CN118553803A - A method for packaging a space solar cell array resistant to ultraviolet radiation - Google Patents

Abstract

The present invention discloses a method for packaging a space solar cell array resistant to ultraviolet radiation. The present invention adopts a flexible packaging covering film, which reduces the weight of the battery, and is not easy to break when the wing is working and unfolding. At the same time, the covering film with ultraviolet radiation resistance and the adhesive are used in coordination, so that the covering film and the adhesive on the surface of the solar cell array are not easy to turn yellow under ultraviolet radiation in space, thereby increasing the working life of the battery array on track and obtaining stable power output.

Description

A method for packaging a space solar cell array resistant to ultraviolet radiation

Technical Field

The invention belongs to the technical field of solar cell packaging, and in particular relates to a method for packaging a space solar cell array resistant to ultraviolet radiation.

Background Art

With the rapid development of space technology and the complexity of space missions, the demand for space solar cells continues to increase. Space solar cells face more severe challenges than ever before, such as higher conversion efficiency and better radiation resistance. As the main power source for spacecraft, III-V multi-junction solar cells have become the main hotspot for space applications today due to their high efficiency and super strong radiation resistance. In recent years, new materials and new structures have also emerged, and the new solar cells constructed also have the characteristics of high efficiency, low cost, lightweight, flexibility and high power-to-weight ratio, showing the potential for space applications.

Unlike the ground environment, solar cells will be exposed to strong ultraviolet radiation, charged particle radiation, atomic oxygen and other harsh environments during their service in space, which will cause the battery performance to decay rapidly. In order to ensure the long-term stable operation of the battery, it is necessary to encapsulate the surface of the battery to shield the external environment. As the radiation protection layer of the solar cell, anti-radiation glass cover, transparent polyimide film, pseudo-glass cover and other thin films are usually used to cover the surface of the solar cell to protect the solar cell, and the battery and the surface covering film are bonded by adhesive. These materials have good high and low temperature resistance and high light transmittance, and are therefore commonly used materials for encapsulation of space solar cell arrays.

However, these packaging materials absorb ultraviolet light and degrade, which manifests as yellowing on a macro scale. In particular, the adhesive used has a rapid drop in transmittance after ultraviolet irradiation, resulting in power loss in the array. In order to improve the on-orbit power output stability of the solar array, we have adopted a new packaging method to package the solar array. Both the packaging film and the adhesive can transmit ultraviolet light and have good ultraviolet radiation resistance. They still have a high transmittance after long-term ultraviolet irradiation.

Summary of the invention

In view of the shortcomings of the prior art, the present invention provides a method for packaging a space solar cell array that is resistant to ultraviolet radiation. The present invention uses an ultraviolet-transmissive adhesive and a surface covering film to package the cell array. Both the surface covering film and the adhesive can transmit ultraviolet light and have ultraviolet radiation resistance. High light transmittance is achieved in the absorption band of the solar cell of 200-1300nm. While ensuring that the efficiency of the solar cell array is not lost, the working life of the cell array in orbit is improved.

The technical solution of the present invention is as follows:

The first aspect of the present invention provides a method for packaging a space solar cell array resistant to ultraviolet radiation, the packaging method comprising the following steps:

S1: coating an adhesive on the surface of the solar cell array to be packaged, and placing the surface of the substrate on the surface of the adhesive, and thermally curing the adhesive to obtain a solar cell array with the substrate on the back;

S2: In step S1, an adhesive is applied to the front side of the solar cell array including the substrate on the back side, a covering film is placed on the surface of the adhesive, and then thermally cured to obtain a packaged solar cell array.

Preferably, the solar cell array to be packaged includes at least one of a crystalline silicon solar cell array, a perovskite solar cell array, a gallium arsenide solar cell array, a copper indium gallium selenide solar cell array, a crystalline silicon-perovskite tandem solar cell array, and a copper indium gallium selenide-perovskite tandem solar cell array.

Preferably, in steps S1 and S2, the adhesive is silicone resin, has a light transmittance of >93%, and can transmit ultraviolet light of 200-400nm.

Preferably, in steps S1 and S2, the adhesive is resistant to temperature changes between -100°C and 100°C.

Preferably, in steps S1 and S2, the coating thickness of the adhesive is 10 to 200 μm.

Preferably, in steps S1 and S2, the thermal curing process is: first, keep the temperature at 50-60°C for 20-90 min, then heat up to 90-100°C, keep the temperature for 20-90 min, and finally heat up to 120-180°C, keep the temperature for 20-90 min.

Preferably, in step S2, the light transmittance of the covering film is greater than 93%, and the covering film can transmit ultraviolet light of 200-400 nm.

Preferably, the covering film has a thickness of 20 to 150 μm.

Preferably, the adhesive and the cover film composite film are both resistant to space ultraviolet radiation.

Preferably, in step S2, the covering film is a covering film with ultraviolet light transmittance, and the covering film includes at least one of ethylene-tetrafluoroethylene copolymer film, ethylene-chlorotrifluoroethylene copolymer film, perfluoroethylene propylene copolymer film, polyvinylidene fluoride film, polyvinyl fluoride film, tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer film;

The second aspect of the present invention protects an application of the packaging method described in the first aspect, wherein the packaging method is used to package a spatial solar cell array.

The beneficial technical effects of the present invention are:

The present invention reduces the weight of the battery by using flexible packaging materials such as ethylene-tetrafluoroethylene copolymer, ethylene-trifluorochloroethylene copolymer, perfluoroethylene-propylene copolymer, polyvinylidene fluoride, polyvinyl fluoride, tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer, etc., and is not easy to break when the wing is working and unfolding. At the same time, these films have ultraviolet transmittance, and are used in conjunction with adhesives with ultraviolet transmittance, so that ultraviolet light can be absorbed by the battery cell through the packaging material, increasing the photon utilization rate and obtaining a higher photoelectric conversion efficiency. At the same time, the packaging film and adhesive used can both transmit ultraviolet light and have strong ultraviolet radiation resistance, and still have a high light transmittance under long-term ultraviolet radiation.

The packaging materials used in the present invention, namely the covering film and the adhesive, have ultra-high transmittance in the 200-1300nm band and can be widely used in the packaging of different types of space solar cells, such as gallium arsenide solar cells, perovskite solar cells, crystalline silicon solar cells, crystalline silicon-perovskite tandem solar cells, perovskite-perovskite tandem solar cells, and copper indium gallium selenide-perovskite tandem solar cells; in particular, they can be used for the packaging of solar cells with different band gaps without significantly affecting their photoelectric conversion efficiency.

The packaging method of the present invention is simple, easy to implement and low in cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the cross-sectional structure of a packaged space solar cell array according to Example 1 of the present invention.

FIG. 2 is a transmittance curve of the ETFE used in Example 1 of the present invention and the glass cover in Comparative Example 1.

FIG. 3 is a transmittance curve of the UV-resistant adhesive and the common space adhesive used in Example 1 of the present invention.

FIG. 4 is a transmittance curve of the UV-transmitting adhesive/ETFE composite film at different UV irradiation times.

FIG5 is a transmittance curve of a common space silica gel/glass cover composite film at different UV irradiation times.

DETAILED DESCRIPTION

The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

The first aspect of the present invention provides a method for packaging a space solar cell array resistant to ultraviolet radiation. The packaging method can be used for packaging a space solar cell array. The space solar cell array structure resistant to ultraviolet radiation includes a substrate, an adhesive, a solar cell array to be packaged and a covering film.

In some embodiments of the present invention, the packaging method comprises the following steps:

S1: Adhesive is applied to the surface of the solar cell treated in step S1, and the surface of the substrate is covered on the surface of the adhesive (silicone gel), and thermally cured to obtain a solar cell with a substrate on the back.

S2: Covering the surface of the adhesive with a surface covering film, and thermally curing the film to obtain a packaged solar cell.

In some embodiments of the present invention, the solar cell array to be encapsulated includes at least one of a crystalline silicon solar cell array, a perovskite solar cell array, a gallium arsenide solar cell array, a copper indium gallium selenide solar cell array, a crystalline silicon-perovskite tandem solar cell array, and a copper indium gallium selenide-perovskite tandem solar cell array.

It can be understood that, in the present invention, the solar cell array to be packaged is a solar cell array obtained by welding two or more solar cell sheets;

It is understandable that the method that can realize the packaging of solar cell arrays can also realize the packaging of single solar cells. Therefore, the solar cell array to be packaged in the present invention can also be replaced by solar cells to realize the packaging of single solar cells.

In some embodiments of the present invention, the back side of the solar cell refers to the non-illuminated side, and the front side refers to the illuminated side.

In some embodiments of the present invention, in step S1, the substrate includes a rigid substrate, a semi-rigid substrate or a flexible substrate.

In some embodiments of the present invention, in steps S1 and S2, the adhesive is silicone resin. Preferably, the adhesive is silicone rubber that is resistant to ultraviolet radiation and transparent to ultraviolet light, and the light transmittance of the adhesive is >93%.

In some embodiments of the present invention, in steps S1 and S2, the adhesive is resistant to temperature changes between -100°C and 100°C, resistant to ultraviolet radiation, and has high ultraviolet light transmittance.

In some embodiments of the present invention, in steps S2 and S3, the coating thickness of the adhesive is 10 to 200 μm, including but not limited to 10 μm, 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, and 200 μm.

In some embodiments of the present invention, in steps S1 and S2, the thermal curing process is: first, keep the temperature at 50-60°C for 20-90 minutes, then heat to 90-100°C, keep the temperature for 20-90 minutes, and finally heat to 120-180°C, keep the temperature for 20-90 minutes.

In some embodiments of the present invention, in step S3, the light transmittance of the covering film is >93%. Preferably, the covering film is a thin film that is resistant to ultraviolet radiation and transparent to ultraviolet rays, and has a thickness of 20 to 150 μm, including but not limited to 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, and 150 μm.

In some embodiments of the present invention, in step S3, the covering film is a covering film with ultraviolet light transmittance, and the covering film includes at least one of ethylene-tetrafluoroethylene copolymer (ETFE) film, ethylene-chlorotrifluoroethylene copolymer (ECTFE) film, perfluoroethylene propylene copolymer (FEP) film, polyvinylidene fluoride (PVDF) film, polyvinyl fluoride (PVF) film, tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer (PFA) film;

It is understood that the coating in the present invention includes one or more of brush coating and scraping coating. The adhesive is preferably applied by scraping.

It is understandable that the solar cell of the present invention can utilize light in the ultraviolet band, so that the efficiency of the cell after packaging will not be substantially reduced. The covering film and adhesive used in the packaging method still have a high light transmittance after long-term ultraviolet irradiation.

It is understandable that the packaging method of the present invention can be better used for packaging solar cells with different band gaps than the existing packaging method, because the packaging material used in the packaging method of the present invention can transmit ultraviolet light and has a high transmittance in the solar cell absorption band of 200-1300nm. In addition, the packaging glue and packaging film used can still maintain a high transmittance under ultraviolet light irradiation, avoiding the power drop of conventionally packaged solar cell arrays during service due to changes in the transmittance of the packaging material.

The second aspect of the present invention provides an application of the packaging method described in the first aspect, that is, the packaging method is used to package a spatial solar cell array.

The present invention will be further described below by way of examples and the like.

Example 1

The packaging method of a space solar cell array resistant to ultraviolet radiation comprises the following steps:

S1: Battery array backside packaging

S1-1 selects crystalline silicon cells with good performance and welds them to make crystalline silicon solar cell arrays for subsequent packaging.

S1-2 Place the weighed adhesive in a homogenizer and mix evenly for use; wherein the adhesive is silicone rubber, the light transmittance of 200-1300nm is 94%, and it can withstand temperature changes of -100℃ to 100℃.

S1-3: Apply adhesive uniformly on the surface of the solar cell array, with the thickness controlled at about 120μm; then cover the surface of the substrate on the surface of the adhesive, i.e. the back of the cell; heat and cure it to obtain a solar cell array with a substrate on the back. The thermal curing process is: first heat at a low temperature of 50°C for 20 minutes, then increase the temperature to 100°C and heat for 20 minutes, and finally increase the temperature to 150°C and heat for 30 minutes to fully cure it.

S2: Encapsulating the front side of the solar cell array with the substrate on the back side, the specific method is as follows:

The ETFE surface covering film is cut into a suitable size, and the thickness of the ETFE film is 30 μm.

Pre-coat the front of the solar cell array with a thickness of about 120μm; cover the surface of the silicone adhesive with an ETFE film and heat and cure it. Specifically, first heat it at a low temperature of 50℃ for 20 minutes, then increase the temperature to 100℃ and heat it for 20 minutes, and finally increase the temperature to 150℃ and heat it for 30 minutes to fully cure it, thus obtaining a packaged space solar cell array.

Example 2

The packaging method of a space solar cell array resistant to ultraviolet radiation comprises the following steps:

S1: Solar cell array backside encapsulation

S1-1 selects GaAs cells with good performance and welds them to make GaAs solar cell arrays for subsequent packaging;

S1-2 Place the weighed adhesive in a homogenizer and mix evenly for standby use; wherein the adhesive is silicone rubber, the light transmittance of 200-1300nm is 94%, and it can withstand temperature changes of -100℃ to 100℃;

S1-3: Apply adhesive evenly on the surface of the solar cell array, with a thickness of about 120μm, and then cover the surface of the substrate on the surface of the adhesive, i.e. the back of the cell array; then heat it to cure the adhesive, and obtain a solar cell array with a substrate on the back. The thermal curing process is: first heat at a low temperature of 50℃ for 20min, then increase the temperature to 100℃ and heat for 20min, and finally increase the temperature to 150℃ and heat for 30min to fully cure it.

S2: Encapsulating the front side of the solar cell array with the substrate on the back side, the specific method is as follows:

Cutting an ETFE surface covering film of suitable size, the thickness of the ETFE film is 30 μm, and covering the surface of the silica gel with the ETFE film;

The glue-coated solar cell array is heated and cured. First, it is heated at a low temperature of 50° C. for 20 minutes, then the temperature is raised to 100° C. for 20 minutes, and finally the temperature is raised to 150° C. for 30 minutes to completely cure it, thereby obtaining a packaged space solar cell array.

Example 3

The packaging method of a space solar cell array resistant to ultraviolet radiation comprises the following steps:

S1: Solar cell array backside encapsulation

S1-1 prepare adhesive silica gel, the specific method is the same as Example 1, put the weighed adhesive in a homogenizer and mix evenly;

S1-2: Apply adhesive evenly on the surface of the solar cell array, with a thickness of about 120μm; then place a substrate cover on the adhesive surface, i.e., the back of the cell; then heat it to cure the adhesive, and obtain a solar cell array with a substrate on the back. The thermal curing process is: first heat at a low temperature of 50°C for 20 minutes, then increase the temperature to 100°C for 20 minutes, and finally increase the temperature to 150°C for 30 minutes to fully cure it.

S2: Encapsulating the front side of the solar cell array with the substrate on the back side, the specific method is as follows:

Pre-coat the front of the solar cell array with a thickness of about 120μm; cover the surface of the silicone adhesive with an ECTFE film, and heat it to solidify the front adhesive. First, heat it at a low temperature of 50℃ for 20 minutes, then increase the temperature to 100℃ for 20 minutes, and finally increase the temperature to 150℃ for 30 minutes to fully solidify it, thus obtaining a packaged space solar cell array.

Comparative Example 1

Different from Example 1, the encapsulation uses common space adhesive, which is silicone rubber that can filter UVC band (wavelength 200-280nm) ultraviolet light and can be cured directly in the air without heating. The common adhesive and glass cover used can resist electron and proton radiation, but the adhesive is easily degraded and yellowed under long-term ultraviolet light.

The specific packaging process is:

S1: Screen out crystalline silicon cells with good performance, weld them, and make solar cell arrays for subsequent packaging.

S2: Weigh the common space adhesive silica gel and mix it evenly in a homogenizer; then evenly apply the common space adhesive on the back surface of the battery, and the thickness is also controlled at about 120μm; place the substrate cover on the adhesive surface, that is, the back of the battery array, and place it in a constant temperature and humidity atmosphere for 24 hours, and cure it at room temperature.

S3: The front side of the battery is then packaged. Similar to the above operation, 120 μm of adhesive is scraped on the surface of the battery array. A cerium-doped glass cover is covered on the adhesive. The thickness of the glass cover is 120 μm. The battery array is placed in a constant temperature and humidity storage cabinet for 24 hours for room temperature curing.

Test example:

The performance test of the packaging materials used in the embodiments and comparative examples is shown in Figures 2-5. Figure 2 is the transmittance curve of the ultraviolet-transmissive ETFE used in Example 1 of the present invention and the glass cover in Comparative Example 1; it can be seen from the figure that the ETFE film has a high transmittance in the ultraviolet band of 200-400nm, indicating that ETFE can transmit ultraviolet light. The glass cover can transmit ultraviolet light in the band of 320-400nm, and in the visible light band, the average transmittance of the ETFE film is higher than that of the glass cover, indicating that ETFE also has good light transmittance in the visible light band.

FIG3 is a transmittance curve of the UV-resistant adhesive and the common space adhesive used in Example 1 of the present invention; the UV-resistant adhesive has a high transmittance in the entire UV band of 200-400nm, and the common space adhesive can absorb light less than 280nm.

Referring to the conditions of Example 1, the UV-resistant adhesive of Example 1 is coated on the surface of ETFE and thermally cured to obtain a composite film; similarly, the common space adhesive of Comparative Example 1 is coated on the surface of the glass cover and cured at room temperature to obtain an adhesive/glass composite layer. The transmittance of the two composite layers before and after 201 hours of irradiation is tested. Figure 4 is a transmittance curve of the UV-resistant adhesive/ETFE composite film before and after irradiation with an intensity of 12.839W/ ^m2 . Figure 5 is a transmittance curve of the common space adhesive/glass composite layer before and after irradiation with an intensity of 12.839W/ ^m2 . During the test, light is incident from the ETFE or glass surface. It can be seen from the figure that after 201 hours of irradiation, obvious yellowing phenomenon is observed in the common space adhesive/glass composite layer, and the transmittance between 320nm-500nm decreases rapidly, which is the strong spectral response area of the solar cell, and thus has a greater impact on the short-circuit current of the bottom cell. However, no obvious yellowing phenomenon was observed for the UV-resistant adhesive/ETFE composite film after irradiation, and the transmittance decreased slightly, which indicates that the UV-resistant adhesive/ETFE composite film is more resistant to UV radiation.

The packaging method of the present invention allows ultraviolet light in space to be transmitted and absorbed by the battery cell, thereby increasing the photon utilization rate. At the same time, the packaging material has ultraviolet radiation resistance, thereby improving the power output stability of the battery array in the space environment.

The above is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims (10)

1. A method for packaging a solar cell array that is resistant to ultraviolet radiation, characterized in that the packaging method comprises the following steps: S1: coating an adhesive on the surface of the solar cell array to be packaged, and placing the surface of the substrate on the surface of the adhesive, and thermally curing the adhesive to obtain a solar cell array with the substrate on the back; S2: in step S1, an adhesive is applied to the front side of the solar cell array including the substrate on the back side, a covering film is placed on the surface of the adhesive, and thermally cured to obtain a packaged solar cell array. 2. The packaging method according to claim 1 is characterized in that in step S1, the solar cell array to be packaged includes at least one of a crystalline silicon solar cell array, a perovskite solar cell array, a gallium arsenide solar cell array, a copper indium gallium selenide solar cell array, a crystalline silicon-perovskite stacked solar cell array, and a copper indium gallium selenide-perovskite stacked solar cell array. 3. The packaging method according to claim 1 is characterized in that in steps S1 and S2, the adhesive is silicone resin, preferably, the adhesive is silicone rubber that is transparent to ultraviolet light and resistant to ultraviolet radiation, and the light transmittance of the adhesive is >93%. 4. The packaging method according to claim 1, characterized in that in steps S1 and S2, the adhesive is resistant to temperature changes of -100°C to 100°C. 5 . The packaging method according to claim 1 , characterized in that in steps S1 and S2 , the coating thickness of the adhesive is 10 to 200 μm. 6. The packaging method according to claim 1 is characterized in that in steps S1 and S2, the thermal curing process is: first, keep the temperature at 50-60°C for 20-90 minutes, then heat it to 90-100°C, keep it for 20-90 minutes, and finally heat it to 120-180°C, keep it for 20-90 minutes. 7 . The packaging method according to claim 1 , characterized in that, in step S2 , the light transmittance of the covering film is greater than 93%, and preferably, the thickness of the covering film is 20 to 150 μm. 8 . The packaging method according to claim 1 , wherein the adhesive and the cover film composite film are both resistant to space ultraviolet radiation. 9. The packaging method according to claim 1 is characterized in that in step S2, the covering film is a covering film with ultraviolet light transmittance, and the covering film includes at least one of ethylene-tetrafluoroethylene copolymer film, ethylene-chlorotrifluoroethylene copolymer film, perfluoroethylene propylene copolymer film, polyvinyl fluoride film, polyvinylidene fluoride film, polyvinyl fluoride film, and tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer film. 10. An application of the packaging method according to any one of claims 1 to 9, characterized in that the packaging method is used to package a spatial solar cell array.