Solar cell and method for manufacturing the same

Abstract

To prevent damage to a photoelectric conversion section during fragmentation in a method for manufacturing a solar cell using film-type substrates.SOLUTION: A method for manufacturing a solar cell 100 comprises a first step for forming a photoelectric conversion section 20 on the 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 the outer edge 21 of the photoelectric conversion section 20; a third step for forming a buffer layer 40 with a Young's modulus lower than that of the insulating resin 30 on the surface 11 of the substrate 10 so as to cover the outer edge 31 of the insulating resin 30; and a fourth step for cutting the substrate 10 along a buffer layer 40 to divide it into individual pieces.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a solar cell and a method for manufacturing the same, and more particularly, to a solar cell using a film-shaped substrate and a method for manufacturing the same.

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when cutting the substrate, stress is applied by the cutting blade, which may cause damage to the photoelectric conversion part or the like.

[0005] In the present disclosure, a technique for preventing damage to the photoelectric conversion part or the like during separation and improving the reliability of the solar cell is described in a solar cell using a film-shaped substrate and a method for manufacturing the same.

Means for Solving the Problems

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

[0007] According to one aspect of the present disclosure, a method for manufacturing a solar cell includes: a first step of forming a photoelectric conversion portion on the surface of a film-shaped substrate; a second step of forming an insulating resin on the substrate so as to cover the outer edge portion of the photoelectric conversion portion; 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 the outer edge portion of the insulating resin; and a fourth step of cutting the substrate along the buffer layer to individualize the substrate.

Effect of the Invention

[0008] According to the present disclosure, in a solar cell using a film-shaped substrate and a method for manufacturing the same, a technique is provided for preventing damage to a photoelectric conversion portion or the like during individualization and enhancing the reliability of the solar cell.

Brief Description of the Drawings

[0009]

Figure 1

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Figure 5

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Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[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 according to the present disclosure. Further, FIG. 2 is a schematic cross-sectional view along line A-A shown in FIG. 1.

[0012] As shown in FIGS. 1 and 2, the solar cell 100 according to the present embodiment includes a film-shaped substrate 10, a photoelectric conversion unit 20 provided on the surface 11 of the substrate 10, and an insulating resin 30 provided on the surface 11 of the substrate 10 and covering a region near the outer edge 21 among the outer edge 21 and the light-receiving surface 22 of the photoelectric conversion unit 20, 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-shaped member made of an insulating material such as polyethylene naphthalate, and functions as a support for the photoelectric conversion unit 20, the insulating resin 30, the buffer layer 40, and the sealing resin 50.

[0014] The photoelectric conversion unit 20 is a semiconductor element that converts incident light incident on the light-receiving surface 22 into electric power, and is formed on substantially the entire surface of the substrate 10 excluding the outer peripheral portion of the surface 11.

[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 material with high strength such as a thermosetting resin material. As an example, the insulating resin 30 can be constituted by a polyimide-based resin. The insulating resin 30 may contain a filler for adjusting characteristics.

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

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

[0018] In the example shown in FIG. 2, the outer edge portion 41 of the buffer layer 40 is exposed, and the outer edge portion 12 of the substrate 10, the outer edge portion 41 of the buffer layer 40, and the outer edge portion 51 of the encapsulating resin 50 form the same plane. Thus, since the outer edge portion 41 of the buffer layer 40 having 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 enhancing the reliability of the solar cell 100.

[0019] Figs. 3 to 5 are schematic diagrams for explaining a method of manufacturing the solar cell 100 according to the present embodiment. Note that Figs. 4 and 5 show cross-sections taken along the line B-B shown in Fig. 3.

[0020] First, as shown in Fig. 3, a plurality of photoelectric conversion units 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. In Fig. 3, the transparent sealing resin 50 is not shown. In the example shown in Fig. 3, four photoelectric conversion units 20 are formed on the surface 11 of the substrate 10. The number of the photoelectric conversion units 20 formed on the surface 11 of the substrate 10 is not particularly limited.

[0021] As shown in Fig. 4, in the formation of 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 portion 21 and the region near the outer edge portion 21 of the light-receiving surface 22 of the photoelectric conversion unit 20, respectively. In the formation of 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 portion 31 of the insulating resin 30. The formation of the insulating resin 30 and the buffer layer 40 can be performed, for example, by screen printing or inkjet printing. The sealing resin 50 may be formed over substantially the entire surface. That is, in the formation of 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 with the sealing resin 50.

[0022] As a result, as shown in Fig. 4, a state is obtained in which the buffer layer 40 is embedded between two adjacent solar cells 100 before singulation. That is, the buffer layer 40 is embedded between the outer edge portion 31 of the insulating resin 30 included in one solar cell 100 and the outer edge portion 31 of the insulating resin 30 included in the other solar cell 100.

[0023] Next, a plurality of solar cells 100 are separated by cutting the substrate 10 along the broken line C shown in FIG. 3. The broken line C is located in the buffer layer 40, and thus the substrate 10 is cut along the buffer layer 40. The cutting of the substrate 10 can be performed, for example, by pressing a pinnacle (registered trademark) blade 60 as shown in FIG. 5. When the pinnacle blade 60 is pressed, not only a force F1 acting in the intrusion direction of the pinnacle blade 60 acts on the pressed area, but also a lateral force F2 due to the thickness of the pinnacle blade 60 acts. However, in the present embodiment, since most of these forces F1 and F2 are absorbed by the buffer layer 40 having a low Young's modulus, the forces applied to the photoelectric conversion unit 20 and the insulating resin 30 during separation are significantly reduced. Thereby, it becomes possible to prevent damage to the photoelectric conversion unit 20 and the insulating resin 30 during separation.

[0024] In the example shown in FIG. 5, since the upper surface 42 of the buffer layer 40 is covered with the encapsulant resin 50, the encapsulant resin 50 covering the buffer layer 40 is also cut during separation. However, if the thickness of the encapsulant resin 50 located on the upper surface 42 of the buffer layer 40 is sufficiently thin, the encapsulant resin 50 will not be damaged during separation.

[0025] Alternatively, as in the first modification shown in FIG. 6, if the upper surface 42 of the buffer layer 40 is exposed without being covered with the encapsulant resin 50, the substrate 10 can be cut along the buffer layer 40 without cutting the encapsulant resin 50 during separation. Thereby, no force is applied to the encapsulant resin 50 during separation. In this case, in forming the encapsulant resin 50, the encapsulant resin 50 may be formed avoiding the buffer layer 40. In the solar cell 100 obtained by such a method, as shown in FIG. 7, the outer edge portion 51 of the encapsulant resin 50 is offset inward from the outer edge portion 41 of the buffer layer 40. Thereby, since the external force applied to the side surface of the solar cell 100 is less likely to be transmitted to the encapsulant resin 50, the reliability of the solar cell 100 is further enhanced.

[0026] Furthermore, as in the second modification shown in FIG. 8, not only the upper surface 42 of the buffer layer 40 is exposed without being covered with the encapsulant resin 50, but also a part of the upper surface 33 of the insulating resin 30 may be covered with the buffer layer 40. That is, a part of the upper surface 33 of the insulating resin 30 may be covered with the encapsulant resin 50 and another part of the upper surface 33 of the insulating resin 30 may be covered with the buffer layer 40. Also in this case, no force is applied to the encapsulant resin 50 during singulation. In the solar cell 100 obtained by such a method, as shown in FIG. 9, the outer edge portion 51 of the encapsulant resin 50 is covered with the buffer layer 40 without being exposed. As a result, an external force applied to the side surface of the solar cell 100 is less likely to be transmitted by the encapsulant resin 50, so that the reliability of the solar cell 100 is further enhanced.

[0027] As described above, in the solar cell 100 according to the present embodiment, since the substrate 10 is cut along the buffer layer 40 having a low Young's modulus during singulation, it is possible to prevent breakage during singulation. Moreover, after singulation, since the buffer layer 40 having 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 enhancing the reliability of the solar cell 100.

[0028] Although the embodiments of the technology according to the present disclosure have been described above, the technology according to the present disclosure is not limited to the above embodiments, and various modifications can be made without departing from the gist thereof, and it goes without saying that those are also included in 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-shaped substrate, a photoelectric conversion unit provided on the substrate, an insulating resin provided on the substrate and covering the outer edge portion of the photoelectric conversion unit, and a buffer layer provided on the substrate, covering the outer edge portion of the insulating resin, and having a lower Young's modulus than the insulating resin, and the outer edge portion of the buffer layer is exposed. According to this, the buffer layer exposed on the side surface of the solar cell makes it difficult for an external force to be transmitted to the photoelectric conversion unit, so the reliability of the solar cell is enhanced.

[0031] In the above solar cell, the insulating resin may be made of a thermosetting resin material, and the buffer layer may be made of a thermoplastic resin material. According to this, while sufficiently protecting the photoelectric conversion unit with the insulating resin made of a thermosetting resin material, it is possible to obtain high flexibility with the buffer layer made of a thermoplastic resin material.

[0032] The above solar cell may further include 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 the upper surface of the insulating resin parallel to the substrate may be covered by the sealing resin. According to this, the light-receiving surface of the photoelectric conversion unit is protected by the sealing resin.

[0033] In the above solar cell, the outer edge portion of the substrate, the outer edge portion of the buffer layer, and the outer edge portion of the sealing resin may form the same plane. According to this, the formation of the sealing resin becomes easy.

[0034] In the above solar cell, the upper surface of the buffer layer parallel to the substrate may be exposed without being covered by the sealing resin. According to this, it becomes difficult for an external force applied to the side surface of the solar cell to be transmitted to the sealing resin.

[0035] In the above solar cell, another part of the upper surface of the insulating resin may be covered by the buffer layer. According to this, it becomes difficult for an external force applied to the side surface of the solar cell to be transmitted by the sealing resin.

[0036] According to one aspect of the present disclosure, a method for manufacturing a solar cell includes a first step of forming a photoelectric conversion portion on the surface of a film-shaped substrate, a second step of forming an insulating resin on the substrate so as to cover the outer edge portion of the photoelectric conversion portion, 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 the outer edge portion of the insulating resin, and a fourth step of cutting the substrate along the buffer layer to individualize the substrate. According to this, since the force applied during individualization is absorbed by the buffer layer, it is possible to prevent damage to the photoelectric conversion portion and the like.

[0037] The above method for manufacturing a solar cell further includes a step of forming a sealing resin that covers the photoelectric conversion portion, the insulating resin, and the buffer layer after performing the third step and before performing the fourth step. In the fourth step, the substrate and the sealing resin may be cut along the buffer layer. According to this, it becomes easy to form the sealing resin.

[0038] The above method for manufacturing a solar cell further includes a step of forming a sealing resin that covers at least the region of the photoelectric conversion portion surrounded by the insulating resin without covering the buffer layer after performing the third step and before performing the fourth step. In the fourth step, the substrate may be cut along the buffer layer without cutting the sealing resin. According to this, it becomes difficult for force to be applied to the sealing resin during individualization.

Explanation of Signs

[0039] 10 Substrate 11 Surface of the substrate 12 Outer edge portion of the substrate 20 Photoelectric conversion portion 21 Outer edge portion of the photoelectric conversion portion 22 Light-receiving surface 30 Insulating resin 31 Outer edge portion of the insulating resin 32 Inner edge portion of the insulating resin 33 Upper surface of the insulating resin 40 Buffer layer 41 Outer edge portion of the buffer layer 42 Upper surface of the buffer layer 50 Sealing resin 51 Outer edge portion of the sealing resin 60 pinnacle blades 100 solar cells Forces F1, F2 applied to the solar cells

Claims

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

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

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

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

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

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

7. A first step of forming a photoelectric conversion unit 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 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 the outer edge portion of the insulating resin, and a fourth step of cutting the substrate along the buffer layer to individualize it. A method for manufacturing a solar cell.

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

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

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