Full-opening solar cell printing plate

Abstract

The invention discloses a full-opening solar cell printing plate, and belongs to the technical field of solar cell printing. The full-opening solar cell printing plate comprises a frame, an annular auxiliary material piece and a graphical steel plate, the graphical steel plate is arranged on the annular auxiliary material piece, an avoiding area is larger than a graphical area of the graphical steel plate, the graphical steel plate comprises a buffer metal layer and a first metal layer, the graphical area of the buffer metal layer is provided with a plurality of first grid line holes, and the first grid line holes are communicated with the annular auxiliary material piece. A plurality of second grid line holes are formed in the pattern area of the first metal layer, at least one buffer metal layer is arranged on the pasting and printing face of the first metal layer, the first grid line holes are communicated with the corresponding second grid line holes, and the hardness of the buffer metal layer is smaller than that of the silicon wafer. According to the method, the surface of the steel plate can be matched with the uneven surface of the silicon wafer in the printing process, consumption of printing silver paste is saved, stable batch production is facilitated, and the electrical performance of a battery piece is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cell printing, and particularly to a full-opening solar cell printing plate. Background Art

[0002] As a key tool for printing solar cell electrodes, the screen printing stencil plays a crucial role in the development process of the photovoltaic industry. With the continuous progress of photovoltaic technology and the increasing requirements of the market for the performance of photovoltaic modules, stencil manufacturers have actively responded to market demands and successively introduced knotless stencils. This new type of stencil has achieved remarkable results in realizing printing with finer line widths and has met some of the requirements for electrode line widths in photovoltaic module production at that time to a certain extent. However, the photovoltaic industry has always been in a state of rapid development and change. On the one hand, the photovoltaic module market has put forward more stringent new requirements for the accuracy and performance of electrodes. Consumers and the industry have higher expectations for aspects such as the conversion efficiency, stability, and service life of photovoltaic modules. This requires finer electrode line widths and higher flatness of the wire grids to reduce resistance and improve current collection efficiency, thereby enhancing the overall performance of photovoltaic modules. On the other hand, battery technology is also constantly innovating. From traditional battery technologies to the emergence of new high-efficiency battery technologies such as heterojunction batteries and perovskite batteries, these new technologies have posed new challenges to the accuracy, stability, and compatibility with solar cells of printing stencils. Existing screen stencils gradually show limitations when facing these increasing requirements and are no longer able to meet the strict requirements for extremely fine line widths and flatness of wire grids.

[0003] Under this background, the full-opening steel stencil has emerged. With its unique manufacturing process and material properties, the full-opening steel stencil demonstrates excellent performance in realizing printing with extremely fine line widths. It can precisely control the line width of the electrode to reach the micron level, greatly improving the accuracy of the electrode. At the same time, the full-opening steel stencil can effectively ensure the flatness of the wire grid, reducing the problems of increased resistance and current loss caused by uneven wire grids. Thus, while meeting the requirements for extremely fine line widths, it also well meets the requirements for the flatness of the wire grid, providing strong support for the improvement of the performance of photovoltaic modules.

[0004] However, taking the Back Contact cell (hereinafter referred to as BC cell) as an example, its surface has a unique process structure. In order to realize the back contact structure design, the layout and shape of the surface electrode of the BC cell are very different from those of the traditional cell. This unique process makes it impossible for the fully open steel plate to achieve a perfect fit when it contacts the surface of the cell. During the printing process, due to the mismatch between the steel plate and the cell surface, the printed electrodes have thick lines and uneven line shapes. Thick electrode lines increase resistance and reduce current collection efficiency; uneven line shapes affect the connection stability between electrodes, which in turn has a negative impact on the conversion efficiency of the cell. At the same time, these printing problems will also increase the defective rate in the production process, reduce production efficiency, and increase production costs. In the printing process of Topcon cells, the fully open steel plate also exposed similar problems. As a new type of high-efficiency battery technology, Topcon cells have extremely high requirements for electrode accuracy and uniformity. However, when the fully open steel plate was printing the Topcon front cell and the back poly finger (similar in morphology to BC), thick lines and irregular line expansion also occurred. These printing defects not only affect the appearance quality of the battery cell, but more importantly, reduce the conversion efficiency of the battery cell, making it impossible for the battery cell to fully exert its due performance in actual applications. Moreover, irregular expansion lines may also cause safety hazards such as short circuits in the subsequent packaging and use of the battery cell.

[0005] This section provides background information related to the present application which is not necessarily prior art. Summary of the invention

[0006] The purpose of the present invention is to provide a fully-opened solar cell printing plate, so that the surface of the steel plate can fit the uneven surface of the silicon wafer during the printing process, which not only saves the consumption of printing silver paste, contributes to stable mass production, but also improves the electrical performance of the solar cell.

[0007] In order to achieve the above objectives, the following technical solutions are provided:

[0008] Fully open solar cell printed board, including:

[0009] A frame, the frame comprising a fixed edge, the fixed edge is circumferentially arranged to form a mounting area;

[0010] An annular auxiliary material is located in the installation area, the outer edge of the annular auxiliary material is connected to the fixed edge, and the inner edge of the annular auxiliary material is circumferentially surrounded to form an escape area;

[0011] The patterned steel plate is disposed on the annular auxiliary material member, the avoidance area is larger than the graphic area of the patterned steel plate, the patterned steel plate includes a buffer metal layer and a first metal layer, the graphic area of the buffer metal layer has a plurality of first grid holes, the graphic area of the first metal layer has a plurality of second grid holes, at least one layer of the buffer metal layer is disposed on the printing surface of the first metal layer, the first grid holes communicate with the corresponding second grid holes, and the hardness of the buffer metal layer is less than the hardness of the silicon wafer.

[0012] As an alternative to the printing plate for the full-opening solar cell, the patterned steel plate further includes:

[0013] A second metal layer, the graphic area of the second metal layer has a plurality of third grid holes, the second metal layer is disposed on the scraping surface of the first metal layer, and the third grid holes communicate with the corresponding second grid holes and the first grid holes in sequence.

[0014] As an alternative to the printing plate for the full-opening solar cell, the opening line widths of the first grid holes and the second grid holes are the same, and the opening line width of the third grid holes is greater than the opening line width of the second grid holes.

[0015] As an alternative to the printing plate for the full-opening solar cell, the material of the buffer metal layer is metal tin, tin alloy or metal aluminum.

[0016] As an alternative to the printing plate for the full-opening solar cell, the material of the first metal layer is nickel or nickel alloy.

[0017] As an alternative to the printing plate for the full-opening solar cell, the thickness of the buffer metal layer is not greater than the thickness of the first metal layer.

[0018] As an alternative to the printing plate for the full-opening solar cell, the thickness of the buffer metal layer is 1μm - 6μm; and / or

[0019] The thickness of the first metal layer is 5μm - 15μm.

[0020] As an alternative to the printing plate for the full-opening solar cell, the material of the second metal layer is nickel or nickel alloy; and / or

[0021] The thickness of the second metal layer is 5μm - 20μm.

[0022] As an alternative to the printing plate for the full-opening solar cell, the material of the annular auxiliary material member is nylon mesh.

[0023] As an alternative to the printing plate for the full-opening solar cell, the frame further includes a plurality of positioning holes, and the plurality of positioning holes are circumferentially and spaced apart on the fixed side.

[0024] Advantages of the present invention compared with the prior art:

[0025] The full-opening solar cell printing plate provided by the present invention covers one or more buffer metal layers with a hardness lower than that of the silicon wafer on the surface of the patterned steel plate, so that the surface of the patterned steel plate can fit with the uneven surface of the silicon wafer during the printing process. The silver paste is deposited on the battery silicon wafer after passing through the second grid line hole and the first grid line hole in sequence, avoiding the silver paste from overflowing from the gap between the steel plate and the uneven surface of the silicon wafer, ensuring that the grid line shape printed on the silicon wafer is uniform and regular, not only saving the consumption of the printed silver paste and achieving stable batch production, but also helping to improve the photoelectric conversion efficiency of the battery silicon wafer and enhancing the electrical performance of the battery wafer. Description of the drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the content of the embodiments of the present invention and these drawings.

[0027] Figure 1 It is an assembly schematic diagram of the full-opening solar cell printing plate in the embodiment of the present invention;

[0028] Figure 2 It is a top view of the frame in the embodiment of the present invention;

[0029] Figure 3 It is a top view of the annular auxiliary material in the embodiment of the present invention;

[0030] Figure 4 It is a top view of the patterned steel plate in the embodiment of the present invention;

[0031] Figure 5 It is a cross-sectional view of the patterned steel plate around the grid line hole in the embodiment of the present invention;

[0032] Figure 6 It is a schematic diagram of the first printing method (without buffer metal layer) of the Back Contact battery wafer in the embodiment of the present invention;

[0033] Figure 7 It is a schematic diagram of the second printing method (with buffer metal layer) of the Back Contact battery wafer in the embodiment of the present invention;

[0034] Figure 8 It is a schematic diagram of the first printing method (without buffer metal layer) of the Topcon battery wafer in the embodiment of the present invention;

[0035] Figure 9 Schematic diagram of the second printing method for Topcon solar cells in the embodiments of the present invention (with a buffer metal layer).

[0036] Reference numerals:

[0037] 100, squeegee; 200, silver paste; 300, Back Contact solar cell; 400, Topcon solar cell;

[0038] 1, frame; 2, annular auxiliary member; 3, patterned steel plate;

[0039] 11, fixed side; 12, installation area; 13, positioning hole;

[0040] 21, avoidance area;

[0041] 31, buffer metal layer; 311, first grid line hole; 32, first metal layer; 321, second grid line hole; 33, second metal layer; 331, third grid line hole. Detailed implementation manners

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0043] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0044] In the description of the present invention, it should also be noted that unless otherwise clearly defined and limited, the terms "installed" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection. 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 situations.

[0045] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0046] In order to save the consumption of printed silver paste, contribute to stable mass production, and improve the electrical performance of solar cells, the present embodiment provides a full-opening solar cell printing plate. The following will describe the specific content of the present embodiment in detail in combination with Figures 1 to 9 It should be noted that the graphic area mentioned in the present embodiment refers to the area occupied by processing multiple grid holes.

[0047] In the field of battery printing, especially in the solar cell printing process, the quality and performance of the printing screen play a crucial role in the final electrical performance and production efficiency of solar cells. The full-opening solar cell printing plate provided in the present embodiment is an innovative product carefully designed for the pain points existing in the current battery printing process, and its unique structure brings a new solution for improving the battery printing quality.

[0048] The full-opening solar cell printing plate mainly consists of a frame 1, an annular auxiliary member 2, and a patterned steel plate 3. The frame 1 serves as the support structure of the entire steel plate. The frame 1 includes fixed edges 11, and these fixed edges 11 are circumferentially enclosed to form an installation area 12, providing a stable platform for the installation of the annular auxiliary member 2 and the patterned steel plate 3. This frame 1 structure not only ensures the overall strength and stability of the steel plate but also lays a foundation for the precise installation of subsequent components.

[0049] The annular auxiliary member 2 is located within the installation area 12 formed by the frame 1, and its outer edge is tightly connected to the fixed edge 11, ensuring the stability of the annular auxiliary member 2 within the frame 1. The inner edge of the annular auxiliary member 2 is circumferentially enclosed to form an avoidance area 21, and this avoidance area 21 is larger than the graphic area of the patterned steel plate 3, enabling the silver paste 200 to flow smoothly through the avoidance area 21 of the annular auxiliary member 2 and the patterned steel plate 3.

[0050] The patterned steel plate 3 is the core component of the entire fully open solar cell printing plate, and it is disposed on the annular auxiliary material member 2. The patterned steel plate 3 includes a buffer metal layer 31 and a first metal layer 32. Multiple first grid holes 311 are distributed in the graphic area of the buffer metal layer 31, and the shapes, sizes, and spacings of these first grid holes 311 are precisely calculated and designed to meet the requirements of the grid line shape and accuracy for battery printing. The graphic area of the first metal layer 32 also has multiple second grid holes 321, and at least one layer of the buffer metal layer 31 is provided on the printing surface of the first metal layer 32. The first grid holes 311 communicate with the corresponding second grid holes 321. This communication design enables the silver paste 200 to smoothly pass through the two layers of grid holes during the printing process and finally deposit on the battery silicon wafer. It is particularly worth mentioning that the hardness of the buffer metal layer 31 is less than the hardness of the silicon wafer. This characteristic is one of the key innovations of this fully open solar cell printing plate. During the actual battery printing process, the surface of the silicon wafer often has a certain degree of unevenness, which is determined by the manufacturing process and material characteristics of the silicon wafer. If a traditional rigid steel plate is used for printing, there will be gaps between the steel plate and the uneven surface of the silicon wafer, resulting in the silver paste 200 overflowing from these gaps during the printing process, thereby affecting the shape and regularity of the grid lines. However, due to the hardness of the buffer metal layer 31 in this embodiment being less than the hardness of the silicon wafer, it can undergo a certain degree of deformation according to the unevenness of the silicon wafer surface during the printing process, enabling the surface of the patterned steel plate 3 to perfectly fit the uneven surface of the silicon wafer.

[0051] The technical effects brought about by this fit are multi-faceted. First of all, it can effectively prevent the silver paste 200 from overflowing from the gap between the steel plate and the uneven surface of the silicon wafer. The precise deposition of the silver paste 200 ensures that the shape of the grid lines is uniform and regular, avoiding problems such as uneven thickness and broken lines of the grid lines caused by the overflow of the silver paste 200. The uniform and regular grid lines can better collect and conduct current, reducing the resistance loss, thereby improving the photoelectric conversion efficiency of the battery silicon wafer. Secondly, due to the improvement of the grid line printing quality, the defective product rate caused by printing defects is reduced, achieving stable batch production. This not only reduces the production cost but also improves the production efficiency. In addition, the stable printing quality also helps to improve the overall electrical performance of the battery cells, such as open-circuit voltage, short-circuit current, and fill factor. The fully open solar cell printing plate provided in this embodiment effectively solves the printing quality problems caused by the uneven surface of the silicon wafer during the battery printing process through its unique structural design and the application of the buffer metal layer 31, providing strong technical support for the large-scale and efficient production of solar cells.

[0052] Furthermore, the patterned steel plate 3 further includes a second metal layer 33. The patterned area of the second metal layer 33 has a plurality of third grid line holes 331. The second metal layer 33 is disposed on the scraping surface of the first metal layer 32. The third grid line holes 331 are sequentially communicated with the corresponding second grid line holes 321 and the first grid line holes 311, forming a complete and unobstructed silver paste 200 channel. The primary and significant technical effect of adding the second metal layer 33 is to greatly improve the overall structural strength of the patterned steel plate 3. During the battery printing process, the patterned steel plate 3 needs to withstand the pressure from the squeegee 100 and repeated friction. Under long-term high-intensity printing operations, the traditional single-layer metal layer structure is prone to bending deformation due to stress concentration. Once the patterned steel plate 3 bends, it will not only affect the printing accuracy, resulting in problems such as grid line position deviation and line shape distortion, but also accelerate the wear of the steel plate, shorten its service life, and increase the production cost of the enterprise. The addition of the second metal layer 33 is equivalent to adding a strong support structure to the patterned steel plate 3. The three metal layers cooperate with each other to jointly bear the external pressure and stress, enabling the patterned steel plate 3 to maintain better flatness and stability during the printing process. Even after long-term continuous printing, the occurrence of bending deformation can be effectively avoided, ensuring the stability and consistency of the printing quality. From the perspective of printing quality, the patterned steel plate 3 with improved structural strength can better ensure the printing accuracy of the grid lines. Since the patterned steel plate 3 is no longer prone to bending, the squeegee 100 can apply pressure more evenly during the printing process, enabling the silver paste 200 to accurately deposit at the designated position on the battery silicon wafer through the third grid line holes 331, the second grid line holes 321, and the first grid line holes 311. The printed grid lines are more uniform and regular in shape, and the width and spacing can strictly meet the design requirements. Uniform and regular grid lines can significantly improve the light absorption and current collection efficiency of the battery silicon wafer, reduce resistance losses, and thus directly improve the photoelectric conversion efficiency of the battery silicon wafer. In the traditional printing process, printing defects caused by steel plate bending will increase the defective rate, and enterprises need to spend a lot of time and manpower for rework or reprinting, which not only reduces production efficiency but also increases production costs. In this embodiment, the patterned steel plate 3 with the added second metal layer 33 can maintain stable printing quality, greatly reducing the production of defective products and achieving stable batch production.

[0053] Furthermore, the opening line widths of the first gate line holes 311 and the second gate line holes 321 are the same, and the opening line width of the third gate line holes 331 is greater than that of the second gate line holes 321. The patterned steel plate 3 includes a three-layer structure, namely a buffer metal layer 31, a first metal layer 32, and a second metal layer 33, and the first gate line holes 311, the second gate line holes 321, and the third gate line holes 331 are respectively provided in each layer. Among them, the line width of the first gate line holes 311 is highly consistent with the line width required by the customer. This is because during the battery printing process, the customer has clear and strict requirements for the line width of the gate lines to meet the electrical performance indicators and design specifications of the battery. For example, in solar cells pursuing high photoelectric conversion efficiency, a thinner gate line width can reduce the light shielding of the gate lines and improve the light absorption rate of the battery. Therefore, accurately setting the line width of the first gate line holes 311 to the line width required by the customer is a crucial step in ensuring that the printed gate lines meet the battery performance requirements. The line width of the second gate line holes 321 is set with reference to the first gate line holes 311, and the opening line widths of the two are the same. This design is not arbitrary, but is based on a comprehensive consideration of the printing process and material properties. During the printing process, the silver paste 200 needs to be deposited on the battery silicon wafer through the first gate line holes 311 and the second gate line holes 321 in sequence. If the line widths of the first gate line holes 311 and the second gate line holes 321 are inconsistent, it may cause problems such as poor flow and uneven distribution of the silver paste 200 when passing through the two layers of gate line holes, thereby affecting the printing quality of the gate lines. Keeping the line widths of the two the same can ensure a stable flow state of the silver paste 200 when passing through the two layers of gate line holes, enabling the silver paste 200 to be evenly deposited on the silicon wafer to form gate lines with regular shapes and consistent widths. The opening line width of the third gate line holes 331 is greater than that of the second gate line holes 321, and it can be expanded outward by 10 μm - 200 μm on one side. This design has two important functions. On the one hand, it provides a storage space for printing. During the battery printing process, the supply of the silver paste 200 needs to be stable and sufficient to ensure continuous printing and good filling effect of the gate lines. The increase in the line width of the third gate line holes 331 enables more silver paste 200 to be accommodated during the printing process. When the squeegee 100 scrapes on the surface of the steel plate, the third gate line holes 331 can store a certain amount of silver paste 200, avoiding problems such as broken gate lines and incomplete filling due to insufficient supply of the silver paste 200. This is like setting a "silver paste storage depot" during the printing process, which can timely supplement the silver paste 200 required for printing and ensure the smooth progress of printing.

[0054] Furthermore, the material of the buffer metal layer 31 is metallic tin, tin alloy or metallic aluminum. By using special processing techniques, it is adsorbed onto the surface of the first metal layer 32 of the patterned steel plate 3 in multiple stages to form one or more layers of the buffer metal layer 31. Metallic tin has good ductility and plasticity and is relatively soft at room temperature, which enables it to well adapt to the unevenness of the silicon wafer surface. When the patterned steel plate 3 contacts the silicon wafer for printing, the buffer metal layer 31 made of metallic tin can undergo a certain degree of deformation to fill the tiny gaps between the steel plate and the silicon wafer, thus preventing the silver paste 200 from overflowing from these gaps and ensuring the printing quality of the grid lines. In addition, metallic tin also has a certain electrical conductivity. Although its electrical conductivity is slightly weaker than that of metals such as silver, in battery printing, it can play a good buffering and transitional role without affecting the overall electrical performance of the battery. A tin alloy is an alloy material formed by adding other metal elements to metallic tin. By adjusting the alloy composition, the performance of the buffer metal layer 31 can be further optimized. For example, adding an appropriate amount of copper element can increase the hardness and strength of the tin alloy while maintaining a certain ductility, enabling it to better withstand the pressure of the squeegee 100 during printing and adapt to the unevenness of the silicon wafer surface. Different tin alloy formulations can be customized according to specific printing requirements and battery types to meet diverse production needs. Metallic aluminum also has many characteristics suitable for being the material of the buffer metal layer 31. It is light in weight and low in cost, having a certain economic advantage in large-scale production. Moreover, a dense aluminum oxide protective film is easily formed on the surface of metallic aluminum, which can prevent aluminum from being corroded during printing, improving the stability and service life of the buffer metal layer 31. At the same time, metallic aluminum also has a certain softness and can fit well with the silicon wafer surface during printing, ensuring the printing accuracy and the quality of the grid lines.

[0055] In terms of the formation process of the buffer metal layer 31, it is adsorbed on the surface of the first metal layer 32 of the patterned steel plate 3 in multiple stages, thereby forming one or more buffer metal layers 31. This process of multiple-stage adsorption has many advantages. Adsorbing in multiple stages can precisely control the thickness and uniformity of each buffer metal layer 31. During each adsorption process, it is ensured that each buffer metal layer 31 can evenly cover the surface of the first metal layer 32, avoiding the situation of local over-thickness or under-thickness. This is crucial for ensuring the overall performance of the buffer metal layer 31, because a uniform thickness can ensure that the buffer metal layer 31 can be uniformly stressed and deformed during the printing process, and better adapt to the unevenness of the silicon wafer surface. Multiple adsorption can increase the total thickness of the buffer metal layer 31 and further improve its buffering effect. According to different printing requirements and the degree of unevenness of the silicon wafer surface, different numbers of buffer metal layers 31 can be adsorbed. For example, for a silicon wafer with a relatively large surface unevenness, the adsorption times can be appropriately increased to form a thicker buffer metal layer 31 to better fill the gap between the steel plate and the silicon wafer; while for a relatively flat silicon wafer surface, the adsorption times can be reduced to reduce production costs while ensuring the buffering effect. In addition, this special process method can also improve the bonding force between the buffer metal layer 31 and the first metal layer 32. During each adsorption process, the metal atoms of the buffer metal layer 31 will interact with the metal atoms of the first metal layer 32 to form certain chemical bonds or physical adsorption forces. Through multiple adsorption, this bonding force will be continuously enhanced, so that the buffer metal layer 31 can firmly adhere to the surface of the first metal layer 32 and is not easily detached during the printing process, ensuring the stability and reliability of printing.

[0056] Furthermore, the material of the first metal layer 32 is nickel or nickel alloy. Nickel, as a metal with excellent properties, has high strength, high hardness and good corrosion resistance. During the battery printing process, the patterned steel plate 3 needs to withstand the pressure applied by the squeegee 100 and repeated friction. The high strength and high hardness properties of the nickel material enable the first metal layer 32 to effectively resist these external forces, maintain its own shape and structural stability, and are not easily deformed or worn. This not only ensures the dimensional accuracy of the grid holes during the printing process, but also extends the service life of the patterned steel plate 3 and reduces the production cost of the enterprise. Nickel alloy is an alloy material formed by adding other metal elements to nickel. By adjusting the alloy composition, the performance of the first metal layer 32 can be further optimized. For example, adding an appropriate amount of chromium element can improve the corrosion resistance of the nickel alloy, so that it can still maintain good performance in harsh environments such as humidity, acid and alkali, which is crucial for the long-term stable operation of battery printing equipment. Different nickel alloy formulations can be customized according to specific printing requirements and battery types to meet diverse production needs.

[0057] Furthermore, the thickness of the buffer metal layer 31 is not greater than that of the first metal layer 32. When the buffer metal layer 31 cools, since metal materials contract during the cooling process, if the thickness of the buffer metal layer 31 is too large, the stress generated by its contraction may be transmitted to the first metal layer 32, resulting in bending stress on the surface of the first metal layer 32. This bending stress will affect the flatness of the patterned steel plate 3, and further affect the printing quality. For example, during the printing process, if the first metal layer 32 bends due to the stress generated by the cooling of the buffer metal layer 31, the pressure will be uneven when the squeegee 100 scrapes on the surface of the steel plate, resulting in uneven deposition of the silver paste 200 and problems such as distorted and uneven thickness of the grid lines. By controlling the thickness of the buffer metal layer 31 within the range not greater than that of the first metal layer 32, this situation can be effectively avoided, ensuring that the patterned steel plate 3 remains flat during the printing process and ensuring that the quality of the printed grid lines meets the requirements.

[0058] From the perspective of reducing the overall thickness of the patterned steel plate 3 and achieving lightweight, as the demand for miniaturization and lightweight of equipment in the solar cell industry increases, reducing the overall thickness of the patterned steel plate 3 has important practical significance. The thickness of the buffer metal layer 31 not being greater than that of the first metal layer 32 helps to minimize the thickness of the patterned steel plate 3 as much as possible while ensuring the buffering effect. The lightweight patterned steel plate 3 can not only reduce the overall weight of the equipment, reduce transportation and installation costs, but also improve the flexibility and operability of the equipment. For example, in some printing equipment with high space requirements, the lightweight patterned steel plate 3 can be more conveniently installed and debugged, improving production efficiency. In addition, reducing the weight can also reduce the energy consumption of the equipment during operation.

[0059] Exemplarily, the thickness of the buffer metal layer 31 is 1 μm - 6 μm; and / or the thickness of the first metal layer 32 is 5 μm - 15 μm.

[0060] Exemplarily, the material of the second metal layer 33 is nickel or nickel alloy; and / or the thickness of the second metal layer 33 is 5 μm - 20 μm. The effect of using nickel or nickel alloy for the second metal layer 33 is similar to that of using nickel or nickel alloy for the first metal layer 32, and will not be elaborated here.

[0061] Exemplarily, the material of the annular auxiliary member 2 is nylon mesh. The high-strength characteristic of the nylon mesh enables it to easily withstand external forces and is not prone to breakage or deformation. Even during long-term and high-intensity printing operations, the nylon mesh can maintain a stable structure to ensure the normal use of the annular auxiliary member 2. At the same time, its good toughness enables the nylon mesh to undergo a certain degree of elastic deformation when subjected to external impacts, absorb energy, reduce damage caused by impacts, and further extend the service life of the annular auxiliary member 2.

[0062] Exemplarily, the frame 1 further includes a plurality of positioning holes 13, and the plurality of positioning holes 13 are circumferentially spaced on the fixed edge 11. The frame 1 is made of high-strength alloy material, having good rigidity and corrosion resistance, ensuring that it will not deform during the printing process. There are precise positioning holes 13 around the frame 1 to ensure the consistency of the printing position each time.

[0063] In summary, during the actual use process, for the full-opening steel plate with the buffer metal layer 31 added, during the printing process of BC solar cells, compared with the case without using the buffer metal layer 31, the single-item defective rate of silicon wafer cracking decreases by 15%, and the defect of grid line outward expansion decreases by 35%. It effectively increases the service life of the steel plate, reduces the degradation or scrapping of silicon wafers caused by the amount of silicon wafer cracking, and effectively reduces the cost. For the full-opening steel plate with the buffer metal layer 31 added, during the printing process of Topcon solar cells 400, compared with the steel plate without the buffer metal layer 31, the degradation ratio of solar cells caused by grid line outward expansion decreases by 38%. At the same time, the service life is increased to 1.5 - 2 times the original, the single consumption of silver paste 200 is also relatively stable, reducing by 3 - 5 milligrams compared with the steel plate without the buffer layer, and the conversion efficiency is increased by 0.1%, effectively reducing the cost.

[0064] Note that the above is only the preferred embodiment of the present invention and the applied technical principle. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, it can also include more other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. Full-opening solar cell printing plate, characterized in that Comprising: A frame (1), the frame (1) includes a fixed edge (11), and an installation area (12) is circumferentially formed around the fixed edge (11); An annular auxiliary member (2), located within the installation area (12), the outer edge of the annular auxiliary member (2) is connected to the fixed edge (11), and an avoidance area (21) is circumferentially formed around the inner edge of the annular auxiliary member (2); A patterned steel plate (3), disposed on the annular auxiliary member (2), the avoidance area (21) is larger than the graphic area of the patterned steel plate (3), the patterned steel plate (3) includes a buffer metal layer (31) and a first metal layer (32), the graphic area of the buffer metal layer (31) has a plurality of first grid holes (311), the graphic area of the first metal layer (32) has a plurality of second grid holes (321), at least one layer of the buffer metal layer (31) is provided on the printing surface of the first metal layer (32), the first grid holes (311) communicate with the corresponding second grid holes (321), and the hardness of the buffer metal layer (31) is less than the hardness of the silicon wafer.

2. The fully open solar cell printing plate according to claim 1, characterized in that, The patterned steel plate (3) further includes: A second metal layer (33), the graphic area of the second metal layer (33) has a plurality of third grid holes (331), the second metal layer (33) is disposed on the scraping surface of the first metal layer (32), and the third grid holes (331) communicate with the corresponding second grid holes (321) and the first grid holes (311) in sequence.

3. The fully open solar cell printing plate according to claim 2, characterized in that, The opening line widths of the first grid holes (311) and the second grid holes (321) are the same, and the opening line width of the third grid holes (331) is greater than the opening line width of the second grid holes (321).

4. The fully open solar cell printing plate according to claim 3, characterized in that, The material of the buffer metal layer (31) is metal tin, tin alloy or metal aluminum.

5. The fully open solar cell printing plate according to claim 4, characterized in that The material of the first metal layer (32) is nickel or nickel alloy.

6. The fully open solar cell printing plate according to claim 5, characterized in that, The thickness of the buffer metal layer (31) is not greater than the thickness of the first metal layer (32).

7. The fully open solar cell printing plate according to claim 5, characterized in that, The thickness of the buffer metal layer (31) is 1μm - 6μm; and / or The thickness of the first metal layer (32) is 5μm - 15μm.

8. The fully open solar cell printing plate according to claim 2, wherein, The material of the second metal layer (33) is nickel or nickel alloy; and / or The thickness of the second metal layer (33) is 5μm - 20μm.

9. The fully open solar cell printing plate according to any one of claims 2-8, characterized in that The material of the annular auxiliary member (2) is nylon mesh.

10. The fully open solar cell printing plate according to claim 9, characterized in that, The frame (1) further includes a plurality of positioning holes (13), and the plurality of positioning holes (13) are circumferentially spaced on the fixed edge (11).

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