Solar battery cell and solar battery module

Abstract

Provided is a solar battery cell having excellent design properties. The solar battery cell (40) comprises a coating layer (5) applied on at least a linear portion of the peripheral edge of a light-receiving surface (12) of the solar battery cell (40). The solar battery cell (40) is characterized in that the light-receiving surface (12) thereof includes an anti-reflection film, the coating layer (5) is formed on the anti-reflection film, and the color of the coating layer (5) is the same color as or a color similar to the color of the light-receiving surface (12) of the solar battery cell (40).

Description

Solar cell and solar module

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

[0002] In recent years, solar cells have been widely used in various places other than on residential roofs and solar power plants. For example, solar cell modules installed on vehicle roofs are more visible to users than those installed on residential roofs or power plants, and therefore require a higher level of design quality than conventional solar cell modules. To improve the design quality of solar cell modules, a solar cell module is known in which a black pattern is provided on the light-receiving-side protective member so as to overlap the gaps between the solar cell cells, thereby obscuring the gaps (see, for example, Patent Document 1).

[0003] WO2020 / 121693A1

[0004] Solar cells typically have an anti-reflective coating and / or an anti-reflective textured structure on their light-receiving surfaces, resulting in a dark blue or black color. If a solar cell has chipping (a chip at the corner between the light-receiving surface and the peripheral side) on its periphery, the anti-reflective coating and / or anti-reflective textured structure disappears in the chipped area, revealing the original semiconductor surface and reflecting light. For solar cell modules installed on residential roofs, solar power plants, and other such locations, chipping is inconspicuous because they are installed at high altitudes or in areas with little foot traffic. However, for solar cell modules mounted on vehicles, chipping is highly noticeable because the solar cell can be viewed up close. For example, even chipping as small as 0.1 mm to 1.0 mm in size is easily detectable in solar cell modules mounted on vehicles. Therefore, high appearance requirements are placed on solar cell modules installed in close proximity to users, such as those mounted on vehicles, and the solar cells that make up the solar cell module require high design quality. Furthermore, dirt, watermarks, color unevenness, etc. on the light-receiving surface of a solar cell degrade the design quality of the solar cell, just like chipping. When appearance requirements are high, solar cells with poor design quality are removed from the production line during visual inspection, reducing the appearance yield. As mentioned above, defects that reduce the design quality of solar cells include chipping, dirt, watermarks, and color unevenness, all of which have been found to occur more frequently around the edges of solar cells. For example, chipping is likely to occur during the solar cell manufacturing process when semiconductor substrates are placed in cassettes or deposition trays, or when the edges of transported semiconductor substrates or solar cells hit guide pins. Small chipping (e.g., chips of 3 mm or less) occurs frequently. Furthermore, when semiconductor substrates are placed in cassettes or deposition trays, or when the edges of transported semiconductor substrates or solar cells hit guide pins, dirt (e.g., oil) may adhere to the edges of semiconductor substrates or solar cells. Furthermore, during the drying process after wet processing of semiconductor substrates, water droplets remaining between the cassette guide and the semiconductor substrate may cause watermarks around the edges of the semiconductor substrates.Furthermore, when forming an anti-reflection film on the surface of a semiconductor substrate, uneven film formation is likely to occur at the peripheral edge of the semiconductor substrate, and color unevenness may occur due to differences in the thickness of the anti-reflection film. One possible method for using solar cells with defects at the peripheral edge that reduce design aesthetics is to provide a black pattern on the light-receiving-side protective member so that it overlaps the edge of the solar cell, as described in Patent Document 1. However, consideration must be given to the positional accuracy when placing the solar cell on the light-receiving-side protective member, tolerances such as the amount of cell misalignment during lamination, and the appearance from an oblique angle, making it necessary to increase the area of ​​the black pattern by an amount corresponding to the margin. This results in a problem of reduced light reception and reduced power generation by the solar cell. The present invention was made in consideration of these circumstances and provides a solar cell with high design aesthetics.

[0005] The present invention provides a solar cell characterized in that it has a paint layer applied to at least a linear portion of the periphery of the light-receiving surface of the solar cell, the solar cell has an anti-reflection film on its light-receiving surface, the paint layer is formed on the anti-reflection film, and the color of the paint layer is the same color or a similar color to the color of the light-receiving surface of the solar cell.

[0006] According to the present invention, the design of the solar cell is improved.

[0007] (a) is a schematic plan view of a solar cell according to one embodiment of the present invention, and (b) is a schematic back view of this solar cell. (a) and (b) are each schematic plan views of a solar cell according to one embodiment of the present invention. (a) is a schematic cross-sectional view of a solar cell taken along dashed line A-A in FIG. 1, and (b) is a schematic cross-sectional view of a solar cell comprising a semiconductor substrate having chipping at its edge. An explanatory diagram of chipping. (b) is a schematic plan view of a solar cell module according to one embodiment of the present invention. (c) is a schematic cross-sectional view of a solar cell module taken along dashed line B-B in FIG. (d) are explanatory diagrams of a method for manufacturing a solar cell module according to one embodiment of the present invention.

[0008] The solar cell of the present invention is characterized in that it comprises a paint layer applied to at least a linear portion of the periphery of the light-receiving surface of the solar cell, the color of the paint layer being the same or a similar color to the color of the light-receiving surface of the solar cell. The solar cell of the present invention is also characterized in that it comprises a paint layer applied to at least a linear portion of the periphery of the light-receiving surface of the solar cell, the solar cell has an anti-reflection film on its light-receiving surface, the paint layer is formed on the anti-reflection film, and the color of the paint layer is the same or a similar color to the color of the light-receiving surface of the solar cell. The solar cell of the present invention is also characterized in that it comprises a paint layer applied to at least a linear portion of the periphery of the light-receiving surface of the solar cell, electrodes are disposed only on the back surface of the solar cell, and the color of the paint layer is the same or a similar color to the color of the light-receiving surface of the solar cell.

[0009] The solar cell preferably includes a silicon substrate, and the color of the coating layer is preferably black or dark blue. An electrode is preferably disposed only on the back surface of the solar cell (back-contact solar cell). A back-contact solar cell, in which no electrode is disposed on the light-receiving surface of the solar cell, eliminates the electrode on the light-receiving surface, improving the design of the solar cell. The width of the coating layer disposed along the edge of the light-receiving surface of the solar cell is preferably 3 mm or less. This enhances the design of the solar cell and suppresses a reduction in the light-receiving area. When the shape of the solar cell is a rectangle with at least two rounded corners in a plan view, the coating layer is disposed on the linear portions of the four sides of the periphery of the light-receiving surface of the solar cell, and does not necessarily have to be disposed on the rounded corners of the periphery of the light-receiving surface of the solar cell. This enhances the design of the solar cell and makes it easy to form the coating layer.

[0010] The present invention also provides a solar cell module comprising a plurality of solar cells of the present invention, a light-receiving surface protective member, and a back surface protective member. The solar cell module of the present invention has high designability because it is composed of solar cells with high designability. The present invention also provides a solar cell module comprising a plurality of solar cells of the present invention, wiring, a light-receiving surface protective member, a back surface protective member, and a wiring cover covering at least a portion of the wiring, wherein the wiring connects two adjacent solar cells, and the plurality of solar cells are arranged between the light-receiving surface protective member and the back surface protective member, the color of the surface of the back surface protective member facing the solar cells being the same color or a similar color to the color of the light-receiving surface of the solar cells, and the color of the surface of the wiring cover facing the light-receiving surface being the same color or a similar color to the color of the light-receiving surface of the solar cells. The solar cell module of the present invention has high designability because the light-receiving surface appears to be a single color.

[0011] The present invention will be described in more detail below with reference to several embodiments. The configurations shown in the drawings and the following description are examples, and the scope of the present invention is not limited to those shown in the drawings and the following description.

[0012] First Embodiment FIG. 1(a) is a schematic plan view of a solar cell according to this embodiment, and FIG. 1(b) is a schematic back view of the solar cell. FIGS. 2(a) and 2(b) are schematic plan views of a solar cell according to a modified example of this embodiment. FIG. 3(a) is a schematic cross-sectional view of the solar cell taken along dashed line A-A in FIG. 1, and FIG. 3(b) is a schematic cross-sectional view of a solar cell including a semiconductor substrate having a chipped edge. A solar cell 40 according to this embodiment includes a semiconductor substrate 2, a light-receiving surface 12, a back surface 13, a first electrode 3, a second electrode 4, and a coating layer 5 applied to at least a linear portion of the periphery of the light-receiving surface 12. The semiconductor substrate 2 has a first-conductivity-type region or a first-conductivity-type diffusion region 6 and a second-conductivity-type region or a second-conductivity-type diffusion region 7. The first electrode 3 is connected to the first-conductivity-type region or the first-conductivity-type diffusion region 6, and the second electrode 4 is connected to the second-conductivity-type region or the second-conductivity-type diffusion region 7. Solar cell 40 has at least one of an anti-reflection coating 9 and an anti-reflection texture structure 10 on its light-receiving surface 12. Anti-reflection coating 9 is a film laminated on the light-receiving surface of semiconductor substrate 2. Anti-reflection texture structure 10 is an uneven structure formed on the light-receiving surface of semiconductor substrate 2. The color of coating layer 5 is the same color or a similar color to the color of light-receiving surface 12 of solar cell 40. The colors of light-receiving surface 12, coating layer 5, etc. can be quantified using a colorimeter.

[0013] The semiconductor substrate 2 is a semiconductor substrate, such as a single-crystal silicon substrate, a polycrystalline silicon substrate, or a III-V compound semiconductor substrate. The solar cell 40 includes the semiconductor substrate 2 and has a p-n junction capable of generating photovoltaic power. The semiconductor substrate 2 included in the solar cell 40 is not particularly limited. The semiconductor substrate 2 of this embodiment includes, for example, a first-conductivity region or a first-conductivity-type diffusion region 6 and a second-conductivity region or a second-conductivity-type diffusion region 7. The first or second-conductivity region may be a base material region of the semiconductor substrate (e.g., when a p-type semiconductor substrate is used as the base material, the p-type semiconductor region inherent in this substrate) or a deposited film deposited on the base material substrate. The semiconductor substrate may also have both a diffusion region and a deposited film. One of the first and second conductivity types is n-type (majority carriers are electrons), and the other is p-type (majority carriers are holes). These regions form a p-n junction in the semiconductor substrate 2. When the semiconductor substrate 2 is a silicon substrate, the p-type diffusion region (one of the first conductivity type diffusion region 6 and the second conductivity type diffusion region 7) is a region in which a p-type dopant such as boron (B) is diffused, and the n-type diffusion region (the other of the first conductivity type diffusion region 6 and the second conductivity type diffusion region 7) is a region in which an n-type dopant such as phosphorus (P) is diffused.

[0014] The solar cell 40 has an anti-reflection structure on the light-receiving surface 12. For example, the solar cell 40 has at least one of an anti-reflection film 9 and an anti-reflection textured structure 10 on the light-receiving surface 12. This causes the light-receiving surface 12 of the solar cell 40 to be dark blue or black. The anti-reflection textured structure 10 is a textured, uneven structure that guides light incident on the light-receiving surface 12 into the semiconductor. The anti-reflection textured structure 10 is formed on the light-receiving surface of the semiconductor substrate 2. The anti-reflection film 9 is a dielectric film such as a silicon nitride film or a silicon oxide film. The anti-reflection film 9 may also have a structure in which multiple dielectric films with different refractive indices are stacked. The anti-reflection film 9 is stacked on the light-receiving surface of the semiconductor substrate 2. The solar cell 40 may also have a passivation film 23 on the back surface. The passivation film 23 is stacked on the surface (back surface) of the semiconductor substrate 2 opposite the light-receiving surface.

[0015] The shape of the semiconductor substrate 2 (solar cell 40) may be a square with rounded corners as shown in Figures 1 and 2(a), or a rectangle, or may be a shape obtained by dividing a square semiconductor substrate with rounded corners into two as shown in Figure 2(b).

[0016] The first electrode 3 and the second electrode 4 are electrodes for extracting photovoltaic power generated in the semiconductor substrate 2. The first electrode 3 is connected to the first-conductivity-type region or the first-conductivity-type diffusion region 6, and the second electrode 4 is connected to the second-conductivity-type region or the second-conductivity-type diffusion region 7. One of the first electrode 3 and the second electrode 4 may be provided on the light-receiving surface 12 of the semiconductor substrate 2, and the other may be provided on the back surface of the semiconductor substrate 2 (double-sided electrode solar cell). Alternatively, as shown in Figures 1 to 3, both the first electrode 3 and the second electrode 4 may be provided on the back surface of the semiconductor substrate 2 (back-contact solar cell). Back-contact solar cells have high design flexibility because they do not have electrodes on the light-receiving surface 12. The first electrode 3 is linear, and the second electrode 4 is linear. Furthermore, the linear first electrodes 3 and second electrodes 4 are alternately arranged on the back surface of the semiconductor substrate 2. The linear first electrode 3 is connected to a first cell terminal 25 provided on the back surface of the semiconductor substrate 2, and the linear second electrode 4 is connected to a second cell terminal 26 provided on the back surface of the semiconductor substrate 2. Photovoltaic power generated in the semiconductor substrate 2 can be extracted to the outside via the first cell terminal 25 and the second cell terminal 26.

[0017] The semiconductor substrate 2 included in the back-contact solar cell can have a structure in which linear first-conductivity-type diffusion regions 6 formed by linearly diffusing a first-conductivity-type dopant on the back surface side of a semiconductor region 8 (p-type semiconductor region, n-type semiconductor region, or intrinsic semiconductor region) and linear second-conductivity-type diffusion regions 7 formed by diffusing a second-conductivity-type dopant on the back surface side of the semiconductor region 8 are arranged alternately. The linear first electrode 3 can be connected to the linear first-conductivity-type diffusion region 6 through a linear opening provided in a passivation film 23 on the back surface 13 of the semiconductor substrate 2. The linear second electrode 4 can be connected to the linear second-conductivity-type diffusion region 7 through a linear opening provided in the passivation film 23 on the back surface 13 of the semiconductor substrate 2.

[0018] The coating layer 5 is a layer formed by applying paint onto the light-receiving surface of the solar cell 40. The coating layer 5 may contain a pigment and a resin. The pigment contained in the coating layer 5 is preferably a light-resistant pigment. This makes it possible to prevent discoloration of the coating layer 5. The coating used to form the coating layer 5 contains, for example, a pigment, a resin, and a solvent. The method for applying paint onto the light-receiving surface of the solar cell 40 to form the coating layer 5 is not particularly limited, but examples include an inkjet method, a spray coating method, a transfer method, and a screen printing method. The coating layer 5 may be provided so as to be in contact with the anti-reflection film 9.

[0019] The coating layer 5 is a layer applied to at least linear portions of the periphery of the light-receiving surface 12 of the solar cell 40. In this embodiment, the coating layer 5 is provided on an anti-reflection film 9 formed on the semiconductor substrate 2. By providing such a coating layer 5, even if chipping 28 (a chip at the corner between the light-receiving surface 12 and the peripheral side surface 14, see FIGS. 4( a ) and 4 ( b )), dirt, watermarks, color unevenness, etc., occurs on the periphery of the light-receiving surface 12 of the solar cell 40, these are hidden by the coating layer 5, preventing a decrease in the design quality of the solar cell 40. Furthermore, even if chipping 28, dirt, watermarks, color unevenness, etc., occurs on the periphery of the light-receiving surface 12 of the solar cell 40, they are hidden by the coating layer 5, so they do not cause appearance defects of the solar cell 40 and can improve appearance yield. The coating layer 5 may also be provided on the entire periphery of the light-receiving surface 12, as shown in FIG. 1( a ).

[0020] As shown in Figures 2(a) and 2(b), the coating layer 5 is applied to the linear portions of the periphery of the light-receiving surface 12, but does not necessarily have to be applied to the rounded corners of the periphery of the light-receiving surface 12. Chipping, stains, watermarks, color unevenness, and the like are likely to occur on the linear portions of the periphery of the light-receiving surface 12, but are less likely to occur on the rounded corners (for example, due to contact between the linear portions of the semiconductor substrate 2 and guide pins during the manufacturing process). Therefore, applying the coating layer 5 to the linear portions of the periphery of the light-receiving surface 12 can prevent a decrease in the design quality of the solar cell 40 and improve the appearance yield. It can also prevent a reduction in the amount of light incident on the solar cell 40. Furthermore, since only the linear portions of the periphery of the light-receiving surface 12 need to be coated, coating is easy.

[0021] The color of the coating layer 5 is the same color or a similar color to the color of the light-receiving surface 12 of the solar cell 40. Therefore, the light-receiving surface of the solar cell 40 (excluding the electrodes, if any) appears to be a single color, improving the design of the solar cell 40 and increasing the appearance yield. The light-receiving surface 12 of the solar cell 40, which includes a semiconductor substrate 2 (silicon substrate) and has an anti-reflection film 9 or anti-reflection texture structure 10 on the light-receiving surface, is usually black to dark blue. Therefore, the color of the coating layer 5 is black to dark blue. The color of the coating layer 5 may also be a single color. L * a * b * The color difference ΔE between the color of the paint layer 5 and the color of the light-receiving surface 12 of the solar cell 40 in the color space (color system) * is, for example, from 0.0 to 10.0, preferably from 0.0 to 5.0, and more preferably from 0.0 to 2.0. The color difference can be measured using a colorimeter, a colorimeter, a color difference meter, or the like.

[0022] The coating layer 5 is linear and is provided in a linear region between the edge (end) of the light-receiving surface 12 of the solar cell 40 and a line along the edge (end) of the light-receiving surface 12 of the solar cell 40. The width of the linear coating layer 5 (distance from the edge of the light-receiving surface) is 3 mm or less, preferably 2 mm or less, preferably 1 mm or less, and more preferably 0.5 mm or less. This allows chipping, dirt, watermarks, color unevenness, etc. to be hidden, and also prevents a decrease in the amount of light incident on the semiconductor substrate 2, thereby preventing a decrease in power generation. It also allows for the hiding of chipping of 3 mm or less, which frequently occurs. The thickness of the coating layer 5 is, for example, 0.5 μm or more and 10 μm or less.

[0023] Second Embodiment FIG. 5 is a schematic plan view of a solar cell module according to this embodiment, and FIG. 6 is a schematic cross-sectional view of the solar cell module taken along dashed line B-B in FIG. 5 . The solar cell module 50 includes a plurality of solar cells 40 according to the first embodiment, wiring 16, a light-receiving surface protection member 17, a back surface protection member 18, and a wiring cover 20 that covers at least a portion of the wiring 16. The solar cells 40 were described in the first embodiment and will not be described here. The number of solar cells 40 included in the solar cell module 50 is not particularly limited. For example, the solar cell module 50 shown in FIGS. 5 and 6 includes six solar cell strings, each of which has five solar cells 40 connected in series. All solar cells 40 included in the solar cell module 50 may have substantially the same shape. Furthermore, the coating layers 5 of all solar cells 40 included in the solar cell module 50 may have substantially the same pattern. This allows for a uniform appearance of the solar cells 40, thereby improving the design of the solar cell module 50. Furthermore, the light receiving areas of the cells can be made uniform, and variations in the output current values ​​of the solar battery cells 40 can be suppressed.

[0024] Of two adjacent solar cells 40 included in a solar cell string, a first cell terminal 25 of one solar cell 40 and a second cell terminal 26 of the other solar cell 40 are connected by a wiring 16. Furthermore, the cell terminals at both ends of the solar cell string are connected to different bus bars 15 by the wiring 16. Furthermore, the bus bars 15 are connected to terminal boxes provided on the rear surface of the adjacent solar cell string and / or the solar cell module 50.

[0025] At least the inter-cell wiring of the wiring 16 is covered with a wiring cover 20 at least on the light receiving surface side. Also, at least the light receiving surface side of the bus bar 15 may be covered with the wiring cover 20. The wiring cover 20 may be in a sheet form or may be a coating layer for the wiring 16. Note that in the solar cell module 50 shown in Figs. 5 and 6, the wiring cover 20 is a coating layer for the wiring 16 and the bus bar 15. The color of the surface on the light receiving surface side of the wiring cover 20 is the same color or a similar color as the color of the light receiving surface 12 of the solar cell 40. The color of the surface on the light receiving surface side of the wiring cover 20 is, for example, black or dark blue. Also, L * a * b * The color difference ΔE between the color of the surface on the light-receiving side of the wiring cover 20 and the color of the light-receiving surface of the solar cell 40 in the color space (color system) * is, for example, from 0.0 to 10.0, preferably from 0.0 to 5.0, and more preferably from 0.0 to 2.0. The color difference can be measured using a colorimeter, a colorimeter, a color difference meter, or the like.

[0026] The plurality of solar cells 40 are disposed between a light-receiving surface protective member 17 and a back surface protective member 18, and are sealed with a sealing material 22. The light-receiving surface protective member 17 is a translucent protective member disposed on the light-receiving surface side of the plurality of solar cells 40, and is, for example, a glass plate such as thermally strengthened white glass or chemically strengthened glass. The back surface protective member 18 (back sheet) is a protective member disposed on the back surface of the plurality of solar cells 40. The material of the back surface protective member 18 is, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), PVF, PVDF, etc. The color of the surface of the back surface protective member 18 on the solar cell side is the same color or a similar color as the color of the light-receiving surface 12 of the solar cell 40. The color of the surface of the back surface protective member 18 on the solar cell side is, for example, black or dark blue. In addition, L * a * b * The color difference ΔE between the color of the surface of the back surface protection member 18 on the solar cell side and the color of the light receiving surface of the solar cell 40 in the color space (color system) * is, for example, 0.0 or more and 10.0 or less, preferably 0.0 or more and 5.0 or less, and more preferably 0.0 or more and 2.0 or less. The color difference can be measured using a colorimeter, colorimeter, color difference meter, or the like. For example, the back surface protective member 18 may have a paint layer of the same color or a similar color as the light-receiving surface 12 of the solar cell 40 (external coloring). Furthermore, the back surface protective member 18 may be in the form of a sheet or a resin plate such as glass or polycarbonate. In this case, the back surface protective member 18 may be colored with a pigment of the same color or a similar color as the light-receiving surface 12 of the solar cell 40, or may be transparent and light-transmitting without being colored.

[0027] By making the color of both the light-receiving surface of the wiring cover 20 and the solar cell-side surface of the back-side protection member 18 the same color or a similar color as the light-receiving surface 12 of the solar cell 40, the color of the light-receiving surface of the solar cell module 50 appears to be a single color. This improves the design of the solar cell module 50. The sealant 22 is a material that seals the multiple solar cells 40 between the light-receiving surface protection member 17 and the back-side protection member 18. The sealant 22 is, for example, an ethylene vinyl acetate copolymer resin (EVA), a polyolefin-based resin, a polyvinyl butyral-based resin, or a silicone-based resin.

[0028] FIG. 7 is an explanatory diagram of a manufacturing method for a solar cell module 50. The manufacturing method for a solar cell module 50 includes the steps of forming a coating layer 5 on the periphery of the light-receiving surface 12 of each solar cell 40, inspecting the appearance of the solar cell 40 with the coating layer 5 formed thereon, and sealing multiple solar cells 40 between a light-receiving surface protective member 17 and a back surface protective member 18. First, as shown in FIG. 7( a), a solar cell is received, including a semiconductor substrate 2 having a first conductivity-type diffusion region 6 and a second conductivity-type diffusion region 7, a first electrode 3, a second electrode 4, and the like. Next, as shown in FIG. 7( b), paint is printed on the periphery of the light-receiving surface 12 of each solar cell 40 to form a coating layer 5. Next, the solar cell 40 is visually inspected, and solar cells 40 with visible chipping, stains, watermarks, color unevenness, etc. are removed from the production line. Because the solar cell 40 has the coating layer 5, most chipping, stains, watermarks, color unevenness, etc. are no longer visible. Therefore, the number of solar cells 40 removed from the production line during this visual inspection can be reduced, and visual yield can be improved.

[0029] Next, as shown in FIG. 7( c), multiple solar cell units 40 are connected in series using wiring 16. Wiring 16 is provided with wiring covers 20 that are the same color or similar to the color of the light-receiving surfaces 12 of the solar cell units 40. Next, as shown in FIG. 7( d), a back surface protection member 18, a sealant sheet, multiple solar cell units 40 with attached wiring 16 and wiring covers 20, a sealant sheet, and a light-receiving surface protection member 17 are stacked in this order, followed by lamination and other processes. Heat is applied to the sealant sheet to promote a cross-linking reaction of the sealant. Next, a terminal box is attached to the back side of the back surface protection member 18, and the wiring 16 and the terminal box are connected by wiring. In this manner, a solar cell module 50 is manufactured. After IV measurement, insulation testing, module appearance inspection, and other processes, the solar cell module 50 is shipped.

[0030] As described above, the solar cell 40 of the present disclosure has a coating layer 5 on the peripheral edge of the light-receiving surface 12 of the semiconductor substrate 2. Therefore, even if chipping, dirt, watermarks, or color unevenness occurs on the peripheral edge of the semiconductor substrate during the solar cell manufacturing process, including the step of forming an anti-reflection structure on the semiconductor substrate 2, the coating layer can cover the chipping, dirt, watermarks, color unevenness, etc., preventing the chipping, dirt, watermarks, color unevenness, etc. from becoming noticeable. Therefore, the solar cell 40 of the present disclosure can have high designability. Furthermore, the appearance yield of solar cells for installation in locations requiring high designability can be increased, thereby reducing manufacturing costs. Note that such appearance defects, such as chipping, dirt, watermarks, and color unevenness, occur more frequently on the peripheral edge of the semiconductor substrate (solar cell), particularly in linear portions. Therefore, forming a coating layer on at least the linear portions of the peripheral edge of the light-receiving surface of the solar cell improves the appearance yield of the solar cell. The designability can also be further improved by applying a coating layer to rounded corners on the peripheral edge of the light-receiving surface of the solar cell. Furthermore, the coating layer application process may be simplified by not applying a coating layer to the rounded corners of the periphery of the light-receiving surface of the solar cell.

[0031] Because the paint layer is formed by painting directly onto the solar cell, even if the solar cell is misaligned during lamination when manufacturing the solar cell module, the paint layer will not shift position. Therefore, a margin to prevent misalignment of the solar cell is not required, and the paint area can be minimized. Furthermore, because there is no gap between the solar cell and the paint layer, chipping or other defects in the semiconductor substrate are not visible even when viewed from an angle. The solar cell 40 of the present disclosure may be either a double-sided electrode type or a back-side electrode type. Since back-side electrode types, which have no electrodes on the light-receiving surface, have very noticeable appearance defects, the paint layer has a significant effect.

[0032] The manufacturing method for the solar cell module 50 of the present disclosure includes a step of inspecting the appearance of the solar cell 40 on which the paint layer 5 is formed before the step of sealing the solar cell 40 between the light-receiving surface protection member 17 and the back surface protection member 18, and removing solar cell 40 with poor appearance from the manufacturing line before forming the solar cell module 50. By inspecting the appearance of the solar cell 40 after forming the paint layer 5, the appearance yield of the solar cell can be increased. A step of inspecting the appearance of the solar cell may also be included before the step of forming the paint layer 5. In this case, solar cell 40 with poor appearance are selected, and the paint layer 5 is formed on the peripheral portion of the light-receiving surface 12 of the semiconductor substrate 2 of the solar cell. After the paint layer 5 is formed, the solar cell 40 is visually inspected again. By painting the solar cell with poor appearance, the number of solar cells to be painted can be reduced. The present disclosure is not limited to the above-described embodiment, and various modifications are possible within the spirit and scope of the invention.

[0033] 2: Semiconductor substrate 3: First electrode 4: Second electrode 5: Paint layer 6: First conductivity type diffusion region 7: Second conductivity type diffusion region 8: Semiconductor region 9: Anti-reflection film 10: Anti-reflection texture structure 12: Light-receiving surface 13: Back surface 14: Peripheral side surface 15: Bus bar 16: Wiring 17: Light-receiving surface side protective member 18: Back surface side protective member 20: Wiring cover 22: Sealant 23: Passivation film 25: First cell terminal 26: Second cell terminal 28: Chipping 40: Solar cell 50: Solar cell module

Claims

1. A solar cell comprising a coating layer applied to at least a linear portion of the periphery of the light-receiving surface of the solar cell, the solar cell having an anti-reflection film on its light-receiving surface, the coating layer being formed on the anti-reflection film, and the color of the coating layer being the same color or a similar color to the color of the light-receiving surface of the solar cell.

2. A solar cell comprising a coating layer applied to at least a linear portion of the periphery of the light-receiving surface of the solar cell, an electrode being disposed only on the back surface of the solar cell, and the color of the coating layer being the same color or a similar color to the color of the light-receiving surface of the solar cell.

3. The solar cell according to claim 1, wherein the anti-reflection film is a dielectric film.

4. The solar cell according to any one of claims 1 to 3, wherein the solar cell includes a silicon substrate, and the color of the coating layer is black or dark blue.

5. A solar cell according to claim 1 or 3, wherein an electrode is disposed only on the rear surface of the solar cell.

6. A solar cell according to any one of claims 1 to 3, wherein the coating layer is provided along the edge of the light-receiving surface of the solar cell and has a width of 3 mm or less.

7. A solar cell according to any one of claims 1 to 3, wherein the shape of the solar cell is a rectangle with at least two rounded corners, and the coating layer is disposed on the straight portions of the four sides of the periphery of the light-receiving surface of the solar cell, but is not disposed on the rounded corners of the periphery of the light-receiving surface of the solar cell.

8. A solar cell module comprising a plurality of solar cells according to any one of claims 1 to 3, a light-receiving surface protection member, and a back surface protection member, wherein the plurality of solar cells are arranged between the light-receiving surface protection member and the back surface protection member.

9. A solar cell module comprising a plurality of solar cells according to any one of claims 1 to 3, wiring, a light-receiving surface-side protective member, a back-side protective member, and a wiring cover covering at least a portion of the wiring, wherein the wiring connects two adjacent solar cells, the plurality of solar cells are arranged between the light-receiving surface-side protective member and the back-side protective member, the color of the surface of the back-side protective member facing the solar cells is the same color or a similar color as the color of the light-receiving surface of the solar cells, and the color of the surface of the light-receiving surface of the wiring cover is the same color or a similar color as the color of the light-receiving surface of the solar cells.

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