Black photovoltaic welding strip and preparation method and preparation device thereof

Abstract

The invention provides a black photovoltaic welding strip and a preparation method and a preparation device thereof. The preparation device is provided with an unwinding assembly, a blackening assembly and a winding assembly in the conveying direction of a photovoltaic welding strip to be processed. The blackening assembly comprises a blackening liquid supply device and a blackening wheel, the blackening wheel is provided with a lifting driving mechanism, the lifting driving mechanism is used for driving the blackening wheel to periodically move up and down, and intermittent rotating contact between the blackening wheel and the to-be-blackened face of the to-be-treated photovoltaic welding strip is achieved; the blackening wheel sequentially comprises a wheel shaft, a porous blackening liquid guide cavity and a sponge layer from inside to outside in the radial direction, and blackening liquid permeates into the sponge layer through the porous blackening liquid guide cavity so as to achieve single-face intermittent blackening on the to-be-treated photovoltaic welding strip passing through the blackening wheel. According to the preparation device, the blackening wheel is in intermittent contact with the photovoltaic welding strip, so that single-side intermittent blackening is realized, and a blackening coating with strong adhesion and high flexibility can be formed; the preparation device can be directly integrated to a stitch welding process, does not need independent drying, and is simple in structure, efficient and energy-saving.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic ribbon technology, specifically relating to a black photovoltaic ribbon and its preparation method and apparatus. Background Technology

[0002] Photovoltaic solder ribbon is an important material in the welding process of photovoltaic modules. According to its use, it is mainly divided into busbar solder ribbon and interconnection solder ribbon. Among them, interconnection solder ribbon is a tin-coated solder ribbon used to connect photovoltaic cells and collect and transmit the current of photovoltaic cells. It is also called interconnection bar or interconnection strip. Busbar solder ribbon is a tin-coated solder ribbon used to connect photovoltaic cell strings and junction boxes and transmit the current of photovoltaic cell strings. It is also called busbar.

[0003] With the continuous development of photovoltaic module technology, in order to further improve the power of modules, all-black modules composed of black solar cells have begun to emerge. To match all-black modules, black photovoltaic solder ribbons have also been developed. Black photovoltaic solder ribbons are made by uniformly coating the non-soldering side of the photovoltaic solder ribbon with a black coating, while the other sides retain the original solder ribbon shape. This black coating is usually a black paint with added curing agent. Through solvent evaporation and curing process (thermal curing / UV curing), the adhesion of the black coating is improved, ultimately achieving single-sided black coating of the photovoltaic solder ribbon. The black-coated side faces outward and together with the black solar cells to form an all-black module, while the non-black-coated side is used for soldering to the grid lines on the solar cells.

[0004] However, existing black photovoltaic welding ribbons and their preparation methods have the following significant drawbacks: 1) High risk of welding surface contamination: Since the black coating in existing technologies is usually an insulating organic coating, if it is accidentally applied to the welding surface due to improper control during the coating process, it will seriously affect the welding performance of the photovoltaic welding ribbon and make production difficult. 2) Poor flexibility of the black coating, prone to cracking: The cured black coating and the substrate of the metal welding ribbon have significant differences in mechanical properties. When the welding ribbon is bent, laid, or when the module undergoes thermal expansion and contraction during operation, the coating is prone to micro-cracks or even delamination due to stress concentration. This not only affects the appearance of the module but may also expose the underlying metal, destroying the overall blackening effect. 3) Complex process and high cost: Traditional coating-curing processes usually require a long curing time or additional UV curing equipment, resulting in high energy consumption and long production lines. In addition, to ensure coverage, the black coating needs to reach a high thickness, which not only increases costs but also exacerbates the brittleness and cracking risk of the black coating.

[0005] Therefore, there is an urgent need to develop a high-efficiency, continuous, and precise single-sided blackening preparation device to achieve the preparation of black photovoltaic ribbons with strong adhesion, good flexibility, no impact on welding performance, and lower cost. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a black photovoltaic welding strip, its preparation method, and preparation apparatus. The present invention utilizes a blackening wheel controlled by a lifting drive mechanism. Through its periodic up-and-down movement, it achieves intermittent rotational contact with the photovoltaic welding strip to be processed. This not only achieves a single-sided intermittent distribution of the blackening coating but also ensures the precision of single-sided blackening, preventing contamination of the welding surface by the blackening liquid. Simultaneously, through the synergistic effect of the porous blackening liquid guide cavity and the sponge layer, the blackening liquid uniformly penetrates to the welding surface of the photovoltaic welding strip, forming a tightly bonded blackening coating. This blackening coating exhibits good flexibility and is not prone to cracking, significantly improving product reliability and appearance consistency. Furthermore, this preparation apparatus can be seamlessly integrated into the busbar pulling and cutting processes within a lap welding machine. Utilizing the lap welding process environment, the conversion efficiency of the blackening coating is high, eliminating the need for an additional drying process, resulting in a simpler device structure and outstanding overall benefits.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an apparatus for preparing black photovoltaic ribbon, wherein the apparatus is provided with an unwinding component, a blackening component and a winding component along the conveying direction of the photovoltaic ribbon to be processed.

[0009] The blackening component includes a blackening liquid supply device and a blackening wheel. The blackening wheel is equipped with a lifting drive mechanism, which is used to drive the blackening wheel to move up and down periodically, so as to achieve intermittent rotational contact between the blackening wheel and the surface of the photovoltaic welding strip to be blackened.

[0010] The blackening wheel includes, from the inside to the outside, a wheel axle, a porous blackening liquid guide cavity, and a sponge layer in the radial direction. The blackening liquid permeates into the sponge layer through the porous blackening liquid guide cavity to achieve single-sided intermittent blackening of the photovoltaic welding strip to be processed after passing through the blackening wheel.

[0011] This invention utilizes a blackening wheel controlled by a lifting drive mechanism. Its periodic up-and-down movement achieves intermittent rotational contact with the photovoltaic welding strip to be processed. This not only achieves a single-sided, intermittent distribution of the blackening coating but also ensures the precision of single-sided blackening, preventing contamination of the welding surface by the blackening liquid. Simultaneously, the synergistic effect of the porous blackening liquid guide cavity and the sponge layer allows the blackening liquid to uniformly penetrate the welding surface of the photovoltaic welding strip, forming a tightly bonded blackening coating. This coating exhibits good flexibility and is not prone to cracking, significantly improving product reliability and appearance consistency. Furthermore, this preparation device can be seamlessly integrated into the busbar pulling and cutting processes within a lamina welding machine. Utilizing the lamina welding process environment, the conversion efficiency of the blackening coating is high, eliminating the need for an additional drying process, resulting in a simpler device structure and outstanding overall benefits.

[0012] Preferably, the blackening component further includes a fixed platform, on which the lifting drive mechanism is disposed.

[0013] Preferably, the lifting drive mechanism includes a cylinder cavity and a lifting shaft; one end of the lifting shaft extending into the cylinder cavity is provided with a limit ring to limit the axial movement stroke of the lifting shaft; the other end of the lifting shaft is connected to the wheel axle axis through a rotary sealing joint to drive the blackened wheel to perform periodic lifting movements.

[0014] Preferably, the bottom of the cylinder cavity is provided with an air inlet and outlet for introducing or discharging gas, thereby driving the lifting shaft to perform periodic lifting and lowering movements, so as to achieve intermittent rotational contact between the sponge layer and the photovoltaic welding strip.

[0015] Preferably, the axle, the porous blackening liquid guide cavity, and the sponge layer move up and down synchronously under the drive of the lifting shaft, and the axle rotates freely relative to the lifting shaft; the axle rotates synchronously with the porous blackening liquid guide cavity.

[0016] Preferably, the blackening liquid supply device is a blackening liquid storage tank.

[0017] Preferably, the porous blackening liquid guiding cavity is provided with a liquid inlet, and the liquid inlet is connected to the liquid outlet of the blackening liquid storage tank through a pipeline; a solenoid valve is provided on the pipeline.

[0018] Preferably, the porous blackening liquid guiding cavity is a porous hollow annular cavity, the chamber of which is used to store the blackening liquid, and the blackening liquid is transported to the sponge layer through the porous structure of the hollow annular cavity.

[0019] Preferably, the deformation of the sponge layer is 1-5mm, for example, it can be 1mm, 2mm, 3mm, 4mm or 5mm, etc.

[0020] Preferably, the radial thickness of the sponge layer is 2-20 mm, for example, it can be 2 mm, 5 mm, 8 mm, 10 mm or 20 mm.

[0021] Preferably, the axial width of the sponge layer is greater than or equal to the width of the photovoltaic ribbon to be processed.

[0022] Preferably, the radial thickness of the porous blackening liquid guiding cavity is 10-200 mm, for example, it can be 10 mm, 20 mm, 50 mm, 100 mm or 200 mm. It should be noted that the radial thickness refers to the thickness of the porous blackening liquid guiding cavity from the center to the edge in the radial direction.

[0023] Preferably, the axial width of the porous blackening liquid guiding cavity is equal to the axial width of the sponge layer.

[0024] Preferably, the porosity of the porous blackening liquid guiding cavity is 10-80%, for example, it can be 10%, 20%, 50%, 70% or 80%, etc.

[0025] Preferably, the average pore diameter of the porous blackening liquid guiding cavity is 0.2-2 mm, for example, it can be 0.2 mm, 0.5 mm, 0.8 mm, 1 mm or 2 mm.

[0026] Preferably, a guide component is further provided between the unwinding component and the blackening component for conveying and guiding the photovoltaic welding strip to be processed output by the unwinding component and for attitude calibration, so that the photovoltaic welding strip to be processed maintains a horizontal conveying attitude, thereby connecting to the processing station of the blackening component.

[0027] In a second aspect, the present invention provides a method for preparing black photovoltaic ribbon, wherein the preparation method is carried out in the preparation apparatus described in the first aspect, and includes the following steps:

[0028] The photovoltaic welding strip to be processed is unwound and transported to the blackening module. By controlling the periodic up-and-down movement of the blackening wheel in the blackening module, the sponge layer in the blackening wheel, which is impregnated with blackening liquid, comes into intermittent rotational contact with the photovoltaic welding strip to be processed during the movement, forming a blackening coating with a single-sided intermittent distribution.

[0029] The black photovoltaic ribbon is obtained by rewinding using a winding assembly.

[0030] Preferably, the movement speed of the photovoltaic ribbon to be processed is 0.5-5 m / min, for example, it can be 0.5 m / min, 1 m / min, 2 m / min, 3 m / min, 4 m / min or 5 m / min, etc.

[0031] Preferably, the rotation speed of the blackening wheel is 0.1-100 rpm, for example, it can be 0.1 rpm, 1 rpm, 20 rpm, 50 rpm or 100 rpm.

[0032] Preferably, the temperature of the blackening liquid in the sponge layer impregnated with the blackening liquid is 20-50°C, for example, it can be 20°C, 30°C, 40°C or 50°C.

[0033] Preferably, the periodic up-and-down movement period is 0.5-20s, for example, it can be 0.5s, 2s, 5s, 10s or 20s.

[0034] Thirdly, the present invention provides a black photovoltaic solder ribbon, which is prepared by the preparation method described in the second aspect.

[0035] The black photovoltaic ribbon includes a photovoltaic ribbon substrate and a black coating that is intermittently distributed on one side surface of the photovoltaic ribbon substrate.

[0036] Preferably, the photovoltaic ribbon substrate is a bus ribbon or an interconnect ribbon.

[0037] Preferably, the black coating is a PbS coating or a SnS coating.

[0038] Preferably, the thickness of the black coating is 0.15-0.55 μm, for example, it can be 0.15 μm, 0.25 μm, 0.35 μm, 0.45 μm or 0.55 μm.

[0039] Preferably, in the black coating, the length of a single coating area is 5-200mm, for example, it can be 5mm, 20mm, 50mm, 100mm or 200mm.

[0040] Preferably, in the black coating, the spacing between adjacent coating areas is 5-200mm, for example, it can be 5mm, 20mm, 50mm, 100mm or 200mm.

[0041] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] This invention utilizes a blackening wheel controlled by a lifting drive mechanism. Its periodic up-and-down movement achieves intermittent rotational contact with the photovoltaic welding strip to be processed. This not only achieves a single-sided, intermittent distribution of the blackening coating but also ensures the precision of single-sided blackening, preventing contamination of the welding surface by the blackening liquid. Simultaneously, the synergistic effect of the porous blackening liquid guide cavity and the sponge layer allows the blackening liquid to uniformly penetrate the welding surface of the photovoltaic welding strip, forming a tightly bonded blackening coating. This coating exhibits good flexibility and is not prone to cracking, significantly improving product reliability and appearance consistency. Furthermore, this preparation device can be seamlessly integrated into the busbar pulling and cutting processes within a lamina welding machine. Utilizing the lamina welding process environment, the conversion efficiency of the blackening coating is high, eliminating the need for an additional drying process, resulting in a simpler device structure and outstanding overall benefits. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of a preparation apparatus provided in a specific embodiment of the present invention.

[0045] Figure 2This is an exploded view of a blackening wheel moving periodically up and down in a specific embodiment of the present invention.

[0046] Figure 3 This is a schematic diagram of the structure of a black photovoltaic welding strip provided in a specific embodiment of the present invention.

[0047] Among them, 1-unwinding assembly; 2-blackening assembly; 21-blackening wheel; 22-blackening liquid storage tank; 23-lifting drive mechanism; 231-cylinder cavity; 232-lifting shaft; 233-limiting ring; 234-air inlet and outlet; 24-fixed platform; 3-pipeline; 4-solenoid valve; 5-guide assembly; 6-photovoltaic welding strip to be processed; 7-black photovoltaic welding strip; 71-photovoltaic welding strip substrate; 72-black coating. Detailed Implementation

[0048] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0049] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0050] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0051] In one embodiment, the present invention provides an apparatus for preparing black photovoltaic ribbon 7, such as... Figure 1As shown, the preparation device is provided with an unwinding assembly 1, a blackening assembly 2 and a winding assembly along the conveying direction of the photovoltaic welding strip to be processed.

[0052] The blackening component 2 includes a blackening liquid supply device and a blackening wheel 21. The blackening wheel 21 is equipped with a lifting drive mechanism 23, which is used to drive the blackening wheel 21 to move up and down periodically, so as to realize the blackening wheel 21 and the blackening surface of the photovoltaic welding strip 6 to be processed in intermittent rotational contact.

[0053] The blackening wheel 21 includes, from the inside to the outside in the radial direction, a wheel axle, a porous blackening liquid guide cavity, and a sponge layer. The blackening liquid permeates into the sponge layer through the porous blackening liquid guide cavity to achieve single-sided intermittent blackening of the photovoltaic welding strip to be processed by the blackening wheel 21.

[0054] This invention utilizes a blackening wheel 21 controlled by a lifting drive mechanism 23. The wheel's periodic up-and-down movement enables intermittent rotational contact with the photovoltaic welding strip to be processed. This not only achieves a single-sided, intermittent distribution of the blackening coating but also ensures the precision of single-sided blackening, preventing contamination of the welding surface by the blackening liquid. Simultaneously, the synergistic effect of the porous blackening liquid guide cavity and the sponge layer allows the blackening liquid to uniformly penetrate the welding surface of the photovoltaic welding strip, forming a tightly bonded blackening coating. This coating exhibits good flexibility and is not prone to cracking, significantly improving product reliability and appearance consistency. Furthermore, this preparation device can be seamlessly integrated into the busbar pulling and cutting processes within a lamina welding machine. Utilizing the lamina welding process environment, the blackening coating has high conversion efficiency, eliminating the need for an additional drying process. This results in a simpler device structure and outstanding overall benefits.

[0055] The purpose of this invention to achieve a single-sided discontinuous distribution of the blackening coating is to precisely control the coexistence and distribution of the welding area (non-blackened) and the appearance area (blackened) on a certain side of the photovoltaic ribbon.

[0056] Furthermore, the unwinding assembly 1 is surrounded by a busbar roll for providing the photovoltaic welding strip 6 to be processed.

[0057] Furthermore, the unwinding assembly 1 is an unwinding shaft.

[0058] Furthermore, the winding assembly is a winding shaft.

[0059] For example, the porous blackening liquid guide cavity can be made of materials such as polytetrafluoroethylene, ceramic, or stainless steel.

[0060] Furthermore, the blackening component 2 also includes a fixed platform 24, on which the lifting drive mechanism 23 is provided.

[0061] Further, see Figure 2The lifting drive mechanism 23 includes a cylinder cavity 231 and a lifting shaft 232; a limit ring 233 is provided at one end of the lifting shaft 232 that extends into the cylinder cavity 231 to limit the axial movement stroke of the lifting shaft 232; the other end of the lifting shaft 232 is connected to the wheel axle axis through a rotary sealing joint to drive the blackened wheel 21 to perform periodic lifting and lowering movements.

[0062] The present invention uses a lifting drive mechanism 23 with the above structure to drive the blackening wheel 21 to move up and down periodically, which can realize the adjustable blackening function of the photovoltaic welding strip contact surface without affecting the rotation of the blackening cavity.

[0063] Furthermore, the bottom of the cylinder cavity 231 is provided with an air inlet / outlet 234 for introducing or discharging gas, thereby driving the lifting shaft 232 to perform periodic lifting and lowering movements, achieving intermittent rotational contact between the sponge layer and the photovoltaic welding ribbon. For example, compressed gas can be introduced or discharged.

[0064] Furthermore, the axle, the porous blackening liquid guide cavity, and the sponge layer move up and down synchronously under the drive of the lifting shaft 232, and the axle rotates freely relative to the lifting shaft 232; the axle rotates synchronously with the porous blackening liquid guide cavity.

[0065] In this invention, the lifting motion ensures the intermittent distribution of the black coating, while the rotational motion ensures the continuous renewal and uniform application of liquid to the contact area between the sponge layer and the photovoltaic welding ribbon, avoiding localized excessive wear and uneven coating. Thus, while achieving precise area blackening, the uniformity of the black coating and the stability of the device operation are guaranteed.

[0066] Furthermore, the blackening liquid supply device is a blackening liquid storage tank 22.

[0067] Furthermore, the porous blackening liquid guiding cavity is provided with a liquid inlet, and the liquid inlet is connected to the liquid outlet of the blackening liquid storage tank 22 through a pipeline 3; a solenoid valve 4 is provided on the pipeline 3.

[0068] The purpose of installing a solenoid valve 4 on the pipeline 3 in this invention is to control the liquid replenishment rate, thereby regulating the thickness of the black coating.

[0069] Furthermore, the porous blackening liquid guiding cavity is a porous hollow annular cavity, the chamber of which is used to store the blackening liquid, and the blackening liquid is transported to the sponge layer through the porous structure of the hollow annular cavity.

[0070] Furthermore, the deformation of the sponge layer is 1-5mm, for example, it can be 1mm, 2mm, 3mm, 4mm or 5mm, etc.

[0071] In this invention, the deformation of the sponge layer is 1-5mm, which helps the sponge layer to form a tight and uniform contact with the surface of the photovoltaic ribbon to be treated, adapting to the slight posture fluctuations during the ribbon transportation process to avoid missed coating; at the same time, this deformation can maintain the stable wetting state of the blackening liquid inside the sponge layer, preventing the blackening liquid from dripping due to excessive extrusion, ensuring uniform coating thickness, and not causing extrusion deformation to the photovoltaic ribbon substrate.

[0072] Furthermore, the radial thickness of the sponge layer is 2-20mm, for example, it can be 2mm, 5mm, 8mm, 10mm or 20mm, etc.

[0073] In this invention, the radial thickness of the sponge layer is 2-20mm, which can ensure a stable bond between the sponge layer and the surface of the photovoltaic welding ribbon to be treated, and prevent incomplete coating. At the same time, it can store a sufficient amount of blackening liquid to achieve continuous liquid supply. Combined with deformation, it can maintain the uniformity of the thickness of the blackening coating and ensure that the sponge layer has good elasticity, thus extending its service life.

[0074] Furthermore, the axial width of the sponge layer is greater than or equal to the width of the photovoltaic ribbon to be processed.

[0075] Furthermore, the radial thickness of the porous blackening liquid guiding cavity is 10-200 mm, for example, it can be 10 mm, 20 mm, 50 mm, 100 mm, or 200 mm. It should be noted that the radial thickness refers to the thickness of the porous blackening liquid guiding cavity from the center to the edge in the radial direction.

[0076] Furthermore, the axial width of the porous blackening liquid guiding cavity is equal to the axial width of the sponge layer.

[0077] Furthermore, the porosity of the porous blackening liquid guiding cavity is 10-80%, for example, it can be 10%, 20%, 50%, 70% or 80%, etc.

[0078] Furthermore, the average pore diameter of the porous blackening liquid guiding cavity is 0.2-2 mm, for example, it can be 0.2 mm, 0.5 mm, 0.8 mm, 1 mm or 2 mm, etc.

[0079] In this invention, the appropriate porosity and average pore size of the porous blackening liquid guiding cavity can provide sufficient blackening liquid flow channels to ensure a stable supply of blackening liquid, and can also accurately control the seepage rate to avoid a sudden increase in liquid volume leading to liquid accumulation in the sponge layer, thus ensuring that the sponge layer forms a uniform wetting state, providing a foundation for obtaining a continuous blackening coating with consistent thickness and no missed coating on the surface of the photovoltaic ribbon.

[0080] Furthermore, a guide component 5 is provided between the unwinding component 1 and the blackening component 2 for guiding and calibrating the photovoltaic welding strip to be processed output by the unwinding component 1, so that the photovoltaic welding strip to be processed maintains a horizontal conveying posture, thereby connecting to the processing station of the blackening component 2.

[0081] Furthermore, the guide component 5 is a guide wheel.

[0082] In another embodiment, the present invention provides a method for preparing black photovoltaic ribbon, the method being carried out in the preparation apparatus described above, and comprising the following steps:

[0083] The photovoltaic welding strip to be processed is unwound and transported to the blackening module. By controlling the periodic up-and-down movement of the blackening wheel in the blackening module, the sponge layer in the blackening wheel, which is impregnated with blackening liquid, comes into intermittent rotational contact with the photovoltaic welding strip to be processed during the movement, forming a blackening coating with a single-sided intermittent distribution.

[0084] The black photovoltaic ribbon is obtained by rewinding using a winding assembly.

[0085] The preparation process provided by this invention is simple and convenient, operates stably with low losses, requires simple equipment maintenance, and has a high yield of finished products.

[0086] Furthermore, the movement speed of the photovoltaic ribbon to be processed is 0.5-5 m / min, for example, it can be 0.5 m / min, 1 m / min, 2 m / min, 3 m / min, 4 m / min or 5 m / min, etc.

[0087] In this invention, a suitable movement speed can ensure that the blackening liquid contacts the surface of the photovoltaic solder ribbon to form a uniform black coating.

[0088] Furthermore, the rotation speed of the blackening wheel is 0.1-100 rpm, for example, it can be 0.1 rpm, 1 rpm, 20 rpm, 50 rpm or 100 rpm.

[0089] In this invention, the appropriate rotation speed of the blackening wheel, combined with the movement speed of the photovoltaic welding strip to be treated, can ensure a stable relative movement between the sponge layer and the surface of the photovoltaic welding strip. This ensures that the blackening liquid can be uniformly and fully transferred to the surface of the photovoltaic welding strip to form a black coating, while avoiding defects such as uneven thickness caused by speed mismatch. This is beneficial for obtaining a discontinuous black coating with clear outline and consistent performance.

[0090] Furthermore, the viscosity of the blackening liquid is 0.5-5 mPa·s, for example, it can be 0.5 mPa·s, 1 mPa·s, 2 mPa·s, 3 mPa·s or 5 mPa·s, etc.

[0091] Furthermore, the concentration of the blackening solution is 5-30 wt%, for example, it can be 5 wt%, 10 wt%, 15 wt%, 20 wt%, or 30 wt%.

[0092] Furthermore, in the sponge layer impregnated with blackening liquid, the temperature of the blackening liquid is 20-50℃, for example, it can be 20℃, 30℃, 40℃ or 50℃, etc.

[0093] In this invention, the temperature of the blackening solution is controlled at 20-50°C in a sponge layer impregnated with the blackening solution. The purpose is to maintain the viscosity and permeability of the blackening solution, while ensuring that the rate of the blackening reaction is not too slow due to too low a temperature, nor that the solvent evaporates too quickly due to too high a temperature, resulting in uneven blackening.

[0094] Furthermore, the periodic up-and-down movement period is 0.5-20s, for example, it can be 0.5s, 2s, 5s, 10s, or 20s.

[0095] It should be noted that the periodic up-down movement cycle refers to the time required to complete one complete "rise-contact solder strip-fall" process cycle. A suitable movement cycle can effectively control the length of a single coating area and the spacing between adjacent coating areas.

[0096] In another embodiment, the present invention provides a black photovoltaic solder ribbon 7, such as Figure 3 As shown, the black photovoltaic ribbon 7 is prepared using the preparation method described above.

[0097] The black photovoltaic ribbon 7 includes a photovoltaic ribbon substrate 71 and a black coating 72 discontinuously distributed on one side surface of the photovoltaic ribbon substrate 71.

[0098] Furthermore, the photovoltaic ribbon substrate 71 is a bus ribbon or an interconnect ribbon. For example, it could be Sn. 60 Pb 40 Solder ribbon or lead-free solder ribbon, etc.

[0099] Furthermore, the black coating 72 is a PbS coating or a SnS coating.

[0100] In this invention, this type of black coating is suitable for sponge layers because the blackening liquid has suitable surface tension and viscosity, allowing it to be fully adsorbed and uniformly wetted by the porous structure of the sponge layer. It also has no chemical compatibility issues with sponge materials (such as polyurethane), and during the transfer process, it will not corrode the sponge fibers. Furthermore, it can achieve close adhesion and blackening reaction with the surface of the photovoltaic ribbon due to the elastic deformation of the sponge, ensuring blackening efficiency and thickness uniformity. On the other hand, the PbS or SnS coating is amorphous, matte black, and has good uniformity. It is not prone to delamination or cracking when bent, making it suitable for various ribbons (e.g., SnS). 60Pb 40 Solder ribbon, lead-free solder ribbon, etc.

[0101] Furthermore, the thickness of the black coating 72 is 0.15-0.55μm, for example, it can be 0.15μm, 0.25μm, 0.35μm, 0.45μm or 0.55μm, etc.

[0102] Furthermore, in the black coating 72, the length of a single coating area is 5-200mm, for example, it can be 5mm, 20mm, 50mm, 100mm or 200mm, etc.

[0103] Furthermore, in the black coating 72, the spacing between adjacent coating areas is 5-200mm, for example, it can be 5mm, 20mm, 50mm, 100mm or 200mm.

[0104] In this invention, the appropriate length of a single coating area, combined with the appropriate spacing between adjacent coating areas, ensures that the unblackened spacing has sufficient welding width, while also ensuring the consistency and stability of the process between adjacent coating areas.

[0105] Example 1

[0106] This embodiment provides a method for preparing black photovoltaic solder ribbon, the method comprising the following steps:

[0107] (1) The busbar roll is unwound using an unwinding shaft; the busbar roll is made of tin-plated copper strip.

[0108] (2) The busbar roll is conveyed to the blackening assembly at a speed of 2.5 m / min. By controlling the periodic up and down movement of the blackening wheel in the blackening assembly, the sponge layer in the blackening wheel, which is soaked in blackening liquid, comes into intermittent rotational contact with the busbar roll during the movement, and reacts to form a single-sided intermittently distributed SnS coating.

[0109] The blackening wheel rotates at 10 rpm, and the radial thickness of the porous blackening liquid guide cavity is 40 mm; the viscosity of the blackening liquid is 1 mPa·s, and the concentration is 15 wt%; the temperature of the blackening liquid in the sponge layer impregnated with the blackening liquid is 35°C; the periodic up-and-down movement cycle is 1 s; the thickness of the PbS coating is 0.35 μm; and in the SnS coating, the length of a single coating area is 40 mm, and the spacing between adjacent coating areas is 40 mm.

[0110] Example 2

[0111] This embodiment provides a method for preparing black photovoltaic solder ribbon, the method comprising the following steps:

[0112] (1) The busbar roll is unwound using an unwinding shaft; the busbar roll is made of tin-plated copper strip.

[0113] (2) The busbar roll is conveyed to the blackening assembly at a speed of 0.5 m / min. By controlling the periodic up and down movement of the blackening wheel in the blackening assembly, the sponge layer in the blackening wheel, which is soaked in blackening liquid, is in intermittent rotational contact with the busbar roll during the movement, forming a single-sided intermittent SnS coating.

[0114] The blackening wheel rotates at a speed of 2 rpm, and the radial thickness of the porous blackening liquid guide cavity is 40 mm; the viscosity of the blackening liquid is 0.5 mPa·s, and the concentration is 12 wt%; the temperature of the blackening liquid in the sponge layer impregnated with the blackening liquid is 20°C; the periodic up-and-down movement cycle is 3 s; the thickness of the SnS coating is 0.15 μm; and the length of a single coating area in the SnS coating is 25 mm, and the spacing between adjacent coating areas is 25 mm.

[0115] Example 3

[0116] This embodiment provides a method for preparing black photovoltaic solder ribbon, the method comprising the following steps:

[0117] (1) The busbar roll is unwound using an unwinding shaft; the busbar roll is made of tin-plated copper strip.

[0118] (2) The busbar roll is conveyed to the blackening assembly at a speed of 5 m / min. By controlling the periodic up and down movement of the blackening wheel in the blackening assembly, the sponge layer in the blackening wheel, which is soaked in blackening liquid, is in intermittent rotational contact with the busbar roll during the movement, forming a single-sided intermittent SnS coating.

[0119] The blackening wheel rotates at 10 rpm, and the radial thickness of the porous blackening liquid guide cavity is 80 mm; the viscosity of the blackening liquid is 1.5 mPa·s, and the concentration is 18 wt%; the temperature of the blackening liquid in the sponge layer impregnated with the blackening liquid is 50°C; the periodic up-and-down movement cycle is 1 s; the thickness of the PbS / SnS coating is 0.55 μm; in the SnS coating, the length of a single coating area is 83 mm, and the spacing between adjacent coating areas is 83 mm.

[0120] Example 4

[0121] The difference between this embodiment and Embodiment 1 is that the rotation speed of the blackening wheel is 0.05 rpm.

[0122] The remaining preparation methods and parameters are consistent with those in Example 1.

[0123] Example 5

[0124] The difference between this embodiment and Embodiment 1 is that the rotation speed of the blackening wheel is 200 rpm.

[0125] The remaining preparation methods and parameters are consistent with those in Example 1.

[0126] Example 6

[0127] The difference between this embodiment and Embodiment 1 is that the viscosity of the blackening liquid is 20 mPa·s.

[0128] The remaining preparation methods and parameters are consistent with those in Example 1.

[0129] Example 7

[0130] The difference between this embodiment and Embodiment 1 is that the blackening liquid is replaced with black ink.

[0131] The remaining preparation methods and parameters are consistent with those in Example 1.

[0132] Performance testing

[0133] The black photovoltaic solder ribbon provided in the above embodiments was subjected to light absorption rate testing and corrosion resistance testing.

[0134] The light absorptivity test method is as follows: The reflectance is measured using a spectrophotometer within the wavelength range of 300-1200 nm. The light absorptivity is calculated using the formula: Light absorptivity = 1 - Reflectance. The corrosion resistance test method is as follows: The black photovoltaic ribbon is placed in a sealed environment of 85℃ neutral salt spray (composition: 5% sodium chloride solution, pH 6.5-7.2), and the time when the first corrosion rust appears on the black coating surface is observed and recorded.

[0135] The results are shown in Table 1.

[0136] Table 1

[0137]

[0138] analyze:

[0139] As shown in Table 1, based on the preparation device provided by the present invention and in conjunction with a specific preparation process, the obtained black photovoltaic ribbon not only has a high light absorption rate, but also has a stable structure and good corrosion resistance.

[0140] As can be seen from the comparison between Example 1 and Examples 4-5, if the rotation speed of the blackening wheel is too slow, the blackening liquid will accumulate excessively on the surface of the busbar, the coating will be locally too thick and "sagging" will occur, resulting in increased surface roughness and decreased light absorption rate. At the same time, the bonding force between the thick film and the tin layer will become poor, and rapid peeling will occur under salt spray, significantly shortening the corrosion resistance time. If the rotation speed of the blackening wheel is too fast, the amount of blackening liquid transferred will be insufficient, the coating will become thinner and the coverage will be discontinuous, the exposed tin layer will be directly exposed to the corrosive medium, pitting corrosion will occur prematurely, and the light absorption rate and corrosion resistance will decrease simultaneously.

[0141] As can be seen from the comparison between Example 1 and Example 6, if the viscosity of the blackening liquid is too high, the penetration and spreading ability of the blackening liquid will decrease, the sponge layer will be released unevenly, and a "spot-like" discontinuous film will be formed; and it will accelerate local corrosion, resulting in a significant deterioration of light absorption rate and corrosion resistance.

[0142] A comparison of Examples 1 and 7 shows that if the blackening solution is replaced with black ink, the organic pigment system and the tin layer only physically adhere, the ethanol solvent has poor solubility for the ink, and the coating porosity is >30%; salt spray quickly penetrates into the copper substrate along the pores, and red rust appears within 24 hours, the corrosion resistance time is drastically reduced, while the light absorption rate only decreases slightly due to the high tinting strength of the ink itself.

[0143] It should be noted that the present invention is illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An apparatus for preparing a black photovoltaic solder strip, characterized by, The preparation device is equipped with an unwinding component, a blackening component, and a winding component along the conveying direction of the photovoltaic welding strip to be processed. The blackening component includes a blackening liquid supply device and a blackening wheel. The blackening wheel is equipped with a lifting drive mechanism, which is used to drive the blackening wheel to move up and down periodically, so as to realize the blackening wheel and the blackening surface of the photovoltaic welding strip to be processed in intermittent rotational contact. The blackening wheel includes, from the inside to the outside in the radial direction, a wheel axle, a porous blackening liquid guide cavity, and a sponge layer. The blackening liquid permeates into the sponge layer through the porous blackening liquid guide cavity to achieve single-sided intermittent blackening of the photovoltaic welding strip to be processed after passing through the blackening wheel.

2. The preparation device according to claim 1, characterized in that The blackening component also includes a fixed platform, on which the lifting drive mechanism is provided; The lifting drive mechanism includes a cylinder cavity and a lifting shaft; a limit ring is provided at one end of the lifting shaft that extends into the cylinder cavity to limit the axial movement stroke of the lifting shaft; the other end of the lifting shaft is connected to the wheel axle axis through a rotary sealing joint to drive the blackened wheel to perform periodic lifting motion. The bottom of the cylinder cavity is provided with an air inlet and outlet for introducing or discharging gas, thereby driving the lifting shaft to perform periodic lifting and lowering movements, achieving intermittent rotational contact between the sponge layer and the photovoltaic welding strip. The axle, the porous blackening liquid guide cavity, and the sponge layer move up and down synchronously under the drive of the lifting shaft, and the axle rotates freely relative to the lifting shaft; the axle rotates synchronously with the porous blackening liquid guide cavity.

3. The preparation device according to claim 1 or 2, characterized in that The blackening liquid supply device is a blackening liquid storage tank; The porous blackening liquid guiding cavity is provided with a liquid inlet, and the liquid inlet is connected to the liquid outlet of the blackening liquid storage tank through a pipeline; a solenoid valve is provided on the pipeline. And / or, the porous blackening liquid guiding cavity is a porous hollow annular cavity, the chamber of the hollow annular cavity is used to store the blackening liquid, and the blackening liquid is transported to the sponge layer through the porous structure of the hollow annular cavity.

4. The preparation device according to any one of claims 1 to 3, characterized in that The deformation of the sponge layer is 1-5 mm; And / or, the radial thickness of the sponge layer is 2-20 mm; And / or, the axial width of the sponge layer is greater than or equal to the width of the photovoltaic ribbon to be processed.

5. The preparation device according to any one of claims 1 to 4, characterized in that The radial thickness of the porous blackening liquid guiding cavity is 10-200 mm; And / or, the axial width of the porous blackening liquid guiding cavity is equal to the axial width of the sponge layer; And / or, the porosity of the porous blackening liquid guiding cavity is 10-80%; And / or, the average pore diameter of the porous blackening liquid guiding cavity is 0.2-2 mm.

6. The preparation device according to any one of claims 1 to 5, characterized in that A guide component is also provided between the unwinding component and the blackening component to guide and calibrate the photovoltaic welding strip output by the unwinding component, so that the photovoltaic welding strip is kept in a horizontal conveying posture and connected to the processing station of the blackening component.

7. A method of producing a black photovoltaic solder strip, characterized by, The preparation method is carried out in the preparation apparatus according to any one of claims 1-6, and includes the following steps: Unwind the photovoltaic welding strip to be processed and transport it to the blackening module. By controlling the periodic up-and-down movement of the blackening wheel in the blackening module, the sponge layer in the blackening wheel, which is wetted with blackening liquid, comes into intermittent rotational contact with the photovoltaic welding strip to be processed during the movement, forming a blackening coating with a single-sided intermittent distribution. The black photovoltaic ribbon is obtained by rewinding using a winding assembly.

8. The preparation method according to claim 7, characterized in that, The moving speed of the photovoltaic welding strip to be processed is 0.5-5 m / min; And / or, the rotation speed of the blackening wheel is 0.1-100 rpm; And / or, in the sponge layer impregnated with blackening liquid, the temperature of the blackening liquid is 20-50℃; And / or, the periodic up-and-down movement period is 0.5-20s.

9. A black photovoltaic welding ribbon, characterized in that, The black photovoltaic ribbon is prepared using the preparation method described in claim 7 or 8; The black photovoltaic ribbon includes a photovoltaic ribbon substrate and a black coating that is intermittently distributed on one side surface of the photovoltaic ribbon substrate.

10. The black photovoltaic solder strip of claim 9, wherein, The photovoltaic ribbon substrate is a bus ribbon or an interconnect ribbon; And / or, the black coating is a PbS coating or a SnS coating; And / or, the thickness of the black coating is 0.15-0.55 μm; And / or, in the black coating, the length of a single coating area is 5-200 mm; And / or, in the black coating, the spacing between adjacent coating areas is 5-200 mm.

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