Composition for transfer printing, preparation method of composition and preparation method of electrode grid line

Abstract

The invention relates to a composition for transfer printing, a preparation method thereof and an electrode grid line preparation method, and relates to the technical field of photovoltaic cell manufacturing, and the composition for transfer printing comprises the following components by weight: 6-40% of polyvinyl alcohol; 0.05-5% of a plasticizer; 3-20% of a coalescing agent; 0.05 to 5% of a surfactant; 1-20% of a hydrophilic material; 0.01%-0.5% of a release agent; 0.01 to 1 percent of a flatting agent; 0.01 to 1 percent of a defoaming agent; and the balance of water. Through reasonable component proportion, the defects of an existing water-soluble film are optimized, and the dissolution speed, the environmental protection property, the mechanical property and the compatibility with a silicon wafer or conductive slurry of the water-soluble film are improved; by adding the surfactant, the hydrophilic material, the plasticizer and the coalescing agent, the flexibility, the tear resistance and the water solubility of the film are improved, so that the film has better mechanical properties, the defect of the traditional PVA film in the aspect of dissolution rate is overcome, and the quick water solubility, the good mechanical properties and the environmental protection property of the film are realized; and the transfer printing effect of the thin film and the adaptability of the thin film to a silicon wafer can be improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic cell manufacturing technology, and in particular to a composition for transfer printing, a preparation method thereof, and an electrode grid line preparation method. Background Art

[0002] In photovoltaic cell production, grid lines are responsible for collecting and conducting current, directly impacting the photoelectric conversion efficiency and long-term stability of the cell. Currently, grid lines are primarily fabricated using screen printing and electroplating, but each method has its own limitations.

[0003] Screen printing is a commonly used fabrication process, but its precision is limited by the mesh size of the screen, making it difficult to achieve more refined gridline designs, especially given the increasing demand for gridline precision in high-efficiency photovoltaic cells. Furthermore, the conductive paste waste during the printing process is significant and cannot be fully recovered, leading to increased production costs. Furthermore, screen templates are prone to wear and tear after frequent use, requiring regular replacement, which not only increases production costs but also reduces production efficiency.

[0004] Electroplating offers high precision, but the process is complex, requiring strict control of multiple parameters such as the plating solution composition, temperature, and current density. This makes the process challenging and places high demands on equipment stability. During the electroplating process, the plating solution often contains hazardous substances such as heavy metals, which can pollute the environment if not handled properly. Furthermore, the electroplating process can damage the silicon wafer surface, impacting the performance and lifespan of photovoltaic cells.

[0005] To solve the above problems, some studies have attempted to use water-soluble films as carriers for preparing electrode grid lines. However, the dissolution time of existing water-soluble films at room temperature is too long to meet the needs of rapid production, affecting production efficiency. At the same time, some film materials contain harmful ingredients, which pose potential risks to the environment and human health. In addition, adverse chemical reactions may occur between water-soluble films and silicon wafers or conductive pastes, affecting the conductive properties of photovoltaic cells or the surface properties of silicon wafers. The mechanical properties of the film are also poor, and it is easy to deform or break during the transfer process, and the accuracy and integrity of the grid line pattern cannot be guaranteed.

[0006] Therefore, how to overcome the shortcomings of existing technologies and improve the accuracy, efficiency and environmental friendliness of electrode grid line preparation has become an urgent problem to be solved in the current photovoltaic cell production. Summary of the Invention

[0007] In order to solve the problems that existing water-soluble films will chemically react with silicon wafers or conductive pastes, and that the films take a long time to dissolve in water, have poor environmental protection, and have poor mechanical properties, the present application provides a composition for transfer, a preparation method thereof, and an electrode grid line preparation method.

[0008] The following technical solutions are adopted: A composition for transfer printing comprises the following components in weight percentage: polyvinyl alcohol: 6-40%; plasticizer: 0.05-5%; film-forming aid: 3-20%; surfactant: 0.05-5%; hydrophilic material: 1-20%; release agent: 0.01-0.5%; leveling agent: 0.01-1%; defoaming agent: 0.01-1%; and balance water.

[0009] By adopting the above technical solution and through a reasonable ratio of ingredients, the present application optimizes the shortcomings of the existing water-soluble film, improves its dissolution speed, environmental protection, mechanical properties and compatibility with silicon wafers or conductive pastes, and the optimized film can dissolve quickly, ensuring compatibility with silicon wafers or conductive pastes, and has excellent mechanical properties, ensuring transfer accuracy and environmental protection; surfactants, hydrophilic materials, plasticizers and film-forming aids are added to improve the flexibility, tear resistance and water solubility of the film, so that it has better mechanical properties, solves the shortcomings of traditional PVA film in dissolution speed, and achieves rapid water solubility, good mechanical properties and environmental protection of the film, making it more uniform and rapid when dissolved in water, and helping to improve the transfer effect of the film and its compatibility with silicon wafers; in addition, after adding a release agent, a leveling agent and a defoaming agent, the demoulding property, surface smoothness and uniformity of the film are significantly improved. The release agent reduces adhesion to the mold, the leveling agent makes the film surface smoother and more uniform, and the defoaming agent inhibits the generation of foam, ensuring the stability and molding quality of the film, thereby improving the overall performance and transfer accuracy.

[0010] In a specific embodiment, the polyvinyl alcohol includes high molecular weight polyvinyl alcohol and low molecular weight polyvinyl alcohol, and the mass ratio of the high molecular weight polyvinyl alcohol to the low molecular weight polyvinyl alcohol is 1:(0.1-9). In a specific embodiment, the alcoholysis degree of the high molecular weight polyvinyl alcohol is 85-90%, and the polymerization degree of the high molecular weight polyvinyl alcohol is 1500-2000; the alcoholysis degree of the low molecular weight polyvinyl alcohol is 80-90%; and the polymerization degree of the low molecular weight polyvinyl alcohol is 200-500. By employing this technical solution, high-molecular-weight polyvinyl alcohol typically exhibits higher solubility and a slower dissolution rate, while low-molecular-weight polyvinyl alcohol exhibits a faster dissolution rate and shorter dissolution time. By blending high-molecular-weight and low-molecular-weight polyvinyl alcohols in a specific ratio, the solubility properties of the film can be optimized, achieving a balance among dissolution rate, mechanical properties, and surface compatibility.

[0011] In a specific embodiment, the plasticizer is an alcohol small molecule, including one or more of glycerol, propylene glycol, ethylene glycol, 1,2-hexanediol, butanediol, isophorone diol, polyethylene glycol, sorbitol, urea, diethanolamine, diglycerol succinate, diglycerol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and trimethylolpropane.

[0012] By adopting the above technical solution and using the above materials as plasticizers, the glass transition temperature of the polymer can be effectively lowered, which makes the polyvinyl alcohol film have better flexibility and ductility, avoids brittle cracking at low temperatures, and improves the operability of the film.

[0013] In a specific embodiment, the surfactant includes one or more of Tween 80, lauryl polyoxyethylene alcoholamine, polyoxyethylene alkyl ether, alkylphenol polyoxyethylene ether, polyoxyethylene alkylphenyl ether, alkyl glycoside, fatty acid methyl ester sulfonate, soybean lecithin and alkyl alcohol amide.

[0014] By adopting the above technical solution, the above surfactant has the ability to reduce the interfacial tension between liquid and solid, and between liquid and liquid, and can improve the wettability and fluidity of the solution, making the PVA solution easier to apply and spread, and improving the uniformity and quality of film formation; by adjusting the type and content of the surfactant, the flexibility, tensile strength, hygroscopicity and water solubility of the PVA film can be improved.

[0015] In a specific embodiment, the film-forming aid includes one or more of hydroxypropyl methylcellulose, EDTA ammonium salt, nano-alumina, and starch.

[0016] By adopting the above technical scheme, hydroxypropyl methylcellulose can improve the film-forming properties of the film, make the film surface smoother and more uniform, and improve the density and mechanical properties of the film; EDTA ammonium salt removes metal ions in water through chelation, reduces the hardness of water, prevents excessive cross-linking of the PVA film, and improves the uniformity and surface smoothness of the film. At the same time, EDTA ammonium salt promotes the rapid dissolution of the PVA film in water, especially in a hard water environment, can significantly shorten the dissolution time of the film, and effectively inhibit the cross-linking side reaction under high temperature or acidic conditions, thereby ensuring the complete solubility of the film; nano-alumina enhances the mechanical properties of the film and prevents the deformation of the film; starch enhances the mechanical properties of the film, plays an auxiliary role in film formation during the film-forming process, reduces the amount of PVA used, and thus reduces costs. At the same time, the hydrophilicity of starch helps to accelerate the swelling and dissolution rate of the film in water.

[0017] In a specific embodiment, the hydrophilic material includes one or more of a hydrophilic monomer, a hydrophilic polymer, a sugar compound, and an amino acid; The hydrophilic monomer is one or more of acrylic acid, methacrylic acid, ethyl acrylate, and acrylamide; the hydrophilic polymer is one or more of polyethylene glycol, polyacrylamide, chitosan, polyvinyl pyrrolidone, and polyethylene oxide; the carbohydrate compound is one or more of glucose and sucrose; and the amino acid is one or more of glycine, aspartic acid, glutamic acid, arginine, and lysine.

[0018] By adopting the above-mentioned technical solution and incorporating hydrophilic materials such as hydrophilic monomers, hydrophilic polymers, sugar compounds, amino acids, etc. into the film, not only the dissolution rate and uniformity of the film are significantly improved, but also the compatibility, mechanical properties and environmental friendliness of the film to the silicon wafer are optimized. The dissolution rate and stability of the material are optimized, making the film more stable during the transfer process, improving production efficiency, and meeting environmental protection requirements.

[0019] In a specific embodiment, the release agent is an internal release agent, which includes one or more of fatty acids and their derivatives, mineral oil derivatives, silicone oil derivatives, and inorganic fillers.

[0020] By adopting the above technical solution, the internal release agent can reduce the adhesion of the PVA solution to the patterned mold, ensuring that the film is completely peeled off without deformation; the internal release agent can reduce surface defects of the film layer, such as scratches and bubbles, through lubrication or interface isolation, thereby improving the surface quality and stability of the film.

[0021] In a specific embodiment, the leveling agent includes one or more of polyether polyurethane and modified silicone.

[0022] By adopting the above technical solution and using polyether polyurethane and modified silicones as leveling agents, the surface smoothness of the film can be significantly improved, surface defects can be reduced, the film can be ensured to be uniform and smooth during the molding process, and the overall quality and appearance of the film layer can be improved, thereby enhancing the stability and applicability of the film.

[0023] In a specific embodiment, the defoaming agent includes one or more of a silicon-based defoaming agent and a polyether defoaming agent.

[0024] By adopting the above technical solutions, the defoamer can effectively remove bubbles during the processing, improve the surface smoothness of the film, reduce pores and defects, and optimize the processing performance, ensuring stable film quality and improving overall mechanical properties.

[0025] A method for preparing a composition for transfer printing comprises the following steps: Add polyvinyl alcohol to water, stir and dissolve at 85-95°C for 0.5-1.5 hours to form a polyvinyl alcohol solution; Cool the polyvinyl alcohol solution to 60-70°C; After cooling, add plasticizer, film-forming aid, surfactant, hydrophilic material, release agent, leveling agent and defoaming agent in sequence; Continue stirring for 0.5-1 hour to obtain a composition for transfer printing; The weight percentages of the components are as follows: polyvinyl alcohol: 6-40%; plasticizer: 0.05-5%; film-forming aid: 3-20%; surfactant: 0.05-5%; hydrophilic material: 1-20%; release agent: 0.01-0.5%; leveling agent: 0.01-1%; defoaming agent: 0.01-1%; and the balance is water.

[0026] By adopting the above-mentioned technical solution, the solution optimizes the composition used for transfer, reasonably adjusts the formula, adds surfactants, hydrophilic materials, plasticizers and film-forming aids, thereby improving the flexibility and tear resistance of the film and making it have better mechanical properties; it also maintains high elasticity to avoid breakage or deformation during use, effectively improving the dissolution rate, mechanical properties, environmental protection and compatibility of the film with silicon wafers or conductive pastes; by optimizing the ingredient ratio and process flow, the dissolution rate, mechanical properties, environmental protection and compatibility of the composition used for transfer with silicon wafers or conductive pastes are improved.

[0027] A method for preparing an electrode grid line, comprising: using the transfer composition according to any one of claims 1 to 10 to prepare a polymer layer having a groove pattern, wherein the size and distribution of the groove pattern correspond to the size and distribution of the electrode grid line; filling the groove pattern of the polymer layer with a conductive paste; Providing a silicon wafer, with the side coated with the conductive paste facing the silicon wafer, and covering the polymer layer on the silicon wafer; Performing hot pressing transfer to transfer the conductive paste onto the silicon wafer; The polymer layer is dissolved and removed by using an aqueous solution to obtain the electrode grid lines.

[0028] In a specific embodiment, making a polymer layer having a groove pattern includes: providing a substrate and a mold, the mold having protrusions corresponding to the electrode grid line pattern, coating the composition on the substrate, using the mold to imprint a groove pattern on the composition, drying and shaping the composition, and obtaining a polymer layer having a groove pattern.

[0029] By adopting the above-mentioned technical solution, the composition for transfer of the present application serves as a transfer carrier, which can not only withstand high temperature and high pressure and accurately transfer the electrode grid line pattern, but also can be quickly solidified, thereby accelerating the preparation speed of the electrode grid line and improving production efficiency; and the composition for transfer can be removed by a simple water dissolution treatment after the transfer is completed; the application of the composition for transfer of the present application in the preparation of electrode grid lines not only improves the transfer accuracy and efficiency, but also has the advantages of environmental protection, economy, and high efficiency, which can improve the quality and performance of the final product.

[0030] To sum up, the beneficial technical effects of the present application are as follows: the present application improves the dissolution rate of the film in water by reasonably adjusting the molecular weight and ratio of polyvinyl alcohol; through formulation and process innovation, surfactants, hydrophilic materials, plasticizers and film-forming aids are added to improve the flexibility, tear resistance and water solubility of the film, so that it has better mechanical properties, solves the shortcomings of traditional PVA film in dissolution rate, and successfully achieves rapid water solubility, good mechanical properties and environmental protection of the film; this technology is particularly suitable for the conductive slurry process of photovoltaic cells, providing technical support for green production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic flow chart of the preparation method of the composition used for transfer printing in the present application.

[0032] Figure 2 This is a flow chart of the electrode grid line preparation method in this application. DETAILED DESCRIPTION

[0033] The present application discloses a composition for transfer printing. The composition for transfer printing includes, but is not limited to, applications in the preparation of electrode grid lines. It is also widely applicable to other high-precision transfer technologies, especially the production process of photovoltaic cells. The composition for transfer printing of the present application, as a transfer carrier for electrode grid lines, can accurately transfer the electrode grid line pattern and quickly remove the film through a simple water dissolution process. No harmful substances will remain after removal, ensuring compliance with environmental protection requirements. The composition for transfer printing comprises the following components in percentage by mass: Polyvinyl alcohol (PVA): 6-40%; as the film's base material, PVA exhibits excellent water solubility, chemical stability, and mechanical strength. By optimizing the ratio of PVAs of varying molecular weights, the film's dissolution rate and mechanical properties can be effectively adjusted. PVA primarily enhances the film's solubility, stability, and strength. Furthermore, PVA is less likely to react adversely with silicon wafers or conductive pastes, thereby preventing any impact on the photovoltaic cell's conductivity and the properties of the silicon wafer's surface. Plasticizer: 0.05-5%; the addition of plasticizer is mainly used to improve the flexibility and ductility of the film, reduce the brittleness of the film, enhance the operability of the film, and improve the crack resistance of the film, making it less likely to deform or crack during the transfer process, thereby ensuring the accuracy and integrity of the grid line pattern; Film-forming aid: 3-20%; the addition of film-forming aid can optimize the film-forming process, improve the surface smoothness and uniformity of the film, and ensure the overall quality of the film. By properly selecting the film-forming aid, the strength of the film can be improved, ensuring that the film maintains good physical properties and chemical stability during long-term use; Surfactant: 0.05-5%; the addition of surfactant can improve the wettability and fluidity of the film, making the solution more uniform during coating; surfactant can reduce the interfacial tension between liquid and solid, improve the adaptability and fluidity of the solution, thereby ensuring that the film dissolves more evenly and quickly in water; Hydrophilic materials: 1-20%; hydrophilic materials can increase the dissolution rate of the film, ensuring that the film can dissolve evenly and quickly in water, and play a positive role in the surface hydrophilicity and stability of the film, further improving the water solubility of the film and the stability during the transfer process; Release agent: 0.01-0.5%; the addition of release agent can reduce the adhesion of the film to the mold or equipment surface, facilitate demoulding, ensure the film is completely peeled off without deformation, and reduce surface defects through lubrication or interface isolation; Leveling agent: 0.01-1%; the addition of leveling agent can improve the surface smoothness of the film, reduce defects, and optimize processing performance; Defoamer: 0.01-1%; the addition of defoamer can remove bubbles during processing, improve the surface smoothness of the film, reduce pores and defects, ensure stable film quality and improve overall mechanical properties; The balance is water; water is the solvent of the film, which is used to dissolve polyvinyl alcohol and other ingredients to ultimately form a film solution.

[0034] In this embodiment, polyvinyl alcohol includes high molecular weight polyvinyl alcohol and low molecular weight polyvinyl alcohol, and the mass ratio of high molecular weight polyvinyl alcohol to low molecular weight polyvinyl alcohol is 1:(0.1-9). In this embodiment, polyvinyl alcohol includes one or more mixtures of PVA3088, PVA2488, PVA2088, PVA1788, PVA1780, and PVA0588. By reasonably selecting the ratio and characteristics of high molecular weight and low molecular weight polyvinyl alcohol, the production efficiency and film forming effect can be improved while ensuring the solubility, mechanical properties, environmental protection and compatibility of the film with other materials (such as silicon wafers, conductive pastes, etc.).

[0035] In this embodiment, the main function of the high molecular weight polyvinyl alcohol in the film is to improve the balance between the structural strength and dissolution rate of the film, and to provide good adhesion and stability. In this embodiment, the high molecular weight polyvinyl alcohol used has the following characteristics: The degree of alcoholysis is 85-90%: This degree of alcoholysis means that the vinyl ether group in the polyvinyl alcohol molecule has a high degree of hydrolysis, which helps to improve the water solubility and dissolution rate of polyvinyl alcohol, thereby improving the film removal efficiency, reducing residues in the production process, and meeting environmental protection requirements.

[0036] The degree of polymerization is 1500-2000: A higher degree of polymerization means that the chain length of the polyvinyl alcohol molecules is longer, which increases the mechanical strength and durability of the film, but has a lower dissolution rate compared to polyvinyl alcohol with a low degree of polymerization; therefore, in the design, the balance between the solubility characteristics and mechanical properties of the film is optimized by controlling the ratio of high molecular weight polyvinyl alcohol to low molecular weight polyvinyl alcohol.

[0037] In this embodiment, low molecular weight polyvinyl alcohol improves the water solubility of the film mainly by increasing the dissolution rate of the film, further enhancing the adaptability and processing performance of the film. In this embodiment, the main characteristics of low molecular weight polyvinyl alcohol are as follows: The alcoholysis degree is 80-90%: The alcoholysis degree of low molecular weight polyvinyl alcohol is slightly lower than that of high molecular weight polyvinyl alcohol, which makes it have a better dissolution rate; it has fewer hydrolyzed groups, which can improve the mechanical flexibility and crack resistance of the film.

[0038] The degree of polymerization is 200-500: Low molecular weight polyvinyl alcohol has a lower degree of polymerization, which means that its molecular chain is shorter and the dissolution rate is faster, which can better meet the demand for rapid dissolution of the film in a short time. This is especially important when rapid film removal is required during production, while ensuring that after the film is dissolved, it will not affect the downstream process.

[0039] In this embodiment, different performances are achieved by adjusting PVA-related parameters, specifically including: Reduce the degree of alcoholysis: The lower the degree of alcoholysis, the higher the content of unhydrolyzed acetate groups in the PVA molecules. This will reduce the regularity of the molecular chain, thereby weakening the intermolecular force, making it easier for water molecules to penetrate between the molecular chains and speeding up the dissolution rate. For example, the degree of alcoholysis can be reduced from 88-90% to 85-87%. However, too low an alcoholysis degree may affect the mechanical properties of the film, so it should be adjusted appropriately.

[0040] Reduce the degree of polymerization: A low degree of polymerization means that the PVA molecular chain is shorter, the degree of intermolecular entanglement is reduced, and the intermolecular force is weakened, which is conducive to the diffusion and penetration of water molecules. For example, the degree of polymerization can be reduced from 1700-2000 to 1500-1700; however, too low a degree of polymerization will reduce the strength of the film, and the relationship between water dissolution time and mechanical properties needs to be weighed.

[0041] Finally, high molecular weight PVA with a degree of polymerization of 1700 and a degree of alcoholysis of 88% and low molecular weight PVA with a degree of polymerization of 500 and a degree of alcoholysis of 88% were selected. PVA1788 and PVA0588 were mixed in a certain ratio of 1: (0.1-9) to obtain comprehensive performance.

[0042] In this embodiment, the plasticizer includes small molecules of alcohols, including one or more of glycerol (glycerine), propylene glycol, ethylene glycol, 1,2-hexanediol, butanediol, isophorone diol, polyethylene glycol, sorbitol, urea, diethanolamine, diglyceryl succinate, diglycerol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and trimethylolpropane: preferably, the plasticizer of the present application is glycerine (glycerine), and in this embodiment, the added amount of glycerine is preferably 0.05-0.2%; Glycerol is a common plasticizer with excellent hydrophilicity and solubility. The molecular structure of glycerol contains multiple hydrogen bond formation points, which can form hydrogen bonds with the molecular chains of polyvinyl alcohol, which helps to improve the flexibility and ductility of the film. The hydrophilic properties of glycerol can promote the water solubility of polyvinyl alcohol films and reduce the time required for them to dissolve, which is particularly important in the application of water-soluble films.

[0043] In this embodiment, the plasticizer also includes polyvinyl pyrrolidone. Polyvinyl pyrrolidone (PVP) also acts as a plasticizer in the preparation of PVA polymer film. Its function is to form hydrogen bonds with PVA molecules through pyrrolidone groups, provide steric hindrance effects, prevent aggregation of molecular chains in the film, and enhance the uniformity and water solubility rate of the film. In addition, polyvinyl pyrrolidone does not contain sodium and has high biocompatibility, and is suitable for silicon wafer transfer films that are sensitive to ion residues in the photovoltaic field.

[0044] In this embodiment, the film-forming aid includes one or more of hydroxypropyl methylcellulose, EDTA ammonium salt, nano-alumina, and starch. In this embodiment, the film-forming aid includes, by weight percentage, hydroxypropyl methylcellulose: 0.1-8%; EDTA ammonium salt: 0.1-2%; nano-alumina: 0.1-3%; starch: 2-15%. The selection and proportion of the film-forming aid are crucial for the preparation of high-performance films. The film-forming aid can not only improve the performance of the film, but also adjust the operability, mechanical properties, moisture resistance, and environmental friendliness of the film. The following are the specific characteristics and functions of several film-forming aids: Hydroxypropyl methylcellulose (HPMC): 0.05-5%; HPMC, as a water-soluble cellulose derivative, has a strong thickening effect, can increase the viscosity of the solution and enhance the rheological properties of the film-forming liquid; it can form a uniform film with a smooth surface and good mechanical strength and aging resistance; HPMC has strong hydrophilicity, which can promote the uniform dispersion of the film-forming solution and help improve the stability and mechanical properties of the film; In this embodiment, the amount of HPMC can be adjusted according to the thickness of the film and the required mechanical properties. The amount of hydroxypropyl methylcellulose (HPMC) can be appropriately reduced, reducing its mass percentage from 2-5% to 0.05-2%. Although HPMC helps to form the film and improve the mechanical properties of the film, excessive HPMC will hinder the penetration of water molecules to a certain extent. Reducing its amount can accelerate the dissolution rate.

[0045] EDTA ammonium salt: 0.1-2%; EDTA ammonium salt removes metal ions from water through chelation, reduces water hardness, prevents excessive cross-linking of the PVA film, and improves the uniformity and surface smoothness of the film. At the same time, EDTA ammonium salt promotes the rapid dissolution of the PVA film in water, especially in hard water environments, significantly shortening the film's dissolution time. It also effectively inhibits cross-linking side reactions under high temperature or acidic conditions, thereby ensuring the complete solubility of the film. In this embodiment, the amount of EDTA ammonium salt can be adjusted according to the actual needs of the membrane; if the stability and water resistance of the film need to be enhanced, its amount can be increased to 2%; if the antibacterial properties of the membrane are of concern, 0.5-1.5% is recommended as the appropriate ratio.

[0046] Nano-alumina: 0.1-3%; Nano-alumina has an extremely high specific surface area and can form a uniformly dispersed network in the film, thereby improving the film's strength, hardness, and tensile strength. Its nano-scale particles can effectively prevent the formation of microcracks in the film, improving its durability. Nano-alumina also has good thermal stability and can improve the film's high-temperature resistance, making it suitable for use in high-temperature environments. In addition, nano-alumina can also provide a certain degree of UV resistance, delaying the film's aging process. Nano-zinc oxide: 0.1-3%; can enhance the mechanical properties and heat resistance of PVA film and increase its oxygen permeability. Adding nano-zinc oxide to PVA film can improve its gas permeability, especially water vapor permeability, mainly by loosening the structure, making the film pores larger, making it easier for water to penetrate, thereby accelerating the dissolution process. At the same time, the improvement in oxygen permeability is related to the structural density of the film. A more open structure facilitates water penetration and shortens the water dissolution time. Starch: 2-15%; starch includes one or more of mung bean starch, tapioca starch, sweet potato starch, potato starch, wheat starch, water chestnut starch, lotus root starch, and corn starch. Starch can interact with film-forming substances such as PVA to assist in the film-forming process, making the film structure more uniform and dense, thereby improving the film's film quality. This effect enhances the film's mechanical strength and flexibility, reducing the risk of cracking or embrittlement during preparation and use. Starch molecules contain a large number of hydroxyl groups and have good hydrophilicity. Their molecular structure can form hydrogen bonds with water molecules, thereby improving the overall hydrophilicity of the film. As a natural polymer material, starch is not only widely available but also biodegradable. Adding starch to the film formula can significantly improve the film's environmental friendliness and reduce pollution to the environment.

[0047] In this embodiment, an appropriate starch ratio can be selected according to the final use of the film. Factors to consider when using starch: Film performance requirements: Emphasis on water solubility: If you want the film to completely dissolve in a shorter time, the amount of starch added can be appropriately increased to 10-15%; this will accelerate the swelling and dissolution rate of the film in water and enhance the water solubility of the film.

[0048] Focus on mechanical properties: If the film has high requirements for mechanical properties such as tensile strength and flexibility, the amount of starch added should be controlled between 5-10%; too much starch may affect the molecular interaction between film-forming substances such as PVA, thereby causing a decrease in the mechanical properties of the film.

[0049] Other ingredient ratios: PVA content: PVA, as the primary film-forming substance, has a synergistic effect with starch. If the PVA content is high, the starch dosage can be appropriately increased (10-15%) to facilitate the interaction between the two and improve the overall performance of the film. If the PVA content is low, the starch addition should be controlled at 5-10% to avoid affecting the film's film-forming effect.

[0050] Plasticizers and other additives: Plasticizers (such as glycerol) can improve the compatibility of starch and PVA and ensure good dispersion of starch in the system. It is recommended to control the amount of starch added to 2-5%; The role of starch in film formulation is not only reflected in improving hydrophilicity, improving film-forming properties, increasing environmental protection and reducing costs, but also in optimizing film performance by reasonably controlling the dosage. In the film formulation design, the amount of starch added needs to be adjusted according to specific performance requirements, PVA content and the ratio of other ingredients to achieve the best balance of performance.

[0051] In this embodiment, the surfactant includes one or more of Tween 80, lauryl polyoxyethylene alcohol amine, polyoxyethylene alkyl ether, alkylphenol polyoxyethylene ether, polyoxyethylene alkylphenyl ether and alkyl alcohol amide; In this embodiment, Tween 80 is preferred and its addition amount is 0.05-2%. Tween 80 is a non-ionic surfactant with excellent emulsifying, dispersing and solubilizing properties. In the process of promoting film dissolution, Tween 80 can effectively reduce surface tension and increase the affinity between water and the film, thereby improving the solubility of the film. Compared with the conventional surfactant sodium dodecylbenzenesulfonate, Tween 80 produces less foam, which is very important for controlling excessive foam formation during the coating process, especially for coating and penetration applications requiring film uniformity.

[0052] In addition to the selection and ratio of surfactants, the formulation can be further optimized by: Adjusting the pH of the solution: The pH value of the solution will affect the activity of the surfactant. Proper adjustment of the pH of the solution (for example, maintaining it in a neutral or slightly acidic range) can further enhance the effect of the surfactant.

[0053] Optimize solution temperature: Increasing the temperature of the solution can help accelerate the dissolution process, but it should be noted that too high a temperature may cause degradation or instability of the ingredients, so it is recommended to optimize the operation within the temperature range.

[0054] Adding stabilizers: If the surfactant combination used affects the stability of the solution, an appropriate amount of stabilizer (such as a polymer stabilizer) can be added to avoid stratification of the emulsion or solution during long-term storage.

[0055] In this embodiment, the hydrophilic material includes one or more of a hydrophilic monomer, a hydrophilic polymer, a carbohydrate compound, and an amino acid; The hydrophilic monomer is one or more of acrylic acid, methacrylic acid, ethyl acrylate, and acrylamide. The hydrophilic monomer not only enhances the hydrophilicity of the film but also forms a polymer with specific functions through polymerization, thereby improving the stability and performance of the film. In this embodiment, the hydrophilic monomer is preferably acrylic acid, which is widely used in the preparation of water-soluble films and has good hydrophilicity and reactivity. It can undergo copolymerization with other monomers, thereby improving the stability and strength of the film. Hydrophilic monomers such as acrylic acid are introduced, and their content is controlled at 1-3%; these monomers can interact with PVA to a certain extent, further increasing the hydrophilic sites on the surface and inside of the film, and promoting the adsorption and penetration of water molecules.

[0056] The hydrophilic polymer is one or more of polyethylene glycol, polyacrylamide, chitosan, polyvinyl pyrrolidone, and polyethylene oxide; Polyethylene glycol (PEG) has good solubility and low molecular weight deformability. It can form hydrogen bonds with water molecules, increase the hydrophilicity of the film, promote dissolution, and improve the flexibility of the film, making it easier to process. Polyacrylamide (PAM) can quickly absorb water and swell, increasing the hydration of the film and improving the viscosity and stability of the film, especially in high humidity environments; Chitosan is antibacterial and biodegradable, and can complement other ingredients to enhance the stability, antibacterial properties and environmental friendliness of the film; In this embodiment, the amount of polymer added is generally between 1-10%, and the specific amount can be adjusted according to the required dissolution rate, mechanical properties and film flexibility.

[0057] The sugar compound is one or more of glucose and sucrose; Glucose molecules contain multiple hydroxyl groups and have good hydrophilicity. They can form hydrogen bonds with water molecules, increase the adsorption and penetration of water molecules on the film surface, and promote the dissolution of the film. At the same time, glucose is a natural organic compound that is environmentally friendly and meets environmental protection requirements. It is recommended to add 1-6% glucose. Adding too much glucose may make the film surface sticky and affect the use of the film.

[0058] Sucrose molecules also have multiple hydroxyl groups and are highly hydrophilic. They can dissolve in water and form solutions, reducing the surface tension of water, making it easier for water molecules to enter the film and accelerating the dissolution process of the film. The addition amount is controlled between 1-6%. Too much sucrose may crystallize during the film drying process, affecting the quality of the film.

[0059] The amino acid is one or more of glycine, aspartic acid, glutamic acid, arginine, and lysine; in this embodiment, the amino acid is preferably glycine as the hydrophilic material. The glycine molecule contains amino and carboxyl groups, has good hydrophilicity and amphoteric properties, can interact with water molecules and film molecules, and increase the hydrophilicity and solubility of the film; at the same time, it also has a certain buffering effect, can adjust the pH of the solution, and improve the stability of the film; the addition amount is 1-4%, and an appropriate amount of glycine can effectively improve the water solubility of the film without affecting its other properties.

[0060] In this embodiment, the release agent is an internal release agent. The main function of the internal release agent is to reduce the adhesion of the film to the mold or equipment surface and facilitate demolding. Its components are compatible with PVA and do not affect water solubility. In this embodiment, in the subsequent process of preparing electrode grid lines, after the composition used for transfer is used to prepare the film (that is, the polymer layer in the subsequent part), an external release agent (such as a silane release agent, a fluorine-containing release agent, a wax-based release agent, etc.) can be sprayed on the surface of the polymer layer with grooves as needed, thereby improving the surface quality and stability of the film.

[0061] Internal mold release agents include one or more of fatty acids and their derivatives, mineral oil derivatives, silicone oil derivatives, and inorganic fillers.

[0062] Fatty acids and their derivatives include calcium stearate, stearic acid, glyceryl monostearate, zinc stearate, etc.; fatty acids and their derivatives form a micro-lubricating layer on the surface of the film, reducing friction with the mold and improving the demolding effect.

[0063] Mineral oil and silicone oil derivatives include emulsified silicone oil, polyether-modified silicone oil, modified polydimethylsiloxane (PDMS), etc. Polyether-modified silicone oil is compatible with PVA through its polyether segment, and can migrate to the surface when the processing temperature rises, forming a low surface tension isolation layer, effectively improving the demolding effect.

[0064] Inorganic fillers include nano-silica, talc, calcium carbonate, etc.; they reduce the contact area between the film and the mold through physical isolation and improve demolding properties; it should be noted that excessive inorganic fillers may increase the haze of the film and affect the appearance.

[0065] In this embodiment, the leveling agent includes polyether polyurethane, modified silicone, etc. Polyether polyurethanes include CSP-200LP and CSP-020LP (containing 25% active ingredients). Polyether polyurethanes adjust melt viscosity, balance fluidity under high and low shear rates, reduce surface tension differences, and mitigate defects caused by uneven surface tension, such as orange peel and shrinkage craters. Modified silicones include polyether-modified silicone oils, acrylate-modified silicones, etc.; modified silicones can reduce the surface energy of the film, enhance wettability, reduce bubble generation and uneven interfacial tension, while increasing the smoothness of the film and improving the overall appearance and quality of the film.

[0066] In this embodiment, the defoaming agent includes a silicon-based defoaming agent, an organic defoaming agent, a polyether defoaming agent, etc. Silicone-based defoamers are environmentally friendly. Based on organosilicon compounds, they can be easily decomposed in the environment and will not pollute water or soil for a long time. They are highly effective in eliminating bubbles and reducing surface defects, making them very suitable for use in film production that requires high surface quality. Polyether defoamer has good biodegradability and does not contain harmful substances. It can effectively eliminate bubbles and has little interference with other ingredients during processing, which can ensure the stability of the film surface quality.

[0067] Reference Figure 1 This embodiment provides a method for preparing a composition for transfer printing. In this embodiment, the components and their proportions in the method for preparing the composition for transfer printing are described above. The method comprises the following steps: Add polyvinyl alcohol to water and stir and dissolve it at a temperature of 85-95°C for 0.5-1.5 hours. In this embodiment, preferably, stir and dissolve it at a temperature of 90°C for 1 hour to form a polyvinyl alcohol solution. This step must ensure that the polyvinyl alcohol is completely dissolved to avoid the occurrence of insoluble particles or agglomerations, thereby ensuring the uniformity and stability of the subsequent mixed solution.

[0068] Cooling the polyvinyl alcohol solution to 60-70° C. In this embodiment, preferably, cooling the polyvinyl alcohol solution to 65° C.; After cooling, a plasticizer, a film-forming aid, a surfactant, a hydrophilic material, a release agent, a leveling agent, and a defoaming agent are added in sequence, and stirring is continued for 0.5-1 hour. In this embodiment, stirring is preferably continued for 0.5 hour to obtain a composition for transfer printing; The weight percentages of the components are as follows: polyvinyl alcohol: 6-40%; plasticizer: 0.05-5%; film-forming aid: 3-20%; surfactant: 0.05-5%; hydrophilic material: 1-20%; release agent: 0.01-0.5%; leveling agent: 0.01-1%; defoaming agent: 0.01-1%; and the balance is water.

[0069] This solution optimizes the composition used for transfer, rationally adjusts the formula, and adds surfactants, hydrophilic materials, plasticizers, and film-forming aids to improve the flexibility and tear resistance of the film, giving it better mechanical properties. It also maintains high elasticity to avoid breakage or deformation during use, effectively improving the film's dissolution rate, mechanical properties, environmental friendliness, and compatibility with silicon wafers or conductive pastes. By optimizing the ingredient ratio and process flow, the dissolution rate, mechanical properties, environmental friendliness, and compatibility with silicon wafers or conductive pastes of the composition used for transfer are improved.

[0070] Reference Figure 2 This embodiment also provides a method for preparing an electrode grid line, using the above-mentioned transfer composition as a transfer carrier; In this embodiment, the method for preparing the electrode grid line includes the following steps: 1. Providing a substrate and a mold, wherein the mold has protrusions corresponding to the electrode grid line pattern, and using the above-mentioned composition for transfer, making a polymer layer with a groove pattern, wherein the size and distribution of the groove pattern correspond to the size and distribution of the electrode grid lines; The method of preparing the polymer layer having the groove pattern specifically includes: coating a composition on a substrate, imprinting a groove pattern on the composition using a mold, and drying and shaping the composition to obtain a polymer layer having the groove pattern; 2. Filling the groove pattern of the polymer layer with conductive paste; 3. Providing a silicon wafer, with the side coated with the conductive paste facing the silicon wafer, and covering the polymer layer on the silicon wafer; 4. Perform hot pressing transfer to transfer the conductive paste onto the silicon wafer; 5. The polymer layer is dissolved and removed by aqueous solution to complete the production of electrode grid lines.

[0071] By optimizing each step, this preparation method not only improves the overall performance of the transfer composition, but also ensures the controllability and efficiency of the film in different applications. By optimizing the dissolution equipment, ingredients, casting process, drying process, etc., the production efficiency and film quality are improved, ensuring that the film meets the expected requirements in terms of mechanical properties, dissolution rate, surface properties, etc. The customized film properties enable this method to be widely used in electronics, environmental protection, packaging, medical and other fields, meeting the special requirements of different application environments for films. Specific embodiments Some specific implementation methods will be further introduced below to further explain the technical solution of this application in detail.

[0073] Example 1 Preparation method: PVA1788 and PVA0588 were added to water and stirred and dissolved at 90°C for 1 hour to form a polyvinyl alcohol solution; After the polyvinyl alcohol solution is cooled to 65°C, glycerol, sorbitol, hydroxypropyl methylcellulose, EDTA ammonium salt, nano-alumina, starch, Tween 80, acrylic acid, chitosan, polyvinyl pyrrolidone, glucose, glycine, calcium stearate, polyether-modified silicone oil, and a silicone-based defoaming agent are added in sequence, and stirring is continued for 0.5 hours to obtain a composition for transfer printing; A polymer layer with grooves is prepared using a composition for transfer printing; specifically, a substrate is provided, the composition is coated on the substrate, a groove pattern is embossed on the composition using a mold, and the composition is dried and shaped to obtain a polymer layer with a groove pattern.

[0074] Example 2 The difference from Example 1 is that the mass percentage of PVA 1788 is changed from 9% to 15%; the components are the same as those in Example 1, and the remaining method steps are the same as those in Example 1.

[0075] Example 3 The difference from Example 1 is that the mass percentages of PVA 1788 and PVA0588 are 7.5% and 7.5% respectively; the components are the same as those in Example 1, and the remaining method steps are the same as those in Example 1.

[0076] Example 4 The difference from Example 1 is that the glycerol is 0.1% and the sorbitol is 0.2%; the components are the same as those in Example 1, and the remaining method steps are the same as those in Example 1.

[0077] Example 5 The difference from Example 1 is that the starch content is 0.6%; the components are the same as those in Example 1, and the remaining method steps are the same as those in Example 1.

[0078] Comparative Example 1 Preparation method: Add 15% PVA1788 to water and stir and dissolve at 90°C for 1 hour to form a polyvinyl alcohol solution; After the polyvinyl alcohol solution was cooled to 65°C, glycerol was added and stirred for 0.5 hours to obtain a mixed solution; The mixed solution was poured into a mold with a pattern and cast to form a film at a casting speed of 8 cm / min. The mold with the film was placed in a drying oven and dried at 85°C for 5 minutes to obtain a traditional PVA film.

[0079] Related test descriptions: 1. Dissolution performance test: Place the prepared membrane sample (30 micron thick) in deionized water at 25°C. Start timing and record the time it takes for the membrane sample to completely dissolve from the moment it contacts the water surface. This test evaluates the dissolution efficiency of the membrane material and verifies the dissolution rate.

[0080] 2. Mechanical properties testing: The membrane samples are tested for tensile strength and elongation at break using a universal material testing machine. During the test, the membrane sample is clamped in the testing machine's fixture and stretched at a constant speed until the membrane breaks. By recording the maximum force during stretching and the elongation at break, the tensile strength and elongation of the membrane sample can be calculated. This assesses the mechanical stability of the membrane material and ensures its shape retention during subsequent processing.

[0081] 3. Silver paste transfer accuracy test. During the silver paste transfer test, silver paste is first filled into the grooves of the film sample. The film sample with silver paste is then transferred to the silicon wafer surface. Subsequently, the film layer is dissolved to release the silver paste, and then cured and sintered at an appropriate temperature to ensure a close bond between the silver paste and the silicon wafer. Finally, the width and resistivity of the gate lines are measured using precision measurement tools to evaluate the transfer accuracy and the quality of the silver paste-silicon bond.

[0082] Please refer to the table below for specific test results. Analysis of technical effects and implementation methods 1. Rapid water-soluble performance The dissolution time of this application at room temperature (20-25°C) can be controlled within 75 seconds, meeting the demand for rapid removal of thin films during photovoltaic cell production and significantly improving production efficiency.

[0083] Implementation: Control of alcoholysis degree and polymerization degree: Select the appropriate type of polyvinyl alcohol (PVA) to make it have good water solubility and ensure rapid dissolution in water.

[0084] Application of surfactant: Tween 80 is added as a surfactant to reduce the surface tension of water, promote the penetration of water molecules into the film structure, and accelerate the dissolution of the film.

[0085] Introduction of hydrophilic materials: Use hydrophilic monomers, hydrophilic polymers, sugar compounds, amino acids, etc. to further enhance the hydrophilicity and water absorption and swelling properties of the film, ensuring rapid dissolution of the film.

[0086] 2. Environmental protection and green formula The formula of this application is completely free of harmful substances, all ingredients have good biocompatibility and degradability, and meet green environmental protection standards; it will not cause any harm to the environment or human health during production and use.

[0087] 3. Compatibility with silicon wafers and conductive pastes The present application does not undergo chemical reactions when in contact with silicon wafers and conductive pastes, thereby ensuring the surface performance of the silicon wafers and the stability of the conductive pastes, thereby improving the photoelectric conversion efficiency and overall stability of the photovoltaic cells.

[0088] Implementation: Each component in the formula is rigorously screened to ensure that the materials used are chemically stable and do not react with silicon wafers or conductive pastes. At the same time, by optimizing the film preparation process, its surface properties and chemical composition are precisely controlled to improve the compatibility between the film and silicon wafers and conductive pastes.

[0089] 4. Mechanical properties and stability The present application has sufficient mechanical strength and flexibility to maintain the integrity of the pattern during the transfer process, avoid deformation or rupture of the film, and ensure the quality of the electrode grid line transfer.

[0090] Implementation: Addition of plasticizers: By adding plasticizers such as glycerin to the film formula, the flexibility and plasticity of the film can be improved, and its shape stability during the transfer process can be enhanced.

[0091] Application of film-forming aids: Using HPMC and other materials as film-forming aids not only improves the film-forming properties of the film, but also improves the density and mechanical strength of the film.

[0092] Process parameter optimization: Adjust the casting speed and drying temperature to ensure that the physical properties of the film are optimal and that the film maintains a stable shape during the transfer process.

[0093] The composition for transfer printing of the present application can solve the shortcomings of traditional PVA film in dissolution rate and high-temperature decomposition efficiency through formulation and process innovation, and successfully achieve rapid water solubility, good mechanical properties and environmental protection of the film; this technology is particularly suitable for the conductive paste process of photovoltaic cells, providing technical support for green production; at the same time, the environmental protection of the film and its compatibility with photovoltaic production processes significantly improve the manufacturing quality and production efficiency of photovoltaic cells, laying a solid foundation for future industrial applications.

[0094] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A composition for transfer printing, characterized in that: The invention comprises the following components in weight percentage: polyvinyl alcohol: 6-40%; Plasticizer: 0.05-5%; Film-forming aid: 3-20%; surfactant: 0.05-5%; hydrophilic material: 1-20%; Release agent: 0.01-0.5%; Leveling agent: 0.01-1%; Defoaming agent: 0.01-1%; the balance is water.

2. The composition for transfer according to claim 1, characterized in that: The polyvinyl alcohol includes high molecular weight polyvinyl alcohol and low molecular weight polyvinyl alcohol, and the mass ratio of the high molecular weight polyvinyl alcohol to the low molecular weight polyvinyl alcohol is 1:(0.1-9).

3. The composition for transfer according to claim 2, characterized in that: The alcoholysis degree of the high molecular weight polyvinyl alcohol is 85-90%, and the polymerization degree of the high molecular weight polyvinyl alcohol is 1500-2000; the alcoholysis degree of the low molecular weight polyvinyl alcohol is 80-90%; and the polymerization degree of the low molecular weight polyvinyl alcohol is 200-500.

4. The composition for transfer according to claim 1, characterized in that: The plasticizer is an alcohol small molecule, including one or more of glycerol, propylene glycol, ethylene glycol, 1,2-hexanediol, butanediol, isophorone diol, polyethylene glycol, sorbitol, urea, diethanolamine, diglycerol succinate, diglycerol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and trimethylolpropane.

5. The composition for transfer according to claim 1, characterized in that: The surfactant includes one or more of Tween 80, lauryl polyoxyethylene alcoholamine, polyoxyethylene alkyl ether, alkylphenol polyoxyethylene ether, polyoxyethylene alkylphenyl ether, alkyl glycoside, fatty acid methyl ester sulfonate, soybean lecithin and alkyl alcohol amide.

6. The composition for transfer printing according to claim 1, wherein: The film-forming aid includes one or more of hydroxypropyl methylcellulose, EDTA ammonium salt, nano-aluminum oxide, nano-zinc oxide, and starch.

7. The composition for transfer printing according to claim 1, wherein: The hydrophilic material includes one or more of a hydrophilic monomer, a hydrophilic polymer, a sugar compound, and an amino acid; The hydrophilic monomer is one or more of acrylic acid, methacrylic acid, ethyl acrylate, and acrylamide; the hydrophilic polymer is one or more of polyethylene glycol, polyacrylamide, chitosan, polyvinyl pyrrolidone, and polyethylene oxide; the carbohydrate compound is one or more of glucose and sucrose; and the amino acid is one or more of glycine, aspartic acid, glutamic acid, arginine, and lysine.

8. The composition for transfer printing according to claim 1, wherein: The release agent is an internal release agent, and the internal release agent includes one or more of fatty acids and their derivatives, mineral oil derivatives, silicone oil derivatives, and inorganic fillers.

9. The composition for transfer printing according to claim 1, wherein: The leveling agent includes one or more of polyether polyurethane and modified silicone.

10. The composition for transfer printing according to claim 1, characterized in that: The defoaming agent includes one or more of a silicon-based defoaming agent, an organic defoaming agent, and a polyether defoaming agent.

11. A method for preparing the composition for transfer according to any one of claims 1 to 10, characterized in that: include: Add polyvinyl alcohol to water, stir and dissolve at 85-95°C for 0.5-1.5 hours to form a polyvinyl alcohol solution; Cool the polyvinyl alcohol solution to 60-70°C; After cooling, a plasticizer, a film-forming aid, a surfactant, a hydrophilic material, a release agent, a leveling agent, and a defoaming agent are added in sequence, and stirring is continued for 0.5-1 hour to obtain a composition for transfer printing; The weight percentages of the components are as follows: polyvinyl alcohol: 6-40%; plasticizer: 0.05-5%; film-forming aid: 3-20%; surfactant: 0.05-5%; hydrophilic material: 1-20%; release agent: 0.01-0.5%; leveling agent: 0.01-1%; defoaming agent: 0.01-1%; and the balance is water.

12. A method for preparing an electrode grid line, characterized in that: include: Using the transfer composition according to any one of claims 1 to 10, a polymer layer having a groove pattern is prepared, wherein the size and distribution of the groove pattern correspond to the size and distribution of the electrode grid lines; filling the groove pattern of the polymer layer with a conductive paste; Providing a silicon wafer, with the side coated with the conductive paste facing the silicon wafer, and covering the polymer layer on the silicon wafer; Performing hot pressing transfer to transfer the conductive paste onto the silicon wafer; The polymer layer is dissolved and removed by using an aqueous solution to obtain the electrode grid lines.

13. The method for preparing an electrode grid line according to claim 12, wherein: The preparation of a polymer layer having a groove pattern includes: providing a substrate and a mold, wherein the mold has protrusions corresponding to the electrode grid line pattern, coating the composition on the substrate, using the mold to emboss the groove pattern on the composition, and drying and shaping the composition to obtain a polymer layer having a groove pattern.

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