Photovoltaic electrode grid line preparation method and photovoltaic cell

Abstract

The invention discloses a photovoltaic electrode grid line preparation method and a photovoltaic cell, and relates to the technical field of photovoltaic cells. The preparation method of the photovoltaic electrode grid line comprises the following steps: providing a preset mold which is complementary with an electrode pattern to be embossed and formed in shape; preparing a required polymer layer on the mold according to preset process parameters, and taking the required polymer layer as a transfer printing substrate; coating the forming side of the polymer layer with conductive slurry which at least can fill the grooves in the polymer layer, and removing redundant conductive slurry on the surface of the polymer layer, so that the surfaces of the grooves and the conductive slurry are located on the same plane; a required polymer layer is prepared on a mold according to preset process parameters and serves as a transfer printing substrate, and then the polymer layer is subjected to transfer printing, dissolution and other processes, so that precise and high-resolution electrode grid line preparation is realized on a base material, mold damage caused by repeated impressing and demolding is solved, and the production efficiency is improved. And the service life of the die is shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic cells, and in particular to a method for preparing a photovoltaic electrode grid line and a photovoltaic cell. Background Art

[0002] The work of building a new power system with new energy as the main body is being accelerated, and the status of the photovoltaic industry has been significantly improved; solar cells are the core components of photovoltaic systems, and industrial production based on single-crystal silicon photovoltaic cells occupies an important position, accounting for more than 90% of the total solar cell output; electrode grid lines are key components of batteries, and they have a great influence on the performance of solar cells; the materials of electrode grid lines are mainly materials with good electrical conductivity, and conductive paste is one of the most widely used electrode grid line materials at present, with excellent electrical conductivity and chemical stability, and is suitable for the preparation of photovoltaic cells; optimizing the preparation process of conductive paste grid lines can effectively improve the photoelectric conversion efficiency of solar cells.

[0003] Conductive paste gridline printing technology for photovoltaic cells is one of the key production processes, which is mainly used to form electrodes on silicon wafers to collect current generated by the photovoltaic effect. Common electrode gridline printing technologies mainly include: screen printing, inkjet printing, offset printing and flexible printing. Screen printing technology is the most commonly used. This technology prints conductive paste on the surface of photovoltaic cells through a screen to form an electrode pattern, thereby realizing the collection and conduction of electrical energy.

[0004] Although screen printing technology is more commonly used, it still has some shortcomings compared to transfer conductive paste technology; for example: transfer conductive paste technology has the advantages of higher resolution, more stable finished product quality, higher production efficiency, wider applicability and greater durability.

[0005] However, in the transfer technology, the transfer base film cannot meet the use requirements due to its flexibility, so some base films are too soft, resulting in deformation after the subsequent conductive paste is filled in; some base films are too hard, resulting in too brittle to be used normally; and, in the current process of high-resolution photovoltaic electrode grid lines made by high-precision hot embossing and transfer of polymer layers, due to the high aspect ratio requirements and the narrow distance between grid lines, repeated embossing and tearing with high pressure will cause damage to the mold, thereby shortening the mold life. No effective solution has been proposed for the above problems. Summary of the invention

[0006] Purpose of the invention: To provide a method for preparing a photovoltaic electrode grid line and a photovoltaic cell to at least solve one of the problems existing in the above-mentioned prior art.

[0007] Technical solution: A method for preparing a photovoltaic electrode grid line, comprising the following steps: S1. providing a mold with a preset shape complementary to the electrode pattern to be embossed; S2, preparing a desired polymer layer on the mold according to preset process parameters, and using the polymer layer as a transfer substrate; S3, coating the conductive paste on the molding side of the polymer layer to at least fill the groove thereon, and removing excess conductive paste on the surface of the polymer layer so that the groove and the surface of the conductive paste are located on the same plane; S4, providing a substrate, laminating the side of the polymer layer having the conductive paste to the substrate, and transferring the conductive paste to the substrate by a transfer method with preset process parameters; wherein the transfer process parameters are: pressure of 5-20 MPa, temperature of 80-180° C., and time of 1-10 min; S5, removing the polymer layer so that the conductive paste remains on the substrate; S6. Sintering the conductive paste on the substrate to form electrode grid lines with a preset aspect ratio.

[0008] Preferably, S2, preparing a desired polymer layer on the mold according to preset process parameters and using the polymer layer as a transfer substrate, comprising: A polymer layer with a thickness of 15-85 μm and grooves is prepared on the mold, and after drying at 100-125° C., it is demoulded from the mold side to obtain a polymer layer with the desired micrometer-scale or nanometer-scale electrode pattern as a transfer substrate.

[0009] Preferably, in S2, the thickness of the polymer layer is 15-50 μm.

[0010] Preferably, in S2, the polymer layer is prepared by electrospinning or flat coating.

[0011] Preferably, in S1, the mold is one of a single crystal silicon substrate, a polycrystalline silicon substrate, a copper substrate, a nickel substrate, a copper-nickel alloy substrate, a nickel-iron alloy substrate, an iron-aluminum alloy substrate or an aluminum alloy substrate.

[0012] Preferably, in S1, the convex portion of the mold is complementary in shape to the concave portion; Wherein, the shape of the mold is one of an isosceles triangle, an isosceles trapezoid, an ellipse, a hexagon, a right-angled trapezoid or a rectangle.

[0013] Preferably, in S1, the aspect ratio of the mold shape is in the range of 1-3.

[0014] Preferably, in S1, the surface of the mold is coated with a self-assembled monolayer.

[0015] Preferably, the self-assembled monolayer is one of a silane compound, a siloxane compound or a perfluorinated compound.

[0016] Preferably, S3, coating the forming side of the polymer layer with a conductive paste that can fill the groove thereon, and removing excess conductive paste on the surface of the polymer layer so that the groove and the surface of the conductive paste are located on the same plane, comprising: The conductive paste is evenly applied on the formed polymer layer by a flat coating method so that the conductive paste completely fills the groove, and the excess conductive paste is scraped off to ensure that the conductive paste is completely filled and evenly distributed without deformation.

[0017] Preferably, S4, providing a substrate, and laminating the side of the polymer layer having the conductive paste to the substrate, comprising: At a preset temperature, by applying isotropic pressure, the conductive paste is tightly attached to the surface of the substrate while drying the conductive paste; and within the temperature and pressure range, the macroscopic morphology of the conductive paste transferred to the substrate does not change; Wherein, the substrate is one of crystalline silicon wafer, glass, perovskite, metal or polymer substrate.

[0018] Preferably, S5, removing the polymer layer so that the conductive paste remains on the substrate, comprises: The transferred silicon wafer is placed in an aqueous solution at 25-75°C to dissolve and peel off the polymer layer, leaving behind the successfully transferred conductive paste pattern to form the basic structure of the photovoltaic electrode grid line.

[0019] Preferably, S6, sintering the conductive paste on the substrate to form electrode grid lines with a preset aspect ratio, comprising: The silicon wafer after the conductive paste is transferred is placed in a high-temperature furnace to sinter the conductive paste; the sintering temperature is 500-800℃, ensuring that the conductive paste is completely sintered and forms a tight connection with the silicon wafer to generate electrode grid lines with a preset aspect ratio.

[0020] Preferably, the conductive paste is one of silver paste, aluminum paste, copper paste, chromium paste, tin paste, indium paste, nickel paste, titanium paste or tantalum paste. Preferably, the glass transition temperature of the polymer layer is 60-120° C., and the material of the polymer layer is a water-soluble polymer material.

[0021] Preferably, the water-soluble polymer material is one of polyvinyl pyrrolidone, polyethylene glycol, polyvinyl alcohol, sodium polyacrylate, polyvinyl alcohol-polyacrylic acid or polyvinyl alcohol-polyacrylonitrile; The average polymerization degree of the polyvinyl alcohol is 1700, and the alcoholysis degree is 88-92%; the polyvinyl alcohol is ordinary polyvinyl alcohol and modified polyvinyl alcohol; the modified polyvinyl alcohol is carboxyl-modified polyvinyl alcohol, and the carboxyl modification degree is 2-8%.

[0022] Preferably, S2 further includes: a bonding layer is provided on a side of the polymer layer away from the mold, and a substrate is provided on a side of the bonding layer away from the polymer layer.

[0023] Preferably, the substrate is one of polyimide, polyethylene terephthalate, polyamide or polycarbonate.

[0024] Preferably, S4 further includes: when the transfer is performed under preset process parameters, the adhesive layer and the substrate are separated from the polymer layer.

[0025] In order to achieve the above objective, according to another aspect of the present application, a photovoltaic cell is provided.

[0026] The photovoltaic cell according to the present application includes the prepared photovoltaic electrode grid lines.

[0027] Beneficial effect: In the embodiment of the present application, a method of directly preparing a polymer layer on a mold and transferring to prepare photovoltaic electrode grid lines is adopted, through S1, providing a mold with a preset shape complementary to the electrode pattern to be embossed; S2, preparing the required polymer layer on the mold according to preset process parameters, and using it as a transfer substrate; S3, coating the forming side of the polymer layer with a conductive paste that can at least fill the groove thereon, and removing excess conductive paste on the surface of the polymer layer so that the groove and the surface of the conductive paste are located on the same plane; S4, providing a substrate, laminating the side of the polymer layer having the conductive paste to the substrate, and transferring the conductive paste to the substrate by a transfer method with preset process parameters; wherein the process parameters of the transfer are: pressure of 5-20MPa, temperature of 80-180℃ and time of 1-10min; S5, removing the polymer layer so that the conductive paste remains on the substrate; S6, transferring the conductive paste It is sintered on a substrate to form an electrode grid line with a preset aspect ratio, thereby achieving the purpose of obtaining the required polymer layer and preparing the photovoltaic electrode grid line, thereby realizing the technical effects of saving process time, simplifying the process flow, improving the service life of the mold, and ensuring that the base film has good flexibility and is easy to detach. This solves the problem that in the transfer technology, the transfer base film cannot meet the use requirements due to its flexibility, so that some base films are too soft, resulting in deformation after the subsequent conductive slurry is filled in; some base films are too hard and too brittle to be used normally; the subsequent substrate cannot be automatically separated from the substrate, thereby affecting the grid line structure; and, in the current process of making high-resolution photovoltaic electrode grid lines through a combination of high-precision hot embossing and transfer printing of the polymer layer, due to the high aspect ratio requirement and the narrow distance between the grid lines, repeated embossing and tearing of the film with large pressure will cause damage to the mold, thereby shortening the service life of the mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic flow chart of a preferred method for preparing photovoltaic electrode grid lines of the present invention; Figure 2 It is a schematic diagram of another process of preparing a photovoltaic electrode grid line of the present invention. Figure 3 It is a schematic diagram of the process of preparing the photovoltaic electrode grid line of the present invention; Figure 4 is a schematic flow chart of a method for preparing a polymer layer of the present invention; and Figure 5 It is a schematic diagram of the mold structure in the photovoltaic electrode grid line preparation method of the present invention.

[0029] The accompanying drawings are marked as follows: 1. Mould; 2. Polymer layer; 3. Groove; 4. Conductive paste; 5. Base material; 6. Electrode grid lines; 7. Adhesive layer; 8. Base. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0034] like Figure 1-4 As shown, the present application relates to a method for preparing a photovoltaic electrode grid line and a photovoltaic cell. Figure 1 and 3 As shown, a method for preparing a photovoltaic electrode grid line comprises the following steps: S1, providing a mold 1 with a preset shape complementary to the electrode pattern to be embossed; The desired polymer layer can be obtained, thereby providing a guarantee for subsequent processes.

[0035] It should be known that PVP is polyvinylpyrrolidone, which, as a non-ionic polymer compound, has good water solubility, biocompatibility and film-forming properties.

[0036] The present invention is based on a deep understanding of photovoltaic conductive pastes and a study of the water solubility of polyvinyl pyrrolidone (PVP) materials. It is found that PVP has no reactivity and weak adhesion with conductive paste adhesives and solvents, and can serve as an ideal carrier for transfer conductive pastes.

[0037] As a synthetic water-soluble polymer compound, PVP has the general properties of water-soluble polymer compounds, such as colloid protection, film-forming, adhesiveness, hygroscopicity, solubilization or coagulation, but its most distinctive feature is its excellent solubility and physiological compatibility. Among synthetic polymers, PVP is rare, which is soluble in water and most organic solvents, has low toxicity and good physiological compatibility. Especially in the fields of medicine, food, and cosmetics that are closely related to health, with the reduction of the price of its raw material butyrolactone, PVP shows a good prospect for its development.

[0038] PVP with a larger molecular weight has no obvious adhesion and reactivity with the conductive paste, which satisfies the function of PVP as a conductive paste carrier. When applying conductive paste on PVP, the conductive paste remaining on the surface can be scraped clean, ensuring that the properties of the conductive paste in the groove remain unchanged.

[0039] The glass transition temperature of PVP is 80-120°C. It is easy to meet the processing conditions by applying a certain temperature (80-160°C) and pressure (5-20MPa) to transfer it to the silicon wafer.

[0040] According to an embodiment of the present invention, preferably, in S1, the mold is one of a single crystal silicon substrate, a polycrystalline silicon substrate, a copper substrate, a nickel substrate, a copper-nickel alloy substrate, a nickel-iron alloy substrate, an iron-aluminum alloy substrate or an aluminum alloy substrate.

[0041] It is possible to achieve the effect of having a variety of materials to choose from, thereby achieving the effect of flexible use, and then the effect can be easily achieved.

[0042] It is important to know that monocrystalline silicon substrates: have excellent thermal stability and are often used in the manufacture of high-efficiency photovoltaic cells; Polycrystalline silicon substrate: relatively low cost, high mechanical strength and stability, widely used in the photovoltaic field; Copper substrate: has good electrical and thermal conductivity, suitable for applications that require fast electrical conduction; Nickel substrate: has excellent corrosion resistance and mechanical strength, suitable for long-term electrode manufacturing; Copper-nickel alloy substrate: combines the electrical conductivity of copper and the corrosion resistance of nickel, suitable for demanding electrical equipment; Nickel-iron alloy substrate: It is magnetic and corrosion-resistant, and is often used in the manufacture of electromagnetic devices; Iron-aluminum alloy substrate: lightweight, high temperature and corrosion resistant, suitable for electrode applications in aerospace and high temperature environments; Aluminum alloy substrate: light weight, good thermal conductivity, widely used in photovoltaic cell frames and electrical conductors.

[0043] S2, preparing the required polymer layer 2 on the mold 1 according to preset process parameters, and using it as a transfer substrate; By directly preparing a polymer layer with micrometer-scale or even nanometer-scale grooves on the mold and using it as a transfer substrate, the production process can be simplified, production costs can be reduced, and production efficiency can be improved.

[0044] According to an embodiment of the present invention, preferably, S2, preparing a required polymer layer 2 on the mold 1 according to preset process parameters and using the polymer layer 2 as a transfer substrate, comprises: A polymer layer with a thickness of 15-85 μm and grooves 3 is prepared on the mold, and after drying at 100-125° C., it is demoulded from the mold side to obtain a polymer layer with the desired micrometer-scale or nanometer-scale electrode pattern as a transfer substrate.

[0045] According to an embodiment of the present invention, preferably, in S2, the thickness of the polymer layer 2 is 15-50 μm. Preferably, the thickness of the polymer layer is 20-30 μm.

[0046] According to an embodiment of the present invention, preferably, in S2, the polymer layer 2 is prepared by an electrospinning method or a flat coating method.

[0047] Specifically, electrospinning is a technology that uses electrostatic force to stretch a polymer solution into nano- or micron-sized fibers, which is used to prepare polymer material films.

[0048] By adopting the electrospinning method or the flat coating method, a polymer layer with a thickness of 15-85 μm can be prepared, which can ensure good performance requirements and thus achieve a good matching effect.

[0049] Of course, those skilled in the art should be familiar with the process when the flat-plate coating method is used for preparation.

[0050] like Figure 5 As shown, according to an embodiment of the present invention, preferably, in S1, the convex portion of the mold 1 and the concave portion 3 are complementary in shape; The shape of the convex part of the mold 1 is one of an isosceles triangle, an isosceles trapezoid, an ellipse, a hexagon, a right-angled trapezoid or a rectangle. The shape and size of the convex part correspond to the electrode grid line. In actual operation, the size and shape of the electrode grid line to be transferred are controlled to reduce the ohmic loss of the electrode grid line; the longitudinal section shape of the convex part includes but is not limited to: one of a triangle, a trapezoid, a rectangle, a rhombus, a semicircle, and a polygon; in this embodiment, preferably, the longitudinal section shape of the convex part is a triangle or a trapezoid. The longitudinal section design of the triangle or trapezoid helps to change the incident and refraction path of the light, can better capture and guide the light, can effectively reduce the reflection loss of the light, so that more light is absorbed by the semiconductor material and converted into electrical energy, thereby improving the photoelectric conversion efficiency.

[0051] By designing the shapes of the convex and concave parts of the mold to be complementary structures, precise docking and embossing molding effects can be ensured during the mold molding process, thereby achieving a high-precision transfer effect and improving the quality of the electrode grid lines of the final product.

[0052] Specifically, the shape of the mold can be selected from the following geometric structures: Isosceles triangle: Suitable for scenarios that require concentrated force transmission, and can form a sharp and clear transfer effect on the edge of the photovoltaic electrode grid line.

[0053] Isosceles trapezoid: With a larger bottom width and a narrower top structure, it is suitable for applications that require electrode grid lines with gradient widths to ensure uniform filling during the transfer process.

[0054] Oval shape: It can provide smooth edge transition effect, which is suitable for electrode design that requires more uniform current distribution, reducing resistance and local stress concentration.

[0055] Hexagon: The structure is stable and has good density distribution effect. It is suitable for electrode grid line design that needs to improve transfer accuracy and stability.

[0056] Right-angle trapezoid: Suitable for photovoltaic electrode designs that require uniform grid line width and neat edges to ensure accurate current distribution.

[0057] Rectangular: A classic and common design, suitable for the transfer of standardized photovoltaic electrode grid lines, providing the largest contact area to improve current conduction efficiency.

[0058] According to an embodiment of the present invention, preferably, in S2, the aspect ratio of the mold shape is in the range of 1-3.

[0059] By setting the aspect ratio of the mold shape to a range of 1-3, the relationship between the height and width of the convex portion of the mold can be effectively adjusted, thereby optimizing the transfer effect of the electrode grid lines.

[0060] Specifically, when the aspect ratio is 1, the height and width of the mold are equal, which is suitable for electrode structures that require relatively flat gate lines and uniform thickness and width. This ensures that the electrode has good conductivity and that the conductive paste 4 can be evenly distributed during the transfer process.

[0061] In this embodiment, preferably, when the aspect ratio is close to 2, a moderate thickness and width are provided, so that the grid line has a certain height to improve the mechanical strength of the electrode, but is not too wide to maintain a fine structure. It is suitable for conventional photovoltaic electrode manufacturing and balances resistance, strength and process difficulty.

[0062] When the aspect ratio is 3, the height of the gate line is significantly greater than the width, which is suitable for more sophisticated narrow electrode designs. It can effectively reduce resistance and increase current density, but requires higher mold precision during the manufacturing process to ensure that the conductive paste 4 is fully filled in the narrow groove.

[0063] Therefore, the flexible setting of the aspect ratio range allows the geometry of the electrode grid lines to be adjusted according to different photovoltaic cell design requirements to achieve the best balance between conductivity, mechanical strength and production process.

[0064] According to an embodiment of the present invention, preferably, in S1, the surface of the mold is coated with a self-assembled monolayer.

[0065] Coating the mold surface with a self-assembled monolayer (SAM) can further improve the pattern fidelity and peelability of the polymer layer, while effectively extending the service life of the mold.

[0066] Of course, the main purpose of coating the mold surface with a self-assembled monolayer (SAM) is to improve the properties of the mold surface, including but not limited to the following: Reduce adhesion: The SAM layer can reduce the adhesion of the mold surface, making it easier for plastic or other materials to detach from the mold surface during injection molding or calendering, thereby improving production efficiency.

[0067] Controlling surface energy: The SAM layer can adjust the hydrophilicity and hydrophobicity of the mold surface, making it have better anti-adhesion performance. It can also affect the wettability of the material, which is beneficial to the material flow and molding during the production process. In our patent, the hydrophobicity of the mold is improved.

[0068] Improve corrosion resistance: The SAM layer can improve the corrosion resistance of the mold surface and extend the service life of the mold.

[0069] According to an embodiment of the present invention, preferably, the self-assembled monolayer is one of a silane compound, a siloxane compound or a perfluorinated compound.

[0070] Specifically, the silane compound may be octadecyltrichlorosilane (OTS).

[0071] The siloxane compound may be octamethylcyclotetrasiloxane (OMCTS) and octamethyl-disiloxane (OMDS), etc., which can form an organic silicon protective layer on the surface of crystalline silicon and have a certain hydrophobicity.

[0072] The perfluorinated compound may be perfluorooctylthiol (PFOT), perfluorooctyltrichlorosilane (PFOTS), 1H, 1H, 2H, 2H-perfluorodecyl-trichlorosilane, or the like.

[0073] The above materials can form a SAM layer on the mold surface by immersion, evaporation or chemical modification. In general, coating the SAM layer can improve the performance of the mold surface, improve production efficiency, extend the service life of the mold, and ensure the accuracy and quality of the imprint.

[0074] S3, coating the conductive paste 4 on the molded side of the polymer layer 2 to at least fill the groove 3 thereon, and removing the excess conductive paste 4 on the surface of the polymer layer 2, so that the surface of the groove 3 and the conductive paste 4 are located on the same plane; A good coating effect of the conductive paste 4 can be achieved, so that it is evenly distributed on the polymer layer.

[0075] According to an embodiment of the present invention, preferably, S3, coating the conductive paste 4 on the molding side of the polymer layer 2 to at least fill the groove 3 thereon, and removing excess conductive paste 4 on the surface of the polymer layer 2 so that the surface of the groove 3 and the conductive paste 4 are located on the same plane, comprising: The conductive paste is evenly applied on the polymer layer that has been embossed with high precision using a flat coating method, which can ensure that the conductive paste is tightly filled in the grooves of the polymer layer. At the same time, the excess conductive paste on the surface is scraped off to ensure that the conductive paste is completely filled and evenly distributed without deformation.

[0076] It should be noted that one of the main components of photovoltaic conductive paste is adhesive (phenolic resin, epoxy resin, etc.), whose function is to form a stable bond between the particles of the conductive paste and between the particles and the silicon wafer.

[0077] S4, providing a substrate 5, laminating the side of the polymer layer 2 having the conductive paste 4 to the substrate 5, and transferring the conductive paste 4 to the substrate 5 by a transfer method with preset process parameters; wherein the transfer process parameters are: pressure of 5-20MPa, temperature of 80-180°C, and time of 1-10min; According to an embodiment of the present invention, more preferably, S4, laminating the side of the polymer layer 2 having the conductive paste 4 to the substrate 5, comprises: At a preset temperature, by applying uniform pressure, the conductive paste 4 is tightly adhered to the surface of the substrate 5 and the conductive paste 4 is dried; and within the temperature and pressure range, the macroscopic morphology of the conductive paste 4 transferred to the substrate 5 does not change; wherein the substrate is one of a crystalline silicon wafer, glass, metal or polymer substrate.

[0078] By applying uniform pressure to the side of the polymer layer that is not coated with the conductive paste and heating and drying it, the conductive paste can be transferred to the silicon wafer due to the adhesion between the conductive paste and the silicon wafer, and the conductive paste can fit tightly to the silicon wafer, thereby ensuring a good transfer effect and further ensuring the stability of the conductive paste structure.

[0079] S5, removing the polymer layer 2, so that the conductive paste is transferred and retained on the substrate 5; According to an embodiment of the present invention, preferably, S5, removing the polymer layer 2 so that the conductive paste 4 remains on the substrate 5, comprises: The transferred silicon wafer is placed in an aqueous solution at 25-75° C. to dissolve and peel off the polymer layer, leaving the successfully transferred conductive paste pattern to form the basic structure of the photovoltaic electrode grid line 6 .

[0080] The polymer layer can be dissolved and removed, thereby completely retaining the conductive paste pattern on the silicon wafer, thereby achieving a good dissolution and separation effect.

[0081] It is important to know that the operation method is: use an electric suction cup to suck the back of the silicon wafer, suspend it in the air, immerse it in water vertically or horizontally, and stir the aqueous solution or shake the silicon wafer to dissolve and fall off the polymer layer.

[0082] The dissolution methods of the polymer layer include, but are not limited to: low-frequency ultrasonic oscillation dissolution, magnetic stirring dissolution, mechanical vibration dissolution, and static dissolution.

[0083] Of course, the water solubility of PVP can be changed by changing the molecular weight of PVP, blending modification and other methods, so that it can dissolve quickly in water.

[0084] S6, sintering the conductive paste 4 on the substrate 5 to form electrode grid lines 6 with a preset aspect ratio.

[0085] According to an embodiment of the present invention, preferably, S6, sintering the conductive paste 4 on the substrate 5 to form an electrode grid line 6 with a preset aspect ratio, comprises: The silicon wafer after the conductive paste 4 is transferred is placed in a high-temperature furnace to sinter the conductive paste 4; the sintering temperature is 500-800°C to ensure that the conductive paste is completely sintered and forms a tight connection with the silicon wafer to generate high-precision electrode grid lines 6 with a preset aspect ratio.

[0086] After the conductive paste is sintered at high temperature, it can form a conductive paste electrode grid line 6 with a desired depth and width. Preferably, the size of the conductive paste electrode grid line is 10 μm deep and 5 μm wide.

[0087] According to an embodiment of the present invention, preferably, the conductive paste 4 is one of silver paste, aluminum paste, copper paste, chromium paste, tin paste, indium paste, nickel paste, titanium paste or tantalum paste. It is understandable that the above materials all have good conductivity and can achieve the effect of multiple materials to choose from, thereby achieving the effect of flexible use, and then achieving the effect of improving market competitiveness. In the present application, more preferably, the conductive paste 4 is silver paste.

[0088] According to an embodiment of the present invention, preferably, the glass transition temperature of the polymer layer 2 is 60-120° C., and the material of the polymer layer is a water-soluble polymer material.

[0089] According to an embodiment of the present invention, preferably, the water-soluble polymer material is one of polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), polyvinyl alcohol (PVA), sodium polyacrylate (PAAS), polyvinyl alcohol-polyacrylic acid (PVA-PAA) or polyvinyl alcohol-polyacrylonitrile (PVA-PAN); Among them, the average degree of polymerization of the polyvinyl alcohol is 1700, and the degree of alcoholysis is 88-92%; the polyvinyl alcohol is ordinary polyvinyl alcohol and modified polyvinyl alcohol; the modified polyvinyl alcohol is carboxyl-modified polyvinyl alcohol, and the degree of carboxyl modification is 2-8%. It should be noted that the above materials have good solubility and biocompatibility, and can meet the use requirements of this application. In this application, more preferably, the water-soluble polymer material is polyvinyl pyrrolidone (PVP); PVP has good solubility in water, and PVP of different molecular weights can also be dissolved in a variety of organic solvents, such as ethanol, acetone, etc.; PVP can form a uniform and transparent film, and has good flexibility and adhesion; PVP is non-toxic, non-irritating, and has good biocompatibility; PVP has a certain thermal stability during processing and is suitable for a variety of thermal processing processes.

[0090] like Figure 2 As shown, according to an embodiment of the present invention, preferably, S2 further includes: a bonding layer 7 is provided on the side of the polymer layer 2 away from the mold 1, and a substrate 8 is provided on the side of the bonding layer 7 away from the polymer layer 2. It can be understood that by adopting a composite structure of the bonding layer 7 and the substrate 8, the stability, adhesion and other physical properties of the composite material can be improved, and at the same time, the polymer layer can be easily separated from the mold and protected. Preferably, the bonding layer 7 is a heat-sensitive debonding adhesive; it can achieve a good thermal separation effect, thereby facilitating the separation from the polymer layer.

[0091] According to the embodiment of the present invention, preferably, the substrate 8 is one of polyimide, polyethylene terephthalate, polyamide or polycarbonate. It is understandable that the substrate layer provides mechanical support for the entire structure and enables it to withstand stress and deformation during processing. The substrate layer can give the material specific rigidity, strength and durability; at the same time, through a variety of substrate materials to choose from, flexible selection and ease of use can be achieved, thereby improving practicality.

[0092] According to an embodiment of the present invention, preferably, S4 further includes: when the transfer is performed under preset process parameters, the adhesive layer 7 and the substrate 8 are separated from the polymer layer 2. It is understandable that during the transfer hot pressing process, due to the high temperature environment, the thermosensitive release adhesive loses its viscosity, so when the transfer is completed, the thermosensitive release adhesive will automatically fall off from the polymer layer with the substrate, thereby achieving a good automatic separation effect, thereby ensuring a smooth process. Thermosensitive release adhesive will debond when heated, that is, the adhesion between the glue and the substrate will be significantly reduced, so that it can be easily separated.

[0093] Through the structural design of the mold, the present application can obtain a polymer layer with a micron-scale groove structure, thereby controlling the size and shape of the electrode grid line and reducing the ohmic loss of the electrode grid line; the triangular prism-shaped conductive paste grid line has better conductive efficiency than the rectangular conductive paste grid line, and more light incident on the side of the triangle can be refracted into the solar panel and fully utilized; PVP, as a biodegradable and environmentally friendly material, has low environmental harm, and the PVP polymer layer that is water-soluble at room temperature can greatly reduce the demolding cost; the method has a simple process, the materials and equipment involved are economical and environmentally friendly, and the process cost is low.

[0094] The present application uses electrostatic spinning or coating and transfer processes to accurately control the size and shape of the transferred electrode grid lines, thereby reducing the ohmic loss of the electrode grid lines. The triangular prism-shaped conductive paste grid lines have better conductivity efficiency than the rectangular conductive paste grid lines, and more light incident on the sides of the triangle can be refracted into the solar panel and fully utilized. PVP, as a biodegradable and environmentally friendly material, has low environmental harm. The PVP coating, which is water-soluble at room temperature, can greatly reduce the cost of demolding. The method is simple in process, the materials and equipment involved are economical and environmentally friendly, and the process cost is low.

[0095] This application also has the following beneficial effects: 1. Improving the adhesion of the transferred conductive paste: By using polyvinyl pyrrolidone (PVP) as an ideal carrier, the present invention achieves stronger adhesion between the conductive paste and the substrate; the water solubility and biocompatibility of the PVP coating enable the conductive paste to fill the groove more tightly during the transfer process, thereby ensuring a firm fit between the conductive paste and the substrate.

[0096] Specifically, a suitable carrier material is selected: PVP, as a water-soluble, biocompatible and film-forming polymer compound, has good adhesion and can serve as an ideal carrier for transferring conductive paste to ensure a firm fit between the conductive paste and the substrate.

[0097] 2. Improve the accuracy and stability of electrode patterns: Prepare PVP fiber films with micron-scale or even nano-scale electrode patterns through electrospinning, simplify the process of hot stamping, and do not need to prepare polymer layers separately. The present invention achieves high accuracy and stability of electrode patterns, which helps to improve the performance and efficiency of photovoltaic cells.

[0098] 3. Simplify the production process: The conductive slurry is applied on the PVP coating after hot pressing by a flat coating method, and then transferred onto the substrate. The present invention simplifies the production process, reduces production costs and time, and improves production efficiency.

[0099] Specifically, the conductive slurry is applied by a flat coating method and transferred onto a silicon wafer. The PVP film is then washed with water at an appropriate temperature to dissolve it and fall off, ultimately forming a micron-scale electrode grid line with a depth of 10 μm and a width of 5 μm, thus achieving successful transfer and sintering of the conductive slurry.

[0100] From the above description, it can be seen that the present application achieves the following technical effects: In an embodiment of the present application, a method of directly preparing a polymer layer on a mold and transferring to prepare photovoltaic electrode grid lines is adopted, wherein S1, a mold with a preset shape complementary to the electrode pattern to be embossed is provided; S2, a desired polymer layer is prepared on the mold according to preset process parameters, and used as a transfer substrate; S3, a conductive paste is applied on the forming side of the polymer layer to at least fill the groove thereon, and excess conductive paste on the surface of the polymer layer is removed so that the groove and the surface of the conductive paste are located on the same plane; S4, a substrate is provided, the side of the polymer layer having the conductive paste is bonded to the substrate, and the conductive paste is transferred to the substrate by a transfer method with preset process parameters; wherein the process parameters of the transfer are: pressure of 5-20MPa, temperature of 80-180°C and time of 1-10min; S5, the polymer layer is removed so that the conductive paste remains on the substrate; S6, the conductive paste is sintered The electrode grid lines are formed on the substrate with a preset aspect ratio, thereby achieving the purpose of obtaining the required polymer layer and preparing the photovoltaic electrode grid lines, thereby realizing the technical effects of saving process time, simplifying the process flow, improving the service life of the mold, and ensuring that the base film has good flexibility and is easy to detach. This solves the problem that in the transfer technology, the transfer base film cannot meet the use requirements due to its flexibility, so that some base films are too soft, resulting in deformation after the subsequent conductive slurry is filled in; some base films cannot be used normally due to being too hard and brittle; the subsequent substrate cannot be automatically separated from the substrate, thereby affecting the grid line structure; and, in the current process of making the polymer layer into high-resolution photovoltaic electrode grid lines through high-precision hot embossing and transfer, due to the high aspect ratio requirement and the narrow distance between the grid lines, repeated embossing and tearing with large pressure will cause damage to the mold, thereby shortening the service life of the mold.

[0101] The use of transfer conductive paste technology has the following advantages over screen printing: 1. Higher resolution: Transfer conductive paste technology is generally able to achieve higher resolution because the conductive paste can be accurately transferred on a smaller scale, thereby achieving finer patterns and lines.

[0102] 2. The quality of the finished product is more stable: Since the transfer conductive paste technology can be carried out in a controlled environment, a more stable and consistent finished product quality can be obtained, avoiding problems such as uneven ink flow that may occur in screen printing.

[0103] 3. Higher production efficiency: Transfer conductive paste technology can usually achieve automated production, improve production efficiency, reduce manual operations, and save time and costs.

[0104] 4. Wider applicability: Transfer conductive paste technology can be applied to various substrates and materials, including flexible substrates and non-flat surfaces, and has a wider range of applicability.

[0105] 5. Better durability: Transfer conductive paste technology can usually achieve better adhesion and durability, making the printed pattern more durable and stable, and less susceptible to external environmental influences.

[0106] like Figure 4 As shown, the present application also relates to a method for preparing a polymer layer, comprising the following steps: Step 1, dissolving PVP in a preset solvent to prepare a uniform spinning solution; A uniform spinning solution can be obtained by solution preparation.

[0107] According to an embodiment of the present invention, preferably, in step 1, PVP is dissolved in a preset solvent to prepare a uniform spinning solution, for example: PVP and tetrabutyl titanate are dissolved in a mixed solvent of ethanol and acetic acid to prepare a precursor solution with mass fractions of 3-5% PVP and 18-22% tetrabutyl titanate, respectively.

[0108] According to an embodiment of the present invention, more preferably, PVP and tetrabutyl titanate are dissolved in a mixed solvent of ethanol and acetic acid to prepare a precursor solution with mass fractions of 4% PVP and 20% tetrabutyl titanate, respectively.

[0109] According to an embodiment of the present invention, preferably, step 1, dissolving PVP in a preset solvent to prepare a uniform spinning solution, further comprises: PVP and diphenylalanine were slowly added to a mixed solvent of methanol and N,N-methylacetamide under stirring, and stirring was continued until they were completely dissolved to obtain a transparent polymer solution.

[0110] Specifically, in order to obtain a suitable polymer layer, it is first necessary to prepare a uniform spinning solution. The key to this process is to select appropriate solvents and precursors to ensure that the spinning solution has suitable viscosity and uniformity, which is conducive to electrospinning to form stable fibers.

[0111] Of course, the present application provides a variety of solution preparation schemes, which can be selected according to actual needs, thereby achieving flexible use effects.

[0112] Step 2: placing the spinning solution in a syringe and spinning through an electrospinning device; According to an embodiment of the present invention, preferably, step 2, placing the spinning solution in a syringe and spinning through an electrospinning device, comprises: The prepared spinning solution is placed in a syringe with a preset inner diameter, and electrospinning is performed using a preset working voltage intensity.

[0113] During the spinning process, temperature and humidity are controlled to prevent fiber breakage or excessive stretching, ensuring fiber stability, thickness uniformity, and morphology consistency.

[0114] Of course, the specific parameter settings can be set according to actual usage requirements and are not limited in this application.

[0115] Step 3: During the spinning process, the fiber will form a film on the mold and the fiber film will be collected.

[0116] Specifically, the polymer layer formed by spinning needs to be uniformly deposited on a collecting device; the subsequent processing steps may vary depending on the final use of the fiber film.

[0117] Through the above steps, a suitable polymer layer can be prepared, and the molecular structure of the polymer layer is: Those skilled in the art should be aware of this molecular structure.

[0118] The polymer layer prepared by the polymer layer preparation method of the present application has a certain flexibility and is not too brittle; at the same time, the base film is not too soft, which can prevent the conductive paste from deforming after being filled in; and it can also be dissolved in water and automatically detach from the silicon wafer, leaving the conductive paste unaffected.

[0119] The glass transition temperature of the polymer layer is 60℃-120℃, so the inherent properties of PVP ensure that there is no rebound and shape change after hot pressing.

[0120] From the above description, it can be seen that the present application achieves the following technical effects: In the embodiment of the present application, the polymer layer is prepared by electrospinning. Step 1: PVP is dissolved in a preset solvent to prepare a uniform spinning solution; Step 2: The spinning solution is placed in a syringe and spun by an electrospinning device; Step 3: During the spinning process, the fiber will form a film on the mold, and the collected fiber film will be post-processed to finally obtain the required polymer layer, thereby achieving the technical effect that the base film has good flexibility and is easy to detach, thereby solving the problem that in the transfer technology, the transfer base film cannot meet the use requirements due to its flexibility, so that some base films are too soft, resulting in deformation after the subsequent conductive slurry is filled in; some base films are too hard, resulting in too brittle to be used normally; and the subsequent base cannot be automatically separated from the substrate, thereby affecting the grid line structure. Electrospinning the polymer layer directly on the mold can replicate the depth of the groove to achieve very high precision, and at the same time can avoid repeated stamping of the mold and extend its service life.

[0121] The specific examples are further described below: Example 1 1. Solution preparation: PVP and tetrabutyl titanate are dissolved in a mixed solvent of ethanol and acetic acid to prepare a precursor solution with a mass fraction of 4% PVP and 20% tetrabutyl titanate respectively; 2. Provide a mold, and perform electrospinning on the mold: use a working voltage of 1.8 kV / cm, an inner diameter of a syringe of 0.43 mm, a flow rate of a spinning solution of 0.5 mL / h, a temperature of 25° C., and a humidity of 45%, and spin directly form a polymer layer with a thickness of 50 μm and an electrode pattern on the mold; 3. Conductive slurry coating and transfer: Use the flat coating method to evenly apply the conductive slurry on the surface of the PVP film, scrape off the excess conductive slurry, and then transfer it to the surface of the silicon wafer; 4. PVP removal: Wash in 60℃ water for 3 minutes to completely dissolve and remove the polymer layer; 5. Conductive paste sintering: The transferred silicon wafer is sintered at 700°C for half a minute to form a conductive paste electrode grid line.

[0122] At this time, the test results of the photovoltaic electrode grid line transfer method are: the depth of the conductive paste electrode grid line is 10μm, the width is 5μm, the conductive paste is tightly combined with the silicon wafer, and the conductivity is excellent, which is suitable for the application of high-efficiency photovoltaic cells.

[0123] Example 2 The difference between Example 2 and Example 1 is that: 1. Solution preparation: PVP and diphenylalanine are dissolved in a mixed solvent of methanol and N, N-methylacetamide at a mass fraction of 4% and 10%, respectively, to form a uniform polymer solution; 2. providing a mold, and performing electrospinning on the mold: using the same electrospinning conditions, spinning to form a polymer layer with a thickness of 65 μm; 3. Conductive slurry coating and transfer: The conductive slurry is coated and transferred in the same way; 4. PVP removal: Wash in 70℃ water for 7 minutes to dissolve and remove PVP; 5. Conductive paste sintering: sinter at 800°C for half a minute.

[0124] At this time, the test results of the photovoltaic electrode grid line transfer method are: the depth of the conductive paste electrode grid line is 9 μm, the width is 6 μm, and the conductive paste transfer quality is good.

[0125] Example 3 The difference between Example 3 and Example 1 is that: 1. Solution preparation: the same PVP and tetrabutyl titanate solution as in Example 1 is used; 2. providing a mold, and performing electrospinning on the mold: increasing the spinning solution flow rate to 1 mL / h to form a polymer layer with a thickness of 85 μm; 3. Conductive slurry coating and transfer: The conductive slurry is coated and transferred in the same way; 4. PVP removal: Wash in 55°C water for 8 minutes to dissolve and remove PVP; 5. Conductive paste sintering: sinter at 700°C for 1 minute.

[0126] At this time, the test results of the photovoltaic electrode grid line transfer method are: the depth of the conductive paste electrode grid line is 12μm, the width is 7μm, and the conductivity is equivalent to the previous embodiment, but due to the thick polymer layer, the conductive paste transfer is uneven in some areas, resulting in a slight decrease in conductivity.

[0127] Example 4 The difference between Example 4 and Example 1 is that the traditional PVP coating process is adopted.

[0128] 1. PVP coating: The PVP solution is directly applied to the mold using the traditional coating method with a thickness of 25 μm.

[0129] At this time, the test results of the photovoltaic electrode grid line transfer method are: the depth of the conductive paste electrode grid line is 12 μm, the width is 6 μm, and the conductivity is equivalent to that of the above-mentioned embodiment.

[0130] Example 5 The difference between Example 5 and Example 1 is that PEG is used as the base material.

[0131] At this time, the test results of the photovoltaic electrode grid line transfer method are: the depth of the conductive paste electrode grid line is 11 μm, the width is 6 μm, and the conductivity is equivalent to that of the above-mentioned embodiment.

[0132] Example 6 The difference between Example 6 and Example 4 is that PVA is used as the base material and is coated on the mold by a flat plate coating method.

[0133] At this time, the test results of the photovoltaic electrode grid line transfer method are: the depth of the conductive paste electrode grid line is 11 μm, the width is 6 μm, and the conductivity is equivalent to that of the above-mentioned embodiment.

[0134] From the above test results we can see that: Examples 1-6 can all achieve high-precision conductive paste electrode grid lines with good conductivity and low contact resistance, and Example 1 in particular exhibits the best performance. This solution improves photoelectric conversion efficiency and reduces industrialization costs.

[0135] The present application also relates to a photovoltaic cell, including the photovoltaic electrode grid line prepared as above. The photovoltaic electrode grid line prepared in this embodiment can be applied to photovoltaic cells, and its basic principle and technical effects are the same as those in the above embodiment. For parts not mentioned in this embodiment, please refer to the above corresponding content.

[0136] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical scheme of the present invention, and these equivalent transformations all belong to the protection scope of the present invention.

Claims

1. A method for preparing a photovoltaic electrode grid line, characterized in that: The following steps are involved: S1, providing a mold with a preset shape complementary to the electrode pattern to be embossed; S2, preparing a desired polymer layer on the mold according to preset process parameters, and using the polymer layer as a transfer substrate; S3, coating the conductive paste on the molding side of the polymer layer to at least fill the groove thereon, and removing excess conductive paste on the surface of the polymer layer so that the groove and the surface of the conductive paste are located on the same plane; S4, providing a substrate, laminating the side of the polymer layer having the conductive paste to the substrate, and transferring the conductive paste to the substrate by a transfer method with preset process parameters; wherein the transfer process parameters are: pressure of 5-20 MPa, temperature of 80-180° C., and time of 1-10 min; S5, removing the polymer layer so that the conductive paste remains on the substrate; S6. Sintering the conductive paste on the substrate to form electrode grid lines with a preset aspect ratio.

2. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: S2, preparing a desired polymer layer on the mold according to preset process parameters and using it as a transfer substrate, comprising: A polymer layer with a thickness of 15-85 μm and grooves is prepared on the mold, and after drying at 100-125° C., it is demoulded from the mold side to obtain a polymer layer with the desired micrometer-scale or nanometer-scale electrode pattern as a transfer substrate.

3. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: In S2, the thickness of the polymer layer is 15-50 μm.

4. The method for preparing photovoltaic electrode grid lines according to claim 2, characterized in that: In S2, the polymer layer is prepared by electrospinning or flat coating.

5. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: In S1, the mold is one of a single crystal silicon substrate, a polycrystalline silicon substrate, a copper substrate, a nickel substrate, a copper-nickel alloy substrate, a nickel-iron alloy substrate, an iron-aluminum alloy substrate or an aluminum alloy substrate.

6. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: In S1, the convex portion of the mold is complementary in shape to the concave portion; Wherein, the shape of the mold is one of an isosceles triangle, an isosceles trapezoid, an ellipse, a hexagon, a right-angled trapezoid or a rectangle.

7. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: In S1, the aspect ratio of the mold shape ranges from 1 to 3.

8. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: In S1, the surface of the mold is coated with a self-assembled monolayer.

9. The method for preparing photovoltaic electrode grid lines according to claim 8, characterized in that: The self-assembled monomolecular layer is one of silane compounds, siloxane compounds or perfluorinated compounds.

10. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: S3, coating the conductive paste on the molding side of the polymer layer to fill the groove thereon, and removing the excess conductive paste on the surface of the polymer layer so that the groove and the surface of the conductive paste are located on the same plane, including: The conductive paste is evenly applied on the formed polymer layer by a flat coating method so that the conductive paste completely fills the groove, and the excess conductive paste is scraped off to ensure that the conductive paste is completely filled and evenly distributed without deformation.

11. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: S4, providing a substrate, and laminating the side of the polymer layer having the conductive paste to the substrate, comprising: At a preset temperature, by applying isotropic pressure, the conductive paste is tightly attached to the surface of the substrate while drying the conductive paste; and within the temperature and pressure range, the macroscopic morphology of the conductive paste transferred to the substrate does not change; Wherein, the substrate is one of crystalline silicon wafer, glass, perovskite, metal or polymer substrate.

12. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: S5. Removing the polymer layer so that the conductive paste remains on the substrate, comprising: The transferred silicon wafer is placed in an aqueous solution at 25-75°C to dissolve and peel off the polymer layer, leaving behind the successfully transferred conductive paste pattern to form the basic structure of the photovoltaic electrode grid line.

13. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: S6, sintering the conductive paste on the substrate to form an electrode grid line with a preset aspect ratio, including: The silicon wafer after the conductive paste is transferred is placed in a high-temperature furnace to sinter the conductive paste; the sintering temperature is 500-800℃, ensuring that the conductive paste is completely sintered and forms a tight connection with the silicon wafer to generate electrode grid lines with a preset aspect ratio.

14. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: The conductive paste is one of silver paste, aluminum paste, copper paste, chromium paste, tin paste, indium paste, nickel paste, titanium paste or tantalum paste.

15. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: The glass transition temperature of the polymer layer is 60-120° C., and the material of the polymer layer is a water-soluble polymer material.

16. The method for preparing photovoltaic electrode grid lines according to claim 15, characterized in that: The water-soluble polymer material is one of polyvinyl pyrrolidone, polyethylene glycol, polyvinyl alcohol, sodium polyacrylate, polyvinyl alcohol-polyacrylic acid or polyvinyl alcohol-polyacrylonitrile; The average polymerization degree of the polyvinyl alcohol is 1700, and the alcoholysis degree is 88-92%; the polyvinyl alcohol is ordinary polyvinyl alcohol and modified polyvinyl alcohol; the modified polyvinyl alcohol is carboxyl-modified polyvinyl alcohol, and the carboxyl modification degree is 2-8%.

17. The method for preparing photovoltaic electrode grid lines according to claim 1, characterized in that: S2 further includes: a bonding layer is disposed on a side of the polymer layer away from the mold, and a substrate is disposed on a side of the bonding layer away from the polymer layer.

18. The method for preparing photovoltaic electrode grid lines according to claim 17, characterized in that: The substrate is one of polyimide, polyethylene terephthalate, polyamide or polycarbonate.

19. The method for preparing photovoltaic electrode grid lines according to claim 17, characterized in that: S4 further includes: when the transfer is performed under preset process parameters, the adhesive layer and the substrate are separated from the polymer layer.

20. A photovoltaic cell, characterized in that The invention comprises a photovoltaic electrode grid line prepared by the preparation method according to any one of claims 1 to 19.

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