Battery piece, printing process thereof, printing production line and photovoltaic module

Abstract

The invention belongs to the technical field of solar cells, and provides a battery piece, a printing process thereof, a printing production line and a photovoltaic module. The battery piece printing process comprises the following steps: providing a battery piece; the step of printing the battery piece comprises the sub-steps of printing the battery piece by adopting a first printing method to generate a first grid line; the battery piece is printed through a second printing method, a second grid line is generated, and the second grid line intersects with the first grid line; the battery piece is dried, and the first grid line and the second grid line are dried together and form a whole. According to the scheme, after the first grid line and the second grid line of the battery piece are printed, the first grid line and the second grid line are dried and cured together, drying equipment used after the first grid line is printed can be directly saved, the equipment investment and the operation time are reduced, the production efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to a solar cell, its printing process, printing production line, and photovoltaic module. Background Technology

[0002] Cell printing refers to the printing of grid lines in a solar cell, and grid line printing is one of the key steps in the manufacturing of solar cells.

[0003] In related technologies, the printing of grid lines in solar cells generally involves first using laser transfer to transfer the printed electrode material onto the solar cell substrate, followed by drying and curing to obtain grid lines in one direction. Then, screen printing is used to print the electrode material onto the solar cell substrate, followed by drying and curing again to obtain grid lines in another direction, thus completing the printing of grid lines in the solar cell.

[0004] It is evident that the grid line printing process in related technologies requires drying after laser transfer and after screen printing, which affects production costs and efficiency. Summary of the Invention

[0005] This application provides a cell printing process to solve the technical problem in the related art where the grid line printing method of cell affects production cost and production efficiency.

[0006] To address the above problems, this application provides a cell printing process, the cell printing process comprising:

[0007] Provide battery cells;

[0008] Printing the battery cell includes: printing the battery cell using a first printing method to generate a first grid line; and printing the battery cell using a second printing method to generate a second grid line, wherein the second grid line intersects with the first grid line.

[0009] The battery cell is dried, and the first grid line and the second grid line are dried together and formed into one piece.

[0010] In some embodiments, the first printing method includes screen printing.

[0011] In some embodiments, the second printing method includes transfer printing.

[0012] In some embodiments, the printing of the battery cell using the first printing method also generates mark points.

[0013] In some embodiments, printing the battery cell using the second printing method includes: determining the printing position of the second grid line based on the mark point.

[0014] In some embodiments, drying the battery cells includes drying the battery at a drying temperature of 150°C to 160°C for 2 to 5 minutes.

[0015] In some embodiments, at the intersection of the first gate line and the second gate line, the second gate line covers the first gate line in the width direction of the first gate line.

[0016] This application also provides a battery cell printing production line for any of the battery cell printing processes described above, comprising:

[0017] The printing station includes a first printing device and a second printing device connected sequentially along the transport direction of the battery cells. The first printing device is used to print the battery cells according to a first printing method; the second printing device is used to print the battery cells according to a second printing method.

[0018] A drying station is used to dry the battery cells, and the printing station and the drying station are connected sequentially along the transport direction of the battery cells.

[0019] This application also provides a battery cell having intersecting main grid and sub-grid, wherein the main grid and the sub-grid are integrally formed at the intersection of the main grid and the sub-grid, and the sub-grid is continuous and covers the main grid in the width direction of the main grid.

[0020] This application also provides a photovoltaic module, including the solar cells described above.

[0021] The beneficial effects of the embodiments of this application are as follows: The battery cell printing process provided by this application, by printing the first grid line and the second grid line of the battery cell first, and then drying the first grid line and the second grid line together after printing, can save the drying equipment after printing the first grid line, reduce equipment investment and operating time, improve production efficiency, and reduce production costs. In addition, before drying the battery cell, the first grid line and the second grid line printed on the battery cell are in a fluid state with a certain degree of fluidity. The paste of the first grid line and the paste of the second grid line are fused at the contact point. After drying, the first grid line and the second grid line become one, which makes it easier for the grid lines in the battery cell to collect current, improve the electrical performance of the battery cell, and at the intersection of the first grid line and the second grid line, the second grid line can smoothly transition without interruption, while reducing the use of paste.

[0022] When printing the second grid line, the mark points in the first grid line screen printing are used as positioning points to locate the printing position of the second grid line. Since screen printing is a contact printing method and laser transfer is a non-contact printing method, the positioning accuracy of the mark points in screen printing is high, which effectively improves the transfer accuracy of the second grid line. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0024] Figure 1 This is a flowchart of a battery cell printing process provided in one embodiment of this application;

[0025] Figure 2 This is a schematic diagram of the structure at the intersection of the first and second gate lines according to an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of the structure at the intersection of the first and second gate lines in the related technology;

[0027] Figure 4 This is the dried image of the intersection of the first and second grid lines in the related technology;

[0028] Figure 5 This is an image of the intersection of the first and second grid lines provided in one embodiment of this application after drying;

[0029] Figure 6 This is a comparison chart of the laser transfer mode efficiency of an embodiment of this application and the laser transfer mode efficiency in related technologies;

[0030] Figure 7 This is a comparison diagram of the wet weight of the battery cell in one embodiment of this application and the wet weight of the battery cell in related technologies;

[0031] Figure 8 This is a schematic diagram of the structure of the grid lines generated by laser transfer;

[0032] Figure 9 This is a schematic diagram of the structure of a battery cell printing production line provided in one embodiment of this application.

[0033] In the diagram: 100, first printing equipment; 200, second printing equipment; 300, drying equipment; 400, conveying equipment. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0035] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0036] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0037] Please see Figure 1 This application provides a cell printing process that can be used for printing grid lines in photovoltaic cells. The cell printing process specifically includes the following steps:

[0038] Step S10: Provide the battery cell.

[0039] The specific type of solar cell in this application embodiment is not limited. For example, it can be a heterojunction solar cell, a TOPCON (Tunnel Oxide Passivated Contact) solar cell, or a PERC (Passivated Emitter and Rear Cell) solar cell, but it is not limited to these. It should be noted that the solar cell has electrodes, and the grid lines in the solar cell are connected to the electrodes, thereby allowing the collected current to be output. It is understood that the solar cell provided before printing is a solar cell with electrodes.

[0040] Step S20 involves printing on the battery cell, including: Step S21, printing on the battery cell using a first printing method to generate a first grid line; Step S22, printing on the battery cell using a second printing method to generate a second grid line; wherein the first grid line and the second grid line intersect.

[0041] When printing the first grid line, it is connected to the electrode in the solar cell. For example, the first grid line can be a main grid or a pseudo-main grid. Correspondingly, the second grid line is a sub-grid, also called a fine grid. The first and second grid lines intersect, so that the first grid line can collect the current from the second grid line. For example, the extension directions of the first and second grid lines can be perpendicular to each other.

[0042] In some embodiments, the first printing method may include screen printing, such as silkscreen printing or stencil printing. The second printing method may include transfer printing, such as laser transfer printing, but is not limited thereto.

[0043] Step S30: Dry the battery cell, wherein the first grid line and the second grid line are dried together and formed into one piece.

[0044] The specific parameters for drying the solar cells can be set according to the production scale. For example, in some embodiments, a drying temperature of 150℃-160℃ can be used to dry the solar cells for 2-5 minutes. In related technologies, the two drying processes typically involve drying the solar cells at 150℃-160℃ for 2-5 minutes each time. Therefore, the solution in this application significantly shortens the printing process time and reduces energy consumption.

[0045] After the first and second grid lines are printed, the solar cells enter the drying equipment for drying. At this time, the first and second grid lines are dried together in the drying equipment. In contrast, related technologies perform drying once after laser transfer printing and once after screen printing, which is equivalent to two drying processes. Obviously, compared with the solution of this application, the solution of this application can save the drying equipment after printing the first grid line, while reducing equipment investment and operation time, improving production efficiency, and reducing production costs.

[0046] It should be noted that in related technologies, the solar cell is dried after the first grid line is printed, and then the second grid line is printed. During the printing of the second grid line, at the intersection of the first and second grid lines, the second grid line overlaps with the already dried first grid line. When the second grid line is dried again, cracking is likely to occur at the intersection. Figure 3 and 4As shown. In this application, the first grid line is printed, followed by the printing of the second grid line. Then, the first and second grid lines are dried together. Before drying the cell, the pastes for both the first and second grid lines are in a semi-fluid state. At the contact points between the first and second grid lines, the pastes fuse together. Therefore, after drying, the first and second grid lines form a single unit, and the second grid line can smoothly transition without interruption, facilitating current collection in the cell and improving the electrical performance of the cell. Figure 2 and 5 As shown. In addition, it should be noted that the volume of the first grid line increases after drying, and the second grid line overlaps with the dried first grid line. Compared with the second grid line overlapping the undried first grid line, this effectively saves slurry on the second grid line.

[0047] like Figure 6 and Figure 7 As shown in the figures, "two-stage drying after laser transfer" refers to the related technology where, in cell printing, the sub-grid is first printed via laser transfer and then dried, followed by the main grid printing via screen printing and then dried. "One-stage drying after laser transfer" refers to the solution in this application where the main grid or pseudo-main grid is first printed via screen printing, then the sub-grid is printed via laser transfer, and finally both the main and sub-grids are dried together. "Difference" represents the difference in efficiency between the two laser transfer modes. As can be seen from these two figures, the solution in this application can also improve laser transfer efficiency, obtain a second grid line with a larger aspect ratio, reduce paste usage, achieve the effects of reducing production costs and improving resource utilization, and also reduce the area of ​​the cell covered.

[0048] like Figure 2 and Figure 5 As shown, in some embodiments, at the intersection of the first and second grid lines, the second grid line covers the first grid line in the width direction of the first grid line. That is, when printing the second grid line, it is directly overlapped with the first grid line at the intersection. In this way, since the first and second grid lines become integrated after the cell is dried, the aspect ratio of the second grid line is significantly increased at the intersection, resulting in a grid line morphology with a larger aspect ratio, which facilitates current collection and reduces resistance. Compared to the separate drying of the main and sub-grids in related technologies, the solution in this application achieves the fusion of the first and second grid lines, rather than simply a height superposition.

[0049] In some embodiments, a mark point is also generated in step S21.

[0050] When the first printing method is screen printing, that is, printing the first grid line using a screen, it's understandable that to generate the first grid line and mark points on the battery cell using screen printing, it's necessary to first create mark points on the screen. For example, mark points are designed at designated locations on the screen for easy camera recognition. Generally, one screen pattern corresponds to the four corner areas for mark points. These mark points can be dots, rings, squares, rhombuses, etc., but are not limited to these. The screen pattern is the printed pattern corresponding to the first grid line.

[0051] In some embodiments, step S22 includes locating the printing position of the second gate line based on the mark point generated in step S21.

[0052] It should be noted that when the second printing is laser transfer printing, because laser transfer printing is a non-contact printing process, the laser propels the ink attached to the transfer mold groove onto the solar cell. There is a certain vertical distance between the transfer mold and the solar cell, and the relative position of the ink and the solar cell may shift during the falling process. For example, ... Figure 8 As shown, the second grid line printed by laser transfer is not a straight line. Therefore, if the mark points transferred to the solar cell are used as the positioning points for the second grid line during the laser transfer printing process, the mark points may shift during the transfer process, affecting the positioning accuracy of the second grid line. The screen printing method in the first printing method is a contact printing method, which ensures the printing accuracy of the mark points. Thus, using the screen-printed mark points as positioning points for the second grid line improves the positioning accuracy of the laser transfer printed second grid line. Through multiple experiments, if the transferred mark points are used as the laser transfer printed second grid line, the positioning accuracy of the second grid line is generally above ±25µm, while using the screen-printed mark points as the laser transfer printed second grid line, the positioning accuracy can be controlled below ±10µm. As can be seen, in some embodiments, when the first printing method is screen printing and the second printing method is laser transfer printing, the first screen prints mark points and the first grid line, and then when the second grid line is laser transferred printed, the mark points printed on the screen are used as the printing positioning points of the second grid line, which can effectively improve the positioning accuracy of the second grid line printing.

[0053] When using the mark points of screen printing as the printing positioning points for laser transfer, the CCD camera in the laser transfer equipment first identifies the mark points of the previous printing, then positions the screen-printed graphic based on the mark points, and then overlays the transferred graphic according to the screen-printed graphic, thus completing the positioning printing of the second grid line. It can be understood that the transferred graphic is the printed graphic corresponding to the second grid line.

[0054] like Figure 9As shown, in some embodiments, this application also provides a battery cell printing production line for any of the battery cell printing processes described above. The battery cell printing production line includes a printing station and a drying station. The printing station includes a first printing device 100 and a second printing device 200 connected sequentially along the battery cell transport direction. The first printing device 100 is used to print on the battery cell according to a first printing method; the second printing device 200 is used to print on the battery cell according to a second printing method. The drying station is used to dry the battery cell, and the printing station and the drying station are connected sequentially along the battery cell transport direction.

[0055] For example, in some embodiments, the first printing method is screen printing, and the second printing method is laser transfer printing. Correspondingly, at the printing station, the first printing equipment 100 is a screen printing equipment, and the second printing equipment 200 is a laser transfer printing equipment. It can be understood that to achieve the transfer of the battery cells between the first printing equipment 100 and the second printing equipment 200, the two equipments are connected by a transmission device. This application embodiment does not limit the specific structure of the transmission device 400. Since the first grid line and the second grid line extend in different directions, it can be understood that the transmission device has a functional mechanism for steering the battery cells. The drying equipment 300 can be connected after the second printing equipment via the transmission device 400.

[0056] The battery cell printing production line provided in this application is used to print battery cells according to the battery cell printing process in the above embodiments. Therefore, it has at least all the beneficial effects brought about by the technical solutions of the above battery cell printing process embodiments, which will not be repeated here.

[0057] In some embodiments, this application also provides a battery cell having intersecting main grids and sub-grids, wherein the main grids and sub-grids are integrally formed at the intersection of the main grids and the sub-grids, and the sub-grids are continuous and cover the main grids in the width direction of the main grids.

[0058] It should be noted that the main grid in a solar cell refers to the grid lines that connect the electrodes in the solar cell, and it also includes pseudo grids.

[0059] In a solar cell, the main busbar and the sub-busbar are integrated at their intersection, such as... Figure 5 As shown, at the point where the main grid and the auxiliary grid come into contact, the slurry of the main grid and the auxiliary grid are fused together, so that after drying, the main grid and the auxiliary grid become one.

[0060] like Figure 2 As shown, the secondary gate is continuous with and covers the primary gate in the width direction of the primary gate, meaning the secondary gate overlaps the primary gate. Since the primary and secondary gates are still integrated at the intersection, the aspect ratio of the secondary gate is significantly increased, resulting in a gate line morphology with a larger aspect ratio, which facilitates current collection and reduces resistance.

[0061] In some embodiments, this application also provides a photovoltaic module, including the solar cells described in the above embodiments.

[0062] It is understood that the solar cells and photovoltaic modules provided in this application have at least all the beneficial effects brought about by the technical solutions of the above-described embodiments of the solar cell printing process, which will not be elaborated here.

[0063] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A battery cell printing process, characterized in that, The battery piece printing process comprises: providing a battery piece; printing the battery piece, comprising: printing the battery piece by a first printing method to generate a first grid line; printing the battery piece by a second printing method to generate a second grid line, the second grid line intersecting the first grid line; drying the battery piece, the first grid line and the second grid line being dried together and integrated.

2. The cell printing process of claim 1, wherein, The first printing method comprises screen printing.

3. The cell printing process of claim 2, wherein, The second printing method comprises transfer printing.

4. The cell printing process of any one of claims 1-3, wherein, The printing of the battery piece by the first printing method also generates mark points.

5. The cell printing process of claim 4, wherein, The printing of the battery piece by the second printing method comprises positioning the printing position of the second grid line according to the mark points.

6. The cell printing process of claim 1, wherein, The drying of the battery piece comprises drying the battery piece at a drying temperature of 150-160°C for 2-5 minutes.

7. The cell printing process of claim 1, wherein, At the intersection of the first grid line and the second grid line, the second grid line covers the first grid line in the width direction of the first grid line.

8. A cell printing line, characterized in that, The battery piece printing process of any one of claims 1-7 comprises: a printing station comprising a first printing device and a second printing device connected in sequence along the transmission direction of the battery piece, the first printing device being configured to print the battery piece by a first printing method; the second printing device being configured to print the battery piece by a second printing method; a drying station configured to dry the battery piece, and the printing station and the drying station being connected in sequence along the transmission direction of the battery piece.

9. A battery sheet, characterized by The battery piece has intersecting main grid lines and auxiliary grid lines, at the intersection of the main grid lines and the auxiliary grid lines, the main grid lines and the auxiliary grid lines are integrated, and in the width direction of the main grid lines, the auxiliary grid lines are continuous and cover the main grid lines.

10. A photovoltaic module, characterized by, The battery piece of claim 9 is provided.

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