A space solar cell array and a method of manufacturing the same

Abstract

The application discloses a kind of space solar cell array and its manufacturing method, it is related to solar cell array technical field.The application includes the following process: step 1 from bottom to top in turn on substrate lays backside flexible buffer film material, metal interconnection band series solar cell, connects metal interconnection band series solar cell, bypass diode, isolation diode and wire, completes electronic circuit laying and connection, obtains solar cell array module;Step 2 in turn places front transparent buffer film material, front transparent encapsulation material on solar cell array module, then is fixed using pressing mechanism, obtains space solar cell array.The application cancels the direct bonding between solar cell and substrate, front encapsulation material, avoids the stress concentration and fracture risk caused by the mismatch of thermal expansion coefficient between materials, thereby significantly improves the structural reliability and service life of solar cell array in the environment of temperature change.

Description

Technical Field

[0001] This invention relates to the field of solar cell array technology, specifically a space solar cell array and its fabrication method. Background Technology

[0002] The development of satellite internet not only helps ensure independent controllability in the information and communication field and strengthens information security barriers, but also empowers multiple fields such as intelligent manufacturing, telemedicine, and smart agriculture. Currently, low-Earth orbit satellite constellations are evolving towards "high-density deployment, high-computing-power integration, and low-latency response," and the resulting payload energy demands are leaping from the hundreds of watts to the kilowatts, tens of thousands of watts, and even megawatts. As the only energy harvesting method in the space energy system, solar cell arrays directly determine the capacity, volume, weight, and lifespan of satellite payloads, and are currently in a critical stage of technological breakthroughs and large-scale application.

[0003] Currently, space-based solar arrays primarily utilize gallium arsenide (GaAs) solar cells. The process involves bonding GaAs solar cells to a cover glass sheet using silicone to create a tandem array, then securing the tandem cells to a substrate using silicone rubber, and finally connecting them via electronic circuitry to form the solar array. However, the space environment during on-orbit operation is extremely harsh, with temperature differences exceeding 200°C. The significant differences in thermal expansion coefficients between different materials lead to substantial thermal expansion and contraction during temperature cycling. Particularly concerning are the varying degrees of deformation between the substrate, solar cells, and metal interconnects. Since the solar cells are bonded and fixed to the substrate, this uneven deformation can cause internal stress concentration and mechanical fatigue, potentially leading to interconnect breakage, cell rupture, or even the failure of the entire solar array, threatening the safety of the entire satellite.

[0004] In response to the above problems, based on the inventor's many years of focused research experience in this field, it was decided to seek technical solutions to address these technical issues. Summary of the Invention

[0005] The purpose of this invention is to provide a space solar cell array and its manufacturing method, which can effectively improve the problem of stress concentration, material mechanical fatigue, and even material fracture caused by the mismatch of thermal expansion coefficients between the solar cell array substrate material and the solar cell and metal interconnects, thereby improving the reliability and service life of the solar cell array and the entire satellite.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A space solar cell array, wherein the space solar cell array is a multi-layer structure, comprising, from bottom to top, a substrate, a flexible buffer film material on the back, a solar cell array module, a transparent buffer film material on the front, and a transparent encapsulation material on the front, and the multi-layer structure is fixed by a clamping mechanism;

[0008] The substrate is one of an aluminum honeycomb rigid substrate, a composite flexible substrate, or a polyimide single-layer flexible substrate;

[0009] The flexible buffer film material on the back and the transparent buffer film material on the front are one of space-grade silicone rubber and polyolefin elastomer film.

[0010] The front transparent encapsulation material is one of glass, transparent polyimide, or ethylene-tetrafluoroethylene copolymer.

[0011] Preferably, the solar cell array module includes solar cells connected in series with metal interconnects, bypass diodes, isolation diodes, and wires, etc., and the solar cells are one of gallium arsenide solar cells, crystalline silicon solar cells, and perovskite solar cells; the clamping mechanism is distributed around and inside the solar cell array, and is one of mechanical fixing with screws and adhesive fixing.

[0012] Preferably, the thickness of the back flexible buffer film material is 50~500μm; the thickness of the front transparent buffer film material is 50~500μm; and the thickness of the front transparent encapsulation material is 5~500μm.

[0013] Preferably, the preparation steps of the space-grade silicone rubber are as follows:

[0014] Weigh out low-phenyl silicone rubber base, methyltriethoxysilane, n-hexane, hydroxyl polyhedral oligomeric silsesquioxane, and modified boron nitride filler, mix them, and stir at 1950-2050 r / min for 20-25 min at 35-45℃ to obtain a premix. Add dibutyltin dilaurate to the premix, raise the temperature to 55-65℃, and stir at 1950-2050 r / min for 20-25 min to obtain a slurry. Pour the slurry onto a clean glass plate and spread it to obtain a wet film. Crosslink and cure the glass plate with the wet film at 70-75℃ for 1.5-2.5 h to obtain space-grade silicone rubber.

[0015] Preferably, the mass ratio of the low-phenyl silicone rubber base, methyltriethoxysilane, n-hexane, hydroxyl polyhedral oligomeric silsesquioxane, modified boron nitride filler, and dibutyltin dilaurate is 25:1.5:10:5:11:1.

[0016] Preferably, the preparation steps of the hydroxyl polyhedral oligomeric silsesquioxane are as follows:

[0017] Ammoniated trialkoxysilane, triethylamine, chloropropanol, and toluene were mixed and reacted at 45–55 °C for 4–6 h. The mixture was then separated, and the liquid component was distilled to obtain a hydroxyl polyhedral oligomeric silsesquioxane precursor. The hydroxyl polyhedral oligomeric silsesquioxane precursor, trifluoromethanesulfonic acid, and distilled water were mixed and reacted with stirring at 20–25 °C for 1–3 h. The mixture was then distilled under reduced pressure at 70 °C for 1–3 h. After cooling to 20–25 °C, the mixture was washed with acetone, filtered, and dried under vacuum to obtain the hydroxyl polyhedral oligomeric silsesquioxane.

[0018] Preferably, the mass ratio of aminopropyltrialkoxysilane, triethylamine, chloropropanol and toluene is 18:10:9.4:80; and the mass ratio of hydroxyl polyhedral oligomeric silsesquioxane precursor, trifluoromethanesulfonic acid and distilled water is 4.38:4.5:60.

[0019] Preferably, the preparation steps of the modified boron nitride filler are as follows:

[0020] S1: Aluminum chloride hexahydrate, anhydrous ethanol, and deionized water were mixed to prepare an aluminum chloride solution with a concentration of 0.5 mol / L. Boron nitride nanosheets were added to obtain a mixed solution. A 1.8 mol / L ammonia solution was added dropwise to the mixed solution, stirred for 10-15 min, centrifuged at 2950-3050 r / min, washed and centrifuged multiple times with anhydrous ethanol, and dried at 55-65℃ for 9-11 h to obtain the precursor aluminum hydroxide-boron nitride nanosheets.

[0021] S2: The precursor aluminum hydroxide-boron nitride nanosheets were calcined at a temperature gradient of 5℃ / min to obtain the modified boron nitride filler.

[0022] Preferably, the mass ratio of aluminum chloride hexahydrate, anhydrous ethanol, deionized water, and boron nitride nanosheets in S1 is 6.05:237.5:12.5:5.5; the gradient heating conditions in S2 are to hold at 500℃, 700℃, 900℃, and 1200℃ for 1~1.5h each.

[0023] This invention also provides a method for fabricating a space solar cell array, comprising the following steps:

[0024] Step 1: From bottom to top, lay the flexible buffer film material on the back side, the solar cells connected in series with the metal interconnect strip on the substrate, connect the solar cells connected in series with the metal interconnect strip, the bypass diode, the isolation diode and the wire to complete the electronic circuit laying and connection, and obtain the solar cell array module.

[0025] Step 2: Place the front transparent buffer film material and the front transparent encapsulation material on the solar cell array module in sequence, and then fix them with a clamping mechanism to obtain the space solar cell array.

[0026] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0027] This invention first lays a flexible, cured silicone rubber layer on a substrate, then places the solar cells on the silicone rubber layer and connects them to the circuitry. Next, a transparent, cured silicone rubber layer is covered over the surface of the solar cells, and then glass or other transparent encapsulation material is placed on top. Finally, the upper transparent encapsulation material is mechanically or adhesively pressed and fixed to the substrate. In this structure, the silicone rubber serves only as a flexible buffer and physical support medium, rather than for adhesive fixation. This solution eliminates the direct bonding between the solar cells and the substrate and the front encapsulation material, avoiding stress concentration and fracture risks caused by mismatched thermal expansion coefficients between materials, thereby significantly improving the structural reliability and lifespan of the solar cell array in environments with drastic temperature changes. Simultaneously, the design of using a single piece of front encapsulation material to fully cover the substrate, replacing the traditional independent encapsulation of individual cells, simplifies the assembly process, improves production efficiency, is more suitable for mass production, and helps reduce overall costs.

[0028] The methyltriethoxysilane used in this invention undergoes condensation crosslinking with the silanol groups of a low-phenyl silicone rubber base under the catalysis of dibutyltin dilaurate. Simultaneously, a hydroxyl polyhedral oligomeric silsesquioxane covalently integrates into this crosslinking network through its multiple silanol groups, forming an organic-inorganic hybrid structure that possesses both flexibility and rigidity. For the modified boron nitride filler, firstly through Al… 3+ Aluminum hydroxide is uniformly deposited on the surface of boron nitride nanosheets through a precipitation reaction with ammonia. This is followed by segmented calcination and dehydration to transform it into a dense alumina coating. This chemical modification not only retains the high thermal conductivity and electrical insulation of boron nitride but also improves the interfacial incompatibility between the filler and the organic substrate by forming hydrogen bonds or covalent bonds between the hydroxyl groups on the alumina surface and the silicone rubber matrix. Hydroxyl polyhedral oligomeric silsesquioxanes, acting as rigid nanonodes, are uniformly dispersed in the cross-linked network, improving the film's modulus and resistance to proton oxygen attack. Furthermore, their cage-like structure prevents light scattering, maintaining the film's transparency. Meanwhile, the modified boron nitride filler avoids aggregation through surface bonding, allowing the buffer layer to rapidly dissipate heat generated by the solar cell. The organic-inorganic hybrid framework provided by hydroxyl polyhedral oligomeric silsesquioxane and the thermally conductive network of modified boron nitride filler interweave in space. Combined with the flexibility of low-phenyl silicone rubber, they synergistically achieve antigenic oxygen / ultraviolet irradiation and high light transmittance, thereby ensuring the long-term reliable operation of space solar cell arrays under environments such as temperature alternation and atomic oxygen irradiation. Attached Figure Description

[0029] Figure 1This is a cross-sectional view of the solar cell array in Embodiment 1 of the present invention;

[0030] Figure 2 This is a top view of the solar cell array in Embodiment 1 of the present invention;

[0031] Figure 3 This is a cross-sectional view of the solar cell array in Embodiment 2 of the present invention;

[0032] Figure 4 This is a top view of the solar cell array in Embodiment 2 of the present invention;

[0033] The numbers in the diagram are: 1-substrate; 2-back flexible buffer film; 3-solar cell; 4-metal interconnect strip; 5-front transparent flexible buffer film; 6-front encapsulation material; 701-fixing screw; 702-fixing adhesive. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments 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.

[0035] It should be noted that there are no special restrictions on the suppliers of all raw materials involved in this invention. Exemplary examples include: substrate: aluminum honeycomb rigid substrate; solar cell: monocrystalline silicon solar cell; back flexible buffer film material: cured space-grade silicone rubber with a thickness of 100 μm and a glass transition temperature below -100°C; front transparent flexible buffer film material: cured high-transparency space-grade silicone rubber with a thickness of 100 μm and a glass transition temperature below -100°C; front transparent encapsulation material: cover glass. Glass, 100μm thick; Adhesive: Silicone resin, solvent-based, transmittance >93%, resistant to temperature alternation from -100℃ to 100℃; Low-phenyl silicone rubber base: Spatial grade, phenyl content <30%; Dibutyltin dilaurate: purity 19%; Boron nitride nanosheets: particle size 100nm; Concentrated ammonia: mass concentration 28%; Methyltriethoxysilane, n-hexane, aminopropyltrialkoxysilane, triethylamine, chloropropanol, toluene, trifluoromethanesulfonic acid, acetone, aluminum chloride hexahydrate, and anhydrous ethanol are all analytical grade.

[0036] Example 1: A space solar cell array and its fabrication method, comprising the following steps:

[0037] Step 1: The overall size of the aluminum honeycomb rigid substrate is larger than the area where the solar cells and circuits are arranged. A 20mm gap is left between the edge of the substrate and the edge of the solar cells. Screw holes are reserved at the four corners of the substrate, 10mm from the edge. The flexible buffer film material on the back is a cured space-grade silicone rubber with the same size as the substrate and a thickness of 100μm.

[0038] Step 2: Lay the flexible buffer film material on the back side onto the rigid aluminum honeycomb substrate and make it flat and adhered; place the solar cells connected in series with the metal interconnect strip on the flexible buffer film material on the back side, and connect the solar cells connected in series with the metal interconnect strip, bypass diodes, isolation diodes and wires to complete the laying and connection of the electronic circuit and obtain the solar cell array module.

[0039] Step 3: Use a 100μm thick cured high-transparency space-grade silicone rubber as the front transparent flexible buffer film material, with the same size as the back flexible buffer film material, and cover the solar cell array module with the front transparent buffer film material.

[0040] Step 4: Use glass as the front transparent encapsulation material, pre-drill screw holes at its four corners and align them with the screw holes on the substrate, and place the front transparent encapsulation material glass on the front transparent buffer film material.

[0041] Step 5: Secure the front-side encapsulation glass to the aluminum honeycomb rigid substrate using fixing screws to obtain the space solar cell array.

[0042] Example 2: A space solar cell array and its fabrication method, comprising the following steps:

[0043] Step 1: The overall size of the aluminum honeycomb rigid substrate is larger than the area where the solar cells and circuits are arranged, and a 20mm gap is left between the edge of the substrate and the edge of the solar cells; the flexible buffer film material on the back is a cured space-grade silicone rubber, which is 10mm smaller than the substrate and has a thickness of 100μm.

[0044] Step 2: Lay the flexible buffer film material on the back side onto the rigid aluminum honeycomb substrate and make it flat and adhered; place the solar cells connected in series with the metal interconnect strip on the flexible buffer film material on the back side, and connect the solar cells connected in series with the metal interconnect strip, bypass diodes, isolation diodes and wires to complete the laying and connection of the electronic circuit and obtain the solar cell array module.

[0045] Step 3: Use a 100μm thick cured high-transparency space-grade silicone rubber as the front transparent flexible buffer film material, with the same size as the back flexible buffer film material, and cover the solar cell array module with the front transparent buffer film material.

[0046] Step 4: Place the front transparent encapsulation material glass on the front transparent buffer film material, 6mm away from the outer edge of the buffer material, apply adhesive, press and fix it to obtain the space solar cell array.

[0047] Example 3: A space solar cell array and its fabrication method, comprising the following steps:

[0048] Step 1: The overall size of the aluminum honeycomb rigid substrate is larger than the area where the solar cells and circuits are arranged. A 20mm gap is left between the edge of the substrate and the edge of the solar cells. Screw holes are reserved at the four corners of the substrate, 10mm from the edge. The flexible buffer film material on the back is a cured space-grade silicone rubber with the same size as the substrate and a thickness of 100μm.

[0049] Step 2: Lay the flexible buffer film material on the back side onto the rigid aluminum honeycomb substrate and make it flat and adhered; place the solar cells connected in series with the metal interconnect strip on the flexible buffer film material on the back side, and connect the solar cells connected in series with the metal interconnect strip, bypass diodes, isolation diodes and wires to complete the laying and connection of the electronic circuit and obtain the solar cell array module.

[0050] Step 3: Use a 100μm thick cured high-transparency space-grade silicone rubber as the front transparent flexible buffer film material, with the same size as the back flexible buffer film material, and cover the solar cell array module with the front transparent buffer film material.

[0051] Step 4: Use glass as the front transparent encapsulation material, pre-drill screw holes at its four corners and align them with the screw holes on the substrate, and place the front transparent encapsulation material glass on the front transparent buffer film material.

[0052] Step 5: Secure the front-side encapsulation glass to the aluminum honeycomb rigid substrate using fixing screws to obtain the space solar cell array;

[0053] The preparation steps of the cured space-grade silicone rubber are as follows:

[0054] Weigh out 25g of low-phenyl silicone rubber base, 1.5g of methyltriethoxysilane, 10g of n-hexane, 5g of hydroxyl polyhedral oligomeric silsesquioxane, and 11g of modified boron nitride filler, and mix them. Stir at 1950r / min for 20min at 35℃ to obtain a premix. Add 1g of dibutyltin dilaurate to the premix, raise the temperature to 55℃, and stir at 1950r / min for 20min to obtain a slurry. Pour the slurry onto a clean glass plate and slowly spread it in one direction using a single-blade applicator to spread the slurry into a wet film with uniform thickness and a smooth surface. Place the glass plate with the wet film in a 70℃ oven for heat treatment for 1.5h to complete cross-linking and curing, and obtain cured space-grade silicone rubber.

[0055] The preparation steps of the hydroxyl polyhedral oligomeric silsesquioxane are as follows:

[0056] 18g of aminopropyltrialkoxysilane, 10g of triethylamine, 9.4g of chloropropanol and 80g of toluene were mixed and reacted at 45°C for 4h. After the reaction was completed, solid impurities were separated and removed, and the liquid component was distilled to remove toluene and unreacted raw materials to obtain a hydroxyl polyhedral oligomeric silsesquioxane precursor. 4.38g of the hydroxyl polyhedral oligomeric silsesquioxane precursor was placed in a single-necked flask, and 4.5g of trifluoromethanesulfonic acid catalyst and 60g of distilled water were added sequentially. The mixture was stirred and reacted at 20°C for 1h. The reaction solution was distilled under reduced pressure at 70°C for 1h to remove water. After cooling to 20°C, 5mL of acetone was added for washing, and the mixture was filtered and dried under vacuum to obtain the hydroxyl polyhedral oligomeric silsesquioxane.

[0057] The preparation steps of the modified boron nitride filler are as follows:

[0058] S1: Mix 6.05g aluminum chloride hexahydrate, 237.5mL anhydrous ethanol and 12.5mL deionized water, stir thoroughly to prepare an aluminum chloride solution with a concentration of 0.5mol / L, add 5.5g boron nitride nanosheets to obtain a mixed solution; slowly add 50mL of ammonia solution with a concentration of 1.8mol / L, prepared by mixing concentrated ammonia water and anhydrous ethanol at a volume ratio of 13:87, to the mixed solution. After the addition is complete, continue stirring for 10min, centrifuge at 2950r / min, wash and centrifuge multiple times with anhydrous ethanol, dry in an oven at 55℃ for 9h to obtain the precursor aluminum hydroxide-boron nitride nanosheets;

[0059] S2: The precursor aluminum hydroxide-boron nitride nanosheets were placed in a tube furnace for programmed temperature calcination with a gradient heating rate of 5℃ / min, and held at 500℃, 700℃, 900℃ and 1200℃ for 1h each to obtain the modified boron nitride filler.

[0060] Example 4: A space solar cell array and its fabrication method, comprising the following steps:

[0061] Step 1: The overall size of the aluminum honeycomb rigid substrate is larger than the area where the solar cells and circuits are arranged. A 20mm gap is left between the edge of the substrate and the edge of the solar cells. Screw holes are reserved at the four corners of the substrate, 10mm from the edge. The flexible buffer film material on the back is a cured space-grade silicone rubber with the same size as the substrate and a thickness of 100μm.

[0062] Step 2: Lay the flexible buffer film material on the back side onto the rigid aluminum honeycomb substrate and make it flat and adhered; place the solar cells connected in series with the metal interconnect strip on the flexible buffer film material on the back side, and connect the solar cells connected in series with the metal interconnect strip, bypass diodes, isolation diodes and wires to complete the laying and connection of the electronic circuit and obtain the solar cell array module.

[0063] Step 3: Use a 100μm thick cured high-transparency space-grade silicone rubber as the front transparent flexible buffer film material, with the same size as the back flexible buffer film material, and cover the solar cell array module with the front transparent buffer film material.

[0064] Step 4: Use glass as the front transparent encapsulation material, pre-drill screw holes at its four corners and align them with the screw holes on the substrate, and place the front transparent encapsulation material glass on the front transparent buffer film material.

[0065] Step 5: Secure the front-side encapsulation glass to the aluminum honeycomb rigid substrate using fixing screws to obtain the space solar cell array;

[0066] The preparation steps of the cured space-grade silicone rubber are as follows:

[0067] Weigh out 50g of low-phenyl silicone rubber base, 3g of methyltriethoxysilane, 20g of n-hexane, 10g of hydroxyl polyhedral oligomeric silsesquioxane, and 22g of modified boron nitride filler, and mix them. Stir at 2000r / min for 23min at 40℃ to obtain a premix. Add 2g of dibutyltin dilaurate to the premix, raise the temperature to 60℃, and stir at 2000r / min for 23min to obtain a slurry. Pour the slurry onto a clean glass plate and slowly spread it in one direction using a single-blade applicator to spread the slurry into a wet film with uniform thickness and a smooth surface. Place the glass plate with the wet film in a 73℃ oven for heat treatment for 2h to complete cross-linking and curing, and obtain cured space-grade silicone rubber.

[0068] The preparation steps of the hydroxyl polyhedral oligomeric silsesquioxane are as follows:

[0069] 36g of aminopropyltrialkoxysilane, 20g of triethylamine, 18.8g of chloropropanol and 160g of toluene were mixed and reacted at 50℃ for 5h. After the reaction was completed, solid impurities were separated and removed, and the liquid component was distilled to remove toluene and unreacted raw materials to obtain a hydroxyl polyhedral oligomeric silsesquioxane precursor. 8.76g of the hydroxyl polyhedral oligomeric silsesquioxane precursor was placed in a single-necked flask, and 9g of trifluoromethanesulfonic acid catalyst and 120g of distilled water were added sequentially. The mixture was stirred and reacted at 23℃ for 2h. The reaction solution was distilled under reduced pressure at 70℃ for 2h to remove water. After cooling to 23℃, 10mL of acetone was added for washing, and the mixture was filtered and dried under vacuum to obtain the hydroxyl polyhedral oligomeric silsesquioxane.

[0070] The preparation steps of the modified boron nitride filler are as follows:

[0071] S1: Mix 12.1g of aluminum chloride hexahydrate, 475mL of anhydrous ethanol and 25mL of deionized water, stir thoroughly to prepare an aluminum chloride solution with a concentration of 0.5mol / L, add 11g of boron nitride nanosheets to obtain a mixed solution; slowly add 100mL of ammonia solution with a concentration of 1.8mol / L, prepared by mixing concentrated ammonia water and anhydrous ethanol at a volume ratio of 13:87, to the mixed solution. After the addition is complete, continue stirring for 13min, centrifuge at 3000r / min, wash and centrifuge repeatedly with anhydrous ethanol, dry in a 60℃ oven for 10h after washing to obtain the precursor aluminum hydroxide-boron nitride nanosheets;

[0072] S2: The precursor aluminum hydroxide-boron nitride nanosheets were placed in a tube furnace for programmed temperature calcination with a heating rate of 5℃ / min and held at 500℃, 700℃, 900℃ and 1200℃ for 1.3h each to obtain the modified boron nitride filler.

[0073] Example 5: A space solar cell array and its fabrication method, comprising the following steps:

[0074] Step 1: The overall size of the aluminum honeycomb rigid substrate is larger than the area where the solar cells and circuits are arranged. A 20mm gap is left between the edge of the substrate and the edge of the solar cells. Screw holes are reserved at the four corners of the substrate, 10mm from the edge. The flexible buffer film material on the back is a cured space-grade silicone rubber with the same size as the substrate and a thickness of 100μm.

[0075] Step 2: Lay the flexible buffer film material on the back side onto the rigid aluminum honeycomb substrate and make it flat and adhered; place the solar cells connected in series with the metal interconnect strip on the flexible buffer film material on the back side, and connect the solar cells connected in series with the metal interconnect strip, bypass diodes, isolation diodes and wires to complete the laying and connection of the electronic circuit and obtain the solar cell array module.

[0076] Step 3: Use a 100μm thick cured high-transparency space-grade silicone rubber as the front transparent flexible buffer film material, with the same size as the back flexible buffer film material, and cover the solar cell array module with the front transparent buffer film material.

[0077] Step 4: Use glass as the front transparent encapsulation material, pre-drill screw holes at its four corners and align them with the screw holes on the substrate, and place the front transparent encapsulation material glass on the front transparent buffer film material.

[0078] Step 5: Secure the front-side encapsulation glass to the aluminum honeycomb rigid substrate using fixing screws to obtain the space solar cell array;

[0079] The preparation steps of the cured space-grade silicone rubber are as follows:

[0080] Weigh out 75g of low-phenyl silicone rubber base, 4.5g of methyltriethoxysilane, 30g of n-hexane, 15g of hydroxyl polyhedral oligomeric silsesquioxane, and 33g of modified boron nitride filler, and mix them. Stir at 2050r / min for 25min at 45℃ to obtain a premix. Add 3g of dibutyltin dilaurate to the premix, raise the temperature to 65℃, and stir at 2050r / min for 25min to obtain a slurry. Pour the slurry onto a clean glass plate and slowly spread it in one direction using a single-blade applicator to spread the slurry into a wet film with uniform thickness and a smooth surface. Place the glass plate with the wet film in a 75℃ oven for heat treatment for 2.5h to complete cross-linking and curing, and obtain cured space-grade silicone rubber.

[0081] The preparation steps of the hydroxyl polyhedral oligomeric silsesquioxane are as follows:

[0082] 54g of aminopropyltrialkoxysilane, 30g of triethylamine, 28.2g of chloropropanol and 240g of toluene were mixed and reacted at 55℃ for 6h. After the reaction was completed, solid impurities were separated and removed, and the liquid component was distilled to remove toluene and unreacted raw materials to obtain a hydroxyl polyhedral oligomeric silsesquioxane precursor. 13.14g of the hydroxyl polyhedral oligomeric silsesquioxane precursor was placed in a single-necked flask, and 13.5g of trifluoromethanesulfonic acid catalyst and 180g of distilled water were added sequentially. The mixture was stirred and reacted at 25℃ for 3h. The reaction solution was distilled under reduced pressure at 70℃ for 3h to remove water. After cooling to 25℃, 15mL of acetone was added for washing, and the mixture was filtered and dried under vacuum to obtain the hydroxyl polyhedral oligomeric silsesquioxane.

[0083] The preparation steps of the modified boron nitride filler are as follows:

[0084] S1: Mix 18.15g aluminum chloride hexahydrate, 712.5mL anhydrous ethanol and 37.5mL deionized water, stir thoroughly to prepare an aluminum chloride solution with a concentration of 0.5mol / L, add 16.5g boron nitride nanosheets to obtain a mixed solution; slowly add 150mL of ammonia solution with a concentration of 1.8mol / L, prepared by mixing concentrated ammonia water and anhydrous ethanol at a volume ratio of 13:87, to the mixed solution. After the addition is complete, continue stirring for 15min, centrifuge at 3050r / min, wash and centrifuge multiple times with anhydrous ethanol, dry in a 65℃ oven for 11h after washing to obtain the precursor aluminum hydroxide-boron nitride nanosheets;

[0085] S2: The precursor aluminum hydroxide-boron nitride nanosheets were placed in a tube furnace for programmed temperature calcination with a heating rate of 5℃ / min and held at 500℃, 700℃, 900℃ and 1200℃ for 1.5h each to obtain the modified boron nitride filler.

[0086] Comparative Example 1: Compared with Example 5, no hydroxyl polyhedral oligomeric silsesquioxane was added, and the remaining steps were the same as in Example 5.

[0087] Comparative Example 2: Compared with Example 5, no modified boron nitride filler was added, and the remaining steps were the same as in Example 5.

[0088] Testing experiments: The properties of the cured space-grade silicone rubbers prepared in Examples 3-5 and Comparative Examples 1-2 were tested.

[0089] Thermal conductivity test: ASTM D5470-17(2024) was used as the reference standard. The sample size was a circular disc with a diameter of 25 mm and a thickness of 100 μm.

[0090] Atomic oxygen performance testing: The sample size was a circular disc with a diameter of 1 cm and a thickness of 80 μm. The cumulative flux of atomic oxygen was 1.2 × 10⁻⁶. 21 atoms / cm 2 The exposure time was 240 hours, and the mass loss of the test sample was measured.

[0091] The obtained data is shown in Table 1:

[0092] Table 1

[0093]

[0094] Conclusion: As shown in Table 1, the synergistic reinforcement system of hydroxyl polyhedral oligomeric silsesquioxane and modified boron nitride in Examples 3-5 significantly improved thermal conductivity, while exhibiting extremely low mass loss after atomic oxygen exposure. This confirms the effective construction of the organic-inorganic hybrid network and thermal conductivity pathway. After being subjected to high cumulative flux atomic oxygen irradiation, the mass loss of the samples in Examples 3-5 remained at a low level, demonstrating that the hybrid interface possesses high resistance to atomic oxygen erosion and can withstand long-term oxidative erosion and thermal stress impact in the space environment. Comparative Example 1 without hydroxyl polyhedral oligomeric silsesquioxane and Comparative Example 2 without modified boron nitride filler showed significantly reduced thermal conductivity and significantly increased atomic oxygen mass loss. This, in turn, confirms that the synergy between the anti-erosion cage-like framework provided by the hydroxyl polyhedral oligomeric silsesquioxane as a rigid nanonode and the highly efficient thermally conductive network formed by the modified boron nitride filler is a core element for achieving high thermal conductivity of the buffer film and long-term reliable operation in space.

[0095] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A space solar cell array, characterized in that: The space solar cell array is a multi-layer structure, which, from bottom to top, includes a substrate, a flexible buffer film material on the back, a solar cell array module, a transparent buffer film material on the front, and a transparent encapsulation material on the front. The multi-layer structure is fixed by a clamping mechanism. The substrate is one of an aluminum honeycomb rigid substrate, a composite flexible substrate, or a polyimide single-layer flexible substrate; The flexible buffer film material on the back and the transparent buffer film material on the front are one of space-grade silicone rubber and polyolefin elastomer film. The transparent encapsulation material on the front is one of glass, transparent polyimide, or ethylene-tetrafluoroethylene copolymer.

2. The space solar cell array according to claim 1, characterized in that: The solar cell array module includes solar cells connected in series with metal interconnects, bypass diodes, isolation diodes, and wires, etc. The solar cells are one of gallium arsenide solar cells, crystalline silicon solar cells, and perovskite solar cells; the clamping mechanism is distributed around and inside the solar cell array, and is one of mechanical fixing with screws and adhesive fixing.

3. A space solar cell array according to claim 1, characterized in that: The thickness of the flexible buffer film material on the back is 50~500μm; the thickness of the transparent buffer film material on the front is 50~500μm. The thickness of the transparent encapsulation material on the front is 5~500μm.

4. A space solar cell array according to claim 1, characterized in that: The preparation steps of the space-grade silicone rubber are as follows: Weigh out low-phenyl silicone rubber base, methyltriethoxysilane, n-hexane, hydroxyl polyhedral oligomeric silsesquioxane, and modified boron nitride filler, mix them, and stir at 1950-2050 r / min for 20-25 min at 35-45℃ to obtain a premix. Add dibutyltin dilaurate to the premix, raise the temperature to 55-65℃, and stir at 1950-2050 r / min for 20-25 min to obtain a slurry. Pour the slurry onto a clean glass plate and spread it to obtain a wet film. Crosslink and cure the glass plate with the wet film at 70-75℃ for 1.5-2.5 h to obtain space-grade silicone rubber.

5. A space solar cell array according to claim 4, characterized in that: The mass ratio of the low-phenyl silicone rubber base, methyltriethoxysilane, n-hexane, hydroxyl polyhedral oligomeric silsesquioxane, modified boron nitride filler, and dibutyltin dilaurate is 25:1.5:10:5:11:

1.

6. A space solar cell array according to claim 4, characterized in that: The preparation steps of the hydroxyl polyhedral oligomeric silsesquioxane are as follows: Ammoniated trialkoxysilane, triethylamine, chloropropanol, and toluene were mixed and reacted at 45–55 °C for 4–6 h. The mixture was then separated, and the liquid component was distilled to obtain a hydroxyl polyhedral oligomeric silsesquioxane precursor. The hydroxyl polyhedral oligomeric silsesquioxane precursor, trifluoromethanesulfonic acid, and distilled water were mixed and reacted with stirring at 20–25 °C for 1–3 h. The mixture was then distilled under reduced pressure at 70 °C for 1–3 h. After cooling to 20–25 °C, the mixture was washed with acetone, filtered, and dried under vacuum to obtain the hydroxyl polyhedral oligomeric silsesquioxane.

7. A space solar cell array according to claim 6, characterized in that: The mass ratio of aminopropyltrialkoxysilane, triethylamine, chloropropanol and toluene is 18:10:9.4:80; the mass ratio of hydroxyl polyhedral oligomeric silsesquioxane precursor, trifluoromethanesulfonic acid and distilled water is 4.38:4.5:

60.

8. A space solar cell array according to claim 4, characterized in that: The preparation steps of the modified boron nitride filler are as follows: S1: Aluminum chloride hexahydrate, anhydrous ethanol, and deionized water were mixed to prepare an aluminum chloride solution with a concentration of 0.5 mol / L. Boron nitride nanosheets were added to obtain a mixed solution. A 1.8 mol / L ammonia solution was added dropwise to the mixed solution, stirred for 10-15 min, centrifuged at 2950-3050 r / min, washed and centrifuged multiple times with anhydrous ethanol, and dried at 55-65℃ for 9-11 h to obtain the precursor aluminum hydroxide-boron nitride nanosheets. S2: The precursor aluminum hydroxide-boron nitride nanosheets were calcined at a temperature gradient of 5℃ / min to obtain the modified boron nitride filler.

9. A space solar cell array according to claim 8, characterized in that: The mass ratio of aluminum chloride hexahydrate, anhydrous ethanol, deionized water, and boron nitride nanosheets in S1 is 6.05:237.5:12.5:5.5; the gradient heating conditions in S2 are to hold at 500℃, 700℃, 900℃, and 1200℃ for 1~1.5h each.

10. A method for fabricating a space solar cell array according to any one of claims 1-9, characterized in that: Includes the following steps: Step 1: From bottom to top, lay the flexible buffer film material on the back side, the solar cells connected in series with the metal interconnect strip on the substrate, connect the solar cells connected in series with the metal interconnect strip, the bypass diode, the isolation diode and the wire to complete the electronic circuit laying and connection, and obtain the solar cell array module. Step 2: Place the front transparent buffer film material and the front transparent encapsulation material on the solar cell array module in sequence, and then fix them with a clamping mechanism to obtain the space solar cell array.

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