Non-contact metallization process

Abstract

The application discloses a non-contact metallization process applied to preparation of a photovoltaic cell, and comprises the following steps: providing a glass substrate, wherein the glass substrate has oppositely arranged front and back surfaces, the front surface of the glass substrate is provided with a groove, the width of the groove is not less than 3 um, and the depth of the groove is not less than 5 um; filling slurry in the groove of the glass substrate; providing an accepting substrate; keeping the front surface of the glass substrate and the accepting substrate in relative position with a certain interval; and emitting light towards the back surface of the glass substrate so as to transfer the slurry in the groove to the accepting substrate. The non-contact metallization process has the advantages of high precision and low cost.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell manufacturing technology, and in particular to a non-contact metallization process. Background Technology

[0002] The global energy transition is an inevitable trend, and the photovoltaic market will expand rapidly, with production capacity further increasing. Metallization is a necessary process step for crystalline silicon photovoltaic cells. The biggest technological change in the photovoltaic industry is the shift from P-type to N-type cells. Large-scale industrialization of N-type cells necessitates considering cost reduction through metallization. Silver paste accounts for the largest share of non-silicon costs, approximately 33%, and about 8% of the overall cell cost. Therefore, reducing silver paste consumption has become a pressing issue for the industry.

[0003] Metallization technology can be broadly categorized into contact and non-contact methods. Contact methods are primarily used in screen printing, while non-contact methods are mainly used in laser transfer technology. Traditional screen printing, limited by its paste, screen, and printing method, cannot meet the demands of photovoltaics for reduced silver paste consumption. Furthermore, traditional screen printing requires contact with the silicon wafer during printing; however, with the trend towards thinner wafers, this contact process easily leads to problems such as wafer breakage, scratches, contamination, and microcracks, thus affecting product yield.

[0004] Due to the various shortcomings of screen printing technology, laser transfer technology, with its advantages such as fine grid lines, excellent aspect ratio, low energy consumption, and non-contact operation, has become the main technical means to replace traditional screen printing.

[0005] Current laser transfer technology involves creating grooves of the desired paste shape on a specific flexible film, filling the grooves with paste facing the solar cell, and then using a laser beam to scan the groove pattern from the opposite side, transferring the paste from the grooves to the cell surface to form grid lines. By setting the groove pattern and shape on the flexible film, laser transfer technology can overcome the linewidth limit of traditional screen printing, achieving linewidths below 25µm, thus achieving a better aspect ratio, improving cell conversion efficiency, and reducing paste consumption. Furthermore, the grid line consistency and uniformity of laser transfer are superior to traditional screen printing, and the non-contact printing method is more suitable for thin-film applications. Moreover, laser transfer technology has no limitations on cell structure and has broad application prospects in PERC, Topcon, HJT, and IBC cells.

[0006] In this laser transfer technology, flexible films are used as the substrate to carry the slurry. While the transfer of the slurry is possible, flexible films suffer from several drawbacks: high material costs, high usage costs (primarily due to the need to ensure consistent tension during the transfer process), and low reusability. These issues contribute to the high application cost of laser transfer solutions using flexible films. Furthermore, because flexible films are inherently flexible, it is difficult to guarantee consistent grid line widths during the transfer process. Additionally, long-term use can lead to material fatigue, resulting in reduced processing precision. Summary of the Invention

[0007] The main objective of this invention is to propose a non-contact metallization process, which aims to solve the technical problems of high application cost and reduced process accuracy caused by long-term repeated use of flexible films in laser transfer schemes.

[0008] To achieve the above objectives, the present invention proposes a non-contact metallization process, comprising:

[0009] A glass substrate is provided, the glass substrate having a front side and a back side disposed opposite to each other, the front side of the glass substrate having a groove, the width of the groove being not less than 3 μm and the depth of the groove being not less than 5 μm;

[0010] Fill the grooves in the glass substrate with paste;

[0011] Provide a substrate for acceptance;

[0012] The front side of the glass substrate and the receiving substrate are kept opposite each other at a certain interval;

[0013] Light is emitted toward the back of the glass substrate to transfer the paste in the trench to the receiving substrate.

[0014] In some embodiments, filling the trenches in the glass substrate with a paste includes:

[0015] The trench is filled with slurry;

[0016] The blade of the scraper is controlled to adhere to the front side of the glass substrate, and the scraper is controlled to move at least once on the front side of the glass substrate to scrape off the slurry layer on the surface of the glass substrate.

[0017] In some embodiments, the scraper is controlled to move in a direction parallel to or perpendicular to the groove.

[0018] In some embodiments, keeping the front side of the glass substrate opposite to the receiving substrate at a certain interval includes:

[0019] Flip at least one of the glass substrate and the receiving substrate so that the front side of the glass substrate faces the direction of the receiving substrate;

[0020] Move at least one of the glass substrate and the receiving substrate so that the glass substrate and the receiving substrate remain opposite each other at a certain interval in a set transfer station.

[0021] In some embodiments, the glass substrate and the receiving substrate are kept relative to each other at a certain interval in a set transfer station, and the positions of the glass substrate and the receiving substrate are corrected.

[0022] In some embodiments, positional correction of the glass substrate and the receiving substrate includes:

[0023] Before the glass substrate and the receiving substrate enter the transfer station, images are taken of the glass substrate and the receiving substrate;

[0024] The displacement compensation of the glass substrate and the receiving substrate is determined based on the image acquisition results;

[0025] The glass substrate and the receiving substrate are driven into the transfer station according to the displacement compensation.

[0026] In some embodiments, the gap between the glass substrate and the receiving substrate is not less than 30 μm and not more than 200 μm.

[0027] In some embodiments, emitting light toward the back side of the glass substrate includes:

[0028] A laser beam is emitted toward the back side of the glass substrate.

[0029] In some embodiments, the wavelength of the laser beam is 800 nm to 1080 nm.

[0030] In some embodiments, the wavelength of the laser beam is at least one of the following wavelengths:

[0031] 800nm, 910nm, 980nm, 1030nm~1080nm.

[0032] In some embodiments, the power of the laser beam is 10W to 2000W.

[0033] In some embodiments, the laser beam is controlled to scan the trenches line by line in a set order so that the paste in the trenches is transferred onto the receiving substrate.

[0034] In some embodiments, emitting light toward the back side of the glass substrate includes:

[0035] A non-laser beam is emitted toward the back of the glass substrate by at least one of the following: an ultraviolet lamp, a light-emitting diode, a broadband flash lamp, or an area array light source.

[0036] In some embodiments, the process further includes:

[0037] At least two glass substrates are provided, such that the at least two glass substrates alternately perform paste transfer of the receiving substrate.

[0038] In general, the present invention has the following advantages compared with the prior art:

[0039] (1) Non-contact: It can be applied to non-contact photovoltaic cell preparation equipment and processes, so that there is no need to contact the silicon wafer during the transfer process, thereby better protecting the product and reducing the probability of product breakage, scratches, contamination, microcracks, etc., which is conducive to the development of thinner silicon wafers.

[0040] (2) Higher precision: It can not only achieve grid lines with a minimum line width of 3um, but also ensure the flatness of the trench edges due to the rigid material of the glass substrate, so that the grid lines transferred are neat, which is conducive to achieving a better aspect ratio, improving battery conversion efficiency and reducing paste consumption.

[0041] (3) Good stability: The glass substrate has a high surface flatness, high light transmittance, strong durability, and high reusability.

[0042] (4) Low cost: After using glass substrate, there is no need for customized steel mesh template. Furthermore, glass substrate is easy to clean and has a high reusability, which can reduce consumables and lower costs. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0044] Figure 1 This is a process flow diagram of an embodiment of the non-contact metallization process of the present invention;

[0045] Figure 2 This is a schematic diagram of the structure of a glass substrate in one embodiment of the non-contact metallization process of the present invention;

[0046] Figure 3 This is a flowchart illustrating an embodiment of the non-contact metallization process of the present invention.

[0047] Figure 4This is a schematic diagram of the scraper's movement direction in one embodiment of the non-contact metallization process of the present invention;

[0048] Figure 5 This is a schematic diagram of the scraper's movement direction in another embodiment of the non-contact metallization process of the present invention;

[0049] Figure 6 This is a module flowchart of another embodiment of the non-contact metallization process of the present invention;

[0050] Figure 7 This is a schematic diagram of the structure of a glass substrate in another embodiment of the non-contact metallization process of the present invention.

[0051] Explanation of icon numbers:

[0052] 10. Glass substrate; 10a. Front side; 10b. Back side; 11. Groove; 12. Fine grid groove; 13. Coarse grid groove; 20. Receiving substrate; 30. Light source; 40. Slurry filling station; 41. Squeegee; 50. Flipping station; 60. Transfer station; 70. CCD image acquisition station; 71. CCD image sensor; 80. Finished product

[0053] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0055] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0056] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0057] This invention proposes a non-contact metallization process for the fabrication of photovoltaic cells, specifically for creating grid lines on silicon wafers. Alternatively, laser transfer metallization is a typical non-contact photovoltaic cell fabrication equipment and process. For ease of understanding, the following description uses laser transfer as an example of the applied non-contact metallization process.

[0058] In some embodiments, such as Figures 1 to 6 As shown, the non-contact metallization process of this application includes:

[0059] S10. A glass substrate 10 is provided. The glass substrate 10 has a front side 10a and a back side 10b disposed opposite to each other. The front side 10a of the glass substrate 10 is provided with a groove 11. The width of the groove 11 is not less than 3 μm and the depth of the groove 11 is not less than 5 μm.

[0060] Specifically, the glass substrate 10 is transparent, allowing light to travel from the front side 10a to the back side 10b of the glass substrate 10, and vice versa. The transparent glass substrate 10 allows laser light irradiated from the back side 10b of the glass substrate 10 to transfer energy to the slurry in the trench 11, thereby causing the slurry to detach from the trench 11.

[0061] In some embodiments, the light transmittance of the glass substrate 10 is not less than 80%. This configuration not only facilitates the alignment of the glass substrate 10 with the silicon wafer, but also reduces laser energy loss, thereby lowering the power consumption requirements for the laser.

[0062] For example, the light transmittance of the glass substrate 10 can be set to 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, etc.

[0063] In practical applications, trenches 11 are adaptively manufactured on the front side 10a of the glass substrate 10 according to the actual product requirements / design requirements of the solar cell (photovoltaic cell). These requirements for the trenches 11 include, but are not limited to, the specific dimensions of the trenches 11, the number of trenches 11, the shape of the trenches 11, and the pattern formed by the trenches 11. The pattern formed by the trenches 11 is determined based on the grid line pattern on the produced silicon wafer.

[0064] Due to unavoidable production errors in actual production, the width of the trench 11 on the glass substrate 10 is actually consistent with the expected width of the grid line on the photovoltaic cell, and the depth of the trench 11 is actually basically consistent with the expected height of the grid line on the photovoltaic cell.

[0065] For example, the width of the groove 11 can be set to 3um, 4um, 5um, 6um, 7um, 8um, 9um, 10um, 11um, 12um, 13mm, 14um, 15um, 16um, 17um, 18um, 19um, 20um, 21um, 22um, 23mm, 24um, 25um, 26um, 27um, 28um, 29um, 30um, 31um, 32um, 33mm, 34um, 35um, 36um, 37um, 38um, 39um, 40um, 41um, 42um, 43mm, 44um, 45um, 46um, 47um, 48um, 49um, 50um, 51um, 52um, 53mm, 54um, 55um, 56u m, 57um, 58um, 59um, 60um, 61um, 62um, 63mm, 64um, 65um, 66um, 67um, 68um, 69um, 70um, 71um, 72um, 73mm, 74um, 7 5um, 76um, 77um, 78um, 79um, 80um, 81um, 82um, 83mm, 84um, 85um, 86um, 87um, 88um, 89um, 90um, 91um, 92um, 93m m, 94um, 95um, 96um, 97um, 98um, 99um, 100um, 110um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um, 2 00um, 210um, 220um, 230um, 240um, 250um, 260um, 270um, 280um, 290um, 300um, 310um, 320um, 330um, 340um, 350u m, 360um, 370um, 380um, 390um, 400um, 410um, 420um, 430um, 440um, 450um, 460um, 470um, 480um, 490um, 500um, etc.

[0066] For example, the depth of trench 11 can be set to 5um, 6um, 7um, 8um, 9um, 10um, 11um, 12um, 13mm, 14um, 15um, 16um, 17um, 18um, 19um, 20um, 21um, 22um, 23mm, 24um, 25um, 26um, 27um, 28um, 29um, 30um, 31um, 32um, 33mm, 34um, 35um, 36um, 37um, 38um, 39um, 40um, 41um, 42um, 43mm, 44um, 45um, 46um, 47um, 48um, 49um, 50um, 51um, 52um, 53mm, 54um, 55um, 56um, 57um. 58um, 59um, 60um, 61um, 62um, 63mm, 64um, 65um, 66um, 67um, 68um, 69um, 70um, 71um, 72um, 73mm, 74um, 75um, 76um, 77um, 78um, 79um, 80um, 81um, 82um, 83mm, 84um, 85u m.

[0067] In some embodiments, the width-to-depth ratio of the trench 11 is between 1:1 and 20:1. For example, when the width of the trench 11 is between 5 μm and 100 μm, the depth of the trench 11 can be set between 5 μm and 100 μm. This setting balances the fabrication cost of the glass substrate 10 with the density of the trenches 11 on the glass substrate 10, thereby enabling the acquisition of photovoltaic cells with superior performance at a lower cost.

[0068] In some embodiments, an opening can be created on the front side 10a of the glass substrate 10 using a laser to obtain the desired trench 11. Specifically, the laser beam can be controlled to move along a path conforming to the desired trench 11 on the front side 10a of the glass substrate 10, thereby creating the desired trench 11 on the front side 10a of the glass substrate 10 using the energy of the laser.

[0069] In some embodiments, the desired trenches 11 can be etched on the front side 10a of the glass substrate 10 by etching. Specifically, according to the product requirements of the photovoltaic cell, a trench 11 pattern is first pre-formed on the front side 10a of the glass substrate 10, and then the front side 10a of the glass substrate 10 is etched by chemical etching or photolithography to obtain the desired trenches 11.

[0070] Understandably, due to the better rigidity of the glass substrate 10, it is more conducive to ensuring the accuracy of the trench 11 compared to the flexible film, and it is less prone to deformation, which is more conducive to ensuring the process accuracy under long-term use.

[0071] S20. Fill the groove 11 of the glass substrate 10 with paste.

[0072] In some embodiments, filling the grooves 11 of the glass substrate 10 with paste can be achieved by the following means:

[0073] The blade of the control scraper 41 is attached to the front surface 10a of the glass substrate 10, and the control scraper 41 is moved at least once on the front surface 10a of the glass substrate 10 to fill the groove 11 with slurry and scrape off the slurry on the surface of the glass substrate 10.

[0074] Specifically, the required slurry can be filled into the grooves 11 of the glass substrate 10 using a coating device at a designated slurry filling station 40. For example, this coating device can be a doctor blade 41. Specifically, when filling the grooves 11 of the glass substrate 10 with slurry, slurry can be added to the surface of the glass substrate 10 first, and then the doctor blade 41 is controlled to move along the front side 10a of the glass substrate 10 to push the slurry into the grooves 11. Simultaneously, as the doctor blade 41 moves, it can also scrape away excess slurry from the surface of the glass substrate 10, preventing slurry residue from remaining outside the grooves 11. Furthermore, based on the filling effect of the slurry in the grooves 11 (the amount of slurry filled) and the scraping effect on the grooves of the glass substrate 10 surface, the number of times the doctor blade 41 moves on the surface of the glass substrate 10 can be adaptively adjusted. For example, when the slurry filling effect in the trench 11 is good and the slurry on the surface of the glass substrate 11 is sufficiently scraped off, the scraper 41 can be controlled to move once on the surface of the glass substrate 10; when the slurry filling effect in the trench 11 is poor and the slurry on the surface of the glass substrate 11 is insufficient, the scraper 41 can be controlled to move twice or more on the surface of the glass substrate 10. It should be understood that when the scraper 41 moves twice or more, the scraper 41 can be controlled to move at least twice in the same direction, or the scraper 41 can be controlled to move back and forth on both sides of the glass substrate 10, or the scraper 41 can be controlled to move in a different direction each time.

[0075] It is worth noting that during the scraper 41 process, the slurry filling head and other mechanisms can be controlled to automatically replenish slurry on the front side 10a of the glass substrate 10 to ensure that enough slurry is filled into the trench 11.

[0076] It is also worth noting that when filling the slurry, the slurry can be filled into all the grooves 11 of the glass substrate 10 at one time, or only some of the grooves 11 can be filled with slurry. Depending on the number and position of the grooves 11 being filled, the size, number of moves and movement path of the scraper 41 can be adjusted accordingly.

[0077] In some embodiments, the grooves 11 are arranged at intervals along one edge of the front surface 10a of the glass substrate 10. Based on the arrangement of the grooves 11, when applying the slurry, the scraper 41 can be controlled to move in a direction parallel to the grooves 11. Alternatively, the scraper 41 can also be controlled to move in a direction perpendicular to the grooves 11. Both of these scraper 41 movement methods can more easily cover the entire front surface 10a of the glass substrate 10, thereby removing excess slurry more efficiently. It should be understood that when the scraper 41 needs to move at least twice along the surface of the glass substrate 10, the scraper 41 can be controlled to move in a direction parallel to the grooves 11 during the first movement, and to move in a direction perpendicular to the grooves 11 during the second movement. Of course, the reverse is also possible.

[0078] It is also worth noting that if the angle between the moving direction of the scraper 41 and the extending direction of the groove 11 is between 0° and 10°, the moving direction of the scraper 41 can be considered parallel to the groove 11. Correspondingly, if the angle between the moving direction of the scraper 41 and the extending direction of the groove 11 is between 80° and 90°, the moving direction of the scraper 41 can be considered perpendicular to the groove 11.

[0079] Of course, the design of this application is not limited to this. In other embodiments, the scraper 41 can also be controlled to move in other directions.

[0080] Understandably, using trench 11 for slurry filling is not only simple and convenient, but also more precise, which is conducive to obtaining higher precision grid lines. In addition, when filling slurry in trench 11, it is easier to obtain grid lines with a relatively smaller width and a relatively thicker thickness, thereby obtaining higher performance photovoltaic cells.

[0081] In some embodiments, the paste can be any conductive paste material known in the prior art. For example, silver-based pastes, such as low-temperature silver paste and high-temperature silver paste. The distinction between low-temperature and high-temperature silver paste varies depending on the actual production specifications. For instance, silver paste with a temperature below 200°C to 350°C can be defined as low-temperature silver paste, and silver paste with a temperature above 200°C to 350°C can be defined as high-temperature silver paste. Typically, pastes used in solar energy applications are compositions of four different materials: metal powder, glass powder and modifiers, volatile solvents, and non-volatile polymers or resins.

[0082] S30, Provide a receiving substrate 20.

[0083] In some embodiments, the receiving substrate 20 is a silicon wafer of a photovoltaic cell, which can be further processed to obtain a photovoltaic cell flat panel.

[0084] S40, keep the front side 10a of the glass substrate 10 and the receiving substrate 20 facing each other at a certain interval.

[0085] In some embodiments, the gap between the glass substrate 10 and the receiving substrate 20 is not less than 30 μm and not more than 200 μm. Specifically, maintaining a gap of not less than 30 μm between the glass substrate 10 and the silicon wafer ensures that the glass substrate 10 and the silicon wafer are in a non-contact state, thereby avoiding problems such as microcracks, fragmentation, contamination, and scratches that exist in extrusion printing, thus facilitating the thin-film design of the silicon wafer. Setting the gap between the glass substrate 10 and the silicon wafer to not more than 200 μm ensures the accuracy of laser transfer and achieves precise transfer of the paste.

[0086] For example, the interval can be set to 30um, 31um, 32um, 33mm, 34um, 35um, 36um, 37um, 38um, 39um, 40um, 41um, 42um, 43mm, 44um, 45um, 46um, 47um, 48um, 49um, 50um, 51um, 52um, 53mm, 54um, 55um, 56um, 57um, 58um, 59um, 60um, 61um, 62um, 63mm, 64um, 65um, 66um, 67um, 68um, 69um, 7 0um, 71um, 72um, 73mm, 74um, 75um, 76um, 77um, 78um, 79um, 80um, 81um, 82um, 83mm, 84um, 85um, 86um, 87um, 88um, 89um, 90um, 91u m, 92um, 93mm, 94um, 95um, 96um, 97um, 98um, 99um, 100um, 110um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um, 200um.

[0087] In some embodiments, maintaining the front surface 10a of the glass substrate 10 and the receiving substrate 20 at a certain interval includes:

[0088] S41. Flip at least one of the glass substrate 10 and the receiving substrate 20 so that the front side 10a of the glass substrate 10 faces the direction where the receiving substrate 20 is located.

[0089] For example, after the slurry filling is completed, the glass substrate 10 can be flipped at a designated flipping station 50 so that the front surface 10a of the glass substrate 10 faces the direction where the receiving substrate 20 is located. For instance, when the receiving substrate 20 is located below the glass substrate 10, and the front surface 10a of the glass substrate 10 faces upward when the slurry is filled, then after the slurry filling is completed, the glass substrate 10 can be flipped 180° clockwise or counterclockwise so that the front surface 10a of the glass substrate 10 faces downward (i.e., towards the side where the receiving substrate 20 is located). The advantage of this arrangement is that it facilitates the filling of slurry in the trench 11 and the transfer of slurry in the trench 11 to the receiving substrate 20. Alternatively, the receiving substrate 20 can also be located on the side or above the glass substrate 10, and the flipping angle and direction of the glass substrate 10 can be adaptively adjusted according to the different positions of the receiving substrate 20 relative to the glass substrate 10.

[0090] Alternatively, after the slurry filling is completed, the angle of the glass substrate 10 can be kept unchanged, and the receiving substrate 20 can be flipped so that the front surface 10a of the glass substrate 10 faces the receiving substrate 20. Or, the glass substrate 10 and the receiving substrate 20 can be flipped simultaneously so that the front surface 10a of the glass substrate 10 faces the receiving substrate 20.

[0091] S42. Move at least one of the glass substrate 10 and the receiving substrate 20 so that the glass substrate 10 and the receiving substrate 20 are kept relative to each other at a certain interval in the set transfer station 60.

[0092] Here, the designated transfer station 60 is used to define the positions of the glass substrate 10 and the receiving substrate 20 to ensure that the transfer process is not disturbed. For example, a specific position can be designated as the transfer station 60 on a linear production line or a rotary production line.

[0093] In some embodiments, when the glass substrate 10 and the receiving substrate 20 are kept relative to each other at a certain interval in a set transfer station 60, the position of the glass substrate 10 and the receiving substrate 20 is corrected.

[0094] Specifically, by calibrating the positions of the glass substrate 10 and the receiving substrate 20, the position of the groove 11 on the glass substrate 10 can be matched with the position of the desired grid line on the receiving substrate 20, thereby ensuring the transfer accuracy.

[0095] In some embodiments, positional correction of the glass substrate 10 and the receiving substrate 20 includes:

[0096] S421. Before the glass substrate 10 and the receiving substrate 20 enter the transfer station 60, images are taken of the glass substrate 10 and the receiving substrate 20.

[0097] S422. Determine the displacement compensation of the glass substrate 10 and the receiving substrate 20 based on the image acquisition results.

[0098] S423. Drive the glass substrate 10 and the receiving substrate 20 into the transfer station 60 according to the displacement compensation.

[0099] Specifically, a CCD imaging station 70 can be designated between the flipping station 50 and the transfer station 60. Then, the CCD (charge-coupled device) imaging device 71 captures images of the glass substrate 10 and the receiving substrate 20. Based on the imaging results, the displacement compensation of the glass substrate 10 and the receiving substrate 20 relative to their expected positions is determined. This displacement compensation includes displacement compensation in the X, Y, and Z directions, and is not limited to positive compensation but also includes negative compensation. After obtaining the displacement compensation for each of the glass substrate 10 and the receiving substrate 20, the moving mechanism can control the movement of the glass substrate 10 and the receiving substrate 20 according to their respective displacement compensations, so that when the glass substrate 10 and the receiving substrate 20 arrive at the transfer station 60, they are exactly in their expected positions. This ensures the position and accuracy of the paste transfer.

[0100] It is worth noting that the design of this application is not limited to this. In other embodiments, when correcting the position of the glass substrate 10 and the receiving substrate 20, the position of either the glass substrate 10 or the receiving substrate 20 may be corrected so that one of them matches the position of the other.

[0101] Furthermore, since the glass substrate 10 and / or the receiving substrate 20 are flipped before entering the transfer station 60, in order to ensure the alignment accuracy of the glass substrate 10 and the receiving substrate 20, images of the glass substrate 10 and / or the receiving substrate 20 are captured after the flipping is completed. Alternatively, images can be captured before the flipping of the glass substrate 10 and / or the receiving substrate 20 is completed.

[0102] S50, light is emitted toward the back surface 10b of the glass substrate 10 so that the paste in the trench 11 is transferred onto the receiving substrate 20.

[0103] Specifically, a light source 30 can be provided on the back side 10b of the glass substrate 10. This light source 30 emits light towards the back side 10b of the glass substrate 10, transferring energy to the paste in the trench 11. This causes the paste to detach from the trench 11 and transfer to the receiving substrate 20. After the transfer is complete, the desired finished product 80 is obtained. To facilitate paste transfer, in step S40, the receiving substrate 20 is typically positioned below the glass substrate 10, with the front side 10a of the glass substrate 10 facing downwards and towards the receiving substrate 20.

[0104] In some embodiments, emitting light toward the back surface 10b of the glass substrate 10 includes emitting a laser beam toward the back surface 10b of the glass substrate 10.

[0105] Alternatively, a high-repetition-rate laser can be used to emit a continuous laser beam toward the back surface 10b of the glass substrate 10, and then the laser beam can be controlled to scan the grooves 11 on the glass substrate 10 line by line in a set sequence, so that the paste in the grooves 11 is transferred onto the receiving substrate 20. Alternatively, the laser beam can also scan the grooves 11 on the glass substrate 10 randomly, without having to follow a specific scanning sequence.

[0106] In some embodiments, the wavelength of the laser beam can be set to 800nm ​​to 1080nm. Optionally, the wavelength of the laser beam can be set to 800nm, 910nm, 980nm, 1030nm to 1080nm, etc. Specifically, within the 1030nm to 1080nm wavelength range, the laser wavelength can be set to 1030nm, 1031nm, 1032nm, 1033nm, 1034nm, 1035nm, 1036nm, 1037nm, 1038nm, 1039nm, 1040nm, 1041nm, 1042nm, 1043nm, 1044nm, 1045nm, 1046nm, 1047nm, 1048nm, 1049nm, 1050nm, 1051nm, 1052nm, etc. The wavelengths of the laser beam can be 0.53nm, 1054nm, 1055nm, 1056nm, 1057nm, 1058nm, 1059nm, 1060nm, 1061nm, 1062nm, 1063nm, 1064nm, 1065nm, 1066nm, 1067nm, 1068nm, 1069nm, 1070nm, 1071nm, 1072nm, 1073nm, 1074nm, 1075nm, 1076nm, 1077nm, 1078nm, 1079nm, 1080nm, etc. Of course, the design of this application is not limited to these; the wavelength of the laser beam can also be set to other values ​​not specifically exemplified within the range of 800nm ​​to 1080nm, such as 900nm, 950nm, 1000nm, etc.

[0107] It is worth noting that in the same transfer process, only one wavelength of laser beam can be used, or different wavelengths of laser beam can be used in different stages.

[0108] In some embodiments, the power of the laser beam is set to 10W to 2000W. For example, the power of the laser beam can be set to 10W, 15W, 20W, 25W, 30W, 35W, 40W, 45W, 50W, 55W, 60W, 65W, 70W, 75W, 80W, 85W, 90W, 100W, 110W, 120W, 130W, 140W, 150W, 160W, 170W, 180W, 190W, 2... 00W, 210W, 220W, 230W, 240W, 250W, 260W, 270W, 280W, 290W, 300W, 310W, 320W, 330 W, 340W, 350W, 360W, 370W, 380W, 390W, 400W, 410W, 420W, 430W, 440W, 450W, 460W, 4 70W, 480W, 490W, 500W, 510W, 520W, 530W, 540W, 550W, 560W, 570W, 580W, 590W, 600 W, 610W, 620W, 630W, 640W, 650W, 660W, 670W, 680W, 690W, 700W, 710W, 720W, 730W, 7 40W, 750W, 760W, 770W, 780W, 790W, 800W, 810W, 820W, 830W, 840W, 850W, 860W, 870W, 880W, 890W, 900W, 910W, 990W, 930W, 940W, 950W, 960W, 970W, 980W, 990W, 1000W, etc.

[0109] It is worth noting that in the same transfer process, only one power laser beam can be used, or different power laser beams can be used in different stages.

[0110] In some embodiments, emitting light toward the back surface 10b of the glass substrate 10 includes emitting a non-laser beam toward the back surface 10b of the glass substrate 10. Specifically, the non-laser beam can be emitted toward the back surface of the glass substrate by at least one of an ultraviolet (UV) lamp, a light-emitting diode (LED), a broadband flash lamp, or an area array light source. The light-emitting substrate of the area array light source can be an LED, UV, OLED, miniLED, microLED, etc. The non-laser beam emitted by the aforementioned light source can then transfer the paste in the trench 11 onto the glass substrate 10.

[0111] It is understood that the non-contact metallization process of this application, by replacing the flexible film with a glass substrate 10, carries and transfers the paste during the metallization process. This not only achieves higher precision and finer, thicker paste patterns (corresponding to the fabrication of higher precision and finer, thicker grid lines on photovoltaic cells) for higher-performance photovoltaic cells, but also utilizes the rigidity of the glass substrate 10 to save the cost required for tensioning the flexible film. Furthermore, compared to flexible films, the glass substrate 10 experiences slower wear and is easier to clean, resulting in a higher reusability rate and significantly reducing the cost of laser transfer. Therefore, the glass substrate 10 of this application not only improves the performance of photovoltaic cells but also reduces the cost of laser transfer.

[0112] In general, the present invention has the following advantages compared with the prior art:

[0113] (1) Non-contact: It can be applied to non-contact photovoltaic cell preparation equipment and processes, so that there is no need to contact the silicon wafer during the transfer process, thereby better protecting the product and reducing the probability of product breakage, scratches, contamination, microcracks, etc., which is conducive to the development of thinner silicon wafers.

[0114] (2) Higher precision: Not only can it achieve grid lines with a minimum line width of 3um, but also, since the glass substrate 10 is made of rigid material, it can ensure the flatness of the edge of the trench 11, so that the grid lines transferred are neat, which is conducive to achieving a better aspect ratio, improving battery conversion efficiency and reducing paste consumption.

[0115] (3) Good stability: The glass substrate has a high surface flatness, high light transmittance, strong durability, and high reusability.

[0116] (4) Low cost: After using glass substrate 10, there is no need for customized steel mesh template, and glass substrate 10 is easy to clean and has a high reusability, thereby reducing consumables and lowering costs.

[0117] In some embodiments, the non-contact metallization process of this application further includes: providing at least two glass substrates 10, such that the at least two glass substrates 10 alternately complete the paste transfer of the receiving substrate 20.

[0118] For example, such as Figure 3As shown, when four glass substrates 10 are provided, the non-contact metallization process of this application is as follows: When one glass substrate 10 is at the transfer station 60, the other three glass substrates 10 are respectively at the paste filling station 40, the flipping station 50, and the CCD imaging station 70. After the glass substrate 10 at the transfer station 60 has completed the transfer, the transferred glass substrate 60 can be transferred to the paste filling station 40 for paste filling. At the same time, the glass substrate 10 at the CCD imaging station 70 is moved to the transfer station 60 for transfer operation, the glass substrate 10 at the flipping station 50 is moved to the CCD imaging station 70 for image acquisition, and the glass substrate 10 at the paste filling station 40 is moved to the flipping station 50 for flipping. This cycle is repeated to complete the continuous transfer operation and achieve a high reusability rate of the glass substrates 10.

[0119] For example, such as Figure 6 As shown, when three glass substrates 10 are used, the non-contact metallization process of this application is as follows:

[0120] When one glass substrate 10 is at the transfer station 60, the other two glass substrates 10 are at the paste filling station 40 and the CCD imaging station 70, respectively. After the glass substrate 10 at the transfer station 60 has completed the transfer, it can be transferred to the paste filling station 40 for paste filling. Simultaneously, the glass substrate 10 at the CCD imaging station 70 is moved to the transfer station 60 for transfer, and the glass substrate 10 at the paste filling station 40 is moved to the CCD imaging station 70 for image acquisition. During this process, the glass substrate 10 is flipped while being moved from the paste filling station 40 to the CCD imaging station 70. This cycle is repeated to complete continuous transfer work and achieve a high reusability rate of the glass substrates 10.

[0121] For example, when two glass substrates 10 are used, the non-contact metallization process of this application is as follows:

[0122] While one glass substrate 10 is undergoing professional processing at the transfer station 60, the other glass substrate 10 sequentially completes slurry filling at the paste filling station 40 and CCD imaging at the CCD imaging station 70. When the glass substrate 10 at the transfer station 60 has completed the transfer, the other glass substrate 10 has just completed the CCD imaging operation or has completed the CCD imaging operation ahead of schedule. At this time, the glass substrate 60 that has completed the transfer can be transferred to the paste filling station 40 for paste filling, and the glass substrate 10 at the CCD imaging station 70 can be moved to the transfer station 60 for transfer. By repeating this cycle, continuous transfer work can be completed, and a high reusability rate of the glass substrate 10 can be achieved.

[0123] It should be understood that, in order to achieve continuous transfer, an additional moving mechanism can be provided to continuously move the untransferable receiving substrate 20 to the transfer station 60 and remove the transferred receiving substrate 20 from the transfer station 60.

[0124] It is understandable that the above process can significantly improve the transfer efficiency and increase the reusability of the glass substrate 10, thereby reducing the cost of the metallization process.

[0125] It is understood that the design of this application is not limited to providing two, three, or four glass substrates, but rather adapts to different production line scales by providing a corresponding number of glass substrates 10.

[0126] It is also worth noting that the non-contact metallization process provided in this application can use only one glass substrate 10 each time.

[0127] like Figure 7 As shown, in some embodiments, when trenches 11 of different widths can be simultaneously formed on the same glass substrate 10, for example, a silicon wafer (i.e., the receiving substrate 20) typically has both coarse gates (also called main gates) and fine gates, wherein the width of the coarse gates is greater than that of the fine gates. For silicon wafer paste transfer with both coarse and fine gates, the glass substrate 10 is provided with coarse gate trenches 13 and fine gate trenches 12 corresponding to the coarse and fine gates.

[0128] Furthermore, since the costs of fine-grid silver paste and coarse-grid silver paste differ (usually fine-grid silver paste is more expensive than coarse-grid silver paste), for cost considerations, the transfer is performed in two stages: first, the fine-grid is transferred, then the coarse-grid is transferred (or vice versa). When transferring the coarse-grid, all coarse-grid trenches 13 on the glass substrate 10 can be filled with coarse-grid silver paste simultaneously to complete the transfer in one go; alternatively, only a portion of the coarse-grid trenches 13 can be filled with coarse-grid silver paste each time, and this process is repeated until all coarse-grid silver paste on the glass substrate 10 is transferred. Similarly, when transferring the fine-grid, all fine-grid trenches 12 on the glass substrate 10 can be filled with fine-grid silver paste simultaneously to complete the transfer in one go; alternatively, only a portion of the fine-grid trenches 12 can be filled with fine-grid silver paste each time, and this process is repeated until all fine-grid silver paste on the glass substrate 10 is transferred. Similarly, when transferring the fine-grid,

[0129] Of course, the design of this application is not limited to this. In some embodiments, the transfer of coarse grid silver paste and fine grid silver paste can also be carried out in the same transfer process in one transfer operation, that is, the transfer of coarse grid silver paste and fine grid silver paste can be carried out simultaneously in one transfer process.

[0130] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A non-contact metallization process applied to the fabrication of photovoltaic cells, characterized in that, The metallization process includes: A glass substrate is provided, the glass substrate having a front side and a back side disposed opposite to each other, the front side of the glass substrate having a groove, the width of the groove being not less than 3 μm and the depth of the groove being not less than 5 μm; Fill the grooves in the glass substrate with paste; Provide a substrate for acceptance; Flip at least one of the glass substrate and the receiving substrate so that the front side of the glass substrate faces the direction of the receiving substrate; At least one of the glass substrate and the receiving substrate is moved such that the glass substrate and the receiving substrate remain opposite each other at a certain interval in a set transfer station, wherein... When the glass substrate and the receiving substrate are kept relative to each other at a certain interval in a set transfer station, before the glass substrate and the receiving substrate enter the transfer station, the glass substrate and the receiving substrate are imaged, the displacement compensation of the glass substrate and the receiving substrate is determined according to the image acquisition result, and the glass substrate and the receiving substrate are driven to enter the transfer station according to the displacement compensation. Light is emitted toward the back of the glass substrate to transfer the paste in the trench to the receiving substrate.

2. The non-contact metallization process as described in claim 1, characterized in that, Filling the trenches in the glass substrate with a paste, including: The blade of the scraper is controlled to adhere to the front side of the glass substrate, and the scraper is controlled to move at least once on the front side of the glass substrate to fill the groove with slurry and scrape off the slurry on the surface of the glass substrate.

3. The non-contact metallization process as described in claim 2, characterized in that, Control the scraper to move in a direction parallel or perpendicular to the groove.

4. The non-contact metallization process as described in claim 1, characterized in that, The displacement compensation includes displacement compensation in the X, Y, and Z directions.

5. The non-contact metallization process as described in claim 1, characterized in that, The gap between the glass substrate and the receiving substrate is not less than 30 μm and not more than 200 μm.

6. The non-contact metallization process as described in claim 1, characterized in that, Emitting light toward the back side of the glass substrate includes: A laser beam is emitted toward the back side of the glass substrate.

7. The non-contact metallization process as described in claim 6, characterized in that, The wavelength of the laser beam is 800nm ​​to 1080nm.

8. The non-contact metallization process as described in claim 7, characterized in that, The wavelength of the laser beam is at least one of the following wavelengths: 800nm, 910nm, 980nm, 1030nm~1080nm.

9. The non-contact metallization process as described in claim 6, characterized in that, The power of the laser beam is 10W to 2000W.

10. The non-contact metallization process as described in claim 6, characterized in that, The laser beam is controlled to scan the grooves line by line in a set order so that the paste in the grooves is transferred to the receiving substrate.

11. The non-contact metallization process as described in claim 1, characterized in that, Emitting light toward the back side of the glass substrate includes: A non-laser beam is emitted toward the back of the glass substrate.

12. The non-contact metallization process as described in claim 11, characterized in that, A non-laser beam is emitted toward the back of the glass substrate by at least one of the following: an ultraviolet lamp, a light-emitting diode, a broadband flash lamp, or an area array light source.

13. The non-contact metallization process as described in claim 1, characterized in that, The process also includes: At least two glass substrates are provided, such that the at least two glass substrates alternately perform paste transfer of the receiving substrate.

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