Condensation module for space

Abstract

The invention discloses a light condensation module for space. The light condensation module comprises a primary mirror, a secondary mirror, a secondary mirror support, a light funnel, a battery piece and a heat expansion piece. The primary mirror comprises a primary mirror base body which forms a sunny side opening of the condensation module, and an optical working surface of the primary mirror faces the secondary mirror; the secondary mirror is fixed to a reflection light path convergence area of the primary mirror through a secondary mirror support, and secondary reflection is carried out on reflection light of the primary mirror to an inlet of the light funnel. The light funnel is of a conical cavity structure and guides light to the light receiving face of the battery piece. The heat expansion piece is tightly attached between the back face of the battery piece and the primary mirror base body. The primary mirror base body is used as a heat dissipation element, a heat conduction path of'battery piece-heat expansion piece-primary mirror base body 'is constructed, integration of optical convergence and heat management is achieved, heat is radiated to a space environment through the surface of the primary mirror while the light condensation efficiency is guaranteed, the working temperature of the battery piece is effectively controlled, an independent heat dissipation component is not needed, and the cost is reduced. The device has the advantages of compact structure and light weight.

Description

Technical Field

[0001] This invention relates to the field of space solar power generation technology, specifically to a space-based concentrating module. Background Technology

[0002] Space-based solar power systems are the primary energy source for spacecraft, space stations, and various space platforms. Among them, concentrated photovoltaic (CPV) technology, which uses optical systems to focus solar radiation and effectively increase the power output density of solar cells, has become an important technological approach to meet the high power requirements of space missions.

[0003] Currently, the main types of solar concentrating technologies used in space applications include refractive and reflective types. Refractive concentrating systems typically use optical elements such as Fresnel lenses, and their structure is relatively simple. However, in practical applications, they suffer from insufficient uniformity of the concentrated light spot and require high precision in solar tracking. Reflective concentrating systems utilize reflecting mirrors to converge light, resulting in relatively high optical efficiency. However, common reflective structures often require complex optical surfaces and precise alignment mechanisms, increasing the system's manufacturing difficulty and assembly complexity.

[0004] In the vacuum environment of space, heat dissipation can only be achieved through radiation. When a concentrator module is operating, the solar cells bear the large amount of heat generated by high-concentration light. If an effective heat dissipation path cannot be established, the cell temperature will rise, affecting its photoelectric conversion efficiency and service life. In existing technologies, independent heat dissipation components (such as heat pipes and heat sinks) are typically used for thermal management. This split design increases the system's mass and volume, and the cumulative thermal resistance due to the long heat conduction path limits the overall heat dissipation efficiency.

[0005] Furthermore, there is room for optimization in the optical path design of traditional focusing modules. Some solutions employ complex optical systems, resulting in bulky structures, while simpler optical structures struggle to achieve efficient utilization of light energy. These factors all limit further improvements in the performance of space focusing modules.

[0006] Therefore, there is still room for improvement in the optical design, thermal management and system integration of existing space-use focusing modules, and an integrated solution that can balance high focusing efficiency, efficient heat dissipation and compact structure is needed. Summary of the Invention

[0007] The present invention aims to provide a space-based focusing module to solve the problems of existing space focusing technologies where the optical focusing system and the thermal management system are separated, resulting in complex system structure, long heat dissipation path, high thermal resistance, and increased overall weight and volume.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A space-based light-concentrating module includes a primary mirror, a secondary mirror, a secondary mirror support, a light funnel, a solar cell, and a heat-diffusing plate. The primary mirror includes a primary mirror base, which forms the sun-facing opening of the light-concentrating module. Its optical working surface is positioned facing the secondary mirror to receive and reflect incident sunlight. The secondary mirror is fixed above the primary mirror by the secondary mirror bracket and is located in the convergence area of ​​the reflected light path of the primary mirror. Its optical working surface faces the entrance of the light funnel and is used to perform secondary reflection of the light reflected by the primary mirror. The light funnel has a conical cavity structure, with its inlet receiving the reflected light path of the secondary mirror and its outlet corresponding to the light-receiving surface of the solar cell, and is used to guide the light reflected by the secondary mirror to the solar cell. The battery cell is positioned below the light path outlet of the light funnel and is used to convert light energy into electrical energy; The heat-diffusing plate is tightly attached between the back of the battery cell and the primary mirror substrate, and is used to conduct the heat generated by the battery cell during operation to the primary mirror substrate; wherein... The primary mirror substrate also serves as a heat dissipation element for the light-concentrating module, radiating the heat conducted from the heat spreader to the space environment via its surface.

[0009] Compared with the prior art, the focusing module provided by the present invention has the following advantages: 1) Achieving an integrated design for optical focusing and thermal management. By using the primary mirror substrate as a heat dissipation element and placing a heat spreader tightly attached between the back of the solar cell and the primary mirror substrate, a short-path heat conduction channel is constructed from the solar cell to the heat spreader to the primary mirror substrate. This design utilizes the primary mirror's own structure for heat dissipation, eliminating the need for an additional independent heat dissipation component, simplifying the system structure and achieving weight reduction.

[0010] 2) Establish a stable secondary reflection light path. The secondary mirror is fixed to the converging area of ​​the primary mirror's reflected light path via a secondary mirror bracket and aligned with the entrance of the light funnel, forming a complete light path transmission chain of "primary mirror - secondary mirror - light funnel - solar cell". The conical cavity structure of the light funnel can guide and converge light to the solar cell, which can improve light energy utilization efficiency and light concentration uniformity.

[0011] 3) Improve system heat dissipation efficiency and operational stability. The heat generated by the solar cells is directly conducted to the primary mirror substrate, which has a large surface area, through the heat spreader, and then radiated from the surface of the primary mirror substrate to the space environment. This integrated thermal management path shortens the heat conduction distance, reduces interfacial thermal resistance, and can control the operating temperature of the solar cells, maintaining their photoelectric conversion efficiency and long-term reliability.

[0012] 4) Enhanced environmental adaptability. The modular integrated structure reduces reliance on additional heat dissipation devices, thereby reducing system complexity and potential failure points. The primary mirror, as the main heat dissipation surface, is adapted to the space radiation heat dissipation environment. The robust secondary mirror support structure and the optical funnel's constraint on the optical path enable the overall structure to withstand the mechanical loads during the launch phase and environmental disturbances during on-orbit operation.

[0013] In summary, this invention, through its integrated light-thermal design, solves the heat dissipation problem while achieving efficient light concentration, providing a compact and stable light-concentrating module solution for space solar energy applications. Attached Figure Description

[0014] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of a space-use focusing module proposed in this invention; Figure 2 This is a schematic diagram of the heat dissipation path of the solar cell in the space-use concentrating module proposed in this invention; Figure 3 This is a schematic diagram of the outward thermal radiation path of the primary mirror substrate of the space-use focusing module proposed in this invention.

[0015] In the figure: 1. Primary mirror; 101. Primary mirror substrate; 102. Reflective layer; 103. Transparent infrared radiation layer; 104. Thermally conductive radiation layer; 3. Secondary mirror; 4. Secondary mirror support; 5. Battery cell; 6. Optical funnel; 7. Heat diffuser; 41. Mounting plane; 42. Hollowed-out part; 71. Positioning groove. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. The described embodiments are only a part of the implementation of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] It should be noted that, in the description of this invention, "an embodiment" or "an embodiment of the invention" refers to a specific feature, structure, or characteristic that can be included in at least one implementation of the invention. The phrase "in one embodiment" appearing in different places in the specification does not necessarily refer to the same embodiment, nor are they mutually exclusive individual or selective embodiments. This invention can also be implemented in ways other than those described herein, and any equivalent modifications made by those skilled in the art without departing from the concept of the invention fall within the scope of protection of this invention.

[0018] In space-based concentrated photovoltaic (CCP) systems, the concentrating module is the key component for achieving high-concentration power generation. Traditional space-based CCP modules typically treat optical focusing and thermal management as two separate systems: the optical system uses components such as primary and secondary mirrors to focus the light, while the thermal management system requires additional independent heat dissipation components, such as heat pipes or heat sinks, to dissipate the large amount of heat generated by the solar cells. This discrete design leads to a complex system structure, increased mass, and limited heat dissipation efficiency due to long heat conduction paths and high interfacial thermal resistance. Furthermore, the solar radiation heat absorbed by the primary mirror itself lacks an effective heat dissipation path, which may cause thermal deformation due to temperature rise, affecting the accuracy of the optical surface profile.

[0019] To address the aforementioned issues, this invention proposes a space-based focusing module design integrating optical and thermal functions. The core of this design lies in enabling the primary mirror substrate to not only perform optical reflection but also act as a heat dissipation element. A direct heat conduction path is established from the solar cell via a heat spreader to the primary mirror substrate, and heat is radiated to the space environment through the primary mirror surface. Specific implementation methods include: setting a heat spreader to tightly connect the solar cell and the primary mirror substrate, forming an efficient heat conduction channel; optimizing the structure and surface characteristics of the primary mirror substrate to enhance its radiative heat dissipation capacity; and fixing the position of the secondary mirror using a secondary mirror bracket to ensure precise alignment of the secondary reflection light path with the light funnel inlet. This integrated design achieves a synergistic improvement in optical performance and thermal management efficiency, effectively meeting the heat dissipation requirements of high-magnification focusing applications in space without introducing an independent heat dissipation system.

[0020] See Figure 1 and Figure 3 The present invention proposes a space-based light-concentrating module, comprising a primary mirror 1, a secondary mirror 3, a secondary mirror support 4, a light funnel 6, a battery cell 5, and a heat-diffusing plate 7; The primary mirror 1 includes a primary mirror base 101, which forms the sun-facing opening of the light-concentrating module. Its optical working surface is set towards the secondary mirror 3 to receive and reflect incident sunlight. The secondary mirror 3 is fixed above the primary mirror 1 by the secondary mirror bracket 4 and is located in the convergence area of ​​the reflected light path of the primary mirror 1. Its optical working surface faces the entrance of the light funnel 6 and is used to perform secondary reflection of the light reflected by the primary mirror 1. The light funnel 6 has a conical cavity structure. Its inlet receives the reflected light path of the secondary mirror 3, and its outlet corresponds to the light-receiving surface of the solar cell 5. It is used to guide the light reflected by the secondary mirror 3 to the solar cell 5. The battery cell 5 is positioned below the light path outlet of the light funnel 6 and is used to convert light energy into electrical energy; The heat-dissipating plate 7 is tightly attached between the back of the battery cell 5 and the primary mirror substrate 101, and is used to conduct the heat generated by the battery cell 5 during operation to the primary mirror substrate 101; wherein, The primary mirror substrate 101 also serves as a heat dissipation element for the light-concentrating module, radiating the heat conducted from the heat spreader 7 to the space environment through its surface.

[0021] The focusing module proposed in this invention integrates optical focusing and thermal management functions by simultaneously using the primary mirror substrate 101 as a heat dissipation element. Specific improvements are as follows: In terms of system structure, the primary mirror substrate 101 combines optical reflection and heat dissipation functions. By setting a heat spreader to connect the battery cell and the primary mirror substrate, a heat conduction path of "battery cell - heat spreader - primary mirror substrate" is formed, which quickly dissipates the high-density heat generated by the battery cell 5 and radiates heat to the space environment through the surface of the primary mirror substrate 101. This functional reuse avoids the need for additional independent heat dissipation components, thereby simplifying the system structure.

[0022] In terms of optical path design, a complete optical path transmission chain was constructed, consisting of a primary mirror, a secondary mirror, an optical funnel, and a solar cell. The primary mirror 1 reflects sunlight to the secondary mirror 3, which performs secondary reflection and guides the light to the inlet of the optical funnel 6. The optical funnel 6 then uses a conical cavity structure to converge the light onto the light-receiving surface of the solar cell 5, achieving efficient utilization of light energy.

[0023] Compared to traditional concentrating modules, existing technologies typically employ a separate design for the optical and thermal management systems, such as using thermal interface materials or heat pipes to conduct heat from the solar cells to a separate heat sink. This approach has limitations in terms of system structure and weight, and the long heat dissipation path and high thermal resistance limit the overall heat dissipation efficiency.

[0024] In contrast, this invention integrates heat dissipation into optical components through an integrated optical-thermal architecture, shortening the heat conduction distance from the battery cell to the heat dissipation surface, which helps to improve heat dissipation efficiency and simplifies the system structure while maintaining optical performance.

[0025] In summary, this invention achieves integrated optimization in terms of heat dissipation path, optical transmission efficiency, and structural simplification through an integrated light-thermal design, providing a solution for space-based concentrated photovoltaic systems that balances heat dissipation performance and lightweight requirements.

[0026] In one embodiment, see still Figure 1 The primary mirror substrate 101 adopts a near-parabolic spherical structure with a quadrilateral outline; its concave surface serves as the optical working surface, and a reflective layer 102 and a transparent infrared radiation layer 103 covering the reflective layer 102 are sequentially provided. The transparent infrared radiation layer 103 is used to radiate the heat absorbed by the primary mirror substrate 101 into the space environment in the form of infrared radiation.

[0027] The near-parabolic spherical structure of the primary mirror substrate 101 provides a relatively large effective light-receiving area and good structural rigidity for the same aperture, effectively reflecting parallel-incident sunlight to the secondary mirror 3 position, providing an optical basis for high-magnification light concentration. Simultaneously, the quadrilateral outline provides a structural boundary for modular integration, allowing multiple concentrating modules to be arranged in a matrix on the surface of the solar array. This quadrilateral outline facilitates stable connections with adjacent modules and support frames, enhancing overall structural rigidity. Furthermore, this configuration is adaptable to manufacturing processes, facilitating processing, assembly, and testing.

[0028] A composite structure of a reflective layer 102 and a transparent infrared radiation layer 103 is provided on the concave optical working surface of the primary mirror substrate 101, enabling the optical working surface to possess both efficient reflection and radiative heat dissipation functions. The high transmittance characteristics of the transparent infrared radiation layer 103 ensure the optical performance of the underlying reflective layer 102, while its high infrared emissivity enhances the radiative heat dissipation capability of the surface. At the same time, the upper transparent infrared radiation layer 103 provides space environment protection for the underlying reflective layer 102, which can slow down its performance degradation in the space environment.

[0029] Preferably, the reflective layer 102 is a silver-plated layer. The silver-plated layer has high reflectivity (typically >95%) in the visible to near-infrared band, capable of reflecting most of the sunlight energy to the secondary mirror while reducing the absorption of light energy by the primary mirror substrate 101, thus helping to reduce the heat generation of the primary mirror substrate itself. Furthermore, as the bottom reflective functional layer, the excellent optical performance of the silver-plated layer provides the foundation for the functionality of the upper infrared radiation layer. The infrared radiation layer mainly undertakes transmission and heat dissipation functions, without needing to meet high reflectivity requirements. This allows each functional layer to perform its specific function, achieving coordinated operation of reflection, transmission, and heat dissipation.

[0030] In summary, the embodiments of the present invention achieve comprehensive improvement of the focusing module in terms of maintaining optical performance, improving heat dissipation efficiency, and surface stability by designing the primary mirror substrate 101 with a near-parabolic spherical structure with a quadrilateral outline and integrating a dual-functional layer for reflection and infrared radiation on its concave surface.

[0031] In one embodiment, the transparent infrared radiation layer 102 includes a transparent polymer matrix and modified SiO2 nanoparticles, modified ZrO2 nanoparticles and boron nitride nanosheets dispersed in the matrix. Based on 100 parts by weight of the transparent polymer matrix, the amount of modified SiO2 nanoparticles added is 0.1-5 parts, the amount of modified ZrO2 nanoparticles added is 0.1-3 parts, and the amount of boron nitride nanosheets added is 0.1-2 parts.

[0032] The transparent infrared radiation layer used in this invention abandons single or two-component filler systems and, for the first time, synergistically combines three specific inorganic nanofillers—modified SiO2 nanoparticles, modified ZrO2 nanoparticles, and boron nitride nanosheets—in a transparent polymer matrix. These three fillers differ fundamentally in chemical composition, morphology, and physical properties, and their combination constitutes a novel material system.

[0033] Moreover, this transparent infrared radiation layer is not simply a mixture of the three fillers. Instead, a specific range of addition amounts (based on 100 parts of the polymer matrix) was determined through extensive experiments to achieve the best synergistic effect among the three: modified SiO2 nanoparticles: 0.1-5 parts, modified ZrO2 nanoparticles: 0.1-3 parts, and boron nitride nanosheets: 0.1-2 parts. This formulation design aims to balance the function of each filler and avoid the degradation of optical or mechanical properties due to an excess of any one filler.

[0034] The modified ZrO2 nanoparticles and boron nitride nanosheets in the transparent infrared radiation layer exert a synergistic effect through the following mechanism: In terms of infrared performance, phonon polaritons excited on the surface of boron nitride nanosheets couple with the optical phonon modes of ZrO2 nanoparticles, forming a phonon-polariton hybrid mode. This coupling produces localized field enhancement and resonant absorption in the 8–20 μm band, thereby broadening and planarizing the emission spectrum of the coating. Simultaneously, the high in-plane thermal conductivity of boron nitride nanosheets facilitates the construction of a two-dimensional thermally conductive network within the coating, synergistically reducing interfacial thermal resistance, promoting phonon transport, and improving overall heat dissipation efficiency with the ZrO2 nanoparticles.

[0035] In terms of mechanical properties, modified ZrO2 nanoparticles act as primary barriers, consuming some energy by inducing crack deflection and pinning; boron nitride nanosheets, acting as toughening units, further promote crack deflection, bypassing, and bifurcation, and constrain crack opening through bridging. The strong interfacial bonding between the two helps to uniformly transfer and disperse the load. Boron nitride nanosheets dissipate energy through interlayer slip, while ZrO2 nanoparticles assist in stress transfer to the boron nitride layer, jointly inhibiting microcrack initiation. In the later stages of crack propagation, the pull-out process of boron nitride nanosheets needs to overcome interfacial friction and van der Waals forces to further absorb fracture energy, thereby transforming the failure mode into pseudo-plastic fracture and improving the fracture toughness of the coating.

[0036] It is evident that the composite introduction of modified ZrO2 nanoparticles and boron nitride nanosheets, through the synergistic effect of phonon polariton coupling and lattice vibration, extends the infrared emission window of the coating from the traditional 8-14 μm to a broad 8-20 μm region, thereby improving its radiative heat dissipation efficiency in a vacuum environment. In terms of mechanical properties, the two form a synergistic toughening mechanism: the modified ZrO2 nanoparticles act as a primary barrier to induce crack deflection, while the boron nitride nanosheets further dissipate fracture energy through crack bridging, stress dispersion, and lamellar pull-out mechanisms, effectively inhibiting crack initiation and propagation, and jointly enhancing the fracture toughness of the coating.

[0037] In summary, by providing the transparent infrared radiation layer 103 of this embodiment of the invention on the reflective layer 102 of the concave surface of the primary mirror substrate 101, the following technical effects can be expected to be achieved: First, it achieves high infrared emissivity across a broad spectrum. The three nanofillers possess different intrinsic infrared absorption characteristics. Modified SiO2, modified ZrO2, and boron nitride nanosheets may contribute to phonon vibrations and phonon polaritons at different characteristic frequencies in the mid-to-far infrared band of 8-20 μm, respectively. Their synergistic effect can cover a wider infrared band, filling the emission blind spots of single-material systems, thereby jointly achieving and maintaining high infrared emissivity within this broad spectrum.

[0038] Secondly, it maintains high visible light transmittance. By controlling the total amount of the three types of nanofillers at a low level (maximum 10 parts) and preferably using nanoscale, it helps to reduce the scattering of visible light, allowing the coating to maintain high transmittance at a wavelength of 550 nm.

[0039] Third, it enhances the mechanical properties and durability of the coating. Three different morphologies and sizes of nanofillers (such as nearly spherical SiO2 / ZrO2 and plate-like boron nitride) dispersed in the polymer matrix can construct a multi-scale reinforcing and toughening network. Nanoparticles can act as stress concentration points, inducing microcrack deflection; boron nitride nanosheets, with their two-dimensional structure and high strength, hinder crack propagation through bridging, synergistically improving the fracture toughness and crack resistance of the coating.

[0040] In one embodiment, the modified ZrO2 nanoparticles are doped with MgO, and the doping amount of MgO is 0.01-2 mol.

[0041] In this embodiment, modified ZrO2 nanoparticles are doped with MgO. This doping treatment affects the material properties through the following mechanism: 1) Regarding infrared performance, MgO doping introduces lattice distortion and oxygen vacancy defects. Lattice distortion may alter the phonon vibration modes of ZrO2, while oxygen vacancy defects generate additional light absorption in the 2.5–8 μm wavelength range. These effects, combined with the infrared characteristics of components such as SiO2 and boron nitride, positively impact the broad-spectrum emission performance of the coating in the 8–20 μm wavelength range.

[0042] 2) In terms of material processability, appropriate MgO doping helps to suppress the grain growth and agglomeration tendency of ZrO2 nanoparticles. Improved dispersibility is conducive to the formation of a more uniform composite structure in the polymer matrix, reducing visible light scattering caused by agglomeration, and at the same time supporting the maintenance of the visible light transmittance of the coating.

[0043] 3) In terms of mechanical properties, the improved dispersibility of MgO-doped ZrO2 nanoparticles allows for a more uniform distribution within the matrix, forming a more effective synergistic toughening structure with boron nitride nanosheets. This structure positively impacts the fracture toughness of the coating through mechanisms such as crack deflection and bridging.

[0044] In summary, the embodiments of the present invention improve the functionality of the ZrO2 component from the intrinsic material property level by doping ZrO2 nanoparticles with a specific amount of MgO. Through microstructure regulation, the broadband infrared emission performance of the coating is synergistically enhanced, and its optical performance and mechanical reliability are indirectly consolidated by optimizing the dispersibility.

[0045] In one embodiment, the modified SiO2 nanoparticles have an average particle size of 5-30 nm; the modified ZrO2 nanoparticles have an average particle size of 10-50 nm.

[0046] The physical dimensions of the modified SiO2 nanoparticles and modified ZrO2 nanoparticles in this embodiment are limited as described above, based on the following technical considerations: In terms of optical properties, controlling the particle size of modified SiO2 nanoparticles within the range of 5–30 nm helps reduce their scattering of visible light, thus supporting the maintenance of the coating's high transmittance at 550 nm. Simultaneously, setting the particle size of modified ZrO2 nanoparticles to 10–50 nm aligns with their phonon vibration characteristics in the mid- and far-infrared bands, which helps enhance phonon coupling between them and boron nitride nanosheets, thereby positively impacting the broadening of the infrared emission band.

[0047] In terms of structural properties, the aforementioned nanoscale particle size helps to suppress filler agglomeration and sedimentation, promoting its uniform dispersion in the polymer matrix and providing a foundation for the uniformity of the coating's optical and mechanical properties. Furthermore, nanoparticles of different sizes, together with plate-like boron nitride, construct a multi-scale composite structure. When the coating is subjected to stress, this structure can dissipate energy through crack deflection and bifurcation, thereby enhancing the coating's fracture toughness.

[0048] In summary, by limiting the average particle size range of modified SiO2 and modified ZrO2 nanoparticles, the embodiments of the present invention help to control the visible light transmittance, infrared emission characteristics and mechanical behavior of the coating.

[0049] In one embodiment, the boron nitride nanosheets have a lateral dimension of 1-50 nm and a thickness of 1-50 nm.

[0050] The size range of boron nitride nanosheets, especially their thickness which is much smaller than the wavelength of visible light, helps to reduce the scattering and blocking of visible light by the boron nitride nanosheets, thereby playing a positive role in maintaining the overall high visible light transmittance of the coating.

[0051] At this nanoscale, boron nitride nanosheets can effectively excite phonon polaritons and couple with the lattice vibrations of modified ZrO2 nanoparticles. This may broaden the infrared emission band of the coating and contribute to achieving broadband infrared emission in the 8-20 μm band.

[0052] Boron nitride nanosheets, confined to this size range, facilitate uniform dispersion within the polymer matrix and form a multi-scale composite structure with modified SiO2 and modified ZrO2 nanoparticles. This structure provides conditions for energy dissipation through mechanisms such as crack deflection and bridging, thereby influencing the improvement of the coating's fracture toughness.

[0053] In summary, the boron nitride nanosheets in this embodiment of the invention are limited by the above-mentioned size based on considerations of the influence of the coating on optical transmittance, infrared emission characteristics and mechanical properties.

[0054] In one embodiment, both the modified SiO2 nanoparticles and the modified ZrO2 nanoparticles are surface-modified with a silane coupling agent. Preferably, the silane coupling agent is selected from at least one of vinylsilane, epoxysilane, aminosilane, or methacryloxysilane.

[0055] This modification treatment reduces the surface energy of nanoparticles, weakens their agglomeration tendency, and thus promotes their uniform dispersion in the polymer matrix. Based on this, one end of the silane coupling agent molecule can bind to the surface of inorganic nanoparticles, while the other end is compatible with or reacts with the organic polymer matrix, thereby establishing an interfacial connection between the filler and the matrix and enhancing the bonding force between them. The resulting technical effects include: uniform dispersion of the filler helps reduce light scattering centers caused by agglomerate formation, thus supporting the maintenance of high transmittance of the coating in the visible light region; simultaneously, the improved interfacial bonding facilitates more effective stress transfer from the matrix to the nanofiller, allowing the nanoparticles to participate more fully in the load-bearing and toughening process, thereby positively impacting the stability of the coating's mechanical properties.

[0056] In summary, the surface modification of SiO2 and ZrO2 nanoparticles in this embodiment of the invention is a key step in achieving uniform dispersion and enhanced interfacial bonding, which helps to synergistically optimize the overall performance of the coating.

[0057] In one embodiment, the present invention further proposes that the coating thickness of the infrared radiation layer is 10-30 μm.

[0058] Maintaining the coating thickness within the range of 10-30 μm helps balance visible light transmission and infrared radiation emission efficiency. When the coating thickness is less than 10 μm, the effective material content of the infrared radiation functional layer may be insufficient, making it difficult to form a continuous and complete radiation surface, thus affecting its broadband emission efficiency in the 8-20 μm wavelength band. Conversely, when the coating thickness exceeds 30 μm, the cumulative effect of intrinsic material absorption and interface reflection may adversely affect visible light transmittance. This 10-30 μm thickness range allows the coating to maintain high visible light transmittance while possessing sufficient infrared radiation material carrying capacity.

[0059] A coating thickness of 10-30 μm is beneficial for forming a structurally complete film. Within this range, the coating can fully cover the substrate surface, avoiding discontinuities caused by an excessively thin film and preventing stress buildup during curing due to an excessively thick film, thus reducing the risk of cracking. Furthermore, this thickness range is well-suited for wet coating processes such as spraying, facilitating precise coating through process parameter control.

[0060] This thickness design also helps improve the mechanical properties of the coating. A coating that is too thin may compromise its scratch resistance due to insufficient mechanical strength; a coating that is too thick may weaken its bond strength with the substrate due to increased internal stress. Maintaining a thickness of 10-30 μm preserves the coating's structural strength while ensuring good interfacial bonding, thus improving the reliability of the primary mirror in aerospace environments.

[0061] In summary, by limiting the thickness of the infrared radiation layer to 10-30 μm, the embodiments of the present invention achieve a balance between optical performance, structural integrity, and environmental adaptability, providing structural parameter support for the functional layer to achieve stable broadband radiation heat dissipation function.

[0062] In one embodiment, see still Figure 1 The convex surface of the primary mirror substrate is provided with a thermally conductive radiation layer 104, which is a graphene film, used to diffuse the heat absorbed by the primary mirror substrate laterally and radiate it to the space environment.

[0063] The thermally conductive radiation layer 104, disposed on the convex surface of the primary mirror substrate 101, has a high in-plane thermal conductivity, enabling it to rapidly diffuse the heat absorbed by the primary mirror substrate, especially the localized high-density heat flow conducted from the solar cells, along the planar direction of the substrate. This lateral heat diffusion effect helps prevent heat accumulation in localized areas, thus improving the overall temperature distribution uniformity of the primary mirror substrate and creating conditions for effective radiative heat dissipation. The thermally conductive radiation layer 104 works in conjunction with the transparent infrared radiation layer 103 on the concave surface of the primary mirror substrate 101 to jointly constitute a double-sided heat dissipation system for the primary mirror substrate.

[0064] The thermally conductive radiation layer 104 is preferably a graphene film layer. This graphene film is a two-dimensional nanomaterial composed of carbon atoms and possesses the following excellent properties: ① The graphene film has high in-plane thermal conductivity (>1500 W / m·K), allowing it to work in conjunction with the heat spreader to rapidly diffuse the high-density heat generated by the solar cell and laterally conducted through the heat spreader to the entire primary mirror substrate, thus achieving uniform temperature, helping to avoid localized overheating, ensuring the safety of the solar cell, and providing a large surface area for heat radiation into space. ② The graphene film itself is also an excellent infrared radiation material with a certain infrared emissivity (>0.9), allowing it to directly radiate some heat. ③ The graphene film has a thickness on the micrometer scale and its mass is almost negligible, having a minimal impact on the system's weight gain. ④ The flexible nature of the graphene film allows it to adapt to thermal deformation under temperature changes, avoiding interfacial delamination caused by thermal stress.

[0065] Therefore, it can be seen that the concave surface of the primary mirror substrate 101 is a functional stack composed of a reflective layer 102 and a transparent infrared radiating layer 103, enabling the concave surface of the primary mirror substrate 101 to simultaneously possess high reflectivity and infrared emissivity, which helps to achieve the integration of the optical surface and the radiative heat dissipation surface. The thermally conductive radiating layer 104 on the convex surface of the primary mirror substrate 101 works in conjunction with the heat expansion sheet 7 to jointly construct a low thermal resistance heat conduction path from the battery cell 5 to the primary mirror substrate 101. The specific heat transfer process includes: ① First-stage lateral heat diffusion: The high-density heat flow generated by the battery cell 5 is first absorbed by the heat diffusion plate 7 attached to it and diffused laterally to reduce the heat flow density and avoid the formation of local hot spots under the battery cell 5.

[0066] ② Secondary lateral temperature uniformity: After the heat is conducted to the primary mirror substrate 101 through the heat spreader 7, the heat-conducting radiation layer 104 attached to the convex surface of the primary mirror substrate uses its ultra-high in-plane thermal conductivity to rapidly diffuse the heat laterally to the entire primary mirror substrate to achieve temperature uniformity.

[0067] The heat is ultimately radiated into the space environment through the convex and concave dual surfaces of the primary mirror substrate 101, forming an efficient heat dissipation path for the solar cell from "solar cell → heat spreader → primary mirror substrate (convex surface + concave surface) → space environment". See [link to solar cell heat dissipation path] for details. Figure 2 As shown.

[0068] This dual-layer design of the primary lens allows it to perform its light-gathering function while also possessing good heat dissipation capabilities. (See also...) Figure 3 When the focusing module is working, sunlight penetrates the transparent infrared radiation layer 103, is reflected by the reflective layer 102 towards the secondary mirror 3, and is then reflected a second time by the secondary mirror 3 to the solar cell 5. The high-density heat flow generated by the photoelectric conversion of the solar cell 5 is first absorbed by the heat spreader 7 immediately below it and undergoes primary lateral diffusion. Then, the heat is conducted through the heat spreader 7 to the primary mirror substrate 101. The solar radiation heat absorbed by the primary mirror substrate 101 itself and the heat conducted from the solar cell 5 are dissipated through two paths: one is direct outward thermal radiation through the concave transparent infrared radiation layer 103 (thermal path B1); the other is outward thermal radiation through the convex thermal conductive radiation layer 104 after secondary lateral temperature equalization (thermal path B2). This dual-sided heat dissipation collaborative design of "concave reflection + heat dissipation, convex thermal conduction + heat dissipation" improves heat dissipation efficiency while ensuring the optical performance of the primary mirror, helps to suppress the thermal deformation of the primary mirror, and ensures the stability of the focusing optical path.

[0069] In summary, the thermally conductive and radiative layer on the convex surface of the primary mirror substrate in this embodiment of the invention enhances lateral thermal conductivity and radiative heat dissipation capabilities. Furthermore, by employing graphene film as a high thermal conductivity and radiative layer, efficient lateral thermal conductivity and radiative heat dissipation are achieved while also meeting the system's lightweight requirements. This integrated design avoids the use of additional heat dissipation components, contributing to a compact and lightweight structure and providing a technical foundation for the stable operation of the focusing module.

[0070] In one embodiment, see continue to see Figure 1 and Figure 3 The concave center of the primary mirror substrate 101 is provided with a positioning groove 71; the battery cell 7 is placed directly above the positioning groove 71, and the heat expansion plate 7 is placed inside the positioning groove 71.

[0071] A positioning groove 71 is provided at the center of the concave surface of the primary mirror substrate 101, providing a definite installation position for the heat expansion plate 7. This ensures that the heat expansion plate 7 and the primary mirror substrate 101, as well as the heat expansion plate 7 and the upper battery cell 5, maintain a precise relative position, promoting close physical contact among the three, thereby establishing a low thermal resistance heat conduction path from the battery cell 5 to the primary mirror substrate 101.

[0072] The structural design of the positioning groove 71 helps to increase the contact area between the heat spreader 7 and the primary mirror substrate 101, and can further reduce the contact thermal resistance by filling it with thermally conductive interface material. This optimizes the efficiency of high-density heat conduction from the battery cell 5 to the primary mirror substrate 101 through the heat spreader 7, creating favorable conditions for subsequent radiative heat dissipation through both sides of the primary mirror substrate 101.

[0073] Furthermore, the positioning groove 71 makes the installation process of the heat spreader 7 simpler and more reliable, reducing the difficulty of alignment during assembly. At the same time, the structure of the positioning groove 71 can cover or limit the heat spreader 7, improving its positional stability under space environment loads such as mechanical vibration, impact and thermal cycling, preventing the decrease in thermal conductivity or structural failure caused by relative displacement of the interface, and ensuring the long-term operational reliability of the primary mirror 1.

[0074] In summary, by setting a positioning groove at the center of the concave surface of the primary mirror substrate, the embodiments of the present invention provide an important structural guarantee for the effective thermal management of the focusing module in terms of thermal interface optimization, heat dissipation efficiency improvement and assembly reliability.

[0075] In one embodiment, the secondary mirror has a near-hyperboloid surface structure, with a reflective medium film on its optical working surface and a heat dissipation coating on its non-optical working surface.

[0076] The secondary mirror adopts a near-hyperboloid design, forming a classic Cassegrain structure with the near-parabolic spherical primary mirror. The two form a synergistic optical system, which can effectively correct the optical path, improve the beam converging effect, and help optimize the beam quality to form a light spot that meets the requirements on the surface of the solar cell.

[0077] The reflective medium film on the optical working surface of the secondary mirror is a multilayer interference thin film prepared through processes such as vacuum deposition. This reflective medium film is optimized for the solar spectrum and has high reflectivity, which can reduce the loss of light energy during the reflection process of the secondary mirror.

[0078] The heat dissipation coating on the non-optical working surfaces of the secondary mirror, such as the back and sidewalls, uses materials with high infrared emissivity and low solar absorptivity, such as aerospace-grade inorganic white paint. Although the reflective dielectric film on its optical working surfaces significantly reduces light absorption, the secondary mirror still heats up due to external heat flow and residual energy absorption. This heat dissipation coating enhances the infrared emissivity of the non-optical working surfaces, promoting the dissipation of accumulated heat from the secondary mirror into the space environment.

[0079] In summary, the embodiments of the present invention, by adopting a near-hyperbolic surface shape and combining it with a double-sided functional coating design, achieve beam conduction while also taking into account the requirements for operating temperature control, which helps to maintain the optical performance stability of the focusing module.

[0080] In one embodiment, see still Figure 1 The primary mirror base 101 has mechanical mounting surfaces 41 at its four corners. The secondary mirror support 4 adopts a long, rod-shaped structure and has a hollowed-out portion 42. The two ends of the support are fixedly connected to two mounting surfaces on opposite diagonals of the primary mirror base 101.

[0081] The mounting planes located at the four vertices of the quadrilateral outline of the primary mirror base 101 provide defined mounting interfaces for the secondary mirror bracket 4. The support frame formed by the quadrilateral frame and the mounting planes enhances the rigidity of the edge region of the primary mirror base 101, enabling it to withstand the assembly stress and on-orbit temperature load transmitted by the secondary mirror bracket 4, thereby suppressing structural deformation and maintaining the stability of the primary mirror surface.

[0082] The two ends of the secondary mirror bracket 4 are fixedly connected to the mounting plane 41 on a pair of diagonals. By utilizing the geometric property that the diagonal of a quadrilateral is the longest straight line, a stable support baseline is established, which improves the overall rigidity of the secondary mirror support system and enables it to better resist deformation.

[0083] The secondary mirror support 4 adopts a long, rod-shaped structure with a hollow section 42. While ensuring structural strength, it reduces the area of ​​the support's solid parts that obstructs the incident and reflected light paths, helping to reduce light energy loss caused by the support blocking light. At the same time, the hollow design also reduces the weight of the support itself, meeting the lightweight design requirements of spacecraft components.

[0084] Mounting plane 41 provides a robust mechanical interface for secondary mirror support 4. The diagonal fixing method, combined with the rod-like structure with cutouts 42, helps the secondary mirror support 4 to disperse and release internal stress caused by assembly stress or temperature changes, thereby reducing the risk of secondary mirror 3 shifting position due to external forces or thermal stress and maintaining the precise spatial position of secondary mirror 3 relative to primary mirror 1.

[0085] In summary, the embodiments of the present invention provide a stable support structure for the secondary mirror through the combination design of the mounting plane, the bracket with the hollow part, and the diagonal connection, while providing solutions for reducing light shading and maintaining alignment accuracy.

[0086] In one embodiment, the secondary mirror and the secondary mirror support are fixed together by a threaded connector with an anti-loosening structure.

[0087] By setting anti-loosening structures (such as anti-loosening nuts, locking agents, etc.) at the threaded connection, the loosening of the threaded pair that may be caused by the severe vibration during the launch phase of the spacecraft and the temperature alternation environment during operation in orbit can be effectively suppressed, providing a long-term stable mechanical connection between the secondary mirror 3 and the secondary mirror support 4, and preventing the positional displacement of the secondary mirror 3 caused by loosening of the connection.

[0088] The threaded connection allows for precise adjustment and calibration of the pitch and yaw angles of the secondary mirror during assembly by controlling the tightening torque. This adjustability helps to achieve precise alignment of the optical working surface of the secondary mirror 3 with respect to the primary mirror 1 and the optical funnel 6, providing process assurance for establishing and maintaining a precise secondary reflection optical path.

[0089] In addition, as a detachable rigid connection, threaded connections provide sufficient fastening force to ensure structural integrity, while also offering convenience for possible disassembly, maintenance, or replacement compared to permanent connection methods such as bonding or welding.

[0090] In summary, the embodiments of the present invention, by adopting a threaded connection method with an anti-loosening structure, achieve synergistic improvement in connection reliability, assembly adjustability, and maintenance convenience, providing an effective guarantee for the long-term positional stability of the secondary mirror in space environment applications.

[0091] In one embodiment, the light funnel is machined from aluminum alloy, and its inner surface is provided with a reflective medium film.

[0092] The conical cavity of the optical funnel guides the secondary reflected light from the secondary mirror to the solar cell, and its internal geometry and surface quality affect the light transmission effect. Manufacturing the optical funnel using aluminum alloy and a machining process allows for lightweight design while ensuring the necessary structural rigidity and geometric accuracy of the cavity. This process facilitates high dimensional accuracy and surface finish of the cavity, providing the necessary conditions for precise light guidance.

[0093] The reflective dielectric film coated on the inner surface of the light funnel, prepared by physical vapor deposition, effectively reduces energy loss due to multiple reflections of light within the conical cavity, thereby improving the efficiency of light transmission to the solar cell. Simultaneously, this high reflectivity reduces light absorption, helping to minimize the temperature rise of the light funnel itself due to heat absorption and reducing its burden on the system's thermal management.

[0094] In addition, the reflective medium film has a certain barrier effect against space environment factors such as atomic oxygen, which can provide surface protection for aluminum alloy substrates, slow down their surface oxidation, and maintain the long-term stability of the optical performance of the inner surface of the light funnel.

[0095] In summary, the embodiments of the present invention achieve synergistic optimization in terms of lightweight structure, light energy transmission efficiency, and environmental adaptability by comprehensively designing the material selection, molding process, and internal surface optical treatment of the light funnel, thus providing a reliable guarantee for the long-term stable operation of the focusing module.

[0096] In one embodiment, the heat spreader is an aluminum nitride heat spreader with a layer of thermally conductive interface material on its surface.

[0097] The selected thermal interface materials include aerospace-grade thermally conductive grease, gel, or phase change thermally conductive thin films. Microscopic gaps exist at the contact surfaces between the heat spreader, the solar cell, and the primary mirror substrate. Applying a layer of thermally conductive interface material to these surfaces fills these gaps, reduces contact thermal resistance, and achieves thermal coupling between the heat spreader, the solar cell, and the primary mirror substrate, improving the consistency of thermal diffusion. Simultaneously, this thermally conductive interface material possesses a certain degree of flexibility, capable of absorbing micron-level warping deformation caused by space thermal cycling, avoiding increased thermal resistance due to rigid contact.

[0098] Aluminum nitride was chosen as the material for the heat spreader primarily based on the following properties: 1) In terms of thermal conductivity, aluminum nitride has high thermal conductivity, which can quickly diffuse the high-density heat flow generated by the solar cell laterally to the entire heat spreader and even the main mirror substrate connected to it, avoiding the formation of local high-temperature hot spots under the solar cell and providing a uniform temperature distribution working environment for the solar cell.

[0099] 2) In terms of electrical insulation performance, aluminum nitride, as a ceramic material, inherently possesses electrical insulation properties, allowing it to directly contact the electrical connection points of the solar cell without the need for an additional insulation layer. This characteristic simplifies structural design, avoids introducing additional thermal resistance due to the addition of an insulation layer, and achieves a balance between electrical isolation and efficient thermal conduction.

[0100] 3) Regarding thermal expansion matching, the coefficient of thermal expansion of aluminum nitride is well-matched with that of commonly used solar cell materials, which helps reduce interfacial stress caused by differences in thermal expansion during temperature cycling. The use of surface thermally conductive interface materials further improves the distribution of interfacial stress and enhances the long-term stability of the interface under space thermal cycling conditions.

[0101] 4) In terms of weight control, aluminum nitride material has a moderate density while ensuring good thermal conductivity, which helps to control the weight of the heat spreader components. Combined with its direct mounting characteristics, it supports the compact and lightweight design of the focusing module.

[0102] In summary, the embodiments of the present invention, by selecting aluminum nitride material and combining it with the application of thermally conductive interface materials, have achieved comprehensive improvements in reducing contact thermal resistance, optimizing heat diffusion, maintaining electrical insulation, improving thermal matching, and achieving lightweighting, thus establishing a stable and reliable thermal management interface for the focusing module.

[0103] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A space-based light-concentrating module, characterized in that, Includes primary mirror, secondary mirror, secondary mirror support, optical funnel, solar cells, and heat spreader; The primary mirror includes a primary mirror base, which forms the sun-facing opening of the light-concentrating module. Its optical working surface is set towards the secondary mirror for receiving and reflecting incident sunlight. The secondary mirror is fixed above the primary mirror by the secondary mirror bracket and is located in the convergence area of ​​the reflected light path of the primary mirror. Its optical working surface faces the entrance of the light funnel and is used to perform secondary reflection of the light reflected by the primary mirror. The light funnel has a conical cavity structure, with its inlet receiving the reflected light path of the secondary mirror and its outlet corresponding to the light-receiving surface of the solar cell, and is used to guide the light reflected by the secondary mirror to the solar cell. The battery cell is positioned below the light path outlet of the light funnel and is used to convert light energy into electrical energy. The heat-dissipating plate is tightly attached between the back of the battery cell and the primary mirror substrate, and is used to conduct the heat generated by the battery cell during operation to the primary mirror substrate; wherein... The primary mirror substrate also serves as a heat dissipation element for the light-concentrating module, radiating the heat conducted from the heat spreader to the space environment via its surface.

2. The concentrating module according to claim 1, characterized in that, The primary mirror substrate adopts a near-parabolic spherical structure with a quadrilateral outline; Its concave surface serves as the optical working surface, and a reflective layer and a transparent infrared radiation layer covering the reflective layer are provided in sequence. The transparent infrared radiation layer is used to radiate the heat absorbed by the primary mirror substrate into the space environment in the form of infrared radiation.

3. The focusing module according to claim 2, characterized in that, The transparent infrared radiation layer comprises a transparent polymer matrix, and modified SiO2 nanoparticles, modified ZrO2 nanoparticles, and boron nitride nanosheets dispersed in the matrix. Based on 100 parts by weight of the transparent polymer matrix, the amount of modified SiO2 nanoparticles added is 0.1-5 parts, the amount of modified ZrO2 nanoparticles added is 0.1-3 parts, and the amount of boron nitride nanosheets added is 0.1-2 parts.

4. The focusing module according to claim 3, characterized in that, The modified ZrO2 nanoparticles are doped with MgO, with the doping amount of MgO being 0.01-2 mol.

5. The concentrating module according to claim 3, characterized in that, The modified SiO2 nanoparticles have an average particle size of 5-30 nm; the modified ZrO2 nanoparticles have an average particle size of 10-50 nm.

6. The concentrating module according to claim 3, characterized in that, The boron nitride nanosheets have a lateral dimension of 1-50 nm and a thickness of 1-50 nm.

7. The concentrating module according to claim 3, characterized in that, Both the modified SiO2 nanoparticles and the modified ZrO2 nanoparticles have undergone surface modification with a silane coupling agent.

8. The condensing primary lens according to any one of claims 3-7, characterized in that, The thickness of the infrared radiation layer is 10-30 μm.

9. The concentrating module according to claim 2, characterized in that, The convex surface of the primary mirror substrate is provided with a thermally conductive radiation layer, which is a graphene film, used to diffuse the heat absorbed by the primary mirror substrate laterally and radiate it into the space environment.

10. The focusing module according to claim 2, characterized in that, The concave center of the primary mirror substrate is provided with a positioning groove; the battery is placed directly above the positioning groove, and the heat-dissipating sheet is placed inside the positioning groove.

11. The concentrating module according to claim 2, characterized in that, The primary mirror base has mechanical mounting surfaces at its four apex corners; The secondary mirror support adopts a long strip-shaped rod structure with a hollowed-out part; the two ends of the secondary mirror support are respectively fixedly connected to the two mounting planes on a diagonal line of the primary mirror base.

12. The concentrating module according to claim 2, characterized in that, The secondary mirror has a near-hyperboloid surface structure, with a reflective medium film on its optical working surface and a heat dissipation coating on its non-optical working surface.

13. The concentrating module according to claim 1, characterized in that, The secondary mirror and the secondary mirror bracket are fixed together by a threaded connector with an anti-loosening structure.

14. The concentrating module according to claim 1, characterized in that, The light funnel is machined from aluminum alloy, and its inner surface is provided with a reflective medium film.

15. The concentrating module according to claim 1, characterized in that, The heat spreader is made of aluminum nitride and its surface is coated with a layer of thermally conductive interface material.

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