Solar cell and method for producing same

Abstract

[Problem] To prevent damage to a photoelectric conversion unit and the like during dicing in a method for producing a solar cell that uses a film-like substrate. [Solution] A method for producing a solar cell (100), said method comprising: a first step for forming a photoelectric conversion unit (20) on a surface (11) of a film-like substrate (10); a second step for forming an insulating resin (30) on the surface (11) of the substrate (10) so as to cover an outer peripheral part (21) of the photoelectric conversion unit (20); a third step for forming, on the surface (11) of the substrate (10), a cushioning layer (40) which has a Young's modulus lower than that of the insulating resin (30), so as to cover an outer peripheral part (31) of the insulating resin (30); and a fourth step for dicing the substrate (10) by cutting the substrate (10) along the cushioning layer (40).

Description

Solar cell and its manufacturing method

[0001] The present disclosure relates to a solar cell and a manufacturing method thereof, and more particularly to a solar cell using a film-like substrate and a manufacturing method thereof.

[0002] Patent Document 1 discloses a solar cell using a film-like substrate. When manufacturing this type of solar cell, it is common to simultaneously form a plurality of solar cells on a substrate, and then cut the substrate to separate the solar cells into individual solar cells.

[0003] Japanese Patent Application Laid-Open No. 2018-083873

[0004] However, when cutting the substrate, stress is applied by the cutting blade, which may damage the photoelectric conversion section and the like.

[0005] This disclosure describes a solar cell using a film-like substrate and a manufacturing method thereof, which prevents damage to the photoelectric conversion section and the like during singulation and improves the reliability of the solar cell.

[0006] A solar cell according to one aspect of the present disclosure comprises a film-like substrate, a photoelectric conversion unit provided on the substrate, an insulating resin provided on the substrate and covering the outer edge of the photoelectric conversion unit, and a buffer layer provided on the substrate, covering the outer edge of the insulating resin, and having a lower Young's modulus than the insulating resin, wherein the outer edge of the buffer layer is exposed.

[0007] A method for manufacturing a solar cell according to one aspect of the present disclosure includes a first step of forming a photoelectric conversion section on the surface of a film-like substrate, a second step of forming an insulating resin on the substrate so as to cover the outer edge of the photoelectric conversion section, a third step of forming a buffer layer on the substrate having a lower Young's modulus than the insulating resin so as to cover the outer edge of the insulating resin, and a fourth step of cutting the substrate along the buffer layer to individualize the substrate.

[0008] According to the present disclosure, in a solar cell using a film-like substrate and a manufacturing method thereof, a technique is provided that prevents damage to the photoelectric conversion section and the like during singulation and improves the reliability of the solar cell.

[0009] FIG. 1 is a schematic plan view showing the appearance of a solar cell 100 according to one embodiment of the technology disclosed herein. FIG. 2 is a schematic cross-sectional view taken along line A-A in FIG. 1 . FIG. 3 is a schematic plan view illustrating a method for manufacturing the solar cell 100. FIG. 4 is a schematic cross-sectional view illustrating a method for manufacturing the solar cell 100, showing a cross-section taken along line B-B in FIG. 3 . FIG. 5 is a schematic cross-sectional view illustrating a method for manufacturing the solar cell 100, showing a cross-section taken along line B-B in FIG. 3 . FIG. 6 is a schematic cross-sectional view illustrating a manufacturing method of the solar cell 100 according to a first modified example, showing a cross-section taken along line B-B in FIG. 3 . FIG. 7 is a schematic cross-sectional view illustrating the structure of the solar cell 100 obtained by the manufacturing method according to the first modified example, showing a cross-section taken along line A-A in FIG. 1 . FIG. 8 is a schematic cross-sectional view illustrating a manufacturing method of the solar cell 100 according to a second modified example, showing a cross-section taken along line B-B in FIG. 3 . FIG. 9 is a schematic cross-sectional view illustrating the structure of the solar cell 100 obtained by the manufacturing method according to the second modified example, showing a cross-section taken along line A-A in FIG. 1 .

[0010] Hereinafter, embodiments of the technology according to the present disclosure will be described in detail with reference to the accompanying drawings.

[0011] Fig. 1 is a schematic plan view showing the appearance of a solar cell 100 according to an embodiment of the technology disclosed herein, and Fig. 2 is a schematic cross-sectional view taken along line AA shown in Fig. 1.

[0012] As shown in Figures 1 and 2, the solar cell 100 according to this embodiment comprises a film-like substrate 10, a photoelectric conversion unit 20 provided on the surface 11 of the substrate 10, an insulating resin 30 provided on the surface 11 of the substrate 10 and covering the outer edge 21 of the photoelectric conversion unit 20 and an area of ​​the light-receiving surface 22 near the outer edge 21, a buffer layer 40 provided on the surface 11 of the substrate 10 and covering the outer edge 31 of the insulating resin 30, and a sealing resin 50 provided on the surface 11 of the substrate 10 and covering the photoelectric conversion unit 20, the insulating resin 30, and the buffer layer 40.

[0013] The substrate 10 is a flexible film-like member made of an insulating material such as polyethylene naphthalate, and functions as a support for the photoelectric conversion section 20 , the insulating resin 30 , the buffer layer 40 , and the sealing resin 50 .

[0014] The photoelectric conversion section 20 is a semiconductor element that converts incident light incident on the light receiving surface 22 into electric power, and is formed on almost the entire surface 11 of the substrate 10 except for the outer periphery.

[0015] The insulating resin 30 is a protective member for protecting the outer edge 21 of the photoelectric conversion unit 20, and is made of a high-strength material such as a thermosetting resin material. As an example, the insulating resin 30 can be made of a polyimide resin. The insulating resin 30 may contain a filler for adjusting its characteristics.

[0016] The buffer layer 40 is made of an insulating material with a lower Young's modulus than the insulating resin 30. As an example, the buffer layer 40 can be made of a polyethylene-based resin. The Young's modulus of polyethylene-based resin is less than 1 GPa, which is sufficiently lower than the Young's modulus of polyimide-based resin, which is approximately 4 GPa. The Young's modulus of the buffer layer 40 is preferably 1 GPa or less, and more preferably in the range of 0.8 GPa to 1 GPa. The buffer layer 40 is not in contact with the photoelectric conversion section 20. The buffer layer 40 may contain a filler to adjust its characteristics.

[0017] The sealing resin 50 serves to protect the photoelectric conversion unit 20 by covering the region of the light-receiving surface 22 of the photoelectric conversion unit 20 that is surrounded by the insulating resin 30. The sealing resin 50 may be made of, for example, a transparent thermoplastic resin material. The material of the sealing resin 50 may be the same as the material of the insulating resin 30. The sealing resin 50 may not contain a filler that hinders light transmission. In the example shown in FIG. 2 , the sealing resin 50 covers not only the region of the light-receiving surface 22 of the photoelectric conversion unit 20 that is surrounded by the insulating resin 30, but also the inner edge 32 of the insulating resin 30, the upper surface 33 of the insulating resin 30 that is parallel to the surface 11 of the substrate 10, and the upper surface 42 of the buffer layer 40 that is parallel to the surface 11 of the substrate 10. Note that FIG. 1 shows the state seen through the transparent sealing resin 50. The insulating resin 30 and the buffer layer 40 do not need to be transparent and may be colored.

[0018] 2 , the outer edge 41 of the buffer layer 40 is exposed, and the outer edge 12 of the substrate 10, the outer edge 41 of the buffer layer 40, and the outer edge 51 of the sealing resin 50 form the same plane. In this way, because the outer edge 41 of the buffer layer 40, which has a low Young's modulus, is exposed on the side surface of the solar cell 100, an external force applied to the side surface of the solar cell 100 is less likely to be transmitted to the photoelectric conversion unit 20, thereby improving the reliability of the solar cell 100.

[0019] 3 to 5 are schematic diagrams illustrating the method for manufacturing the solar cell 100 according to this embodiment. 4 and 5 show cross sections taken along line BB in FIG.

[0020] First, as shown in Fig. 3, a plurality of photoelectric conversion sections 20, a plurality of insulating resins 30, a buffer layer 40, and a sealing resin 50 are formed in this order on the surface 11 of the film-like substrate 10. The transparent sealing resin 50 is not shown in Fig. 3. In the example shown in Fig. 3, four photoelectric conversion sections 20 are formed on the surface 11 of the substrate 10. There is no particular limitation on the number of photoelectric conversion sections 20 formed on the surface 11 of the substrate 10.

[0021] As shown in FIG. 4 , when forming the insulating resin 30, a plurality of insulating resins 30 are formed on the surface 11 of the substrate 10 so as to cover the outer edge 21 of the photoelectric conversion unit 20 and the region of the light-receiving surface 22 near the outer edge 21. When forming the buffer layer 40, the buffer layer 40 is formed on the surface 11 of the substrate 10 so as to cover the outer edge 31 of the insulating resin 30. The insulating resin 30 and the buffer layer 40 can be formed by, for example, screen printing or inkjet printing. The sealing resin 50 may be formed over almost the entire surface. In other words, when forming the sealing resin 50, the region of the photoelectric conversion unit 20 surrounded by the insulating resin 30, the insulating resin 30, and the buffer layer 40 are covered by the sealing resin 50.

[0022] 4, the buffer layer 40 is embedded between two adjacent solar cells 100 before singulation. In other words, the buffer layer 40 is embedded between the outer edge 31 of the insulating resin 30 included in one solar cell 100 and the outer edge 31 of the insulating resin 30 included in the other solar cell 100.

[0023] Next, the substrate 10 is cut along dashed lines C shown in FIG. 3 to separate the solar cells 100. The dashed lines C are located on the buffer layer 40, and therefore, the substrate 10 is cut along the buffer layer 40. Cutting of the substrate 10 can be performed, for example, by pressing a pinnacle blade 60 against the substrate 10, as shown in FIG. 5 . When the pinnacle blade 60 is pressed against the substrate 10, not only is a force F1 acting in the direction of the pinnacle blade 60, but also a force F2 acting in the left-right direction due to the thickness of the pinnacle blade 60, acts on the pressed region. However, in this embodiment, most of these forces F1 and F2 are absorbed by the buffer layer 40, which has a low Young's modulus, significantly reducing the forces applied to the photoelectric conversion unit 20 and the insulating resin 30 during singulation. This makes it possible to prevent damage to the photoelectric conversion unit 20 and the insulating resin 30 during singulation.

[0024] 5, the upper surface 42 of the buffer layer 40 is covered with the sealing resin 50, and therefore the sealing resin 50 covering the buffer layer 40 is also cut during singulation. However, if the thickness of the sealing resin 50 located on the upper surface 42 of the buffer layer 40 is sufficiently thin, the sealing resin 50 will not be damaged during singulation.

[0025] Alternatively, as in the first modified example shown in FIG. 6 , if the upper surface 42 of the buffer layer 40 is exposed and not covered with the sealing resin 50, the substrate 10 can be cut along the buffer layer 40 without cutting the sealing resin 50 during singulation. This prevents force from being applied to the sealing resin 50 during singulation. In this case, the sealing resin 50 can be formed while avoiding the buffer layer 40. In the solar cell 100 obtained by this method, as shown in FIG. 7 , the outer edge 51 of the sealing resin 50 is offset inward from the outer edge 41 of the buffer layer 40. This makes it difficult for external forces applied to the side surfaces of the solar cell 100 to be transmitted to the sealing resin 50, thereby further improving the reliability of the solar cell 100.

[0026] Furthermore, as in the second modified example shown in FIG. 8 , not only may the upper surface 42 of the buffer layer 40 be exposed without being covered by the sealing resin 50, but also a portion of the upper surface 33 of the insulating resin 30 may be covered by the buffer layer 40. That is, a portion of the upper surface 33 of the insulating resin 30 may be covered by the sealing resin 50, and another portion of the upper surface 33 of the insulating resin 30 may be covered by the buffer layer 40. In this case, too, no force is applied to the sealing resin 50 during singulation. In the solar cell 100 obtained by this method, as shown in FIG. 9 , the outer edge 51 of the sealing resin 50 is covered by the buffer layer 40 without being exposed. This makes it difficult for external forces applied to the side surfaces of the solar cell 100 to be transmitted by the sealing resin 50, further improving the reliability of the solar cell 100.

[0027] As described above, in the solar cell 100 according to this embodiment, the substrate 10 is cut along the buffer layer 40 having a low Young's modulus during singulation, which makes it possible to prevent breakage during singulation. Moreover, after singulation, the buffer layer 40 having a low Young's modulus is exposed on the side surface of the solar cell 100, which makes it difficult for external forces applied to the side surface of the solar cell 100 to be transmitted to the photoelectric conversion unit 20, thereby improving the reliability of the solar cell 100.

[0028] The above describes embodiments of the technology according to the present disclosure, but the technology according to the present disclosure is not limited to the above embodiments, and various modifications are possible within the scope of the gist of the technology, and it goes without saying that these modifications are also included within the scope of the technology according to the present disclosure.

[0029] The technology according to the present disclosure includes, but is not limited to, the following configuration examples.

[0030] A solar cell according to one aspect of the present disclosure includes a film-like substrate, a photoelectric conversion unit provided on the substrate, an insulating resin provided on the substrate and covering an outer edge of the photoelectric conversion unit, and a buffer layer provided on the substrate and covering the outer edge of the insulating resin, the buffer layer having a lower Young's modulus than the insulating resin, the outer edge of which is exposed. In this way, the buffer layer exposed on the side surface of the solar cell makes it difficult for external forces to be transmitted to the photoelectric conversion unit, thereby improving the reliability of the solar cell.

[0031] In the solar cell described above, the insulating resin may be made of a thermosetting resin material, and the buffer layer may be made of a thermoplastic resin material, which allows the photoelectric conversion section to be sufficiently protected by the insulating resin made of a thermosetting resin material, while the buffer layer made of a thermoplastic resin material allows high flexibility to be obtained.

[0032] The solar cell may further include a sealing resin that covers at least the region of the photoelectric conversion unit that is surrounded by the insulating resin, and at least a portion of the upper surface of the insulating resin that is parallel to the substrate may be covered with the sealing resin, thereby protecting the light-receiving surface of the photoelectric conversion unit.

[0033] In the solar cell described above, the outer edges of the substrate, the buffer layer, and the sealing resin may be flush with each other, which makes it easier to form the sealing resin.

[0034] In the solar cell described above, the upper surface of the buffer layer parallel to the substrate may be exposed without being covered with the sealing resin, which makes it difficult for external forces acting on the side surfaces of the solar cell to be transmitted to the sealing resin.

[0035] In the solar cell described above, another part of the upper surface of the insulating resin may be covered with a buffer layer, which makes it difficult for external forces applied to the side surfaces of the solar cell to be transmitted by the sealing resin.

[0036] A method for manufacturing a solar cell according to one aspect of the present disclosure includes a first step of forming a photoelectric conversion unit on a surface of a film-like substrate, a second step of forming an insulating resin on the substrate so as to cover an outer edge of the photoelectric conversion unit, a third step of forming a buffer layer on the substrate so as to cover the outer edge of the insulating resin, the buffer layer having a Young's modulus lower than that of the insulating resin, and a fourth step of cutting the substrate along the buffer layer to singulate the solar cell. This method makes it possible to prevent damage to the photoelectric conversion unit and the like because the force applied during singulation is absorbed by the buffer layer.

[0037] The method for manufacturing a solar cell described above may further include, after the third step and before the fourth step, a step of forming a sealing resin that covers the photoelectric conversion section, the insulating resin, and the buffer layer, and in the fourth step, the substrate and the sealing resin may be cut along the buffer layer, which facilitates the formation of the sealing resin.

[0038] The method for manufacturing a solar cell described above may further include, after the third step and before the fourth step, a step of forming a sealing resin that covers at least the region of the photoelectric conversion section surrounded by the insulating resin without covering the buffer layer, and in the fourth step, the substrate may be cut along the buffer layer without cutting the sealing resin, which makes it less likely that force will be applied to the sealing resin during singulation.

[0039] This application claims the benefit of Japanese Patent Application No. 2024-005925, filed on January 18, 2024, the entire disclosure of which is incorporated herein by reference.

[0040] REFERENCE SIGNS LIST 10 Substrate 11 Surface of substrate 12 Outer edge of substrate 20 Photoelectric conversion section 21 Outer edge of photoelectric conversion section 22 Light receiving surface 30 Insulating resin 31 Outer edge of insulating resin 32 Inner edge of insulating resin 33 Upper surface of insulating resin 40 Buffer layer 41 Outer edge of buffer layer 42 Upper surface of buffer layer 50 Sealing resin 51 Outer edge of sealing resin 60 Pinnacle blade 100 Solar cell F1, F2 Force applied to solar cell

Claims

1. A solar cell, comprising: a film-like substrate; a photoelectric conversion unit provided on the substrate; an insulating resin provided on the substrate and covering an outer edge portion of the photoelectric conversion unit; and a buffer layer provided on the substrate, covering an outer edge portion of the insulating resin, and having a lower Young's modulus than the insulating resin, wherein an outer edge portion of the buffer layer is exposed.

2. The solar cell according to claim 1, wherein the insulating resin is made of a thermosetting resin material, and the buffer layer is made of a thermoplastic resin material.

3. The solar cell according to claim 1, further comprising a sealing resin that at least covers a region of the photoelectric conversion unit surrounded by the insulating resin, and at least a part of an upper surface of the insulating resin parallel to the substrate is covered by the sealing resin.

4. The solar cell according to claim 3, wherein an outer edge portion of the substrate, the outer edge portion of the buffer layer, and an outer edge portion of the sealing resin form the same plane.

5. The solar cell according to claim 3, wherein an upper surface of the buffer layer parallel to the substrate is exposed without being covered by the sealing resin.

6. The solar cell according to claim 5, wherein another part of the upper surface of the insulating resin is covered by the buffer layer.

7. A method for manufacturing a solar cell, comprising: a first step of forming a photoelectric conversion unit on a surface of a film-like substrate; a second step of forming an insulating resin on the substrate so as to cover an outer edge portion of the photoelectric conversion unit; a third step of forming a buffer layer having a lower Young's modulus than the insulating resin on the substrate so as to cover an outer edge portion of the insulating resin; and a fourth step of dicing the substrate along the buffer layer to form individual pieces.

8. The method for manufacturing a solar cell according to claim 7, further comprising a step of forming a sealing resin that covers the photoelectric conversion unit, the insulating resin, and the buffer layer after the third step and before the fourth step, and in the fourth step, dicing the substrate and the sealing resin along the buffer layer.

9. The method for manufacturing a solar cell according to claim 7, further comprising a step of forming a sealing resin that at least covers a region of the photoelectric conversion unit surrounded by the insulating resin without covering the buffer layer after the third step and before the fourth step, and in the fourth step, dicing the substrate along the buffer layer without dicing the sealing resin.

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