JP5974580B2 - Manufacturing method of solar cell module - Google Patents

Description

  The present invention relates to a method for manufacturing a solar cell module.

  In recent years, people's awareness of ecology has increased, and expectations for solar cells, which are clean energy, have been increasing, and various types of solar cells have been developed. Among these solar cells, a thin-film solar cell such as an amorphous silicon solar cell in which silicon is deposited on a conductive substrate and a conductive layer is formed thereon is lightweight and excellent in flexibility and has good usability. Application as a thin film solar cell module is expected.

  As such a solar cell module, for example, in Patent Document 1, a back coating material, a filler, a filler holding material, a solar cell element, a filler holding material, a filler, and a surface coating material are laminated in this order, and 150 ° C. A solar cell module manufactured by heat laminating is disclosed.

Japanese Patent Application Laid-Open No. 09-92848

  In Patent Document 1, a weather-resistant transparent resin plate such as polycarbonate (PC) is used for the back surface covering material. When the present inventors examined in detail, the solar cell module of patent document 1 discovered the phenomenon that a solar cell characteristic, especially a fill factor (FF) fall. It has also been found that this phenomenon is remarkable when a thin film solar cell element is used as the solar cell element. The present invention solves such a problem.

The inventors of the present invention have made extensive studies to solve the above problems, and have focused on the relationship between the thermal laminate and the back coating material (resin substrate). Then, the resin substrate may expand due to thermal lamination when manufacturing the solar cell module, and the resin substrate may contract due to subsequent cooling, and the contraction force of the resin substrate damages the solar cell element, resulting in the sun. The knowledge that the performance as a battery is reduced was obtained. In addition, wrinkles occur on the light receiving surface side of the solar cell module due to the expansion and contraction of the layers constituting the solar cell module due to the heat at the time of manufacturing the solar cell module by thermal lamination, and the design property is improved. The knowledge that it reduces was obtained.
This phenomenon is remarkable when a thin-film solar cell element that is weak against external stress, particularly compressive stress, is used.

Therefore, the present inventors have conducted extensive research based on the above findings, and by performing thermal lamination at the time of manufacturing a solar cell module at a temperature lower than the glass transition temperature Tg of the resin substrate, the solar cell performance can be improved. It was conceived that generation of wrinkles could be suppressed by thermally laminating the sealing layer on the surface protective layer side so that the gelation rate was 50% or more, and the present invention was completed. The present invention
In the step of manufacturing a laminate having a resin substrate, a sealing layer, a thin-film solar cell element, a sealing layer, and a weather resistant layer in this order, a method for manufacturing a solar cell module, comprising: thermally laminating the laminate The laminating step is performed at a temperature lower than the glass transition temperature Tg of the resin substrate so that the gelation rate of the sealing layer between the weather resistant layer and the thin film solar cell is 50% or more. A method for manufacturing a solar cell module.

  In addition, the resin substrate preferably has a Young's modulus at 25 ° C. of 500 MPa or more and a film thickness of 100 μm or more.

  Moreover, it is preferable that the resin substrate is a polycarbonate resin or an acrylic resin. Moreover, it is a preferable aspect that the laminating step is performed at a temperature lower by 5 ° C. or more than the glass transition temperature Tg of the resin substrate.

  Moreover, it is a preferable aspect that the sealing layer is an ethylene-vinyl acetate copolymer (EVA) having a gelation rate of 70% or more when held at 130 ° C. for 45 minutes.

  Moreover, it is a preferable aspect that the said laminated body manufacturing process laminates | stacks a back surface protective layer, a mold release layer, a resin substrate, a sealing layer, a thin film solar cell element, a sealing layer, and a weather resistant layer in this order.

  Another aspect of the present invention is a solar cell module including a back surface protective layer, a release layer, a resin substrate, a sealing layer, a thin-film solar cell element, a sealing layer, and a weather resistant layer. It is preferable that the gelation rate of the sealing layer between the thin-film solar cell element and the weather resistant layer is 50% or more.

  According to the manufacturing method of the present invention, it is possible to provide a solar cell module that prevents a decrease in solar cell performance, particularly a fill factor (FF), and suppresses generation of wrinkles generated on the light receiving surface side of the solar cell module. Furthermore, it is possible to provide a solar cell module in which warpage due to thermal lamination is suppressed.

It is a schematic diagram of one embodiment of the solar cell module of the present invention. It is a schematic diagram of one embodiment of the solar cell module of the present invention.

  The method for producing a solar cell module of the present invention includes a step of thermally laminating the laminate in the step of producing a laminate having a resin substrate, a sealing layer, a thin film solar cell element, a sealing layer, and a weather resistant layer in this order. It is a manufacturing method including. Then, the laminating step is performed at a temperature lower than the glass transition temperature (Tg) of the resin substrate, and the gelation rate of the sealing layer between the thin-film solar cell element and the weathering layer is 50% or more. It is characterized by heat lamination.

<Lamination process>
The production method of the present invention is a method for producing a solar cell module by thermal lamination. A method for producing a solar cell module by thermally laminating the laminate produced in the step of producing a laminate is preferred. There is no particular limitation on the method of thermal lamination, and it can be carried out using a laminating machine that is usually used.
In the laminating step of the present invention, the gelation rate of the sealing layer between the weather resistant layer and the thin-film solar cell is 50% or more at a temperature lower than the glass transition temperature Tg of the resin substrate included in the laminate. Do.
When laminating at a temperature exceeding the Tg of the resin substrate, the resin substrate thermally expands. Therefore, the resin substrate in a thermally expanded state and the sealing layer or thin film solar cell element laminated on the resin substrate are bonded together by lamination. The laminated body is then cooled to room temperature, but some resin substrates that have expanded due to cooling contract. When the thermally expanded resin substrate is contracted, the force to be contracted is also transmitted to the laminated thin film solar cell element, which causes the thin film solar cell element to be deformed, leading to a decrease in performance, particularly a decrease in fill factor. The present inventors have found that.

  The present inventors can suppress the expansion, contraction, and deformation of the resin substrate and prevent the performance of the solar cell element from being deteriorated by performing the laminating process at a temperature lower than the glass transition temperature Tg of the resin substrate to be used. I came up with what I can do. The lamination temperature is preferably 5 ° C. or more lower than the glass transition temperature Tg of the resin substrate, more preferably 10 ° C. or more, more preferably 13 ° C. or more from the viewpoint of further suppressing expansion of the resin substrate. It is more preferable to carry out at a low temperature, and it is particularly preferable to carry out at a temperature lower by 20 ° C. or more. On the other hand, the lower limit of the laminating temperature is not particularly limited as long as it is a temperature at which heat laminating is possible, but is usually 80 ° C. or higher, and more preferably 110 ° C. or higher.

Furthermore, even when the laminating step is performed at a temperature lower than the glass transition temperature Tg of the resin substrate to be used, if the gelation rate of the sealing layer between the weather resistant layer and the thin film solar cell element is less than 50%, the laminate The present inventors have found that wrinkles are likely to occur in the solar cell module due to thermal expansion and contraction of each layer constituting the laminate by heat in the process.
And the present inventors suppress generation | occurrence | production of the wrinkle of a solar cell module by performing a lamination process so that the gelatinization rate of the sealing layer between a weather resistance layer and a thin film solar cell element may be 50% or more. I came up with it. The gelation rate of the sealing layer between the weather resistant layer and the thin film solar cell element is preferably 55% or more, more preferably 60% or more, still more preferably 70% or more, and most preferably 80% or more.
In the manufacturing method of this invention, generation | occurrence | production of the wrinkle by the side of the light-receiving surface of a solar cell module can be suppressed by making the gelatinization rate of the sealing layer between a weather resistant layer and a thin film solar cell element into the said range.
The wrinkles generated in the solar cell module at the time of thermal lamination can occur between the layers and layers constituting the solar cell module. Specifically, for example, wrinkles due to shrinkage of the weather-resistant layer upon cooling after lamination, wrinkles due to expansion / contraction of the sealing layer, one adjacent when there is a large difference in thermal expansion / contraction between adjacent layers, or Examples include wrinkles that occur in both layers.
The sealing layer not only functions to seal the thin film solar cell element, but also in the configuration of the solar cell module of the present invention, between the resin substrate and the thin film solar cell element, and between the thin film solar cell element and the weather resistant layer. By adhering each layer constituting the solar cell module, it has a function of suppressing expansion and contraction of each layer due to thermal lamination, and by making the gelation rate of the sealing layer within the scope of the present invention, Generation of wrinkles can be suppressed. In particular, when wrinkles are generated on the light receiving surface side of the solar cell element, not only the design is deteriorated, but when the amount is large, the transmittance is lowered and the power generation efficiency of the solar cell module is lowered. According to the present invention, these problems can be solved.
The gelation rate of the sealing layer can be adjusted by the composition of the sealing material described later and the thermal lamination conditions. In order to adjust the gelation rate under the thermal lamination conditions, the temperature of the thermal lamination is set to the above temperature. What is necessary is just to raise as much as possible in the range, and to lengthen the lamination time. In addition, the time of thermal lamination here means the integration | accumulation of the time when the sealing layer between a weather-resistant layer and a thin film solar cell element was provided to thermal lamination.

In the laminating step of the present invention, laminating is performed at a temperature lower than the glass transition temperature Tg of the resin substrate used, and the gelation rate of the sealing layer between the weather resistant layer and the thin film solar cell element is in the above range. Other than the above, there is no particular limitation, but the laminating step is preferably performed under vacuum conditions. Usually, the degree of vacuum is 30 Pa or more, preferably 50 Pa or more, more preferably 70 Pa or more. On the other hand, the upper limit is usually 150 Pa or less, preferably 120 Pa or less, more preferably 100 Pa or less. By setting it as the said range, since generation | occurrence | production of a bubble can be suppressed in each layer in a module and productivity is also improved, it is preferable.
The vacuum time is usually 20 seconds or longer, preferably 30 seconds or longer, more preferably 1 minute or longer. On the other hand, the upper limit is usually 15 minutes or less, preferably 12 minutes or less, more preferably 10 minutes or less. Setting the vacuum time in the above range is preferable because the appearance of the solar cell module after heat lamination becomes good and the generation of bubbles in each layer in the module can be suppressed.

The pressurizing condition of the thermal laminate is usually a pressure of 50 kPa or more, preferably 70 kPa or more, more preferably 90 kPa or more. On the other hand, the upper limit is usually 150 kPa or less, preferably 110 kPa or less. By setting it as the pressurization conditions of the said range, since moderate adhesiveness can be acquired, without damaging a solar cell module, it is preferable also from a durable viewpoint.
The holding time of the pressure is usually 1 minute or longer, preferably 3 minutes or longer, more preferably 5 minutes or longer. On the other hand, the upper limit is usually 2 hours or less, preferably 90 minutes or less, more preferably 60 minutes or less. By setting the above holding time, the gelation rate of the sealing layer can be made appropriate, so that the function of protecting the thin film solar cell element of the sealing layer can be sufficiently exhibited, and sufficient adhesive strength Can be obtained.

The heating time of the thermal laminate is usually 10 minutes or longer, preferably 12 minutes or longer, more preferably 15 minutes or longer. On the other hand, the upper limit is 2 hours or less, preferably 90 minutes or less, more preferably 60 minutes or less. By setting it as the said heating time, since a sealing layer is bridge | crosslinked moderately, durability performance improves and it can have moderate softness | flexibility, and is preferable.
The pressurization and heating of the heat laminate may be performed simultaneously. Further, heating may be performed while maintaining the pressure after pressing.

  In the method for producing a solar cell module of the present invention, the step of producing the laminate is a laminate having a resin substrate, a sealing layer, a thin film solar cell element, a sealing layer, and a weather resistant layer in this order, preferably the back surface. The laminate may be manufactured by any method as long as a laminate having a protective layer, a release layer, a resin substrate, a sealing layer, a thin film solar cell element, a sealing layer, and a weather resistant layer can be manufactured in this order. The method is not particularly limited, and all the layers may be laminated simultaneously or stepwise. Above all, a step of producing a pre-laminated body by previously laminating layers other than a resin substrate (in a preferred embodiment, a back surface protective layer, a release layer and a resin substrate), specifically, an upper module which is a pre-laminated body by thermal lamination It is preferable to include a preliminary laminating step for manufacturing. The upper module includes at least a sealing layer, a thin film solar cell element, and a sealing layer, and preferably includes a weather resistant layer, a sealing layer, a thin film solar cell element, and a sealing layer. After the upper module is manufactured by the preliminary laminating step, the upper module and the resin substrate can be laminated to obtain a laminate. By including the preliminary laminating step, the manufacturing process can be easily managed with respect to the change in the type of the resin substrate.

Since the preliminary laminating step is performed in a state where the resin substrate is not laminated, various conditions such as temperature, pressure, vacuum time, and laminating time may be appropriately set according to general lamination.
By adopting the method of the present invention, it is preferable because the performance (particularly the fill factor) of the solar cell module can be improved and wrinkles on the light receiving surface of the solar cell module can be suppressed.

<Resin substrate>
As the resin substrate used in the laminate manufacturing process of the present invention, a widely used resin can be used. Specific types of resin include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), nylon, polyethersulfone (PES), polycarbonate (PC), polyethylene (PE), polypropylene (PP), acrylic resin, urethane Examples thereof include plastics such as resins and fluororesins.

  The resin used for the resin substrate preferably has a glass transition temperature Tg of 150 ° C. or lower, and more preferably 140 ° C. or lower. Moreover, it is preferable that Tg of resin is 70 degreeC or more, and it is preferable that it is 80 degreeC or more. When Tg is in the above range, the solar cell module has an appropriate flexibility during lamination and excellent workability. The glass transition point Tg is measured by DSC measurement.

  The resin used for the resin substrate usually has a weight average molecular weight (Mw) of 10,000 or more. Although an upper limit is not limited, 70000 or less are preferable and it is more preferable that it is 20000 or less. The weight average molecular weight in the present invention is determined by SEC (size exclusion chromatography) measurement. In SEC measurement, the elution time is shorter for higher molecular weight components and the elution time is longer for lower molecular weight components, but using the calibration curve calculated from the elution time of polystyrene (standard sample) with a known molecular weight, the elution time of the sample is changed to the molecular weight. The weight average molecular weight is calculated by conversion.

  In addition, the resin used for the resin substrate preferably has a Young's modulus at 25 ° C. of 500 MPa or more. In the present invention, it is possible to prevent the resin from expanding as much as possible by laminating at a temperature equal to or lower than the Tg of the resin, and it is possible to prevent the performance degradation of the solar cell element. When using a resin substrate that generates a large shrinkage force during cooling, such as is less than 500 MPa, the performance of the thin-film solar cell element is significantly deteriorated when thermally laminated at a temperature of Tg or higher. Is particularly prominent. Preferably, the Young's modulus at 25 ° C. is 2000 MPa or more. On the other hand, the upper limit of the Young's modulus of the resin substrate is not particularly limited, but the Young's modulus at 25 ° C. is usually 4000 MPa or less, and preferably the Young's modulus at 25 ° C. is 2400 MPa or less.

  Furthermore, the film thickness of the resin substrate is preferably 100 μm or more, and more preferably 1000 μm or more. Even when the film thickness is thick, the force that the expanded resin substrate contracts becomes stronger, and the performance of the solar cell element is likely to deteriorate. Therefore, the effect of the present invention is remarkable when a resin substrate that generates a large shrinkage force during cooling, such as a film thickness of the resin substrate of 1800 μm or more, is used. On the other hand, the present invention is a thin film solar cell, and the upper limit of the film thickness is usually 5000 μm or less, preferably 3000 μm or less.

  Specific examples of the resin substrate preferably used in the production method of the present invention include polycarbonate resin and acrylic resin.

  The Young's modulus is a value measured according to a JIS-K7161 tensile test. For the measurement, a single column type tensile compression tester manufactured by A & D was used.

<Sealing layer>
The sealing layer used for the laminated body manufacturing process of this invention is provided so that a solar cell element may be covered among solar cell modules for the purpose of sealing a thin film solar cell element. As this sealing layer, resin materials having relatively high solar transmittance, such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer Polyolefin resin such as coalescence, propylene / ethylene / α-olefin copolymer, butyral resin, styrene resin, epoxy resin, (meth) acrylic resin, urethane resin, silicone resin, synthetic rubber, etc. can be used. One or more mixtures or copolymers can be used. Of these, ethylene-vinyl acetate copolymer (EVA) is preferable.

The thickness of the sealing layer is preferably 100 μm or more, more preferably 200 μm or more, and further preferably 300 μm or more. On the other hand, it is preferably 1000 μm or less, more preferably 800 μm or less, and even more preferably 500 μm or less. By setting the thickness of the sealing layer within the above range, moderate impact resistance can be obtained, and it is preferable from the viewpoint of cost and weight, and power generation characteristics can be sufficiently exhibited.

As the sealing layer, it is preferable to use an ethylene-vinyl acetate copolymer (EVA), and it is more preferable to use EVA having a gelation rate of 70% or more when held at 130 ° C. for 45 minutes. More preferably, it is 80% or more, More preferably, it is 90% or more. Further, it is usually 99% or less, preferably 98% or less, more preferably 96% or less.
The manufacturing method of the present invention is characterized in that the thermal lamination is performed at a temperature lower than the Tg of the resin substrate. Therefore, although heat lamination is performed at a relatively low temperature, when the lamination is performed at a low temperature, EVA is not sufficiently crosslinked, and the protective function as a sealing layer may not be sufficiently exhibited. Therefore, it is preferable to use EVA having a gelation rate of 70% or more when held at 130 ° C. for 45 minutes, because EVA cross-linking proceeds sufficiently even at a low temperature laminate.
In the present invention, the sealing layer between the weathering layer and the thin-film solar cell element is thermally laminated so that the gelation rate of the sealing layer is 50% or more. In order to adjust the gelation rate of the sealing layer, The method of mixing a crosslinking agent, a peroxide, a silane coupling agent, etc. with the resin material used for a sealing layer is mentioned. The crosslinking agent, peroxide, and silane coupling agent are not particularly limited as long as they promote the gelation of the resin material, and may be appropriately selected from known compounds. The amount to be mixed is not limited. Usually, the amount of the crosslinking agent to be mixed is 0.01 to 5% by weight with respect to the resin material, the amount of the peroxide is 0.01 to 5% by weight with respect to the resin material, and silane. The amount of the coupling agent is usually 0.01 to 5% by weight with respect to the resin material, and the sum of these is adjusted in the range of usually 0.01 to 10% by weight with respect to the resin material.
EVA having a gelation rate of 70% or more when held at 130 ° C. for 45 minutes can be produced by the same method.
The gelation rate of EVA in the present invention was determined by holding EVA at 45 ° C for 45 minutes, immersing it in toluene at 60 ° C for 4 hours, filtering and drying, and dividing the weight by the weight before immersion. Value.
The gel ratio of the sealing layer in the present invention refers to a value obtained by immersing the sealing layer after the lamination step in toluene at 60 ° C. for 4 hours, filtering and drying, measuring the weight, and dividing by the weight before the immersion.

<Thin film solar cell element>
The thin film solar cell element used in the present invention is composed of a power generation element that converts sunlight into electricity and a power generation element base material for suppressing a change in shape of the power generation element. In addition, a gas barrier layer, a wavelength conversion layer, and a UV absorption layer may be laminated as necessary.

(Power generation element)
The power generation element is an element that generates power based on sunlight incident from the weathering layer side. This power generation element can convert light energy into electric energy, and can extract the electric energy obtained by the conversion to the outside.

As a power generation element, a power generation layer (photoelectric conversion layer, light absorption layer) is sandwiched between a pair of electrodes, a stack of a power generation layer and another layer (buffer layer, etc.) is sandwiched between a pair of electrodes, and so on. A plurality of such things connected in series can be used.
Various power generation layers can be employed, but by using amorphous silicon or an organic semiconductor material, a thin (light) power generation element with relatively high power generation efficiency can be realized.

When the power generation element is an amorphous silicon layer, a solar cell element that has a large optical absorption coefficient in the visible region and can sufficiently absorb sunlight even with a thin film having a thickness of about 1 μm can be realized. Moreover, since amorphous silicon is an amorphous material, it is resistant to deformation. Therefore, when the power generation layer is an amorphous silicon layer, a particularly lightweight solar cell module having a certain degree of resistance to deformation can be realized.

  Further, as a specific configuration example of the organic semiconductor layer, a bulk heterojunction type having a layer (i layer) in which a p-type semiconductor and an n-type semiconductor are phase-separated in the layer, and a layer (p layer) each including a p-type semiconductor. And a layered type (hetero pn junction type) in which layers containing an n-type semiconductor (n layer) are stacked, a Schottky type, and a combination thereof.

Each electrode of the power generation element can be formed using one or more arbitrary materials having conductivity. Examples of the electrode material (electrode constituent material) include metals such as platinum, gold, silver, aluminum, chromium, nickel, copper, titanium, magnesium, calcium, barium, sodium, and alloys thereof; indium oxide and tin oxide Metal oxides such as, or alloys thereof (ITO: indium tin oxide); conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene; acids such as hydrochloric acid, sulfuric acid, sulfonic acid, A material containing a dopant such as a Lewis acid such as FeCl ₃ , a halogen atom such as iodine, or a metal atom such as sodium or potassium; conductive particles such as metal particles, carbon black, fullerene, or carbon nanotubes, and a matrix such as a polymer binder And conductive composite materials dispersed in the material.

  The electrode material is preferably a material suitable for collecting holes or electrons. Examples of the electrode material suitable for collecting holes (that is, a material having a high work function) include gold and ITO. Examples of the electrode material suitable for collecting electrons (that is, a material having a low work function) include silver and aluminum.

  Each electrode of the power generation element may be substantially the same size as the power generation layer or may be smaller than the power generation layer. However, if the electrode on the light receiving surface side (weatherproof layer side) of the power generation element is relatively large (the area is not sufficiently small compared to the area of the power generation layer), the electrode Should be a transparent (translucent) electrode, particularly an electrode having a relatively high transmittance (for example, 50% or more) of light having a wavelength that allows the power generation layer to efficiently convert it into electrical energy. . Examples of transparent electrode materials include oxides such as ITO and IZO (indium oxide-zinc oxide); metal thin films, and the like.

The thickness of each electrode of the power generation element and the thickness of the power generation layer can be determined based on the required output and the like.
Further, an auxiliary electrode may be provided so as to be in contact with the electrode. In particular, it is effective when using a slightly conductive electrode such as ITO. As the auxiliary electrode material, the same material as the above metal material can be used as long as the conductivity is good, but silver, aluminum, and copper are exemplified.

(Power generation element substrate)
The power generation element substrate used for the thin film solar cell element is a member on which one of the power generation elements is formed. Therefore, the power generating element base material is desired to have a relatively high mechanical strength, excellent weather resistance, heat resistance, chemical resistance, and the like, and lightweight. It is also desirable that the power generating element substrate has a certain degree of resistance against deformation. Therefore, it is preferable to employ a metal foil, a resin film having a melting point of 85 to 350 ° C., and some metal foil / resin film laminates as the power generation element substrate.

  Examples of the metal foil that can be used as the power generation element substrate (or its constituent elements) include foils made of aluminum, stainless steel, gold, silver, copper, titanium, nickel, iron, and alloys thereof. The resin film having a melting point of 85 to 350 ° C includes polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polycarbonate, polyacetal, acrylic resin, polyamide resin, ABS resin, ACS resin. , AES resin, ASA resin, copolymers thereof, fluorine resin such as PVDF, PVF, silicone resin, cellulose, nitrile resin, phenol resin, polyurethane, ionomer, polybutadiene, polybutylene, polymethylpentene, polyvinyl alcohol, polyarylate, Examples thereof include films made of polyetheretherketone, polyetherketone, polyethersulfone and the like. The resin film used as the power generation element substrate may be a film in which glass fiber, organic fiber, carbon fiber, or the like is dispersed in the resin as described above.

  In addition, it has been found from various experimental results that when the solar cell module is bent as the power generation element substrate, cracks are easily generated when the solar cell module is bent. ing. Therefore, the power generation element base material should be thinner than the sealing layer, and its thickness is 0.83 (= “1 / 1.2”) of the thickness of the sealing layer. It is preferable to adopt one that is less than or equal to double, more preferably to adopt one that is 0.67 (= 1 / 1.5) or less, and 0.5 times or less. It is particularly preferable to adopt what has been formed.

<Ankle layer>
The weather resistant layer used in the present invention is a layer for imparting mechanical strength, weather resistance, scratch resistance, chemical resistance, gas barrier properties and the like to the solar cell module. This weather-resistant layer is preferably one that does not interfere with light absorption of the power generation element, that is, one that transmits light having a wavelength that allows the power generation element to efficiently convert into electric energy. For example, the solar radiation transmittance is 80% or more. It is preferable that it is 85% or more.

  Moreover, since a solar cell module is heated by sunlight, it is preferable that a weather resistant layer has heat resistance. Therefore, the constituent material of the weather resistant layer preferably has a melting point of 100 ° C. or higher, and more preferably 120 ° C. or higher. On the other hand, the upper limit of the melting point is preferably 320 ° C. or lower.

The material for the weathering layer can be selected in consideration of these characteristics. For example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, polychlorinated Vinyl resins, fluorine resins, polyethylene resins such as polyethylene terephthalate, polyethylene naphthalate, phenol resins, polyacrylic resins, (hydrogenated) epoxy resins, polyamide resins such as various nylons, polyimide resins, polyamide-imide resins, polyurethane resins Cellulose resins, silicone resins, polycarbonate resins, and the like can be used as the constituent material of the weather resistant layer. Among these, from the viewpoint of weather resistance, it is preferable to use a fluorine-based resin such as ETFE (tetrafluoroethylene and ethylene copolymer).
The weather resistant layer may be composed of two or more materials. The weather resistant layer may be a single layer or a laminate composed of two or more layers. Further, if necessary, the laminated surface may be subjected to surface treatment such as corona treatment, plasma treatment, ozone treatment, UV irradiation, electron beam irradiation, or flame treatment.

  The thickness of the weathering layer is not particularly defined, but the mechanical strength tends to increase by increasing the thickness, and the flexibility tends to increase by decreasing the thickness. Therefore, the thickness of the weather resistant layer is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less. In short, as the weather resistant layer, various thickness layers made of materials having weather resistance, heat resistance and the like can be adopted.

<Release layer>
In the laminate used in the production method of the present invention, a release layer and a back surface protective layer are preferably provided on the surface of the resin substrate opposite to the thin film solar cell side, that is, on the back surface of the resin substrate.
The release layer used in the present invention is laminated on the back side of the resin substrate in the solar cell module, adhered to the resin substrate with an adhesive force that does not drop by thermal lamination, and can be easily peeled off from the resin substrate during construction. Is. Therefore, it is necessary to adhere to the resin substrate with a certain force that does not completely weld to the resin substrate and does not peel off due to its own weight. By providing such a release layer by laminating with a back surface protective layer described later, warpage of the solar cell module due to thermal lamination can be suppressed. In addition, it is possible to prevent the back surface of the resin substrate from being damaged from the time of manufacture of the solar cell module to the time of construction.

The resin used for the release layer is melted by thermal lamination in relation to the resin substrate and is not integrated with the resin substrate, and is bonded to the resin substrate with an appropriate adhesive force. Select one that integrates with the backside protective layer by thermal lamination. The resin having such properties can be appropriately selected from olefin resin, acrylic resin, silicone resin, and the like.
The thickness of the release layer is not particularly limited, but is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, more preferably 10 μm or more, and usually 100 μm or less, preferably 80 μm or less, more preferably 50 μm or less. .

Moreover, when a resin having a high Young's modulus is used in the light-receiving side laminated portion in the solar cell module, that is, the rust-proof layer, the sealing layer, the thin-film solar cell element, and the sealing layer that are located on the solar side from the resin substrate It is preferable to increase the Young's modulus of the resin used for the release layer. By setting it as such an aspect, the curvature of the manufactured solar cell module can be prevented.
The appropriate Young's modulus of the release layer varies depending on the types of the weathering layer, the sealing layer, and the thin-film solar cell element. Specifically, it is preferably 100 MPa or more, more preferably 200 MPa or more, and still more preferably 400 MPa or more. Moreover, 3000 MPa or less is preferable, 2000 MPa or less is more preferable, and 1000 MPa or less is still more preferable.

  The peel strength between the release layer and the resin substrate may be such that it does not peel off due to its own weight and can be easily peeled off at the time of construction. Specifically, it is preferably 5N / 25mm or more and 25N / 25mm or less, More preferably, it is 20 N / 25 mm or less.

<Back side protective layer>
The back surface protective layer of the present invention prevents scratches on the back surface of the resin substrate of the solar cell module, and imparts mechanical strength, scratch resistance, chemical resistance, gas barrier properties, light resistance, and the like. Of layers.
As the back surface protective layer, polyethylene resin, polypropylene resin, cyclic polyolefin resin, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, polyvinyl chloride resin, fluorine resin, polyethylene terephthalate, polyethylene naphthalate, etc. Polyester resins, phenol resins, polyacrylic resins, (hydrogenated) epoxy resins, polyamide resins such as various nylons, polyimide resins, polyamide-imide resins, polyurethane resins, cellulose resins, silicone resins, polycarbonate resins, etc. It can be used as a constituent material of the back surface protective layer. The back surface protective layer may be made of two or more materials.
The back protective layer is preferably a colored opaque layer. By being a colored opaque layer, the light resistance is improved, and deterioration during storage until the solar cell module is installed is reduced.

The thickness of the back surface protective layer is not particularly defined, but the mechanical strength tends to increase by increasing the thickness, and the flexibility tends to increase by decreasing the thickness. Therefore, in combination with the release layer, it is usually 10 μm or more, preferably 20 μm or more, more preferably 30 μm or more, and usually 1000 μm or less, preferably 500 μm or less, more preferably 100 μm or less.
However, as described above, when the film thickness of the light receiving side laminated portion in the solar cell module is large, it may be necessary to increase the thickness of the surface protective layer. However, since the release layer and the back surface protective layer are discarded during construction, it is not preferable in terms of cost to make the film thickness too large.

When a resin having a high Young's modulus is used in the light receiving side laminated portion of the solar cell module, it is preferable to increase the Young's modulus of the resin used for the back surface protective layer. By setting it as such an aspect, the curvature of the manufactured solar cell module can be prevented.
The appropriate Young's modulus of the back surface protective layer varies depending on the types of the weathering layer, the sealing layer, and the thin-film solar cell element, but is specifically preferably 100 MPa or more, more preferably 200 MPa or more, and still more preferably 400 MPa or more. Moreover, 3000 MPa or less is preferable, 2000 MPa or less is more preferable, and 1000 MPa or less is still more preferable.
Even when the Young's modulus of the resin used for the back surface protective layer is low, a resin having a high Young's modulus may be adopted as the resin used for the release layer. The degree of warpage can be adjusted by appropriately adjusting the thickness and / or Young's modulus of the release layer and the back surface protective layer.
Moreover, it is preferable that resin used for a back surface protective layer has a glass transition point that is equal to or higher than the thermal lamination temperature. This is because by using such a resin, it can be appropriately integrated with the release layer by thermal lamination.

  Hereinafter, although the solar cell module of this invention is demonstrated with reference to drawings, this invention is not necessarily limited only to such an embodiment.

FIG. 1 is a schematic view according to one embodiment of the solar cell module of the present invention. The solar cell module of the present invention includes a sealing layer 3, a thin-film solar cell element 4, a sealing layer 3, and a resin substrate 5 such as a polycarbonate resin or an acrylic resin, that is, on the sunlight 1 incident light side of the resin substrate 5. The weathering layer 2 is laminated in this order.
The solar cell module of the present invention is manufactured by thermally laminating these laminates at a temperature lower than the Tg of the resin substrate 5.

  The method of thermal laminating is not particularly limited as long as it is performed at a temperature lower than the Tg of the resin substrate 5, but portions other than the resin substrate 5 (an anti-glare layer 2, a sealing layer 3, and a thin film solar cell element 4, hereinafter the upper module) It is also preferable that the heat lamination is performed first for the part), and then the resin substrate 5 and the upper module part are heat laminated. By performing such a manufacturing method, the performance (particularly the fill factor) of the solar cell module can be improved. In addition, about the lamination | stacking of an upper module part, it is not necessary to thermally laminate at the temperature below Tg of a resin substrate.

  FIG. 2 is a schematic view according to a preferred embodiment of the present invention. In this solar cell module, a release layer 6 and a back surface protective layer 7 are laminated in this order on the side opposite to the incident light side of the resin substrate 5. By setting it as such an aspect, it can prevent that the back surface of the resin substrate 5 is damaged by the release layer 6 and the back surface protective layer 7. Further, with the resin substrate 5 as the center, the light receiving surface side laminated portion 8 including the sealing layer 3, the thin-film solar cell element 4, the sealing layer 3, and the weathering layer 2, the release layer 6 and the back surface protective layer 7 are included. Since it is divided into the back-side laminated portion 9, the shrinkage force of the resin due to cooling after heat lamination can be adjusted. Therefore, the curvature of a solar cell module can be prevented. Needless to say, layers not shown in FIGS. 1 and 2 can be appropriately provided depending on the application.

EXAMPLES Hereinafter, although the Example demonstrates the manufacturing method of the solar cell module of this invention further in detail, this invention is not limited only to the aspect of an Example.
In the examples, the fill factor, gelation rate, presence or absence of wrinkles, and warpage were evaluated by the following methods.
(Fill Factor)
Fill factor of the solar cell module was evaluated using a solar simulator manufactured by Celic.
(Evaluation of gelation rate)
A predetermined amount of toluene was put into an eggplant flask, and a sealing layer after heat lamination was put therein.
The eggplant flask was immersed in a water bath containing warm water heated to 60 ° C. and stirred for 4 hours. After stirring, the sealing layer component remaining in the eggplant flask was filtered and the weight was measured. From the measured weight, the fraction of the residual sealing layer component before and after the treatment was calculated and used as the gelation rate.
(Evaluation of wrinkles)
In the produced solar cell module, the power generation region and the presence or absence of wrinkles outside the power generation region were visually observed from the light receiving surface side, and evaluated according to the following criteria.
○: The maximum wrinkle length is less than 3 mm or no wrinkle exists.
Δ: The maximum wrinkle length is 3 mm or more and less than 10 mm, 3 or more and less than 10 mm wrinkles ×: The maximum wrinkle length is 10 mm or more and 10 mm or more wrinkles (3 or more warps) )
The solar cell module was placed on a flat plate with the weather resistant layer on top at room temperature, and the maximum value of the height difference between the center of the surface of the solar cell module and the four sides of the solar cell module was measured.

<Example 1>
The solar cell module shown in FIG. 1 was manufactured. In particular,
-Weatherproof layer: ETFE film with a thickness of 50 μm (50HK-DCS, manufactured by Asahi Glass Co., Ltd.)
Sealing layer: EVA film having a thickness of 300 μm (FIRST F806, 130 ° C. 45 minutes retention gelation rate: 75%)
・ Thin film solar cell element with a thickness of 50 μm (PEN with a thickness of 50 μm (Young's modulus at 25 ° C .: 1000 MPa) is used as a power generation element substrate and an amorphous silicon layer is deposited)
Sealing layer: EVA film having a thickness of 300 μm (FIRST F806, 130 ° C. 45 minutes retention gelation rate: 75%)
Sealing layer: ETFE film with a thickness of 50 μm (50HK-DCS, manufactured by Asahi Glass Co., Ltd.)
These are made into a laminated laminate, and an upper module is manufactured by using an NPC vacuum laminator and thermally laminating at 150 ° C. (vacuum degree: 80 Pa, vacuum time: 5 minutes, pressure: 100 kPa, heating and holding time: 15 minutes). (Preliminary laminating step).
next,
Upper module Sealing layer: 300 μm thick EVA film (FIRST F806, 130 ° C. 45 minutes retention gelation rate: 75%)
Resin substrate: 2 mm thick polycarbonate substrate (Mitsubishi Resin, Young's modulus at 25 ° C .: 2300 MPa, Tg: 137 ° C., 500 mm × 500 mm, 150 ° C., dried in 15 minutes)
These are superposed, and heat lamination is performed again at 130 ° C. using a vacuum laminator manufactured by NPC (degree of vacuum: 80 Pa, vacuum time: 5 minutes, pressure: 100 kPa, heating and holding time: 15 minutes)
Thus, a solar cell module 1 was produced.

<Example 2>
A solar cell module 2 was manufactured in the same manner as in Example 1 except that the holding time was 20 minutes in the second thermal lamination condition.

<Example 3>
The solar cell module 3 was manufactured in the same manner as in Example 1 except that the lamination temperature was 135 ° C. among the second thermal lamination conditions.

<Example 4>
The solar cell module 4 was manufactured in the same manner as in Example 3 except that the holding time was 20 minutes in the second thermal lamination condition.

<Comparative Example 1>
Solar cell module 5 was manufactured in the same manner as in Example 1 except that the lamination temperature was 150 ° C. and the holding time was 10 minutes among the second thermal lamination conditions.
Table 1 shows the results of measuring the gelation rate and fill factor of the sealing layer between the weather-resistant layer of the solar cell modules 1 to 5 and the thin-film solar cell, and the evaluation results of the presence or absence of wrinkles and warpage. As a result, when the lamination temperature exceeds 135 ° C., the fill factor is less than 50%, and the performance is remarkably deteriorated. Many large wrinkles of 10 mm or more were confirmed both in the power generation area and outside the power generation area.

<Example 5>
The solar cell module shown in FIG. 1 was manufactured. In particular,
-Weatherproof layer: ETFE film with a thickness of 50 μm (50HK-DCS, manufactured by Asahi Glass Co., Ltd.)
Sealing layer: EVA film having a thickness of 300 μm (FIRST F806, 130 ° C. 45 minutes retention gelation rate: 75%)
・ Thin film solar cell element with a thickness of 50 μm (PEN with a thickness of 50 μm (Young's modulus at 25 ° C .: 1000 MPa) is used as a power generation element substrate and an amorphous silicon layer is deposited)
Sealing layer: EVA film having a thickness of 300 μm (FIRST F806, 130 ° C. 45 minutes retention gelation rate: 75%)
Sealing layer: ETFE film with a thickness of 50 μm (50HK-DCS, manufactured by Asahi Glass Co., Ltd.)
Sealing layer: EVA film having a thickness of 300 μm (FIRST F806, 130 ° C. 45 minutes retention gelation rate: 75%)
Resin substrate: 2 mm thick polycarbonate substrate (Mitsubishi Resin, Young's modulus at 25 ° C .: 2300 MPa, Tg: 137 ° C., 500 mm × 500 mm, 150 ° C., dried in 15 minutes)
The solar cell module 6 was produced by superimposing these and using a vacuum laminator manufactured by NPC, and heat laminating at 130 ° C. (vacuum degree 80 Pa, vacuum time 5 minutes, pressurization time 5 minutes, holding 10 minutes). Table 1 shows the results of measuring the gelation rate and fill factor of the sealing layer between the weather resistant layer of the solar cell module 6 and the thin film solar cell, and the evaluation results of the presence or absence of wrinkles and warpage. When the solar cell module 6 was visually observed, there was a small wrinkle that was not a problem as a product.

<Comparative example 2>
A solar cell module 7 was produced in the same manner as in Example 5 except that the heat lamination temperature was 150 ° C.
Table 1 shows the results of measuring the gelation rate and fill factor of the sealing layer between the weather-resistant layer of the solar cell module 7 and the thin film solar cell, and the evaluation results of the presence or absence of wrinkles and warpage. When the solar cell module 7 was observed, many large wrinkles of 10 mm or more existed, and the problem of the design property as a product arose.

<Example 6>
The solar cell module shown in FIG. 1 was manufactured. In particular,
-Weatherproof layer: ETFE film with a thickness of 50 μm (50HK-DCS, manufactured by Asahi Glass Co., Ltd.)
Sealing layer: EVA film having a thickness of 300 μm (FHCE manufactured by CI Kasei Co., Ltd., 130 ° C. for 45 minutes, gelation rate: 75%)
・ Thin film solar cell element with a thickness of 50 μm (PEN with a thickness of 50 μm (Young's modulus at 25 ° C .: 1000 MPa) is used as a power generation element substrate and an amorphous silicon layer is deposited)
Sealing layer: EVA film having a thickness of 300 μm (FHCE manufactured by CI Kasei Co., Ltd., 130 ° C. for 45 minutes, gelation rate: 75%)
Resin substrate: 2 mm thick polycarbonate substrate (Mitsubishi Resin, Young's modulus at 25 ° C .: 2300 MPa, Tg: 137 ° C., 500 mm × 500 mm, 150 ° C., dried in 15 minutes)
The solar cell module 8 was produced by superimposing these and using a vacuum laminator manufactured by NPC, and heat laminating at 130 ° C. (vacuum degree 80 Pa, vacuum time 5 minutes, pressurization time 5 minutes, holding 10 minutes). The gelation rate of the sealing layer between the weather resistant layer and the thin film solar cell at this time was 58%.
When the solar cell module 8 was visually observed, there was a small wrinkle that was not a problem as a product. The fill factor at this time was 66%. Table 1 shows the results of measuring the gelation rate and fill factor of the sealing layer between the weather-resistant layer of the solar cell module 8 and the thin-film solar cell, the presence or absence of wrinkles, and the evaluation results of warpage.

<Example 7>
The solar cell module shown in FIG. 2 was manufactured.
Specifically, first,
Resin substrate: 2 mm thick polycarbonate substrate (Mitsubishi Resin, Young's modulus at 25 ° C .: 2300 MPa, Tg: 137 ° C., 500 mm × 500 mm, 150 ° C., dried in 15 minutes) 5 μm thick release layer (silicone System resin) and a back surface protective layer (PET) having a thickness of 50 μm.
Next, the following layers and weathering layers: ETFE film having a thickness of 50 μm (50HK-DCS, manufactured by Asahi Glass Co., Ltd.)
Sealing layer: EVA film having a thickness of 300 μm (low-temperature crosslinked EVA manufactured by CI Kasei Co., Ltd., 130 ° C. and 45 minutes retention gelation rate: 90%)
・ Thin film solar cell element with a thickness of 50 μm (PEN with a thickness of 50 μm (Young's modulus at 25 ° C .: 1000 MPa) is used as a power generation element substrate and an amorphous silicon layer is deposited)
Sealing layer: EVA film having a thickness of 300 μm (low-temperature crosslinked EVA manufactured by CI Kasei Co., Ltd., 130 ° C. and 45 minutes retention gelation rate: 90%)
・ A polycarbonate substrate having a thickness of 2 mm on which the release material and release film are laminated (a solar cell is laminated on the surface opposite to the surface on which the release film is laminated).
The solar cell module 9 was fabricated by superimposing these and using a vacuum laminator manufactured by NPC and thermally laminating at 125 ° C. (vacuum degree 80 Pa, vacuum time 5 minutes, pressurization time 5 minutes, holding 25 minutes). The gelation rate of the sealing layer between the weather resistant layer and the thin film solar cell at this time was 77%.
When the solar cell module 9 was visually observed, there was a small wrinkle that was not a problem as a product. The fill factor at this time was 66%.
Furthermore, the solar cell module 9 has no warpage, has extremely high flatness, and the back surface of the module is protected by a release film, so that a module that is not damaged in appearance is obtained. Table 1 shows the results of measuring the gelation rate and fill factor of the sealing layer between the weather-resistant layer of the solar cell module 9 and the thin-film solar cell, and the evaluation results of wrinkles and warpage.
By arranging the power generation portion and the protective film portion on different surfaces with respect to the thick resin substrate (polycarbonate), the flatness of the module can be easily maintained even in the heat laminating process.

<Comparative Example 3>
The solar cell module shown in FIG. 1 was manufactured. In particular,
-Weatherproof layer: ETFE film with a thickness of 50 μm (50HK-DCS, manufactured by Asahi Glass Co., Ltd.)
Sealing layer: EVA film having a thickness of 300 μm (FHCE manufactured by CI Kasei Co., Ltd., 130 ° C. for 45 minutes, gelation rate: 75%)
・ Thin film solar cell element with a thickness of 50 μm (PEN with a thickness of 50 μm (Young's modulus at 25 ° C .: 1000 MPa) is used as a power generation element substrate and an amorphous silicon layer is deposited)
Sealing layer: EVA film having a thickness of 300 μm (FHCE manufactured by CI Kasei Co., Ltd., 130 ° C. for 45 minutes, gelation rate: 75%)
Resin substrate: 2 mm thick polycarbonate substrate (Mitsubishi Resin, Young's modulus at 25 ° C .: 2300 MPa, Tg: 137 ° C., 500 mm × 500 mm, 150 ° C., dried in 15 minutes)
The solar cell module 10 was produced by superimposing them and using a vacuum laminator manufactured by NPC, and heat laminating at 130 ° C. (vacuum degree 80 Pa, vacuum time 5 minutes, pressurization time 5 minutes). The gelation rate of the stop layer between the weather resistant layer and the thin film solar cell at this time was 45%.
When the solar cell module 10 was visually observed, a large number of large wrinkles existed, resulting in a problem of design as a product. This is because the heating time (pressurization time and vacuum time) is short, and the sealing layer cannot be adapted to the power generation device substrate interface at the time of lamination and crosslinks. Since the heating time is short and the layer adjacent to the sealing layer (ETFE or power generation element) is not sufficiently heated, a difference in thermal expansion occurs between the sealing layer and the adjacent layer. It is the cause. In addition, when the gel fraction is low, the expansion and contraction of the sealing layer is severe under the condition of being exposed to an environment with a temperature difference of −40 ° C. to 85 ° C. for a long time. Damage to the cell.
Table 1 shows the results of measuring the gelation rate and fill factor of the sealing layer between the weather-resistant layer of the solar cell module 10 and the thin-film solar cell, the presence or absence of wrinkles, and the evaluation results of warpage.

DESCRIPTION OF SYMBOLS 1 Sunlight 2 Weatherproof layer 3 Sealing material 4 Thin film solar cell element 5 Resin substrate 6 Release layer 7 Back surface protective layer 8 Light-receiving surface side laminated part 9 Back surface side laminated part

Claims (11)

In the process of manufacturing a laminate having a resin substrate, a sealing layer, a thin-film solar cell element, a sealing layer, and a weather resistant layer in this order, a laminate process for thermally laminating the laminate is a method for manufacturing a solar cell module. And
The laminating step is performed at a temperature lower than the glass transition temperature (Tg) of the resin substrate so that the gelation rate of the sealing layer between the weather resistant layer and the thin film solar cell element is 50% or more. A method for producing a solar cell module, which is characterized.   The solar cell module manufacturing method according to claim 1, wherein the resin substrate has a Young's modulus at 25 ° C. of 500 MPa or more.   The method for manufacturing a solar cell module according to claim 1, wherein the resin substrate has a thickness of 100 μm or more.   The resin substrate includes one or more selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, nylon, polyethersulfone, polycarbonate, polyethylene, polypropylene, acrylic resin, urethane resin, or fluorine resin. The manufacturing method of the solar cell module of any one of -3.   The method for manufacturing a solar cell module according to claim 1, wherein the resin substrate is a polycarbonate resin or an acrylic resin.   The said lamination process is a manufacturing method of the solar cell module of any one of Claims 1-5 performed at temperature lower 5 degreeC or more than the glass transition temperature (Tg) of the said resin substrate.   The sun according to any one of claims 1 to 6, wherein the sealing layer is an ethylene-vinyl acetate copolymer (EVA) having a gelation rate of 70% or more when held at 130 ° C for 45 minutes. Manufacturing method of battery module. The said resin substrate is a manufacturing method of the solar cell module of any one of Claims 1-7 whose glass transition temperature (Tg) is 150 degrees C or less.   The method for producing a solar cell module according to claim 1, wherein the resin substrate has a glass transition temperature (Tg) of 140 ° C. or lower.   The manufacturing method of the solar cell module of any one of Claims 1-9 with which the said thin film solar cell element has an electric power generation layer containing an organic material.   The said laminated body manufacturing process laminates | stacks a back surface protective layer, a mold release layer, a resin substrate, a sealing layer, a thin film solar cell element, a sealing layer, and a weather resistant layer in this order. The manufacturing method of the solar cell module of description.