JP2019145554A - Solar cell module - Google Patents

Abstract

To provide a solar cell module which achieves high efficiency of a solar cell module and ensuring of adhesion between the protective glass and filler layer.SOLUTION: Disclosed is a solar cell module in which a back sheet, a first filler layer, a photoelectric conversion element electrically connected to an electrode, a second filler layer, and protective glass are laminated in this order. The second filler layer is a sheet in which a plurality of particulate phosphors are unevenly distributed on a protective glass side in a UV absorber-containing resin. In distribution of phosphors in the sheet, a filling ratio of the outermost surface on the protective glass side is 30% by volume or more and 55% by volume or less. There is a surface arranged by closest-packing in a plane perpendicular to the depth direction of the sheet.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solar cell module.

  A solar cell module generally has low sensitivity characteristics in a short wavelength region, and cannot effectively use light in a short wavelength region such as ultraviolet rays contained in sunlight. Efforts to improve the efficiency of the solar cell module by absorbing the light in the short wavelength region and using the phosphor that emits fluorescence in the long wavelength region as a wavelength conversion material, increasing the amount of light in the long wavelength region with high sensitivity characteristics It has been done conventionally.

  On the other hand, since the photoelectric conversion element of the solar cell module is deteriorated by being irradiated with ultraviolet rays for a long time, it is desirable that ultraviolet rays are removed from the light reaching the photoelectric conversion element as much as possible. The material contains a UV absorber. It is not necessary to use an ultraviolet absorber if it can absorb ultraviolet rays sufficiently with only phosphors, but in many cases, phosphors alone cannot absorb ultraviolet rays sufficiently. It is necessary to use an agent together.

  However, mixing the phosphor and the ultraviolet absorber in the filler that protects the photoelectric conversion element causes the ultraviolet absorber to absorb the light in the ultraviolet region that the phosphor absorbs. This results in a decrease in the amount of emitted light and hinders higher efficiency by wavelength conversion.

  Therefore, for example, in Patent Document 1, an ultraviolet absorber is blended in an organic resin that sandwiches a photoelectric conversion element, and the phosphor is disposed on the light incident surface side of the front protective glass, thereby Avoid mixing phosphors. Further, in Patent Document 2, by placing a filler layer containing a phosphor on the upper part of a filler layer containing an ultraviolet absorber, ultraviolet rays are first absorbed by the filler layer containing the upper phosphor, and fluorescent light emission is performed. The lower ultraviolet absorber layer absorbs the ultraviolet rays that could not be absorbed. Thereby, it is trying to achieve both high efficiency by the phosphor and ultraviolet absorption by the ultraviolet absorber.

JP 2012-191068 A International Publication Number WO2015 / 129177

  However, in the configuration of Patent Document 1, another layer that holds the phosphor is formed on the light incident surface side of the protective glass. Therefore, the phosphor layer is exposed to the outdoor environment, and there is a problem that the phosphor is rapidly deteriorated. Moreover, in the structure of patent document 2, according to examination of this inventor, an ultraviolet absorber will spread | diffuse with progress of time from the layer containing an ultraviolet absorber to the layer containing a fluorescent substance. As a result, there is a problem that, as viewed from the phosphor, the ultraviolet absorber also circulates on the light incident surface side, so that the amount of light emitted from the phosphor is reduced and the efficiency is hindered. Therefore, if the amount of the phosphor is increased in order to ensure the light emission amount of the phosphor, the adhesiveness between the protective material glass and the filler containing the phosphor is lowered, so that the adhesion is secured while ensuring the light emission amount. Has a problem that cannot be secured.

  The present invention solves the above-mentioned conventional problems, and aims to provide a solar cell module that achieves both high efficiency of the solar cell module and ensuring adhesion between the protective glass and the filler layer. To do.

In order to achieve the above object, a solar cell module according to the present invention includes:
A backsheet,
A first filler layer;
An electrode and a photoelectric conversion element connected to the electrode;
A second filler layer;
Protective glass,
Is a solar cell module having a structure laminated in the above order,
The second filler layer is a sheet in which a plurality of particulate phosphors are unevenly distributed on the protective glass side in the ultraviolet absorber-containing resin,
As for the distribution of the phosphor in the sheet, the packing ratio is 30% by volume or more and 55% by volume or less on the outermost surface on the protective glass side, and the packing is closest packed in a plane perpendicular to the depth direction of the sheet. There is a surface that is placed.

  As described above, according to the solar cell module of the present invention, in the second filler layer disposed on the light incident side of the photoelectric conversion element, the phosphor is placed in the ultraviolet absorber-containing resin on the protective glass side. The distribution of the phosphor is such that the filling rate is 30% by volume or more and 55% by volume or less on the outermost surface on the protective glass side, and is the highest in the plane perpendicular to the depth direction of the second filler layer. There are faces that are arranged in close packing. Further, by making the phosphor unevenly distributed on the protective glass side, the proportion of the ultraviolet absorber present on the protective glass side, that is, on the light incident surface side, is reduced as seen from the phosphor, thereby increasing the light emission amount of the phosphor. be able to. Moreover, the adhesiveness of protective glass and a 2nd filler layer can be improved by controlling the filling rate of the fluorescent substance arrange | positioned on the outermost surface by the side of protective glass. Thereby, it can be set as the solar cell module which ensured the high efficiency by wavelength conversion, and the adhesiveness of the protective glass and the 2nd filler layer.

It is sectional drawing of the solar cell module 100 in embodiment. In the method for manufacturing solar cell module 100 in the embodiment, the back sheet, the first filler layer, the photoelectric conversion element electrically connected to the electrode, the second filler layer, the protective glass, It is sectional drawing which shows the state which has arrange | positioned in the said order. In the manufacturing method of the solar cell module 100 in embodiment, it is sectional drawing which shows the state which embeds fluorescent substance in the ultraviolet absorber containing resin by closest packing. In the manufacturing method of the solar cell module 100 in embodiment, it is sectional drawing which shows the state which has arrange | positioned fluorescent substance by the closest packing to ultraviolet absorber containing resin. In the manufacturing method of the solar cell module 100 in embodiment, it is sectional drawing which shows the state which embeds fluorescent substance in ultraviolet absorber containing resin with the filling rate of 30 volume% or more and 55 volume% or less. In the manufacturing method of the solar cell module 100 in embodiment, it is sectional drawing which shows the state which has arrange | positioned fluorescent substance to the ultraviolet absorber containing resin by 30 to 55 volume% of filling rates.

The solar cell module according to the first aspect includes a back sheet,
A first filler layer;
An electrode and a photoelectric conversion element connected to the electrode;
A second filler layer;
Protective glass,
Is a solar cell module having a structure laminated in the above order,
The second filler layer is a sheet in which a plurality of particulate phosphors are unevenly distributed on the protective glass side in the ultraviolet absorber-containing resin,
As for the distribution of the phosphor in the sheet, the packing ratio is 30% by volume or more and 55% by volume or less on the outermost surface on the protective glass side, and the packing is closest packed in a plane perpendicular to the depth direction of the sheet. There is a surface that is placed.

  In the solar cell module according to the second aspect, in the first aspect, the phosphor may be an inorganic compound phosphor.

  In the solar cell module according to the third aspect, in the second aspect, the average particle diameter of the inorganic compound phosphor may be not less than 0.03 μm and not more than 50 μm.

  In the solar cell module according to a fourth aspect, in any one of the first to third aspects, the resin may be polyethylene or an ethylene vinyl acetate copolymer.

  In the solar cell module according to the fifth aspect, in any one of the first to fourth aspects, in the second filler layer, a thickness of the distribution region of the phosphor is 0.06 μm or more and 400 μm or less. It may be.

  Hereinafter, solar cell modules according to embodiments will be described with reference to the accompanying drawings. In the drawings, substantially the same members are denoted by the same reference numerals.

(Embodiment 1)
FIG. 1 is a cross-sectional view of solar cell module 100 according to Embodiment 1. FIG. In solar cell module 100 according to Embodiment 1, at least photoelectric conversion element 101, first filler layer 102, back sheet 103, electrode 104, second filler layer 105, and protective glass 106 are provided. . In this solar cell module 100, a back sheet 103, a first filler layer 102, a photoelectric conversion element 101, a second filler layer 105, and a protective glass 106 are laminated in the order described above. It has a structure. The first filler layer 102 is formed of a transparent resin that protects the back surface of the photoelectric conversion element 101. The photoelectric conversion element 101 is electrically connected to the electrode 104. The second filler layer 105 is a sheet in which a plurality of particulate phosphors 108 are unevenly distributed on the protective glass 106 side in an ultraviolet absorber-containing resin 107. Specifically, the phosphor 108 is unevenly distributed on the protective glass 106 side of the ultraviolet absorber-containing resin 107, that is, on the light incident surface side, and the filling rate of the phosphor 108 on the outermost surface on the protective glass 106 side is 30. It has a configuration in which there is a surface that is arranged in a close-packed manner in the depth direction of the second filler layer 105 in the depth direction of the second filler layer 105.

  According to the configuration of the solar cell module 100, the phosphor 108 is unevenly distributed on the protective glass 106 side in the second filler layer 105 that is disposed closer to the light incident surface than the photoelectric conversion element 101 and contains an ultraviolet absorber. To form a phosphor unevenly distributed region. As a result, the proportion of the UV absorber present on the protective glass 106 side of the phosphor 108 is reduced, that is, the light emission due to UV absorption of the phosphor 108 is not easily inhibited. In addition, the adhesion between the protective glass 106 and the second filler layer 105 can be improved by controlling the filling rate of the phosphor 108 disposed on the outermost surface on the protective glass 106 side. Thereby, it is possible to obtain a solar cell module 100 in which high efficiency by wavelength conversion and adhesion between the protective glass 106 and the second filler layer 105 are ensured.

  Below, each structural member which comprises this solar cell module 100 is demonstrated.

<Photoelectric conversion element>
As the photoelectric conversion element 101, a silicon semiconductor such as a single crystal silicon, a polycrystalline silicon, or an amorphous silicon, or a compound semiconductor such as gallium arsenide or cadmium tellurium can be used. The photoelectric conversion element 101 may include a plurality of electrically connected photoelectric conversion elements 101. When a plurality of photoelectric conversion elements 101 are used, they may be connected directly or connected in parallel.

<Electrode>
The photoelectric conversion element 101 is electrically joined by the electrode 104. As the electrode 104, a known metal material or alloy metal can be used. The electrode 104 may include a pair of electrodes 104. An output from the photoelectric conversion element 101 can be obtained by the pair of electrodes 104. Further, when a plurality of photoelectric conversion elements 101 are connected to each other, they are connected to a pair of electrodes 104 so that an output can be obtained in each case of series or parallel.

<First filler layer>
As the first filler layer 102 on the back surface that protects the photoelectric conversion element 101, an ethylene vinyl acetate copolymer, a bisphenol epoxy resin cured product, polyethylene, an acrylic resin, a silicone resin, a polycarbonate resin, or the like may be used alone. it can. Moreover, these can also be used in mixture of 2 or more types.

<Back sheet>
The back sheet 103 is a protective member for preventing intrusion of water and foreign matter from the back surface of the solar cell module 100 to the inside, and for example, a polyethylene terephthalate film or the like can be used.

<Protective glass>
As the protective glass 106, a known plate-like glass having translucency and water shielding properties can be used.

<Ultraviolet absorber-containing resin>
The ultraviolet absorber-containing resin 107 is made of a transparent resin containing an ultraviolet absorber.
<Resin>
Examples of the resin include polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polystyrene styrene / acrylonitrile copolymer, styrene / butadiene / acrylonitrile copolymer, polyethylene, ethylene vinyl acetate copolymer, polypropylene, polymethyl methacrylate, methacryl styrene Copolymer, cellulose acetate, polycarbonate, polyester, PET, vinylidene trifluoride, epoxy resin, silicone resin, polyethersulfone, cycloolefin, triacetate, etc. can be used alone, and these can be used in combination of two or more. You can also The thickness can be 100 μm or more and 1000 μm or less. If the thickness is less than 100 μm, the ultraviolet rays that are not absorbed by the phosphor 108 cannot be sufficiently absorbed, and damage to the photoelectric conversion element 101 due to the ultraviolet rays cannot be suppressed. When the thickness is larger than 1000 μm, absorption of visible region light by the transparent resin itself increases, which causes a decrease in conversion efficiency by the photoelectric conversion element 101, which is not preferable. The ultraviolet absorber contained in the transparent resin is not limited in both composition and system, but those having an absorption wavelength peak of 300 nm or more and 400 nm or less can be used. When the peak of the absorption wavelength is smaller than 300 nm, the wavelength of ultraviolet rays that have not been absorbed by the phosphor 108 cannot be sufficiently absorbed, and damage to the photoelectric conversion element 101 due to the ultraviolet rays increases. If it is larger than 400 nm, it is difficult to protect the photoelectric conversion element 101 from ultraviolet rays by deviating from the wavelength region of the ultraviolet rays that have passed through the phosphor 108. Further, light in the long wavelength region emitted from the phosphor 108 is also absorbed, which hinders improvement in output due to conversion of the phosphor 108.

<Ultraviolet absorber>
As the ultraviolet absorber, it is preferable to use an organic ultraviolet absorber represented by a triazine compound, a benzotriazole compound, a benzophenone compound, or the like from the viewpoint of high transparency. An ultraviolet absorber may be used individually by 1 type, and may use 2 or more types together.

  Examples of triazine compounds include 2,4-bis (2-hydroxy-4-butoxyphenyl) -6- (2,4-dibutoxyphenyl) -1,3,5-triazine, 2- [2-hydroxy-4 -(1-Octyloxycarbonylethoxy) phenyl] -4,6-bis (4-phenylphenyl) -1,3,5-triazine and the like can be used.

  Examples of benzotriazole compounds include 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl). -1-phenylethyl) phenol, 2- (2-hydroxy-5-t-butylphenyl) -2H-benzotriazole, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (2H-benzotriazole) -2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2- (3,5-di-t-butyl-2 -Hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl- -Methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (5-di-t-octyl-2-hydroxyphenyl) benzotriazole, 2- [3- (2H-benzotriazol-2-yl) methacrylate ) -4-hydroxyphenyl] ethyl and the like.

  The benzophenone series includes 2,2′-dihydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophene, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy -4-n-octoxybenzophenone or the like can be used.

  The addition amount of the ultraviolet absorber may be determined so that the transmittance at an absorption wavelength of 300 nm to 400 nm is less than 5%. For example, in the case of a benzophenone-based ultraviolet absorber, the amount can be 0.05 parts by weight or more and 5 parts by weight or less with respect to the transparent resin of the ultraviolet absorber. If it is less than 0.05 parts by weight, the necessary thickness of the ultraviolet absorber-containing resin is greater than 1000 μm, which is not suitable. If it is greater than 5 parts by weight, the transmittance at an absorption wavelength of 300 nm to 400 nm is 5% or more. Therefore, it is inappropriate.

<Phosphor>
The phosphor 108 is a wavelength conversion material that absorbs light in a short wavelength region and emits fluorescence in a long wavelength region. The phosphor 108 is unevenly distributed in the vicinity of the surface of the ultraviolet absorber-containing resin 107 on the protective glass 106 side, thereby forming a phosphor unevenly distributed region. As this phosphor 108, from the viewpoint of reducing the loss due to reflection of incident light on the phosphor surface, the refractive index is close to that of the ultraviolet absorber-containing resin 107, and the inorganic compound fluorescence that does not dissolve. A body (hereinafter referred to as an inorganic phosphor) can be used. When the refractive indexes are different, it is preferable to select an inorganic phosphor having an average particle size of less than 100 nm with little light scattering in the visible wavelength region. In this embodiment, the average particle size of the phosphor 108 based calculated from the grain size distribution of number-based, and the value of D _50. In addition, the photoelectric conversion element 101 absorbs light in a short wavelength region with low sensitivity characteristics, emits light in a long wavelength region with high sensitivity characteristics as fluorescence, and absorbs ultraviolet light of 400 nm or less from the viewpoint of improving efficiency. It is preferable to emit fluorescence having a wavelength longer than 400 nm. When two types of phosphors are used, if a phosphor is selected so that the fluorescence wavelength emitted by the first phosphor and the absorption wavelength of the second phosphor overlap, fluorescence in a wider range of wavelengths can be obtained. It is preferable from the viewpoint of improving efficiency.

  As an inorganic fluorescent substance, it does not specifically limit and a well-known thing can be used. In general, an oxide, nitride, sulfide, or the like in which a metal element is activated as a luminescent ion can be used for a mother crystal. As the composition of the mother crystal, one or more elements such as B, Gd, O, S, Al, Ga, Ba, Sr, K, V, La, Cl, P, In, Zn, Y, Ca, Mg are used, Examples of the luminescent center element include inorganic phosphors in which one or more kinds of Zn, Ho, Tb, Nd, Ag, Mn, Ce, Eu, Dy, Tm, etc. are activated and used. In the present embodiment, when the inorganic phosphor as described above is used, the average particle size is preferably 0.03 μm or more and 0.3 μm or less. When it is smaller than 0.03 μm, the influence of the surface defect of the inorganic phosphor is increased, and the light emission efficiency is lowered. When it is larger than 0.3 μm, light having a wavelength with high sensitivity characteristics for the photoelectric conversion element 101 is lost due to scattering by the particles of the inorganic phosphor.

  Furthermore, examples of inorganic phosphors that can be suitably used include silica phosphors in which oxides, nitrides, sulfides, and the like containing elements that become luminescent ions are distributed in so-called silica fillers composed mainly of silicon dioxide. . Since the main component of silica phosphor is silica, that is, silicon dioxide, its refractive index is larger than 1.49 and smaller than 1.51. Therefore, when the filler resin that is the base of the ultraviolet absorber-containing resin 107 that is the second filler layer 105 is an ethylene vinyl acetate copolymer or polyethylene, it has a refractive index close to those, and transparency. Since it is easy to improve, it is preferable. When such a silica phosphor is used, the average particle diameter can be 0.05 μm or more and 50 μm or less. When the particle size is smaller than 0.05 μm, the phosphor particles are likely to aggregate. When the particle particles are aggregated, air is caught between the particles. When the particle size is larger than 50 μm, the light is scattered by the phosphor particles. Increases, transparency of the second filler layer 105 is impaired, and efficiency improvement is hindered.

<Second filler layer>
The second filler layer 105 is a sheet in which a plurality of particulate phosphors are unevenly distributed on the protective glass 106 side in the ultraviolet absorber-containing resin 107. Specifically, the phosphor 108 is unevenly distributed on the protective glass 106 side of the ultraviolet absorber-containing resin 107, that is, on the light incident surface side, and the filling rate of the phosphor 108 on the outermost surface on the protective glass 106 side is 30. It has a surface that is not less than 55% by volume and not more than 55% by volume and is arranged in a close-packed manner in a plane perpendicular to the depth direction of the second filler layer. It should be noted that the surface arranged in the closest packing may be a surface below the average particle diameter depth of the phosphor 108 from the outermost surface, that is, a surface immediately below the surface made of one particle. The details of the second filler layer 105 will be described below, which is an important part of the solar cell module 100 according to the present embodiment.

<Uniform structure of phosphor in ultraviolet absorber-containing resin>
The second filler layer 105 disposed closer to the light incident side than the photoelectric conversion element 101 of the solar cell module 100 according to the first embodiment has the phosphor 108 on the protective glass 106 side of the ultraviolet absorber-containing resin 107. The phosphor is unevenly distributed to form a phosphor unevenly distributed region. In the second filler layer 105, the thickness L of the region in which the phosphors 108 are unevenly distributed may be at least twice the average particle diameter of the phosphor particles and up to eight times the average particle diameter of the phosphor particles. it can. Therefore, the thickness L of the region where the phosphor 108 is unevenly distributed (phosphor unevenly distributed region) is 0.06 μm or more and 400 μm or less from the preferable range of the average particle diameter of the inorganic phosphor and the silica phosphor. Can do. When the phosphor 108 is unevenly distributed on the protective glass 106 side of the second filler layer 105 to form a phosphor unevenly distributed region by a method described later, up to eight embedding steps are appropriate in consideration of production costs. is there.

From the viewpoint of controlling the reflection and refraction of incident light by the phosphor 108, the difference between the refractive index of the phosphor 108 and the refractive index of the ultraviolet absorber-containing resin 107 is preferably small. Specifically, it is desirable that −0.005 ≦ n1−n2 ≦ 0.005, where n1 is the refractive index of the phosphor 108 and n2 is the refractive index of the ultraviolet absorber-containing resin 107.
The thickness L of the phosphor unevenly distributed region is included in the thickness d of the second filler layer 105 as shown in FIG.

(Method for manufacturing solar cell module)
A manufacturing process of solar cell module 100 in the first embodiment will be described.
(1) First, an ultraviolet absorber-containing resin 107 that is one of the constituent elements of the second filler layer 105 is produced. The ultraviolet absorber is dissolved or decomposed in advance by a known method such as mixing and kneading the ultraviolet absorber with the heat-dissolved transparent resin, and the ultraviolet absorber-containing resin 107 is formed into a sheet by roll stretching or hot pressing. . 1 g of a benzophenone-based UV absorber is added to 200 g of ethylene vinyl acetate copolymer and mixed for about 30 minutes at 100 rpm in a planetary mixer heated to 120 ° C. Further, the mixture is adjusted with a stainless spacer having a constant thickness by a hot press machine heated to 120 ° C., pressed and cooled to produce the ultraviolet absorbent-containing resin 107.

(2) FIG. 3A is a cross-sectional view showing a state in which the phosphor is embedded in the ultraviolet absorber-containing resin by closest packing in the method for manufacturing solar cell module 100 in the embodiment. FIG. 3B is a cross-sectional view illustrating a state in which the phosphor is arranged in the ultraviolet absorber-containing resin in the closest packing in the method for manufacturing solar cell module 100 in the embodiment.
Next, a particulate phosphor 108 is prepared, and is arranged unevenly on one surface of the ultraviolet absorber-containing resin 107 by the method described below, and is arranged in a state where the filling rate is adjusted. For example, the phosphors 108 are uniformly attached to the transfer sheet 303 using polyethylene terephthalate as the base material 301, and the phosphors 108 not attached to the adhesive layer 302 are blown using air so that there is no overlapping. The transfer sheet 303 to which the phosphor 108 is adhered is overlapped so that the phosphor 108 directly adheres to the ultraviolet absorber-containing resin 107 (FIG. 3A), and the transfer sheet 303 is hot-pressed while maintaining a certain gap with a spacer or the like. Is peeled off (FIG. 3B). The transfer sheet 303 is preferably a sheet in which the adhesive strength of the adhesive layer 302 is significantly reduced at a certain temperature or higher. Accordingly, the phosphor 108 attached to the transfer sheet 303 is embedded in the vicinity of the surface of the ultraviolet absorber-containing resin 107, and the transfer sheet 303 is peeled off in a heated state, so that the phosphor 108 does not remain in the adhesive layer 302. . Further, from the viewpoint of transferring and embedding the phosphor 108 in the ultraviolet absorber-containing resin 107 while heating, it is not necessary to be limited to the above hot press, and a hot roll method or the like can also be used.

(3) By repeating the uneven distribution process of attaching the phosphor 108 to the transfer sheet 303 in a non-overlapping state and embedding it while being transferred to the ultraviolet absorbent-containing resin 107 by hot pressing or the like, the ultraviolet absorbent is repeated 1-7 times. The phosphor 108 can be unevenly distributed on one surface of the containing resin 107 in a close-packed state in a plane perpendicular to the depth direction.

(4) FIG. 4A is a cross-sectional view showing a state in which the phosphor is embedded in the ultraviolet absorber-containing resin at a filling rate of 30% by volume to 55% by volume in the method for manufacturing solar cell module 100 in the embodiment. FIG. 4B is a cross-sectional view showing a state where the phosphor is arranged in the ultraviolet absorber-containing resin at a filling rate of 30% by volume to 55% by volume in the method for manufacturing solar cell module 100 in the embodiment.
Further, when embedded, the filling rate of the phosphor 108 existing on the outermost surface is in the range of the depth of the average particle diameter of the phosphor 108 from the surface of the ultraviolet absorber-containing resin 107 to 30 volume% or more and 55 volume% or less. Then, a mask 401 is stacked on the adhesive layer 302 side of the transfer sheet 303, and the phosphor 108 is attached to the adhesive layer 302. Thereafter, by embedding while being transferred to the ultraviolet absorber-containing resin 107 in the same manner as described above, the filling ratio of the phosphor 108 on the outermost surface is 30% by volume to 55% by volume, and the second filler A second filler layer 105 can be formed having a face that is arranged in a close-packed manner in a plane perpendicular to the depth direction of the layer 105. It should be noted that the surface arranged in the closest packing may be a surface below the average particle diameter depth of the phosphor 108 from the outermost surface, that is, a surface immediately below the surface made of one particle.

Examples and comparative examples will be specifically described below.
Tables 1 and 2 below show the blending of the phosphor 108 and the ultraviolet absorber-containing resin 107 in each example, the blending in the comparative example, and the evaluation results described later.

(Example 1)
Example 1 is a solar cell for evaluation using a silica phosphor formed by embedding and sintering phosphor fine particles having Eu ²⁺ as an emission center in a porous portion of a porous silica filler as a phosphor. This is an example of producing a module.
(1) The average particle diameter of the silica phosphor is 10 μm. As the UV absorber, 1 g of 2,4-dihydroxybenzophenone, which is a benzophenone UV absorber, is added to 200 g of low density polyethylene and mixed for about 30 minutes at 100 rpm in a planetary mixer heated to 150 ° C. With a hot press machine heated to 150 ° C., the gap was adjusted with a 550 μm stainless steel spacer, pressed, and cooled to obtain an ultraviolet absorber-containing resin.
(2) Further, a silica phosphor was attached to the adhesive layer side of the transfer sheet in an amount of 500 μg per cm ^{2, and the} side of the transfer sheet on which the phosphor was attached was overlaid on one side of the resin containing the ultraviolet absorber. Next, adjust the gap with a 550 μm stainless steel spacer with a hot press heated to 150 ° C., peel off the transfer sheet in a pressed and heated state, and cool the silica phosphor adhering to the transfer sheet to contain an ultraviolet absorber. It was embedded near the surface of the resin. Further, when embedded by the above method, the filling rate of the silica phosphor existing on the outermost surface is 55% by volume in the range of the average particle diameter of the silica phosphor from the surface of the ultraviolet absorber-containing resin. A simple mask is placed on the adhesive layer side of the transfer sheet, and the phosphor is attached to the adhesive layer side. Thereafter, the silica phosphor adhering to the transfer sheet by the same method as described above was embedded in the ultraviolet absorber-containing resin, and the uneven distribution process was repeated twice to obtain the second filler layer in this example.
(3) In addition, the protective glass, the second filler layer in which the phosphor unevenly distributed region is arranged on the protective glass side, the photoelectric conversion elements connected to each other by electrodes, the first filler layer, and the back sheet are laminated in order. As a result, an evaluation module was created.

(Examples 2 to 5)
Example 2 is the same as Example 1 except that the number of uneven distribution processes is 8, the thickness of the uneven distribution region of the phosphor is 80 μm, and the phosphor filling ratio of the outermost surface is 30% by volume. is there.
In Example 3, the average particle diameter of the silica phosphor is 1.0 μm, the thickness of the unevenly distributed region of the phosphor is 2.0 μm, and the ultraviolet absorber is 2,5-dihydroxybenzophenone, The same as in the first embodiment.
In Example 4, the average particle diameter of the silica phosphor is 50 μm, the number of uneven distribution processes is 8, the thickness of the uneven distribution region of the phosphor is 400 μm, and the ultraviolet absorber is 2,6-dihydroxybenzophenone. Except for this point, the second embodiment is the same as the first embodiment.
In Example 5, the phosphor is an inorganic phosphor, and among the inorganic phosphors, ZnSiO ₄ : Mn (hereinafter referred to as manganese-containing zinc silicate) having an average particle size of 0.03 μm is used. It is the same as Example 1 except that the thickness is 0.06 μm and the resin in the ultraviolet absorber-containing resin is an ethylene vinyl acetate copolymer.

(Comparative Example 1)
In Comparative Example 1, the phosphor is not unevenly distributed in the ultraviolet absorber-containing resin, but a sheet in which the phosphor is dispersed (hereinafter referred to as a phosphor dispersion sheet) is produced, and the back sheet and the first filling are prepared. The module for evaluation was produced by laminating | stacking in order of the photoelectric conversion element mutually connected by the material layer, the electrode, the fluorescent substance dispersion sheet, and the protective glass. The phosphor dispersion sheet was produced by the method described below. An ultraviolet absorber-containing resin was produced in the same manner as in Example 1. Thereafter, the phosphor was blended with the ultraviolet absorber-containing resin and kneaded at 100 rpm for about 30 minutes in a planetary mixer heated to 150 ° C. The kneaded product was adjusted to a gap with a 550 μm stainless steel spacer with a hot press machine heated to 150 ° C., pressed and cooled to prepare a phosphor dispersion sheet.

(Comparative Examples 2 to 5)
Comparative Example 2 is the same as Example 1 except that the filling ratio of the outermost surface phosphor is 70% by volume.
Comparative Example 3 is the same as Example 1 except that the number of uneven distribution processes is one and the thickness of the uneven distribution region of the phosphor is 10 μm.

(Phosphor uneven distribution thickness)
The phosphor unevenly distributed region thickness was measured by observing the cross section of the second filler layer with a scanning electron microscope (SEM).

(Adhesion)
Based on JISK6854-1: 1991, a peel adhesion strength test piece was prepared from the second filler layer, and the adhesion was measured by a peel adhesion strength test.
Judgment criteria 10N or more as an excellent range of evaluation adhesion ...
Less than 10N as the range with poor adhesion
When the adhesion is 10 N or more, the reliability of the solar cell module can be ensured. Therefore, the adhesion is in an excellent range, and less than 10 N is in the inferior range.

(Relative output value)
About each produced solar cell module evaluation module, the output at the time of Xe lamp light irradiation by solar simulation was calculated | required, and when the comparative example 1 was set to 1, the relative value (difference) was calculated | required.
Judgment criteria 0.5 or more as an excellent range of evaluation output value improvement
Less than 0.5 as the range where output value improvement is inferior
When the relative output value is 0.5 or more, the solar cell module can be put into practical use as a product, so that the output value improvement is in an excellent range, and less than 0.5 is the inferior output value improvement range.

(Comprehensive judgment)
In the determination of the adhesion force and the determination of the output value in each example and comparative example, the case where there was at least one X was indicated as X, and the other cases were indicated as ◯.

From the results shown in Tables 1 and 2, the following can be understood.
By comparing Example 1 with Comparative Example 1 and Comparative Example 2, it can be seen that the solar cell module according to the configuration of the present invention is a solar cell module that achieves both improved conversion efficiency and secure adhesion.
From comparison between Examples 1 and 2 and Comparative Example 2, it can be seen that high adhesion can be obtained when the filling ratio of the outermost surface phosphor is 30% or more and 55% or less.
By comparing Examples 1, 2, 4 and Comparative Example 3, it can be seen that a high output can be obtained when the thickness of the unevenly distributed region of the phosphor is 0.06 μm or more and 400 μm or less.

  It should be noted that the present disclosure includes appropriately combining any of the various embodiments and / or examples described above, and each of the embodiments and / or examples. The effect which an Example has can be show | played.

  As described above, the solar cell module according to the present invention converts the light in the ultraviolet region where the photoelectric conversion element cannot be effectively used into the light that can be effectively used by the phosphor, thereby converting the light into a photoelectric conversion element using ultraviolet light. The damage is suppressed. Moreover, the adhesiveness of a protective glass and a 2nd filler layer is ensured by adjusting the filling rate of fluorescent substance. Thereby, the photoelectric conversion efficiency of the solar cell module can be improved and the lifetime can be extended.

DESCRIPTION OF SYMBOLS 100 Solar cell module 101 Photoelectric conversion element 102 1st filler layer 103 Back sheet 104 Electrode 105 2nd filler layer 106 Protective glass 107 Ultraviolet absorber containing resin 108 Phosphor 301 Base material 302 Adhesive layer 303 Transfer sheet 401 Mask

Claims (5)

A backsheet,
A first filler layer;
An electrode and a photoelectric conversion element connected to the electrode;
A second filler layer;
Protective glass,
Is a solar cell module having a structure laminated in the above order,
The second filler layer is a sheet in which a plurality of particulate phosphors are unevenly distributed on the protective glass side in the ultraviolet absorber-containing resin,
As for the distribution of the phosphor in the sheet, the packing ratio is 30% by volume or more and 55% by volume or less on the outermost surface on the protective glass side, and the packing is closest packed in a plane perpendicular to the depth direction of the sheet. A solar cell module with a surface on which it is placed.   The solar cell module according to claim 1, wherein the phosphor is an inorganic compound phosphor.   The solar cell module according to claim 2, wherein the inorganic compound phosphor has an average particle size of 0.03 μm or more and 50 μm or less.   The solar cell module according to any one of claims 1 to 3, wherein the resin is polyethylene or ethylene-vinyl acetate copolymer.   5. The solar cell module according to claim 1, wherein, in the second filler layer, a thickness of a distribution region of the phosphor is 0.06 μm or more and 400 μm or less.