JP2015090935A - Thin film solar cell module and thin film solar cell array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film solar cell module suitable for providing a large area thin film solar cell array formed by coupling modules.SOLUTION: The thin film solar cell module is formed by encapsulating a thin film solar cell element on which two or more collection wires are installed. Both ends of at least two collection wires among the two or more collection wires are exposed to outside of an encapsulation structure.

Description

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

  As a thin film solar cell module, a thin film solar cell module having a structure in which a plurality of thin film solar cell submodules are sealed is known (see Patent Document 1).

JP 2004-253472 A

A conventional thin film solar cell array has a structure in which a plurality of thin film solar cells are electrically connected by wiring and then sealed. However, when a thin film solar cell is an organic solar cell, it is generally vulnerable to water and oxygen. When connecting an organic thin film solar cell by wiring, it is preferable to seal the organic thin film solar cell with a barrier member in advance.
In order to install the current collector after sealing the organic thin film solar cell with the barrier member, it is necessary to remove the barrier member at the location where the current collector is installed. It may damage the solar cell. Therefore, it is necessary to seal the organic thin-film solar cell once in a state where a collector wire is installed in advance on the organic thin-film solar cell, and then connect the sealed organic thin-film solar cell modules to each other.

If the position where electricity is taken out from the organic thin film solar cell module is determined, the degree of freedom of wiring is lowered and it takes time to connect the modules. As a result of the long wiring connecting the modules, the electrical resistance of the connected modules increases and the photoelectric conversion efficiency (PCE) decreases. Moreover, as a result of the length of the current collecting line, the module becomes hard and the flexibility is lowered. In addition, the current collector tends to buckle, which tends to cause poor appearance and poor electrical characteristics.
On the other hand, when the module is designed so that the wiring of the module in the organic thin-film solar cell array is minimized, every time the organic thin-film solar cell array is designed, modules with various electrical extraction positions are manufactured. As a result, the module manufacturing becomes complicated, and as a result, the yield of the organic thin-film solar cell array decreases.
This invention solves such a problem, and makes it a subject to provide the thin film solar cell module suitable for installation of a large area.

  In order to solve the above-mentioned problems, the present inventors examined the wiring extraction position of the thin film solar cell module. As a result, at least one, preferably two or more of the two or more current collectors installed in the thin film solar cell module, both ends are exposed to the outside of the sealing structure of the thin film solar cell module. In addition, the present invention was completed by finding out that the electrical connection between the thin-film solar cell modules was facilitated by installing and sealing. The outline of the present invention is as follows.

A thin-film solar cell module encapsulating a thin-film solar cell element on which two or more current collectors are installed,
Both ends of at least two current collectors of the two or more current collectors are exposed outside the sealing structure.
It is a thin film solar cell module.

In the thin film solar cell element, a plurality of solar cells are preferably connected monolithically.
Moreover, it is preferable that the said thin film solar cell element is an organic thin film solar cell element.
Another embodiment of the present invention is a thin film solar cell array formed by connecting a plurality of the above thin film solar cell modules.

The present invention has a structure in which both ends of the current collector installed in the solar cell module are exposed outside the sealing structure of the thin film solar cell module. An electrode extraction pattern can be made.
Also, when installing an actual thin-film solar cell array, the electrode extraction position can be determined (unused collectors can be cut off during installation. They can be left as they are), so the thin-film solar cell prepared as a spare part One type of module is sufficient.
In addition, it is easier to handle the current collector, and the positive and negative positions can be reversed during construction due to the voltage and sunshine.
Moreover, since the wiring is shortened, a voltage drop at the time of electricity extraction can be suppressed, and the connection is simple and the manufacturing efficiency of the thin film solar cell array is increased.
Moreover, as a result of shortening the connection between the thin film solar cell modules, the electrical resistance in the modules is reduced and the photoelectric conversion efficiency (PCE) is increased.
Moreover, the flexibility of a module improves as a result of shortening a current collection line. In addition, buckling of the collector line is less likely to occur, and poor appearance and poor electrical characteristics are less likely to occur.

It is a cross-sectional schematic diagram which shows the layer structure of an organic thin film solar cell. It is a cross-sectional schematic diagram showing the layer structure of an organic thin film solar cell module. It is the schematic diagram which looked at the organic thin film solar cell module from the upper surface. In the organic thin-film solar cell array which concerns on the embodiment of this invention, the example (a) which connected each organic thin-film solar cell module in parallel, and the example (b) and (c) connected directly are shown. In the organic thin film solar cell array which concerns on a prior art, the example (a) which connected each organic thin film solar cell module in parallel, and the example (b) connected directly are shown.

The present invention will be described in detail below, but the present invention is not limited to specific embodiments.
The thin film solar cell module of the present invention is a thin film solar cell module in which an organic thin film solar cell element provided with two or more current collectors is sealed, and both ends of at least two of the current collectors are sealed. It is outside the stop structure. Usually, two current collectors are installed, but three or more current collectors can be installed according to the purpose.

  In the present invention, examples of the thin film solar cell element include thin film single crystal silicon, thin film polycrystalline silicon, amorphous silicon, organic dye material, and organic semiconductor material. The thin film solar cell element has a thickness of usually 1 μm or more, preferably 10 μm or more, more preferably 25 μm or more. Moreover, it is 800 micrometers or less normally, Preferably it is 500 micrometers or less, More preferably, it is 300 micrometers or less. Of these thin film solar cell elements, organic thin film solar cell elements are preferable. Hereinafter, an organic thin film solar cell element will be described as a typical embodiment of the thin film solar cell element.

1 Organic thin-film solar cell element An organic thin-film solar cell element generally comprises at least a pair of electrodes, an organic active layer present between the electrodes, and an electron extraction layer present between the organic active layer and one of the electrodes And have. FIG. 1 shows a general layer structure of an organic thin film solar cell element. An organic thin film solar cell element 107 shown in FIG. 1 includes a solar cell element substrate 106, a lower electrode 101 as a cathode, an electron extraction layer 102, an active layer 103 (a layer containing a p-type semiconductor compound and an n-type semiconductor material), It has a layer structure in which a hole extraction layer 104 and an upper electrode 105 as an anode are sequentially formed. In FIG. 1, the lower electrode 101 exists above the upper electrode 105. In this specification, the upper electrode and the lower electrode refer to the upper electrode and the lower electrode when the solar cell element substrate 106 is the bottom. The electrode laminated on the solar cell element substrate is referred to as a lower electrode. In addition, the electron extraction layer 102, the active layer 103, and the hole extraction layer 104 may be collectively referred to as an organic layer.

1.1 Solar Cell Element Substrate A solar cell element substrate (hereinafter also referred to as an element substrate) is a member for holding and forming an organic thin film solar cell element, and the type thereof is not particularly limited as long as it has the function.
The material for the element substrate is not particularly limited as long as the effects of the present invention are not significantly impaired. Suitable examples of the element substrate material include inorganic materials such as quartz, glass, sapphire, and titania; polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, Fluoropolymer film, polyolefin such as vinyl chloride or polyethylene; organic material such as cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene or epoxy resin; paper material such as paper or synthetic paper; stainless steel Examples thereof include composite materials such as those obtained by coating or laminating a surface of a metal such as titanium or aluminum to impart insulation.
In the case of a flexible and flexible film-like element substrate, organic materials, paper materials, and composite materials are preferable, organic materials and composite materials are more preferable, and organic materials are particularly preferable.

Moreover, although there is no restriction | limiting in the film thickness of an element substrate, it is 5 micrometers or more normally, Preferably it is 20 micrometers or more, on the other hand, it is 20 mm or less normally, Preferably it is 10 mm or less. It is preferable that the thickness of the element substrate is 5 μm or more because the possibility that the strength of the organic thin film solar cell is insufficient is reduced. It is preferable that the thickness of the element substrate is 20 mm or less because the cost is suppressed and the weight does not increase.
The element substrate may be transparent or opaque. When the substrate is transparent, light can be incident from the substrate side.

1.2 Electrode The organic thin film solar cell element has an organic photoelectric conversion layer which is an organic semiconductor layer and a pair of electrodes (first electrode and second electrode). In one embodiment, a lower electrode is laminated on a film substrate to constitute a laminate, and laser processing can be performed on the laminate. In addition, after the organic photoelectric conversion layer is stacked, laser processing can be performed on the stacked body on which the upper electrode is stacked. The pair of electrodes usually means an anode and a cathode described below, but the lower electrode may be an anode, the upper electrode may be a cathode, the lower electrode is a cathode, and the upper electrode is an anode. May be.

The pair of electrodes has a function of collecting holes and electrons generated by light absorption. Accordingly, the pair of electrodes includes an electrode suitable for collecting holes (hereinafter sometimes referred to as an anode) and an electrode suitable for collecting electrons (hereinafter sometimes referred to as a cathode). It is preferable to use it. Any one of the pair of electrodes may be translucent, and both may be translucent. Translucency means that sunlight passes through 40% or more. Moreover, it is preferable that the sunlight transmittance of the transparent electrode is 70% or more in order to allow light to reach the photoelectric conversion layer through the transparent electrode. The light transmittance can be measured with a normal spectrophotometer.

The anode is an electrode generally made of a conductive material having a work function higher than that of the cathode and having a function of smoothly taking out holes generated in the organic photoelectric conversion layer.
Examples of anode materials include conductive metal oxides such as nickel oxide, tin oxide, indium oxide, indium tin oxide (ITO), indium-zirconium oxide (IZO), titanium oxide, indium oxide, and zinc oxide; Examples thereof include metals such as gold, platinum, silver, chromium and cobalt, or alloys thereof. These substances are preferable because they have a high work function, and further, a conductive polymer material represented by PEDOT: PSS in which a polythiophene derivative is doped with polystyrene sulfonic acid can be stacked. When laminating such a conductive polymer, the work function of this conductive polymer material is high, so even if it is not a material with a high work function as described above, it is suitable for cathodes such as Al and Mg. Metals can also be widely used. PEDOT: PSS in which a polythiophene derivative is doped with polystyrene sulfonic acid, or a conductive polymer material in which polypyrrole, polyaniline, or the like is doped with iodine or the like can also be used as an anode material. When the anode is a transparent electrode, it is preferable to use a light-transmitting conductive metal oxide such as ITO, zinc oxide or tin oxide, and ITO is particularly preferable.

The film thickness of the anode is not particularly limited, but is usually 10 nm or more, preferably 20 nm or more, and more preferably 50 nm or more. On the other hand, it is usually 10 μm or less, preferably 1 μm or less, more preferably 500 nm or less. When the anode film thickness is equal to or greater than the above lower limit, sheet resistance is suppressed, and when the anode film thickness is equal to or less than the above upper limit, light can be efficiently converted into electricity without reducing light transmittance. it can. When the anode is a transparent electrode, it is necessary to select a film thickness that can achieve both light transmittance and sheet resistance.
The sheet resistance of the anode is not particularly limited, but is usually 1Ω / □ or more, on the other hand, 1000Ω / □ or less, preferably 500Ω / □ or less, more preferably 100Ω / □ or less.
Examples of the anode forming method include a vacuum film forming method such as a vapor deposition method or a sputtering method, or a wet coating method in which an ink containing nanoparticles or a precursor is applied to form a film.

The cathode is generally an electrode made of a conductive material having a low work function and having a function of smoothly extracting electrons generated in the photoelectric conversion layer. The cathode is adjacent to the electron extraction layer.
Examples of cathode materials include platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, cesium, calcium, and magnesium, and alloys thereof; lithium fluoride And inorganic salts such as cesium fluoride and metal oxides such as nickel oxide, aluminum oxide, lithium oxide, and cesium oxide. These materials are preferable because they are materials having a low work function. Similarly to the anode, a material having a high work function can be used for the cathode by using an n-type semiconductor such as titania having conductivity as the electron extraction layer. From the viewpoint of electrode protection, the cathode material is preferably a metal such as platinum, gold, silver, copper, iron, tin, aluminum, calcium or indium, or an alloy using these metals such as indium tin oxide.

The film thickness of the cathode is not particularly limited, but is usually 10 nm or more, preferably 20 nm or more, more preferably 50 nm or more. On the other hand, it is usually 10 μm or less, preferably 1 μm or less, more preferably 500 nm or less. When the cathode film thickness is equal to or greater than the lower limit, sheet resistance is suppressed, and when the cathode film thickness is equal to or less than the upper limit, light can be efficiently converted into electricity without reducing light transmittance. it can. When the cathode is a transparent electrode, it is necessary to select a film thickness that achieves both light transmittance and sheet resistance.
The sheet resistance of the cathode is not particularly limited, but is usually 1000Ω / □ or less, preferably 500Ω / □ or less, and more preferably 100Ω / □ or less. Although there is no restriction on the lower limit, it is usually 1Ω / □ or more.
As a method for forming the cathode, there are a vacuum film formation method such as a vapor deposition method or a sputtering method, or a wet coating method in which an ink containing nanoparticles or a precursor is applied to form a film.

Furthermore, the anode and the cathode may have a laminated structure of two or more layers. In addition, characteristics (electric characteristics, wetting characteristics, etc.) may be improved by performing surface treatment on the anode and the cathode.
After laminating the anode and cathode, the organic thin-film solar cell element is heated in a temperature range of usually 50 ° C. or higher, preferably 80 ° C. or higher, usually 300 ° C. or lower, preferably 280 ° C. or lower, more preferably 250 ° C. or lower. It is preferable to do this (this step may be referred to as an annealing treatment step). By performing the annealing process at a temperature of 50 ° C. or higher, the adhesion between the layers of the organic thin film solar cell element, for example, the adhesion between the electron extraction layer and the cathode and / or the electron extraction layer and the organic photoelectric conversion layer is improved. Is preferable. By improving the adhesion between the layers, the thermal stability and durability of the organic thin film solar cell element can be improved. It is preferable to set the temperature of the annealing treatment step to 300 ° C. or lower because the organic compound in the organic photoelectric conversion layer is less likely to be thermally decomposed. In the annealing treatment step, stepwise heating may be performed within the above temperature range.

The heating time is usually 1 minute or longer, preferably 3 minutes or longer, and usually 3 hours or shorter, preferably 1 hour or shorter. The annealing treatment step is preferably terminated when the open-circuit voltage, the short-circuit current, and the fill factor, which are parameters of the solar cell performance, reach a constant value. Further, the annealing treatment step is preferably performed under normal pressure and in an inert gas atmosphere.
As a heating method, the organic thin film solar cell element may be placed on a heat source such as a hot plate, or the organic thin film solar cell element may be placed in a heating atmosphere such as an oven. The heating may be performed batchwise or continuously.

1.3 Buffer layer (electron extraction layer, hole extraction layer)
The organic thin-film solar cell element according to this embodiment has at least a pair of electrodes and an organic photoelectric conversion layer that exists between the electrodes, but usually exists between the organic photoelectric conversion layer and one of the electrodes. An electron extraction layer. Usually, an electron extraction layer is provided between the cathode and the organic photoelectric conversion layer. The organic thin film solar cell element has a hole extraction layer between the organic photoelectric conversion layer and the anode. The electron extraction layer and / or the hole extraction layer may be referred to as a buffer layer. The electron extraction layer and the hole extraction layer are not essential.

In this embodiment, it is preferable to have a buffer layer between the organic photoelectric conversion layer and the electrode, and it is more preferable to have a buffer layer between the organic photoelectric conversion layer and the upper electrode. By having a buffer layer, damage during laser processing can be reduced. The buffer layer in this case may be either an electron extraction layer or a hole extraction layer, but the film thickness is preferably 0.1 nm or more.
The thickness of the electron extraction layer is usually 0.1 nm or more, preferably 1 nm or more, more preferably 10 nm or more. On the other hand, it is usually 400 nm or less, preferably 200 nm or less. When the film thickness of the electron extraction layer is equal to or more than the above lower limit, the function as a buffer material is achieved. When the film thickness of the electron extraction layer is equal to or less than the above upper limit, electrons are easily extracted and the photoelectric conversion efficiency is increased. Can improve.

The film thickness of the hole extraction layer is usually 0.1 nm or more. On the other hand, it is usually 400 nm or less, preferably 200 nm or less. When the film thickness of the hole extraction layer is not less than the above lower limit, it functions as a buffer material. When the film thickness of the hole extraction layer is not more than the above upper limit, holes can be easily extracted, Conversion efficiency can be improved.
The electron extraction layer and the hole extraction layer are preferably disposed so as to sandwich the organic photoelectric conversion layer between a pair of electrodes. That is, when the organic thin film solar cell element includes both an electron extraction layer and a hole extraction layer, the upper electrode, the hole extraction layer, the organic photoelectric conversion layer, the electron extraction layer, and the lower electrode can be disposed in this order. . When the organic thin film solar cell element includes an electron extraction layer and does not include a hole extraction layer, the upper electrode, the organic photoelectric conversion layer, the electron extraction layer, and the lower electrode can be disposed in this order. The stacking order of the electron extraction layer and the hole extraction layer may be reversed, or at least one of the electron extraction layer and the hole extraction layer may be composed of a plurality of different films.

1.3.1 Electron Extraction Layer The material of the electron extraction layer is not particularly limited as long as it is a material that improves the efficiency of extracting electrons from the organic photoelectric conversion layer to the cathode, and examples thereof include inorganic compounds and organic compounds.
Examples of the material of the inorganic compound 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 compound materials include, for example, phosphine compounds having a double bond between a phosphorus atom and a group 16 element such as triarylphosphine oxide compounds; bathocuproin (BCP) or bathophenanthrene (Bphen), A phenanthrene compound which may have a substituent and may be substituted at the 1-position and the 10-position with a heteroatom; a boron compound such as triarylboron; and (8-hydroxyquinolinato) aluminum (Alq3) Organometallic 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 acid Of dicarboxylic anhydrides, such as anhydrides (PTCDA) Aromatic compounds having Unachijimigo dicarboxylic acid structure.

  The LUMO energy level of the material of the electron extraction layer is not particularly limited, but is usually −4.0 eV or more, preferably −3.9 eV or more. On the other hand, it is usually −1.9 eV or less, preferably −2.0 eV or less. It is preferable that the LUMO energy level of the material for the electron extraction layer is −1.9 eV or less because charge transfer can be promoted. It is preferable that the LUMO energy level of the material for the electron extraction layer is −4.0 eV or more in terms of preventing reverse electron transfer to the n-type semiconductor material.

  The HOMO energy level of the material for the electron extraction layer is not particularly limited, but is usually −9.0 eV or more, preferably −8.0 eV or more. On the other hand, it is usually −5.0 eV or less, preferably −5.5 eV or less. The HOMO energy level of the material for the electron extraction layer is preferably −5.0 eV or less from the viewpoint of preventing movement of holes.

  As a method for calculating the LUMO energy level and the HOMO energy level of the material of the electron extraction layer, a cyclic voltammogram measurement method may be mentioned. For example, it can implement with reference to the method as described in well-known literature (International Publication 2011/016430).

  When the material of the electron extraction layer is an organic compound, the glass transition temperature (hereinafter sometimes referred to as Tg) of this compound as measured by the DSC method is not particularly limited, but is not observed, or It is preferable that it is 55 degreeC or more. That the glass transition temperature is not observed by the DSC method means that there is no glass transition temperature. Specifically, the determination is made based on the presence or absence of a glass transition temperature of 400 ° C. or lower. A material in which the glass transition temperature by the DSC method is not observed is preferable in that it has high thermal stability.

  Among the compounds having a glass transition temperature of 55 ° C. or higher as measured by the DSC method, the glass transition temperature is preferably 65 ° C. or higher, more preferably 80 ° C. or higher, more preferably 110 ° C. or higher, particularly preferably. Compounds that are 120 ° C. or higher are desirable. On the other hand, the upper limit of the glass transition temperature is not particularly limited, but is usually 400 ° C. or lower, preferably 350 ° C. or lower, more preferably 300 ° C. or lower. Moreover, it is preferable that the material of an electron taking-out layer is a thing by which the glass transition temperature by DSC method is not observed below 30 degreeC or more and less than 55 degree | times.

  The glass transition temperature in the present specification is defined as a point at which specific heat changes in an amorphous solid, which is a temperature at which local molecular motion is started by thermal energy. When the temperature rises further than Tg, the solid structure changes and crystallization occurs (the temperature at this time is defined as the crystallization temperature (Tc)). When the temperature rises further, it generally melts at the melting point (Tm) and changes to a liquid state. However, these phase transitions may not be observed due to molecular decomposition or sublimation at high temperatures.

  The DSC method is a thermophysical property measurement method (differential scanning calorimetry method) defined in JIS K-0129 “General Rules for Thermal Analysis”. In order to determine the glass transition temperature more clearly, it is desirable to measure after rapidly cooling a sample once heated to a temperature higher than the glass transition temperature. For example, the measurement can be carried out by a method described in a known document (International Publication No. 2011/016430).

  When the glass transition temperature of the compound used for the electron extraction layer is 55 ° C. or higher, the structure of this compound is difficult to change against external stress such as applied electric field, flowing current, stress due to bending or temperature change. It is preferable in terms of durability. Furthermore, since there is a tendency that the crystallization of the thin film of the compound does not proceed easily, the stability of the electron extraction layer is improved by making it difficult for the compound to change between the amorphous state and the crystalline state in the operating temperature range. Therefore, it is preferable in terms of durability. This effect becomes more prominent as the glass transition temperature of the material is higher.

There is no restriction | limiting in the formation method of an electronic taking-out layer. For example, when a material having sublimation property is used, it can be formed by a vacuum deposition method or the like. Further, for example, when a material soluble in a solvent is used, it can be formed by a wet coating method such as spin coating or inkjet.
When the electron extraction layer is formed by a coating method, a surfactant may be further contained in the coating solution. By using the surfactant, the occurrence of dents due to adhesion of fine bubbles or foreign matters and / or uneven coating in the drying process is suppressed. Known surfactants (cationic surfactants, anionic surfactants, nonionic surfactants) can be used as the surfactant. Of these, silicon-based surfactants, acetylenic diol-based surfactants, and fluorine-based surfactants are preferable. In addition, as surfactant, only 1 type may be used and 2 or more types may be used together by arbitrary combinations and a ratio.
Specifically, for example, when an alkali metal salt is used as a material for the electron extraction layer, the electron extraction layer can be formed by using a vacuum film formation method such as vacuum deposition or sputtering. Especially, it is desirable to form an electron taking-out layer by vacuum vapor deposition by resistance heating. By using vacuum deposition, damage to other layers such as an organic photoelectric conversion layer can be reduced.

  On the other hand, for metal oxides of n-type semiconductors, for example, when zinc oxide ZnO is used as the material for the electron extraction layer, a vacuum film formation method such as sputtering can be used. It is desirable to form the extraction layer. For example, Sol-Gel Science, C.I. J. et al. Brinker, G.M. W. According to the sol-gel method described by Scherer, Academic Press (1990), an electron extraction layer composed of zinc oxide can be formed. In this case, the film thickness is usually 0.1 nm or more, preferably 2 nm or more, more preferably 5 nm or more, and usually 1 μm or less, preferably 100 nm or less, more preferably 50 nm or less. If the electron extraction layer is too thin, the effect of improving the electron extraction efficiency is not sufficient, and if it is too thick, the electron extraction layer tends to deteriorate the characteristics of the device by acting as a series resistance component.

1.3.2 Hole Extraction Layer The material of the hole extraction layer is not particularly limited as long as it is a material that can improve the efficiency of extracting holes from the organic photoelectric conversion layer to the anode. Specifically, polythiophene, polypyrrole, polyacetylene, triphenylenediamine, polyaniline, or the like, a conductive polymer doped with sulfonic acid and / or iodine, a polythiophene derivative having a sulfonyl group as a substituent, or a conductive organic such as arylamine Examples thereof include compounds, copper oxide, nickel oxide, manganese oxide, molybdenum oxide, vanadium oxide, metal oxide such as tungsten oxide, Nafion, and a p-type semiconductor described later. Among them, a conductive polymer doped with sulfonic acid is preferable, and (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) (PEDOT: PSS) in which a polythiophene derivative is doped with polystyrene sulfonic acid is more preferable. It is. A thin film of metal such as gold, indium, silver or palladium can also be used. A thin film of metal or the like may be formed alone or in combination with the above organic material.

There is no restriction | limiting in the formation method of a positive hole taking-out layer. For example, when a material having sublimation property is used, it can be formed by a vacuum deposition method or the like. For example, when a material soluble in a solvent is used, it can be formed by a wet coating method such as a spin coating method or an ink jet method. When a semiconductor material is used for the hole extraction layer, the precursor may be converted into a semiconductor compound after the layer is formed using the precursor, similarly to the low-molecular organic semiconductor compound of the organic photoelectric conversion layer described later.
Especially, when using PEDOT: PSS as a material of a hole taking-out layer, it is preferable to form a hole taking-out layer by the method of apply | coating a dispersion liquid. Examples of the dispersion of PEDOT: PSS include CLEVIOSTM series manufactured by Heraeus, ORGACONTM series manufactured by Agfa, and the like.

  When the hole extraction layer is formed by a coating method, a surfactant may be further contained in the coating solution. By using the surfactant, the occurrence of dents due to adhesion of fine bubbles or foreign matters and / or uneven coating in the drying process is suppressed. Known surfactants (cationic surfactants, anionic surfactants, nonionic surfactants) can be used as the surfactant. Of these, silicon-based surfactants, acetylenic diol-based surfactants, and fluorine-based surfactants are preferable. In addition, as surfactant, only 1 type may be used and 2 or more types may be used together by arbitrary combinations and a ratio.

1.4 Organic photoelectric conversion layer (organic semiconductor layer)
The organic photoelectric conversion layer usually includes a p-type semiconductor compound and an n-type semiconductor compound. The p-type semiconductor compound is a compound that works as a p-type semiconductor material, and the n-type semiconductor compound is a compound that works as an n-type semiconductor material. When the organic thin-film solar cell element receives light, the light is absorbed by the organic photoelectric conversion layer, electricity is generated at the interface between the p-type semiconductor compound and the n-type semiconductor compound, and the generated electricity is extracted from the electrode.
An organic compound is preferably used as the material for the organic photoelectric conversion layer because it can be formed by a simple coating process. As the layer structure of the organic photoelectric conversion layer, a thin film stack type in which a p-type semiconductor compound layer and an n-type semiconductor compound layer are stacked, a bulk heterojunction type having a layer in which a p-type semiconductor compound and an n-type semiconductor compound are mixed, Examples include a p-type semiconductor compound layer, a layer in which a p-type semiconductor compound and an n-type semiconductor compound are mixed (i layer), and an n-type semiconductor compound layer stacked. Among these, a bulk heterojunction type having a layer in which a p-type semiconductor compound and an n-type semiconductor compound are mixed is preferable.

  The thickness of the organic photoelectric conversion layer is not particularly limited, but is usually 10 nm or more, preferably 50 nm or more, and is usually 1000 nm or less, preferably 500 nm or less, more preferably 200 nm or less. It is preferable that the thickness of the organic photoelectric conversion layer is 10 nm or more because the uniformity of the film is maintained and a short circuit is less likely to occur. Moreover, it is preferable that the thickness of the organic photoelectric conversion 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.

A method for producing the organic photoelectric conversion layer is not particularly limited, but a coating method is preferable. As the coating method, any method can be used, for example, 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, Examples include the pipe doctor method, the impregnation / coating method, and the curtain coating method.
For example, the p-type semiconductor compound layer and the n-type semiconductor compound layer can be produced by applying a coating liquid containing a p-type semiconductor compound or an n-type semiconductor compound. Moreover, the layer in which the p-type semiconductor compound and the n-type semiconductor compound are mixed can be prepared by applying a coating solution containing the p-type semiconductor compound and the n-type semiconductor compound. As will be described later, the semiconductor compound precursor may be converted into a semiconductor compound after the coating liquid containing the semiconductor compound precursor is applied.
In addition, it is preferable that an organic photoelectric converting layer is manufactured by roll-to-roll, and in that case, it is preferable to form by the apply | coating method.

1.4.1 Photoelectric conversion characteristics The photoelectric conversion characteristics of the organic thin-film solar cell element can be determined as follows. The organic thin-film solar cell element is irradiated with AM1.5G light with a solar simulator at an irradiation intensity of 100 mW / cm ² to measure current-voltage characteristics. From the obtained current-voltage curve, photoelectric conversion characteristics such as photoelectric conversion efficiency (PCE), short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), series resistance, and shunt resistance can be obtained.
The photoelectric conversion efficiency of the organic thin film solar cell element is not particularly limited, but is usually 1% or more, preferably 1.5% or more, and more preferably 2% or more. On the other hand, there is no particular limitation on the upper limit, and the higher the better.
Moreover, as a method for measuring the durability of the organic thin film solar cell element, there is a method for obtaining a maintenance rate of photoelectric conversion efficiency before and after the organic thin film solar cell element is exposed to the atmosphere.
(Maintenance rate) = (Photoelectric conversion efficiency after N hours of atmospheric exposure) / (Photoelectric conversion efficiency immediately before atmospheric exposure)
In order to put an organic thin-film solar cell element into practical use, it is important to have high photoelectric conversion efficiency and high durability in addition to simple and inexpensive manufacture. From this viewpoint, the maintenance rate of photoelectric conversion efficiency before and after exposure to the atmosphere for one week is preferably 60% or more, more preferably 80% or more, and the higher the better.

1.5 Manufacturing Method of Organic Thin Film Solar Cell Element The organic thin film solar cell element according to this embodiment preferably has a monolithic structure in which organic thin film solar cells are connected in series. An example of manufacturing an organic thin film solar cell element having a monolithic structure by laser scribing using a roll-to-roll method is shown below.
A flexible roll film which is an element substrate is prepared, and a lower electrode and a first short-circuit prevention layer are sequentially formed on the roll film by sputtering. For example, PEN is used as the roll film substrate, ITO / Ag / ITO is used as the lower electrode, and ZnO is used as the first short-circuit prevention layer.
A first groove is provided on the laminate by laser scribing. The width of the first groove is usually 50 to 1000 μm, particularly preferably about 100 to 500 μm.

  Next, an electron extraction layer, an organic semiconductor layer, and a hole extraction layer are sequentially formed on the first short-circuit prevention layer by a coating method. After applying these organic layers, a second groove that reaches the first short-circuit prevention layer is formed by laser scribing in the vicinity of several tens to 100 μm so as not to overlap the first groove. The width of the second groove is usually 50 to 1000 μm, particularly preferably 100 to 500 μm.

  Next, a second short-circuit prevention layer and an upper electrode are sequentially formed on the hole extraction layer. Here, after the second short-circuit prevention layer is formed, the second short-circuit prevention layer is continuously formed so as to form the upper electrode on the second short-circuit prevention layer without contacting the second object. The upper electrode is preferably formed. For example, NiO is used as the second short-circuit prevention layer, and Ag is used as the upper electrode.

Thereafter, the stacked body is laser-scribed to form a third groove reaching the lower electrode and divided into unit cells. Thereafter, a collector wire for taking out the generated electricity is attached to the upper electrode, and the entire organic thin-film solar battery cell is sealed to produce an organic thin-film solar battery module. The organic thin film solar cell element can be sealed by a known method.
In this embodiment, at least the organic semiconductor layer is manufactured by a roll-to-roll method, and it is preferable to form a layer other than the lower electrode and the first short-circuit preventing layer by roll-to-roll.
In addition, a short circuit prevention layer is not an essential layer for manufacturing an organic thin-film solar cell element.

2 Thin film solar cell module The thin film solar cell module which concerns on this embodiment installs a current collection line in a thin film solar cell element, and seals it. A solar cell module including a solar cell element according to an embodiment of the present invention will be described with reference to FIG. 2 using an organic thin film solar cell module including an organic thin film solar cell element as a representative example. FIG. 2 is a diagram schematically showing the configuration of the organic thin film solar cell module. As shown in FIG. 2, the organic thin-film solar cell module 14 of this embodiment includes a weather-resistant protective film 1, an ultraviolet cut film 2, a gas barrier film 3, a getter material film 4, a sealing material 5, and an organic material. The thin film solar cell element 6, the sealing material 7, the getter material film 8, the gas barrier film 9, and the back sheet 10 are provided in this order. And light is irradiated from the side (downward in the figure) where the weather-resistant protective film 1 was formed, and the organic thin-film solar cell element 6 generates electric power. Electricity generated by the organic thin-film solar cell element 6 is taken out by a collector line 15 connected to the organic thin-film solar cell element. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. Good.

2.1 Weatherproof protective film 1
The weather-resistant protective film 1 is a film that protects the organic thin-film solar cell element 6 from weather changes. By covering the organic thin-film solar cell element 6 with the weather-resistant protective film 1, the organic thin-film solar cell element 6 and the like are protected from weather changes and the power generation capacity is kept high. Since the weather-resistant protective film 1 is located on the outermost layer of the organic thin-film solar cell module 14, the weather-resistant protective film 1 of the organic thin-film solar cell module such as weather resistance, heat resistance, transparency, water repellency, contamination resistance and / or mechanical strength is used. It is preferable to have properties suitable for a surface coating material and to maintain it for a long period of time in outdoor exposure.

  Moreover, it is preferable that the weather-resistant protective film 1 transmits visible light from a viewpoint which does not prevent the light absorption of the organic thin-film solar cell element 6. For example, the transmittance of visible light (wavelength 360 to 830 nm) is preferably 80% or more, and the upper limit is not limited. Furthermore, since the organic thin film solar cell module 14 is often heated by receiving light, it is preferable that the weather-resistant protective film 1 also has heat resistance. From this viewpoint, the melting point of the constituent material of the weather-resistant protective film 1 is usually 100 ° C. or higher and 350 ° C. or lower.

  The material which comprises the weather-resistant protective film 1 is arbitrary if the organic thin-film solar cell element 6 can be protected from a weather change. Examples of the material include polyethylene resin, polypropylene resin, cyclic polyolefin resin, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, polyvinyl chloride resin, fluorine resin, polyethylene terephthalate, polyethylene Examples thereof include polyester resins such as naphthalate, phenol resins, polyacrylic resins, polyamide resins such as various nylons, polyimide resins, polyamide-imide resins, polyurethane resins, cellulose resins, silicon resins, and polycarbonate resins.

In addition, the weather-resistant protective film 1 may be formed with 1 type of material, and may be formed with 2 or more types of materials. Moreover, although the weather-resistant protective film 1 may be formed with the single layer film, the laminated | multilayer film provided with the film of two or more layers may be sufficient as it.
The thickness of the weather-resistant protective film 1 is not particularly defined, but is usually 10 μm or more and 200 μm or less.
Moreover, you may perform surface treatment, such as a corona treatment and / or a plasma treatment, for the weather-resistant protective film 1 in order to improve the adhesiveness with another film.

  It is preferable to provide the weatherproof protective film 1 on the outer side of the organic thin film solar cell module 14 as much as possible. This is because more of the constituent members of the organic thin film solar cell module 14 can be protected.

2.2 UV cut film 2
The ultraviolet cut film 2 is a film that prevents the transmission of ultraviolet rays. The organic thin film solar cell element 6 and, if necessary, a gas barrier film are provided by providing the ultraviolet cut film 2 on the light receiving portion of the organic thin film solar cell module 14 and covering the light receiving surface 6a of the organic thin film solar cell element 6 with the ultraviolet cut film 2. 3, 9 etc. are protected from ultraviolet rays, and the power generation capacity can be kept high.

  The degree of the ability to suppress the transmission of ultraviolet rays required for the ultraviolet cut film 2 is preferably such that the transmittance of ultraviolet rays (for example, wavelength of 300 nm) is 50% or less, and there is no limit on the lower limit. Moreover, it is preferable that the ultraviolet cut film 2 transmits visible light from the viewpoint of not preventing the light absorption of the organic thin film solar cell element 6. For example, the transmittance of visible light (wavelength 360 to 830 nm) is preferably 80% or more, and the upper limit is not limited.

Furthermore, since the organic thin film solar cell module 14 is often heated by receiving light, the ultraviolet cut film 2 preferably has resistance to heat. From this viewpoint, the melting point of the constituent material of the ultraviolet cut film 2 is usually 100 ° C. or higher and 350 ° C. or lower.
Moreover, it is preferable that the ultraviolet cut film 2 is high in flexibility, has good adhesion to an adjacent film, and can cut water vapor and oxygen.

  The material which comprises the ultraviolet cut film 2 is arbitrary if the intensity | strength of an ultraviolet-ray can be weakened. Examples of the material include films formed by blending an ultraviolet absorber with an epoxy, acrylic, urethane, or ester resin. Further, a film in which a layer of an ultraviolet absorbent dispersed or dissolved in a resin (hereinafter referred to as “ultraviolet absorbing layer” as appropriate) is formed on a base film may be used.

Examples of the ultraviolet absorber that can be used include salicylic acid-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based ones. In addition, a ultraviolet absorber may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio. As described above, a film in which an ultraviolet absorbing layer is formed on a base film can also be used as the ultraviolet absorbing film. Such a film can be produced, for example, by applying a coating solution containing an ultraviolet absorber on a substrate film and drying it.
Although the material of a base film is not specifically limited, For example, polyester is mentioned at the point from which the balance of heat resistance and a softness | flexibility is obtained.

  Examples of specific products of the ultraviolet cut film 2 include cut ace (MKV Plastic Co., Ltd.). In addition, the ultraviolet cut film 2 may be formed with 1 type of material, and may be formed with 2 or more types of materials.

  Further, the ultraviolet cut film 2 may be formed of a single layer film, but may be a laminated film including two or more layers. The thickness of the ultraviolet cut film 2 is not particularly limited, but is usually 5 μm or more and 200 μm or less.

  Although the ultraviolet cut film 2 should just be provided in the position which covers at least one part of the light-receiving surface 6a of the organic thin film solar cell element 6, Preferably it is provided in the position which covers all the light-receiving surfaces 6a of the organic thin film solar cell element 6. FIG. However, the ultraviolet cut film 2 may be provided at a position other than the position covering the light receiving surface 6 a of the organic thin film solar cell element 6.

2.3 Gas barrier film 3
The gas barrier film 3 is a film that prevents permeation of water and oxygen. By covering the organic thin-film solar cell element 6 with the gas barrier film 3, the organic thin-film solar cell element 6 can be protected from water and oxygen, and the power generation capacity can be kept high.

The degree of moisture resistance required for the gas barrier film 3 varies depending on the type of the organic thin-film solar cell element 6 and the like, but the water vapor transmission rate per unit area (1 m ² ) is usually 1 ×.
It is preferably 10 ⁻¹ g / m ² / day or less, and the lower limit is not limited.

The degree of oxygen permeability required for the gas barrier film 3 varies depending on the type of the organic thin film solar cell element 6 and the like, but the oxygen permeability per unit area (1 m ² ) is usually 1 ×.
It is preferably 10 ⁻¹ cc / m ² / day / atm or less, and the lower limit is not limited.

  Moreover, it is preferable that the gas barrier film 3 transmits visible light from the viewpoint of not preventing the organic thin film solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, and there is no upper limit.

  Furthermore, since the organic thin film solar cell module 14 is often heated by receiving light, the gas barrier film 3 preferably has heat resistance. From this viewpoint, the melting point of the constituent material of the gas barrier film 3 is usually 100 ° C. or higher and 350 ° C. or lower.

The specific structure of the gas barrier film 3 is arbitrary as long as the organic thin-film solar cell element 6 can be protected from water. However, since the manufacturing cost increases as the amount of water vapor or oxygen that can permeate the gas barrier film 3 increases, it is preferable to use an appropriate film considering these points comprehensively.

Particularly suitable gas barrier film 3 includes, for example, a film obtained by vacuum-depositing SiO _x on a base film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).

In addition, the gas barrier film 3 may be formed with 1 type of material, and may be formed with 2 or more types of materials. The gas barrier film 3 may be formed of a single layer film, but may be a laminated film including two or more layers.
The thickness of the gas barrier film 3 is not particularly defined, but is usually 5 μm or more and 200 μm or less.

  As long as the gas barrier film 3 can cover the organic thin-film solar cell element 6 and protect it from moisture and oxygen, the formation position is not limited, but the front surface of the organic thin-film solar cell element 6 (surface on the light-receiving surface side; lower side in FIG. 2). And the back surface (the surface opposite to the light receiving surface; the upper surface in FIG. 2). This is because the organic thin-film solar cell module 14 often has a front surface and a back surface formed in a larger area than the other surfaces. In this embodiment, the gas barrier film 3 covers the front surface of the organic thin film solar cell element 6, and a gas barrier film 9 described later covers the back surface of the organic thin film solar cell element 6. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. Good.

2.4 Getter material film 4
The getter material film 4 is a film that absorbs moisture and / or oxygen. By covering the organic thin film solar cell element 6 with the getter material film 4, the organic thin film solar cell element 6 and the like are protected from moisture and / or oxygen, and the power generation capacity is kept high. Here, unlike the gas barrier film 3 as described above, the getter material film 4 does not prevent moisture permeation but absorbs moisture. By using a film that absorbs moisture, the getter material film 4 captures moisture that slightly enters the space formed by the gas barrier films 3 and 9 when the organic thin film solar cell element 6 is covered with the gas barrier film 3 or the like. Thus, the influence of moisture on the organic thin film solar cell element 6 can be eliminated.

The degree of water absorption capacity of the getter material film 4 is usually 0.1 mg / cm ² or more,
Although there is no restriction | limiting in an upper limit, Usually, it is 10 mg / cm < ² > or less. Further, when the organic thin film solar cell element 6 is covered with the gas barrier films 3 and 9 or the like by the getter material film 4 absorbing oxygen, oxygen that slightly enters the space formed by the gas barrier films 3 and 9 is absorbed. The getter material film 4 can capture and eliminate the influence of oxygen on the organic thin film solar cell element 6.

  Furthermore, it is preferable that the getter material film 4 transmits visible light from the viewpoint of not hindering the light absorption of the organic thin film solar cell element 6. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, and there is no upper limit.

  Furthermore, since the organic thin-film solar cell module 14 is often heated by receiving light, the getter material film 4 preferably has resistance to heat. From this viewpoint, the melting point of the constituent material of the getter material film 4 is usually 100 ° C. or higher and 350 ° C. or lower.

The material constituting the getter material film 4 is arbitrary as long as it can absorb moisture and / or oxygen. Examples of the material include alkali metal, alkaline earth metal or alkaline earth metal oxides; alkali metal or alkaline earth metal hydroxides; silica gel, zeolitic compounds, magnesium sulfate. And sulfates such as sodium sulfate and nickel sulfate; and organometallic compounds such as aluminum metal complexes and aluminum oxide octylates. Specifically, examples of the alkaline earth metal include Ca, Sr, and Ba. Examples of the alkaline earth metal oxide include CaO, SrO, and BaO. In addition, Zr-Al-BaO and aluminum metal complexes are also included. Specific product names include, for example, OleDry (Futaba Electronics).

  Examples of the substance that absorbs oxygen include activated carbon, silica gel, activated alumina, molecular sieve, magnesium oxide, and iron oxide. In addition, Fe, Mn, Zn, and inorganic salts such as sulfates, chlorides, and nitrates of these metals are also included.

In addition, the getter material film 4 may be formed of one type of material or may be formed of two or more types of materials. The getter material film 4 may be formed of a single layer film, but may be a laminated film including two or more layers.
The thickness of the getter material film 4 is not particularly specified, but is usually 5 μm or more and 200 μm or less.

  The getter material film 4 is not limited in its formation position as long as it is in the space formed by the gas barrier films 3 and 9, but the front surface of the organic thin-film solar cell element 6 (the surface on the light receiving surface side. Surface) and the back surface (the surface opposite to the light receiving surface; the upper surface in FIG. 2) is preferably covered. This is because the organic thin film solar cell module 14 often has a front surface and a back surface formed in a larger area than the other surfaces, and therefore moisture and oxygen tend to enter through these surfaces. From this viewpoint, the getter material film 4 is preferably provided between the gas barrier film 3 and the organic thin film solar cell element 6. In this embodiment, the getter material film 4 covers the front surface of the organic thin film solar cell element 6, the getter material film 8 described later covers the back surface of the organic thin film solar cell element 6, and the getter material films 4 and 8 are respectively organic thin film solar cells. It is located between the element 6 and the gas barrier films 3 and 9. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. Good.

2.5 Sealant 5
The sealing material 5 is a film that reinforces the organic thin film solar cell element 6. Since the organic thin film solar cell element 6 is thin, the strength is usually weak, and thus the strength of the organic thin film solar cell module tends to be weak. However, the strength can be maintained high by the sealing material 5.

  Moreover, it is preferable that the sealing material 5 has high strength from the viewpoint of maintaining the strength of the organic thin-film solar cell module 14. The specific strength is related to the strength of the weatherproof protective film 1 other than the sealing material 5 and the strength of the back sheet 10 and is generally difficult to define, but the entire organic thin-film solar cell module 14 has good bending workability. It is desirable to have strength that does not cause peeling of the bent portion.

Moreover, it is preferable that the sealing material 5 permeate | transmits visible light from a viewpoint which does not prevent the light absorption of the organic thin film solar cell element 6. FIG. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, and there is no upper limit.
The thickness of the sealing material 5 is not particularly specified, but is usually 2 μm or more and 700 μm or less.

  The T-type peel adhesion strength of the sealing material 5 to the substrate is usually 1 N / inch or more and usually 2000 N / inch or less. It is preferable that the T-type peel adhesive strength is 1 N / inch or more in terms of ensuring the long-term durability of the module. It is preferable that the T-type peel adhesive strength is 2000 N / inch or less in that the base material, the barrier film, and the adhesive can be separated and discarded when the solar cell is discarded. The T-type peel adhesion strength is measured by a method according to JIS K6854.

  The constituent material of the sealing material 5 is not particularly limited as long as it has the above characteristics, but sealing of organic / inorganic solar cells, sealing of organic / inorganic LED elements, sealing of electronic circuit boards, etc. In general, a sealing material generally used can be used.

  Specifically, a thermosetting resin composition or a thermoplastic resin composition and an active energy ray curable resin composition can be mentioned. The active energy ray-curable resin composition is, for example, a resin that is cured by ultraviolet rays, visible light, electron beams, or the like. More specifically, an ethylene-vinyl acetate copolymer (EVA) resin composition, a hydrocarbon resin composition, an epoxy resin composition, a polyester resin composition, an acrylic resin composition, and a urethane resin composition. Or a silicon-based resin composition, etc., depending on the main chain, branched chain, terminal chemical modification of each polymer, adjustment of molecular weight, additives, etc., thermosetting, thermoplastic and active energy ray curable, etc. The characteristics are expressed.

  Moreover, since the organic thin-film solar cell module 14 is often heated by receiving light, it is preferable that the sealing material 5 also has heat resistance. From this viewpoint, the melting point of the constituent material of the sealing material 5 is usually 100 ° C. or higher and 350 ° C. or lower.

The density of the constituent material for sealing material in the sealing material 5 is preferably 0.80 g / cm ³ or more, and there is no upper limit. The measurement and evaluation of density can be performed by a method based on JIS K7112.

  Although there is no restriction | limiting in the position which provides the sealing material 5, Usually, it provides so that the organic thin-film solar cell element 6 may be inserted | pinched. It is for protecting the organic thin film solar cell element 6 reliably. In this embodiment, the sealing material 5 and the sealing material 7 are provided on the front surface and the back surface of the organic thin film solar cell element 6, respectively.

2.6 Organic thin film solar cell element 6
The organic thin film solar cell element 6 is the same as the organic thin film solar cell element 107 described above. That is, the organic thin film solar cell module 14 can be manufactured using the organic thin film solar cell element 107.

  Although only one organic thin film solar cell element 6 may be provided for each organic thin film solar cell module 14, two or more organic thin film solar cell elements 6 are usually provided. What is necessary is just to set the number of the specific organic thin film solar cell elements 6 arbitrarily. When a plurality of organic thin film solar cell elements 6 are provided, the organic thin film solar cell elements 6 are often arranged in an array.

  When a plurality of organic thin film solar cell elements 6 are provided, the organic thin film solar cell elements 6 are usually electrically connected to each other, and electricity generated from the group of connected organic thin film solar cell elements 6 is a terminal (not shown). In this case, the solar cell elements are usually connected in series in order to increase the voltage.

Thus, when connecting the organic thin film solar cell elements 6 to each other, it is preferable that the distance between the organic thin film solar cell elements 6 is small, and as a result, between the organic thin film solar cell element 6 and the organic thin film solar cell element 6. The gap is preferably narrow. This is because the light receiving area of the organic thin film solar cell element 6 is widened to increase the amount of light received, and the amount of power generated by the organic thin film solar cell module 14 is increased.

2.7 Sealant 7
The sealing material 7 is a film similar to the sealing material 5 described above, and the same material as the sealing material 7 can be used in the same manner except that the arrangement position is different. Moreover, since the constituent member on the back side of the solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

2.8 Getter material film 8
The getter material film 8 is the same film as the getter material film 4 described above, and the same material as the getter material film 4 can be used as necessary, except for the arrangement position. Moreover, since the constituent member on the back side of the organic thin film solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

2.9 Gas barrier film 9
The gas barrier film 9 is the same film as the gas barrier film 3 described above, and the same material as the gas barrier film 9 can be used as necessary except that the arrangement position is different. Moreover, since the constituent member on the back side of the organic thin film solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

2.10 Backsheet 10
The back sheet 10 is the same film as the weather-resistant protective film 1 described above, and the same material as the weather-resistant protective film 1 can be used in the same manner except that the arrangement position is different. In addition, if the back sheet 10 is difficult to permeate water and oxygen, the back sheet 10 can also function as a gas barrier layer. Moreover, since the constituent member on the back side of the organic thin film solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

2.11 Current collector 15
Both ends of the current collector 15 are outside the sealing structure. That is, the electric wire for taking out electricity from the both ends can be connected.
As a material for the current collector, metals, alloys, and the like are often used, and among them, it is preferable to use copper, aluminum, silver, gold, nickel, or the like having low resistivity. Among these, 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. As the shape of the current collecting wire, there are a rectangular wire, foil, flat plate, and wire shape, but for reasons such as securing a bonding area, it is preferable to use a flat wire, foil, or flat plate shape.
In the present invention, the “foil” refers to one having a thickness of less than 100 μm, and the “plate” refers to one having a thickness of 100 μm or more. Further, the “flat wire” refers to a wire whose cross section is rolled to make the cross section into a quadrangle.

The current collector is not particularly limited as long as it has conductivity, but preferably has a lower resistance value than the upper electrode and lower electrode to be connected. In particular, by increasing the thickness of the upper electrode and lower electrode, resistance is increased. 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. Further, it is preferably 2 mm or less, more preferably 1 mm or less, and particularly preferably 300 μm or less. If the thickness is thinner than the above range, the resistance value of the current collector increases, and the generated power cannot be taken out efficiently. Further, if the thickness is larger than the above range, there is a risk that the solar cell module will increase in weight and the flexibility will decrease, the surface of the module will easily become uneven, and the production cost will increase. is there.

  The width of the current collector is preferably 0.5 mm or more, more preferably 1 mm or more, and particularly preferably 2 mm or more. Moreover, it is preferable that the width | variety of a current collection line is 50 mm or less, More preferably, it is 20 mm or less, Most preferably, it is 10 mm or less. If the width of the current collecting line is narrower than the above range, the resistance value of the current collecting line increases, and the generated power cannot be efficiently taken out. In addition, the mechanical strength of the current collector decreases, which may cause breakage and the like. Moreover, when the width | variety of a current collection line is wider than the said range, the aperture ratio in the whole module will reduce, and there exists a possibility of leading to the fall of the power generation amount of a module.

2.12 Dimensions, etc. The organic thin film solar cell module 14 according to this embodiment is usually a thin film member. Thus, by forming the organic thin film solar cell module 14 as a film-like member, the organic thin film solar cell module 14 can be easily installed in a building material, an automobile, an interior, or the like. The organic thin-film solar cell module 14 is light and difficult to break, and thus a highly safe solar cell can be obtained and can be applied to a curved surface, so that it can be used for more applications. Since it is thin and light, it is preferable in terms of distribution such as transportation and storage. Furthermore, since it is in the form of a film, it can be manufactured in a roll-to-roll manner, and a significant cost cut can be achieved.
Although there is no restriction | limiting in the specific dimension of the organic thin film solar cell module 14, The thickness is usually 300 micrometers or more and 3000 micrometers or less.
Moreover, it is also preferable to make a roll-shaped thin film solar cell module using a roll-shaped thin film solar cell element. The roll shape is synonymous with the description in the thin film solar cell element described above.
The length of the roll-shaped thin film solar cell module is usually 1 m or more, preferably 5 m or more, more preferably 10 m or more, and further preferably 100 m or more, and the upper limit is not particularly limited, but is usually 10,000 m or less, preferably 5000 m or less, More preferably, it is 1000 m or less, More preferably, it is 500 m or less.

2.13 Manufacturing Method There is no limitation on the manufacturing method of the organic thin film solar cell module 14 according to this embodiment. For example, as a solar cell manufacturing method in the form of FIG. The method of performing a lamination sealing process after installing a collector wire is mentioned. Although the installation position of the current collector is not limited, usually, two current collectors are installed so as to be connected to the cells at both ends of the organic thin film solar cell element. Further, in addition to the two current collectors, the potential extracted from the organic thin film solar cell module can be arbitrarily set by connecting to cells other than both ends of the organic thin film solar cell. In the present invention, the fact that both ends of the current collector are exposed outside the sealing structure means that the two current collectors are electrically connected, for example, by being connected to the same electrode of the solar battery cell. In this embodiment, both ends of the collected current collector are exposed outside the sealing structure.

  The laminate production shown in FIG. 2 can be performed using a known technique. The method of the laminate sealing step is not particularly limited as long as the effects of the present invention are not impaired, but for example, wet lamination, dry lamination, hot melt lamination, extrusion lamination, coextrusion molding lamination, extrusion coating, photocuring adhesive Laminate, thermal laminate, etc. are mentioned. Among them, a laminating method using a photo-curing adhesive having a proven record in organic EL device sealing, a hot melt laminate or a thermal laminate having a proven record in solar cells is preferable, and a hot melt laminate or a thermal laminate is a sheet-like sealing material. It is more preferable at the point which can be used.

The heating temperature in the laminate sealing step is usually 130 ° C or higher, preferably 140 ° C or higher, and is usually 180 ° C or lower, preferably 170 ° C or lower. The heating time in the laminate sealing step is usually 10 minutes or longer, preferably 20 minutes or longer, and is usually 100 minutes or shorter, preferably 90 minutes or shorter. The pressure in the laminate sealing step is usually 0.001 MPa or more, preferably 0.01 MPa or more, and usually 0.2 MPa or less, preferably 0.1 MPa or less. By setting the pressure within this range, sealing can be performed reliably, and the reduction of the film thickness due to the protrusion of the sealing materials 5 and 7 from the end portion and overpressurization can be suppressed, thereby ensuring dimensional stability. In addition, what connected two or more organic thin film solar cell elements 6 in series or in parallel can be manufactured similarly to the above.

2.14 Application There is no limitation on the application of the organic thin-film solar cell module 14 according to the embodiment of the present invention, and it can be used for any application. Examples of fields to which organic thin-film solar cell modules are applied include building material solar cells, automotive solar cells, interior solar cells, railway solar cells, marine solar cells, airplane solar cells, and spacecraft solar cells. , Solar cells for home appliances, solar cells for mobile phones, solar cells for toys, and the like.

  The organic thin film solar cell module may be used as it is, or an organic thin film solar cell module may be installed on a substrate and used as an organic thin film solar cell panel. For example, an organic thin film solar cell panel provided with the organic thin film solar cell module 14 on a base material may be prepared and used at a place of use. That is, an organic thin film solar cell panel can be manufactured using the organic thin film solar cell module 14. If a specific example is given, when using the board | plate material for building materials as a base material, a solar cell panel can be produced as an organic thin film solar cell panel by providing the organic thin film solar cell module 14 on the surface of this board | plate material.

  The base material is a support member that supports the organic thin film solar cell module 14. Examples of the material for forming the substrate include inorganic materials such as glass, sapphire and titania; polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, fluororesin , Vinyl chloride, polyethylene, cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate and polynorbornene, etc .; paper materials such as paper and synthetic paper; metals such as stainless steel, titanium and aluminum; stainless steel And composite materials such as those obtained by coating or laminating a surface of a metal such as titanium and aluminum to give insulation.

  In addition, 1 type may be used for the material of a base material, and 2 or more types may be used together by arbitrary combinations and a ratio. Moreover, carbon fiber may be included in these organic materials or paper materials to reinforce the mechanical strength. Examples of the substrate include Alpolic (registered trademark; manufactured by Mitsubishi Plastics) and the like.

  Although there is no restriction | limiting in the shape of a base material, Usually, a board | plate material is used. Moreover, what is necessary is just to set the material of a base material, a dimension, etc. arbitrarily according to the use environment. This solar cell panel can be installed on the outer wall of a building.

2.15 Installation Example of Organic Thin Film Solar Cell Array Hereinafter, an installation example of an organic thin film solar cell array in which a plurality of organic thin film solar cell modules according to a specific embodiment of the present invention are connected will be described with reference to the drawings.
In the organic thin film solar cell according to this embodiment, as shown in FIG. 3, both ends of the collector line 15 installed in the organic thin film solar cell module 14 are exposed outside the sealing structure. FIG. 3 is a view of the organic thin film solar cell module as viewed from above. The organic thin film solar cell module includes an organic thin film solar cell element 6 and a solar cell non-installation portion 16. The organic thin film solar cell module 16 is formed by sealing the organic thin film solar cell element 6, and an encapsulant layer, a protective layer, and the like are provided on the upper and lower portions of the organic thin film solar cell element 6 and the solar cell non-installation portion 16. Laminated and sealed by thermal lamination. In this specification, the layer laminated | stacked on the organic thin film solar cell element 6 and the layer laminated | stacked on the solar cell non-installation part 16 are called sealing structure.
In this embodiment, both ends of the current collector are exposed outside the sealing structure. There are various effects due to the structure in which both ends of the current collector are exposed outside the sealing structure, but wiring should not be complicated, especially when multiple organic thin film solar cells are connected to form an organic thin film solar cell array. Will be described with reference to FIGS.

  FIG. 5 is a schematic diagram showing an organic thin film solar cell array (a) in which a plurality of conventional organic thin film solar cell modules are connected in parallel and an organic thin film solar cell array (b) in which a plurality of organic thin film solar cell modules are connected in series. That is, in the conventional organic thin film solar cell module, only one end of the current collecting line is exposed from the sealing structure, and the other end remains sealed. Therefore, for example, as shown in (a), in order to connect a plurality of organic thin-film solar cell modules in parallel, a collective wiring for connecting the current collectors from each module separately from the current collector 15 arranged in each module. It is necessary to prepare 15 '. As a result, when one end of the current collecting line exposed from the sealing structure is connected to take out the generated electricity, the wiring becomes very complicated.

On the other hand, FIG. 4 shows an organic thin film solar cell array (a) in which a plurality of organic thin film solar cell modules according to this embodiment are connected in parallel, and an organic thin film solar cell array (b) and (c) in which a plurality of organic thin film solar cell modules are connected in series. It is a schematic diagram. That is, since the organic thin-film solar cell module according to the present embodiment exposes both ends of the current collecting line from the sealing structure, the degree of freedom of wiring connection is increased and a simple wiring structure can be achieved.
Thus, by using the organic thin film solar cell module according to the present embodiment, the entire wiring can be shortened, so that the voltage drop at the time of electricity extraction is suppressed, and the electrical resistance in the entire array is reduced, There are advantageous effects such as high PCE.

Such an effect of the present invention is remarkably exhibited particularly when the thin film solar cell module is an organic thin film solar cell module.
When the thin film solar cell is amorphous silicon, the amorphous silicon solar cell has some resistance to water and oxygen. Therefore, the solar cell array can be manufactured by connecting the current collector in the atmosphere before sealing the solar cell and further sealing the whole after connecting the current collectors of the plurality of solar cells. On the other hand, when the thin-film solar cell is an organic thin-film solar cell, it is not overwhelmingly resistant to water and oxygen as compared with the amorphous silicon solar cell, and the performance is significantly reduced when it is placed in the atmosphere. Therefore, in the case of organic thin film solar cells, it is necessary to perform the work in a special environment such as a dry room in order to connect the current collector before sealing the individual organic thin film solar cells. The degree was low. Therefore, it is necessary to manufacture an organic thin-film solar cell array by connecting organic thin-film solar cell modules after sealing and producing an organic thin-film solar cell module after installing a collector wire on the organic thin-film solar cell. there were.
At this time, in order to take out electricity from the organic thin-film solar cell module, it is sufficient that there are two connection points by the current collector, so that only one of the current collectors is exposed from the sealing structure. However, the present inventors have found that conventional organic thin film solar cell modules cause various problems during the manufacture of the array, and the thin film solar cell module having a new structure for solving the problems, ie, the book The inventors have arrived at a thin film solar cell module according to the invention.

The present invention also provides another aspect.
That is, a method for producing an organic thin film solar cell, comprising: a laminating step for laminating constituent members of an organic thin film solar cell including a current collecting line; and a sealing step for sealing the laminated body. It is a manufacturing method arrange | positioned so that the both ends of an electric wire may be exposed outside a sealing structure.
A step of connecting a plurality of organic thin-film solar cell modules including a current collector and having both ends of the current collector exposed to the outside of the sealing structure; and a step of sealing the plurality of connected organic thin-film solar cell modules; Is a method for manufacturing an organic thin film solar cell array.

DESCRIPTION OF SYMBOLS 101 Lower electrode 102 Electron taking-out layer 103 Active layer 104 Hole taking-out layer 105 Upper electrode 106 Solar cell element board | substrate 107 Organic thin film solar cell element 1 Weatherproof protective film 2 UV cut film 3,9 Gas barrier film 4,8 Getter material film 5 , 7 Sealing material 6 Organic thin film solar cell element 10 Back sheet 14 Organic thin film solar cell module 15 Current collecting wire 15 ′ Current collecting wire 16 Solar electrode non-installation portion 17 Terminal boxes 20a, 20b, 20c Organic thin film solar cell array 20a ′, 20b 'organic thin film solar cell array

Claims (4)

A thin-film solar cell module encapsulating a thin-film solar cell element on which two or more current collectors are installed,
Both ends of at least two current collectors of the two or more current collectors are exposed outside the sealing structure,
Thin film solar cell module.   The thin film solar cell module according to claim 1, wherein the thin film solar cell element is a thin film solar cell element in which a plurality of solar cells are connected monolithically.   The thin film solar cell module according to claim 1 or 2, wherein the thin film solar cell element is an organic thin film solar cell element.   The thin film solar cell array formed by connecting two or more thin film solar cell modules of any one of Claims 1-3.