Preparation method for electrode grid lines, and photovoltaic cell

Abstract

The present application relates to the field of photovoltaic technology, and particularly relates to a preparation method for electrode grid lines, and a photovoltaic cell. The method comprises the following steps: S1, providing a substrate, and forming a polymer layer on the substrate; S2, providing a mold in correspondence to a desired electrode pattern, and using the mold to press the polymer layer so as to form grooves in correspondence to the electrode pattern; S3, coating the polymer layer with a conductive material until the grooves are filled with the conductive material, and scraping off excess conductive material; S4, drying the conductive material; S5, dissolving the polymer layer after the drying; and S6, sintering the conductive material to form electrode grid lines. The method can achieve the formation of electrode patterns having high printing precision, almost without the generation of waste materials, thereby greatly reducing the consumption of materials and the costs. Moreover, the method has simple process flow, high process precision and high production efficiency, can align with the concept of green sustainable development, and helps to promote the application of environmentally friendly production processes.

Description

Electrode grid line preparation method and photovoltaic cell TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic technology, in particular to an electrode grid line preparation method and photovoltaic cell. BACKGROUND

[0002] Currently in the world, burning coal is still the main power generation method. However, with the acceleration of industrialization and the increasing energy consumption, the reserves of non-renewable resources such as coal are gradually decreasing, and its mining and use have caused increasingly serious negative impacts on the environment. Therefore, in order to reduce the dependence on fossil fuels and promote sustainable development, countries have sought alternative solutions for renewable energy, among which solar energy as a promising clean energy has received widespread attention. Photovoltaic silver paste as a key material for solar cells has an important influence on the performance of the cells. By optimizing the coating process of photovoltaic silver paste on solar silicon wafers, the electrical conductivity and photoelectric conversion efficiency of solar cells can be significantly improved.

[0003] Currently, in industrialized production, screen printing technology is mainly used to coat electrodes on photovoltaic cells. Although screen printing technology is widely used due to its suitability for large-scale production, it still faces a series of technical challenges in practical applications. First of all, insufficient printing precision is a major problem. Due to changes in printing parameters and instability in the process, the width and thickness of the silver paste are often uneven, and this unevenness can lead to an increase in cell resistance, which in turn affects cell performance. In addition, screen printing technology is difficult to achieve high-resolution pattern printing below 10 microns, which limits its effectiveness in more delicate applications.

[0004] Secondly, the problem of waste generated during the screen printing process is also an important challenge. The waste of silver paste not only increases production costs, but also brings environmental burdens. Safety issues cannot be ignored either, as solvents and materials used in screen printing can release harmful or irritating dust and gases, which pose potential threats to the health of operators and the environment. Finally, screen printing has low production efficiency, high cleanliness requirements for the production environment, and its relatively slow process speed cannot meet the needs of large-scale production.

[0005] Therefore, it is necessary to develop an electrode grid line printing technology with high printing precision, low production cost, high production efficiency and safety, to promote the sustainable development of photovoltaic cell production. SUMMARY

[0006] In order to develop an electrode grid line printing technology with high printing precision, low production cost and high production efficiency, the present application provides an electrode grid line preparation method and photovoltaic cell.

[0007] The electrode grid line preparation method and the photovoltaic cell adopt the technical solutions as follows:

[0008] The electrode grid line preparation method comprises the following steps: S1, providing a substrate, and forming a polymer layer on the substrate; S2, providing a mold corresponding to a required electrode pattern, and pressing a groove corresponding to the electrode pattern on the polymer layer through the mold; S3, smearing a conductive material on the polymer layer, so that the conductive material fills the groove, and the excess conductive material is scraped off; S4, drying the conductive material; S5, after drying, dissolving the polymer layer; and S6, sintering the conductive material to form the electrode grid line.

[0009] By adopting the above technical solutions, the process of scraping and coating the conductive material is accurately controlled through the design of the mold and the groove, so that the thickness of the conductive material can be effectively controlled, and the performance reduction caused by uneven thickness can be avoided. The method can form a fine electrode pattern of several microns on the substrate, thereby ensuring the high precision and high consistency of the electrode grid line. Moreover, the method almost generates no waste, greatly reduces the amount and cost of the conductive material, and the saved conductive material can reduce the production cost and improve the economic benefit. The method has a simple process and high process precision, can realize rapid production, improve the production efficiency, meet the needs of industrial production, and can be combined with the concept of green and sustainable development, thereby helping to promote the application of the environment-friendly production process.

[0010] In a specific implementation solution, in the step S2, the thickness of the residual layer after the pressing is 0.5-2 microns.

[0011] By adopting the above technical solutions, a distance of 0.5-2 microns is left between the groove and the substrate during the process of pressing the groove through the mold, so that the mold and the substrate can be prevented from directly contacting each other, thereby reducing the risk of substrate rupture caused by mechanical stress, helping to maintain the integrity of the substrate during work, and improving the stability and reliability of the entire system.

[0012] In a specific implementation solution, between the step S2 and the step S3, the method further comprises a step S2-1 of removing part of the polymer layer, so that the groove bottom wall and the top surface of the substrate are on the same horizontal plane.

[0013] By adopting the above technical solutions, the height of the polymer layer is weakened, so that the groove bottom and the substrate are on the same plane, and the conductive material smearing in the groove can directly contact the substrate, thereby enhancing the conductive performance and contact quality of the conductive material, and ensuring that the conductive material can form a more stable electrode structure, thereby improving the production efficiency and the yield.

[0014] In a specific implementation solution, in the step S2-1, the polymer layer is etched by a reactive ion etching technology to remove part of the polymer layer.

[0015] By adopting the technical scheme, the reactive ion etching technology can accurately remove part of the polymer layer, ensure that the groove bottom wall and the top surface of the substrate are on the same horizontal plane, the reactive ion etching can remove the polymer layer in a short time, and uniform etching effect can be provided, the surface quality of the groove bottom is maintained, so that the conductive material can directly contact the substrate, and the conductive performance is improved.

[0016] In a specific embodiment, in S2, the groove is hot-pressed on the polymer layer by the mold, and the hot-pressing temperature is 100-180℃.

[0017] By adopting the technical scheme, the polymer layer can be uniformly pressed into the mold in this temperature range, so that a clear and accurate groove structure is formed, the quality and consistency of the product are improved, the relatively low hot-pressing temperature can reduce the thermal damage to the polymer layer, avoid polymer degradation or failure caused by excessively high temperature, maintain the performance and stability of the material, and thus improve the production efficiency and product consistency.

[0018] In a specific embodiment, in S4, the drying temperature of the conductive material is 100-200℃.

[0019] By adopting the technical scheme, the conductive material can be sufficiently dried in this temperature range to form a stable conductive layer, which helps to enhance the adhesion of the conductive material to the substrate, reduces the risk of peeling or falling off, and improves its electrical performance and conductivity.

[0020] In a specific embodiment, the material of the polymer layer is a water-soluble polymer material.

[0021] By adopting the technical scheme, the water-soluble polymer material can be processed by simple dissolution and coating process, which simplifies the production process, and because water is used as the solvent, these materials are more environmentally friendly, reducing the use of organic solvents and waste disposal problems.

[0022] In a specific embodiment, the water-soluble polymer material is one of polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, modified polyvinyl alcohol, sodium polyacrylate, polyvinyl alcohol-polyacrylic acid, and polyvinyl alcohol-polyacrylonitrile.

[0023] In a specific embodiment, in S5, hot water at 60-80℃ is used to dissolve the polymer layer.

[0024] By adopting the above technical scheme, the dissolution process of the polymer is accelerated by using high temperature, the processing time is shortened, the production efficiency is improved, and hot water helps to overcome the crystalline structure of the polymer, so that it is more uniformly dissolved to form a more stable solution.

[0025] In one specific implementation, the sintering temperature of the conductive material is 600-800℃.

[0026] By adopting the above technical scheme, the particles of the conductive layer are firmly connected by high-temperature sintering, the interlayer bonding force is improved, the peeling problem is reduced, the mechanical strength and stability of the overall structure are enhanced, and at high temperature, the particles in the conductive material can be effectively fused, the electrical conductivity is significantly improved, and the conductive performance is optimized.

[0027] In one specific implementation, the substrate is one of single crystal silicon, polycrystalline silicon, gallium arsenide, cadmium telluride, and amorphous silicon film.

[0028] In one specific implementation, the conductive material is one of silver paste, copper paste, and aluminum paste, and mixtures thereof.

[0029] By adopting the above technical scheme, the silver paste can provide excellent electrical conductivity, help to reduce the resistance of electronic devices, improve performance and efficiency, and provide efficient and stable conductive performance, while adapting to different substrates and manufacturing processes to meet the needs of high-performance electronic products.

[0030] In one specific implementation, the longitudinal cross-sectional shape of the groove is one of rectangular and trapezoidal.

[0031] In one specific implementation, the substrate of the mold is one of single crystal silicon substrate, polycrystalline silicon substrate, glass substrate, quartz substrate, polymer substrate, copper substrate, nickel substrate, copper-nickel alloy substrate, nickel-iron alloy substrate, iron-aluminum alloy substrate, and aluminum alloy substrate.

[0032] A photovoltaic cell comprising the electrode grid line prepared by the preparation method described above.

[0033] By adopting the technical scheme, the electrode grid line prepared by the preparation method has high precision, high conductivity, good surface finish, optimized heat management, and enhanced mechanical strength and durability, comprehensively improving the performance, efficiency and long-term stability of the photovoltaic cell; the precise groove is pressed on the polymer layer by the mold, ensuring the high precision of the electrode grid line pattern, and the precise patterning helps to optimize the photoelectric conversion efficiency and current collection capability of the photovoltaic cell; the conductive material is filled and subjected to two treatments of drying and sintering, so that the electrode grid line has excellent conductivity, and the electrode grid line with high conductivity can effectively collect the current generated by the cell, reduce resistance and energy loss, thereby improving the overall power output of the cell; the preparation method supports different electrode pattern designs, so that the structure of the electrode grid line can be optimized according to the specific needs of the photovoltaic cell, and the flexible design can improve the photoelectric conversion efficiency and adapt to different application scenarios.

[0034] In a specific implementable embodiment, the longitudinal cross-sectional shape of the electrode grid line is rectangular or trapezoidal, the height of the rectangle is 10±2 μm, the aspect ratio of the rectangle is 2:1, the base angle of the trapezoid is 30°-70°, the height of the trapezoid is 10±2 μm, and the aspect ratio of the trapezoid is 2:1.

[0035] In summary, the beneficial technical effects of the present application are: the present application accurately controls the process of scraping and coating the conductive material through the design of the mold and the groove, can effectively control the thickness of the conductive material, avoid performance reduction caused by uneven thickness, and can form a small electrode pattern of several microns on the substrate, ensuring the high precision and consistency of the electrode grid line; and the method generates almost no waste, greatly reducing the amount and cost of conductive material, and the saved conductive material can reduce production cost and improve economic benefit;

[0036] The method has a simple process flow, high process precision, can realize rapid production, improve production efficiency, meet the needs of industrial production, and can be combined with the concept of green and sustainable development, which is helpful to promote the application of environmentally friendly production processes; and the electrode grid line prepared by the preparation method has high precision, high conductivity, good surface finish, optimized heat management, and enhanced mechanical strength and durability, which comprehensively improves the performance, efficiency and long-term stability of the photovoltaic cell. BRIEF DESCRIPTION OF DRAWINGS

[0037] Fig. 1 is a process flow diagram of the electrode grid line preparation method of the embodiment of the present application.

[0038] Explanation of reference signs: 1, substrate; 2, polymer layer; 3, mold; 4, groove; 5, conductive material; 6, electrode grid line. DETAILED DESCRIPTION

[0039] The application will be further described in detail below with reference to FIG. 1.

[0040] Referring to FIG. 1, the application discloses a method for preparing an electrode grid line, which comprises the following steps:

[0041] S1, providing a substrate 1, forming a polymer layer 2 on the substrate 1 by coating a polymer solution; before coating, it is necessary to ensure that the surface of the substrate 1 is clean, flat and free of contamination, so as to ensure the quality of the subsequent coating process, and surface treatment is performed on the substrate 1 to enhance the adhesion of the polymer layer 2;

[0042] In this embodiment, the polymer solution is coated on the substrate 1 by using a flat plate coating method, and after drying, a polymer layer 2 is obtained; the flat plate coating method includes being realized by spin coating, blade coating or spraying coating and the like, and the specific selection depends on the properties of the polymer used and the required thickness, and the coating rate and uniformity need to be controlled during the coating process, so as to ensure the uniform thickness of the polymer layer 2;

[0043] Specifically, before coating, the substrate 1 is subjected to necessary pretreatment, and the pretreatment method includes cleaning, drying and surface activation, removes the contaminants on the surface of the substrate 1, increases the surface roughness, and improves the adhesion of the polymer layer 2;

[0044] The uniform polymer solution is coated on the substrate 1, the uniformity and thickness of the coating are controlled, and after the coating is completed, the polymer layer 2 is dried or cured under the environmental conditions of 90-110°C, so as to ensure that its physical and chemical properties meet the requirements, and in this embodiment, according to the properties of the polymer and the application requirements, further curing treatment can be performed, including but not limited to heating in an oven, so as to further cross-link and harden the polymer layer 2;

[0045] The material of the substrate 1 includes but is not limited to one of single crystal silicon, polycrystalline silicon, gallium arsenide, cadmium telluride and amorphous silicon film, and in this embodiment, the material of the substrate 1 is preferably polycrystalline silicon; the silicon wafer has good electronic conductivity and stability, and has good thermal stability and thermal conductivity, and is suitable for the manufacture of various electronic devices.

[0046] In this embodiment, the material of the polymer layer 2 is a water-soluble polymer material, and the water-soluble polymer material is one of polyvinyl alcohol (PVA), polyparaline ketone (PVP), polyethylene glycol (PEG), modified polyvinyl alcohol (PVA), polyacrylic acid sodium (PAA-Na), polyvinyl alcohol-polyacrylic acid (PVA-PAA), and polyvinyl alcohol-polyacrylonitrile (PVA-PAN). In this embodiment, the material of the polymer layer 2 is preferably polyvinyl alcohol. Polyvinyl alcohol is insoluble in organic solvents such as acetone, methanol, and gasoline. Polyvinyl alcohol can be processed by a simple dissolving and coating process, simplifying the production process. Moreover, since water is used as the solvent, these materials are more environmentally friendly, reducing the use of organic solvents and waste disposal problems.

[0047] S2, providing a mold 3 corresponding to the required electrode pattern. In this embodiment, a mold 3 matching the required electrode pattern is prepared. The base material of the mold 3 includes but is not limited to one of single-crystal silicon base material, polycrystalline silicon base material, glass base material, quartz base material, polymer base material, copper base material, nickel base material, copper-nickel alloy base material, nickel-iron alloy base material, iron-aluminum alloy base material, and aluminum alloy base material. The surface of the mold 3 needs to be accurately engraved or processed into the required electrode pattern. These patterns represent the shape and layout of the electrodes, including the required grooves 4, protrusions, and other structural details.

[0048] Specifically, the mold 3 is aligned with the substrate 1 coated with the polymer layer 2, ensuring that the pattern of the mold 3 accurately docks with the position on the polymer layer 2, and the grooves 4 corresponding to the electrode pattern are pressed out on the polymer layer 2 by the mold 3. The mold 3 is pressed on the polymer layer 2 by a hot pressing process. The hot pressing temperature includes but is not limited to being set between 100-180°C. Preferably, the optimal hot pressing forming conditions are: the hot pressing temperature is 130-160°C, the hot pressing pressure is 10MPa, and the hot pressing time is 2min. Under these conditions, the grooves 4 can be well hot-pressed. Within this temperature and pressure range, the polymer layer 2 becomes soft enough, so that the pattern of the mold 3 can be accurately imprinted on the polymer layer 2, to ensure that the polymer layer 2 can uniformly form the required groove 4 structure during hot pressing, while avoiding excessive heating that can cause degradation or flow of the polymer layer 2.

[0049] Within this temperature and pressure range, the polymer layer 2 can be uniformly pressed into the mold 3, thereby forming clear and accurate groove 4 structures, improving the quality and consistency of the product. A relatively low hot pressing temperature can reduce the thermal damage to the polymer layer 2, avoid degradation or failure of the polymer due to excessive temperature, and maintain the performance and stability of the material, thereby improving production efficiency and product consistency.

[0050] After the hot pressing is completed, the thickness D of the embossed residual layer is 0.5-2 μm, that is, a certain distance D should be reserved between the groove bottom of the groove 4 and the substrate 1, the distance D is 0.5-2 μm, this distance can effectively avoid the direct contact between the film 3 and the substrate 1, thereby reducing the risk of substrate 1 rupture caused by mechanical stress, helping to maintain the integrity of the substrate 1 during work, and improving the stability and reliability of the entire system;

[0051] After these steps are completed, the mold 3 is removed, and the polymer layer 2 can be subsequently processed according to actual needs, such as hardening or cleaning, to ensure the clarity and stability of the groove 4, and finally form an electrode pattern that meets the design requirements.

[0052] The longitudinal cross-sectional shape of the groove 4 includes but is not limited to one of a rectangle, a trapezoid, in this embodiment, the longitudinal cross-sectional shape of the groove 4 is a rectangle, the height-width ratio of the rectangle is 2:1, the groove 4 is designed as a rectangular cross-sectional geometry, which simplifies the process and ensures uniform filling of the conductive material 5; in addition, the edges of the rectangular groove 4 are sharp, which can better ensure the contact and conductivity of the electrode, while reducing the gaps or material deficiencies that occur during filling.

[0053] S2-1: After the hot pressing process is completed, further processing of the polymer layer 2 is performed to remove part of the polymer layer 2, so that the groove bottom wall of the groove 4 and the top surface of the substrate 1 are on the same horizontal plane, in this process, including but not limited to weakening the height of the polymer layer 2 by reactive ion etching (RIE etching), the removed part of the polymer layer 2 is the structure between the groove bottom of the groove 4 and the substrate 1, which is 0.5-2 μm;

[0054] Specifically, a suitable RIE etching device is selected, and etching parameters are set according to the polymer material used, ensuring that the etching system is clean and ready for the required gas, such as oxygen or fluorinated gas, preferably, oxygen is selected as the gas; according to the thickness of the polymer layer 2 and the required etching depth, the power, gas flow, etching time and gas pressure of the etching are set to ensure the uniformity and accuracy of the etching; the substrate 1 is placed in the RIE etching cavity, and the etching process is started, during the etching process, reactive ions will produce chemical reactions and physical etching on the polymer surface, thereby removing part of the polymer layer 2 until the groove bottom of the groove 4 is flush with the top surface of the substrate 1; after the etching is completed, the substrate 1 is cleaned to remove residual etching by-products and impurities, in this embodiment, deionized water or other appropriate cleaning solvents can be used to ensure the surface is clean, and the uniformity and alignment of the groove 4 are checked.

[0055] The RIE etching technology can accurately remove part of the polymer layer 2, weaken the height of the polymer layer 2, ensure that the remaining polymer layer 2 in the groove 4 on the substrate 1 is etched, and expose the surface of the substrate 1. The RIE etching can remove the polymer layer 2 in a short time, provide uniform etching effect, maintain the surface quality of the groove bottom, and enable the conductive material 5 in the groove 4 to directly contact the substrate 1 after etching, thereby enhancing the conductivity and contact quality of the conductive material 5 and ensuring that the conductive material 5 can form a more stable electrode structure, thereby improving the production efficiency and yield.

[0056] S3, applying a conductive material 5 on the polymer layer 2, in this embodiment, including but not limited to using a flat coating technology to apply the conductive material 5 on the polymer layer 2, so that the conductive material 5 fills the groove 4, and the excess conductive material 5 is scraped off;

[0057] Specifically, a suitable flat coating tool such as a coating knife or a doctor blade is selected to uniformly apply the conductive material 5 on the surface of the polymer layer 2, so that the material can penetrate and fill all the grooves 4. During the coating process, special attention is paid to the filling of the groove 4 area to ensure that the conductive material 5 completely covers the bottom and sidewall of the groove 4. The flat tool (such as a doctor blade) is used to scrape off the excess conductive material 5 on the surface to keep the conductive material 5 in the groove 4 flush with the surface of the polymer layer 2. The doctor blade should be kept parallel to the surface to obtain uniform coating thickness and avoid damaging the polymer layer 2. After the coating is completed, the filling effect is checked to ensure that the conductive material 5 in the groove 4 is uniform and has no omissions. If necessary, the unnecessary material is removed or the uneven area is repaired.

[0058] The conductive material 5 is one of silver paste, copper paste, and aluminum paste, and a mixture thereof. In this embodiment, the conductive material 5 is preferably silver paste. The silver paste can provide excellent electrical conductivity, help reduce the resistance of electronic devices, improve performance and efficiency, and provide efficient and stable conductivity while adapting to different substrates and manufacturing processes to meet the needs of high-performance electronic products.

[0059] In this embodiment, the material of the polymer layer 2, polyvinyl alcohol, does not react with the organic solvent in the silver paste of the conductive material 5, so that the polymer layer 2 and the conductive material 5 do not adhere to each other, so that the silver paste of the conductive material 5 can maintain its own shape and reduce the influence of different shapes of the conductive material 5 on its conductivity.

[0060] S4, drying the conductive material 5. The conductive material 5 is dried by an oven, and the drying temperature of the conductive material 5 is 100-200°C. This temperature range can ensure that the conductive material 5 is sufficiently dried to form a stable conductive layer, help enhance the adhesion of the conductive material 5 to the substrate 1, reduce the risk of peeling or falling off, and improve its electrical properties and conductivity.

[0061] Specifically, according to the type of conductive material 5 and the manufacturer's recommendations, the temperature of the oven is set between 100°C and 200°C, which is generally suitable for most conductive materials 5 drying, ensuring sufficient drying of the material without overheating or damage; the sample coated with conductive material 5 is carefully placed in the oven, the oven timer is set to ensure that the sample is dried at the set temperature for a sufficient period of time, the drying time is determined according to the specific requirements of the conductive material 5 and the layer thickness, usually 0.5min-10min, following the drying time recommendations provided by the material manufacturer to ensure optimal drying results;

[0062] During the drying process, the temperature and sample status inside the oven are continuously monitored to ensure that the internal temperature of the oven remains stable and that excessive or insufficient temperature does not adversely affect the drying effect of the conductive material 5, and adjustments or corrections are made in a timely manner if temperature fluctuations or other abnormalities occur; after the drying time is up, the sample is removed from the oven and the drying effect of the conductive material 5 is checked to ensure that the material is evenly dried without bubbles, peeling or other defects, and the drying quality can be evaluated by visual inspection or using appropriate test methods.

[0063] S5, after drying, the polymer layer 2 is dissolved, including but not limited to using 60-80°C hot water to dissolve the polymer layer 2, in this embodiment, 70°C hot water is used to dissolve the polymer layer 2; higher temperature hot water accelerates the dissolution process of the polymer, shortens the processing time, improves the production efficiency, and the hot water helps to overcome the crystalline structure of the polymer, making it more evenly dissolved to form a more stable solution;

[0064] Specifically, after drying, the dried sample is carefully placed in 70°C hot water, ensuring that the polymer layer 2 is completely immersed, and the polymer layer 2 will gradually dissolve in the 70°C hot water, and the sample is checked periodically to observe the dissolution of the polymer layer 2;

[0065] When the polymer layer 2 is completely dissolved, the sample is removed from the hot water, the sample can be rinsed with water to remove any remaining polymer solution, and the sample is then placed in a dry environment to ensure complete drying to avoid moisture affecting subsequent processing. Check the sample after removing the polymer layer 2 to confirm the integrity and surface quality of the conductive material 5, ensuring that there is no damage or material missing to ensure that subsequent applications and integration can proceed smoothly.

[0066] S6, further sintering the conductive material 5 to form a continuous and intact electrode grid line 6, the sintering temperature of the conductive material 5 is 600-800°C;

[0067] Specifically, but not limited to, the selection of appropriate sintering furnace, the temperature of the sintering furnace is set between 600-800℃, this temperature range can be applied to the sintering of conductive material 5, to ensure that it reaches the required electrical conductivity and structural strength; the processed sample is carefully placed into the sintering furnace, the sintering furnace is started, and gradually heated to the set temperature, during the heating process, the temperature is kept stable to ensure uniform sintering of the conductive material 5, the heating time is usually determined according to the thickness of the material and specific requirements; after the sintering process is completed, gradually reduce the temperature in the furnace to room temperature, avoid rapid cooling, to prevent the material from cracking or deforming due to thermal stress, after cooling, check the formed electrode grid line 6, ensure that its structure is complete, the electrical conductivity meets the requirements, check whether there is any sintering uneven or material defects;

[0068] The use of high-temperature sintering forms a firm connection between the particles of the conductive layer, improves the interlayer bonding force, reduces the peeling problem, thereby enhancing the mechanical strength and stability of the overall structure, and at high temperature, the particles in the conductive material 5 can effectively fuse, significantly improve the electrical conductivity, and optimize the electrical conductivity.

[0069] The application also provides a photovoltaic cell comprising the electrode grid line 6 prepared by the above-mentioned preparation method;

[0070] The longitudinal cross-sectional shape of the electrode grid line 6 includes but is not limited to a rectangle or a trapezoid; wherein the height of the rectangle is 10±2μm, and the aspect ratio of the rectangle is 2:1; the base angle of the trapezoid is 30°-70°, the height of the trapezoid is 10±2μm, and the aspect ratio of the trapezoid is 2:1; the optimal shape of the electrode grid line 6 should be comprehensively considered according to the type, size, material and other aspects of the photovoltaic cell, so as to provide a larger contact area, reduce resistance, and more uniform current distribution, which can reduce the hot spot problem, improve the overall efficiency, and better control the propagation direction of light, reduce reflection loss, increase light absorption, and help to improve the path length of light in the cell, thereby increasing the light absorption efficiency;

[0071] The electrode grid lines 6 prepared by the above method bring high precision, high conductivity, good surface finish, optimized thermal management, and enhanced mechanical strength and durability to the photovoltaic cells, comprehensively improving the performance, efficiency, and long-term stability of the photovoltaic cells; the precise grooves 4 pressed on the polymer layer 2 using the mold 3 ensure the high precision of the electrode grid line 6 pattern, and this precise patterning helps to optimize the photoelectric conversion efficiency and current collection capability of the photovoltaic cells; the conductive material 5 is filled and subjected to two processes of drying and sintering, so that the electrode grid lines 6 have excellent conductivity, and the electrode grid lines 6 with high conductivity can effectively collect the current generated by the cells, reduce resistance and energy loss, and thus improve the overall power output of the cells; the preparation method supports different electrode pattern designs, so that the structure of the electrode grid lines 6 can be optimized according to the specific needs of the photovoltaic cells, and flexible design can improve the photoelectric conversion efficiency and adapt to different application scenarios.

[0072] The implementation principle of the embodiments of the present application is that the process of squeegee coating the conductive material 5 is accurately controlled through the design of the mold 3 and the groove 4, which can effectively control the thickness of the conductive material 5 and avoid performance degradation caused by uneven thickness. This method can form a fine electrode pattern of several microns on the substrate 1, ensuring the high precision and high consistency of the electrode grid lines 6. Moreover, this method generates almost no waste, greatly reducing the amount and cost of the conductive material 5. The saved conductive material 5 can reduce production costs and improve economic benefits. The method has a simple process and high process precision, can realize rapid production, improve production efficiency, meet the needs of industrial production, and can be consistent with the concept of green and sustainable development, which helps to promote the application of environmentally friendly production processes.

[0073] The above are preferred embodiments of the present application, which do not limit the protection scope of the present application, therefore: any equivalent changes made on the basis of the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A method of making an electrode grid, the method comprising: The method comprises the following steps: S1, providing a substrate and forming a polymer layer on the substrate; S2, providing a mold corresponding to a desired electrode pattern, and pressing a groove corresponding to the electrode pattern on the polymer layer through the mold; S3, applying a conductive material on the polymer layer, so that the conductive material fills the groove, and the excess conductive material is scraped off; S4, drying the conductive material; S5, dissolving the polymer layer after drying; S6, sintering the conductive material to form the electrode grid lines. ​ 2. The method of claim 1, wherein: In the step S2, the residual layer thickness after pressing is 0.5-2 μm.

3. The method of claim 2, wherein: Between the steps S2 and S3, the step S2-1 of removing part of the polymer layer is further included, so that the groove bottom wall is on the same horizontal plane as the top surface of the substrate.

4. The method of claim 3, wherein: In the step S2-1, the polymer layer is etched by a reactive ion etching technology to remove part of the polymer layer.

5. The method of claim 1, wherein: In the step S2, the groove is hot-pressed on the polymer layer through the mold, and the hot-pressing temperature is 100-180 ℃.

6. The method of claim 1, wherein: In the step S4, the drying temperature of the conductive material is 100-200 ℃.

7. The method of claim 1, wherein: The material of the polymer layer is a water-soluble high polymer material.

8. The method of claim 7, wherein: The water-soluble high polymer material is one of polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, modified polyvinyl alcohol, sodium polyacrylate, polyvinyl alcohol-polyacrylic acid, and polyvinyl alcohol-polyacrylonitrile.

9. The method of claim 1, wherein: In the step S5, the polymer layer is dissolved by hot water at 60-80 ℃.

10. The method of claim 1, wherein: In the step S6, the sintering temperature of the conductive material is 600-800 ℃.

11. The method of claim 1, wherein: The material of the substrate is one of single crystal silicon, polycrystalline silicon, gallium arsenide, cadmium telluride, and amorphous silicon film.

12. The method of claim 1, wherein: The conductive material is one of silver paste, copper paste, and aluminum paste, or a mixture thereof.

13. The method of claim 1, wherein: The longitudinal cross-sectional shape of the groove is one of a rectangle and a trapezoid.

14. The method of claim 1, wherein: The base material of the mold is one of single crystal silicon base material, polycrystalline silicon base material, glass base material, quartz base material, polymer base material, copper base material, nickel base material, copper-nickel alloy base material, nickel-iron alloy base material, iron-aluminum alloy base material, and aluminum alloy base material.

15. A photovoltaic cell, characterized by: The electrode grid lines are prepared by the preparation method according to any one of claims 1-14.

16. The photovoltaic cell of claim 15, wherein: The longitudinal cross-sectional shape of the electrode grid lines is a rectangle or a trapezoid, the height of the rectangle is 10±2 μm, the height-width ratio of the rectangle is 2:1, the bottom angle of the trapezoid is 30°-70°, the height of the trapezoid is 10±2 μm, and the height-width ratio of the trapezoid is 2:1.

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