JP3467424B2 - Solar cell module - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable solar cell module typified by electronic equipment applications in which solar cells are mounted, and more specifically, a solar cell module as a photovoltaic device is integrated. The present invention relates to a solar cell module having a color tone, especially a harmony in design, which does not give a feeling of strangeness when the solar cell is mounted.

[0002]

2. Description of the Related Art Solar cells are used in various electronic devices as a power source to replace dry cells and the like. In particular, low-power electronic devices such as electronic desk calculators, watches, and portable electronic devices (cameras, mobile phones, consumer-use radar detectors), etc. can be sufficiently driven by the electromotive force of the solar cell, and battery replacement is required. Is not needed, it can be operated semi-permanently, and it is environmentally friendly, so it is attracting attention.

By the way, when such a solar cell is mounted in an electronic device, it is necessary to consider the design. In particular, recent electronic devices are difficult to compare in terms of performance, and consumer preferences for products often depend on good or bad design. Due to the structure of the solar cell, the mechanism of the light receiving surface is visually recognized from the outside. For this reason, the difference in lightness or color difference between the photoelectric conversion part having the photoelectric conversion function of the light-receiving surface and the other parts such as electrodes, partition walls, etc., has a great influence on the design. In general, these structures often have an adverse effect on the design when they are recognized from the outside.

Japanese Patent Laid-Open No. 60-148174 discloses light in a wavelength range that selectively reflects visible light having a specific wavelength on the front surface of a solar cell, transmits the remaining light, and contributes to power generation of the solar cell. A selective reflection layer (multilayer film interference filter such as dichroic mirror) that transmits at least a part of
Furthermore, a solar cell having a light diffusion layer on its front surface is described. With such a structure, the solar cell having a dark color is used as the lowermost layer, the "selective reflection layer" is provided on the upper layer on the light-receiving surface side, the color tone is changed to a desired color, and the "diffuse transmission layer" is further provided on the upper layer. The color of reflected light is made brighter.
There is a description that the dark color of the solar cell can be reduced and the color tone can be controlled to some extent, and the degree of freedom in design design including the color tone of the mounted system can be widened to alleviate discomfort in product design due to mounting the solar cell.

The solar cell module which has been put into practical use at present has a photovoltaic cell obtained from a photoelectric conversion film through a transparent electrode or the like, and a comb-shaped collecting electrode such as an Ag conductive film formed on the transparent electrode or an outer periphery thereof. It has conductive films such as Ag, Cu, Ni, Mo and their alloys, carbon black, graphitized carbon black, etc. as partial wiring electrodes. As the transparent conductive film, a SnO ₂ -doped ITO film, a SnO ₂ film (including Sb and F-doped type), a ZnO film (In, Al,
(Including Si-doped type) are known, and among them, ITO
Is common. In addition to this, forming a multi-stage cell structure for obtaining a desired high voltage on one substrate,
Having a printed insulating film for patterning required for series connection, or performing laser scribing patterning created by a dry process, and further printing an insulating resin on it to provide partition walls, Similarly, it has an integrated structure in which a conductive ink is printed and a laser bonding structure is provided (particularly more easily in the case of a film solar cell, where the integrated structure is easily formed). The color tone seen from such a solar cell light-receiving surface is an interference color of the transparent electrode thin film (determines most of the color tone of the solar cell) and a uniform color tone surface shown by overlapping the color tone of the α-Si photoelectric conversion film, Patterns of various line widths having optical characteristics such as high light reflectance, high light absorption rate, high light transmission rate, specific wavelength band absorption rate, etc. due to the above-mentioned integrated structure formation interfering with the harmony of color tone in design. Is the reality.

There is a patterning method in which a transparent electrode by a sputtering method, a photoelectric conversion film by a plasma CVD method, a metal electrode by a sputtering method, and the like are integrated on a substrate by a metal mask without using screen printing or laser scribing. Among them, since the metal electrode applied to the mask shielding portion has a particularly high reflectance, the high contrast with the light conversion film portion of the non-mask shielding portion prevents discomfort even if the diffusion / transmission layer is provided above the cell to shield it. It is extremely difficult to do.

Therefore, even if the selective reflection layer or the diffusion transmission layer as described in the above publication is provided on the upper layer on the solar cell light-receiving surface side, due to the respective optical characteristics, the brightness, color tone and reflectance are -Various pattern lines with different sharpness enter the uniform color tone surface and are mixed and appear to float. Making these various pattern lines inconspicuous is the point to eliminate the discomfort in product design due to the mounting of solar cells, and the solar cell design lacks consideration to give the degree of freedom in product design design up to that point. It was In particular, in a "solar watch" or the like that can drive a movement with a solar cell electromotive force even in low indoor light conditions, there are severe requirements for designability. Furthermore, although the white type is the main, a selective reflection layer of various tones,
When a watch dial that also has a diffuse transmission layer is provided on the upper layer of the solar cell light-receiving surface, the gap must be close to the contact state due to the need for thinning. Even below, it is necessary to satisfy the above problems.

In addition, the solar cell module improves the battery performance by improving the power generation efficiency depending on the light source and illuminance to be used, and by increasing the voltage in accordance with the requirements of the device used due to the multi-stage integrated structure. On the other hand, it is a technology to expand the market of solar cells as clean energy, while having the freedom to design products that take into consideration the harmony with the products equipped with solar cells or the surrounding environment. It is an issue.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to have a highly efficient power generation capability, yet maintain a harmony in design, have no discomfort, and have a degree of freedom in design design. It is an object of the present invention to provide a solar cell module which is stable against environmental changes such as temperature and humidity and has high dimensional accuracy.

[0010]

The solar cell module of the present invention is an insulating ink for a solar cell having a color tone as close as possible to the color tone of the solar cell surface (which is almost determined by the interference color of the ITO transparent electrode thin film) and having a hiding property. The insulating pattern and electrodes exposed on the surface of the solar cell are covered with the ink of this color tone by patterning by a screen printing method or the like. Also, unlike the color tone of the solar cell surface, the same applies to the insulating pattern and conductive pattern that have high light reflectance, high light absorption rate, high light transmittance, and absorption in a specific wavelength range exposed on the solar cell surface. The above ink is overcoated by the same printing method or the like with a minimum thickness capable of maintaining the hiding property. As a result, the surface of the solar cell is unified to a uniform color tone, and unlike the high reflectance film formed by the dry process, the contrast that is visible with a pigment-dispersed ink film that has a large amount of diffuse reflectance component is also mitigated, and the tone of the design is harmonized. Is maintained.

To obtain a cell in which the surface of the solar cell has a uniform color tone as the lowermost layer and a "diffusion / transmissive layer" is provided in the upper layer on the light-receiving surface side, and a solar cell having an arbitrary color tone is obtained. A cell in which the diffuse transmission layer itself has a color tone or a "selective reflection layer" is provided as an upper layer of the "diffusion transmission layer" or an intermediate layer with the solar cell is effective.

That is, the above object is achieved by the following constitution. (1) A light receiving surface of a solar cell module having a photoelectric conversion unit that converts incident light into electricity, wherein the photoelectric conversion unit has silicon, and an insulating colored film is provided on a portion other than the photoelectric conversion unit. This insulating colored film has a reduced color difference from the photoelectric conversion part, has a color difference ΔE of 3.0 or less, and has a surface having a uniform surface color of the photoelectric conversion part. Module. (2) A light receiving surface of a solar cell module having a photoelectric conversion unit that converts incident light into electricity, wherein the photoelectric conversion unit has silicon, and an insulating colored film is provided on a portion other than the photoelectric conversion unit. This insulating colored film reduces the color difference with the photoelectric conversion part, and the color difference ΔE is 3.0 or less, and the upper layer of the light receiving surface of the solar cell module has a white or light color system. And a color difference ΔE between the insulating colored film and the photoelectric conversion unit, which is recognized through the diffusion / transmission layer.
A solar cell module having a value of 3.0 or less. (3) The diffuse transmission layer has a total light transmittance of visible light of 2
The solar cell module according to (2) above, which has 0% or more and a haze of 50% or more. (4) A light receiving surface of a solar cell module having a photoelectric conversion unit that converts incident light into electricity, wherein the photoelectric conversion unit has silicon, and an insulating colored film is provided on a portion other than the photoelectric conversion unit. This insulating colored film reduces the color difference with the photoelectric conversion part, and has a diffusion transmission layer of black or a color tone close to black in the upper layer of the light receiving surface of the solar cell module, A solar cell module in which the color difference ΔE between the insulating colored film and the photoelectric conversion part recognized through the transmission layer is 5.0 or less.
Le. (5) The diffuse transmission layer has a total light transmittance of visible light of 2
The solar cell module according to the above (4), which has a haze of 0 to 40% and a haze of 10 to 15%. (6) The solar cell module according to any one of (1) to (5), wherein the insulating colored film has pigment particles dispersed in a binder. (7) The above (1), (2), and (3) having a white fine particle pigment as the pigment particles dispersed in the insulating colored film.
Alternatively, the solar cell module of (6). (8) The solar cell module according to any one of (1) to (7), wherein the photoelectric conversion unit is a non-single crystal silicon film. (9) The solar cell module according to any one of the above (2) to (8), further having a selective reflection layer as an upper layer and / or a lower layer of the diffusion transmission layer. (10) The said photoelectric conversion part is a solar cell module in any one of said (1)-(9) which has a transparent conductive film. (11) The above (1) to (1), which has a base material of any of a resin having transparency and heat resistance, glass, and stainless steel.
The solar cell module according to any one of (10). (12) A hot-melt material having a buffer adhesive layer containing a thermosetting resin is laminated on at least one surface of a substrate having a light-transmitting property and heat resistance, glass, or stainless steel. (1) to (11) above
One of the solar cell module. (13) The base material and / or the buffer adhesive layer contains an ultraviolet absorber or is localized on the surface.
2) Solar cell module. (14) The solar cell module according to the above (12) or (13), wherein the buffer adhesive layer contains an organic peroxide. (15) The base film of the hot-melt material has a glass transition point of 65 ° C. or higher before thermocompression bonding, or a heat resistant temperature of 80 ° C. or higher, according to any one of (12) to (14) above. Solar cell module. (16) The base film of the hot-melt material has a degree of molecular orientation (MOR) of the base material before thermocompression bonding of 1.0 to 3.0, which is the sun according to any one of the above (12) to (15). Battery module. (17) The organic peroxide has a half-life of 10 before thermocompression bonding.
(12) to (1) whose decomposition temperature over time is 70 ° C. or higher
The solar cell module according to any one of 6). (18) The solar cell module according to any one of the above (1) to (17), which has a protective coating film having translucency and heat resistance on the photoelectric conversion part. (19) The above (12) is further formed on the protective coating film.
A solar cell module having the hot melt material layer according to any one of to (18). (20) A timepiece having the solar cell module according to any one of (1) to (19) above.

[0013]

[0014]

[Function] In the conventional solar cell, uniformization of the color tone, including the color tone portion of the fine line constituting each functional pattern indispensable for making the battery other than the color tone of the power generation layer, that is, the photoelectric conversion portion, has been studied. Absent. Therefore, in the method of providing a selective reflection layer having both diffusivity and transmissivity of incident light on the light receiving surface and a diffusive transmissive layer and ensuring power generation, each function pattern other than the color tone of the photoelectric conversion part is ensured. It was not possible to conceal by uniformizing the color tone including the color tone part. In the present invention, an insulating ink that is as close as possible to the color tone of the photoelectric conversion portion is prepared and used as it is as an insulating pattern film on the portion exposed on the surface of the solar cell. Alternatively, for an insulating pattern or a conductive pattern having high light reflectance, high light absorption rate, high light transmission rate, or absorption in a specific wavelength range, an ink hiding method in which an upper layer is overcoated is effective. is there.

In order to obtain a high-quality white-colored / light-colored surface-colored solar cell, a cell having a uniform color tone on the surface of the solar cell by the above-described ink hiding method is used as the lowermost layer. It is extremely effective to provide a diffuse transmission layer on the light receiving surface side or a selective reflection layer.

In the L ^* a ^* b ^* color system (representing lightness, reddishness and bluishness, respectively), the color difference ΔE between the photoelectric conversion portion and the portion other than the photoelectric conversion portion coated with the color-insulating ink. The value is set to 3.0 or less. Further, the surface color of the solar cell recognized through the diffuse transmission layer (mainly white filter) and the color insulation close to the surface color of the solar cell recognized through the diffuse transmission layer (mainly white filter). Color ink difference ΔE
The value is preferably 3.0 or less, more preferably 2.0 or less. In this case, the L ^* a ^* b ^* color system values of the reference solar cell surface color are (44.51, 6.4), respectively.
7, 2.24), and the L ^* a ^* b ^* colorimetric values of the surface color of the white filter used (diffuse transmission layer) are (6.
9.12, 0.93, 3.88). The total light transmittance (Tt) of the white filter was 47.9%, the diffuse transmittance (Td) was 33.8%, and the haze value was 70.6%.

As described above, in a solar watch using a general white dial, the color-insulating ink having a color close to the surface color of the solar cell is a rutile type titanium dioxide having a high hiding power as a pigment component of the current insulating ink. And a light-resistant brown pigment (such as red iron oxide) are particularly effective.

On the other hand, for outdoor applications, especially sports diver watches, solar watches of a design using a black dial are popular. In this case,
The diffuse transmission layer has a total visible light transmittance of 40 to 20.
%, The haze value is 10 to 15%, there is almost no diffuse transmittance, and the lightness L * is often as low as about 10 such as a black filter, which is a low lightness filter. When such a filter is provided on the light receiving surface side, the color tone of the filter itself is visually emphasized in a blackish color more than the color tone of the solar cell surface color visually recognized through the filter. For this reason, it is not necessary to take measures to make the battery surface color uniform as in the case of using a filter with high total light transmittance and diffused light transmittance in the above-mentioned white system, and through the black-based filter with low lightness, cell The reflected black color tone that is reflected by the photoelectric conversion film of is almost black, and the concealment ink color tone that is overlaid on the upper layer of the non-power generation film part of the solar cell is closer to it, because the visibility is less discomfort. Even if the ink color difference ΔE from the film is much more than 3.0, the black color tone of the black dial and extremely low transmittance (Tt: 2.6%, Td: 2 of the dial used as a typical example). 0.7%, haze value: 1
It was 0.7%. ), And because there is almost no light diffusion effect, the color tone of the return light reflected on the cell surface and recognized after passing through the filter (black dial) is only when such a black filter is used. The size of the color difference due to the difference in the parts in the cell largely depends on the optical properties of the panel), and it is almost irrelevant unless there is a high-reflectance metallic luster color part. Is recognized as

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The solar cell module of the present invention comprises:
A light-receiving surface of a solar cell module having a photoelectric conversion unit that converts incident light into electricity, wherein the photoelectric conversion unit has silicon and has an insulating colored film at a site other than the photoelectric conversion unit, This insulating colored film reduces the color difference with the photoelectric conversion part obtained by reflection of light containing at least light in the visible light region.

The photoelectric conversion section corresponds to a so-called power generation layer, and in a solar cell, it is usually a single crystal Si or a polycrystalline S.
i, or amorphous Si (α-Si),
A predetermined impurity is added to this to form a pn junction or pi junction.
The n-junction is formed.

The light receiving surface of the solar cell is a surface on which light necessary for light-to-electricity conversion is incident, and is usually a photoelectric conversion part or other structure except for a protective layer on the front side of the solar cell. Is referred to as the surface.

The parts other than the photoelectric conversion part refer to various structures or structure films required for the power generation function of the solar cell other than the photoelectric conversion part, such as an insulating pattern and a conductive pattern. , More specifically, a collecting electrode such as an Ag conductive film,
Ag (Cu, Cu compound, N
i, Mo, metal thin film and metal fine particle dispersion conductive film typified by Al), thin film or fine particle dispersion film by dry process of carbon black, graphitized carbon black, etc., and conductive mixture of the metal fine particles and carbon fine particles A film, a transparent electrode of ITO, ZnO, SnO ₂ or the like, a printed insulating film, or the like.

The insulating colored film reduces the color difference from the photoelectric conversion section. Specifically, the color difference ΔE is 3.0
Or less, preferably 2.5 or less, particularly 2.0 or less,
The lower limit is not particularly limited. That is, this insulating colored film is adjusted so that the color difference ΔE with the photoelectric conversion unit is 3.0 or less when the film formation surface is observed from the outside, together with the color and reflectance of the underlying portion. Further, a color insulating ink having a color close to the surface color of the solar cell is applied and formed. This color difference is applied and formed on the photoelectric conversion portion recognized through the diffusion transmission layer and the other portion when the diffusion transmission layer (mainly a white filter) is used together as described later. The color difference ΔE value of the insulating colored layer is 3.0 or less, preferably 2.0 or less, and particularly 1.5 or less.

Further, a conductive pattern as a portion other than the photoelectric conversion portion, more specifically, a comb-shaped collecting electrode such as an Ag conductive film, or Ag (Cu, Cu compound, Ni, as a peripheral wiring electrode) is used. A metal thin film and a metal fine particle dispersion conductive film typified by Mo and Al), a thin film and a fine particle dispersion film formed by a dry process of carbon black, graphitized carbon black and the like, and a conductive film in which the metal fine particles and carbon fine particles are mixed. The colors of the conductive films themselves may be adjusted so that the color difference with the photoelectric conversion unit falls within the above range.

The color difference ΔE is generally expressed in NBS units (National
Bureau Standards), L ^* , a ^* , b
^* Display system brightness on (JIS-Z8722, JIS-Z8727 tristimulus values x defined by, y, index can be calculated from z) L ^*, redness a ^*, blue b ^*, each, Differences ΔL, Δ between the part coated with the insulating colored film and the photoelectric conversion part
It can be obtained from a and Δb as follows. ΔE = [(ΔL) ² + (Δa) ² + (Δb) ² ] ^1/2

The smaller the value of ΔE, the closer the two are. Normally, when ΔE exceeds 3.0, the difference is clearly recognized, and when ΔE exceeds 12.0, it is regarded as a completely different kind of color.

The insulating colored film is preferably pigment particles dispersed in a binder. A pigment particle dispersion film that has a low reflectance and diffuses and reflects even when there is reflected light is particularly preferable.

The binder has some weather resistance,
It has light resistance and the like, and is not particularly limited as long as it has various structures necessary for the power generation function of the solar cell other than the photoelectric conversion part, or has good binding properties with the structural film and good dispersibility of the pigment particles. Not something. When a portion other than the photoelectric conversion portion is covered by patterning by the screen printing method, an oil-soluble resin is preferable from the viewpoint of good wettability with a dry lower layer of the film as compared with an aqueous emulsion. Examples of the oil-soluble resin include epoxy resins, particularly phenoxy resins, olefin resins, preferably polyethylene resins, polypropylene resins or polyisobutylene resins; and vinyl resins, preferably ethylene-vinyl acetate copolymer resins, vinyl chloride- Vinyl acetate copolymer resin or vinyl acetate resin or ethylene-vinyl chloride-vinyl acetate resin; acrylic resin, preferably methacrylic ester resin, polyacrylic ester resin, ethylene-ethyl acrylate copolymer resin or ethylene-methacrylic acid copolymer Polymerized resin, phenol resin, polyurethane resin, polyamide resin, polyester resin, ketone resin, alkyd resin, rosin resin, hydrogenated rosin resin, petroleum resin, hydrogenated petroleum resin, malein Acid resin; Butyral resin and; and hydrogenated terpene resins; terpene resin and chroman - indene resin; and the like, in particular, phenoxy resins, epoxy resins, urethane resins, saturated polyester resins and the like are preferable. These are weather resistance obtained by the crosslinking, mechanical strength as a composite material film in which the material is dispersed, and
Organic materials such as ink film or base film as a base, IT
It is a resin that is excellent in terms of the adhesive strength to thin films of inorganic materials such as O and α-Si, and the stability against environmental changes during long-term use, and has a large degree of freedom in designing the molecular structure, which is advantageous.
In addition, these resins (polymer materials) may be used alone or in combination of two or more.

The pigment particles are not particularly limited as long as a predetermined hue close to the hue of the material of the photoelectric conversion portion can be obtained, and one or more pigments having high hiding power and high coloring power. It may be adjusted using. Specifically, titanium dioxide, which is a white or nearly colorless fine particle pigment with high hiding power, zinc oxide, kaolin, clay,
Calcium carbonate, barium carbonate, calcium sulfate, barium sulfate, magnesium carbonate, silica, alumina, diatomaceous earth, etc., as well as red iron oxide, carbon black, fine particle graphite, Prussian blue, cobalt blue, phthalocyanine pigment, etc., which have high coloring power, are used in combination. It is preferable. In particular, when rutile-type titanium dioxide (TiO ₂ ) having a high hiding power and high whiteness is mixed, a pastel intermediate color close to a diffusive color tone of the color tone of the base color, which is effective for hiding the light receiving surface as the base, can be obtained. it can. This is particularly effective in achieving uniform color tone when a white or light color system having a total light transmittance of 30% or more is provided in the uppermost part of the diffusive filter layer.

Iron oxide fine particles having a coloring power are purple, when combined with the color tone of a solar cell having a structure in which an ITO transparent electrode is laminated on an amorphous silicon thin film or the like.
It is preferable because it has a wide selection range of color tones such as brown, red, and black, and has light resistance and weather resistance like titanium dioxide.

By controlling the color tone using such a coating film in which pigments or pigment particles are dispersed, incident light is appropriately diffused and reflected, which is advantageous for unifying the color tone of the entire cell. For example, in order to prevent a large contrast difference between the photoelectric conversion portion and the portion caused by the high reflectance of the metal-based colored thin film of the non-photoelectric conversion portion hidden by the mask pattern by the dry process, It is advisable to provide a pigment dispersion color tone control coating film on the uppermost side of the cell light receiving side by screen printing so as to cover it. Thus, when a diffuse transmissive filter is placed thereon, it can be visually recognized that the color tone difference from the photoelectric conversion site is effectively alleviated and the color tone of the entire cell is made uniform through the filter.

In addition to this, if necessary, carbon black, cadmium red, molybdenum red, chrome yellow, cadmium yellow, titanium yellow,
Chromium oxide, viridian, titanium cobalt green, ultramarine blue, Prussian blue, cobalt blue, azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, slene pigments, perylene pigments, perinone Pigments,
The tint may be adjusted using a conventionally known pigment such as a thioindigo pigment, a quinophthalone pigment, a metal complex pigment and the like.

For example, when single crystal silicon or polycrystalline silicon is used for a solar cell without providing a light diffusion layer on the uppermost portion, Prussian blue, cobalt blue,
Using a phthalocyanine-based pigment alone or as a main component pigment is effective for uniforming the color tone.

A dye may be used in place of or in combination with the above pigment, but it is preferable to use a pigment. As the dye, azo dye, metal complex dye, naphthol dye, anthraquinone dye, indigo dye, carbonium dye, quinone imine dye, xanthene dye, cyanine dye, quinoline dye, nitro dye, nitroso dye, benzoquinone dye, naphthoquinone dye, phthalocyanine dye, Examples thereof include oil-soluble dyes such as metal phthalocyanine dyes.

The average particle size of the primary particles of the pigment is 0.
It is about 01 to 0.8 μm. The amount of the pigment mixed with the binder is preferably 30 to 500 wt%, more preferably 50 to 380 wt%.

As a means for providing an insulating colored film, a color insulating ink obtained by dissolving and dispersing the above binder and pigment particles in a dispersion medium is applied to a predetermined area on the light receiving surface of the solar cell.
It may be applied by a screen printing method or the like. The thickness of the coating film is about 15 to 30 μm when the underlayer is other than the Ag paste electrode film having high reflectance, and about 10 to 25 μm when the underlayer is other than metal.

The dispersion medium is preferably one that can dissolve and disperse the above binder and pigment and does not dissolve or corrode the structure on the surface of the solar cell. Specifically, cyclohexanone, isophorone, γ-butyrolactone, N-methylpyrrolidone, terpineol, octane, isooctane, decane, isodecane, decalin, nonane, dodecane, isododecane, cyclooctane, cyclodecane, benzene, toluene, xylene, mesitylene, isoper. E, Isopar G, Isopar H, Isopar L (Isopar; trade name of Exxon), Shersol 70, Shersol 71 (Shellsol; trade name of Shell Oil), Amsco OMS, Amsco 460
Solvents (Amsco; trade name of Spirits), acetic acid esters such as butyl carbitol acetate, butyl cellosolve acetate and the like can be mentioned. These may be used alone or in combination of two or more. The amount of the binder and pigment added to the dispersion medium is about 40 to 180 wt%.

In addition to these, if necessary, a dispersant,
You may mix additives, such as a defoaming agent and a leveling agent. These additives are usually added in a total amount of about 20 wt% or less.

On the upper layer of the light receiving surface of the solar cell module,
A diffuse transmission layer may be provided in order to improve the display product and give a design effect. The diffuse transmission layer is usually a white resin plate as a main component, but it may be adjusted to a necessary color tone depending on the design, and may have fluorescence that emits blue, green, UV light or the like. The material is not particularly limited, but a transparent resin such as an acrylic resin, a methacrylic resin, a polycarbonate resin, a polystyrene resin, a polyester resin, or a polyacrylate resin can be used. Further, it is possible to preferably use a white filler or a resin obtained by miniaturizing the above, a transparent inorganic filler or an organic filler having a significantly different refractive index, or a uniformly dispersed fine air bubble. Further, it may have a light color tone to the extent that power generation is not hindered.

In particular, in a timepiece application where design is important, a dial or a diffuse transmission layer having a color tone close to black may be used as a dial. In this case, mix the required amount of carbon black, graphite and other fine particles,
It is only necessary to ensure a minimum light transmittance of 20% or more required for power generation.

When such a black dial having a low transmittance is used for the diffusion transmission layer, the color difference ΔE between the photoelectric conversion portion and the non-photoelectric conversion portion of the cell located thereunder is 3 or more or 6 or more. The effect on the uniformity of the color tone is weakened through the dial, but rather the non-photoelectric conversion part avoids the metallic luster color tone with high reflectance, and is covered with a black colored coating film with low reflectance like the dial. Although more effective, the above color difference is usually 5.0 or less. The diffuse transmission layer generally has a total light transmittance of preferably 20% or more, particularly 50% in the visible region.
It is preferably 70% or more, more preferably 70% or more, particularly preferably 50% or more, and particularly preferably 70% or more.
Here, “haze% = diffused light transmittance / total light transmittance ×”
100 ". The thickness of the diffuse transmission layer is 25-8.
It is about 00 μm.

In addition to the diffuse transmission layer, a selective reflection layer may be provided. The selective reflection layer, for example, for visible light,
450-480nm (blue), 550-580nm (yellow-green),
It selectively reflects or transmits light having a wavelength in the band of 590 to 620 nm (orange). The selective reflection layer has an effect of improving a display product and giving a design effect, like the diffusion / transmission layer. As the selective reflection layer, for example, an interference filter such as one having a dielectric multilayer film provided on a glass substrate, or one having a semitransparent Ag thin film provided on the uppermost layer and sandwiching the dielectric thin film, a dichroic filter, or the like. Examples of the filler for the mirror, the diathermy mirror (cold mirror), and the light diffusion layer include those in which a small amount of a colored pigment is dispersed. The thickness of the selective reflection layer is usually 10
It is about 0 to 1000 μm.

Next, the solar battery cell of the solar battery module of the present invention will be described. For example, as shown in FIG. 4, the solar battery cell of the present invention includes a substrate 1, a lower electrode 2, and a p
It has a silicon-containing layer 3 such as α-Si having an n-junction, a pin-junction, etc., an insulating layer 4, and a transparent electrode 5 such as ITO. In addition, the first element isolation layer 6 and the second element isolation layer 7
And a wiring electrode 8 and a lower lead electrode 9. Note that FIG. 4 is a partial cross-sectional view showing a configuration example of a solar battery cell.

In such a solar cell, the light incident on the photoelectric conversion portion through the transparent electrode 5 reaches the silicon-containing layer 3 and the electromotive force generated therein is generated by the lower electrode 2.
And a region that can be taken out through the transparent electrode 5. Further, the other parts refer to the insulating layer 4, the first element isolation layer 6, the second element isolation layer 7, the wiring electrode 8 and the like.
These parts do not contribute to power generation and are made of a material different from that of the photoelectric conversion part. For this reason, if these structural members are in a region that can be visually recognized from the outside, and if the difference is clear, it impairs the design control.
Therefore, by providing the above-mentioned insulating colored film on these portions and setting the color difference to a predetermined value or less, control and harmony in design can be secured.

Further, as shown in FIG. 5, for example, in a circular solar battery cell 21, a photoelectric conversion part 22 and an element for separating the photoelectric conversion part to form a series connection structure for increasing the voltage of the cell. The separating portion 23, the connecting portions 27, 28 and 29 having a wiring structure of serial connection, the extraction electrode portion 25,
Has 26. The element isolation section 23 is usually the photoelectric conversion section 2
It becomes a lighter color than 2, and the connection parts 27, 28, 29,
Extraction electrode parts 25 and 2 partially penetrated to the bottom surface
No. 6 has a metal color for the wiring electrode, which has a high reflectance when the conductive Ag paste is used. Even if such a structure exists in a portion that can be visually recognized from the outside, the control on the design is impaired. Especially when using solar cells for the dial of a watch, the requirements required for design are strict,
Further control and harmony are required. Therefore, by providing the above-mentioned insulating colored film also in these parts, the color difference can be made a predetermined value or less, and the control and harmony in design can be secured. When the reflectance of the base is high, such as in a metal portion, an ink film having a high hiding property, including overcoating, may be used, for example, a thick film of about 30 μm.

In the solar cell, after the insulating colored film is provided, a surface coating member or a sealing member is provided to protect the cell structural member from mechanical damage, oxidation, corrosion and the like. It is preferable. Among these protective members, it is particularly preferable to seal with a lamination film, and as a particularly preferable lamination film, the following sealing using a hot melt material can be mentioned.

In order to reduce the cost of the solar cell module, a transparent resin protective coating may be used in an allowable field in view of the balance with the environmental resistance of the cell. That is, for example, only the transparent insulating film of Japanese Patent Application No. 9-320476, which is obtained by thermosetting a phenoxy resin with a melamine resin, may be used as the protective film.

When lamination is performed and a lamination film layer is formed on the surface of the solar cell,
At least only the thick portion of the transparent laminated film base material (for example, 50 to about 100 μm) has the same effect as providing a gap between the outermost surface of the light receiving portion of the cell body and the back surface of the dial. As a result, the degree to which the color tone of the solar battery cell is transmitted and visually recognized through the dial is reduced by the light diffusion effect of the dial, which is advantageous. Therefore, in a solar battery cell having such lamination sealing, the significance of providing the insulating colored film is significant.

The hot melt material used in the present invention has a buffer adhesive layer containing a thermosetting resin on at least one surface of a substrate made of a resin having translucency and heat resistance.

By providing a buffer adhesive layer of a thermosetting polymer having rubber elasticity, which is a soft resin having a high cross-linking density between polymer molecular chains, on a resin base material, buffer adhesion against changes in temperature and humidity can be achieved. Since the rate of change in mechanical properties of the layer is small and the change is slow, the function as a buffer adhesive layer can be maintained for a long period of time. Further, the glass transition point Tg of the resin protective film is 65 ° C. or higher or the heat resistance or continuous use temperature is 8
Since a resin film having a light-transmitting property and satisfying one or both of 0 ° C. or higher is used, performance deterioration does not occur even when the temperature is increased by direct exposure to a light source such as sunlight.

As a resin base material having a glass transition point Tg of 65 ° C. or higher and / or a heat-resistant temperature of 80 ° C., which is transparent and heat-resistant, a polyethylene terephthalate film (T
Polyethylene naphthalate heat resistant film (Tg113 ° C); trifluorochloroethylene resin [PCT
FE: NEOFLON CTFE (manufactured by Daikin Industries, Ltd.)] (heat-resistant temperature 150 ° C.), polyvinylidene fluoride [PV
DF: Denka DX film (manufactured by Denki Kagaku Kogyo Co., Ltd.)] (heat-resistant temperature 150 ° C: Tg 50 ° C), polyvinyl fluoride (PVF: Tedlar PVF film (manufactured by DuPont)) (heat-resistant temperature 100 ° C), and the like, Tetrafluoroethylene-perfluorovinyl ether copolymer [PFA: NEOFLON: PFA film (manufactured by Daikin Industries, Ltd.) (heat resistant temperature 260 ° C), tetrafluoroethylene-hexafluoropropylene copolymer [FEP: Toyofuron film FEP Type (manufactured by Toray)] (heat-resistant temperature 200 ° C.), tetrafluoroethylene-ethylene copolymer [ETFE: Tefzel ETFE film (manufactured by DuPont) (heat-resistant temperature 150
C), AFLEX film (Asahi Glass Co., Ltd .: Tg83
C.)] and other fluorine-based films such as copolymers; aromatic dicarboxylic acid-bisphenol copolymerized aromatic polyester polyarylate films (PAR: casting (Kanebuchi Chemical Co., Ltd. Elmec) (heat resistance temperature 290 ° C .: Tg21
5 ° C), [polymethylmethacrylate film [PM
MA: Technoloy R526: Tg: 101 ° C (manufactured by Sumitomo Chemical Co., Ltd.)]; Polysulfone [PSF: Sumilite FS-1]
200 (Sumitomo Bakelite Co., Ltd.)] (Tg 190 ° C),
Polyether sulfone (PES: Sumilite FS-13
00 (Sumitomo Bakelite)] (Tg 223 ° C), etc., sulfur-containing polymer film; polycarbonate film [P
C: Panlite (manufactured by Teijin Chemicals)] (Tg 150 ° C.);
Functional norbornene-based resin [ARTON (Japan Synthetic Rubber)] (heat-resistant temperature 164 ° C: Tg 171 ° C);
Polymethacrylate resin (PMMA) (Tg 93 ° C);
Olefin-maleimide copolymer [TI-160 (manufactured by Tosoh Corporation)] (Tg 150 ° C or higher), para-aramid (Aramica R: Asahi Kasei) (heat-resistant temperature 200 ° C), fluorinated polyimide (heat-resistant temperature 200 ° C or higher), polystyrene (Tg9)
0 ° C.), polyvinyl chloride (Tg 70 to 80 ° C.), cellulose triacetate (Tg 107 ° C.) and the like.
Among them, polyethylene naphthalate heat-resistant film (Tg1
13 ° C) has a heat resistance (Tg) when compared with PET,
Long-term heat resistance, Young's modulus (stiffness), breaking strength, heat shrinkage, low oligomers, gas barrier properties,
It has excellent performance in terms of hydrolysis resistance, water vapor transmission rate, thermal expansion coefficient, physical property deterioration due to light, etc., when compared with other polymers, breaking strength, heat resistance, dimensional stability, moisture permeability, It is preferable because it is excellent in terms of total balance such as cost.

The glass transition point Tg of the resin base material is 65 ° C. or higher, preferably 70 ° C. or higher, more preferably 80 ° C. or higher, especially 110 ° C. or higher. The upper limit is not particularly limited, but is usually about 130 ° C. Is. The heat-resistant temperature or continuous use temperature is 80 ° C or higher, preferably 100 ° C.
Above, in particular, 110 ° C or higher is preferable, and the higher the upper limit, the more preferable, and it is not particularly limited, but usually 250
It is about ℃. The thickness of the resin base material is appropriately determined depending on the member to be laminated, required strength, bending rigidity, etc., but is usually in the range of 5 to 100 μm, preferably 20 to 90 μm. When the film thickness of the resin base material is less than 5 μm, it becomes difficult to obtain the effect of surface protection, and the hot melt material is deformed after the adhesive layer is applied. When the film thickness exceeds 100 μm, the film containing fine particles of Al ₂ O ₃ , SiO ₂ or the like has a low light transmittance and a poor laminating property in a roll state, which makes continuous production difficult. Further, the rate of change in dynamic elastic modulus at 0 ° C. and / or 120 ° C. after thermocompression bonding is preferably within 30%, more preferably 20%.
It is preferably within. The absolute value is 1 × 10 ⁹ to 1 × 1.
0 ^{1 2} dyn / cm ² range are preferred. When the rate of change in the dynamic elastic modulus at 0 ° C. or 120 ° C. after thermocompression bonding exceeds 30, internal stress acts beyond the buffer action of the buffer adhesive layer, resulting in a decrease in adhesive force, peeling of hot melt material, and laminate. Is likely to be deformed.

It is to be noted that having translucency means transmitting 70%, preferably 80% or more of light in the visible light region.

The resin base material has a MOR indicating the degree of molecular orientation.
The value (Molecular Orientation Ratio) is preferably 1.0 to 3.0, more preferably 1.0 to 2.0, and particularly preferably 1.0 to 1.8. When the MOR is within the above range, the deformation of the laminate is reduced. The MOR value indicating this degree of molecular orientation is, for example, Compatech 1998.3.
"Quality control of films and sheets using microwave molecular orientation meter" Shigeyoshi Osaki, Seikei-Kakou Vol7 No11 1995
"Molecular orientation behavior associated with biaxial distraction" Yasunobu Zushi, Takahiro Niwa
It is described in documents such as Sadao Hibi, Shin'ichi Nagata and Tachi.
The larger the MOR value, the larger the anisotropy, and 1.0 indicates the most isotropic.

Regarding the degree of molecular orientation, the MOR value may differ depending on the site even for the same resin film. In particular, in the film produced by the biaxial stretching method, the degree of orientation tends to increase at the end portion held for stretching. Therefore, even if the resin has a high degree of molecular orientation, it is preferable to inspect each portion of the resin film to be used for the degree of molecular orientation, and confirm that the degree of orientation is within the above range before using.

The MOR can be obtained, for example, by measuring the transmitted microwave intensity while rotating the sample. That is, the interaction between the microwave electric field of a certain frequency and the dipole that constitutes the polymer substance is related to the inner product of the vectors of both, and when the sample is rotated in the microwave polarized electric field, the dielectric constant is Due to the anisotropy of
The transmitted microwave intensity changes, and as a result, the degree of molecular orientation can be known. As the microwave used for measurement,
Although not particularly limited, for example, 4 GHz, 12 GHz
Etc. As a measuring instrument applying such a principle, for example, a molecular orientation meter MOA-50 manufactured by Shin Oji Paper Co., Ltd.
01A, 5012A, MOA-3001A ・ 3012A
Etc. In addition to this, it can also be determined by X-ray diffraction, infrared dichroism, polarized fluorescence method, ultrasonic method, optical method, NMR method and the like.

It is preferable that the degree of molecular orientation be within the above range for the constituent material of the object to be laminated using a hot melt material, such as a flexible substrate.

As the thermosetting resin component of the buffer adhesive layer containing the thermosetting resin and the organic peroxide, ethylene-vinyl acetate copolymer [EVA (vinyl acetate content of 15 to 5 is included.
0%)].

Any organic peroxide may be used as long as it decomposes to generate radicals at a temperature of 80 ° C., particularly 90 ° C. or higher, and the half-life time is taken into consideration when the stability during compounding is taken into consideration. It is preferable that the decomposition temperature for 10 hours is 70 ° C. or higher. Examples of such thermosetting organic peroxides include 2,5-dimethylhexane-2,5-dihydroperoxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane. -3; di-t-butyl peroxide; 2,5-dimethyl-2,5-di (t
-Butylperoxy) hexane; dicumyl peroxide; α, α'-bis (t-butylperoxyisopropyl) benzene; n-butyl-4,4-bis (t-butylperoxy) valerate; 2,2- Bis (t-butylperoxy) butane; 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane; t-butylperoxybenzate; benzoyl peroxide and the like, One or two of these
You may use it in combination of 2 or more types, and the compounding ratio in that case is arbitrary. The polymerization component 1 of the thermosetting organic peroxide
The compounding ratio to 00 parts by weight is preferably 10 parts by weight or less, more preferably 0.5 to 6 parts by weight.

Further, an ultraviolet absorber may be added if necessary. By adding the ultraviolet absorber, it is possible to prevent the ultraviolet light resistance of the film itself and the phenomenon of deterioration of the thin film such as α-Si constituting the photoelectric conversion part due to light. Particularly, when the polymer film is arranged on the light-receiving surface side, a benzophenone-based or benzotriazole-based UV absorber having an ultraviolet light-shielding function is typified by the light-receiving surface side surface or the inside of the polymer, and further represented by crosslinkable EVA. It is advisable to perform surface treatment, mixing, or mixing with such a buffer adhesive layer.

As the ultraviolet absorber, various aromatic organic compounds can be used. Particularly, the one represented by the following chemical formula 1 is advantageous because it does not cause yellowing and bleed-out on the film surface even after long-term use. is there. Among these, benzotriazole type is particularly preferable. Alternatively, zinc oxide (ZnO) fine particles may be used in the same manner as a chemically stable inorganic ultraviolet absorber.

Further, perhydropolysilazane (Mn = 6
00-2000) xylene solution (N-V manufactured by Tonen K.K.)
ZnO particles are dispersed in 120) and coated on the polyethersulfone resin film to a thickness of about 0.5 μm, and steam oxidation is performed at 90 ° C. (80% RH) for 1 hour (5% trimethylamine as a catalyst). (Use of aqueous solution), when forming a dense transparent silica thin film at low temperature, SiO ₂ / Zn
ZnO was added so that O = 45/55 (weight ratio),
When this is provided as the transparent base material on the uppermost portion on the light receiving surface side of the solar cell, it is effective for improving the UV resistance of the inorganic UV protection film and for improving the outdoor weather resistance of the cell as a protective film.

[0063]

[Chemical 1]

If necessary, additives such as a curing accelerator may be added. For example, when a hot melt material is laminated on a member to be laminated, an organosilane compound represented by a structure such as RSi (OR) ₃ (R: C ₂ H ₅ ) is used as a defoaming agent and a defoaming agent for a buffer adhesive layer. It is also effective to add 6 parts by weight or less of the above compounding ratio. This thing is heated
In the pressurizing step, it reacts with the organic peroxide (generates a free radical), becomes a cross-linking agent of the ethylene acetic acid copolymer as a main component, and is incorporated into the buffer adhesive layer. In addition, when the hot-melt materials are stacked or rolled and stored, the buffer adhesive layer has a function of preventing adhesion between the back surface of the substrate and facilitating peeling.

The thickness of the buffer adhesive layer may be adjusted to an optimum thickness depending on the organic peroxide to be used, the use environment, the member to be laminated, etc., and is not particularly limited, but preferably 3 to 500 μm, More preferably 3 to 50 μm,
Particularly, the range of 10 to 40 μm is preferable. If the thickness of the buffer adhesive layer is less than 3 μm, it becomes difficult to obtain the buffer effect, and if the thickness exceeds 500 μm, the light transmittance decreases, and burrs are likely to occur during punching. However, since the adhesive layer has much higher transmittance than the above-mentioned base material, it can be used up to 10,000 μm when used under high illuminance such as outdoors. The dynamic elastic modulus of the buffer adhesive layer after thermocompression bonding is preferably 5 × 10 ⁹ dyn / cm ² or less at 20 ° C.,
1 × 10 ⁶ dyn / cm ² or more at 100 ° C, especially 1 × at 20 ° C
10 ⁹ to 1 × 10 ⁶ dyn / cm ² , 2 × 10 ⁶ to 1 at 100 ° C.
The range of × 10 ⁹ dyn / cm ² is preferable. In addition,
The maximum peak value of tan δ preferably appears at 20 ° C or lower, and particularly preferably in the range of -100 to + 15 ° C.

The buffer adhesive layer is usually provided only on one surface of the resin substrate, particularly when it is used as a laminate protective film. Further, as will be described later, when the solar cell substrate and the laminate film base material are different from each other and a large difference in thermal contraction rate at the time of temperature rise occurs, it may be provided on both front and back surfaces for flattening the cell. By providing on both sides in this way, it is also advantageous for outdoor use in a severe environment. When it is used as a bonding means in the manufacturing process of an optical recording medium or a flat panel display described later, it is provided on both sides of the resin base material. In that case, it is preferable that the thickness of the resin base material or the buffer adhesive layer is thin within the above range. Alternatively, the buffer adhesive may be used alone as a sheet unit having a thickness of 4 to 6 mm.

As a means for providing the buffer adhesive layer on the resin base material, a known method such as coating or extrusion coating can be provided. The total thickness of the buffer adhesive layer and the resin base material is preferably 10 to 600 μm, more preferably 10
~ 120 µm, more preferably 30-90 µm, especially 60-8
The range of 0 μm is preferred.

The hot melt material used in the present invention may be one in which the buffer adhesive layer is embossed or has a grain. This embossing or grain is
The hot-melt material of the present invention is particularly preferably provided when pressure-laminated, and it is preferable that the hot-melt material is provided in a streak shape in the same direction as the conveying direction during lamination. When used for bonding, the direction is arbitrary, but the optimum direction may be selected depending on the bonding direction and the bonding. By providing embossing or embossing, a bubble escape path is formed, and the inclusion of bubbles is reduced. In particular, when pressure lamination is performed with a roll laminator, when the laminate film is held by a roll of a roll laminator and nippled with a material to be laminated, bubbles are likely to escape along the laminating direction. The size, spacing (or density), etc. of embossing or embossing are not particularly limited, but, for example, Ra = 0.4 to 10 μm,
The range of 0.6 to 0.8 μm, the average spacing between peaks and peaks of 50 to 180 μm, and particularly 60 to 140 μm are preferable. The means for providing the texture is not particularly limited, but it may be embossed or once processed into a release film and then transferred.

Next, a method of manufacturing the solar cell module will be described. A buffer adhesive layer is formed on the upper surface (light receiving surface) of a member to be laminated such as a solar cell sheet or a surface to be protected, and on at least one surface of a resin base material having a glass transition point Tg of 65 ° C. or higher and having a light-transmitting property and a heat resistance. And a buffer adhesive layer of the above-mentioned hot melt material are combined, and thermocompression bonding is performed by a roll laminator or the like, preferably at a temperature of 100 to 120 ° C. and a linear pressure of 20 to 70 g / cm. Although the case of single-sided laminating is described here as an example, double-sided laminating may be used depending on the member to be laminated and the operating environment. In that case, the buffer adhesive layer should be sandwiched between the members to be laminated up and down. Then, it may be thermocompression bonded by a roll laminator or the like.

[0070] The resulting composite sheet was cut into a predetermined size, housed in a container equipped with a heating and pressing means such as an autoclave, preferably dry air or N _2, in particular N ₂ atmosphere, further preferably The direction perpendicular to the plane of the composite sheet,
In other words, 0.01 to 5.0 kg almost uniformly from the top and bottom,
Mechanical pressure of 0.1 to 5.0 kg is applied, and 70 ° C or higher, particularly 140 to 180 ° C (pressure during heating 3 to 15 kg
/ Cm ² ) to heat and press for 30 to 120 minutes to thermally crosslink and defoam, and improve the adhesion to obtain the laminate of the present invention. In this case, the heating temperature by the heating / pressurizing means and the hydrostatic pressure can be arbitrarily adjusted by the member to be laminated or the hot melt material, and the timing of applying the mechanical pressure is also arbitrary, but the mechanical pressure is preferably after heating. It is preferable to hold until cooled to room temperature. In particular, it is higher than the curing temperature of the adhesive layer, more preferably 70
Hold at ~ 100 ° C, pressurize at 5 ~ 10kg / cm ² , and press 1
After holding for 5 to 60 minutes to defoam, the temperature is not lower than the curing temperature of the adhesive, more preferably 100 to 170 ° C., and particularly 120 to 1
70 ° C., 3 to 15 kg / cm ² , especially 5 to 10 kg / cm ²
It is preferable to hold for 5 to 60 minutes, especially 15 to 60 minutes to thermally cure.

By laminating using a roll laminator in this way, the influence of unevenness on the member to be laminated, such as fine patterning of comb-shaped electrodes of solar cells or fine patterns for insulation between cells, can be avoided. It becomes difficult to receive. That is, when the buffer surface adhesive layer which is heated with the structural surface on the member to be laminated and has increased fluidity is sent while being nippled by the elastic roll of the roll laminator,
The bubbles, which tend to remain in the shadow of the pattern on the structure surface, are efficiently pushed out by receiving the hydrodynamic force due to the shear stress generated between the elastic rolls.

Bubbles that cannot be completely removed by the roll laminator are defoamed in the thermal crosslinking step by the heating and pressurizing means. At that time, preferably, a heat-resistant elastic member sheet is laminated on the upper surface (light-receiving surface) of the composite sheet,
Further, a metal plate is laminated on it, and several metal plates are laminated, and a pressing means such as an air cylinder is provided in the vertical direction (via a flat plate having high rigidity such as a SUS plate and having high rigidity) as described above. It is preferable to apply pressure mechanically. As a result, the module, which has been arbitrarily deformed by heat shrinkage and internal stress of various functional thin films laminated on the plastic substrate or the like, is laminated, and the device is smoothed and flattened.

As described above, by applying mechanical pressure as a laminated structure as described above in the thermal crosslinking step by heating and pressurizing, for example, as in a solar cell, α-Si, ITO,
It has rigidity and thickness of a plurality of different components such as Al alloy, interlayer insulating film, sealing insulating protective film, etc. By integrating these layers, heat shrinkage rate of each layer at the time of final film formation, internal Random deformation of the composite sheet having different stresses can be easily corrected. Moreover, since a plurality of composite sheets are laminated, a large number of flattening corrections can be performed simultaneously, which is advantageous for mass production. Further, even when compared with coating and the like, the surface is very flat and the smoothness is extremely good, and a product having an excellent appearance can be obtained, and the product can be preferably used for high value-added products and the like.

In addition, although the base material, the laminated member, and the like occupy most of the members that control the thickness of the device in the integrated laminated body, a metal such as SUS having a high rigidity of at least about 100 μm is used. The same flatness and smoothness as when using a glass substrate can be obtained. For this reason, it is possible to perform punching by a simple air press working as compared with a sheet body using these metal base material or glass base material, and through hole processing by YAG laser can be easily performed. You can Therefore, the productivity is much higher than that of the sheet body using the metal base material or the glass base material, and the thin film device can be precisely processed by a simple means, which leads to cost reduction in mass production. I can contribute. Also, by combining with patterning using the screen printing method, it is possible to quickly respond to device design changes and the like, and the cost is reduced.

The heat-resistant elastic member sheet to be laminated is not particularly limited as long as it can withstand the above heating temperature, and can be appropriately selected and used from known heat-resistant elastic members. As such an elastic member,
Heat resistant silicone rubber, fluoro rubber (Viton)
Examples thereof include fluorosilicone rubber. The thickness of this elastic member sheet is not particularly limited, but is usually 0.5.
It is in the range of 10 mm.

Examples of the metal plates to be laminated include aluminum, SUS, brass, steel plates and the like, but aluminum is particularly preferable because it is lightweight and has good thermal conductivity. Although the thickness of the metal plate is not particularly limited, it is usually 0.
The range is 2-3 mm. These metal plates may be subjected to surface treatment such as alumite processing or plating of chrome, nickel, nickel chrome, coating, etc. by known means.

In the solar cell module of the present invention,
In order to reduce the cost, a coating film having light resistance and weather resistance may be provided on the surface of the solar battery cell instead of the hot melt material. Although such a resin coating film is slightly inferior in terms of flatness, weather resistance and the like to the one subjected to the hot lamination described above, the laminating step and the flattening step can be omitted, the manufacturing cost can be reduced, and the mass productivity can be improved. Is improved. In particular, it is suitable for being incorporated in equipment or used mainly for indoor applications.

As such a resin coating film, transparency, toughness, adhesion to a transparent electrode or the like, surface hardness, heat / cold resistance, low moisture absorption, low gas barrier property, etc. It is preferable that the characteristics are well balanced and excellent. In particular, 2000-3000 (M
In order to maintain the mechanical strength of the coating film with a molecular weight of about n or less, a main component resin capable of exhibiting the above-mentioned properties is used at a temperature of 200 ° C. or lower, which is a heat resistant temperature of a plastic substrate, and a melamine resin. , A non-yellowing modified isocyanate compound (a low temperature curable blocked isocyanate obtained by blocking the isocyanate group of the non-yellowing modified isocyanate compound with an active methylene group of acetylacetone (duranate "MF-K
60X "(manufactured by Asahi Kasei Co., Ltd.), a low-temperature curable blocked isocyanate blocked with MEK oxime, etc., and the like, and a thermosetting resin that is polymerized by a crosslinking reaction are preferable. The thermosetting resin is excellent in transparency and has little discoloration due to aging and light deterioration.

For example, as the fluorine-based resin, ethylene trifluoride, tetrafluoroethylene, and the H portion of the ethylene chain are
By condensation of Lumiflon resin (Asahi Glass), which is a copolymer with -OR, -OH, and -ORCOOH-substituted vinyl monomers, aliphatic, alicyclic polyesters, polyether prepolymers, and non-yellowing isocyanate compounds Polyurethane resin (eg Nippon Polyurethane PTM
G / Coroney HX cured product), a saturated polyester resin (copolymer of esters such as ethylene glycol, neopentyl glycol, phthalic acid and adipic acid: for example Toyobo Byron), a non-yellowing isocyanate, a cured product of melamine and the like. , Epoxy resin (for example, oiled shell Epicoat: 1009) and phenoxy resin (UCC: P
Preferred examples thereof include a cured product of KHH) with the above curing agent, a partially saponified acrylic polyol, and a phosphazene monomer (Idemitsu: PPZ monomer) having a polymerization-reactive functional group, which is cured by the non-yellowing modified isocyanate. You can

The coating film may be formed by coating, screen printing, spin coating or the like.

[0081]

EXAMPLES Example 1 [Preparation Method] As shown in FIG. 1, a lower electrode layer 2, an amorphous silicon layer 3 having a pn junction, a pin junction, etc., an insulating layer 4, ITO on a flexible substrate 1. Through holes 10 and open grooves 10a were formed by laser processing on the solar cell element body on which the transparent electrode layer 5 was formed.

Next, as shown in FIG. 2, the first element isolation layer 6 is formed on the ITO transparent electrode 5 having the groove 10a formed therein.
Then, a second element isolation layer 7 was formed, and a wiring electrode layer 8 was further formed on the first element isolation layer 6 and the through hole 10 as shown in FIG.

Next, as shown in FIG. 4, after forming a lower lead-out electrode 9 if necessary, on the above-mentioned wiring electrode 8,
Color adjusted by the following color insulating resin composition 1
An insulating ink was applied to form an insulating colored film 11.

Color close to the surface color of the solar cell photoelectric conversion section
If the insulating resin composition 1 is the solar battery cell of FIG.
Insulating film (primary printing resin) 4, element isolation layers 6 and 7 (secondary printing resin) exposed on the surface of the solar cell, Ag of wiring electrode 8
Paste (to suppress high light reflectance of the electrode) It is used by overcoating on the electrode. The details will be described below.

Color-Insulating Resin Composition 1 Phenoxy Resin (UCC: PKHH Mn = 15400) 14 parts by weight Cyclohexanone 15 parts by weight Isophorone 15 parts by weight Rutile-titanium dioxide (Ishihara Sangyo Co., Ltd .: average particle diameter 270 nm) 32 15 parts by weight Bengala (manufactured by Toda Kogyo Co., Ltd .: average particle size 300 nm) 15 parts by weight Dispersant (oleic acid) 3 parts by weight Defoaming agent (TSA-720 manufactured by Toshiba Silicone) 1 part by weight Leveling agent (KS-made by Shin-Etsu Silicone) 66) 1 part by weight of phenoxy resin was completely dissolved in a mixed solvent (cyclohexanone / isophorone) and dispersed together with titanium dioxide, red iron oxide and a dispersant by a zirconia ball mill for 48 hours. Then, a defoamer leveling agent was added and mixed for another 2 hours.

Then, the following thermal crosslinking reaction components were added,
The mixture was further dispersed for 20 minutes to obtain a resin composition for a color insulating film.

5 parts by weight of n-butylated melamine resin (manufactured by Mitsui Toatsu Chemicals: Uban 21R) Curing accelerator (made by Mitsui Toatsu Chemicals: Catalyst 6000) 0.03 parts by weight Insulating resin composition obtained Insulating layer 4 shown in FIG.
After primary printing with a 150-mesh stainless screen on top, it was heat cured for 10 minutes in an oven at 160 ° C. Next, the ITO transparent electrode layer 5 was formed on this insulating film by Ar gas sputtering. In this sputtering process, no damage was observed on the insulating film, and a uniform I
The TO transparent electrode layer 5 could be laminated.

Next, color-insulating ink was applied to the first and second element isolation layers 6 and 7 shown in FIG. 2 and the wiring electrode 8 shown in FIG. 4 by using a 150-mesh stainless screen. Printed and heat cured in an oven at 160 ° C. for 10 minutes. As described above, the color insulating ink is applied on the insulating film 4, the element isolation layers 6 and 7 or is overcoated to suppress the high light reflectance of the wiring electrode 8 due to the Ag paste. By covering the entire surface of the solar cell except the conversion part, a flexible amorphous Si solar cell having a color almost equal to the surface color of the photoelectric conversion layer was obtained.

Next, a lamination film was prepared by laminating a buffering adhesive on a PEN film having a good transparency and a good physical strength including environmental reliability, and laminating the lamination film on the light receiving surface of the solar cell. It was stopped.

That is, a PEN film (Tg: 113 ° C.) having a thickness of 50 μm was prepared as a flexible film base material having translucency and heat resistance. Further, as a buffer adhesive layer, ethylene-vinyl acetate copolymer resin (EVA: vinyl acetate content is about 15 to 50% by weight), dicumyl peroxide as an organic peroxide, EVA100 described above.
7 parts by weight with respect to 7 parts by weight of a curing agent was further mixed with a small amount of an additive such as a curing accelerator, and the mixture was applied to one surface of the resin film substrate to a thickness of 20 μm. , A buffer adhesive layer was used.

After laminating, a flattening treatment was carried out to a level satisfying the specifications of watch parts, and a film solar cell corresponding to a watch dial could be obtained.

Even if the laminate sealing is not performed, the reliability of the cell is secured to some extent, and the above process is simplified, and a transparent protective coating film having light resistance is simply used to form the surface on the cell light receiving surface side. May be covered. Thus, by protecting the surface only with the coating film, the cost of the solar cell can be reduced and the solar cell can be provided at low cost.

Next, on the flexible solar cell having the uniformed color tone, a white watch dial (material: acrylic resin, alumina, alumina, etc.) having optical functions of a diffusion transmission layer and a selective reflection layer was formed. A plastic plate in which ultrafine particles were dispersed, a thickness: 500 μm, and a total light transmittance: 52%) was assembled into a solar watch with almost no gap between the solar cells.

Comparative Example A solar battery cell was obtained and a solar watch was assembled in the same manner as in Example 1 except that the color-insulating resin composition 2 having the following composition was used.

[0095] Color-insulating resin composition 2   20 parts by weight of phenoxy resin (UCC: PKHH Mn = 15,400)   Cyclohexanone 40 parts by weight   Isophorone 30 parts by weight   High resistance carbon black (manufactured by Degussa: average particle size 25 nm) 4 parts by weight   Aerosil (manufactured by Degussa: average particle diameter 15 nm) 10 parts by weight   Dispersant (oleic acid) 3 parts by weight   Defoaming agent (Toshiba Silicone: TSA-720) 1 part by weight   Leveling agent (Shin-Etsu Silicone: KS-66) 1 part by weight

[Evaluation Method] A flexible solar battery cell having a uniform color tone of the photoelectric conversion part and a solar watch integrated with a white watch dial, and a solar battery cell of a comparative example,
Solar watch and white watch dial High-speed colorimetric spectrophotometer (CMS-35, manufactured by Murakami Color Research Laboratory Co., Ltd.)
sp) was used to measure the "tristimulus value" and the "L ^* a ^* b ^* color system (each showing lightness, redness, and blueness)".

Regarding the clock dial, JIS-K-73
In accordance with No. 61, the total light transmittance was also measured, and a comparative examination was performed with the visual evaluation under natural light and under a fluorescent lamp.

[Results] 1) The solar cells prepared in Examples, the solar cells of Comparative Examples, and the solar watches of Examples and Comparative Examples were subjected to color measurement by the above evaluation method. From the L ^* a ^* b ^* value, the surface color of the photoelectric conversion part and the reflection color color difference value ΔE with respect to the incident natural light of the insulating resin layer prepared in the example were calculated, and the value was 2.39. . This value was a color tone at a limit level that could be used as a clock dial or a portable solar cell as a cell in which the surface color of the power generation film was made uniform as it was.

2) In the solar watch prepared in the example, the result of calculating ΔE of the color difference value of the reflected color in order to compare with the color tone with respect to the incident natural light through the white clock face of general-purpose level The value was 0.16 and was in the range of 0.2 or less in NBS unit. Even by visual observation, including the element separation part 23 (cross pattern), the connection parts 27, 28, 29 and the take-out electrode parts 25, 26 (circumferential part pattern), including the particularly noticeable color difference parts It was at a level where the existence of solar cells in

3) The ΔE value of the solar cell prepared in the comparative example was 34.86, and the ΔE value was 12 or more in NBS unit even for the solar cell with the white-based clock dial. The cross pattern, such as the circumferential pattern, was clearly recognized, and it was confirmed that the problem was great from the viewpoint of design.

4) In the solar watches produced in the examples, in order to compare with the color tone for incident natural light through a special black-based timepiece dial for diver's watches used outdoors, ΔE of the color difference value of the reflected color was measured. Calculated. The resulting value was 3.35, in the range above 0.3 in NBS units.

Even by visual observation, the element separating portion 23 (ten o'clock pattern), the connecting portions 27, 28 and 29, and the extraction electrode portion 2
5, 26 (circumferential pattern) and the like were coated with the color ink of the color insulating resin composition 2 used in the comparative example by a screen printing method including a black color ink film including the overcoat layer.

This color ink film had a color difference ΔE with the photoelectric conversion portion of 12 or more as shown in the comparative example of Table 1.

However, the special black clock dial used is
The total light transmittance measurement according to JIS-K-7361 was extremely low at 26.0%, and the diffuse light transmittance was 2.7%, which showed almost no shielding and hardening of reflected light due to light diffusion of the filter, and a haze value of 10 as well. It was as low as 4%.

If such a black dial is used, the loss of the amount of light that can be used to guarantee the operation of the solar watch is extremely large, which is disadvantageous to the power generation efficiency of the cell. However, it is advantageous in terms of design as a black dial for sports use, and using a black color ink film, ΔE is 3.3.
Although it exceeded 5 and 3.0, the non-power generation site by visual observation was not so noticeable. By the way, in the same manner as the standard cell when a black special dial having the above-mentioned low transmittance and low haze is added by covering the non-power generation portion with the ink film of the color insulating composition 1 of the example used in the white dial, The color difference ΔE was 2.50, which was larger than that of the color-insulating resin composition 2. This has been confirmed to be advantageous for enhancing the black color in terms of design, when using a dial having such special optical characteristics.

In the cell having the appearance shown in FIG. 5, in addition to the cell having the above-mentioned structure, the above-mentioned perhydroxypolysilazane was steam-oxidized to form a silica film (ZnO: containing a UV blocking agent) 14 on a transparent 75 μm thick PEN film 1. And a transparent conductive film ITO (15), ZnO (17), α-
A cell having a transparent film substrate back surface integrated structure that constitutes a solar cell was manufactured by stacking Si (13), a ZnO transparent conductive film (for the purpose of confining light) 18, and Al (metal base electrode) 12. The sectional structure is shown in FIG. In addition,
Japanese Patent Application No. 9-320476, in which the phenoxy resin is thermoset with a melamine resin in order to protect the Al base electrode 12.
A transparent protective film such as the transparent insulating film, or a laminate film may be disposed thereunder.

As a measure for producing such a cell,
When forming each thin film, it is covered with a metal mask and patterned by sputtering or plasma CVD. No patterning was done by laser scribing or screen printing.

However, as shown in FIG. 5, this cell also has a high reflectance due to the metallic luster of the lowermost Al electrode when viewed from the light-receiving surface side, the crosshairs are particularly conspicuous, and the contrast with the power generation site is further increased. Even if I put the dial on it, I couldn't cover it up.

Therefore, the ink film of the color insulating resin composition 1 used in the example is covered from the upper side (light receiving side) of the PEN film along the portion of the Al electrode having a high reflectance such as a crosshair (screen printing). (With patterning method)
It was effective in improving the design when the dial was placed.

5) JIS-based white dial used
The total light transmittance measurement according to K-7361 is 52.3.
%, Diffused light transmittance 32.5%, haze value 62.2
%, The amount of light was sufficiently secured as an indoor solar watch to ensure operation.

6) From the L ^* a ^* b ^* values, the surface color of the power generation film and the color difference value ΔE of the cell color tone ink were kept within 2.0, and the surfaces other than the power generation film were covered with this ink to make the surface color uniform. It was confirmed that it is possible to obtain a solar watch, a portable solar cell, and the like, which have no design problems, by using a filter (a dial) for the solar cell. The above results are shown in Table 1.

[0112]

[Table 1]

As described above, in the example of the "solar watch" in which the light-colored "clock face" mainly consisting of white is provided in the upper layer of the solar cell and the design is severe, the exposed surface of the solar cell is With a structure that provides a uniform color tone cell that is as close to the surface color as possible, the color difference value ΔE of the cell color tone ink and the cell of the color tone ink that is recognized by the sunlight is recognized through the white clock dial and is 2 in NBS units. By using "ink", "cell", and "filter- (clockface)" within the range of 0.0 or less, it was possible to obtain a "solar watch" having no problem in design.

<Example 2> A solar cell module was obtained in the same manner as in Example 1 except that the resin film having the following composition was applied to the cell surface instead of the lamination film. When evaluated in the same manner as in Example 1, it was confirmed that this product also has a certain degree of uniform color tone and operates as a solar cell without any problem.

Composition of resin coating film OH group-containing fluororesin [Made by Asahi Glass: Lumiflon LF200F, hydroxyl value 26 (mgKOH / g)] 20 parts by weight γ-butyrolactone 40 parts by weight Isophorone 30 parts by weight Defoamer (Toshiba Silicone: TSA -720) 3 parts by weight Leveling agent (manufactured by Shin-Etsu Silicone: KS-66) 1 part by weight First, in the above raw materials, Lumiflon resin was completely dissolved in a mixed solvent of γ-butyrolactone / isophorone, and the resulting mixture was zirconia ball mill for 48 hours. Dispersed. Then defoamer,
A leveling agent was added and the mixture was further mixed for 2 hours, and the following thermal crosslinking reaction components were added.

Methylated melamine resin (Sumitomo Chemical: Sumimal M-40ST) 4 parts by weight Catalyst (dodecylbenzene sulfonic acid) 0.13 parts by weight These are mixed and dispersed for 20 minutes to have transparency and insulation. A resin coating composition effective for protective sealing of the cell light-receiving surface was obtained.

The obtained composition was applied to the surface of the solar battery cell by a screen printing method and cured by heating at 150 ° C. for 90 minutes to give a resin coating film having a thickness of about 20 μm.

[0118]

As described above, according to the present invention, there is provided a solar cell module having a highly efficient power generation capability, maintaining a harmony in design, having no discomfort, and having a degree of freedom in design design. can do.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing one manufacturing process of a solar battery cell used in a solar battery module of the present invention.

FIG. 2 is a partial cross-sectional view showing one manufacturing process of a solar battery cell used in the solar battery module of the present invention.

FIG. 3 is a partial cross-sectional view showing one manufacturing process of a solar battery cell used in the solar battery module of the present invention.

FIG. 4 is a partial cross-sectional view showing a solar battery cell used in the solar battery module of the present invention.

FIG. 5 is a plan view showing a configuration example of a circular solar cell.

FIG. 6 is a partial cross-sectional view showing another configuration of the solar cell of the present invention.

[Explanation of symbols]

1 substrate 2 Lower electrode layer 3 Silicon-containing layer 4 insulating layers 5 Transparent electrode layer 6 element isolation layer 7 Element isolation layer 8 wiring electrodes 9 Lower electrode 10 through holes 10a opening 11 Insulating colored film 21 solar cells 22 Photoelectric converter 23 Element isolation part 25,26 Extraction electrode part 27, 28, 29 Connection

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 31/04-31/078

Claims (20)

(57) [Claims] 1. A light-receiving surface of a solar cell module having a photoelectric conversion unit for converting incident light into electricity, wherein the photoelectric conversion unit has silicon, and insulating coloring is applied to a portion other than the photoelectric conversion unit. It has a film, and this insulating colored film reduces the color difference with the photoelectric conversion part,
A solar cell module whose color difference ΔE is 3.0 or less and whose surface is made uniform by the color of the surface color of the photoelectric conversion section. 2. A light-receiving surface of a solar cell module having a photoelectric conversion part for converting incident light into electricity, wherein the photoelectric conversion part has silicon, and a portion other than the photoelectric conversion part is colored in an insulating manner. It has a film, and this insulating colored film reduces the color difference with the photoelectric conversion part,
The color difference ΔE is 3.0 or less, and a diffusion transmission layer having a white or light color tone is provided on the light receiving surface of the solar cell module, and insulation recognized through the diffusion transmission layer. Cell module in which the color difference ΔE between the colored film and the photoelectric conversion part is 3.0 or less. 3. The diffuse transmission layer has a total light transmittance of visible light of 20% or more and a haze of 50% or more.
Solar cell module. 4. A light-receiving surface of a solar cell module having a photoelectric conversion unit for converting incident light into electricity, wherein the photoelectric conversion unit has silicon, and insulating coloring is applied to a portion other than the photoelectric conversion unit. A film, the insulating colored film is reducing the color difference with the photoelectric conversion unit, the upper layer of the light receiving surface of the solar cell module has a black or near black diffuse transmission layer, A solar cell module in which the color difference ΔE between the insulating colored film and the photoelectric conversion part, which is recognized through the diffusion-transmissive layer, is 5.0 or less. 5. The solar cell module according to claim 4, wherein the diffuse transmission layer has a total light transmittance of visible light of 20 to 40% and a haze of 10 to 15%. 6. The solar cell module according to claim 1, wherein the insulating colored film has pigment particles dispersed in a binder. 7. The solar cell module according to claim 1, wherein the pigment particles dispersed in the insulating colored film are white fine particle pigments. 8. The solar cell module according to claim 1, wherein the photoelectric conversion section is a non-single crystal silicon film. 9. The solar cell module according to claim 2, further comprising a selective reflection layer as an upper layer and / or a lower layer of the diffuse transmission layer. 10. The solar cell module according to claim 1, wherein the photoelectric conversion section has a transparent conductive film. 11. The solar cell module according to any one of claims 1 to 10, which has a base material of any one of a resin having transparency and heat resistance, glass, and stainless steel. 12. A hot-melt material having a buffer adhesive layer containing a thermosetting resin is laminated on at least one surface of a substrate having translucency and heat resistance, glass, or stainless steel. Claims 1 to 1
1. The solar cell module according to any one of 1. 13. The solar cell module according to claim 12, wherein the base material and / or the buffer adhesive layer contains an ultraviolet absorber or is localized on the surface. 14. The solar cell module according to claim 12, wherein the buffer adhesive layer contains an organic peroxide. 15. The base film of a hot melt material according to claim 12, wherein the glass transition point of the base material before thermocompression bonding is 65 ° C. or higher, or the heat resistant temperature is 80 ° C. or higher. Battery module. 16. The substrate film of the hot melt material has a molecular orientation degree (MOR) value of 1.0 before thermocompression bonding.
It is -3.0, The solar cell module in any one of Claims 12-15. 17. The decomposition temperature of the organic peroxide having a half-life of 10 hours before thermocompression bonding is 70 ° C. or higher.
The solar cell module according to any one of to 16. 18. The solar cell module according to claim 1, further comprising a protective coating film having translucency and heat resistance on the photoelectric conversion section. 19. A solar cell module having the hot melt material layer according to claim 12 on the protective coating film. 20. A timepiece having the solar cell module according to claim 1.