WO2021181611A1

WO2021181611A1 - Solar cell module

Info

Publication number: WO2021181611A1
Application number: PCT/JP2020/010851
Authority: WO
Inventors: 染井秀徳; 福島岳行
Original assignee: 太陽誘電株式会社
Priority date: 2020-03-12
Filing date: 2020-03-12
Publication date: 2021-09-16
Also published as: JPWO2021181611A1

Abstract

This solar cell module is characterized by including: a transparent substrate provided with a first side surface, a second side surface, and a main surface; a power generation layer provided on the main surface of the transparent substrate; a sealing part provided so as to cover at least the first side surface, the second side surface, and a side surface of the power generation layer, wherein the transparent substrate is provided in plurality, and the plurality of transparent substrates are arranged so that the first side surface and the second side surface face each other.　

Description

Solar cell module

The present invention relates to a solar cell module.

With the growing interest in renewable energy, solar cells such as crystalline silicon solar cells and dye-sensitized solar cells are becoming widespread. These solar cells can obtain a large amount of electric power by increasing the power generation area. Therefore, a structure has been proposed in which a plurality of power generation layers are arranged side by side on the surface of one glass substrate, and these power generation layers generate power with light transmitted through the glass substrate (Patent Document 1).

However, in this structure, since a gap is formed between the adjacent power generation layers, the light that passes through the gap among the light irradiated to the glass substrate is not irradiated to the power generation layer, and the power generation efficiency is lowered. ..

International Publication No. 2017/022817

The present invention has been made in view of the above problems, and an object of the present invention is to improve power generation efficiency.

The solar cell module according to the present invention includes a transparent substrate having a first side surface, a second side surface, and a main surface, a power generation layer provided on the main surface of the transparent substrate, and at least the first side surface. A second side surface and a sealing portion provided so as to cover the side surface of the power generation layer are provided, and a plurality of the transparent substrates are provided, and the plurality of transparent substrates are the first side surface and the said. It is characterized in that it is arranged so as to face the second side surface.

In the solar cell module, a light reflecting portion having a refractive index different from that of the transparent substrate may be provided between the first side surface and the second side surface.

In the solar cell module, the light reflecting portion may contain a resin.

In the solar cell module, the resin may be any of acrylic resin, polycarbonate, epoxy resin, silicon resin, fluororesin, and engineering plastic.

In the solar cell module, a silane coupling layer may be provided on the first side surface, and the light reflecting portion may be provided on the silane coupling layer.

In the solar cell module, the light reflecting portion may include a light reflecting filler.

In the solar cell module, a reflective layer may be provided on the first side surface.

In the solar cell module, the reflective layer may be a metal oxide layer.

In the solar cell module, the sealing portion may contain a resin.

In the solar cell module, the power generation layer may be a layer of a plurality of semiconductor particles having a dye adsorbed on the surface.

According to the present invention, power generation efficiency can be improved.

It is sectional drawing of the solar cell used for examination. It is sectional drawing of the solar cell module which can obtain the higher voltage than the example of FIG. (A) and (b) are sectional views for explaining a problem. (A) and (b) are perspective views (No. 1) during the manufacturing of the solar cell according to the first embodiment. (A) and (b) are perspective views (No. 2) during the manufacturing of the solar cell according to the first embodiment. (A) and (b) are perspective views (No. 3) during the manufacturing of the solar cell according to the first embodiment. (A) and (b) are perspective views (No. 4) during the manufacturing of the solar cell according to the first embodiment. It is an enlarged sectional view of the edge part of the solar cell which concerns on 1st Embodiment. It is a top view of the solar cell module which concerns on 1st Embodiment. It is sectional drawing of the solar cell module which concerns on 1st Embodiment. (A), (b), and (c) are plan views showing an example of the arrangement of solar cells according to the first embodiment. It is an enlarged sectional view of the solar cell module which concerns on 1st Embodiment. It is an enlarged sectional view of the solar cell module which concerns on 2nd Embodiment. It is an enlarged sectional view of the solar cell module which concerns on 4th Embodiment. It is an enlarged sectional view of the solar cell module which concerns on other embodiments. It is an enlarged sectional view of the solar cell module which concerns on still another example of another embodiment.

Prior to the description of the present embodiment, the matters examined by the inventor of the present application will be described.
FIG. 1 is a cross-sectional view of the solar cell used in the study. The solar cell 1 is a dye-sensitized solar cell in which a transparent electrode layer 3, a reverse electron transfer prevention layer 4, a power generation layer 5, a solid electrolyte layer 6, and a counter electrode layer 7 are arranged in this order on a transparent substrate 2. It is formed.

Of these, the transparent substrate 2 is a glass substrate, on which an ITO (Indium Tin Oxide) layer is formed as a transparent electrode layer 3. Further, the reverse electron transfer prevention layer 4 is, for example, a titanium oxide layer made from a titanium alkoxide precursor. Further, the power generation layer 5 is a layer in which a dye is adsorbed on a plurality of titanium oxide fine particles. Examples of the dye include CYC-B11.

Further, the solid electrolyte layer 6 is a layer containing, for example, iodine and 1,3-dimethylimidazolium iodide (DMII), and a platinum layer, for example, is provided as a counter electrode layer 7 on the layer. Further, a resin sealing portion 8 for preventing the power generation layer 5 and the solid electrolyte layer 6 from being exposed to the atmosphere is provided on the side surface of the solar cell 1.

According to such a solar cell 1, the region where the transparent electrode layer 3, the reverse electron transfer prevention layer 4, the power generation layer 5, the solid electrolyte layer 6, and the counter electrode layer 7 overlap each other is the light transmitted through the transparent substrate 2. It becomes the cell area Rc that generates electricity in.

However, since this solar cell 1 has only one cell region Rc, a high voltage cannot be obtained. Although it depends on the type of dye-sensitized solar cell, the generated voltage of the solar cell 1 is only about 0.5 V in this example.

FIG. 2 is a cross-sectional view of the solar cell module 11 capable of obtaining a higher voltage than the example of FIG. In FIG. 2, the same elements as described in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted below.

As shown in FIG. 2, in the solar cell module 11, a plurality of cell regions Rc are formed by separating each layer 3 to 7 on the transparent substrate 2 into a plurality of layers. Further, a sealing portion 8 is provided between the cell regions Rc, and the sealing portion 8 prevents the power generation layers 5 of the cell regions Rc from being connected to each other.

According to this, it is possible to obtain a higher voltage than in FIG. 1 by connecting the batteries in the cell region Rc in series by wiring (not shown).

However, as a result of the examination by the inventor of the present application, it became clear that the solar cell module 11 has the following problems.

3 (a) and 3 (b) are cross-sectional views for explaining the problem. As shown in FIG. 3A, in the solar cell module 11, since the power generation layers 5 are separated into a plurality of layers, the light L passes through the gaps between the power generation layers 5. Therefore, the light L cannot be fully utilized effectively, and the power generation efficiency of the solar cell module 11 is lowered.

Further, as shown in FIG. 3B, in this example, since the transparent substrate 2 is provided large so as to cover each of the plurality of power generation layers 5, the transparent substrate 2 is cracked during the manufacturing of the solar cell module 11. 2x may occur.

(First Embodiment)
In the present embodiment, a dye-sensitized solar cell is manufactured as a solar cell as follows. 4 (a) to 7 (b) are perspective views of the solar cell according to the present embodiment during manufacturing.

First, as shown in FIG. 4A, a transparent substrate 20 having a first main surface 20a and a second main surface 20b facing each other is prepared. Of these surfaces, the first main surface 20a is an incident surface on which light is incident under actual use. On the other hand, on the second main surface 20b, an ITO layer is formed in advance as a transparent electrode layer 21 to a thickness of about 0.1 μm to 0.5 μm. Instead of the ITO layer, any one of the FTO (Fluorine doped Tin Oxide) layer, the zinc oxide layer, the laminated film of the indium-tin composite oxide layer and the silver layer, and the tin oxide layer doped with antimony is transparent. It may be formed as the electrode layer 21.

Further, the transparent substrate 20 is a glass substrate having a substantially square shape in a plan view, and the lengths Ax and Ay of one side thereof are 5 mm to 40 mm, for example, 15 mm. The thickness Az of the transparent substrate 20 is 0.1 mm to 3 mm, for example, 1.1 mm. A transparent plastic plate may be used as the transparent substrate 20 instead of the glass substrate.

Next, as shown in FIG. 4 (b), an alcohol solution prepared from titanium alkoxide is applied onto the transparent electrode layer 21 in the cell region Rc, and then the alcohol solution is heated and dried to cause reverse electrons. The movement prevention layer 22 is formed to have a thickness of about 5 nm to 0.1 μm. The drying temperature in this step is not particularly limited, and drying may be performed at a temperature of 450 ° C. to 650 ° C., for example, about 550 ° C.

Further, in the present embodiment, the right-angled triangular region at the corner portion 20h of the rectangular transparent substrate 20 is referred to as the first electrode region R1, and the pentagonal region excluding the corner portion 20h is referred to as the cell region Rc.

Of each side of the first electrode region R1 having a right angle triangle, the length Cx of one side sandwiching the right angle is 0.5 mm to 5 mm, for example, 3 mm, and the length Cy of the other side is 0.5 mm to. It is 5 mm, for example 3 mm. As a result, the area of the cell region Rc excluding the first electrode region R1 on the second main surface 20b of the transparent substrate 20 becomes ^{about 2.21 cm 2.}

The reverse electron transfer prevention layer 22 is formed only in the cell region Rc, and the transparent electrode layer 21 is exposed in the first electrode region R1.

Next, as shown in FIG. 5A, a titanium paste containing titanium oxide particles having a particle size of 5 nm to 50 nm, for example, 40 nm is placed on the reverse electron transfer prevention layer 22 by a screen printing method to a thickness of about 1 μm to 10 μm. Then, for example, it is applied to 5 μm and heated to remove organic components to form a power generation layer 25. The heating temperature of the slurry is 450 ° C. to 650 ° C., for example, 550 ° C., and the drying time is 10 minutes to 120 minutes, for example, about 30 minutes. The slurry is not particularly limited, but in this example, PST-30NRD, which is a titanium oxide paste manufactured by JGC Catalysts and Chemicals, is used as the slurry.

Further, the semiconductor particles constituting the power generation layer 25 are not limited to titanium oxide particles, and Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn. , Zr, Sr, Ga, Si, Cr, and Nb oxide particles may form the power generation layer 25. Further, the power generation layer 25 may be formed of particles of perovskite-type oxide such as _{SrTiO 3} and CaTiO _3.

The power generation layer 25 is formed only in the cell region Rc, the power generation layer 25 is not formed in the first electrode region R1, and the transparent electrode layer 21 of the first electrode region R1 is exposed. In this case, the area on which the titanium paste is printed is 2.21 cm ² .

After that, the transparent substrate 20 is immersed in an organic solution containing a dye, and the dye is adsorbed on the surface of the semiconductor particles constituting the power generation layer 25. As the organic solution, an organic solution prepared by adding CYC-B11 (K) as a dye to an organic solvent obtained by mixing acetonitrile and t-butanol in a volume ratio of 1: 1 is used. The concentration of the dye in the organic solution is 0.1 mM to 1 mM, for example, 0.2 mM. Then, the dye is adsorbed on the power generation layer 25 by allowing the transparent substrate 20 to stand in the organic solution for 1 to 12 hours, for example, 4 hours while keeping the organic solution at 0 ° C. to 80 ° C., for example, 50 ° C. Just let me do it.

Further, the dye is not limited to the above, and the metal complex dye or the organic dye may be adsorbed on the power generation layer 25. Among these, examples of the metal complex dye include transition metal complexes such as ruthenium-cis-diaqua-bipyridyl complex, ruthenium-tris complex, ruthenium-bis complex, osmium-tris complex, and osmium-bis complex. Zinc-tetra (4-carboxyphenyl) porphyrin and iron-hexacianide complex are also examples of metal complex dyes.

Examples of organic dyes include 9-phenylxanthene dyes, coumarin dyes, acridine dyes, triphenylmethane dyes, tetraphenylmethane dyes, quinone dyes, azo dyes, indigo dyes, and cyanine dyes. There are pigments, merocyanine pigments, xanthene pigments, carbazole compound pigments and the like.

Next, the process shown in FIG. 5 (b) will be described. First, as the solid electrolyte precursor 26, iodine, 1,3-dimethylimidazolium iodide (DMII), acetonitrile, and polyethylene oxide having a molecular weight of 1 million are mixed so as to be uniform. Next, the solid electrolyte precursor 26 is dropped onto the power generation layer 25 by 0.1 μL to 50 μL, for example, 20 μL, and the power generation layer 25 is impregnated with the solid electrolyte precursor 26. Then, the power generation layer 25 is heated to 50 ° C. to 150 ° C., for example, 100 ° C., and this state is maintained for 1 minute to 60 minutes, for example, 5 minutes to volatilize the excess acetonitrile contained in the solid electrolyte precursor 26. The solid electrolyte precursor 26 on the power generation layer 25 is designated as the solid electrolyte layer 27. After that, the power generation layer 25 is returned to room temperature.

The electrolyte contained in the solid electrolyte precursor 26 is not limited to DMII. For example, iodine salts such as pyridinium salt, imidazolium salt, and triazolium salt, which are in a solid state near room temperature or in a molten state, can be used as an ionic liquid. Examples of such a room temperature molten salt include 1-methyl-3-propylimidazolium iodide, 1-butyl-3-methylimidazolium iodide (BMII), 1-ethyl-pyridinium iodide and the like 4 There are quaternary ammonium salt compounds and the like.

Further, the material of the solid electrolyte layer 27 is not limited to the above, and an organic semiconductor material such as a molten salt containing an oxidation-reduction pair, an oxadiazole compound, and a pyrazoline compound may be used as the material of the solid electrolyte layer 27. .. Further, the solid electrolyte layer 27 may be formed of a metal halide material such as copper iodide or copper bromide.

Next, as shown in FIG. 6A, the counter electrode layer 33 is arranged above the solid electrolyte layer 27. The outer shape of the counter electrode layer 33 has the same pentagonal shape as the cell region Rc by cutting off one corner of a square having a side length of about 15 mm.

Further, the counter electrode layer 33 is formed by forming a catalyst layer 32 on a metal foil 31 having a thickness of 5 μm to 200 μm, for example, 100 μm, to a thickness of about 0.01 μm to 0.1 μm, for example, 0.05 μm. The metal foil 31 is, for example, a titanium foil, and the catalyst layer 32 is, for example, a platinum layer.

As the material of the catalyst layer 32, in addition to the above platinum, there are also metals having a catalytic function such as palladium, rhodium, and indium. Further, the catalyst layer 32 may be formed of graphite. Further, the catalyst layer 32 may be formed of carbon supporting platinum, an indium-tin composite oxide, antimony-doped tin oxide, and fluorine-doped tin oxide. Other materials include organic semiconductors such as poly (3,4-ethylenedioxythiophene) (PEDOT) and polythiophene.

Next, as shown in FIG. 6B, the counter electrode layer 33 is brought into close contact with the solid electrolyte layer 27 while removing air bubbles from between the solid electrolyte layer 27 and the counter electrode layer 33. By performing this step in a reduced pressure atmosphere or in a vacuum, air bubbles are less likely to remain between the solid electrolyte layer 27 and the counter electrode layer 33.

Further, in the cell region Rc, the transparent electrode layer 21, the power generation layer 25, the solid electrolyte layer 27, and the counter electrode layer 33 each overlap each other in a plan view, and are generated in the power generation layer 25 in the cell region Rc by the incident of light. Electricity will be generated.

Subsequently, as shown in FIG. 7A, a liquid obtained by diluting the silane coupling material with alcohol is applied onto each side surface of the transparent substrate 20 and each of the counter electrode layers 33 excluding the second electrode region R2. By applying and drying it, a silane coupling layer having a thickness of 0.1 μm to 10 μm is formed as the adhesion layer 40. As the silane coupling material, for example, there is KR-516 manufactured by Shin-Etsu Chemical Co., Ltd.

The close contact layer 40 is not formed on the counter electrode layer 33 in the second electrode region R2, and the counter electrode layer 33 is exposed in the second electrode region R2.

Next, as shown in FIG. 7B, an ultraviolet curable resin is applied onto the adhesion layer 40 and cured with ultraviolet rays to form a sealing portion 41 having a thickness of about 10 μm to 500 μm. As the ultraviolet curable resin, ThreeBond 3035B manufactured by ThreeBond Co., Ltd. is used here.

If the UV curable resin is applied and left as it is, the UV curable resin is immersed in the solid electrolyte layer 27, and the surface of the power generation layer 25 is covered with the UV curable resin. In order to prevent this, it is preferable to cure the ultraviolet curable resin within about 10 minutes after applying the ultraviolet curable resin.

As described above, the basic structure of the solar cell 50 according to the present embodiment is completed.
FIG. 8 is an enlarged cross-sectional view of the edge of the solar cell 50. As shown in FIG. 8, the above-mentioned adhesion layer 40 is formed on the side surface 20s of the transparent substrate 20, and the sealing portion 41 is formed on the adhesion layer 40. The adhesion layer 40 enhances the adhesion between the transparent substrate 20 and the sealing portion 41, and can prevent the sealing portion 41 from peeling off from the side surface 20s. The sealing portion 41 is provided so as to cover at least the side surface 20a of the transparent substrate 20 and the side surface of the power generation layer 25.

Further, the adhesion layer 40 is also formed on the side surface and the back surface of the counter electrode layer 33, and the sealing portion 41 is also formed on the adhesion layer 40. The adhesion layer 40 enhances the adhesion between the counter electrode layer 33 and the sealing portion 41, and can prevent the sealing portion 41 from peeling off from the counter electrode layer 33. If the adhesion between the side surface 20s and the sealing portion 41 and the adhesion between the counter electrode layer 33 and the sealing portion 41 are not a problem, the adhesion layer 40 may be omitted.

Next, a solar cell module using the solar cell 50 will be described.
FIG. 9 is a plan view of the solar cell module according to the present embodiment. As shown in FIG. 9, in the present embodiment, each of the eight solar cells 50 as the solar cell module 52 is arranged on the wiring board 51 with the transparent substrate 20 facing up. Further, a silver paste (not shown) is provided between each of the solar cells 50 and the wiring substrate 51, and the silver paste is cured by heating to cure the silver paste with the electrode regions R1 and R2 of the solar cell 50 and the wiring substrate. 51 is electrically connected. The silver paste is not particularly limited, but for example, DD-1630L-885 manufactured by Kyoto Elex Co., Ltd. can be used as the silver paste.

Further, in this example, by connecting each solar cell 50 in series with the wiring of the wiring board 51, a voltage eight times the voltage of one solar cell 50 is output from the solar cell module 52.

The wiring board 51 is provided with a secondary battery 53, a wireless circuit 54, and a sensor 55. Of these, the secondary battery 53 is, for example, a lithium ion battery or a lithium ion capacitor, and is stored by the electric power generated by the solar cell module 52. Further, the wireless circuit 54 and the sensor 55 are driven by the electric power of the secondary battery 53. For example, the sensor 55 is a temperature sensor or a humidity sensor, and transmits sensor information including the measured temperature and humidity to the wireless circuit 54. The wireless circuit 54 is a circuit that wirelessly transmits sensor information by, for example, BLE (Bluetooth (registered trademark) Low Energy).

FIG. 10 is a cross-sectional view of the solar cell module 52. As shown in FIG. 10, in the present embodiment, the transparent substrate 20 is provided for each solar cell 50, and one transparent substrate common to the plurality of solar cells 50 is not used. Therefore, the transparent substrate 20 is less likely to crack, and the durability of the solar cell module 52 is improved.

The arrangement of each solar cell 50 is not particularly limited. 11 (a) to 11 (c) are plan views showing an example of the arrangement of the solar cells 50.

As shown in FIGS. 11A to 11C, each of the solar cells 50 can be arranged on the wiring board 51 in any shape that shares one side in a plan view. In the conventional solar cell module, it is necessary to determine the shape of the wiring board 51 according to the shape of the cell, whereas in the present embodiment, the shape of the cell can be determined according to the shape of the wiring board 51, so that the solar cell The degree of freedom of arrangement of 50 is improved.

FIG. 12 is an enlarged cross-sectional view of the solar cell module 52 according to the present embodiment. As shown in FIG. 12, in the present embodiment, the solar cells 50 are arranged so that the side surfaces 20s of the adjacent transparent substrates 20 face each other.

When light L is obliquely incident on the side surface 20s of the transparent substrate 20, reflection, refraction, and scattering of light L occur based on the difference in refractive index between the transparent substrate 20 and the sealing portion 41. For example, when the light L is reflected on the side surface 20s of the transparent substrate 20, the light L is incident on the power generation layer 25, so that the amount of light incident on the power generation layer 25 is increased and the power generation efficiency in the solar cell module 52 is improved.

Further, when the light L is refracted on the side surface 20s of the transparent substrate 20, the refracted light L is incident on the power generation layer 25 of the adjacent solar cell 50, which also increases the amount of light incident on the power generation layer 25 and the solar cell module 52. Power generation efficiency is improved. Further, when the light L is scattered on the side surface 20s of the transparent substrate 20, the scattered light L is incident on each power generation layer 25 of the two adjacent solar cells 50, so that the light L is incident on each power generation layer 25. The amount of light increases and the power generation efficiency of the solar cell module 52 improves.

Moreover, when the sealing portion 41 is transparent, the light refracted or scattered on the side surface 20s of the transparent substrate 20 passes through the sealing portion 41, so that the amount of light incident on the power generation layer 25 of the adjacent solar cell 50 increases. , The power generation efficiency in the solar cell module 52 is improved.

In particular, the power generation layer 25 of the dye-sensitized solar cell has a thickness of about 1 μm to 10 μm, which is thicker than the thickness of the silicon layer of the silicon solar cell (100 nm). Therefore, the volume of the power generation layer 25 becomes large, and the light L is easily affected by reflection, refraction, and scattering. In particular, the area of the side surface 25s of the power generation layer 25 is larger than that of the silicon solar cell, and the light reflected by the side surface 20s is incident on the wide side surface 25s to further improve the power generation efficiency of the power generation layer 25.

The distance t between the adjacent side surfaces 20s is not particularly limited, but in the present embodiment, the distance t between the side surfaces 20s is 2 mm or less. As a result, it is possible to suppress the area of the power generation layer 25 per one solar cell module 52 from becoming small, and it is possible to prevent the power generation efficiency of the solar cell module 52 from decreasing.

(Second Embodiment)
FIG. 13 is an enlarged cross-sectional view of the solar cell module 52 according to the present embodiment. In FIG. 13, the same elements as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and the description thereof will be omitted below.

As shown in FIG. 13, in the present embodiment, the gap between the adjacent solar cells 50 is filled with a silicone resin as a light reflecting portion 61. As the silicone resin, for example, there is a silicone sealant (clear) manufactured by Cainz Corporation. The refractive index of this silicone resin is 1.41.

Since the refractive index of the glass or the sealing resin 41, which is the material of the transparent substrate 20, is about 1.5, in the present embodiment, each of the transparent substrate 20 and the sealing resin 41 and the light reflecting portion 61 having a different refractive index are provided. It will be provided between the solar cells 50. Due to the difference in refractive index between the transparent substrate 20 and the light reflecting portion 61, the reflectance of the light L on the side surface 20s is increased in the present embodiment. As a result, more light reflected by the side surface 20s of the transparent substrate 20 is incident on the power generation layer 25, so that the intensity of the light incident on the power generation layer 25 is increased and the power generation efficiency in the solar cell module 52 is further improved.

Moreover, since the resin, which is the material of the light reflecting portion 61, has a smaller elastic modulus than the glass, which is the material of the transparent substrate 20, it functions as a stress relaxation layer that relieves the stress applied to the transparent substrate 20. Therefore, it is possible to prevent the transparent substrate 20 from cracking during manufacturing or use of the solar cell module 52, and it is possible to improve the durability of the solar cell module 52.

The material of the light reflecting portion 61 is not limited to the silicone resin. The light reflecting portion 61 may be formed of any of polycarbonate, epoxy resin, fluororesin, and engineering plastic.

(Third Embodiment)
In this embodiment, an acrylic resin is used as the material of the light reflecting portion 61 (see FIG. 13). As the acrylic resin, SS-101 Super Clear manufactured by Epoch Co., Ltd. was used. The refractive index of this acrylic resin is 1.51. Other than this, it is the same as that of the second embodiment.

(Fourth Embodiment)
FIG. 14 is an enlarged cross-sectional view of the solar cell module 52 according to the present embodiment. In FIG. 14, the same elements as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and the description thereof will be omitted below.

As shown in FIG. 14, in the present embodiment, a material in which the light reflecting filler 62 is mixed with the light reflecting portion 61 is used. Instead of titanium oxide, a metal or glass light-reflecting filler 62 may be used. Further, as the light reflecting portion 61, a POS seal (white), which is a silicone resin manufactured by Cemedine Co., Ltd., was used. The refractive index of this silicone resin is 1.41. Other than this, it is the same as that of the second embodiment.

By mixing the light reflecting filler 62 with the light reflecting unit 61 in this way, the light L that has entered the light reflecting unit 61 is reflected inside the light reflecting unit 61 and is incident on the power generation layer 25. Therefore, the light L can be efficiently guided to the power generation layer 25, and the power generation efficiency of the solar cell module 52 can be further improved.

Moreover, since the light scattered inside the light reflecting unit 61 is incident on the power generation layer 25 of the solar cell 50 adjacent to the light reflecting unit 61, the amount of light incident on the power generation layer 25 increases, and the solar cell The power generation efficiency in the module 52 is improved.

(Fifth Embodiment)
In this embodiment, silicone rubber is used as the material of the light reflecting portion 61 (see FIG. 13). As the silicone rubber, a one-component RTV rubber (clear) manufactured by Shin-Etsu Chemical Co., Ltd. was used. The refractive index of the silicone rubber is 1.41. Other than this, it is the same as that of the second embodiment.

Silicone rubber has a very small elastic modulus compared to other resins. Therefore, the light reflecting portion 61 is flexibly deformed with respect to the stress applied to the transparent substrate 20, and the light reflecting portion 61 can function as a stress relaxation layer for relaxing the stress.

(Other embodiments)
FIG. 15 is an enlarged cross-sectional view of the solar cell module 52 according to the present embodiment. In FIG. 15, the same elements as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and the description thereof will be omitted below.

As shown in FIG. 15, in the present embodiment, the reflective layer 59 is provided on the side surface 20s of the transparent substrate 20. The reflective layer 59 is a metal oxide layer such as titanium oxide having a thickness of about 0.1 μm. As a result, the reflectance on the side surface 20s is increased as compared with the case where the reflection layer 59 is not provided, so that the light L can be almost certainly reflected on the side surface 20s and led to the power generation layer 25, and the power generation efficiency of the solar cell module 52 can be increased. Can be further enhanced. Moreover, since the metal oxide layer does not have the luster of the metal layer, light can be scattered. As a result, the scattered light is incident on each power generation layer 25 of the plurality of solar cells 50 in a wide range, and the light can be effectively used in each solar cell 50.

FIG. 16 is an enlarged cross-sectional view of the solar cell module 52 according to still another example of the present embodiment.
Also in this example, as in the second embodiment, the gap between the adjacent solar cells 50 is filled with the resin as the light reflecting portion 61. As a result, the light reflecting portion 61 functions as a stress relaxation layer, so that the stress applied to the transparent substrate 20 can be relaxed by the light reflecting portion 61, and the transparent substrate 20 can be prevented from cracking due to the stress.

The inventor of the present application produced the solar cell module 52 according to the first to fifth embodiments described above, and investigated the amount of power generation of the solar cell module 52 by experiments. The experiment will be described below.
(First experimental example)
In this example, the solar cell 50 was manufactured according to the first embodiment. The lengths Ax and Ay of one side of the transparent substrate 20 were 15 mm, and the thickness Az was 1.1 mm. The thickness of the transparent electrode layer 21 was set to 0.3 μm. Then, an alcohol solution prepared from titanium alkoxide is applied onto the transparent electrode layer 21 in the cell region Rc, and then the alcohol solution is heated to 550 ° C. and dried to make the reverse electron transfer prevention layer 22 0.005 μm. It was formed to a thickness of ~ 0.01 μm.

Further, a titanium paste containing titanium oxide particles of 40 nm is applied on the reverse electron transfer prevention layer 22 to a thickness of 5 μm to 10 μm, and the power generation layer 25 is removed by heating it to 550 ° C. to remove organic components. Formed. Further, CYC-B11 (K) was added as a dye to an organic solvent in which acetonitrile and t-butanol were mixed at a volume ratio of 1: 1. Then, while keeping the organic solvent at 50 ° C., the transparent substrate 20 was immersed in the organic solution for 4 hours to adsorb the dye on the power generation layer 25. The concentration of the dye in the organic solvent was 0.2 mM.

Then, iodine, 1,3-dimethylimidazolium iodide (DMII), acetonitrile, and polyethylene oxide having a molecular weight of 1 million were mixed so as to be uniform to prepare a solid electrolyte precursor 26. Then, after dropping 20 μL of the solid electrolyte precursor 26 onto the power generation layer 25, the power generation layer 25 was heated to 100 ° C. The heating time was 100 ° C. and the heating time was 5 minutes. As a result, the excess acetonitrile contained in the solid electrolyte precursor 26 was volatilized, and the solid electrolyte layer 27 was obtained. After that, the power generation layer 25 was returned to room temperature.

Next, the counter electrode layer 33 formed by forming a platinum layer having a thickness of 0.05 μm on a titanium foil having a thickness of 100 μm was brought into close contact with the solid electrolyte layer 27. Then, a silane coupling layer having a thickness of 0.5 μm was formed as an adhesion layer 40 on each side surface of the transparent substrate 20 and each of the counter electrode layers 33 excluding the second electrode region R2. Further, the solar cell 50 was manufactured by forming a sealing portion 41 having a thickness of 150 μm on the adhesion layer 40. The solar cell module 52 was manufactured by connecting eight solar cells 50 in series.

The inventor of the present application conducted the following investigation in order to confirm the amount of power generated by the solar cell module 52. In the investigation, the solar cell module 52 was installed in a dark room, and the solar cell module 52 was irradiated with the light of a standard LED (Light Emitting Diode) light source in the dark room. As the standard LED light source, BLD-100 manufactured by Spectrometer Co., Ltd. was used. Further, in order to confirm the illuminance of light, a light receiving part of HD2102.1 manufactured by Delta Ohmsha was placed as a portable illuminance meter directly under the standard LED light source.

Under such conditions, when the solar cell module 52 in which eight solar cells 50 were connected in series was irradiated with 200 Lux of light, the amount of power generated by the solar cell module 52 was 53.7 μW. The amount of power generated for 1000 Lux of light was 268.2 μW.

(Second experimental example)
In this example, the solar cell module 52 was manufactured according to the second embodiment. As the silicone resin used as the material of the light reflecting portion 61, a silicone sealant (clear) manufactured by Cainz Corporation having a refractive index of 1.41 was used.

The inventor of the present application investigated the amount of power generated by the solar cell module 52 according to this example under the same conditions as in the first experimental example. As a result, the amount of power generated for 200 Lux of light was 54.0 μW. The amount of power generated for 1000 Lux of light was 270.2 μW.

(Third experimental example)
In this example, the solar cell module 52 was manufactured according to the third embodiment. As the acrylic resin used as the material of the light reflecting portion 61, SS-101 Super Clear manufactured by Epoch Co., Ltd. having a refractive index of 1.51 was used.

The inventor of the present application investigated the amount of power generated by the solar cell module 52 according to this example under the same conditions as in the first experimental example. As a result, the amount of power generated for 200 Lux of light was 54.1 μW. The amount of power generated for 1000 Lux of light was 272.9 μW.

(Fourth experimental example)
In this example, the solar cell module 52 was manufactured according to the fourth embodiment. Titanium oxide particles were used as the light-reflecting filler 62 to be mixed with the light-reflecting portion 61. Further, as the silicone resin which is the material of the light reflecting portion 61, a POS seal (white) of Cemedine Co., Ltd. having a refractive index of 1.41 was used.

The inventor of the present application investigated the amount of power generated by the solar cell module 52 according to this example under the same conditions as in the first experimental example. As a result, the amount of power generated for 200 Lux of light was 54.5 μW. The amount of power generated for 1000 Lux of light was 274.3 μW.

(Fifth experimental example)
In this example, the solar cell module 52 was manufactured according to the fifth embodiment. As the silicone rubber used as the material of the light reflecting portion 61, a one-component RTV rubber (clear) manufactured by Shin-Etsu Chemical Co., Ltd. having a refractive index of 1.41 was used.

The inventor of the present application investigated the amount of power generated by the solar cell module 52 according to this example under the same conditions as in the first experimental example. As a result, the amount of power generated for 200 Lux of light was 54.2 μW. The amount of power generated for 1000 Lux of light was 272.4 μW.

(Comparison example)
In this comparative example, the length Ax of the long side of the transparent substrate 20 (see FIG. 4A) is 60 mm, and the length Ay of the short side is 30 mm, so that the cell region Rc is larger than that of the first experimental example. Made a large solar cell 50. In this case, the power generation area in this comparative example is substantially equal to the power generation area of the solar cell module 52 in which eight solar cells 50 are connected in series as in the first experimental example. Then, the amount of power generated by the solar cell 50 alone according to this comparative example was measured. The measurement conditions are the same as in the first experimental example. As a result, the amount of power generated for 200 Lux of light was 48.4 μW, and the amount of power generated for 1000 Lux of light was 243.5 μW. These values are smaller than the values in each of the first to fifth experimental examples. From this, it was confirmed that it is effective to improve the power generation efficiency by making the side surfaces 20s of the plurality of transparent substrates 20 face each other as in the first to fifth embodiments.

Although each embodiment has been described in detail above, the present invention is not limited to the above. For example, in the above, the dye-sensitized solar cell is manufactured as the solar cell 50, but the silicon solar cell may be manufactured as the solar cell 50.

1,50

Solar cell

2,20

Transparent substrate

3,21

Transparent electrode layer

4,22 Reverse electron

movement prevention layer

5,25

Power generation layer

6,27

Solid electrolyte layer

7,33

Opposed electrode

8,41 Sealing part 11 Solar cell module 20s Side 31 Metal foil 32 Catalyst layer 40 Adhesive layer 51 Wiring board 52 Solar cell module 53 Secondary battery 54 Wireless circuit 55 Sensor 59 Reflection layer 61 Light reflection part 62 Light reflection filler

Claims

A transparent substrate with a first side surface, a second side surface, and a main surface,
A power generation layer provided on the main surface of the transparent substrate and
At least the first side surface, the second side surface, and the sealing portion provided so as to cover the side surface of the power generation layer.
Have,
A plurality of the transparent substrates are provided,
The plurality of transparent substrates are arranged so that the first side surface and the second side surface face each other.
A solar cell module characterized by that.
The solar cell module according to claim 1, wherein a light reflecting portion having a refractive index different from that of the transparent substrate is provided between the first side surface and the second side surface.
The solar cell module according to claim 2, wherein the light reflecting portion contains a resin.
The solar cell module according to claim 3, wherein the resin is any one of an acrylic resin, a polycarbonate, an epoxy resin, a silicon resin, a fluororesin, and an engineering plastic.
The solar cell module according to claim 3, wherein a silane coupling layer is provided on the first side surface, and the light reflecting portion is provided on the silane coupling layer.
The solar cell module according to any one of claims 2 to 5, wherein the light reflecting unit contains a light reflecting filler.
The solar cell module according to any one of claims 1 to 6, wherein a reflective layer is provided on the first side surface.
The solar cell module according to claim 7, wherein the reflective layer is a metal oxide layer.
The battery module according to any one of claims 1 to 8, wherein the sealing portion contains a resin.
The solar cell module according to any one of claims 1 to 9, wherein the power generation layer is a layer of a plurality of semiconductor particles in which a dye is adsorbed on the surface.