TWI497736B - A Process Method for Anti - reflective Packaging Film of Solar Cell - Google Patents

Description

Method for manufacturing solar cell anti-reflection packaging film

The invention relates to a method for manufacturing a solar cell encapsulating film, in particular to a method for manufacturing a solar cell anti-reflective encapsulating film.

With the growing problem of the energy crisis, the relevant green energy industry is actively seeking various alternative oil resources, among which the most common alternatives to solar power generation are the types of solar cells currently on the market: twin solar cells, thin film solar cells ( Gallium indium indium selenide (CIGS), cadmium telluride (CdTe), amorphous germanium (a-Si), etc., and III-V semiconductors, and in order to enable solar cells to absorb more light, resulting in higher efficiency, Anti-reflection has always been one of the main directions of performance research.

The conventional anti-reflection layer comprises a single layer and a multi-layer structure, and the single layer structure has the advantages of economy and thickness, but since the sunlight is not a single wavelength, the solar panel is preliminarily obtained under the illumination of a wide wavelength range of sunlight. For reflectivity, a multilayer anti-reflective structure must be used, but the multilayer anti-reflective structure contains a more complicated preparation procedure and is costly.

Regarding the life of solar cells, the ability of solar cells to block water vapor and block oxygen affects the passivation and lifetime of solar cells. For example, the water vapor transmission rate of electronic paper packages requires about 10 ^-1 g/m ^{2 .} -day, the water vapor transmission rate of the liquid crystal display is required to be about 10 ^-2 g/m ² -day, but the water vapor transmission rate of the solar cell is required to be about 10 ^-6 g/m ² -day, therefore, Solar cells are relatively sensitive to moisture and oxygen, and must be sealed with water and oxygen.

However, the production of a good anti-reflection layer and encapsulation film, the complex preparation process will increase the cost of the solar cell, but the solar cell can not be without a good anti-reflection layer and package module, so the industry is in great need to develop a solar cell resistance The method for processing the reflective encapsulation film can combine the anti-reflection layer and the encapsulation film, thereby simplifying the process and reducing the cost, so that the cost can be simultaneously maintained and the optical characteristics can be maintained, thereby reducing the coupling of the light. An anti-reflective encapsulation film that increases light capture rate and improves overall solar module efficiency by light out-coupling.

In view of the above disadvantages of the prior art, the main object of the present invention is to provide a method for manufacturing a solar cell anti-reflective packaging film, integrating a low refractive index waveguide material, a curing agent, a mold having a microstructure at the bottom, etc. An anti-reflective encapsulating film which can be applied to reduce light out-coupling, improve light capturing rate, and improve overall solar module efficiency is prepared.

In order to achieve the above object, according to one aspect of the present invention, a method for fabricating a solar cell anti-reflective encapsulating film, comprising: mixing a waveguide material having a low refractive index with a curing agent to form a mixed solution; The liquid is placed in a mold and a curing process is performed to solidify the mixture Forming an anti-reflection portion, wherein the bottom of the mold has a microstructure; placing a solar cell on the anti-reflection portion; placing the mixture in the mold again, and heating to solidify the mixture and The anti-reflective film forms an anti-reflective encapsulation film, wherein the anti-reflective encapsulation film completely covers the solar cell.

In the above method for manufacturing a solar cell anti-reflective encapsulating film, a low refractive index waveguide material refers to a material having a lower refractive index than a solar cell (for example, a CIGS solar cell n>2.3, so a material having n between 1.4 and 1.8) That is, but not limited to, and a light transmissive material having a high transparency, for example, a low refractive index waveguide material may be selected from the group consisting of acrylic (PMMA), polyvinyl alcohol, polyvinyl acetate (PVA), One of PVP (Polyvinyl pyrrolidone), EVA (Ethylene vinyl acetate copolymer), and polydimethyl siloxane (PDMS), wherein the ratio of the polydimethyl siloxane (PDMS) to the curing agent may be 10: 1.

In the method for manufacturing the solar cell anti-reflective encapsulating film, the microstructure may be provided by a template having a nano-micro structure placed on the bottom of the mold, or a nano-micro structure may be disposed at the bottom of the mold.

The curing procedure of the present invention may be performed by using a heating procedure to cure the mixture, or by using an actinic (lighting) procedure to cure the mixture, or by mixing the two processes depending on the curing agent. The nature of the heat curing agent may be one of phenol resin, epoxy resin, polythenimine, cyanate ester or a mixture thereof (but not limited thereto), and the light curing agent may be UV glue (but not Limited to this); the so-called heating procedure to cure the mixture refers to The curing agent is reacted by heating to produce the mixed liquid from a liquid state to a solid state; the so-called photochemical process to cure the mixed liquid means that the curing agent (for example, UV glue) is reacted by illumination to produce the mixture. The liquid is converted from a liquid state to a solid state; the above-mentioned curing agent, whether subjected to heating or an actinic process, can be subjected to a vacuum defoaming process, and the curing agent is placed in a vacuum apparatus for vacuum defoaming.

In the present invention, the thickness of the anti-reflection portion may range from 1 to 5 mm, wherein the anti-reflection portion may be 2 mm or 3 mm.

The above summary and the following detailed description and drawings are intended to further illustrate the manner, means and effects of the present invention in achieving its intended purpose. Other purposes and advantages of this creation will be explained in the following description and drawings.

11‧‧‧Mold

12‧‧‧Microstructures (templates with nanostructures)

13‧‧‧ mixture

14‧‧‧heater

15‧‧‧Solar battery

16‧‧‧Anti-reflection department

17‧‧‧Anti-reflective encapsulation film

S191-S197‧‧‧Steps

The first figure is a flow chart of a method for manufacturing a solar cell anti-reflective encapsulating film according to the present invention; the second figure is a comparison chart of an IV with an anti-reflective encapsulating film of 2 mm and a bare cell of a solar cell; Inventively compares an IV with a 3 mm anti-reflective encapsulation film and a solar cell die.

The embodiments of the present invention are described below by way of specific specific examples, and those skilled in the art can easily as disclosed in the present specification. Understand the advantages and effects of this creation.

The invention provides a process method for encapsulation with a low refractive index material. By integrating the refractive index difference with the solar cell to achieve anti-reflection function and packaging into a solar module, many transparent plastic materials can be used for fabricating waveguides, for example. : PMMA (acrylic), PVA (polyvinyl alcohol), PVP, and PDMS (dimethyloxane).

Please refer to the first figure, which is a flow chart of a method for manufacturing a solar cell anti-reflective packaging film according to the present invention. As shown in the figure, the present invention provides a method for manufacturing a solar cell anti-reflective encapsulating film, comprising: preparing a mold (S191), preparing a mold (11), and placing a template having a nano-micro structure at the bottom of the mold (11) (12) a waveguide material containing a low refractive index is mixed with a curing agent to form a mixed liquid (13), which can be uniformly stirred and then allowed to stand for a while or placed in a vacuum chamber to remove air bubbles; The liquid (13) is placed in a mold (11) (S192), and a curing process is performed to cure the mixture to form an anti-reflection portion (S193), wherein the curing process in the first figure is a heater (14) heating the mixed liquid (13), but the invention is not limited thereto; a solar cell is placed on the anti-reflection portion (16) (S194); and the mixed liquid (13) is placed in the mold again. (11), and performing the curing process (S195) to cure the mixed liquid (13) and form an anti-reflection encapsulating film with the anti-reflection portion (16) (S196); and the solar cell module (18) The anti-reflection encapsulating film (17) is taken out from the mold (S197).

Example

In this embodiment we use PDMS to make an anti-reflective encapsulation film. (anti-reflection encapsulant, AR encapsulant), and reprinting the microstructure to the light-receiving surface of the solar cell in a mold mode, the PDMS refractive index (n) is about 1.42, which has a lower refractive index than the solar cell, for example: CIGS solar cell n>2.3, therefore, PDMS can produce good anti-reflection effect by the difference of refractive index and good waveguide characteristics, which can increase the light absorption of the battery by light trapping, thereby improving the power generation efficiency and the function of package molding. In addition, PDMS can use the soft lithography technology to fabricate the micro-optical structure on the light-receiving surface, thereby reducing the light out-coupling and improving the light-trapping rate and improving the overall module efficiency. The detailed process of this embodiment is as follows:

1. Calculate the required volume of the PDMS mixture for the thickness of the anti-reflective encapsulating film to be retained. According to the design of the thickness of the anti-reflection portion (the thickness of the embodiment is 2 mm and 3 mm), absorb the appropriate amount of PDMS and add the curing agent in proportion (PDMS: curing agent). =10:1), after standing evenly, let stand for a period of time or placed in a vacuum chamber to remove bubbles. The PDMS may be DOW CORNING's SYLGARD 184A, and the curing agent may be DOW CORNING's SYLGARD 184B.

2. After the bubble is completely removed, pour the appropriate volume of the mixture into the mold and place it on the heating plate to heat the PDMS (90~120 °C, which can be adjusted according to the pouring dose and process time). The bottom of the mold can be placed first. Template of structure;

3. Place the solar cell and pour the bubbled PDMS mixture. After the mixed liquid is covered with the battery, the mold is placed on the heating plate to heat and cure the PDMS;

4. After the PDMS is completely cured, the mold is removed from the heating plate, and after standing and cooling, the module is removed from the mold.

Please refer to the second figure, which is a comparison diagram of an IV with an anti-reflective encapsulation film and a solar cell die according to the present invention; please refer to the third figure, which shows a 3 mm anti-reflective encapsulation film and a bare solar cell of the present invention. The IV comparison chart of the film. As shown in the figure, after a low refractive index PDMS encapsulation film is applied outside the solar cell, the photocurrent is significantly improved, and a solar cell having a 2 mm AR encapsulant film is compared with an unpackaged solar cell die. The photocurrent is increased by 17.1%, and the solar cell with 3mm AR encapsulant has an optical current of 22.5% compared with the unpackaged solar cell die. In addition, the soft lithography process will be used. The micro-optical lens structure (micro-structure) with a focal length of 3.9mm (F/3.9) is rewound to a solar cell (3mm+F/3.9 AR encapsulant) with a 3mm anti-reflective encapsulation film, and its current is increased from the original 35.77mA. At 46.48 mA, the efficiency is increased from 11.99% to 15.58%, which proves that the micro-optical structure (micro-structure) can effectively reduce the optical coupling loss and improve the power conversion efficiency (PCE). One listed.

Solar cell packaging technology is a key technology from semi-finished products to finished products in the process of solar cell products. The main function is to thermally or curate the solar cells of the substrate and the series-parallel connection (thermal-cured or UV-cured packaging materials). Encapsulant), with a backsheet to make the module more robust, weather resistant and safe, and the invention combines the anti-reflective layer with the encapsulation film, which not only simplifies the process but also reduces The cost, combined with both economic and optical characteristics, enables the preparation of an anti-reflective encapsulation film that reduces light out-coupling, increases light capture, and improves overall solar module efficiency.

The above-described embodiments are merely illustrative of the features and functions of the present invention and are not intended to limit the scope of the technical content of the present invention. Anyone who is familiar with this skill can do so without violating the spirit and scope of creation. The examples are modified and varied. Therefore, the scope of protection of this creation should be as listed in the scope of the patent application described later.

11‧‧‧Mold

12‧‧‧Microstructures (templates with nanostructures)

13‧‧‧ mixture

14‧‧‧heater

15‧‧‧Solar battery

16‧‧‧Anti-reflection department

17‧‧‧Anti-reflective encapsulation film

S191-S197‧‧‧Steps

Claims (10)

A method for manufacturing a solar cell anti-reflective encapsulating film, comprising: mixing a waveguide material having a low refractive index with a curing agent to form a mixed solution; placing the mixed solution in a mold, and performing a curing process to make the mixed solution Curing to form an anti-reflection portion, wherein the bottom of the mold has a microstructure; a solar cell is placed on the anti-reflection portion; the mixture is placed in the mold, and the curing process is performed to cure the mixture And forming an anti-reflective encapsulation film with the anti-reflection film, wherein the anti-reflection encapsulation film completely covers the solar cell. The method for manufacturing a solar cell anti-reflective encapsulating film according to claim 1, wherein the low refractive index waveguide material is selected from the group consisting of acrylic (PMMA), polyvinyl alcohol (PVA), PVP, EVA, and poly One of methyl oxane (PDMS). The method for preparing a solar cell anti-reflective encapsulating film according to claim 2, wherein the polydimethylsiloxane (PDMS) and the curing agent are mixed at a ratio of 10:1. The method for manufacturing a solar cell anti-reflective encapsulating film according to claim 1, wherein the micro-structure is provided by a template having a nano-micro structure. The method for manufacturing a solar cell anti-reflective encapsulating film according to claim 1, wherein the mixed solution is placed in a vacuum environment for defoaming. The method for manufacturing a solar cell anti-reflective encapsulating film according to claim 3, wherein the anti-reflection portion has a thickness ranging from 1 to 5 mm. The method for manufacturing a solar cell anti-reflective encapsulating film according to claim 3, wherein the anti-reflection portion has a thickness of 2 mm. The method for manufacturing a solar cell anti-reflective encapsulating film according to claim 3, wherein the anti-reflection portion has a thickness of 3 mm. The method for manufacturing a solar cell anti-reflective encapsulating film according to claim 1, wherein the curing process is a heating process. The method for manufacturing a solar cell anti-reflective encapsulating film according to claim 1, wherein the curing process is an actinic process.