Photovoltaic module and method for manufacturing the same

Abstract

The present invention provides a photovoltaic module and a method for manufacturing the same that can reduce manufacturing costs. [Solution] The photovoltaic module 1 is generally composed of a substrate 2 on which uneven surfaces 24 are provided on the substrate surface 20, and a transparent electrode layer 3 which is transparent and conductive and has irregular recesses 31 on the surface 30 that are traces left when air bubbles 10 generated due to the uneven surfaces 24 detach. This photovoltaic module 1 can achieve a high light confinement effect while suppressing manufacturing costs.

Description

Technical Field

[0001] The present invention relates to a photovoltaic module and a method for manufacturing the same.

Background Art

[0002] As a conventional technique, a thin-film photoelectric conversion device that forms a concavo-convex structure on the surface of a transparent conductive film is known (see, for example, Patent Document 1).

[0003] This thin-film photoelectric conversion device forms a concavo-convex structure on the surface of the transparent conductive film by an etching process.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since a conventional thin-film photoelectric conversion device forms the concavo-convex structure of the transparent conductive film by an etching process, the manufacturing cost increases.

[0006] Therefore, an object of the present invention is to provide a photovoltaic module and a method for manufacturing the same that can suppress the manufacturing cost.

Means for Solving the Problems

[0007] One aspect of the present invention provides a photovoltaic module including a substrate provided with concavo-convex portions on the surface of the substrate, and a transparent electrode layer having transparency and conductivity and having irregular concave portions on the surface, which are traces when bubbles generated due to the concavo-convex portions are detached.

[0008] Another aspect of the present invention provides a method for manufacturing a photovoltaic module, which involves preparing a substrate on which irregularities are provided on the substrate surface, applying a transparent electrode material having transparency and conductivity to the substrate surface, and forming a transparent electrode layer by vacuum treatment to create irregular recesses on the surface that are traces of air bubbles generated due to the irregularities detaching. [Effects of the Invention]

[0009] According to the present invention, manufacturing costs can be reduced. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1(a) is a cross-sectional view showing an example of the substrate, transparent electrode layer, and conductive resin layer of a photovoltaic module according to an embodiment, and Figure 1(b) is a top view showing an example of an uneven surface. [Figure 2] Figure 2 is a cross-sectional view showing an example of a photovoltaic module according to an embodiment. [Figure 3] Figures 3(a) to 3(d) show an example of a method for manufacturing a photovoltaic module according to an embodiment. [Modes for carrying out the invention]

[0011] (Summary of the embodiment) The photovoltaic module according to this embodiment is generally configured to include a substrate on which an uneven surface is provided, and a transparent electrode layer that is transparent and conductive and has irregular recesses on its surface which are traces of air bubbles generated due to the uneven surface and then detach.

[0012] Furthermore, the method for manufacturing a photovoltaic module includes preparing a substrate on which irregularities are provided on the substrate surface, applying a transparent electrode material having transparency and conductivity to the substrate surface, and forming a transparent electrode layer by creating irregular depressions on the surface, which are traces of air bubbles generated due to the irregularities, through vacuum processing.

[0013] This photovoltaic module and its manufacturing method form irregular depressions on the surface of the transparent electrode layer when bubbles caused by uneven surfaces detach. Compared to forming them by etching, this method allows for formation during the transparent electrode layer formation process, thereby reducing manufacturing costs.

[0014] [Embodiment] (Overview of Photovoltaic Module 1) Figure 1(a) is a cross-sectional view showing an example of the substrate, transparent electrode layer, and conductive resin layer of a photovoltaic module according to an embodiment, and Figure 1(b) is a top view showing an example of an uneven portion. Figure 2 is a cross-sectional view showing an example of a photovoltaic module according to an embodiment. Figures 3(a) to 3(d) show an example of a method for manufacturing a photovoltaic module according to an embodiment. Note that in the figures relating to the embodiments described below, the ratios and shapes between figures may differ from the actual ratios and shapes.

[0015] The photovoltaic module 1 is generally configured to include, for example, a substrate 2 on which uneven surfaces 24 are provided on the substrate surface 20, and a transparent electrode layer 3 which is transparent and conductive and has irregular recesses 31 on its surface 30 that are traces left when air bubbles 10 generated due to the uneven surfaces 24 detach.

[0016] Furthermore, as shown in Figure 1(a), the photovoltaic module 1 includes a conductive resin layer 4 provided on the surface 30 of the transparent electrode layer 3 by a conductive resin, and the layer surface 40 is flat.

[0017] The photovoltaic module 1 is a solar cell such as an organic solar cell, a silicon solar cell, a compound solar cell, or an organic-inorganic hybrid solar cell, but is not limited to these. In this embodiment, the photovoltaic module 1 is, as an example, a perovskite solar cell.

[0018] This perovskite solar cell is an organic-inorganic hybrid solar cell that is lightweight and has excellent flexibility. As shown in, for example, FIG. 2, the perovskite solar cell includes a photoelectric conversion layer 6 having a perovskite layer, a hole transport layer, and an electron transport layer, a lower electrode 5 provided on a substrate surface 20 of a substrate 2, and a sealing portion 8 that seals a part of the lower electrode 5, the photoelectric conversion layer 6, and an upper electrode 7, and is generally configured.

[0019] The lower electrode 5 includes a first electrode 51 and a second electrode 52. The first electrode 51 sandwiches the photoelectric conversion layer 6 together with the upper electrode 7. The second electrode 52 sandwiches the photoelectric conversion layer 6 together with the upper electrode 7 and is electrically connected to the upper electrode 7. A part of the first electrode 51 and the second electrode 52 is exposed outside the sealing portion 8 and outputs the converted electric power as an electrode terminal.

[0020] Therefore, one of the first electrode 51 and the second electrode 52 is a positive electrode and the other is a negative electrode. In the present embodiment, the first electrode 51 is a positive electrode and the second electrode 52 is a negative electrode.

[0021] The first electrode 51 and the second electrode 52 are formed, for example, by separating the lower electrode 5 using a laser.

[0022] The lower electrode 5 is composed of a transparent electrode layer 3 and a conductive resin layer 4.

[0023] (Configuration of Substrate 2) As an example, the substrate 2 is a film substrate formed using, but not limited to, PET (Polyethylene Terephthalate) that has excellent flexibility and high transparency.

[0024] As shown in FIG. 1(a), the concavo-convex portion 24 of the substrate 2 has a convex portion 22 and a concave portion 23, and the width W1 of the convex portion 22 is different from the width W2 of the concave portion 23. In the present embodiment, since the bubbles 10 mainly occur in the concave portion 23, the width W2 of the concave portion 23 is narrower than the width W1 of the convex portion 22.

[0025] Furthermore, the depth H of the recess 23 is preferably the same in order to detach the air bubbles 10 from the transparent electrode layer 3 without leaving any bubbles behind.

[0026] Furthermore, the protrusions 22 and recesses 23 are formed at equal intervals, as shown in Figures 1(a) and 1(b). The protrusions 22 and recesses 23 are formed over the entire surface of the substrate 20. These uneven surfaces 24 are formed, for example, by transferring a mold of the uneven surfaces 24 or by forming them with a chemical solution.

[0027] (Composition of transparent electrode layer 3) The transparent electrode layer 3 is formed from a substantially transparent material to allow light 9 incident from the back surface 21 of the substrate 2 to be incident on the photoelectric conversion layer 6, as shown in Figure 2, for example. Such materials include, for example, metal oxides, transparent conductive polymers, or transparent conductive inks. Examples of metal oxides include indium tin oxide (ITO) and indium zinc oxide (IZO). Examples of transparent conductive polymers include PEDOT / PSS (poly-3,4-ethylenedioxythiophene / polysulfonic acid). Examples of transparent conductive nanoinks include those containing carbon nanotubes and silver nanofibers in the binder, or those containing indium tin oxide (ITO).

[0028] The transparent electrode layer 3 in this embodiment is formed, for example, by a transparent conductive nanoink containing indium tin oxide (ITO), but is not limited thereto.

[0029] As shown in Figure 1(a), the transparent electrode layer 3 has irregular recesses 31 on its surface 30. These recesses 31 are formed to confine the incident light 9.

[0030] The recesses 31 originate from bubbles 10 that form on the uneven surfaces 24 of the substrate 2 when the material for forming the transparent electrode layer 3 is applied to the substrate 2 and then foams up. The bubbles 10 can be removed from the transparent electrode layer 3 by vacuum treatment. When the bubbles 10 remove from the transparent electrode layer 3, they form irregular recesses 31 on the surface 30 of the transparent electrode layer 3. The transparent electrode layer 3 is formed by curing before these recesses 31 disappear.

[0031] (Conductive resin layer 4) The conductive resin layer 4 is formed using, for example, a transparent conductive polymer, a resin material containing carbon nanotubes or graphene. This conductive resin layer 4 is provided in surface contact with the photoelectric conversion layer 6 to reduce resistance and efficiently collect current. Therefore, the conductive resin layer 4 has a flat surface 40, and the photoelectric conversion layer 6 is formed on this surface 40.

[0032] Furthermore, the photovoltaic module 1 may not require the conductive resin layer 4 depending on the configuration of the photoelectric conversion layer 6.

[0033] (Configuration of the photoelectric conversion layer 6) As described above, the photoelectric conversion layer 6 is configured to convert the light energy of the light 9 incident from the back surface 21 of the substrate 2 into electrical energy and output it from the first electrode 51 and the second electrode 52.

[0034] (Configuration of upper electrode 7) The upper electrode 7 is formed from a conductive material such as gold, silver, aluminum, and copper. The upper electrode 7 is, for example, formed from copper, but is not limited to this. For example, when light is taken in from the upper electrode 7 side, the upper electrode 7 may be configured as a transparent electrode. As shown in Figure 2, the upper electrode 7 has a protrusion 70 that is electrically connected to the second electrode 52.

[0035] (Configuration of sealing section 8) The sealing portion 8 is, for example, a PET-based film. This sealing portion 8 seals the upper electrode 7 and the like via an adhesive 80.

[0036] An example of a method for manufacturing the photovoltaic module 1 of this embodiment will be described below with reference to Figures 3(a) to 3(d).

[0037] (Manufacturing method for photovoltaic module 1) The method for manufacturing the photovoltaic module 1 includes preparing a substrate 2 on which uneven portions 24 are provided on the substrate surface 20, applying a transparent electrode material 35 having transparency and conductivity to the substrate surface 20, and forming a transparent electrode layer 3 on the surface 30 by vacuum treatment, which is the trace left when air bubbles 10 generated due to the uneven portions 24 detach.

[0038] Specifically, as shown in Figure 3(a), a substrate 2 is prepared in which the uneven portion 24 is provided on the substrate surface 20.

[0039] Next, as shown in Figure 3(b), a transparent electrode material 35 is applied to the substrate surface 20 of the substrate 2. The substrate 2 with the transparent electrode material 35 applied is then transported to a vacuum chamber. The transparent electrode material 35 is, for example, a transparent conductive nano-ink.

[0040] Next, as shown in Figure 3(c), a vacuum treatment is performed to lift the bubbles 10 that have formed in the uneven portion 24 and detach them from the transparent electrode material 35. At this time, the bubbles 10 form irregular recesses 31 on the surface 30.

[0041] Next, as shown in Figure 3(d), the air bubbles 10 detach and the curing process is performed with irregular depressions 31 formed. The vacuum treatment may be performed before or during curing.

[0042] Next, after curing is complete, the material is transported from the vacuum chamber, and a conductive resin layer 4 having a flat layer surface 40 is formed on the surface 30 of the transparent electrode layer 3 to obtain a substrate 2 having the lower electrode 5 shown in Figure 1(a).

[0043] (Effects of the embodiment) The photovoltaic module 1 according to this embodiment can reduce manufacturing costs. Specifically, the photovoltaic module 1 forms irregular recesses 31 on the surface 30 by releasing air bubbles 10 that inevitably occur when the transparent electrode material 35 is applied. Compared to forming recesses by etching or the like, these recesses can be formed during the process of forming the transparent electrode layer 3, thus reducing manufacturing costs while achieving a high light confinement effect.

[0044] Since the photovoltaic module 1 includes a conductive resin layer 4 having a flat layer surface 40 that contacts the photoelectric conversion layer 6, compared to a configuration without this setting, the incident light 9 is efficiently transmitted to the photoelectric conversion layer 6, a high light confinement effect is obtained, and the resistance between the lower electrode 5 and the photoelectric conversion layer 6 can be reduced.

[0045] In the photovoltaic module 1, the width W2 of the recess 23 is narrower than the width W1 of the protrusion 22. Therefore, compared to a configuration that does not employ this arrangement, it is possible to suppress the unnecessary generation of bubbles 10 and prevent bubbles 10 from remaining in the transparent electrode layer 3.

[0046] Since the photovoltaic module 1 has equal spacing between the convex portion 22 and the concave portion 23, the unevenness of the bubbles 10 is suppressed compared to a configuration that is not adopted, and the unevenly distributed concave portion 31 is formed on the surface 30 of the transparent electrode layer 3, thereby obtaining a high light confinement effect.

[0047] Although embodiments of the present invention have been described above, these embodiments are merely examples and do not limit the invention as defined in the claims. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Furthermore, not all combinations of features described in these embodiments are necessarily essential for solving the problem of the invention. Moreover, these embodiments are included in the scope and spirit of the invention, as well as in the invention described in the claims and its equivalents. [Explanation of symbols]

[0048] 1...Photovoltaic module, 2...Substrate, 3...Transparent electrode layer, 4...Conductive resin layer, 5...Lower electrode, 6...Photoelectric conversion layer, 7...Upper electrode, 8...Sealing part, 9...Light, 10...Air bubble, 20...Substrate surface, 21...Back surface, 22...Convex part, 23...Concave part, 24...Rough / uneven part, 30...Surface, 31...Concave part, 35...Transparent electrode material, 40...Layer surface, 51...First electrode, 52...Second electrode, 70...Protruding part, 80...Adhesive

Claims

1. A substrate having an uneven surface, A transparent electrode layer having transparency and conductivity, and having irregular recesses on its surface which are traces of air bubbles that have detached due to the uneven surface, A photovoltaic module equipped with this module.

2. The transparent electrode layer is provided with a conductive resin layer, the conductive resin layer having a flat surface, The photovoltaic module according to claim 1.

3. The uneven portion of the substrate has a convex portion and a concave portion, and the width of the convex portion and the width of the concave portion are different. The photovoltaic module according to claim 1 or 2.

4. Prepare a substrate in which an uneven surface is provided, A transparent electrode material having transparency and conductivity is applied to the surface of the substrate. By vacuum processing, irregular depressions, which are traces of air bubbles generated due to the uneven surface and then detached, are created on the surface to form a transparent electrode layer. A method for manufacturing photovoltaic modules.

5. Furthermore, a conductive resin layer having a flat layer surface is formed on the surface of the transparent electrode layer. A method for manufacturing a photovoltaic module according to claim 4.

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