Solar Cell Module

Abstract

The present invention comprises: a solar battery string (2) that has a plurality of power generation cells (20); a translucent protection plate (3) that is laid over the light incidence side of the solar battery string (2); a sealing material (4) that is interposed between the solar battery string (2) and the protection plate (3); and a decorative layer (5) that is formed so as to be visible through the protection plate (3) from the light incidence side of the protection plate (3) and attenuates or blocks light in the thickness direction. The decorative layer (5) is formed between the protection plate (3) and the solar battery string (2) in the thickness direction.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Application No. 2021-185781, the entire disclosure of which is incorporated herein by reference. [Technical field]

[0002] The present invention relates to a solar cell module. [Background technology]

[0003] Conventionally, a solar cell module has been proposed in which the periphery of the power generating cell is painted for aesthetic purposes (Patent Document 1). This solar cell module includes a back sheet, an adhesive layer formed on the back sheet, and a wiring sheet (conductive sheet member) provided on the back sheet on which the adhesive layer is formed. The solar cell module also includes a plurality of solar cells (power generating cells) provided on the wiring sheet, a light receiving surface side sealing material provided in order on the solar cell, and a cover glass.

[0004] This solar cell module has multiple cell groups each made up of a row of solar cells. In addition, the solar cell module has areas other than the multiple cell groups painted black, improving the appearance and design (paragraph 0090). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-170815 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, in order to hide wiring materials and the like and obtain a high design, a black-painted portion may be provided on the light receiving surface side of such a solar cell module. In this configuration, direct sunlight may be incident obliquely with respect to the normal direction of the solar cell module depending on the installation angle, orientation, and time of day. In this case, the black-painted portion (coating) may cause some solar cells (power generating cells) to block sunlight. If the amount of light received by a solar cell that blocks sunlight by the coating decreases, the cell becomes a resistor within the module. This may cause the amount of power generation of cells other than the solar cell in the module to decrease, making it difficult to ensure the desired output. In this way, there is a risk that the power generation efficiency of the entire solar cell module, including solar cells that do not block sunlight, may decrease.

[0007] An object of the present invention is to provide a solar cell module capable of suppressing a decrease in output even when a decorative layer such as a coating film is formed so as to be visible from the surface of a protective plate (glass). [Means for solving the problem]

[0008] The solar cell module of the present invention comprises a solar cell string having a plurality of power generating cells that generate electricity by receiving light, a light-transmitting protective plate superimposed on the light incident side of the solar cell string, a sealing material interposed between the solar cell string and the protective plate, and a decorative layer that reduces light or blocks light in the thickness direction and is formed so as to be visible through the protective plate from the light incident side surface of the protective plate, the decorative layer being formed between the protective plate and the solar cell string in the thickness direction.

[0009] In the solar cell module, the decorative layer may be a coating film formed on the rear surface of the protective plate opposite to the light incident side.

[0010] In the solar cell module, the coating film may be formed so as not to contact an edge of the protective plate.

[0011] In addition, the solar cell module may have a frame portion that is exposed and arranged along the outer edge of the protective plate, and the frame portion may be arranged so as not to overlap the decorative layer when the protective plate is viewed in the thickness direction.

[0012] In addition, in the solar cell module, the multiple power generating cells are elongated and slender in shape, and the solar cell string is formed by connecting the multiple power generating cells in a shingled manner, and the decorative layer may be formed and arranged at each of positions corresponding to both ends in the connection direction of the solar cell string formed by the shingled connection.

[0013] In addition, in the solar cell module, the solar cell string may further have a dummy cell that is not electrically connected to any of the plurality of power generation cells and does not contribute to power generation of the solar cell string, and the dummy cell may be positioned closer to the decorative layer in a planar view than any of the plurality of power generation cells. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic plan view of a solar cell module according to this embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view taken along line II-II of FIG. [Diagram 3] FIG. 3 is a schematic cross-sectional view of a solar cell module according to a comparative example. [Figure 4] FIG. 4 is a schematic plan view of a solar cell module according to a modified example. [Diagram 5] FIG. 5 is a schematic cross-sectional view taken along the line VV in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

[0016] As shown in FIG. 1 and FIG. 2, the solar cell module 1 includes a solar cell string 2 and a translucent protective plate 3 superimposed on the light incident side of the solar cell string 2. The solar cell module 1 also includes a sealing material 4 interposed between the solar cell string 2 and the protective plate 3, and a decorative layer 5 formed so as to be visible through the protective plate 3 from the surface 30 on the light incident side of the protective plate 3, and performing light reduction or light blocking in the thickness direction. The solar cell module 1 also includes a frame 6 disposed on the outer edge of the protective plate 3, and in this embodiment, disposed exposed along the outer edge of the protective plate 3. The solar cell module 1 is plate-shaped, and is installed on the roof of a building such as a private house, for example, with the main surface (light receiving surface) facing upward (toward the sun). In the solar cell module 1, the decorative layer 5 is formed between the protective plate 3 and the solar cell string 2. In the solar cell module 1, the solar cell string 2 has a power generating cell 20 that generates power by receiving light.

[0017] On the other hand, in the solar cell module 11 according to the comparative example, as shown in FIG. 3, the decorative layer 5 is formed on the surface 30 of the protective plate 3. Therefore, the decorative layer 5 blocks sunlight from entering some of the power generating cells 20. Specifically, in this solar cell module 11, the decorative layer 5 blocks all or part of the sunlight from entering the power generating cells 20a and 20b that are close to the decorative layer 5 in a plan view. When the amount of light received by the power generating cells 20a and 20b that are blocked by the decorative layer 5 decreases, the power generating cells 20a and 20b become resistors in the solar cell module 11. As a result, the amount of power generated by the power generating cells 20c, 20d, and 20e other than the power generating cells 20a and 20b in the solar cell module 11 also decreases, resulting in a phenomenon in which the desired output cannot be secured. In this way, there is a risk that the power generation efficiency of the entire solar cell module 11 will decrease, including the power generating cells 20c, 20d, and 20e that are not blocked by sunlight due to the influence of the decorative layer 5.

[0018] In contrast, according to the solar cell module 1 of this embodiment, the decorative layer 5 is formed between the protective plate 3 and the solar cell string 2 in the thickness direction, not on the surface 30 of the protective plate 3. Therefore, compared to when the decorative layer 5 is formed on the surface 30 of the protective plate 3, the decorative layer 5 can be brought closer to the solar cell string 2 in the thickness direction of the solar cell module 1 (the vertical direction in FIG. 2). Therefore, by bringing the decorative layer 5 closer to the solar cell string 2, the area in the solar cell string 2 where sunlight is blocked or dimmed by the decorative layer 5 can be made smaller. Specifically, the power generating cell 20 where sunlight is blocked by the decorative layer 5 can be limited to only the power generating cell 20a. That is, the number of power generating cells 20 where sunlight is blocked by the decorative layer 5 can be reduced. Therefore, the power generating efficiency of the solar cell string 2 can be suppressed from decreasing. In this way, since the decorative layer 5 is formed between the protective plate 3 and the solar cell string 2, the power generating efficiency of the solar cell string 2 can be suppressed from decreasing, and therefore the output reduction of the solar cell module 1 can be suppressed.

[0019] In the solar cell string 2, each power generating cell 20 has an elongated shape, and the multiple power generating cells 20 are connected in a shingle connection. The shingle connection is a connection in which the elongated power generating cells 20 are sequentially arranged so that the long sides of the power generating cells 20 overlap, like roof shingles. In addition, a decorative layer 5 is formed and arranged at positions corresponding to both ends in the connection direction of the solar cell string 2 related to the shingle connection.

[0020] In this manner, in a solar cell string 2 in which a plurality of power generating cells 20 are connected in a shingled manner, each power generating cell 20 is smaller than in other connection methods, and output reduction due to the influence of sunlight shading or dimming caused by the decorative layer 5 is more likely to occur. Therefore, in a solar cell module 1 including such a solar cell string 2, it is possible to effectively counter output reduction caused by the decorative layer 5. Furthermore, output reduction of the solar cell module 1 can be suppressed regardless of whether sunlight shading or dimming occurs on either side of the connection direction of the shingled connection due to the decorative layer 5.

[0021] Furthermore, the solar cell string 2 has at least one power generating cell 20, and specifically, has a plurality of power generating cells 20. The size of each power generating cell 20 (in the solar cell string 2 connected in a single ring), is the same. Each power generating cell 20 has, for example, a rectangular plate shape.

[0022] The protective plate 3 is, for example, a glass plate. The thickness of the protective plate 3 is, for example, 2 mm or more and 8 mm or less. The sealing material 4 is adhered to the protective plate 3.

[0023] In the solar cell module 1 of the present embodiment, the protective plate 3 is provided only on the front surface 22 of the solar cell string 2. In this case, a resin sheet 7 is provided on the back surface 23 of the solar cell string 2. The protective plate 3 may be provided on both the front surface 22 and the back surface 23 of the solar cell string 2.

[0024] The sealing material 4 is, for example, layered on each of the front surface 22 and the back surface 23 of the solar cell string 2. The sealing material 4 is, for example, a resin layer. The sealing material 4 also covers the end faces (outer periphery) of the solar cell string 2. Specifically, the sealing material 4 continuously covers the front surface 22, the back surface 23, and the end faces of the solar cell string 2.

[0025] The decorative layer 5 is provided to improve the appearance of the solar cell module 1, for example, by hiding the electrical wiring around the solar cell string 2. The decorative layer 5 is, for example, a coating film formed on the back surface 31 of the protective plate 3, which is the side opposite to the light incident side. Therefore, the decorative layer 5 can effectively prevent output reduction in a solar cell module 1 in which a general method (painting) for improving aesthetics is used. In addition, since the coating film is formed on the back surface 31 of the protective plate 3, peeling of the coating film over time is less likely to occur compared to a configuration in which a coating film is formed on the front surface 30 of the protective plate 3.

[0026] In a solar cell module, if the adhesive strength of the end is insufficient, moisture and the like easily penetrates in the environment, which causes damage to long-term reliability. In contrast, in the solar cell module 1 of this embodiment, the coating film is formed so as not to contact the edge 32 of the protective plate 3. As a result, since the coating film does not exist on the edge 32 of the protective plate 3, the adhesive strength when adhering the protective plate 3 and the sealing material 4 is not reduced at the edge 32 of the protective plate 3. Therefore, even if a force is applied to the edge 32 of the protective plate 3 when assembling the solar cell module 1, for example, when attaching the frame 6, the protective plate 3 and the sealing material 4 are not easily peeled off. In addition, since the end of the solar cell module 1 is not painted, the color of the end and the other parts of the solar cell module 1 are different, and the frame 6 can be provided so as not to overlap the decorative layer 5 (coating film) when the protective plate 3 is viewed in the thickness direction. In other words, the frame 6 can be attached so as to cover the part (end) where the coating film is not formed (so as to cover the edge of the protective plate 3), and the unity of the entire module can be maintained by adjusting the color of the frame 6.

[0027] Specifically, the decorative layer 5 is a coating film having a thickness of 5 μm to 50 μm. This coating film is formed, for example, by ceramic printing. The decorative layer 5 is a coating film that blocks incident light or transmits (attenuates) a certain amount of the incident light. In the solar cell module 1 of this embodiment, the decorative layer 5 is a black coating film, but may be a coating film of another color.

[0028] The decorative layer 5 is, for example, a coating film in which a predetermined area is filled (solid coating). The decorative layer 5 may be a coating film in which a combination of a light-shielding area and a light-transmitting area is formed adjacent to each other on the surface of the protective plate 3, thereby reducing light in the thickness direction. Specifically, the decorative layer 5 may be a coating film in which a predetermined area is applied in a dot pattern or a mesh pattern. The decorative layer 5 may be a light-shielding member such as a film of black or other color other than a coating film. The decorative layer 5 may be a part of the sealing material 4 colored black or the like (such as a resin material mixed with a pigment), and the colored sealing material 4 may be disposed so as to be in contact with the back surface 31 of the protective plate 3.

[0029] The decorative layer 5 is disposed on the outer edge of the protective plate 3, and is a separate member from a frame 6 provided to shape and reinforce the solar cell module 1.

[0030] 4 and 5, the solar cell string 2 may have a power generating cell 20 that generates power by receiving light, and a dummy cell 21 that is not electrically connected to any of the power generating cells 20 and does not contribute to power generation by the solar cell string 2. In this solar cell string 2, the dummy cell 21 is disposed at a position closer to the decorative layer 5 than any of the power generating cells 20 in a plan view (see FIG. 4).

[0031] In the solar cell string 2, dummy cells 21 that do not contribute to power generation are arranged in a portion where sunlight is blocked or reduced by the decorative layer 5 (see FIG. 5). Therefore, the effect of blocking or reducing sunlight by the decorative layer 5 does not extend to the power generating cells 20, and a decrease in the power generation efficiency of the solar cell string 2 can be more effectively prevented.

[0032] In addition, in this solar cell string 2, the power generating cells 20 and the dummy cells 21 have at least the same shape in a plan view (see FIG. 4). In this embodiment, the power generating cells 20 and the dummy cells 21 have approximately the same thickness, and the color of the dummy cells 21 is also close to the color of the power generating cells 20 (see FIG. 5). This allows the power generating cells 20 and the dummy cells 21 to have the same appearance through the protective plate 3 in a plan view, so that the appearance of the solar cell module 1 is not marred even when the dummy cells 21 are arranged. Note that each solar cell string 2 may be composed of one power generating cell 20 and at least one dummy cell 21.

[0033] In the above solar cell module 1, sample A, sample B (see FIG. 2), and sample C (see FIG. 5) were prepared, and a simulation was performed to calculate the amount of power generation. In sample A, the decorative layer 5 is formed on the surface 30 of the protective plate 3. In sample B, the decorative layer 5 is formed between the protective plate 3 and the solar cell string 2, and the solar cell string 2 is composed of all the power generating cells 20. In sample C, the decorative layer 5 is formed between the protective plate 3 and the solar cell string 2, and the solar cell string 2 related to the shingling connection is composed of a dummy cell 21 provided on one side in the connection direction and a plurality of power generating cells 20. In these solar cell modules 1, the width of the power generating cell 20 is 24 mm, and the thickness of the protective plate 3 (glass plate) is 6 mm. In addition, the solar cell module 1 was installed at an angle of 90 degrees and faced south. Note that the 90 degree installation means that the solar cell module 1 is installed at an angle of 90 degrees with respect to the horizontal plane.

[0034] In this simulation, calculations were performed assuming that when direct light or quasi-direct light is blocked by the decorative layer 5, the direct light or quasi-direct light is attenuated by the proportion of light that falls on the dummy cell 21 or the power generating cell 20 located at the very end on one side (sun side) in the connection direction of the solar cell string 2. Note that the solar radiation amount used in the simulation was the average year value data for Fukuoka from the annual hourly solar radiation database (METPV-11).

[0035] As a result of this simulation, the annual power generation per 1 kW installation was 653 kWh for sample A (a sample in which the decorative layer 5 was formed on the surface 30 of the protective plate 3). The annual power generation was 755 kWh for sample B (a sample in which the decorative layer 5 was formed between the protective plate 3 and the solar cell string 2, and the solar cell string 2 was composed entirely of the power generating cells 20). The annual power generation was 766 kWh for sample C (a sample in which the decorative layer 5 was formed between the protective plate 3 and the solar cell string 2, and the solar cell string 2 relating to the single connection was composed of a dummy cell 21 provided on one side in the connection direction and a plurality of power generating cells 20). Thus, the result was obtained that the power generation increased by about 16% by forming the decorative layer 5 between the protective plate 3 and the solar cell string 2.

[0036] The solar cell module of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the scope of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, part of the configuration of one embodiment can be deleted.

[0037] The solar cell module 1 in the above embodiment is installed with the main surface (light receiving surface) facing upward, for example, but is not limited thereto. For example, it may be attached to a vertical surface such as an outer wall of a private house or a surface close to the vertical surface (for example, a surface inclined at 15° or less from the vertical surface). In this case, the solar cell module 1 may be provided with a mounting portion (bracket, etc.) for mounting to a vertical surface, etc. For example, the mounting portion is provided on a frame portion 6. In the solar cell module 1 provided with the mounting portion, if the power generating cells 20 and the dummy cells 21 have at least the same shape in a plan view, when the solar cell module 1 is installed on a vertical surface using the mounting portion, even if the solar cell string 2 located in an easily visible position is seen through the protective plate 3, there is no problem in terms of aesthetics.

[0038] In the solar cell string 2 of the above embodiment, the power generating cell 20 has an elongated shape, and the multiple power generating cells 20 are connected in a single ring, but this is not limited thereto. The shape of the power generating cell 20 may be a shape other than an elongated shape, such as a square plate shape, and the multiple power generating cells 20 may not be connected in a single ring, but may be connected by wiring material.

[0039] As described above, according to the present invention, it is possible to provide a solar cell module capable of suppressing a decrease in output even when a decorative layer such as a coating film is formed so as to be visible from the surface of the protective plate (glass).

[0040] (1) The solar cell module of the present invention comprises a solar cell string having a plurality of power generating cells that generate electricity by receiving light, a light-transmitting protective plate superimposed on the light incident side of the solar cell string, a sealing material interposed between the solar cell string and the protective plate, and a decorative layer that reduces light or blocks light in a thickness direction and is formed so as to be visible through the protective plate from the light incident side surface of the protective plate, wherein the decorative layer is formed between the protective plate and the solar cell string in the thickness direction.

[0041] According to this configuration, the decorative layer is formed between the protective plate and the solar cell string, not on the surface of the protective plate. Therefore, compared to when the decorative layer is formed on the surface of the protective plate, the decorative layer can be brought closer to the solar cell string in the module thickness direction, and the area in the solar cell string where sunlight is blocked or dimmed by the decorative layer can be made smaller accordingly. This makes it possible to suppress a decrease in the power generation efficiency of the solar cell string. In this way, by forming the decorative layer between the protective plate and the solar cell string, a decrease in the power generation efficiency of the solar cell string can be suppressed, and therefore a decrease in the output of the solar cell module can be suppressed.

[0042] (2) In the solar cell module described in (1) above, the decorative layer may be a coating film formed on the rear surface of the protective plate, the rear surface being opposite to the light incident side.

[0043] According to this configuration, in a solar cell module in which a common technique (painting) is used to enhance the aesthetic appearance, it is possible to effectively prevent a decrease in output due to a decorative layer.

[0044] (3) In the solar cell module described in (2) above, the coating film may be formed so as not to contact an edge of the protective plate.

[0045] According to this configuration, since the coating film is not present on the edge of the protective plate, the adhesive strength when bonding the protective plate and the sealing material is not reduced at the edge of the protective plate.

[0046] (4) The solar cell module described in (3) above may include a frame portion that is exposed and arranged along the outer edge of the protective plate, and the frame portion may be arranged so as not to overlap the decorative layer when the protective plate is viewed in the thickness direction.

[0047] With this configuration, even if the coating film is not present on the edge of the protective plate, resulting in a difference in color tone between the edge and other parts of the solar cell module, the unity of the entire module can be maintained by adjusting the color tone of the frame.

[0048] (5) In the solar cell module described in any one of (1) to (4) above, the plurality of power generating cells may be elongated, the plurality of power generating cells may be connected in a shingle to form the solar cell string, and the decorative layer may be formed and arranged at positions corresponding to both ends in the connection direction of the solar cell string formed by the shingle connection.

[0049] According to this configuration, in a solar cell string in which a plurality of power generating cells are connected in a shingled manner, each power generating cell is small and output reduction due to the effect of blocking or reducing the light emitted by the decorative layer is likely to occur, so that a countermeasure against output reduction due to the decorative layer can be effectively implemented in a solar cell module including such a solar cell string. Furthermore, regardless of whether the decorative layer blocks or reduces the light emitted by the decorative layer on either side of the connection direction of the shingled connection, output reduction of the solar cell module can be suppressed.

[0050] (6) The solar cell module described in any one of (1) to (5) above may further include a dummy cell that is not electrically connected to any of the plurality of power generating cells and does not contribute to power generation of the solar cell string, and the dummy cell may be positioned closer to the decorative layer than any of the plurality of power generating cells in a planar view.

[0051] According to this configuration, dummy cells that do not contribute to power generation are arranged in the solar cell string in the portion where sunlight is blocked or dimmed by the decorative layer, so that the power generation cells are not affected by the blocking or dimming of sunlight by the decorative layer, and the decrease in the power generation efficiency of the solar cell string can be more effectively prevented. [Explanation of symbols]

[0052] Reference Signs List 1... solar cell module, 2... solar cell string, 3... protective plate, 4... sealing material, 5... decorative layer, 6... frame, 7... resin sheet, 11... solar cell module, 20, 20a, 20b, 20c, 20d, 20e... power generating cell, 21... dummy cell, 22... front surface, 23... back surface, 30... front surface, 31... back surface, 32... edge, 120, 120a, 120b, 120c, 120d, 120e... power generating cell

Claims

1. A solar cell string is configured by connecting a plurality of elongated power generating cells in a single ring, the power generating cells generating power by receiving light; a light-transmitting protective plate overlapped on a light incident side of the solar cell string; a sealing material interposed between the solar cell string and the protection plate; a decorative layer that is formed on the light incident surface of the protective plate so as to be visible through the protective plate and that reduces or blocks light in a thickness direction; the decorative layer is formed between the protective plate and the solar cell string in a thickness direction, A solar cell module in which the decorative layer is formed and arranged at each of the positions corresponding to both ends in the connection direction of the solar cell string formed by the single ring connection, and the decorative layer is not formed and arranged at each of the positions corresponding to both ends in a direction perpendicular to the connection direction.

2. The solar cell module according to claim 1 , wherein the decorative layer is a coating film formed on the rear surface of the protective plate opposite to the light incident side.

3. The solar cell module according to claim 2 , wherein the coating film is formed so as not to contact an edge of the protective plate.

4. A frame portion is provided along an outer edge of the protective plate, The solar cell module according to claim 3 , wherein the frame portion is provided so as not to overlap the decorative layer when the protective plate is viewed in a thickness direction.

5. the solar cell string further includes a dummy cell that is not electrically connected to any of the plurality of power generating cells and does not contribute to power generation of the solar cell string, The solar cell module according to claim 1 , wherein the dummy cell is disposed at a position closer to the decorative layer than any of the plurality of power generating cells in a plan view.

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