Wiring blackout sheet and solar cell module

Abstract

The present disclosure provides a wiring blackout sheet disposed inside a solar cell module.

Description

Wiring concealment sheets and solar modules

[0001] This disclosure relates to wiring concealment sheets and solar cell modules.

[0002] In recent years, with growing awareness of environmental issues, solar cells have attracted attention as a clean energy source. Generally, a solar cell module has a structure in which a surface protective member, a surface sealing material, a solar cell element, a back sealing material, and a back protective member are stacked in that order from the light-receiving side, and it has the function of generating electricity when sunlight is incident on the solar cell element.

[0003] Incidentally, in recent years, aesthetic appeal has become increasingly important for solar cell modules. There is a growing demand to install solar cell modules in a way that does not detract from the appearance or landscape of the installation site. In particular, the use of metal in the wiring, which has a metallic sheen, and the fact that the wiring and solar cell elements are different colors, means that the wiring stands out and detracts from the aesthetics.

[0004] To make the wiring less noticeable, for example, Patent Document 1 proposes a solar cell module in which multiple solar cells are arranged and connected by wiring material, in which the surface of the wiring material is covered with a colored resin layer.

[0005] Japanese Patent Publication No. 2001-339089

[0006] As described in Patent Document 1, covering the surface of the wiring material with a colored resin layer may cause poor bonding between the solar cell and the wiring material. In addition, in this case, the heat generated when bonding the solar cell and the wiring material may cause the resin layer to peel off, potentially impairing the appearance quality.

[0007] This disclosure is made in view of the above circumstances and primarily aims to provide a novel wiring concealment sheet.

[0008] One embodiment of the present disclosure provides a wiring concealment sheet that is placed inside a solar cell module.

[0009] Another embodiment of the present disclosure provides a solar cell module in which the aforementioned wiring concealment sheet is located inside the solar cell module.

[0010] This disclosure provides a novel wiring concealment sheet.

[0011] This is a schematic cross-sectional view illustrating a wiring concealment sheet in this disclosure. This is a schematic cross-sectional view illustrating a solar cell module in this disclosure. This is a schematic cross-sectional view illustrating a wiring concealment sheet in this disclosure. This is a schematic cross-sectional view illustrating a solar cell module in this disclosure. This is a schematic cross-sectional view illustrating a wiring concealment sheet in this disclosure. This is a schematic cross-sectional view illustrating a solar cell module in this disclosure. This is a schematic cross-sectional view illustrating a solar cell module in this disclosure.

[0012] Embodiments of this disclosure will be described below with reference to drawings and other figures. However, this disclosure can be implemented in many different ways and should not be interpreted as being limited to the embodiments described below. In addition, in order to make the explanation clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual form, but these are merely examples and should not limit the interpretation of this disclosure. Furthermore, in this specification and each figure, elements similar to those described above with respect to previously shown figures will be denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0013] In this specification, when describing a configuration in which one member is placed on top of another member, unless otherwise specified, the terms "on top" or "below" include both cases: when the other member is placed directly above or below the other member so as to be in contact with it, and when the other member is placed above or below the other member via yet another member. Similarly, in this specification, when describing a configuration in which one member is placed on the surface of another member, unless otherwise specified, the terms "on the surface" or "on the surface" include both cases: when the other member is placed directly above or below the other member so as to be in contact with it, and when the other member is placed above or below the other member via yet another member.

[0014] Furthermore, in this specification, terms such as "film," "sheet," and "substrate" are not distinguished from each other based on differences in terminology.

[0015] A. Wiring Concealment Sheet The wiring concealment sheet in this disclosure is placed inside the solar cell module. The wiring concealment sheet in this disclosure is a sheet that covers the wiring in the solar cell module so that it is not easily visible from the transparent surface protection member side.

[0016] Figure 1 is a schematic cross-sectional view illustrating a wiring concealment sheet in this disclosure. In Figure 1, the wiring concealment sheet 1 has a base layer 2, a colored layer 3, and an adhesive layer 4 in this order.

[0017] Figure 2 is a schematic cross-sectional view illustrating a solar cell module having a wiring concealment sheet according to this disclosure. In Figure 2, the solar cell module 20 includes, in this order, a surface protection member 21, a surface sealing material 22, solar cell elements 23, a back sealing material 25, and a back protection member 26. The solar cell elements 23 are of the back contact type, and wiring 24 connecting the solar cell elements 23 to each other is arranged on the back surface of the solar cell elements 23. Furthermore, a wiring concealment sheet 1 is arranged between the wiring 24 and the surface sealing material 22. That is, the wiring concealment sheet 1 is arranged inside the solar cell module 1. The wiring concealment sheet 1 is arranged such that the adhesive layer 4 faces the wiring 24 and the base layer 2 faces the surface sealing material 22.

[0018] In this disclosure, instead of directly forming a colored layer on the wiring, a wiring concealment sheet is placed on the wiring to make the wiring less noticeable and improve the appearance. Therefore, it is only necessary to add the wiring concealment sheet of this disclosure to each component that makes up a conventional solar cell module, which simplifies the manufacturing process and reduces manufacturing costs.

[0019] The wiring concealment sheets described in this disclosure will be explained below for each configuration.

[0020] 1. Arrangement of Wiring Concealing Sheet In this specification, "the wiring concealing sheet is arranged inside the solar cell module" means that the wiring concealing sheet is not arranged on the outermost side of the solar cell module. As described above, the wiring concealing sheet in this disclosure is a sheet that covers the wiring in the solar cell module so that it is not easily visible from the transparent surface protection member side. For this reason, it is preferable that the wiring concealing sheet in this disclosure is arranged inside the solar cell module, between the wiring and the surface sealant. Furthermore, if the solar cell module is a double-sided light-transmitting type, it is preferable that the wiring concealing sheet in this disclosure is arranged between the wiring and the surface sealant, as well as between the wiring and the back sealant.

[0021] Furthermore, the wiring concealment sheet in this disclosure is placed in the area where the wiring is located in the solar cell module. In other words, the wiring concealment sheet in this disclosure is not placed over the entire surface of the solar cell module, unlike surface protection members, surface sealants, back sealants, or back protection members. Conventionally, in order to give solar cell modules aesthetic appeal, the use of colored surface protection members, colored surface sealants, colored back sealants, or colored back protection members has been considered, but the wiring concealment sheet in this disclosure is different from these colored surface protection members, colored surface sealants, colored back sealants, and colored back protection members.

[0022] 2. Structure of the Wiring Concealing Sheet The wiring concealing sheet in this disclosure preferably has at least a colored layer, and more preferably has a base layer, a colored layer, and an adhesive layer in this order. In Figures 1 and 3, the wiring concealing sheet 1 has a base layer 2, a colored layer 3, and an adhesive layer 4 in this order. As shown in Figures 2 and 4, when such a wiring concealing sheet 1 is placed between the wiring 24 and the surface sealing material 22, the adhesive layer 4 is located on the outermost surface of the wiring concealing sheet 1 facing the wiring 24, so the adhesive layer 4 of the wiring concealing sheet 1 and the wiring 24 can be brought into close contact. On the other hand, in Figure 5, the wiring concealing sheet 1 has a base layer 2, an adhesive layer 4, and a colored layer 3 in this order. When such a wiring concealing sheet is placed between the wiring and the surface sealing material, since there is no adhesive layer 4 between the colored layer 3 and the wiring, the colored layer of the wiring concealing sheet and the wiring do not adhere closely, and a gap is created between the wiring concealing sheet and the wiring, so the appearance may not be very good. Therefore, the wiring concealment sheet in this disclosure preferably has a base layer, a colored layer, and an adhesive layer in this order.

[0023] Furthermore, if the wiring concealment sheet in this disclosure has a base layer, a colored layer, and an adhesive layer in this order, it is preferable that the wiring concealment sheet in this disclosure is arranged such that the adhesive layer faces the wiring and the base layer faces the surface sealing material.

[0024] The preferred structure of the wiring concealment sheet in this disclosure will be described below.

[0025] (1) Colored layer: It is preferable that the colored layer be placed between the base material layer and the adhesive layer.

[0026] The color of the colored layer is not particularly limited and can be any color, such as black, bluish-black, reddish-black, purplish-black, gray, brown, blue, bluish-purple, reddish-purple, purple, green, red, yellow, orange, white, etc. The colored layer may also be a dark color or white. If the colored layer is dark or white, the metallic luster of the wiring becomes less visible. Examples of dark colors include black, bluish-black, reddish-black, purplish-black, gray, brown, blue, bluish-purple, reddish-purple, and purple. Furthermore, the color of the colored layer may be the same color as or a similar color to the solar cell element. If the colored layer is the same color as or a similar color to the solar cell element, the wiring becomes less visible.

[0027] The colored layer preferably contains pigments and resins.

[0028] The pigment contained in the colored layer is appropriately selected according to the desired color of the colored layer. In particular, the pigment contained in the colored layer is preferably a near-infrared transmitting pigment. In a solar cell module having a wiring cover sheet, when the wiring cover sheet is placed on the wiring, a part of the colored layer of the wiring cover sheet may overlap a part of the solar cell element. In this case, the colored layer may cast a shadow on a part of the solar cell element, potentially causing a hot spot phenomenon. In contrast, by containing a near-infrared transmitting pigment in the colored layer, although some sunlight is absorbed, near-infrared rays are transmitted, thus suppressing the occurrence of a hot spot phenomenon caused by the colored layer. Therefore, it becomes possible to make the wiring less noticeable while suppressing hot spots.

[0029] Near-infrared transmitting pigments transmit near-infrared light. In this specification, "transmits near-infrared light" means transmits light with a wavelength of 750 nm to 1600 nm. The transmittance of the near-infrared transmitting pigment at wavelengths of 750 nm to 1600 nm is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more.

[0030] Near-infrared transmitting pigments are not particularly limited as long as they transmit near-infrared light, and examples include near-infrared transmitting dark pigments and near-infrared transmitting white pigments. Examples of near-infrared transmitting dark pigments include near-infrared transmitting black pigments, near-infrared transmitting blue pigments, and near-infrared transmitting brown pigments.

[0031] Examples of near-infrared transmitting black pigments include azo pigments. Examples of near-infrared transmitting blue pigments include phthalocyanine pigments. Phthalocyanine pigments are pigments that have a phthalocyanine skeleton and the concept also includes phthalocyanine to which various metals are coordinated. Examples of near-infrared transmitting brown pigments include benzimidazolone pigments, 4-[(2,5-dichlorophenyl)azo]-3-hydroxy-N-(2,5-dimethoxyphenyl)-2-naphthalenecarboxamide, 1-[(4-nitrophenyl)azo]-2-naphthalenol, bis[3-hydroxy-4-(phenylazo)-2-naphthalenecarboxylic acid]copper salt, N,N'-bis(2,4-dinitrophenyl)-3,3'-di Examples include methoxy-1,1'-biphenyl-4,4'-diamine, 3,4,9,10-perylenetetracarboxylic acid diimide, Δ2,2'(1H,1'H)-binaphtho[2,1-b]thiophene-1,1'-dione, and N,N'-(10,15,16,17-tetrahydro-5,10,15,17-tetraoxo-5H-dinaphtho[2,3-a:2'3'-i]carbazole-4,9-diyl)bis(benzamide). These near-infrared transmitting dark pigments may be used individually or in combination of two or more.

[0032] Other examples of near-infrared transmitting white pigments include titanium dioxide and aluminum hydroxide.

[0033] The pigment content in the colored layer is adjusted as appropriate according to the desired color and transmittance of the colored layer.

[0034] The resin contained in the colored layer preferably has durability, transparency, and printability, and can be appropriately selected from resins commonly used in pigment-containing inks. For example, polycarbonate-based polyurethane is preferably used.

[0035] The colored layer may contain additives as needed. Examples of additives include UV absorbers, light stabilizers, antioxidants, and plasticizers.

[0036] The colored layer may be disposed on the entire surface of the base material layer or may be disposed on a part of one surface of the base material layer. When the colored layer is disposed on a part of one surface of the base material layer, as shown in FIG. 3, it is preferable that the colored layer 3 is disposed at the central portion of one surface of the base material layer 2. As described above, in a solar cell module having a wiring hiding sheet, when the wiring hiding sheet is disposed on the wiring, a part of the colored layer of the wiring hiding sheet may be disposed so as to overlap a part of the solar cell element. In this case, a part of the solar cell element may be shaded by the colored layer, and there is a possibility that a hot spot phenomenon may occur. On the other hand, since the colored layer 3 is disposed at the central portion of one surface of the base material layer 2, as shown in FIG. 4, the area where the colored layer 3 of the wiring hiding sheet 1 and the solar cell element 23 overlap can be reduced. Therefore, the occurrence of the hot spot phenomenon due to the colored layer can be suppressed. Thus, it is possible to make the wiring inconspicuous while suppressing the hot spot.

[0037] Further, the colored layer may be disposed in a predetermined pattern or in a mesh pattern on one surface of the base material layer. In this case, since a part of the sunlight is transmitted through the opening of the colored layer, the occurrence of the hot spot phenomenon due to the colored layer can be suppressed. Thus, it is possible to make the wiring inconspicuous while suppressing the hot spot. The pattern shape of the colored layer is not particularly limited as long as the wiring can be made inconspicuous, and examples thereof include a stripe shape, a dot shape, and a lattice shape. The shape of the dot is not particularly limited, and examples thereof include a circular shape, an elliptical shape, a rectangular shape, and a polygonal shape. The shape of the opening of the lattice is also not particularly limited, and examples thereof include a circular shape, an elliptical shape, a rectangular shape, and a polygonal shape.

[0038] From the perspective of suppressing the above hot spots, the width of the colored layer is preferably narrower than the width of the base material layer. Further, the width of the colored layer is preferably narrower than the width of the adhesive layer. When the width of the colored layer is narrower than the width of the adhesive layer, that is, when the width of the adhesive layer is wider than the width of the colored layer, as shown in FIG. 4, in the solar cell module 20, when the wiring concealing sheet 1 is disposed between the wiring 24 and the surface sealing material 22, the adhesive layer 4 of the wiring concealing sheet 1 and the wiring 24 can be brought into closer contact with each other. On the other hand, the width of the colored layer is preferably wider than the width of the wiring portion to be concealed. This is because it facilitates the alignment of the wiring concealing sheet with respect to the wiring portion.

[0039] The width of the wiring portion to be concealed is appropriately selected according to the use of the wiring concealing sheet.

[0040] As illustrated in FIG. 4, in the solar cell module 20 having a back contact type solar cell element, when the wiring concealing sheet 1 is disposed on the wiring 24 connecting the solar cell elements 23 to each other, the width W1 of the wiring portion is the distance between the ends of the adjacent solar cell elements 23 located on the wiring 24 when the solar cell module 20 is viewed in plan from the surface protection member 21 side.

[0041] Also, as illustrated in FIGS. 6(a) to 6(c), in the solar cell module 20, when the wiring concealing sheet 1 is disposed on the wiring disposed on the light receiving surface side of the solar cell element 23, and when the bus bar 31 and the interconnect 32 are disposed on the light receiving surface side of the solar cell element 23 as the above wiring, the width W2 of the wiring portion is the wider one of the width of the bus bar 31 and the width of the interconnect 32. Note that FIG. 6(b) is a cross-sectional view taken along line A-A of FIG. 6(a), and FIG. 6(c) is a cross-sectional view taken along line B-B of FIG. 6(a). In FIG. 6(a), the surface protection member, the surface sealing material, the back surface sealing material, and the back surface protection member are omitted. In FIGS. 6(a) to 6(c), the bus bar 31 and the interconnect 32 are disposed on both the light receiving surface side and the non-light receiving surface side of the solar cell element 23.

[0042] Furthermore, as illustrated in Figures 7(a) to 7(b), when a wiring cover sheet 1 is placed on the current collection wiring in the solar cell module 20, and tab wires 33 are used as the current collection wiring, the width W3 of the wiring portion is the width of the tab wires 33. Note that Figure 7(b) is a cross-sectional view taken along line C-C in Figure 7(a). In Figure 7(a), the surface protection member, surface sealing material, back sealing material, and back protection member are omitted. In Figures 7(a) to 7(b), the tab wires 33 are connected to the interconnector 32 and are arranged around the outer circumference of the solar cell module 20.

[0043] Since the width of such wiring sections is usually several millimeters to several tens of millimeters, the width of the colored layer is preferably several millimeters to several tens of millimeters. Specifically, the width of the colored layer is preferably 1 mm to 100 mm, and may be 1 mm to 10 mm.

[0044] The thickness of the colored layer is, for example, 1 μm to 50 μm, but may also be 2 μm to 20 μm, or 3 μm to 10 μm. If the thickness of the colored layer is within the above range, the wiring can be sufficiently made inconspicuous. Furthermore, if the thickness of the colored layer is within the above range, it is possible to prevent the overall thickness of the wiring concealment sheet from becoming too thick, thereby improving the ability of the wiring concealment sheet to conform to uneven surfaces. Therefore, when a solar cell module is manufactured using the wiring concealment sheet, it is possible to prevent the formation of air gaps between the wiring concealment sheet and the wiring.

[0045] Here, the thickness of each layer is the average of 10 arbitrary thicknesses obtained by measuring the cross-section in the thickness direction of the wiring concealment sheet observed using a transmission electron microscope (TEM), scanning electron microscope (SEM), or scanning transmission electron microscope (STEM). Unless otherwise specified, the same method shall be used for measuring the thickness of other components.

[0046] The colored layer is preferably formed by printing an ink containing a pigment onto one side of the substrate layer, because this allows for a relatively thin colored layer. On the other hand, if a resin film containing a pigment is used as the colored layer, depending on the thickness of the resin film and the type of resin contained in the resin film, the rigidity of the resin film may cause gaps to form between the wiring concealment sheet and the wiring when a solar cell module is manufactured using a wiring concealment sheet. The printing method is not particularly limited and examples include offset printing, gravure printing, flexographic printing, letterpress printing, screen printing, inkjet printing, sublimation transfer printing, and melt transfer printing.

[0047] (2) Substrate layer The substrate layer in this disclosure is a member that supports the colored layer and the adhesive layer.

[0048] The substrate layer is preferably transparent. In this specification, "transparent" means that it is capable of transmitting visible light and near-infrared light. This can suppress the occurrence of hot spots caused by the wiring concealment sheet. Therefore, it becomes possible to make the wiring less noticeable while suppressing hot spots. Furthermore, since the wiring concealment sheet in this disclosure is used in solar cell modules, the substrate layer is preferably durable.

[0049] Furthermore, when heat-pressing each component of the solar cell module, it is preferable that the base material layer be meltable. This allows the wiring concealment sheet to adhere closely to the wiring during heat-pressing, further suppressing the formation of gaps between the wiring concealment sheet and the wiring.

[0050] The substrate layer may be a single layer or a multi-layered layer. The following explanation will cover the cases where the substrate layer is a single layer and where the sealing layer is a multi-layered layer.

[0051] (a) When the substrate layer is a single layer, the material of the substrate layer is preferably transparent, durable, and meltable, and a thermoplastic resin commonly used as a encapsulant for solar cell modules is preferably used. Examples include ethylene-vinyl acetate copolymer (EVA), polyolefin resin, polyvinyl butyral resin, silicone resin, and ionomer resin. Among these, polyolefin resin is preferred because of its excellent hydrolysis resistance.

[0052] Examples of polyolefin resins include polyethylene resin and polypropylene resin.

[0053] Polyethylene resins include not only ethylene homopolymers but also copolymers of ethylene and α-olefins.

[0054] Examples of polyethylene resins include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), metallocene-based linear low-density polyethylene (M-LLDPE), and very low-density polyethylene (VLDPE). Polyethylene resins may be used individually or in combination of two or more types. Among these, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and metallocene-based linear low-density polyethylene (M-LLDPE) are preferred due to their good flexibility.

[0055] The density of the polyethylene resin is not particularly limited; for example, 0.870 g / cm³. ３ Above, 0.930g / cm ３ The following is preferred: 0.880 g / cm³ ３ Above, 0.920g / cm ３ The following is more preferable: 0.890 g / cm³ ３ Above, 0.910g / cm ３ The following is even more preferable: By having the density of the polyethylene resin within the above range, flexibility, transparency, and processability can be improved. The density of the polyethylene resin is measured by Method B (pycnometer method) as specified in JIS K7112:1999.

[0056] In copolymers of ethylene and α-olefins, examples of α-olefins include those having 3 to 20 carbon atoms. Specifically, examples include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methylpentene-1, 4-methylhexene-1, and 4,4-dimethylpentene-1.

[0057] Specific examples of ethylene-α-olefin copolymers include ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, and ethylene-4-methylpentene-1 copolymer.

[0058] Polyethylene resin may be used alone or in combination of two or more types.

[0059] Examples of polypropylene resins include homopolypropylene resin (homoPP), which is a propylene homopolymer; random polypropylene resin (randomPP), which is a random copolymer of propylene and α-olefin; and block polypropylene resin (blockPP), which is a block copolymer. Polypropylene resins may be used individually or in combination of two or more types.

[0060] In the base layer, the polyolefin resin content is, for example, 50 parts by mass or more, 60 parts by mass or more, or 70 parts by mass or more, per 100 parts by mass of the total resin components contained in the base layer. Alternatively, the polyolefin resin content may be, for example, 100 parts by mass, 99 parts by mass or less, 95 parts by mass or less, or 90 parts by mass or less, per 100 parts by mass of the total resin components contained in the base layer. Specifically, the polyolefin resin content may be 100 parts by mass, 50 parts by mass or more and 99 parts by mass or less, 60 parts by mass or more and 95 parts by mass or less, or 70 parts by mass or more and 90 parts by mass or less, per 100 parts by mass of the total resin components contained in the base layer.

[0061] The substrate layer may contain additives as needed. Examples of additives include UV absorbers, light stabilizers, antioxidants, antiblocking agents, and lubricants.

[0062] The proportion of each resin component contained in each layer of the wiring concealment sheet can be analyzed, for example, from the peak ratio detected by scanning calorimetry (DSC), infrared spectroscopy (IR), nuclear magnetic resonance (NMR), etc.

[0063] The thickness of the substrate layer is, for example, 20 μm to 300 μm, but may also be 30 μm to 200 μm, or 50 μm to 100 μm. Transparency and handling can be ensured if the thickness of the substrate layer is within the above range. Furthermore, if the thickness of the substrate layer is within the above range, when manufacturing solar cell modules using a wiring concealment sheet, positional displacement due to localized pressure during vacuum lamination can be suppressed, thereby reducing appearance defects.

[0064] One example of a method for producing the base layer is extrusion molding.

[0065] The adhesive layer-side surface of the substrate layer may be surface-treated. This can improve adhesion to the adhesive layer. The surface treatment is not particularly limited and includes corona treatment, plasma treatment, ultraviolet treatment, electron beam treatment, flame treatment, etc. Among these, corona treatment is preferred in terms of reducing processing costs and damage to the substrate layer.

[0066] (b) When the base layer is multilayered, examples of the layer configuration of the base layer include two layers of type 2, three layers of type 2, and three layers of type 3.

[0067] In the case of a multilayer structure, it is preferable that the base layer has, in order from the adhesive layer side, a meltable first layer and a second layer that supports the first layer.

[0068] (i) The material of the first layer is preferably transparent, durable, and meltable, and a thermoplastic resin commonly used as a encapsulant for solar cell modules is preferably used. The thermoplastic resin is the same as the material of the single-layer base layer described above. Among these, polyolefin resin is preferred because of its excellent hydrolysis resistance. Furthermore, polyethylene resin is preferred because of its excellent flexibility.

[0069] In the first layer, the polyethylene resin content is, for example, 50 parts by mass or more, 60 parts by mass or more, or 70 parts by mass or more, based on 100 parts by mass of all resin components contained in the first layer. Alternatively, the polyethylene resin content may be, for example, 100 parts by mass, 99 parts by mass or less, 95 parts by mass or less, or 90 parts by mass or less, based on 100 parts by mass of all resin components contained in the first layer. Specifically, the polyethylene resin content may be 100 parts by mass, 50 parts by mass or more and 99 parts by mass or less, 60 parts by mass or more and 95 parts by mass or less, or 70 parts by mass or more and 90 parts by mass or less, based on 100 parts by mass of all resin components contained in the first layer.

[0070] Furthermore, if the first layer contains polyethylene resin and the second layer contains polypropylene resin, the first layer may further contain polypropylene resin in addition to polyethylene resin. This can improve the adhesion between the first and second layers.

[0071] The same applies to polyethylene resin and polypropylene resin as described in the section on single-layer substrates above.

[0072] Furthermore, if the first layer contains polyethylene resin and the second layer contains polypropylene resin, the first layer may further contain a compatibilizer. This can improve the adhesion between the first and second layers. The compatibilizer is not particularly limited as long as it is a material that can make polyethylene resin and polypropylene resin compatible. Examples of compatibilizers include olefin-based elastomers and olefin-based plastomers. Specifically, examples include polypropylene-based elastomers and polyethylene-based elastomers.

[0073] Examples of polypropylene-based elastomers include copolymers of propylene and α-olefins other than propylene (hereinafter sometimes referred to as propylene-α-olefin copolymers). The α-olefins other than propylene that constitute the propylene-α-olefin copolymer may be one type or two or more types. Furthermore, commercially available polypropylene-based elastomers may be used, for example. Specifically, examples include "Tafmer PN-0040" and "Tafmer PN-2060" manufactured by Mitsui Chemicals, Inc.

[0074] Examples of polyethylene-based elastomers include copolymers of ethylene and α-olefins other than ethylene (hereinafter sometimes referred to as ethylene-α-olefin copolymers). The α-olefins other than ethylene that constitute the ethylene-α-olefin copolymer may be one type or two or more types. In addition, commercially available polyethylene-based elastomers may be used, for example. Specifically, examples include "Tafmer DF-110" and "Tafmer DF-640 (product name)" manufactured by Mitsui Chemicals, Inc.

[0075] In the first layer, the content of the compatibilizer may be, for example, 0.1 parts by mass or more, and may be 0.5 parts by mass or more, based on 100 parts by mass of the total resin components contained in the first layer. Furthermore, the content of the compatibilizer may be, for example, less than 5 parts by mass, 4 parts by mass or less, 3 parts by mass or less, or 2 parts by mass or less, based on 100 parts by mass of the total resin components contained in the first layer. Specifically, the content of the compatibilizer may be 0.1 parts by mass or more and less than 5 parts by mass, 0.1 parts by mass or more and 4 parts by mass or less, 0.5 parts by mass or more and 3 parts by mass or less, or 0.5 parts by mass or more and 2 parts by mass or less, based on 100 parts by mass of the total resin components contained in the first layer.

[0076] The first layer may contain additives as needed. Examples of additives include UV absorbers, light stabilizers, antioxidants, antiblocking agents, and lubricants.

[0077] The thickness of the first layer is, for example, 10 μm to 150 μm, may be 15 μm to 100 μm, or 25 μm to 50 μm. If the thickness of the first layer is within the above range, transparency and handling properties can be ensured. Furthermore, if the thickness of the first layer is within the above range, when manufacturing a solar cell module using a wiring concealment sheet, positional displacement due to localized pressure during vacuum lamination can be suppressed, thereby reducing appearance defects.

[0078] (ii) Second layer The material of the second layer is preferably transparent and durable, and a thermoplastic resin is used. Examples of thermoplastic resins include polyolefin resin, polyester resin, and fluororesin. Examples of polyolefin resins include polyethylene resin and polypropylene resin. Examples of polyester resins include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT). Among these, polyolefin resin and polyester resin are preferred from a cost perspective. Polyolefin resin is particularly preferred from the viewpoint of flexibility. Among polyolefin resins, polypropylene resin is preferred from the viewpoint of heat resistance.

[0079] In the second layer, the polypropylene resin content is, for example, 50 parts by mass or more, 60 parts by mass or more, 65 parts by mass or more, or 70 parts by mass or more, based on 100 parts by mass of all resin components contained in the second layer. Alternatively, the polypropylene resin content may be, for example, 100 parts by mass, 90 parts by mass or less, 80 parts by mass or less, or 75 parts by mass or less, based on 100 parts by mass of all resin components contained in the second layer. Specifically, the polypropylene resin content may be 100 parts by mass, 50 parts by mass or more and 90 parts by mass or less, 60 parts by mass or more and 80 parts by mass or less, 65 parts by mass or more and 80 parts by mass or less, or 70 parts by mass or more and 75 parts by mass or less, based on 100 parts by mass of all resin components contained in the second layer.

[0080] Furthermore, if the first layer contains polyethylene resin and the second layer contains polypropylene resin, the second layer may further contain polyethylene resin in addition to polypropylene resin. This can improve the adhesion between the first and second layers.

[0081] The same applies to polyethylene resin and polypropylene resin as described in the section on single-layer substrates above.

[0082] Furthermore, if the first layer contains polyethylene resin and the second layer contains polypropylene resin, the second layer may further contain a compatibilizer. This can improve the adhesion between the first and second layers. The compatibilizer is not particularly limited as long as it is a material that can make polyethylene resin and polypropylene resin compatible. The compatibilizer is the same as described in the section on the first layer above.

[0083] In the second layer, the content of the compatibilizer may be, for example, 1 part by mass or more, and may be 5 parts by mass or more, per 100 parts by mass of the total resin components contained in the second layer. Furthermore, the content of the compatibilizer may be, for example, less than 50 parts by mass, 40 parts by mass or less, 30 parts by mass or less, or 20 parts by mass or less, per 100 parts by mass of the total resin components contained in the second layer. Specifically, the content of the compatibilizer may be 1 part by mass or more and less than 50 parts by mass, 1 part by mass or more and 40 parts by mass or less, 5 parts by mass or more and 30 parts by mass or less, or 5 parts by mass or more and 20 parts by mass or less, per 100 parts by mass of the total resin components contained in the second layer.

[0084] The second layer may contain additives as needed. Examples of additives include UV absorbers, light stabilizers, antioxidants, antiblocking agents, and lubricants.

[0085] The thickness of the second layer is, for example, 10 μm to 150 μm, may be 15 μm to 100 μm, or 25 μm to 50 μm. If the thickness of the second layer is within the above range, transparency and handling properties can be ensured. Furthermore, if the thickness of the second layer is within the above range, when manufacturing solar cell modules using a wiring concealment sheet, positional displacement due to localized pressure during vacuum lamination can be suppressed, thereby reducing appearance defects.

[0086] (iii) The third base layer may have a third layer between the first and second layers. The third layer may be an adhesive layer for bonding the first and second layers. The adhesive may be an adhesive used for bonding general films. The adhesive may also be a dry laminating adhesive or an anchor coating agent for extrusion laminating. The thickness of the third layer is not particularly limited as long as transparency is achieved.

[0087] Furthermore, if the first layer contains polyethylene resin and the second layer contains polypropylene resin, the third layer may be a layer containing both polyethylene resin and polypropylene resin.

[0088] (iv) Method for preparing the base layer Examples of methods for preparing the base layer include extrusion molding, extrusion lamination, co-extrusion, and dry lamination.

[0089] (3) Adhesive layer The adhesive used in the adhesive layer is not particularly limited as long as it can adhere tightly to the wiring cover sheet, the wiring and the solar cell elements, and is transparent and durable; a general adhesive can be used.

[0090] The adhesive layer may contain a silane coupling agent. This can improve the adhesion between the adhesive layer and the wiring and solar cell elements. As the silane coupling agent, for example, a silane coupling agent used in the encapsulant of solar cell modules can be used. The silane coupling agent may be used alone or in combination of two or more types. The content of the silane coupling agent in the adhesive layer may be, for example, 5% by mass or less.

[0091] The adhesive layer may contain additives as needed. Examples of additives include UV absorbers, light stabilizers, and antioxidants.

[0092] The adhesive layer preferably has repositionable properties. This allows the wiring cover sheet to be repositioned when placed on the wiring. It also makes the wiring cover sheet less likely to tear when repositioned. Furthermore, it makes it easier to adjust the position when applying the wiring cover sheet.

[0093] In the wiring concealment sheet of this disclosure, the adhesive strength to the silicon solar cell element is preferably, for example, 1 N / 15 mm or more and 20 N / 15 mm or less, more preferably 2 N / 15 mm or more and 15 N / 15 mm or less, and even more preferably 3 N / 15 mm or more and 10 N / 15 mm or less. If the adhesive strength is within the above range, re-peelability can be obtained. Furthermore, if the adhesive strength is within the above range, displacement and peeling of the wiring concealment sheet can be suppressed.

[0094] The adhesive strength of the wiring concealment sheet to the silicon solar cell element will be measured in accordance with JIS Z0237:2022. However, the test specimen and test board will be as follows. First, the wiring concealment sheet will be cut to a size of 15 mm in width and 70 mm in length to obtain a test specimen. Next, the test specimen will be attached to the silicon cell and pressed firmly by rolling a 2 kg roller back and forth once. Then, it will be left for 1 hour in an environment of 23°C and 50% RH. Next, the test specimen will be peeled off the silicon solar cell element at a peeling angle of 180° and a peeling speed of 300 mm / min, and the adhesive strength will be measured. An n-type single-crystal silicon cell will be used as the silicon solar cell element.

[0095] The thickness of the adhesive layer is, for example, 2 μm to 100 μm, but may also be 4 μm to 50 μm, or 6 μm to 25 μm. If the thickness of the adhesive layer is within the above range, re-peelability is easily obtained. In addition, if the thickness of the adhesive layer is within the above range, displacement and peeling of the wiring concealment sheet can be suppressed.

[0096] (4) Release film In the wiring concealment sheet of this disclosure, a release film may be placed on the side opposite to the colored layer of the adhesive layer. A general-purpose release film can be used as the release film. When using the wiring concealment sheet, the release film is peeled off.

[0097] 3. Wiring Concealing Sheet The wiring concealing sheet in this disclosure preferably transmits near-infrared light. This can suppress the generation of hot spots caused by the wiring concealing sheet. The transmittance of the wiring concealing sheet at wavelengths of 750 nm to 1600 nm is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more. The transmittance at wavelengths of 750 nm to 1600 nm is the average value of the transmittance in the above wavelength range. The transmittance at wavelengths of 750 nm to 1600 nm is measured using a spectrophotometer.

[0098] Furthermore, the wiring concealment sheet in this disclosure preferably transmits visible light. When a colored layer is arranged on a part of one side of the substrate layer, the transmittance in the region of the wiring concealment sheet where the colored layer is not arranged, at wavelengths of 400 nm to 1600 nm, is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more. The transmittance at wavelengths of 400 nm to 1600 nm is the average value of the transmittance in the above wavelength range. The transmittance at wavelengths of 400 nm to 1600 nm is measured using a spectrophotometer.

[0099] The width of the wiring concealment sheet in this disclosure is appropriately selected according to the width of the wiring portion to be concealed. As described above, the width of the wiring portion to be concealed is usually several millimeters to several tens of millimeters. Therefore, the width of the wiring concealment sheet is preferably on the order of millimeters. Specifically, the width of the wiring concealment sheet is preferably 1 mm or more and 100 mm or less, and may be 1 mm or more and 10 mm or less.

[0100] The wiring concealment sheet in this disclosure is used in a solar cell module to cover the wiring so that it is not easily visible from the transparent surface protection member side. Examples of wiring to be concealed include wiring located in areas where solar cell elements are not arranged, and wiring located on the light-receiving surface side of solar cell elements. Specifically, as shown in Figure 4, in a solar cell module 20 having back-contact type solar cell elements, the wiring concealment sheet 1 may be placed on the wiring 24 connecting the solar cell elements 23. Also, as shown in Figures 6(a) to 6(c), in a solar cell module 20, the wiring concealment sheet 1 may be placed on the wiring located on the light-receiving surface side of the solar cell elements 23. The wiring in question is a busbar 31 and an interconnector 32 located on the light-receiving surface side of the solar cell elements 23. Furthermore, as shown in Figures 7(a) to 7(b), in a solar cell module 20, the wiring concealment sheet 1 may be placed on the current-collecting wiring. The current-collecting wiring is a tab wire 33.

[0101] B. Solar Cell Module In the solar cell module of this disclosure, the above-mentioned wiring concealment sheet is arranged inside the solar cell module.

[0102] Figure 2 is a schematic cross-sectional view illustrating a solar cell module in this disclosure. In Figure 2, the solar cell module 20 includes, in this order, a surface protection member 21, a surface sealing material 22, solar cell elements 23, a back sealing material 25, and a back protection member 26. The solar cell elements 23 are of the back contact type, and wiring 24 connecting the solar cell elements 23 to each other is arranged on the back surface of the solar cell elements 23. Furthermore, a wiring concealment sheet 1 is arranged between the wiring 24 and the surface sealing material 22. That is, the wiring concealment sheet 1 is arranged inside the solar cell module 1. The wiring concealment sheet 1 is arranged such that the adhesive layer 4 faces the wiring 24 and the base layer 2 faces the surface sealing material 22.

[0103] The solar cell module in this disclosure provides the same effects as those described in section A, "Wiring Concealment Sheet," above.

[0104] The following describes the solar cell modules in this disclosure, broken down by their configuration.

[0105] 1. Wiring Concealment Sheets The wiring concealment sheets are the same as those described in section A. Wiring Concealment Sheets above.

[0106] The wiring concealment sheet is placed inside the solar cell module. The placement of the wiring concealment sheet is the same as described in section A. Wiring Concealment Sheet 1. Placement of Wiring Concealment Sheet above.

[0107] Furthermore, if the solar cell module is a double-sided light-transmitting type, it is preferable to place a wiring cover sheet on top of the interconnects or busbars located on the back side of the solar cell elements in order to improve the appearance from the back side of the solar cell module.

[0108] 2. Solar Cell Elements General-purpose solar cell elements can be used as solar cell elements. Examples of solar cell elements include monocrystalline silicon solar cell elements, polycrystalline silicon solar cell elements, amorphous silicon solar cell elements, compound semiconductor solar cell elements, dye-sensitized solar cell elements, quantum dot solar cell elements, and organic thin-film solar cell elements. The size and shape of the solar cell elements can be appropriately selected according to the application of the solar cell module.

[0109] 3. Surface protection member and back protection member The surface protection member and back protection member are members that protect the solar cell element.

[0110] The surface protection member is placed on the light-receiving side of the solar cell module. A common surface protection member for solar cell modules can be used as the surface protection member. For example, a glass substrate can be used.

[0111] The back-side protective member may or may not be transparent. If the back-side protective member is transparent, both sides of the solar cell module can be used as light-receiving surfaces. A general-purpose back-side protective member for solar cell modules can be used as the back-side protective member.

[0112] 4. Surface and back surface sealants General sealants used in solar cell modules can be used as surface and back surface sealants, such as ethylene-vinyl acetate copolymer (EVA), polyolefin resin, polyvinyl butyral resin, silicone resin, and ionomer resin.

[0113] The thickness of the surface sealant and the back sealant are selected appropriately according to the type and size of the solar cell module.

[0114] 5. Method for Manufacturing Solar Cell Modules The method for manufacturing solar cell modules in this disclosure includes a step of stacking the components of the solar cell module and then heat-pressing them together. Known methods can be used as the heat-pressing method, for example, the vacuum thermal lamination method. In the heat-pressing step, the components of the solar cell module are integrated together.

[0115] The conditions for the vacuum thermal lamination method can be appropriately selected according to the size of the solar cell module, the type of each component, etc., and are not particularly limited. The heating temperature is, for example, 130°C to 170°C. The holding time is, for example, 3 minutes to 30 minutes.

[0116] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of this disclosure and achieves similar effects is included within the technical scope of this disclosure.

[0117] [Example 1] (1) Preparation of the base layer A resin composition for forming the first and second layers constituting the base layer was prepared using the resin components and additives shown below.

[0118] Homopolypropylene: Density 0.900 g / cm³ ３ Melting point 165°C, MFR 4g / 10min at 230°C. Linear low-density polyethylene (LLDPE) 1: Density 0.905g / cm³ ３ Melting point 94°C, softening point 82°C, MFR 1.2 g / 10 min at 190°C. Linear low-density polyethylene (LLDPE) 2: Density 0.901 g / cm³３ , silane-modified polyethylene resin with a melting point of 93 °C, a softening point of 80 °C, and an MFR of 2 g / 10 min at 190 °C: density 0.900 g / cm ３ , 2 parts by mass of vinyltrimethoxysilane and 0.1 part by mass of dicumyl peroxide as a radical generator (reaction catalyst) were mixed with 98 parts by mass of metallocene linear low-density polyethylene (M-LLDPE) having an MFR of 1.2 g / 10 min at 190 °C, melted and kneaded at 200 °C, and density 0.903 g / cm ３ , a silane-modified polyethylene resin with a melting point of 90 °C and an MFR of 1 g / 10 min at 190 °C was obtained. ・Hindered amine light stabilizer (HALS): molecular weight 35000, density 0.930 g / cm ３ , polypropylene-based elastomer (compatibilizer) with a melting point of 110 °C and an MFR of 3 g / 10 min at 190 °C: density 0.876 g / cm ３ , weather-resistant masterbatch (MB) with a melting point of 160 °C, a softening point of 120 °C, and an MFR of 3 g / 10 min at 230 °C: density 0.900 g / cm ３ , 5 parts by mass of a hindered amine light stabilizer was mixed with 100 parts by mass of a powder obtained by pulverizing a polypropylene-based elastomer of, melted, processed, and pelletized to obtain a masterbatch.

[0119] Using an extruder equipped with a T-die, the above-described resin composition was melted at 190 °C and co-extruded to obtain a base material layer having a first layer and a second layer. The total thickness of the base material layer was 80 μm, the thickness of the first layer was 40 μm, the thickness of the second layer was 40 μm, and the width of the base material layer was 1100 mm. Next, corona treatment was performed on the surface of the base material layer on the first layer side.

[0120]

[0121] (2) Formation of the colored layer A resin composition for the colored layer having the following composition was prepared. <Composition of the resin composition for the colored layer> ・Polycarbonate-based main agent (manufactured by Rock Paint Co., Ltd. "CORM-9", containing phthalocyanine blue and pigment brown 25 which are near-infrared transmitting pigments): 15 parts by mass ・Isocyanate-based curing agent (manufactured by Rock Paint Co., Ltd. "H-51"): 0.5 parts by mass

[0122] Using a gravure coating method, the above-mentioned resin composition for the colored layer was applied in stripes with a width of 2 mm and a pitch of 6 mm onto the first layer of the substrate layer, and dried to form a colored layer with a thickness of 5.7 μm.

[0123] (3) Formation of the adhesive layer An adhesive composition with the following composition was prepared. <Composition of the adhesive composition> ・Acrylic urethane adhesive (Sohken Chemical Co., Ltd. "1502CDTGB", containing tackifier): 100 parts by mass ・Isocyanate curing agent (Rock Paint Co., Ltd. "E-AX"): 0.1 parts by mass ・Silane coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM403"): 1 part by mass ・HALS (ADEKA Corporation "LA-24"): 1 part by mass ・Antioxidant (ADEKA Corporation "AO-60G"): 1 part by mass

[0124] Using a gravure coating method, the adhesive composition was applied to cover the colored layer and dried to form an adhesive layer with a thickness of 10.6 μm. This resulted in obtaining a wiring concealment sheet having a base layer, a colored layer, and an adhesive layer in that order. Subsequently, the 1100 mm wide wiring concealment sheet was micro-slit to a width of 6 mm.

[0125] [Example 2] (1) Preparation of the base layer A base layer was obtained in the same manner as in Example 1.

[0126] (2) Formation of the adhesive layer Using the same adhesive composition as in Example 1, the adhesive composition was applied to the entire surface of the first layer side of the base material layer to form an adhesive layer with a thickness of 10 μm.

[0127] (3) Formation of the colored layer A black polyethylene terephthalate (PET) film with a thickness of 50 μm and a width of 1100 mm was prepared. The black PET film was placed on the adhesive layer. This resulted in obtaining a wiring concealment sheet having a base layer, an adhesive layer, and a colored layer in that order. Subsequently, the 1100 mm wide wiring concealment sheet was micro-slit to a width of 6 mm.

[0128] [Evaluation] (1) Using a transmittance spectrophotometer (JASCO "V-670"), the transmittance of the wiring concealment sheet was measured at wavelengths of 400 nm to 1600 nm in the region where the colored layer was placed and in the region where the colored layer was not placed. In Example 2, the above transmittance of the laminate of the base layer and adhesive layer was measured and used as the above transmittance of the region where the colored layer was not placed.

[0129]

[0130] (2) A glass substrate with an external thickness of 3.2 mm, a surface sealing sheet with a thickness of 450 μm (Dai Nippon Printing Co., Ltd. "CVF"), a wiring concealment sheet with a width of 6 mm, a 5-inch back-contact type solar cell element (Sunpower monocrystalline silicon cell), a back-side sealing sheet with a thickness of 450 μm (Dai Nippon Printing Co., Ltd. "CVF"), and a back-side protective sheet (Dai Nippon Printing Co., Ltd. "PV-BS BE180-bR"). In the back-contact type solar cell element, the solar cells were connected by aluminum wiring placed on the back of the solar cell element. Also, when viewing the solar cell element from above, the distance between the ends of adjacent solar cell elements located on the wiring was 1.9 mm. When laminating each component, the wiring concealment sheet was positioned so that the adhesive layer of the wiring concealment sheet faced the wiring connecting the solar cell elements, and the substrate layer faced the surface sealing sheet. Next, a vacuum laminator was used to perform vacuum lamination under the following conditions: set temperature of 150°C, vacuum evacuation for 5 minutes, pressing for 7 minutes, and pressure of 100 kPa, to fabricate a solar cell module.

[0131] The appearance of the solar cell module was visually inspected. In the solar cell module using the wiring concealment sheet of Example 1, the aluminum wiring was not visible, and the color of the solar cell element matched the color of the wiring concealment sheet. Furthermore, the appearance of the area where the wiring concealment sheet was placed was good. In addition, when the cross-section of the solar cell module was observed using a scanning electron microscope (SEM), it was confirmed that the wiring concealment sheet and the aluminum wiring were in close contact, and there was no gap between the wiring concealment sheet and the aluminum wiring.

[0132] Furthermore, in the solar cell module using the wiring concealment sheet in Example 2, the aluminum wiring was not visible, and the color of the solar cell element matched the color of the wiring concealment sheet. On the other hand, the appearance of the area where the wiring concealment sheet was placed was not very good. When the cross-section of the solar cell module was observed using a SEM, it was confirmed that there was an air gap between the wiring concealment sheet and the aluminum wiring. This air gap is thought to be the cause of the poor appearance.

[0133] (3) Adhesive strength The adhesive strength of the wiring concealment sheet was measured in accordance with JIS Z0237:2022. However, the test specimens and test boards were as follows. First, the wiring concealment sheet was cut to a size of 15 mm in width and 70 mm in length to obtain a test specimen. Next, the test specimen was attached to the test board and pressed firmly by rolling a 2 kg roller back and forth once. Subsequently, it was left for 1 hour in an environment of 23°C and 50% RH. Next, the test specimen was peeled off the test board at a peeling angle of 180° and a peeling speed of 300 mm / min, and the adhesive strength was measured. As test boards, a silicon solar cell element (n-type single crystal silicon cell) and an aluminum plate (simulating an aluminum electrode) were used.

[0134]

[0135] This disclosure provides the following inventions: [1] A wiring concealment sheet disposed inside a solar cell module. [2] The wiring concealment sheet according to [1], having a base layer, a colored layer, and an adhesive layer in that order. [3] The wiring concealment sheet according to [2], wherein the colored layer contains a near-infrared transmitting pigment. [4] The wiring concealment sheet according to [1] or [2], wherein the transmittance of the wiring concealment sheet at a wavelength of 750 nm to 1600 nm is 50% or more. [5] The wiring concealment sheet according to any one of [2] to [4], wherein the width of the colored layer is narrower than the width of the base layer and narrower than the width of the adhesive layer. [6] The wiring concealment sheet according to any one of [2] to [5], wherein the base layer contains a polyolefin resin. [7] A solar cell module in which the wiring concealment sheet according to any one of [1] to [6] is disposed inside the solar cell module. [8] The solar cell module according to [7], comprising a surface protective member, a surface sealing material, a solar cell element, a back sealing material, and a back protective member in this order, wherein wiring is arranged between the surface sealing material and the back sealing material, and the wiring concealment sheet is arranged between the surface sealing material and the wiring.

[0136] 1… Wiring concealment sheet 2… Base layer 3… Colored layer 4… Adhesive layer 20… Solar cell module 21… Surface protective material 22… Surface sealing material 23… Solar cell element 24… Wiring 25… Back sealing material 26… Back protective material

Claims

1. Wiring concealment sheet placed inside the solar panel module.

2. The wiring concealment sheet according to claim 1, comprising a base layer, a colored layer, and an adhesive layer in that order.

3. The wiring concealment sheet according to claim 2, wherein the colored layer contains a near-infrared transmitting pigment.

4. The wiring concealment sheet according to claim 2, wherein the transmittance of the wiring concealment sheet at wavelengths of 750 nm to 1600 nm is 50% or more.

5. The wiring concealment sheet according to claim 2, wherein the width of the colored layer is narrower than the width of the base material layer and narrower than the width of the adhesive layer.

6. The wiring concealment sheet according to claim 2, wherein the base layer contains a polyolefin resin.

7. A solar cell module in which a wiring concealment sheet according to any one of claims 1 to 6 is disposed inside the solar cell module.

8. The solar cell module according to claim 7, comprising a surface protective member, a surface sealing material, a solar cell element, a back sealing material, and a back protective member in this order, wherein wiring is arranged between the surface sealing material and the back sealing material, and the wiring concealment sheet is arranged between the surface sealing material and the wiring.

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