Solar cell device and power generation device

Abstract

A solar cell apparatus (101) is provided with a base material (1). The base material (1) has a first surface (1a) that extends in a first direction (91) and in a second direction perpendicular to the first direction (91), and has an optical transparency. The first surface (1a) has a first region (61) and a second region (62) that are aligned along the first direction (91). The solar cell apparatus (101) is further provided with a reflecting film (2) that is disposed to cover the base material (1) in the first region (61), and a solar cell layer (3) that is disposed to cover the base material (1) in the second region (62). The portion in which the base material (1) and the reflecting film (2) overlap each other is so flexible that the length of the portion in the first direction (91) can be wound around at least once. The portion in which the base material (1) and the solar cell layer (3) overlap each other is so flexible that the length of the portion in the first direction (91) can be wound around at least once.

Description

Technical Field

[0001] The present invention relates to a solar cell device and a power generation device.

Background Art

[0002] An example of a solar cell is described in Japanese Patent Laid-Open No. 10-61117 (Patent Document 1). Patent Document 1 describes incorporating a solar cell into a waterproofing material on the roof or rooftop of a building. The solar cell described in Patent Document 1 is planar.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Planar solar cells are not only installed on the roofs of buildings, but may also be installed on the ground by constructing a scaffold in a large outdoor space. When such planar solar cells are installed, although they are efficient in absorbing sunlight, they prevent sunlight from reaching the ground in a large area that is shaded by the solar cells.

[0005] Also, it is preferable to be able to install solar cells even in places where it is difficult to install planar solar cells.

[0006] Therefore, an object of the present invention is to provide a solar cell device and a power generation device that can be installed using existing objects without significantly reducing the sunlight reaching the ground and can generate electricity efficiently.

Means for Solving the Problems

[0007] To achieve the above object, a solar cell device according to the present invention has a first surface extending in a first direction and a second direction perpendicular to the first direction, is translucent to sunlight, and the first surface has a first region and a second region arranged side by side along the first direction. The solar cell device includes a base material, a reflective film disposed to cover the base material in the first region and reflecting sunlight, and a solar cell layer disposed to cover the base material in the second region. A portion where the base material and the reflective film overlap is flexible enough to be wound around one or more times with the length of this portion in the first direction. A portion where the base material and the solar cell layer overlap is flexible enough to be wound around one or more times with the length of this portion in the first direction.

Advantages of the Invention

[0008] According to the present invention, it is possible to install using existing objects with little reduction in sunlight reaching the ground and to generate electricity efficiently.

Brief Description of the Drawings

[0009]

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BEST MODE FOR CARRYING OUT THE INVENTION

[0010] (Embodiment 1) With reference to FIGS. 1 to 7, a solar cell device according to Embodiment 1 based on the present invention will be described. A plan view of the solar cell device 101 in the present embodiment is shown in FIG. 1. A cross-sectional view of the solar cell device 101 is shown in FIG. 2. As shown in FIG. 1, the solar cell device 101 is in a strip shape. FIGS. 1 and 2 show a state in which the solar cell device 101 is expanded. The solar cell device 101 includes a first part 71 and a second part 72.

[0011] The solar cell device in this embodiment includes a base material 1, a reflective film 2, and a solar cell layer 3. The base material 1 has a first surface 1a that extends in a first direction 91 and a second direction 92 perpendicular to the first direction 91. The base material 1 has a second surface 1b as the surface opposite to the first surface 1a. The base material 1 is translucent to sunlight. In the present disclosure, "the base material is translucent" means that the base material has a transmittance of 50% or more at wavelengths in the visible light region and 30% or more at wavelengths in the infrared light region. Note that it is more preferable if the base material has a transmittance of 85% or more in the visible light region and 50% or more in the infrared light region. The base material 1 is formed of a flexible material. The base material 1 is formed of a resin such as PMMA (acrylic) resin, PET (polyethylene terephthalate) resin, PC (polycarbonate) resin, PEN (polyether nitrile) resin, SPS (polystyrene) resin, or cellulose acetate resin. It is particularly preferable that the base material 1 is formed of either PET resin or PEN resin. The thickness of the base material 1 is, for example, 100 μm or more and 125 μm or less. The first surface 1a has a first region 61 and a second region 62 arranged along the first direction 91. The first region 61 is a portion belonging to the first portion 71 of the first surface 1a. The second region 62 is a portion belonging to the second portion 72 of the first surface 1a.

[0012] The reflective film 2 is disposed so as to cover the base material 1 in the first region 61. The reflective film 2 is a film having a function of reflecting sunlight. The reflective film 2 is, for example, a metal foil. The reflective film 2 is formed of, for example, aluminum. The thickness of the reflective film 2 is, for example, 300 Å or more and 500 Å or less. The solar cell layer 3 is disposed so as to cover the base material 1 in the second region 62. The overlapping portion of the base material 1 and the reflective film 2, that is, the first portion 71, is flexible enough to be wound around one or more turns with the length in the first direction 91 of the first portion 71. The overlapping portion of the base material 1 and the solar cell layer 3, that is, the second portion 72, is flexible enough to be wound around one or more turns with the length in the first direction 91 of the second portion 72. In the example shown here, the solar cell device 101 is illustrated as being composed of the first portion 71 and the second portion 72 and not including other portions, but this is merely an example. The solar cell device 101 may include a portion that does not belong to either the first portion 71 or the second portion 72. In the example shown here, the first portion 71 and the second portion 72 are illustrated as being in contact, but this is merely an example. Other portions may be interposed between the first portion 71 and the second portion 72. Note that in the present disclosure, the statement that the reflective film 2 is "disposed so as to cover the base material 1 in the first region 61" is not limited to the arrangement where the reflective film 2 covers the entire surface of the first region 61, and there may be a portion in the first region 61 that is not covered by the reflective film 2. The same applies to the expression that the solar cell layer 3 is "disposed so as to cover the base material 1 in the second region 62", which is not limited to the arrangement where the solar cell layer 3 covers the entire surface of the second region 62, and there may be a portion in the second region 62 that is not covered by the solar cell layer 3. These also apply to the descriptions regarding the third region 63 and the fourth region 64 described later.

[0013] The solar cell layer 3 includes a first electrode layer 31, a semiconductor layer 32, and a second electrode layer 33. The semiconductor layer 32 is sandwiched between the first electrode layer 31 and the second electrode layer 32. The first electrode layer 31 may be formed of any material such as an aluminum alloy or SUS. The first electrode layer 31 is a transparent electrode. The thickness of the first electrode layer 31 is, for example, 200 Å or more and 1000 Å or less. The second electrode layer 32 may be formed of any material such as silver or an aluminum alloy. The thickness of the second electrode layer 32 is, for example, 500 Å or more and 1000 Å or less.

[0014] The solar cell layer 3 may be an inorganic solar cell or an organic solar cell. When the solar cell layer 3 is an inorganic solar cell, the material of the semiconductor layer 32 may be any of silicon, CIS, CIGS, CZTS, InP, SiGe, etc. Here, "CIS" refers to a chalcopyrite-based material composed of Cu, In, Ga, Al, Se, S, etc. "CIGS" refers to Cu(In,Ga)Se2. "CZTS" refers to Cu2ZnSnS4.

[0015] When the solar cell layer 3 is an organic solar cell, the solar cell layer 3 may be a dye-sensitized solar cell. In particular, the solar cell layer 3 may be a solar cell using a ruthenium complex dye. When the solar cell layer 3 is an organic solar cell, the material of the semiconductor layer 32 may be any of an organic thin film, perovskite, etc. Here, the organic thin film may be, for example, a combination of a conductive polymer and fullerene. Here, the perovskite may use CH3NH3PbI3, Spiro-OMeTAD, etc.

[0016] A partial enlarged plan view of the upper surface of the solar cell layer 3 in FIG. 2 is shown in FIG. 3. A partial enlarged plan view of the lower surface of the solar cell layer 3 in FIG. 2 is shown in FIG. 4. The second electrode layer 32 partially covers the upper surface of the semiconductor layer 32. In FIG. 2, five second electrode layers 32 are shown, but this is a schematic representation, and in reality, the number of second electrode layers 32 is not limited to five and may be more or less. The second electrode layer 32 is not necessarily just a striped pattern and may be formed in a shape that spreads two-dimensionally. The second electrode layer 32 may be, for example, a combination of a bus bar electrode extending in a strip shape and grid lines branching vertically from the bus bar electrode. The lower surface of the solar cell layer 3 is entirely covered by the first electrode layer 31.

[0017] The usage state of the solar cell device 101 is shown in FIG. 5. The solar cell device 101 is fixed in a state of being wound around the columnar object 10. In FIG. 5, the wiring drawn out from the solar cell device 101 is not shown. Wiring may be drawn out from the solar cell device 101. The wiring may be connected to some kind of power storage device or to some kind of device that uses electricity. Also, the wiring may be connected to a transmission line. The columnar object 10 is a tree. The columnar object 10 is, for example, a coniferous tree. The columnar object 10 is, for example, a tree such as cedar or cypress. The columnar object 10 stands on the ground 11. As shown in FIG. 5, the combination of the columnar object 10 and the solar cell device 101 can be regarded as a power generation device 501. A cross-sectional view when the power generation device 501 is cut in a horizontal plane is shown in FIG. 6. The power generation device 501 includes the columnar object 10 and the solar cell device 101, and the solar cell device 101 is wound around the columnar object 10. The ground 11 is not part of the power generation device 501. The solar cell device 101 is wound around the columnar object 10 more than two times.

[0018] A more detailed cross-sectional view is shown in FIG. 7. A magnified part of FIG. 7 is shown in FIG. 8. The first part 71 is first wound around the outer peripheral surface of the columnar object 10, and the second part 72 is wound around the outside of that. Therefore, the first part 71 is in a state of being covered by the second part 72.

[0019] According to the solar cell device 101 in this embodiment, by winding and fixing it around an existing columnar object, it can be installed so as to receive sunlight, and the sunlight incident on the columnar object can be effectively utilized to generate electrical energy. In this embodiment, it can be installed using existing objects without reducing the sunlight reaching the ground as much as possible, and can generate electricity efficiently.

[0020] As shown in FIG. 8, a light component 12a, which is a part of the sunlight rays reaching the solar cell device 101, is converted into electrical energy in the semiconductor layer 32 of the solar cell layer 3. A light component 12b, which is a part of the sunlight rays reaching the solar cell layer 3 and passing through it, is reflected by the reflective film 2 disposed on the surface of the first portion 71. Since the light component 12b reflected by the reflective film 2 is incident on the semiconductor layer 32 again, it is converted into electrical energy at a certain rate. In this embodiment, for the light component 12b that could not be converted into electrical energy and was transmitted during the first incidence on the solar cell layer 3, it can be made to be incident on the solar cell layer 3 again by being reflected by the reflective film 2. Therefore, a decrease in the photoelectric conversion efficiency can be suppressed, and electricity can be generated efficiently.

[0021] In this embodiment, as shown in FIGS. 7 and 8, since the base material 1 always exists between the reflective film 2 and the columnar object 10, when the reflective film 2 is formed of metal and the columnar object 10 is a tree, it is difficult for the reflective film 2 to directly come into contact with moisture or the like coming out of the tree, and the probability of the reflective film 2 being corroded can be reduced. It is preferable to roughen the second surface 1b of the base material 1, because the adhesion between the base material 1 and the columnar object 10 can be enhanced. An adhesive may be disposed between the base material 1 and the columnar object 10.

[0022] In addition, in FIG. 5, an example using a tree as the columnar object 10 is shown, but the columnar object is not limited to a tree. For example, as shown in FIG. 9, the solar cell device 101 may be wound around the columnar object 10i. The columnar object 10i is a power pole or a telegraph pole. The columnar object may be, among others, for example, a streetlight pole, a road sign pole, an antenna pole, a signboard pole, a building column, a bridge pier, etc.

[0023] Regarding the solar cell device shown in the following embodiments, by the same concept, it can be combined with some kind of columnar object to form a power generation device.

[0024] Note that in FIGS. 1, 2, and 5, the cable coming out of the solar cell device 101 is not shown, but actually, a cable may be appropriately drawn out from the solar cell device 101. The tip of the cable drawn out from the solar cell device 101 may be connected to some other device. The "some other device" mentioned here may be, for example, a power storage device. Some device that consumes power may be connected to the solar cell device 101 and it may be set to consume the generated electricity by that device. As some device that consumes power, some measurement device, recording device, lighting device, etc. can be considered. This applies not only to the solar cell device 101 in this embodiment but also to each of the following embodiments.

[0025] (Embodiment 2) With reference to FIGS. 10 to 11, the solar cell device according to Embodiment 2 based on the present invention will be described. The plan view of the solar cell device 102 in this embodiment is shown in FIG. 10. The basic configuration of the solar cell device 102 is common to the configuration of the solar cell device 101 described in Embodiment 1. The solar cell device 102 further has the following configuration.

[0026] Assuming that the dimension along the first direction 91 of the first region 61 is X1, the dimension along the second direction 92 of the first region 61 is Y1, the dimension along the first direction 91 of the second region 62 is X2, and the dimension along the second direction 92 of the second region 62 is Y2, then X1≥X2 and Y1≥Y2. In FIG. 10, since the first surface 1a of the base material 1 is covered by other films, it cannot be seen directly. Therefore, although the first region 61 and the second region 62 defined as partial regions of the first surface 1a are not shown in FIG. 10, the first region 61 exists in the first part 71 and the second region 62 exists in the second part 72.

[0027] The usage state of the solar cell device 102 is shown in FIG. 11. The solar cell device 102 is fixed in a state of being wound around the columnar object 10. The combination of the columnar object 10 and the solar cell device 101 can be regarded as a power generation device 502.

[0028] In the present embodiment, since Y1≧Y2, the first portion 71 where the reflective film 2 exists has a larger dimension in the vertical direction, and the first portion 71 protrudes more than the second portion 72 wound from the outside thereof. That is, as shown in FIG. 11, in the wound state, the first portion 71 protrudes above and below the second portion 72. Therefore, even if some winding deviation occurs, the second portion 72 will surely fit on the outer peripheral surface where the first portion 71 has already been wound. As a result, the reflective film 2 can be made to overlap the solar cell layer 3 more reliably. Therefore, the reflective film 2 can function more reliably. In addition, the solar cell layer 3 existing in the second portion 72 can be protected from moisture generated from the columnar object 10 and the like.

[0029] Incidentally, as a modification, a solar cell device 103 as shown in FIG. 12 is also conceivable. As the solar cell device 103, holes 6 are provided along the upper side and the lower side of the first portion 71. The holes 6 are for passing a rope. FIG. 13 shows the state where the solar cell device 103 is wound around and fixed to the columnar object 10. In the wound state, the upper and lower portions of the first portion 71 located inside protrude from the second portion 72 located outside. Therefore, by passing the rope 7 through the holes 6 in this portion, the solar cell device 103 can be stably fixed to the columnar object 10. The number of the holes 6 shown in FIG. 12 is merely an example and is not necessarily the case. The way of passing the rope 7 shown in FIG. 13 is merely an example and is not necessarily the case.

[0030] (Embodiment 3) With reference to FIGS. 14 to 15, a solar cell device according to Embodiment 3 based on the present invention will be described. A cross-sectional view of the solar cell device 104 in the present embodiment is shown in FIG. 14. The basic configuration of the solar cell device 104 is common to the configuration of the solar cell device 101 described in Embodiment 1.

[0031] In the solar cell device 104, the first surface 1a has a third region 63 of the second region 62, which is located on the side opposite to the first region 61, along the first direction 91. In the third region 63, the down-conversion film 4 is disposed so as to cover the base material 1. The down-conversion film 4 is a film that converts the wavelength of light in the light wavelength region outside the visible light region, such as ultraviolet light, which has no sensitivity in a normal semiconductor, into the wavelength of the visible light region. The solar cell device 104 includes a first portion 71, a second portion 72, and a third portion 73. The third region 63 exists in the third portion. A partial cross-sectional view when the solar cell device 104 is wound around the columnar object 10 is shown in FIG. 15.

[0032] As shown in FIG. 15, the light component 12a1 in the visible light region passes through the third portion 73 and is incident on the semiconductor layer 32 in the second portion 72 and is converted into electrical energy. The light component 12a2 such as ultraviolet light is converted into the light component 12a3 in the visible light region in the down-conversion film 4 and then is incident on the semiconductor layer 32, where it is converted into electrical energy. The light component 12c that has passed through the solar cell layer 3 without being converted into electrical energy in the semiconductor layer 32 is reflected by the reflection film 2 in the first portion 71 and is incident on the semiconductor layer 32 of the solar cell layer 3 again. The light component 12c includes the component of the light component 12a1 in the visible light region that has passed through the solar cell layer 3 without being converted into electrical energy in the semiconductor layer 32 and the component of the light component 12a3 generated in the down-conversion film 4 that has passed through the solar cell layer 3 without being converted into electrical energy in the semiconductor layer 32.

[0033] In the present embodiment, for the light component 12c that could not be converted into electrical energy and was transmitted during the first incidence on the solar cell layer 3, it can be made to be incident on the solar cell layer 3 again by being reflected by the reflection film 2, so that the photoelectric conversion efficiency can be improved.

[0034] (Embodiment 4) Referring to FIGS. 16 to 17, a solar cell device according to Embodiment 4 of the present invention will be described. A cross-sectional view of the solar cell device 105 in this embodiment is shown in FIG. 16. The basic configuration of the solar cell device 105 is common to the configuration of the solar cell device 104 described in Embodiment 3.

[0035] In the solar cell device 105, the first surface 1a has a fourth region 64 of the third region 63, which is located on the side opposite to the second region 62, along the first direction 91. In the fourth region 64, an infrared-responsive photoelectric conversion element 5 is disposed so as to cover the base material 1. The photoelectric conversion element 5 includes an electrode layer 51, a photoelectric conversion layer 52, and an electrode layer 53. The photoelectric conversion layer 52 is sandwiched between the electrode layer 51 and the electrode layer 53. Since the photoelectric conversion element 5 is infrared-responsive, infrared light can be converted into electrical energy. The solar cell device 105 includes a first portion 71, a second portion 72, a third portion 73, and a fourth portion 74. The fourth region 64 exists in the fourth portion. A partial cross-sectional view of the solar cell device 105 when wound around the columnar object 10 is shown in FIG. 17.

[0036] As shown in FIG. 17, the light component 12a1 in the visible light region passes through the fourth portion 74 and the third portion 73 and is incident on the semiconductor layer 32 in the second portion 72, where it is converted into electrical energy. The light component 12a2 such as ultraviolet light is converted into the light component 12a3 in the visible light region in the down-conversion film 4 and then is incident on the semiconductor layer 32, where it is converted into electrical energy. The light component 12c that passes through the solar cell layer 3 without being converted into electrical energy in the semiconductor layer 32 is reflected by the reflection film 2 in the first portion 71 and is incident on the semiconductor layer 32 of the solar cell layer 3 again. The light component 12a4 in the infrared region is incident on the photoelectric conversion layer 52 in the fourth portion 74 and is converted into electrical energy. The light component 12a2 such as ultraviolet light passes through the fourth portion 74, is converted into the light component 12a3 in the visible light region in the down-conversion film 4 in the third portion 73, and then is incident on the semiconductor layer 32, where it is converted into electrical energy. The light component 12c that passes through the solar cell layer 3 without being converted into electrical energy in the semiconductor layer 32 is reflected by the reflection film 2 in the first portion 71 and is incident on the semiconductor layer 32 of the solar cell layer 3 again. A part of the light component 12c reflected by the reflection film 2 may pass through the third portion 73 and be incident on the photoelectric conversion layer 52 in the fourth portion 74. The infrared region component of the light component 12c can be converted into electrical energy in the photoelectric conversion layer 52 after being reflected by the reflection film 2. In this way, the photoelectric conversion efficiency can be improved.

[0037] Incidentally, what can be said in common to the embodiments described so far is that the solar cell layer 3 includes, in order from the side closer to the base material 1, a first electrode layer 31, a semiconductor layer 32, and a second electrode layer 33, and it is preferable that the thickness of the reflection film 2 is larger than the thickness of the first electrode layer 31. If the reflection film 2 has such a thick configuration, the component of the light incident on the reflection film 2 that passes through the reflection film 2 can be suppressed to a small amount, and most components can be reflected.

[0038] Incidentally, a plurality of the above-described embodiments may be appropriately combined and adopted. It should be noted that the above-described embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is shown by the claims and includes all modifications within the meaning and scope equivalent to the claims.

Explanation of Reference Numerals

[0039] 1 Substrate, 1a First surface, 1b Second surface, 2 Reflective film, 3 Solar cell layer, 4 Down-conversion film, 5 Photoelectric conversion element, 6 Hole, 7 Rope, 10, 10i Columnar object, 11 Ground, 12a, 12a1, 12a2, 12a3, 12a4, 12b, 12c Light component, 31 First electrode layer, 32 Semiconductor layer, 33 Second electrode layer, 51, 53 Electrode layer, 52 Photoelectric conversion layer, 61 First region, 62 Second region, 63 Third region, 64 Fourth region, 71 First part, 72 Second part, 91 First direction, 92 Second direction, 101, 102, 103, 104, 105 Solar cell device, 501, 501i Power generation device.

Claims

1. A substrate having a first surface extending in a first direction and a second direction perpendicular to the first direction, the substrate being translucent to sunlight, the first surface having a first region and a second region arranged along the first direction, A reflective film disposed to cover the substrate in the first region and reflecting sunlight, A solar cell layer disposed to cover the substrate in the second region, A portion where the substrate and the reflective film overlap and the solar cell layer does not overlap is flexible enough to be wound around one or more times with the length of the portion in the first direction, A solar cell device, wherein a portion where the substrate and the solar cell layer overlap is flexible enough to be wound around one or more times with the length of the portion in the first direction.

2. A substrate having a first surface extending in a first direction and a second direction perpendicular to the first direction, the substrate being translucent to sunlight, the first surface having a first region and a second region arranged along the first direction, A reflective film disposed to cover the substrate in the first region and reflecting sunlight, A solar cell layer disposed to cover the substrate in the second region, A portion where the substrate and the reflective film overlap is flexible enough to be wound around one or more times with the length of the portion in the first direction, A portion where the substrate and the solar cell layer overlap is flexible enough to be wound around one or more times with the length of the portion in the first direction, If the dimension of the first region along the first direction is X1, the dimension of the first region along the second direction is Y1, the dimension of the second region along the first direction is X2, and the dimension of the second region along the second direction is Y2, then X1≥X2 and Y1≥Y2. A solar cell device.

3. The first surface has a third region along the first direction, the third region being located on the side opposite to the first region of the second region, In the third region, a down-conversion film is disposed to cover the substrate. The solar cell device according to claim 1 or 2.

4. The first surface has a fourth region along the first direction, the fourth region being located on the side opposite to the second region of the third region, In the fourth region, an infrared-responsive photoelectric conversion element is disposed to cover the substrate. The solar cell device according to claim 3.

5. The solar cell layer includes, in order from the side closer to the base material, a first electrode layer, a semiconductor layer, and a second electrode layer, and the thickness of the reflection film is greater than the thickness of the first electrode layer. The solar cell device according to claim 1 or 2.

6. A columnar object, and a solar cell device according to claim 1 or 2, wherein the solar cell device is wound around the columnar object, and is a power generation device.

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