Printing apparatus for secondary printing of a grid line

Abstract

The application relates to a printing device for secondary printing of grid lines, comprising a printing and drying table for carrying a solar cell, a printing device for printing the grid lines on the solar cell, and a laser drying device for drying the grid lines to improve the stability of the appearance of the grid lines. The application sets the printing and drying table, so that the carried solar cell can be printed on the table, and the printed solar cell is still dried on the table, avoiding the need for positioning caused by switching the carrying table, and reducing the alignment requirements of the printing device. The application sets the laser drying device, which can avoid the solidification of the printing paste caused by the energy dispersion of the heating device, which is not conducive to continuous printing, and can also avoid the problem that the energy dispersion causes the service life of the steel mesh and the stability of the printed pattern to decrease, thereby improving the feasibility of the secondary printing of the grid lines and the stability of the appearance of the grid lines.

Description

Technical Field

[0001] This application relates to the field of solar cell manufacturing and processing technology, and specifically to a printing device for secondary printing of grid lines. Background Technology

[0002] Battery printing technology is constantly evolving. With advancements in stencil manufacturing technology, the grid lines can be made increasingly finer. Especially with the increasing marketization of stencils, the printing width of fine grid lines has reached 1μm. As the grid lines become finer, line resistance has become a bottleneck restricting battery efficiency; therefore, improving grid line resistance remains a challenge.

[0003] The conventional approach involves printing the battery once, drying it, and then printing it a second time to increase the grid line height and reduce line resistance. However, the existing technology for secondary grid line printing still has the following technical problems: 1) It requires high alignment of the stencil and equipment, and requires an additional printing machine and corresponding labor costs; 2) The heating device has weak and diffused energy, which affects the morphology of the grid lines after secondary printing. Utility Model Content

[0004] To address the aforementioned technical problems, this application provides a printing apparatus for secondary printing of grid lines.

[0005] The technical solution adopted in this application to solve the above-mentioned technical problems is a printing equipment for secondary printing of grid lines, comprising: a printing and drying table for supporting solar cells; a printing device for printing the grid lines on the solar cells; and a laser drying device for drying the grid lines to improve the stability of the morphology of the grid lines.

[0006] In one embodiment of this application, the laser drying apparatus includes a laser lamp configured to dry the grid lines in a graphical manner.

[0007] In one embodiment of this application, the printing apparatus further includes: a transfer mechanism for transferring at least one of the printing drying tables to the printing device so that the printing device prints the grid lines on the solar cell, and / or for transferring at least one of the printing drying tables to the laser drying device so that the laser drying device dries the grid lines.

[0008] In one embodiment of this application, the transmission mechanism includes a turntable, and the printing drying table is disposed on the turntable.

[0009] In one embodiment of this application, the number of laser drying devices is less than the number of printing drying tables.

[0010] In one embodiment of this application, the turntable has a circular outline and has a first end and a second end opposite to each other. The printing equipment further includes a first transmission device and a second transmission device. The first transmission device is disposed at the first end, and the second transmission device is disposed at the second end. The first transmission device is used to transfer the solar cell to the printing drying table, and the second transmission device is used to remove the solar cell from the printing drying table.

[0011] In one embodiment of this application, the transmission mechanism is located below the printing drying table.

[0012] In one embodiment of this application, the number of the printing drying table, the printing device, and the laser drying device are equal and correspond one-to-one with each other.

[0013] In one embodiment of this application, the printing apparatus further includes a conveying device for conveying the solar cell to the printing drying table, or for removing the solar cell from the printing drying table.

[0014] In one embodiment of this application, the printing apparatus includes a screen printing apparatus, which includes a single screen.

[0015] This application, by setting up a printing and drying table, allows the solar cells to be printed on this table and then dried on the same table after printing. This avoids the positioning problems that need to be solved when switching the table during printing and drying, reducing the alignment requirements of the printing equipment. Furthermore, by incorporating a laser drying device, this application avoids the problem of the printing paste solidifying due to energy dissipation from the heating device, which is detrimental to continuous printing. It also avoids the problem of reduced stencil life and printing pattern stability caused by energy dissipation, thereby improving the feasibility of secondary printing of grid lines and the stability of the grid line morphology. Attached Figure Description

[0016] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings, wherein:

[0017] Figure 1 This is a simplified block diagram of a printing apparatus according to an embodiment of this application;

[0018] Figure 2 This is a schematic diagram of the structure of a printing apparatus according to another embodiment of this application. Detailed Implementation

[0019] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0020] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein, and therefore the present invention is not limited to the specific embodiments disclosed below.

[0021] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0022] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0023] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0024] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. However, the embodiments shown below are examples of a printing apparatus for secondary printing of grid lines to embody the technical concept of the present invention, and the printing apparatus for secondary printing of grid lines of the present invention is not specifically defined as follows. Furthermore, in order to facilitate understanding of the scope of the claims, the components shown in the "Claims" and "Summary of the Utility Model" columns are assigned numbers corresponding to the components shown in the embodiments. However, the components shown in the claims are not intended to be specific to the components of the embodiments. In particular, the dimensions, materials, shapes, and relative arrangements of the constituent components described in the embodiments are not intended to limit the scope of the present invention unless specifically stated otherwise, but are merely illustrative examples.

[0025] However, the dimensions or positional relationships of the components shown in the accompanying drawings are sometimes exaggerated for clarity. Therefore, in the following description, detailed descriptions of the same names and symbols representing the same or homogeneous components are appropriately omitted. Furthermore, the elements constituting this utility model can be multiple elements composed of the same components, thus allowing one component to function as multiple elements; conversely, multiple components can share the function of one component. Additionally, the content described in some embodiments and implementations can be applied to other embodiments and implementations. Furthermore, in this specification, "upper" is not limited to the case of being formed in contact with an upper surface, but also includes the case of being formed separately on top, and also includes the meaning of an interlayer between layers.

[0026] The printing technology for solar cells is constantly evolving. With advancements in stencil fabrication technology, printed grid lines are becoming increasingly finer. TOPCon cells, a type of solar cell, are N-type silicon substrate cells. An ultrathin layer of silicon oxide is prepared on the back of the cell, followed by the deposition of a doped silicon layer. These two layers together form a passivated contact structure, effectively reducing surface recombination and metal-to-metal recombination, providing greater potential for further improvements in cell conversion efficiency. However, with the refinement of the grid lines, line resistance has become a bottleneck restricting cell efficiency. Therefore, improving grid line resistance remains a challenge. A conventional approach involves drying the cells after printing and then performing a second printing process to increase the grid line height and reduce line resistance.

[0027] In existing technologies, the secondary printing process of solar grid lines generally involves: first, printing the grid lines at the first printing location; then, transferring the solar cell with the printed grid lines to the first drying location for the first drying; after drying, transferring it to the next printing location for the second grid line printing; and then transferring the solar cell with the second grid line printing to the next drying location for the second drying. During this process, the solar cell needs to be constantly switched between different mounting platforms. Since the grid line printing method for solar cells is generally screen printing, each printing requires a matching screen. The secondary printing process requires two printing machines, thus also requiring two matching screens. The precision requirements for these two matching screens are quite high; they must be perfectly aligned to complete the secondary printing. Similarly, the alignment precision requirements for the printing equipment are also high; the two matching screens must be perfectly aligned, and the printing equipment cannot have any deviation during alignment. Furthermore, the presence of multiple printing and drying locations increases labor costs.

[0028] Furthermore, while existing technologies include printing and drying methods that do not require switching the printing platform, the drying devices are energy-dissipating heating devices, including heating tubes, with infrared lamps being commonly used. Because heating tubes exhibit significant energy dissipation and heat loss, and their energy is relatively weak, using them often leads to the following problems: 1) During heating and drying, the area around the printing platform is affected by the heat from the heating tubes. However, the surface of the platform contains a fluid-like paste, and the rheological properties of the paste severely affect the printing quality of the battery. Prolonged drying and heating cause the organic or inorganic substances in the paste on the platform to evaporate quickly, and the paste itself to solidify, which is detrimental to continuous printing; 2) The alignment screen is generally made of steel, and steel itself conducts heat quickly. If heating tubes are used, it will severely affect the lifespan of the steel screen and the stability of the printed pattern. If the pattern is unstable, accurate registration cannot be achieved in the second printing; 3) The heating energy from the heating tubes is weak, and when the drying time is short, the underlying printing cannot be completely cured. All of these problems result in unstable grid line morphology after printing, and the grid line height cannot reach the ideal level.

[0029] To address the aforementioned problems, this application provides a printing apparatus for secondary printing of grid lines. Figure 1 A simplified block diagram of a printing apparatus according to an embodiment of this application is shown. Figure 1 As shown, the present application provides a printing apparatus 10 for secondary printing of grid lines, comprising: a printing and drying table 11 for supporting solar cells; a printing device 12 for printing grid lines on solar cells; and a laser drying device 13 for drying the grid lines to improve the stability of the grid line morphology.

[0030] This application, by setting up a printing and drying table, allows the solar cells to be printed on this table and then dried on the same table after printing. This avoids the positioning problems that need to be solved when switching the table during printing and drying, reducing the alignment requirements of the printing equipment. Furthermore, by incorporating a laser drying device, this application avoids the problem of the printing paste solidifying due to energy dissipation from the heating device, which is detrimental to continuous printing. It also avoids the problem of reduced stencil life and printing pattern stability caused by energy dissipation, thereby improving the feasibility of secondary printing of grid lines and the stability of the grid line morphology.

[0031] In some embodiments, the solar cell has its grid lines printed above the printing and drying table 11, and is also dried above the printing and drying table 11. During both the grid line printing and drying processes, the solar cell is positioned in a fixed location above the printing and drying table 11. Therefore, during the grid line printing and drying steps, the solar cell does not need to switch between different support tables, thus reducing the difficulty of alignment during the secondary grid line printing and lowering the precision requirements on the printing equipment and alignment screen.

[0032] In some embodiments, the printing device 12 and the laser drying device 13 are both disposed above the printing and drying table. In some embodiments, in order to achieve better printing and drying results, the relative positions of the printing and drying table 11, the printing device 12 and the laser drying device 13 can be adaptively adjusted.

[0033] In some embodiments, the printing apparatus 12 includes a screen printing apparatus, which includes a single screen. It is understood that since the same printing apparatus 12 can be used to complete secondary printing, a single screen can be used to complete secondary printing, solving the screen matching problem and saving material resources.

[0034] In some embodiments, the laser drying apparatus 13 includes a laser lamp configured to dry the grid lines in a patterned manner. In some embodiments, patterning can be achieved using methods conventional in the art, such as using a combination of cylindrical and focusing lenses to shape the laser spot from a circle to a rectangle, ellipse, or trapezoid, thereby transforming the laser into a patterned heat source. By setting the laser lamp and heating in a patterned manner, the laser energy acts only on the printed pattern, without affecting the silicon substrate or the printing equipment (stencil), thus improving the stability of the grid line morphology. During printing, the laser energy is concentrated on the grid lines to be dried, and energy dispersion will not affect the rheological properties of the paste on the printing drying table 11, allowing for continuous secondary printing on the same printing press for extended periods. Furthermore, energy dispersion will not affect the lifespan of the stencil in the printing apparatus 12, thus preventing instability in the printed pattern. In addition, the high laser energy allows for quick completion of the required curing conditions; even with short drying times, the paste at the bottom of the grid lines is easily dried and cured, making secondary overprinting of the pattern entirely feasible.

[0035] In some embodiments, the morphology of the grid lines in this application includes the length, height, and width of the printed grid lines. This application primarily discusses the height of the grid lines. It is understood that, given the same length and width, a higher grid line height results in lower grid resistance. Therefore, improving the height of the grid lines and the stability of the printed morphology is crucial for improving battery conversion efficiency.

[0036] In some embodiments, the number of printing drying tables 11, printing devices 12, and laser drying devices 13 are equal and correspond one-to-one. Accordingly, in some embodiments, the secondary printing process can be as follows: A solar cell is placed above the printing drying table 11, and the printing device 12 is turned on to perform the first printing of grid lines. After the first printing of the grid lines, the printing device 12 is turned off or removed, and the laser drying device 13 is moved above the printing drying table 11 and turned on to allow the first-printed pattern (grid lines) to be initially dried, ensuring the basic linear shape and preventing it from being crushed during secondary printing. After the first drying, the laser drying device 13 is turned off or removed, and the printing device 12 is moved above the printing drying table 11 and turned on to perform secondary printing. In the above embodiments, the secondary printing method is secondary ink return printing, that is, printing again before the ink from the first printing is completely dry. Through secondary ink return printing, the height of the grid lines can be further increased. In the prior art, the height of the grid lines is generally 6µm, while the height of the grid lines after the second ink return printing in this application can reach 9-10µm.

[0037] In some embodiments, the printing apparatus 10 further includes a conveying device for transferring the solar cell to or removing it from the printing drying table 11. In some embodiments, the conveying device includes moving the solar cell by means of gripping or a conveyor belt.

[0038] In the following embodiments, this application also provides some solutions that are conducive to further improving production efficiency.

[0039] In some embodiments, the printing apparatus further includes: a transfer mechanism for transferring at least one of the printing drying tables to a printing device to print grid lines on a solar cell, and / or for transferring at least one of the printing drying tables to a laser drying device to dry the grid lines.

[0040] It should be understood that in the above embodiments, the number of printing drying tables is greater than or equal to two. By setting up a transmission mechanism, on the one hand, the transmission efficiency is improved, and on the other hand, the printing drying tables, printing devices, and laser drying devices do not need to be set up in a one-to-one correspondence. The number of printing drying tables, printing devices, and laser drying devices can be set according to actual production needs, thus saving production resources.

[0041] Figure 2 A schematic diagram of the structure of a printing apparatus 20 according to another embodiment of this application is shown. Figure 2As shown, in some embodiments, the transfer mechanism includes a turntable 21, on which a printing drying table 22 is disposed. In some embodiments, the turntable 21 is configured to rotate at least one of the plurality of printing drying tables 22 to at least one printing device, and / or to rotate at least one printing drying table 22 to at least one laser drying device. By using the turntable 21, the printing drying table can be transferred to complete printing and drying in a smaller space, saving space resources.

[0042] In some embodiments, the positions of the printing apparatus and the laser drying apparatus are fixed. In some embodiments, one printing apparatus or one laser drying apparatus is disposed above each printing drying table 22, then the sum of the number of printing apparatuses and laser drying apparatuses equals the number of printing drying tables 22. In some embodiments, the printing apparatus and laser drying apparatus are arranged alternately at multiple printing drying tables 22. In some embodiments, the number of laser drying apparatuses is less than the number of printing drying tables 22. In some embodiments, the number of printing apparatuses is less than the number of printing drying tables 22. For example, the number of laser drying apparatuses is 2, the number of printing apparatuses is 2, and the number of printing drying tables 22 is 4. In some embodiments, the number of laser drying apparatuses and printing apparatuses can be the same or different. For example, a laser drying apparatus and one printing apparatus, or multiple printing apparatuses and one laser drying apparatus. In some embodiments, the specific number of laser drying apparatuses, printing apparatuses, and printing drying tables 22 can be set according to actual needs.

[0043] It is understandable that when the turntable 21 rotates, the positions of all printing drying tables 22 will rotate with the turntable 21, while the positions of the printing unit and the laser drying unit are fixed. Therefore, for a printing drying table 22, the position after rotation stops is the location of either a printing unit or a laser drying unit. For example, the printing drying table 22 may rotate from a position directly below the printing unit to a position directly below the laser drying unit, switching from the printing process to the drying process, or it may rotate from directly below the laser drying unit to a position directly below the printing unit, switching from the drying process to the printing process. For two printing drying tables 22, they may experience opposite processes at the same time; for example, one printing drying table 22 may switch from the drying process to the printing process, while the other printing drying table 22 switches from the printing process to the drying process.

[0044] like Figure 2 As shown, the printing drying table 22 also includes a solar cell 23. In some embodiments, the printing apparatus further includes a vacuum suction cup disposed above the turntable 21 for fixing the solar cell 23 in a fixed position on the turntable 21 during rotation.

[0045] In some embodiments, the printing apparatus further includes a positioning camera. After the turntable 21 rotates, the positioning camera scans the position of the solar cell 23. The operating system adjusts the position of the solar cell 23 based on the result from the positioning camera before printing. By incorporating a vacuum suction cup and a positioning camera, deviation of the solar cell's position after the turntable rotates is avoided.

[0046] like Figure 2 As shown, in some embodiments, the transfer mechanism (turntable 21) is located below the printing drying table 22. In some embodiments, the transfer mechanism (turntable 21) may also be located above the printing drying table 22, moving the printing drying table by clamping. In some embodiments, the transfer mechanism may also include other commonly used transfer mechanisms such as a conveyor belt.

[0047] like Figure 2 As shown, in some embodiments, the turntable 21 has a circular outline and has a first end 211 and a second end 212 opposite to each other. The printing equipment 20 also includes a first transmission device 24a and a second transmission device 24b. The first transmission device 24a is disposed at the first end 211 and the second transmission device 24b is disposed at the second end 212. The first transmission device 24a is used to transfer the solar cell 23 to the printing drying table 22, and the second transmission device 24b is used to remove the solar cell 23 from the printing drying table 22.

[0048] In some embodiments, the turntable 21 may also have a symmetrical structure such as a square. The first transmission device 24a and the second transmission device 24b may be configured as a conveyor belt. For example, after the first transmission device 24a transmits a solar cell 23 to a printing drying table 22, the turntable 21 rotates, causing the printing drying table 22 to rotate to the printing device, while the next printing drying table 22 arrives at the first transmission device 24a to receive the next solar cell 23.

[0049] In some embodiments, the secondary printing process can be as follows: the first transfer device 24a places multiple solar cells 23 one-to-one on multiple printing drying tables 22, and rotates the turntable 21 to move at least one printing drying table 22 under the printing device for the first printing; after the first printing is completed, the printing drying table 22 where the first-printed solar cell is located is rotated to the under of the laser drying device for the first drying, while the solar cells on the other printing drying tables 22 are rotated to the under of the printing device for the first printing; then, the printing drying table 22 where the first-dried solar cell is located is rotated to the under of the printing device for the second printing, while the solar cells that have completed the first printing are rotated to the under of the laser drying device for the first drying; then, the solar cells that have been printed the second time are rotated to the under of the laser drying device for the second drying, while the solar cells on the remaining printing drying tables 22 are printed or dried; the solar cells that have completed the second drying are transferred away by the second transfer device 24b and enter the subsequent processing flow, while the remaining solar cells continue to be printed or dried until they have completed the second drying and are transferred away by the second transfer device 24b.

[0050] This application, by setting up a printing and drying table, avoids the positioning problem caused by moving the support table during printing and drying, thus reducing the alignment requirements of the printing equipment. This application, by setting up a laser drying device, improves the feasibility of secondary printing of grid lines and the stability of grid line morphology. This application, by setting up a transmission mechanism, improves transmission efficiency and eliminates the need for a one-to-one correspondence between the printing and drying table, printing equipment, and laser drying device. The number of printing and drying tables, printing equipment, and laser drying devices can be set according to actual production needs, saving production resources.

[0051] While the foregoing disclosure has discussed various examples of utility model embodiments that are currently considered useful, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments. Rather, the claims are intended to cover all modifications and equivalent combinations that conform to the spirit and scope of the present utility model embodiments. For example, although the system components described above can be implemented by hardware devices, they can also be implemented solely by software solutions, such as installing the described system on existing servers or mobile devices.

[0052] Similarly, it should be noted that, in order to simplify the description of this utility model and thus aid in the understanding of one or more embodiments, the foregoing description of the embodiments of this utility model sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the object of this utility model requires more features than those mentioned in the claims. In fact, the embodiments have fewer features than all the features of the single embodiment disclosed above.

[0053] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are sometimes modified by the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±2%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this invention are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

Claims

1. A printing apparatus for secondary printing of grid lines, characterized in that, include: Printing drying table, used to support solar cells; A printing apparatus for printing the grid lines on the solar cell; as well as A laser drying apparatus is used to dry the grid lines to improve the stability of the grid line morphology.

2. The printing equipment as described in claim 1, characterized in that, The laser drying apparatus includes a laser lamp configured to dry the grid lines in a graphical manner.

3. The printing equipment as described in claim 1, characterized in that, Also includes: A transfer mechanism for transferring at least one of the printing drying tables to the printing device for printing the grid lines on the solar cell, and / or for transferring at least one of the printing drying tables to the laser drying device for drying the grid lines.

4. The printing equipment as described in claim 3, characterized in that, The transmission mechanism includes a turntable, and the printing and drying table is disposed on the turntable.

5. The printing equipment as described in claim 4, characterized in that, The number of laser drying devices is less than the number of printing drying tables.

6. The printing equipment as described in claim 4, characterized in that, The turntable has a circular outline and has a first end and a second end opposite to each other. The printing equipment also includes a first transmission device and a second transmission device. The first transmission device is disposed at the first end and the second transmission device is disposed at the second end. The first transmission device is used to transfer the solar cell to the printing and drying table, and the second transmission device is used to remove the solar cell from the printing and drying table.

7. The printing equipment as described in claim 3, characterized in that, The transmission mechanism is located below the printing and drying table.

8. The printing equipment as described in claim 1, characterized in that, The number of printing drying tables, printing devices, and laser drying devices are equal and correspond one-to-one with each other.

9. The printing equipment as described in claim 1, characterized in that, It also includes a transmission device for transferring the solar cell to the printing and drying table, or for removing the solar cell from the printing and drying table.

10. The printing equipment as claimed in claim 1, characterized in that, The printing apparatus includes a screen printing apparatus, which includes a single screen plate.

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