Solar battery

Abstract

To provide a solar battery that can be suppressed in reduction of photoelectric conversion efficiency and furthermore can be reduced in thickness .SOLUTION: A solar battery 10 comprises an optical member 30 which has a first surface 31 and a second surface 32 located on the opposite side from the first surface 31, and a cell constitution part 20 which is provided on the side of the second surface 32 of the optical member 30. A plurality of projection parts 37 are formed on the second surface 32 of the optical member 30. Each of the projection parts 37 extends along a first direction d1, and is arrayed along a second direction d2 orthogonal to the first direction d1. The thickness T of the cell constitution part 20 is less than the height H of the projection parts 37. The cell constitution part 20 gets into between projection parts 37.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to solar cells. [Background technology]

[0002] Photovoltaic power generation is known as a power generation method that places little strain on the environment. Solar cells are used for this type of power generation. Solar cells are cells that convert light into electricity. Known types of solar cells include inorganic solar cells and organic solar cells. Of these, organic solar cells have the advantage of low manufacturing costs. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-192265 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional solar cells are not sufficiently thin. Furthermore, when conventional solar cells are made thinner, the components that convert light into electricity become thinner. When the components that convert light into electricity are made thinner, the components may not absorb enough light. In this case, the photoelectric conversion efficiency of the solar cell decreases.

[0005] The present disclosure has been made in consideration of the above points, and aims to provide a solar cell that can reduce the thickness of the solar cell while suppressing a decrease in photoelectric conversion efficiency. [Means for solving the problem]

[0006] The solar cell of the present disclosure comprises: an optical member having a first surface and a second surface located opposite the first surface; a cell component provided on the second surface side of the optical member, a plurality of convex portions are formed on the second surface of the optical member; Each of the protrusions extends along a first direction and is arranged along a second direction perpendicular to the first direction, the thickness of the cell constituent portion is smaller than the height of the protrusion, The cell constituent portions are embedded between the protrusions. [Effects of the Invention]

[0007] According to the present disclosure, the thickness of a solar cell can be reduced while suppressing a decrease in photoelectric conversion efficiency. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view showing a solar power generation system according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view (cross-sectional view taken along line II-II in FIG. 1) showing a solar power generation system according to an embodiment. [Figure 3] FIG. 3 is a perspective view showing an optical member according to an embodiment. [Figure 4] FIG. 4 is a cross-sectional view (cross-sectional view taken along line IV-IV in FIG. 2) showing the solar cell according to the embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing the optical path of light incident on a solar cell. [Figure 6] FIG. 6 is a cross-sectional view showing a modified example of the solar cell according to the embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing a modified example of the solar power generation system according to the embodiment. [Figure 8] FIG. 8 is a perspective view showing an optical member according to an embodiment. [Figure 9] FIG. 9 is a cross-sectional view (cross-sectional view taken along line IX-IX in FIG. 8) showing an optical member according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present disclosure will be described below with reference to the drawings. In the drawings accompanying this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the sake of ease of illustration and understanding. Configurations shown in some drawings may be omitted in other drawings.

[0010] In this specification, terms specifying shapes or geometric conditions, and the degree of shapes, etc., such as "parallel," "orthogonal," and "same," or values ​​of lengths or angles, etc., are not limited to their strict meanings but are interpreted to include a range of degrees within which similar functions can be expected.

[0011] In this specification, the normal direction of a plate-like member refers to the normal direction to the plate surface of the target plate-like member. The "plate surface" refers to the surface that coincides with the target plate-like member when the target plate-like member is viewed overall and globally.

[0012] In this specification, terms such as "sheet," "film," and "plate" are not distinguished from one another solely on the basis of differences in name. For example, a "sheet" cannot be distinguished from a member called a film or a plate solely on the basis of differences in name.

[0013] In this specification, when multiple upper limit value candidates and multiple lower limit value candidates are listed for a parameter, the parameter may be a numerical range that combines any one upper limit value candidate and any one lower limit value candidate.

[0014] An embodiment of the present disclosure relates to the following [1] to [6].

[0015] [1] an optical member having a first surface and a second surface located opposite the first surface; a cell component provided on the second surface side of the optical member, a plurality of convex portions are formed on the second surface of the optical member; Each of the protrusions extends along a first direction and is arranged along a second direction perpendicular to the first direction, the thickness of the cell constituent portion is smaller than the height of the protrusion, The solar cell, wherein the cell component is embedded between the protrusions.

[0016] [2] The solar cell according to [1], wherein the convex portion constitutes a lenticular lens.

[0017] [3] The solar cell according to [1] or [2], wherein a plurality of prism portions are formed on the first surface.

[0018] [4] each of the prism portions includes, in a cross section perpendicular to the second direction, a first inclined surface facing one side of the first direction, and a second inclined surface facing the other side of the first direction in a cross section perpendicular to the second direction; The solar cell according to [3], wherein the first inclined surface is larger than the second inclined surface.

[0019] [5] The solar cell according to any one of [1] to [4], wherein the cell component contains a perovskite compound.

[0020] [6] The solar cell according to any one of [1] to [5], further comprising a diffuse reflection sheet provided on the opposite side of the cell component from the optical member side.

[0021] Next, an embodiment of the present disclosure will be described with reference to Fig. 1 to Fig. 5. The solar power generation system 1 is a system that supplies electric power when irradiated with light. That is, the solar power generation system 1 is a system that converts light energy into electric energy. Note that the solar power generation system 1 can supply electric power not only from sunlight but also from illumination light, image light, or the like.

[0022] 1, the solar power generation system 1 includes a substrate 3, a circuit 5, and a plurality of solar cells 10. The solar power generation system 1 is configured to supply power generated by irradiating the solar cells 10 with light via the circuit 5 to a device that consumes the power (not shown) or a storage battery (not shown) that stores the power.

[0023] The substrate 3 of the solar power generation system 1 is a member for supporting the circuit 5 and the solar cell 10. This substrate 3 may be a plate-shaped member. The thickness of the substrate 3 may be 1 μm or more, 25 μm or more, 10 mm or less, or 500 μm or less. The substrate 3 is made of an insulator. The material of the substrate 3 may be an inorganic material such as glass. The material of the substrate 3 may be a plastic material such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, cycloolefin polymer, or polyimide. The material of the substrate 3 may also be a composite material such as a nanocomposite.

[0024] The circuit 5 electrically connects the solar cells 10 to each other. The circuit 5 also electrically connects the solar cells 10 to a device that consumes power (not shown) or a storage battery (not shown) that stores power. In this way, the power generated by the solar cells 10 is configured to be transmitted to an external device or the like via the circuit 5.

[0025] 1, the circuit 5 extends linearly in a plan view. The circuit 5 is made of a conductive material such as copper. The circuit 5 may include a diode (not shown) for bypassing the solar cell 10 that is no longer able to generate power due to shadowing, a malfunction, or the like.

[0026] As shown in Figures 1 and 2, the circuit 5 includes a first connection portion 6 and a second connection portion 7 between the solar cells 10. The first connection portion 6 and the second connection portion 7 are connected to each other. Between the solar cells 10, the first connection portion 6 is connected to a first electrode layer 21 (described later) of one of the solar cells 10. Between the solar cells 10, the second connection portion 7 is connected to a second electrode layer 22 (described later) of the other solar cell 10. In this way, the first connection portion 6 and the second connection portion 7 connect the solar cells 10 adjacent to each other.

[0027] As shown in FIG. 1, a plurality of solar cells 10 are regularly arranged two-dimensionally. In the illustrated example, the solar cells 10 are arranged along a first direction d1 and a second direction d2. The second direction d2 is a direction non-parallel to the first direction d1. The second direction d2 may be a direction perpendicular to the first direction d1. In a plan view, the area of ​​one solar cell 10 is 400 mm 2 It may be the following.

[0028] As shown in Fig. 2, the solar cell 10 includes an optical member 30 having a first surface 31 and a second surface 32 located on the opposite side of the first surface 31, and a cell component 20 provided on the second surface 32 side of the optical member 30. In this embodiment, the first surface 31 of the optical member 30 forms the incident surface 11 of the solar cell 10. The optical member 30 and the cell component 20 are arranged in this order from the incident surface 11 side along a third direction d3. The third direction d3 may be a direction perpendicular to both the first direction d1 and the second direction d2, or may be a normal direction to the substrate 3.

[0029] The optical member 30 of the solar cell 10 is a member for changing the traveling direction of light that passes through it. Specifically, the optical member 30 is a member for lengthening the range of light within the cell component 20.

[0030] 3, the optical member 30 has a main body 33 and a plurality of convex portions 37 located closer to the second surface 32 than the main body 33. In this embodiment, the plurality of convex portions 37 are formed on the second surface 32.

[0031] The main body 33 of the optical member 30 supports the protrusion 37. The main body 33 is in the shape of a flat plate.

[0032] 3 and 4, each of the protrusions 37 extends along a first direction d1. The protrusions 37 are also arranged along a second direction d2 that is perpendicular to the first direction d1. In the example shown in FIGS. 3 and 4, six protrusions 37 are arranged, but the number of protrusions 37 is not limited to this.

[0033] In this embodiment, the convex portions 37 form lenticular lenses. As shown in FIG. 4, the cross-sectional shape of the convex portions 37 is substantially semi-elliptical in a cross section perpendicular to the first direction d1. The cross-sectional shape of the convex portions 37 may be any shape that appropriately changes the traveling direction of transmitted light. The cross-sectional shape of the convex portions 37 may be determined based on the difference between the refractive index of the convex portions 37 and the refractive index of the cell constituent portion 20. The refractive index of the convex portions 37 may be 1.45 or more, or 1.95 or less.

[0034] The height H of the protrusion 37 (length in the third direction d3 (see FIG. 4)) may be, for example, 0.01 mm or more and 10 mm or less. The height H of the protrusion 37 refers to the distance from a position P of the protrusion 37 that is farthest from the main body 33 to the main body 33 in the normal direction of the substrate 3 (thickness direction of the main body 33 (third direction d3)).

[0035] In such an optical element 30, the refractive index of the main body 33 and the convex portion 37 may be the same to avoid the formation of a reflective interface between the main body 33 and the convex portion 37. The main body 33 and the convex portion 37 may be formed from the same material. Furthermore, the main body 33 and the convex portion 37 may be integrally formed. The material of the optical element 30 may be an organic material, such as glass. For example, the material of the optical element 30 may be polycarbonate, polyethylene terephthalate, cycloolefin polymer, acrylic, or epoxy, or a mixture of these with a filler made of a high refractive index material. The filler may be an organic filler or an inorganic filler. Furthermore, the filler may be a metal filler or a low refractive index material.

[0036] The refractive index values ​​are measured using an Abbe refractometer (for example, the RX-7000α manufactured by Atago Co., Ltd.) The magnitude relationship between the refractive indices is confirmed by the refraction direction of light incident on the interface between the materials whose refractive indices are being compared and the total reflection conditions.

[0037] The optical element 30 may be transparent so as to allow light to pass through. Specifically, the visible light transmittance of the optical element 30 may be 80% or more, or even 90% or more. In this specification, the visible light transmittance refers to the transmittance in the normal direction of the substrate 3 (the thickness direction (third direction d3) of the optical element 30). The visible light transmittance is determined as the average value of the total light transmittance at each wavelength measured at 1-nm intervals within a wavelength range of 380 nm to 780 nm using a spectrophotometer. In this case, the spectrophotometer used is the "UV-3600i Plus" manufactured by Shimadzu Corporation (compliant with JIS K0115). The test piece for measuring the visible light transmittance is a flat plate cut out of the optical element 30 so that the thickness of the optical element 30 is 1 mm. At this time, no protrusions 37 remain on the test piece. The angle of incidence when measuring the visible light transmittance is set to 0° unless a specific transmission direction is specified. The incident angle is the angle formed by the direction of propagation of incident light relative to the thickness direction of the solar cell 10, and is a value less than 90°.

[0038] The optical member 30 may transmit not only visible light but also ultraviolet light with a wavelength of 300 nm or more and 400 nm or less and / or infrared light with a wavelength of 750 nm or more and 1400 nm or less. Specifically, the optical member 30 may have a transmittance of 80% or more, or even 90% or more, for ultraviolet light with a wavelength of 300 nm or more and 400 nm or less. Furthermore, the optical member 30 may have a transmittance of 80% or more, or even 90% or more, for infrared light with a wavelength of 750 nm or more and 1400 nm or less. The thickness of the optical member 30 may be 5 μm or more and 300 μm or less.

[0039] Next, the cell configuration unit 20 will be described.

[0040] The cell component 20 is a layer for generating electric power using light transmitted through the optical member 30. The cell component 20 may generate electric power not only using sunlight but also using illumination light, image light, or the like. The cell component 20 is in the form of a thin film. As will be described later, the cell component 20 may include a perovskite compound.

[0041] 2, the cell component 20 is disposed on the substrate 3. The cell component 20 has, in this order from the incident surface 11 side of the solar cell 10, a first electrode layer 21, a first carrier transport layer 23, a power generation layer 25, a second carrier transport layer 24, and a second electrode layer 22. Here, the first electrode layer 21 and the second electrode layer 22 will first be described.

[0042] The first electrode layer 21 is a layer for extracting electrons that have moved from the power generation layer 25. The second electrode layer 22 is a layer for extracting holes that have moved from the power generation layer 25. By extracting electrons and holes using the first electrode layer 21 and the second electrode layer 22, the power generated in the power generation layer 25 can be transmitted to the outside. The first electrode layer 21 and the second electrode layer 22 are arranged opposite each other. The power generation layer 25 is arranged between the first electrode layer 21 and the second electrode layer 22. Note that the first electrode layer 21 may be a layer for extracting holes that have moved from the power generation layer 25, and the second electrode layer 22 may be a layer for extracting electrons that have moved from the power generation layer 25. In the following description, the first electrode layer 21 is a layer for extracting electrons that have moved from the power generation layer 25, and the second electrode layer 22 is a layer for extracting holes that have moved from the power generation layer 25, and specific values, shapes, materials, etc. will be given. On the other hand, when the first electrode layer 21 is a layer for extracting holes that have moved from the power generation layer 25 and the second electrode layer 22 is a layer for extracting electrons that have moved from the power generation layer 25, the specific values, shapes, materials, etc. can be changed as appropriate.

[0043] The first electrode layer 21 and the second electrode layer 22 may be transparent. Specifically, the visible light transmittance of the first electrode layer 21 and the second electrode layer 22 may be 75% or more, or 85% or more.

[0044] The thickness of the first electrode layer 21 and the second electrode layer 22 may be 5 nm or more, or 150 nm or less. The first electrode layer 21 and the second electrode layer 22 may be made of indium tin oxide (ITO), silver nanowires, polythiophene, or a film including a copper mesh.

[0045] Next, the first carrier transport layer 23 and the second carrier transport layer 24 will be described.

[0046] The first carrier transport layer 23 and the second carrier transport layer 24 are layers for improving the photoelectric conversion efficiency of the cell component 20. Specifically, the first carrier transport layer 23 is a layer for efficiently transporting electrons from the power generation layer 25 to the first electrode layer 21. The first carrier transport layer 23 is disposed between the power generation layer 25 and the first electrode layer 21. The second carrier transport layer 24 is a layer for efficiently transporting holes from the power generation layer 25 to the second electrode layer 22. The second carrier transport layer 24 is disposed between the power generation layer 25 and the second electrode layer 22.

[0047] The first carrier transport layer 23 and the second carrier transport layer 24 may be transparent. Specifically, the visible light transmittance of the first carrier transport layer 23 and the second carrier transport layer 24 may be 95% or more, or 98% or more. The thickness of the first carrier transport layer 23 may be 0.005 μm or more and 0.120 μm or less. The thickness of the second carrier transport layer 24 may be 0.050 μm or more and 0.2 μm or less. The material of the first carrier transport layer 23 may be titanium oxide or tin oxide. The material of the second carrier transport layer 24 may be Spiro-OMeTAD or copper thiocyanate.

[0048] Next, the power generation layer 25 will be described.

[0049] The power generation layer 25 is a layer for exciting electrons and holes therein by absorbing light. The electrons excited in the power generation layer 25 move toward the first electrode layer 21. On the other hand, the holes excited in the power generation layer 25 move toward the second electrode layer 22. In this way, the movement of electrons and holes generates electricity. In this way, the power generation layer 25 converts light into electricity.

[0050] The power generation layer 25 includes an organic material. The power generation layer 25 may include a perovskite compound. A perovskite compound is a semiconductor compound having a perovskite structure. A perovskite structure generally refers to a crystal structure expressed by the composition AMX3, such as perovskite (CaTiO3; perovskite). Perovskite compounds can have various compositions depending on the type of ligand and central metal. To increase photoelectric conversion efficiency, the power generation layer 25 including a perovskite compound may also contain lead. Examples of perovskite compounds include CH3NH3PbI3, CH(NH2)2PbI3, and Cs 0.05 (FA 0.85 MA 0.15 ) 0.95 Pb(I 0.89 Br 0.11 )3, Cs 0.1 FA 0.6 MA 0.3 Sn 0.5 Pb 0.5 The power generation layer 25 may be made of a high-purity perovskite-type compound. Specifically, the power generation layer 25 may contain 98% by mass or more, or 99% by mass or more, of the perovskite-type compound.

[0051] The power generation layer 25 containing an organic material may generate electricity by absorbing visible light with a wavelength of 410 nm or more and 700 nm or less, for example. The power generation layer 25 containing an organic material can also generate electricity using light with lower illuminance than sunlight, such as illumination light or image light. Compared to a power generation layer containing an inorganic material such as silicon, the power generation layer 25 containing an organic material is more likely to generate electricity using light incident from a direction oblique to the thickness direction of the power generation layer 25. The power generation layer 25 may be transparent. Specifically, the visible light transmittance of the power generation layer 25 may be 10% or more, or 30% or more.

[0052] The thickness of the power generation layer 25 may be 0.05 μm or more, 100 μm or less, or 0.5 μm or less. The power generation layer 25 absorbs light (visible light). Therefore, when the thickness of the power generation layer 25 is 100 μm or less, the transparency of the cell component 20 can be improved. Specifically, the visible light transmittance of the cell component 20 can be 10% or more, as described below.

[0053] Such a cell component 20 may further include other layers intended to perform specific functions, such as a protective sheet layer, a filler layer, a strength support layer, an antifouling layer, a light-blocking layer, or an adhesive layer.

[0054] As shown in FIG. 4, the thickness T (length in the third direction d3) of the cell constituent portion 20 is thinner than the height H of the convex portion 37 of the optical member 30. The thickness T of the cell constituent portion 20 refers to the distance from the inner surface 20a to the outer surface 20b of the cell constituent portion 20 in the portion covering the position P of the convex portion 37. Here, the inner surface 20a of the cell constituent portion 20 refers to the surface of the cell constituent portion 20 on the side of the incident surface 11 in a cross section perpendicular to the first direction d1. The outer surface 20b of the cell constituent portion 20 refers to the surface of the cell constituent portion 20 opposite to the incident surface 11 in a cross section perpendicular to the first direction d1.

[0055] Furthermore, the cell constituent portion 20 is embedded between the protrusions 37. In this case, the outer surface 20b of the cell constituent portion 20 extends along the second surface 32 of the optical member 30 so as to follow the second surface 32 of the optical member 30. This makes it easier for light L (see FIG. 5) incident on the incident surface 11 of the solar cell 10 to be totally reflected by the outer surface 20b of the cell constituent portion 20, as will be described later. The thickness T of the cell constituent portion 20 may be 0.05 μm or more, 100 μm or less, or 0.5 μm or less.

[0056] The cell constituent portion 20 may be transparent. The visible light transmittance of the cell constituent portion 20 may be 10% or more, or may be 30% or more.

[0057] The solar cell 10 may further include a layer (not shown) for converting the wavelength of incident light between the optical member 30 and the cell component 20. The solar cell 10 may further include a low-reflection layer (not shown) for suppressing reflection on the incident surface 11. In this case, the low-reflection layer may be provided on the optical member 30, or may form the incident surface 11 of the solar cell 10.

[0058] Next, an example of a method for manufacturing the solar power generation system 1 according to this embodiment will be described.

[0059] First, an optical member 30 having a plurality of convex portions 37 formed thereon is prepared. At this time, the optical member 30 may be produced by an ultraviolet (UV) shaping method, a casting method, a thermal shaping method, or the like. Alternatively, the optical member 30 may be produced by cutting out a resin material.

[0060] Next, on the convex portion 37 of the optical member 30, the first electrode layer 21, the first connection portion 6, the first carrier transport layer 23, the power generation layer 25, the second carrier transport layer 24, the second electrode layer 22, and the second connection portion 7 are provided.

[0061] The first electrode layer 21, the first connection portion 6, the first carrier transport layer 23, the second carrier transport layer 24, the second electrode layer 22, and the second connection portion 7 may each be formed by vacuum film formation such as vacuum deposition or sputtering. On the other hand, the power generation layer 25 may be produced by applying an organic material onto the first carrier transport layer 23. The first connection portion 6 is formed so as to be connected to the first electrode layer 21. The second connection portion 7 is formed so as to be connected to the second electrode layer 22 and the first connection portion 6.

[0062] Through the above steps, the solar cell 10 is fabricated.

[0063] Next, a plurality of solar cells 10 are arranged on the substrate 3. Thereafter, the solar cells 10 are connected to each other by circuits 5, and the solar power generation system 1 is manufactured.

[0064] In conventional solar cells, the thickness of the power generation layer included in the solar cell may be increased in order to increase the light absorption rate. In this case, the photoelectric conversion efficiency may decrease due to recombination of electrons and holes, etc. On the other hand, if the solar cell power generation layer is made thinner, the light absorption rate may decrease, and the photoelectric conversion efficiency of the solar cell may also decrease. As such, in conventional solar cells, it is difficult to reduce the thickness of the solar cell while suppressing a decrease in photoelectric conversion efficiency.

[0065] In contrast, in the present embodiment, the thickness T of the cell component 20 is thinner than the height H of the convex portions 37. By reducing the thickness of the cell component 20 in this manner, it is possible to suppress recombination of electrons and holes, etc., and therefore it is possible to suppress a decrease in photoelectric conversion efficiency. Furthermore, in the present embodiment, the thickness T of the cell component 20 is thinner than the height H of the convex portions 37, and the cell component 20 is embedded between the convex portions 37. In this case, as shown in FIG. 5 , light L incident on the incident surface 11 of the solar cell 10 is likely to be totally reflected by the outer surface 20b of the cell component 20. Therefore, the range of light within the cell component 20 (power generation layer 25) is longer. Thus, the longer the range (optical path) of light passing through the cell component 20 (power generation layer 25), the more easily the light is absorbed by the power generation layer 25. The light absorbed by the power generation layer 25 generates electricity. Therefore, in the solar cell 10 according to this embodiment, the photoelectric conversion efficiency of the power generation layer 25 can be improved. As a result, even when the cell component 20 (power generation layer 25) is thinned, it is possible to suppress a decrease in photoelectric conversion efficiency in the power generation layer 25. Therefore, in the solar cell 10 according to this embodiment, the thickness of the cell component 20 (solar cell 10) can be thinned while suppressing a decrease in photoelectric conversion efficiency. Furthermore, by thinning the cell component 20, the cell component 20 can be made transparent. The solar cell 10 can be used by being attached to a transparent member such as a window.

[0066] As described above, according to this embodiment, the solar cell 10 includes an optical member 30 having a first surface 31 and a second surface 32 located opposite the first surface 31, and a cell component 20 provided on the second surface 32 side of the optical member 30. The second surface 32 of the optical member 30 also has a plurality of protrusions 37 formed thereon. Each of the protrusions 37 extends along a first direction d1 and is arranged along a second direction d2 perpendicular to the first direction d1. The thickness T of the cell component 20 is smaller than the height H of the protrusions 37, and the cell component 20 is embedded between the protrusions 37. This facilitates total reflection of light L incident on the incident surface 11 of the solar cell 10 by the outer surface 20b of the cell component 20. This increases the range of light within the cell component 20 (power generation layer 25). This prevents a decrease in the photoelectric conversion efficiency of the power generation layer 25, even when the cell component 20 (power generation layer 25) is thin. Therefore, the thickness of the cell component 20 (solar cell 10) can be reduced while suppressing a decrease in photoelectric conversion efficiency.

[0067] Furthermore, according to the present embodiment, the cell component 20 contains a perovskite compound. When the cell component 20 contains a perovskite compound, it is common for the cell component 20 to contain lead to increase photoelectric conversion efficiency. However, to reduce the environmental impact of disposal of the solar cell 10, it may be necessary to reduce the amount of lead contained in the solar cell 10. Meanwhile, if, for example, lead is replaced with tin to reduce the lead content in the cell component 20, the photoelectric conversion efficiency of the cell component 20 may decrease. According to the present embodiment, the photoelectric conversion efficiency can be improved as described above, and therefore, even if the cell component 20 is thinned, a decrease in the photoelectric conversion efficiency of the cell component 20 can be suppressed. Therefore, even if the cell component 20 (power generation layer 25) contains a perovskite compound and lead, the amount of lead contained in the cell component 20 can be reduced by thinning the power generation layer 25. Therefore, the amount of lead contained in the cell component 20 can be reduced while maintaining high photoelectric conversion efficiency. As a result, the burden on the environment when the solar cell 10 is disposed of can be reduced.

[0068] In the above-described embodiment, an example has been described in which the cell component 20 is disposed on the substrate 3. In this case, as shown in Fig. 6, the solar cell 10 may further include a diffuse reflection sheet 40 provided on the side of the cell component 20 opposite to the optical member 30 side.

[0069] The diffuse reflective sheet 40 serves to reflect incident light while diffusing it. The diffuse reflective sheet 40 covers the entire surface of the cell component 20 in the third direction d3. In the illustrated example, the diffuse reflective sheet 40 is in contact with only a portion of the cell component 20. However, this is not limiting, and the diffuse reflective sheet 40 may be in contact with the entire surface of the cell component 20. In other words, the diffuse reflective sheet 40 may extend along the cell component 20 so as to follow the shape of the cell component 20.

[0070] The diffuse reflective sheet 40 may include fine particles having a refractive index different from that of the cell constituent portion 20. In this case, the diffuse reflective sheet 40 diffusely reflects light using the fine particles. Alternatively, the diffuse reflective sheet 40 may include a fine uneven structure. In this case, the diffuse reflective sheet 40 diffusely reflects light due to the difference in refractive index between the diffuse reflective sheet 40 and the cell constituent portion 20.

[0071] As in this modification, by diffusing and reflecting light using the diffuse reflection sheet 40, the range of light within the cell component 20 (power generation layer 25) can be increased, thereby further improving the photoelectric conversion efficiency in the power generation layer 25.

[0072] In the above-described embodiment, an example has been described in which the optical member 30 has the main body portion 33 and a plurality of convex portions 37 located closer to the second surface 32 than the main body portion 33. In this case, as shown in Figures 7 to 9, the optical member 30 may further have a plurality of prism portions 35 located closer to the first surface 31 than the main body portion 33.

[0073] 7 to 9, the optical member 30 has a main body 33, a plurality of prism portions 35 located closer to the first surface 31 than the main body 33, and a plurality of convex portions 37 located closer to the second surface 32 than the main body 33. In this modification, the main body 33 of the optical member 30 supports the prism portions 35 and the convex portions 37. The plurality of prism portions 35 are formed on the first surface 31.

[0074] The prism portion 35 is configured to make it easier for light incident on the solar cell 10 from diagonally above in the vertical direction to enter the optical member 30. The prism portion 35 is also configured to change the traveling direction of the light by refracting the light at the interface between the optical member 30 and the outside. The traveling direction of the light incident on the incident surface 11 of the solar cell 10 is changed by the prism portion 35 so that the angle of incidence on the power generation layer 25 becomes larger.

[0075] 8 and 9, the prism portions 35 are arranged along a first direction d1. Each prism portion 35 extends in a columnar shape along a second direction d2 that is non-parallel to the arrangement direction. Note that, although six prism portions 35 are arranged in the example shown in FIGS. 8 and 9, the number of prism portions 35 is not limited to this.

[0076] 9, the cross-sectional shape of the prism portion 35 is triangular in a cross section perpendicular to the second direction d2. The cross-sectional shape of the prism portion 35 may be any shape that appropriately changes the traveling direction of the transmitted light. The cross-sectional shape of the prism portion 35 may be determined based on the difference between the refractive index of the prism portion 35 and the refractive index outside the optical member 30. The refractive index of the prism portion 35 may be 1.45 or more, or 1.95 or less.

[0077] Each prism portion 35 includes a first inclined surface 35a facing one side of the first direction d1 in a cross section perpendicular to the second direction d2, and a second inclined surface 35b facing the other side of the first direction d1 in a cross section perpendicular to the second direction d2. The first inclined surface 35a faces one side of the first direction d1 (the right side in FIG. 9) in a cross section perpendicular to the second direction d2. The second inclined surface 35b faces the other side of the first direction d1 (the left side in FIG. 9) in a cross section perpendicular to the second direction d2.

[0078] The first inclined surface 35a is larger than the second inclined surface 35b. In this case, in a cross section perpendicular to the second direction d2, the length La of the first inclined surface 35a is longer than the length Lb of the second inclined surface 35b. As a result, by installing the solar power generation system 1 so that the first inclined surface 35a faces vertically upward, light incident on the solar cell 10 from diagonally above in the vertical direction is more likely to enter the optical member 30.

[0079] In such an optical member 30, the refractive index of the main body 33 and the refractive index of the prism portion 35 may be the same to avoid the formation of a reflective interface between the main body 33 and the prism portion 35. In this modification, the main body 33, the prism portion 35, and the convex portion 37 may be made of the same material. Alternatively, the main body 33, the prism portion 35, and the convex portion 37 may be integrally formed.

[0080] According to this modification, a plurality of prism portions 35 are formed on the first surface 31. This makes it possible to easily change the traveling direction of light so that the angle of incidence on the power generation layer 25 increases, thereby improving the photoelectric conversion efficiency.

[0081] Furthermore, according to this modification, each prism portion 35 includes a first inclined surface 35a facing one side of the first direction d1 in a cross section perpendicular to the second direction d2, and a second inclined surface 35b facing the other side of the first direction d1 in a cross section perpendicular to the second direction d2. Furthermore, the first inclined surface 35a is larger than the second inclined surface 35b in a cross section perpendicular to the second direction d2. Thus, by installing the solar power generation system 1 so that the first inclined surface 35a faces vertically upward, light incident on the solar cell 10 from diagonally above in the vertical direction is more likely to enter the optical member 30. This further improves the photoelectric conversion efficiency.

[0082] The components disclosed in the above-described embodiment and each modification may be combined as needed, or some components may be deleted from all the components shown in the above-described embodiment and each modification. [Explanation of symbols]

[0083] 1. Solar power generation system 3. Circuit Board 5 circuits 6 First connection part 7 Second connection part 10. Solar Cells 11 Entrance plane 20 Cell component 21 1st electrode layer 22 Second electrode layer 23 First carrier transport layer 24 Second carrier transport layer 25 Power Generation Layer 30 Optical Components 31 Page 1 32 2nd page 33 Main body 35 Prism section 35a 1st slope 35b 2nd slope 37 Convex part

Claims

1. an optical member having a first surface and a second surface located opposite the first surface; a cell component provided on the second surface side of the optical member, a plurality of convex portions are formed on the second surface of the optical member; Each of the protrusions extends along a first direction and is arranged along a second direction perpendicular to the first direction, the thickness of the cell constituent portion is smaller than the height of the protrusion, The solar cell, wherein the cell component is embedded between the protrusions.

2. The solar cell according to claim 1 , wherein the convex portion forms a lenticular lens.

3. The solar cell according to claim 1 , wherein a plurality of prism portions are formed on the first surface.

4. each of the prism portions includes, in a cross section perpendicular to the second direction, a first inclined surface facing one side of the first direction, and a second inclined surface facing the other side of the first direction, in a cross section perpendicular to the second direction; The solar cell according to claim 3 , wherein the first inclined surface is larger than the second inclined surface.

5. The solar cell according to claim 1 , wherein the cell components include a perovskite compound.

6. The solar cell according to claim 1 , further comprising a diffuse reflection sheet provided on the opposite side of the cell component from the optical member side.

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