JP2014041998A - Light collecting plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light collecting plate capable of enhancing light collection efficiency of the light receiving part of a solar cell by controlling light transmission and reflection.SOLUTION: A light collecting plate (11) is provided in a light receiving part of a solar cell (42). The light collecting plate (11) has a reflection layer (13) having a reflection surface (24) facing the light receiving part and a plurality of light-transmissive spherical bodies (14) penetrating through the reflection layer (13). The protruded distance from the reflection surface (24) of the spherical body (14) is smaller in comparison with that from the rear surface (23) opposite to the reflection surface (24).

Description

  The present invention is a light collector provided in a light receiving portion of a solar cell.

  In recent years, photovoltaic power generation has attracted attention as a power generation system with a low environmental load. A general solar power generation device has a fixed flat plate structure in which solar cell elements are spread without gaps.

  Conventionally, only the light directly irradiating the light receiving part of solar power generation has been used. In recent years, various methods for efficiently concentrating sunlight on solar cell elements are being developed. For example, Patent Document 1 proposes a light receiving body that covers the entire light receiving portion of a solar cell and has a prism portion. This photoreceptor improves the light collection efficiency of the solar cell by controlling the transmission and reflection of light incident from the light source using a prism. However, this optical receiver has a complicated optical design of the prism included in the optical receiver, and in addition, when manufacturing (molding) the optical receiver, it is difficult to precisely form the prism according to the optical design. If the prism is not molded according to the optical design, the light collection efficiency of the photoreceptor becomes small. For this reason, conventional photoreceptors have insufficient control of light transmission and reflection, and there is room for improvement in light collection efficiency.

JP 9-139518 A

  The objective of this invention is providing the light-condensing plate which can improve the condensing efficiency of the light-receiving part of a solar cell more by controlling permeation | transmission and reflection of light.

  The present invention is a light collecting plate provided in a light receiving portion of a solar cell, wherein the light collecting plate includes a reflective layer having a reflective surface facing the light receiving portion, and a plurality of light-transmitting materials penetrating the reflective layer. A light-collecting plate characterized in that a protruding distance of the spherical body from the reflecting surface is smaller than a protruding distance from the back surface opposite to the reflecting surface. In such a light collector, light transmission and reflection are more efficiently controlled. The photovoltaic power generation module using the light collector of the present invention exhibits excellent effects of improving the light collection efficiency and increasing the amount of power generation.

  The light collector of the present invention preferably includes a bonding layer on the back surface of the reflective layer, the sphere being projected and laminated. If it is such a light-condensing plate, the said coupling layer will couple | bond and hold | maintain the said spherical body more firmly, and the intensity | strength of a light-condensing plate will increase, for example, can be used suitably outdoors.

  The reflective layer is preferably a metal layer. If it is such a reflection layer, since the condensing plate of this invention can control permeation | transmission and reflection of light, and can improve condensing efficiency more, it is preferable.

  The refractive index of the spherical body is preferably in the range of 1.30 to 2.30. If it is the refractive index of such a range, the light-condensing plate of this invention is preferable since it can control the permeation | transmission and reflection of light, and can improve condensing efficiency more.

  The light collector of the present invention can control the transmission and reflection of light, and can further improve the light collection efficiency. Therefore, the photovoltaic power generation module using the light collector of the present invention has improved light collection efficiency and increased power generation.

FIG. 1 is a diagram showing a structure in a cross section of a light collector according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a relationship between a light collector according to an embodiment of the present invention and light incident on the light collector. FIG. 3 is a schematic diagram of the positional relationship between the reflective layer and the spherical body of the light collector according to the embodiment of the present invention. FIG. 4 is an enlarged view of a plan view of the first surface side of the light collector according to the embodiment of the present invention. FIG. 5 is an enlarged view of a plan view of the second surface side of the light collector according to the embodiment of the present invention. FIG. 6 is a diagram illustrating a structure in a cross section of a light collector according to an embodiment of the present invention and a solar power generation module having the light collector.

  Hereinafter, preferred embodiments of the light collector of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a cross-sectional structure of a light collector according to an embodiment of the present invention.

  As shown in FIG. 1, the main configuration of the light collector 11 of the present embodiment includes a reflective layer 13 having a reflective surface 24 and a plurality of light-transmitting spherical bodies 14 penetrating the reflective layer 13. The protruding distance from the reflecting surface 24 of the spherical body 14 is smaller than the protruding distance from the back surface 23 on the opposite side to the reflecting surface 24. The plurality of spherical bodies 14 are arranged in a single layer and close to closest packing with respect to the back surface 23 of the reflecting surface 24 of the reflecting layer 13. Note that FIG. 1 illustrates a light collector 11 having a bonding layer 12 on which a spherical body 14 protrudes from the back surface 23 and is laminated.

  The light collector 11 has a first surface 21 and a second surface 22. The first surface 21 is a part of the back surface 23 of the reflective layer 13 and a part of the spherical body 14, or a part of the coupling layer 12 and the spherical body 14 when the light collector 11 includes the coupling layer 12 as shown in FIG. In addition, the second surface 22 is composed of the reflective surface 24 of the reflective layer 13 and a part of the spherical body 14. In FIG. 1, most of the light incident on the first surface 21 side of the light collector 11 passes through the spherical body 14 and exits from the second surface 22 side. Further, most of the light incident on the second surface 22 side of the light collector 11 is reflected by the reflective surface 24 of the reflective layer 13.

  FIG. 2 is a diagram schematically showing the light collector 11 according to the embodiment of the present invention and the light incident on the light collector 11. The light 32 incident on the first surface 21 a of the light collector 11 a from the light source 31 passes through the light-transmitting spherical body 14 a and is emitted from the second surface 22 a as light 33. At this time, the light 32 incident on the first surface 21a is refracted and condensed by the spherical body 14a and is emitted from the second surface 22a. Therefore, most of the light is transmitted through the light collector 11a. To do. On the other hand, most of the light 34 incident on the second surface 22b side of the light collector 11b from the light source 31 is reflected as light 35 by the reflective surface of the reflective layer 13b of the light collector 11b. Therefore, when the condensing plate 11a and the condensing plate 11b are arranged so that the reflection layers 13a and 13b face each other as in the illustrated positional relationship, the light incident from the light source 31 on one condensing plate, for example, 11a, is Most of the light transmitted from the light source 31 is reflected by the other light collecting plate, for example, 11b. In FIG. 2, a spherical body 14 having a refractive index of about 1.9 is shown.

  In FIG. 1, the reflective layer 13 is a layer that reflects light incident on the second surface 22 side of the light collector 11 from a light source (not shown). The reflective layer 13 has a reflective surface 24 and a back surface 23 on the opposite side. The reflective layer 13 is preferably a metal layer or a resin layer containing a white pigment. If the reflective layer 13 is a metal layer, the reflective surface 24 is preferable because the light is specularly reflected, and thus the reflectance is high and there is no loss of light during reflection. The metal is preferably aluminum, silver, rhodium, and stainless steel because of high light reflectivity, and aluminum, silver, and rhodium are more preferable because the wavelength dependency of light reflectivity is small. When the light collector 11 of the present invention is used in a solar power generation module, it is preferable that the metal is aluminum or rhodium because light absorption in the ultraviolet region in the reflective layer 13 is small and power generation efficiency is increased.

  When the reflective layer 13 is a metal layer, the metal layer is not particularly limited, but can be provided, for example, on the bonding layer 12 described later by a vapor deposition method, a sputtering method, and a plating method.

  The reflective layer 13 can be provided by laminating a resin containing metal powder on the bonding layer 12 described later by a coating method or a printing method, for example. Although the metal powder is not particularly limited, aluminum flakes, nickel flakes, and copper flakes can be exemplified, and the resin is not particularly limited, but examples thereof include poly (meth) acryl, polyester, and polyvinyl chloride. Such a configuration is preferable because the reflective layer 13 has a high light reflectance and there is no loss of light during reflection.

  If the reflective layer 13 is a resin layer containing a white pigment, the white pigment can be, for example, alumina, barium sulfate, barium carbonate, zinc oxide, titanium oxide, barium titanate, strontium titanate, calcium carbonate, magnesium carbonate, forsterite. , And wollastonite can be preferably used. These white pigments can be suitably used singly or in combination. Moreover, various glass beads and pearl pigments can be used as the white pigment, and hollow glass beads can be used as the glass beads. In addition, it is preferable if the particle size of the white pigment is 5 μm or less because the reflectance at the reflective layer 13 is increased. The resin used for the resin layer is not particularly limited, but can be suitably used as long as it is poly (meth) acryl, polyester, or polyvinyl chloride.

  In the light collector 11 of the present invention, the reflective surface 24 provided in the reflective layer 13 needs to reflect light including the absorption band width of the photovoltaic power generation module. Therefore, when the reflective layer 13 is a resin layer containing a white pigment, it is preferable that the white pigment is alumina or barium sulfate because light absorption in the absorption band width of the photovoltaic power generation module in the reflective layer 13 is small. .

  In addition, the reflectance of the reflective surface 24 can be calculated | required using a spectrophotometer in the condition which used the background as black felt according to JISK7375. The reflectance of the reflecting surface 24 is preferably 50% or more. The reflectance in the present invention is a value obtained by averaging the reflectance at each wavelength in a light wavelength region of 250 nm to 800 nm, and is a relative value with the reflectance of barium sulfate used as a standard white plate as 100%. It is.

  The spherical body 14 is a layer that transmits light. The light collector 11 of the present invention has a plurality of spherical bodies 14. The spherical bodies 14 are arranged on the back surface 23 of the reflective layer 13 in a single layer and in a state close to closest packing. Due to such a configuration, the transmittance of light incident on the first surface 21 side of the light collector 11 of the present invention is increased. The spherical bodies 14 are not arranged according to a predetermined rule if the shortest distance between adjacent spherical body surfaces is close to the average radius of the spherical bodies 14 penetrating the reflective layer 13. Also good.

  FIG. 3 is a schematic diagram of the positional relationship between the reflective layer 13 and the spherical body 14 of the light collector 11 according to the embodiment of the present invention. For schematic representation, only one spherical body 14 is illustrated. The light collector 11 has a spherical body 14 that penetrates the reflective layer 13. In FIG. 3, at least a part of the spherical body 14 is exposed on any of the reflective surface 24 and the back surface 23 of the reflective layer 13. Hereinafter, the positional relationship between the reflective layer 13 and the spherical body 14 will be described in detail. In the light collector 11, the protruding distance of the spherical body 14 from the reflecting surface 24 is smaller than the protruding distance from the back surface 23 opposite to the reflecting surface 24. That is, in FIG. 3, the distance between the back surface 23 of the reflective layer 13 and the farthest point of the spherical body 14 on the back surface 23 side of the reflective layer 13 is L, the reflective surface 24 of the reflective layer 13, and the reflective layer 13 When the distance from the reflective surface 24 side to the farthest point of the spherical body 14 is represented as R, the positional relationship between the spherical body 14 and the reflective layer 13 is L> R. L in FIG. 3 is a protruding distance from the back surface 23 of the spherical body 14, and R is a protruding distance from the reflecting surface 24 of the spherical body 14. Due to such a configuration, the light collector 11 of the present invention keeps the reflectance at the reflection surface 24 of the reflection layer 13 high, while the spherical body 14 refracts and collects light and sufficiently transmits the light. be able to. The light collector 11 of the present invention controls light transmission and reflection, and exhibits an excellent feature of high light collection efficiency. The protruding distance of the spherical body 14 can be determined by observing and measuring the cross section of the light collector 11 using a microscope such as an optical microscope or an electron microscope.

  Since the light incident on the first surface 21 of the light collector 11 can be efficiently refracted and condensed by the spherical body 14, the protrusion distance L from the back surface 23 of the spherical body 14 is preferably as large as possible. A preferable range of the size of the protrusion distance L from the back surface 23 of the spherical body 14 is 50% or more, preferably 75% or more, more preferably 95% or more, when the diameter of the spherical body 14 is 100%. Moreover, the magnitude | size of the protrusion distance R from the reflective surface 24 of the spherical body 14 becomes like this. Preferably it is 25% or less, More preferably, it is 5% or less. Even if the protruding distance R of the spherical body 14 from the reflection surface 24 is almost as small as 0, if the spherical body 14 is partially exposed on the reflection surface 24, the light collector 11 collects and transmits light. Can be made.

  The transmittance of light from the first surface 21 side of the light collector 11 can be obtained using a spectrophotometer according to JIS K7375. The transmittance of the light collector 11 is 50% or more, preferably 70% or more, more preferably 85% or more. The transmittance in the present invention is a value obtained by averaging the transmittance at each wavelength in the light wavelength region of 250 nm to 800 nm, and is a relative value with the air transmittance being 100%. In the present invention, light transmittance means that the transmittance is 50% or more.

  Although the diameter of the spherical body 14 does not have a restriction | limiting in particular, For example, it is the range of 0.1 micrometer-1000 micrometers, Preferably it is the range of 10 micrometers-500 micrometers. When the diameter is 0.1 μm or more, it is preferable that a plurality of spherical bodies 14 are not easily aggregated during the production of the light collector 11, and the arrangement in a single layer is easy. Further, it is preferable that the diameter is 0.1 μm or more because light loss due to light scattering and diffraction can be suppressed and the transmittance of light from the first surface 21 side of the light collector 11 is increased. Moreover, if the said diameter is 1000 micrometers or less, since the light-condensing plate 11 of this invention can be reduced in weight and the loss | disappearance with the time of the spherical body 14 from the light-condensing plate 11 does not occur easily, it is preferable. The light collector 11 of the present invention is usually installed and used in a solar power generation module outdoors. The light collector 11 of the present invention is preferable because, for example, the spherical body 14 is not lost even after one year or more and the light transmittance of the light collector 11 can be maintained high. In addition, the diameter of the spherical body 14 can be measured with a microscope.

  The preferable range of the refractive index of the spherical body 14 is 1.30 to 2.30, more preferably 1.70 to 2.10. If the refractive index is 1.30 or more, when light is incident on the first surface 21, the light is refracted and condensed by the spherical body 14 and can be emitted from the second surface 22. It is preferable because light can be collected efficiently, and if it is 2.30 or less, the light incident on the first surface 21 is refracted and collected by the spherical body 14 when passing through the second surface 22. It is preferable because light can be focused in the vicinity of the second surface 22 outside the spherical body, the spherical surface, or outside the spherical body, and can be emitted from the second surface 22, that is, the light collector 11 can appropriately transmit the light. For example, as shown in FIG. 2, when a spherical body 14 having a refractive index of about 1.9 is used, the light incident on the first surface 21 of the spherical body 14 and refracted and condensed is a spherical body. A focal point is formed in the vicinity of the interface between the air and the air, and the light is emitted from the second surface 22. The refractive index of the spherical body 14 can be measured by an ordinary refractive index measurement method such as Abbe method.

  The spherical body 14 is not particularly limited, but glass beads, silica beads, inorganic spherical bodies represented by transparent ceramic beads, acrylic resin beads, polystyrene resin beads, acrylic-styrene copolymer beads, melamine resin beads, urethane resin Resin spheres represented by beads can be suitably used.

  Examples of the inorganic spherical body that can be suitably used for the spherical body 14 include Nika beads HB series (manufactured by Nippon Carbide Industries Co., Ltd.) and Nika beads MB series (manufactured by Nippon Carbide Industries Co., Ltd.). , Techpolymer MBX-12 (manufactured by Sekisui Plastics Industry Co., Ltd.), Techpolymer SBX-12 (manufactured by Sekisui Plastics Industry Co., Ltd.), Art Pearl GR-400 transparent (manufactured by Negami Industrial Co., Ltd.), Art Pearl SE-050T (Negami Kogyo Co., Ltd.), Art Pearl P-400T (Negami Kogyo Co., Ltd.), and Opto Bead 10500M (Nissan Chemical Co., Ltd.).

  FIG. 4 is an enlarged view of a plan view on the first surface 21 side of the light collector 11 according to the embodiment of the present invention. The spherical body 14 protrudes from a substantially flat surface formed by the back surface 23 (not shown) of the reflective layer 13 on the first surface 21 of the light collector 11. FIG. 4 illustrates a configuration in which a part of the spherical body 14 protrudes from the coupling layer 12 laminated with the back surface 23 of the reflective layer 13 when the light collector includes the coupling layer 12. Due to such a configuration, the light collector 11 of the present invention can control the transmission and reflection of light, and can further improve the light collection efficiency.

  It is preferable that the spherical body 14 has a substantially uniform size (same size). When the spherical bodies 14 are substantially uniform in size and ideally arranged, as shown in FIG. 4, on the first surface 21 of the light collector 11, one spherical body is arranged so that six spherical bodies surround it. can do. When the spherical bodies 14 are arranged close to the closest packing as shown in FIG. 4, the light collector 11 is preferable because the transmittance of light incident from the first surface 21 side becomes high. In the present invention, that the plurality of spherical bodies 14 are substantially uniform in size (same size), the diameter of each of the plurality of spherical bodies 14 is measured with a microscope at 30 per observation field. When the average value and the standard deviation are obtained, it means that the obtained coefficient of variation (standard deviation / average value) is 0.5 or less. When calculating | requiring each diameter of the spherical body 14, an optical microscope and an electron microscope can be used suitably.

  In the light collector 11 of this embodiment, the reflecting surface 24 of the reflecting layer 13 on the second surface 22 side constitutes a substantially flat surface. The spherical body 14 penetrates the coupling layer 12 and the reflective layer 13. In other words, it is a structure in which a part of the spherical body 14 protrudes from a substantially flat surface formed by the reflecting surface 24 on the second surface 22. When the area of the substantially flat surface formed by the reflecting surface 24 of the second surface 22 is 100%, the area of the spherical body 14 occupying the second surface 22 may be in the range of 0.1% to 40%. For example, the light collector 11 of the present invention is preferable because it can properly collect and transmit light, and can appropriately reflect light. If the area is 0.1% or more, light incident from the first surface 21 of the light collector 11 can be sufficiently transmitted, and if it is 40% or less, it is preferable. Light incident on the surface 22 is preferable because it can be sufficiently reflected by the reflecting surface 24. In addition, the range of the said area observes the 2nd surface 22 side of the light-condensing plate 11 with a microscope, measures the area which the spherical body 14 occupies in the observation visual field, and the area which the reflection layer 13 occupies, respectively, and the reflection layer 13 It can be obtained by calculating the ratio of the area occupied by the spherical body 14 when the area occupied by 100 is 100%.

  FIG. 5 is an enlarged view of a plan view on the second surface 22 side of the light collector 11 according to the embodiment of the present invention. A part of the spherical body 14 protrudes from a substantially flat surface formed by the reflection surface 24 of the reflection layer 13 of the light collector 11.

  The present invention preferably has a tie layer 12. The bonding layer 12 is a layer in which the spherical body 14 protrudes and is laminated on the back surface 23 of the reflective layer 13. In other words, the bonding layer 12 is a layer that is stacked with the reflective layer 13 and bonds and holds the plurality of spherical bodies 14. Such a configuration is preferable because the bonding layer 12 bonds and holds the spherical body 14 more firmly, thereby increasing the strength of the light collector 11. The bonding layer 12 used for the light collector 11 which is a preferred embodiment of the present invention is preferably a material that has excellent adhesion to the reflective layer 13 and can maintain strong bonding with the plurality of spherical bodies 14.

  The coupling layer 12 may transmit light or may not transmit light.

  For the bonding layer 12, for example, various resins can be used, and a thermoplastic resin can be preferably used. Examples of the thermoplastic resin that can be suitably used for the bonding layer 12 include polyethylene, polypropylene, polyester, polyamide, poly (meth) acryl, polystyrene, polycarbonate, polylactic acid, ethylene vinyl alcohol copolymer, and polyurethane. It is done. If the bonding layer 12 is such a thermoplastic resin, it is preferable because the adhesiveness with the reflective layer 13 is excellent and the bonding with the spherical body 14 can be kept strong.

  For the bonding layer 12, a hot-melt adhesive, a light energy curable adhesive, or the like can also be suitably used.

  Specific examples of the thermoplastic resin that can be suitably used for the bonding layer 12 include Sumitomo Chemical Co., Ltd. trade name EXCELEN FXCX1001, Espolex SB2400, and Kuraray Co., Ltd. trade name EVAL E105B. Moreover, the hot melt adhesive which can be used suitably for the bonding layer 12 is a product name Tyforce HH-100 manufactured by DIC Corporation, and the light energy curable resin composition is a tie force Exp. DC-200 is mentioned respectively.

  The configuration excluding the spherical body 14 on the first surface 21 of the light collector 11, that is, the back surface 23 forms a substantially flat surface. In addition, when the light collector 11 includes the coupling layer 12 like the light collector 11 shown in FIG. 1, the surface of the coupling layer 12 also forms a substantially flat surface.

  The bonding layer 12 and the reflective layer 13 are provided with various additives for preventing deterioration of the layers represented by various dispersion aids represented by fillers, ultraviolet absorbers, and heat stabilizers for stabilization of production. It is possible to include.

  Moreover, when the light-condensing plate 11 of this invention has the coupling layer 12, it is preferable that the spherical body 14 performs various surface treatments on the surface. For example, the spherical body 14 can be firmly bonded to the bonding layer 12 by performing a surface treatment using a silane coupling agent or a fluorine-based additive. Furthermore, the magnitude | size which the spherical body 14 protrudes from the coupling layer 12 is controllable. That is, when the light collector 11 of the present invention has the bonding layer 12, by appropriately changing the surface treatment of the spherical body 14, the protruding distance from the reflective surface 24 of the spherical body 14 and the back surface 23 of the reflective layer 13 are reduced. The protruding distance can be easily controlled.

  In addition, the light collector 11 of the present invention can be provided with a layer other than the reflective layer 13, the spherical body 14, and the coupling layer 12, for example, a protective layer, as long as the light transmission and reflection performance is not significantly impaired. The protective layer is, for example, a transparent resin plate represented by an acrylic plate or a glass plate provided with a transparent adhesive layer. Using such a protective layer and the light collector 11 of the present invention in combination is preferable because the strength of the light collector is increased.

  Although there is no restriction | limiting in particular in the thickness of the light-condensing plate 11 of this invention, The range of 0.1 micrometer-1000 micrometers is suitable.

  The light collector 11 which is an embodiment of the present invention can be produced by the following method, for example. The manufacturing method is not limited to the following as long as the gist is not exceeded.

  Prepare a support such as polyethylene laminated paper. A thermoplastic resin laminated on the support, such as poly (meth) acryl, is heated and then layered, and then spherical bodies such as barium titanate glass beads are dispersed on the resin layer. The plurality of spherical bodies are uniformly spread and adhered to the resin layer in the spreading step. Further, the extra spherical body that does not adhere to the resin layer is sufficiently removed by using a brush or a gauge or blowing it with air or liquid before the next step. Next, the spherical body is appropriately selected in process conditions described later in the resin layer, and is embedded in the resin layer in an appropriate size. After the plurality of spherical bodies are buried, the atmospheric temperature of the process is further adjusted, and the plurality of spherical bodies are fixed to the resin layer. As described above, the bonding layer 12 in which the light-transmitting spherical bodies 14 are bonded is obtained. At this time, the atmospheric temperature of the process is preferably set to be equal to or higher than the softening temperature of the bonding layer 12. Moreover, adjustment of the atmospheric temperature of a process can be performed by using a hot air, infrared rays, far infrared rays, a microwave, a thermostat, and a planar heater. Further, if necessary, ultraviolet rays or the like can be used. Moreover, the magnitude | size with which the said spherical body embeds in the said resin layer can be appropriately controlled by performing a press. This pressing can be performed by, for example, a roller press or a flat plate press. The size of the spherical body embedded in the resin layer can be appropriately controlled by the heating method, temperature, heating time, pressing method, pressing force, and pressing time. Specifically, when the diameter of the spherical body is 100%, various conditions are appropriately controlled so that the degree of protrusion is about 40% to 60%. Furthermore, various embedding and pressing conditions are appropriately controlled so that the spherical body penetrates the resin layer and a part thereof is partially embedded in the support.

  After the support is peeled off, the reflecting layer 13 is provided on the side opposite to the side holding the spherical body 14 on the bonding layer 12 holding and bonding the spherical body 14, and an intermediate body of the light collector 11 is produced. In addition, in the bonding layer 12 holding the spherical body 14, the spherical body 14 penetrates the bonding layer that is a resin layer. Therefore, in the step of providing the reflective layer 13, the reflective layer 13 is laminated on the spherical body 14 as well as on the resin layer.

  The reflective layer 13 can be provided by vacuum-depositing a metal such as aluminum on the side opposite to the side where the intermediate spherical body 14 is held and bonded. Hereinafter, an example in which the reflective layer 13 is provided by vacuum deposition of aluminum will be described.

  Next, the aluminum layer laminated on the spherical body 14 protruding from the bonding layer 12 is removed.

  The step of removing the aluminum layer laminated on the spherical body 14 is not particularly limited, but can be performed by a known etching method such as plasma etching, reactive ion etching, chemical etching, or the like. At that time, by appropriately changing the conditions such as the atmospheric temperature and time, the aluminum layer laminated on the resin layer can be removed without removing the aluminum layer laminated on the resin layer.

  By the above method, the light collector 11 according to the embodiment of the present invention can be obtained.

  Next, a solar power generation module using the light collector 11 of the above embodiment will be described.

  FIG. 6 shows the structure of the cross section of the photovoltaic power generation module 41. The light collectors 11 c and 11 d are provided in the light receiving part 43 of the solar cell 42. At this time, the light collectors 11 c and 11 d include reflection layers 13 c and 13 d having reflection surfaces 24 c and 24 d facing the light receiving unit 43. In other words, the solar power generation module 41 includes the solar cell 42 having the light receiving unit 43 and the light collectors 11c and 11d. The reflective surface 24c of the light collector 11c and the reflective surface 24d of the light collector 11d are arranged to face each other. As shown in FIG. 6, the light receiving portion 43 of the solar cell 42 is installed between a pair of light collectors 11c and 11d. FIG. 6 illustrates an example in which the light receiving portion 43 of the solar cell 42 is installed substantially horizontally. In FIG. 6, the spherical bodies 14 included in the light collectors 11c and 11d are not shown.

  In FIG. 6, the light collectors 11 c and 11 d included in the solar power generation module 41 are installed at an angle of substantially 90 degrees with respect to the light receiving unit 43. The size ranges of the angles 51 and 52 formed by the light collectors 11c and 11d with respect to the light receiving unit 43 are preferably approximately 90 degrees. Thus, the condensing plate 11 of this invention shows the outstanding condensing efficiency by installing the reflective surface 24 of the condensing plate 11 so that it may mutually oppose. For example, when the light source is located at 31L in FIG. 6, in addition to the light that passes through the light collector 11c and irradiates the light receiver 43, and the light that directly irradiates the light receiver 43, the light receiver receives reflection of the light from the light collector 11d. The amount of light incident on the light receiving unit 43 from the light source 31 </ b> L to the solar power generation module 41 increases due to the contribution of the light irradiated to 43. Furthermore, even when the position of the light source is 31R, one light collector 11d transmits light from the other light collector 11c in addition to the light that passes through the light and irradiates the light receiver 43 and the light that directly irradiates the light receiver 43. The amount of light incident on the light receiving unit 43 to the solar power generation module 41 increases because the light irradiated to the reflected light receiving unit 43 contributes. Thus, since the light-condensing plate 11 of the present invention controls light transmission and reflection more efficiently, when it is used for the solar power generation module 41, it exhibits excellent light-condensing efficiency.

  When the light source incident on the photovoltaic power generation module 41 is the sun, the position of the light source changes with time. For example, in FIG. 6, the position of the light source 31 changes to 31L, 31M, 31R over time. In the light collector 11 of the present invention, the light collector 11 efficiently transmits and reflects light regardless of the position of the light source 31L, 31M, or 31R. The power generation amount of the module 41 increases.

  When the light source incident on the photovoltaic power generation module 41 is the sun, the position of the light source changes with time. Therefore, the conventional photovoltaic power generation module 41 may increase the amount of power generation by tracking the light source using an external power source and controlling the angle at which the light receiving unit 43 is inclined from the horizontal plane, for example.

  In addition, the photovoltaic power generation module 41 that does not track the light source may improve the power generation amount by inclining the angle between the light receiving unit of the light receiving unit 43 and the installation surface in consideration of the latitude of installation. For example, when the photovoltaic power generation module 41 is installed in Tokyo at 35 degrees north latitude, the light receiving unit 43 is directed to the south and takes about 23 degrees of the inclination of the earth axis to be about 58 degrees from the vertical plane (installed horizontally). Inclined about 32 degrees from the surface).

  Note that it is difficult to control the position of the light receiving unit 43 of the solar power generation module 41 so that the light source can be tracked using an external power source or to incline it from the horizontal plane due to restrictions on the installation conditions of the solar power generation module 41. There is a case. Therefore, for example, as described in Patent Document 1 (Japanese Patent Laid-Open No. 9-139518), various light receiving bodies (condensing devices and condensing plates) are used to increase the condensing efficiency and improve the power generation amount. May be.

  In a photoreceptor that combines a condensing plate having various prisms, light transmission and reflection are controlled by the prism, so the optical design of the prism is complicated, and it is difficult to form a prism for the condensing plate. There was a problem that it could not be obtained. Furthermore, it was necessary to change the prism shape design depending on the installation position (latitude) of the photovoltaic power generation module. In addition, it is virtually impossible for the sun to adapt the prism-shaped design to changing the altitude in the south and middle with each season. It is preferable that the light collector used in the solar power generation module has a simpler structure and exhibits high light collection efficiency regardless of the installation position (latitude) of the solar power generation module.

  The light collector 11 of the present invention has high light collection efficiency because light transmission and reflection are more efficiently controlled. Therefore, the solar power generation module 41 using this light collector 11 shows a power generation amount superior to that of the conventional one. Since the light collector 11 has a simple structure, it can be easily attached to the existing photovoltaic power generation module 41, and can be easily removed and replaced. Furthermore, since the light collector 11 of the present invention collects light using the spherical body 14, it can be installed in any installation position and in any season without changing the specifications depending on the installation position (latitude) of the photovoltaic power generation module. Also exhibits high light collection efficiency.

  FIG. 6 shows a case where there is only one pair of light collectors 11. For example, a light collector can be provided so as to surround the solar cell 42, and in that case, the light receiving efficiency of the solar power generation module 41 to the light receiving unit 43 can be further increased. Further, if the light collecting plate 11 is formed in a cylindrical shape and installed in the solar cell 42, for example, only one light collecting plate can be provided in the solar cell 42 in order to form a pair. That is, if at least a part of the reflecting surfaces of the reflecting plate of the light collecting plate are opposed to each other and there is a spherical body protruding from the reflecting surface, the light collecting efficiency can be improved as described above. By the way, although the solar cell 42 is normally configured by arranging a plurality of battery elements, a condensing plate is provided outside the plurality of arranged battery elements as compared with a case where a condensing plate is provided for each battery element. The case is preferred.

  As described above, according to the present invention, there is provided a light collector that can control the transmission and reflection of light and can further improve the light collection efficiency of the light receiving portion of the solar cell.

11, 11a, 11b, 11c, 11d ... Light collecting plate 12, 12a, 12b, 12c, 12d ... Coupling layer 13, 13a, 13b, 13c, 13d ... Reflective layer 14, 14a, 14b ... Spherical body 21, 21a, 21b ... 1st surface 22, 22a, 22b ... 2nd surface 23, 23c, 23d ... Back surface of reflective layer 24, 24c, 24d ... Reflection of reflective layer Surface 31, 31L, 31M, 31R ... Light source 32, 33, 34, 35 ... Light 41 ... Solar power generation module 42 ... Solar cell 43 ... Light receiving part 51, 52 ... Collection Angle formed by the optical plate with respect to the light receiving portion L: Projection distance of the spherical body from the back surface of the reflection layer R: Projection distance of the spherical body from the reflection surface of the reflection layer

Claims (5)

A light collector provided in the light receiving portion of the solar cell,
The light collector is
A reflective layer having a reflective surface facing the light receiving portion;
A plurality of light-transmitting spheres penetrating the reflective layer;
Have
The light collecting plate, wherein a protruding distance of the spherical body from the reflecting surface is smaller than a protruding distance from a back surface opposite to the reflecting surface. The condensing plate according to claim 1, further comprising a coupling layer that protrudes from the spherical body and is laminated on the back surface of the reflective layer. 3. The light collector according to claim 1, wherein the reflective layer is a metal layer. 4. The light collector according to claim 1, wherein a refractive index of the spherical body is in a range of 1.30 to 2.30. The solar power generation module which has the said light-condensing plate of any one of Claims 1-4, and the said solar cell.

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