Carrier plate, laser printing device and laser printing method

Abstract

The invention discloses a carrier plate, a laser printing device and a laser printing method, and relates to the technical field of laser printing. The carrier plate comprises at least one groove, the grooves are formed in the surface of the same side of the carrier plate in a specified pattern and contain printing paste, and the printing paste can be released to the surface of the solar cell piece under laser irradiation. The cross section of the groove of the support plate is of a specially-designed arch structure, comprises the arch part and the side wall part, has the size in a specific range, and is combined with the shaped light spot and the laser with the special wavelength, so that the printing paste in the groove of the rigid support plate is easier to desorb; therefore, desorption of the printing paste can be promoted without adding a release layer in the carrier plate groove or increasing the content of organic release components in the printing paste. In combination with the laser printing method, the printed grid line is lower in line width, the height-width ratio of the grid line is larger, the quality of the grid line is high, the production efficiency is better improved, and the production cost is better reduced.

Description

Technical Field

[0001] The invention relates to the technical field of laser printing, and in particular to a carrier plate, a laser printing device and a laser printing method. Background Art

[0002] In the solar cell manufacturing process, traditional screen printing requires the design of a narrower opening screen and an ultra-fine grid printing pattern. As the opening continues to narrow, higher requirements are placed on the screen's opening rate and precision control. Currently, the narrowest grid line width using this technology can only be around 15μm, which is close to the technical limit.

[0003] Laser printing is a technology that uses laser to irradiate the metal slurry carried by a transparent carrier, causing the metal slurry to fall off from the grooves of the carrier and then transfer to the solar cell to form the grid electrode. However, in the prior art, in order to make the slurry fall off smoothly and take into account the needs of energy saving, the carriers used are mostly flexible materials or rigid and flexible combined materials, which can be reused a few times, have a short lifespan, and need to be replaced frequently, which not only has a high production cost but also affects production efficiency. Summary of the invention

[0004] The main purpose of the present invention is to develop a laser printing technology that can improve the aspect ratio of printed grid lines, reduce the line resistance of the grid lines, and reduce production costs and improve production efficiency.

[0005] To achieve the above objectives, the present invention proposes a carrier, which includes: at least one groove, which is arranged on the surface of the same side of the carrier in a specified pattern and contains printing paste, and the printing paste can be released to the surface of the solar cell under laser irradiation.

[0006] In one embodiment, the groove includes at least one of an arched groove, a square groove, a rectangular groove, a semicircular groove, a fan-shaped groove and a triangular groove.

[0007] In one embodiment, the groove is an arched groove, which includes an arched portion and a sidewall portion, wherein the angle of the arc of the arched portion is 15 degrees to 180 degrees, and the span of the arched portion is 5μm to 70μm; the groove width of the sidewall portion is 5μm to 80μm, and the depth of the sidewall portion is 5μm to 25μm.

[0008] In one embodiment, the carrier is used to print the main grid, and the arched groove includes an arched portion and a sidewall portion, wherein the angle of the arc of the arched portion is 15 degrees to 180 degrees, and the span of the arched portion is 15μm to 70μm; the groove width of the sidewall portion is 15μm to 80μm, and the depth of the sidewall portion is 5μm to 25μm.

[0009] In one embodiment, the carrier is used to print fine grids, and the arched groove includes an arched portion and a sidewall portion, wherein the angle of the arc of the arched portion is 15 degrees to 180 degrees, and the span of the arched portion is 5μm to 20μm; the groove width of the sidewall portion is 5μm to 25μm, and the depth of the sidewall portion is 8μm to 20μm.

[0010] In one embodiment, the carrier is a rigid carrier, and the material of the rigid carrier is selected from any one of sapphire, glass, and hard plastic plate.

[0011] In one embodiment, the light transmittance of the carrier is greater than 85%.

[0012] In one embodiment, the thickness of the carrier plate is ≥5 mm.

[0013] In one embodiment, the roughness Sa of the groove surface of the carrier is 0.02 μm to 0.5 μm.

[0014] The present invention also provides a laser printing device, which uses the carrier plate.

[0015] The present invention further proposes a laser printing method, wherein the laser printing method uses the carrier plate and comprises the following steps:

[0016] S1, sending the carrier plate to the filling station through the transmission device, and filling the printing paste into the groove of the carrier plate by using the filling module;

[0017] S2, sending the carrier plate to the printing station through the transmission device, laying the carrier plate flat with the groove of the carrier plate facing downward, laying the solar cell flat and placing it directly under the carrier plate;

[0018] S3, starting a first laser emitter located above the carrier to perform laser printing, so that the printing paste in the groove falls onto the surface of the solar cell under the action of the laser beam emitted by the first laser emitter to form a grid line pattern;

[0019] S4, sending the carrier plate after laser printing in step S3 to a cleaning station through a transmission device, cleaning the residual printing slurry on the carrier plate, and completing a laser printing cycle.

[0020] In one embodiment, in the step S2, the distance between the carrier board and the solar cell is adjusted to 20 μm to 50 μm.

[0021] In one embodiment, in step S3, the wavelength of the laser beam emitted by the first laser emitter is 355nm-2000nm.

[0022] In one embodiment, in step S3, the laser beam emitted by the first laser emitter includes any one of a long-wave laser, a short-wave laser, and a long-short-wave composite laser.

[0023] In one embodiment, in step S3, the light spot of the laser beam emitted by the first laser emitter onto the surface of the carrier is a shaped light spot, wherein the shaping method includes at least one of a diffraction element DOE, a refractive element ROE, a microlens array, a spherical / aspherical mirror group, a spatial light modulator, and a cylindrical mirror.

[0024] In one embodiment, in step S3, the spot of the laser beam emitted by the first laser emitter onto the surface of the carrier is a homogenized spot, and the size of the spot is 100 μm*100 μm to 500 μm*500 μm.

[0025] In one embodiment, in step S4, the cleaning station includes a laser cleaning device, and the laser cleaning device includes a solvent pool, a second laser emitter disposed above the solvent pool, and an ultrasonic vibration source disposed at the bottom of the solvent pool; in step S4, the carrier is immersed in the solvent of the solvent pool, and the ultrasonic vibration source and the second laser emitter are started at the same time, so that the laser emitted by the second laser emitter hits the groove of the carrier to clean the residual printing slurry on the carrier.

[0026] The technical solution of the present invention designs a rigid carrier plate for laser printing with arched grooves, and combines a shaped light spot and a laser of a special wavelength to make the printing paste in the grooves of the rigid carrier plate easier to desorb, thereby eliminating the need to add a release layer in the carrier plate grooves or increase the content of organic release components in the printing paste to promote the desorption of the printing paste; at the same time, the carrier plate of the present invention has strong rigidity, good wear resistance, high light transmittance and low thermal expansion coefficient, and is used to print a grid line with a lower width, a larger aspect ratio and a higher quality when combined with the laser printing method of the present invention, thereby greatly improving production efficiency and production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0028] Figure 1 It is a partial structural schematic diagram of a carrier board in one embodiment of the present invention;

[0029] Figure 2 is a schematic diagram of a laser cleaning device in one embodiment of the present invention;

[0030] Figure 3 is a schematic diagram of a laser cleaning method in one embodiment of the present invention;

[0031] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings.

[0033] 1. Carrier plate; 11. Groove; 111. Arched portion; 112. Side wall portion; 2. Solvent pool; 3. Ultrasonic vibration source; 4. Second laser emitter. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0036] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0037] Laser printing is a technology that uses laser to irradiate metal slurry carried on a transparent carrier, causing the metal slurry to fall off from the grooves of the carrier and then transfer to the solar cell to form a grid line electrode. However, in the prior art, in order to make the slurry fall off smoothly and take into account the needs of energy saving, the carriers used are mostly flexible materials or rigid and flexible combined materials. On the one hand, they can be reused a small number of times, have a short lifespan, and need to be replaced frequently. On the other hand, flexible materials or rigid materials with low hardness are easy to deform after multiple laser irradiations, and the flatness of the carrier will also change, resulting in technical problems such as broken grids and bent grid lines during laser printing, which not only increases production costs but also affects production efficiency.

[0038] In order to solve the above technical problems, a laser printing technology is developed to improve the aspect ratio of printed grid lines, reduce the line resistance of the grid lines, and reduce production costs and improve production efficiency.

[0039] The present invention provides a carrier board, which includes: at least one groove, which is arranged on the surface of the same side of the carrier board in a specified pattern and contains printing paste, and the printing paste can be released to the surface of a solar cell under laser irradiation.

[0040] It should be noted that the carrier in the present invention is mainly used for laser printing technology. Laser printing is also called laser transfer. The printing slurry is scraped on the surface of the side of the carrier with the groove, and then the carrier is irradiated with a laser. The thermal effect of the laser is used to heat and vaporize the organic components in the slurry, and a high-pressure steam layer is formed at the interface where the slurry / groove contacts. Under the combined action of steam pressure and gravity, the printing slurry overcomes the adhesive force between the interfaces and falls off, and the slurry is transferred to the surface of the object to be transferred.

[0041] In one embodiment, the groove includes at least one of an arched groove, a square groove, a rectangular groove, a semicircular groove, a fan-shaped groove and a triangular groove.

[0042] It should be noted that the arched groove, square groove, rectangular groove, semicircular groove, fan-shaped groove and triangular groove all refer to the shape of the longitudinal section of the groove. The morphology of the groove has a high similarity with the morphology of the gate line to be transferred. When making the groove, it is particularly necessary to refer to the aspect ratio of the gate line to be transferred.

[0043] In one embodiment, the groove is an arched groove.

[0044] It should be noted that the grooves of the carrier in the prior art mainly include square grooves, rectangular grooves, semicircular grooves, fan-shaped grooves, U-shaped grooves and triangular grooves, while in the present invention, arched grooves are used ingeniously. On the one hand, when using square grooves, rectangular grooves and triangular grooves, the bottom of the groove forms a vertex angle with the side wall of the groove, and the width at the vertex angle is usually small, while the diameter of most metal particles in the printing paste is only 1μm to 3μm. With the repeated use of the carrier, the slurry is easily accumulated at the vertex angle of the groove and continues to increase, which can easily cause the printed grid line to deform or the carrier to be scrapped. On the other hand, when using a U-shaped groove, the air pressure caused by the heat vaporization of the organic components in the printing slurry will squeeze the printing slurry laterally, increase the friction between the printing slurry and the vertical groove sidewalls, and hinder the smooth shedding of the slurry, resulting in the need to add a release layer in the carrier groove or increase the content of organic release components in the printing slurry to promote the desorption of the printing slurry.

[0045] In one embodiment, referring to Figure 1 The groove 11 is an arched groove 11, which includes an arched portion 111 and a sidewall portion 112, wherein the angle of the arc of the arched portion 111 is 15 degrees to 180 degrees, and the span a of the arched portion is 5μm to 70μm; the groove width c of the sidewall portion 112 is 5μm to 80μm, and the depth b of the sidewall portion 112 is 5μm to 25μm.

[0046] It should be noted that the groove of the carrier in the present invention is an arched groove, the bottom of the groove is an arched part, and its cross-section is a circular arc, the angle of the circular arc is 15 degrees to 180 degrees (the angle of the circular arc refers to the size of the central angle of the circular arc at the center of the circle), and the side wall part is trumpet-shaped, which can effectively disperse the air pressure received by the printing paste in the groove and push the printing paste to move downward; the arched structure is conducive to releasing the surrounding air pressure received by the printing paste in one direction, reducing lateral friction, and the arched structure also increases the laser irradiation area of ​​the printing paste in the groove, the slurry heats up faster, and the desorption speed is also faster. It should also be noted that the present invention limits the angle of the circular arc of the arched part of the groove, the span of the arched part, and the groove width and depth of the side wall part, so that the groove of the carrier is more consistent with other parameters in the laser printing method of the present invention, thereby promoting the desorption of the printing paste and the improvement of the grid line quality and the improvement of production efficiency to the greatest extent.

[0047] In one embodiment, the carrier is used to print the main grid, and the arched groove 11 includes an arched portion 111 and a sidewall portion 112, wherein the angle of the arc of the arched portion 111 is 15 degrees to 180 degrees, and the span a of the arched portion 111 is 15μm to 70μm; the groove width c of the sidewall portion 112 is 15μm to 80μm, and the depth b of the sidewall portion 112 is 5μm to 25μm.

[0048] In one embodiment, the carrier is used for printing fine grids, and the arched groove 11 includes an arched portion 111 and a sidewall portion 112, wherein the angle of the arc of the arched portion 111 is 15 degrees to 180 degrees, and the span a of the arched portion 111 is 5μm to 20μm; the groove width c of the sidewall portion 112 is 5μm to 25μm, and the depth b of the sidewall portion 112 is 8μm to 20μm.

[0049] It should be noted that the main functions of the main gate and the fine gate are different, so the ranges of the aspect ratios are also different. Correspondingly, the ranges of the aspect ratios of the grooves of the printed main gate and the fine gate are also different.

[0050] In one embodiment, the carrier is a rigid carrier, and the material of the rigid carrier is selected from any one of glass and hard plastic board. It should be noted that the carrier is a light-transmitting rigid carrier. By using a rigid carrier, it can be ensured that the carrier filled with slurry will not deform or deform slightly during the transfer process, further improving the yield of the manufactured structure; at the same time, it is also necessary to improve the light transmittance of the carrier, so that at least most of the transfer laser can pass through the carrier and at least act on the printing slurry out of the groove, so that the printing slurry can quickly leave the groove and print on the surface of the solar cell.

[0051] In a preferred embodiment, the carrier plate is a rigid carrier plate, and the material of the rigid carrier plate is selected from tempered glass.

[0052] It should be noted that the tempered glass is a tempered glass with high transmittance and low reflectivity, and the transmittance of the tempered glass is above 90% and the reflectivity is below 5%; in addition, the tempered glass also has a low optical distortion rate, which can ensure that the light will not produce excessive refraction and scattering when penetrating the carrier, so that the laser beam hitting the printing paste in the groove has high optical uniformity while maintaining high energy, so that all parts of the printing paste are evenly heated. The tempered glass used for the rigid carrier in the present invention also has high strength, high hardness and scratch resistance. Compared with conventional carriers, the rigid carrier in the present invention will not cause irreversible deformation due to repeated scratching of the scraper after multiple fillings; in addition, the tempered glass used for the rigid carrier in the present invention also has good thermal stability and impact resistance, can withstand temperature changes from 150°C to 320°C in a short time, can withstand long-term laser irradiation without damage, and has a long service life.

[0053] It should also be noted that during laser printing, the gap between the carrier board and the solar cell needs to be precisely controlled. If the gap is too large, it will cause problems such as line bending, broken grid and slurry splashing. If the gap is too small, the gas pressure in the groove cannot be released in time, and the slurry grid line will be flattened by the gas pressure in the groove.

[0054] In one embodiment, the light transmittance of the carrier board is greater than 85%. Optionally, the light transmittance of the carrier board can be any one of 86%, 90%, 92%, 95%, 98%, and 99%, as long as it meets the above light transmittance range requirements.

[0055] In one embodiment, the thickness of the carrier is ≥5 mm. It is understandable that the strength of the rigid carrier is ensured to be high enough by limiting the thickness of the carrier to a minimum of 5 mm. When the carrier is not thick enough, it is easy to deform after multiple scrapings, resulting in increased flatness and reduced quality of printed grid lines.

[0056] In one embodiment, the roughness Sa of the groove surface of the carrier is 0.02 μm-0.5 μm.

[0057] The present invention also provides a laser printing device, which uses the carrier plate.

[0058] The present invention further proposes a laser printing method, wherein the laser printing method uses the carrier plate and comprises the following steps:

[0059] S1, sending the carrier plate to the filling station through the transmission device, and filling the printing paste into the groove of the carrier plate by using the filling module;

[0060] S2, sending the carrier plate to the printing station through the transmission device, laying the carrier plate flat with the groove of the carrier plate facing downward, laying the solar cell flat and placing it directly under the carrier plate;

[0061] S3, starting a first laser emitter located above the carrier to perform laser printing, so that the printing paste in the groove falls onto the surface of the solar cell under the action of the laser beam emitted by the first laser emitter to form a grid line pattern;

[0062] S4, sending the carrier plate after laser printing in step S3 to a cleaning station through a transmission device, cleaning the residual printing slurry on the carrier plate, and completing a laser printing cycle.

[0063] It should be noted that the laser printing method of the present invention includes a complete cycle of filling, printing and cleaning. The carrier after this cycle can be directly used for the production of the next cycle. Therefore, in order to ensure the production efficiency of laser printing, each step must be strictly controlled. In the printing step, the main consideration is that the carrier is not easy to deform and the quality of the printed grid lines. In the cleaning step, the consideration is the complete cleaning of the residual slurry on the carrier. At the same time, it is also necessary to ensure that the cleaning time can meet the production rhythm and does not slow down the production rhythm.

[0064] It should also be noted that the laser printing method in the present invention is a non-contact printing technology that can improve the fine grid printing process of high-efficiency solar cells, break through the line width limit of traditional screen printing, and easily achieve a line width of less than 15um, thereby being able to print ultra-fine grid lines with a larger aspect ratio on the cell, helping solar cells to achieve ultra-fine dense grid cells, matching selective emitter technology, and improving the efficiency of solar cells while significantly saving 30% to 60% of slurry consumption, ultimately reducing battery production costs and power generation costs.

[0065] In one embodiment, in the step S2, the distance between the carrier board and the solar cell is adjusted to 20 μm to 50 μm.

[0066] It should be noted that during laser printing, the spacing or interval between the substrate and the solar cell needs to be precisely controlled. If the spacing is too large, the uncertainty will increase, which will lead to problems such as line bending, broken grids, and slurry splashing. If the spacing is too small, the gas pressure in the groove will impact the grid line, and the slurry grid line will be flattened by the gas pressure in the groove. By controlling the flatness and rigidity of the substrate, the spacing between the substrate and the solar cell can be better controlled, thereby widening the process window and improving the yield of laser printing.

[0067] In one embodiment, in step S3, the wavelength of the laser beam emitted by the first laser emitter is 355nm-2000nm.

[0068] In one embodiment, in step S3, the laser beam emitted by the first laser emitter includes any one of a long-wave laser, a short-wave laser, and a long-short-wave composite laser.

[0069] It should be noted that the inventors have analyzed the absorption spectra of commonly used photovoltaic printing pastes and found that the organic components in the paste have poor absorption of long waves and higher absorption rate of short-wave light energy. For short-wave lasers, such as 355nm lasers, lower laser power can be used to quickly gasify the organic components in the paste, thereby generating sufficient gas pressure in a short time, so that it can fall off from the groove; but short-wave lasers are prone to laser damage to the SiN layer on the surface of the solar cell, and the homogenization effect of the light spot is more stringent. Long-wave lasers, such as near-infrared lasers, require higher laser power to generate sufficient gas pressure in the paste, but since the solar cell has a low absorption rate of near-infrared laser light energy, near-infrared lasers are not easy to damage the cell. Therefore, in the present invention, long-wave lasers can be used alone, short-wave lasers can be used alone, or composite lasers of long and short wavelengths can be used, so that the paste can be more easily removed from the groove.

[0070] In one embodiment, in step S3, the spot of the laser beam emitted by the first laser emitter onto the surface of the carrier is a shaped spot, wherein the shaping method includes at least one of a diffraction element DOE, a refraction element ROE, a microlens array, a spherical / aspherical mirror group, a spatial light modulator, and a cylindrical mirror. It should be noted that, through the shaping of the laser spot, a homogenized spot can be obtained, and the energy of the spot is more balanced.

[0071] In one embodiment, in step S3, the light spot emitted by the laser beam emitted by the first laser emitter onto the surface of the carrier is a homogenized light spot, and the size of the light spot is 100 μm*100 μm to 500 μm*500 μm.

[0072] It should be noted that after the laser beam emitted by the first laser emitter is shaped by the above-mentioned shaping method, a large-sized uniform light spot can be formed on the surface of the carrier. On the one hand, the large-sized uniform light spot can reduce the alignment accuracy between the laser and the groove, and the requirements for the first laser emitter are lower, which can further save the equipment cost of the laser printing device; on the other hand, the large-sized uniform light spot can be combined with the arched grooves with specific structures and specific sizes on the carrier of the present invention, which can stably and evenly heat the printing paste in the grooves, and generate uniform, stable and downward air pressure around the printing paste, thereby pushing the printing paste to move downward and desorb from the grooves, and allowing the paste to quickly fall onto the surface of the solar cell and keep its shape intact.

[0073] In one embodiment, the viscosity of the printing paste is 1-350 Pa·s.

[0074] In one embodiment, in the printing paste, the weight ratio of the metal particles in the paste is 87-94wt%.

[0075] In one embodiment, the printing paste can be a customized paste with better plasticity and rheology, and is also compatible with the paste used in traditional screen printing, including aluminum-containing silver paste, aluminum-free silver paste, silver-coated copper paste, copper paste and other conductive pastes whose main components are metal particles.

[0076] It should also be noted that in order to improve the desorption of the printing paste from the grooves of the carrier board in the prior art, a release layer is usually added to the grooves or the content of organic release components is increased in the printing paste to enhance the desorption ability. The inventors found through relevant experiments on the above two methods that adding a release layer in the grooves not only adds a process of coating the release layer in the laser printing process, but also the amount and uniformity of the coating release layer are difficult to control, and the residue on the grating electrode is also difficult to clean; although increasing the content of organic release components in the printing paste allows the printing paste to desorb quickly, it may cause the organic release component content to be too high, resulting in excessive pressure of the gas released after gasification, causing the printed grid electrode to be deformed by the gas pressure released in the grooves; in addition, increasing the content of organic release components in the printing paste to be too high will also cause the printed grid electrode to contain excessive amounts of non-volatile organic release components, which greatly reduces the density of the grid electrode after curing, thereby increasing its internal resistance, resulting in low photoelectric conversion efficiency and shortened service life of the solar cell. In the present invention, by using a carrier plate containing a special arch structure and grooves of a certain size, a shaped uniform light spot of a certain size, and a laser of a certain wavelength, the slurry can be made to fall off from the grooves more easily. There is no need to add an additional release layer or change the slurry formula, and there is no need to introduce additional consumables. The production cost is significantly reduced and the applicability is wider.

[0077] In one embodiment, the cleaning station includes a laser cleaning device, referring to Figure 2 The laser cleaning device includes a solvent pool 2, a second laser emitter 4 arranged above the solvent pool and an ultrasonic vibration source 3 arranged at the bottom of the solvent pool; in the step S4, the carrier 1 is immersed in the solvent of the solvent pool 2, and the ultrasonic vibration source 3 and the second laser emitter 4 are started at the same time, so that the laser emitted by the second laser emitter 4 hits the groove 11 of the carrier 1 to clean the residual printing paste on the carrier 1.

[0078] It can be understood that in the step S4, after the carrier 1 arrives at the cleaning station, a second laser emitter 4, a carrier 1 to be cleaned, a solvent pool 2, and an ultrasonic vibration source 2 are sequentially arranged from top to bottom.

[0079] In one embodiment, the emission power of the second laser emitter is 100-2000W, the emission wavelength of the second laser emitter is 355-2000nm, and the vibration frequency of the ultrasonic vibration source is 80-200kHz.

[0080] In one embodiment, the laser printing method is applicable to all solar cell preparation routes, including but not limited to PERC, TOPCon, HJT, BC and stacked cells.

[0081] In one embodiment, the grid lines obtained by the laser printing method include any one of a front main grid, a front fine grid, a back main grid and a back fine grid.

[0082] In one embodiment, during the laser printing process, the carrier grooves can correspond to the battery cell grid line patterns one by one or at intervals, so that after coating the slurry once on a carrier, more than two battery cells can be printed continuously through laser selective printing, realizing single-coating multi-piece printing, reducing the process flow and improving production capacity.

[0083] In one embodiment, during the cleaning process of step S4, the depth of immersion of the carrier in the solvent is 0.1mm-2mm; the distance between the laser emitter and the carrier is 270mm-600mm; the distance between the ultrasonic source and the carrier is 30mm-200mm; the width of the light spot output by the laser emitter on the carrier is 30μm-10mm. It can be understood that in step S4 of the laser printing method of the present invention, by combining laser impact, solvent dissolution and ultrasonic vibration, and combining the specific shape of the carrier for laser transfer and the location of the residual slurry to reasonably control the specific parameters of the relevant device or equipment, the carrier can be cleaned in a very short time, meeting the requirements of the online cleaning solution, and there is no need to stop the line during the cleaning process.

[0084] The present invention is further described below by means of specific embodiments:

[0085] The raw materials used in the embodiments of the present invention are all commercially available, and the present invention does not impose any restrictions on the sources of the raw materials.

[0086] Example 1

[0087] The grooves of the carrier in Example 1 are arched grooves. The specific parameters of the carrier used for printing the main grid are as follows:

[0088] The angle of the arc of the arched portion is 66 degrees, the span of the arched portion is 40 μm, the depth of the sidewall portion is 5 μm, the minimum groove width of the sidewall portion is 40 μm, and the maximum groove width of the sidewall portion is 48 μm.

[0089] The grooves of the carrier in Example 1 are arched grooves. The specific parameters of the carrier used for printing fine grids are as follows:

[0090] The angle of the arc of the arched portion is 135 degrees, the span of the arched portion is 6 μm, the depth of the sidewall portion is 14 μm, the minimum groove width of the sidewall portion is 6 μm, and the maximum groove width of the sidewall portion is 10 μm.

[0091] The material of the carrier used in Example 1 is tempered glass, B270 type glass purchased from Schott AG, with a thickness of about 6 mm, and the roughness Sa value of the groove surface of the carrier is 0.2 μm.

[0092] In Example 1, the printing paste is an aluminum-free silver paste, the particle size of the metal particles is about 90wt%, and the viscosity of the printing paste is 90Pa.s.

[0093] The laser printing method in Example 1 comprises the following steps:

[0094] S1, sending the carrier plate to the filling station through the transmission device, and filling the printing paste into the groove of the carrier plate by using the filling module;

[0095] S2, sending the carrier plate to the printing station through the transmission device, laying the carrier plate flat with the groove of the carrier plate facing downward, laying the solar cell flat and placing it directly under the carrier plate;

[0096] S3, starting a first laser emitter located above the carrier to perform laser printing, so that the printing paste in the groove falls onto the surface of the solar cell under the action of the laser beam emitted by the first laser emitter to form a grid line pattern;

[0097] S4, sending the carrier plate after laser printing in step S3 to a cleaning station through a transmission device, cleaning the residual printing slurry on the carrier plate, and completing a laser printing cycle.

[0098] The laser printing method in Example 1 is as follows Figure 3 The schematic diagram in Figure 3 The left side in the middle is a schematic diagram of the carrier being filled at the filling station, and the right side is a schematic diagram of the printing station being printed.

[0099] The step S2 refers to Figure 3 On the right side of the solar cell, the distance between the carrier board and the solar cell is adjusted to 30 μm.

[0100] In the step S3, the wavelength of the first laser emitter used in Example 1 is 532 nm, and the spot of the laser beam emitted by the first laser emitter that is projected onto the surface of the carrier is a homogenized spot with a size of 100 μm*100 μm.

[0101] In step S4, refer to Figure 2 In step S4, the carrier board 1 is immersed in the solvent of the solvent pool 2, and the ultrasonic vibration source 3 and the second laser emitter 4 are started at the same time, so that the laser emitted by the second laser emitter 4 hits the groove 11 of the carrier board 1 to clean the residual printing paste on the carrier board 1.

[0102] In the step S4, the emission power of the second laser emitter is 100 W, the emission wavelength of the second laser emitter is 532 nm, and the vibration frequency of the ultrasonic vibration source is 200 kHz.

[0103] During the cleaning process of step S4, the depth of immersion of the carrier in the solvent is 0.5 mm; the distance between the laser emitter and the carrier is 400 mm; the distance between the ultrasonic vibration source and the carrier is 60 mm; the light spot output by the laser emitter on the carrier is a homogenized light spot with a width of about 80 μm.

[0104] The solar cell was produced in Example 1.

[0105] After testing, the grid line width of the main grid of the solar cell prepared in Example 1 is 45.2μm to 47.7μm; the grid line width of the fine grid of the solar cell prepared in Example 1 is within 10μm; the grid line morphology of the main grid and the fine grid is good, and there is no bending, deformation or collapse.

[0106] Example 2

[0107] The material of the carrier plate used in Example 2 is tempered glass, B270 type glass purchased from Schott AG.

[0108] Embodiment 2 is based on Embodiment 1, and the difference is that the parameters of the carrier groove in Embodiment 2 are different, as follows:

[0109] The grooves of the carrier in Example 2 are arched grooves. The specific parameters of the carrier used for printing the main grid are as follows:

[0110] The angle of the arc of the arched portion is 66 degrees, the span of the arched portion is 22 μm, the depth of the sidewall portion is 5 μm, the minimum groove width of the sidewall portion is 22 μm, and the maximum groove width of the sidewall portion is 28 μm.

[0111] The grooves of the carrier in Example 2 are arched grooves. The specific parameters of the carrier used for printing fine grids are as follows:

[0112] The angle of the arc of the arched portion is 135 degrees, the span of the arched portion is 8 μm, the depth of the sidewall portion is 14 μm, the minimum groove width of the sidewall portion is 8 μm, and the maximum groove width of the sidewall portion is 12 μm.

[0113] Example 2 was used to produce a solar cell.

[0114] After testing, the grid line width of the main grid of the solar cell produced in Example 2 is 23.8μm ~ 26.5μm; the grid line width of the multiple segments of fine grids of the solar cell produced in Example 2 is within 10μm, and only a few are slightly larger than 10μm; the grid line morphology of the main grid and fine grid is good, and there is no bending, deformation or collapse.

[0115] In summary, the grid line electrodes in the solar cell produced by the carrier, laser printing device and laser printing method of the present invention have good morphology, the printed grid lines are not easy to bend, deform or collapse, and the width can reach within 10μm, which can improve the photoelectric conversion efficiency to a certain extent.

[0116] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A carrier board, characterized in that: The carrier board comprises: At least one groove is arranged on the surface of the same side of the carrier in a designated pattern and contains printing paste, and the printing paste can be released to the surface of the solar cell under laser irradiation.

2. The carrier board according to claim 1, characterized in that: The grooves include at least one of arched grooves, square grooves, rectangular grooves, semicircular grooves, fan-shaped grooves and triangular grooves.

3. The carrier board according to claim 1, characterized in that: The groove is an arched groove, and the arched groove includes an arched portion and a sidewall portion, wherein: The angle of the arc of the arched portion is 15 to 180 degrees, and the span of the arched portion is 5 μm to 70 μm; The groove width of the side wall portion is 5 μm to 80 μm, and the depth of the side wall portion is 5 μm to 25 μm.

4. The carrier board according to claim 3, characterized in that: The carrier is used for printing a main grid, and the arched groove includes an arched portion and a side wall portion, wherein the arc angle of the arched portion is 15 to 180 degrees, and the span of the arched portion is 15 μm to 70 μm; the groove width of the side wall portion is 15 μm to 80 μm, and the depth of the side wall portion is 5 μm to 25 μm; And / or, the carrier is used for printing fine grids, and the arched groove includes an arched portion and a sidewall portion, wherein the angle of the arc of the arched portion is 15 degrees to 180 degrees, and the span of the arched portion is 5μm to 20μm; the groove width of the sidewall portion is 5μm to 25μm, and the depth of the sidewall portion is 8μm to 20μm.

5. The carrier board according to claim 1, characterized in that: The carrier plate is a rigid carrier plate, and the material of the rigid carrier plate is selected from any one of glass and hard plastic plate; And / or, the light transmittance of the carrier board is greater than 85%; And / or, the thickness of the carrier plate is ≥5 mm; And / or, the roughness Sa of the groove surface of the carrier is 0.02 μm to 0.5 μm.

6. A laser printing device, characterized in that: The laser printing device uses the carrier plate described in claims 1 to 5.

7. A laser printing method, characterized in that: The laser printing method uses the carrier plate according to claims 1 to 5, and the laser printing method comprises the following steps: S1, sending the carrier plate to the filling station through the transmission device, and filling the printing paste into the groove of the carrier plate by using the filling module; S2, sending the carrier plate to the printing station through the transmission device, laying the carrier plate flat with the groove of the carrier plate facing downward, laying the solar cell flat and placing it directly under the carrier plate; S3, starting a first laser emitter located above the carrier to perform laser printing, so that the printing paste in the groove falls onto the surface of the solar cell under the action of the laser beam emitted by the first laser emitter to form a grid line pattern; S4, sending the carrier plate after laser printing in step S3 to a cleaning station through a transmission device, cleaning the residual printing slurry on the carrier plate, and completing a laser printing cycle.

8. The laser printing method according to claim 7, characterized in that: In the step S2, the distance between the carrier board and the solar cell is adjusted to 20 μm to 50 μm.

9. The laser printing method according to claim 7, characterized in that: In step S3, the wavelength of the laser beam emitted by the first laser emitter is 355nm to 2000nm; And / or, in step S3, the laser beam emitted by the first laser emitter includes any one of a long-wave laser, a short-wave laser, and a long-short-wave composite laser; And / or, in the step S3, the light spot emitted by the laser beam emitted by the first laser emitter onto the surface of the carrier is a shaped light spot, wherein the shaping method includes at least one of a diffraction element DOE, a refraction element ROE, a microlens array, a spherical / aspherical mirror group, a spatial light modulator, and a cylindrical mirror; And / or, in the step S3, the light spot of the laser beam emitted by the first laser emitter onto the surface of the carrier is a homogenized light spot, and the size of the light spot is 100 μm*100 μm to 500 μm*500 μm.

10. The laser printing method according to claim 7, characterized in that: In the step S4, the cleaning station includes a laser cleaning device, and the laser cleaning device includes a solvent pool, a second laser emitter disposed above the solvent pool, and an ultrasonic vibration source disposed at the bottom of the solvent pool; In the step S4, the carrier is immersed in the solvent of the solvent pool, and the ultrasonic vibration source and the second laser emitter are started at the same time, so that the laser emitted by the second laser emitter hits the groove of the carrier to clean the residual printing paste on the carrier.

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