Method for manufacturing solar cell grid lines

Abstract

The application provides a preparation method of a solar cell grid line, including: a cell piece precursor has a to-be-slotted film layer, a plurality of to-be-slotted areas in the to-be-slotted film layer are arranged at intervals of a respective center line distance D; a laser transfer carrier plate includes a plurality of first transfer areas arranged at intervals of a distance k, k is equal to D-d, k>0, each first transfer area has a guide plate part and a filling groove which are connected and have a same width d; the center line of one guide plate part is aligned with the center line of one to-be-slotted area; laser slotting, a first laser beam emitted by a laser passes through the guide plate part to slot the to-be-slotted area to form a slot with a width of d in the to-be-slotted film layer; grid line transfer, the laser transfer carrier plate is moved horizontally along a first direction by a distance d, slurry in the filling groove is transferred to the slot by laser transfer, one grid line transfer is completed, and the laser is moved horizontally along a second direction by a distance D; the steps of laser slotting and grid line transfer are repeated. The method reduces cell surface damage and recombination, reduces cost, and improves solar cell efficiency.

Description

Technical Field

[0001] This application relates to the field of solar cell fabrication technology, and in particular to a method for fabricating solar cell grid lines. Background Technology

[0002] Before laser transfer printing is used to fabricate grid lines on the cell precursor, a grooved area is usually formed on the surface of the cell precursor. Then, grid lines can be formed in the grooved area using laser transfer technology. However, this often makes it difficult to ensure that the grooved area and the grid line paste are aligned while reducing the width of the grooved area and the amount of paste used. This makes it difficult to further improve the efficiency of solar cells, reduce the manufacturing cost of solar cells, and improve the manufacturing efficiency of solar cells.

[0003] Therefore, a new method for fabricating solar cell grid lines is urgently needed. Summary of the Invention

[0004] This application provides a method for fabricating a solar cell grid line, including:

[0005] A cell precursor with a grooving film layer is provided, the grooving film layer including a grooving area for forming grid lines, and a plurality of grooving areas are arranged at intervals of D with their respective center line spacing.

[0006] A laser transfer substrate is provided, which includes a plurality of first transfer areas arranged at intervals of k, where k equals Dd and k>0. Each first transfer area has a guide plate portion and a filling groove that are connected and have a width of d. The filling groove is filled with paste and is raised relative to the plane of the guide plate portion.

[0007] Align the center line of a guide plate with the center line of an area to be slotted.

[0008] Laser grooving: The first laser beam emitted by the laser is used to groove the area to be grooved through the guide plate to form a groove with a width of d in the film layer to be grooved. In the laser emission direction, the front body of the solar cell and the laser transfer carrier are arranged parallel to each other at intervals.

[0009] For grid line transfer, the laser transfer plate is moved horizontally a distance d along the first direction to make the filling groove correspond to the groove opening. The paste in the filling groove is transferred to the groove opening by laser to complete one grid line transfer. The laser is then moved horizontally a distance D along the second direction.

[0010] Repeat the laser grooving and grid line transfer steps until all grid lines corresponding to the grooving areas in the grooving film layer of the cell precursor are fabricated. The second direction is opposite to the first direction and is perpendicular to the laser emission direction.

[0011] The solar cell grid line fabrication method provided in this application is based on the distance D between the areas to be grooved on the cell precursor (i.e., the distance relationship between the preset grid lines of the solar cell). It is combined with a laser transfer carrier plate (including a guide plate and a filling groove) with a first transfer area. Furthermore, the coordination of the laser transfer carrier plate and the laser in the laser grooving and grid line transfer steps in terms of movement direction and distance ensures that the groove opening is aligned with the paste used to form the grid lines, while also ensuring the consistency between the grooving width and the width of the transferred grid lines. This reduces surface damage to the cell, reduces recombination, improves solar cell efficiency, saves on the amount of paste used to make the grid lines, reduces cell manufacturing costs, and improves solar cell performance. The solar cell grid line fabrication method provided in this application also ensures that the laser grooving and grid line laser transfer steps are completed in the same laser equipment, reducing the investment cost of production equipment. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0013] Figure 1 This is a schematic diagram of a laser transfer substrate according to an embodiment of the method for fabricating solar cell grid lines provided in this application;

[0014] Figure 2 This is a schematic diagram of step S30 in an embodiment of the method for fabricating solar cell grid lines provided in this application;

[0015] Figure 3 This is a schematic diagram of step S40 in an embodiment of the method for fabricating solar cell grid lines provided in this application;

[0016] Figure 4 This is a schematic diagram of step S50 in an embodiment of the method for fabricating solar cell grid lines provided in this application, showing the operation of the filling groove corresponding to the groove opening and the laser acting on the slurry in the filling groove;

[0017] Figure 5 This is a schematic diagram of step S50 in an embodiment of the solar cell grid line fabrication method provided in this application, in which the slurry in the filling tank is transferred to the opening of the tank by laser to complete the transfer of one grid line;

[0018] Figure 6 This is a schematic diagram of the operation of horizontally moving the laser a distance D along the second direction in step S50 of an embodiment of the method for fabricating solar cell grid lines provided in this application;

[0019] Figure 7 This is another schematic diagram of the structure of the laser transfer substrate in one embodiment of the method for fabricating solar cell grid lines provided in this application;

[0020] Figure 8 This is a schematic diagram of another structure of a laser transfer substrate in one embodiment of the method for fabricating solar cell grid lines provided in this application;

[0021] Figure 9 This is a schematic diagram of another structure of a laser transfer substrate in one embodiment of the method for fabricating solar cell grid lines provided in this application;

[0022] Figure 10 This is a schematic diagram of the structure of a laser transfer substrate in another embodiment of the method for fabricating solar cell grid lines provided in this application;

[0023] Figure 11 This is a flowchart illustrating steps S10' to S40' of another embodiment of the method for fabricating solar cell grid lines provided in this application;

[0024] Figure 12 This is a flowchart illustrating steps S50' to S80' of another embodiment of the method for fabricating solar cell grid lines provided in this application;

[0025] Figure 13 This is a three-dimensional structural schematic diagram of a laser transfer substrate according to another embodiment of the method for fabricating solar cell grid lines provided in this application;

[0026] Figure 14 This is another three-dimensional structural schematic diagram of a laser transfer substrate according to another embodiment of the method for fabricating solar cell grid lines provided in this application;

[0027] Figure 15 This is a schematic diagram of a grid line arrangement structure of a solar cell prepared using the solar cell grid line preparation method provided in this application;

[0028] Figure 16 This is a schematic diagram of another grid line arrangement structure of a solar cell prepared using the solar cell grid line preparation method provided in this application.

[0029] Explanation of reference numerals in the attached figures:

[0030] 10-Laser transfer substrate; 11-Guide plate section; 12-Filling groove;

[0031] 20-Slurry; 21-Grid line; 30-Battery substrate; 31-Film layer to be grooved; 311-Groove opening; 40-Laser;

[0032] 50-laser.

[0033] X - First direction; Y - Second direction; Z - Laser emission direction;

[0034] A-First transfer area;

[0035] B - Second transfer area; 60 - Positioning part; 61 - Limiting groove; Connecting plate part - 62; Laser protective layer - 63. Detailed Implementation

[0036] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and 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. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0040] The inventors, through long-term research on methods for fabricating solar cell grid lines, discovered that when using laser transfer printing to fabricate grid lines, it is often necessary to first laser-groove the cell substrate to form a fixed laser-grooved pattern, and then fabricate the grid lines on this fixed pattern using pattern transfer printing (PTP) technology. Generally, the laser grooving and pattern transfer steps need to be completed in different laser devices, resulting in high investment in production line equipment and high production costs.

[0041] Laser pattern transfer (PPT) is a material deposition technique. It typically uses a transparent film made of amorphous polyethylene terephthalate (APET) as a carrier substrate. A rigid metal die with a pattern is used to imprint the desired trench geometry onto the carrier film. The film is collected on rollers and then mounted in a PPT machine. Two metal blades are used to fill the trenches with paste (e.g., silver paste, aluminum paste) to form a laser transfer substrate. A laser is then used to transfer the paste from the laser transfer substrate onto the target solar cell precursor.

[0042] In the process of fabricating solar cell grids using laser pattern transfer, laser grooving is first performed, followed by laser transfer of grid lines onto a fixed laser-grooved pattern. Machine vision positioning is required before grid line printing. Two methods are generally used to meet the alignment and matching requirements between the groove opening and the transferred grid lines in solar cells. The first method increases the groove opening width, making it much larger than the width of the transferred grid lines to achieve alignment. This method often results in a larger damaged area in the grooving film, leading to poorer passivation of the cell surface and a lower open-circuit voltage. The second method keeps the groove opening width constant while increasing the width of the transferred grid lines. This method increases the amount of paste used, thus increasing the cost of grid line fabrication. It also increases shading on the solar cell surface, reducing the light-receiving area and lowering the short-circuit current.

[0043] To further improve solar cell efficiency and reduce paste usage, the most effective method is to make the width of the laser-grooved area comparable to the width of the transferred grid lines. However, during the process of laser transfer fabrication of grid lines on the cell precursor, it is often difficult to ensure that the grooved area and the grid line paste are aligned while simultaneously reducing the width of the grooved area and the amount of paste used. This makes it difficult to further improve solar cell efficiency, reduce manufacturing costs, and enhance overall manufacturing efficiency.

[0044] This application is made in light of the discovery and research into the aforementioned technical problems.

[0045] like Figures 1 to 6 As shown, this application embodiment provides a method for fabricating a solar cell grid line 21, including:

[0046] S10: Provide a cell precursor with a grooving film layer 31, the grooving film layer 31 including a grooving area for forming grid lines 21, and a plurality of grooving areas are arranged at intervals of D with their respective center line spacing.

[0047] S20: Provide a laser transfer substrate 10. The laser transfer substrate 10 includes a plurality of first transfer areas A arranged at intervals of K, where k equals Dd and k>0. Each first transfer area A has a guide plate portion 11 that is connected and has a width of d and a filling groove 12. The filling groove 12 is filled with paste 20 and is raised relative to the plane of the guide plate portion 11.

[0048] S30: Align the center line of a guide plate portion 11 with the center line of a grooving area;

[0049] S40: Laser grooving, the laser 50 emitted by the laser 40 (this step emits the first laser beam) grooves the area to be grooved through the guide plate 11 to form a groove 311 with a width of d in the film layer 31 to be grooved. In the laser emission direction Z, the front body of the battery cell and the laser transfer carrier plate 10 are arranged parallel to each other at intervals.

[0050] S50: Transfer of grid line 21, move the laser transfer plate 10 horizontally along the first direction X by a distance d, so that the filling groove 12 corresponds to the groove opening 311, use laser 50 to transfer the paste 20 in the filling groove 12 to the groove opening 311, and complete the transfer of one grid line 21. Move the laser 40 horizontally along the second direction Y by a distance D.

[0051] Repeat the steps of laser grooving and grid line 21 transfer until all grid lines 21 corresponding to the grooving areas in the grooving film layer 31 of the cell precursor are fabricated. The second direction Y is opposite to the first direction X and is perpendicular to the laser emission direction Z.

[0052] like Figures 1 to 6 As shown, the centerline of the guide plate portion 11 is a thin dashed line perpendicular to the plane where the guide plate portion 11 is located, and the two ends of the guide plate portion 11 in the width direction are equidistant from the centerline of the guide plate portion 11. The centerline of the filling groove 12 is a thin dashed line perpendicular to the plane where the guide plate portion 11 is located, and the two ends of the filling groove 12 in the width direction are equidistant from the centerline of the filling groove 12. The distance between the centerline of the guide plate portion 11 and the centerline of the filling groove 12 is d. The width of the area to be grooved is equal to the width of the groove opening 311 after laser grooving. In the solar cell gate fabrication process, the centerline of the area to be grooved is a thick dashed line perpendicular to the plane where the film layer 31 to be grooved and the guide plate portion 11 are located, and the two ends of the area to be grooved in the width direction are equidistant from the centerline of the area to be grooved.

[0053] The solar cell grid fabrication method provided in this application embodiment allows the laser transfer substrate 10 to move a distance d each time and complete the transfer of one grid line 21. In the second direction Y of the laser 40 movement, the area to be slotted adjacent to the grid line 21 is opposite to the guide plate of the laser transfer substrate 10, so that the grid line 21 transfer and laser slotting steps can be connected to each other, thereby improving the efficiency of grid line 21 fabrication.

[0054] In the method for preparing solar cell grid lines 21 provided in this application embodiment, the design is based on the distance D between the areas to be grooved on the cell precursor (i.e., the distance relationship between the preset grid lines 21 of the solar cell). Simultaneously, a laser transfer carrier plate 10 with a first transfer area A (including a guide plate portion 11 and a filling groove 12, both with a width of d) is designed. Furthermore, the coordination of the laser transfer carrier plate 10 and the laser 40 in the direction and distance of movement during the laser grooving and grid line 21 transfer steps ensures that the groove opening 311 is aligned with the paste 20 used to form the grid lines 21, while also ensuring the consistency between the grooving width and the width of the transferred grid lines 21. This reduces surface damage to the cell, reduces surface recombination, improves solar cell efficiency, saves the amount of paste 20 used to make the grid lines 21, and reduces the cell manufacturing cost. A reduced width of the transferred grid lines 21 increases the light-receiving area of ​​the cell, increasing the short-circuit current and improving the solar cell efficiency. The method for preparing solar cell grid lines 21 provided in this application embodiment can also ensure that the two steps of laser grooving and grid line 21 transfer are completed in the same laser equipment, thereby reducing the cost of production equipment.

[0055] In some optional embodiments of this application, the width of the filling groove 12 refers to the width of the slotted port of the filling groove 12 on the plane where the guide plate portion 11 is located.

[0056] In some optional embodiments of this application, the cell precursor includes a cell substrate 30 and a trenching layer 31 disposed on at least one side of the silicon substrate. In some examples of these embodiments, the trenching layer 31 is a passivation layer of the solar cell. In some examples, the cell substrate 30 includes a silicon substrate and an emitter, wherein the silicon substrate is monocrystalline silicon, polycrystalline silicon, microcrystalline silicon, or amorphous silicon, and the emitter is a silicon material with a doping type opposite to that of the silicon substrate. In some examples, the trenching layer includes at least one of silicon nitride, aluminum oxide, silicon oxynitride, silicon oxide, and aluminum nitride.

[0057] In some optional embodiments of this application, in the step of aligning the center line of a guide plate portion 11 with the center line of a grooved area, the center line of the guide plate portion 11 closest to its own first side of the laser transfer substrate 10 corresponds to the center line of the grooved area of ​​the battery cell front body closest to its own second side, wherein the first side and the second side belong to the same side.

[0058] In some optional embodiments of this application, in the laser grooving step, the laser 50 emitted by the laser 40 (emitting a first laser beam) grooves the area to be grooved via the guide plate 11. That is, the laser 50 grooves the area to be grooved based on the position and width of the guide plate 11. Since the width of both the guide plate 11 and the filling groove 12 is d, a groove with a width of d is formed by the laser 50 grooving with the guide plate 11 as a reference. Furthermore, the width of the filling groove 12 is d, thus making the width of the transferred grid line 21 equal to the width of the grooving.

[0059] like Figure 7 As shown, in some optional embodiments of this application, the step of providing the laser transfer substrate 10 further includes:

[0060] The second transfer area B is located between two adjacent first transfer areas A and is connected to the first transfer area A. The second transfer area B has a positioning part 60. The positioning part 60 is disposed opposite to the filling groove 12 on both sides of the guide plate part 11 and is connected to the guide plate part 11. The positioning part 60 is used to assist the laser 50 in alignment and to prevent the laser 50 from acting on the non-grooving area of ​​the film layer 31 to be grooved.

[0061] In some optional embodiments of this application, step S30 of aligning the center line of a guide plate portion 11 with the center line of a region to be slotted includes:

[0062] Step S31: Set reference marks on both sides of the area to be slotted, and obtain the position information of the area to be slotted based on the reference marks. In some examples, multiple laser mapping system cameras are used to obtain the position information of the reference marks by taking pictures, and the position information of the reference marks is sent to the controller.

[0063] Step S32: Based on the position information of the area to be grooved, control the laser 40 to move relative to the cell front body until the second laser beam emitted by the laser 40 covers an area to be grooved, completing the alignment of the laser 40 with an area to be grooved in the cell front body. The beam widths of the first laser beam (laser 50 emitted by the emitter for grooving) and the second laser beam are equal to the width of the area to be grooved. The power of the first laser beam is greater than the power of the second laser beam, and the second laser beam does not act on the film layer 31 to be grooved. In these examples, the first laser beam can act on the film layer 31 to be grooved, that is, when the first laser beam with a higher energy density irradiates the film layer 31 to be grooved, the film layer 31 to be grooved can absorb the energy of the first laser beam, thereby producing melting, ablation, and evaporation, thereby achieving the purpose of removing the film layer. In step S40, the laser emitter emits the first laser beam. The second laser beam does not act on the film layer to be grooved, that is, the energy density of the second laser beam is lower than the energy density of the first laser beam, and the area of ​​the film layer to be grooved irradiated by the second laser beam will not experience thinning or even perforation. The parameters of the first laser beam and the second laser beam can be set according to the specific material and thickness of the film layer to be grooved. In step S30, the laser emits the second laser beam.

[0064] Step S33: Position a guide plate portion 11 in the laser transfer carrier plate between the laser 40 and the cell precursor (including the cell substrate 30 and the grooving film layer 31). Simultaneously, the second laser beam emitted by the laser 40 exits through the laser transfer carrier plate 10. Based on the laser transmittance of the area above the grooving area aligned with the laser 40 and / or the laser reflectivity between the laser transfer carrier plate 10 and the laser 40, control the laser transfer carrier plate 10 to move relative to the cell precursor until the center line of the guide plate portion 11 is aligned with the center line of the grooving area.

[0065] In some optional embodiments of this application, the second transfer area B further includes a connecting plate portion 62, which connects the positioning portion 60 to the filling groove 12 in the adjacent first transfer area A.

[0066] Please refer to Figure 7 In some optional embodiments of this application, the positioning portion 60 may include a laser protection material. The laser protection material is a material with low transmittance and thermal stability to the laser 50 used for laser grooving, and it hinders the propagation of the laser beam. In some examples of these embodiments, nitrogen-aluminum co-doped hydrophobic carbon dots for laser 50 protection are doped into a transparent film made of amorphous polyethylene terephthalate. In other examples of these embodiments, the positioning portion 60 is formed from a polymethyl methacrylate film doped with nitrogen-aluminum co-doped hydrophobic carbon dots. The positioning portion 60 is connected to the connecting plate portion 62 in the second transfer area B.

[0067] In the above embodiments, the positioning part 60 prevents the second laser beam from passing through the laser transfer carrier plate 10, and the filling groove 12 is filled with paste 20, which also prevents the second laser beam from passing through the laser transfer carrier plate 10. Therefore, in these embodiments, step S33: a guide plate part 11 in the laser transfer carrier plate is positioned between the laser 40 and the cell precursor (including the cell substrate 30 and the film layer 31 to be grooved), while the second laser beam emitted by the laser 40 is emitted through the laser transfer carrier plate 10. The laser transfer carrier plate 10 is moved relative to the cell precursor according to the laser transmittance of the area above the area to be grooved that is aligned with the laser 40, until the center line of the guide plate part 11 is aligned with the center line of the area to be grooved. When the center line of the guide plate portion 11 in the laser transfer carrier 10 is not aligned with the center line of a grooving area, the second laser beam is at least partially blocked by the obstruction of the positioning portion 60 and the filling groove 12 and fails to pass through the guide plate portion 11 to the area above the grooving area aligned with the laser 40. Therefore, the transmittance of the second laser is reduced. When the transmittance of the second laser is not affected, it means that the center line of the guide plate portion 11 is aligned with the center line of a grooving area.

[0068] like Figure 8 As shown, in some optional embodiments of this application, the positioning part 60 includes a laser protective layer 63 covering the substrate of the laser transfer carrier 10. In some examples of these embodiments, the substrate of the laser transfer carrier 10 is formed of a transparent film made of amorphous polyethylene terephthalate, and the laser protective layer 63 has the effect of absorbing or reflecting the laser beam, especially the first laser beam 50 used for laser grooving, so as to block the first laser beam 50 on the laser protective layer 63 and prevent the first laser beam 50 from further propagating downward and causing damage to the non-grooving area of ​​the film layer 31 to be grooved.

[0069] In some examples of the above embodiments, the material of the laser protective layer 63 includes any one of indanthrin-based compounds, C60-based compounds, metal phthalocyanine organic materials, zinc selenide, aluminum, silver, SiO2, TiO2, Al2O3, Ta2O5, MgF2, LaF3, and AlF3.

[0070] In the above embodiments, when the laser protective layer 63 of the positioning part 60 absorbs the laser beam, before the center line of the guide plate part 11 is aligned with the center line of the area to be slotted, the positioning part 60 prevents the laser beam from passing through the laser transfer carrier plate 10. The filling groove 12 is filled with paste 20, and the filling groove 12 also prevents the laser beam from passing through the laser transfer carrier plate 10. Therefore, in these embodiments, step S33: the guide plate part 11 in the laser transfer carrier plate is positioned between the laser 40 and the battery cell precursor (including the battery substrate 30 and the film layer 31 to be slotted), and the laser beam emitted by the laser 40 is emitted through the laser transfer carrier plate 10. The laser transfer carrier plate 10 is moved relative to the battery cell precursor according to the laser transmittance of the area above the area to be slotted that is aligned with the laser 40, until the center line of the guide plate part 11 is aligned with the center line of the area to be slotted.

[0071] In the above embodiments, when the laser protective layer 63 of the positioning part 60 reflects the laser beam 50, before the center line of the guide plate part 11 is aligned with the center line of the area to be slotted, the positioning part 60 prevents the laser beam from passing through the laser transfer carrier plate 10 and reflects the laser beam. The filling groove 12 is filled with slurry 20, and the filling groove 12 also prevents the laser beam from passing through the laser transfer carrier plate 10. Therefore, in these embodiments, step S33: the guide plate part 11 in the laser transfer carrier plate is positioned between the laser 40 and the cell precursor (including the cell substrate 30 and the film layer 31 to be slotted), and the laser beam emitted by the laser 40 is emitted through the laser transfer carrier plate 10. The laser transfer carrier plate 10 is moved relative to the cell precursor according to the laser transmittance of the area above the area to be slotted aligned with the laser 40 and / or the laser reflectance between the laser transfer carrier plate and the laser, until the center line of the guide plate part 11 is aligned with the center line of the area to be slotted.

[0072] like Figure 9 As shown, in some optional embodiments of this application, the positioning part 60 includes a limiting groove 61, which protrudes from the guide plate part 11, and the protruding surface of the limiting groove 61 is covered with a laser reflective layer. The laser reflective layer includes at least one of aluminum, silver, gold, and copper, and the laser reflective layer is a thin metal layer.

[0073] In the above embodiment, when the laser reflective layer of the positioning part 60 has a reflective effect on the laser beam 50, before the center line of the guide plate part 11 is aligned with the center line of the area to be slotted, the positioning part 60 prevents the laser beam from passing through the laser transfer carrier plate 10. Due to the protrusion of the limiting groove 61, the incident laser is reflected at a certain angle to the side of the laser 50 emission area from the horizontal plane where the guide plate part 11 is located. The filling groove 12 is filled with paste 20, and the filling groove 12 prevents the laser beam from passing through the laser transfer carrier plate 10. Therefore, in these embodiments, step S33 involves positioning a guide plate portion 11 of the laser transfer carrier between the laser 40 and the cell precursor (including the cell substrate 30 and the grooving film layer 31). Simultaneously, the laser beam emitted by the laser 40 exits via the laser transfer carrier 10. The laser transfer carrier 10 is moved relative to the cell precursor based on the laser transmittance of the area above the grooving region aligned with the laser 40 and / or the laser reflectivity between the laser transfer carrier and the laser, until the centerline of the guide plate portion 11 is aligned with the centerline of the grooving region. A laser beam collector can be provided in the laser 50 emission region to receive the reflected laser beam, and the laser reflectivity between the laser transfer carrier and the laser 50 emitted by the laser 40 is calculated based on the received reflected laser beam and the laser 50 emitted by the laser 40.

[0074] In these embodiments, the setting of the limiting groove 61 helps to improve the alignment of the position and width between the laser 50 and the guide plate 11 in the S40 laser grooving step, improve the accuracy of laser grooving, ensure the quality of solar cell grid line 21 fabrication and the quality of the final solar cell, and also avoid the laser 50 from acting on the non-grooving area of ​​the film layer 31 to be grouted, thereby reducing surface damage to the battery and reducing recombination.

[0075] like Figure 10 As shown, in some embodiments of this application, the positioning part 60 is a filling groove 12 filled with paste 20, and the second transfer area B also includes a guide plate part 11. Multiple guide plate parts 11 and filling grooves 12 filled with paste 20 are alternately arranged in the second transfer area B, where D = (2n+1)×d, and n is a positive integer greater than 1.

[0076] In these embodiments, the filling groove 12 of the second transfer area B filled with slurry 20 can act as a positioning part 60 when the battery grid lines 21 of the first battery cell precursor are prepared using the first transfer area A. Multiple guide plate parts 11 and filling grooves 12 filled with slurry 20 are alternately arranged in the second transfer area B, and D = (2n+1)×d, where n is a positive integer greater than 1. After the battery grid lines 21 of the first battery cell precursor are prepared (i.e., the slurry 20 in the filling groove 12 of the first transfer area A of the laser transfer substrate 10 is completely transferred to the first battery cell precursor), the filling groove 12 in the second transfer area B of the same laser transfer substrate 10 can be used to prepare the grid lines 21 of a new second battery cell precursor to be printed in the same laser device using the method for preparing solar cell grid lines 21 provided in the embodiments of this application. In these embodiments, the utilization rate of the laser transfer substrate 10 is improved, the number of times the laser transfer substrate 10 needs to be replaced is reduced, the preparation time for the fabrication of the gate line 21 is shortened, the efficiency of the fabrication of the gate line 21 is greatly improved, and the cost of fabricating the gate line 21 is reduced.

[0077] The following combination Figures 11 to 16 The process of preparing solar cell grid lines 21 using the laser transfer substrate 10 in the above embodiments is described in detail.

[0078] like Figure 11 and Figure 12 As shown, another embodiment of this application provides a method for fabricating a solar cell grid line 21, comprising:

[0079] S10': Provide a first cell precursor with a grooving film layer 31, the grooving film layer 31 including a grooving area for forming grid lines 21, and a plurality of grooving areas are arranged at intervals of D with their respective centerline spacing.

[0080] S20': Provides a laser transfer substrate 10, which includes a plurality of first transfer areas A arranged at intervals of k, where k equals Dd and k>0. Each first transfer area A has a guide plate portion 11 and a filling groove 12 connected to each other and with a width of d. The filling groove 12 is filled with paste 20 and is raised relative to the plane of the guide plate portion 11. The laser transfer substrate 10 also includes a second transfer area B, which is located between two adjacent first transfer areas A and is connected to the first transfer areas A. The second transfer area B has a positioning portion 60, which is arranged opposite to the filling groove 12 on both sides of the guide plate portion 11 and is connected to the guide plate portion 11. The positioning portion 60 is the filling groove 12 filled with paste 20. The second transfer area B also includes a guide plate portion 11. A plurality of guide plate portions 11 and filling grooves 12 filled with paste 20 are alternately arranged in the second transfer area B, where D=(2n+1)×d, and n is a positive integer greater than 1.

[0081] S30': Align the center line of a guide plate portion 11 with the center line of a grooving area;

[0082] S40': Laser grooving, the laser 50 emitted by the laser 40 grooves the area to be grooved through the guide plate 11 to form a groove 311 with a width of d in the film layer 31 to be grooved. In the laser emission direction Z, the front body of the battery cell and the laser transfer carrier plate 10 are arranged parallel to each other at intervals.

[0083] S50': Transfer of grid line 21, move the laser transfer plate 10 horizontally along the first direction X by a distance d, so that the filling groove 12 corresponds to the groove opening 311, use laser 50 to transfer the paste 20 in the filling groove 12 to the groove opening 311, and complete the transfer of one grid line 21. Move the laser 40 horizontally along the second direction Y by a distance D.

[0084] Repeat the steps of laser grooving and grid line 21 transfer until all grid lines 21 corresponding to the grooving areas in the grooving film layer 31 of the first battery cell precursor are fabricated. The second direction Y is opposite to the first direction X and is perpendicular to the laser emission direction Z.

[0085] S60': Provide a second cell precursor with a grooving film layer 31 (a new cell precursor compared to the first cell precursor), the grooving film layer 31 includes a grooving area for forming grid lines 21, and a plurality of grooving areas are arranged at intervals of D with their respective centerline spacing.

[0086] S70': Provides a laser transfer substrate 10 that has been used to fabricate the first solar cell front grid lines and is in a usable state;

[0087] S80': Align the center line of a guide plate portion 11 in the second transfer area B of the laser transfer substrate 10, which is in a usable state, with the center line of a slotted area in the second cell precursor (new cell precursor).

[0088] Repeat the steps S40' laser grooving and S50' grid line 21 transfer until all grid lines 21 corresponding to the grooving areas in the grooving film layer 31 of the second battery cell precursor are fabricated. The second direction Y is opposite to the first direction X and is perpendicular to the laser emission direction Z.

[0089] In some optional embodiments of this application, the preparation method further includes, after step S80', the following step: S90': determining whether there is a filling groove 12 filled with paste in each of the second transfer areas B of the laser transfer substrate 10. If yes, the laser transfer substrate 10 remains usable and continues to be used for fabricating new battery cell front grid lines. If no, the laser transfer substrate 10 is replaced. Specifically, the presence of a filling groove 12 filled with paste in the second transfer area B can be determined by the reflectivity or transmittance of the laser. In some examples, when the filling groove 12 is filled with paste, the transmittance of the laser in the filling groove 12 decreases; when the filling groove 12 is filled with paste, the laser incident on the filling groove 12 is reflected by the paste, resulting in high reflectivity. Alternatively, an image can be captured by an imaging device to determine whether there is a filling groove 12 filled with paste in the second transfer area B.

[0090] In these embodiments, a single laser transfer substrate 10 can be used to fabricate grid lines 21 for multiple solar cell precursors, avoiding the problems of high cost and low fabrication efficiency caused by frequent replacement of the laser transfer substrate 10.

[0091] In some optional embodiments of this application, the opening size of the filling groove is greater than or equal to the size of other positions of the filling groove in the direction of the filling groove protrusion. In these embodiments, the opening size of the filling groove is greater than or equal to the size of other positions of the filling groove, which ensures that the grid lines formed by the paste are adapted to the groove width of the film layer 31 to be grooved, while saving paste for making the grid lines 21 and reducing the manufacturing cost of solar cell grid lines.

[0092] In some optional embodiments of this application, in the step of providing the laser transfer substrate 10, the cross-sectional shape of the filling groove 12 is selected from any one of trapezoidal, rectangular and triangular shapes.

[0093] In some optional embodiments of this application, the step of providing the laser transfer substrate 10 is as follows: Figure 13 As shown, the filling groove 12 is continuously filled with slurry 20. In the laser grooving step, the groove opening 311 is a continuous groove opening 31. For example... Figure 15 As shown, continuous grooves 311 are formed on the film layer 30 to be grooved, and the grooves are transferred by laser transfer. Figure 13 The slurry 20 continuously filled in the filling groove 12 is transferred onto the front of the solar cell, forming... Figure 15 The grid lines 21 are continuous and uninterrupted.

[0094] In some alternative embodiments of this application, the step of providing the laser transfer substrate 10 is as follows: Figure 14 As shown, the filling groove 12 is intermittently filled with slurry 20. In the laser grooving step, the groove opening 311 is an intermittent groove opening 311. For example... Figure 16Intermittent grooves 311 are formed on the film layer 30 to be grooved, and the grooves are transferred by laser transfer. Figure 14 The slurry 20, which is intermittently filled in the filling groove 12 shown, is transferred onto the front of the solar cell, forming intermittent grid lines 21. In some optional embodiments of this application, the value of d ranges from 5μm to 80μm, for example, it can be 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, or 80μm, etc.

[0095] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for fabricating solar cell grid lines, characterized in that, include: A cell precursor with a grooving film layer is provided, the grooving film layer including a grooving region for forming grid lines, and a plurality of the grooving regions are arranged at intervals of D with their respective centerline spacing. A laser transfer substrate is provided, the laser transfer substrate comprising a plurality of first transfer zones arranged at intervals of k, where k equals k > 0, each of the first transfer areas has a guide plate portion and a filling groove that are connected and have a width of d. The filling groove is filled with paste and is provided to protrude relative to the plane where the guide plate portion is located. Align the center line of one of the guide plates with the center line of the area to be slotted. Laser grooving: The first laser beam emitted by the laser emits a groove in the area to be grooved through the guide plate to form a groove with a width of d in the film layer to be grooved. In the laser emission direction, the front body of the battery cell and the laser transfer carrier are arranged parallel to each other at intervals. For grid line transfer, the laser transfer plate is moved horizontally a distance d along the first direction so that the filling groove corresponds to the groove opening. The paste in the filling groove is transferred to the groove opening by laser to complete one grid line transfer. The laser is then moved horizontally a distance D along the second direction. Repeat the laser grooving and grid line transfer steps until all grid lines corresponding to the grooving areas in the grooving film layer of the battery cell precursor are fabricated, wherein the second direction is opposite to the first direction and both are perpendicular to the laser emission direction.

2. The preparation method according to claim 1, characterized in that, In the step of providing the laser transfer substrate, the laser transfer substrate further includes: The second transfer area is located between two adjacent first transfer areas and is connected to the first transfer area. The second transfer area has a positioning part, which is disposed opposite to the filling groove on both sides of the guide plate and is connected to the guide plate. The positioning part is used to assist laser alignment and prevent the laser from acting on the non-grooving area of ​​the film layer to be grooved.

3. The preparation method according to claim 2, characterized in that, The step of aligning the center line of one of the guide plate portions with the center line of one of the areas to be slotted includes: Reference marks are set on both sides of the area to be slotted, and the position information of the area to be slotted is obtained according to the reference marks. The laser is controlled to move relative to the cell front body according to the position information of the area to be slotted, until the second laser beam emitted by the laser covers one of the areas to be slotted, thus completing the alignment of the laser with one of the areas to be slotted in the cell front body. The beam width of the first laser beam and the second laser beam is equal to the width of the area to be slotted, the power of the first laser beam is greater than the power of the second laser beam, and the second laser beam does not act on the film layer to be slotted. The guide plate portion of the laser transfer carrier is positioned between the laser and the front body of the battery cell. Simultaneously, the second laser beam emitted by the laser is emitted through the laser transfer carrier. Based on the laser transmittance of the area above the area to be slotted, which is aligned with the laser, and / or the laser reflectivity between the laser transfer carrier and the laser, the laser transfer carrier is controlled to move relative to the front body of the battery cell until the center line of the guide plate portion is aligned with the center line of the area to be slotted.

4. The preparation method according to claim 2, characterized in that, The second transfer area also includes a connecting plate portion, which connects the positioning portion to the filling groove in the adjacent first transfer area.

5. The preparation method according to any one of claims 2 to 4, characterized in that, The positioning part includes laser protection material. Alternatively, the positioning portion may include a laser protective layer covering the substrate of the laser transfer carrier.

6. The preparation method according to any one of claims 2 to 4, characterized in that, The positioning part includes a limiting groove, which is protruding relative to the guide plate part, and the surface of the protruding limiting groove is covered with a laser reflective layer.

7. The preparation method according to claim 2, characterized in that, The positioning part is the filling groove filled with paste, and the second transfer area also includes the guide plate part. Multiple guide plates and filling grooves filled with paste are alternately arranged in the second transfer area, where D=(2n+1)×d, and n is a positive integer greater than 1.

8. The preparation method according to claim 7, characterized in that, The value of d ranges from 5μm to 80μm.

9. The preparation method according to claim 7, characterized in that, After completing the fabrication of the grid lines corresponding to all the areas to be slotted in the grooving film layer of the battery cell precursor, the preparation method further includes: Provide a new cell precursor having the aforementioned grooved film layer; Provides a laser transfer substrate that has been used to fabricate a front grid line of a battery cell using the paste in the first transfer area and is in a usable state; Align the center line of a guide plate portion in the second transfer area of ​​the laser transfer substrate that is in a usable state with the center line of a slotted area in the new cell precursor. Repeat the laser grooving and grid line transfer steps until all grid lines corresponding to the grooving areas in the grooving film layer of the new solar cell precursor are fabricated.

10. The preparation method according to claim 9, characterized in that, If it is determined whether there is a filling groove filled with paste in each of the second transfer areas of the laser transfer substrate, and if so, the laser transfer substrate is still usable and can continue to be used to fabricate new battery cell front grid lines. If not, the laser transfer substrate is replaced.

11. The preparation method according to claim 1, characterized in that, In the step of providing the laser transfer substrate, in the direction of the protrusion of the filling groove, the size of the groove opening is greater than or equal to the size of other positions of the filling groove.

12. The preparation method according to claim 11, characterized in that, The cross-sectional shape of the filling groove is selected from any one of trapezoidal, rectangular and triangular shapes.

13. The preparation method according to claim 1, characterized in that, In the step of providing the laser transfer substrate, the filling groove is continuously filled with the paste, and in the step of laser grooving, the groove opening is a continuous groove opening; Alternatively, in the step of providing the laser transfer substrate, the filling groove is intermittently filled with the slurry, and in the step of laser grooving, the groove opening is an intermittent groove opening.

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