Double-layer interface-free light-trapping coating and its preparation method, battery module and manufacturing method

Abstract

This invention provides a double-layer interface-free light-trapping coating and its preparation method, as well as a battery module and manufacturing method, relating to the field of solar cell manufacturing technology. The method includes: printing a substrate layer; pre-curing; printing a structural layer; and main curing. In the prepared double-layer interface-free light-trapping coating, the substrate layer is printed using UV ink with a predetermined refractive index, providing optical anti-reflection and anti-reflection properties. The structural layer has a three-dimensional structure, providing excellent light-trapping effects. Simultaneously, the structural layer is also printed using UV ink with the same refractive index as the substrate layer, and the substrate layer and structural layer have an integrated, interface-free structure, effectively combining the anti-reflection and anti-reflection properties of the substrate layer with the light-trapping properties of the structural layer, achieving a dual effect of "anti-reflection" and "light-trapping." This effectively improves the power output of solar cell modules and has advantages such as high precision, stable structure, simple preparation process, short process, and low equipment investment.

Description

Technical Field

[0001] This invention relates to the field of solar cell manufacturing technology, and in particular to a double-layer interface-free light-trapping coating and its preparation method, as well as a cell module and its manufacturing method. Background Technology

[0002] Solar cell modules are one of the core components of a solar photovoltaic power generation system. A typical solar cell module, from top to bottom, includes: glass, encapsulating film, solar cell, encapsulating film again, and backsheet. Before reaching the solar cell, incident light passes through multiple layers of media, and reflection and refraction occur at each interface (e.g., air-glass interface, glass-encapsulating film interface, encapsulating film-solid cell interface). To minimize light loss at these interfaces and improve the utilization rate of incident light, a silicon nitride (SiNx) antireflective coating with a refractive index of approximately 1.9-2.1 is typically fabricated on the front side of the solar cell to match the refractive index of the solar cell (n approximately 3.5) and the encapsulating film (n approximately 1.48). Physical textured structures can also be formed on the surface of solar cells through etching. For example, alkaline etching creates a micro-nano pyramid texture on the surface of monocrystalline silicon cells, while acid etching creates a nano-scale pitted texture on the surface of polycrystalline silicon cells. These physical textured structures reduce reflectivity by increasing the number of reflections of light on the cell surface, thus trapping light.

[0003] The aforementioned SiNx antireflective coating only serves to reduce reflection, and the physical light-trapping structure only serves to trap light. Furthermore, when used simultaneously, they do not improve the optical performance of solar cell modules; instead, they mutually restrict each other. This is because the refractive index difference between the interfaces of the physical textured structure is significantly reduced after being filled with the high-refractive-index SiNx antireflective coating and encapsulating film, leading to a substantial decrease in the efficiency of its light-trapping mechanism, which relies on multiple reflections and total internal reflection. Therefore, there is an urgent need for a film layer that can both reduce reflection and trap light to improve the optical performance of solar cell modules. Summary of the Invention

[0004] The present invention aims to provide a double-layer interface-free light-trapping coating and its preparation method, as well as a battery component and its manufacturing method, in order to at least partially solve at least one of the above-mentioned technical problems.

[0005] To address the aforementioned technical problems, in a first aspect, the present invention provides a method for preparing a double-layer interface-free light-trapping coating, the method comprising: Printing the substrate layer: The substrate enters the inkjet printing station, where a planar substrate layer is printed on the substrate surface using UV ink; Pre-curing: After the planar base layer is printed, the base layer enters the pre-curing station for pre-curing, forming a solidified base layer with a surface gel layer encapsulating the internal liquid or semi-liquid. Printing structural layer: Entering the second inkjet printing station, a three-dimensional structural layer is printed on the surface of the cured substrate using UV ink; Main curing: Entering the main curing station, the curing base layer and the three-dimensional structure layer are cross-linked and cured to form a double-layer interface-free light-trapping coating.

[0006] According to a preferred embodiment of the present invention, the pre-curing process further includes: entering a low-power LED-UV pre-curing station and irradiating the substrate layer with an energy of 50-500 mj / cm2 for a predetermined time, so that the surface molecules of the substrate layer undergo preliminary cross-linking to form a surface gel layer that encapsulates the internal liquid or semi-liquid and has chemical reactivity as a cured substrate layer.

[0007] According to a preferred embodiment of the present invention, the main curing process further includes: entering a high-power main curing station and using energy of 1500-2500 mj / cm2 to irradiate and cure the substrate layer and the three-dimensional structure layer to achieve complete and uniform crosslinking curing.

[0008] According to a preferred embodiment of the present invention, the method further includes: the time interval between pre-curing and printing the structural layer is less than or equal to 2 seconds.

[0009] According to a preferred embodiment of the present invention, before printing the substrate layer, the method further includes: preparing a UV ink using the following components: Polyurethane acrylate: 20-40 parts; Trimethylolpropane triacrylate: 30-40 parts; Nano-zirconia: 30-35 parts; Photoinitiator: 2-3 parts; Leveling agent: 0.2~0.8 parts.

[0010] According to a preferred embodiment of the present invention, the preparation specifically includes: stirring the components at high speed in the dark for a period of time, grinding and dispersing them evenly with a grinder, and filtering them through a filter screen to obtain UV ink. The ink has a viscosity of 8-100 cp and a refractive index of 1.67.

[0011] According to a preferred embodiment of the present invention, the structural layer is a hemispherical microlens array, a biomimetic moth eye array, or a random three-dimensional pattern.

[0012] To solve the above-mentioned technical problems, the second aspect of the present invention provides a double-layer interface-free light-trapping coating, which is prepared using UV ink, wherein the UV ink comprises: polyurethane acrylate: 20-40 parts; trimethylolpropane triacrylate: 30-40 parts; nano-zirconia: 30-35 parts; photoinitiator: 2-3 parts; leveling agent: 0.2-0.8 parts.

[0013] According to a preferred embodiment of the present invention, the double-layer interface-free light-trapping coating is manufactured using the preparation method of the double-layer interface-free light-trapping coating described in any one of the above-mentioned methods.

[0014] To address the aforementioned technical problems, a third aspect of the present invention provides a battery assembly comprising: glass and a solar cell, wherein the glass and the solar cell are provided with the aforementioned double-layer interface-free light-trapping coating.

[0015] According to a preferred embodiment of the present invention, an adhesive film layer is provided between the glass and the double-layer interface-free light-trapping coating, and a refractive index substrate layer is provided between the double-layer interface-free light-trapping coating and the solar cell.

[0016] According to a preferred embodiment of the present invention, the thickness of the glass is 3~3.5mm, the thickness of the adhesive film layer is 0.44~0.48mm, the thickness of the double-layer interface-free light-trapping coating is 4~5µm, the thickness of the refractive index substrate layer is 2~15µm, and the thickness of the solar cell is 180~210µm.

[0017] To address the aforementioned technical problems, a fourth aspect of the present invention provides a method for manufacturing a battery module, comprising: Manufacturing solar cells; Using a solar cell as a substrate, a double-layer interface-free light-trapping coating is prepared on the light-facing surface of one or more solar cells using any of the above-described methods.

[0018] In summary, this invention employs UV ink to print a substrate layer, followed by low-power pre-curing to induce preliminary cross-linking of surface molecules, forming a chemically reactive surface gel layer that encapsulates an internal liquid or semi-liquid solidified substrate layer. Next, a three-dimensional structural layer is printed onto the surface of this solidified substrate layer using UV ink. Since the gel on the surface of the solidified substrate layer is already shaped, the printed UV ink droplets will not collapse or overspread, allowing the formation of a three-dimensional structural layer on the solidified substrate layer surface. Finally, the solidified substrate layer and structural layer are cured at high power to form a two-layer integrated, physically interface-free light-trapping coating. In the light-trapping coating prepared by this invention, the substrate layer is printed using UV ink with a predetermined refractive index, providing optical anti-reflection and anti-reflection properties. The structural layer has a three-dimensional structure, providing excellent light-trapping effects. Simultaneously, the structural layer is also printed using UV ink with the same refractive index as the substrate layer, and the substrate layer and structural layer have an integrated, physically interface-free structure. Therefore, the anti-reflection and anti-reflection properties of the substrate layer are effectively combined with the light-trapping properties of the structural layer, achieving a dual effect of "anti-reflection" and "light-trapping." It can effectively improve the power output of solar cell modules, and has the advantages of high precision, stable structure, simple manufacturing process, short process and low equipment investment. Attached Figure Description

[0019] Figure 1 This is a schematic flowchart of a method for preparing a double-layer interface-free light-trapping coating according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a battery assembly provided in an embodiment of the present invention. Detailed Implementation

[0020] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the invention.

[0021] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0022] This invention provides a method for preparing a double-layer, interface-free light-trapping coating, such as... Figure 1 As shown, the method includes: S1. Printing the base layer: The substrate enters the inkjet printing station, and a planar base layer is printed on the surface of the substrate using UV ink.

[0023] In this embodiment, a planar substrate layer is printed on the substrate surface using UV ink; wherein: the substrate can be a device with the double-layer interface-free light-trapping coating prepared in this invention as a component, such as a solar cell; or it can be a device specifically used to prepare the double-layer interface-free light-trapping coating; this invention does not make specific limitations.

[0024] The UV ink is prepared using polyurethane acrylate, trimethylolpropane triacrylate (TMPTA), nano-zirconia, photoinitiator, and leveling agent.

[0025] In one possible implementation, the mass ratio of polyurethane acrylate, trimethylolpropane triacrylate, nano-zirconia, photoinitiator, and leveling agent is (20~40):(30~40):(30~35):(2~3):(0.2~0.8). The preferred mass ratio of each component is 30:35:32:2.5:0.5. Wherein, the weight-average molecular weight (Mw) of the polyurethane acrylate is 5500~6500, preferably Mw=6000, and the median diameter (D50) of the nano-zirconia is 20~40 nm, preferably D50=30. The photoinitiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (abbreviated TPO), and the leveling agent is a polyether-modified polydimethylsiloxane solution (e.g., BKY-333). For example, the above components can be stirred at high speed (e.g., stirring speed greater than or equal to 300 rpm) for 1-3 hours (e.g., 2 hours) under light-protected conditions, ground until uniformly dispersed, and filtered to obtain UV ink with a viscosity of 8-100 CP at printing temperature (40-60℃). (For example, grinding with a three-roll mill and filtering with a 200nm filter yields UV ink with a viscosity of 12 cP). This ensures smooth inkjet printing and proper droplet spreading after printing, and a UV ink with a refractive index of 1.67 after curing. In this example, the required viscosity and refractive index of the UV ink can be obtained by adjusting parameters such as the mass ratio of each component, stirring time, stirring speed, and filtration accuracy. The viscosity of the ink at a printing temperature of 40-60℃ is strictly controlled between 8-100 CP to ensure smooth inkjet printing and proper leveling of ink droplets after printing.

[0026] In one possible implementation, this step can transfer the substrate (such as an n-type BC cell) to the first inkjet printing station and print a flat, planar substrate layer with a thickness of 8µm using a piezoelectric printhead (liquid volume 13pL).

[0027] S2, Pre-curing: After the planar base layer is printed, the base layer enters the pre-curing station for pre-curing, forming a surface gel layer that encapsulates the internal liquid or semi-liquid cured base layer. In this embodiment, a low-power UV curing device is used to pre-cur the substrate layer to allow initial cross-linking of the surface molecules, forming a cured substrate layer with a surface gel layer encapsulating the internal liquid or semi-liquid. The surface of this cured substrate layer is a gel layer with a thickness less than a predetermined thickness, and this gel layer encapsulating the internal liquid or semi-liquid gives it chemical reactivity. The predetermined thickness must meet the requirements for chemical reactivity; for example, the predetermined thickness could be 0.1 µm. The low power can be any power value less than a first preset power, which can be set according to actual needs; for example, the first preset power could be 4 W / cm².

[0028] In one possible implementation, after the substrate layer is printed, the substrate is immediately placed in a low-power 395nm LED-UV pre-curing station to receive 50-500 mJ / cm². 2 The substrate is pre-cured for a predetermined time by irradiating it with energy. Specifically, the energy needs to be precisely controlled between 50-500 mJ / cm². 2 Within this range, on the one hand, it can avoid the phenomenon that the gel layer cannot be formed on the surface of the solidified substrate due to insufficient energy, resulting in the solidified substrate still being liquid, which would cause the subsequent printed structural layer to collapse; on the other hand, it can avoid the phenomenon that the gel layer on the surface of the solidified substrate is too thick due to excessive energy, resulting in over-curing, which would reduce the adhesion of the subsequent printed structural layer and make it difficult to form an interface-free structure between the solidified substrate and the structural layer.

[0029] In practice, the power and irradiation time of the LED-UV curing station can be controlled to ensure that the energy is kept between 50-500 mJ / cm². 2 Within a certain range. For example, the substrate can be cured at 200 mJ / cm² in a 395 nm LED-UV curing station. 2 Pre-curing is achieved by irradiating the material with energy for 0.8 seconds.

[0030] S3, Printing structural layer: Entering the second inkjet printing station, a three-dimensional structural layer is printed on the surface of the cured substrate layer using UV ink; In this embodiment, the time interval between steps S2 and S3 must be less than or equal to 2 seconds. That is, the time interval from the completion of pre-curing in step S2 to the start of printing the structural layer in step S3 must be less than or equal to 2 seconds. This ensures that the active groups inside the cured substrate layer remain highly active and can form sufficient chemical bonds with the UV ink of the structural layer.

[0031] The structural layer has excellent light-trapping effect due to its three-dimensional structure, which can be generated by pre-designing a microstructure model; for example, the structural layer can be a hemispherical microlens array, a biomimetic moth eye array, or a random three-dimensional pattern generated by a computer program or user instructions.

[0032] In one possible implementation, this step involves feeding the substrate (e.g., a battery cell) into a second inkjet printing station. The inkjet printer then prints a hemispherical microlens array consisting of hemispherical microlenses with a diameter of 20µm and a height of 5µm onto the already "pinned" solidified substrate layer. Since a solidified substrate layer with a surface gel layer encapsulating an internal liquid or semi-liquid layer is formed in step S2, and this surface gel layer is already shaped, the UV ink droplets printed on it in this step will neither collapse nor spread excessively, ensuring the printing effect of the structural layer. Preferably, before printing, the initial printing position of the printing equipment can be aligned with the initial position of the solidified substrate layer (e.g., edges, vertices, etc.), and the alignment accuracy (i.e., the alignment between the second layer and the first layer) can be controlled within ±10µm to ensure the structural integrity of the three-dimensional structural layer.

[0033] S4. Main Curing: Entering the main curing station, the curing base layer and the three-dimensional structure layer are cross-linked and cured to form a double-layer interface-free light-trapping coating.

[0034] This step requires the use of high-power UV curing equipment to cure the substrate layer and structural layer, ensuring complete and uniform cross-linking and curing of this dual-layer structure to form a chemically bonded, interface-free, integrated dual-layer light-trapping coating. The high power can be any value greater than a second preset power, which can be set according to actual needs; for example, the second preset power could be 8 W / cm².

[0035] In one possible implementation, after printing the 3D structural layers, the substrate (such as a solar cell) is immediately placed in a high-power 365nm+395nm LED-UV main curing station to receive 1800~2500mJ / cm². 2 The substrate and structural layers are cured by irradiation with energy; preferably 2000 mJ / cm. 2 The energy is used to irradiate the base layer and structural layer to cure them.

[0036] In practice, the power and irradiation time of the LED-UV curing station can be controlled to ensure that the energy is kept between 1800 and 2500 mJ / cm². 2 That's possible. For example, the substrate and structural layers can be cured at 2000 mJ / cm² in a 365nm+395nm LED-UV curing station. 2 It was cured by irradiating it with energy for 2 seconds.

[0037] In the actual preparation process, the surface tension of the UV ink can be optimized by adjusting the component ratio, stirring time, and filtration accuracy of the UV ink within the range of the above process parameters. The main curing parameters can be optimized by adjusting the main curing energy, power, and time. Combined with optimizing the pre-curing timing, this ensures that the morphological fidelity of the microstructure of the light-trapping coating formed by the final curing is greater than 95% with that of the pre-designed microstructure model.

[0038] based on Figure 1 The present invention provides a method for preparing a double-layer interface-free light-trapping coating, and the following specific embodiments are provided: Example 1: Using 30 parts of polyurethane acrylate, 35 parts of trimethylolpropane triacrylate, 32 parts of 32wt% nano-zirconia particles modified with KH-570, 2.5 parts of photoinitiator, and 0.5 parts of leveling agent, the mixture was stirred at 350 rpm for 2 hours under light-protected conditions until uniformly dispersed and filtered to obtain UV ink. An 8μm planar substrate layer was printed on the substrate surface using this UV ink, and pre-cured with a low-power 395nm LED-UV curing station at 100mJ / cm² energy to obtain a cured substrate layer. A 5μm high hemispherical microlens array structure layer was printed on the cured substrate layer using this UV ink. The substrate was then pre-cured with a high-power 365nm+395nm LED-UV curing station at 2000mJ / cm² energy to obtain a double-layer interface-free light-trapping coating.

[0039] Example 2: Same as Example 1, except that the base layer thickness is 5μm and the structural layer is printed with a 10μm high biomimetic moth eye array.

[0040] Example 3: Same as Example 1, except that the structural layer is printed with a 4μm high computer-generated random 3D texture.

[0041] Example 4: Same as Example 1, except that the nano ZrO2 in the UV ink is replaced with an equal amount of nano HfO2 to verify the universality of the material.

[0042] Example 5: Same as Example 1, except that the pre-curing energy is increased to 120mJ / cm², and the main curing energy is reduced to 1800mJ / cm², in order to verify the width of the process window.

[0043] In addition, to verify the performance of the double-layer interface-free light-trapping coating prepared by the above method, the present invention also provides the following comparative examples: Comparative Example 1: n-type BC solar cells, without any coating, are directly encapsulated with standard EVA film.

[0044] Comparative Example 2: Same as Example 1, except that only an 8μm thick base layer was printed, and then the main curing was performed directly without printing the structural layer.

[0045] Comparative Example 3: Same as Example 1, except that the "pre-curing" step is skipped, that is, the substrate layer is not pre-cured, and the main curing is performed directly after the substrate layer and structural layer are printed.

[0046] Comparative Example 4: Same as Example 1, except that the pre-curing energy is 600 mJ / cm². 2 Excessive pre-curing.

[0047] The double-layer interface-free light-trapping coatings prepared in Examples 1-5 and the coatings prepared in Comparative Examples 1-3 were used as encapsulation materials between solar cells and glass. The performance test results are shown in Table 1.

[0048] In Table 1: Pmax gain refers to the increase in the maximum output power Pmax of the battery module relative to the baseline value. IAM factor (@60°) refers to the IAM (Incidence Angle Modifier) ​​factor of the battery module at an incident angle of 60°. Structural fidelity refers to the ability of the coating to maintain its preset chemical structure, crystal structure, or microstructure during the preparation process. TC200 adhesion refers to the ability of the coating to maintain its strong bond with the substrate (or between coatings) after contact with a specific organic solvent. As can be seen from Table 1, the double-layer interface-free light-trapping coating prepared in this invention is superior to the comparative example in terms of Pmax gain, structural fidelity, and adhesion, especially with a significant improvement in Pmax gain, proving that the double-layer interface-free light-trapping coating prepared in this invention can effectively improve the power output of solar cell modules.

[0049] Based on the above-mentioned method for preparing a double-layer interface-free light-trapping coating, this embodiment of the invention also provides a double-layer interface-free light-trapping coating, which is prepared using UV ink. The UV ink comprises: 20-40 parts of polyurethane acrylate; 30-40 parts of trimethylolpropane triacrylate; 30-35 parts of nano-zirconia; 2-3 parts of photoinitiator; and 0.2-0.8 parts of leveling agent.

[0050] In one possible implementation, the double-layer interface-free light-trapping coating is prepared by any one of the above-described methods for preparing a double-layer interface-free light-trapping coating.

[0051] For example, the dual-layer interface-free light-trapping coating may include: a planar substrate layer and a structural layer without a physical interface, both of which are printed using UV ink with a predetermined refractive index (e.g., 1.67), and the structural layer has a three-dimensional structure. In this light-trapping coating, the substrate layer is printed using UV ink with a predetermined refractive index, providing optical anti-reflection and anti-reflection properties; the structural layer has a three-dimensional structure, providing excellent light-trapping effect. Simultaneously, the structural layer is also printed using UV ink with the same refractive index as the substrate layer, and there is no physical interface between the substrate layer and the structural layer. Therefore, the anti-reflection and anti-reflection properties of the substrate layer can be effectively combined with the light-trapping properties of the structural layer, achieving the dual effects of "anti-reflection" and "light-trapping".

[0052] The substrate layer has a thickness of 5-10 μm, and the structural layer has a thickness of 3-8 μm. The structural layer can be a hemispherical microlens array, a biomimetic moth-eye array, or a random three-dimensional pattern generated by a computer program or user instructions. Taking a hemispherical microlens array as an example, it can consist of multiple hemispherical microlenses with a diameter of 20 µm and a height of 5 µm. The thickness of the structural layer refers to the vertical length from the lowest point to the highest point within the structural layer. For example, the height of the hemispherical microlenses in the structural layer of a hemispherical microlens array is the thickness of that structural layer.

[0053] The UV ink comprises: 20-40 parts of polyurethane acrylate; 30-40 parts of trimethylolpropane triacrylate; 30-35 parts of nano-zirconia; 2-3 parts of photoinitiator; and 0.2-0.8 parts of leveling agent. The UV ink has a viscosity of 8-100 CP and a refractive index of 1.67 at a printing temperature (40-60℃).

[0054] Based on the above-described method for preparing a double-layer interface-free light-trapping coating, this invention provides a battery component, such as... Figure 2 As shown, it includes: solar cell 21 and glass 22, with a double-layer interface-free light-trapping coating 23, as described above, filling the space between the light-facing surface of the solar cell 21 and the glass 22. Multiple solar cells 21 can be connected in series to form a battery string. These battery strings can be connected in series, in parallel, or in a series-parallel combination to achieve current collection and output. For example, the connection between individual solar cells can be achieved by welding ribbons, or the connection between battery strings can be achieved by busbars.

[0055] In one possible implementation, such as Figure 2As shown, the battery assembly may further include an encapsulant layer 24 and a refractive index substrate layer 25. The encapsulant layer 24 can be filled between the double-layer interface-free light-trapping coating 23 and the glass 22. The encapsulant layer 24 can be a transparent colloid with good light transmittance and aging resistance, such as EVA film or POE film. The specific choice can be made according to the actual situation and is not limited here. The refractive index substrate layer 25 can be filled between the double-layer interface-free light-trapping coating 23 and the light-facing surface of the solar cell 21. The refractive index substrate layer 25 can be a transparent colloid with good light transmittance and a refractive index between that of the solar cell 21 (n is approximately 3.5) and the encapsulant layer 24 (n is approximately 1.48). For example, the refractive index substrate layer 25 can be a POE film. The specific choice can be made according to the actual situation and is not limited here. For example, the solar cell 21 may be a silicon cell with a thickness of 180-210µm, the refractive index substrate layer 25 has a thickness of 2-15µm, the double-layer interface-free light-trapping coating 23 has a thickness of 4-5µm, the encapsulant layer 24 has a thickness of 0.46mm, and the glass 22 may be tempered glass with a thickness of 3.2mm.

[0056] In one possible implementation, the solar cell module may further include a metal frame and a backsheet. The encapsulant layer 24 may further fill the space between the back surface of the solar cell 21, the backsheet, and adjacent cells.

[0057] Based on the above-described method for preparing a double-layer interface-free light-trapping coating, this invention also provides a method for manufacturing a solar cell module, the method comprising: S101, Manufacturing solar cells; This step can be accomplished using existing processes to manufacture solar cells (such as n-type BC cells, PERC cells, TOPCon cells, and HJT cells), and will not be elaborated further here.

[0058] S102. Using a solar cell as a substrate, a double-layer interface-free light-trapping coating is fabricated on the light-facing surface of one or more of the solar cells using any one of the above-described methods for preparing a double-layer interface-free light-trapping coating.

[0059] In summary, the double-layer interface-free light-trapping coating and its preparation method, as well as the battery module and manufacturing method provided by this invention, utilize UV ​​ink with a predetermined refractive index for the substrate layer, providing optical anti-reflection and anti-reflection properties. The structural layer has a three-dimensional structure, providing excellent light-trapping effects. Furthermore, the structural layer is also printed using UV ink with the same refractive index as the substrate layer, and the substrate layer and structural layer have an integrated, interface-free structure. Therefore, the anti-reflection and anti-reflection properties of the substrate layer can be effectively combined with the light-trapping properties of the structural layer, achieving a dual effect of "anti-reflection" and "light-trapping." This effectively improves the power output of solar cell modules and has advantages such as high precision, stable structure, simple preparation process, short process, and low equipment investment. Compared with the prior art, this invention has at least the following beneficial effects: 1. This invention uses UV ink with preset viscosity and refractive index to print a planar substrate layer and pre-cures it before printing a three-dimensional structure layer on its surface. The two are then cured to form a light-trapping coating with a double-layer integrated structure, no physical interface defects, and a gradient refractive index, thereby achieving the effect of both trapping light and reducing reflection.

[0060] 2. This invention uses inkjet printing and curing technology to achieve the manufacturing of high-precision, structurally stable, and flexible coatings, which has the advantages of simple process, convenient operation and low manufacturing cost; at the same time, it can be seamlessly integrated with existing production lines.

[0061] 3. The double-layer interface-free light-trapping coating manufactured by this invention is designed for an adhesive film environment, which has extremely high structural fidelity and adhesion after TC200, and excellent encapsulation performance.

[0062] It should be clarified that the present invention is not limited to the specific structures and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known structures are omitted here. In the above embodiments, several specific structures are described and shown as examples. However, the lens cleaning device of the present invention is not limited to the specific structures described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the installation positions between structures, after understanding the spirit of the present invention.

[0063] The above description is merely a specific embodiment of the present invention. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the structures, modules, and units described above can be referred to the corresponding processes in the foregoing embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A method for preparing a double-layer interface-free light-trapping coating, characterized in that, include: Printing the substrate layer: The substrate enters the inkjet printing station, where a planar substrate layer is printed on the substrate surface using UV ink; Pre-curing: After the planar base layer is printed, the base layer enters the pre-curing station for pre-curing, forming a solidified base layer with a surface gel layer encapsulating the internal liquid or semi-liquid. Printing structural layer: Entering the second inkjet printing station, a three-dimensional structural layer is printed on the surface of the cured substrate using UV ink; Main curing: Entering the main curing station, the curing base layer and the three-dimensional structure layer are cross-linked and cured to form a double-layer interface-free light-trapping coating.

2. The method according to claim 1, characterized in that, Pre-curing specifically includes: entering a low-power LED-UV pre-curing station, using 50-500mj / cm². 2 The energy irradiates the substrate layer for a predetermined time, causing the surface molecules of the substrate layer to undergo initial cross-linking, forming a surface gel layer that encapsulates the internal liquid or semi-liquid, and is a chemically reactive solidified substrate layer.

3. The method according to claim 1 or 2, characterized in that, The main curing process specifically includes: entering a high-power main curing station, using 1500-2500 mJ / cm². 2 The energy irradiation cures the substrate layer and the three-dimensional structure layer to achieve complete and uniform cross-linking and curing.

4. The method according to claim 1, characterized in that, Also includes: The time interval between pre-curing and printing the structural layer is less than or equal to 2 seconds.

5. The method according to claim 1, characterized in that: Prior to printing the substrate layer, the method further includes preparing a UV ink using the following components: Polyurethane acrylate: 20-40 parts; Trimethylolpropane triacrylate: 30-40 parts; Nano-zirconia: 30-35 parts; Photoinitiator: 2-3 parts; Leveling agent: 0.2~0.8 parts.

6. The method according to claim 5, characterized in that, The preparation process specifically includes: stirring the components at high speed in the dark for a period of time, grinding and dispersing them evenly with a grinder, and filtering them through a filter screen to obtain UV ink. The ink has a viscosity of 8-100 cp and a refractive index of 1.

67.

7. The method according to claim 1, characterized in that, The structural layer consists of a hemispherical microlens array, a biomimetic moth-eye array, or a random three-dimensional pattern.

8. A double-layer interface-free light-trapping coating, characterized in that, The UV ink is prepared using UV ink, which includes: 20-40 parts of polyurethane acrylate; 30-40 parts of trimethylolpropane triacrylate; 30-35 parts of nano-zirconia; 2-3 parts of photoinitiator; and 0.2-0.8 parts of leveling agent.

9. The double-layer interface-free light-trapping coating according to claim 8, characterized in that, It is manufactured using the method described in any one of claims 1-4, 6.

10. A battery assembly, comprising: Glass and solar cell, characterized in that a double-layer interface-free light-trapping coating as described in claim 8 or 9 is provided between the glass and the solar cell.

11. The battery assembly according to claim 10, characterized in that, An adhesive film layer is provided between the glass and the double-layer interface-free light-trapping coating, and a refractive index substrate layer is provided between the double-layer interface-free light-trapping coating and the solar cell.

12. The battery assembly according to claim 11, characterized in that, The thickness of the glass is 3~3.5mm, the thickness of the adhesive film layer is 0.44~0.48mm, the thickness of the double-layer interface-free light-trapping coating is 4~5µm, the thickness of the refractive index substrate layer is 2~15µm, and the thickness of the solar cell is 180~210µm.

13. A method for manufacturing a battery module, characterized in that, include: Manufacturing solar cells; Using a solar cell as a substrate, a double-layer interface-free light-trapping coating is prepared on the light-facing surface of one or more solar cells using the double-layer interface-free light-trapping coating preparation method described in any one of claims 1-7.

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