solar cell module

Abstract

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 on the surface of a protective plate (glass).SOLUTION: A solar cell module includes a solar cell string, a translucent protective plate superimposed on the light incident side of the solar cell string, and a decorative layer that reduces or blocks light in the thickness direction and is formed on the surface of the protective plate on the light incident side, and the solar cell string includes a power generation cell that generates power by receiving light, and a dummy cell that is not electrically connected to the power generation cell and does not contribute to power generation of the solar cell string, and the dummy cell is arranged at a position closer to the decoration layer than the power generation cell in plan view.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a solar cell module. [Background technology]

[0002] 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 with the adhesive layer formed thereon. 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 this order on the solar cells, and a cover glass.

[0003] This solar cell module has multiple cell groups, each consisting of a row of solar cells. Furthermore, the solar cell module has the parts other than the multiple cell groups painted black, improving its appearance and design (paragraph 0090). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-170815 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if a black-painted area is provided on the light-receiving surface of such a solar cell module to conceal wiring materials and achieve a high level of design, direct sunlight may be incident at an angle relative to the normal direction of the solar cell module depending on the installation angle, orientation, and time of day. In such cases, the black-painted area (painted film) may block sunlight from some solar cells (power-generating cells). If the amount of light received by a solar cell whose sunlight is blocked by the painted film decreases, that cell may become a resistor within the module, reducing the power generation of cells other than that solar cell, and potentially preventing the desired output from being achieved. As a result, there is a risk that the power generation efficiency of the entire solar cell module, including solar cells whose sunlight is not blocked, may decrease.

[0006] An object of the present invention is to provide a solar cell module that can suppress a decrease in output even when a decorative layer such as a coating film is formed on the surface of a protective plate (glass). [Means for solving the problem]

[0007] The solar cell module of the present invention comprises a solar cell string, a translucent protective plate superimposed on the light incident side of the solar cell string, and a decorative layer formed on the light incident side surface of the protective plate, which reduces or blocks light in the thickness direction, wherein the solar cell string has power generating cells that generate electricity by receiving light, and dummy cells that are not electrically connected to the power generating cells and do not contribute to the power generation of the solar cell string, and the dummy cells are positioned closer to the decorative layer than the power generating cells in a planar view.

[0008] According to this configuration, since the dummy cells that do not contribute to power generation are arranged in the portion of the solar cell string where sunlight is blocked or dimmed by the decorative layer, the power generating cells are not affected by the blocking or dimming of sunlight by the decorative layer, and a decrease in the power generating efficiency of the solar cell string can be suppressed. In this way, a decrease in the power generating efficiency of the solar cell string due to the dummy cells can be suppressed, and a decrease in the output of the solar cell module can be suppressed.

[0009] In the solar cell module, the power generating cells and the dummy cells may have the same shape in plan view.

[0010] According to this configuration, the power generating cells and the dummy cells can be made to have the same appearance in a plan view, so that the appearance of the solar cell module is not marred even when the dummy cells are arranged.

[0011] In the solar cell module, the power generating cells may be elongated, and in the solar cell string, a plurality of the power generating cells may be connected in a shingled fashion.

[0012] With this configuration, in a solar cell string in which multiple power generating cells are connected in a single pattern, the individual power generating cells are small and output is likely to decrease due to the effects of blocking or dimming sunlight caused by the decorative layer. Therefore, in a solar cell module equipped with such a solar cell string, measures to prevent output reduction due to the decorative layer can be effectively taken.

[0013] In the solar cell module, the dummy cells may be arranged at both ends in a connection direction of the solar cell strings relating to the single connection.

[0014] With this configuration, even if sunlight is blocked or dimmed by the decorative layer on either side of the shingled connection, it is possible to cope with the reduction in output caused by the blocking or dimming of sunlight by the decorative layer.

[0015] In the solar cell module, the decorative layer may be a coating film formed on the surface of the protection plate.

[0016] According to this configuration, in a solar cell module in which a common technique (painting) is used to enhance the appearance, it is possible to effectively prevent a decrease in output due to a decorative layer.

[0017] In addition, in the solar cell module, the coating film may be a coating film in which a plurality of light-shielding regions and a plurality of light-transmitting regions are formed adjacent to each other on the surface of the protective plate, and the combination of the light-shielding regions and the light-transmitting regions reduces light in the thickness direction.

[0018] According to this configuration, in the solar cell module, the coating film that combines the light-shielding area and the light-transmitting area ensures a sense of unity when viewed from the outside, while partially letting in sunlight through the coating film, thereby mitigating the effects of sunlight blocking or dimming caused by the decorative layer, thereby effectively preventing output reduction caused by the decorative layer. [Effects of the Invention]

[0019] As described above, according to the present invention, it is possible to provide a solar cell module that can suppress a decrease in output even when a decorative layer such as a coating film is formed on the surface of the protective plate (glass). [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic plan view of a solar cell module according to this embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a schematic plan view of a solar cell module according to a comparative example. [Figure 4] FIG. 4 is a schematic cross-sectional view taken along the line IV-IV in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

[0022] As shown in Fig. 2, the solar cell module 1 includes a solar cell string 2, a light-transmitting protective plate 3 overlaid on the light incident side of the solar cell string 2, and a decorative layer 4 formed on the light incident side surface of the protective plate 3, which provides light reduction or light blocking in the thickness direction. The solar cell module 1 also includes a sealing material 5 provided between the solar cell string 2 and the protective plate 3. The solar cell module 1 also includes a frame 6 arranged on the outer edge of the protective plate 3. The solar cell module 1 is plate-shaped and is installed, for example, on the roof of a building such as a private home, with its main surface (light-receiving surface) facing upward (towards the sun).

[0023] The solar cell string 2 has power generating cells 20 that generate electricity by receiving light, and dummy cells 21 that are not electrically connected to the power generating cells 20 and do not contribute to power generation by the solar cell string 2. In the solar cell string 2, the dummy cells 21 are arranged closer to the decorative layer 4 than the power generating cells 20 in a plan view, as shown in Fig. 1 .

[0024] On the other hand, in the solar cell module 11 according to the comparative example, as shown in Fig. 3 and Fig. 4, the solar cell string 12 does not include a dummy cell, and is composed only of power generating cells 120. Therefore, sunlight is blocked by the decorative layer 4 for some of the power generating cells 120. Specifically, in this solar cell module 11, the decorative layer 4 blocks all or part of the sunlight incident on the power generating cells 120a, 120b that are close to the decorative layer 4 in a plan view (see Fig. 4). If the amount of light received by the power generating cells 120a, 120b that have sunlight blocked by the decorative layer 4 decreases, the power generating cells 120a, 120b become resistors within the solar cell module 11, and the amount of power generated by the power generating cells 120c, 120d, and 120e other than the power generating cells 120a, 120b in this solar cell module 11 also decreases, resulting in a phenomenon in which the desired output cannot be secured. As described above, there is a risk that the power generation efficiency of the entire solar cell module 11, including the power generation cells 120c, 120d, and 120e that are not blocked by the influence of the decorative layer 4, will decrease.

[0025] In contrast, according to the solar cell module 1 of this embodiment, dummy cells 21 that do not contribute to power generation are arranged in the solar cell string 2 in the portion where sunlight is blocked or dimmed by the decorative layer 4 (see FIG. 2 ), so that the power generating cells 20 are not affected by the blocking or dimming of sunlight by the decorative layer 4, and it is possible to suppress a decrease in the power generation efficiency of the solar cell string 2. In this way, the dummy cells 21 can suppress a decrease in the power generation efficiency of the solar cell string 2, and therefore a decrease in the output of the solar cell module 1 can be suppressed.

[0026] In addition, in this solar cell string 2, the power generating cells 20 and the dummy cells 21 have the same shape at least in a plan view (see FIG. 1). 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. This allows the power generating cells 20 and the dummy cells 21 to have the same appearance when viewed through the protective plate 3 in a plan view, so the appearance of the solar cell module 1 is not impaired even when the dummy cells 21 are placed.

[0027] Furthermore, in the solar cell string 2, each power generating cell 20 has an elongated shape, and the plurality of power generating cells 20 are shingled-connected. The shingled 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 roofing shingles. In the solar cell string 2 in which the plurality of power generating cells 20 are shingled-connected in this manner, each power generating cell 20 is smaller than in other connection methods, and output reduction due to the effects of sunlight shading or dimming caused by the decorative layer 4 is more likely to occur. Therefore, in a solar cell module 1 including such a solar cell string 2, countermeasures against output reduction caused by the decorative layer 4 can be effectively implemented.

[0028] The solar cell string 2 has at least one power generating cell 20, and specifically has a plurality of power generating cells 20. Each power generating cell 20 has the same size (in the solar cell string 2 connected in a single ring, the width dimension of each power generating cell 20). Each power generating cell 20 is, for example, in the shape of a rectangular plate.

[0029] Furthermore, the solar cell string 2 has at least one dummy cell 21, and specifically, has a plurality of dummy cells 21. The size of each dummy cell 21 (in the solar cell string 2 connected in a single ring), is the same (the width dimension of each dummy cell 21).

[0030] The dummy cells 21 may be, for example, resin plates or metal plates. Furthermore, the dummy cells 21 may have the same configuration as the power generating cells 20 and may not be electrically connected to other power generating cells 20. Furthermore, the dummy cells 21 are arranged at positions that do not overlap with the decorative layer 4 in a plan view.

[0031] In this solar cell string 2, the shapes of the power generating cells 20 and the dummy cells 21 are also the same in cross section (see FIG. 2). The shapes of the power generating cells 20 and the dummy cells 21 can be made different to the extent that the appearance of the solar cell module 1 is not impaired. For example, when the power generating cells 20 and the dummy cells 21 have the same shape in plan view, the shape and size of the power generating cells 20 may be different from the shape and size of the dummy cells 21.

[0032] Furthermore, in this solar cell string 2, dummy cells 21 are arranged over the entire area where sunlight is blocked or reduced by the decorative layer 4. The areas where sunlight is blocked or reduced by the decorative layer 4 are areas shaded with dots in Fig. 2. Specifically, dummy cells 21 are arranged at both ends in the connection direction of the solar cell string 2 in the shingled connection (both ends in the left-right direction in Fig. 1). This makes it possible to address the reduction in output caused by sunlight blocking or reduction in brightness by the decorative layer 4, regardless of which side in the connection direction of the shingled connection sunlight is blocked or reduced by the decorative layer 4.

[0033] In addition, when the direction of sunlight toward the solar cell module 1 is fixed, i.e., when it is fixed that sunlight is blocked or dimmed by the decorative layer 4 on one side of the connection direction of the shingled connection, a dummy cell 21 may be placed at one end of the connection direction of the solar cell string 2 related to the shingled connection (one end in the left-right direction in Figure 1).

[0034] 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. In the solar cell module 1 of this 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.

[0035] The decorative layer 4 is, for example, a coating film formed on the surface 30 (the surface located on the light incident side) of the protective plate 3. Therefore, the decorative layer 4 can be an effective measure against output reduction in a solar cell module 1 that uses a common technique (painting) to enhance its appearance.

[0036] The decorative layer 4 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. Specifically, the decorative layer 4 is a coating film with a thickness of 5 μm to 50 μm. This coating film is formed, for example, by ceramic printing. The decorative layer 4 is a coating film that blocks incident light or transmits (attenuates) a certain amount of incident light. In the solar cell module 1 of this embodiment, the decorative layer 4 is a black coating film, but it may be a coating film of another color.

[0037] The decorative layer 4 is, for example, a coating film in which a predetermined area is solidly painted (solid-coated). The decorative layer 4 may be a coating film in which multiple light-shielding areas and multiple light-transmitting areas are adjacently formed on the surface of the protective plate 3, thereby reducing light in the thickness direction through the combination of the light-shielding and light-transmitting areas. Specifically, the decorative layer 4 may be a coating film in which a predetermined area is painted in a dotted or meshed pattern. The shape of each dot in a dotted or meshed coating film and the shape of the mesh in a meshed coating film are not particularly limited and can be various shapes. In this case, the dotted or meshed coating film ensures a sense of unity when viewed from the outside, while partially allowing sunlight to enter through the coating film, thereby reducing the shading rate and mitigating the effects of sunlight shading or light reduction by the decorative layer 4. This effectively prevents output reduction due to the decorative layer 4. The light transmittance of the coating film can be adjusted by adjusting the area ratio between the light-shielding areas, where a coating material such as paint is arranged in a dotted or meshed pattern, and the light-transmitting areas, where no coating material is arranged. The decorative layer 4 may be a light-shielding material other than a coating film, such as a black or other color film.

[0038] The decorative layer 4 is disposed on the outer edge of the protective plate 3 and is a separate member from the frame 6 provided to shape and reinforce the solar cell module 1. Therefore, as will be described later, the shadow cast by the decorative layer 4 and the shadow cast by the frame 6 are completely different.

[0039] The sealing material 5 is, for example, overlaid on each of the front surface 22 and the back surface 23 of the solar cell string 2. The sealing material 5 is, for example, a resin layer. The sealing material 5 also covers the end surfaces (outer peripheries) of the solar cell string 2. Specifically, the sealing material 5 continuously covers the front surface 22, the back surface 23, and the end surfaces of the solar cell string 2.

[0040] Samples of the above solar cell module 1 were prepared in which the number of dummy cells 21 provided on one side in the connection direction of the solar cell string 2 in the shingled connection was varied from 0, 1, 2, and 3, and a simulation was performed to calculate the amount of power generated. In these solar cell modules 1, the width of the power generating cells 20 was 24 mm, and the thickness of the protective plate 3 (glass plate) was 6 mm. The solar cell module 1 was also installed at a 90-degree angle and facing 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.

[0041] In this simulation, calculations were made assuming that when direct or quasi-direct light is blocked by the decorative layer 4, the direct or quasi-direct light is attenuated by the proportion of light that falls on the dummy cell 21 or 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 normal year value data for Fukuoka from the Annual Hourly Solar Radiation Database (METPV-11).

[0042] As a result of this simulation, the annual power generation per 1kW installation was 653kWh when there were no dummy cells 21, 755kWh when there was one dummy cell 21, 762kWh when there were two dummy cells 21, and 763kWh when there were three dummy cells 21. Thus, the results showed that by providing at least one dummy cell 21 on one side of the connection direction of the solar cell string 2 in a single connection, the power generation amount increased by about 16%.

[0043] Furthermore, in the solar cell module 1 described above, the shading or dimming of sunlight by the decorative layer 4 occurs inside the module, and therefore the decorative layer 4 does not cast a visually (appearance-wise) recognizable shadow (shadow outside the module) on the solar cell module 1, such as a shadow cast by the frame 6. Therefore, the issue of reduced output of the solar cell module 1 due to the shading or dimming of sunlight by the decorative layer 4 (a "shadow that is completed inside the module" that is difficult to recognize visually from outside the module) has not received attention until now, and is a new issue that was first discovered by the inventors of the present application.

[0044] Furthermore, the inventors of the present application were only able to estimate the extent of the influence of the decorative layer 4 on blocking or reducing sunlight throughout the year after actually performing the following simulations. Therefore, even for a person skilled in the art, it would not be easy to arrive at the configuration of the combination of the decorative layer 4 (coating film) and dummy cells 21 in this embodiment after performing such simulations.

[0045] Below, we will explain a simulation to calculate the length of the portion of the solar cell module 1 that is shaded or dimmed by the decorative layer 4 (coating film) (the dimension in the connection direction of the solar cell string 2 in a shingled connection). In these solar cell modules 1, the width of the power generating cells 20 is 25 mm, and the thickness of the protective plate 3 (glass plate) is 6 mm. The solar cell modules 1 were also installed vertically (90 degrees) and faced south. Furthermore, the solar radiation amount used in the simulation was the normal year value data for Osaka from the Annual Hourly Solar Radiation Database (METPV-11).

[0046] The simulation results are shown in Table 1 below. × indicates times when direct sunlight does not reach the module. Additionally, negative values ​​indicate that sunlight is blocked or dimmed on the west side of the coating, while positive values ​​indicate that sunlight is blocked or dimmed on the east side of the coating.

[0047] [Table 1]

[0048] As a result of this simulation, for example, at 1:30 pm on June 20th in Osaka, It was found that when a module with a 6 mm thick protective plate 3 on the light-receiving surface side is installed vertically facing south, a 10.7 mm wide area of ​​sunlight is blocked or dimmed east of the coating. When sunlight is blocked or dimmed in this way, if a solar cell string 2 composed of electrically connected cells each 25 mm wide is placed closely to the coating (when the solar cell string 2 is composed only of power-generating cells 20), direct sunlight is blocked or dimmed in 42.8% of the area of ​​the power-generating cells 20 placed closest to the coating, thereby reducing the overall power generation of the module. On the other hand, when dummy cells 21 of the same dimensions as the power-generating cells 20 but not electrically connected to them are placed between the coating and the solar cell string 2 (when the solar cell string 2 includes dummy cells 21, as in solar cell module 1), sunlight is not blocked or dimmed in the electrically connected power-generating cells 20, and therefore no reduction in power generation occurs.

[0049] The solar cell module of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, or 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.

[0050] In the solar cell module 1 of the above embodiment, dummy cells 21 were arranged over the entire area of ​​the solar cell string 2 where sunlight is blocked or reduced by the decorative layer 4. However, dummy cells 21 may be arranged in part of this area, with a space (empty space) provided in the remaining area. For example, in the solar cell module 1 of FIG. 2, two dummy cells 21 are provided. However, a space (empty space) may be provided in place of one of the two dummy cells 21. Note that a sealing material 5 is disposed in this space. Furthermore, in the solar module 1 of the above embodiment, the dummy cells 21 are arranged in a position that does not overlap with the decorative layer 4 in a plan view. However, a portion of the dummy cells 21 may be arranged in a position that overlaps with the decorative layer 4 in a plan view. This configuration has the advantage of increasing the degree of freedom in the arrangement of each area relative to the determined size (glass size) of the protective plate 3.

[0051] Furthermore, in the solar cell string 2 of the above embodiment, the size of each power generating cell 20 is the same, but the size may be different. For example, the size (width dimension of the power generating cells 20 connected in a single connection) of the power generating cell 20 arranged near the dummy cell 21 can be made larger than the size of the other power generating cells 20. In this case, even if sunlight is blocked or reduced by the decorative layer 4 in some of the power generating cells 20 arranged near the dummy cell 21, the area of ​​the light-receiving surface of the power generating cell 20 that is actually hit by the light can be secured, so that a decrease in output due to the influence of sunlight blocking or reduction in light by the decorative layer 4 is unlikely to occur.

[0052] The solar cell module 1 in the above embodiment is installed with the main surface (light-receiving surface) facing upward, for example. However, it may also be attached to a vertical surface or a surface close to a vertical surface (for example, a surface inclined at an angle of 15° or less from the vertical), such as the exterior wall of a private home. 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 6. In a solar cell module 1 equipped with a mounting portion, as long as the power-generating cells 20 and the dummy cells 21 have the same shape at least in a plan view, when the solar cell module 1 is installed on a vertical surface using the mounting portion, there is no aesthetic problem even if the solar cell strings 2, which are in an easily visible position, are visible through the protective plate 3.

[0053] In the solar cell string 2 of the above embodiment, the power generating cells 20 have an elongated shape, and the plurality of power generating cells 20 are connected in a single ring. However, the shape of the power generating cells 20 may be a shape other than an elongated shape, such as a square plate, and the plurality of power generating cells 20 may not be connected in a single ring, but may be connected by wiring material. [Explanation of symbols]

[0054] 1... solar cell module, 2... solar cell string, 3... protective plate, 4... decorative layer, 5... sealing material, 6... frame, 7... resin sheet, 11... solar cell module, 12... solar cell string, 20... power generating cell, 21... dummy cell, 22... front surface, 23... back surface, 30... front surface, 120, 120a, 120b, 120c, 120d, 120e... power generating cell

Claims

1. a solar cell string; a light-transmitting protective plate overlaid on the light incident side of the solar cell string; a frame portion disposed on the outer edge of the protection plate; a decorative layer formed on the light incident side surface of the protective plate, the decorative layer being a separate member from the frame portion and reducing or blocking light in a thickness direction; The outer edge of the protective plate is rectangular having vertical and horizontal sides, The frame portion is disposed along vertical and horizontal sides of the outer edge of the protection plate, The decorative layer is disposed along only a vertical side of the outer edge of the protective plate, the solar cell string includes a power generating cell that generates power by receiving light, and a dummy cell that is not electrically connected to the power generating cell and does not contribute to power generation of the solar cell string; The dummy cell is disposed closer to the decorative layer than the power generating cell in a plan view.

2. The solar cell module according to claim 1 , wherein the power generating cells and the dummy cells have the same shape in plan view.

3. The power generating cell has an elongated shape, The solar cell module according to claim 1 or 2, wherein the solar cell string includes a plurality of the power generating cells connected in a single ring.

4. The solar cell module according to claim 3 , wherein the dummy cells are arranged at both ends of the solar cell string relating to the single-ring connection in a connection direction.

5. 5. The solar cell module according to claim 1, wherein the decorative layer is a coating film formed on the surface of the protective plate.

6. 6. The solar cell module according to claim 5, wherein the coating film is a coating film in which a plurality of light-shielding regions and a plurality of light-transmitting regions are formed adjacent to each other on the surface of the protective plate, and the combination of the light-shielding regions and the light-transmitting regions reduces light in the thickness direction.

7. A solar cell string; a light-transmitting protective plate overlaid on the light incident side of the solar cell string; a decorative layer formed on the light incident side surface of the protective plate, the decorative layer reducing or blocking light in a thickness direction; the solar cell string includes an elongated power generating cell that generates power by receiving light, and a dummy cell that is not electrically connected to the power generating cell and does not contribute to power generation of the solar cell string; In the solar cell string, a plurality of the power generating cells are connected in a single connection, The dummy cells are positioned closer to the decorative layer than the power generating cells in a planar view, and are arranged at both ends of the solar cell string related to the shingling connection in the connection direction, but are not arranged at both ends of the solar cell string related to the shingling connection in the direction perpendicular to the connection direction.

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