Photovoltaic module and method of manufacturing the same

Abstract

The application relates to a photovoltaic module and a preparation method thereof. The photovoltaic module comprises a plurality of cell strings, a plurality of bus bars and at least one jumper; the cell string comprises a plurality of photovoltaic cells connected in series through a welding strip; the plurality of cell strings are electrically connected through the bus bars; the bus bar comprises a first main body layer, the first main body layer has a first surface and a second surface oppositely arranged along the thickness direction thereof, and a first solder layer is arranged on the first surface; the first solder layer covers at least the region where the first surface and the welding strip are in contact; the two adjacent bus bars are connected through the jumper; a second solder layer is arranged on the second surface; the second solder layer covers at least the region where the second surface and the jumper are in contact; and the melting point of the second solder layer is 75 DEG C to 125 DEG C lower than that of the first solder layer. The photovoltaic module can reduce the traction tension of the jumper thermal expansion on the bus bar and reduce the problem of virtual welding.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to photovoltaic modules and their manufacturing methods. Background Technology

[0002] With the rapid development of the photovoltaic industry, photovoltaic modules, as the core component of solar power generation systems, have undergone continuous optimization in structural design and manufacturing processes. Currently, photovoltaic modules typically consist of multiple photovoltaic cells connected in series via solder ribbons to form a cell string, and then multiple cell strings are connected in parallel / series via busbars. Simultaneously, to address issues such as circuit continuity during the series / parallel connection of cells, jumpers are introduced into photovoltaic modules to optimize circuit connections. In photovoltaic modules, the connection quality of cells, solder ribbons, busbars, and jumpers directly affects the power generation efficiency and lifespan of the photovoltaic module. In traditional photovoltaic modules, jumpers expand due to heat in the laminator, easily pulling on the head and tail busbars and causing the solder ribbons of the cells to detach, resulting in poor soldering. Summary of the Invention

[0003] Therefore, it is necessary to provide a photovoltaic module and its manufacturing method. The photovoltaic module of this application can reduce the traction force on the busbar caused by the thermal expansion of jumpers, and reduce the problem of poor soldering.

[0004] In a first aspect, this application provides a photovoltaic module, comprising: a plurality of cell strings, a plurality of busbars, and at least one jumper;

[0005] The battery string includes multiple photovoltaic cells connected in series by solder strips; the multiple battery strings are electrically connected by the busbar; the busbar includes a first body layer, the first body layer has a first surface and a second surface disposed opposite to each other along its thickness direction, a first solder layer is disposed on the first surface; the first solder layer at least covers the area where the first surface and the solder strip are in contact.

[0006] Two adjacent busbars are connected by jumpers; a second solder layer is provided on the second surface; the second solder layer at least covers the area where the second surface and the jumper are in contact; the melting point of the second solder layer is 75°C to 125°C lower than the melting point of the first solder layer.

[0007] In some embodiments, the jumper includes a second body layer on which a third solder layer is disposed; the third solder layer at least covers the area where the second body layer and the second surface are in contact, the third solder layer and the second solder layer are soldered together, and the difference between the melting point of the third solder layer and the melting point of the second solder layer is less than or equal to 20°C.

[0008] In some embodiments, the melting point of the second solder layer is 120°C to 140°C; the melting point of the third solder layer is 120°C to 140°C.

[0009] In some embodiments, the materials of the second solder layer and the third solder layer each independently comprise at least one material having the following general chemical formula: Sn a Bi b X c Where a+b+c=1, 25%≤a≤50%, 20%≤b≤60%, 0≤c≤40%, and X includes at least one of Ag, Cu, Pb, Sb, and In.

[0010] In some embodiments, the solder strip includes a third body layer, on which a fourth solder layer is disposed; the fourth solder layer at least covers the area where the third body layer and the first surface are in contact, the fourth solder layer and the first solder layer are soldered together, and the difference between the melting point of the fourth solder layer and the melting point of the first solder layer is less than or equal to 30°C.

[0011] In some embodiments, the melting point of the fourth solder layer is 215°C to 245°C; the melting point of the first solder layer is 215°C to 245°C.

[0012] In some embodiments, the materials of the first solder layer and the fourth solder layer each independently comprise at least one material having the following general chemical formula: Sn d Pb e Y f Where d+e+f=1, 30%≤d≤70%, 20%≤e≤70%, 0≤f≤10%, and Y includes at least one of Ag, Sb and Bi.

[0013] In some embodiments, the welding pull force between the busbar and the jumper is ≥20N.

[0014] In some embodiments, there are multiple jumpers, which are spaced apart; each jumper is located between different battery strings.

[0015] In some embodiments, a cover plate and an encapsulation layer are also included;

[0016] The encapsulation layer is located between the cover plate and the battery string, and the cover plate is connected to the battery string through the encapsulation layer.

[0017] Secondly, this application provides a method for preparing a photovoltaic module, comprising the following steps:

[0018] The system provides multiple battery strings, multiple busbars, and at least one jumper; the battery strings include multiple photovoltaic cells connected in series by solder strips; the busbars include a first body layer having a first surface and a second surface disposed opposite to each other.

[0019] A first solder paste is applied to the first surface; a first soldering process is performed to form a first solder layer from the first solder paste, and the first solder layer is controlled to at least cover the area where the first surface and the solder strip are in contact. The multiple battery strings are electrically connected through the busbar.

[0020] A second solder paste is applied to the second surface, the melting point of the second solder paste being 75°C to 125°C lower than that of the first solder paste; a second soldering process is performed to form a second solder layer from the second solder paste, and the second solder layer is controlled to at least cover the area of ​​the second surface and the jumper wire in contact, and two adjacent busbars are connected by the jumper wire.

[0021] In some embodiments, the temperature of the first welding process is 230°C to 260°C.

[0022] In some embodiments, the temperature of the second welding process is 145°C to 150°C.

[0023] In the aforementioned photovoltaic module, by setting solder layers with different melting points on the first and second surfaces of the busbar, where the melting point of the second solder layer is 75°C to 125°C lower than that of the first solder layer, the jumper wire and the busbar are welded together through the low-temperature solder layer during the photovoltaic module lamination process. The high-temperature solder layer between the busbar and the solder strip does not melt, effectively solving the problem of incomplete soldering of the cell solder strip caused by the thermal expansion of the jumper wire pulling the busbar during lamination. Furthermore, using the technical solution of this application, the welding pull force between the busbar and the jumper wire can reach over 20N, ensuring the reliability and stability of the photovoltaic module in actual use, while also improving the production yield of the photovoltaic module. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a photovoltaic module provided in one embodiment of this application;

[0025] Figure 2 A schematic diagram of the structure of a photovoltaic module provided in another embodiment of this application;

[0026] Figure 3 This is a schematic diagram of the structure of a photovoltaic module provided in another embodiment of this application.

[0027] Explanation of reference numerals in the attached figures:

[0028] 10-Photovoltaic cell; 20-Cell string; 30-Busbar; 31-First main body layer; 32-First solder layer; 33-Second solder layer; 40-Jumper wire; 41-Second main body layer; 42-Third solder layer; 50-Solder ribbon; 51-Third main body layer; 52-Fourth solder layer. Detailed Implementation

[0029] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0030] Unless otherwise defined, 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 belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation of this application.

[0032] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] In photovoltaic (PV) modules, the connection quality of cells, solder ribbons, busbars, and jumpers directly affects the module's power generation efficiency and lifespan. Especially in multi-cell modules (such as those using a three-string, four-parallel circuit design), jumpers expand due to heat in the laminator, easily pulling on the beginning and end busbars, causing the cell solder ribbons to detach and resulting in poor soldering. This is mainly because the welding structure between the busbars and jumpers in traditional PV modules fails to effectively cope with the stress caused by thermal expansion. When the module is heated during lamination, the thermal expansion coefficient of the jumpers does not match that of other components, and the resulting stress is transmitted to the connection between the busbars and the cell solder ribbons, leading to unstable connections.

[0035] Based on this, refer to Figure 1 , Figure 2 As shown, one embodiment of this application provides a photovoltaic module, including: a plurality of cell strings 20, a plurality of busbars 30, and at least one jumper 40; the cell strings 20 include a plurality of photovoltaic cells 10 connected in series by solder ribbons 50; the plurality of cell strings 20 are electrically connected by busbars 30; the busbar 30 includes a first body layer 31, the first body layer 31 having a first surface and a second surface disposed opposite to each other along its thickness direction, a first solder layer 32 disposed on the first surface; the first solder layer 32 at least covers the area where the first surface and the solder ribbons 50 are in contact; two adjacent busbars 30 are connected by jumper 40; a second solder layer 33 is disposed on the second surface; the second solder layer 33 at least covers the area where the second surface and the jumper 40 are in contact; the melting point of the second solder layer 33 is 75°C to 125°C lower than the melting point of the first solder layer 32.

[0036] In the aforementioned photovoltaic module, by setting solder layers with different melting points on the first and second surfaces of the busbar 30, where the melting point of the second solder layer 33 is 75°C to 125°C lower than that of the first solder layer 32, the jumper 40 and the busbar 30 are welded together through the low-temperature solder layer during the photovoltaic module lamination process. Meanwhile, the high-temperature solder layer between the busbar 30 and the solder strip 50 does not melt, effectively solving the problem of the jumper 40's thermal expansion pulling the busbar 30 during lamination, leading to incomplete soldering of the cell solder strip 50. Through this structural design, particularly the use of solder layers with different melting points, the photovoltaic module of this application can be welded in stages during manufacturing, first completing the high-melting-point solder and then the low-melting-point solder. This avoids affecting the already welded parts during subsequent welding processes, improving the manufacturing efficiency and quality stability of the photovoltaic module, as well as its reliability and lifespan.

[0037] Optionally, the melting point of the second solder layer 33 may be 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, or 125°C lower than the melting point of the first solder layer 32. Alternatively, the value by which the melting point of the second solder layer 33 is lower than the melting point of the first solder layer 32 may also be within the range between any two of the above-mentioned temperatures.

[0038] It is understood that the first solder layer 32 at least covers the area where the first surface and the solder strip 50 are in contact, meaning that, for example... Figure 2 As shown, the first solder layer 32 may only cover the area of ​​the first surface that contacts the solder strip 50, or the area of ​​the first solder layer 32 covering the first surface may be larger than the area that contacts the solder strip 50, or, as... Figure 3 As shown, the first solder layer 32 covers the entire first surface.

[0039] It is understood that the second solder layer 33 at least covers the area where the second surface and the jumper 40 contact, meaning that, as Figure 2 As shown, the second solder layer 33 may only cover the area of ​​the second surface that contacts the jumper 40, or the area covered by the second solder layer 33 on the second surface may be larger than the area that contacts the jumper 40, or, as... Figure 3 As shown, the second solder layer 33 covers the entire second surface.

[0040] In some embodiments, the photovoltaic cell 10 includes at least one of silicon-based solar cells.

[0041] In some embodiments, the photovoltaic cell 10 includes at least one of a passivated emitter and back contact cell (PERC cell), a tunnel oxide passivated contact cell (TOPCon cell), a heterojunction cell (HJT cell), and a back contact cell (BC cell).

[0042] In some embodiments, the material of the first body layer 31 includes copper.

[0043] In some embodiments, the jumper 40 includes a second body layer 41, on which a third solder layer 42 is disposed; the third solder layer 42 at least covers the area of ​​the second body layer 41 in contact with the second surface, the third solder layer 42 and the second solder layer 33 are soldered together, and the difference between the melting point of the third solder layer 42 and the melting point of the second solder layer 33 is less than or equal to 20°C.

[0044] Similarly, the third solder layer 42 may cover only the area of ​​the second body layer 41 that contacts the second surface, or it may cover the entire surface of the second body layer 41 facing the second surface. Optionally, the difference between the melting point of the third solder layer 42 and the melting point of the second solder layer 33 is 0~20℃. More optionally, the difference between the melting point of the third solder layer 42 and the melting point of the second solder layer 33 is 0, 1℃, 2℃, 3℃, 4℃, 5℃, 6℃, 7℃, 8℃, 9℃, 10℃, 11℃, 12℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, 19℃, or 20℃. Alternatively, the difference between the melting point of the third solder layer 42 and the melting point of the second solder layer 33 may also be within the range of any two of the above differences.

[0045] In some embodiments, the material of the second body layer 41 includes copper.

[0046] In some embodiments, the melting point of the second solder layer 33 is 120°C to 140°C; the melting point of the third solder layer 42 is 120°C to 140°C.

[0047] Within the melting point range of the second solder layer 33 and the third solder layer 42, it is convenient to form a good solder connection between the busbar 30 and the jumper 40 during the fabrication of the photovoltaic module, while also reducing the impact on the connection stability of other components. Optionally, the melting point of the second solder layer 33 is 120℃, 122℃, 124℃, 126℃, 128℃, 130℃, 132℃, 134℃, 136℃, 138℃, or 140℃, or the melting point of the second solder layer 33 may also be within the range between any two of the above melting points. Optionally, the melting point of the third solder layer 42 is 120℃, 122℃, 124℃, 126℃, 128℃, 130℃, 132℃, 134℃, 136℃, 138℃, or 140℃, or the melting point of the third solder layer 42 may also be within the range between any two of the above melting points.

[0048] In some embodiments, the materials of the second solder layer 33 and the third solder layer 42 each independently comprise at least one material having the following general chemical formula: Sna Bi b X c Where a+b+c=1, 25%≤a≤50%, 20%≤b≤60%, 0≤c≤40%, and X includes at least one of Ag, Cu, Pb, Sb, and In.

[0049] The materials of the second solder layer 33 and the third solder layer 42 each independently include at least one of the materials having the above-mentioned general chemical formula, which facilitates the realization that the melting point of the second solder layer 33 is 120℃~140℃; the melting point of the third solder layer 42 is 120℃~140℃, and the difference between the melting point of the third solder layer 42 and the melting point of the second solder layer 33 is less than or equal to 20℃, which facilitates the formation of a good welding connection between the busbar 30 and the jumper 40 during the manufacturing process of the photovoltaic module, and also reduces the impact on the connection stability of other components.

[0050] Alternatively, a can be 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, or 50%, or a can be within the range of any two of the above values.

[0051] Alternatively, b can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or 60%, or b can be within the range of any two of the above values.

[0052] Alternatively, c can be 0, 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%, or c can be within the range of any two of the above values.

[0053] In some embodiments, the materials of the second solder layer 33 and the third solder layer 42 each independently include at least one of Sn 42%-Bi 58%, Sn 48%-Bi 32.5%-In 19.5%, Sn 43%-Bi 21%-Pb 36%, Sn 42%-Bi 57%-Ag 1%, Sn 28%-Bi 27%-Sb 1.5%-Cu 0.05%-Pb 53.45%. It is understood that the above chemical formulas refer to alloy materials composed of elements in percentage proportions.

[0054] In some embodiments, the solder strip 50 includes a third body layer 51, on which a fourth solder layer 52 is disposed; the fourth solder layer 52 at least covers the area where the third body layer 51 and the first surface are in contact, the fourth solder layer 52 and the first solder layer 32 are soldered together, and the difference between the melting point of the fourth solder layer 52 and the melting point of the first solder layer 32 is less than or equal to 30°C.

[0055] Similarly, the fourth solder layer 52 may only cover the area where the third main layer 51 contacts the first surface, or it may cover the entire surface of the third main layer 51 facing the first surface. Optionally, the difference between the melting point of the fourth solder layer 52 and the melting point of the first solder layer 32 may be 0, 2°C, 5°C, 8°C, 10°C, 12°C, 15°C, 18°C, 20°C, 22°C, 25°C, 28°C, or 30°C, or the difference between the melting point of the fourth solder layer 52 and the melting point of the first solder layer 32 may be within any two of the above-mentioned differences.

[0056] In some embodiments, the material of the fourth body layer includes copper.

[0057] In some embodiments, the melting point of the fourth solder layer 52 is 215°C to 245°C; the melting point of the first solder layer 32 is 215°C to 245°C.

[0058] Within the melting point range of the fourth solder layer 52 and the first solder layer 32, a stable electrical connection between the busbar 30 and the solder ribbon 50 can be easily achieved, while also preventing damage to the photovoltaic cell 10 during the soldering process due to excessively high melting points. Optionally, the melting point of the fourth solder layer 52 is 215°C, 218°C, 220°C, 222°C, 225°C, 228°C, 230°C, 232°C, 235°C, 238°C, 240°C, 242°C, or 245°C, or the melting point of the fourth solder layer 52 can be within the range between any two of the above melting points. Optionally, the melting point of the first solder layer 32 is 215°C, 218°C, 220°C, 222°C, 225°C, 228°C, 230°C, 232°C, 235°C, 238°C, 240°C, 242°C, or 245°C. Alternatively, the melting point of the first solder layer 32 may be within the range of any two of the above melting points.

[0059] In some embodiments, the materials of the first solder layer 32 and the fourth solder layer 52 each independently include at least one material having the following general chemical formula: Sn d Pb e Y f Where d+e+f=1, 30%≤d≤70%, 20%≤e≤70%, 0≤f≤10%, and Y includes at least one of Ag, Sb and Bi.

[0060] The materials of the first solder layer 32 and the fourth solder layer 52 each independently include at least one of the materials having the aforementioned general chemical formula. This facilitates achieving a melting point of 215°C to 245°C for both the fourth solder layer 52 and the first solder layer 32, with the difference between their melting points being less than or equal to 30°C. This ensures a good welding effect between the busbar 30 and the solder strip 50, guaranteeing the reliability and stability of the electrical connection of the photovoltaic module during long-term use. Furthermore, the higher melting point of the solder layer effectively prevents loosening or disconnection of the connection due to factors such as changes in ambient temperature or mechanical vibration.

[0061] Alternatively, d can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%, or d can be within the range of any two of the above percentages.

[0062] Optionally, e can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%, or e can be within the range of any two of the above percentages.

[0063] Alternatively, f can be 0, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, or f can be within the range of any two of the above percentages.

[0064] In some embodiments, the materials of the first solder layer 32 and the fourth solder layer 52 each independently include at least one of Sn50%-Pb48%-Ag2%, Sn37%-Pb60%-Ag3%, Sn30%-Pb60%-Sb10%, Sn40%-Pb55%-Sb5%, Sn35%-Pb60%-Sb5%, and Sn35%-Pb55%-Bi10%. It is understood that the above chemical formulas refer to alloy materials composed of elements in percentage proportions.

[0065] In some embodiments, the welding pull force between the busbar 30 and the jumper 40 is ≥20N.

[0066] Furthermore, by adopting the technical solution of this application, the welding pull force between the busbar 30 and the jumper 40 can reach more than 20N, which ensures the reliability and stability of the photovoltaic module in actual use, and at the same time improves the production yield of the photovoltaic module.

[0067] In some embodiments, there are multiple jumpers 40, which are spaced apart; each jumper 40 is located between different battery strings 20.

[0068] In this photovoltaic module, there are multiple jumpers 40, which are spaced apart and connected to different cell strings 20. This design increases the electrical redundancy between the cell strings 20. Even if one jumper 40 fails, the other jumpers 40 can still ensure normal current conduction, thus improving the reliability and lifespan of the photovoltaic module.

[0069] In some embodiments, a cover plate and an encapsulation layer are also included;

[0070] The encapsulation layer is located between the cover plate and the battery string 20, and the cover plate is connected to the battery string 20 through the encapsulation layer.

[0071] Another embodiment of this application provides a method for preparing a photovoltaic module, comprising the following steps:

[0072] Provided are multiple battery strings 20, multiple busbars 30 and at least one jumper 40; the battery strings 20 include multiple photovoltaic cells 10 connected in series by solder strips 50; the busbars 30 include a first body layer 31, the first body layer 31 having a first surface and a second surface disposed opposite to each other;

[0073] A first solder paste is applied to a first surface; a first soldering process is performed to form a first solder layer 32, and the first solder layer 32 is controlled to at least cover the area where the first surface and the solder strip 50 are in contact. Multiple battery strings 20 are electrically connected through a busbar 30.

[0074] A second solder paste is applied to the second surface. The melting point of the second solder paste is 75°C to 125°C lower than that of the first solder paste. A second soldering process is performed to form a second solder layer 33. The second solder layer 33 is controlled to at least cover the area where the second surface and the jumper 40 are in contact. Two adjacent busbars 30 are connected by the jumper 40.

[0075] In the aforementioned photovoltaic module fabrication method, the use of solder pastes with different melting points for step-by-step soldering effectively solves the problem of secondary soldering causing the first solder to melt, which is prone to occur in traditional photovoltaic module fabrication processes. This significantly improves soldering quality and module reliability. Photovoltaic modules fabricated using the aforementioned method can reduce solder joint detachment rate and improve electrical performance stability.

[0076] In some embodiments, the temperature of the first welding process is 230°C to 260°C.

[0077] Optionally, the temperature of the first welding process is 230°C, 232°C, 235°C, 238°C, 240°C, 242°C, 245°C, 248°C, 250°C, 252°C, 255°C, 258°C, or 260°C, or the temperature of the first welding process may be within the range of any two of the above temperatures.

[0078] In some embodiments, the temperature of the second welding process is 145°C to 150°C.

[0079] Optionally, the temperature of the second welding process is 145°C, 146°C, 147°C, 148°C, 149°C, or 150°C, or the temperature of the second welding process may be within the range of any two of the above temperatures.

[0080] 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.

[0081] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A photovoltaic module, characterized in that, include: Multiple battery strings, multiple busbars, and at least one jumper; The battery string includes multiple photovoltaic cells connected in series by solder strips; Multiple battery strings are electrically connected via the busbar; the busbar includes a first body layer, the first body layer having a first surface and a second surface disposed opposite to each other along its thickness direction, a first solder layer being disposed on the first surface; the first solder layer at least covers the area where the first surface and the solder strip are in contact. Two adjacent busbars are connected by the jumper wire; A second solder layer is provided on the second surface; the second solder layer at least covers the area where the second surface and the jumper are in contact; the melting point of the second solder layer is 75°C to 125°C lower than the melting point of the first solder layer.

2. The photovoltaic module according to claim 1, characterized in that, The jumper includes a second body layer, on which a third solder layer is disposed; the third solder layer at least covers the area where the second body layer and the second surface are in contact, the third solder layer and the second solder layer are soldered together, and the difference between the melting point of the third solder layer and the melting point of the second solder layer is less than or equal to 20°C.

3. The photovoltaic module according to claim 2, characterized in that, The melting point of the second solder layer is 120℃~140℃; the melting point of the third solder layer is 120℃~140℃.

4. The photovoltaic module according to claim 3, characterized in that, The materials of the second solder layer and the third solder layer each independently include at least one material having the following general chemical formula: Sn a Bi b X c Where a+b+c=1, 25%≤a≤50%, 20%≤b≤60%, 0≤c≤40%, and X includes at least one of Ag, Cu, Pb, Sb, and In.

5. The photovoltaic module according to claim 1, characterized in that, The solder strip includes a third body layer, on which a fourth solder layer is disposed; the fourth solder layer at least covers the area where the third body layer and the first surface are in contact, the fourth solder layer and the first solder layer are soldered together, and the difference between the melting point of the fourth solder layer and the melting point of the first solder layer is less than or equal to 30°C.

6. The photovoltaic module according to claim 5, characterized in that, The melting point of the fourth solder layer is 215℃~245℃; the melting point of the first solder layer is 215℃~245℃.

7. The photovoltaic module according to claim 6, characterized in that, The materials of the first solder layer and the fourth solder layer each independently comprise at least one material having the following general chemical formula: Sn d Pb e Y f Where d+e+f=1, 30%≤d≤70%, 20%≤e≤70%, 0≤f≤10%, and Y includes at least one of Ag, Sb and Bi.

8. The photovoltaic module according to any one of claims 1 to 7, characterized in that, The welding pull force between the busbar and the jumper wire is ≥20N.

9. The photovoltaic module according to any one of claims 1 to 7, characterized in that, There are multiple jumpers, and the jumpers are spaced apart; each jumper is located between different battery strings.

10. The photovoltaic module according to any one of claims 1 to 7, characterized in that, It also includes a cover plate and a sealing layer; The encapsulation layer is located between the cover plate and the battery string, and the cover plate is connected to the battery string through the encapsulation layer.

11. A method for preparing a photovoltaic module, characterized in that, Includes the following steps: The system provides multiple battery strings, multiple busbars, and at least one jumper; the battery strings include multiple photovoltaic cells connected in series by solder strips; the busbars include a first body layer having a first surface and a second surface disposed opposite to each other. A first solder paste is applied to the first surface; A first soldering process is performed to form a first solder layer from the first solder paste. The first solder layer is controlled to at least cover the area where the first surface and the solder strip are in contact. The multiple battery strings are electrically connected through the busbar. A second solder paste is applied to the second surface, the melting point of the second solder paste being 75°C to 125°C lower than that of the first solder paste; a second soldering process is performed to form a second solder layer from the second solder paste, and the second solder layer is controlled to at least cover the area of ​​the second surface and the jumper wire in contact, and two adjacent busbars are connected by the jumper wire.

12. The method for preparing a photovoltaic module according to claim 11, characterized in that, The temperature of the first welding process is 230℃~260℃; and / or, The temperature for the second welding process is 145℃~150℃.

Images