Solar cell device

Abstract

To provide a solar cell device that can suppress the loss when light is guided.SOLUTION: A solar cell device includes: a first solar cell including a first transparent substrate having a first main surface and a second main surface facing the first main surface, a first power generation element attached to the first transparent substrate, and a first liquid crystal layer disposed on the second main surface side and having a cholesteric liquid crystal containing a plurality of liquid crystal molecules; a second solar cell including a second transparent substrate having a third main surface and a fourth main surface facing the third main surface, a second power generation element attached to the second transparent substrate, and a second liquid crystal layer disposed on the fourth main surface side and having a cholesteric liquid crystal containing a plurality of liquid crystal molecules; and an adhesive layer that attaches the first solar cell and the second solar cell together.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] Embodiments of the present invention relate to a solar cell device.

Background Art

[0002] For example, a liquid crystal polarization grating using a liquid crystal material has been proposed. In such a liquid crystal polarization grating, from the viewpoint of obtaining desired reflection performance, adjustment of various parameters such as the grating period T, the refractive index anisotropy Δn of the liquid crystal layer (the difference between the refractive index ne for extraordinary light and the refractive index no for ordinary light of the liquid crystal layer), and the thickness d of the liquid crystal layer is required.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] An object of the present embodiment is to provide a solar cell device capable of suppressing loss when guiding light.

Means for Solving the Problem

[0005] According to the present embodiment, there is provided a solar cell device including: a first solar cell having a first transparent substrate having a first main surface and a second main surface opposite to the first main surface, a first power generation element bonded to the first transparent substrate, and a first liquid crystal layer disposed on the second main surface side and having a cholesteric liquid crystal containing a plurality of liquid crystal molecules; a second solar cell having a second transparent substrate having a third main surface and a fourth main surface opposite to the third main surface, a second power generation element bonded to the second transparent substrate, and a second liquid crystal layer disposed on the fourth main surface side and having a cholesteric liquid crystal containing a plurality of liquid crystal molecules; and an adhesive layer that bonds the first solar cell and the second solar cell to each other.

Brief Description of the Drawings

[0006] [Figure 1] Figure 1 is a schematic cross-sectional view showing a solar cell according to the first embodiment. [Figure 2] Figure 2 is a diagram illustrating an example of a cholesteric liquid crystal contained in a liquid crystal layer. [Figure 3] Figure 3 is a schematic plan view showing a solar cell according to the first embodiment. [Figure 4] Figure 4 is a schematic diagram showing a solar cell device according to the first embodiment. [Figure 5] Figure 5 is a plan view showing a modified example of the first embodiment. [Figure 6] Figure 6 is a schematic cross-sectional view showing a solar cell according to the second embodiment. [Figure 7] Figure 7 is a schematic diagram showing a solar cell device according to the second embodiment. [Figure 8] Figure 8 is a plan view showing a modified example of the second embodiment. [Figure 9] Figure 9 is a schematic diagram showing a solar cell device according to the third embodiment. [Figure 10] Figure 10 is a schematic diagram showing a solar cell device according to the fourth embodiment. [Figure 11] Figure 11 is a schematic diagram showing a solar cell device according to the fifth embodiment. [Figure 12] Figure 12 is a schematic diagram showing a solar cell device according to the sixth embodiment. [Figure 13] Figure 13 is a schematic diagram showing a solar cell device according to the seventh embodiment. [Figure 14] Figure 14 is a schematic diagram showing a solar cell device according to the eighth embodiment. [Figure 15] Figure 15 is a schematic diagram showing a solar cell device according to the ninth embodiment. [Modes for carrying out the invention]

[0007] Hereinafter, this embodiment will be described with reference to the drawings. It should be noted that the disclosure is merely an example, and any modifications that a person skilled in the art could easily conceive while maintaining the spirit of the invention are naturally included within the scope of the present invention. Furthermore, the drawings may schematically represent the width, thickness, shape, etc., of each part compared to the actual embodiment in order to clarify the explanation; however, these are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and in each drawing, components that perform the same or similar functions as those described above in previously shown drawings are denoted by the same reference numerals, and redundant detailed explanations may be omitted as appropriate.

[0008] [First Embodiment] Figure 1 is a schematic cross-sectional view showing a solar cell C11 of the first embodiment. Furthermore, the drawings will include mutually orthogonal X, Y, and Z axes as needed to facilitate understanding. The direction along the X axis is referred to as the X direction or first direction, the direction along the Y axis as the Y direction or second direction, and the direction along the Z axis as the Z direction or third direction. The plane defined by the X and Y axes is referred to as the XY plane, the plane defined by the Y and Z axes as the YZ plane, and the plane defined by the X and Z axes as the XZ plane. Viewing the XY plane is called a plan view.

[0009] The solar cell (first solar cell) C11 comprises a transparent substrate (first transparent substrate) T11, a power generation element (first power generation element) E11, and a liquid crystal layer (first liquid crystal layer) 311.

[0010] The transparent substrate T11 is made of, for example, a transparent glass plate or a transparent synthetic resin plate. The transparent substrate T11 may also be made of, for example, a flexible transparent synthetic resin plate.

[0011] The transparent substrate T11 is formed in a flat plate shape along the X-Y plane, and has a first main surface F1, a second main surface F2, and a side surface (first side surface) SS1. The first main surface F1 and the second main surface F2 are surfaces substantially parallel to the X-Y plane, and face each other in the third direction Z. Note that the transparent substrate T11 may take any shape. For example, the transparent substrate T11 may be curved.

[0012] In this specification, "light" includes visible light and invisible light. For example, the lower limit wavelength of the visible light region is 360 nm or more and 400 nm or less, and the upper limit wavelength of the visible light region is 760 nm or more and 830 nm or less. Visible light includes a first component (blue component) in a first wavelength band (e.g., 400 nm to 500 nm), a second component (green component) in a second wavelength band (e.g., 500 nm to 600 nm), and a third component (red component) in a third wavelength band (e.g., 600 nm to 700 nm). Invisible light includes ultraviolet rays in a wavelength band shorter than the first wavelength band, and infrared rays in a wavelength band longer than the third wavelength band. In this specification, "transparent" is preferably colorless and transparent. However, "transparent" may be translucent or colored and transparent.

[0013] The power generation element E11 is bonded to the transparent substrate T11. In the first embodiment, the power generation element E11 is bonded to the side surface SS1. The power generation element E11 has a light receiving surface RS. The light receiving surface RS faces the side surface SS1. Although not illustrated, the adhesive that bonds the transparent substrate T11 and the light receiving surface RS is transparent, and preferably has a refractive index equivalent to that of the transparent substrate T11. For example, a UV-curable acrylic adhesive or the like is used.

[0014] Examples of the power generation element E11 include silicon-based solar cells, organic thin-film solar cells, and the like. The silicon-based solar cell is formed using amorphous silicon, microcrystalline silicon, single-crystal silicon, polycrystalline silicon, or the like. The organic thin-film solar cell includes organic semiconductor solar cells, perovskite solar cells, and the like, and may have light transmittance depending on the materials used. The power generation element E11 of the present embodiment is, for example, a single-crystal silicon solar cell. Further, the power generation element E11 generates power by receiving, for example, non-visible light, particularly infrared rays.

[0015] The liquid crystal layer 311 is disposed on the side of the second main surface F2 of the transparent substrate T11. Although not shown in FIG. 1, the solar cell C11 may include an alignment film interposed between the transparent substrate T11 and the liquid crystal layer 311.

[0016] The liquid crystal layer 311 has a cholesteric liquid crystal 31 as schematically shown in an enlarged manner. The cholesteric liquid crystal 31 has a helical axis AX substantially parallel to the third direction Z, and has a helical pitch P along the third direction Z. The helical pitch P represents one period of the helix (the layer thickness along the helical axis AX required for liquid crystal molecules to rotate 360 degrees).

[0017] Such a liquid crystal layer 311 reflects, of the light LTi incident through the transparent substrate T11, circularly polarized light in a selective reflection band determined according to the helical pitch P and the refractive index anisotropy Δn. In this specification, "reflection" in the liquid crystal layer 311 involves diffraction inside the liquid crystal layer 311.

[0018] In the liquid crystal layer 311, the cholesteric liquid crystal 31 has a reflection surface 32 that reflects circularly polarized light corresponding to the turning direction of the cholesteric liquid crystal 31 within the selective reflection band. In this specification, the circularly polarized light may be strictly circularly polarized light, or may be circularly polarized light approximated to elliptically polarized light.

[0019] Next, the optical action of the solar cell C11 will be described.

[0020] The illustrated example describes the case where the liquid crystal layer 311 reflects at least a portion of the light LTi incident from the side of the transparent substrate T11 back towards the transparent substrate T11.

[0021] The light LTi incident on solar cell C11 includes, for example, visible light, ultraviolet light, and infrared light. For the sake of clarity, we will assume that the optical LTi is incident approximately perpendicularly to the transparent substrate T11. The incident angle of the optical LTi on the transparent substrate T11 is not particularly limited.

[0022] Light LTi enters the interior of the transparent substrate T11 from the first main surface F1, exits from the second main surface F2, and enters the liquid crystal layer 311. The liquid crystal layer 311 then reflects a portion of the light LTi towards the transparent substrate T11 at the reflective surface 32, while transmitting the remaining light. The reflected light LTr is circularly polarized light with wavelength λ. For example, wavelength λ is in the infrared wavelength band. The light LTr that has passed through the liquid crystal layer 311 includes, for example, visible light.

[0023] The angle θa at which the light LTr reflected by the liquid crystal layer 311 enters the transparent substrate T11 is set to satisfy the optical waveguide conditions in the transparent substrate T11. Here, the angle θa corresponds to an angle greater than or equal to the critical angle at which total internal reflection occurs at the interface between the transparent substrate T11 and the air. The angle θa represents the angle with respect to a perpendicular line perpendicular to the first main surface F1 of the transparent substrate T11.

[0024] If the transparent substrate T11 and the liquid crystal layer 311 have equivalent refractive indices, these laminates can function as a single optical waveguide. In this case, the optical LTr is guided by repeated reflections at the interface between the transparent substrate T11 and the air, and at the interface between the liquid crystal layer 311 and the air.

[0025] The light LTr guided by total internal reflection reaches the light-receiving surface RS of the power generation element E11, causing the power generation element E11 to generate electricity.

[0026] Figure 2 is a diagram illustrating an example of a cholesteric liquid crystal 31 contained in the liquid crystal layer 311. In Figure 2, the liquid crystal layer 311 is shown enlarged in the third direction Z. For simplification, one liquid crystal molecule LM1 is shown as the liquid crystal molecule LM1 constituting the cholesteric liquid crystal 31, among multiple liquid crystal molecules located in the same plane parallel to the XY plane. The orientation direction of the shown liquid crystal molecule LM1 corresponds to the average orientation direction of multiple liquid crystal molecules located in the same plane.

[0027] Focusing on one cholesteric liquid crystal 31 enclosed by a dotted line, the cholesteric liquid crystal 31 is composed of multiple liquid crystal molecules LM1 that are spirally stacked along the third direction Z while rotating. The multiple liquid crystal molecules LM1 include liquid crystal molecules LM11 on one end of the cholesteric liquid crystal 31 and liquid crystal molecules LM12 on the other end of the cholesteric liquid crystal 31. The liquid crystal molecules LM11 are in close proximity to the transparent substrate T11.

[0028] In the liquid crystal layer 311, the orientation directions of adjacent cholesteric liquid crystals 31 along the second direction Y are different from each other. Furthermore, the spatial phases of adjacent cholesteric liquid crystals 31 along the second direction Y are different from each other. The orientation directions of adjacent liquid crystal molecules LM11 along the second direction Y are different from each other. The orientation directions of multiple liquid crystal molecules LM11 change continuously along the second direction Y. The orientation directions of adjacent liquid crystal molecules LM12 along the second direction Y are also different from each other. The orientation directions of multiple liquid crystal molecules LM12 also change continuously along the second direction Y.

[0029] The reflective surface 32 of the liquid crystal layer 311, shown by the dashed line in the figure, is inclined with respect to the XY plane. The angle between the reflective surface 32 and the XY plane is called the inclination angle θ of the reflective surface 32. The inclination angle θ is acute. The reflective surface 32 corresponds to a surface where the orientation directions of the liquid crystal molecules LM1 are aligned, or a surface where the spatial phases are aligned (equal phase surface).

[0030] In this type of liquid crystal layer 311, the orientation direction of the liquid crystal molecules LM1 is fixed during curing. In other words, the orientation direction of the liquid crystal molecules LM1 is not controlled in response to the electric field. For this reason, the solar cell C11 does not have electrodes to form an electric field in the liquid crystal layer 311.

[0031] Generally, in a liquid crystal layer having a cholesteric liquid crystal, the selective reflection band Δλ for light incident perpendicularly is given by the following equation (1), based on the helical pitch P of the cholesteric liquid crystal and the refractive index anisotropy Δn of the liquid crystal layer (the difference between the refractive index ne for extraordinary light and the refractive index no for ordinary light). Δλ = Δn * P …(1) The specific wavelength range for the selective reflection band Δλ is between (no*P) and (ne*P).

[0032] Figure 3 is a schematic plan view showing the solar cell C11 of the first embodiment. Figure 3 shows an example of the spatial phase of the cholesteric liquid crystal 31. The spatial phase shown here represents the orientation direction of the liquid crystal molecules LM11 located near the transparent substrate T11, among the liquid crystal molecules LM1 contained in the cholesteric liquid crystal 31.

[0033] For each of the cholesteric liquid crystals 31 aligned along the second direction Y, the orientation direction of the liquid crystal molecules LM11 is different from that of the others. In other words, the spatial phases of the cholesteric liquid crystals 31 differ along the second direction Y.

[0034] On the other hand, for each of the cholesteric liquid crystals 31 aligned along the first direction X, the orientation direction of the liquid crystal molecules LM11 is approximately the same. In other words, the spatial phases of the cholesteric liquid crystals 31 are approximately the same in the first direction X.

[0035] In particular, focusing on the cholesteric liquid crystals 31 aligned in the second direction Y, the orientation direction of each liquid crystal molecule LM11 differs by a certain angle. That is, the orientation direction of multiple liquid crystal molecules LM11 aligned along the second direction Y changes linearly. Therefore, the spatial phase of the cholesteric liquid crystals 31 aligned along the second direction Y changes linearly along the second direction Y. As a result, a reflective surface 32 tilted with respect to the XY plane is formed, as shown in the liquid crystal layer 311 in Figure 2. "Linear change" here means, for example, that the amount of change in the orientation direction of the liquid crystal molecules LM11 can be expressed by a linear function. Note that the orientation direction of the liquid crystal molecules LM11 here corresponds to the long axis direction of the liquid crystal molecules LM11 in the XY plane.

[0036] Here, within a single plane, the period T is defined as the distance between two liquid crystal molecules LM11 when their orientation direction changes by 180 degrees along the second direction Y. In Figure 3, DP indicates the rotational direction of the liquid crystal molecules LM11. The inclination angle θ of the reflective surface 32 shown in Figure 2 is appropriately set by the period T and the helical pitch P.

[0037] Figure 4 is a schematic diagram showing the solar cell apparatus 100 of the first embodiment. Figure 4(a) is a cross-sectional view showing the solar cell apparatus 100 along the YZ plane. Figure 4(b) is a plan view showing the solar cell apparatus 100 along the XY plane.

[0038] The solar cell device 100 includes a solar cell C11, a solar cell (second solar cell) C21, a solar cell C31, an adhesive layer AD1 that bonds solar cell C11 and solar cell C21 to each other, and an adhesive layer AD2 that bonds solar cell C21 and solar cell C31 to each other. Solar cells C11, C21, and C31 are arranged in this order in the second direction Y.

[0039] Solar cell C21 comprises a transparent substrate (second transparent substrate) T21, a power generation element (second power generation element) E21, and a liquid crystal layer (second liquid crystal layer) 321.

[0040] The transparent substrate T21 is formed from the same material as, for example, the transparent substrate T11. The transparent substrate T21 is formed in a flat plate shape along the XY plane and has a third main surface F3, a fourth main surface F4, a side surface (second side surface) SS2, and a side surface (third side surface) SS3. The third main surface F3 and the fourth main surface F4 are planes substantially parallel to the XY plane and face each other in the third direction Z. The side surfaces SS2 and SS3 face each other in the second direction Y.

[0041] The power generation element E21 is bonded to the transparent substrate T21. In the first embodiment, the power generation element E21 is bonded to the side surface SS3. The power generation element E21 has a light-receiving surface facing the side surface SS3. The power generation element E21 is the same solar cell as the power generation element E11.

[0042] The liquid crystal layer 321 is located on the side of the fourth main surface F4 of the transparent substrate T21. Like the liquid crystal layer 311, the liquid crystal layer 321 has a cholesteric liquid crystal containing multiple liquid crystal molecules.

[0043] The side SS2 and the power generation element E11 are bonded to each other by an adhesive layer AD1. The adhesive layer AD1 is made of a transparent or opaque resin. For example, the adhesive layer AD1 is made of a silicone resin.

[0044] The solar cell C31 comprises a transparent substrate T31, a power generation element E31, and a liquid crystal layer 331.

[0045] The transparent substrate T31 is formed from the same material as, for example, the transparent substrate T11. The transparent substrate T31 is formed in a flat plate shape along the XY plane and has a fifth main surface F5, a sixth main surface F6, a side surface SS4, and a side surface SS5. The fifth main surface F5 and the sixth main surface F6 are planes substantially parallel to the XY plane and face each other in the third direction Z. The side surfaces SS4 and SS5 face each other in the second direction Y.

[0046] The power generation element E31 is bonded to the transparent substrate T31. In the first embodiment, the power generation element E31 is bonded to the side surface SS5. The power generation element E31 has a light-receiving surface facing the side surface SS5. The power generation element E31 is the same solar cell as the power generation element E11.

[0047] The liquid crystal layer 331 is located on the side of the sixth main surface F6 of the transparent substrate T31. Like the liquid crystal layer 311, the liquid crystal layer 331 has a cholesteric liquid crystal containing multiple liquid crystal molecules.

[0048] The side SS4 and the power generation element E21 are bonded to each other by adhesive layer AD2. Adhesive layer AD2 is formed using the same material as adhesive layer AD1.

[0049] The transparent substrate T11 has a width WT1 in the first direction X. The width WT1 is, for example, about 10 cm. The transparent substrate T11 has a width WT2 in the second direction Y. The width WT2 is, for example, about 10 cm. The transparent substrate T11 has a thickness TT in the third direction Z. The thickness TT is, for example, about 10 mm. Although not shown in the diagram, the size of the liquid crystal layer 311 in the XY plane is also equal to the size of the transparent substrate T11 in the XY plane.

[0050] The power generation element E11 has a width WE1 in the first direction X. The width WE1 is approximately equal to the width WT1 of the transparent substrate T11. The power generation element E11 has a width WE2 in the third direction Z. The width WE2 is approximately equal to the thickness TT of the transparent substrate T11. The power generation element E11 has a thickness TE in the second direction Y. The thickness TE is, for example, approximately 3 mm.

[0051] The power generation element E11 is formed using, for example, an opaque substrate. However, by providing the power generation element E11 on the side surface SS1, the thinner surface of the power generation element E11 can be positioned parallel to the XY plane, thereby maintaining a high transmittance of the solar cell C11. Furthermore, the sizes of the components of solar cell C21 and C31 are equivalent to those of the components of solar cell C11.

[0052] According to this embodiment, the solar cell device 100 is constructed by connecting multiple solar cells, each consisting of a transparent substrate of a desired size and a power generation element as a single unit. That is, the size of the transparent substrate can be reduced, and the light guidance distance within the transparent substrate can be shortened. In addition, the number of times the light guided through the transparent substrate undergoes total internal reflection can be reduced. As a result, problems such as scattering or leakage of guided light due to foreign matter or minute cracks adhering to the transparent substrate and liquid crystal layer are suppressed. Consequently, losses when guiding light from the transparent substrate to the power generation element are suppressed, and a decrease in power generation efficiency is suppressed. Furthermore, the area of ​​the solar cell device 100 can be increased while suppressing a decrease in power generation efficiency.

[0053] Figure 5 is a plan view showing a modified example of the first embodiment. The configuration of the solar cell device 100 shown in Figure 5 differs from the configuration of the solar cell device 100 shown in Figure 4 in that multiple solar cells are arranged in a matrix in the first direction X and the second direction Y.

[0054] The solar cell device 100 comprises solar cells C11, C12, C13, C21, C22, C23, C31, C32, and C33, and an adhesive layer AD that bonds these multiple solar cells to each other.

[0055] Solar cells C11, C12, and C13 are arranged in this order in the first direction X. Solar cells C21, C22, and C23 are arranged in this order in the first direction X. Solar cells C31, C32, and C33 are arranged in this order in the first direction X. Solar cells C11, C21, and C31 are arranged in this order in the second direction Y. Solar cells C12, C22, and C32 are arranged in this order in the second direction Y. Solar cells C13, C23, and C33 are arranged in this order in the second direction Y.

[0056] Solar cell (third solar cell) C12 comprises a transparent substrate (third transparent substrate) T12 and a power generation element E12 bonded to the transparent substrate T12. Solar cell C13 comprises a transparent substrate T13 and a power generation element E13 bonded to the transparent substrate T13. Solar cell C22 comprises a transparent substrate T22 and a power generation element E22 bonded to the transparent substrate T22. Solar cell C23 comprises a transparent substrate T23 and a power generation element E23 bonded to the transparent substrate T23. Solar cell C32 comprises a transparent substrate T32 and a power generation element E32 bonded to the transparent substrate T32. Solar cell C33 comprises a transparent substrate T33 and a power generation element E33 bonded to the transparent substrate T33.

[0057] Solar cells C12, C13, C22, C23, C32, and C33 have the same configuration as solar cell C11. Solar cells C12, C13, C22, C23, C32, and C33 have a liquid crystal layer in a position that overlaps with their respective transparent substrates, but this is not shown in the illustration.

[0058] The adhesive layer AD bonded the transparent substrates T11 and T12, T12 and T13, T21 and T22, T22 and T23, T31 and T32, and T32 and T33.

[0059] Furthermore, the adhesive layer AD bonds the power generation element E11 to the transparent substrate T21, the power generation element E21 to the transparent substrate T31, the power generation element E12 to the transparent substrate T22, the power generation element E22 to the transparent substrate T32, the power generation element E13 to the transparent substrate T23, and the power generation element E23 to the transparent substrate T33. The adhesive layer AD is formed from a transparent or opaque resin. For example, the adhesive layer AD is formed from a silicone resin.

[0060] As shown in Figure 5, the area of ​​the solar cell device 100 can be further increased by arranging multiple solar cells in a matrix. The same effects as in the first embodiment can be obtained with the configuration shown in Figure 5.

[0061] [Second Embodiment] Figure 6 is a schematic cross-sectional view showing the solar cell C11 of the second embodiment. The configuration of solar cell C11 shown in Figure 6 differs from that of solar cell C11 shown in Figure 1 in that the power generation element E11 is located on the first main surface F1.

[0062] The power generation element E11 is bonded to the transparent substrate T11. In the second embodiment, the power generation element E11 is bonded to the first main surface F1. The light-receiving surface RS of the power generation element E11 faces the first main surface F1. Although not shown in the figures, the adhesive used to bond the transparent substrate T11 and the light-receiving surface RS is transparent and preferably has the same refractive index as the transparent substrate T11. For example, a UV-curing acrylic adhesive can be used.

[0063] Similar to the first embodiment, the light LTr guided by total internal reflection reaches the light-receiving surface RS of the power generation element E11, and the power generation element E11 generates electricity. The light LTr undergoes total internal reflection due to the difference in refractive index between the transparent substrate T11 and air, but at the location where the power generation element E11 is provided, there is almost no difference in refractive index between the transparent substrate T11 and the power generation element E11, so the light LTr travels towards the power generation element E11.

[0064] Figure 7 is a schematic diagram showing the solar cell apparatus 100 of the second embodiment. Figure 7(a) is a cross-sectional view showing the solar cell apparatus 100 along the YZ plane. Figure 7(b) is a plan view showing the solar cell apparatus 100 along the XY plane. The configuration of the solar cell apparatus 100 shown in Figure 7 differs from the configuration of the solar cell apparatus 100 shown in Figure 4 in that the positions of the power generation elements E11, E21, and E31 are different.

[0065] The power generation element E21 is bonded to the transparent substrate T21. In the second embodiment, the power generation element E21 is bonded to the third main surface F3. The power generation element E21 has a light-receiving surface facing the third main surface F3.

[0066] Transparent substrates T11 and T21 are bonded to each other by an adhesive layer AD1. More specifically, side surfaces SS1 and SS2 are bonded to each other by the adhesive layer AD1.

[0067] The power generation element E31 is bonded to the transparent substrate T31. In the second embodiment, the power generation element E31 is bonded to the fifth main surface F5. The power generation element E31 has a light-receiving surface facing the fifth main surface F5.

[0068] Transparent substrates T21 and T31 are bonded to each other by adhesive layer AD2. More specifically, side surfaces SS3 and SS4 are bonded to each other by adhesive layer AD2.

[0069] The power generation element E11 has a width WE2 in the second direction Y. The width WE2 is, for example, approximately 10 mm. The width of the power generation elements E21 and E31 in the second direction Y is also equivalent to the width WE2.

[0070] According to the second embodiment, the power generation elements E11, E21, and E31 are arranged on the main surfaces of the transparent substrates T11, T21, and T31, respectively. Therefore, in the manufacturing process, the power generation elements E11, E21, and E31 can be attached after the transparent substrates T11, T21, and T31 have been bonded together by adhesive layers AD1 and AD2. Thus, the manufacturing process can be simplified. In addition, since the transparent substrates are bonded together by adhesive layers, the strength of the solar cell device 100 can be increased.

[0071] Figure 8 is a plan view showing a modified example of the second embodiment. The configuration of the solar cell device 100 shown in Figure 8 differs from the configuration of the solar cell device 100 shown in Figure 7 in that multiple solar cells are arranged in a matrix in the first direction X and the second direction Y. Furthermore, the configuration of the solar cell device 100 shown in Figure 8 differs from the configuration of the solar cell device 100 shown in Figure 5 in that the position of the power generation elements is different.

[0072] Adhesive layer AD bonds transparent substrates T11 and T12, transparent substrates T12 and T13, transparent substrates T21 and T22, transparent substrates T22 and T23, transparent substrates T31 and T32, and transparent substrates T32 and T33. Adhesive layer AD also bonds transparent substrates T11 and T21, transparent substrates T21 and T31, transparent substrates T12 and T22, transparent substrates T22 and T32, transparent substrates T13 and T23, and transparent substrates T23 and T33.

[0073] As shown in Figure 8, the area of ​​the solar cell device 100 can be further increased by arranging multiple solar cells in a matrix. The same effects as those of the first and second embodiments can be obtained with the configuration shown in Figure 8.

[0074] [Third Embodiment] Figure 9 is a schematic diagram showing the solar cell apparatus 100 of the third embodiment. The configuration of the solar cell apparatus 100 shown in Figure 9 differs from that of the solar cell apparatus 100 shown in Figure 8 in the positions of the power generation elements E21, E22, and E23. The arrows in the figure indicate the direction of light guidance.

[0075] The power generation element E11 is bonded to the end of the transparent substrate T11 that is on the side of the transparent substrate T21. The power generation element E21 is bonded to the end of the transparent substrate T21 that is on the side of the transparent substrate T11. The power generation element E12 is bonded to the end of the transparent substrate T12 that is on the side of the transparent substrate T22. The power generation element E22 is bonded to the end of the transparent substrate T22 that is on the side of the transparent substrate T12. The power generation element E13 is bonded to the end of the transparent substrate T13 that is on the side of the transparent substrate T23. The power generation element E23 is bonded to the end of the transparent substrate T23 that is on the side of the transparent substrate T13.

[0076] According to the third embodiment, solar cells C11, C12, C13, C31, C32, and C33 that guide light in the positive direction of the second direction Y are arranged in combination with solar cells C21, C22, and C23 that guide light in the negative direction of the second direction Y. In this case, the light guiding efficiency due to differences in the angle of incident light can be averaged out, enabling stable power generation regardless of the installation conditions.

[0077] [Fourth Embodiment] Figure 10 is a schematic diagram showing the solar cell apparatus 100 of the fourth embodiment. The configuration of the solar cell apparatus 100 shown in Figure 10 differs from the configuration of the solar cell apparatus 100 shown in Figure 8 in the shape of the outer edge of the solar cell apparatus 100.

[0078] In the example shown in Figure 10, solar cell C11 is not present, and solar cells C24 and C34 are present, compared to the example shown in Figure 8. Solar cell C24 is adjacent to solar cell C23 in the first direction X. Solar cell C34 is adjacent to solar cell C33 in the first direction X.

[0079] According to the fourth embodiment, the outer edge of the area where multiple solar cells are arranged is not rectangular. In other words, solar cells can be appropriately combined according to the shape of the window glass or building, thus expanding the options for installation locations. Solar cell devices 100 can be formed in various shapes, such as rectangular, circular, or polygonal, as shown in Figure 5.

[0080] [Fifth Embodiment] Figure 11 is a schematic diagram showing the solar cell apparatus 100 of the fifth embodiment. Figure 11(a) is a plan view showing the solar cell apparatus 100. Figure 11(b) is a diagram showing the electrical connection relationships of the power generation elements.

[0081] As shown in Figure 11(a), the solar cell device 100 comprises a plurality of solar cells CA arranged in a matrix in a first direction X and a second direction Y. The plurality of solar cells CA are arranged in m rows and n columns. Each of the plurality of solar cells CA is equipped with a power generation element EA.

[0082] As shown in Figure 11(b), multiple power generation elements EA arranged in the first direction X are electrically connected in series. In the same row, multiple power generation elements EA connected in series are referred to as a single power generation element group GR. Each power generation element group GR is connected to the power supply voltage V.

[0083] According to the fifth embodiment, multiple power generation elements EA located in the same row are electrically connected in series. In the case of series connection, the output voltage of one row is equivalent to the sum of the voltages of each power generation element EA, so a higher voltage can be obtained. In the case of series connection, the output current of one row is equal to the current of each power generation element EA.

[0084] [Sixth Embodiment] Figure 12 is a schematic diagram showing the solar cell apparatus 100 of the sixth embodiment. Figure 12(a) is a plan view showing the solar cell apparatus 100. Figure 12(b) is a diagram showing the electrical connection relationships of the power generation elements. Note that Figure 12(a) is the same as Figure 11(a).

[0085] As shown in Figure 12(b), multiple power generation elements EA arranged in the first direction X are electrically connected in series. In the same row, multiple power generation elements EA connected in series are referred to as a single power generation element group GR. The power generation element group GR arranged in the second direction Y are electrically connected in series with each other. The series-connected power generation element group GR is connected to the power supply voltage V.

[0086] According to the sixth embodiment, multiple power generation elements EA are electrically connected in series across rows. In the case of series connection, the output voltage is equivalent to the sum of the voltages of each power generation element EA, so a higher voltage can be obtained than in the fifth embodiment. In the case of series connection, the output current is equal to the current of each power generation element EA.

[0087] [Seventh Embodiment] Figure 13 is a schematic diagram showing the solar cell apparatus 100 of the seventh embodiment. Figure 13(a) is a plan view showing the solar cell apparatus 100. Figure 13(b) is a diagram showing the electrical connection relationships of the power generation elements. Note that Figure 13(a) is the same as Figure 11(a).

[0088] As shown in Figure 13(b), multiple power generation elements EA arranged in the first direction X are electrically connected in series. In the same row, multiple power generation elements EA connected in series are referred to as a single power generation element group GR. The power generation element group GR arranged in the second direction Y are electrically connected in parallel to each other. The parallel-connected power generation element group GR is connected to the power supply voltage V.

[0089] According to the seventh embodiment, multiple power generation elements EA located in the same row are electrically connected in series. In the case of series connection, the output voltage of one row corresponds to the sum of the voltages of each power generation element EA, so a higher voltage can be obtained. In addition, the power generation element group GR is electrically connected in parallel with each other. In the case of parallel connection, the output current corresponds to the sum of the currents of each power generation element group GR, so a higher current can be obtained.

[0090] [Eighth Embodiment] Figure 14 is a schematic diagram showing the solar cell apparatus 100 of the eighth embodiment. The configuration of the solar cell apparatus 100 shown in Figure 14 differs from the configuration of the solar cell apparatus 100 shown in Figure 8 in the number of power generation elements.

[0091] In the illustrated example, the power generation elements E11 and E12 correspond to the transparent substrates T11, T12, and T13. Solar cell C12 shares the power generation element E11 of solar cell C11 and the power generation element E12 of solar cell C13. Furthermore, power generation elements E21 and E22 correspond to transparent substrates T21, T22, and T23. Solar cell C22 shares power generation element E21 with solar cell C21 and power generation element E22 with solar cell C23. Furthermore, power generation elements E31 and E32 correspond to transparent substrates T31, T32, and T33. Solar cell C32 shares power generation element E31 with solar cell C31 and power generation element E32 with solar cell C33.

[0092] As shown in Figure 14, the number of rows of the transparent substrate and the number of rows of the power generation elements do not necessarily have to be the same; the number of rows of the transparent substrate may be greater than the number of rows of the power generation elements. In this case, the width WE1 of each power generation element in the first direction X is greater than the width WT1 of each transparent substrate in the first direction X.

[0093] [Ninth Embodiment] Figure 15 is a schematic diagram showing the solar cell apparatus 100 of the ninth embodiment. The configuration of the solar cell apparatus 100 shown in Figure 15 differs from the configuration of the solar cell apparatus 100 shown in Figure 8 in the number of power generation elements.

[0094] Solar cell C11 has power generation elements E11 and E12. Solar cell C12 has power generation elements E13 and E14. Solar cell C13 has power generation elements E15 and E16. Solar cell C21 has power generation elements E21 and E22. Solar cell C22 has power generation elements E23 and E24. Solar cell C23 has power generation elements E25 and E26. Solar cell C31 has power generation elements E31 and E32. Solar cell C32 has power generation elements E33 and E34. Solar cell C33 has power generation elements E35 and E36.

[0095] As shown in Figure 15, the number of rows of the transparent substrate and the number of rows of the power generation elements do not necessarily have to be the same; the number of rows of power generation elements may be greater than the number of rows of the transparent substrate. In this case, the width WE1 of each power generation element in the first direction X is smaller than the width WT1 of each transparent substrate in the first direction X.

[0096] As described above, according to this embodiment, a solar cell device capable of suppressing light loss during light guidance can be obtained.

[0097] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0098] 100...Solar cell device, C11, C12, C13, C21, C22, C23, C31, C32, C33, CA...Solar cell, F1...First main surface, F2...Second main surface, F3...Third main surface, F4...Fourth main surface, T11, T12, T13, T21, T22, T23, T31, T32, T33...Transparent substrate, E11, E12, E13, E21, E22, E23, E31, E32, E33, EA...Power generation element 31...Cholesteric liquid crystal, 311, 321, 331...Liquid crystal layer, AD, AD1, AD2... Adhesive layer, GR... Group of power generation elements. SS1, SS2, SS3, SS4, SS5... side view.

Claims

1. A first transparent substrate having a first main surface, a second main surface facing the first main surface, and a first side surface, A first power generation element bonded to the first side surface of the first transparent substrate, A first liquid crystal layer having a cholesteric liquid crystal containing a plurality of liquid crystal molecules, which is arranged on the side of the second main surface, A first solar cell having, A second transparent substrate having a third main surface, a fourth main surface facing the third main surface, a second side surface facing the first side surface, and a third side surface facing the second side surface, A second power generation element is bonded to the third side surface of the second transparent substrate, A second liquid crystal layer having a cholesteric liquid crystal containing a plurality of liquid crystal molecules, which is located on the side of the fourth main surface, A second solar cell having, A first adhesive layer that bondes the first solar cell and the second solar cell to each other, A third transparent substrate having a fifth main surface, a sixth main surface facing the fifth main surface, a fourth side surface facing the third side surface, and a fifth side surface facing the fourth side surface, A third power generation element bonded to the fifth side surface of the third transparent substrate, A third liquid crystal layer having a cholesteric liquid crystal containing a plurality of liquid crystal molecules, which is located on the side of the sixth main surface, A third solar cell having, A second adhesive layer that bondes the second solar cell and the third solar cell to each other, Equipped with, The first power generation element is positioned between the first side surface and the second side surface. The first power generation element is positioned between the first side surface and the first adhesive layer. The second power generation element is positioned between the third side and the fourth side, The second power generation element is positioned between the third side surface and the second adhesive layer. The first solar cell, the second solar cell, and the third solar cell are arranged in a line along the first direction. A solar cell device in which the first, second, third, fourth, and fifth sides extend along a second direction intersecting the first direction and are arranged in a line along the first direction.

2. A fourth transparent substrate having a seventh main surface, an eighth main surface opposite the seventh main surface, a sixth side surface extending along the second direction, and an eighth side surface extending along the first direction, A fourth power generation element is bonded to the sixth side surface of the fourth transparent substrate, A fourth liquid crystal layer having a cholesteric liquid crystal containing a plurality of liquid crystal molecules, which is located on the side of the eighth main surface, A fourth solar cell having the following characteristics is further provided: The first solar cell has a seventh surface extending along the first direction, The fourth solar cell is aligned with the first solar cell in the second direction, The solar cell apparatus according to claim 1, wherein the seventh side surface of the first solar cell and the eighth side surface of the fourth solar cell are bonded together by a third adhesive layer disposed between the seventh and eighth side surfaces.

3. The system comprises a plurality of solar cells, including the first solar cell, the second solar cell, and the third solar cell. The solar cell apparatus according to claim 1, wherein the outer edge of the region in which the plurality of solar cells are arranged is not rectangular in shape.

4. The system comprises a plurality of solar cells, including the first solar cell, the second solar cell, and the third solar cell. Multiple solar cells are arranged in a matrix in the first direction and in a second direction intersecting the first direction, and each is equipped with a power generation element. The plurality of power generation elements arranged in the first direction are electrically connected in series to form a group of power generation elements. The solar cell apparatus according to claim 1, wherein each of the power generation elements is connected to a power supply voltage.

5. The system comprises a plurality of solar cells, including the first solar cell, the second solar cell, and the third solar cell. Multiple solar cells are arranged in a matrix in the first direction and in a second direction intersecting the first direction, and each is equipped with a power generation element. The plurality of power generation elements arranged in the first direction are electrically connected in series to form a group of power generation elements. The solar cell apparatus according to claim 1, wherein the group of power generation elements arranged in the second direction are electrically connected in series.

6. The system comprises a plurality of solar cells, including the first solar cell, the second solar cell, and the third solar cell. Multiple solar cells are arranged in a matrix in the first direction and in a second direction intersecting the first direction, and each is equipped with a power generation element. The plurality of power generation elements arranged in the first direction are electrically connected in series to form a group of power generation elements. The solar cell apparatus according to claim 1, wherein the group of power generation elements arranged in the second direction are electrically connected in parallel.

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