JPH1197727A - Solar cell module and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make clear the deformable region of a photovoltaic element by pulling and deforming at least one portion of a flexible substrate in horizontal direction of a substrate material with the amount of distortion that is less than the reduction critical value of a fill factor and by deforming and machining the photovoltaic element. SOLUTION: The fill factor(FF) decreases from a point with certain amount of distortion and the reduction in FF represents a gentle curve, so that two tangent lines are drawn and the value of their intersection is called an FF reduction critical value. By using a material with a plastic deformation region at a value less than the FF reduction critical value (0.7% in the case of a-Si:H) a a flexible substrate, a photovoltaic element 101 is deformed by deforming the substrate at a value less than the FF reduction critical value. After forming a plate-shaped solar cell module with a reinforcing material 107 bonded is formed, it is bent in a stair shape at the middle of the photovoltaic element 101. Locations where a distortion occurs in the machining are step-shaped crest and trough parts and the greatest distortion occurs at the crest parts, thus making clear the deformable region of the photovoltaic element 101.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell module and a method of manufacturing the same, and more particularly, to a variety of highly reliable solar cell modules in which a region including a photovoltaic element is processed and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, awareness of protection of energy resources and environmental issues has been increasing worldwide. Above all, there is a deep concern about the depletion of petroleum and the like and the global warming phenomenon associated with CO2 emissions. Therefore, solar cell energy, which can directly convert solar energy into electric power and is clean energy, has been greatly expected.

The types of solar cells widely used at present include those using crystalline silicon and those using amorphous silicon.

[0004] In particular, an amorphous silicon solar cell in which silicon is deposited on a conductive metal substrate and a transparent conductive layer is formed thereon is cheaper and lighter than a solar cell using crystalline silicon, and has a high impact resistance. It is promising because of its richness and flexibility. Recently, it has been installed on roofs and walls of buildings, taking advantage of the characteristics of amorphous silicon solar cells, such as light weight, excellent impact resistance, and flexibility. In this case, the non-light-receiving surface side of the solar cell is used as a building material by bonding a reinforcing material via an adhesive. By bonding the reinforcing material in this manner, the mechanical strength of the solar cell module is increased, and warpage and distortion due to a temperature change can be prevented. In particular, installation on a roof is being actively performed because more sunlight can be taken in.
Conventionally, when using as a roof, the process procedure of mounting a frame on a solar cell, installing a gantry on the roof, and then installing a solar cell on it, was used. The obtained solar cell module can be directly installed as a roof material by bending a reinforcing material. As a result, the cost of raw materials can be significantly reduced and the number of work steps can be significantly reduced, so that an inexpensive solar cell module can be provided. In addition, a very lightweight solar cell can be provided because no frame or mount is required. That is, the solar cell can be treated as a metal roof that has recently attracted attention because of its excellent workability, light weight, and excellent earthquake resistance.

For example, a roofing-integrated solar cell module proposed in Japanese Patent Application Laid-Open No. 07-302924 is processed in the same manner as a normal roof, so that it has excellent workability, and is conventionally used for processing. Can be used as is and handling is ready. However, this solar cell module
The photovoltaic element is located on the flat part of the flat roofing material, and the photovoltaic element has a structure that is not deformed at all.

[0006] However, recently, individual originality tends to be emphasized, and this is no exception in building materials and solar cells. In order to produce solar cells or building materials with a variety of shapes that meet various needs, instead of keeping the photovoltaic element flat at all times, it is necessary to cover all areas including the photovoltaic element. Workability must be ensured.

[0007] As one example corresponding to such diversity, Japanese Patent Application Laid-Open Nos. Hei 8-222752, Hei 8-222753, and Japanese Patent Publication No. 6-5769
Describes a corrugated solar cell module. In each case, the photovoltaic elements are arranged in a wave shape in order to improve the light use efficiency, and the manufacturing method is a procedure in which the photovoltaic elements are attached to a steel plate processed on a corrugated sheet with an adhesive. I have.

[0008] In addition, studies on the relationship between the a-Si: H layer and the amount of strain have been reported.

For example, Appl. Phys. Lett. 54 (17), 1989, p.
678-1680, "Electrical properties of hydrogenated amo
rphous silicon layers on polymer film substrate un
In "dertensile stress", a on a PET substrate (100 μm thick)
A-Si: H single film (0.5μm thickness, mainly I-type a-Si: H) laminated
-It has been reported that the resistance change in the dark state by pulling the -Si: H layer. The details of this report are as follows.

When the a-Si: H layer is pulled, the resistance gradually increases due to the piezo effect up to 0.7% strain (reversible). From 0.7% strain, the weak Si-Si bond is broken, so Resistance rises (irreversible). However, the a-Si: H layer, which has increased resistance by being strained by 0.7% or more, is restored by annealing at 150 ° C. for 1 hour.

Also, J. Appl. Phys. 66 (1), 1989, p. 308-31
1, "Effect of mechanical strain onelectrical charac
teristics of hydrogenated amorphous silicon juncti
Ons "reports on the piezo effect of a-Si: H with a pin junction. The details of this report are as follows.

When a-Si: H having a pin junction is strained in parallel with the pin junction, the current decreases by 8% in both the forward and reverse directions under a tensile stress of 7500 με (dark state). The current increases by 8% under a compressive stress of 7500 με.

On the other hand, amorphous silicon solar cells
Generally, in order to make use of its flexibility and make a lightweight solar cell, a coating using a fluorine film on the outermost surface and various organic polymer resins as a filler inside the film has been performed. However, when the surface is covered with a film, it is less susceptible to external impact and damage (scratch resistance) than when covered with glass. In order to solve these drawbacks, a method has been devised in which a filler is impregnated with a fibrous inorganic compound such as a glass fiber nonwoven fabric to secure the strength on the light receiving surface side.

FIG. 8 is a conventional example showing a coating structure of such a solar cell module. In FIG. 8, 803 is a fluoride polymer thin film layer, 802 is a transparent organic polymer resin,
801 is a photovoltaic element, 804 is an insulating film, 805
Is a reinforcing plate. More specifically, the fluoride polymer thin film layer 803 is a fluororesin film such as an ETFE (ethylene-tetrafluoroethylene copolymer) film and a PVF (polyvinyl fluoride) film, and the transparent organic polymer resin 802 is EVA. (Ethylene-vinyl acetate copolymer), butyral resin and the like. Insulating film 804
Is a nylon film, PET (polyester) film,
An organic resin film such as an aluminum laminate tedlar film. The reinforcing plate 805 is made of an insulated metal such as a painted zinc steel plate, carbon fiber, FRP (glass fiber reinforced plastic), or the like.

[0015]

However, Japanese Patent Application Laid-Open No. 07-302924, which is a flat solar cell module, is, of course, disclosed in Japanese Patent Application Laid-Open Nos.
For a corrugated solar cell module such as 5769, there is no description about specific stress applied to the photovoltaic element when the photovoltaic element is processed into a corrugated shape. That is, neither the displacement of the substrate, the displacement of the photovoltaic element nor the displacement of the solar cell module is described. No mention is made of the effects of stress or deformation and their reliability.

Appl.Phys.Lett. 54 (17), 1989, p.1678-168
0, "Electrical properties of hydrogenated amorphous
silicon layers on polymer film substrate under te
nsilestress "and J. Appl. Phys. 66 (1), 1989, p. 308
-311, "Effect of mechanicalstrain on electrical cha
racteristics of hydrogenated amorphous siliconjunc
In “Options”, there is no description or suggestion that the photovoltaic element is used in a distorted state or that the photovoltaic element is modularized in a distorted state. No reliability evaluations have been made on solar cell modules that have been lost.

Since these are not clear, it is refrained from producing a photovoltaic module having a photovoltaic element processed or stressed or deformed. Reliability must always be considered. Usually, many reliability tests have to be performed on one product (processed shape), so it takes a very long time to commercialize one product. That is, with such a method, commercialization at a speed corresponding to the needs of current solar cells and building materials that require a wide variety of products cannot be expected.

As described above, the following points need to be solved in order to produce various solar cell modules that are faster and more reliable. When processing a region including a photovoltaic element, a deformable displacement area of the photovoltaic element is clarified. Long-term reliability when the photovoltaic element is deformed is ensured.

[0019]

Means for Solving the Problems As a result of intensive research and development for solving the above problems, the present inventor has found that the following method is the best.

In a solar cell module having a photovoltaic element having at least one semiconductor photoactive layer on a flexible substrate, at least a portion of the flexible substrate is filled with a fill factor (hereinafter referred to as a fill factor) in a horizontal direction of the substrate material. The solar cell module is characterized in that the photovoltaic element is deformed by tensile deformation with a strain amount less than the critical value for lowering FF).

(Operation) The solar cell module based on the above-described configuration includes the following aspects and has remarkable effects.

In a solar cell module having a photovoltaic element having at least one semiconductor photoactive layer on a flexible substrate, at least a part of the flexible substrate is provided with a FF lowering critical value in a horizontal direction of the substrate material. By deforming the photovoltaic element by tensile deformation with less than the amount of distortion, (1) The deformable area of the photovoltaic element becomes clear, so the product development speed of a wide variety of solar cell modules is increased. Significantly improved. (2) The photovoltaic element can be processed freely without deteriorating the characteristics of the solar cell. (3) Since the photovoltaic element can be freely processed, a solar cell module excellent in aesthetics and design can be obtained. (4) The solar cell module after the forming process can also be a highly reliable solar cell module.

The tensile deformation is within a plastic deformation region of a reinforcing member provided on the non-light-receiving surface side of the flexible substrate or the photovoltaic element, and the strain of the photovoltaic element is less than a critical value for lowering FF. (5) Since the flexible substrate is plastically deformed, a photovoltaic element having the shape even after processing can be obtained.

The photovoltaic element has at least a light receiving surface side coated with an organic polymer resin. (6) A flexible solar cell that fully utilizes the flexibility of the photovoltaic element. It can be a module.

By providing a reinforcing material on the non-light-receiving surface side of the solar cell module, (7) a building material-integrated solar cell module can be obtained,
The workability of the solar cell module is improved.

By providing a transparent resin film layer on the outermost surface on the light-receiving surface side of the solar cell module, (8) a light-weight solar cell module can be obtained, which is excellent in earthquake resistance. (9) Since the solar cell module can have flexibility, design and workability are improved. (10) External contamination during long-term outdoor exposure can be prevented, and a decrease in the conversion efficiency of the solar cell module can be reduced.

Since the reinforcing member has a strain in the plastic deformation region, (11) the solar cell module can be formed into various shapes without using other members.

Since the plastic deformation region of the reinforcing material is only a portion not including the photovoltaic element on the light receiving surface side, (12) the amount of strain to the photovoltaic element is suppressed to a value not more than the critical value for lowering the FF, The solar cell module can be largely deformed to produce a wide variety of products.

(13) Since the photovoltaic element is formed by forming amorphous silicon on a flexible substrate, (13) since both the substrate and the semiconductor layer have flexibility, they are reinforced regardless of the presence or absence of the photovoltaic element. Since the material can be processed, various types of solar cell modules can be processed.

When the flexible substrate is a conductive substrate, (14) the flexible substrate can be treated as a negative pole of the photovoltaic element, so that the electrode can be easily taken out.

When the plastic deformation area of the conductive substrate is 0.2% or more, (15) plastic deformation is performed with a small amount of strain, so that the photovoltaic element can be easily processed without damaging the semiconductor photoactive layer. .

(16) Since the conductive substrate is made of stainless steel, it has high corrosion resistance. Therefore, even when the substrate is coated with a polymer resin, a highly reliable solar cell can be formed without corrosion or oxidation. It can be a module.

Since the flexible substrate is made of a resin film, (17) an inexpensive solar cell module can be obtained, and the solar cell module is excellent in workability because it does not hinder processing.

When the reinforcing material is a metal, (18) a solar cell module having excellent weather resistance and wear resistance can be obtained. In addition, since it is a flexible reinforcing material, workability is improved.

Since the solar cell module is a building material-integrated solar cell module, (19) compared to a conventional type in which a solar cell module is installed on a building material, a building material is unnecessary, and a low-cost solar cell module is provided. Become a module. (20) Furthermore, by installing it on the roof or wall of a building,
Since the installation location can be used effectively, power can be generated efficiently.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An experiment showing the relationship between the photovoltaic element of the present invention and the amount of distortion will be described in detail.

A typical photovoltaic element in the present invention is:
The structure is such that a back reflection layer, a semiconductor active layer, a transparent conductive layer, and a collecting electrode are laminated on a substrate. FIG. 2 shows a schematic configuration diagram as an example, in which 201 is a conductive substrate, 202 is a back reflection layer, 203 is a semiconductor photoactive layer, 204 is a transparent conductive layer, 205 is a current collecting electrode, 206 is an output terminal.

As the substrate, metal, resin, glass, ceramics, semiconductor bulk and the like are used. The surface may have fine irregularities. A structure in which light is incident from the substrate side using a transparent substrate may be employed.

However, in order to maximize the flexibility of amorphous silicon, it is desirable to use a flexible substrate. That is, it is desirable to use metal or resin. By forming the metal or resin into a long shape, it is possible to cope with continuous film formation. Examples of the material for the resin substrate include polyethylene terephthalate, polyethylene naphthalate, aromatic polyester, aromatic polyamide, polysulfonic acid, polyimide, polyarylate, and polyetheretherketone. In addition, it is more preferable that the substrate be a conductive substrate because the substrate can serve as a lower electrode at the same time as a substrate for the photovoltaic element. Examples of the material of the conductive substrate include silicon, tantalum, molybdenum, tungsten, stainless steel, aluminum, copper, titanium, carbon sheets, lead-plated steel sheets, resin films having a conductive layer formed thereon, and ceramics. On the conductive substrate 201, the back reflection layer 2
As 02, a metal layer, a metal oxide layer, or a metal layer and a metal oxide layer may be formed. These roles serve as a reflection layer that reflects light reaching the substrate and reuses the light in the semiconductor layer. Providing irregularities on these surfaces has the effect of extending the optical path length of the reflected light in the semiconductor layer and increasing the short-circuit current. For example, Ti,
Cr, Mo, W, Al, Ag, Ni, Cu, Au, etc. are used. For the metal oxide layer, for example, ZnO, TiO.
2, SnO2 or the like is used. Examples of a method for forming the metal layer and the metal oxide layer include a resistance heating evaporation method, an electron beam evaporation method, a sputtering method, plating, and printing.

The semiconductor photoactive layer 203 is a portion for performing photoelectric conversion, and specific materials include pn junction type polycrystalline silicon, pin junction type amorphous silicon, and Cu.
InSe2, CuInS2, GaAs, CdS / Cu2
S, CdS / CdTe, CdS / InP, CdTe / C
and compound semiconductors such as u2Te. As a method of forming the semiconductor photoactive layer, in the case of polycrystalline silicon, a sheet of molten silicon or heat treatment of amorphous silicon is used. In the case of amorphous silicon, a microwave plasma CVD method using silane gas as a raw material, a high frequency plasma CVD method Method, VHF plasma CVD method, in the case of compound semiconductor, ion plating, ion beam deposition, vacuum evaporation method, sputtering method, electrodeposition method and the like.

The transparent conductive layer 204 functions as an upper electrode of a solar cell. At the same time, diffuse reflection of incident light and reflected light is increased, and the optical path length in the semiconductor layer is extended. Further, it prevents the elements of the metal layer from diffusing or migrating into the semiconductor layer, thereby preventing the photovoltaic element from shunting. Further, by having an appropriate resistance, a short circuit due to a defect such as a pinhole in the semiconductor layer is prevented. It is desirable that the electric conductivity is 10E-8 (1 / Ωcm) or more and 10E-1 (1 / Ωcm) or less. Further, it is preferable that the surface has irregularities as in the case of the metal layer. As a material to be used, for example, In2O3, SnO2, In2O3-SnO2 (IT
O), ZnO, TiO2, Cd2SnO4, crystalline semiconductor layers doped with high concentration impurities, and the like. As a forming method, resistance heating evaporation, sputtering, spraying, CVD,
There is an impurity diffusion method and the like.

A grid-like current collecting electrode 205 (grid) may be provided on the transparent conductive layer in order to efficiently collect current. As a specific material of the current collecting electrode 205, for example, Ti, Cr, Mo, W, Al, Ag, Ni, C
u, Sn, or a conductive paste such as a silver paste. As a method for forming the current collecting electrode 205, sputtering using a mask pattern, resistance heating, a CVD method, a method in which an unnecessary portion is removed by etching after depositing a metal film on the entire surface and patterning is performed,
There are a method of directly forming a grid electrode pattern by photo CVD, a method of forming a mask of a negative pattern of the grid electrode pattern and then plating, a method of printing a conductive paste, and a method of fixing a metal wire with the conductive paste. As the conductive paste, one obtained by dispersing silver, gold, copper, nickel, carbon, or the like in fine powder form in a binder polymer is usually used. As the binder polymer, for example, polyester, epoxy, acrylic, alkyd,
Resins such as polyvinyl acetate, rubber, urethane, and phenol are included.

Finally, to extract the electromotive force, the plus side output terminal 206a and the minus side output terminal 206b are attached to the conductive substrate and the collecting electrode. A method of joining a metal body such as a copper tab to the conductive substrate by spot welding or soldering is adopted,
A method of electrically connecting a metal body to the collecting electrode by a conductive paste 207 or solder is used. Current collecting electrode 205
It is desirable to provide an insulator 208 in order to prevent the output terminal from coming into contact with the conductive metal substrate or the semiconductor layer to cause a short circuit when the device is mounted on the substrate.

The results of an experiment using a photovoltaic element using a pin junction type amorphous silicon semiconductor photoactive layer will be described below.

First, a strain gauge was attached to the non-light-receiving side of the substrate of the photovoltaic element. Thereafter, the initial characteristics were measured. This sample is subjected to stress (strain) in the direction in which the photovoltaic element is pulled (extended) in the horizontal direction of the substrate by a tensile tester. In this case, the peak strain was measured at each strain until the substrate reached 12000 με (1.2% elongation). In this way, the characteristics of the sample with the changed strain amount are measured again, and finally, the SEM (scanning electron microscope)
The observation of the surface of the photovoltaic element was carried out.

The amount of strain is classified into two types, a peak strain amount generated in the tension stage and a residual strain amount remaining when the tension is stopped (FIG. 9). When defects such as cracks occur in a-Si: H at the peak strain point in the tensile stage, even if the subsequent residual strain is completely eliminated,
The defect is not restored. Therefore, peak distortion is important when describing the relationship between the deformable region of the photovoltaic element and the distortion.

FIG. 10 shows the results of the above experiment.

First, the definition of the FF lowering critical value will be described with reference to FIG.

The relationship between the amount of distortion of the photovoltaic element and the rate of change of FF is plotted on a graph. In that case, as shown in FIG. 10, the FF decreases from a point of a certain distortion amount. Since this decrease in FF is a gentle curve, a tangent is drawn as shown in the figure, and the intersection of the two tangents is defined as the FF decrease critical value. In the case of FIG. 10 using a-Si: H, the intersection of the two tangents is 7000 με (0.
7% distortion). That is, when the peak strain exceeds 7000 με, the FF decreases. Therefore, in order to process the photovoltaic element and ensure its reliability, the peak distortion amount for the photovoltaic element during processing must be less than the FF lowering critical value (0.7% for a-Si: H). Is desirable. Under these conditions, in order to deform the photovoltaic element, by using a material having a plastic deformation region below the FF lowering critical value (a-Si: 0.7% in the case of H) as a flexible substrate, FF
Deformation of the substrate below the lowering critical value (0.7% for a-Si: H) deforms the photovoltaic element, and at the same time, does not cause performance degradation in the semiconductor photoactive layer on the substrate. It can be an electromotive element.

Here, FF will be described.

FF = maximum power (Pm) / (short circuit current (Isc)
× open circuit voltage (Voc)). That is, as a physical meaning, the power Pm that can be actually extracted is compared with the product of Voc, which is the value when only the voltage is extracted to the maximum, and Isc, the value when the current is extracted to the maximum. Value. Since the actual value of FF is determined by the forward characteristics of the pn junction, if a leakage current flows through a defect included in the semiconductor substrate to be used or a defect generated at the time of manufacturing the pn junction or a subsequent manufacturing process, FF And the output that should be able to be output is reduced. In this sense, the fact that the FF decreases after the tensile test indicates that the semiconductor layer has a defect due to the tensile test.

As can be seen from the above, a-Si: H
If the peak distortion is 0.7% or more, that is, F.
When a strain equal to or more than the F lowering critical value is given to the photovoltaic element,
It is considered that the photovoltaic element has a defect.

Actually, SE from the light receiving surface side of the photovoltaic element
As a result of observation with M, a large number of cracks in the vertical direction of the flexible substrate were observed in the portion where the strain equal to or more than the critical value for lowering the FF was generated. Also, due to the deterioration of the solar cell characteristics at this time, the substrate /
It is considered that interface peeling of the metal layer / transparent electrode layer / semiconductor active layer / transparent electrode film or interface peeling in the semiconductor active layer has also occurred.

Based on these facts, a method for producing an actual solar cell module will be described below. FIG. 1 shows a plan view and a cross-sectional view of an example of a solar cell module satisfying the conditions of the present invention. In FIG. 1, 101 is a photovoltaic element, 102 is a fibrous inorganic compound, 103 is a transparent organic polymer compound, 104 is a transparent resin film located on the outermost surface, 105 is a back filler, 106 is a back insulating film,
107 is a reinforcing material, and light from the outside is the film 1 on the outermost surface.
03, the light reaches the photovoltaic element 101, and the generated electromotive force is taken out from an output terminal (not shown).
As the photovoltaic element 101, the photovoltaic element as described above is used.

Next, the processing used in the present invention will be described in detail. First, after a flat-plate solar cell module to which a reinforcing material is attached is formed, bending processing as shown in FIG. 1 is performed. In FIG. 1, the bending is performed stepwise in the middle of the photovoltaic element. The places where distortion occurs in this processing are step-like peaks and valleys. However, the largest distortion occurs in the step-shaped peaks. Distortion also occurs in the valley, but is very slight.

FIG. 1 shows an example of processing in a continuous step shape, but the present invention is not limited to this. In the case of processing in which the amount of distortion of the flexible substrate is plastically deformed below the FF lowering critical value, only a part is provided with a bent portion, or a substrate having a large number of uneven portions or a flat solar cell module is pulled as it is. Processing that gives stress may be performed. Since a solar cell module can be processed with or without a photovoltaic element, a large-sized solar cell module works as shown in FIG. It is excellent, and since it is not necessary to provide a joint for each sheet, a roof with few joints and excellent workability is obtained. Further, it is not necessary to change the arrangement of the photovoltaic elements depending on the form of the solar cell module, and the same flat solar cell module can be processed into various shapes, so that the workability and productivity are excellent. Specifically, when considering processing of a solar cell module provided with a reinforcing material, a material having higher rigidity than the substrate is often used as the reinforcing material. It is difficult to maintain the processed shape. In that case, as an example for processing the shape of the solar cell module, a method of plastically deforming only a portion without a photovoltaic element on the reinforcing material, thereby performing a processing such that the entire reinforcing material can maintain the shape. There is. According to this method, even in a solar cell module provided with a reinforcing material, the amount of distortion of the flexible substrate can be reduced to a value less than the critical value for lowering the FF and processed as a solar cell module, and the shape can be maintained. A solar cell module excellent in both properties can be obtained.

Next, the coating material used in the present invention will be described in detail.

(Fibrous Inorganic Compound) Next, the fibrous inorganic compound 102 impregnated in the surface filler will be described below. First, the surface of a solar cell using amorphous silicon is covered with a polymer resin film in order to make full use of its flexibility. However, in this case, the outermost surface is much more vulnerable to external flaws than when the outermost surface is covered with glass.

Also, solar cell modules, particularly modules installed on roofs and walls of houses, are required to have flame retardancy. However, when the amount of the transparent organic polymer resin is large, the surface coating material becomes very flammable, and when the amount is small, the internal photovoltaic element cannot be protected from external impact. Therefore, in order to sufficiently protect the photovoltaic element from the external environment with a small amount of resin, a transparent polymer resin impregnated with a fibrous inorganic compound is used as a surface coating material.

Specific examples of the fibrous inorganic compound include glass fiber nonwoven fabric, glass fiber woven fabric, glass filler and the like. In particular, it is preferable to use a glass fiber nonwoven fabric. Glass fiber woven fabrics are expensive and are not easily impregnated. Since the use of a glass filler does not significantly improve the scratch resistance, it is difficult to cover the photovoltaic element with a smaller amount of the transparent organic polymer resin. In addition, for long-term use, it is possible to treat the fibrous inorganic compound with a silane coupling agent or an organic titanate compound in the same manner as that used for the transparent organic polymer resin to ensure sufficient adhesion. desirable.

(Filler) The transparent organic polymer resin used as the surface filler 103 covers the unevenness of the photovoltaic element with the resin, and the element is exposed to a severe external environment such as temperature change, humidity and impact. It is necessary to protect and secure the adhesion between the surface film and the element. Therefore, weather resistance, adhesion, filling properties, heat resistance, cold resistance, and impact resistance are required.
Resins satisfying these requirements include polyolefin resins such as ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), and butyral resin. , Urethane resin, silicone resin and the like. Among them, EVA has well-balanced physical properties for use in solar cells, and is preferably used.

Further, since EVA has a low heat deformation temperature as it is and easily exhibits deformation and creep under high-temperature use, it is desirable to crosslink to increase heat resistance. E
In the case of VA, crosslinking is generally performed with an organic peroxide. Crosslinking with an organic peroxide is performed by free radicals generated from the organic peroxide extracting hydrogen and halogen atoms in the resin to form a CC bond. Thermal decomposition, redox decomposition and ionic decomposition are known as methods for activating organic peroxides. Generally, the thermal decomposition method is preferred. Specific examples of the chemical structure of the organic peroxide are roughly classified into hydroperoxide, dialkyl (allyl) peroxide, diacyl peroxide, peroxyketal, peroxyester, peroxycarbonate, and ketone peroxide.

The amount of the organic peroxide to be added depends on the filler resin
0.5 to 5 parts by weight per 100 parts by weight.

It is possible to carry out crosslinking and thermocompression while heating under pressure while using the above organic peroxide as a filler. The heating temperature and time can be determined by the thermal decomposition temperature characteristics of each organic peroxide. In general, the heating and pressurizing is completed when the temperature and the time at which the thermal decomposition proceeds are more than 90%, preferably 95% or more. The gel fraction of the filler is preferably 80% or more. Here, the gel fraction is determined by the following equation.

Gel fraction = (weight of undissolved portion / original weight of sample) × 100 (%) That is, when the transparent organic polymer resin is extracted with a solvent such as xylene, the crosslinked and gelled portion is Only the uncrosslinked sol is eluted without elution.
A gel fraction of 100% indicates that the crosslinking was completely completed. By evaporating the xylene from which the sample remaining after the extraction has been taken out, only the undissolved gel component can be obtained.

If the gel fraction is less than 80%, heat resistance and creep resistance are inferior, so that a problem arises when used at high temperatures such as summer.

In order to carry out the above crosslinking reaction efficiently, it is desirable to use triallyl isocyanurate (TAIC), which is called a crosslinking assistant. Generally, the amount is 1 to 5 parts by weight based on 100 parts by weight of the filler resin.

Although the filler material used in the present invention is excellent in weather resistance, an ultraviolet absorber can be used in combination for further improving weather resistance or protecting the lower layer of the filler. . Known compounds are used as the ultraviolet absorber, but it is preferable to use a low-volatile ultraviolet absorber in consideration of the usage environment of the solar cell module. If a light stabilizer is added in addition to the ultraviolet absorber, the filler becomes more stable to light. Specific chemical structures are roughly classified into salicylic acid, benzophenone, benzotriazole, and cyanoacrylate.
It is preferable to add at least one of these ultraviolet absorbers.

It is known that a hindered amine-based light stabilizer can be used as a method for imparting weather resistance other than the above-mentioned ultraviolet absorber. A hindered amine-based light stabilizer does not absorb ultraviolet rays unlike an ultraviolet absorber, but exhibits a remarkable synergistic effect when used in combination with an ultraviolet absorber. The addition amount is 0.1 to 0.3 with respect to 100 parts by weight of the resin.
It is generally about parts by weight. Of course, some other than hindered amines function as light stabilizers, but are often colored, which is not desirable for the filler of the present invention.

Further, an antioxidant can be added for improving heat resistance and heat workability. Addition amount is resin 1
0.1 to 1 part by weight is appropriate for 00 parts by weight. The chemical structure of antioxidants is broadly classified into monophenol-based, bisphenol-based, polymer-type phenol-based, sulfur-based, and phosphoric-acid-based.

Further, when it is assumed that the solar cell module is used in a more severe environment, it is preferable to improve the adhesion between the filler and the photovoltaic element or surface film. The adhesion can be improved by adding a silane coupling agent or an organic titanate compound to the filler. The addition amount is based on 100 parts by weight of the filler resin.
0.1 to 3 parts by weight is preferable, and 0.25 to 1 part by weight is more preferable. Further, it is effective to add a silane coupling agent or an organic titanate compound to the transparent organic polymer in order to improve the adhesion between the impregnated fibrous inorganic compound and the transparent organic polymer compound.

On the other hand, in order to minimize the decrease in the amount of light reaching the photovoltaic element, the surface filler must be transparent, and specifically, the light transmittance must be 400 nm or more and 800 n.
It is preferably at least 80%, more preferably at least 90%, in the visible light wavelength region of m or less. In addition, in order to facilitate the incidence of light from the atmosphere,
Preferably, the refractive index in degrees is from 1.1 to 2.0, more preferably from 1.1 to 1.6.

(Surface Resin Film) Since the surface resin film 104 used in the present invention is located on the outermost layer of the solar cell module, it has long-term reliability in outdoor exposure of the solar cell module including weather resistance, stain resistance and mechanical strength. Performance to ensure performance is required. Examples of the resin film used in the present invention include a fluorine resin and an acrylic resin. Among them, fluororesins are preferably used because of their excellent weather resistance and stain resistance. Specific examples include a polyvinylidene fluoride resin, a polyvinyl fluoride resin, and an ethylene-tetrafluoroethylene-ethylene copolymer. Polyvinylidene fluoride resin is excellent in terms of weather resistance, but ethylene tetrafluoride-ethylene copolymer is excellent in terms of compatibility between weather resistance and mechanical strength and transparency.

In order to improve the adhesiveness with the filler, it is desirable that the surface film is subjected to a surface treatment such as a corona treatment, a plasma treatment, an ozone treatment, a UV irradiation, an electron beam irradiation, and a flame treatment. Specifically, it is preferable that the wetting index on the photovoltaic element side is 34 dyne to 45 dyne. If the wetting index is 34 dyne or less, the adhesive strength between the resin film and the filler is not sufficient, so that the filler and the resin film peel off. When using a resin film of ethylene tetrafluoride-ethylene copolymer resin,
It is difficult to make the wetting index more than 45dyne.

Further, the resin film which has been subjected to the stretching treatment has cracks. That is, when the end portion of the solar cell module is bent as in the present invention, the film is cut at the bent portion, so that peeling of the coating material and intrusion of moisture at the bent portion are promoted, and reliability is reduced. For this reason, a film that has not been stretched is more desirable. Specifically, in the ASTM D-882 test method, the tensile elongation at break was 200%
It is preferably from about to 800%.

(Insulating Film) The insulating film 106
It is necessary to maintain electrical insulation between the conductive metal substrate of the photovoltaic element 101 and the outside. As the material, a material that can secure sufficient electrical insulation with the conductive metal substrate, has excellent long-term durability, can withstand thermal expansion and thermal contraction, and has flexibility is preferable. Suitable films include nylon, polyethylene terephthalate, and polycarbonate.

(Back Filler) The back filler 105 is for bonding the photovoltaic element 101 and the insulating film 106 on the back. As the material, a material that can secure sufficient adhesion to the conductive substrate, has excellent long-term durability, can withstand thermal expansion and thermal contraction, and has flexibility is preferable. Materials that are preferably used include EVA, ethylene-methyl acrylate copolymer (EMA), and ethylene-methyl acrylate.
Ethyl acrylate copolymer (EEA), polyethylene,
Examples include a hot melt material such as polyvinyl butyral, a double-sided tape, and a flexible epoxy adhesive. In addition, a tackifying resin may be applied to the surface of these adhesives in order to improve the adhesive strength with the reinforcing plate and the insulating film. These fillers are often the same material as the transparent polymer resin used as the filler 103 on the surface.
Furthermore, to simplify the process, on both sides of the insulating film,
A material in which the above-mentioned adhesive layer is integrally laminated in advance may be used.

(Reinforcing plate) Outside the covering film on the back surface, in order to increase the mechanical strength of the solar cell module, to prevent distortion and warping due to temperature change, and to provide a roof material integrated solar cell. A reinforcing plate 107 is attached to make a module. For example, a coated zinc steel plate, a plastic plate, an FRP (glass fiber reinforced plastic) plate or the like coated with an organic polymer resin having excellent weather resistance and rust resistance are preferable.

Using the above-described photovoltaic element, filler, surface resin film, backside covering material, and reinforcing plate, a roof with a flat solar cell is formed, and the end is bent and the portion including the photovoltaic element is bent. The processing method will be described below.

In order to cover the light receiving surface of the photovoltaic element, it is general to prepare a sheet-shaped transparent polymer resin 303 and heat-press it on the front and back of the element. The stacked configuration at the time of producing the solar cell module is a configuration as shown in FIG. That is, the photovoltaic element 301, the fibrous inorganic compound 302, the transparent organic polymer resin 303, the front resin film 304, the back filler 305, the insulating film 3
06 and the reinforcing plate 307 are laminated in the order shown in the drawing or in the reverse order, and then heat-pressed to obtain the solar cell module 308.

The heating temperature and the heating time at the time of pressing are determined by the temperature and time at which the crosslinking reaction sufficiently proceeds.

The thus-formed solar cell module 308 is processed into a plastic deformation region by a press molding machine, a roller former molding machine, and a bender bending molding machine to obtain a solar cell module.

[0083]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.

Example 1 Photovoltaic Element First, amorphous silicon (a-S
i) Produce a solar cell (photovoltaic element). The manufacturing procedure will be described with reference to FIG.

On a cleaned stainless steel substrate 201, an Al layer (film thickness: 5000) was formed as a back reflection layer 202 by sputtering.
Å) and a ZnO layer (thickness 5000 Å) are sequentially formed. Then, SiH4, PH3, and H2 were formed by plasma CVD.
To form an n-type a-Si layer from a mixed gas of (i), an i-type a-Si layer from a mixed gas of SiH4 and H2, and a p-type microcrystalline μc-Si layer from a mixed gas of SiH4, BF3 and H2. 150Å / i-layer thickness 4000Å / p-layer thickness 100Å / n
Layer thickness 100 ° / i-layer thickness 800 ° / p-layer thickness 100 °
Tandem a-Si photoelectric conversion semiconductor layer 203 having a layer structure of
Was formed. Next, as the transparent conductive layer 204, In2O3
A thin film (thickness: 700 °) was formed by depositing In by a resistance heating method in an O2 atmosphere. Furthermore, a grid electrode 205 for current collection is formed by screen printing of silver paste, and finally a copper tab is attached to the stainless steel substrate as a negative output terminal 206a using a solder 207,
As the positive output terminal 206b, a tin foil tape was attached to the current collecting electrode 205 with solder 207 to serve as an output terminal, and a photovoltaic element was obtained.

[Cell Block] A method of fabricating a solar cell block by connecting the above elements in five series will be described with reference to FIG.

After arranging the five elements in a horizontal row, the plus terminal 503a of one of the adjacent elements and the minus terminal 503b of the other element are connected to each other with a copper tab 504 using solder 505. Further, the five elements were serialized by this, and a serialized cell block was created. The copper tab connected to the output terminal of the element at the end was turned to the back side, and a back side current collecting electrode was created so that output could be taken out from the hole of the back side covering layer described later.
(Not shown).

Thus, a solar cell block was completed.

[Modularization] A method for producing a solar cell module by covering the above-described elements will be described with reference to FIG. Cell block 601, fibrous inorganic compound (40 g / m2) 6
02, transparent organic polymer resin 603 on the light receiving surface side, front surface resin film 604, back side integrated laminated film 606, reinforcing plate 6
07 were prepared, and these were laminated by the order of FIG.

The positive output terminal 60 of the cell block
On top of 9, a decorative tape 608 was laminated.

<Fibrous Inorganic Compound> Fibrous inorganic compound (40 g / m 2) A nonwoven glass fabric having a basis weight of 40 g / m 2, a thickness of 200 μm, a binder containing acrylic resin of 4.0%, a wire diameter of 10 μm and a fiber length of 13 mm was prepared. Got ready.

<Transparent Organic Polymer Resin on the Light-Receiving Side> A mixture of an ethylene-vinyl acetate copolymer (25% by weight of vinyl acetate) as a filler, a crosslinking agent, an ultraviolet absorber, an antioxidant, and a light stabilizer. A preformed 460 μm EVA sheet was prepared.

<Surface Resin Film> An unstretched ethylene-tetrafluoroethylene film (ETFE) 50 μm was prepared as a surface resin film. Note that a surface in contact with the filler was subjected to plasma treatment in advance.

<Integral backside laminated film> As an integral laminated film, as an adhesive layer, a formulated ethylene-vinyl acetate copolymer (25% by weight of vinyl acetate, thickness of 225 μm) used as an organic polymer resin on the light-receiving side. A biaxially stretched polyethylene terephthalate film (PET) (thickness: 100 μm) was used as an insulating film in an EVA / PET /
An integrated laminated film having a total thickness of 550 μm, which was integrally laminated in the order of EVA, was prepared.

<Reinforcing Plate> As a reinforcing plate, a galvalume steel plate (aluminum 55%, zinc 43.4%, silicon 1.6
A steel sheet coated with a polyester-based paint on one side and a polyester-based paint with glass fiber added on the other side was prepared. The steel plate was 400 μm thick.

<Cosmetic Tape> As a decorative tape, a polyethylene terephthalate (PET) film (thickness: 50)
μm, color black) tape was prepared.

<Flat-plate Solar Cell Module> This laminate was vacuum-heated using a single vacuum laminating apparatus to produce a flat-plate solar cell module. The vacuum conditions at that time were as follows: evacuation speed: 76 Torr / sec., Degree of vacuum: 5 Torr, evacuation for 30 minutes. Thereafter, the laminating apparatus was put into a hot air oven at 160 ° C. and heated for 50 minutes. EVA at this time is
It is in an environment of 140 degrees or more and 15 minutes or more. Thereby, EVA was melted and crosslinked.

[Roller former processing] Next, FIG.
As described above, the end portion of the solar cell module not including the photovoltaic element was bent using a roller former molding machine. At this time, the photovoltaic element is formed so that the roller does not hit the part.

[Press Processing] Next, as shown in FIG. 4-2, the reinforcing plate was bent by a press molding machine regardless of the presence or absence of the photovoltaic element. Pressing was performed by sandwiching the solar cell module between a lower mold having a convex portion and an upper mold having a concave portion. At this time, the pressing conditions were adjusted so that the peak strain of the flexible substrate of the photovoltaic element was 0.6% (residual strain 0.4%).

Finally, an electric wire for extracting power is attached from the back of the solar cell module. A hole is preliminarily formed in the reinforcing material corresponding to the terminal extracting portion of the photovoltaic element group, and the positive and negative output terminals are extracted therefrom. In addition, a terminal box made of polycarbonate is provided at the take-out part for insulation protection and waterproofing. A cable having a connector at the end is used as the cable.

Example 2 In Example 1, the pressing conditions were such that the peak distortion of the flexible substrate of the photovoltaic element was 0.3.
% (Residual strain amount: 0.1%). A solar cell module was prepared in the same manner as in Example 1 except for the pressing conditions.

(Example 3) A solar cell module was prepared in the same manner as in Example 1, except that a polyimide film was used as a substrate of the photovoltaic element.

Example 4 FIG. 7 shows a solar cell module of Example 4.

A photovoltaic element was prepared in the same manner as in Example 1, and the other steps were described below.

[Cell Block] A solar cell block was prepared by connecting the above elements in series of five. The creation method is the same as in the first embodiment.

[Flat Plate Solar Cell Module] A flat plate solar cell module was prepared in the same manner as in Example 1 using the above-mentioned five series solar cell blocks.

[End Bending] Four corners of the flat panel solar cell module were cut with a corner shear. afterwards,
The short side end was turned 180 °, and the long side was bent 90 ° to the light receiving surface side by bender processing. The rising height of the bent portion on the long side was 25 mm.

[Press Processing] A curvature portion was provided by press processing. The solar cell module was sandwiched between a lower mold having a convex portion and an upper mold having a concave portion. Press processing was performed so that the peak strain amount of the substrate of the photovoltaic element was 0.6% (residual strain amount 0.4%).

Example 5 A solar cell module was prepared in the same manner as in Example 4, except that a polyimide film was used as the substrate of the photovoltaic element.

(Comparative Example 1) In Example 1, the peak distortion of the substrate of the photovoltaic element was set to 0.9% (residual distortion 0.7%).
A solar cell module was prepared in the same manner except that pressing was performed so that

Comparative Example 2 In Example 1, the peak distortion of the substrate of the photovoltaic element was reduced to 1.4% (residual distortion 1.2%).
A solar cell module was prepared in the same manner except that pressing was performed so that

Comparative Example 3 In Example 1, the peak distortion of the substrate of the photovoltaic element was 4.8% (the residual distortion was 4.4%).
A solar cell module was prepared in the same manner except that pressing was performed so that

(Comparative Example 4) In Example 3, the peak distortion of the substrate of the photovoltaic element was reduced to 1.4% (residual distortion 1.2%).
A solar cell module was prepared in the same manner except that pressing was performed so that

(Comparative Example 5) In Example 4, the peak distortion of the substrate of the photovoltaic element was reduced to 1.4% (residual distortion 1.2%).
A solar cell module was prepared in the same manner except that pressing was performed so that

The following items were evaluated. Table 1 shows the results.

[0116]

[Table 1]

● Initial Appearance The initial appearance of the solar cell module (final form), such as insufficient filling and damage to the solar cell surface, was evaluated. At the same time,
Evaluation was also made on the aesthetics of the processed solar cell module as a building material and a roofing material. The evaluation results are shown in Table 1 based on the following evaluation criteria. ◎: Defects in appearance are completely excellent and aesthetics as a building material and a roofing material are good. ○: Defects in appearance are a little but cannot be practically used. ×: Poor filling, scratches on surface. When the appearance defect is extremely large or the appearance of building materials and roofing materials is significantly impaired.

● High-Temperature and High-Humidity Test After the solar cell module was put in an environment of 85 degrees / 85% (relative humidity) for 3000 hours, the solar cell module was taken out, and changes in appearance were visually observed. Also, A
The conversion efficiency under light irradiation of M1.5 and 100 mW / cm2 was measured, and the rate of change from the initial value before introduction was determined. The evaluation results are shown in Table 1 based on the following evaluation criteria. Appearance) ◎: No appearance defect at all, ○: Some appearance defect but not practically impracticable, ×: Remarkable peeling, etc., and very large appearance defect Conversion efficiency) ◎: Conversion When the change in efficiency is less than 1.0%, ○: when the change in conversion efficiency is 1.0% or more and less than 3.0%, Δ: when the change in conversion efficiency is 3.0% to 5.0%,
×: when the change in conversion efficiency is 5.0% or more.

● Temperature / humidity cycle test The solar cell module was subjected to a temperature / humidity cycle test of -40 degrees / 0.5 hours: 85 degrees / 85% (relative humidity) / 20 hours 100 times, and then the solar cell module was taken out. The change in appearance was visually observed. The conversion efficiency was measured under irradiation with light of AM 1.5 and 100 mW / cm 2, and the rate of change from the initial value before injection was determined. Table 1 shows the evaluation results based on the following evaluation criteria.
Shown in Appearance) ◎: No appearance defect at all, ○: Some appearance defect but not practically impracticable, ×: Remarkable peeling, etc., and very large appearance defect Conversion efficiency) ◎: Conversion When the change in efficiency is less than 1.0%, ○: when the change in conversion efficiency is 1.0% or more and less than 3.0%, Δ: when the change in conversion efficiency is 3.0% to 5.0%,
×: when the change in conversion efficiency is 5.0% or more.

● Forward bias high-temperature high-humidity storage (HHFB test) The solar cell module is put in an environment of 85 degrees / 85% (relative humidity). In this case, light is prevented from being incident on the test object by either setting the inside of the test apparatus to a light-shielding environment or shielding the light receiving surface side of the test object from light. Under this environment, wiring was performed so that the optimum operating voltage (Vmp) could be applied in the forward direction of the internal PV circuit (diode component) of the solar cell, and after applying for 2000 hours, the solar cell module was taken out and the photovoltaic element 1 was removed. Low light Voc per cell
(Open-circuit voltage (Voc) under an illuminance of 200 Lx) was measured, and a rate of change from an initial value before the injection was obtained. A decrease in the low illuminance Voc indicates a decrease in the shunt resistance due to a junction defect inside the photovoltaic element. That is, it indicates an increase in internal defects. The evaluation results are shown in Table 1 based on the following evaluation criteria. ◎: When the change in low illuminance Voc is less than 1.0%, ：:
When the change in low illuminance Voc is 1.0% or more and less than 3.0%, Δ: when the change in low illuminance Voc is 3.0% or more and less than 5.0%, x: change in low illuminance Voc Is 5.0% or more.

● Reverse bias high-temperature high-humidity storage (HHRB test) The solar cell module is put in an environment of 85 degrees / 85% (relative humidity). In this case, light is prevented from being incident on the test object by either setting the inside of the test apparatus to a light-shielding environment or shielding the light receiving surface side of the test object from light. Under this environment, wiring was performed so that the operation voltage (Vf) of the bypass diode could be applied in the reverse direction of the internal PV circuit (diode component) of the solar cell, and after applying for 2,000 hours,
The solar cell module is taken out, and the low illuminance Voc (open circuit voltage (illuminance under 200 Lx illuminance)
oc)) was measured and the rate of change from the initial value before introduction was determined.
A decrease in the low illuminance Voc indicates a decrease in the shunt resistance due to a junction defect inside the photovoltaic element. That is, it indicates an increase in internal defects. The evaluation results are shown in Table 1 based on the following evaluation criteria. ◎: When the change in low illuminance Voc is less than 1.0%, ：:
When the change in low illuminance Voc is 1.0% or more and less than 3.0%, Δ: when the change in low illuminance Voc is 3.0% or more and less than 5.0%, x: change in low illuminance Voc Is 5.0% or more.

● Outdoor exposure The solar cell module was installed outdoors (4-1-1, Kizugawadai, Kizu-cho, Kizu-cho, Soraku-gun, Kyoto Prefecture). Three months, six months, and 12 months after the exposure was performed. Was evaluated. Low illumination Voc per cell of photovoltaic element
(Open-circuit voltage (Voc) under an illuminance of 200 Lx) was measured, and a rate of change from an initial value before the injection was obtained. The evaluation was performed according to the following criteria. ◎: When the change in low illuminance Voc is less than 1.0%, ：:
When the change in the low illuminance Voc is 1.0% or more and less than 3.0%, Δ: When the change in the low illuminance Voc is 3.0% or more and less than 5.0%, x: The change in the low illuminance Voc Is 5.0% or more.

● SEM Observation A place which seems to have the largest amount of distortion in the solar cell module was cut out and observed with a scanning electron microscope (SEM). The evaluation was performed according to the following criteria. ：: No crack was found on the surface of the photovoltaic element, ×: Crack was found on the surface of the photovoltaic element.

As is clear from Table 1, the solar cell modules of the examples also have good initial appearance and appearance after the high-temperature / high-humidity test and the temperature-humidity cycle test. In Example 2, the residual distortion was set to a small distortion amount of 0.1% in the solar cell module, so that the impression that the processing was slightly weak was given, but this was not a problematic level. Further, from the viewpoint of electrical characteristics, the low illuminance Voc does not decrease even in the forward and reverse bias high temperature and high humidity tests (HHFB and HHRB). After 12 months of outdoor exposure, no performance degradation or defect was observed. The surface of the photovoltaic element of the solar cell module according to the embodiment was SEM
As a result, no crack was observed, and there was no inconsistency with the above test result, and a highly reliable solar cell module could be produced.

On the other hand, in the solar cell module of Comparative Example 1 in which the peak strain amount during processing was 0.9% and the residual strain amount was 0.7%, cracks were observed by SEM.
This is because the photovoltaic element once received a strain of 0.9% during processing, and it is considered that cracks occurred on the element surface at this time. When this sample was subjected to the forward and reverse bias tests, the low illuminance Voc decreased around 1500 hours. Even in outdoor exposure, the low-light Voc gradually decreased from about 6 months after exposure.

In the solar cell modules of Comparative Examples 2, 4, and 5 in which the peak strain during processing was 1.4% and the residual strain was 1.2%, many cracks were observed by SEM observation. In the HHFB and HHRB tests, the low illuminance Voc was reduced around 1200 hours. In the outdoor exposure test, the low-light Voc was reduced at the third month of exposure. In addition, the appearance after the high-temperature / high-humidity test and the temperature-humidity cycle test is not a problematic level, but some whitening of the coating material occurs. 4.8% peak strain during processing, 4% residual strain.
In the solar cell module of Comparative Example 3 with 4%, it can be seen that even on the initial appearance after processing, a dent is formed on the photovoltaic element (color has changed). Obviously, a large number of cracks have been confirmed by SEM observation. Low illumination in less than 1000 hours in HHFB and HHRB tests
Voc has been reduced, and is consistent with the observation of cracks. Furthermore, in the appearance of the coating material, whitening was confirmed in the processed part from the beginning, and this became even more noticeable after the high-temperature high-humidity test and the temperature-humidity cycle test.
There is also a problem with the aesthetics of the roofing material.

[0127]

According to the present invention, since the deformable region of the photovoltaic element is clarified, the speed of developing various types of solar cell modules is greatly improved. Further, since the photovoltaic element can be freely processed without deteriorating the characteristics of the solar cell, a solar cell module having excellent aesthetics and design can be obtained. The solar cell module molded in this way becomes a solar cell module that has ensured high reliability for a long time.

[Brief description of the drawings]

FIG. 1 is a plan view and a sectional view of a solar cell module according to the present invention.

FIG. 2 is a diagram showing an example of a photovoltaic element that can be used in the solar cell module of the present invention.

FIG. 3 is a stacking diagram when the solar cell module of the present invention is produced.

FIG. 4A is a diagram illustrating a solar cell module after end bending processing, and FIG. 4B is a diagram illustrating a solar cell module after final bending processing.

FIG. 5 is a plan view and a sectional view of a cell block.

FIG. 6 is a diagram showing a solar cell module of Example 1.

FIG. 7 shows a solar cell module of Example 4.

FIG. 8 is a schematic sectional view showing an example of a conventional solar cell module.

FIG. 9 is a graph showing an example of a distortion amount during processing of a photovoltaic element.

FIG. 10 is a diagram showing the relationship between the peak strain amount of a-Si: H and FF.

[Explanation of symbols]

101,301,401,501,601,701,8
01 Photovoltaic element 102, 302, 602 Fibrous inorganic compound 103, 303, 603, 802 Transparent organic polymer resin 104, 304, 604, 803 Surface resin film 105, 305, 605 Backside filler 106, 306, 606 804 Backside insulating film 107, 307, 607, 803 Reinforcement plate 201 Conductive substrate 202 Backside reflective layer 203 Semiconductor photoactive layer 206b, 503b Negative side output terminal 207 Conductive paste 208, 502 Insulating film 308 Solar cell module 504 Series member 505 Solder 601 Cell block 608 Backside integrated film 702 Short side 180 ° bent part 703 Long side 90 ° bent part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Meiji Takabayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Kimitoshi Fukae 3- 30-2 Shimomaruko, Ota-ku, Tokyo Inside the corporation

Claims (32)

[Claims] 1. A solar cell module having a photovoltaic element having at least one semiconductor photoactive layer on a flexible substrate, wherein at least a part of the flexible substrate is reduced in FF in a horizontal direction of the substrate material. A solar cell module, wherein a photovoltaic element is deformed by tensile deformation with a strain amount less than a critical value. 2. The tensile deformation is within a plastic deformation region of a reinforcing member provided on the non-light-receiving surface side of the flexible substrate or the photovoltaic element, and is less than a critical value of FF lowering of the photovoltaic element. The solar cell module according to claim 1, wherein the solar cell module has a distortion amount of: 3. The solar cell module according to claim 1, wherein at least a light receiving surface side of the photovoltaic element is coated with an organic polymer resin. 4. The solar cell module according to claim 1, wherein a reinforcing material is provided on a non-light receiving surface side of the photovoltaic element. 5. The solar cell module according to claim 1, wherein a transparent resin film layer is provided on the outermost surface on the light receiving surface side of the solar cell module. 6. The solar cell module according to claim 1, wherein the reinforcing member has a strain in a plastic deformation region. 7. The solar cell module according to claim 1, wherein the plastic deformation region of the reinforcing member is only a portion not including a photovoltaic element on a light receiving surface side. 8. The solar cell module according to claim 1, wherein the optical semiconductor active layer is made of amorphous silicon. 9. The strain amount of the FF lowering critical value is 0.7%.
The solar cell module according to claim 8, wherein 10. The solar cell module according to claim 1, wherein the flexible substrate is a conductive substrate. 11. The solar cell module according to claim 1, wherein the plastic deformation region is 0.2% or more. 12. The solar cell module according to claim 1, wherein the conductive substrate is made of stainless steel. 13. The solar cell module according to claim 1, wherein the flexible substrate is a resin film. 14. The solar cell module according to claim 1, wherein the reinforcing member is a metal. 15. The solar cell module according to claim 1, wherein the solar cell module is a building material-integrated solar cell module.
15. The solar cell module according to any one of items 14 to 14. 16. A solar cell module having a photovoltaic element having at least one semiconductor photoactive layer on a flexible substrate, wherein at least a part of the flexible substrate is reduced in FF in a horizontal direction of the substrate material. A method for manufacturing a solar cell module, wherein a photovoltaic element is deformed by tensile deformation with a strain amount less than a critical value. 17. The method according to claim 16, wherein the tensile deformation is less than the FF lowering critical value of the flexible substrate or the plastic deformation region of the reinforcing member provided on the non-light-receiving surface side of the photovoltaic element. 17. The method for manufacturing a solar cell module according to claim 16, having a distortion amount. 18. The method for manufacturing a solar cell module according to claim 16, wherein said deforming means is formed by press molding. 19. The method for manufacturing a solar cell module according to claim 16, wherein said means for deforming is by pulling in a horizontal direction. 20. The method for manufacturing a solar cell module according to claim 16, wherein at least a light receiving surface side of the photovoltaic element is coated with an organic polymer resin. 21. The method for manufacturing a solar cell module according to claim 16, wherein a reinforcing material is provided on a non-light-receiving surface side of the photovoltaic element. 22. The method for manufacturing a solar cell module according to claim 16, wherein a transparent resin film layer is provided on the outermost surface on the light receiving surface side of the solar cell module. 23. The method for manufacturing a solar cell module according to claim 16, wherein the reinforcing member has a strain in a plastic deformation region. 24. The plastic deformation region of the reinforcing member is only a portion that does not include a photovoltaic element on the light receiving surface side, whereby the solar cell module is processed to maintain the shape. A method for manufacturing the solar cell module according to the above. 25. The method for manufacturing a solar cell module according to claim 16, wherein said optical semiconductor active layer is made of amorphous silicon. 26. The method for manufacturing a solar cell module according to claim 25, wherein a strain amount of the FF lowering critical value is 0.7%. 27. The method according to claim 16, wherein the flexible substrate is a conductive substrate. 28. A plastically deformed area of the conductive substrate is 0.2%
28. The method for manufacturing a solar cell module according to claim 16, wherein: 29. The method according to claim 16, wherein the conductive substrate is made of stainless steel. 30. The method according to claim 16, wherein the flexible substrate is a resin film. 31. The method for manufacturing a solar cell module according to claim 16, wherein the reinforcing material is a metal. 32. The solar cell module is a building material-integrated solar cell module.
32. The method for manufacturing a solar cell module according to any one of the above items.