Method of manufacturing a photovoltaic module and photovoltaic module

Abstract

This application provides a method for manufacturing a photovoltaic module and a photovoltaic module. The method includes: arranging multiple solar cells at intervals along a first direction; arranging multiple solder strips on the pads of the multiple solar cells, the solder strips being arranged along a second direction, the second direction forming an angle with the first direction; simultaneously performing laser welding on the multiple solder strips and pads using at least one first laser beam, the laser welding area being the area where the pads are located; and using at least one second laser beam to break the solder strips at at least a portion of the intervals between adjacent solar cells. This application solves the problem of poor welding quality in existing photovoltaic modules requiring welding with a large number of solder strips.

Description

Technical Field

[0001] This application relates to the field of photovoltaic energy technology, and more specifically, to a method for preparing a photovoltaic module and a photovoltaic module. Background Technology

[0002] In the current photovoltaic module manufacturing field, with the continuous advancement of cell technology, especially the increase in the number of grid lines in solar cells, the aim is to reduce series resistance losses by shortening the current transmission path, thereby improving current collection efficiency and cell conversion efficiency, while also enhancing the cell's resistance to mechanical stress and optimizing overall reliability. This trend has led to the widespread application of ultra-high grid line (UHMR) solar cells (i.e., cells with more than 20 grid lines or solder ribbons). However, the introduction of UHMR solar cells has also brought new technical challenges, especially in the string bonding process between the cell and the solder ribbon.

[0003] The information disclosed above in the background section is only intended to enhance the understanding of the background art of the art described herein. Therefore, the background art may contain certain information that does not constitute prior art known to those skilled in the art in this country. Summary of the Invention

[0004] The main objective of this application is to provide a method for manufacturing a photovoltaic module and a photovoltaic module in order to solve the problem of poor welding quality in photovoltaic modules that require a large number of solder strips in the prior art.

[0005] To achieve the above objectives, according to one aspect of this application, a method for manufacturing a photovoltaic module is provided, comprising: arranging a plurality of solar cells at intervals along a first direction; arranging a plurality of solder ribbons on pads of the plurality of solar cells, the plurality of solder ribbons being arranged along a second direction having an angle with the first direction; simultaneously performing laser welding on the plurality of solder ribbons and the pads using at least one first laser beam, the laser welding area being the area where the pads are located; and breaking the solder ribbons at at least a portion of the intervals between adjacent solar cells using at least one second laser beam.

[0006] Optionally, the step of simultaneously performing laser spot welding on multiple solder strips and solder pads using at least one of the first laser beams includes: placing a beam splitter at the output port of a laser, wherein when the laser emits the first laser beam, the beam splitter converts the first laser beam emitted by the laser into multiple sub-laser beams, and the multiple sub-laser beams simultaneously perform laser spot welding on multiple solder strips and solder pads.

[0007] Optionally, the preparation method further includes: providing a plurality of first pads on both sides of the battery cell in the first direction, the plurality of first pads being arranged along the second direction, and providing a plurality of second pads in the first direction, the second pads being located between two first pads, the size of the second pads being smaller than the size of the first pads.

[0008] Optionally, the preparation method further includes: in the step of simultaneously performing laser welding on the plurality of solder strips and the solder pads with the first laser beam, the first laser beam moves along the first direction.

[0009] Optionally, the preparation method further includes: in the step of simultaneously performing laser welding on the plurality of solder strips and the solder pads with the first laser beam, the first laser beam moves along the second direction.

[0010] Optionally, the preparation method further includes: welding the first pad and the solder strip using a first laser beam with a laser spot diameter of 0.5~4mm and a power of 50~80W; the preparation method further includes: welding the second pad and the solder strip using a first laser beam with a laser spot diameter of 0.5~4mm and a power of 20~50W.

[0011] Optionally, the preparation method further includes: using a second laser beam with a laser spot diameter of 0.1~2mm and a power of 2~6KW to break the solder strip located at the interval between adjacent solar cells.

[0012] Optionally, after the step of breaking the solder strip at at least a portion of the interval between adjacent solar cells using at least one of the second laser beams, the breaks of adjacent solder strips are staggered in the second direction.

[0013] Optionally, the preparation method further includes: placing the provided plurality of solar cells on a substrate having a plurality of grooves, the positions of the grooves corresponding to the intervals between adjacent solar cells; and collecting the solder strip debris that falls into the grooves after breaking the solder strip located at the intervals between adjacent solar cells using at least one of the second laser beams.

[0014] According to another aspect of this application, a photovoltaic module is provided, which is prepared using the photovoltaic module preparation method described above.

[0015] The technical solution of this application involves first arranging multiple solar cells at intervals along a first direction; then arranging multiple solder strips on the pads of the multiple solar cells, with the solder strips arranged along a second direction at an angle to the first direction; simultaneously performing laser welding on the multiple solder strips and pads using at least one first laser beam, with the laser welding area being the area where the pads are located; and finally, using at least one second laser beam to break the solder strips at at least a portion of the intervals between adjacent solar cells. This method differs from the prior art where the solder strips are pre-cut and then gripped to the corresponding positions on the solar cells. The method of this application only requires solder strip traction mechanisms at both ends, eliminating the need for additional solder strip cutting and gripping mechanisms. Furthermore, this application uses a first laser beam to simultaneously perform precise point-to-point welding on multiple solder strips and pads, which not only improves welding efficiency but also ensures the quality of each weld point. Furthermore, point-to-point welding avoids surface heating of the solar cells, which can reduce module reliability (surface heating causes the solder ribbon and silicon wafer to be heated simultaneously, and due to the large difference in thermal expansion coefficients between the silicon wafer and the solder ribbon, greater thermal stress is generated in the cell string after cooling), thus improving the reliability and stability of the solar cells. Using at least one second laser beam to break at least a portion of the solder ribbon between adjacent solar cells ensures the accuracy of the solder ribbon segmentation, avoids the short-circuit risk caused by solder ribbon residue, and thus solves the problem of poor welding quality in existing photovoltaic modules requiring multiple solder ribbons. Improving the welding quality of multiple solder ribbons can further enhance the current collection efficiency and cell conversion efficiency of photovoltaic modules. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0017] Figure 1 A schematic flowchart of a method for manufacturing a photovoltaic module according to an embodiment of this application is shown;

[0018] Figure 2 It shows Figure 1 A schematic diagram illustrating the structural changes of a photovoltaic module in its preparation method;

[0019] Figure 3 A schematic diagram of the first type of laser welding structure is shown;

[0020] Figure 4 A schematic diagram of the second type of laser welding is shown;

[0021] Figure 5 A schematic diagram of the structure of laser-cut welding strip is shown;

[0022] Figure 6A schematic diagram of the structure of a photovoltaic module according to an embodiment of this application is shown.

[0023] The above figures include the following reference numerals:

[0024] 01. First laser beam; 02. Second laser beam; 10. Battery cell; 20. Solder ribbon; 30. Beam splitter; 40. Laser; 50. Sub-laser beam; 61. First solder pad; 62. Second solder pad; 71. Groove; 72. Substrate; 81. Encapsulation film; 82. Cover plate. Detailed Implementation

[0025] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element present. Furthermore, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element via a third element.

[0029] As described in the background section, the welding quality of solar cells with many grid lines that need to be welded in the prior art is not ideal. In order to solve the problem of poor welding quality of photovoltaic modules that require a lot of solder strips in the prior art, the embodiments of this application provide a method for preparing a photovoltaic module and a photovoltaic module.

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0031] Figure 1 This is a flowchart of a method for manufacturing a photovoltaic module according to an embodiment of this application. Figure 1 As shown, the method includes the following steps:

[0032] Step S1, as follows Figure 2 As shown in (a), a plurality of the above-mentioned battery cells 10 are arranged at intervals along the first direction X;

[0033] Specifically, each solar cell has multiple pads arranged in an array. The number of rows or columns of pads is preferably a multiple of the number of laser beams after beam splitting. For example, if the number of laser beams after beam splitting is 100, the number of pads in the solar cell string should match the number of rows or columns and should be an integer multiple of the number of laser beams, i.e., at least 100, 200, 300, 400, etc. This maximizes the utilization of laser energy and avoids waste.

[0034] Step S2, as follows Figure 2 As shown in (a), a plurality of solder ribbons 20 are arranged on the solder pads (not shown) of a plurality of the aforementioned battery cells 10, and the plurality of the aforementioned solder ribbons 20 are arranged along a second direction Y, wherein the second direction Y has an angle with the aforementioned first direction X;

[0035] Specifically, placing the entire welding strip directly onto the solar cell requires only welding strip traction mechanisms at both ends, eliminating the need for additional welding strip cutting and clamping mechanisms, thus saving both machine space and equipment costs. Setting the welding strip's extension direction to follow the distribution of multiple solar cells allows for series connection of the cells, converging the charge carriers generated by each cell. Furthermore, the spacing between multiple welding strips can be equal, facilitating simultaneous laser welding of multiple strips.

[0036] Step S3 uses at least one first laser beam to simultaneously perform laser welding on multiple of the above-mentioned solder strips and the above-mentioned pads, wherein the area of ​​the laser welding is the area where the above-mentioned pads are located.

[0037] Specifically, the laser beam diameter can be 0.5-4mm, the solder strip width can be 0.2-2mm, and the laser beam power can be set between 20-80W to ensure that the solder strip is sufficiently heated to the melting point of tin (130-300℃). The area of ​​the solder pad is very small relative to the entire surface of the cell; it can be considered a single point. Point-to-point precise welding using the laser beam concentrates heat in the solder joint area, preventing unnecessary heat diffusion to other parts of the cell. This reduces cell deformation and damage, and also reduces the accumulation of thermal stress between the solder strip and the cell after cooling, improving the long-term reliability of the module. Using laser welding instead of traditional surface heating welding achieves precise control of the solder joint, ensuring high-quality solder joints and a reliable connection between the solder strip and the cell. Furthermore, due to the localized heating characteristics of the laser beam, the thermal stress on the cell is significantly reduced, improving the module's TC reliability test performance.

[0038] Step S4, as follows Figure 2 (b) and Figure 2 As shown in (c), at least one second laser beam is used to break the solder strip 20 at the interval between at least a portion of adjacent solar cells 10;

[0039] Specifically, the aforementioned gaps between at least some adjacent solar cells refer to the fact that not all gaps between adjacent solar cells will have their solder joints broken, for example... Figure 2 As shown in (c), in the first direction X, two solder ribbons at the interval between the first and second solar cells are broken, leaving two ribbons intact; similarly, two solder ribbons at the interval between the second and third solar cells are broken, leaving two ribbons intact. The spot diameter of the second laser beam can be 0.1-2 mm, and the power can be 2-6 kW. The purpose of laser breaking is to connect only the PN terminals of adjacent solar cells, thus achieving positive and negative terminal connection between adjacent solar cells and forming a photovoltaic module. After breaking the solder ribbons, the remaining solder ribbon residue is collected by a suction mechanism to prevent solder ribbon residue from remaining at the break point and causing a short circuit.

[0040] Specifically, this application can use a second laser beam to sequentially break the gaps between adjacent solar cells, for example, by... Figure 2 (c) Taking this as an example, following the order from left to right, a second laser beam is used to first break the solder strip at the first interval, then the solder strip at the second interval, and so on until all solder strip breaking steps are completed. This application can also use multiple second laser beams to break the gaps between adjacent solar cells; for example, this application uses two second laser beams... Figure 2(c) For example, in order from left to right, the first second laser beam can break the solder strip that needs to be broken at the first interval, and the second second laser beam can break the solder strip that needs to be broken at the second interval. The above breaking steps are performed simultaneously. Using multiple second laser beams to work at the same time can improve the breaking efficiency. This application does not make specific limitations on how to allocate the two second laser beams to the specific breaking positions, and this application can also use more second laser beams. This application does not make specific limitations on the specific setting form.

[0041] This embodiment requires only two ends of the solder ribbon traction mechanism, eliminating the need for additional solder ribbon cutting and clamping mechanisms, thus reducing the cost of photovoltaic module manufacturing. Furthermore, this application employs at least one first laser beam to simultaneously perform precise point-to-point welding of multiple solder ribbons and pads, improving welding efficiency and ensuring the quality of each weld point. Point-to-point welding also avoids surface heating of the cells, which can reduce module reliability (surface heating causes simultaneous heating of the solder ribbon and silicon wafer, and due to the large difference in thermal expansion coefficients between the silicon wafer and the solder ribbon, greater thermal stress occurs in the cell string after cooling), thereby improving the reliability and stability of the cells. Using at least one second laser beam to break at least a portion of the solder ribbon between adjacent cells ensures the accuracy of solder ribbon segmentation, avoiding short-circuit risks caused by solder ribbon residue, and thus solving the problem of poor welding quality in photovoltaic modules requiring multiple solder ribbons in the prior art. Improved welding quality of multiple solder ribbons can further enhance the current collection efficiency and cell conversion efficiency of photovoltaic modules.

[0042] In specific implementation, step S3 above uses at least one of the first laser beams to simultaneously perform laser spot welding on multiple solder strips and solder pads, which can be achieved through the following steps: Figure 3As shown, a beam splitter 30 is placed at the output port of the laser 40. When the laser 40 emits the first laser beam, the beam splitter 30 converts the first laser beam emitted by the laser 40 into multiple sub-laser beams 50. These multiple sub-laser beams 50 simultaneously perform laser spot welding on multiple solder ribbons 20 and solder pads (not shown). The first laser beam emitted by the laser 40 is converted by the beam splitter 30 into multiple sub-laser beams 50 of equal power. The spacing of these sub-laser beams 50 matches the spacing of the solder ribbons 20 on the solar cell 10, ensuring that each solder joint receives the same welding energy. The diameter of the sub-laser beams 50 can be in the range of 0.5-4 mm to fully cover the width of the solder ribbons 20, while the radius of the sub-laser beams 50 is smaller than the spacing between the solder ribbons (2-12 mm) to avoid affecting adjacent solder joints. Using this laser spot welding method, the welding temperature and time of each solder joint can be precisely controlled, achieving highly consistent welding quality, while reducing the thermal stress on the solar cell 10 caused by surface heating. Furthermore, multiple welding strips 20 can be welded simultaneously using a single first laser beam, thus improving the welding speed.

[0043] Step S3 above can also involve using multiple first laser beams, adjusting the spacing between them, and moving them along the extension direction of the solder strip to perform spot welding on the solder strip and the solder pad. Alternatively, one or more of the multiple first laser beams can be split by a beam splitter, while the remaining first laser beams are not split, and the solder strip is welded using this method. The number of first laser beams used can be adjusted according to the actual work process, and this application does not impose a specific limitation.

[0044] For back-contact cells, the positive and negative grid lines and solder ribbons are all on one side of the cell. After welding, due to the large difference in thermal expansion coefficients between the silicon wafer and the solder ribbon, significant thermal stress is generated on the silicon wafer upon cooling. During TC reliability testing, the solder ribbons at the edge solder joints of the cell are prone to detachment, affecting module reliability. In some optional embodiments, the above-mentioned preparation method further includes: Figure 4 As shown, multiple first pads 61 are provided on both sides of the aforementioned battery cell 10 in the first direction X, and the multiple first pads 61 are arranged along the second direction Y. Multiple second pads 62 are provided in the first direction X, located between two of the first pads 61. The size of the second pads 62 is smaller than the size of the first pads 61. By setting the first pads 61 at both ends of the battery cell 10 to be larger, more solder ribbons 20 can be connected to the first pads 61 during soldering, improving the ability to withstand tensile forces. Even if the solder ribbons 20 experience significant shrinkage forces during cooling, the risk of solder ribbon detachment can be reduced.

[0045] In step S3 above, during the step of simultaneously performing laser welding on multiple solder strips and solder pads with the first laser beam, as follows: Figure 3 As shown, the first laser beam moves along the first direction X. The continuous movement of the laser beam along the first direction X allows the laser welding process to proceed like an assembly line, with the formation and cooling of the weld joint almost instantaneous, reducing heat conduction to surrounding materials and thus lowering the thermal stress of the solar cell. Furthermore, by controlling the movement speed of the laser beam, the heating time of each weld joint can be adjusted, ensuring that the solder strip 20 and the solder pad cool rapidly when they reach the optimal welding state, forming a strong electrical connection. This not only improves welding efficiency but also ensures the continuity of the welding process and the consistency of the weld joints, reducing weld defects such as incomplete welds or over-welds caused by excessively long or short welding dwell times. By precisely controlling the movement speed and position of the laser beam, the heated area and duration of the solar cell can be effectively reduced, lowering thermal stress and enhancing the reliability and long-term stability of the module.

[0046] The fundamental cause of thermal stress in back-contact batteries is that both the solder strip and the silicon wafer expand simultaneously during the welding process. However, the coefficient of thermal expansion of the metal solder strip is much greater than that of the silicon wafer. Therefore, the shrinkage of the solder strip after welding is much greater than that of the silicon wafer, generating significant thermal stress and making the battery cell prone to warping. Furthermore, the contact point between the solder strip and the solder joint is subjected to a large force, making it prone to detachment during thermal stress (TC). Therefore, greater efforts are needed to alleviate the thermal stress. In some optional embodiments, in step S3, where the first laser beam simultaneously performs laser welding on multiple solder strips and solder pads, such as... Figure 4 As shown, the first laser beam 01 moves along the second direction Y. The direction of laser welding is changed from the scanning direction along the solder strip 20 to a direction perpendicular to the extension direction of the solder strip 20, and spot welding is performed on the solder strip 20 and the pad. For example, the first row of solder strips 20 is welded first. At this time, the solder strips 20 are not welded to the second row of pads, and the solder strips can shrink normally to release thermal stress. Then, after the first row is welded, the second row is welded, and so on, until all solder strips and solder points are welded, thus completing the fabrication of the low thermal stress battery string.

[0047] By adjusting the power in real time, different laser powers can be applied to different solder joints. In some optional embodiments, the above preparation method further includes: using the first laser beam with a laser spot diameter of 0.5~4mm and a power of 50~80W to weld the first solder pad and the solder strip. This allows for high-power laser welding of large solder joints, ensuring welding quality and avoiding cold solder joints. The first laser beam with a laser spot diameter of 0.5~4mm and a power of 20~50W is then used to weld the second solder pad and the solder strip. Low-power laser welding is used for small solder joints to avoid over-welding.

[0048] In the above-mentioned optional embodiments, excessive power may lead to over-melting of the solder joint, causing solder overflow, solder strip deformation, or cell damage; while insufficient power may lead to insufficient welding, resulting in poor solder joints or increased contact resistance. Using higher power (50~80W) when welding the larger first pad ensures a larger molten area between the solder strip and the first pad, resulting in a stronger connection and enhancing the stability of the electrical connection. When welding the smaller second pad, the required welding strength is lower, so lower power (20~50W) is used. This achieves stable solder strip connection while avoiding overheating of the cell, reducing thermal stress. Especially for edge solder joints, this control effectively prevents solder strip detachment during TC testing, improving the overall reliability and lifespan of the module. Furthermore, the optimization of the laser spot diameter ensures that the laser energy is evenly distributed across the width of the solder strip, avoiding localized overheating caused by excessive energy concentration, further improving the controllability of the welding process and the quality of the solder joints. This embodiment achieves precise welding of pads and solder strips and minimizes thermal stress by classifying and controlling the laser beam spot diameter and power, thereby significantly improving the welding quality and reliability of photovoltaic modules.

[0049] In the case of back-contact solar cells, in order to ensure that multiple solar cells can be connected together to form a photovoltaic module, in some optional implementation methods, such as... Figure 2 As shown in (c), after step S3 above, where at least one second laser beam is used to break the solder ribbon 20 at the intervals between at least a portion of adjacent solar cells 10, the breaks in adjacent solder ribbons 20 are staggered in the second direction Y. This allows the positive and negative electrodes (PN electrodes) between adjacent solar cells to be connected through the solder ribbon 20 and avoids short circuits, enabling multiple solar cells to be connected in series to form a photovoltaic module.

[0050] In some optional embodiments, the above preparation method further includes: using a second laser beam with a laser spot diameter of 0.1~2mm and a power of 2~6KW to break the solder strip located at the interval between adjacent solar cells. After completing the laser welding of the solder strip and the pad, at least one second laser beam can be used to precisely break the solder strip to form independent cell strings and avoid electrical short circuits. The spot diameter of the second laser beam can be a small diameter of 0.1~2mm, which can ensure the accuracy and efficiency of the breaking. At the same time, this diameter range also helps to prevent unnecessary damage to the solar cells and pads during the breaking process. The power range can be 2~6KW, which is based on the requirement of breaking the solder strip rather than welding. For solder strip (usually tin-coated copper strip or aluminum strip), its melting point (copper: about 1083℃, aluminum: about 660℃) is much higher than the melting point of solder (tin: about 232℃), so a higher power is required to melt the solder strip. A power of 2~6KW can ensure that the solder strip is heated to the melting temperature (about 1083℃) in a short time (a few milliseconds to tens of milliseconds) to complete the breaking task, while avoiding thermal damage to the material caused by prolonged heating.

[0051] During the laser cutting process of the solder ribbon, molten metal fragments may splash or adhere to the surface of the solar cell or adjacent solder ribbons. If not removed promptly, these fragments may form electrical paths during component assembly or use, leading to short circuits or other malfunctions. In some alternative implementations, such as Figure 5 As shown, the above-described preparation method further includes: placing a plurality of the provided solar cells 10 on a substrate 72 having a plurality of grooves 71, the positions of which correspond to the intervals between adjacent solar cells 10; and collecting the solder ribbon 20 debris that falls into the grooves 71 after the solder ribbon 20 located at the intervals between adjacent solar cells 10 is broken using at least one of the second laser beams 02. In the process of preparing the solar cell string, the solar cells 10 are neatly arranged on a specially designed substrate 72, which is designed with a plurality of grooves 71. The positions of these grooves 71 are designed to match the cutting positions of the solder ribbon 20 between adjacent solar cells 10. When the second laser beam 02 cuts the solder ribbon 20, the molten solder ribbon 20 fragments naturally fall into the corresponding grooves 71. Subsequently, these scattered solder ribbon 20 fragments are efficiently collected by an integrated vacuum suction device or collection mechanism or other blowing device to prevent them from becoming a hidden danger affecting the performance of the solar cell string and the module. This method not only keeps the work area clean, but also allows for the recycling of the welding strip material, reducing production costs.

[0052] The above method can immediately isolate solder ribbon fragments from solar cells and collect the solder ribbon fragments, ensuring that they do not contaminate the working environment or affect the functionality of the solar cells. This method avoids the efficiency loss and potential incomplete cleaning problems caused by manual intervention.

[0053] In this application, the solder strip can be a copper strip coated with an alloy tin-lead solder (SnPb) to improve the fluidity and wettability of the solder, ensuring a good electrical connection. The width of the solder strip can be customized according to the specifications of the solar cell and the welding requirements, for example, the width range can be 0.2~2mm. The SnPb coating on the outer layer of the solder strip melts rapidly during the welding process to form solder joints, realizing the metallized interconnection between the solar cell and the solder strip. The solder pad is a metal layer on the solar cell used to connect with the solder strip, generally using aluminum alloy or silver as the base, with a SnPb alloy welding layer formed on the surface through chemical deposition or electroplating. The substrate material can be a heat-resistant material such as polyimide (PI). The substrate is designed with multiple grooves, the position and size of which match the gap between adjacent solar cells and the break position of the solder strip, to ensure that the residue after the solder strip is broken can fall directly into the groove, facilitating subsequent cleaning and collection. The substrate can also have anti-laser reflection properties to prevent unnecessary reflection of the laser during the welding process, which would affect the welding quality and equipment safety.

[0054] According to another embodiment of this application, a photovoltaic module is prepared using the above-described photovoltaic module preparation method. Figure 6 As shown, the photovoltaic module includes: a cell string, formed by connecting multiple of the aforementioned solar cells 10; an encapsulating film 81 for covering the surface of the cell string; and a cover plate 82 for covering the surface of the encapsulating film 81 facing away from the cell string. Adjacent solar cells 10 can be electrically connected to each other via the aforementioned solder ribbon 20.

[0055] The aforementioned encapsulating film can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene elastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first or second encapsulating layer can also be an EP film, EPE film, or PVP film. Specifically, EP film refers to a co-extruded film composed of stacked EVA and POE films; EPE film refers to a co-extruded film formed by sequentially stacking EVA, POE, and EVA films; and PVP film refers to a co-extruded film formed by stacking POE, EVA, and POE films. The co-extruded film can be manufactured by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0056] The aforementioned cover plate can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate facing the encapsulating film can be an uneven surface or a textured surface containing multiple raised structures, which can increase the utilization rate of incident light.

[0057] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a photovoltaic module, characterized in that, include: Multiple solar cells are arranged at intervals along a first direction; Multiple solder ribbons are arranged on the pads of multiple solar cells, and the multiple solder ribbons are arranged along a second direction, which forms an angle with the first direction; At least one first laser beam is used to simultaneously perform laser welding on multiple solder strips and solder pads, wherein the area of ​​laser welding is the area where the solder pads are located. The solder strip is broken at least a portion of the interval between adjacent solar cells using at least one second laser beam.

2. The preparation method according to claim 1, characterized in that, The method of simultaneously performing laser spot welding on multiple solder strips and solder pads using at least one of the first laser beams includes: A beam splitter is placed at the laser's output port. When the laser emits the first laser beam, the beam splitter converts the first laser beam into multiple sub-laser beams. The multiple sub-laser beams simultaneously perform laser spot welding on multiple solder strips and solder pads.

3. The preparation method according to claim 1, characterized in that, The preparation method further includes: setting a plurality of first pads on both sides of the battery cell in the first direction, the plurality of first pads being arranged along the second direction, and setting a plurality of second pads in the first direction, the second pads being located between two first pads, the size of the second pads being smaller than the size of the first pads.

4. The preparation method according to claim 3, characterized in that, The preparation method further includes: in the step of simultaneously performing laser welding on multiple solder strips and solder pads with the first laser beam, the first laser beam moves along the first direction.

5. The preparation method according to claim 3, characterized in that, The preparation method further includes: in the step of simultaneously performing laser welding on multiple solder strips and solder pads with the first laser beam, the first laser beam moves along the second direction.

6. The preparation method according to claim 3, characterized in that, The preparation method further includes: The first laser beam, with a laser spot diameter of 0.5~4mm and a power of 50~80W, is used to weld the first pad and the solder strip. The second pad and the solder strip are welded using a first laser beam with a laser spot diameter of 0.5~4mm and a power of 20~50W.

7. The preparation method according to claim 1, characterized in that, After the step of breaking the solder strip at least a portion of the interval between adjacent solar cells using at least one of the second laser beams, the breaks of adjacent solder strips are staggered in the second direction.

8. The preparation method according to claim 1, characterized in that, The preparation method further includes: using a second laser beam with a laser spot diameter of 0.1~2mm and a power of 2~6KW to break the welding strip located at the interval between adjacent solar cells.

9. The preparation method according to claim 1, characterized in that, The preparation method further includes: The provided battery cells are placed on a substrate having multiple grooves, the positions of which correspond to the spacing between adjacent battery cells; After the solder strip located at the interval between adjacent solar cells is broken using at least one of the second laser beams, the solder strip debris that has fallen into the groove is collected.

10. A photovoltaic module, characterized in that, The photovoltaic module is prepared using the method described in any one of claims 1 to 9.

Images