Solar cells and solar modules

Abstract

To provide a solar cell that has high designability.SOLUTION: A solar cell comprises a coating layer formed at least at a linear part of a peripheral edge part of a light reception surface of the solar cell, and has an antireflection film on its light reception surface, wherein the coating layer is formed on the antireflection film, and the color of the coating layer is the same as or similar to the color of the light reception surface of the solar cell.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to solar cells and solar modules. [Background technology]

[0002] In recent years, solar cells have been used in a variety of locations beyond just residential roofs and solar power plants. For example, solar modules installed on vehicle roofs are more visible to users than those installed on residential roofs or power plants, requiring a much higher level of design aesthetics than before. To improve the aesthetic design of solar cell modules, there are known solar cell modules in which a black pattern is provided on the light-receiving protective member so as to overlap the gaps between solar cells, making the gaps between the solar cells invisible (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] WO2020 / 121693A1 [Overview of the project] [Problems that the invention aims to solve]

[0004] Solar cells typically have an anti-reflective coating and / or anti-reflective texture structure on their light-receiving surface, resulting in a dark blue or black color on the surface. If there is chipping (a chip at the corner between the light-receiving surface and the peripheral surface) on the periphery of the solar cell, the anti-reflective coating and / or anti-reflective texture structure is lost only in the chipped area, exposing the original semiconductor surface and causing it to reflect light. While chipping is not noticeable in solar modules installed on residential roofs or in solar power plants because they are installed in high places or areas with little foot traffic, it is very noticeable in solar modules mounted on vehicles because the modules are viewed at close range. In solar modules mounted on vehicles, even chipping as small as 0.1mm to 1.0mm can be detected. Therefore, the aesthetic requirements for solar modules placed in close proximity to users, such as those mounted on vehicles, are high, and the solar cells that make up these modules require a high level of design aesthetics. Furthermore, dirt, watermarks, and discoloration on the light-receiving surface of solar cells, similar to chipping, detract from the aesthetic appeal of the solar cells. Solar cells with poor aesthetic appeal are removed from the production line during visual inspection when appearance requirements are high, thus reducing the yield based on appearance. Incidentally, defects that reduce the aesthetic appeal of solar cells include chipping, dirt, watermarks, and color unevenness, as mentioned above, and it has been found that all of these tend to occur more frequently at the periphery of the solar cell. For example, chipping is likely to occur when semiconductor substrates are placed in cassettes or deposition trays during the manufacturing process of solar cells, or when the edges of the semiconductor substrate or solar cell being transported come into contact with guide pins. Small chips (e.g., chips of 3 mm or less) occur particularly frequently. Also, dirt (such as oil) may adhere to the periphery of the semiconductor substrate or solar cell when the semiconductor substrate is placed in cassettes or deposition trays, or when the edges of the semiconductor substrate or solar cell being transported come into contact with guide pins. Furthermore, during the drying process after wet processing of the semiconductor substrate, watermarks may occur at the periphery of the semiconductor substrate due to water droplets remaining between the cassette guide and the semiconductor substrate. In addition, when depositing an anti-reflective film on the surface of a semiconductor substrate, uneven film deposition is likely to occur at the periphery of the semiconductor substrate, and color unevenness may occur due to differences in the thickness of the anti-reflective film. One possible method for using solar cells with defects that reduce their aesthetic appeal at the periphery is to apply a black pattern to the light-receiving protective member so that it overlaps the edge of the solar cell, as described in Patent Document 1. However, it is necessary to consider tolerances such as the positional accuracy when placing the solar cell on the light-receiving protective member, the amount of cell displacement during lamination, and the appearance from an oblique angle, which necessitates increasing the area of ​​the black pattern by a margin. As a result, there is a problem that the amount of light received by the solar cell decreases, leading to a decrease in the amount of power generated by the solar cell. This invention has been made in view of these circumstances and provides a solar cell with high design quality. [Means for solving the problem]

[0005] The present invention provides a solar cell comprising a coating layer applied to at least a straight portion of the peripheral edge of the light-receiving surface of the solar cell, wherein the solar cell has an anti-reflective film on its light-receiving surface, the coating layer is formed on the anti-reflective film, and the color of the coating layer is the same as or a similar color to the color of the light-receiving surface of the solar cell. [Effects of the Invention]

[0006] According to the present invention, the aesthetic design of solar cells is improved. [Brief explanation of the drawing]

[0007] [Figure 1] (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 the same solar cell. [Figure 2] (a) and (b) are schematic plan views of a solar cell according to one embodiment of the present invention. [Figure 3] (a) is a schematic cross-sectional view of a solar cell along the dashed line AA in Figure 1, and (b) is a schematic cross-sectional view of a solar cell comprising a semiconductor substrate with chipping at its edges. [Figure 4] This is an explanatory diagram of chipping. [Figure 5] This is a schematic plan view of a solar cell module according to one embodiment of the present invention. [Figure 6] Figure 5 is a schematic cross-sectional view of the solar cell module along the dashed line BB. [Figure 7] (a) to (d) are explanatory diagrams for a method of manufacturing a solar cell module according to one embodiment of the present invention. [Modes for carrying out the invention]

[0008] The solar cell of the present invention is characterized by comprising a coating layer applied to at least a straight portion of the peripheral edge of the light-receiving surface of the solar cell, wherein the color of the coating layer is the same as or a similar color to the color of the light-receiving surface of the solar cell. Furthermore, the solar cell of the present invention comprises a coating layer applied to at least a straight portion of the peripheral edge of the light-receiving surface of the solar cell, the solar cell has an anti-reflective film on its light-receiving surface, the coating layer is formed on the anti-reflective film, and the color of the coating layer is the same as or a similar color to the color of the light-receiving surface of the solar cell. Furthermore, the solar cell of the present invention is characterized by having a coating layer applied to at least a straight portion of the peripheral edge of the light-receiving surface of the solar cell, electrodes arranged only on the back surface of the solar cell, and the color of the coating layer being the same color as or a similar color to the color of the light-receiving surface of the solar cell.

[0009] The solar cell includes a silicon substrate, and the color of the coating layer is preferably black or dark blue. It is preferable that electrodes are placed only on the back surface of the solar cell (back-contact type solar cell). In a back-contact type solar cell, where electrodes are not placed on the light-receiving surface, the design of the solar cell can be improved as there are no electrodes on the light-receiving surface. Preferably, the width of the coating layer provided along the edge of the light-receiving surface of the solar cell is 3 mm or less. This enhances the aesthetic appeal of the solar cell and suppresses a reduction in the light-receiving area. When the shape of the solar cell in a plan view is a rectangle with at least two rounded corners, the coating layer is arranged on the straight parts of the four sides of the periphery of the light-receiving surface of the solar cell, and does not need to be arranged on the rounded corners of the periphery of the light-receiving surface of the solar cell. This enhances the aesthetic appeal of the solar cell and allows for easy formation of 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 side protective member, and a back-side protective member. The solar cell module of the present invention has a high aesthetic appeal because it is composed of solar cells with a high aesthetic appeal. Furthermore, the present invention provides a solar cell module including a plurality of solar cells of the present invention, wiring, a light-receiving surface side protective member, a back surface side protective member, and a wiring cover covering at least a part of the wiring. The wiring connects two adjacent solar cells, and the plurality of solar cells are arranged between the light-receiving surface side protective member and the back surface side protective member. The color of the surface of the back surface side protective member on the solar cell side is the same color or a similar color to the color of the light-receiving surface of the solar cell, and the color of the surface of the wiring cover on the light-receiving surface side is the same color or a similar color to the color of the light-receiving surface of the solar cell. The solar cell module of the present invention has high design quality because its light-receiving surface appears to be of a single color.

[0011] Hereinafter, the present invention will be described in more detail with reference to a plurality of embodiments. The configurations shown in the drawings and the following description are illustrative, 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 the solar cell of this embodiment, and FIG. 1(b) is a schematic back view of this solar cell. FIGS. 2(a) and 2(b) are schematic plan views of the solar cells of modification examples of this embodiment, respectively. FIG. 3(a) is a schematic cross-sectional view of the solar cell taken along the broken 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 chip at an end. The solar cell 40 of 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 coated on at least a linear portion of the peripheral edge 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. The solar cell 40 has at least one of an antireflection film 9 and an antireflection texture structure 10 on the light-receiving surface 12. The antireflection film 9 is a film laminated on the light-receiving surface of the semiconductor substrate 2. The antireflection texture structure 10 is an uneven structure formed on the light-receiving surface of the semiconductor substrate 2. 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. The colors of the light-receiving surface 12, the coating layer 5, etc. can be digitized using a colorimeter.

[0013] The semiconductor substrate 2 is a semiconductor substrate, for example, a single crystal silicon substrate, a polycrystalline silicon substrate, a CIS semiconductor substrate, a CIGS semiconductor substrate, a III-V compound semiconductor substrate, etc. The solar cell 40 includes the semiconductor substrate 2 and has a pn junction that can generate a photovoltaic power. The semiconductor substrate 2 included in the solar cell 40 is not particularly limited. The semiconductor substrate 2 of this embodiment, for example, 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 or second conductivity type region may be a base region of the semiconductor substrate (for example, when a p-type semiconductor substrate is used as the base material, the p-type semiconductor region originally possessed by this substrate), or may be a deposited film deposited on the substrate serving as the base material. Also, the semiconductor substrate may have both a diffusion region and a deposited film. One of the first conductivity type and the second conductivity type is n-type (majority carriers are electrons), and the other is p-type (majority carriers are holes). A pn junction is formed in the semiconductor substrate 2 by these regions. When 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 where 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 where an n-type dopant such as phosphorus (P) is diffused.

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

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

[0016] The first electrode 3 and the second electrode 4 are electrodes for extracting the photovoltaic power generated in the semiconductor substrate 2 to the outside. 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). Furthermore, as shown in Figures 1-3, both the first electrode 3 and the second electrode 4 may be provided on the back surface of the semiconductor substrate 2 (back-contact type solar cell). The back-contact type solar cell has high design aesthetics because it does not have electrodes on the light-receiving surface 12. The shape of the first electrode 3 is linear, and the shape of the second electrode 4 is linear. Also, the linear first electrode 3 and the linear second electrode 4 are arranged alternately on the back surface of the semiconductor substrate 2. The linear first electrode 3 is connected to the first cell terminal 25 provided on the back surface of the semiconductor substrate 2, and the linear second electrode 4 is connected to the second cell terminal 26 provided on the back surface of the semiconductor substrate 2. The 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 type solar cell may have a structure in which linear first conductivity type diffusion regions 6, in which a first conductivity type dopant is linearly diffused on the back 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, in which a second conductivity type dopant is diffused on the back side of the semiconductor region 8, are alternately arranged. The linear first electrode 3 can be connected to a linear first conductivity type diffusion region 6 via a linear opening provided in the passivation film 23 on the back surface of the semiconductor substrate 2. Similarly, the linear second electrode 4 can be connected to a linear second conductivity type diffusion region 7 via 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 of paint applied to the light-receiving surface of the solar cell 40. The coating layer 5 may contain pigments and resins. Preferably, the pigments included in the coating layer 5 are light-resistant pigments. This helps to suppress discoloration of the coating layer 5. The paint used to form the coating layer 5 includes, for example, pigments, resins, and solvents. The method of applying the paint to the light-receiving surface of the solar cell 40 to form the coating layer 5 is not particularly limited, but examples include inkjet printing, spray coating, transfer printing, and screen printing. The coating layer 5 can be provided in contact with the anti-reflective film 9.

[0019] The coating layer 5 is a layer applied to at least a straight portion of the peripheral edge of the light-receiving surface 12 of the solar cell 40. In this embodiment, the coating layer 5 is provided on an anti-reflective film 9 formed on the semiconductor substrate 2. By providing such a coating layer 5, even if there is chipping 28 (a chip at the corner between the light-receiving surface 12 and the peripheral surface 14, see Figures 4(a) and 4(b)), dirt, watermarks, or color unevenness on the peripheral edge of the light-receiving surface 12 of the solar cell 40, these will be hidden by the coating layer 5, thus preventing a decrease in the aesthetic appearance of the solar cell 40. Furthermore, even if there is chipping 28, dirt, watermarks, or color unevenness on the peripheral edge of the light-receiving surface 12 of the solar cell 40, these will be hidden by the coating layer 5, so they will not result in an appearance defect of the solar cell 40, thereby improving the appearance yield. The coating layer 5 may be provided over the entire periphery of the light-receiving surface 12, as shown in Figure 1(a).

[0020] As shown in Figures 2(a) and 2(b), the coating layer 5 is applied to the straight portion of the peripheral edge of the light-receiving surface 12, and does not necessarily have to be applied to the rounded corner portion of the peripheral edge of the light-receiving surface 12. Chipping, dirt, watermarks, and color unevenness tend to occur on the straight portion of the peripheral edge of the light-receiving surface 12 and less likely to occur on the rounded corner portion (for example, because the straight portion of the semiconductor substrate 2 comes into contact with guide pins during the manufacturing process). Therefore, by applying the coating layer 5 to the straight portion of the peripheral edge of the light-receiving surface 12, it is possible to prevent a decrease in the aesthetic appearance of the solar cell 40 and improve the yield of appearance. In addition, it is possible to suppress a decrease in the amount of light incident on the solar cell 40. Furthermore, since it is only necessary to paint the straight portion of the peripheral edge of the light-receiving surface 12, it can be easily painted.

[0021] The color of the coating layer 5 is the same as 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 electrodes if electrodes are provided) appears to be a single color, improving the aesthetic appeal of the solar cell 40 and improving the yield of appearance. The light-receiving surface 12 of a solar cell 40, which includes a semiconductor substrate 2 (silicon substrate) and has an anti-reflective film 9 or an anti-reflective texture structure 10 on its light-receiving surface, is usually black to dark blue. Therefore, the color of the coating layer 5 is black to dark blue. Alternatively, the color of the coating layer 5 may be a single color. L * a * b * The color difference ΔE between the color of the painted layer 5 in the color space (color system) and the color of the light-receiving surface 12 of the solar cell 40. * For example, the value is between 0.0 and 10.0, preferably between 0.0 and 5.0, and more preferably between 0.0 and 2.0. The color difference can be measured using a colorimeter, colorimeter, color difference meter, etc.

[0022] The coating layer 5 is linear and is applied to the linear region between the edge of the light-receiving surface 12 of the solar cell 40 and a line along the edge 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 even more preferably 0.5 mm or less. This makes it possible to hide chipping, dirt, watermarks, color unevenness, etc., and also suppresses a decrease in the amount of light incident on the semiconductor substrate 2, thereby suppressing a decrease in power generation. In addition, it can hide chipping of 3 mm or less, which occurs frequently. The thickness of the coating layer 5 is, for example, 0.5 μm or more and 10 μm or less.

[0023] Second Embodiment Figure 5 is a schematic plan view of the solar cell module of this embodiment, and Figure 6 is a schematic cross-sectional view of the solar cell module along the dashed line BB in Figure 5. The solar cell module 50 comprises a plurality of solar cells 40 of the first embodiment, wiring 16, a light-receiving surface side protective member 17, a back side protective 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 are therefore omitted 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 Figures 5 and 6 has six solar cell strings, each consisting of five solar cells 40 connected in series, with each solar cell string connected in series. All solar cells 40 included in the solar cell module 50 can have substantially the same shape. In addition, the coating layer 5 of all solar cells 40 included in the solar cell module 50 can have substantially the same pattern. This allows for a unified appearance of the solar cells 40, improving the aesthetic design of the solar cell module 50. Furthermore, the light-receiving area of ​​the cells can be standardized, suppressing variations in the output current values ​​of the solar cells 40.

[0024] In a solar cell string, the first cell terminal 25 of one of two adjacent solar cells 40 is connected to the second cell terminal 26 of the other solar cell 40 by a wiring 16. Furthermore, the cell terminals at both ends of the solar cell string are connected to different busbars 15 by wiring 16. The busbars 15 are connected to terminal boxes located on the back surfaces of adjacent solar cell strings and / or solar modules 50.

[0025] Of the wiring 16, at least the inter-cell wiring is covered by the wiring cover 20 on at least the light-receiving side. In addition, the busbar 15 may also be covered by the wiring cover 20 on at least the light-receiving side. The wiring cover 20 may be sheet-shaped or may be a coating layer of the wiring 16. In the solar cell module 50 shown in FIGS. 5 and 6, the wiring cover 20 is a coating layer of 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 surface side of the wiring cover 20 and the color of the light-receiving surface of the solar cell 40 in a 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 by a colorimeter, a color analyzer, a color difference meter, or the like.

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

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

[0028] Figure 7 is an explanatory diagram of the manufacturing method of the solar cell module 50. The manufacturing method of the solar cell module 50 includes the steps of forming a coating layer 5 on the peripheral edge of the light-receiving surface 12 of the solar cell 40, inspecting the appearance of the solar cell 40 on which the coating layer 5 has been formed, and sealing a plurality of solar cells 40 between a light-receiving surface side protective member 17 and a back side protective member 18. First, as shown in Figure 7(a), a solar cell 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, etc., is received. Next, as shown in Figure 7(b), paint is printed on the peripheral edge of the light-receiving surface 12 of the solar cell 40 to form a coating layer 5. Next, the appearance of the solar cell 40 is inspected, and solar cell 40 showing chipping, dirt, watermarks, color unevenness, etc., is removed from the manufacturing line. Because the solar cell 40 has a coating layer 5, most chipping, dirt, 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, thereby improving the visual yield.

[0029] Next, as shown in Figure 7(c), multiple solar cells 40 are connected in series using wiring 16. The wiring 16 is fitted with a wiring cover 20 that is the same color as or a similar color to the light-receiving surface 12 of the solar cell 40. Next, as shown in Figure 7(d), the back-side protective member 18, the sealing sheet, the multiple solar cells 40 with wiring 16 and wiring cover 20 attached, the sealing sheet, and the light-receiving side protective member 17 are stacked in this order, and lamination is performed. In addition, heat is applied to the sealing sheet to promote the cross-linking reaction of the sealing material. Next, a terminal box is attached to the back side of the back-side protective member 18, and the wiring 16 and the terminal box are connected by wiring. In this way, the solar cell module 50 is manufactured. Afterward, IV measurement, insulation testing, and module appearance inspection are performed before the solar cell modules 50 are shipped.

[0030] As described above, the solar cell 40 of the present invention 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 occur on the peripheral edge of the semiconductor substrate during the solar cell manufacturing process, which includes the step of forming an anti-reflective structure on the semiconductor substrate 2, the coating layer can cover the chipping, dirt, watermarks, and color unevenness, preventing them from being noticeable. Accordingly, the solar cell 40 of the present invention can have high aesthetic appeal. Furthermore, it is possible to increase the yield of solar cells with good appearance for installation in locations where high aesthetic appeal is required, thereby reducing manufacturing costs. It should be noted that such cosmetic defects such as chipping, dirt, watermarks, and color unevenness occur frequently on the peripheral edge of the semiconductor substrate (solar cell), especially in straight sections. Therefore, by forming a coating layer on at least the straight sections of the peripheral edge of the light-receiving surface of the solar cell, the yield of good appearance of the solar cell can be improved. The aesthetic appeal can be further improved by also placing a coating layer on the rounded corners of the peripheral edge of the light-receiving surface of the solar cell. Furthermore, the process of applying the coating layer can be simplified by not applying the coating layer to the rounded corners of the periphery of the light-receiving surface of the solar cell.

[0031] Since the coating layer is formed by directly painting the solar cells, the position of the coating layer will not shift even if the solar cells shift during the lamination process when manufacturing the solar cell module. Therefore, a margin to compensate for solar cell misalignment is unnecessary, and the coating area can be minimized. In addition, because there is no gap between the solar cells and the coating layer, chipped areas of the semiconductor substrate are not visible even when viewed from an angle. The solar cell 40 of the present invention may be of the double-sided electrode type or the back-side electrode type. In the back-side electrode type, where there are no electrodes on the light-receiving surface, cosmetic defects are very noticeable, so the effect of the coating layer is significant.

[0032] The manufacturing method for the solar cell module 50 of the present invention includes a step of inspecting the appearance of the solar cell 40 on which the coating layer 5 has been formed, before the step of sealing a plurality of solar cell 40 between the light-receiving side protective member 17 and the back side protective member 18, thereby removing solar cell 40 with appearance defects from the manufacturing line before forming the solar cell module 50. By performing the appearance inspection of the solar cell 40 after forming the coating layer 5, the yield of solar cell appearance can be increased. Furthermore, a step of visual inspection of the solar cells may be included before the step of forming the coating layer 5. In this case, solar cells with visual defects are extracted, and the coating layer 5 is formed on the peripheral edge of the light-receiving surface 12 of the semiconductor substrate 2 of the solar cell. After the formation of the coating layer 5, the visual inspection of the solar cells 40 is performed again. By coating the solar cells with visual defects, the number of solar cells to be coated can be reduced. The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the invention. [Explanation of symbols]

[0033] 2: Semiconductor substrate 3: First electrode 4: Second electrode 5: Coating layer 6: First conductivity type diffusion region 7: Second conductivity type diffusion region 8: Semiconductor region 9: Anti-reflective film 10: Anti-reflective texture structure 12: Light-receiving surface 13: Back surface 14: Peripheral side 15: Busbar 16: Wiring 17: Protective material on the light-receiving surface side 18: Protective material on the back side 20: Wiring cover 22: Encapsulation material 23: Passivation film 25: First cell terminal 26: Second cell terminal 28: Chipping 40: Solar cell 50: Solar cell module

Claims

1. The solar cell comprises a pigment layer provided on at least a straight portion of the peripheral edge of the light-receiving surface, The aforementioned solar cell has an anti-reflective coating on its light-receiving surface, The shape of the solar cell is a rectangle with four straight sides. The aforementioned quadrilateral is a rounded rectangle, a rectangle, or a shape obtained by dividing a rounded rectangle. The pigment layer is formed on the anti-reflective film and is provided linearly along each of the four sides of the solar cell. The linear pigment layer is provided in a linear region between the edge of the light-receiving surface and the line along the edge, L * a * b * The color difference ΔE between the color of the pigment layer in the color space and the color of the light-receiving surface. * A solar cell characterized by having a value between 0.0 and 10.

0.

2. The solar cell comprises a pigment layer provided on at least a straight portion of the peripheral edge of the light-receiving surface, The shape of the solar cell is a rectangle with four straight sides. The aforementioned quadrilateral is a rounded rectangle, a rectangle, or a shape obtained by dividing a rounded rectangle. The electrodes are arranged only on the back surface of the aforementioned solar cell. The pigment layer is provided linearly along each of the four sides of the solar cell. The linear pigment layer is provided in a linear region between the edge of the light-receiving surface and the line along the edge, L * a * b * The color difference ΔE between the color of the pigment layer in the color space and the color of the light-receiving surface. * A solar cell characterized by having a value between 0.0 and 10.

0.

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

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

5. The solar cell according to claim 1 or 3, wherein electrodes are arranged only on the back surface of the solar cell.

6. The pigment layer is provided along the edge of the light-receiving surface of the solar cell, The solar cell according to any one of claims 1 to 3, wherein the width of the pigment layer is the distance from the edge of the light-receiving surface and is within 3 mm.

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

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

9. 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 that covers at least a portion of the wiring, The aforementioned wiring connects two adjacent solar cells. Multiple solar cells are arranged between the light-receiving side protective member and the back side protective member. L * a * b * The color difference ΔE between the color of the surface on the solar cell side of the back surface side protection member in the color space and the color of the light receiving surface of the solar cell * is 0.0 or more and 10.0 or less, L * a * b * The color difference ΔE between the color of the light-receiving surface of the wiring cover and the color of the light-receiving surface of the solar cell in the color space. * This refers to a solar cell module with a value between 0.0 and 10.0.

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