Laser cutting and passivating method for silicon heterojunction solar cell

Abstract

A laser cutting and passivating method for a silicon heterojunction solar cell (10), comprising: first performing laser grooving positioning on a surface to be cut of the silicon heterojunction solar cell (10) to form at least one pair of grooves: a first cutting positioning groove (11) and a second cutting positioning groove (12) which are provided opposite to each other; and then, along a line connecting the first cutting positioning groove (11) and the second cutting positioning groove (12), performing laser cutting on said surface, and performing solution spraying passivation treatment on an area irradiated by a laser. The method simultaneously performs laser cutting and passivation treatment, and while improving the photoelectric conversion efficiency of the solar cell by successfully passivating the cut position, the method also simplifies the technological process and improves the production efficiency.

Description

A method for laser cutting and passivation of silicon heterojunction solar cells Technical Field

[0001] The present invention relates to the technical field of solar cells, and more particularly to a method for laser cutting and passivation of silicon heterojunction solar cells. Background Art

[0002] Against the backdrop of carbon peak and carbon neutrality, the development of new technologies for photovoltaic modules is crucial, as it can effectively improve the power generation efficiency, reliability, and cost of photovoltaic systems. Amorphous silicon / crystalline silicon heterojunction solar cells (hereinafter referred to as "silicon heterojunction solar cells") utilize an amorphous silicon thin film deposited on crystalline silicon. Combining the advantages of both crystalline silicon and thin-film cells, they offer a simple structure, low process temperatures, excellent passivation, high open-circuit voltage, excellent temperature characteristics, and bifacial power generation. They are a hot topic in the development of high-conversion-efficiency silicon-based solar cells.

[0003] Half-cell and shingled modules are relatively new technologies in the module industry. Developing reliable half-cells while reducing costs is a hot topic for both companies and research institutions. Both technologies require separating solar cells into half-cells, an effective approach to achieving higher-performance photovoltaic modules. Compared to full-size cells, half-cells generate lower current, resulting in lower losses. Therefore, the development of a half-cell process that minimizes defects is increasingly important for furthering the application of half-cell processing in mass production of photovoltaic modules. Among the various slicing and separation technologies, laser cutting has become the mainstream process in the market today due to its simplicity, low cost, and minimal losses. During the cutting process, laser damage and mechanical fracture zones form on the cut edges of the cell, necessitating passivation of these cut edges to reduce defect density. Technical issues

[0004] However, existing passivation methods require high temperatures to form a passivation layer on the surface of silicon heterojunction solar cells. High temperatures can severely damage the thin film structure of silicon heterojunction solar cells, significantly reducing their efficiency. Currently, most methods use solution passivation for cut surface passivation. However, these methods typically require a two-step process of "acid solution cleaning followed by passivation solution passivation" after the cell is cut and split, significantly increasing the complexity of the process and production costs.

[0005] It can be seen that developing a simple and low-cost method for laser cutting and passivation of silicon heterojunction solar cells has become one of the important technical problems that need to be solved urgently in the field of silicon heterojunction solar cells. Technical Solutions

[0006] In view of this, the present invention provides a method for laser cutting and passivation of silicon heterojunction solar cells, which effectively solves the technical problems existing in the prior art. Laser cutting and passivation treatment are performed simultaneously. On the basis of ensuring successful passivation of the cut parts and improving the photoelectric conversion efficiency of the solar cells, the process flow is simplified and production efficiency is improved.

[0007] To achieve the above objectives, the present invention provides the following technical solutions:

[0008] A method for laser cutting and passivation of silicon heterojunction solar cells, comprising:

[0009] Providing a silicon heterojunction solar cell;

[0010] Performing laser grooving and positioning on the surface to be cut of the silicon heterojunction solar cell to form at least one pair of first cutting positioning grooves and second cutting positioning grooves that are oppositely arranged, wherein the surface to be cut is the front surface or the back surface of the silicon heterojunction solar cell;

[0011] The surface to be cut is laser cut along the line connecting the first cutting positioning groove and the second cutting positioning groove, and the laser-irradiated area is simultaneously subjected to a solution spray passivation treatment, wherein the cut portion of the surface to be cut is naturally cracked by the heat of the laser irradiation and the cooling of the solution spray.

[0012] Optionally, the laser irradiated area is subjected to a solution spray passivation treatment, including:

[0013] The laser irradiated area is subjected to a solution spray passivation treatment using a passivation solution, so that the passivation solution and the silicon at the cutting portion of the surface to be cut undergo a chemical reaction and passivation.

[0014] Optionally, the chemical reaction passivation includes coordination of groups in the passivation solution with unsaturated dangling bonds of silicon.

[0015] Optionally, the passivation solution is a solution of aminosulfonic acid dissolved in deionized water;

[0016] The concentration of the solution of sulfamic acid dissolved in the deionized water is 5%-10%;

[0017] Furthermore, the temperature of the passivation solution is 10-20°C.

[0018] Optionally, performing laser cutting on the surface to be cut includes:

[0019] The laser spot size of the laser is adjusted to a range of 30-100 μm, and the surface to be cut is laser cut.

[0020] Optionally, performing laser cutting on the surface to be cut includes:

[0021] The rated power of the laser is adjusted to a range of 10-30 W, and the surface to be cut is laser cut.

[0022] Optionally, performing laser cutting on the surface to be cut includes:

[0023] The laser engraving speed of the laser is adjusted to 3000-5000 mm / s, and the surface to be cut is laser cut.

[0024] Optionally, laser grooving and positioning is performed on the surface to be cut of the silicon heterojunction solar cell, including:

[0025] The size of the laser spot of the laser is adjusted to a range of 30-200 μm, and the surface to be cut of the silicon heterojunction solar cell is laser grooved and positioned.

[0026] Optionally, laser grooving and positioning is performed on the surface to be cut of the silicon heterojunction solar cell, including:

[0027] The rated power range of the laser is adjusted to 20-50W, and the laser groove positioning is performed on the surface to be cut of the silicon heterojunction solar cell.

[0028] Optionally, laser grooving and positioning is performed on the surface to be cut of the silicon heterojunction solar cell, including:

[0029] The laser engraving speed of the laser is adjusted to 1500-3000 mm / s, and the surface to be cut of the silicon heterojunction solar cell is laser grooved and positioned. Beneficial effects

[0030] Compared with the existing technology, the technical solution provided by the present invention has at least the following advantages:

[0031] The present invention provides a method for laser cutting and passivation of silicon heterojunction solar cells, comprising: providing a silicon heterojunction solar cell; performing laser grooving and positioning on a surface to be cut of the silicon heterojunction solar cell to form at least one pair of first cutting positioning grooves and second cutting positioning grooves arranged opposite to each other, wherein the surface to be cut is the front surface or the back surface of the silicon heterojunction solar cell; performing laser cutting on the surface to be cut along a line connecting the first cutting positioning groove and the second cutting positioning groove, and simultaneously performing a solution spray passivation treatment on the laser irradiated area, wherein the cut portion of the surface to be cut is naturally split by the heat of the laser irradiation and the cooling of the solution spray.

[0032] As can be seen from the foregoing, the technical solution provided by the present invention first forms two opposing cutting positioning grooves on a silicon heterojunction solar cell, and then performs a subsequent laser cutting step. This significantly reduces the cutting damage and thermal impact caused by cutting the silicon heterojunction solar cell during the cutting process, allowing the silicon heterojunction solar cell to self-heat and split due to thermal stress, thereby reducing the efficiency loss of the silicon heterojunction solar cell during cutting. Furthermore, while laser cutting the silicon heterojunction solar cell, the laser-irradiated area is simultaneously passivated by spraying a solution. This not only achieves the purpose of simultaneous laser cutting and passivation treatment, but also achieves the purpose of simultaneous chemical cleaning and passivation treatment of the cut area through solution spraying. This simplifies the process flow and improves production efficiency, while ensuring successful passivation of the cut area and improving the photovoltaic conversion efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0034] FIG1 is a flow chart of a method for laser cutting and passivation of silicon heterojunction solar cells provided by an embodiment of the present invention;

[0035] Figures 2 to 4 are schematic structural diagrams corresponding to the steps in Figure 1;

[0036] FIG5 is a schematic diagram of the coordination between the sulfonic acid groups on the silicon surface at a cut and the unsaturated dangling bonds of silicon provided by an embodiment of the present invention. Best Mode for Carrying Out the Invention

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0038] As described in the background art, existing passivation methods require high temperature conditions to form a passivation layer on the surface of silicon heterojunction solar cells. However, high temperature environments can cause serious damage to the thin film structure of silicon heterojunction solar cells, resulting in a significant decrease in the efficiency of silicon heterojunction solar cells. At present, most methods use solution passivation to passivate the cut surface, but after the cell is cut into pieces, a two-step method of "acid solution cleaning treatment-passivation solution passivation treatment" is adopted, which greatly increases the complexity of the process and production costs. Therefore, the development of a simple and low-cost laser cutting and passivation method for silicon heterojunction solar cells has become one of the important technical problems that need to be solved in the field of silicon heterojunction solar cells.

[0039] Based on this, an embodiment of the present invention provides a method for laser cutting and passivation of silicon heterojunction solar cells, which effectively solves the technical problems existing in the prior art. Laser cutting and passivation treatment are performed simultaneously. On the basis of ensuring successful passivation of the cut parts and improving the photoelectric conversion efficiency of the solar cells, the process flow is simplified and production efficiency is improved.

[0040] To achieve the above objectives, the technical solutions provided by the embodiments of the present invention are as follows. The technical solutions provided by the embodiments of the present invention are described in detail with reference to FIG. 1 to FIG. 5 .

[0041] 1 is a flow chart of a method for laser cutting and passivation of a silicon heterojunction solar cell according to an embodiment of the present invention, wherein the laser cutting and passivation method includes:

[0042] S1. Provide a silicon heterojunction solar cell.

[0043] S2. Perform laser grooving and positioning on the surface to be cut of the silicon heterojunction solar cell to form at least one pair of oppositely arranged first cutting positioning grooves and second cutting positioning grooves, wherein the surface to be cut is the front surface or the back surface of the silicon heterojunction solar cell.

[0044] S3. Laser cutting is performed on the surface to be cut along the line connecting the first cutting positioning groove and the second cutting positioning groove, and the laser-irradiated area is subjected to a solution spray passivation treatment, wherein the cut portion of the surface to be cut is naturally cracked by the heat of the laser irradiation and the cooling of the solution spray.

[0045] It is understandable that the technical solution provided by the embodiment of the present invention first forms two relatively arranged cutting positioning grooves on the silicon heterojunction solar cell, and then performs the subsequent laser cutting step, thereby significantly reducing the cutting damage and thermal impact caused by cutting the silicon heterojunction solar cell during the cutting process, allowing the silicon heterojunction solar cell to self-heat and split due to thermal stress, thereby reducing the efficiency loss of the silicon heterojunction solar cell cutting. In addition, while the silicon heterojunction solar cell is being laser cut, the laser irradiated area is simultaneously passivated by spraying a solution. Thus, not only the purpose of performing laser cutting and passivation treatment simultaneously is achieved, but also the purpose of chemical cleaning treatment and passivation treatment of the cut area is achieved simultaneously by spraying a solution. On the basis of ensuring the successful passivation of the cut area and improving the photovoltaic conversion efficiency of the solar cell, the process flow is simplified and production efficiency is improved. Modes for Carrying Out the Invention

[0046] The technical solution provided by the embodiment of the present invention is described in more detail below in conjunction with the corresponding structural diagram of the process method. Referring to FIG2 , corresponding to step S1 , a silicon heterojunction solar cell 10 is provided.

[0047] In one embodiment of the present invention, the silicon heterojunction solar cell provided in the embodiment of the present invention may be an amorphous silicon heterojunction solar cell or a crystalline silicon heterojunction solar cell, and no specific limitation is imposed on this.

[0048] 3a and 3b , corresponding to step S2 , FIG3b is a cross-sectional view along the AA′ direction in FIG3a , wherein the surface to be cut of the silicon heterojunction solar cell 10 is laser grooved and positioned to form at least one pair of oppositely arranged first cutting positioning grooves 11 and second cutting positioning grooves 12 , wherein the surface to be cut is the front surface or the back surface of the silicon heterojunction solar cell 10 .

[0049] It is understandable that the embodiments of the present invention provide a laser cutting and passivation method that uses laser grooving and positioning technology to induce cracks in silicon heterojunction solar cells and extend the cracks, wherein the extended crack line is the line connecting the first cutting positioning groove and the second cutting positioning groove. Therefore, the embodiments of the present invention provide a laser cutting and passivation method that can reduce the occurrence of hidden cracks and significantly reduce the cutting damage and thermal effects caused by cutting silicon heterojunction solar cells during the cutting process. This allows the silicon heterojunction solar cells to self-crack due to thermal stress, reducing the efficiency loss of silicon heterojunction solar cells during cutting and improving production yield.

[0050] In one embodiment of the present invention, the paired first cutting positioning grooves and the second cutting positioning grooves provided in the embodiment of the present invention can be one pair or multiple pairs to meet the requirements of cutting half a slice or more slices of silicon heterojunction solar cells. Preferably, the paired first cutting positioning grooves and the second cutting positioning grooves provided in the embodiment of the present invention are preferably located at the edges of two opposite sides of the silicon heterojunction solar cell, the connecting line between the paired first cutting positioning grooves and the second cutting positioning grooves is parallel to the gate lines of the silicon heterojunction solar cell, and the shape of the cutting positioning grooves can be rectangular, thereby improving the effect of the laser grooving positioning technology.

[0051] It should be noted that the embodiment of the present invention does not impose any specific restrictions on the depth of the cutting positioning groove, which can be selected as 40-80μm. If the depth of the cutting positioning groove is too deep, such as higher than 80μm, the silicon heterojunction solar cell will automatically crack along with the crack from the cutting positioning groove, thereby making the cut cross-section of the silicon heterojunction solar cell extremely uneven and irregular; if the depth of the cutting positioning groove is too shallow, such as lower than 40μm, the laser grooving positioning technology will not achieve the corresponding effect, and thermal stress natural cracking cannot be achieved at the connection line of the paired first cutting positioning groove and the second cutting positioning groove during subsequent laser cutting, thereby reducing the generation efficiency. Preferably, the depth of the cutting positioning groove can be 60μm, 70μm, etc. In actual applications, the size and shape of the cutting positioning groove formed by laser grooving positioning are related to the silicon heterojunction solar cell and the instruments used in actual operation. This needs to be flexibly designed according to the actual application, and the present invention does not impose any specific restrictions.

[0052] In one embodiment of the present invention, the embodiment of the present invention provides a method for performing laser grooving and positioning on the surface to be cut of a silicon heterojunction solar cell, comprising: adjusting the laser to at least one of a nanosecond red laser, a nanosecond green laser, and a nanosecond violet laser, and performing laser grooving and positioning on the surface to be cut of the silicon heterojunction solar cell.

[0053] Preferably, the embodiment of the present invention may use a nanosecond green laser with a wavelength of 532 nm to perform laser grooving and positioning on the surface to be cut.

[0054] In one embodiment of the present invention, the embodiment of the present invention provides a method for laser grooving and positioning the surface to be cut of a silicon heterojunction solar cell, comprising: adjusting the size of the laser spot of the laser to a range of 30-200 μm, and performing laser grooving and positioning on the surface to be cut of the silicon heterojunction solar cell.

[0055] Preferably, the embodiment of the present invention can adjust the size of the laser spot of the laser to 120 μm, 50 μm, etc., to perform laser grooving and positioning on the surface to be cut.

[0056] In one embodiment of the present invention, the laser grooving and positioning of the surface to be cut of the silicon heterojunction solar cell provided in the embodiment of the present invention includes: adjusting the rated power range of the laser to 20-50W, and performing laser grooving and positioning on the surface to be cut of the silicon heterojunction solar cell.

[0057] Preferably, in the embodiment of the present invention, the rated power of the laser can be adjusted to 30W, 40W, etc., to perform laser grooving and positioning on the surface to be cut.

[0058] In one embodiment of the present invention, the laser grooving and positioning of the surface to be cut of the silicon heterojunction solar cell provided in the embodiment of the present invention includes: adjusting the laser engraving speed of the laser to 1500-3000 mm / s, and laser grooving and positioning the surface to be cut of the silicon heterojunction solar cell.

[0059] Preferably, in the embodiment of the present invention, the laser engraving speed of the laser can be adjusted to 1500-1800 mm / s or 1500-2000 mm / s to perform laser grooving and positioning on the surface to be cut.

[0060] As shown in Figure 4, corresponding to step S3, the surface to be cut is laser cut along the line between the first cutting positioning groove 11 and the second cutting positioning groove 12, and the laser irradiated area is passivated by solution spraying, wherein the cutting part of the surface to be cut is naturally cracked by the heat of laser irradiation and cooling of solution spraying.

[0061] As can be understood, the laser cutting provided by the embodiments of the present invention utilizes low-temperature cutting technology. This eliminates the need for pre-cutting the surface to be cut, such as forming a cut path. Instead, the wafer naturally breaks through the thermal expansion and contraction effects of the heat from the laser irradiation and the cooling effect from the solution spray. This avoids problems such as mechanical cracking and laser-induced high-temperature cracking. With the demand for reducing module costs and improving efficiency, thinner cell slices and smaller cell spacing are increasingly being adopted. The contact force of the solder ribbon on the cut edge of the cell can easily damage the cell, so protecting the cut edge from damage is becoming increasingly important. The embodiments of the present invention utilize low-temperature laser technology, combined with the principle of thermal expansion and contraction, to achieve natural cracking through thermal stress. This results in a smooth cross-section free of microcracks at the cut site, ensuring the cell's mechanical strength is essentially equivalent to that of the entire wafer, minimizing the risk of fragmentation and hidden cracking during module use. Precisely controlled laser heating and localized auxiliary cooling create a large temperature gradient in the silicon wafer, causing thermal stress in the material to reach the fracture threshold and fracture. The crack propagates along the thermal gradient induced by the laser irradiation path, completely separating the material. Preferably, in the embodiment of the present invention, a cutting positioning groove is formed on the surface to be cut, so as to accurately control the direction of the crack and improve the cracking effect.

[0062] In one embodiment of the present invention, the laser cutting of the surface to be cut provided in the embodiment of the present invention includes: adjusting the laser to a red light laser with a wavelength of 1064nm, and laser cutting the surface to be cut, wherein the red light laser includes at least one of a nanosecond laser and a picosecond laser.

[0063] In one embodiment of the present invention, the laser cutting of the surface to be cut provided by the embodiment of the present invention includes: adjusting the laser spot size of the laser to a range of 30-100 μm, and laser cutting the surface to be cut.

[0064] Preferably, in the embodiment of the present invention, the laser spot size of the laser can be adjusted to 50 μm to perform laser cutting on the surface to be cut.

[0065] In one embodiment of the present invention, the laser cutting of the surface to be cut provided by the embodiment of the present invention includes: adjusting the rated power range of the laser to be 10-30W, and laser cutting the surface to be cut.

[0066] Preferably, in the embodiment of the present invention, the rated power of the laser can be adjusted to 20W to perform laser cutting on the surface to be cut.

[0067] In one embodiment of the present invention, the laser cutting of the surface to be cut provided by the embodiment of the present invention includes: adjusting the laser engraving speed of the laser to 3000-5000 mm / s, and laser cutting the surface to be cut.

[0068] Preferably, in the embodiment of the present invention, the laser engraving speed of the laser can be adjusted to 3000-4000 mm / s to perform laser cutting on the surface to be cut.

[0069] When laser cutting the surface to be cut, there are unavoidable defects in the cut cross-section of the cell after cutting, so corresponding measures must be taken to passivate the cut cross-section to varying degrees. The existing technology generally adopts the method of passivating the cell after the cell is split. Due to the special characteristics of laser cutting, there is a technical prejudice that laser cutting and passivation cannot be performed simultaneously. The inventors have found that after laser cutting of the cell, the silicon atoms in the cut cross-section of the cell cannot maintain their original orderly arrangement state, forming dangling bonds. This provides the basis for the simultaneous performance of laser cutting and passivation.

[0070] The inventors further discovered that when laser cutting is used on the cut surface of a silicon heterojunction solar cell, spraying a passivation solution on the laser-irradiated area can cause the silicon at the cut to react chemically with the passivation solution to achieve a passivation effect. That is, the embodiment of the present invention provides a solution spray passivation treatment for the laser-irradiated area, comprising: using a passivation solution to spray the laser-irradiated area for passivation treatment, so that the passivation solution and the silicon at the cut of the surface to be cut undergo a chemical reaction passivation, wherein the chemical reaction passivation includes the coordination of the groups in the passivation solution with the unsaturated dangling bonds of silicon. Optionally, the passivation solution is a solution of aminosulfonic acid dissolved in deionized water; the concentration of the solution of aminosulfonic acid dissolved in the deionized water is 5%-10%; and the temperature of the passivation solution is 10-20°C, preferably 10°C, 12°C, 14°C, 16°C, 18°C ​​or 20°C.

[0071] Specifically, the passivation solution provided in the embodiment of the present invention is a solution of aminosulfonic acid dissolved in deionized water. The specific principle of solution passivation is as follows: from the perspective of chemical bonds, the smallest unit that plays a passivating role is the sulfonic acid group. There is a σ bond and a π bond in the S=O double bond, which, combined with the hydroxyl group -OH, forms a special electron cloud interaction with the Si dangling bond. The passivation effect comes from the oxidation of the silicon surface at the cut by aminosulfonic acid, and this oxidation is completed by grafting the O on the sulfonic acid group in aminosulfonic acid to the dangling bond on the silicon surface. As shown in Figure 5, a schematic diagram of the coordination of the sulfonic acid group on the silicon surface at the cut provided by the embodiment of the present invention and the unsaturated dangling bond of silicon is shown, and each black dot in the black dot array in the figure represents a silicon atom.

[0072] The silicon heterojunction solar cell slices without laser grooving and passivation solution treatment, only laser grooving and passivation solution treatment, and laser cutting and passivation treatment provided by the embodiments of the present invention were tested respectively. The test parameters were set as follows: the laser used for laser grooving was a nanosecond green laser, the laser spot size was 150μm, the power was controlled at 40W, and the laser engraving speed was controlled at 1800mm / s. The laser used for laser scribing was a nanosecond red laser, the laser spot size was 50μm, the power was controlled at 20W, and the laser engraving speed was controlled at 3500mm / s. The concentration of aminosulfonic acid in deionized water was 8%, and the temperature of the solution during scribing spraying was 18°C. The test results obtained are shown in Table 1, where I SC Indicates short-circuit current, V OC represents open circuit voltage, FF represents fill factor, and Eta represents photoelectric conversion efficiency.

[0073] Test conditions ISC (A) VOC (V) FF (%) Eta (%) Without laser grooving and passivation solution treatment 6.546 0.744 8 3.348 24.514 Only laser grooving 6.560 0.745 8 3.403 24.614 Only passivation solution treatment 6.549 0.746 8 3.687 24.703 Laser grooving, cutting and passivation treatment 6.565 0.746 8 3.817 24.773

[0074] Table 1

[0075] As can be seen from Table 1, the photoelectric conversion efficiency of the silicon heterojunction solar cell slices subjected to only laser grooving and passivation solution treatment and the laser cutting and passivation treatment provided by the embodiments of the present invention is improved compared with the solar cell slices without laser grooving and passivation solution treatment; in particular, the photoelectric conversion efficiency of the silicon heterojunction solar cell slices subjected to laser cutting and passivation treatment according to the embodiments of the present invention is further improved compared with the silicon heterojunction solar cell slices subjected to only laser grooving and passivation solution treatment; and the photoelectric conversion efficiency of the silicon heterojunction solar cell slices subjected to laser cutting and passivation treatment provided by the embodiments of the present invention is improved by 0.259% compared with the solar cell slices without laser grooving and passivation solution treatment.

[0076] Test results confirm that silicon heterojunction solar cells fabricated using the laser cutting and passivation methods provided by the embodiments of the present invention exhibit improved passivation and superior photovoltaic performance. This indicates that laser grooving and positioning of silicon heterojunction solar cells, combined with treatment with a passivation solution during the laser scribing process, significantly improves their photoelectric conversion efficiency.

[0077] An embodiment of the present invention provides a method for laser cutting and passivation of silicon heterojunction solar cells, comprising: providing a silicon heterojunction solar cell; performing laser grooving and positioning on a surface to be cut of the silicon heterojunction solar cell to form at least one pair of first cutting positioning grooves and second cutting positioning grooves arranged oppositely, wherein the surface to be cut is the front surface or the back surface of the silicon heterojunction solar cell; performing laser cutting on the surface to be cut along a line connecting the first cutting positioning groove to the second cutting positioning groove, and simultaneously performing a solution spray passivation treatment on the laser irradiated area, wherein the cut portion of the surface to be cut is naturally split due to the heat of the laser irradiation and the cooling of the solution spray.

[0078] As can be seen from the above, the technical solution provided by the embodiment of the present invention first forms two relatively arranged cutting positioning grooves on the silicon heterojunction solar cell, and then performs the subsequent laser cutting step. This significantly reduces the cutting damage and thermal impact caused by cutting the silicon heterojunction solar cell during the cutting process, allowing the silicon heterojunction solar cell to self-heat and split due to thermal stress, thereby reducing the efficiency loss of the silicon heterojunction solar cell cutting. In addition, while the silicon heterojunction solar cell is being laser cut, the laser irradiated area is simultaneously passivated by spraying a solution. Thus, not only the purpose of performing laser cutting and passivation treatment simultaneously is achieved, but also the purpose of chemical cleaning and passivation treatment of the cut area is achieved simultaneously through solution spraying. On the basis of ensuring the successful passivation of the cut area and improving the photovoltaic conversion efficiency of the solar cell, the process flow is simplified and production efficiency is improved.

[0079] In the description of the present invention, it should be understood that the orientations or positional relationships indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0081] In the present invention, unless otherwise specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or communication between them; direct connections or indirect connections through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0082] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0083] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0084] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for laser cutting and passivation of silicon heterojunction solar cells, characterized in that: include: Providing a silicon heterojunction solar cell; Performing laser grooving and positioning on the surface to be cut of the silicon heterojunction solar cell to form at least one pair of first cutting positioning grooves and second cutting positioning grooves that are arranged opposite to each other, wherein the surface to be cut is the front surface or the back surface of the silicon heterojunction solar cell; The surface to be cut is laser cut along the line between the first cutting positioning groove and the second cutting positioning groove, and the laser irradiated area is passivated by solution spraying, wherein the cutting part of the surface to be cut is naturally split by the heat of laser irradiation and cooling of solution spraying.

2. The method for laser cutting and passivation of silicon heterojunction solar cells according to claim 1, characterized in that: The laser irradiated area is subjected to solution spray passivation treatment, including: The passivation solution is used to perform solution spray passivation treatment on the area irradiated by the laser, so that the passivation solution and the silicon at the cutting position of the surface to be cut undergo chemical reaction and passivation.

3. The method for laser cutting and passivation of silicon heterojunction solar cells according to claim 2, characterized in that: The chemical reaction passivation includes coordination of the groups in the passivation solution with unsaturated dangling bonds of silicon.

4. The method for laser cutting and passivation of silicon heterojunction solar cells according to claim 2, characterized in that: The passivation solution is a solution of aminosulfonic acid dissolved in deionized water; The concentration of the aminosulfonic acid dissolved in the deionized water is 5%-10%; And, the temperature of the passivation solution is 10-20°C.

5. The method for laser cutting and passivation of silicon heterojunction solar cells according to claim 1, characterized in that: Laser cutting the surface to be cut includes: The laser spot size of the laser is adjusted to a range of 30-100 μm, and the surface to be cut is laser cut.

6. The method for laser cutting and passivation of silicon heterojunction solar cells according to claim 1, characterized in that: Laser cutting the surface to be cut includes: The rated power range of the laser is adjusted to 10-30W, and the surface to be cut is laser cut.

7. The method for laser cutting and passivation of silicon heterojunction solar cells according to claim 1, characterized in that: Laser cutting the surface to be cut includes: The laser engraving speed of the laser is adjusted to 3000-5000 mm / s, and the surface to be cut is laser cut.

8. The method for laser cutting and passivation of silicon heterojunction solar cells according to claim 1, characterized in that: Laser grooving and positioning of the surface to be cut of silicon heterojunction solar cells, including: The size of the laser spot of the laser is adjusted to a range of 30-200 μm, and the laser grooving positioning is performed on the surface to be cut of the silicon heterojunction solar cell.

9. The method for laser cutting and passivation of silicon heterojunction solar cells according to claim 1, characterized in that: Laser grooving and positioning of the surface to be cut of silicon heterojunction solar cells, including: The rated power range of the laser is adjusted to 20-50W, and the laser groove positioning is performed on the surface to be cut of the silicon heterojunction solar cell.

10. The method for laser cutting and passivation of silicon heterojunction solar cells according to claim 1, characterized in that: Laser grooving and positioning of the surface to be cut of silicon heterojunction solar cells, including: The laser engraving speed of the laser is adjusted to 1500-3000 mm / s, and the surface to be cut of the silicon heterojunction solar cell is laser grooved and positioned.

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