a solar cell module using the sealing film. More specifically, the present invention significantly improves durability (hydrolysis resistance, harmful gas resistance, etc.) with high voltage compatibility. It is related with the sealing film for solar cell modules excellent in long-term reliability, and the solar cell module using the same.

This figure shows the basic structure of the sealing film for solar cell modules of the present invention. This figure shows an example of the configuration of the solar cell module of the present invention.

Explanation of symbols

1: Front sheet layer 2: Filling adhesive resin layer 3: Solar cell element 4: Back sheet layer 41: Gas barrier layer 42: Resin film layer 42a: Film layer 42b other than biaxially oriented foamed polyphenylene sulfide film: Biaxially oriented foamed polyphenylene Sulfide film

Claims (3)

  At least (i) a resin film layer comprising a biaxially oriented foam film, and (ii) a layer composed of at least one selected from the group consisting of metals, metal oxides, inorganic compounds and organic compounds. The biaxially oriented foamed film is a biaxially oriented foamed film having an apparent specific gravity (ρ) of 0.60 to 1.30, which is composed of a resin composition containing poly-p-phenylene sulfide as a main component. Sealing film for battery modules.   2. The solar cell according to claim 1, wherein a ratio (lamination ratio: B / A × 100) of the thickness (B) of the biaxially oriented foamed film to the thickness (A) of the entire resin film layer is 10% or more. Module sealing film.   The solar cell module comprised using the sealing film for solar cell modules of Claim 1 or 2.

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