Pavement photovoltaic module and cover glass

Abstract

A pavement photovoltaic module (100) includes a cover glass (200), a photovoltaic cell (330), and a sealing layer (300) that seals the photovoltaic cell (330), wherein: the cover glass (200) is disposed on a light receiving surface side of the photovoltaic cell (330); the cover glass (200) has a first side and a second side; the photovoltaic cell (330) is disposed on the second side; the cover glass (200) includes a particle layer (210) and a glass substrate (220); the particle layer (210) is disposed on the first side; the glass substrate (220) is disposed on the second side; the particle layer (210) includes particles A protruding from a surface thereof and a binder (211); the binder (211) is a fired product of glass frit; the particle size of the particles A is 0.05 to 1 mm; the particles A are bonded to the glass substrate (220) by means of the binder (211); and the volume ratio VA of the particles A in the entire particle layer (210) is 15 to 60%.

Description

Photovoltaic modules and cover glass for paving

[0001] The present invention relates to a photovoltaic paving module and cover glass.

[0002] Solar power generation is a power generation method that utilizes the phenomenon of electricity being generated when light hits various materials, typically silicon semiconductors, and directly converts the energy of sunlight into electricity using solar cells, i.e., semiconductor elements. Solar power generation is a form of power generation that uses renewable energy, and has become increasingly important because it does not emit or increase greenhouse gases. In addition, governments around the world have implemented policies to introduce solar power generation, and large-scale solar power generation facilities are being put into operation, increasing total power generation and demonstrating the ability to withstand long-term operation.

[0003] Therefore, in order to avoid environmental destruction and ensure sufficient installation area, it has been proposed to place photovoltaic modules on the road surface. For example, Patent Document 1 describes a road tile having a cavity formed therein and a solar cell held inside by an elastic body. Also, Patent Document 2 describes a photovoltaic module in which a photovoltaic module is attached to one surface of a translucent support member made of polycarbonate or the like, and a surface coating layer made of a resin containing fine particles is provided on the other surface.

[0004] On the other hand, Patent Document 3 describes a flat substrate on which a glass coating layer is formed by heating a coating film containing glass frit and particles having a size of 0.5 to 40 μm. Because the softening temperature or melting temperature of these particles is higher than the softening temperature of the glass component, convex portions due to these particles are formed on the surface of the glass coating layer.

[0005] Japanese Patent Publication No. 2002-118279 Japanese Patent No. 6814445 U.S. Patent No. 10,611,677

[0006] However, the technology disclosed in Patent Document 1 has problems such as limitations on improving load-bearing performance and difficulty in increasing the surface area because a cavity is provided inside the road tiles. Furthermore, the technology disclosed in Patent Document 1 does not take into consideration factors such as slip resistance when vehicles and pedestrians pass on the road, making it difficult to ensure good power generation performance and driving performance in an actual usage environment.

[0007] Furthermore, in the technology disclosed in Patent Document 2, the photovoltaic module having a surface coating layer made of a resin containing fine particles has problems with durability when laid on a vehicle or pedestrian road.

[0008] On the other hand, the technology disclosed in Patent Document 3 is intended for application to, for example, doors, kitchen furniture, etc. as light-transmitting panels for architectural interior materials, and satisfies the requirements for a coating layer in a home environment, such as abrasion resistance, scratch resistance, thermal stability, and chemical resistance. However, when applied in an outdoor environment, particularly as a road pavement, there are problems with slip resistance and abrasion resistance when vehicles and pedestrians pass on the road.

[0009] The present invention has been made in consideration of the above problems, and aims to provide a photovoltaic module for paving and a cover glass that can ensure good slip resistance and abrasion resistance even in actual use environments.

[0010] A photovoltaic module for paving according to one aspect of the present disclosure has the following configuration.

[0011] [1] A photovoltaic module for paving, comprising: a cover glass; a photovoltaic cell; and a sealing layer that seals the photovoltaic cell; wherein the cover glass is disposed on a light receiving surface side of the photovoltaic cell; the cover glass has a first side and a second side, and the photovoltaic cell is disposed on the second side; the cover glass comprises a particle layer and a glass substrate, the particle layer is disposed on the first side, and the glass substrate is disposed on the second side; the particle layer comprises particles A protruding from a surface and a binder; the binder is a fired product of glass frit; the particle A has a particle size of 0.05 mm or more and 1 mm or less; the particles A are bonded to the glass substrate using the binder; and the volume ratio V of the particles A in the entire particle layer is Ａ A photovoltaic module for paving, wherein the ratio of the surface area to the surface area of ​​the photovoltaic module is 15% or more and 60% or less.

[0012] [2] The photovoltaic module for paving according to [1], wherein the particle layer contains particles B, and the particle diameter of the particles B is 0.1 μm or more and 10 μm or less.

[0013] [3] The photovoltaic module for paving according to [2], wherein the particles B are crystalline particles, and the Mohs hardness of the particles B is 6.5 or more.

[0014] [4] The volume ratio of the particles B and the binder in the particle layer is V Ｂ , V Ｆ Then, V Ｂ / (V Ｆ +V Ｂ ) is 0.4 or less. [2] The photovoltaic module for paving according to [3] or [4].

[0015] [5] The photovoltaic module for paving according to any one of [1] to [4], wherein the particle layer has air bubbles.

[0016] [6] The number of bubbles contained in the particle layer is 100 / mm ３ The photovoltaic module for paving described in [5] above.

[0017] [7] The photovoltaic module for paving described in any one of [1] to [6], wherein the particle layer is patterned into a predetermined shape when viewed from above.

[0018] [8] The photovoltaic module for paving according to any one of [1] to [7], wherein the composition of the glass substrate and the composition of the binder are different.

[0019] [9] The photovoltaic module for paving according to any one of [1] to [8], wherein the strain point of the glass substrate is 30° C. or more higher than the softening point of the binder.

[0020]

[10] A photovoltaic module for paving described in any one of [1] to [9], having the relationship of thermal expansion coefficient of the glass substrate ≧ thermal expansion coefficient of the binder ≧ thermal expansion coefficient of the particles.

[0021]

[11] The photovoltaic module for paving described in any one of [2] to

[10] , wherein the material of the particles B is one or more selected from the group consisting of alumina, zirconia, silica, and zircon.

[0022]

[12] The photovoltaic module for paving according to any one of [1] to

[11] , wherein the particle layer contains a pigment made of an inorganic material.

[0023]

[13] The photovoltaic module for paving according to

[12] , wherein the pigment material is a metal oxide.

[0024]

[14] The photovoltaic module for paving according to

[12] or

[13] , wherein the concentration of the pigment in the particle layer is 5 vol% or less.

[0025] A cover glass according to one aspect of the present disclosure has the following configuration.

[0026]

[15] A cover glass to be placed on a light-receiving surface side of a photovoltaic cell, the cover glass having a first side and a second side, the photovoltaic cell being placed on the second side, the cover glass including a particle layer and a glass substrate, the particle layer being placed on the first side and the glass substrate being placed on the second side, the particle layer including particles A protruding from a surface thereof and a binder, the binder being a fired product of glass frit, the particle A having a particle size of 0.05 mm or more and 1 mm or less, the particles A being bonded to the glass substrate using the binder, and a volume ratio V of the particles A in the entire particle layer Ａ A cover glass having a refractive index of 15% or more and 60% or less.

[0027]

[16] The cover glass according to

[15] , wherein the particle layer contains particles B, and the particle diameter of the particles B is 0.1 μm or more and 10 μm or less.

[0028] According to the present invention, it is possible to provide a photovoltaic module for paving and a cover glass that can ensure good slip resistance and abrasion resistance even in an actual use environment.

[0029] 1 is a schematic perspective view showing an example of the structure of a paving photovoltaic module according to embodiment 1. FIG. 2 is a schematic cross-sectional view showing an example of the structure of a cover glass provided in the paving photovoltaic module according to embodiment 1. FIG. 3 is a schematic cross-sectional view showing an example of the structure of a photovoltaic cell-containing sealing layer provided in the paving photovoltaic module according to embodiment 1. FIG. 4 is a front view showing an example of pattern coating. FIG. 5 is a front view showing another example of pattern coating. FIG. 6 is a schematic cross-sectional view showing an example of the structure of a cover glass provided in a paving photovoltaic module according to embodiment 2. FIG. 7 is a graph showing the relationship between the particle size of particle A and the skid resistance. FIG. 8 is a graph showing the relationship between the volume ratio of particle A and the wear amount. FIG. 9 is a graph showing the relationship between the volume ratio of particle A and the skid resistance. FIG. 10 is a photograph of the surface of a cover glass when a predetermined amount of particle A is added at a volume ratio. FIG. 11 is a graph showing the relationship between the addition rate of particle B and the wear amount. FIG. 12 is a photograph showing the results of a Taber test performed on a cover glass to which a predetermined amount of particle B is added at a volume ratio. FIG. 13 is a photograph of the surface of a cover glass when a predetermined amount of particle B is added at a volume ratio. FIG. 14 is a graph showing the reflectance of a cover glass when a pigment is added.

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are designated by the same reference numerals, and duplicate explanations will be omitted as necessary for clarity. In addition, "to" means a value equal to or greater than the value before "to" and equal to or less than the value after "to".

[0031] <Embodiment 1> FIG. 1 is a schematic perspective view showing an example of the structure of a paving photovoltaic module 100 according to Embodiment 1. The paving photovoltaic module 100 includes at least a cover glass 200 and a photovoltaic cell-containing sealing layer 300, and may further include a back glass 400. The photovoltaic cell-containing sealing layer 300 includes photovoltaic cells and a sealing layer that seals the photovoltaic cells. The paving photovoltaic module 100 is installed, for example, on a roadway or a sidewalk and receives sunlight. The top surface of the paving photovoltaic module 100 shown in FIG. 1, i.e., the surface on which the cover glass 200 is disposed, is the light-receiving surface. That is, the cover glass 200 is disposed on the light-receiving surface side of the photovoltaic cell-containing sealing layer 300. The light-receiving surface side of the cover glass 200, i.e., the side not in contact with the photovoltaic cell-containing sealing layer 300, is referred to as the first side 200a. The side of the cover glass 200 that is in contact with the photovoltaic cell-containing sealing layer 300 is referred to as the second side 200b. The back glass 400 is disposed on the side of the photovoltaic cell-containing sealing layer 300 that is not in contact with the cover glass 200.

[0032] [Cover Glass] Fig. 2 is a schematic cross-sectional view showing an example structure of the cover glass 200. The cover glass 200 includes a particle layer 210 and a glass substrate 220. As shown in Fig. 2, the particle layer 210 is disposed on a first side 200a of the cover glass 200. The glass substrate 220 is disposed on a second side 200b of the cover glass 200. The particle layer 210 includes particles 212 and a binder 211. The particle layer 210 includes particles 212 protruding from the surface of the first side 200a. The particles 212 are particles A, which will be described later.

[0033] 2, the particle layer 210 includes a binder 211 and particles 212. The binder 211 is a fired product of glass frit. The particles 212 are bonded to the glass substrate 220 using the binder 211.

[0034] The particle layer 210 may have bubbles. The size of the bubbles in the particle layer 210 is preferably equal to or smaller than the thickness of the particle layer 210.

[0035] The number of bubbles contained in the particle layer 210 is preferably 100 / mm ３ More preferably, 1×10 ３ pieces / mm ３ or more, and more preferably 1×10 ４ pieces / mm ３ or more, and most preferably 1×10 ５ pieces / mm ３ The number of bubbles contained in the particle layer 210 is preferably 1×10 １０ pieces / mm ３ The following is the result.

[0036] The thickness of the particle layer 210 may be, for example, 0.02 mm or more, 0.03 mm or more, 0.04 mm or more, 0.05 mm or more, 0.06 mm or more, 5 mm or less, 4 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less. The thickness of the particle layer 210 is measured as follows. First, if the particle layer 210 is patterned, a stylus-type film thickness meter is used to measure the cross-sectional curve of the surface of the first side 200 a of the cover glass, including both areas with and without the particle layer 210. Because the surface of the particle layer 210 is uneven due to the protrusion of the particles 212, the average height of the unevenness is calculated, and the difference between this height and the height of the area without the particle layer is determined and used as the layer thickness. In addition, when the particle layer 210 is solidly coated, the cover glass 200 is cut and the cross section is polished, and an image of the cross section is taken using an optical microscope or the like. A line is drawn on the image to average out the irregularities on the surface of the particle layer 210, and the distance between this line and the surface of the glass substrate 220 that is in contact with the particle layer 220 is determined, and this is taken as the layer thickness.

[0037] The thickness of the binder 211 in the peripheral portion of the particle 212 is preferably thicker than that in the portion away from the particle 212. That is, the binder 211 preferably forms a bulge around the particle 212.

[0038] The particle layer 210 may be provided over the entire surface of the first side 200a of the cover glass 200, i.e., solidly coated, or may be patterned into a predetermined shape when viewed from the front, i.e., patterned. Here, the predetermined shape is not particularly limited and may be, for example, a circle, an ellipse, a polygon, or the like. FIGS. 4 and 5 are front views showing an example of a patterned particle layer 210. The particle layer 210 may be patterned in a dot shape as shown in FIG. 4. Alternatively, the particle layer 210 may be patterned in a checkered steel plate shape as shown in FIG. 5.

[0039] <<Particles A>> Particles 212 are particles A. Particles A may be crystalline particles, glass particles, ceramic particles, or the like. From the viewpoint of the required slip resistance and durability of the road surface, particles A are preferably crystalline particles. Examples of crystalline particles include SiO ２ , Al ２ O ３ , ZrO ２ , and ZrSiO ４ Furthermore, from the viewpoint of power generation efficiency, transparent particles without coloring are preferred, and white alumina, SiO ２ etc. is good.

[0040] Furthermore, the particles A may be glass particles from the viewpoint of affinity with the binder 211 and the glass substrate 220. When the particles A are glass particles, the glass constituting the particles A is referred to as a third glass. Furthermore, the glass constituting the binder 211 is referred to as a second glass. The composition of the glass particles, i.e., the third glass, is preferably different from the composition of the glass frit, i.e., the second glass. The strain point of the third glass is more preferably 30° C. or more higher than the softening point of the second glass.

[0041] The particle size of particles A is 0.05 to 1 mm. The lower limit of the particle size of particles A is preferably 0.06 mm, more preferably 0.07 mm, and even more preferably 0.08 mm. When the particle size of particles A is 0.05 mm or more, the necessary slip resistance value for a road surface is obtained. Furthermore, the upper limit of the particle size of particles A is preferably 0.6 mm, more preferably 0.4 mm, and even more preferably 0.2 mm. When the particle size of particles A is 1 mm or less, the particles A are prevented from falling off the cover glass 200, and sufficient durability is obtained. Furthermore, when the particle size of particles A is 1 mm or less, roughness on the surface of the cover glass 200 is suppressed, ensuring safety in the event of a person traveling on the road falling.

[0042] The particle size of particle A is the equivalent circle diameter, which is calculated by measuring the area of ​​the particle in a planar view using a surface image of the cover glass obtained using an optical microscope or the like, and calculating the diameter of a circle with the same area. If the boundary between particle A and binder 211 is difficult to discern using this method, the cover glass 200 can be cut and polished as necessary, and a cross-sectional image of the particle layer 210 taken using an optical microscope or the like can be used to measure the area of ​​the particle in a planar view, and the diameter of a circle with the same area is calculated as the particle size. Because both measurement methods involve a certain degree of variability, particle size calculations are performed for at least 50 particles. Furthermore, "particles with a particle size of 0.05 to 1 mm" means that the number of particles with a particle size of 0.05 to 1 mm is 50% or more, preferably 60% or more, and more preferably 65% ​​or more of the total number of particles.

[0043] The shape of the particles A is not particularly limited, and may be polygonal, plate-like, rod-like, irregular, etc. From the viewpoint of obtaining the required slip resistance value, the shape of the particles A is preferably irregular with sharp corners rather than a smooth shape such as a sphere. For example, the particles A may be SiO ２ , Al ２ O ３ , or ZrO ２ For example, the particles A may be irregularly shaped particles obtained by crushing crystals of a metal oxide such as fluorine, fluorine, methyl methacrylate ...

[0044] At least some of the particles A protrude from the surface of the first side 200a of the cover glass 200. At least some of the other particles A may be completely buried in the binder 211. In the present invention, "the cover glass includes particles protruding from the surface on the first side" includes an embodiment in which the surfaces of the protruding particles are coated. In other words, "particles protruding from the surface" refers to particles protruding from an area of ​​the surface of the first side where no particles are provided, and the surfaces of the particles may be coated with the binder 211 or may be exposed to the outside without being coated with the binder 211.

[0045] The volume ratio V of particles A in the entire particle layer 210 Ａ The volume ratio V is 15% or more and 60% or less. Ａ The lower limit of the volume ratio V is preferably 18%, more preferably 20%, and even more preferably 25%. Ａ When the volume ratio V is 15% or more, the necessary skid resistance and abrasion resistance for the road surface can be obtained. Ａ The upper limit of the volume ratio V is preferably 50%. Ａ When the surface roughness is 60% or less, the occurrence of holes in the surface of the cover glass 200 can be suppressed, and dust and the like are less likely to accumulate in the holes.

[0046] Volume ratio V Ａ is calculated by calculating the sum of the areas of all particles in the field of view in the image obtained when measuring the particle size of particle A, and dividing this sum by the total field of view area. Using five images, the average value calculated for each image is taken as the volume ratio V Ａ Let's say.

[0047] <<Binder>> The binder 211 is a fired product of glass frit, and is a layer formed by firing a coating layer containing glass frit.

[0048] The composition of the glass frit, i.e., the second glass, is preferably different from the composition of the glass substrate 220, i.e., the first glass, which will be described later. The strain point of the first glass is preferably higher than the softening point of the second glass by at least 20° C., more preferably by at least 30° C., and even more preferably by at least 50° C. Examples of glasses that constitute the glass frit include soda-lime silicate glass, borosilicate glass, alkali-free glass, and quartz glass.

[0049] The binder 211 may have air bubbles. If the binder 211 has air bubbles, sunlight may be scattered within the binder 211, increasing the amount of light that reaches the photovoltaic cell. The size of the air bubbles is preferably equal to or smaller than the film thickness of the binder 211.

[0050] The number of bubbles contained in the binder 211 is 100 / mm ３ The above is preferable. The number of bubbles was counted as follows. First, the binder 211 was polished until its thickness was about 15 μm. This is because, with this thickness, all bubbles present in the thickness direction can be confirmed when observed with an optical microscope. Next, optical microscope observation was performed, and bubbles with a diameter of 0.5 μm or more within the field of view were identified and counted by image processing. The number of bubbles thus obtained was divided by the thickness of the binder 211 and the field of view area to obtain the number of bubbles mm ３ Since the number of bubbles varied depending on the location, measurements were taken at three random locations and the average value was calculated.

[0051] <<Other Materials>> The particle layer 210 may contain other materials. Examples of other materials include pigments. From the viewpoint of weather resistance, the pigment is preferably made of an inorganic material. Examples of inorganic materials include metal oxides such as oxides of chromium, cobalt, copper, nickel, manganese, and iron. The concentration of the pigment in the particle layer 210 is 5 vol% or less from the viewpoint of ensuring sufficient power generation efficiency.

[0052] <Glass Substrate> The glass substrate 220 may be a glass plate. Specific examples of materials constituting the glass plate include soda lime silicate glass, quartz glass, crystal glass, alkali-free glass, aluminosilicate glass, borosilicate glass, and barium borosilicate glass. Soda lime silicate glass with a reduced iron content is preferred as the glass substrate 220 because of its high transparency.

[0053] Specific examples of soda lime silicate glass include glass containing 60 to 75 mass % SiO on an oxide basis. ２ , 0 to 3 mass % Al ２ O ３ , 0 to 15 mass% CaO, 0 to 12 mass% MgO, and 5 to 20 mass% Na ２ Examples of the glass include glasses having a composition of SiO. ２ is the main component of soda lime silicate glass. In addition to the above materials, soda lime silicate glass also contains K ２ O, TiO ２ , ZrO ２ , SrO, BaO and LiO ２ The soda lime silicate glass may further include at least one material selected from the group consisting of: In addition, the soda lime silicate glass may further include a fining agent, such as SO3, SnO2, or Sb2O3.

[0054] The glass substrate 220 may be laminated glass. Laminated glass has an integrated structure formed by bonding a pair of glass plates together with an interlayer film such as a resin interposed therebetween. The laminated glass is not particularly limited, and known laminated glass may be used. The thickness and number of layers of the glass plates included in the laminated glass, and the material and thickness of the interlayer film included in the laminated glass, are not particularly limited, and may be similar to those of known laminated glass.

[0055] For example, tempered glass that has been subjected to a tempering treatment is used as the glass substrate 220. The glass substrate 220 made of tempered glass is less likely to break than a glass substrate that has not been tempered. For example, a glass plate having a surface layer with residual compressive stress, a back surface layer with residual compressive stress, and an intermediate layer formed between the surface layer and the back surface layer and with residual tensile stress is used as the tempered glass plate.

[0056] Specific examples of tempering treatments include chemical tempering treatments performed by known ion exchange methods, etc., and physical tempering treatments performed by known air-cooling tempering methods, etc. Chemically tempered glass sheets can increase the residual compressive stress value of the front or back layer even when the sheet thickness is thin, and have sufficient strength. On the other hand, when the sheet thickness is thick, about 3 mm or more, physical tempering treatments are effective.

[0057] A glass plate that has not been tempered may be used as the glass substrate 220. For example, if the glass substrate 220 is not tempered, the occurrence of spider web-like cracks when the glass substrate 220 is broken is suppressed. Therefore, even if the glass substrate 220 is broken, the increase in light scattering is suppressed. Therefore, the decrease in light reaching the cell due to the increase in light scattering is suppressed, and the decrease in power generation efficiency is suppressed. Furthermore, if laminated glass is used as the glass substrate 220, scattering of fragments can be suppressed.

[0058] The glass substrate 220 may be surface-treated in terms of adhesion with the photovoltaic cell-containing sealing layer 300 described below. Known methods can be used for the surface treatment, including activation treatment (plasma method, vapor deposition method, acid treatment, base treatment, etc.), chemical conversion treatment, polishing of the material surface, sanding, sealing treatment, blasting, and primer treatment. Specific examples of primer agents include silane coupling agents (particularly, alkoxysilanes, etc.), epoxy resins, (meth)acrylic resins, and polyester resins.

[0059] The glass substrate 220 is made of Fe, expressed as a mass percentage based on oxides. ２ O ３The concentration of Fe is preferably less than 1000 ppm, more preferably less than 500 ppm, and even more preferably less than 100 ppm. ２ O ３ When the content of is within the above range, Fe ２ O ３ Since the absorption of near-infrared light by Fe can be suppressed, the transmittance in the near-infrared region is high and the power generation efficiency is improved. ２ O ３ The glass substrate 220 having a content of less than 1000 ppm is suitable for the photovoltaic cell-containing sealing layer 300 having a photovoltaic cell with high spectral sensitivity to near-infrared light. ２ O ３ The content of Fe is the total iron content contained in the glass substrate 220. ２ O ３ The content is calculated by X-ray fluorescence measurement.

[0060] The thickness of the glass substrate 220 can be set arbitrarily depending on the type of road to be laid, etc. The thickness of the glass substrate 220 is preferably 1 to 70 mm. The lower limit of the thickness of the glass substrate 220 is more preferably 3 mm, even more preferably 6 mm, and particularly preferably 8 mm. If the thickness of the glass substrate 220 is within the above range, the glass substrate 220 is highly durable and less likely to break. If the thickness of the glass substrate 220 is 70 mm or less, the glass substrate 220 becomes lightweight, making it easier to install the paving photovoltaic module 100 of this embodiment. The thickness of the glass substrate 220 is the arithmetic mean value of the thickness obtained by measuring the cover glass using a thickness meter.

[0061] The relationship between the thermal expansion coefficient of glass substrate 220, binder 211, and particles A is preferably expressed by the following formula: Thermal expansion coefficient of glass substrate ≧ Thermal expansion coefficient of binder ≧ Thermal expansion coefficient of particles A When the thermal expansion coefficient of glass substrate 220 satisfies the above relationship, particles A are firmly fixed to the surface of cover glass 200, even after firing and cooling in the manufacturing process of cover glass 200 described below, and sufficient durability is obtained.

[0062] 3 is a schematic cross-sectional view showing one embodiment of a photovoltaic cell-containing sealing layer 300. The photovoltaic cell-containing sealing layer 300 includes a photovoltaic cell 330 and a sealing layer 310 that seals the photovoltaic cell 330. The sealing layer 310 includes a first sealing material 320 and a second sealing material 340. For example, the photovoltaic cell-containing sealing layer 300 includes, in this order from the light-receiving surface side of the photovoltaic cell-containing sealing layer 300, the first sealing material 320, a plurality of photovoltaic cells 330, and the second sealing material 340.

[0063] The first sealing material 320 contains a resin. The resin contained in the first sealing material 320 is preferably at least one resin selected from the group consisting of an olefin resin such as an ethylene-vinyl acetate copolymer (EVA resin), a polyvinyl butyral resin (PVB resin), an ionomer resin, and a silicone resin. In terms of adhesion to the cover glass 200, the resin contained in the first sealing material 320 is particularly preferably at least one resin selected from the group consisting of an ethylene-vinyl acetate copolymer and a polyvinyl butyral resin.

[0064] The first sealing material 320 is preferably transparent. When the first sealing material 320 is transparent, light that has passed through the cover glass 200 can easily reach the first light receiving surface 331 of the photovoltaic cell 330.

[0065] The thickness of the first sealing material 320 is preferably 50 to 2,000 μm, more preferably 70 to 1,500 μm, even more preferably 100 to 1,200 μm, and particularly preferably 150 to 1,000 μm. When the thickness of the first sealing material 320 is 50 μm or more, the ultraviolet absorption efficiency and durability are excellent. When the thickness of the first sealing material 320 is 2,000 μm or less, the economy is excellent and deformation of the first sealing material 320 is suppressed, resulting in excellent robustness as a building material.

[0066] The first sealing material 320 is formed by laminating the first sealing material with another material and then thermocompressing the laminate. The first sealing material 320 may contain the resin described above. In terms of the weather resistance of the first sealing material 320, the first sealing material preferably contains an uncrosslinked resin and a crosslinking agent. In this case, the uncrosslinked resin and the crosslinking agent in the first sealing material react with each other by thermocompression, thereby obtaining the first sealing material 320 containing the crosslinked resin. Known crosslinking agents such as organic peroxides can be used as the crosslinking agent. When laminated, the first sealing material is preferably in the form of a film or sheet.

[0067] The photovoltaic cell 330 has a function of converting light energy received on a first light-receiving surface 331 of the photovoltaic cell 330 into electrical energy. The photovoltaic cell 330 may have this function on only one of its light-receiving surfaces, or may have this function on both its other light-receiving surfaces.

[0068] Specifically, the photovoltaic cell 330 may be a silicon solar cell made of single crystal silicon, polycrystalline silicon, or amorphous silicon solar cell, or a GaAs, CIS, CIGS, CdTe, InP, Zn ３ P ２ , or Cu ２ The photovoltaic cell 330 may be a known solar cell such as a compound solar cell made of silicon dioxide (S), or an organic solar cell such as a perovskite type or a dye-sensitized type. As the photovoltaic cell 330, a single-crystal or polycrystalline silicon solar cell, a CIS solar cell, or a CIGS solar cell is more preferred, and a single-crystal silicon solar cell is most preferred.

[0069] The preferred embodiments of the materials and content of the second sealing material 340 are the same as those of the first sealing material 320. The thickness of the second sealing material 340 is not particularly limited, but is preferably 50 to 2,000 μm, more preferably 70 to 1,500 μm, even more preferably 100 to 1,200 μm, and particularly preferably 150 to 1,000 μm. When the thickness of the second sealing material 340 is 50 μm or more, it becomes easy to conform to the unevenness of the photovoltaic cells and wiring. When the thickness of the second sealing material 340 is 2,000 μm or less, it is economical and has excellent robustness as a building material because deformation of the second sealing material 340 is suppressed.

[0070] [Back Glass] The back glass 400 may be the same as or different from the glass substrate 220. From the viewpoint of using a single manufacturing material, the back glass 400 is preferably the same as the glass substrate 220. Examples of the back glass 400 include soda lime silicate glass, quartz glass, crystal glass, alkali-free glass, aluminosilicate glass, borosilicate glass, and barium borosilicate glass. Glass that is not highly transparent may also be used as the back glass 400.

[0071] The back glass 400 is preferably tempered glass that has been subjected to a tempering treatment. The back glass 400 may be surface-treated in terms of adhesion to the photovoltaic cell-containing sealing layer 300.

[0072] The thickness of the rear window 400 can be set arbitrarily depending on the type of road to be laid, etc. The thickness of the rear window 400 is preferably 1 to 70 mm. If the thickness of the rear window 400 is 1 mm or more, the durability is high and the rear window 400 is less likely to break. If the thickness of the rear window 400 is 70 mm or less, the rear window 400 becomes lighter, which makes it easier to lay the paving photovoltaic module 100.

[0073] The thermal expansion coefficient of the back glass 400 is preferably the same as that of the glass substrate 220 .

[0074] [Method for manufacturing a paving photovoltaic module] A method for manufacturing a paving photovoltaic module 100 includes, for example, a cover glass manufacturing process S1 for manufacturing a cover glass 200, and a sealing process S2 for sealing the photovoltaic cell 330 using the cover glass 200 by a known method.

[0075] <Cover Glass Manufacturing Process S1> In the cover glass manufacturing process S1, for example, first, a step S1-1A is performed in which a layer of glass frit, which is the raw material for binder 211, is formed on the surface of the first side 200a of the glass substrate 220. Next, a step S1-2A is performed in which particles A are embedded in the glass frit layer obtained in step S1-1A while some of the particles protrude from the surface. Next, a step S1-3A is performed in which the substrate obtained in step S1-2A is fired. In step S1-1A, the glass frit layer is formed, for example, by preparing a frit paste containing glass frit, a solvent, a resin, a filler, etc., and applying this paste to a predetermined thickness on the surface of the first side 200a. An overview of the technique is provided below.

[0076] (Frit Paste Materials) 1. Glass Frit The particle size of the glass frit is 1 to 10 μm.

[0077] 2. Resin After printing, the resin supports the glass frit and filler in the coating film. Specific examples of resins that are used include ethyl cellulose, nitrocellulose, acrylic resin, vinyl acetate, butyral resin, melamine resin, alkyd resin, and rosin resin. Ethyl cellulose, nitrocellulose, or acrylic resin is used as the base resin. Note that butyral resin, melamine resin, alkyd resin, and rosin resin are added to improve coating strength. The debindering temperature during firing is 350 to 400°C for ethyl cellulose, 200 to 300°C for nitrocellulose, and 300 to 350°C for acrylic.

[0078] 3. Solvent The solvent dissolves the resin and adjusts the viscosity required for printing. Furthermore, the solvent does not dry during printing but dries quickly during the drying process. The boiling point of the solvent is preferably 200 to 230°C. Solvents are blended together to adjust the viscosity, solid content, and drying speed. Specific examples of solvents include ether-based solvents (butyl carbitol (BC), butyl carbitol acetate (BCA), diethylene glycol di-n-butyl ether, dipropylene glycol butyl ether, tripropylene glycol butyl ether, butyl cellosolve acetate), alcohol-based solvents (terpineol, pine oil, Dowanol), ester-based solvents (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, butyl acetate), and phthalate-based solvents (DBP (dibutyl phthalate), DMP (dimethyl phthalate), DOP (dioctyl phthalate)) based on their compatibility with drying of the paste during printing. The solvents mainly used are terpineol and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, while DBP (dibutyl phthalate), DMP (dimethyl phthalate), and DOP (dioctyl phthalate) also function as plasticizers.

[0079] 4. Others: A surfactant may be used to adjust viscosity and promote frit dispersion. A silane coupling agent may also be used to modify the frit surface.

[0080] (Method of Preparing Frit Paste) A glass frit and a vehicle are prepared. Here, the vehicle is a mixture of a resin, a solvent, and a surfactant. Specifically, the vehicle is obtained by adding the resin, the surfactant, etc. to a solvent heated to 50°C to 80°C, leaving the mixture to stand for about 4 to 12 hours, and then filtering.

[0081] Next, the glass frit and vehicle are mixed in a planetary mixer. Then, if necessary, they are kneaded in a kneading machine to adjust the viscosity. Typically, the ratio is 60 to 80 wt % of glass frit and 20 to 40 wt % of vehicle. The method of mixing and kneading is not particularly limited, and other methods such as a crusher may also be used.

[0082] (Method of Applying Frit Paste) The method of applying the frit paste to the surface of the glass substrate 220 is not particularly limited, and application can be performed by a known method. Examples of methods for applying the frit paste to the surface of the glass substrate 220 include bar coater printing, applicator printing, doctor blade printing, screen printing, and die coat printing.

[0083] In step S1-2A, examples of the method for scattering particles A on the surface of the glass frit layer include a method for scattering particles A using a sieve or a method for scattering a mixture of particles A and a solvent by spraying.

[0084] In step S1-3A, the printed substrate is fired in a firing furnace. The firing process consists of drying the solvent, debinding to decompose and eliminate the resin, and firing to sinter and soften the glass powder. The debinding temperature is 350-400°C for ethyl cellulose, 200-300°C for nitrocellulose, and 300-350°C for acrylic. The debinding process involves heating in an air atmosphere for 30 minutes to an hour. The temperature is then raised to soften and sinter the glass. The firing temperature is between the softening temperature and softening temperature + 200°C, and the shape and size of the air bubbles remaining inside vary depending on the firing temperature. The substrate is then cooled, forming a glass film on the substrate. Note that the firing process is not limited to the above; the debinding process can be completed in a short time during the temperature rise process of glass softening and sintering by using a resin with a low decomposition temperature or reducing the amount of resin. Furthermore, physical strengthening can be achieved by blowing air on the substrate during cooling.

[0085] Furthermore, a technique called green sheet printing allows for the formation of thicker films. A film is formed on a PET film or the like using doctor blade printing or die coating printing, and then dried to obtain a green sheet. The green sheet is then thermocompressed onto a substrate using a roller or the like, and a fired film is obtained through a firing process similar to that for frit paste. By using multiple layers, even thicker glass films can be formed.

[0086] In the cover glass manufacturing process S1, first, a step S1-1B may be performed to prepare a mixture paste containing glass frit, which is the raw material of binder 211, and particles A on the surface of first side 200a of glass substrate 220. In this case, next, a step S1-2B is performed to form a layer having particles A embedded in the glass frit layer with some of the particles A protruding from the surface of the glass frit using the mixture paste obtained in S1-1B on the surface of first side 200a of glass substrate 220. Then, a step S1-3B is performed to fire the substrate obtained in step S1-2B.

[0087] In step S1-1B, a mixture paste containing, for example, glass frit, particles A, a solvent, and a resin is prepared. The solvent, resin, and other ingredients are the same as those described in step S1-1A. In the mixture paste, the content of particles A is preferably 1 to 70 wt %, more preferably 5 to 50 wt %.

[0088] In step S1-2B, the method for applying the mixture paste to the surface of the first side 200a of the glass substrate 220 is not particularly limited, and a known method may be used. For example, in step S1-2B, the method for applying the mixture paste to the surface of the first side 200a of the glass substrate 220 may be the same as that described in step S1-1A. In addition, step S1-3B is the same as step S1-3A.

[0089] <Sealing step S2> Examples of the step of sealing the photovoltaic cells 330 include a method of sealing the photovoltaic cells 330 by referring to the method for manufacturing a photovoltaic module described in International Publication No. 2021 / 106869 ("Photovoltaic module, manufacturing method thereof, and building exterior wall material using same").

[0090] The sealing step S2 of the photovoltaic cells 330 is not particularly limited, but may involve arranging the cover glass 200 obtained in the cover glass manufacturing step, the first sealing material 320, the photovoltaic cells 330, and the second sealing material 340 in this order, and then heat-pressing them to seal the photovoltaic cells 330. This results in the paving photovoltaic module 100 of this embodiment in which the cover glass 200, the first sealing material 320, the photovoltaic cells 330, and the second sealing material 340 are stacked in this order.

[0091] The heating temperature during thermocompression bonding is preferably 100 to 200° C., particularly preferably 130 to 170° C. The thermocompression bonding time is preferably 2 to 120 minutes, particularly preferably 5 to 60 minutes.

[0092] 6 is a schematic perspective view showing an example of the structure of a cover glass 600 provided in a paving photovoltaic module according to embodiment 2. The paving photovoltaic module according to embodiment 2 is the same as that described in embodiment 1, except that it includes a cover glass 600 instead of the cover glass 200. Therefore, a description of the configuration of the paving photovoltaic module according to embodiment 2 other than the cover glass 600 will be omitted.

[0093] [Cover Glass] Fig. 6 is a schematic cross-sectional view showing an example structure of a cover glass 600. The cover glass 600 includes a particle layer 610 and a glass substrate 620. As shown in Fig. 6, the particle layer 610 is disposed on a first side 600a of the cover glass 600. The glass substrate 620 is disposed on a second side 600b of the cover glass 600. The particle layer 610 includes a binder 611, particles 612, and particles 613. The particle layer 610 includes particles 612 protruding from the surface of the first side 600a. The particles 612 are the particles A described above. The particles 613 are particles B described below.

[0094] <Particle Layer> The particle layer 610 differs from the particle layer 210 shown in Fig. 2 in that it contains particles 613. The properties and preferred aspects of the particle layer 610 are similar to those of the particle layer 210, and therefore a description thereof will be omitted. The properties and preferred aspects of the binder 611 and the particles 612 are similar to those of the binder 211 and the particles A described above, and therefore a description thereof will be omitted.

[0095] <<Particles B>> Particles 613 are particles B. Particles B are crystalline particles. From the viewpoint of increasing the abrasion resistance of the cover glass 600, particles B have a Mohs hardness of 6.0 or more, preferably 6.5 or more. Examples of crystalline particles include Al ２ O ３ (alumina), ZrO ２ (zirconia), SiO ２ (silica) and ZrSiO ４ In order to reduce costs, the particles B may be made of metal oxides such as Al (zirconium). ２ O ３ is preferred.

[0096] The particle size of particle B is smaller than that of particle A. The particle size of particle B is 0.1 to 10 μm. From the viewpoint of suppressing aggregation of particle B, the lower limit of the particle size of particle B is preferably 0.2 μm, more preferably 0.3 μm, and even more preferably 0.5 μm. The upper limit of the particle size of particle B is preferably 9 μm, more preferably 8 μm, and even more preferably 7 μm.

[0097] The particle size of particle B is a circle-equivalent diameter obtained by cutting cover glass 600, polishing the cross section, and taking a cross-sectional image of particle layer 610 using an SEM or the like to measure the area of ​​the particle in a plan view, and determining the diameter of a circle having the same area as the particle size. Furthermore, "particles having a particle size of 0.1 to 10 μm" means that the number of particles having a particle size of 0.1 to 10 μm is 50% or more, preferably 60% or more, and more preferably 65% ​​or more of the total number of particles.

[0098] The shape of the particles B is not particularly limited, and may be polygonal, plate-like, rod-like, spherical, or irregular. The shape of the particles B may be either a smooth shape such as a sphere or an irregular shape with sharp corners. For example, the particles B may be SiO２ , Al ２ O ３ , ZrSiO ４ , or ZrO ２ The particles may be irregularly shaped particles obtained by crushing crystals of metal oxides such as those mentioned above.

[0099] The volume ratios of the particles B and the binder 611 in the entire particle layer 210 are V Ｂ , V Ｆ Then, V Ｂ / (V Ｆ +V Ｂ ) is 0.4 or less. Ｂ / (V Ｆ +V Ｂ ) is 0.4 or less, sufficient wear resistance can be obtained.

[0100] Volume ratio V Ｂ is calculated by calculating the sum of the areas of all particles in the field of view in the image obtained when measuring the particle size of particle B, and dividing this sum by the total field of view area. Using five images, the average value calculated for each image is taken as the volume ratio V Ｂ The volume ratio V Ｆ is calculated by calculating the sum of the areas of all particles in the field of view in the image obtained when measuring the particle size of particle B, subtracting this sum from the total field of view area, and dividing the result by the total field of view area. Using five images, the average value calculated for each image is taken as the volume ratio V Ｆ Let's say.

[0101] EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[0102] [Study on particle size of particle A] As a sample according to the example, a cover glass sample was prepared by the following method.

[0103] (Raw materials) Particle A: white alumina particles, particle sizes #24, #46, #60, #120, #180, #400, #1000 Glass frit: YFT-531E, manufactured by AGC Electronics Inc., softening point: 589°C Solvent: butyl carbitol acetate (BCA) Resin: acrylic binder for sintering KC-1700P, manufactured by Kyoeisha Chemical Co., Ltd. Dispersant: BYK180, manufactured by BYK-Chemie Glass substrate: soda lime glass, size: 150 x 100 mm, thickness: 3 mm, softening point: 740°C

[0104] First, the resin and solvent were weighed so that the resin ratio was 40% by mass, and mixed using a homogenizer while bathing in hot water to prepare a vehicle. Next, 9.99 g of vehicle and 0.4 g of dispersant were mixed using a rotation / revolution mixer, and then 13.09 g of glass frit and 6.91 g of particles A with a particle size of 1000 were added and further mixed to prepare a frit paste. With these blending amounts, the solid content contained 60 vol% of frit and 40 vol% of particles.

[0105] Next, a metal plate made of 0.5 mm thick SUS plate with a 140 × 90 mm square opening was placed on the glass substrate, and an appropriate amount of frit paste was poured onto it. A urethane squeegee was pressed against the mask and moved over the mask to fill the opening with the frit paste without any gaps, and then the metal mask was removed. In this way, a frit paste film was formed on the glass substrate.

[0106] The resulting substrate was placed in a baking furnace and heated in an air atmosphere from room temperature to 250°C over 1.5 hours to volatilize the solvent, then heated to 400°C over 4 hours and held at 400°C for 4 hours to decompose and remove the resin, after which the furnace was allowed to cool naturally. The substrate was then conveyed by a belt through a conveyor furnace maintained at 680°C for 9 minutes to melt and sinter the glass frit. The resulting cover glass was used as the sample.

[0107] In a similar manner, cover glasses were prepared as samples using particles A of particle sizes #46, #60, #120, #180, and #400 instead of particles A of particle size 1000. For particles of particle size #24, a metal plate with a thickness of 1.0 mm was used for preparation, since the particle size is large.

[0108] (Slip resistance value BPN) The seven types of cover glasses thus obtained, each having different particle sizes, were subjected to measurement of the slip resistance value BPN. The slip resistance value BPN was measured in accordance with ASTM E303 using a pendulum-type skid resistance tester manufactured by CONTROLS.

[0109] (Tactile Safety) On the other hand, when used for road paving, it is necessary to ensure safety by providing sufficient slip resistance while also preventing cuts when falling or putting one's hands on the surface. This is used as an index of tactile safety, and a sensory test was conducted by three people. If all three people judged it to be no problem, they were given a rating of ◯, if their judgments differed, they were given a rating of △, and if all people judged it to be a problem, they were given a rating of ×.

[0110] Table 1 below shows the particle size of particles A used in the samples of Examples 1 to 7, the measurement results of the slip resistance value BPN, and the sensory test results for tactile safety. A graph summarizing the measurement results of the slip resistance value BPN is shown in Figure 7. Examples 1 to 5 are working examples, and Examples 6 and 7 are comparative examples.

[0111]

[0112] As indicated in the Tokyo Metropolitan Welfare Town Planning Ordinance and other regulations, a BPN value of 40 or more is often required for sidewalks. Therefore, as shown in Figure 7, it can be seen that the particle size of particle A needs to be approximately 50 μm or more. On the other hand, it was found that the tactile safety decreases as the particle size of particle A increases, with the allowable limit being approximately 1000 μm. Based on the above, it was determined that a particle size of 0.05 to 1 mm is appropriate for particle A.

[0113] [Study on the ratio of particles A to particles B] As samples according to the example, cover glass samples were prepared by the following method.

[0114] (Raw materials) Particle A: white alumina particles, particle size #120 Particle B: white alumina particles, particle size #4000 Glass frit: YFT-531E, manufactured by AGC Electronics Inc., softening point: 589°C Solvent: butyl carbitol acetate (BCA) Resin: acrylic binder for sintering KC-1700P, manufactured by Kyoeisha Chemical Co., Ltd. Dispersant: BYK180, manufactured by BYK-Chemie Glass substrate: soda lime glass, size: 150 x 100 mm, thickness: 3.2 mm, softening point: 740°C

[0115] A vehicle was prepared in the same manner as described above, and the vehicle and dispersant were mixed in a rotation / revolution mixer. Glass frit, particles A, and particles B were then added and further mixed to prepare a frit paste. The respective blend amounts were adjusted so that the volume ratios of frit, coarse particles, and fine particles in the solid content were as shown in Table 2, and a total of 16 types of frit paste were prepared. A frit paste was also prepared in the same manner for samples containing neither particles A nor particles B. In all samples, the particle size of particles A was #120 and the particle size of particles B was #4000, with only the blending ratios being varied. This frit paste was used to form a film on a 0.5 mm thick metal plate in the same manner as described above, and then fired. The resulting cover glass was used as a sample.

[0116] (Taber Test) The abrasion resistance of the 17 types of cover glasses thus obtained, each having a different compounding ratio of particles A and particles B, was evaluated by the Taber test. The abrasion resistance evaluation by the Taber test was carried out as follows. A rotary abrasion tester (manufactured by Toyo Seiki Seisakusho) was used, and a CS-17 (manufactured by Toyo Seiki Seisakusho) was used as the abrasion wheel, and a 2.45 N weight was attached to each of the two arms, so that the total load was 4.9 N with the arms. After every 1000 rotations of abrasion, the sample was removed, the abraded material was removed, and the weight loss was measured, and the test was continued until a total of 5000 rotations had been reached.

[0117] (Slip resistance value BPN) The slip resistance value BPN was measured by the same method as described above. The results of the Taber test and the measurement of the slip resistance value BPN are shown in Table 2. Examples 11 to 17 and 19 to 23 are working examples, and Examples 18 and 24 to 27 are comparative examples.

[0118]

[0119] Using the results of Table 2, a graph showing the relationship between the volume ratio of particle A and the amount of wear is shown in Figure 8. Using the results of Table 2, a graph showing the relationship between the volume ratio of particle A and the amount of slippage is shown in Figure 9. As shown in Figure 9, it can be seen that the slippage resistance increases as the ratio of particle A increases, and that 15 vol% or more of particle A is required to achieve a BPN of 40 or more. On the other hand, as shown in Figure 8, with regard to wear resistance, the amount of wear increases as the ratio of particle A increases, and it can be seen that an excessively high ratio of coarse particles is not desirable.

[0120] FIG. 10 shows the reflected light images of Examples 11 and 23 taken under an optical microscope. As shown in FIG. 10, a smooth surface was obtained when the particle A content was 40 vol%, but holes were observed on the surface when the particle A content was 50 vol%. Since the accumulation of dust in the surface holes can cause a decrease in power generation efficiency, it is considered undesirable to have too many holes on the surface. Therefore, the volume ratio of particle A is preferably 60 vol% or less, which does not result in too many holes. Based on the above, it was determined that a volume ratio of particle A of 15 to 60 vol% is suitable.

[0121] Next, Fig. 11 is a graph showing the relationship between the volume ratio of particle B / (volume ratio of frit + volume ratio of particle B) and the abrasion resistance, based on the results of Table 2. It can be seen that as the ratio of particle B is increased, the abrasion amount decreases and the abrasion resistance improves up to about 30%, but when the ratio exceeds this, the abrasion amount increases sharply.

[0122] 12 shows the reflected light images of Examples 25 and 27 after the Taber test. When the content of particles B was 0%, abrasion scratches were clearly visible, but when the content of particles B was 30%, it was found that the abrasion scratches were reduced, and it was found that the abrasion resistance was improved by adding particles B.

[0123] Figure 13 shows optical microscope images of Examples 19 to 22, i.e., when the amount of particle A was fixed at 40 vol% and the amount of particle B was varied. When the amount of particle B was up to 30%, the surface gloss due to the molten frit was visible, but when the amount of particle B was 50%, the gloss disappeared, and it was clear that the particle B was no longer covered by the frit. Normally, particle B would be held and fixed by the molten frit glass, but in this state, the fixation of particle B was weak, which is thought to lead to a decrease in abrasion resistance. From these results, it was determined that a volume ratio of particle B / (volume ratio of frit + volume ratio of particle B) of 40% or less is appropriate.

[0124] [Measurement of Output Power When Pigment is Added] As a sample according to the embodiment, a sample of a photovoltaic module for paving was prepared by the following method.

[0125] (Raw Materials) Pigment: [Blue] 42-250a (CoAl2O4) manufactured by TOMATEC, [Red] Iriodin 524 manufactured by Merck, [Gold] Iriodin 323 manufactured by Merck. Particle A: white alumina particles, particle size #120. Glass frit: YFT-531E manufactured by AGC Electronics Inc., softening point: 589°C. Solvent: butyl carbitol acetate (BCA). Resin: acrylic binder for sintering KC-1700P manufactured by Kyoeisha Chemical Co., Ltd. Dispersant: BYK180 manufactured by BYK-Chemie. Glass substrate: soda lime glass, size: 100 x 100 mm, thickness: 3.2 mm, softening point: 740°C. Back glass: soda lime glass, size: 100 x 100 mm, thickness: 3.2 mm Interlayer film for laminated glass: VistaSolar, EV resin, 521,68 Photovoltaic cell: polycrystalline silicon solar cell

[0126] A vehicle was prepared in the same manner as described above, and then 9.94 g of the vehicle and 0.4 g of the dispersant were mixed in a rotation / revolution mixer. 0.07 g of the blue pigment, 12.89 g of glass frit, and 7.04 g of particles A were added and further mixed to prepare a frit paste containing the blue pigment. This blending amount resulted in a pigment content of 0.5 vol% of the solid content.

[0127] Next, a metal plate made of 0.5 mm thick SUS plate with a 90 mm square opening was placed on the glass substrate, and an appropriate amount of frit paste was poured on top. A urethane squeegee was pressed against the mask and moved over the mask to fill the opening with the frit paste without any gaps, and then the metal mask was removed. In this way, a frit paste film was formed on the glass substrate.

[0128] The resulting substrate was placed in a firing furnace and heated in an air atmosphere from room temperature to 250°C over 1.5 hours to volatilize the solvent, then heated to 400°C over 4 hours and held at 400°C for 4 hours to decompose and remove the resin, after which the furnace was allowed to cool naturally. The substrate was then conveyed by a belt through a conveyor furnace maintained at 680°C for 9 minutes to melt and sinter the glass frit. This resulted in the production of a blue cover glass.

[0129] In the same manner, red and gold cover glasses were obtained by using 0.08 g of red pigment and 0.08 g of gold pigment instead of the blue pigment. Also, a cover glass without pigment was prepared by using 12.97 g of glass frit without adding any pigment.

[0130] Next, the obtained cover glass, the first sealing material, the photovoltaic cell whose power generation efficiency had been measured, the second sealing material, and the back glass were stacked in this order, vacuum-packed, and then heated in an oven at 90°C for 45 minutes to temporarily bond them.The packaging material was then removed, and the assembly was again heated in an oven at 130°C for 30 minutes.In this way, a photovoltaic module for paving was produced.In addition, a photovoltaic module using a cover glass with only a glass substrate without a particle layer, i.e., an anti-slip layer, was also produced as a reference.

[0131] (Appearance) Each of the photovoltaic modules produced had an appearance with a color expected from the added pigment.

[0132] (Reflectance Measurement) A spectrophotometer V-670ST manufactured by JASCO Corporation was used for reflectance measurement. The reflectance measurement results are shown in Figure 14. From the appearance and reflectance measurement results, it can be seen that the particle layer exhibits the desired color, and a photovoltaic module for paving with design properties has been produced.

[0133] (Measurement of Output Characteristics) The output characteristics of the solar cell were measured for the fabricated photovoltaic module. To measure the output characteristics, a solar simulator manufactured by Yamashita Denso Co., Ltd. was used to irradiate the solar cell with simulated sunlight, and a source meter was used to measure the current-voltage characteristics. From the results, the output power Pmax at the optimal operating point where the product of current and voltage is greatest, and the short-circuit current Isc when the external voltage is 0 V were calculated. Furthermore, the changes in Pmax and Isc values ​​before and after modularization, i.e., the changes in Pmax and Isc values ​​when the photovoltaic cell is in a standalone state and when a cover glass is placed on top of it, were also calculated. These results are shown in Table 3.

[0134]

[0135] The results shown in Table 3 show that even with the design, the output power is at least 50% higher than that of a panel without a particle layer. Although there is a trade-off between power generation efficiency and color intensity, the color can be adjusted by adjusting the pigment concentration as needed.

[0136] The present invention has been described above in accordance with the above-mentioned embodiment, but the present invention is not limited to the configuration of the above-mentioned embodiment, and naturally includes various modifications, alterations, and combinations that a person skilled in the art can make within the scope of the invention as defined in the claims of this application.

[0137] This application claims priority based on Japanese Patent Application No. 2023-205792, filed December 6, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0138] 100 Photovoltaic module for paving 200, 600 Cover glass 200a, 600a First side 200b, 600b Second side 210, 610 Particle layer 211, 611 Binder 212, 612 Particle A 613 Particle B 220, 620 Glass substrate 300 Photovoltaic cell-containing sealing layer 310 Sealing layer 320 First sealing material 330 Photovoltaic cell 331 First light-receiving surface 340 Second sealing material 400 Back glass

Claims

1. A paving photovoltaic module comprising: a cover glass; a photovoltaic cell; and a sealing layer for sealing the photovoltaic cell, wherein the cover glass is disposed on a light receiving surface side of the photovoltaic cell; the cover glass has a first side and a second side, and the photovoltaic cell is disposed on the second side; the cover glass comprises a particle layer and a glass substrate, the particle layer is disposed on the first side, and the glass substrate is disposed on the second side; the particle layer comprises particles A protruding from a surface thereof and a binder; the binder is a fired product of glass frit; the particle A has a particle diameter of 0.05 mm or more and 1 mm or less; the particles A are bonded to the glass substrate using the binder; and the volume ratio V of the particles A in the entire particle layer is 0.05 mm or more and 1 mm or less. Ａ A photovoltaic module for paving, wherein the ratio of the surface area to the surface area of ​​the photovoltaic module is 15% or more and 60% or less.

2. The photovoltaic module for paving according to claim 1, wherein the particle layer contains particles B, and the particle diameter of the particles B is 0.1 μm or more and 10 μm or less.

3. The photovoltaic module for paving according to claim 2, wherein the particles B are crystalline particles, and the Mohs hardness of the particles B is 6.5 or more.

4. The volume ratio of the particles B and the binder in the particle layer is V Ｂ , V Ｆ Then, V Ｂ / (V Ｆ +V Ｂ 4. The photovoltaic module for paving according to claim 2 or 3, wherein the coefficient of friction is 0.4 or less.

5. The photovoltaic module for paving according to claim 1 or 2, wherein the particulate layer has air bubbles.

6. The number of bubbles contained in the particle layer is 100 / mm ３ The photovoltaic module for paving according to claim 5 .

7. The photovoltaic module for paving according to claim 1 or 2, wherein the particle layer is patterned into a predetermined shape when viewed from above.

8. The photovoltaic paving module of claim 1 or 2, wherein the composition of the glass substrate and the composition of the binder are different.

9. The photovoltaic module for paving according to claim 1 or 2, wherein the strain point of the glass substrate is at least 30° C. higher than the softening point of the binder.

10. The photovoltaic module for paving according to claim 1 or 2, having the relationship: thermal expansion coefficient of said glass substrate ≧ thermal expansion coefficient of said binder ≧ thermal expansion coefficient of said particles.

11. The photovoltaic module for paving according to claim 1 or 2, wherein the material of said particles B is one or more selected from the group consisting of alumina, zirconia, silica, and zircon.

12. The photovoltaic module for paving, according to claim 1 or 2, wherein the particulate layer contains pigments made of inorganic materials.

13. The paving photovoltaic module of claim 12, wherein the pigment material is a metal oxide.

14. The photovoltaic module for paving according to claim 12, wherein the concentration of said pigment in said particulate layer is 5 vol % or less.

15. A cover glass to be placed on the light receiving surface side of a photovoltaic cell, the cover glass having a first side and a second side, the photovoltaic cell being placed on the second side, the cover glass including a particle layer and a glass substrate, the particle layer being placed on the first side and the glass substrate being placed on the second side, the particle layer including particles A protruding from a surface thereof and a binder, the binder being a fired glass frit, the particle A having a particle diameter of 0.05 mm or more and 1 mm or less, the particles A being bonded to the glass substrate using the binder, and a volume ratio V of the particles A in the entire particle layer being 0.05 mm or more and 1 mm or less. Ａ A cover glass, wherein the percentage of the surface area is 15% or more and 60% or less.

16. The cover glass according to claim 15, wherein the particle layer contains particles B, and the particle diameter of the particles B is 0.1 μm or more and 10 μm or less.

17. The photovoltaic module for paving according to claim 2, wherein the particles B are crystalline particles, and the Mohs hardness of the particles B is 6.0 or more.

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