A method for manufacturing a solar cell and a solar cell manufacturing apparatus

Abstract

The application discloses a solar cell preparation method and a solar cell production device. The preparation method comprises the following steps: providing at least one cell piece; arranging a flexible mold on a surface to be printed of each cell piece, wherein a plurality of first grid line openings are arranged on the flexible mold; performing grid line printing on the cell piece provided with the flexible mold through a printing plate to obtain an intermediate cell piece, wherein a plurality of second grid line openings are arranged on the printing plate, the first grid line openings and the second grid line openings are in one-to-one correspondence, and paste flowing out of the second grid line openings fills the first grid line openings; performing drying treatment on the intermediate cell piece; and removing the flexible mold to obtain the solar cell.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, specifically to a method for preparing a solar cell and solar cell production equipment. Background Technology

[0002] Currently, in order to improve the photoelectric conversion efficiency of solar cells, grid line design is becoming increasingly refined to reduce the shading area and lower the series resistance.

[0003] However, in the actual grid line printing process, the actual grid line size often deviates from the design value, affecting battery performance.

[0004] Therefore, providing a method for fabricating solar cells, and improving grid line size accuracy and cell performance are urgent problems to be solved in this field. Summary of the Invention

[0005] This invention aims to address, to a certain extent, one of the technical problems in related technologies. To this end, this invention provides a method for preparing a solar cell and equipment for producing a solar cell.

[0006] As a first aspect of this application, the present invention discloses a method for preparing a solar cell, the method comprising:

[0007] Provide at least one battery cell;

[0008] A flexible mold is set on the printing surface of each battery cell, wherein the flexible mold has a plurality of through first grid line openings;

[0009] A battery cell with a flexible mold is printed with grid lines using a printing plate to obtain an intermediate battery cell. The printing plate is provided with a plurality of second grid line openings, and the first grid line openings correspond one-to-one with the second grid line openings, so that the paste flowing out from the second grid line openings fills the first grid line openings.

[0010] The intermediate battery cell is dried.

[0011] Remove the flexible mold to obtain the solar cell.

[0012] Furthermore, the step of setting a flexible mold on the surface of the battery cell to be printed includes:

[0013] A flexible film is placed on the surface of the battery cell to be printed with a set tension;

[0014] The flexible film is patterned to obtain the flexible mold.

[0015] Furthermore, the flexible mold includes a photosensitive film, and the patterning process of the flexible film includes:

[0016] The photosensitive film is patterned using photolithography to obtain a flexible mold.

[0017] Further, the flexible film is applied to the printing surface of the battery cell at a set tension, including:

[0018] The flexible film is unwound by an unwinding mechanism and wound up by a winding mechanism, and then transmitted to the top of the battery cell at the set tension.

[0019] A pressing mechanism is used to bond the flexible film and the battery cell together. The pressing mechanism includes a first pressing roller and a second pressing roller arranged opposite to each other. The first pressing roller is located at the bottom of the battery cell, and the second pressing roller is located at the top of the flexible film. The flexible film and the battery cell are bonded together by roll pressing using the first pressing roller and the second pressing roller.

[0020] Further, removing the flexible mold includes:

[0021] The winding mechanism is used to wind up the flexible mold between the unwinding mechanism and the winding mechanism, so that the flexible mold is pulled away from the intermediate battery cell.

[0022] Furthermore, the step of printing grid lines on the battery cell with the flexible mold using a printing plate includes:

[0023] Identify the position information of the battery cell;

[0024] Based on the position information, the printing plate and the flexible mold are aligned so that the second grid line opening is opposite to the first grid line opening, and there is a set interval between the printing plate and the flexible mold;

[0025] The printing plate is coated with a scraping agent, wherein the scraping direction is consistent with the length direction of the second grid line opening.

[0026] Furthermore, the coating pressure is in the range of 20N to 80N.

[0027] Furthermore, the spacing between the printed circuit board and the flexible mold is between 0.1 mm and 1 mm, the thickness of the flexible mold is between 5 micrometers and 15 micrometers, and the width of the first gate opening is between 5 micrometers and 50 micrometers.

[0028] As a second aspect of this application, this application discloses a solar cell production equipment, comprising: a transport platform, a flexible mold, an auxiliary mechanism, a printing mechanism, a drying mechanism, and a film removal mechanism. The transport platform is used to transport solar cells. The auxiliary mechanism, printing mechanism, drying mechanism, and film removal mechanism are arranged sequentially along the transport direction of the transport platform. The auxiliary mechanism is used to place the flexible mold on the surface of the solar cell to be printed. The flexible mold has multiple through-holes for first grid lines. The printing mechanism includes a printing plate with multiple through-holes for second grid lines. The printing mechanism is used to print grid lines on the solar cell with the flexible mold, such that the first grid lines correspond one-to-one with the second grid lines. The drying mechanism is used to dry the solar cell. The film removal mechanism is used to remove the flexible mold from the solar cell.

[0029] Furthermore, the auxiliary mechanism includes a winding mechanism, an unwinding mechanism, and a pressing mechanism. The winding mechanism and the unwinding mechanism are arranged opposite to each other along the transmission direction. The unwinding mechanism is used to unwind the flexible film, and the winding mechanism is used to wind the flexible film. The flexible film can be transmitted to the top of the solar cell with a set tension through the unwinding mechanism and the winding mechanism. The pressing mechanism includes a first pressing roller and a second pressing roller arranged opposite to each other. The first pressing roller is located at the bottom of the solar cell, and the second pressing roller is located at the top of the flexible film. The flexible film and the solar cell can be rolled together by the first pressing roller and the second pressing roller.

[0030] The solar cell fabrication method provided by this invention involves pre-setting a flexible mold with a first grid line opening on the surface of the solar cell to be printed, and precisely aligning it with a second grid line opening on the printing plate. This ensures that after the ink is scraped through the printing plate, it can only enter and fill the first grid line opening of the flexible mold. The first grid line opening precisely limits and shapes the ink, effectively restricting its lateral diffusion during the printing process. This method significantly suppresses defects common in traditional screen printing, such as linewidth widening, blurred edges, and broken grids, achieving stable forming of high-precision, narrow-linewidth sub-grids and improving the resolution and consistency of the grid line pattern. Furthermore, the flexible mold can be completely peeled off after drying without affecting the already formed grid line structure, and it requires no major modifications to existing screen printing equipment, exhibiting strong process compatibility and ease of operation. In addition, this solution improves ink utilization, reduces silver paste waste, helps reduce material costs, and improves the photoelectric conversion efficiency and mass production yield of solar cells.

[0031] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and accompanying drawings. The preferred embodiments or means of the present invention will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. In addition, each of these features, elements and components appearing in the following text and drawings is a plurality of, and different symbols or numbers are used for convenience of representation, but all represent parts with the same or similar construction or function. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings:

[0033] Figure 1 This is a flowchart of one embodiment of the solar cell fabrication method provided by the present invention;

[0034] Figure 2 This is a schematic flowchart of one embodiment of the solar cell fabrication method provided by the present invention;

[0035] Figure 3(a) is a schematic flowchart of one embodiment of the solar cell fabrication method provided by the present invention;

[0036] Figure 3(b) is a schematic flowchart of one embodiment of the solar cell fabrication method provided by the present invention;

[0037] Figure 4 This is a schematic flowchart of one embodiment of the solar cell fabrication method provided by the present invention;

[0038] Figure 5 This is a schematic diagram of one embodiment of the flexible mold provided by the present invention;

[0039] Figure 6 This is a schematic diagram of one embodiment of the solar cell grid line printing method provided by the present invention;

[0040] Figure 7 This is a scanned image of the grid line morphology of a solar cell provided in Embodiment 1 of the present invention;

[0041] Figure 8 This is a scanning image of the grid line morphology of a solar cell provided in the comparative example of this invention.

[0042] Figure Labels

[0043] 1: Solar cell production equipment; 2: Flexible thin film; 3: Solar cell; 10a: Unwinding mechanism; 10b: Rewinding mechanism; 11a: First pressure roller; 11b: Second pressure roller; 12: Patterning mechanism; 13: Printing mechanism; 14: Drying mechanism; 16: Film removal mechanism; 15: Transfer platform; 120: Laser etching mechanism; 121: Exposure mechanism; 122: Developing mechanism; 123: Developing and drying mechanism; 17: Applying pressure head; 170: Pressure head platform; 130: Printing plate; 131: Outer frame; 1301: Second grid line opening; 20: Flexible mold; 201: First grid line opening; 132: Squeegee; 133: Metal paste. Detailed Implementation

[0044] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described are intended to explain the present invention and should not be construed as limiting the invention.

[0045] The terms "an embodiment," "example," or "example" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this application. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0046] With the widespread application of solar cells in the global new energy field, improving their photoelectric conversion efficiency and reducing manufacturing costs have become the focus of industry attention. In the manufacturing process of solar cells, the optimization of the electrode structure has a significant impact on overall performance. Currently, the mainstream electrode preparation method uses screen printing technology to print conductive paste onto the surface of the cell to form grid lines. This method has advantages such as mature technology, relatively low cost, and suitability for large-scale production, and is therefore widely used in the manufacture of crystalline silicon solar cells.

[0047] To improve the photoelectric conversion efficiency of solar cells, grid line designs are becoming increasingly finer to reduce shading area and lower series resistance. However, traditional screen printing technology has certain limitations in fabricating fine grid line structures. Firstly, while grid line designs are becoming increasingly finer to reduce shading area and lower series resistance, the printing accuracy of fine grid lines is affected by factors such as screen opening size, ink flowability, and squeegee pressure. This can easily lead to problems such as increased line width and blurred edges, causing the actual grid line size to deviate from the design value and affecting cell performance.

[0048] To overcome these problems, researchers and companies have explored various novel grid structures and their fabrication methods in recent years. For example, the industry has attempted to use laser 3D printing to fabricate sub-grids for solar cells. This method involves using a first laser to create grooves in the passivation layer of the solar cell, a nozzle delivering metal powder above the grooves, and a second laser instantly thermally melting and sintering the metal powder onto the solar cell to form a metal electrode. This method can precisely fabricate sub-grid electrodes and offers advantages such as a high aspect ratio, reduced shading, improved efficiency, lower costs, and environmental friendliness. However, laser equipment is expensive and requires strict operational precision, placing high demands on the skill level of technicians and the stability of the equipment.

[0049] The inventors of this application have discovered the following drawbacks in the relevant technologies: First, linewidth control is difficult, and widening is a serious problem. In traditional screen printing, the mesh openings lack a physical structure to constrain the flow of the ink. Under the pressure of the squeegee, the ink easily spreads laterally, causing the actual linewidth to exceed the design value, increasing the light-blocking area and reducing photoelectric conversion efficiency. Second, printing accuracy is limited, defects are frequent, and stability is poor. Poor ink permeability, unreasonable screen pattern design, and difficulty in controlling process parameters in screen printing can lead to defects such as broken grids and incomplete printing. In addition, screen printing is extremely sensitive to parameters such as squeegee speed, pressure, and screen distance, resulting in a narrow process window, poor production stability, and problems such as uneven printing and poor batch consistency. Third, material costs are high and resource utilization is low. Fine grid printing usually requires the use of high-mesh screens and high-performance conductive silver paste, leading to a significant increase in material costs. Meanwhile, the low screen opening ratio limits the effective permeability of the slurry, resulting in slurry waste; the screen is easily damaged and needs to be replaced frequently, which further increases maintenance costs and resource consumption, and reduces overall production efficiency.

[0050] Based on the above problems, this application aims to effectively restrict the lateral flow of the slurry through structural design, reduce widening, and improve the resolution and edge clarity of the printed sub-grids to meet the electrode requirements of high-performance batteries; secondly, it aims to improve process controllability and yield without significantly changing the existing production line.

[0051] As the first aspect of this application, the present invention discloses a method for preparing a solar cell, such as... Figures 1 to 6 As shown, the preparation method includes:

[0052] S100, providing at least one battery cell 3;

[0053] S200. A flexible mold 20 is provided on the printing surface of each battery cell 3, wherein the flexible mold 20 has a plurality of through first grid line openings 201.

[0054] S300: The battery cell 3 with the flexible mold 20 is printed with grid lines through the printing plate 130 to obtain an intermediate battery cell. The printing plate 130 is provided with a plurality of second grid line openings 1301. The first grid line openings 201 and the second grid line openings 1301 correspond one-to-one, so that the paste flowing out from the second grid line openings 1301 fills the first grid line openings 201.

[0055] S400, Drying the intermediate battery cells;

[0056] S500: Remove the flexible mold 20 to obtain the solar cell.

[0057] The purpose of this invention is to provide a novel auxiliary printing method for a flexible mold 20. For example... Figure 2 and Figure 6 As shown, this method involves laying a flexible mold 20 before printing, and scraping a metal paste 133 onto the printing plate 130 with a squeegee 132. The metal paste 133 flows out from the second grid opening 1301 and falls onto the flexible mold 20 to fill the first grid opening 201. The flexible mold 20 of this application can guide the metal paste 133 to be deposited along a designed path and can be removed after printing. This significantly improves the printing accuracy of the sub-grid lines, reduces broadening and defects, optimizes the paste permeability and screen life, expands the printing process window, and reduces silver paste waste and production costs without increasing process complexity. This comprehensively improves the electrical performance and manufacturing efficiency of solar cells.

[0058] In step S100, this application does not specifically limit the type of solar cell 3, as long as it is a solar cell with no grid electrodes on one or both sides. For example, solar cell 3 can be a tunnel oxide passivated contact (TOPCon) cell, an intrinsic thin-film heterojunction (HJT) cell, or an emitter and back passivated cell (PERC). It is not limited to crystalline silicon cells; it can also be other types of cells or tandem cells using the above-mentioned cells, such as perovskite tandem cells. This invention does not specifically limit the method of obtaining the semiconductor substrate; for example, it can be obtained by purchasing it externally. Another example is that it can be obtained through a fabrication method.

[0059] In step S200, this application does not specifically limit how the flexible mold 20 is set on the surface of the battery cell 3 to be printed. For example, a vacuum adsorption bonding method can be used to cover the flexible mold 20 with the first grid line opening 201 on top of the battery cell 3, and a vacuum can be drawn at the bottom of the battery cell 3 so that the flexible mold 20 is tightly attached to the surface of the battery cell 3 under vacuum. Another example is that a removable adhesive layer can be applied to the non-opening area on the back of the flexible mold 20 by adhesive bonding, and the mold can be attached to the surface of the battery cell 3 by rollers or a robotic arm. As an optional implementation, in some embodiments, the step of setting the flexible mold 20 on the surface of the battery cell 3 to be printed includes:

[0060] The flexible film 2 is placed on the printing surface of the battery cell 3 with a set tension;

[0061] The flexible film 2 is patterned to obtain the flexible mold 20.

[0062] The preferred solution of this application is not a simple attachment, but rather an active application and control of tension to keep the flexible mold 20 flat, stable, and wrinkle-free during the printing process. This tension setting eliminates any looseness, warping, or micro-wrinkles in the flexible mold 20 during attachment, ensuring a tight and flat fit with the surface of the battery cell 3. This results in a stable and consistent gap between the printing plate 130 and the mold. Simultaneously, the edge sealing of the grid openings is improved, effectively preventing conductive paste from laterally seeping into non-target areas from the slit sidewalls. Furthermore, the mold under tension has a more stable linewidth, clearer graphic boundaries, and is less prone to deformation. This also ensures that the flexible mold 20 experiences uniform force during subsequent demolding, resulting in a smooth peeling process and reducing the likelihood of pulling on the formed grid lines. Preferably, the tension is set within the range of 1 N / cm to 10 N / cm.

[0063] This application does not impose any special limitations on the patterning process of the flexible film 2, as long as the pattern with grid line accuracy is formed on the flexible film 2. Furthermore, the order of the patterning process is not limited; it can be performed before or after the flexible film 2 is bonded to the battery cell 3. To improve the accuracy of the patterning, it is preferable to perform the patterning process after the flexible film 2 is placed on the printing surface of the battery cell 3.

[0064] This application does not impose any special limitations on the material of the flexible film 2. Preferably, the flexible film 2 includes polyethylene terephthalate (PET), polyimide (PI), or other photosensitive films. These materials, as flexible film 2, are low-cost, highly transparent, and easy to pattern. Furthermore, mature and compatible roll-to-roll and unrolling equipment are already available, making them suitable for mass production. They also have a lower coefficient of thermal expansion during subsequent drying, curing, or other high-temperature environments, reducing the likelihood of mold deformation and ensuring the accuracy of the grid lines, making them suitable for printing with finer linewidths. On the other hand, these materials have low surface energy and weak adhesion to conductive pastes such as silver paste, which facilitates complete peeling after printing without damaging the formed grid lines.

[0065] The patterning process in this application can be selected based on the specific flexible film 2 material. In some embodiments, the flexible mold 20 includes a photosensitive film, and the patterning process of the flexible film 2 includes: performing photolithography on the photosensitive film to obtain the flexible mold 20.

[0066] like Figure 2 As shown in Figures 3(a) and 3(b), this application does not specifically limit the patterning mechanism 12. In some embodiments, the patterning process of the flexible film 2 includes any one of the following methods: laser etching, photolithography, or molding. If the laser patterning method is selected, as shown in Figure 3(a), the flexible film 2 is preferably an organic film material with a thickness between 5 micrometers and 15 micrometers. The laser etching mechanism 120 selects a femtosecond or picosecond laser in the ultraviolet band, with a spot size of less than 10 micrometers. The laser etching mechanism 120 positions the solar cell 3 by locating the edge or by locating the mark points on the solar cell 3. If the photolithography patterning method is selected, as shown in Figure 3(b), the flexible film 2 is made of a photosensitive film material. The flexible film 2 is first exposed by the exposure mechanism 121, then developed by the developing mechanism 122, and finally cured by the developing and drying mechanism 123 to form a pattern.

[0067] This application does not impose specific limitations on how the initial flexible film 2 is set at a set tension on the printing surface of the battery cell 3. For example, it can be achieved by mechanical clamping and re-tensioning; or, for example, the flexible film 2 can be pre-tensioned and fixed to a metal or plastic frame, and the entire film frame can be pressed down onto the surface of the battery cell 3; or, for example, the flexible film 2 material can be formed into a continuously driven roll at a constant tension through unwinding and rewinding using a roll-to-roll method, and during the conveying process, the film is continuously peeled from the roll and adhered to the surface of the battery cell 3 by pressure rollers. In some specific embodiments, such as Figures 2 to 4 As shown, the step of setting the initial flexible film 2 at a set tension on the printing surface of the battery cell 3 includes:

[0068] The flexible film 2 is unwound by the unwinding mechanism 10a and wound by the winding mechanism 10b to set the tension and transmit it to the top of the battery cell 3.

[0069] A pressing mechanism is used to bond the flexible film 2 and the battery cell 3. The pressing mechanism includes a first pressing roller 11a and a second pressing roller 11b arranged opposite to each other. The first pressing roller 11a is located at the bottom of the battery cell 3, and the second pressing roller 11b is located at the top of the flexible film 2. The flexible film 2 and the battery cell 3 are bonded together by rolling through the first pressing roller 11a and the second pressing roller 11b.

[0070] In other embodiments, the pressing mechanism described above may not be used for pressing, such as... Figure 4 As shown, a dedicated applicator 17 and a presser platform 170 can be used to press the flexible film 2 and the battery cell 3 together, and the cross-sectional area of ​​the presser is matched with that of the battery cell 3.

[0071] It is understandable that when using the roll-to-roll method for transmission and pressing, since the battery cell 3 has a limited size, the flexible film 2 can be cut according to the different sizes of the battery cell 3 to form a matching size.

[0072] In some embodiments, when the flexible film 2 is patterned, in order to match the pattern / injection area on the surface of the battery cell 3, the edge alignment or alignment mark of the battery cell 3 is also used for patterning.

[0073] In step S300, as Figure 6 As shown, the step of printing grid lines on the battery cell 3 with the flexible mold 20 using the printing plate 130 includes:

[0074] Identify the position information of the battery cell 3; in some embodiments, the position information of the battery cell 3 can be identified by using an industrial camera to identify the coordinates of a specific shape, which may include the edge of the battery cell 3 or alignment marks on the flexible mold 20.

[0075] Based on the position information, the printing plate 130 is aligned with the flexible mold 20, so that the second grid line opening 1301 is opposite to the first grid line opening 201, and there is a set interval between the printing plate 130 and the flexible mold 20. When the printing plate 130 prints on the battery cell 3, the system obtains the coordinate position of the specific graphic and the actual position of the printing plate, compares and calculates the offset, and adjusts the position of the battery cell 3 or the printing plate 130 according to the offset to ensure that the first grid line opening 201 and the second grid line opening 1301 are opposite to each other, or the deviation does not exceed the set offset.

[0076] The printing plate 130 is coated with a scraping coating, wherein the scraping direction is consistent with the length direction of the second grid line opening 1301, and the scraping pressure is in the range of 20N to 80N.

[0077] Preferably, the spacing between the printing plate 130 and the flexible mold 20 is between 0.1 mm and 1 mm, the thickness of the flexible mold 20 is between 5 micrometers and 15 micrometers, and the width of the first grid opening 201 is between 5 micrometers and 50 micrometers.

[0078] In some embodiments, removing the flexible mold 20 includes:

[0079] The flexible mold 20 between the unwinding mechanism 10a and the winding mechanism 10b is wound up by the winding mechanism 10b, so that the flexible mold 20 is pulled away from the battery cell 3.

[0080] This application does not impose any special limitations on the drying process; drying can be carried out by means of a vacuum furnace, ultraviolet irradiation, or laser heating. Preferably, in the drying process of the intermediate solar cells, the drying temperature is in the range of 100°C to 300°C, and the drying time is in the range of 15 seconds to 3 minutes.

[0081] As another alternative implementation, the flexible mold 20 of this application may not be disposed on the battery cell 3, but directly disposed on the lower surface of the printing plate 130, such as... Figure 5 As shown, in one specific embodiment, the patterned flexible mold 20 is attached to the underside of the printing plate 130 via edge attachment, with the spacing between the printing plate 130 and the flexible mold 20 preferably between 0.1 mm and 1 mm. The pattern alignment of the attached flexible mold 20 is performed by aligning the marks of the flexible mold 20 with the marks of the printing plate 130 under an industrial microscope. In some embodiments, the printing mechanism 13 further includes an outer frame 131 located at the edge of the printing plate 130, which is used to fix the printing plate 130 and provide tension.

[0082] As a second aspect of this application, a solar cell manufacturing apparatus 1 is disclosed, such as... Figures 2 to 6As shown, the system includes: a transport platform 15, a flexible mold 20, an auxiliary mechanism, a printing mechanism 13, a drying mechanism 14, and a film removal mechanism 16. The transport platform 15 is used to transport the battery cell 3. The auxiliary mechanism, printing mechanism 13, drying mechanism 14, and film removal mechanism 16 are arranged sequentially along the transport direction of the transport platform 15. The auxiliary mechanism is used to place the flexible mold 20 on the surface of the battery cell 3 to be printed. The flexible mold 20 has multiple through first grid line openings 201. The printing mechanism 13 includes a printing plate 130. The printing plate 130 has multiple second grid line openings 1301. The printing mechanism 13 is used to print grid lines on the battery cell 3 with the flexible mold 20 on it through the printing plate 130, so that the first grid line openings 201 and the second grid line openings 1301 correspond one-to-one. The drying mechanism 14 is used to dry the battery cell 3. The film removal mechanism 16 is used to remove the flexible mold 20 from the battery cell 3.

[0083] The auxiliary mechanism includes a winding mechanism 10b, an unwinding mechanism 10a, and a pressing mechanism. The winding mechanism 10b and the unwinding mechanism 10a are arranged opposite to each other along the transmission direction. The unwinding mechanism 10a is used to unwind the flexible film 2, and the winding mechanism 10b is used to wind the flexible film 2. The flexible film 2 can be transmitted to the top of the battery cell 3 with a set tension through the unwinding mechanism 10a and the winding mechanism 10b. The pressing mechanism includes a first pressing roller 11a and a second pressing roller 11b arranged opposite to each other. The first pressing roller 11a is located at the bottom of the battery cell 3, and the second pressing roller 11b is located at the top of the flexible film 2. The flexible film 2 and the battery cell 3 can be rolled together by the first pressing roller 11a and the second pressing roller 11b.

[0084] The present application will be further explained and illustrated below through examples.

[0085] Example 1

[0086] At least one battery cell is transmitted via a transmission platform;

[0087] A flexible mold is set on the printing surface of each battery cell, wherein the flexible mold has multiple through-holes for the first grid lines. Specifically, the flexible film is unwound by an unwinding mechanism and wound by a winding mechanism to transmit tension to the top of the battery cell. The tension is set in the range of 1 N / cm to 10 N / cm. A pressing mechanism is used to bond the flexible film and the battery cell together. The pressing mechanism includes a first pressing roller and a second pressing roller arranged opposite to each other. The first pressing roller is located at the bottom of the battery cell, and the second pressing roller is located at the top of the flexible film. The flexible film and the battery cell are bonded by roll pressing using the first pressing roller and the second pressing roller. The flexible mold includes a photosensitive film. The photosensitive film is patterned by photolithography to obtain the flexible mold. The thickness of the flexible mold is between 5 micrometers and 15 micrometers, and the width of the first grid line openings is between 5 micrometers and 50 micrometers.

[0088] A battery cell with a flexible mold is printed with grid lines using a printing plate to obtain an intermediate battery cell. The printing plate has multiple second grid line openings, and the first grid line openings correspond one-to-one with the second grid line openings. The position information of the battery cell is identified, and based on the position information, the printing plate and the flexible mold are aligned so that the second grid line openings are opposite the first grid line openings. The gap between the printing plate and the flexible mold is between 0.1 mm and 1 mm. The printing plate is then coated with a coating in the same direction as the length of the second grid line openings, and the coating pressure is in the range of 20 N to 80 N.

[0089] The intermediate battery cells are dried.

[0090] Remove the flexible mold to obtain solar cell sample 1. Specifically, use a winding mechanism to wind up the flexible mold between the unwinding mechanism and the winding mechanism, so that the flexible mold is pulled away from the intermediate solar cell.

[0091] Comparative Example

[0092] Using the same printing preparation method as in Example 1, the difference is that this comparative example does not introduce a flexible mold during the printing process to obtain solar cell sample 2.

[0093] Test case

[0094] The electrical performance of the solar cell samples from Example 1 and the comparative example was tested, and the results are shown in Table 1. The microstructure and dimensions of the grid lines in Sample 1 and Sample 2 were observed and measured. The grid line morphology is shown in [Table 1]. Figure 7 and Figure 8 Regarding the slurry used in the examples, Figure 7 The grid lines formed by the flexible mold-assisted printing of the present invention have a linewidth of 14 to 16 micrometers and a height of 5 to 6 micrometers. The grid lines not only have a smaller linewidth but also a larger aspect ratio. Furthermore, the overall grid line exhibits uniform dimensions and minimal deviation despite the reduced size. Figure 8 The linewidth of the comparative gate lines is between 23 and 25 micrometers, and the height of the gate lines is between 4 and 5 micrometers.

[0095] Table 1 Electrical performance test data of solar cell samples

[0096]

[0097] As shown in Table 1, the flexible mold of this invention results in a more uniform and stable grid line morphology during the grid line printing process of the solar cell. This leads to improvements in both the open-circuit voltage and short-circuit current of the final solar cell, as well as increased conversion efficiency. In contrast, the comparative example, lacking a flexible mold for grid line printing, suffers from difficulty in controlling the grid line morphology, resulting in lower open-circuit voltage and short-circuit current, and consequently, reduced conversion efficiency.

[0098] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. A method for preparing a solar cell, characterized in that, The preparation method includes: Provide at least one battery cell; A flexible mold is set on the printing surface of each battery cell. The flexible mold has multiple through first grid line openings. A flexible film is set on the printing surface of the battery cell with a set tension. The flexible film is patterned to obtain the flexible mold. A battery cell with a flexible mold is printed with grid lines using a printing plate to obtain an intermediate battery cell. The printing plate is provided with a plurality of second grid line openings, and the first grid line openings correspond one-to-one with the second grid line openings, so that the paste flowing out from the second grid line openings fills the first grid line openings. The intermediate battery cell is dried. Remove the flexible mold to obtain the solar cell.

2. The preparation method according to claim 1, characterized in that, The flexible mold includes a photosensitive film, and the patterning process of the flexible film includes: The photosensitive film is patterned using photolithography to obtain a flexible mold.

3. The preparation method according to claim 1, characterized in that, The process of setting the flexible film at a set tension on the printing surface of the battery cell includes: The flexible film is unwound by an unwinding mechanism and wound up by a winding mechanism, and then transmitted to the top of the battery cell at the set tension. A pressing mechanism is used to bond the flexible film and the battery cell together. The pressing mechanism includes a first pressing roller and a second pressing roller arranged opposite to each other. The first pressing roller is located at the bottom of the battery cell, and the second pressing roller is located at the top of the flexible film. The flexible film and the battery cell are bonded together by roll pressing using the first pressing roller and the second pressing roller.

4. The preparation method according to claim 3, characterized in that, Removing the flexible mold includes: The winding mechanism is used to wind up the flexible mold between the unwinding mechanism and the winding mechanism, so that the flexible mold is pulled away from the intermediate battery cell.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The process of printing grid lines on a battery cell with a flexible mold using a printing plate includes: Identify the position information of the battery cell; Based on the position information, the printing plate and the flexible mold are aligned so that the second grid line opening is opposite to the first grid line opening, and there is a set interval between the printing plate and the flexible mold; The printing plate is coated with a scraping agent, wherein the scraping direction is consistent with the length direction of the second grid line opening.

6. The preparation method according to claim 5, characterized in that, The coating pressure is in the range of 20N to 80N.

7. The preparation method according to any one of claims 1 to 4, characterized in that, The spacing between the printing plate and the flexible mold is between 0.1 mm and 1 mm, the thickness of the flexible mold is between 5 micrometers and 15 micrometers, and the width of the first grid opening is between 5 micrometers and 50 micrometers.

8. A solar cell manufacturing equipment, characterized in that, include: The system comprises a transport platform, a flexible mold, an auxiliary mechanism, a printing mechanism, a drying mechanism, and a film removal mechanism. The transport platform is used to transport solar cells. The auxiliary mechanism, printing mechanism, drying mechanism, and film removal mechanism are arranged sequentially along the transport direction of the transport platform. The auxiliary mechanism is used to first place the flexible mold on the surface of the solar cell to be printed with a set tension, and then perform patterning processing on the surface of the flexible mold to obtain a flexible mold with multiple through-holes of the first grid lines. The printing mechanism includes a printing plate with multiple through-holes of the second grid lines. The printing mechanism is used to print grid lines on the solar cell with the flexible mold on it through the printing plate, so that the first grid lines correspond one-to-one with the second grid lines. The drying mechanism is used to dry the solar cells. The film removal mechanism is used to remove the flexible mold from the solar cells.

9. The solar cell production equipment according to claim 8, characterized in that, The auxiliary mechanism includes a winding mechanism, an unwinding mechanism, and a pressing mechanism. The winding mechanism and the unwinding mechanism are arranged opposite to each other along the transmission direction. The unwinding mechanism is used to unwind the flexible film, and the winding mechanism is used to wind the flexible film. The flexible film can be transmitted to the top of the solar cell with a set tension through the unwinding mechanism and the winding mechanism. The pressing mechanism includes a first pressing roller and a second pressing roller arranged opposite to each other. The first pressing roller is located at the bottom of the solar cell, and the second pressing roller is located at the top of the flexible film. The flexible film and the solar cell can be rolled together by the first pressing roller and the second pressing roller.

Images