Flexible encapsulating film for space solar cell and method for preparing the same

Abstract

The application discloses a flexible packaging film for space solar cells and a preparation method thereof, and belongs to the technical field of solar cells. x 0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S; wherein: S represents a SiO2 film layer with 1 / 4 optical thickness at a reference wavelength, the coefficient before S represents a coefficient adjustment on the basis of the film layer thickness; T represents a TiO x 0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S; wherein: S represents a SiO2 film layer with 1 / 4 optical thickness at a reference wavelength, the coefficient before S represents a coefficient adjustment on the basis of the film layer thickness; T represents a TiO x 0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S; wherein: S represents a SiO2 film layer with 1 / 4 optical thickness at a reference wavelength, the coefficient before S represents a coefficient adjustment on the basis of the film layer thickness; T represents a TiO x 0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S; wherein: S represents a SiO2 film layer with 1 / 4 optical thickness at a reference wavelength, the coefficient before S represents a coefficient adjustment on the basis of the film layer thickness; T represents a TiO x 0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S; wherein: S represents a SiO2 film layer with 1 / 4 optical

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of solar cells, and particularly relates to a flexible packaging film for space solar cells and a preparation method thereof. BACKGROUND

[0002] The current solar cell technology is developing rapidly, and the conversion efficiency of space solar cells is gradually increasing. In order to reduce the launch mass and volume of a spacecraft and reduce the launch cost, a high-efficiency flexible gallium arsenide solar cell emerges as the times require.

[0003] The flexible gallium arsenide solar cell is prepared by using a gallium arsenide wafer as an epitaxial substrate, using a MOCVD technology to epitaxially grow an epitaxial structure on the surface of the gallium arsenide wafer, and performing a series of semiconductor processes such as evaporation of a seed layer, electroplating of a support substrate, bonding of a temporary substrate, etching of the gallium arsenide substrate, preparation of an upper electrode and an anti-reflection film, dicing, and removal of the temporary substrate. The thickness of the flexible gallium arsenide solar cell is only about 40 microns, and the area density can be reduced to one third of that of a traditional 150-micron-thick solar cell, so that the total launch weight can be greatly reduced. At the same time, the flexible gallium arsenide solar cell can be bent to a certain extent without damaging the structure of the solar cell, so that the solar cell array can be designed in a winding structure, which greatly saves the launch volume compared with a traditional rigid solar cell panel.

[0004] The external packaging of a traditional solar cell uses a rigid radiation-resistant glass cover, which cannot meet the requirements of lightweight and bendability for flexible solar cell packaging. Therefore, an ETFE or other organic thin film material is currently used to realize the packaging of the flexible solar cell. The ETFE has a relatively high transmission effect, but cannot achieve the same cut-off absorption effect as the radiation-resistant glass cover in the ultraviolet band, so that the sealing glue below the thin film cannot resist the ultraviolet radiation in the space environment, thereby causing aging and degeneration, and reducing the working life and conversion efficiency of the flexible solar cell array. SUMMARY

[0005] The present application provides a flexible packaging film for space solar cells and a preparation method thereof, which can achieve cut-off absorption in the ultraviolet band and high transmission effect in the working band 400nm-1300nm of the flexible gallium arsenide solar cell, thereby improving the on-orbit working life of the flexible solar cell array on the premise of ensuring the on-orbit efficiency of the flexible gallium arsenide solar cell.

[0006] The first object of the present application is to provide a flexible packaging film for space solar cells, which comprises an ETFE film, and a SiO2 film layer and a TiO2 film layer of the following structure are sequentially and alternately deposited on the upper surface of the ETFE film. xFilm layers: | 0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S |; wherein: S represents a SiO2 film layer with 1 / 4 optical thickness at a reference wavelength, the coefficient before S represents a coefficient adjustment based on the thickness of the film layer; T represents a TiO x Film layers, x ranges from 1.5 to 2, the coefficient before T represents a coefficient adjustment based on the thickness of the film layer

[0007] The second object of the present application is to provide a preparation method of a flexible packaging film for a space solar cell, comprising:

[0008] S1, after surface cleaning treatment, the ETFE film is put into a vacuum chamber;

[0009] S2, in a vacuum environment, argon is introduced to ignite the vacuum chamber, and then oxygen is introduced;

[0010] S3, according to the film layer structure of ETFE | 0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S | Air, SiO2 film layer and TiO x Film layers are alternately deposited on the surface of the ETFE film; wherein: S represents a SiO2 film layer with 1 / 4 optical thickness at a reference wavelength, the coefficient before S represents a coefficient adjustment based on the thickness of the film layer; T represents a TiO x Film layers, x ranges from 1.5 to 2, the coefficient before T represents a coefficient adjustment based on the thickness of the film layer; Air represents air;

[0011] S4, after deposition, the vacuum chamber is opened and the flexible packaging film is taken out.

[0012] Preferably, the refractive index of the SiO2 film layer ranges from 1.44 to 1.46; the refractive index of the TiO x The refractive index of the TiO

[0013] Preferably, the reference wavelength corresponding to the above-mentioned refractive index and thickness is 630 nm.

[0014] Preferably, the deposition rate of the SiO2 film layer is 0.4 nm / s to 0.6 nm / s, and the deposition rate of the TiO x The deposition rate of the TiO

[0015] Preferably, the deposition rate of the SiO2 film layer is 0.5 nm / s, and the deposition rate of the TiO x The deposition rate of the TiO

[0016] A second objective of this invention is to provide a flexible encapsulation film for space solar cells, characterized in that it is obtained by the above-described method for preparing the flexible encapsulation film for space solar cells.

[0017] The advantages and positive effects of this invention are:

[0018] Flexible encapsulation films utilize the interference effect of multilayer interference films and the ultraviolet absorption effect of titanium dioxide material itself to achieve cutoff absorption in the ultraviolet band and high transmission in the 400nm–1300nm operating band of flexible gallium arsenide solar cells, combining the advantages of radiation-resistant glass covers and ETFE films. Applying flexible encapsulation films to the encapsulation of flexible solar cells can improve the on-orbit lifespan of flexible solar cell arrays while ensuring the on-orbit efficiency of flexible gallium arsenide solar cells.

[0019] The film materials used in flexible packaging films are all commonly used in space environments and have good space environment tolerance. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the flexible encapsulation film.

[0021] Figure 2 These are the transmittance curves of the ETFE thin film substrate and the flexible encapsulation film proposed in this invention. Detailed Implementation

[0022] To further understand the content, features, and effects of this invention, the following embodiments are provided, and detailed descriptions are given below in conjunction with the accompanying drawings:

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the technical solutions of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0025] Please see Figure 1 and Figure 2A flexible encapsulation film for space solar cells includes an ETFE film, on the upper surface of which SiO2 film layers and TiO2 layers with the following structure are sequentially and alternately deposited. x Film thickness: │0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S│; where: S represents a SiO2 film with 1 / 4 optical thickness at the reference wavelength, and the coefficient before S represents the coefficient adjustment based on the film thickness; T represents a TiO2 film with 1 / 4 optical thickness at the reference wavelength. x For the film layer, x ranges from 1.5 to 2, and the coefficient before T represents the coefficient adjustment based on the film layer thickness.

[0026] A method for preparing a flexible encapsulation film for space solar cells, comprising:

[0027] (1) After the ETFE film is cleaned, it is placed in a vacuum chamber and the ETFE film is kept flat.

[0028] (2) Close the vacuum chamber door and evacuate the vacuum. After the vacuum level meets the requirements, introduce the working gas argon in sequence to make the vacuum chamber glow, and then introduce the reaction gas oxygen.

[0029] (3) SiO2 and TiO2 films were alternately deposited on the ETFE surface according to the film structure of ETFE│0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S│Air. x Membrane.

[0030] (4) During the deposition process, the SiO2 film deposition rate was 0.5 nm / s, and the TiO2 film deposition rate was 0.5 nm / s. x The film deposition rate is 0.3 m / s.

[0031] (5) After deposition, open the vacuum chamber and remove the flexible encapsulation film.

[0032] (6) The transmittance of the flexible encapsulation film was tested, and the transmittance curve was obtained as shown in the figure. Figure 2 As shown.

[0033] A schematic diagram of the flexible encapsulation film is shown below. Figure 1 As shown, the encapsulation film uses an ETFE film as a substrate, on which multiple layers of aperiodic optical films are deposited. The specific structure is as follows:

[0034] ETFE│0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S│Air

[0035] Where: ETFE represents ETFE substrate, and Air represents air.

[0036] S represents a SiO2 film with 1 / 4 optical thickness at the reference wavelength, and the coefficient before S represents a coefficient adjustment based on the above film thickness.

[0037] T represents TiO₂ with a thickness of 1 / 4 optical thickness at the reference wavelength. x (Titanium oxide, x ranges from 1.5 to 2) film, the coefficient before T represents the coefficient adjustment based on the above film thickness.

[0038] The refractive index range of the SiO2 film is 1.44 to 1.46.

[0039] The above-mentioned TiO x The refractive index of the film ranges from 2.15 to 2.25.

[0040] The reference wavelength corresponding to the above refractive index and thickness is 630nm.

[0041] The flexible encapsulation film was prepared using reactive magnetron sputtering, with various oxide layers alternately deposited on the ETFE surface. Oxygen and argon gases were introduced during the deposition process. The SiO2 film deposition rate was 0.4 nm / s to 0.6 nm / s, and the TiO2 film deposition rate was... x The film deposition rate is 0.25 nm / s to 0.35 nm / s.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A flexible encapsulation film for space solar cells, characterized in that, The film includes an ETFE thin film, on the upper surface of which SiO2 film layers and TiO2 layers are sequentially and alternately deposited with the following structure. x Film thickness: │0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S│; where: S represents a SiO2 film with 1 / 4 optical thickness at the reference wavelength, and the coefficient before S represents the coefficient adjustment based on the film thickness; T represents a TiO2 film with 1 / 4 optical thickness at the reference wavelength. x For the film layer, x ranges from 1.5 to 2, and the coefficient before T represents the coefficient adjustment based on the film layer thickness.

2. A method for preparing a flexible encapsulation film for space solar cells, characterized in that, include: S1. After surface cleaning, the ETFE film is placed in a vacuum chamber; S2. In a vacuum environment, argon gas is introduced sequentially to make the vacuum chamber glow, and then oxygen gas is introduced. S3. According to the film structure of ETFE│0.12S, 0.03T, 0.14S, 0.10T, 0.08S, 0.14T, 0.09S, 0.08T, 0.27S│Air, SiO2 film and TiO2 film are alternately deposited on the surface of ETFE film. x membrane; Where: S represents a SiO2 film with 1 / 4 optical thickness at the reference wavelength, and the coefficient before S represents a coefficient adjustment based on the film thickness; T represents a TiO2 film with 1 / 4 optical thickness at the reference wavelength. x For the film layer, x ranges from 1.5 to 2; the coefficient before T represents the coefficient adjustment based on the film layer thickness; Air represents air. S4. After deposition is complete, open the vacuum chamber and remove the flexible encapsulation film.

3. The method for preparing the flexible encapsulation film for space solar cells according to claim 2, characterized in that, The refractive index of the SiO2 film ranges from 1.44 to 1.46; the TiO2 film... x The refractive index of the film ranges from 2.15 to 2.

25.

4. The method for preparing the flexible encapsulation film for space solar cells according to claim 3, characterized in that, The reference wavelength corresponding to the above refractive index and thickness is 630nm.

5. The method for preparing the flexible encapsulation film for space solar cells according to claim 2, characterized in that, The deposition rate of SiO2 film is 0.4 nm / s to 0.6 nm / s, and that of TiO2 film is 0.4 nm / s to 0.6 nm / s. x The deposition rate of the film is 0.25 nm / s to 0.35 nm / s.

6. The method for preparing the flexible encapsulation film for space solar cells according to claim 5, characterized in that, The deposition rate of the SiO2 film is 0.5 nm / s, and the deposition rate of the TiO2 film is 0.5 nm / s. x The deposition rate of the film was 0.3 m / s.

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