Solar cell module

Abstract

To provide a solar cell module with improved design.SOLUTION: A solar cell module 1 includes a solar cell 2, and a printed matter 5 disposed on a light receiving surface 2a side of the solar cell 2. The printed matter 5 has a first color pattern layer comprising first color dots, a second color pattern layer comprising second color dots, and a third color pattern layer comprising third color dots. Dots of each color each include a binder and a pigment chip. Each pigment chip is any of a red interference pigment, a green interference pigment and a blue interference pigment which emit a color as interference light on a reflection light side. At least one interference pigment includes a small particle size grade interference pigment with a particle size range of 5-25 μm and a large particle size grade interference pigment with a particle size range of 25-40 μm, and the small particle size grade interference pigment is arranged in such a manner as to fill the gaps between the large particle size grade interference pigments.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a solar cell module. [Background technology]

[0002] With the aim of achieving carbon neutrality and a carbon-free society by 2050, there is a need for the widespread adoption of ZEBs (Net Zero Energy Buildings), which can significantly reduce energy consumption in buildings. A ZEB is a building that aims to achieve zero annual primary energy consumption while providing a comfortable indoor environment. Because people are active inside a building, it is impossible to achieve completely zero energy consumption. However, by reducing energy consumption through energy conservation and generating the equivalent energy through energy generation, it is possible to achieve net zero energy consumption.

[0003] Energy generation methods that do not use fossil fuels include, for example, solar power generation, wind power generation, and biomass power generation. As a method of energy generation in buildings, solar power generation is suitable when considering installation location and costs. The rooftop of a building is occupied by outdoor units for air conditioning and other equipment, so in order to generate electricity, solar cell modules must be installed on the walls other than the rooftop. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-027266 Summary of the Invention [Problem to be solved by the invention]

[0005] When a solar cell module is installed on a wall, conventional solar cell modules do not have sufficient design features, and improvements are desired.

[0006] An object of the present invention is to provide a solar cell module with improved design. [Means for solving the problem]

[0007] [1] One aspect of the present invention relates to a solar cell module including at least one solar cell and a printed material disposed on the light-receiving surface side of the solar cell. The printed material includes a first color pattern layer including a plurality of first color dots, a second color pattern layer disposed on the first color pattern layer and including a plurality of second color dots, and a third color pattern layer disposed on the second color pattern layer and including a plurality of third color dots. Each of the plurality of first color dots includes a first color binder and a plurality of first color pigment chips dispersed within the first color binder. Each of the plurality of second color dots includes a second color binder and a plurality of second color pigment chips dispersed within the second color binder. Each of the plurality of third color dots includes a third color binder and a plurality of third color pigment chips dispersed within the third color binder. The first color pigment chip, the second color pigment chip, and the third color pigment chip are each one of a red interference pigment, a green interference pigment, and a blue interference pigment that exhibits color as interference light on the reflected light side. At least one of the red interference pigment, the green interference pigment, and the blue interference pigment is composed of a small particle size grade interference pigment having a particle size range of 5 μm to 25 μm and a large particle size grade interference pigment having a particle size range of 25 μm to 40 μm. The small particle size grade interference pigment is arranged so as to fill the gaps between the large particle size grade interference pigments. The interference light is additively mixed.

[0008] The inventors' studies have revealed that when the particle size of the interference pigment used in the printed material (pattern printed layer) applied to a solar cell module is small, the color development required for a viewer to clearly recognize the color of the pattern is weakened, but the pattern does not appear too dark even when placed in front of a black surface such as a solar cell. On the other hand, when the particle size of the interference pigment used in the pattern printed layer is large, the transparency of the printed material increases, but the color development of the pattern can be improved. Therefore, the inventors have come up with a printed material that prevents the pattern from appearing too dark and has excellent color development by configuring at least one of red, green, and blue interference pigments to include a small particle size grade interference pigment and a large particle size grade interference pigment, and by arranging the small particle size grade interference pigment so as to fill the gaps between the large particle size grade interference pigments. Therefore, by applying a printed material having the above configuration to a solar cell module, a solar cell module can be provided that has a pattern with excellent visibility and color development and improved design. Furthermore, the inclusion of a large particle size grade interference pigment in this printed matter prevents a decrease in the transmittance of the picture printed layer. Therefore, a solar cell module using this printed matter effectively prevents a decrease in the light transmitted through the solar cell, and can maintain power generation efficiency.

[0009] [2] In another aspect, the present invention relates to a solar cell module including at least one solar cell and a printed material disposed on the light-receiving surface side of the solar cell. The printed material includes a first color pattern layer including a plurality of first color dots, a second color pattern layer disposed on the first color pattern layer and including a plurality of second color dots, and a third color pattern layer disposed on the second color pattern layer and including a plurality of third color dots. Each of the first color dots includes a first color binder and a plurality of first color pigment chips dispersed within the first color binder. Each of the second color dots includes a second color binder and a plurality of second color pigment chips dispersed within the second color binder. Each of the third color dots includes a third color binder and a plurality of third color pigment chips dispersed within the third color binder. The first color pigment chip, the second color pigment chip, and the third color pigment chip are each one of a red interference pigment, a green interference pigment, and a blue interference pigment that exhibits color as interference light on the reflected light side. At least one of the red, green, and blue interference pigments comprises a small particle size grade interference pigment having a particle size range of 5 μm to 25 μm and a large particle size grade interference pigment having a particle size range of 25 μm to 60 μm. The small particle size grade interference pigment is arranged to fill the gaps between the large particle size grade interference pigments. The interference light is additively mixed. In this case, the color development of the pattern can be improved. Furthermore, since the printed matter contains a large particle size grade interference pigment, a decrease in the transmittance of the pattern printed layer is suppressed. Therefore, a solar cell module using this printed matter effectively suppresses a decrease in light transmitted through the solar cell, thereby improving power generation efficiency.

[0010] [3] In the printed matter of [1] or [2] above, at least one of the small particle size grade interference pigment and the large particle size grade interference pigment may be an interference pigment containing titanium dioxide-coated mica. In this case, the wavelength of the interference light can be adjusted by adjusting the film thickness and transmittance of the titanium dioxide film. Furthermore, the perceived brightness can be improved by increasing the smoothness of the mica surface. As a result, a solar cell module with improved design can be provided.

[0011] [4] The solar cell module of any one of [1] to [3] above may further include a light-transmitting substrate provided on one side of the printed matter. In this case, the printed matter and the picture print layer can be protected without reducing the light transmitted to the solar cell.

[0012] [5] In any of the solar cell modules [1] to [4] above, the total light transmittance may be in the range of 30% to 90%. A total light transmittance of 30% or more can maintain power generation efficiency. On the other hand, a total light transmittance of 90% or less can prevent the pattern of the pattern-printed layer from appearing too dark.

[0013] [6] In any of the solar cell modules [1] to [5] above, the red, green, and blue interference pigments are each composed of a small particle size grade interference pigment having a particle size range of 5 μm to 25 μm and a large particle size grade interference pigment having a particle size range of 25 μm to 40 μm or 25 μm to 60 μm. In this case, a solar cell module can be provided that has a pattern with excellent visibility and color development in all colors, significantly improving design. Furthermore, a solar cell module using this printed material effectively suppresses the reduction in light transmitted through the solar cell, thereby improving power generation efficiency. [Effects of the Invention]

[0014] According to the present invention, a solar cell module with improved design is provided. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a cross-sectional view schematically showing a solar cell module according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a printed matter provided on the solar cell module shown in FIG. [Figure 3] FIG. 3 is a plan view schematically showing color dots provided on the printed matter shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view schematically showing a solar cell module according to the second embodiment. [Figure 5] 5(a) to 5(c) are cross-sectional views schematically showing a solar cell module according to a third embodiment. [Figure 6] 6(a) and 6(b) are cross-sectional views schematically showing a solar cell module according to a fourth embodiment. [Figure 7] 7(a) and 7(b) are cross-sectional views schematically showing a solar cell module according to a fifth embodiment. [Figure 8] FIG. 8 is a diagram schematically showing a white pattern layer provided on the solar cell module. [Figure 9] FIG. 9 is a table showing the configuration of printed matter according to Experimental Examples 1 to 3. DETAILED DESCRIPTION OF THE INVENTION

[0016] Specific examples of solar cell modules according to embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the following description, identical elements in the drawings will be designated by the same reference numerals, and duplicated descriptions will be omitted.

[0017] [First embodiment] Fig. 1 is a cross-sectional view schematically showing a solar cell module according to a first embodiment. As shown in Fig. 1, the solar cell module 1 includes thin solar cells 2, an encapsulant layer 3 that encapsulates the solar cells 2, an adhesive layer 4, a printed material 5, and a light-transmitting substrate 6. The solar cell module 1 may further include a backing material (not shown) below the encapsulant layer 3. The backing material is a member made of polyethylene terephthalate (PET), polycarbonate resin, acrylic resin, glass, or metal (such as aluminum) formed into a layer, film, or plate shape. The encapsulant layer 3 may be formed on such a backing material.

[0018] The solar cell 2 is a photoelectric conversion element formed in a thin plate shape with a thickness of about 0.2 mm and made of crystalline or amorphous silicon, thin-film silicon, perovskite, chalcopyrite, III-V, CdTe, CIS, or the like, that generates electricity by absorbing light with wavelengths mainly in the visible light range. The solar cell 2 is embedded (sealed) in the encapsulant layer 3 so that the light-receiving surface 2a faces the printed matter 5. The light-receiving surface 2a of the solar cell 2 is black or dark blue. Although the example shown in FIG. 1 shows three solar cell cells 2, the solar cell module 1 may include a large number of solar cell cells 2.

[0019] The encapsulant layer 3 is a layer formed from a transparent encapsulant material such as ethylene vinyl acetate (EVA), polyvinyl butyral (PVB), polyolefin resin, ionomer resin, silicone resin, etc. The encapsulant layer 3 is formed by surrounding and encapsulating the solar cell 2 with the transparent encapsulant material. The thickness of the encapsulant layer 3 is, for example, about 1 mm.

[0020] A transparent surface plate for protecting the solar cell 2 and the like may be provided on the encapsulant layer 3. Such a surface plate may be made of a transparent material such as polycarbonate resin, acrylic resin, or glass, and has a thickness of, for example, about 3 mm.

[0021] The printed matter 5 is a member for imparting design to the solar cell module 1. The printed matter 5 is attached to the front surface side of the encapsulant layer 3 by a transparent adhesive layer 4 or the like. Details of the printed matter 5 will be described later.

[0022] The light-transmitting substrate 6 is a substrate that is transparent to visible light. The light-transmitting substrate 6 is made of, for example, a transparent resin. Examples of transparent resins include PET, PMMA, polyethylene, polypropylene, nylon, PEN, and polycarbonate. The thickness of the light-transmitting substrate 6 is, for example, 25 μm to 250 μm. In the case of a glass substrate, the thickness of the light-transmitting substrate 6 is, for example, several mm to 10 mm. If necessary, a surface protection layer may be provided on the surface side of the light-transmitting substrate 6 (the side opposite to the printed matter 5).

[0023] The printed matter 5 is a layer that represents a pattern of the solar cell module 1. As shown in FIGS. 2 and 3 , the printed matter 5 includes a first color pattern layer 10 provided on one surface 6 a of the light-transmitting substrate 6, a second color pattern layer 20 provided on the first color pattern layer 10, and a third color pattern layer 30 provided on the second color pattern layer 20. The first color pattern layer 10, the second color pattern layer 20, and the third color pattern layer 30 are shown as layers in FIG. 2 for the sake of schematic illustration, but as shown in FIG. 3 , they are actually formed by a large number of dots. Specifically, the first color pattern layer 10 is formed by printing a plurality of first color dots 11, the second color pattern layer 20 is formed by printing a plurality of second color dots 21, and the third color pattern layer 30 is formed by printing a plurality of third color dots 31. The second color dots 21 may be printed directly on the surface 6a of the light-transmitting substrate 6 in areas where the first color dots 11 are not printed, and the third color dots 31 may be printed directly on the surface 6a of the light-transmitting substrate 6 in areas where the first color dots 11 or the second color dots 21 are not printed.

[0024] The first color pattern layer 10 can be formed on the surface 6a of the light-transmitting substrate 6 by, for example, screen printing, inkjet printing, gravure printing, or offset printing (hereinafter also referred to as "screen printing, etc."). As shown in FIGS. 2 and 3, the first color pattern layer 10 is composed of a plurality of first color dots 11. Here, "dot" refers to a point that is an element constituting a printed image, and its shape is not limited to a circle but may be a rectangle, a polygon, or other shape. The same applies to the shapes of the dots in the second color pattern layer 20 and the third color pattern layer 30. Each of the plurality of first color dots 11 contains a first color binder 12 and a plurality of first color pigment chips 13 dispersed within the first color binder 12. The content of the plurality of first color pigment chips 13 is, for example, in the range of 0.5 parts by weight to 20 parts by weight, where the first color binder 12 is 100 parts by weight.

[0025] Examples of the first color binder 12 include vinyl chloride-vinyl acetate copolymer resin, acrylic resin, thermoplastic urethane resin, polyester resin, and ethylene vinyl acetate (EVA) resin. The thickness of the first color pattern layer 10 is, for example, 1 μm to 10 μm. The first color pattern layer 10 may contain a curing agent. The binders in the second color pattern layer 20 and the third color pattern layer 30 may also be formed from the same material and have the same thickness.

[0026] Each of the multiple first color pigment chips 13 is a first interference pigment 14 that generates interference light. Each first interference pigment 14 is composed of a thin flake (not shown) that is transparent to visible light and a metal oxide film (not shown) that covers the flake. Light L incident on the first color pattern layer 10 from the translucent substrate 6 side is reflected by the surface of the metal oxide film, and light that passes through the metal oxide film and is reflected by the surface of the flake interferes with each other, generating first interference light L1. Adjusting the thickness and refractive index of the metal oxide film allows the generation of interference light with a desired wavelength.

[0027] Each of the first interference pigments 14 is, for example, titanium dioxide-coated mica. The flakes that make up the first interference pigments 14 may be made of a material other than mica, such as silica, alumina, glass, or polysilicate. The metal oxide film that makes up the first interference pigments 14 may be made of a material other than titanium dioxide, such as zirconium oxide, zinc oxide, iron oxide, or tin oxide.

[0028] The first interference pigment 14 includes a plurality of small particle size grade titanium dioxide-coated micas 15 having a particle size range of 5 μm to 25 μm and a plurality of large particle size grade titanium dioxide-coated micas 16 having a particle size range of 25 μm to 40 μm. The average particle size (D50) of the titanium dioxide-coated micas 15 is, for example, approximately 15 μm, and the average particle size (D50) of the titanium dioxide-coated micas 16 is, for example, approximately 25 μm. That is, the average particle size of the titanium dioxide-coated micas 15 is smaller than the average particle size of the titanium dioxide-coated micas 16. The particle size range of the titanium dioxide-coated micas 16 may be 25 μm to 60 μm. In this case, the average particle size (D50) of the titanium dioxide-coated micas 16 is, for example, approximately 35 μm. As shown in FIG. 2, each of the plurality of titanium dioxide-coated micas 15 is arranged so as to fill the gaps between the plurality of titanium dioxide-coated micas 16. Here, the term "particle size" means the longest diameter of the particle cross section.

[0029] When incident light L enters the first color pattern layer 10, a first interference light L1 is generated from each of the titanium dioxide-coated micas 15, 16 of the first interference pigment 14. The first interference pigment 14 is, for example, any one of a red interference pigment (red pearl pigment), a green interference pigment (green pearl pigment), and a blue interference pigment (blue pearl pigment), and one example is a red interference pigment (red pearl pigment). The blending amounts of the titanium dioxide-coated micas 15, 16 of the first interference pigment may be the same or different from each other.

[0030] The second color pattern layer 20 can be provided on the first color pattern layer 10 by, for example, screen printing or the like. As shown in FIGS. 2 and 3, the second color pattern layer 20 is composed of a plurality of second color dots 21. Each of the plurality of second color dots 21 includes a second color binder 22 and a plurality of second color pigment chips 23 dispersed within the second color binder 22. The content of the plurality of second color pigment chips 23 is, for example, in the range of 0.5 parts by weight to 20 parts by weight, where the second color binder 22 is 100 parts by weight.

[0031] The multiple second color pigment chips 23 are second interference pigments 24 that generate interference light. Each second interference pigment 24 is composed of a thin flake (not shown) that is transparent to visible light and a metal oxide film (not shown) that covers the thin flake. Light L incident on the second color pattern layer 20 from the translucent substrate 6 side that is reflected on the surface of the metal oxide film interferes with light that passes through the metal oxide film and is reflected on the surface of the flake, generating second interference light L2. Interference light having a desired wavelength can be generated by adjusting the film thickness and refractive index of the metal oxide film.

[0032] Each of the second interference pigments 24 is, for example, titanium dioxide-coated mica. The flakes that make up the second interference pigments 24 may be made of a material other than mica, such as silica, alumina, glass, or polysilicate. The metal oxide film that makes up the second interference pigments 24 may be made of a material other than titanium dioxide, such as zirconium oxide, zinc oxide, iron oxide, or tin oxide.

[0033] Similar to the first interference pigment 14, the second interference pigment 24 includes a plurality of small particle size grade titanium dioxide-coated micas 25 having a particle size range of 5 μm to 25 μm and a plurality of large particle size grade titanium dioxide-coated micas 26 having a particle size range of 25 μm to 40 μm. The average particle size (D50) of the titanium dioxide-coated micas 25 is, for example, approximately 15 μm, and the average particle size (D50) of the titanium dioxide-coated micas 26 is, for example, approximately 25 μm. That is, the average particle size of the titanium dioxide-coated micas 25 is smaller than the average particle size of the titanium dioxide-coated micas 26. The particle size range of the titanium dioxide-coated micas 26 may be 25 μm to 60 μm. In this case, the average particle size (D50) of the titanium dioxide-coated micas 26 is, for example, approximately 35 μm. As shown in FIG. 2 , each of the plurality of titanium dioxide-coated micas 25 is arranged so as to fill the gaps between the plurality of titanium dioxide-coated micas 26.

[0034] When incident light L enters the second color pattern layer 20, second interference light L2 is generated from each of the titanium dioxide-coated micas 25, 26 of the second interference pigment 24. The second interference pigment 24 is, for example, any one of a red interference pigment (red pearl pigment), a green interference pigment (green pearl pigment), and a blue interference pigment (blue pearl pigment), and one example is a green interference pigment (green pearl pigment). The blending amounts of the titanium dioxide-coated micas 25, 26 of the second interference pigment 24 may be the same or different from each other.

[0035] The third color pattern layer 30 can be provided on the second color pattern layer 20 by, for example, screen printing or the like. As shown in FIGS. 2 and 3, the third color pattern layer 30 is composed of a plurality of third color dots 31. Each of the plurality of third color dots 31 includes a third color binder 32 and a plurality of third color pigment chips 33 dispersed within the third color binder 32. The content of the plurality of third color pigment chips 33 is, for example, in the range of 0.5 parts by weight to 20 parts by weight, where the third color binder 32 is taken as 100 parts by weight.

[0036] The multiple third color pigment chips 33 are third interference pigments 34 that generate interference light. Each third interference pigment 34 is composed of a thin flake (not shown) that is transparent to visible light and a metal oxide film (not shown) that covers the flake. Light L incident on the third color pattern layer 30 from the translucent substrate 6 side is reflected by the surface of the metal oxide film, and light that passes through the metal oxide film and is reflected by the surface of the flake interferes with each other, generating third interference light L3. Adjusting the thickness and refractive index of the metal oxide film allows the generation of interference light with a desired wavelength.

[0037] Each of the third interference pigments 34 is, for example, titanium dioxide-coated mica. The flakes that make up the third interference pigments 34 may be made of a material other than mica, such as silica, alumina, glass, or polysilicate. The metal oxide film that makes up the third interference pigments 34 may be made of a material other than titanium dioxide, such as zirconium oxide, zinc oxide, iron oxide, or tin oxide.

[0038] Like the first interference pigment 14 and the second interference pigment 24, the third interference pigment 34 includes a plurality of small particle size grade titanium dioxide-coated micas 35 having a particle size range of 5 μm to 25 μm and a plurality of large particle size grade titanium dioxide-coated micas 36 having a particle size range of 25 μm to 40 μm. The average particle size (D50) of the titanium dioxide-coated micas 35 is, for example, approximately 15 μm, and the average particle size (D50) of the titanium dioxide-coated micas 36 is, for example, approximately 25 μm. That is, the average particle size of the titanium dioxide-coated micas 35 is smaller than the average particle size of the titanium dioxide-coated micas 36. The particle size range of the titanium dioxide-coated micas 36 may be 25 μm to 60 μm. In this case, the average particle size (D50) of the titanium dioxide-coated micas 36 is, for example, approximately 35 μm. 2, the plurality of titanium dioxide-coated mica particles 35 are arranged so as to fill the gaps between the plurality of titanium dioxide-coated mica particles 36. Here, the "particle size" means the longest diameter of the cross section of the particle.

[0039] When incident light L enters the third color pattern layer 30, the titanium dioxide-coated mica 35, 36 of the third interference pigment 34 generates third interference light L3. The third interference pigment 34 is, for example, any one of a red interference pigment (red pearl pigment), a green interference pigment (green pearl pigment), and a blue interference pigment (blue pearl pigment), and one example is a blue interference pigment (blue pearl pigment). The titanium dioxide-coated mica 35, 36 of the third interference pigment 34 may be blended in the same amount or in different amounts. Note that the first interference pigment 14 is any one of red, green, and blue interference pigments; the second interference pigment 24 is any one of red, green, and blue that is different from the first interference pigment 14; and the third interference pigment 34 is any one of red, green, and blue that is different from the first interference pigment 14 and the second interference pigment 24. This allows the printed matter 5, which is a picture-printed layer, to function as an RGB interference pigment printed layer.

[0040] In the printed matter 5, the pattern in the pattern printing layer of the printed matter 5 is expressed by additively mixing the first interference light L1 generated by the first interference pigment 14, the second interference light L2 generated by the second interference pigment 24, and the third interference light L3 generated by the third interference pigment 34.

[0041] The total light transmittance of the printed matter 5 (and the solar cell module 1) is, for example, 30% to 90%. The total light transmittance here refers to a value measured using a spectrophotometer (for example, the UV-2100 spectrophotometer manufactured by Shimadzu Corporation). The light here refers to light in the wavelength range of 380 nm to 780 nm.

[0042] As described above, in the solar cell module 1 according to this embodiment, the red, green, and blue interference pigments are configured to include both small-particle-grade and large-particle-grade interference pigments, with the small-particle-grade interference pigments arranged to fill the gaps between the large-particle-grade interference pigments. This prevents the pattern from appearing too dark, improving visibility. The solar cell module 1 thus provides a design with excellent color development and improved aesthetics. Furthermore, the printed matter 5 contains a large-particle-grade interference pigment, which reduces the loss of transparency of the pattern-printed layer. Therefore, the solar cell module 1 using the printed matter 5 effectively reduces the loss of light transmitted through the solar cell 2, maintaining power generation efficiency.

[0043] In the solar cell module 1 according to this embodiment, the large particle size grade interference pigment may have a particle size range of 25 μm to 60 μm. In this case, the color development of the pattern can be improved. Furthermore, since the printed matter 5 contains a large particle size grade interference pigment, a decrease in the transparency of the pattern printed layer is suppressed. Therefore, with a solar cell module 1 using this printed matter, a decrease in the transmitted light to the solar cell 2 is effectively suppressed, and power generation efficiency can be improved.

[0044] In the solar cell module 1 according to this embodiment, at least one of the small particle size grade interference pigment and the large particle size grade interference pigment may be an interference pigment containing titanium dioxide-coated mica. In this case, the wavelength of the interference light can be adjusted by adjusting the film thickness and transmittance of the titanium dioxide film. Furthermore, the perceived brightness can be improved by increasing the smoothness of the mica surface. As a result, a solar cell module 1 with improved design can be provided.

[0045] The solar cell module 1 according to this embodiment further includes a light-transmitting base material 6 provided on one side of the printed matter 5. This makes it possible to protect the printed matter 5 and each picture printed layer without reducing the light transmitted to the solar cell 2.

[0046] The solar cell module 1 according to this embodiment may have a total light transmittance in the range of 30% to 90%. A total light transmittance of 30% or more can maintain power generation efficiency. On the other hand, a total light transmittance of 90% or less can prevent the pattern of the pattern printing layer from appearing too dark.

[0047] In the solar cell module 1 according to this embodiment, the red interference pigment, green interference pigment, and blue interference pigment are all composed of a small particle size grade interference pigment having a particle size range of 5 μm to 25 μm and a large particle size grade interference pigment having a particle size range of 25 μm to 40 μm (or 25 μm to 60 μm). In this case, it is possible to provide a solar cell module 1 having a design with excellent visibility and color development in all colors, thereby improving design. Furthermore, a solar cell module 1 using this printed material effectively suppresses the reduction in light transmitted through the solar cell 2, thereby improving power generation efficiency.

[0048] [Second embodiment] Next, a solar cell module according to a second embodiment will be described with reference to Fig. 4. As shown in Fig. 4, a solar cell module 1A according to the second embodiment includes thin plate-shaped solar cells 2, a sealant layer 3 that seals the solar cells 2, an adhesive layer 4, a printed matter 5, a translucent base material 6, and a top coat layer 7. The solar cells 2, the sealant layer 3, the adhesive layer 4, the printed matter 5, and the translucent base material 6 have the same configurations as those in the first embodiment.

[0049] The top coat layer 7 is a coating layer for protecting the printed matter 5 and the translucent substrate 6, protecting the surface of the solar cell module 1A. The top coat layer 7 is a transparent sheet-like layer formed by coating with a hard resin and can impart weather resistance, contamination resistance, and scratch resistance to the solar cell module 1A. For example, an acrylic urethane resin obtained by adding an isocyanate to an acrylic polyol and curing the resin can be used as the main resin. The top coat layer 7 can be prepared by adding an ultraviolet absorber and a hindered amine light stabilizer to an acrylic polyol as the main resin and hexamethylene diisocyanate as the curing agent. A benzotriazole ultraviolet absorber is typically used as the ultraviolet absorber. The top coat layer 7 is not limited to the above-mentioned materials and may be formed from various active energy ray-curable coating compositions or thermosetting coating compositions that are cured by ultraviolet irradiation or electron beams.

[0050] The thickness of the top coat layer 7 may be, for example, 5 to 50 μm, preferably 10 to 40 μm, and more preferably 15 to 30 μm.

[0051] According to this solar cell module 1A, in addition to the same effects as those of the first embodiment, the top coat layer 7 can reliably protect the printed matter 5 and the like.

[0052] [Third embodiment] Next, a solar cell module according to a third embodiment will be described with reference to Fig. 5. As shown in Fig. 5(a), a solar cell module 1B according to the third embodiment includes thin solar cells 2, a sealant layer 3 that seals the solar cells 2, a printed matter 5, a translucent base material 6, and a second sealant layer 8. The solar cells 2, the sealant layer 3, the printed matter 5, and the translucent base material 6 have the same configurations as those in the first embodiment. The second sealant layer 8 is disposed, for example, between the sealant layer 3 and the printed matter 5. In this solar cell module 1B, the second sealant layer 8 is provided instead of the adhesive layer 4. The material for forming the second sealant layer 8 can be the same as the material for forming the sealant layer 3.

[0053] In this solar cell module 1B, glass is used as the light-transmitting base material 6, and the printed matter 5 can be formed by printing on this glass-made light-transmitting base material 6. This printed matter 5 is then sealed with a second sealing material layer 8. This is attached to the sealing material layer 3 that seals the solar cells 2, thereby producing the solar cell module 1B. When the light-transmitting base material 6 is made of glass, it becomes easy to use the light-transmitting base material 6 as the outermost layer.

[0054] In the third embodiment, as in a modified solar cell module 1C shown in Fig. 5(b), the printed matter 5 may be printed on the second encapsulant layer 8. In this case, the layer configuration is the same as that of the solar cell module 1B. Alternatively, as in a modified solar cell module 1D shown in Fig. 5(c), the printed matter 5 may be printed on the second encapsulant layer 8, and the printed matter 5 may face the encapsulant layer 3 that encapsulates the solar cells 2.

[0055] In addition to the same advantageous effects as those of the first embodiment, these solar cell modules 1B, 1C, and 1D can reduce the thickness of the solar cell module by printing the printed matter 5. Also, displacement of the printed matter 5 can be prevented.

[0056] [Fourth embodiment] Next, a solar cell module according to a fourth embodiment will be described with reference to Fig. 6. As shown in Fig. 6(a), a solar cell module 1E according to the fourth embodiment includes thin-plate solar cells 2, a sealant layer 3 that seals the solar cells 2, a printed matter 5, light-transmitting base materials 6A and 6B, and second sealant layers 8A and 8B. The solar cells 2, the sealant layer 3, and the printed matter 5 have the same configurations as those in the first embodiment. The light-transmitting base materials 6A and 6B correspond to the light-transmitting base material 6 in the first embodiment, and the second sealant layers 8A and 8B correspond to the second sealant layer 8 in the third embodiment. In the solar cell module 1E, the light-transmitting base materials and the second sealant layers are formed to form pairs, respectively.

[0057] In this solar cell module 1E, the outermost light-transmitting base material 6B is made of glass, and the inner light-transmitting base material 6A is made of a resin film. The printed matter 5 is printed, for example, on the inner light-transmitting base material 6A. The light-transmitting base material 6A on which the printed matter 5 is printed is then sandwiched and sealed between a pair of second sealing material layers 8A, 8B. This forms the solar cell module 1E shown in FIG. 6(a). Note that in the solar cell module 1F shown in FIG. 6(b), the vertical direction of the printed matter 5 printed on the light-transmitting base material 6A made of a resin film is changed so that the printed matter 5 comes into contact with the second sealing material layer 8B.

[0058] In addition to the same advantageous effects as any of the above-described embodiments, these solar cell modules 1E and 1F can use a resin film on which the printed matter 5 is pre-printed, thereby improving manufacturing efficiency.

[0059] [Fifth embodiment] Next, a solar cell module according to a fifth embodiment will be described with reference to FIG. 7. As shown in FIG. 7(a), a solar cell module 1G according to the fifth embodiment includes thin solar cells 2, a sealant layer 3 that seals the solar cells 2, a printed matter 5, light-transmitting base materials 6A and 6B, and second sealant layers 8A and 8B. The solar cell module 1G has a layer structure substantially similar to that of the solar cell module 1E according to the fourth embodiment (see FIG. 6(a)). However, in the solar cell module 1G, both the light-transmitting base materials 6A and 6B are formed from a resin film. Note that a solar cell module 1H shown in FIG. 7(b) also has a layer structure substantially similar to that of the solar cell module 1F according to the fourth embodiment (see FIG. 6(b)), but differs in that both the light-transmitting base materials 6A and 6B are formed from a resin film.

[0060] These solar cell modules 1G and 1H can reduce the weight of the entire solar cell module in addition to providing the same effects as those of the fourth embodiment. To further enhance the durability of these solar cell modules, a highly weather-resistant substrate such as a fluorine-based film or an acrylic film may be used for the outermost translucent substrate 6B.

[0061] Although the solar cell modules 1, 1A to 1H according to the present invention have been described above, the solar cell modules according to the present invention are not limited to the above-described embodiments, and various other modifications are possible.

[0062] For example, in the solar cell modules 1, 1A to 1H, a transparent smoke-printed layer may be further provided between the encapsulant layer 3 that encapsulates the solar cells 2 and the printed matter 5. The transparent smoke-printed layer attenuates light transmitted through the printed matter 5 to an extent that does not affect solar power generation. The transparent smoke-printed layer can be provided on the printed matter 5 (e.g., the third color pattern layer 30) by, for example, screen printing, inkjet printing, gravure printing, or offset printing using an ink in which a small amount of carbon black is dispersed in a resin binder such as a vinyl, acrylic, urethane, or polyester binder. The thickness of the transparent smoke-printed layer is, for example, 1 μm to 10 μm. The transparent smoke-printed layer enhances the color development of the printed matter 5 and further improves the design. Furthermore, because the transparent smoke-printed layer is transparent, a decrease in light transmitted through the solar cells 2 is effectively suppressed.

[0063] Furthermore, in the solar cell modules 1, 1A to 1H, a white pattern layer 9 shown in FIG. 8 may be further provided between the encapsulant layer 3 that encapsulates the solar cells 2 and the printed matter 5. The white pattern layer 9 can be provided on the printed matter 5 by, for example, screen printing, inkjet printing, gravure printing, or offset printing. The white pattern layer 9 can be composed of a plurality of silver dots 9a. Each of the plurality of silver dots 9a contains a silver binder 9b and a plurality of silver pigment chips 9c dispersed within the silver binder 9b. The content of the plurality of silver pigment chips 9c is, for example, in the range of 0.5 parts by weight to 20 parts by weight, where the silver binder is 100 parts by weight.

[0064] Examples of the binder 9b for silver include vinyl resins, acrylic resins, thermoplastic urethane resins, polyester resins, polycarbonate resins, and ethylene vinyl acetate (EVA) resins. The thickness of the white pattern layer 9 is, for example, 1 μm to 10 μm. The white pattern layer 9 may contain a curing agent. In this case, the heat resistance of the white pattern layer 9 and the adhesion of the white pattern layer 9 to the printed matter 5 can be improved. This provides excellent color development of the printed matter 5 and allows the printed matter 5 to have a pattern that gives a whitish impression.

[0065] [Experimental Example] Here, the tendency of the appearance of the pattern depending on the particle size of the titanium dioxide-coated mica contained in the pattern-printed layer will be explained using experimental examples. As shown in Figure 9 and Experimental Examples 1 to 3 described below, printed matter was produced by adjusting the particle size of the titanium dioxide-coated mica. Figure 9 is a diagram showing the configuration of the printed matter according to Experimental Examples 1 to 3. A black surface member (a member corresponding to a solar cell) was placed on the back side (the side of the transparent smoke-printed layer placed on the opposite side from the translucent substrate) of the printed matter according to Experimental Examples 1 to 3. The distance between the printed matter (including the white pattern layer and the transparent smoke-printed layer) and the black surface member was set to 2 mm. In this state, the visibility of the pattern-printed layer (items 1 and 2 described below) was evaluated. Sensory evaluation was performed by four people for items 1 and 2, and the average score was calculated.

[0066] <Experimental Example 1> A printed material was produced by sequentially depositing a first color pattern layer, a second color pattern layer, a third color pattern layer, a white pattern layer, and a transparent smoke print layer on a transparent PET substrate. In Experimental Example 1, the first color pattern layer was formed by screen printing using an ink containing a first color binder (urethane resin) and a red interference pigment dispersed within the first color binder. The red interference pigment content was 8 parts by weight of a red interference pigment with a particle size of 10 to 40 μm and 2 parts by weight of a red interference pigment with a particle size of 5 to 25 μm, relative to 100 parts by weight of the first color binder.

[0067] In Experimental Example 1, a second color pattern layer was formed by screen printing using an ink containing a second color binder (urethane resin) and a green interference pigment dispersed within the second color binder. The green interference pigment content was 4 parts by weight of a green interference pigment with a particle size of 10 to 40 μm and 1 part by weight of a green interference pigment with a particle size of 5 to 25 μm, relative to 100 parts by weight of the second color binder.

[0068] In Experimental Example 1, a third color pattern layer was formed by screen printing using an ink containing a third color binder (urethane resin-based) and a blue interference pigment dispersed within the third color binder. The blue interference pigment content was 1 part by weight of a blue interference pigment having a particle size of 10 to 40 μm and 1 part by weight of a blue interference pigment having a particle size of 5 to 25 μm, relative to 100 parts by weight of the third color binder. The red interference pigment, green interference pigment, and blue interference pigment were all titanium dioxide-coated mica.

[0069] In Experimental Example 1, a white pattern layer was formed by screen printing using an ink containing a silver binder (urethane resin) and silver pigment chips dispersed within the silver binder. The silver pigment chip content was 1 part by weight of silver pigment chips with particle sizes of 5 to 25 μm per 100 parts by weight of the silver binder. Furthermore, a transparent smoke print layer was formed by screen printing using an ink containing a medium ink and a black ink in a ratio of 40:1.

[0070] <Experimental Example 2> A printed material was produced by sequentially depositing a first color pattern layer, a second color pattern layer, a third color pattern layer, a white pattern layer, and a transparent smoke print layer on a transparent PET substrate. In Experimental Example 2, the first color pattern layer was formed by screen printing using an ink containing a first color binder (urethane resin) and a red interference pigment dispersed within the first color binder. The red interference pigment content was 8 parts by weight of a red interference pigment with a particle size of 10 to 40 μm and 2 parts by weight of a red interference pigment with a particle size of 5 to 25 μm, relative to 100 parts by weight of the first color binder.

[0071] In Experimental Example 2, a second color pattern layer was formed by screen printing using an ink containing a second color binder (urethane resin) and a green interference pigment dispersed within the second color binder. The green interference pigment content was 4 parts by weight of a green interference pigment with a particle size of 10 to 40 μm and 1 part by weight of a green interference pigment with a particle size of 5 to 25 μm, relative to 100 parts by weight of the second color binder.

[0072] In Experimental Example 2, a third color pattern layer was formed by screen printing using an ink containing a third color binder (urethane resin-based) and a blue interference pigment dispersed within the third color binder. The content of the blue interference pigment was 1 part by weight, with a particle size of 10 to 40 μm, for every 100 parts by weight of the third color binder. The red interference pigment, green interference pigment, and blue interference pigment were all titanium dioxide-coated mica.

[0073] In Experimental Example 2, a white pattern layer was formed by screen printing using an ink containing a silver binder (urethane resin) and silver pigment chips dispersed within the silver binder. The silver pigment chip content was 1 part by weight of silver pigment chips with particle sizes of 5 to 25 μm per 100 parts by weight of the silver binder. Furthermore, a transparent smoke print layer was formed by screen printing using an ink containing a medium ink and a black ink in a ratio of 40:1.

[0074] <Experimental Example 3> A printed material was produced by sequentially depositing a first color pattern layer, a second color pattern layer, a third color pattern layer, and a transparent smoke print layer on a transparent PET substrate. In Experimental Example 3, the first color pattern layer was formed by screen printing using an ink containing a first color binder (urethane resin) and a red interference pigment dispersed within the first color binder. The red interference pigment content was 8 parts by weight of a red interference pigment with a particle size of 10 to 40 μm and 2 parts by weight of a red interference pigment with a particle size of 5 to 25 μm, relative to 100 parts by weight of the first color binder.

[0075] In Experimental Example 3, a second color pattern layer was formed by screen printing using an ink containing a second color binder (urethane resin) and a green interference pigment dispersed within the second color binder. The content of the green interference pigment was 4 parts by weight, with a particle size of 5 to 25 μm, for 100 parts by weight of the second color binder.

[0076] In Experimental Example 3, a third color pattern layer was formed by screen printing using an ink containing a third color binder (urethane resin-based) and a blue interference pigment dispersed within the third color binder. The content of the blue interference pigment was 1 part by weight, with a particle size of 5 to 25 μm, for every 100 parts by weight of the third color binder. The red interference pigment, green interference pigment, and blue interference pigment were all titanium dioxide-coated mica.

[0077] In Experimental Example 3, a transparent smoke print layer was formed by screen printing using a mixture of medium ink and black ink in a ratio of 40:1.

[0078] <Item 1: Regarding the effect of a black surface on the printed image layer placed behind the screen> The influence of a black surface member on the picture print layer was evaluated. <Score> 5 points: There is no influence of black and the image is fully visible. 3 points: The influence of the black color is slightly noticeable, and the image appears to be somewhat dark and sunken (slightly high transparency). 1 point: The influence of black is evident, and the image appears to be quite dark and sunken (high transparency).

[0079] <Item 2: Color development of the pattern> The color development of the pattern was evaluated when a member with a black surface was placed behind it. <Score> 5 points: The color of the pattern is good. 3 points: The color of the pattern is slightly weak and the color of the pattern appears pale (whitish). 1 point: The color of the pattern is weak and the color of the pattern appears white.

[0080] The results of the sensory evaluations of items 1 and 2 for Experimental Examples 1 to 3 are shown in Table 1 below. Evaluations of 3 points or higher were deemed to be acceptable for practical use. Experimental Example 1 revealed that the visibility of the pattern tended to be expressed at a sufficiently high level. High evaluation results were also obtained for the color development of the pattern. Experimental Example 2 revealed that the effect of the black surface on the pattern was minimized, while the color development of the pattern tended to be generally satisfactory. Experimental Example 3 revealed that the effect of the black surface on the pattern was minimized, resulting in satisfactory visibility of the pattern. The color development of the pattern also had a level of performance that was acceptable for practical use.

[0081] [Table 1] [Explanation of symbols]

[0082] 1, 1A to 1H... solar cell module, 2... solar cell cell, 2a... light-receiving surface, 3... encapsulant layer, 4... adhesive layer, 5... printed matter, 6, 6A, 6B... light-transmitting substrate, 7... top coat layer, 8, 8A, 8B... second encapsulant layer, 10... first color pattern layer, 11... first color dots, 12... first color binder, 13... first color pigment chips, 14... first interference pigment, 15, 25, 35... titanium dioxide-coated mica, 16, 26, 36... titanium dioxide-coated mica, 20... second color pattern layer, 21... second color dots, 22... second color binder, 23... second color pigment chips, 24... second interference pigment, 30... third color pattern layer, 31... third color dots, 32... third color binder, 33... third color pigment chips, 34... third interference pigment.

Claims

1. at least one solar cell; a printed matter disposed on the light-receiving surface side of the solar cell, The printed matter is a first color pattern layer formed of a plurality of first color dots; a second color pattern layer provided on the first color pattern layer and configured with a plurality of second color dots; a third color pattern layer provided on the second color pattern layer and configured by a plurality of third color dots; each of the plurality of first color dots includes a first color binder and a plurality of first color pigment chips dispersed within the first color binder; each of the plurality of second color dots includes a second color binder and a plurality of second color pigment chips dispersed within the second color binder; each of the plurality of third color dots includes a third color binder and a plurality of third color pigment chips dispersed within the third color binder; each of the first color pigment chip, the second color pigment chip, and the third color pigment chip is any one of a red interference pigment, a green interference pigment, and a blue interference pigment that develops a color as interference light on the reflected light side; at least one of the red interference pigment, the green interference pigment, and the blue interference pigment comprises a small particle size grade interference pigment having a particle size range of 5 μm to 25 μm and a large particle size grade interference pigment having a particle size range of 25 μm to 40 μm; The small particle size grade interference pigments are arranged to fill gaps between the large particle size grade interference pigments, and the interference light is additively mixed.

2. at least one solar cell; a printed matter disposed on the light-receiving surface side of the solar cell, The printed matter is a first color pattern layer formed of a plurality of first color dots; a second color pattern layer provided on the first color pattern layer and configured with a plurality of second color dots; a third color pattern layer provided on the second color pattern layer and configured by a plurality of third color dots; each of the plurality of first color dots includes a first color binder and a plurality of first color pigment chips dispersed within the first color binder; each of the plurality of second color dots includes a second color binder and a plurality of second color pigment chips dispersed within the second color binder; each of the plurality of third color dots includes a third color binder and a plurality of third color pigment chips dispersed within the third color binder; each of the first color pigment chip, the second color pigment chip, and the third color pigment chip is any one of a red interference pigment, a green interference pigment, and a blue interference pigment that develops a color as interference light on the reflected light side; at least one of the red interference pigment, the green interference pigment, and the blue interference pigment comprises a small particle size grade interference pigment having a particle size range of 5 μm to 25 μm, and a large particle size grade interference pigment having a particle size range of 25 μm to 60 μm; The small particle size grade interference pigments are arranged to fill gaps between the large particle size grade interference pigments, and the interference light is additively mixed.

3. At least one of the small particle size grade interference pigment and the large particle size grade interference pigment is an interference pigment containing titanium oxide-coated mica. The solar cell module according to claim 1 or 2.

4. Further provided with a light-transmitting substrate provided on one side of the printed matter, The solar cell module according to claim 1 or 2.

5. The total light transmittance is in the range of 30% to 90%. The solar cell module according to claim 1 or 2.

6. Each of the red interference pigment, the green interference pigment, and the blue interference pigment is configured to include a small particle size grade interference pigment having a particle size range of 5 μm to 25 μm, and a large particle size grade interference pigment having a particle size range of 25 μm to 40 μm or 25 μm to 60 μm. The solar cell module according to claim 1 or 2.

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