WO2013183752A1

WO2013183752A1 - Solar cell module and photovoltaic power generation device

Info

Publication number: WO2013183752A1
Application number: PCT/JP2013/065790
Authority: WO
Inventors: 英臣由井; 前田　強
Original assignee: シャープ株式会社
Priority date: 2012-06-07
Filing date: 2013-06-07
Publication date: 2013-12-12
Also published as: JP2013254854A

Abstract

Provided is a solar cell module capable of efficiently generating electric power using external light. A solar cell module (1) is provided with: a light guide body (4) which allows fluorescent bodies (8) to absorb light entering from the outside and which propagates within the light guide body (4), fluorescent light radiated from the fluorescent bodies (8); and a solar cell element (6) which is disposed on a surface (4c) of the light guide body (4), the surface (4c) facing the light incident surface (4a) of the light guide body (4). The light guide body (4) is provided with: a facing region (4T) which faces the light receiving surface (6a) of the solar cell element (6); and a peripheral region (4F) which is located around the facing region (4T). The fluorescent bodies (8) are provided in a part of at least the peripheral region (4F) of the light guide body (4).

Description

Solar cell module and solar power generation device

The present invention relates to a solar cell module and a solar power generation device.

As a solar power generation device that installs a solar cell element on the end face of a light guide and makes light propagated through the light guide enter the solar cell element to generate power, the solar power generation device described in Patent Document 1 is Are known. The solar power generation device of Patent Document 1 includes a solar electronic element and a light guide disposed on the incident side of the light receiving surface. The light guide is made of a transparent plate having a facing region facing the light receiving surface of the solar cell element and a peripheral region of the peripheral portion thereof, and light incident on the facing region is transmitted through the light guide and passes through the solar electronic device. The light incident on the peripheral region propagates through the light guide and enters the solar cell element from the opposing region.

Japanese Patent Publication “Japanese Patent Laid-Open No. 2003-218378”

In the solar power generation device of Patent Document 1, an uneven surface is formed as a light introducing means on the surface of the peripheral region in order to take light incident on the peripheral region into the light guide. The light incident on the uneven surface is refracted or reflected by the uneven portion and introduced into the light guide. Of the light introduced into the light guide, the light incident on the light guide at an angle greater than the critical angle propagates through the light guide and enters the solar cell element. Since the reflected angle varies depending on the incident angle of the light to the light guide, when light enters the light guide at various angles such as scattered light, only a part of it can be used for power generation. Can not. Therefore, when light is scattered on the cloud and the light is incident on the light guide at various angles like a cloudy day, it is difficult to perform efficient power generation.

An object of the present invention is to provide a solar cell module and a solar power generation apparatus that can efficiently generate power using external light.

The solar cell module of the present invention absorbs light incident from the outside by a phosphor and propagates the fluorescence emitted from the phosphor inside, and a surface facing the light incident surface of the light guide A solar cell element installed on the light guide, the light guide body is provided with a facing region facing the light receiving surface of the solar cell element, and a peripheral region around the facing region, The phosphor is provided in at least a part of the peripheral region of the light guide.

The phosphor may not be provided in at least a part of the facing region of the light guide.

The phosphor may be provided in the facing region of the light guide, and the concentration of the phosphor in the facing region may be lower than the concentration of the phosphor in the peripheral region.

The thickness of the peripheral region of the light guide may increase as it approaches the solar cell element.

A plurality of the solar cell elements may be installed on a surface of the light guide that faces the light incident surface.

A reflection layer that reflects the fluorescence may be provided on a portion of the surface of the light guide opposite to the light incident surface other than the portion where the solar cell element is installed.

A reflection layer that reflects the fluorescence may be provided on an end surface adjacent to the light incident surface of the light guide.

The light guide may be formed by laminating a layer containing the phosphor and a layer not containing the phosphor.

The light guide may include a plurality of types of phosphors as the phosphor.

The spectral sensitivity of the solar cell element at the peak wavelength of the emission spectrum of the phosphor having the largest emission spectrum peak wavelength among the plurality of types of phosphors is that of the solar cell element at the peak wavelength of the emission spectrum of the other phosphors. It may be larger than the spectral sensitivity.

When viewed from the normal direction of the light incident surface of the light guide, the area of the peripheral region of the light guide that is provided with the phosphor is the area of the counter region of the light guide. It may be larger than the area of the region where the phosphor is not provided.

The solar power generation device of the present invention includes the solar cell module of the present invention.

According to the present invention, it is possible to provide a solar cell module and a solar power generation device that can efficiently generate power using external light.

It is the top view and sectional drawing of the solar cell module of 1st Embodiment. It is a figure explaining the effect | action of a solar cell module. It is a figure which shows the relationship between solar radiation intensity and the conversion efficiency of a solar cell element. It is sectional drawing of the solar cell module of 2nd Embodiment. It is a figure explaining the effect | action of a solar cell module. It is the top view and sectional drawing of the solar cell module of 3rd Embodiment. It is a figure explaining the effect | action of a solar cell module. It is sectional drawing of the solar cell module of 4th Embodiment. It is the top view and sectional drawing of the solar cell module of 5th Embodiment. It is sectional drawing of the solar cell module of 6th Embodiment. It is sectional drawing of the solar cell module of 7th Embodiment. It is sectional drawing of the solar cell module of 8th Embodiment. It is sectional drawing of the solar cell module of 9th Embodiment. It is sectional drawing of the solar cell module of 10th Embodiment. It is sectional drawing of the solar cell module of 11th Embodiment. It is sectional drawing of the light guide used for the solar cell module of 12th Embodiment. It is a figure which shows the absorption characteristic of fluorescent substance. It is a figure which shows the absorption characteristic of fluorescent substance. It is a figure which shows the light emission characteristic of fluorescent substance. It is a figure which shows the light emission characteristic of fluorescent substance. It is explanatory drawing of a Forster mechanism. It is explanatory drawing of a Forster mechanism. It is a figure which shows the spectral sensitivity curve of an amorphous silicon solar cell with the emission spectrum of 1st fluorescent substance, the emission spectrum of 2nd fluorescent substance, and the emission spectrum of 3rd fluorescent substance. It is sectional drawing of the solar cell module of 13th Embodiment. It is sectional drawing of the solar cell module of 14th Embodiment. It is a schematic block diagram of a solar power generation device.

[First Embodiment]
Fig.1 (a) is a top view of the solar cell module 1 of 1st Embodiment. FIG. 1B is a cross-sectional view of the solar cell module 1.

The solar cell module 1 includes a light guide 4 and solar cell elements 6 installed on a surface 4 b facing the light incident surface 4 a of the light guide 4.

The light guide 4 is a substantially rectangular plate member having a constant thickness. The 1st main surface 4a of the light guide 4 is a light-incidence surface in which light enters from the exterior, and the part in which the solar cell element 6 is installed among the 2nd main surfaces 4b of the light guide 4 is a solar cell. This is a light emission surface 4 c that emits light to the element 6.

The light guide 4 is obtained by dispersing the optical functional material 8 in a base material (transparent substrate) made of a highly transparent organic material or inorganic material such as acrylic resin, polycarbonate resin, or glass. Examples of the optical functional material 8 include a phosphor that absorbs ultraviolet light or visible light and emits visible light or infrared light. Note that visible light is light in a wavelength region of 380 nm to 750 nm, ultraviolet light is light in a wavelength region less than 380 nm, and infrared light is light in a wavelength region larger than 750 nm.

In the case of this embodiment, PMMA is used as the base material of the light guide 4, and Lumogen® Red® 305 (trade name) manufactured by BASF is used as the optical functional material. Lumogen Red 305 (trade name) is a phosphor having an emission spectrum peak wavelength at 578 nm. The light guide 4 is provided with only one type of phosphor as the optical functional material 8, but a plurality of types of phosphors are provided in the light guide 4 in order to absorb light of a wide range of wavelengths. May be.

The light guide 4 includes a facing region 4T facing the light receiving surface 6a of the solar cell element 6, and a peripheral region 4F around the facing region 4T. An optical functional material 8 is provided in at least a part of the peripheral region 4F.

In the case of this embodiment, the optical functional material 8 is provided in the entire peripheral region 4F, and the optical functional material 8 is not provided at all in the facing region 4T, but the configuration of the light guide 4 is not limited to this. For example, the optical functional material 8 may be provided only in a part of the peripheral region 4F, or the optical functional material 8 may be provided in a part of the facing region 4T.

The solar cell element 6 is disposed with the light receiving surface facing the light exit surface 4 c of the light guide 4. The solar cell element 6 is preferably optically bonded to the light emitting surface 4c with a transparent adhesive. As the solar cell element 6, a known solar cell such as a silicon solar cell, a compound solar cell, or an organic solar cell can be used.

As the solar cell element 6, one having a spectral sensitivity corresponding to the spectrum of light incident from the light exit surface 4c is selected. For example, when viewed from the normal direction of the light incident surface 4 a of the light guide 4, the area of the peripheral region 4 F of the light guide 4 where the optical functional material 8 is provided is equal to the opposing region 4 T of the light guide 4. If the area is larger than the area of the region where the optical functional material 8 is not provided, the amount of light that passes through the facing region 4T and directly enters the solar cell element 6 is changed from the peripheral region 4F to the solar cell element 6. Increasing the amount of incident fluorescence. Therefore, in this case, a solar cell having a spectral sensitivity suitable for the fluorescence spectrum is selected. In this case, the solar cell element 6 only needs to have a high spectral sensitivity with respect to light in a narrow wavelength region, so even if a tandem solar cell is used, the number of semiconductor layers to be manufactured is reduced. Can be configured easily.

FIG. 2 is a diagram for explaining the operation of the solar cell module 1.

The light L incident on the facing region 4T of the light guide 4 passes through the facing region 4T and enters the solar cell element 6. Since the optical functional material 8 is not included in the facing region 4T, the light L is incident on the solar cell element 6 without being absorbed by the optical functional material 8. Therefore, the light L incident on the facing region 4T can be efficiently used for power generation.

The light L incident on the peripheral region 4F of the light guide 4 excites the optical functional material 8. The light L1 (fluorescence) emitted from the optical functional material 8 propagates through the light guide 4 and enters the solar cell element 6 from the light exit surface 4c. Since the optical functional material 8 absorbs light incident from all directions, not only light incident perpendicularly to the peripheral region 4F but also light incident obliquely can be used for power generation. Therefore, even when the incident angle of the light L is different depending on the time zone, such as daytime and evening, or when the incident angle of the light L is irregular because the light is scattered by the clouds, efficient power generation is possible. Become.

FIG. 3 is a diagram showing the relationship between the solar radiation intensity and the conversion efficiency of the solar cell element 6. In FIG. 3, the solid line indicates the conversion efficiency of the solar cell element 6 when the peripheral region 4F is provided around the facing region 4T. A dotted line indicates the conversion efficiency of the solar cell element 6 when the peripheral region 4F is not provided around the facing region 4T.

As shown by a dotted line, the conversion efficiency of the solar cell element 6 shows a substantially constant value in a region where the solar radiation intensity is strong, and greatly decreases as the solar radiation intensity decreases in a region where the solar radiation intensity is weak. Therefore, when only the light directly incident on the solar cell element 6 is used for power generation without providing the peripheral region 4F, the intensity of the light incident on the solar cell element 6 does not increase so much, so the conversion efficiency varies depending on the solar radiation intensity. It becomes easy.

On the other hand, as shown by the solid line, when the peripheral region 4F is provided, the intensity of light incident on the solar cell element 6 is increased by the intensity of the light collected from the peripheral region 4F. The conversion efficiency of the element 6 is less likely to vary depending on the solar radiation intensity. Therefore, efficient power generation can be performed even on a cloudy day or dusk.

As described above, in the solar cell module 1 of the present embodiment, the peripheral region 4F is provided around the solar cell element 6, and the light L incident on the peripheral region 4F is converted into fluorescence and incident on the solar cell element 6. Yes. Therefore, not only the light L directly incident on the solar cell element 6 but also the light incident on the peripheral portion of the solar cell element 6 can be used for power generation. Further, since the optical functional material 8 absorbs the light L incident from all directions, even when light scattered by the clouds enters the light guide 4 as in a cloudy day, efficient power generation can be performed. It becomes possible.

In this embodiment, the light guide 4 is a plate-like member having a constant thickness, but the configuration of the light guide 4 is not limited to this. For example, a film-like member having a constant thickness, or a plate-like or film-like member having a partially different thickness may be used as the light guide 4. Moreover, in this embodiment, although the planar shape of the light guide 4 was made into the substantially rectangular shape, the structure of the light guide 4 is not restricted to this. For example, a plate-like or film-like member having an arbitrary shape other than a rectangle such as a circle, an ellipse, or a polygon may be used as the light guide 4.

[Second Embodiment]
FIG. 4 is a cross-sectional view of the solar cell module 10 of the second embodiment.

This embodiment is different from the first embodiment in that the thickness of the light guide 5 in the peripheral region 5F increases as the solar cell element 6 is approached. Note that the thickness of the light guide 5 in the facing region 5T is constant.

In the case of the present embodiment, the second main surface 5b of the light guide 5 excluding the light exit surface 5c is inclined at a constant angle with respect to the light incident surface 5a. It is not limited. For example, a part or all of the second main surface 5b of the light guide 5 except the light emission surface 5c may be curved.

FIG. 5B is a diagram for explaining the operation of the solar cell module 10. FIG. 5A is a diagram for explaining the operation of the solar cell module when the thickness of the light guide is constant (when the light guide 4 of the first embodiment is used) as a comparative example.

As shown in FIG. 5A, the light incident on the peripheral region 4F of the light guide 4 is absorbed by the optical functional material 8 and converted into light L1 (fluorescence). The light L1 is emitted in all directions, but the light L1 incident on the main surface of the light guide 4 (the second main surface 4b in FIG. 5A) at an angle smaller than the critical angle is not totally reflected. Leaks out of the light guide 4.

As shown in FIG. 5B, the light guide 5 is not a flat plate, but is inclined toward the second main surface 5b side so as to become thicker toward the solar cell element installation portion (opposite region). Then, most of the fluorescence emitted from the optical functional material 8 to the solar cell element side satisfies the total reflection condition. Therefore, more light can be made incident on the solar cell element than when the light guide is formed in a flat plate shape.

As described above, in the solar cell module 10 of the present embodiment, the solar cell element 6 efficiently emits the light L1 emitted from the optical functional material 8 by the inclined surface provided on the second main surface 5b of the light guide 5. Can be made incident. Therefore, efficient power generation becomes possible.

[Third Embodiment]
FIG. 6A is a plan view of the solar cell module 11 of the third embodiment. FIG. 6B is a cross-sectional view of the solar cell module 11.

In the present embodiment, the difference from the first embodiment is that a plurality of solar cell elements 6 are installed on a surface (second main surface 4b) facing the light incident surface 4a of the light guide 4.

In the case of this embodiment, for example, the four solar cell elements 6 are arranged in a square lattice shape when viewed from the light incident surface 4a side of the light guide 4, but the number and arrangement of the solar cell elements 6 are limited to this. Not. For example, five or more solar cell elements 6 may be arranged in a rectangular lattice shape, an oblique lattice shape, or a hexagonal lattice shape when viewed from the light incident surface 4 a side of the light guide 4. Further, the pitch of the solar cell elements 6 (the distance between the centers of two adjacent solar cell elements 6) may be different between the central portion and the peripheral portion of the light guide 5.

FIG. 7A and FIG. 7B are diagrams for explaining the operation of the solar cell module 11.

The light L1 (fluorescence) emitted from the optical functional material 8 travels in all directions. Since a plurality of solar cell elements 6 are arranged in the light guide 4, the light L 1 enters one of the solar cell elements 6 without propagating a long distance. When the light L1 propagates through the light guide 4 for a long distance, a part of the light L1 is lost due to absorption by the base material of the light guide 4 and self-absorption by the optical functional material 8. However, if the propagation distance of the light L1 is shortened as in the present embodiment, such loss can be reduced, and efficient power generation is possible.

As described above, according to the solar cell module 11 of this embodiment, the solar cell module capable of reducing the loss of the light L1 when the light L1 propagates through the light guide 4 and performing efficient power generation. Is provided.

[Fourth Embodiment]
FIG. 8 is a cross-sectional view of the solar cell module 12 of the fourth embodiment.

In this embodiment, the difference from the third embodiment is that the thickness of the light guide 13 in the peripheral region 13F increases as the solar cell element 6 is approached. Note that the thickness of the light guide 13 in the facing region 13T is constant.

In the case of the present embodiment, the second main surface 13b of the light guide body 13 excluding the light exit surface 13c is inclined at a constant angle with respect to the light incident surface 13a at a portion located in the vicinity of the solar cell element 6. The portion located in the middle between the two adjacent solar cell elements 6 is parallel to the light incident surface 13a, but the configuration of the light guide 13 is not limited to this. For example, a part or all of the second main surface 13b of the light guide 13 except the light emission surface 13c may be curved.

In the solar cell module 12 of this embodiment, the light L1 emitted from the optical functional material 8 can be efficiently incident on the solar cell element 6 by the inclined surface provided on the second main surface 13b of the light guide 13. it can. Therefore, efficient power generation becomes possible.

[Fifth Embodiment]
Fig.9 (a) is a top view of the solar cell module 14 of 5th Embodiment. FIG. 9B is a cross-sectional view of the solar cell module 14.

This embodiment differs from the first embodiment in that a reflective layer 9 that reflects light L1 (fluorescence) emitted from the optical functional material 8 is provided on the end surface 4d adjacent to the light incident surface 4a of the light guide 4. This is the point.

In the case of this embodiment, the reflective layer 9 is provided on all four end faces 4d of the light guide 4. The reflective layer 9 may be provided in direct contact with the end surface 4d without an air layer, or may be provided with an air layer on the end surface 4d.

As the reflective layer 9, a reflective layer made of a metal film such as silver or aluminum, or a reflective layer made of a dielectric multilayer film such as an ESR (Enhanced Specular Reflector) reflective film (manufactured by 3M) can be used. The reflection layer 9 may be a specular reflection layer that specularly reflects incident light, or may be a scattering reflection layer that scatters and reflects incident light. As the scattering reflection layer, micro-fired PET (polyethylene terephthalate) (manufactured by Furukawa Electric) can be used.

The reflection layer 9 reflects the light L1 traveling from the inside of the light guide 4 toward the outside of the light guide 4 toward the inside of the light guide 4. Therefore, the light L1 leaking outside from the end face 4d of the light guide 4 can be reduced, and the light L1 can be efficiently incident on the solar cell element 6.

As described above, according to the solar cell module 14 of the present embodiment, a solar cell module capable of reducing the light L1 leaking from the end face 4d of the light guide 4 and efficiently generating power is provided.

[Sixth Embodiment]
FIG. 10 is a cross-sectional view of the solar cell module 15 of the sixth embodiment.

In this embodiment, the difference from the first embodiment is that a portion (light emission surface 4c) where the solar cell element 6 is installed in a surface (second main surface 4b) facing the light incident surface 4a of the light guide 4. In other parts, a reflective layer 7 for reflecting the light L1 (fluorescence) emitted from the optical functional material 8 is provided.

In the case of the present embodiment, the reflective layer 7 is provided on the entire surface of the second main surface 4b other than the light exit surface 4c of the light guide 4. The reflective layer 7 may be provided in direct contact with the second main surface 4b without an air layer, or may be provided on the second main surface 4b with an air layer interposed therebetween.

As the reflective layer 7, a reflective layer made of a metal film such as silver or aluminum, or a reflective layer made of a dielectric multilayer film such as an ESR (Enhanced Specular Reflector) reflective film (manufactured by 3M) can be used. The reflection layer 7 may be a specular reflection layer that specularly reflects incident light, or a scattering reflection layer that scatters and reflects incident light. When a scattering reflection layer is used for the reflection layer 7, the amount of light that goes directly in the direction of the solar cell element 6 increases, so that the light collection efficiency to the solar cell element 6 increases and the amount of power generation increases. In addition, since the reflected light is scattered, changes in the amount of power generation with time and season are averaged. As the scattering reflection layer, micro-fired PET (polyethylene terephthalate) (manufactured by Furukawa Electric) can be used.

The reflection layer 7 reflects the light L 1 traveling from the inside of the light guide 4 toward the outside of the light guide 4 toward the inside of the light guide 4. Therefore, the light L1 leaking outside from the second main surface 4b of the light guide 4 can be reduced, and the light L1 can be efficiently incident on the solar cell element 6.

The reflection layer 7 reflects the light L, which is incident from the light incident surface 4 a but is not absorbed by the optical functional material 8 and is emitted from the second main surface 4 b, toward the inside of the light guide 4. Therefore, both the light L directly incident from the light incident surface 4 a and the light L reflected by the reflective layer 7 can be absorbed by the optical functional material 8. Therefore, even if the concentration of the optical functional material 8 is reduced, the light L incident from the light incident surface 4a can be efficiently converted into light L1 (fluorescence).

As the optical functional material 8 used for the light guide 4, a material having a high fluorescence quantum yield is desirable. However, since the optical functional material 8 having a high fluorescence quantum yield has a small Stokes shift, it absorbs the light L 1 emitted by itself. This causes the problem of self-absorption. Therefore, the loss of the light L1 due to self absorption increases as the concentration of the contained optical functional material 8 increases.

In the present embodiment, since the reflective layer 7 is provided on the second main surface 4b, the light L can be sufficiently absorbed even if the concentration of the optical functional material 8 contained in the light guide 4 is reduced. it can. By reducing the concentration of the optical functional material 8, the loss of the light L1 due to self-absorption is reduced, and efficient power generation becomes possible.

As described above, according to the solar cell module 14 of the present embodiment, the light L1 leaking from the second main surface 4b of the light guide 4 is reduced by the reflective layer 7, and self-absorption by the optical functional material is suppressed. Since it is possible, efficient power generation becomes possible.

[Seventh Embodiment]
FIG. 11 is a cross-sectional view of the solar cell module 16 of the seventh embodiment.

This embodiment is different from the sixth embodiment in that the thickness of the light guide 5 in the peripheral region 5F increases as the solar cell element 6 is approached.

In the solar cell module 16 of the present embodiment, the light L1 emitted from the optical functional material 8 can be efficiently incident on the solar cell element 6 by the inclined surface provided on the second main surface 5b of the light guide 5. it can. Therefore, efficient power generation becomes possible.

[Eighth Embodiment]
FIG. 12 is a cross-sectional view of the solar cell module 17 according to the eighth embodiment.

This embodiment is different from the first embodiment in that the light guide 20 is formed by laminating a first layer 19 including an optical functional material and a second layer 18 not including the optical functional material. It is a point.

In the case of this embodiment, the first layer 19 is a fluorescent film that includes a transparent base material that does not contain a phosphor and an optical functional material dispersed inside the transparent base material. As the optical functional material, the same one as in the first embodiment (one that converts light incident from the outside of the light guide 20 into fluorescence) is used. The second layer 18 is a plate-like transparent light guide made of a highly transparent organic material or inorganic material such as acrylic resin, polycarbonate resin, or glass.

The transparent base material and the transparent light guide are transparent layers that do not contain an optical functional material. Even those made of a material that is not transparent can be used as a transparent substrate and a transparent light guide.

The first layer 19 and the second layer 18 are detachably bonded with an adhesive. The first layer 19 is peeled off from the second layer 18 and replaced when damage, deterioration, or adhesion of foreign matter (such as dust or bird droppings) occurs.

The first layer 19 and the second layer 18 are arranged in this order from the outside light incident side. The surface of the first layer 19 opposite to the second layer 18 is the first main surface 20a of the light guide 20, and the main surface of the second layer 18 opposite to the first layer 19 is conductive. This is the second main surface of the light body 20. The solar cell element 6 is installed on the second main surface 20 b of the light guide 20. The first main surface 20a of the light guide 20 is a light incident surface on which light enters from the outside, and the portion of the second main surface 20b of the light guide 20 where the solar cell element 6 is installed is a solar cell. This is a light emission surface 20 c that emits light to the element 6.

The light guide 20 includes a facing region 20T facing the light receiving surface of the solar cell element 6, and a peripheral region 20F around the facing region 20T. The first layer 19 is provided in at least a part of the peripheral region 20F.

In the case of the present embodiment, the first layer 19 has an opening having the same size as the light receiving surface of the solar cell element 6, and the first layer 19 is provided in the entire peripheral region 20F. The configuration of the first layer 19 is not limited to this. For example, the opening of the first layer 19 may be made larger than the light receiving surface of the solar cell element 6 or may be made smaller than the light receiving surface of the solar cell element 6.

The light (fluorescence) emitted from the first layer 19 propagates through the first layer 19 and the second layer 18 and enters the solar cell element 6 from the light exit surface 20c. Since light enters the solar cell element 6 through both the first layer 19 containing the optical functional material and the second layer 18 not containing the optical functional material, the entire light guide is a layer containing the optical functional material. Compared with the case where it is formed by, self-absorption by the optical functional material can be suppressed.

The light incident on the facing region 20T of the light guide 20 passes through the opening of the first layer 19 and the second layer 18 and enters the solar cell element 6. Since the opto-region 20T does not contain the optical functional material, the light incident from the outside enters the solar cell element 6 without being absorbed by the optical functional material. Therefore, the light incident on the facing region 20T can be efficiently used for power generation.

As described above, according to the solar cell module 17 of the present embodiment, since the light guide 20 is formed by the two-layer structure of the first layer 19 and the second layer 18, the light guide 20 is made light. Therefore, it is possible to reduce the loss of light when propagating and to efficiently generate power.

In addition, since the first layer 18 and the second layer 19 are joined so as to be able to chestnuts depending on the adhesive, the first layer 19 is damaged, deteriorated, or has adhered foreign matter (such as dust or bird droppings). When the power generation efficiency is reduced, only the first layer 19 can be peeled off from the second layer 18 and replaced. Therefore, the maintenance cost can be reduced as compared with the case where the entire light guide is replaced.

[Ninth Embodiment]
FIG. 13 is a cross-sectional view of the solar cell module 21 of the ninth embodiment.

This embodiment is different from the eighth embodiment in that the light guide 25 includes a first layer 24 that does not include an optical functional material, a second layer 23 that includes an optical functional material, and a first layer that does not include an optical functional material. The third layer 22 is laminated.

In the case of this embodiment, by applying a solution in which an optical functional material is dispersed in a toluene solvent to a transparent PMMA substrate masking the installation portion of the solar cell element, the above layered structure (first layer 24, A second layer 23 and a third layer 22) are formed. The optical functional material in the solution penetrates into the PMMA substrate, and selectively forms a layer (second layer 23) of the optical functional material in a specific region in the thickness direction of the PMMA substrate. Transparent layers (the first layer 24 and the third layer 22) containing almost no optical functional material are formed above and below the optical functional material layer.

The first layer 24, the second layer 23, and the third layer 22 are arranged in this order from the outside light incident side. The surface of the first layer 24 opposite to the second layer 23 is the first main surface 25a of the light guide 25, and the main surface of the third layer 22 opposite to the second layer 23 is conductive. This is the second main surface of the light body 25. The solar cell element 6 is installed on the second main surface 25 b of the light guide 25. The 1st main surface 25a of the light guide 25 is a light-incidence surface in which light injects from the outside, and the part in which the solar cell element 6 is installed among the 2nd main surfaces 25b of the light guide 25 is a solar cell. This is a light emission surface 25 c that emits light to the element 6.

The light guide 25 includes a facing region 25T facing the light receiving surface of the solar cell element 6, and a peripheral region 25F around the facing region 25T. The second layer 23 is provided in at least a part of the peripheral region 25F.

In the case of the present embodiment, the second layer 23 has an opening having the same size as the light receiving surface of the solar cell element 6, and the second layer 23 is provided in the entire peripheral region 25F. The configuration of the second layer 23 is not limited to this. For example, the opening of the second layer 23 may be made larger than the light receiving surface of the solar cell element 6 or may be made smaller than the light receiving surface of the solar cell element 6.

The light (fluorescence) emitted from the second layer 23 propagates through the first layer 24, the second layer 23, and the third layer 22, and enters the solar cell element 6 from the light exit surface 25c. . Since light enters the solar cell element 6 through both the second layer 23 containing the optical functional material and the first layer 24 and the third layer 22 not containing the optical functional material, the entire light guide is Self-absorption by the optical functional material can be suppressed as compared with the case where the optical functional material is used.

The light incident on the facing region 25T of the light guide 25 passes through the first layer 24, the opening of the second layer 23, and the third layer 22 and enters the solar cell element 6. Since the optical functional material is not included in the facing region 25T, light incident from the outside enters the solar cell element 6 without being absorbed by the optical functional material. Therefore, the light incident on the facing region 25T can be efficiently used for power generation.

As described above, according to the solar cell module 21 of the present embodiment, the light guide 25 is formed by the three-layer structure of the first layer 24, the second layer 23, and the third layer 22, Light loss when light propagates through the light guide 25 can be reduced, and efficient power generation can be performed.

[Tenth embodiment]
FIG. 14 is a cross-sectional view of the solar cell module 26 of the tenth embodiment.

In this embodiment, the tail point of the eighth embodiment is that the light guide 29 is formed by laminating the first layer 27 containing the optical functional material and the second layer 28 not containing the optical functional material. The light (fluorescence) radiated from the optical functional material is reflected on the end face and the end face adjacent to the light incident face 29a of the light guide 29 (end faces of the first layer 27 and the second layer 28). The point is that a reflective layer 9 is provided.

The first layer 27 has the same configuration as the first layer 19 of the eighth embodiment, and the second layer 28 has the same configuration as the second layer 18 of the eighth embodiment. This embodiment is different from the eighth embodiment in that the second layer 28 and the first layer 27 are arranged in this order from the external light incident side.

The first layer 27 and the second layer 28 are detachably bonded with an adhesive. The first layer 27 is peeled off from the second layer 28 and exchanged when damage, deterioration, or adhesion of foreign matter (such as dust or bird droppings) occurs.

The surface of the second layer 28 opposite to the first layer 27 is a first main surface 29a of the light guide 29, and the main surface of the first layer 27 opposite to the second layer 28 and the first surface 27a. Of the main surface of the second layer 28 facing the light incident surface 29 a, the portion exposed from the first layer 27 is the second main surface of the light guide 29. The solar cell element 6 is installed on the second main surface 29 b of the light guide 29. The first main surface 29a of the light guide 29 is a light incident surface on which light enters from the outside, and the portion of the second main surface 29b of the light guide 29 where the solar cell element 6 is installed is a solar cell. This is a light emission surface 29 c that emits light to the element 6.

The light guide 29 includes a facing area 29T facing the light receiving surface of the solar cell element 6, and a peripheral area 29F around the facing area 29T. The first layer 27 is provided in at least a part of the peripheral region 29F.

In the present embodiment, the first layer 27 has an opening having the same size as the light receiving surface of the solar cell element 6, and the first layer 27 is provided in the entire peripheral region 29 F. The configuration of the first layer 27 is not limited to this. For example, the opening of the first layer 27 may be made larger than the light receiving surface of the solar cell element 6 or may be made smaller than the light receiving surface of the solar cell element 6.

The light (fluorescence) emitted from the first layer 27 propagates through the first layer 27 and the second layer 28 and enters the solar cell element 6 from the light exit surface 29c. Since light enters the solar cell element 6 through both the first layer 27 containing the optical functional material and the second layer 28 not containing the optical functional material, the entire light guide is a layer containing the optical functional material. Compared with the case where it is formed by, self-absorption by the optical functional material can be suppressed.

The light incident on the facing region 29T of the light guide 29 passes through the openings of the second layer 28 and the first layer 27 and enters the solar cell element 6. Since the optical functional material is not included in the facing region 29T, the light incident from the outside enters the solar cell element 6 without being absorbed by the optical functional material. Therefore, the light incident on the facing region 29T can be efficiently used for power generation.

The reflective layer 9 described in the fifth embodiment is provided on the four end faces of the light guide 29. The reflective layer 9 may be provided in direct contact with the end face of the light guide 29 without an air layer, or may be provided on the end face of the light guide 29 with an air layer interposed therebetween. The reflective layer 9 reflects light traveling from the inside of the light guide 29 toward the outside of the light guide 29 toward the inside of the light guide 29. Therefore, light leaking out from the end face of the light guide 29 can be reduced, and light can be efficiently incident on the solar cell element 6.

As described above, according to the solar cell module 26 of the present embodiment, since the light guide 29 is formed by the two-layer structure of the first layer 27 and the second layer 28, the light is transmitted through the light guide 29. Light loss during propagation can be reduced, and efficient power generation can be performed. Moreover, since the reflective layer 9 is provided on the end surface of the light guide 29, light leaking from the end surface of the light guide 29 is reduced, and more efficient power generation is possible.

[Eleventh embodiment]
FIG. 15 is a cross-sectional view of the solar cell module 30 of the eleventh embodiment.

In the present embodiment, the difference from the tenth embodiment is that a portion (light emission surface 33c) where the solar cell element 6 is installed in the surface (second main surface 33b) of the light guide 33 that faces the light incident surface 33a. In other parts, a reflective layer 7 for reflecting light (fluorescence) emitted from the optical functional material is provided. In FIG. 15, the reflective layer is not provided on the end surface of the light guide 33, but the same reflective layer 9 as in the tenth embodiment may be provided on the end surface of the light guide 33.

The light guide 33 is formed by laminating a first layer 31 containing an optical functional material and a second layer 32 not containing the optical functional material. The first layer 31 has the same configuration as the first layer 27 of the tenth embodiment, and the second layer 32 has the same configuration as the second layer 28 of the tenth embodiment.

The first layer 31 and the second layer 32 are detachably bonded with an adhesive. The first layer 31 is peeled off from the second layer 32 and replaced when damage, deterioration, or adhesion of foreign matter (such as dust or bird droppings) occurs.

The surface of the second layer 32 opposite to the first layer 31 is the first main surface 33a of the light guide 33, the main surface of the first layer 31 opposite to the second layer 32, and the first surface. Of the main surface of the second layer 32 facing the light incident surface 33 a, the portion exposed from the first layer 31 is the second main surface of the light guide 33. The solar cell element 6 is installed on the second main surface 33 b of the light guide 33. The first main surface 33a of the light guide 33 is a light incident surface on which light enters from the outside, and the portion of the second main surface 33b of the light guide 33 where the solar cell element 6 is installed is a solar cell. This is a light emission surface 33 c that emits light to the element 6.

The light guide 33 includes a facing region 33T facing the light receiving surface of the solar cell element 6, and a peripheral region 33F around the facing region 33T. The first layer 31 is provided in at least a part of the peripheral region 33F.

In the case of the present embodiment, the first layer 31 has an opening having the same size as the light receiving surface of the solar cell element 6, and the first layer 31 is provided in the entire peripheral region 33F. The configuration of the first layer 31 is not limited to this. For example, the opening of the first layer 31 may be made larger than the light receiving surface of the solar cell element 6 or may be made smaller than the light receiving surface of the solar cell element 6.

The reflective layer 7 described in the sixth embodiment is provided in a region other than the light emission surface 33c in the second main surface 33b of the light guide 33. The reflective layer 7 may be provided in direct contact with the second main surface 33b of the light guide 33 without using an air layer, or provided on the second main surface 33b of the light guide 33 with an air layer interposed therebetween. It may be done.

The reflection layer 7 reflects light traveling from the inside of the light guide 33 toward the outside of the light guide 33 toward the inside of the light guide 33. Therefore, light leaking out from the end face of the light guide 33 can be reduced, and light can be efficiently incident on the solar cell element 6.

In addition, the reflective layer 7 directs the light that has entered the light incident surface 33 a but is not absorbed by the optical functional material included in the first layer 31 and is emitted from the second main surface 33 b toward the inside of the light guide 33. reflect. Therefore, both the light directly incident from the light incident surface 33a and the light reflected by the reflective layer 7 can be absorbed by the optical functional material. Therefore, even if the concentration of the optical functional material is reduced, the light incident from the light incident surface 33a can be efficiently converted into fluorescence. By reducing the concentration of the optical functional material, light loss due to self-absorption is reduced, and efficient power generation becomes possible.

As described above, according to the solar cell module 30 of the present embodiment, the light guide 33 is formed by the two-layer structure of the first layer 31 and the second layer 32. Therefore, it is possible to reduce the loss of light when propagating and to efficiently generate power. Further, light leaking from the second main surface 33b of the light guide 33 can be reduced by the reflective layer 7, and self-absorption by the optical functional material can be suppressed, so that more efficient power generation is possible.

[Twelfth embodiment]
FIG. 16 is a cross-sectional view of the light guide 36 used in the solar cell module 34 of the twelfth embodiment.

This embodiment is different from the eighth embodiment in that the light guide 36 is provided with a plurality of types of optical functional materials as optical functional materials.

The light guide 36 is formed by laminating a first layer 35 containing an optical functional material and a second layer 18 not containing the optical functional material. In the case of this embodiment, the first layer 35 has a plurality of types of phosphors having different absorption wavelength ranges as optical functional materials (for example, the first phosphor 8a, the second phosphor 8b, and the third phosphor in FIG. 16). The body 8c) is dispersed. The first phosphor 8a absorbs ultraviolet light and emits blue fluorescence, the second phosphor 8b absorbs blue light and emits green fluorescence, and the third phosphor 8c emits green light. Absorbs and emits red fluorescence. The base material on which the optical functional material is dispersed is the same as that described in the eighth embodiment.

The first layer 35 and the second layer 18 are detachably bonded with an adhesive. The first layer 35 is peeled off from the second layer 18 and replaced when damage, deterioration, or adhesion of foreign matter (such as dust or bird droppings) occurs.

The first layer 35 and the second layer 18 are arranged in this order from the outside light incident side. The surface of the first layer 35 opposite to the second layer 18 is the first main surface 36a of the light guide 36, and the main surface of the second layer 18 opposite to the first layer 35 is conductive. This is the second main surface of the light body. The solar cell element 6 (see FIG. 12) is installed on the second main surface 36 b of the light guide 36. The first main surface 36a of the light guide 36 is a light incident surface on which light L enters from the outside, and the portion of the second main surface 36b of the light guide 36 where the solar cell element 6 is installed is the sun. It is a light emission surface for emitting light L1 to the battery element 6.

The mixing ratio of the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c is, for example, as follows. The mixing ratio of the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c is shown as a volume ratio with respect to the substrate.

First phosphor 8a: BASF Lumogen F Violet 570 (trade name) 0.02%
Second phosphor 8b: BASF Lumogen F Yellow 083 (trade name) 0.02%
Third phosphor 8c: BASF Lumogen F Red 305 (trade name) 0.02%

FIGS. 17 to 20 are diagrams showing the emission characteristics and absorption characteristics of the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c. In FIG. 17, “first phosphor” indicates the spectrum of sunlight after ultraviolet light is absorbed by the first phosphor 8a, and “second phosphor” indicates that blue light is emitted by the second phosphor 8b. The spectrum of sunlight after being absorbed is shown, and “third phosphor” shows the spectrum of sunlight after green light is absorbed by the third phosphor 8c. In FIG. 18, “first phosphor + second phosphor + third phosphor” absorbs ultraviolet light, blue light, and green light by the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c. The spectrum of sunlight after being applied. In FIG. 19, “first phosphor” is an emission spectrum of the first phosphor 8 a, “second phosphor” is an emission spectrum of the second phosphor 8 b, and “third phosphor” is It is an emission spectrum of the 3rd fluorescent substance 8c. In FIG. 20, “first phosphor + second phosphor + third phosphor” is emitted from the first end face of the light guide including the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c. Is the spectrum of the emitted light.

As shown in FIGS. 17 and 18, the first phosphor 8a absorbs light having a wavelength of approximately 420 nm or less, and the second phosphor 8b absorbs light having a wavelength of approximately 420 nm or more and 520 nm or less. The phosphor 8c absorbs light having a wavelength of approximately 520 nm or more and 620 nm or less. The first phosphor 8a, the second phosphor 8b, and the third phosphor 8c absorb almost all light having a wavelength of 620 nm or less in the sunlight incident on the light guide. In the sunlight spectrum, the proportion of light having a wavelength of 620 nm or less is about 37%. Therefore, 37% of the light incident on the light incident surface of the light guide is absorbed by the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c included in the light guide.

As shown in FIG. 19, the emission spectrum of the first phosphor 8a has a peak wavelength at 430 nm, the emission spectrum of the second phosphor 8b has a peak wavelength at 520 nm, and the emission of the third phosphor 8c. The spectrum has a peak wavelength at 630 nm. However, as shown in FIG. 20, the spectrum of light emitted from the first end face of the light guide including the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c is the same as that of the third phosphor 8c. It has a peak wavelength only at a wavelength corresponding to the peak wavelength (630 nm) of the emission spectrum, and the peak wavelength (430 nm) of the emission spectrum of the first phosphor 8a and the peak wavelength (520 nm) of the emission spectrum of the second phosphor 8b. The corresponding wavelength does not have a peak wavelength.

The cause of the disappearance of the peak of the emission spectrum corresponding to the first phosphor 8a and the peak of the emission spectrum corresponding to the second phosphor 8b is the energy transfer between the phosphors due to photoluminescence (PL) and the Forster mechanism. Examples thereof include energy transfer between phosphors by (fluorescence resonance energy transfer). Energy transfer by photoluminescence occurs when fluorescence emitted from one phosphor is used as excitation energy for another phosphor. In the Förster mechanism, excitation energy directly moves between two adjacent phosphors by electron resonance without going through such light emission and absorption processes. Since energy transfer between phosphors by the Förster mechanism is performed without going through light emission and absorption processes, energy loss is small under optimum conditions. Therefore, it contributes to the improvement of the power generation efficiency of the solar cell module. In the present embodiment, in order to efficiently generate power while suppressing energy loss, the density of the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c is increased, and the Forster mechanism is used between the phosphors. Energy transfer is performed.

Here, the Förster mechanism will be described with reference to FIGS. 21 and 22. FIG. 21A is a diagram showing energy transfer by photoluminescence, and FIG. 21B is a diagram showing energy transfer by the Forster mechanism. FIG. 22A is a diagram for explaining a generation mechanism of energy transfer by the Förster mechanism, and FIG. 22B is a diagram showing energy transfer by the Förster mechanism.

As shown in FIG. 21B, in the phosphor of organic molecules or inorganic nanoparticles, energy transfer may occur from the excited molecule A to the ground molecule B by the Forster mechanism. In the phosphor, when the molecule A is excited and undergoes energy transfer to the molecule B, the molecule B emits light. This energy transfer depends on the distance between molecules, the emission spectrum of molecule A, and the absorption spectrum of molecule B. When the molecule A is a host molecule and the molecule B is a guest molecule, the rate constant k _{H → G} (movement probability) when energy is transferred is as shown in Equation (1).

In equation (1), ν is the frequency, f ′ _H (ν) is the emission spectrum of the host molecule A, ε (ν) is the absorption spectrum of the guest molecule B, N is the Avogadro constant, n is the refractive index, τ ₀ is the fluorescence lifetime of the host molecule A, R is the intermolecular distance, and K ² is the transition dipole moment (2/3 at random).

When the rate constant is large, energy transfer tends to occur between the phosphors. In order to obtain a large rate constant, it is desirable that the following conditions are satisfied.
[1] The overlap between the emission spectrum of the host molecule A and the absorption spectrum of the guest molecule is large. [2] The extinction coefficient of guest molecule B is large.
[3] The distance between the host molecule A and the guest molecule B is small.

[1] represents the ease of resonance between two adjacent phosphors. For example, as shown in FIG. 22A, when the peak wavelength of the emission spectrum of the host molecule A is close to the peak wavelength of the absorption spectrum of the guest molecule B, energy transfer due to the Forster mechanism is likely to occur. As shown in FIG. 22B, when the guest molecule B in the ground state exists near the host molecule A in the excited state, the wave function of the guest molecule A changes due to resonance properties, and the ground state host molecule A and An excited guest molecule B is formed. Thereby, energy transfer occurs between the host molecule A and the guest molecule B, and the guest molecule B emits light.

In the above [3], the intermolecular distance at which energy transfer by the Forster mechanism occurs is usually about 10 nm. If the conditions are met, energy transfer occurs even when the intermolecular distance is about 20 nm. If the mixing ratio of the first phosphor, the second phosphor, and the third phosphor described above is used, the distance between the phosphors is shorter than 20 nm. Therefore, energy transfer by the Forster mechanism can occur sufficiently. Moreover, the emission spectra and absorption spectra of the first phosphor, the second phosphor, and the third phosphor shown in FIGS. 17 and 19 sufficiently satisfy the condition [1]. Therefore, energy transfer from the first phosphor to the second phosphor and energy transfer from the second phosphor to the third phosphor occur, and the first phosphor, the second phosphor, and the third phosphor in this order. Cascade type energy transfer occurs.

In the light guide, although the phosphors having the three different emission spectra (the first phosphor, the second phosphor, and the third phosphor) are mixed, the light guide is substantially affected by the energy transfer by the Förster mechanism. In this case, only the emission of the third phosphor occurs. The emission quantum efficiency of the third phosphor is, for example, 92%. Therefore, by mixing the first phosphor, the second phosphor, and the third phosphor in the light guide, light in the wavelength region up to 620 nm is absorbed, and red light emission with a peak wavelength of 630 nm is achieved with an efficiency of 92%. Can be generated.

This type of energy transfer phenomenon is unique to organic phosphors and is generally considered not to occur in inorganic phosphors, but in some inorganic nanoparticle phosphors such as quantum dots, Those that cause energy transfer between inorganic materials or between inorganic materials and organic materials by a star mechanism are known.

For example, energy transfer occurs between two types of quantum dots having different sizes of ZnO / MgZnO core / shell structure. Since a quantum dot having a dimensional ratio of 1: √2 has a resonating exciton level, for example, 2 having a radius of 3 nm (peak wavelength of emission spectrum: 350 nm) and a radius of 4.5 nm (peak wavelength of emission spectrum: 357 nm). Between types of quantum dots, energy transfer occurs from small to large quantum dots. Energy transfer also occurs between two different sized quantum dots of the CdSe / ZnS core-shell structure. In addition, Mn2 + doped ZnSe quantum dots having a diameter of 8 nm to 9 nm have emission peaks at 450 nm and 580 nm, and are dye molecules 1 ', 3'-dihydro-1', 3 ', 3'-trimethyl-6-nitrospiro [ 2H-1-benzopyran-2,2 '-(2H) -indole] is in good agreement with the light absorption spectrum of ring-opened Spiropyran molecule (SPO open; Merocynanine form) Energy transfer to the dye molecule occurs. In general, an inorganic phosphor is superior in light resistance as compared with an organic phosphor, and thus is advantageous when used for a long period of time.

Usually, when two kinds of phosphors are mixed, as shown in FIG. 21A, the phosphor A first emits light with a certain efficiency, enters the phosphor B, and the phosphor B absorbs and emits light. Through this process, light is emitted from the phosphor B. In such energy transfer by photoluminescence, energy loss occurs in the light emission process in the phosphor A and the light absorption process in the phosphor B, and the energy transfer efficiency is small.

On the other hand, in the energy transfer by the Förster mechanism shown in FIG. 21 (b), only the energy moves directly between the phosphors, so that the energy transfer efficiency can be almost 100%, and the energy transfer is highly efficient. Movement can occur.

In addition, energy transfer by the Forster mechanism occurs not only in a luminescent material such as a phosphor, but also in a non-luminescent material that is excited by external light but deactivates without generating light. The final power generation amount depends on the fluorescence quantum yield of the guest molecule and does not depend on the fluorescence quantum yield of the host molecule. Therefore, even if only the guest molecule is composed of a phosphor having a high fluorescence quantum yield and the host molecule is composed of a phosphor having a low fluorescence quantum yield or a non-light emitting material that does not emit fluorescence, the same amount of power generation can be obtained. Therefore, as compared with the case where a high fluorescence quantum yield is required for all phosphors, such as when energy transfer is performed by photoluminescence, the range of material selection for the host molecule is widened.

FIG. 23 is a diagram showing a spectral sensitivity curve of an amorphous silicon solar cell which is an example of the solar cell element 6 together with an emission spectrum of the first phosphor, an emission spectrum of the second phosphor, and an emission spectrum of the third phosphor.

The spectrum of the light L1 emitted from the first end face 17c of the light guide body 17 substantially coincides with the emission spectrum of the third phosphor 8c. Therefore, the solar cell element 6 should just have a high sensitivity in the peak wavelength (630 nm) of the emission spectrum of the 3rd fluorescent substance 8c. As shown in FIG. 23, the amorphous silicon solar cell has the highest spectral sensitivity with respect to light having a wavelength near 600 nm. Comparing the spectral sensitivities of the amorphous silicon solar cells at the peak wavelengths of the emission spectra of the first phosphor, the second phosphor and the third phosphor, the peak wavelength of the emission spectrum of the third phosphor having the largest peak wavelength of the emission spectrum The spectral sensitivity of the amorphous silicon solar cell at is higher than the spectral sensitivity of the amorphous silicon solar cell at the peak wavelength of the emission spectrum of any of the other phosphors (first phosphor and second phosphor) provided in the light guide. large. Therefore, if an amorphous silicon solar cell is used as the solar cell element 6, power generation can be performed with high efficiency.

As described above, in the solar cell module 34 of the present embodiment, a part of the external light L incident on the light incident surface 36a is converted into a plurality of optical functional materials (first phosphor 8a, second phosphor 8b, third fluorescence). The light L1 emitted from the optical functional material (third phosphor 8c) having the largest peak wavelength of the emission spectrum, which is absorbed by the body 8c), causes energy transfer by the Forster mechanism between the plurality of optical functional materials. The light is condensed on a light exit surface having a smaller area than the light incident surface 36a and is incident on the solar cell element. Therefore, as the solar cell element, a solar cell having very high spectral sensitivity in a limited narrow wavelength range can be used, and a solar cell module with high power generation efficiency is provided.

[Thirteenth embodiment]
FIG. 24 is a cross-sectional view of the solar cell module 37 of the thirteenth embodiment.

The present embodiment is different from the first embodiment in that the optical functional material 8 is provided in the opposing region 38T of the light guide 38, and the concentration of the optical functional material 8 in the opposing region 38T is the optical functional material in the peripheral region 38F. This is the point where the density is lower than 8.

The base material and the optical functional material 8 constituting the light guide 38 are the same as those described in the first embodiment. In the first embodiment, a transparent region that allows external light to pass through the solar cell element as it is is formed in at least a part of the facing region. However, in the present embodiment, there is no such transparent region. When the counter area 38T is viewed from the light incident surface 38a side, the optical functional material 8 is dispersed throughout the counter area 38T.

In the case of this embodiment, the optical functional material 8 is dispersed at a uniform concentration throughout the opposing region 38T, but the configuration of the opposing region 38T is not limited to this. For example, the concentration of the optical functional material 8 may be different between the central portion and the peripheral portion (boundary portion with the peripheral region 38F) of the facing region 38T.

In the solar cell module 37 of the present embodiment, a part of the external light incident on the facing region 38T is absorbed by the optical functional material 8 and converted into fluorescence. Therefore, light in which external light and fluorescence are mixed enters the solar cell element 6 from the light exit surface 38c. Even in this configuration, the same effect as in the first embodiment can be obtained.

[Fourteenth embodiment]
FIG. 25 is a cross-sectional view of the solar cell module 39 of the fourteenth embodiment.

This embodiment is different from the first embodiment in that a transparent region in which the optical functional material 8 is not included is provided in a part of the peripheral region 40F of the light guide 40.

In the case of the present embodiment, a transparent region that allows external light to pass through is formed in the vicinity of the facing region 40T. Therefore, light incident obliquely to the light incident surface 40a out of light incident near the facing region 40T is incident on the solar cell element 6 from the light emitting surface 40c without being absorbed by the optical functional material 8. To do. Therefore, the external light that can be used for power generation can be increased.

[Deformation]
Although the suitable example of the solar cell module of this invention was shown in 1st Embodiment thru | or 14th Embodiment, the technical scope of this invention is not limited to said embodiment. The configurations shown in the first to fourteenth embodiments can be combined as appropriate, and various modifications can be made without departing from the gist of the present invention.

[Solar power generator]
FIG. 26 is a schematic configuration diagram of the solar power generation device 1000.

The solar power generation apparatus 1000 includes a solar cell module 1001 that converts sunlight energy into electric power, an inverter (DC / AC converter) 1004 that converts DC power output from the solar cell module 1001 into AC power, A storage battery 1005 that stores DC power output from the battery module 1001.

The solar cell module 1001 includes a light guide body 1002 that condenses sunlight and a solar cell element 1003 that generates power by the sunlight collected by the light guide body 1002. As the solar cell module 1001, for example, the solar cell module of the above-described embodiment is used.

The solar power generation apparatus 1000 supplies power to the external electronic device 1006. The electronic device 1006 is supplied with power from the auxiliary power source 1007 as necessary.

Since the photovoltaic power generation apparatus 1000 includes the above-described solar cell module according to the present invention, the photovoltaic power generation apparatus 1000 has a high power generation efficiency.

The present invention can be used for a solar cell module and a solar power generation device.

DESCRIPTION OF SYMBOLS 1 ... Solar cell module, 4 ... Light guide, 4a ... Light incident surface, 4c ... Light emission surface, 4F ... Peripheral area | region, 4T ... Opposite area | region, 5 ... Light guide, 5a ... Light incident surface, 5c ... Light emission Surface, 5F ... Peripheral region, 5T ... Opposite region, 6 ... Solar cell element, 6a ... Light receiving surface, 7 ... Reflective layer, 8, 8a, 8b, 8c ... Optical functional material (phosphor), 9 ... Reflective layer, 10 , 11, 12 ... solar cell module, 13 ... light guide, 13a ... light incident surface, 13c ... light exit surface, 13F ... peripheral region, 13T ... opposing region, 14, 15, 16, 17 ... solar cell module, 18 A layer containing no optical functional material, 19 a layer containing an optical functional material, 20 a light guide, 20a a light incident surface, 20c a light emitting surface, 20F a peripheral region, 20T a facing region, 21 a solar cell. Module, 22 ... layer not containing optical functional material, 23 ... layer containing optical functional material 24 ... layer not containing optical functional material, 25 ... light guide, 25a ... light incident surface, 25c ... light emitting surface, 25F ... peripheral region, 25T ... opposing region, 26 ... solar cell module, 27 ... optical functional material Including layer, 28 ... layer not including optical functional material, 29 ... light guide, 29a ... light incident surface, 29c ... light emitting surface, 29F ... peripheral region, 29T ... opposing region, 30 ... solar cell module, 31 ... light Layer containing functional material, 32 ... Layer not containing optical functional material, 33 ... Light guide, 33a ... Light incident surface, 33c ... Light emitting surface, 33F ... Peripheral region, 33T ... Counter region, 34 ... Solar cell module, 35 ... layer containing optical functional material, 36 ... light guide, 36a ... light incident surface, 36F ... peripheral region, 37 ... solar cell module, 38 ... light guide, 38a ... light incident surface, 38c ... light exit surface, 38F ... peripheral area, 38T ... opposite area 39 ... solar cell module, 40 ... light guide, 40a ... light incident surface, 40c ... light exit plane, 40F ... peripheral region, 40T ... opposed region, L ... external light, L1 ... fluorescent

Claims

A light guide that absorbs light incident from the outside by the phosphor and propagates the fluorescence emitted from the phosphor inside, and a solar cell element disposed on a surface facing the light incident surface of the light guide; The light guide includes a facing region facing the light receiving surface of the solar cell element, and a peripheral region around the facing region, and at least the peripheral region of the light guide A solar cell module in which the phosphor is provided in a part of the solar cell module.
The solar cell module according to claim 1, wherein the phosphor is not provided in at least a part of the facing region of the light guide.
The said opposing area | region of the said light guide is equipped with the said fluorescent substance, The density | concentration of the said fluorescent substance of the said opposing area | region is thinner than the density | concentration of the said fluorescent substance of the said peripheral area | region. Solar cell module.
The solar cell module according to any one of claims 1 to 3, wherein a thickness of the peripheral region of the light guide body increases as the thickness approaches the solar cell element.
The solar cell module according to any one of claims 1 to 4, wherein a plurality of the solar cell elements are installed on a surface of the light guide that faces the light incident surface.
6. The reflective layer for reflecting the fluorescence is provided on a portion of the surface of the light guide opposite to the light incident surface other than the portion where the solar cell element is installed. 2. The solar cell module according to item 1.
The solar cell module according to any one of claims 1 to 6, wherein a reflection layer that reflects the fluorescence is provided on an end surface adjacent to the light incident surface of the light guide.
The solar cell module according to any one of claims 1 to 7, wherein the light guide is formed by laminating a layer including the phosphor and a layer not including the phosphor.
The solar cell module according to any one of claims 1 to 8, wherein the light guide includes a plurality of types of phosphors as the phosphor.
The spectral sensitivity of the solar cell element at the peak wavelength of the emission spectrum of the phosphor having the largest emission spectrum peak wavelength among the plurality of types of phosphors is that of the solar cell element at the peak wavelength of the emission spectrum of the other phosphors. The solar cell module according to claim 9, wherein the solar cell module is larger than the spectral sensitivity.
When viewed from the normal direction of the light incident surface of the light guide, the area of the peripheral region of the light guide that is provided with the phosphor is the area of the counter region of the light guide. The solar cell module of any one of Claims 1 thru | or 10 larger than the area of the area | region where the fluorescent substance is not provided.
A solar power generation device comprising the solar cell module according to any one of claims 1 to 11.