JP2018137409A - Thin film solar battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar battery module with high durability.SOLUTION: A thin film solar battery module comprises: a device substrate 3; a solar battery element 4; protection films 8 and 9; and a collecting wire 7 for taking out electricity generated in the solar battery element 4. Of the protection films 8 and 9, the vapor permeability is 1×10g/m/day or more and 1×10g/m/day or less under the environment at a 90%RH and 40°C.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thin film solar cell module.

  In recent years, solar cells using organic semiconductor polymers or perovskite semiconductor compounds have been actively studied. Especially, in order to improve the conversion efficiency of a solar cell, the example using PCBM as a material of the layer which comprises a solar cell element is reported. For example, Patent Documents 1 and 2 report examples in which PCBM is used as an n-type semiconductor material of an active layer as a bulk hetero type organic solar cell element.

JP 2012-111141 A JP 2009-90634 A

  Since organic semiconductor compounds or perovskite semiconductor compounds are generally considered to have a tendency to be weak against moisture, it is considered preferable to provide a thin-film solar cell module with a barrier layer having a low water vapor transmission rate. For example, Patent Document 1 describes using SiOx laminated on a PEN film by a sputtering method as a barrier layer. Patent Document 2 describes that a SiN and SiHN layer laminated on a PEN film by a plasma CVD method is used as a barrier layer. However, according to the study by the present inventors, it has been found that when the water vapor transmission rate of the barrier layer is too low, the conversion efficiency of the thin-film solar cell module tends to gradually decrease. An object of the present invention is to solve the above problems and provide a thin film solar cell module having high durability.

  The present inventors diligently studied to solve the above-mentioned problems, and as a result, by using a specific barrier layer, the above problems can be solved, and the present invention has been achieved.

That is, the gist of the present invention is as follows.
[1] A thin-film solar cell module having at least an element substrate, a solar cell element, and a protective film, wherein the protective film has a water vapor transmission rate of 1 × 10 ^{−4 in} a 40 ° C., 90% RH environment. A thin-film solar cell module characterized by being not less than g / m ² / day and not more than 1 × 10 ⁻³ g / m ² / day.
[2] The oxygen permeability of the protective film in an environment of 40 ° C. and 0% humidity is 1 × 10 ⁻³ cc / m ² / day / atm or more and 1 × 10 ⁻² cc / m ² / day / atm or less. The thin-film solar cell module according to [1], wherein
[3] The solar cell element has at least a pair of electrodes and an active layer between the pair of electrodes, and the active layer contains an organic semiconductor compound or a perovskite semiconductor compound. The thin film solar cell module according to [1] or [2].
[4] The solar cell element has an electron extraction layer between at least one electrode of the pair of electrodes and the active layer, and at least one of the active layer or the electron extraction layer is fullerene or a fullerene derivative. The thin film solar cell module according to any one of [1] to [3], wherein

  According to the present invention, an optical device having high durability can be provided.

It is a schematic cross section of a thin film solar cell module. It is a schematic cross section of a thin film solar cell module.

  Hereinafter, although an embodiment is described in detail about the present invention, the present invention is not limited to the following embodiment and is not limited to these contents, unless it deviates from the gist of the present invention.

<1. Thin-film solar cell module>
As shown in FIG. 1, the thin film solar cell module which concerns on one Embodiment of this invention has the protective film 8, the element board | substrate 3, the solar cell element 4, and the protective film 9 in this order. In addition, the solar cell element 4 is provided with a collector line 7 for taking out electricity generated by the solar cell element 4 to the outside. Hereafter, each structural layer which comprises a thin film solar cell module is demonstrated with reference to FIG.

<1-1. Protective film 8, 9>
The protective films 8 and 9 are composed of layers to which moisture proofing, oxygen permeation preventing property, light deterioration preventing property, impact resistance and the like are imparted, and may have a single layer structure or a laminated structure. It may be. In the present invention, the water vapor transmission rate of the protective films 8 and 9 under the environment of 40 ° C. and 90% RH is 1 × 10 ⁻⁴ g / m ² / day or more and 1 × 10 ⁻³ g / m ² / day or less. Thus, a thin film solar cell module having high durability can be provided.

  Usually, it is said that the solar cell element 3 provided with the active layer containing an organic semiconductor compound or a perovskite semiconductor compound tends to be weak against moisture and oxygen. Thus, it is considered that the solar cell element 3 is protected from water and oxygen by encapsulating the solar cell element with a protective film having a barrier performance, and the power generation performance can be maintained high. Considering this point, it is theoretically considered that the lower the water vapor transmission rate of the protective film, the better.

  However, according to the study by the present inventors, it has been surprisingly found that if the water vapor transmission rate of the protective film is too low, the durability of the thin film solar cell module may be lowered. The reason is not clear, but the following reasons are possible.

If oxygen remains in the sealing layer or barrier film constituting the protective film in the manufacturing stage of the thin film solar cell module, the active layer and the buffer layer of the solar cell element in the actual use environment of the thin film solar cell module The charge accumulation at the interface between or the buffer layer and the electrode becomes redundant. As a result, the electron mobility is reduced, and the power generation performance of the thin film solar cell module may be reduced. According to the study by the present inventors, this phenomenon tends to become prominent particularly when the active layer or the buffer layer contains fullerene or a fullerene derivative. However, it is considered that the problem of excessive charge accumulation as described above is that charge accumulation is mitigated by the presence of appropriate moisture, and as a result, the power generation performance of the thin-film solar cell module is restored. Therefore, in the present invention, the water vapor transmission rate of the protective film at 40 ° C. and 90% RH is 1 × 10 ⁻⁴ g / m ² / day or more and 1 × 10 ⁻³ g / m ² / day or less. As a result, while preventing a large amount of moisture from entering the thin-film solar cell module from the outside, it is possible to take in moderate moisture from the outside and recover the deterioration of the power generation performance due to the above-described oxygen degradation It is thought that it can be done. Therefore, it is considered that a thin film solar cell module having high durability can be provided.

Especially, it is more preferable that the water vapor permeability of the protective films 8 and 9 in a 40 ° C., 90% RH atmosphere is 2 × 10 ⁻⁴ g / m ² / day or more, and 3 × 10 ⁻⁴ g / m. ² / day or more is particularly preferable, while 9 × 10 ⁻⁴ g / m ² / day or less is more preferable, and 8 × 10 ⁻⁴ g / m ² / day or less is particularly preferable. .

  The water vapor transmission rate of the protective films 8 and 9 is measured in an environment of 40 ° C. and 90% RH by a measurement using an apparatus equipped with a humidity sensor, an infrared sensor and a gas chromatograph according to JIS K 7129, and by the cup method (JIS Z0208) be able to. In addition, when measuring not only the protective films 8 and 9 but the water-vapor-permeation rate of another layer, it can measure by the same method.

On the other hand, since oxygen tends to easily react with the active layer or buffer layer material, it is required to suppress oxygen penetration from the outside as much as possible for the purpose of preventing oxygen deterioration of the solar cell element. Therefore, the oxygen permeability of the protective films 8 and 9 in an environment of 40 ° C. and 0% humidity is preferably 1 × 10 ⁻¹ cc / m ² / day / atm or less, preferably 1 × 10 ⁻² cc / more preferably m is ² / day / atm or less, particularly preferably not more than ^{1 × 10 -3 cc / m 2} / day / atm. On the other hand, there is no particular lower limit.

  The oxygen permeability of the protective films 8 and 9 is an apparatus based on a differential pressure method according to JIS K 7126-1 or an infrared sensor based on an isobaric method according to JIS K 7126-2 and a device equipped with a gas chromatograph. Can be measured. In addition, when measuring the oxygen permeability of other layers as well as the protective films 8 and 9, it can be measured by the same method.

  As described above, the protective films 8 and 9 may have a single-layer structure or a laminated structure. When the protective films 8 and 9 have a laminated structure, the water vapor transmission rate and / or oxygen of each layer is used. The transmittance may be adjusted as appropriate so that the water vapor transmission rate and / or the oxygen transmission rate of the protective film are within the above range.

  Although there is no special restriction | limiting as a layer which comprises the protective films 8 and 9, For example, a sealing layer, a barrier film, a light-resistant layer, a hard-coat layer, a getter agent layer, an impact absorption layer etc. are mentioned. In the present invention, the protective film 8 includes all layers formed on the element substrate 3 side. Moreover, the protective film 9 shall contain all the layers other than the collector line 7 provided on the solar cell element 4. FIG. Hereinafter, with reference to FIG. 2, the example of the thin film solar cell module which comprised the protective films 8 and 9 with the sealing layer and the barrier film, respectively is demonstrated.

<1-1-1. Barrier film 1, 6>
The barrier films 1 and 6 are not particularly limited, but preferably have a structure in which a thin inorganic layer as a barrier agent layer is laminated on a resin base material.

  The material for forming the resin substrate is not particularly limited. For example, a polyolefin resin such as a homopolymer or copolymer such as ethylene, propylene, or butene; an amorphous polyolefin resin such as a cyclic polyolefin; polyethylene terephthalate ( PET), polyester resins such as polyethylene naphthalate (PEN); polyamide resins such as nylon 6, nylon 66, nylon 12, copolymer nylon; ethylene-vinyl acetate copolymer partial hydrolyzate (EVOH), polyimide Resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyether ether ketone resin, polycarbonate resin, polyvinyl butyral resin, polyarylate resin, fluororesin, acrylic resin, biodegradable resin Etc. Among these, from the viewpoint of heat resistance when forming the inorganic layer, a polyester resin is preferable, and polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is particularly preferable.

  The thickness of the resin substrate is not particularly limited, but is preferably 10 μm or more, more preferably 20 μm or more, and more preferably 30 μm or more in order to improve the mechanical strength of the organic solar cell element. On the other hand, it is preferably 500 μm or less, more preferably 400 μm or less, and particularly preferably 300 μm or less in order to prevent a decrease in flexibility of the thin film solar cell module.

  Note that the resin base material may be formed of a plurality of materials. Moreover, in order to improve a weather resistance, the resin base material may contain the well-known inorganic filler etc.

  The inorganic filler is not particularly limited. For example, silica, mica, talc, clay, bentonite, montmorillonite, kaolinite, wollastonite, calcium carbonate, titanium oxide, alumina, barium sulfate, potassium titanate, glass fiber Etc. Of these, talc is preferable. In addition, the inorganic filler mixed in the resin base material may be one type or two or more types.

  The inorganic material constituting the inorganic layer is silicon, aluminum, magnesium, zinc, tin, nickel, titanium, or oxides, carbides, nitrides, oxycarbides, oxynitrides, oxycarbonitrides, diamond-like carbons thereof. Or a mixture thereof or the like can be mentioned. Among these, in order to prevent current leakage when applied to a thin film solar cell module, the material constituting the inorganic layer is silicon oxide, silicon oxide carbide, silicon oxynitride, silicon oxycarbonitride, aluminum oxide, oxide Aluminum carbide, aluminum oxynitride, silicon nitride, aluminum nitride, diamond-like carbon and mixtures thereof are preferred. Among these, silicon oxide, silicon oxide carbide, silicon oxynitride, silicon oxycarbonitride, silicon nitride, aluminum oxide, aluminum oxycarbide, aluminum oxynitride, aluminum nitride, and these can be used to stably maintain high moisture resistance. The mixture of is particularly preferred. The inorganic layer may be composed of a plurality of inorganic materials. Moreover, you may have a some inorganic layer. Also in this case, the plurality of inorganic layers may be formed of the same material or may be formed of different materials. From the viewpoint of the design properties of the thin film solar cell module, the optical properties are preferably more transparent, and silicon oxide, silicon oxynitride, and silicon nitride are preferable.

  There is no special restriction | limiting as a formation method of an inorganic layer, What is necessary is just to form by arbitrary methods according to the material to be used. Specifically, any method such as a vapor deposition method and a coating method can be used. Among these, the vapor deposition method is preferable in that a uniform thin film having a high barrier property can be obtained. This vapor deposition method includes methods such as physical vapor deposition (PVD), chemical vapor deposition (CVD), and atomic layer deposition (ALD). Examples of physical vapor deposition include vacuum deposition, ion plating, and sputtering. Examples of chemical vapor deposition include plasma CVD using plasma, and a catalyst that thermally decomposes a material gas using a heated catalyst body. Examples include chemical vapor deposition (Cat-CVD).

  The thickness of the inorganic layer is preferably 10 nm or more, more preferably 20 nm or more, and particularly preferably 30 nm or more, in order to improve moisture-proof performance. , Preferably 1000 nm or less, more preferably 800 nm or less, and particularly preferably 600 nm or less.

If the water vapor transmission rate of the protective films 8 and 9 at 40 ° C. and 90% RH atmosphere can be 1 × 10 ⁻⁴ g / m ² / day or more and 1 × 10 ⁻³ g / m ² / day or less, Although there is no special restriction | limiting in the water vapor transmission rate of the barrier films 1 and 6, Usually, since the water vapor transmission rate of the protective films 8 and 9 is dependent on the water vapor transmission rate of a barrier film, it is 40 degreeC of the barrier films 1 and 6. The water vapor transmission rate in a 90% RH atmosphere is preferably 1 × 10 ⁻⁴ g / m ² / day or more, more preferably 3 × 10 ⁻⁴ g / m ² / day or more. It is particularly preferably 10 ⁻⁴ g / m ² / day or more, while it is preferably 1 × 10 ⁻³ g / m ² / day or less, and 8 × 10 ⁻⁴ g / m ² / day or less. more preferably ^{in, 6 × 10 -4 g / m} 2 It is particularly preferable day or less.

  The water vapor transmission rate of the barrier film can be adjusted by a known method, for example, a method of increasing the film thickness of the inorganic layer, a method of forming a multilayer structure of an inorganic layer and an organic layer, a resin substrate and an inorganic layer Among them, there are a method of introducing an anchor coat layer, a method of adding an inorganic filler to a resin substrate, a method of adding a moisture getter material to a resin substrate, and the like.

When the oxygen permeability of the protective films 8 and 9 in an environment of 40 ° C. and 0% humidity is 1 × 10 ⁻¹ cc / m ² / day / atm or less, other layers constituting the protective films 8 and 9 The oxygen permeability may be adjusted in consideration of the oxygen permeability, but the oxygen permeability of the protective films 8 and 9 usually tends to depend on the barrier film. Therefore, the oxygen permeability of the barrier films 1 and 6 in an environment of 40 ° C. and 0% humidity is preferably 1 × 10 ⁻¹ cc / m ² / day / atm or less, preferably 1 × 10 ⁻² cc / more preferably m is ² / day / atm or less, particularly preferably not more than ^{1 × 10 -3 cc / m 2} / day / atm. On the other hand, there is no particular lower limit.

  The oxygen permeability of the barrier film can be adjusted by a known method, for example, a method of increasing the thickness of the inorganic layer, a method of forming a multilayer structure of an inorganic layer and an organic layer, a resin base material and an inorganic layer And the like, a method of introducing an anchor coat layer between them, a method of adding an inorganic filler to a resin substrate, a method of adding an oxygen scavenger to a resin substrate, and the like.

<1-1-2. Sealing layer 2, 5>
The sealing layers 2 and 5 are layers provided to improve the adhesion between the solar cell element 4 and the barrier layers 1 and 6, respectively.

  The material for forming the sealing layers 2 and 5 is not particularly limited. For example, polystyrene (PS) resin, polyvinyl chloride (PVC) resin, polyvinyl butyral (PVB) resin, polyisobutylene (PIB) resin, polyimide resin, for example. (PI), acrylonitrile-butadiene-styrene copolymer (ABS) resin, polymethyl methacrylate (PMMA) resin, polyurethane (PU) resin, epoxy resin, acrylic adhesive, ethylene-vinyl acetate copolymer (EVA) resin , Polyethylene (PE) resin, polypropylene (PP) resin, polyoxymethylene (POM) resin, polyethylene terephthalate (PET) resin, polyethylene naphthalate (PEN) resin, modified polyethylene resin modified with maleic acid or silane, etc. Polypropylene resin or poly De (PA) resins.

  Each of the sealing layers 2 and 5 may be formed of one type of material or may be formed of two or more types of materials. Moreover, the sealing layers 2 and 5 may each be a single layer or may have a laminated structure of two or more layers. In the case of a laminated structure, the material forming the sealing layer may be the same or different. Moreover, the sealing layers 2 and 5 may have an inorganic filler or the like.

  In addition, when a thin film solar cell module is constructed or when bending occurs, a T-shaped peel test between the sealing layers 2 and 5 and the element substrate 1 is performed to prevent peeling inside the thin film solar cell module. The measured interlayer adhesion strength is preferably 5 N / 25 mm or more, more preferably 10 N / 25 mm or more. On the other hand, there is no upper limit.

The sealing layers 2 and 5 preferably have high bending strength from the viewpoint of maintaining strength of the thin-film solar cell module. Although it is also related to the strength of the layers other than the sealing material and is difficult to define in general, the entire thin-film solar cell module has good bending workability and has bending strength that does not cause peeling of the bent portion. Is desirable. Specifically, the bending strength at 25 ° C. of the sealing layers 2 and 5 is 1.0 × 10 ⁵ Pa or more and 1.0 × 10 6 from the viewpoint of alleviating the stress generated in the thin film solar cell module during construction. ⁷ Pa or less is preferable.

  In addition, the sealing layers 2 and 5 preferably have a higher longitudinal elastic modulus at 25 ° C. from the viewpoint of relaxing external stress applied to the thin film solar cell module when the thin film solar cell module is applied. This is an important practical performance particularly in a film-type thin film solar cell module. As a method for measuring the longitudinal elastic modulus, the sealing layer is melted and then processed into a test piece (including curing treatment when curing is required), and the obtained test piece is measured with a conventionally known tensile tester. The stress-strain curve is obtained from the proportional constant of stress and strain in the coaxial direction in the elastic range where Hooke's law is established.

The longitudinal elastic modulus at 25 ° C. of the sealing layers 2 and 5 is 1.0 × 10 ⁸ Pa or more, preferably 5.0 × 10 ⁸ Pa or more, more preferably 1.0 × 10 ⁹ Pa or more. When the longitudinal elastic modulus is in this range, it can be applied with minimal damage to the thin film solar cell module, and the finished thin film solar cell module has good design. Furthermore, since the stiffness as a thin film solar cell module can be imparted, the thin film solar cell module can be folded and wrinkled at the time of construction and processing, and the handling property when handling the thin film solar cell module can be improved.

  Furthermore, since the thin film solar cell module is often heated by receiving light, it is preferable that the sealing layers 2 and 5 also have heat resistance. From this viewpoint, the melting point of the material forming the sealing layers 2 and 5 is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 130 ° C. or higher, and usually 350 ° C. or lower, preferably 320 ° C. or lower. More preferably, it is 300 ° C. or lower. By increasing the melting point, it is possible to prevent the sealing material from melting and deteriorating when the thin film solar cell module is used.

  The film thickness of the sealing layers 2 and 5 is not particularly limited, but is 10 μm or more in order to prevent the organic thin film solar cell element from being damaged by external pressure or impact from the surface layer side of the thin film solar cell module. It is preferably 20 μm or more, more preferably 30 μm or more. On the other hand, in order to prevent the visible light transmittance from being significantly reduced, it is preferably 100 μm or less, and 75 μm or less. Is more preferable, and 60 μm or less is particularly preferable.

  The sealing layers 2 and 5 may be provided with functions such as ultraviolet blocking, heat ray blocking, conductivity, antireflection, antiglare, light diffusion, light scattering, wavelength conversion, and gas barrier properties. In particular, the organic thin film solar cell element tends to be deteriorated by water or oxygen, and may be deteriorated by ultraviolet rays of sunlight. Therefore, it is preferable to have a gas barrier property and an ultraviolet blocking function. As a method for imparting such a function, a layer having a function may be laminated on the sealing layers 2 and 5 by coating film formation, or a material having such a function may be dissolved and dispersed. And may be contained in the sealing layers 2 and 5.

As long as the protective films 8 and 9 have the water vapor transmission rate as described above, the water vapor transmission rate at 100 μm of the sealing layers 2 and 5 is not particularly limited. It is preferably 10 ⁻² g / m ² / day or more, preferably 10 ⁻¹ g / m ² / day or more in an environment of 40 ° C. and 90% RH so that it can be sufficiently supplied to the battery element side. . In order to prevent moisture from entering the solar cell element from the end portion of the thin-film solar cell module, 40 ° C., preferably not more than 20g / m ² / day under 90% RH environment, preferably 10 g / m ² / Day or less, more preferably 5 g / m ² / day or less.

In addition, when the protective films 8 and 9 have the above-described oxygen permeability, as described above, the oxygen permeability of the protective films 8 and 9 tends to depend on the oxygen permeability of the barrier films 1 and 6. However, it is not always necessary to set the oxygen permeability of the sealing layer low. However, in order to suppress oxygen from entering the thin film solar cell module from the outside as much as possible, the oxygen permeability of the sealing layers 2 and 5 is 1 × 10 ² cc in an ambient atmosphere of 40 ° C. and 0% humidity. / M ² / day / atm or less, preferably 1 × 10 ¹ cc / m ² / day / atm or less, more preferably 1 cc / m ² / day / atm or less. There is an advantage that deterioration due to oxidation of the thin film solar cell element can be suppressed as much as oxygen does not permeate.

  In addition, as above-mentioned, the structure of the protective films 8 and 9 is not limited to the structure of FIG. 2, The other layer may be included. For example, you may have a hard-coat layer, a getter agent layer, a light-resistant layer, a shock absorption layer, etc.

  The hard coat layer is a layer that can impart chemical resistance, scratch resistance and surface smoothness to the thin-film solar cell module.

  The hard coat layer can be formed of a known material, for example, an ultraviolet curable resin; an electron beam curable resin; an alkoxysilane hydrolytic condensation resin; a melamine resin; a (meth) acrylate alcohol-modified polyfunctional compound; It can be formed using acrylic resins such as methylolpropane (meth) acrylate, tripropylene glycol diacrylate, pentaerythritol triacrylate, 1,6 hexanediol (meth) acrylate. The hard coat layer preferably contains silica particles and a matting agent in addition to the above materials.

  The average primary particle diameter of the silica particles is not particularly limited, but is preferably 0.0005 μm or more, more preferably 0.001 μm or more, and preferably 0.1 μm or less. More preferably, it is not more than 01 μm.

  The hardness of the hard coat layer is preferably 2H or higher in pencil hardness, and more preferably 3H or higher.

  The film thickness of the hard coat layer is preferably 1 μm or more in order to improve the scratch resistance, more preferably 2 μm or more, while it is 10 μm or less in order to suppress the curing shrinkage of the hard coat layer. Preferably, it is 8 μm or less.

  Moreover, the transparency of the thin-film solar cell module is controlled by setting the arithmetic average roughness (Ra) defined in JIS B0601 (1994) on the opposite side of the surface protective film coated with the hard coat layer to an appropriate range. can do.

  When the arithmetic average roughness (Ra) is less than 0.01 μm, the generation of Newton rings cannot be sufficiently suppressed. On the other hand, if the (Ra) exceeds 0.05 μm, the glare increases and the visibility decreases. The (Ra) is preferably 0.01 to 0.05 μm from the viewpoint of further suppressing the generation and glare of Newton rings and increasing the permeability. The arithmetic average roughness (Ra) can be obtained by using SE-3400 manufactured by Kosaka Laboratory Ltd.

  The getter agent layer is a layer that absorbs moisture and / or oxygen. Some components of the solar cell element are deteriorated by moisture as described above, and some are deteriorated by oxygen. Therefore, by covering the solar cell element with the getter agent layer, it is possible to protect the solar cell element and the like from moisture and / or oxygen and to maintain high power generation performance.

  Here, unlike the barrier film as described above, the getter agent layer does not prevent moisture permeation but absorbs moisture. When a solar cell element is covered with a barrier film or the like by using a layer that absorbs moisture, the getter layer captures moisture that slightly enters the space formed between the barrier films, and the solar cell element due to moisture Can be eliminated.

The degree of water absorption capacity of the getter agent layer is usually 0.1 mg / cm ² or more, preferably 0.5 mg / cm ² or more, more preferably 1 mg / cm ² or more. The higher the numerical value, the higher the water absorption capacity, and the deterioration of the solar cell element can be suppressed. Moreover, although there is no restriction | limiting in an upper limit, it is usually 10 mg / cm < ² > or less. In addition, when the solar cell element is covered with a barrier film or the like because the getter agent layer absorbs oxygen, the getter agent layer captures oxygen that slightly enters the space formed by the barrier film and the solar The influence on the battery element can be eliminated.

  Further, since the thin film solar cell module is often heated by receiving light, it is preferable that the getter agent layer also has heat resistance. From this viewpoint, the melting point of the constituent material of the getter agent layer is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 130 ° C. or higher, and usually 350 ° C. or lower, preferably 320 ° C. or lower, more preferably. It is 300 degrees C or less. By increasing the melting point, it is possible to reduce the possibility that the getter agent layer melts and deteriorates when the thin film solar cell module is used.

  The thickness of the getter agent layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, more preferably 15 μm or more, and usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility.

  The getter agent layer can be formed by any method depending on the type of the water-absorbing agent or desiccant. For example, a method of attaching a film in which the water-absorbing agent or desiccant is dispersed with an adhesive, A method of applying the solution by a spin coating method, an ink jet method, a dispenser method, or the like can be used. Further, a film forming method such as a vacuum evaporation method or a sputtering method may be used.

  As a film for a water absorbing agent or a desiccant, for example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, fluorine resin, poly (meth) acrylic resin, polycarbonate resin, or the like can be used. Among these, a film of polyethylene resin, fluorine resin, cyclic polyolefin resin or polycarbonate resin is preferable. In addition, the said resin may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The light-resistant layer is a layer containing an organic ultraviolet absorber and has a function of cutting ultraviolet rays. As the organic ultraviolet absorber, for example, benzophenone-based, benzotriazole-based, triazine-based, benzoxazinone-based, salicylate-based, cyanoacrylate-based, salicylate-based, and acrylonitrile-based organic ultraviolet absorbers can be used. Of these, benzosophenone-based, benzotriazole-based, and benzoxazinone-based organic ultraviolet absorbers can be particularly preferably used because they have a high ultraviolet absorptivity and easy wavelength control.

  The shock absorbing layer is a layer that relieves physical pressure from the outside, and is a layer that plays a role as an adhesive paste layer when installing the thin film solar cell module.

  The thickness of the adhesive layer is not particularly limited, but is preferably 10 μm or more, more preferably 20 μm or more, for relaxation of physical impact, while the solar cell element emits a lot of light. In order to receive light, the thickness is preferably 200 μm or less, and more preferably 150 μm or less.

  The material for forming the adhesive layer is not particularly limited, and examples thereof include acrylic adhesives, polyester adhesives, rubber adhesives, silicone adhesives, and polyurethane adhesives. Especially, an acrylic adhesive material is preferable from a viewpoint of a weather resistance and transparency.

  In addition, when a protective film is formed including the above layers, the water vapor transmission rate of each layer is appropriately set so that the water vapor transmission rates of the protective films 8 and 9 are in the above range. Adjust it. However, since the water vapor transmission rate of the protective films 8 and 9 tends to depend on the water vapor transmission rate of the barrier films 1 and 6 as described above, the protective film 8 is mainly the water vapor transmission rate of the barrier films 1 and 6. , 9 is preferably adjusted. The same applies to the oxygen transmission rate.

<1-2. Element substrate 3>
The element substrate 3 is a support member that supports the solar cell element 4. In the present invention, the element substrate 3 is not particularly limited, but when the barrier layer 1 side is the light receiving surface of the thin film solar cell module, the element substrate 3 has a visible light transmittance of 60% or more. Preferably, it is 70% or more, more preferably 80% or more.

  The element substrate 3 is not particularly limited, and examples thereof include a glass substrate, a resin base material, or a metal base material provided with insulation. In particular, the element substrate is preferably a resin base material from the viewpoint of reducing the weight of the thin film solar cell module and increasing the degree of freedom of installation of the thin film solar cell module.

  The resin base material is not particularly limited, but polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, fluororesin film, polyvinyl chloride, Organic materials such as polyethylene, polypropylene, cyclic polyolefin, cellulose, acetylcellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, poly (meth) acrylic resin, phenol resin, epoxy resin, polyarylate, polynorbornene, etc. It is done. Among these, polyethylene terephthalate, polyethylene naphthalate, polyimide, and poly (meth) acrylic resin are preferable from the viewpoint of easy formation of the solar cell element 3, and in particular, as described above, the peripheral region of the thin film solar cell module is melted. In this case, the material of the element substrate 4 is preferably polyethylene terephthalate or polyethylene naphthalate.

  The thickness of the element substrate 3 is not particularly limited, but is preferably 10 μm or more, more preferably 20 μm or more, in order to improve the resistance to tension and heating when manufacturing a solar cell element, On the other hand, when it is set as a flexible thin film solar cell module, when the thickness of the element substrate 3 is too large, the flexibility of the thin film solar cell module is lowered, so that it is 500 μm or less. Preferably, it is 400 μm or less, and particularly preferably 300 μm or less.

<1-3. Solar Cell Element 4>
The solar cell element 4 includes at least a pair of electrodes and an active layer between the pair of electrodes. Further, a buffer layer may be provided between the electrodes of the active layer.

  The problem of deterioration of the solar cell element due to oxygen remaining in the thin film solar cell module is particularly noticeable when at least one of the active layer and the buffer layer is formed containing a fullerene or a fullerene derivative as described above. Can be. Therefore, the present invention is more effective when at least one of the active layer and the buffer layer contains fullerene or a fullerene derivative, and particularly when at least one of the active layer and the electron extraction layer contains fullerene or a fullerene derivative. Can be effective.

<1-3-1. Pair of electrodes>
The pair of electrodes includes a lower electrode and an upper electrode, and one of the pair of electrodes is an electrode having a function of collecting holes generated by the active layer absorbing light (hereinafter referred to as an anode). The other electrode is an electrode having a function of collecting electrons generated when the active layer absorbs light (hereinafter referred to as a cathode). When the lower electrode is an anode, the upper electrode is preferably a cathode, and when the lower electrode is a cathode, the upper electrode is preferably an anode.

  In addition, if one electrode is a transparent electrode among a pair of electrodes, the other electrode may be a transparent electrode or a non-transparent electrode. However, when the thin film solar cell module is a transmissive thin film solar cell module, that is, a so-called see-through thin film solar cell module, the pair of electrodes are preferably transparent electrodes. In the present invention, the transparent electrode usually means an electrode having a visible light transmittance of 60% or more. In order to improve the conversion efficiency, the transparent electrode has a visible light transmittance of 70% or more. Preferably, it is 80% or more. On the other hand, the upper limit is not particularly limited, but is usually 90% or less. The visible light transmittance of the electrode can be measured by a method similar to the method for measuring the visible light transmittance of the element substrate 4 described above.

  The transparent electrode may be formed of a single transparent conductive layer, or may be formed by laminating a transparent conductive layer and a metal layer. For example, the transparent conductive layer, the metal thin layer, and the transparent conductive layer may be A laminated structure formed sequentially may be used.

The material used for the transparent electrode layer is not particularly limited, but includes tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), tungsten-doped indium oxide (IWO), Examples thereof include oxides of zinc and aluminum (AZO), indium oxide (In ₂ O ₃ ), and the like. Among these, it is preferable to use amorphous oxides such as tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), and tungsten-doped indium oxide (IWO).

  When the transparent electrode has a laminated structure of a transparent conductive layer and a metal layer, the material of the metal layer is not particularly limited. For example, gold, platinum, silver, aluminum, nickel, titanium, magnesium, calcium, barium, sodium , Chromium, copper, cobalt and the like, or alloys thereof. Among these, it is preferable that the material forming the metal layer is silver or a silver alloy having high electric conductivity and high visible light transmittance in the thin film. In addition, as an alloy of silver, in order to improve the stability as a thin film which is not easily affected by sulfidation or chlorination, an alloy of silver and gold, an alloy of silver and copper, an alloy of silver and palladium, an alloy of silver and copper An alloy of palladium, an alloy of silver and platinum, and the like can be given.

  The thickness of the metal layer is not particularly limited as long as the transparent electrode can maintain a visible light transmittance of 70% or more, preferably 1 nm or more, more preferably 5 nm or more, while 15 nm. Or less, more preferably 10 nm or less. The reason for this is that if the metal layer is too thin, it may be difficult to obtain high conductivity. If the metal layer is too thick, the light transmittance is reduced and the amount of light incident on the organic solar cell element is reduced. This is because the conversion efficiency decreases.

  When the non-transparent electrode is used, there is no particular limitation. For example, the non-transparent electrode can be formed by forming the metal layer as described above with a thick film.

  The thicknesses of the lower electrode and the upper electrode are not particularly limited and may be arbitrarily selected in consideration of optical characteristics and electrical characteristics. Among them, in order to suppress the sheet resistance, the thickness of each of the lower electrode and the upper electrode is preferably 10 nm or more, more preferably 20 nm or more, further preferably 50 nm or more, In order to maintain a high transmittance, the thickness is preferably 10 μm or less, more preferably 1 μm or less, and even more preferably 500 nm or less.

  When the lower electrode is an anode and the upper electrode is a cathode, it is preferable to use a material having a work function larger than that of the upper electrode. On the other hand, when the lower electrode is a cathode and the upper electrode is an anode, the lower electrode is preferably formed of a material having a work function smaller than that of the upper electrode. In addition, by providing the organic solar cell element with a lower buffer layer and / or an upper buffer layer, which will be described later, and adjusting the work function, the lower electrode and the upper electrode can be formed of a material having the same work function. .

  The formation method of the lower electrode and the upper electrode is not particularly limited, and can be formed by a known method according to the material to be used. For example, a vacuum film forming method such as an evaporation method or a sputtering method, or a wet film forming method in which an ink containing nanoparticles or a precursor is applied to form a film.

<1-3-2. Active layer>
The material for forming the active layer is not particularly limited, but the present invention is particularly effective in the case of an active layer containing an organic semiconductor compound or a perovskite semiconductor compound that easily deteriorates with respect to water or oxygen.

  The structure of the active layer is not particularly limited, but is a thin film stack type in which a layer containing a p-type organic semiconductor compound and a layer containing an n-type semiconductor compound are stacked, and a p-type organic semiconductor compound Examples thereof include a bulk hetero-junction type which is a layer (mixed layer) in which n-type semiconductor compounds are mixed, or a layer containing a perovskite semiconductor compound. Note that the bulk heterojunction type active layer or the active layer containing the perovskite semiconductor compound has a structure in which a layer containing a p-type semiconductor compound and / or a layer containing an n-type semiconductor compound is further laminated. May be.

  The p-type organic semiconductor compound is not particularly limited, and examples thereof include a p-type low-molecular organic semiconductor compound, a p-type organic semiconductor oligomer, and a p-type organic semiconductor polymer.

  The p-type low-molecular organic semiconductor compound is not particularly limited, but a porphyrin compound such as tetrabenzoporphyrin, tetrabenzocopper porphyrin, tetrabenzozinc porphyrin; phthalocyanine compound such as phthalocyanine, copper phthalocyanine, zinc phthalocyanine; naphthalocyanine compound; tetracene And pentacene polyacene.

  The p-type organic semiconductor oligomer is not particularly limited, and examples thereof include oligothiophenes such as sexithiophene or derivatives containing these compounds as a skeleton.

  The p-type organic semiconductor polymer is not particularly limited. Examples thereof include polythiophene containing poly (3-alkylthiophene) and the like, polyfluorene, polyphenylene vinylene, polytriallylamine, polyacetylene, polyaniline, polypyrrole, a polymer containing a thiophene ring or a thiophene condensed ring. More specifically, known p-type semiconductor polymers such as those described in International Publication No. 2011/016430, International Publication No. 2013/180243, Japanese Unexamined Patent Publication No. 2012-191194, and the like can be mentioned.

The n-type semiconductor compound is not particularly limited. For example, a fullerene; a fullerene derivative; a quinolinol derivative metal complex represented by 8-hydroxyquinoline aluminum; a condensed ring such as naphthalenetetracarboxylic acid diimide or perylenetetracarboxylic acid diimide Tetracarboxylic acid diimides; perylene diimide derivatives, terpyridine metal complexes, tropolone metal complexes, flavonol metal complexes, perinone derivatives, benzimidazole derivatives, benzoxazole derivatives, thiazole derivatives, benzthiazole derivatives, benzothiadiazole derivatives, oxadiazole derivatives, thiadiazoles Derivatives, triazole derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxaline derivatives, benzoquino Derivatives, bipyridine derivatives, borane derivatives; total fluorides of condensed polycyclic aromatic hydrocarbons such as anthracene, pyrene, naphthacene or pentacene; single-walled carbon nanotubes, n-type polymers (n-type polymer semiconductor materials), etc. . Among these, fullerene or fullerene derivatives are particularly preferable. The fullerene derivatives are not particularly limited, but include methanofullerene derivatives, plateau fullerene derivatives, Diels Alder fullerene derivatives, diazoline fullerene derivatives, bingel fullerene derivatives, ketolactam fullerene derivatives, and azafulleroid fullerene derivatives. It is done. Specific examples of these structures include those described in publicly known documents such as International Publication No. 2011-016430, Japanese Unexamined Patent Publication No. 2012-191194, or Japanese Unexamined Patent Publication No. 2011-504168. Two or more fullerene derivatives may be used. Among them, fullerene derivatives are [6,6] -phenyl-C ₆₁ -butyric acid methyl ester ([60] PCBM), [6,6] -phenyl-C ₇₁ -butyric acid methyl ester ([70] PCBM), or A mixture thereof is preferred.

  The perovskite semiconductor compound is not particularly limited, but is preferably a compound represented by the following formula (1).

_An MX _{(n + 2)} (1)

  In formula (1), n represents an integer of 1 or 2.

  In formula (1), A represents a monovalent organic molecule.

The monovalent organic molecule is not particularly limited, but for example, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, dimethylamine, dimethylamine, dipropylaminedibutylamine, dipentylamine, dihexylamine, trimethylamine , Triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, ethylmethylamine, methylpropylamine, butylmethylamine, methylpentylamine, hexylmethylamine, ethylpropylamine, ethylbutylamine, imidazole, azole, pyrrole , Aziridine, azirine, azetidine, azeto, azole, imidazoline, carbazole and their ions (eg, methylammonium (CH ₃ NH ₃ ) etc.) and phenethylammonium. Of these, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine and their ions and phenethylammonium are preferred, and methylamine, ethylamine, propylamine and these ions are more preferred.

  In formula (1), M represents a divalent metal atom. Divalent metal atoms are not particularly limited, but lead, tin, zinc, titanium, antimony, bismuth, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium , Molybdenum, europium, and the like. These elements may be used independently and 2 or more types may be used together.

  In formula (1), X represents a halogen atom or a chalcogen atom. The halogen atom is not particularly limited, and examples thereof include chlorine, bromine, iodine, and sulfur. The chalcogen atom is not particularly limited, but selenium can be mentioned. These may be used independently and 2 or more types may be used together.

  Specific examples of the perovskite semiconductor compound include perovskite semiconductor compounds described in, for example, International Publication No. 2014/045021, Japanese Unexamined Patent Publication No. 2014-49596, Japanese Unexamined Patent Publication No. 2006-82003, and the like. .

Further, when the active layer is formed of a perovskite semiconductor compound, a porous film such as TiO ₂ or Al ₂ O ₃ may be formed under the layer containing the compound.

  The film thickness of the active layer is not particularly limited, but is usually 50 nm or more, preferably 100 nm or more, and is usually 1000 nm or less, preferably 500 nm or less. It is preferable that the thickness of the active layer is 50 nm or more because the uniformity of the film is maintained and short-circuiting is less likely to occur. Moreover, it is preferable that the thickness of the active layer is 1000 nm or less from the viewpoint that the internal resistance is small and that the diffusion of charges is good without being too far apart from each other.

  The method for forming the active layer is not particularly limited, and can be formed by a known method in consideration of the material to be used. Specifically, it can be formed by a vacuum film-forming method such as an evaporation method or a sputtering method, or a wet film-forming method using a compound that forms the active layer or a precursor compound thereof, and an ink containing a solvent.

  As a wet film forming method, there is no particular limitation, spin coating method, reverse roll coating method, gravure coating method, kiss coating method, roll brush method, spray coating method, air knife coating method, wire barber coating method, pipe doctor method, Examples of the method include impregnation / coating and curtain coating.

  The solvent is not particularly limited, but for example, aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane, tetralin or decane; aroma such as toluene, xylene, mesitylene, cyclohexylbenzene, chlorobenzene or orthodichlorobenzene Aromatic hydrocarbons such as cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetralin or decalin; lower alcohols such as methanol, ethanol or propanol; acetone, methyl ethyl ketone, cyclopentanone or Aliphatic ketones such as cyclohexanone; aromatic ketones such as acetophenone or propiophenone; esters such as ethyl acetate, butyl acetate or methyl lactate; Arm, methylene chloride, dichloroethane, halogenated hydrocarbons such as trichloroethane or trichlorethylene; ethers such as ethyl ether and tetrahydrofuran or dioxane; or an amide such as dimethylformamide or dimethylacetamide, and the like. In addition, a solvent may use 1 type of solvent independently, and may use arbitrary 2 or more types of solvents together by arbitrary ratios.

  When the active layer is a thin film laminated type of a layer containing a p-type organic semiconductor compound and a layer containing an n-type semiconductor compound, there is no particular limitation, but by forming each layer by the method described above What is necessary is just to form. When the active layer is a bulk heterojunction type, there is no particular limitation, but an ink containing a p-type organic semiconductor compound, an n-type semiconductor compound, and a solvent is prepared, and the ink is used. It is preferably formed by a wet film formation method.

  In addition, when the active layer is formed of a perovskite semiconductor compound, the method for forming the active layer is not particularly limited, but International Publication No. 2014/045021, Japanese Unexamined Patent Publication No. 2014-49596, Japanese Unexamined Patent Publication No. 2006-2006. The active layer can be formed by applying a coating solution as a precursor as described in Japanese Patent No. 82003.

<1-3-3. Buffer layer>
The buffer layer is classified into an electron extraction layer that improves the efficiency of extracting electrons from the active layer to the cathode or a hole extraction layer that improves the efficiency of extracting holes from the active layer to the anode. When the lower electrode is an anode and the upper electrode is a cathode, the lower buffer layer may be a hole extraction layer and the upper buffer layer may be an electron extraction layer. On the other hand, when the lower electrode is a cathode and the upper electrode is an anode, the lower buffer layer may be an electron extraction layer and the upper buffer layer may be a hole extraction layer.

  The material of the electron extraction layer is not particularly limited as long as it can improve the efficiency of electron extraction from the active layer to the cathode, and includes an inorganic compound or an organic compound.

  Examples of inorganic compounds include salts of alkali metals such as Li, Na, K or Cs; n-type semiconductor oxides such as titanium oxide (TiOx) and zinc oxide (ZnO). Among them, the alkali metal salt is preferably a fluoride salt such as LiF, NaF, KF or CsF, and the n-type semiconductor oxide is preferably zinc oxide (ZnO). Although the operation mechanism of such a material is unknown, it is conceivable to reduce the work function of the cathode when combined with a cathode made of Al or the like and increase the voltage applied to the solar cell element.

Examples of organic compounds include phosphine compounds having a double bond between a phosphorus atom and a group 16 element such as triarylphosphine oxide compounds; substituents such as bathocuproin (BCP) or bathophenanthrene (Bphen) A phenanthrene compound in which the 1-position and the 10-position may be substituted with heteroatoms; a boron compound such as triarylboron; an organic such as (8-hydroxyquinolinato) aluminum (Alq ₃ ) Metal oxide; Compound having 1 or 2 ring structure which may have a substituent such as oxadiazole compound or benzimidazole compound; naphthalenetetracarboxylic anhydride (NTCDA) or perylenetetracarboxylic anhydride Product (PTCDA), such as dicarboxylic acid anhydride Aromatic compounds having a slip dicarboxylic acid structure.

Moreover, fullerene or a fullerene derivative can also be used as an electron extraction layer. In particular, when a perovskite semiconductor compound is used, it is preferable to use fullerene or a fullerene derivative as the electron extraction layer. The fullerene derivatives are not particularly limited, but include methanofullerene derivatives, plateau fullerene derivatives, Diels Alder fullerene derivatives, diazoline fullerene derivatives, bingel fullerene derivatives, ketolactam fullerene derivatives, and azafulleroid fullerene derivatives. It is done. Specific examples of these structures include those described in publicly known documents such as International Publication No. 2011-016430, Japanese Unexamined Patent Publication No. 2012-191194, or Japanese Unexamined Patent Publication No. 2011-504168. Two or more fullerene derivatives may be used. Among them, fullerene derivatives are [6,6] -phenyl-C ₆₁ -butyric acid methyl ester ([60] PCBM), [6,6] -phenyl-C ₇₁ -butyric acid methyl ester ([70] PCBM), or A mixture thereof is preferred.

  The material of the hole extraction layer is not particularly limited as long as it can improve the efficiency of extracting holes from the active layer to the anode. For example, polythiophene, polypyrrole, polyacetylene, triphenylenediamine, or Conductive compounds such as polyaniline doped with sulfonic acid and / or iodine, polythiophene derivatives having a sulfonyl group as a substituent, conductive compounds such as conductive organic compounds such as arylamine; copper oxide, nickel oxide, oxidized Examples thereof include metal oxide semiconductors such as manganese, molybdenum oxide, vanadium oxide and tungsten oxide, and semiconductor compounds such as Nafion and p-type semiconductors described later. Preferred is a conductive polymer doped with sulfonic acid, and more preferred is (3,4-ethylenedioxythiophene) poly (styrene sulfonic acid) (PEDOT: PSS) in which a polythiophene derivative is doped with polystyrene sulfonic acid. .

  The thickness of the buffer layer is not particularly limited, but when a semiconductor compound is used as the buffer layer material, it is preferably 10 nm or more and more preferably 30 nm or more in order to improve electron or hole extraction efficiency. Preferably, it is particularly preferably 50 nm or more. On the other hand, in order to keep the internal resistance of the organic solar cell element low and improve the conversion efficiency of the organic solar cell element, it is preferably 300 nm or less, and 200 nm or less. Is more preferable, and 100 nm or less is particularly preferable. On the other hand, when a conductive compound is used as the buffer layer material, it is preferably 10 nm or more, more preferably 50 nm or more, and particularly preferably 100 nm or more in order to improve electron or hole extraction efficiency. On the other hand, in order to keep the internal resistance of the organic solar cell element low and improve the conversion efficiency of the organic solar cell element, it is preferably 1000 nm or less, more preferably 700 nm or less, and particularly preferably 500 nm or less. preferable.

The formation method of the electron extraction layer and the hole extraction layer is not particularly limited, and can be formed by a known method according to the material to be used. For example, when a material having sublimation property is used, it can be formed by a vacuum evaporation method such as an evaporation method or a sputtering method. Further, when a material soluble in a solvent is used, it can be formed by a wet coating method such as spin coating or ink jet. Moreover, when using a semiconductor material, you may convert a precursor into a semiconductor compound, after forming a layer using a precursor like the low molecular organic-semiconductor compound of an active layer.
<1-4. Current collector 7>
The current collector 7 is a wiring for taking out electricity generated by the solar cell element to the outside. Specifically, electricity generated in the solar cell element can be taken out by connecting to the upper electrode and / or the lower electrode of the solar cell element 4.

  Examples of the material for the current collecting wire include metals and alloys. Among them, copper, aluminum, silver, gold, nickel and the like having low resistivity are preferably used, and copper and aluminum are particularly preferable because they are inexpensive. In order to prevent rust, the current collector may be plated with tin, silver or the like, the surface may be coated with resin, or a film may be laminated. Examples of the shape of the current collecting wire include a flat wire, a foil, a flat plate, and a wire shape. For reasons such as securing a bonding area, it is preferable to use a flat wire, a foil, or a flat plate. Moreover, since a current collection line can be used as an electrical extraction terminal, it is more preferable that it is flat form.

  In the present specification, “foil” means a material having a thickness of less than 100 μm, and “plate” means a material having a thickness of 100 μm or more. The term “flat wire” refers to a wire having a circular cross section and having a quadrangular cross section.

  The current collector is not particularly limited as long as it has electrical conductivity, but preferably has a lower resistance value than the upper electrode and lower electrode to be connected, and in particular, by increasing the thickness of the upper electrode and lower electrode, It is preferable to reduce the value. The thickness of the current collector is preferably 5 μm or more, more preferably 10 μm or more. Moreover, it is preferable that it is 2 mm or less, More preferably, it is 1 mm or less, More preferably, it is 500 micrometers or less, Most preferably, it is 300 micrometers or less. When the thickness of the current collection line is equal to or more than the above lower limit, an increase in the resistance value of the current collection line can be suppressed, and the generated power can be efficiently taken out to the outside. In addition, when the amount is not more than the above upper limit, the weight of the thin film solar cell module increases and the flexibility decreases, the surface of the thin film solar cell module is likely to be uneven, and the production cost increases. May occur.

  The width | variety of a current collection line is 0.5 mm or more in general, Preferably it is 1 mm or more, More preferably, it is 2 mm or more, and is 50 mm or less normally, Preferably it is 20 mm or less, More preferably, it is 10 mm or less. By making the width | variety of a current collection line more than the said minimum, the raise of the resistance value of a current collection line can be suppressed and the generated electric power can be taken out efficiently. Moreover, the mechanical strength of the current collector can be maintained, and breakage and the like can be suppressed. By being below the upper limit, the aperture ratio of the entire module can be maintained, and a decrease in the amount of power generated by the module can be suppressed.

  In addition, there is no special restriction | limiting in the method of connecting a collector wire with the electrode of a solar cell element, What is necessary is just to connect by a well-known method. For example, it can be connected with a conductive adhesive, a conductive tape, solder, etc., and it is preferable to connect with a conductive adhesive. A well-known thing can be used as a conductive adhesive, For example, conductive adhesives, such as thermoplasticity and thermosetting, can be used.

In addition, a thin film solar cell module is not limited to the structure of FIG. 2, As long as it functions as a thin film solar cell module, there is no special restriction | limiting in the structure. For example, the structures of the protective film 8 and the protective film 9 may be the same or different. Moreover, the structure which does not provide the protective film 8 comprised from the barrier layer 1 and the sealing layer 2 may be sufficient. In the case of such a configuration, it is preferable to increase the barrier performance by laminating an inorganic layer corresponding to the barrier material layer on the element substrate 3. The inorganic layer is not particularly limited, but the above <1-1-1. The inorganic layer mentioned in the item of barrier layer (1, 6)> can be used. In this case, it is preferable that the water vapor permeability of the protective film 9 in an environment of 40 ° C. and 90% RH is 1 × 10 ⁻⁴ g / m ² / day or more and 1 × 10 ⁻³ g / m ² / day or less. .

<2. Manufacturing method of thin film solar cell module>
The manufacturing method of the thin film solar cell module according to the present embodiment is not particularly limited, and can be formed by any method as long as the above configuration is obtained. For example, a thin film solar cell module can be manufactured by the process of forming the solar cell element 4 on the element substrate 3 and the sealing process of sealing the element substrate 3 on which the solar cell element 4 is formed.

<2-1. Step of forming solar cell element 4 on element substrate 3>
The method for forming the solar cell element 4 on the element substrate 3 is not particularly limited. As described in the solar cell element 4>, the layers constituting the solar cell element 3 can be formed by being sequentially laminated.

  Each layer constituting the solar cell element 4 may be formed by a single-wafer type or a roll-to-roll method. However, in order to improve productivity, it is preferable to form each layer or at least a part of layers by a roll-to-roll method.

  In addition, the thin film solar cell module may be comprised by one solar cell element, and may be comprised by the several solar cell element connected in series. Furthermore, the structure which has several solar cell elements connected in series, and was mutually connected in parallel may be sufficient. When the thin film solar cell module has a configuration in which a plurality of solar cell elements are connected in series, a serialized structure may be formed using a known laser-scribe method or the like after each layer is formed.

<2-2. Sealing process of solar cell element 3>
In order to seal the solar cell element 4 and the element substrate 3, a resin composition for forming a sealing layer is applied to each of the barrier layers 1 and 6, or a laminate is formed by stacking sheet-shaped resin compositions. The laminated body may be laminated and sealed by a known method so that the side on which the resin composition is provided is on the solar cell element 4 and element substrate 3 side. The sealing method is not particularly limited and may be performed by a known method such as vacuum lamination or roll lamination.

  Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of the following examples unless it exceeds the gist.

  In addition, the measurement of the water vapor | steam transmittance | permeability of the barrier film as described in a following example and a thin film solar cell module, oxygen permeability, and the measurement of the conversion efficiency of a thin film solar cell module were performed with the following method.

<Measurement method of water vapor transmission rate of protective film>
The average value measured twice based on the differential pressure method using a TECHNOLOX water vapor permeability measuring device and DELTAPERRM under the conditions of a temperature of 40 ° C. and a humidity of 90% RH was cut out to a size of 100 mm for each barrier film. Calculated.

<Measurement method of oxygen permeability of protective film>
A protective film is cut out to a size of 100 mm, and the method described in JIS K 7126-2 (isobaric method) using an oxygen transmission rate measuring device manufactured by MOCON and OXTRAN under conditions of a temperature of 40 ° C. and a humidity of 0%. Based on the above, the average value measured twice was calculated.

<Measurement method of conversion efficiency of thin film solar cell module>
The thin film solar cell module was irradiated with light with a solar simulator (manufactured by Spectrometer Co., Ltd.) under AM1.5G conditions (irradiation intensity 1000 W / cm ² ), and the energy conversion efficiency (PCE) was calculated from the obtained current / voltage curve. Asked.

<Example 1: Production of thin film solar cell module>

  On one side of a polyethylene naphthalate film (Q65 manufactured by Teijin DuPont Films, Inc., 100 μm thick) prepared as a solar cell element substrate, a first indium oxide layer having a thickness of 50 nm, a silver layer having a thickness of 8 nm, and a thickness are formed by sputtering. A second indium oxide layer having a thickness of 30 nm was laminated in this order to form a lower electrode.

  Next, a 50-nm-thick zinc oxide layer was formed as an electron extraction layer on the lower electrode by the method described in Japanese Patent Application Laid-Open No. 2015-127408.

  Next, an active layer having a thickness of 320 nm was formed on the zinc oxide layer. Specifically, a mixture containing a polymer organic semiconductor and phenyl C61 fullerene butyric acid methyl ester (PCBM) in a weight ratio of 1: 2.5 is applied using a solution in which the mixture is dissolved in an organic solvent so as to be 6% by mass. Formed by.

  Next, a PEDOT: PSS layer having a thickness of 400 nm was formed on the active layer as a hole extraction layer. Specifically, the PEDOT: PSS layer was ultrasonically dispersed in the PEDOT: PSS dispersion and allowed to stand for 96 hours. After that, the PEDOT: PSS layer was applied on the active layer by a doctor blade method and dried in a nitrogen atmosphere at 145 ° C. for 30 minutes. Formed.

  Next, a silver layer having a thickness of 8 nm and an indium oxide layer having a thickness of 40 nm were stacked in this order on the hole extraction layer by a sputtering method to form an upper electrode. Thus, a solar cell element was produced on the solar cell element substrate.

  Next, a collector wire with a conductive thermosetting resin composition (DT101C4 manufactured by Dexerials, (Epoxy conductive curable resin containing nickel particles as conductive particles, curing temperature 120 ° C.) 15 μm + copper foil 35 μm thickness, width 4 mm) installed.

Next, 3 μm of urethane acrylate was applied to one surface of a 50 μm thick polyethylene terephthalate substrate and cured. A barrier film A was prepared by sputtering SiO ₂ having a thickness of 200 nm on the urethane acrylate film. The barrier film 1 thus prepared had a water vapor transmission rate in the environment of 40 ° C. and 90% RH and an oxygen transmission rate in the environment of 40 ° C. and 0% humidity, respectively 5 × 10 ⁻⁴ g / m ² / day, 8 × 10. ^-3 cc / m ² / day / atm. Subsequently, two laminates were prepared by laminating an olefin resin having a thickness of 50 μm (Kurabo Co., Ltd., Clanbetter) as a sealing layer on the created barrier film A.

Next, in order from the bottom, the laminate, the solar cell element, and the solar cell substrate prepared by the above method so as to become the barrier film A, the sealing layer, the element substrate, the solar cell element, the sealing layer, and the barrier film A. Again, it was put into a vacuum laminator (NLM-270 × 400, manufactured by NPC). First, the inside of the laminator is held for 15 minutes under reduced pressure, and then the laminated body is held at 120 ° C. for 10 minutes while being pressure-bonded at atmospheric pressure, and then immediately cooled to room temperature, and the thin film solar cell module shown in FIG. Got. In addition, both the water vapor transmission rate in the 40 ° C. and 90% RH environment and the oxygen transmission rate in the 40 ° C. and 0% humidity environment of the laminate of the sealing layer and the barrier film A corresponding to the protective film are both barrier film A. It was 5 × 10 ⁻⁴ g / m ² / day and 8 × 10 ⁻³ cc / m ² / day / atm, respectively.

  The initial conversion efficiency of the obtained thin film solar cell module was measured. In addition, in order to examine the durability of the thin film solar cell module, the thin film solar cell module is placed in a constant temperature bath held in an environment of 65 ° C. and 85% RH, and the conversion efficiency after 600 hours is measured. The module durability was evaluated by the following formula. The obtained results are shown in Table 1.

<Judgment criteria for module durability>
Determination was made according to the conversion efficiency maintenance ratio calculated by the following equation.
Conversion efficiency maintenance rate = (65 ° C., 85% RH, conversion efficiency after 600 hours) / (initial conversion efficiency) × 100
○: Conversion efficiency maintenance ratio is 90% or more Δ: Conversion efficiency maintenance ratio is 80% or more and less than 90% ×: Conversion efficiency maintenance ratio is less than 80%

<Comparative Example 1: Production of thin film solar cell module>
A thin film solar cell module was produced in the same manner as in Example 1 except that the barrier film A was changed to the following organic and inorganic multilayer barrier film (barrier film B), and the same evaluation was performed.

On one side of a polyethylene naphthalate film (Q65 manufactured by Teijin DuPont Films Co., Ltd., 100 μm thick), 14 parts by mass of EB-3702 manufactured by Daicel Cytec Co., Ltd. and IRGCURE907, a polymerization initiator manufactured by Ciba Specialty Chemicals Co., Ltd. A composition composed of 185 parts by mass of 2-part butanone was applied, and an organic polymer layer having a thickness of 400 nm was obtained by ultraviolet curing. Next, Al ₂ O ₃ was deposited on the surface of the organic polymer layer by vacuum sputtering so as to have a thickness of 35 nm, thereby forming an inorganic layer of Al ₂ O ₃ . In the same manner, an organic polymer 400 nm and Al ₂ O ₃ were sequentially formed on the Al ₂ O ₃ layer to prepare a barrier film B having a multilayer barrier film of an organic compound and an inorganic compound. The barrier film B thus prepared had a water vapor transmission rate in an environment of 40 ° C. and 90% RH and an oxygen transmission rate in an environment of 40 ° C. and 0% humidity, respectively 8 × 10 ⁻⁵ g / m ² / day, 5 × 10 ^-3 cc / m ² / day / atm. Moreover, both the water vapor transmission rate in the environment of 40 ° C. and 90% RH and the oxygen transmission rate in the environment of 40 ° C. and 0% humidity of the laminate of the sealing layer and the barrier film B corresponding to the protective film are both barrier films. It was dependent on B and was 8 × 10 ⁻⁵ g / m ² / day and 5 × 10 ⁻³ cc / m ² / day / atm, respectively.

<Comparative Example 2: Production of thin film solar cell module>
Except for changing barrier film A to VIEW-BARRIER, VDK3DA (barrier film C, water vapor transmission rate 5 × 10 ⁻³ g / m ² / day under the environment of 40 ° C. and 90% RH) manufactured by Mitsubishi Plastics A thin film solar cell module was produced by the same method as in Example 1, and the same evaluation was performed. The obtained results are shown in Table 1. In addition, the water vapor transmission rate in a 40 ° C. and 90% RH environment and the oxygen transmission rate in a 40 ° C. and 0% humidity environment of the laminate of the sealing layer and the barrier film C corresponding to the protective film are respectively a barrier film. It was dependent on C and was 5 × 10 ⁻³ g / m ² / day and 1 × 10 ⁻² cc / m ² / day / atm.

It can be seen that the thin film solar cell module of Example 1 has a high conversion efficiency maintenance rate after 600 hours have passed under an environment of 65 ° C. and 85% RH, and has the same power generation performance as the initial stage. On the other hand, in the thin-film solar cell modules of Comparative Examples 1 and 2, it can be seen that the conversion efficiency maintenance ratio after 600 hours is low, and the conversion efficiency is reduced from the beginning. The barrier film used in the thin film solar cell module of Example 1 has a water vapor transmission rate of 40 ° C. and 90% RH in an environment of 1 × 10 ⁻³ g / m ² / day or more, and 1 × 10 ⁻⁴ g / m ² / day. It is considered that the deterioration of the solar cell element caused by oxygen is improved by the small amount of water entering the thin film solar cell module in a high temperature and high humidity environment within the following range.

DESCRIPTION OF SYMBOLS 1, 6 Barrier film 2, 5 Sealing layer 3 Element board | substrate 4 Solar cell element 7 Current collection line 8, 9 Protective film

Claims (4)

At least a thin film solar cell module having an element substrate, a solar cell element, and a protective film,
A thin film characterized in that the protective film has a water vapor transmission rate of 1 × 10 ⁻⁴ g / m ² / day or more and 1 × 10 ⁻³ g / m ² / day or less in a 40 ° C. and 90% RH environment. Solar cell module. The oxygen permeability of the protective film in an environment of 40 ° C. and 0% humidity is 1 × 10 ⁻³ cc / m ² / day / atm or more and 1 × 10 ⁻² cc / m ² / day / atm or less. The thin film solar cell module according to claim 1.   The solar cell element has at least a pair of electrodes and an active layer between the pair of electrodes, and the active layer contains an organic semiconductor compound or a perovskite semiconductor compound. 2. The thin film solar cell module according to 2.   The solar cell element has an electron extraction layer between at least one electrode of the pair of electrodes and the active layer, and at least one of the active layer or the electron extraction layer contains fullerene or a fullerene derivative. The thin film solar cell module according to any one of claims 1 to 3, wherein

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